Usability study of interactive decision support systems ... · PDF fileUsability study of interactive decision support systems and ... decision support system be developed to support

Master’s thesis in Computer Science

Usability study of interactive

decision support systems and

touch screen technology in

control room environments

Frida Bergman and Johanna Nilsson

January 27, 2006

Umeå University Department of Computing Science

&

IT University of Göteborg Göteborg University and

Chalmers University of Technology and Engineering Department of Computer Science

ABSTRACT

This master’s thesis attends to the needs in a control room at a subway corporation. The aim is to develop a software prototype to support the operators in their work and thereby enhance the safety at the subway. The aim is followed by two main questions: How can an interactive decision support system be developed to support the operator and enhance the safety? Can a new kind of workplace with a touch screen interface be more efficient than traditional solutions? To investigate these questions deeper research within the fields of decision support system and touch screen technology is made. This project was based on the operators needs and consisted mainly of four parts: a field study containing observations and interviews, a Hierarchical Task Analysis to find out the exact activities in the control room, a paper prototyping session to illustrate the solutions and be able to discuss them with the operators, and finally a software prototype which was the goal of this project and the master’s thesis. The conclusions are that a decision support system can support the user and therefore also enhance the safety at the subway. Further, a touch screen will work as a good means for manoeuvring a decision support system, but to be able to answer if it will work as a new kind of workplace further research is required. Keywords: human-computer interaction, touch screen, decision support system, control room, stress, public transport.

SAMMANFATTNING

Denna magisteruppsats uppmärksammar de behov som finns i ett kontrollrum på ett tunnelbaneföretag. Syftet är att skapa en prototyp som ska kunna stödja operatörerna i deras arbete och därmed förhöja säkerheten på tunnelbanan. Syftet följs av två huvudfrågor: Hur kan interaktiva beslutsstöd utvecklas för att stödja operatören och förhöja säkerheten? Kan en ny sorts arbetsplats bestående av en pekskärm vara mer effektiv än traditionella lösningar? En djupare undersökning inom områdena pekskärm och beslutsstöd har gjorts för att granska dessa frågor mer genomgående. Arbetsprocessen är baserad på användarnas behov och består av fyra delar: en fältstudie innehållande observationer och intervjuer, metoden Hierarchical Task Analysis för att ta reda på exakt de aktiviteter som förekommer i ett kontrollrum, en pappersprototyp-session för att illustrera lösningar och kunna diskutera dem med användarna och slutligen den mjukvaruprototyp som var målet med denna magisteruppsats. Slutsatserna är att beslutsstöd kan stödja operatören och förhöjer därmed också säkerheten. En pekskärm fungerar också som ett utmärkt redskap för att navigera inom ett beslutsstöd men för att kunna svara på om den kan fungera som en hel arbetsplats krävs ytterligare undersökningar. Nyckelord: människa-dator interaktion, pekskärm, beslutsstöd, kontrollrum, stress, kollektivtrafik.

TABLE OF CONTENTS

1 INTRODUCTION........................................................1

1.1 Goal and aim ............................................................................. 2

1.2 Research questions................................................................... 2

1.3 Limitations ................................................................................. 2

1.4 Central concepts ....................................................................... 3

2 THEORETICAL BACKGROUND ..............................5

2.1 HCI............................................................................................. 5

2.1.1 User centred design process...................................................7

2.2 DSS ........................................................................................... 8

2.2.1 HCI and the control room ........................................................8

2.2.2 Operator systems and graphical interfaces.............................10 2.2.3 Design of DSS .....................................................................12 2.2.4 Stress..................................................................................15

2.3 Touch screen technology ........................................................ 17

2.3.1 Advantages and disadvantages.............................................18 2.3.2 Interaction............................................................................19 2.3.3 Feedback.............................................................................21

2.3.4 Target characteristics ...........................................................21 2.3.4.1 Target size ..............................................................................................22 2.3.4.2 Target location .......................................................................................23 2.3.4.3 Target shape ..........................................................................................24

2.3.5 Different technologies ...........................................................25 2.3.6 Ergonomics..........................................................................28

3 METHOD ..................................................................31

3.1 Field study ............................................................................... 32

3.1.1 Observation .........................................................................32 3.1.2 Interview ..............................................................................33

3.2 HTA.......................................................................................... 33

3.3 Paper prototyping .................................................................... 34

3.4 Final prototype......................................................................... 34

4 IMPLEMENTATION .................................................35

4.1 Field study implementation ..................................................... 35

4.1.1 Observation implementation..................................................37 4.1.1.1 Information kiosk ...................................................................................37 4.1.1.2 Swedish Road Administration .............................................................37 4.1.1.3 Metro Copenhagen ...............................................................................37 4.1.1.4 SOS Alarm..............................................................................................37 4.1.1.5 The subway corporation .......................................................................37

4.1.2 Interview implementation ......................................................38

4.2 HTA implementation................................................................ 38

4.3 Paper prototype implementation ............................................. 39

4.4 Final prototype implementation............................................... 40

5 RESULTS .................................................................41

5.1 Field study result ..................................................................... 41

5.1.1 Observation result ................................................................41 5.1.1.1 Information kiosk ...................................................................................41 5.1.1.2 Swedish Road Administration .............................................................42 5.1.1.3 Metro Copenhagen ...............................................................................42 5.1.1.4 SOS Alarm..............................................................................................43 5.1.1.5 The subway corporation .......................................................................43

5.1.2 Interview result.....................................................................49 5.1.2.1 Interview with managers ......................................................................49 5.1.2.2 Interview with operators at the traffic centre .....................................50 5.1.2.3 Interview with operators at the alarm centre .....................................52

5.2 HTA result................................................................................ 54

5.3 Paper prototype result............................................................. 56

5.4 Final prototype result............................................................... 56

5.4.1 Traffic leader........................................................................59 5.4.2 Infrastructure........................................................................62

5.4.3 Team leader.........................................................................64 5.4.4 Surveillance .........................................................................65 5.4.5 Information...........................................................................66

6 ANALYSES...............................................................67

6.1 Analysis of field study.............................................................. 67

6.1.1 Workplace............................................................................67 6.1.2 Work routines.......................................................................68

6.1.3 Stress..................................................................................69 6.1.4 Communication ....................................................................70 6.1.5 System ................................................................................70

6.2 Analysis of HTA....................................................................... 72

6.3 Analysis of paper prototype..................................................... 73

6.4 Analysis of final prototype ....................................................... 73

6.4.1 Solutions to the needs ..........................................................73 6.4.1.1 Workplace...............................................................................................73 6.4.1.2 Work routines .........................................................................................74 6.4.1.3 Stress ......................................................................................................75 6.4.1.4 Communication ......................................................................................75 6.4.1.5 System ....................................................................................................76

6.4.2 User test..............................................................................77

7 DISCUSSION ...........................................................79

7.1 Method and implementation.................................................... 79

7.1.1 Field study ...........................................................................80 7.1.1.1 Observation ............................................................................................80 7.1.1.2 Interview..................................................................................................80

7.1.2 HTA.....................................................................................81 7.1.3 Paper prototyping.................................................................81 7.1.4 Final prototype .....................................................................81

7.2 Prototype ................................................................................. 82

7.2.1 DSS ....................................................................................83 7.2.2 Touch screen technology ......................................................86

7.3 Conclusions ............................................................................. 88

7.3.1 DSS ....................................................................................89

7.3.2 Touch screen technology ......................................................89

7.4 Future work.............................................................................. 90

8 ACKNOWLEDGEMENTS........................................91

REFERENCES

APPENDIX

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1 INTRODUCTION In this section an introduction including goal, aim, research questions, limitations, and central concepts of this master’s thesis, is presented to the reader. Public transport is a very important part in a country’s infrastructure. Huge amounts of people travel at the same time on bus, ferry and subway. This positive factor has unfortunately also a negative side. Large groups of innocent people can easily be reached within seconds, which is one of the reasons why public transport has become a popular target among terrorists today. Both London’s and Madrid’s subways have recently been victims of the terrible acts of terrorists and we all know about the huge damages and the fear spread after the acts on 11th September 2001 at the World Trade Center in New York. The fear strikes everyone. A feeling of peril and threat is left to all people in our society. People have become aware of the big threat, what damages it may cause, and how vulnerable you are as a traveller. The importance of safety has dramatically increased. This master’s thesis is written in the field of interaction design and focus lies on the control rooms for public transport and how safety can be further developed in this area. The factor of safety is important to examine and constantly evolve to be prepared in case of an emergency. Two rather new areas, chosen to be further examined in this master’s thesis, are decision support system and touch screen technology. What advantages and possibilities can these two areas bring to such environments? In the perspective of interaction design the user and the usability are central parts. Therefore this master’s thesis is based on the operators (the users in the control rooms) and their needs.

Introduction

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This master’s thesis is developed in cooperation with the company Infracontrol. Infracontrol is an independent system integrator offering concepts and services for infrastructure in the fields of control, surveillance, and information systems. One of the goals for Infracontrol is to keep a distance to technical solutions and rather see assignments from the user's viewpoint. One of the clients of Infracontrol is a company in charge of subway transportation (hereafter called the subway corporation). The motivation for this master’s thesis is to use the field of interaction design as a way to study and improve the work situation for the operators in the control rooms at the mentioned subway corporation.

1.1 Goal and aim

The goal and aim of this master’s thesis is to develop a prototype to encounter the needs in the control rooms, support the work situation for the operators, and thereby enhance the subway safety at the specific subway corporation.

1.2 Research questions

Two main questions are created to support the research:

How can an interactive decision support system be developed to support the operator and enhance the safety? Can a new kind of workplace with a touch screen interface be more efficient than traditional solutions?

1.3 Limitations

This project will result in a prototype, not in a complete system. The prototype is developed only to visualise the process of one specific scenario. Testing the prototype in its real environment is too complicated and could also affect the safety. Therefore sounds and pictures are added to the prototype instead, to make it more realistic.

Introduction

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1.4 Central concepts

The following concepts are used during the whole master’s thesis and are therefore presented here to give the reader a better overview.

Operator

The operators are the people working in the control rooms and the ones in charge of operating the subway. The operators in this master’s thesis are the users.

Decision Support System (DSS)

Turban, Aronson and Liang (2005, p. 852) define DSS as: “Computer-based information systems combining models and data in an attempt to solve nonstructured problems with extensive user involvement through a friendly user interface.” (Turban, Aronson & Liang 2005, p. 852)

Human Computer Interaction (HCI)

Dix, Finlay, Abowd and Beale (2004, p. 4), describe interaction as any communication between a human and a computer.

Interaction design

Preece, Rogers and Sharp (2002, p. 6) describe the area with following sentence: “By interaction design, we mean designing interactive products to support people in their everyday and working lives.” (Preece, Rogers & Sharp 2002, p. 6)

User centred design

According to Earthy, Jones, and Bevan (2001), user centred design is a process where the users of a system are in focus.

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2 THEORETICAL BACKGROUND This section presents the theoretical background of this master’s thesis, where HCI, DSS and touch screen technology are the main fields.

Three fields are in focus for research. As interaction designers the users and the way they interact with the environment are very important. Since both authors of this master’s thesis had limited knowledge and experience from control room environments a deeper investigation of what other HCI-researchers have found in this field was made. To be able to answer the two research questions of this master’s thesis the fields of decision support system and touch screen were thoroughly explored and are presented below.

2.1 HCI

In the field of HCI, the designer is concerned with understanding how people use technological products and systems and how they can be more usable. The area of HCI is young and has been around for 20 years, and is still developing. In HCI, the designer works with the technology from a humanistic perspective. The designer studies how people use technology and how they act and communicate; the connection between technology and the user is analysed. Computational products and systems are tailored for the users and their specific user situation (Carroll 2003, pp. 1-9).

Usability in a system can be different for each setting, according to Preece, Rogers, and Sharp (2002, p. 4). The aspect of usability depends on where the system is going to be used and by whom. To optimize the interaction between users and systems several

Theoretical background

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issues such as context of use, functions, tasks, and who the user is need to be analysed (Preece, Rogers & Sharp 2002, p. 4). According to Winograd (1997), the relation between interaction design and software engineering can be seen as similar to the relation between architects and civil engineers. Architects are concerned with the people and their interactions with each other and their lives within the house, while civil engineers are interested in how to realize the project. In the same way interaction designers are concerned with the people and their interaction with the software while the software engineer is interested in how to develop the software (Winograd 1997). Löwgren and Stolterman (1998, p. 7) describe that every design include several situations where the interaction designer has to be creative, and to see and analyse people, products and situations in a new way. Ottersten and Balic (2004, p. 19), describe their view of how interaction design can be a part of designing systems in the area of IT. They explain how systems have become a natural part of peoples working life, which makes it important to develop these systems in a good way. Every design decision becomes an important part of the overall result. Good design includes choosing functions, information, and graphical interfaces adjusted for the users’ needs and the active environment. It is not enough to only focus on the functions for the specific system. In detail the designer needs to analyse the situation, the users’ needs and expectations, and the benefits of the system. A working environment that lacks in efficiency can depend on IT-solutions not designed properly (Ottersten & Balic 2004, p. 19). Ottersten and Balic (2004, p. 19) further claim how IT-solutions developed to improve the work routines is no solution in itself. The authors describe how several projects are delayed and become more expensive than planned. The reason is the decision makers who do not have the right insight for what goal and effect the project should achieve. The right effect of the system or the product can be achieved if the goal and the outcome of the project are stated in the beginning of the project (Ottersten & Balic 2004, p. 19).


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2.1.1 User centred design process

The user-centred design processes for interactive systems are defined in ISO 13407, and is an international standard for how to implement user-centred design effectively. The four main principles to follow ISO 13407 are:

· The active involvement of users and clear understanding of user and task requirements.

· An appropriate allocation of function between user and system.

· Iteration of design solutions. · Multi-disciplinary design teams (ISO 13407).

Andersson and Sandblad (2003a), suggest a user centred design process to be used when developing graphical interfaces of operator systems. The motivation for this is to take advantage of the users’ competence, a central part in a user centred design process. The authors state the following main characteristics of a user centred design process as a software engineering method, used for new systems and graphical interfaces:

· The designers collaborate with the users during the whole design process. The designers should be interaction designers and the users are the real users of the system.

· The development process is iterative and the phases: analyses, design, implementation and evaluation are repeated until the results are accepted of all people involved.

· The working outcome is implemented in prototypes and can change during the whole process (Andersson & Sandblad 2003a).

Andersson and Sandblad (2003a) conclude their thoughts of a user centred design process, where systems should be functional, be able to be implemented in the technical environment, efficient, aesthetically appealing, and accepted by the user. Maguire (2001) also states the importance of a user centred design process where the benefits of designing a usable system are many: increased productivity, reduced errors, reduced support, and improved acceptance. The process is concerned with involving the users in the whole process, to achieve a system that measures usability. This key principle can enhance the acceptance and the commitment to the new software (Maguire 2001).


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2.2 DSS

In this section, different theories of DSS are stated, and in the subcategories: HCI and the control room, operator systems and graphical interfaces, design of DSS and stress.

2.2.1 HCI and the control room

According to Boring, Richard, Hugo and Dudenhoeffer (2005), the connection between HCI and control room design is important. Interaction designers adapt interface technology into control rooms to meet usability and safety. The authors’ further state how the control room environment differs from several different industries though there are several similarities such as: interfaces to simplify a complex system, safety-critical tasks, and the operators’ central role. A great challenge in the area of HCI is how to adapt useful interface solutions to control room environments. By tradition HCI interfaces must be developed to be usable and appealing, but in HCI for control rooms safety is another challenge to encounter. The important issue where the operator has to be seen as a key component is up for discussion among interaction designers (Boring et al. 2005). Several studies show how a HCI with many advantages can be used in the development process of control room- and system design. Milner and Wheeler (2001) claim that using HCI as an approach for design of control rooms can reduce the risk of safety by considering human factors as an essential part as early in the process as possible. Likewise, Gunnarsson and Gustavsson (1997) mention how they are developing a model to improve aspects of human factors and safety in a control room by building in a DSS with functions of surveillance. In the report from the project “Future train traffic control”, Andersson and Sandblad (2003a), describe basic knowledge and principles of developing and designing graphical interfaces to support the interaction between users and systems. To develop good and usable workplaces for operators much knowledge about human factors and the specific work environment are required. The general guidelines, according to Andersson and Sandblad (2003a), for designing systems to operators in control rooms are:

· The human being has a great possibility to grasp and use complex and extensive information at the same time. To be able to do this the information has to be presented in a structured way, according to human performances. There is no need to decrease the information load, but the information needs to be structured and well designed.


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· A dynamic work environment has the characteristics of being time dependent, the specific processes in the different situations needs to be identified and used as a base for interaction and presentation.

· Sometimes humans do the wrong things, an aspect important to design for. This can be catered for through developing operator system with different barriers and preventions against making wrong decisions.

· The work process of developing the interaction between a technical system and users has to be based on thorough analyses of the specific work environment and the users, in a user centred design process. The process should involve the users, and be based on prototypes and iterations.

· Developing operator systems for a specific environment, the systems have to be seen as a part of the whole environment and the activities involved. The whole organisation and competences need to be in consideration for a specific system.

· The development has to lead to a good working environment, since bad designed graphical interfaces can result in stress and inefficient work (Andersson & Sandblad 2003a).

Filippi and Theureau (1993) also indicate the importance of focusing on the complete environment including technology and how the operators interact with each other while designing control rooms. The authors claim that most studies focus on the operator as an individual and their relation to the technological environment but their study focuses on the interrelations between the operators instead. They describe their design of a graph with train movements, a system focusing on supporting the operator and the cooperative work with other operators. The DSS is optimizing current computer systems and the aim is to present a better overview and an understanding of the situation among the operators (Filippi & Theureau 1993). According to Davis (2002), working in a control room concerns influence over sometimes safety critical situations, though the operators are only humans. The author presents strategies to improve human performance, which can be concluded in the following steps: even the best can make errors; error situations can be prevented; the organisation influences the behaviour; performance is connected to


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reinforcement from leaders; and human errors can be prevented through knowledge and understanding. Davis (2002) refers to an organisation for controlling a nuclear plant and their principles of operator performance. The four principles are: open communication; prevent error situations; hold the integrity and defend the organisation; and try to improve personal capabilities. Davis (2002) states how a program to educate operators about human performance has improved the work with more practical initiatives from the operators. The education has for example developed a sense of wanting to change and improve the work, an awareness of human performances, standards for communication, and a better common feeling within the organisation (Davis 2002).

2.2.2 Operator systems and graphical interfaces

According to Andersson and Sandblad (2003a) a graphical user interface, is the interface between the operator and the system. The interface consists of how the information is presented on the display, and how the interaction between the operator and the systems works. A graphical user interface within a control room consists of all complex systems and all information systems are involved in this concept. According to Sandblad, Andersson, Byström and Kauppi (2002), the most important task for the operator involved in operating traffic, is to have a general view and awareness of the systems and at the same time be able to plan the traffic. The work involves keeping track of large amounts of information. Andersson and Sandblad (2003b) describe relevant problems important to solve when developing graphical interfaces for operating train traffic. The authors have developed a prototype for train traffic control, where the operators are responsible for a greater part of the organisation since information systems are used. The tasks the operators are involved in today are much more complex than before. The tasks are mainly to supervise and manoeuvre the process, analyse and minimise interruptions, and work as a manager of the systems. The graphical interfaces of the systems reflect and concerns how the operator work with and manage the systems. The systems show pictures of the process and in case of a disturbance an alarm will indicate this. The alarm process becomes visible more directly and includes information to help the operator to operate the process. The information of the process is general in the beginning and more detailed at the end, and results in diagnoses and suggested activities and operations (Andersson & Sandblad 2003b).


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The general guide principles Andersson and Sandblad (2003a) suggest for train traffic control system and their graphical interfaces follow:

· Design for experienced users. The users want to have all the information about the processes available in the system, though it is important that processes are well structured according to the operators’ mental models.

· The operator wants to be in control. The operators do not want to wait for alarms in the system; they want to be able to prevent situations by having total control.

· Facilitate the process for the operator. The operator needs to know how the processes work even if they are automatically operated by the system.

· The design has to be completed. The graphical interface should be locked and there is no need for the operator to be able to change the interface, such as placement of systems on the screen. During a time-critical activity, there should be a single way to perform it. Several ways to perform an activity can lead to hesitation while one single way facilitates the activity and can easily be automatic.

· Disposition of the screen. The information needs to be situated in the interface at permanent positions, and there should be a flexible way for the user to work back and forward with the information. The screen should have a finite area and designing how to present the information is very important.

· Show an overview and details at the same time, for example by showing overall and more detailed information in the same picture. Use complemented information, such as numbers, in graphical pictures to inform the operator further.

· Develop input functions well; as for example avoid the use of too many different input devices as mouse and keyboard use.

· Adjust hit functions for the work situation. If the operator moves a lot in the work, the hit areas have to be large and easy to find (Andersson & Sandblad 2003a).


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2.2.3 Design of DSS

According to Turban, Aronson and Liang (2005, p. 852, p. 860), decisions and problem solving involve a process with several alternatives to reach one or more goals. According to Norman (2000, p. 114), the selection of inappropriate goals can lead to mistakes, through misjudging the situation or by not taking all relevant factors in account. Montgomery (1992, p. 171) describes how decision is a process over time. The estimation and the judgment of the situation to be able to make a decision are limited by the human performances. To make a decision is influenced by feelings, expectations, acts, and social background. All information needs to be integrated to be able to make a reliable base before making a decision. The one who makes the decision needs to consider all information and the difficulty lies on the human performances. To integrate all information to be able to make a correct conclusion and make a decision takes time (Montgomery 1992, p. 171). Decision-making is complex and involves people and information, and a process of thinking about the problem. The need for understanding the relationship among all different aspects is important to be able to make a decision. In a DSS, complex decisions can be performed faster since the user receives a better overview (Turban, Aronson & Liang 2005, p. 37, p. 39). Jacobs (1989), mention two different objectives a DSS needs to be designed for: show the situation about which area the operator needs to make a decision and support the operator in making decisions. According to Turban, Aronson and Liang (2005, p. 231, p. 281), the reasons to use a computer aided DSS are many. Information can be stored in databases, involve pictures and sound, and can be reachable very quickly. The DSS can include data visualization with interactive graphs and models so the user can compare data to receive a clear meaning and a faster overview, which works as a support to make a decision. Norman (2000, p. 192) claims that an essential part in interaction design and technology is to make visible what otherwise is invisible. Visibility can improve feedback and the ability to keep control of, for example flight control systems, where invisible objects such as the amount of fuel can be presented graphically to the user (Norman 2000, p. 192). Integrating systems with involved information in the DSS leads to possibilities of cooperation between functions, which can complement each other and lead to several benefits. In a DSS where systems are


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integrated, the interface can provide useful functions such as presentations to match human performances and decision styles (Turban, Aronson & Liang 2005, p. 803). Hopley, Holden and Wilhelmij (1992), describe how DSS should be integrated with the whole operating process to reduce the complexity of operating. The authors also claim that the problem with DSS is that it is not sufficient to make all information available to the operator. The information needs to be carefully managed to not overload the operator’s cognitive performance. The only way to handle the implications of providing DSS, including integration, is to take a wide perspective of the complete operating process (Hopley, Holden & Wilhelmij 1992). Andersson and Sandblad (2003b) describe how they developed a DSS for traffic leaders of train traffic control, where the aim was to support decisions and to identify conflicts and disturbances in an early stage. The authors do not see any need of developing the traffic control to be fully automatic within the system. A well-developed DSS that functions in real time and which the operator uses frequently can have a tendency to counteract the knowledge of the users. Andersson and Sandblad (2003b) suggest developing the DSS with focus on enhancing the knowledge by letting the operators develop the content. The operators should have a decisive role of its development and content. The knowledge in the organisation can be reused and the operators can learn from each other (Andersson & Sandblad 2003b). Sandblad, Andersson, Byström and Kauppi (2003) further describe how the train traffic control system used in Sweden has an automatic DSS function but the operators do not use it because the situations are to complex. To avoid the automatic function the operators take manual control of the system instead, which result in the users not getting the planned support in a situation where it might be needed most. The authors suggest new concepts and strategies for a DSS giving the user better support: constant awareness, early identifying of alarms, and re-planning of decisions. In the new DSS, the train traffic controllers can be supported in their planning in real time (Sandblad et al. 2003). Boy (1998) also indicates the problems with DSS and presents a suggestion for human centred design for automated safety critical systems. For example, this can be a flight control system where the operator receives a checklist of activities to proceed. A common problem Boy (1998) mentions is the fact that the operators are not doing what the checklist requests. Another problem is that the


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operators rather use their own brain and make their own decisions no matter what the DSS gives as alternatives. Boy (1998) concludes that the operators are not good at following the procedures though they want to have full control themselves. The author suggests a more intuitive interaction between the user and the system. According to SAAB (2005) and their principle for not letting the system control the operator when developing user interfaces, one of their basic principles is that the operator must control the system and not vice versa. The automatic functions can in no way replace or steer the operator too much. Several automatic functions have to support the operator rather than replacing him/her. Grabowski and Sanborn (2003) discuss the role of technology in safety critical systems and how technology can influence operators within the system. The role of technology in these systems is to improve system performance, remove errors, and increase safety. Technology can recognise problems, identify emergencies, and see different patterns that might be safety critical, as well as improve awareness in the system. Grabowski and Sanborn (2003) also identified differences between the users, depending on their earlier experiences of technology and computers. The authors claim that operators might be conservative in their work habits and they are often suspicious of new technology. The authors also mention how technology can have a negative influence on operators. The result of their study showed that the operator used technology more during periods of high stress, and the operators were relying on the technology. Even if the operators relied on the technology, it did not enhance their performance in high stress situations. The performance in these situations was not significantly improved, the only improvement was registered during low stress periods. The reason, Grabowski and Sanborn (2003), suggest for these findings are that the performance of technology use depends on how related, familiar, confident, and satisfied the operator is with the technology. Canos, Alonso and Jaén (2004) claim that organisations offering public transport need to have an available security plan. These plans are normally text documents but the authors suggest a multimedia application with pictures, animations and sound. The aim of using multimedia in a security plan for public transport is that it is easier and quicker to find the right security information. The results after using their application in the metro of Valencia in Spain showed that the response time and human errors among the operators have been extensively reduced (Canos, Alonso & Jaén 2004).


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2.2.4 Stress

According to Kontogiannis (1996) stress has previously been viewed from two different perspectives. From the first, stress has been viewed as a dimension of the workload and has given rise to the expression: A certain amount of stress is good for a person. From the other perspective, stress has been seen as an effect of the individual and how he/she reacts to stress, while the job or organisational factors that may have caused the stress have been ignored. Today stress is defined as a balance between demands and abilities and how a person can cope with them (Kontogiannis 1996). Some factors, such as the personal characteristics (knowledge, attitudes, and behavioural and cognitive skills), environmental constraints (job requirements and rules), and social support from the co-workers, have a great influence on that coping (Kontogiannis 1996). Kontogiannis (1996) further states that emergencies and high work demands, does not need to result in a stress situation for the workers. It depends on the confidence the workers have on themselves and their co-workers, on the communication between them, and if they have clear responsibilities and access to reliable information. Wallenius (1996) has found when exposed to a lot of stress the attention is limited, and only the most relevant signals from the environment are noticeable. If the stress is further increased, attention is decreased and so is performance. Exposed to too much stress, leads to rigid and stereotyped thinking, intolerances for contradictories, and trouble using abstract thinking. Tasks that need fantasy and creativity become hard to solve but tasks that for example demands physical strain, are easy. Desaulniers (1997) explains the stress effect on performance as an upturned U-shape where performance increases until the optimal level of stress is reached, and thereafter decreases. Wastell and Newman (1996) made a study of the implementation of a computer based control system in an ambulance service and compared it with an old paper-based system. They found that with the computer-based control system both the systolic blood pressure and the operators feeling of anxiety during peak workloads decreased. The conclusion drawn was that the computer-based control system increased the operator performance and decreased the stress level. Desaulniers (1997) claims that stress in a control room occurs when an operator experiences an imbalance between what a situation requires and what the operator is able to handle. Further causes of stress are for example environmental factors (such as high temperature, noises, and a crowded workplace) but also a too high


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workload, competing goals, performance anxiety, and uncertainty. Desaulniers (1997) states four categories of cognitive impairments as effects from stress: narrowing and shift in focus of attention; reduced working memory capacity; time pressure effects; and impaired crew communication patterns. All further described below.

Narrowing and shift in focus of attention

According to Desaulniers (1997) the operator’s attention becomes more narrowly focused during stress. The cues central to the task get a lot of attention while the cues in the periphery easily are forgotten. Therefore, the operator performance decreases when multiple tasks need to be performed at the same time or when multiple sources of information must be considered to make a decision.

Reduced working memory capacity

One example of using the working memory, stated by Desaulniers (1997), is when an operator must remember a telephone number he/she has read until it is dialled. Stress affects the working memory and therefore decreases performance dependent on working memory capacity.

Time pressure effects

During stress, decisions tend to be made more quickly, as if under time pressure (Desaulniers 1997). This affects the decision accuracy and tasks that require precision and systematic analyses become hard to perform.

Impaired crew communication patterns

According to Desaulniers (1997) work teams could fail to work appropriate during stress. The consequences will be that decisions that must be made by many operators together will be hard to make, and tasks that must be performed by several operators will be hard to coordinate.

Desaulniers (1997) states that a solution for stress reduction could be good and well-designed operating procedures minimising the use of working memory and distributing workload between the team members.


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2.3 Touch screen technology

Many different pointing devices have been created to support the interaction between humans and computers (Bender 1999). These devices are categorized in two ways. On-display versus off-display and direct versus indirect. On-display means that the interaction is located on the computer screen. Devices usable for such interaction are light pens and touch screens. With off-display the interaction is made by devices such as the mouse or a touchpad, and is not located on the computer screen. Direct pointing devices allow the user to interact with the computer in the same plane as the computer screen. Light pens and touch screens where the cursor is located directly beneath the device are two examples of direct devices. Indirect devices are for example the mice where the cursor is offset from the point directly beneath the device and the interaction with the computer is located in some other plane than on the computer screen (Bender 1999).

Bender (1999) claims that although the touch screen is an on-display device it can also be a direct device, which makes it unique, unique also in the manner that the user does not have to manipulate a foreign device. By many researchers (Buxton, Hill, & Rowley 1985; Pickering, 1986; Shneiderman 1993) the touch screen due to its natural mode of interaction, is heralded as a superior pointing device. In literature researchers have several times compared touch screens with other devices. A review of their results follows: Karat, McDonald and Anderson (1986) compared a touch screen, a mouse, and a keyboard. The task was to select items from a menu in a calendar program and a telephone directory. Some tasks involved a typing subtask. Their findings were that the touch screen was the fastest and also the most preferred device in all areas except for typing, where the keyboard was the fastest. Muratore (1987) in Sears and Shneiderman (1989) reviewed results from fourteen studies comparing various cursor control devices. The studies showed that the touch screen was the fastest but the least accurate among the devices. Ahlström and Lenman (1987) found that the touch screen was faster than the mouse but presented a much higher error rate, especially on small screens, when selecting a six-character word from a list of words.


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Ostroff and Shneiderman (1988) compared a touch screen, mouse, number keys and arrow keys for the selection of words from an interactive encyclopaedia. As Ahlström and Lenman (1987) they also found the touch screen being faster than the mouse, but they could not find any significant difference between the error rates. Sears and Shneiderman (1989) compared touch screen and mouse on rectangular targets with different sizes (1, 4, 16, and 32 pixels per side). The result was that the touch screen was faster than the mouse for the targets of 32 and 16 pixels per side. For targets of 4 pixels per side they were equally fast, and for targets of 1 pixel per side the mouse was faster than the touch screen. The remarkable results from Sears’ and Shneiderman’s (1989) study is that the users were able to point at the smallest targets of 1 pixel per side on the touch screen, which speak against the expected poor touch screen resolution. The error rates were equal for the mouse and the touch screen for 32, 16, and 4 pixels per side. Only for the single pixel target the use of the mouse resulted in fewer errors than the use of the touch screen. As documented above, several studies resulted in a high error rate for touch screens. Sears and Shneiderman (1989) proclaim that is because of the difficulty to know exactly where the finger touched the screen, which further could depend on two reasons: The poor touch screen resolution or that several pixels are activated on one touch. According to Albinsson and Zhai (2003) the touch screen quality is getting better with time, which will lead to lower error rates.

2.3.1 Advantages and disadvantages

Touch screens have become very popular in many applications, such as kiosks at airports, shopping malls, amusement parks, home automaton, air-traffic-control, and medical and military systems (Shneiderman 1998, p. 318). Shneiderman (1993) has listed the touch screen advantages and disadvantages as below:

Advantages

· Touching a visual display of choice requires little thinking and is a form of direct manipulation easy to learn.

· Touch screens are the fastest pointing devices. · Touch screens have easier hand-eye coordination than

keyboards or mice.


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· No extra workspace is required as with other pointing devices.

· Touch screens are durable in public access and in high volume usage.

Disadvantages

· User’s hand may obscure the screen. · Screens need to be installed at a lower position and tilted

to reduce arm fatigue. · Some reduction in image brightness may occur. · They cost more than alternative devices.

Shneiderman (1993) also says that some critics suggest smudges on the screen may be a problem, but touch screens does not need cleaning more frequently than standard monitors or mice. One disadvantage beyond Shneidermans list is the trouble of typing (Karat, McDonald & Anderson 1986). No studies have resulted in a revolutionary way of typing on a touch screen, which still is a difficulty that needs to be solved. Albinsson and Zhai (2003, p. 105) further add, “…the human finger as a pointing device has very low “resolution”.”, by which they mean that it is “...difficult to point at targets that are smaller than the finger width.” (Andersson & Zhai 2003, p. 105) They praise the touch screen though, since it is much more robust than free moving input devices such as a mouse and claim this might be one reason why it has become so popular for public applications.

2.3.2 Interaction

The interaction through a touch screen differs from the traditional ways of interacting with a computer. Sears and Shneiderman (1989) have come up with three different selection strategies for interacting with a touch screen. The strategies are called land-on, first-contact, and take-off. The land-on strategy uses the location of the first impact with the screen for the selection. A selection is made only if the target exists at the location of the first impact. The first-contact strategy results in the selection of the first target the finger comes in contact with. The users can therefore move their fingers on the screen until they touch a target. In both of the strategies above the cursor is positioned directly under the finger. In the take-off strategy, the cursor is positioned slightly above the finger so the users can see the exact position of their selection. The users can, as in the first-contact strategy, move their


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fingers on the screen and the selection is not made until they lift their fingers. Therefore users can drag their fingers across the screen to the desirable target and select it by lifting their fingers from the screen (Sears & Shneiderman 1989). The three strategies have been debated and their performance studied by many: Potter, Berman and Shneiderman (1989) in Bender (1995) discovered no differences among the different strategies, except the land-on strategy resulted in more errors than the other two. Shneiderman (1993) proclaimed the take-off strategy is to prefer because of the cursor above the finger. Potter, Weldon and Shneiderman (1988) discovered take-off was the preferred strategy among the users and resulted in fewer errors than the other two. Though, with first-contact the selection took less time. Albinsson and Zhai (2003) invented a couple of new strategies, mostly to improve the selection of small targets. The two strategies that gave the best results were cross-keys and precision-handle. The cross-keys consist of a crosshair with arrows at all four ends and an activation key in the centre. The first tap on the screen activates the arrows and the activation key, so adjustments can be made if needed. One tap on an arrow moves the crosshair in the direction of the arrow. When the crosshair hit the desired position the activation key is tapped. If the crosshair at the first tap is far away from the target, the user can choose to point again to get a better starting point (Albinsson & Zhai 2003). Precision-handle increases the precision by letting any movement made on the handle also move the tip but on a smaller scale (see figure 2.1). As in the cross-keys, tapping the activation key in the centre makes a selection (Albinsson & Zhai 2003).

Figure 2.1 The precision-handle strategy according to Albinsson and Zhai (2003). Any movement made on the handle also move the tip but on a smaller scale.


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Albinsson and Zhais (2003) study showed that on small targets the take-off strategy was slower and resulted in more errors than both precision-handle and cross-keys. When the targets were larger the take-off strategy was faster than the other two, and resulted in the same error rate. Albinsson and Zhai (2003) insist that the best strategy is several strategies. They recommend choosing strategy according to our needs. As in the physical world, we use the hammer to hit a needle, and a screwdriver for the screw. Two further interaction techniques for selecting and manipulating icons are presented by Montaniz and Mack (1991) in Bender (1995). The methods are called the 1-2-3 method and the pause method. The 1-2-3 method works as follows. 1. Touching an icon once to select it. 2. Touching an icon twice to open a window. 3. Touching an icon once, and then touching and dragging the icon on the screen. The pause method consists of a brief touch interpreted as a double-click and a longer touch interpreted as a single click. Studying these two methods with the finger as interaction device, the result was a faster performance by using the pause method than the 1-2-3 method (Montaniz and Mack 1991 in Bender 1995).

2.3.3 Feedback

Every interaction needs feedback for an adequate performance. The feedback can be of several forms but the most common are visual, auditory, and tactile. Bender (1999) is certain the high number of errors and the low data entry speed of touch screens are consequences of the users not getting tactile feedback. He suggests that auditory signals may compensate for that lack and increase touch screen performance. Bender (1999) constructed three studies to evaluate the effect of the duration of auditory feedback and target size on a touch screen. The results were that touch screen performance is better with large than with small targets and error rates with small targets are reduced if auditory feedback is used. The auditory feedback should sound between 50 and 400 ms for the best result (Bender 1999).

2.3.4 Target characteristics

According to Bender (1999) the most important characteristics of a target on a touch screen are size, shape, and location and they can have a great effect on both the speed and accuracy with which users accomplish a task.


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2.3.4.1 Target size

Target size is an important matter for interface designers. They must always weigh a trade-off between performance and aesthetics. For example, they have to choose whether to use small but many targets and risk to hinder the acquisition performance, or to use large but few targets, which might engage acquisition performance but waste space on the screen. Therefore, a lot of research is made in this area (Bender 1999).

Leahy and Hix (1990) compared targets of three different sizes. 7.5 mm2, 12.2 mm2, and 20 mm2. No differences in target acquisition accuracy between the targets were observed and target acquisition speed was not measured.

Danckert and Goodale (2001) found a clear relationship between target size and speed by letting eight subjects point at five different square target sizes with the side lengths of 1.9, 3.7, 7.5, 14.9, and 30 mm. They found that the peak velocity of the movement increased as the target size increased. Sears et al. (1993) in Bender (1999) compared four different target sizes and found that large targets were both more preferred by users and permitted faster performance. The sizes of their targets were 22.7 x 22.7 mm, 11.4 x 11.4 mm, 7.6 x 7.6 mm, and 5.7 x 5.7 mm, and significant differences on speed were observed between all sizes. Wilson, Interrieden and Liu (1999) in Bender (1995) designed four different tasks to compare two different target sizes on touch screens. On all four tasks the large targets of the size 20 x 20 mm performed better and faster than the smaller target size of 14 x 14 mm. Hall et al. (1988) studied the effects of various factors such as accuracy rates as a function of tactual recognition size on touch screen performance. Their results were: as the size of the recognition field increased, the accuracy rate increased, but the maximum possible number of fields on the display decreased. They also found that for targets with the size of 10 x 10 mm the accuracy was 66.7%, and for targets with the size of 26 x 26 mm the accuracy raised to 99, 2%, which was also the size where accuracy was maximised. Two terms used to measure system effectiveness in the relation to the size of the target is movement time and contact time.


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Movement time

Fitt’s Law confirmed that the movement time is inflected by the size of the target. Fitt’s Law (see below) is a measure of movement time dependent on size and distance of targets. Larger targets have a shorter movement time than smaller because the user does not need to hit the exact location to the same degree (Bender 1999). Fitt’s Law: MT = a + b log2 (2A/W) MT = Movement Time a, b = Regression coefficients A = Distance of movement from start to target centre W = Width of the target

Contact Time

Contact time is a function of target width and amplitude. As target width decreases and target amplitude increases, the contact time increases (Bender 1999). Research has shown that contact time depends on visual verification time, motor programming, and movement efficiency (Adam & Paas 1996). Bender (1999) noticed in a study about contact time that people seem to wait for feedback in a larger amount when the targets are small. He claims this depends on the difficulty for the user to know if the exact position were hit or not when the target is small, and therefore is waiting for feedback in a greater amount than for a large target. He also suggests planning a movement to a small target takes more time than to a large target. Further, Adam and Paas (1996) found that people seem to spend much more time in contact with the screen the more difficult a task is. This time depends on the visual verification that the finger has reached the target, and the programming of the movement to the next target, that must be done.

2.3.4.2 Target location

Beringer (1990) in Bender (1999) placed nine targets on different locations on the screen and compared the performance of right-handed and left-handed. Beringer (1990) discovered right-handed users to be quicker and more accurate when the targets were placed in the lower-right part of the screen. The left-handed performed the best when the targets were placed in the lower- left part of the screen.


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The eye’s visual fields can functionally be divided into two areas with specific functions. Po, Fisher and Booth (2004) call them the upper visual field (UVF) and the lower visual field (LVF). UVF is specialized to support perceptual tasks in the distance and LVF to support visually guided motor tasks, such as pointing. Po, Fisher and Booth (2004) have compared the usage of mouse and touch screen for targets in the UVF and LVF. They found that pointing (mouse and touch screen) were faster and more accurate for targets in the LVF. Further they found differences in the visual fields for mouse and touch screen pointing indicating that direct touch interaction performance improved when targets were placed in the LVF. Their results led to the implication that the most frequently selected and most important interactive elements should be located in the lower half of the display. Further, physically direct interaction, such as touch screen pointing, should be preferred over less direct interaction, such as mouse pointing. Another implication is to adopt a strategy of organising an interface for perception in the UVF and interaction in the LVF. However, according to Po et al. (2004) these implications need to be further researched. Danckert and Goodale (2001) found the same results in their study as Po et al. (2004) did. They found that the control of skilled visually guided motor actions is better performed in LVF than in the UVF by letting subjects make pointing movements as fast as possible on targets displayed randomly at the LVF and UVF.

2.3.4.3 Target shape

According to Bender (1999) very little research has been made on the effect of target shape on touch screen performance. He believes touch screens can be very flexible in the target shapes and different shapes can both enhance the appearance of an interface and increase the common identity of a product. One study by Breinholt and Krueger (1996), was made on six different target shapes (see figure 2.2) They found no significant differences between the shapes for target acquisition speed, but they found that shape B produced significantly more errors than the other shapes. Shape B was the only separated shape, but the participants used it as if it was continuous, which produced the errors.


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Figure 2.2 Six different target shapes used in Breinholt and Kreugers (1996) study. Shape B produced more errors than the other shapes.

2.3.5 Different technologies

Before deciding to use a touch screen there are several techniques to consider. Some are more usable in a certain area than others. But in general, they are working the same. Small (2002) has listed five basic elements that make up a complete touch screen system:

· The touch screen itself. · The touch screen interface with a computer whose

display is matched to the touch screen. · A controller drives the touch screen and converts each

touch into X/Y coordinates. · A software driver, which communicates between the

controller card and the computer's operating system. · Application-development software, which enables

developers to build their own applications and/or customize existing touch applications.

Further, Small (2002) discusses some of the different touch screen techniques existing on the market, what they consist of and how they work. Thereafter a list, made by Touchwindow.com (2005), for what areas the different techniques are most suitable is presented (see table 2.1 and 2.2).

Resistive touch screens

According to Small (2002) resistive touch screens are the most popular. They are resistant to contamination and liquids, and are therefore very useful in restaurants, factories and hospitals. Unfortunately resistive touch screens are very sensitive to sharp objects that can damage the resistive layers, and the surface includes only 75% optical transparency. The resistive touch screen consists mainly of a glass panel coated with a transparent layer of indium tin oxide that is conductive and covered by a sheet of plastic. The cover sheet is suspended over the glass by separator dots, each less than one-thousandth of an inch thick (see figure 2.3). When the user touches the touch screen the conductive layer under the plastic sheet contacts the glass panel, and a circuit is created. The controller senses the contact and computes the x and y coordinates of the users touch (Small 2002).


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Figure 2.3 A schematic figure of the resistive touch screen according to Small (2002).

Capacitive touch screens

A capacitive touch screen is based on a clear glass sensor with a conductive coating applied with voltage from the four corners of the screen, creating a uniform field. As soon as a user touches the screen the field is broken and the x and y coordinates for that location are sent to the USB port. The capacitive touch screen can be sealed, which makes it resistant to water, dust, and other grease. This is the reason why it suits well in harsh environments such as gaming, public kiosks, and industrial applications (Small 2002).

Infrared touch screens

Infrared (IR) beams are arranged along x- and y-axes. As the user touches the screen the beams are broken and the coordinates are passed to the computer via IR sensors. The IR beams come from a frame of IR-light-emitting diodes mounted on the display (Small 2002).

Surface acoustic wave touch screens

The surface acoustic wave touch screen can be touched with a non-conductive instrument such as a glove, which is an advantage for usage in factory, food, and hospital environment, where the staff often wear protecting clothing. Surface acoustic wave touch screens consist only of glass and provide the user high image clarity and durability. The glass is complemented with piezoelectric transducers for x- and y-axes. To the transducers a 5MHz burst is sent and then converted to surface acoustic waves. When the user touches the screen a bit of the wave is absorbed and the receiver analyses it and transforms it into x-, y-, and z-coordinates (Small 2002).


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Ultra flexible armoured glass touch screen

According to A D Metro (2005) the ultra flexible armoured glass touch screen is the newest invention. It is based on a durable and flexible glass/polymer laminate. It is ideal in harsh environments because of the non-sensitivity to water, dust, or grease. The finger or any stylus can be used to control it. The screen is also very tolerant to violence and continues to work even when smashed with a hammer.

Touch screen differences

Resistive Capacitive Surface Infrared Ultra

Finger operated x x x x x Stylus operated x x x Gloved hand x x x x Vandal resistant x x Scratch resistant x x x x Abrasion resistant x x x x Dust sensitive x x Humidity sensitive x Water droplets sensitive x x

Moisture sensitive x x Temperature sensitive x Cleaning chemicals sensitive x x

Table 2.1 The most common touch screens and their differences according to Touchwindow.com (2005).

Touch screen applications

Resistive Capacitive Surface Infrared Ultra

Desktop x x x Hospitality x x x x x Kiosks x x x x Medical x x x Gaming x x x x Process control x x x x x Food preparation x x Avionics x x x ATM Machines x x x Pay Phones x x x Military applications x x x Harsh environments x x

Table 2.2 The most common touch screens and their recommended applications according to Touchwindow.com (2005).


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2.3.6 Ergonomics

The touch screen surface is with some distance separated from the surface of the display, which creates a gap between where the user believes the target is, and where it actually is (Bender 1999). Leahy and Hix (1990) made a study to see if an interaction with the touch screen was negatively affected when the user did not stand perpendicular to the screen. They had users standing 20 degrees to the left and 20 degrees to the right of perpendicular, selecting targets, as if they were working together on a task. The results were that the users selected targets less accurately when standing on the sides (both left and right) than when they were standing perpendicular to the screen. Hall, Cunningham, Roache, and Cox (1988) made almost the same study as Leahy and Hix (1990). They had users sitting 21 degrees to each side of the perpendicular. Their results also showed that users selected targets less accurately from the side than perpendicular to the screen. Hall et al. (1988) made an extension to the study and added a display declination of 7, 30 and 45 degrees. They found no significant difference between 7 and 30 degrees, but the performance was significantly better than with 45 degrees declination. Because of the fact that touch screens are unique and both display computer output and user input in the same plane, some problems arise. According to Bender (1999) touch screens cannot be in the same position for both optimal input and optimal output. Therefore Lehman and Sutarno (1996) in Bender (1999) have made a list of guidelines for devices such as touch screens where the user is interacting with the device from a standing position (see figure 2.4). The guidelines follow:

· The display should be positioned directly in front of (perpendicular to) the user.

· The display should be adjustable in height between 1040 mm and 1397 mm from the floor to the centre of the display.

· The display should be reachable within 255 to 460mm.

· There should be no obstacles between the user and the display to hinder operation.

· Specific height, distance, and angle adjustments must be made for individual users.


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· The height of the display should be adjusted so the shoulder angle is no greater than a 30-degree angle from the chest, the neck is not bent more than 15 degrees forward, and the viewing angle is no greater than 30 degrees from eye level.

· The distance of the display should be adjusted so it can be reached with an elbow angle between 90 and 135 degrees.

· The angle of the display should be adjusted so it can be operated with the wrist in a neutral position, all points of interaction can be easily reached, and glare is minimised. (Lehman & Sutarno 1996 in Bender 1999)

Figure 2.4 An illustration of the guidelines stated by Lehman and Sutarno (1996) in Bender (1999).

< 30 degrees

< 30 degrees 90-135 degrees

255 – 460mm

< 15 degrees

1040 – 1397mm

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3 METHOD This section describes different methods and relevant empirical theories chosen for this project. This project is built on four parts (see figure 3.1): a field study with observations and interviews to get to know the workplace and the needs of the operators; a HTA (see section 3.2) to find the exact work routines performed, by whom, and in what order; paper prototyping to illustrate the solutions found and be able to discuss them with the operators; and a final software prototype, which was the goal of this project and master’s thesis. Every part has four phases (see figure 3.1): First theoretical background is stated for the method; second an implementation is performed and documented; third a result is presented; and last the result is analysed. The final prototype is also further evaluated in the final discussion of this paper and a conclusion is made. Figure 3.1 The work process of this project.

Paper prototyping

Method

Implementation

Method

Implementation

Method

Implementation

Method

Implementation

Result Result Result Result

Analysis Analysis Analysis

Discussion and

Conclusion

Final prototype HTA Field study

Analysis

Method

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3.1 Field study

User-centred design begins, according to Barnum (2002, p. 85), with an understanding of the users and the tasks they perform in the specific environment. The important factors to learn more about are: user, task and environment. In field studies you gather data about the users and their behaviour in their workplace. Field studies are related to social science and ethnographic studies but are not as long and intensive, though they can still gather rich data (Barnum 2002, p. 85). According to Preece, Rogers and Sharp (2002, p. 342) field studies are made in a natural setting where the aim is to understand the users and how they use technology. The qualitative methods recommended in field studies are interviews, observations, participant observation and ethnography, and the evaluator can choose between two approaches: to be an outsider or an insider participant (Preece, Rogers & Sharp 2002, p. 342).

3.1.1 Observation

According to Preece, Rogers and Sharp (2002, p. 364) the focus in observational studies lies on observing how people interact with each other, with the technology, and how they act in the environment. Observation as a method is described by Maguire (2001) as a part of the user centred design where an interaction designer understands and specifies the context of use. Maguire (2001) claims the context of use is important to analyse because it includes identifying the users with their goals and requirements. Other conditions such as technical, physical, social, and organisational characteristics are also important to identify, as well as everything affecting the use of the system. According to Maguire (2001) it is important to analyse the existing users especially when developing complex systems, and the author further states:

“The quality of use of a system, including usability and user health and safety, depends on having a very good understanding of the context of use of the system.” (Maguire 2001, p. 594)

Maguire (2001) states that observation as a method can be direct or indirect and both include an observer viewing the users while they are working. In a direct observation the observer is actually present at the workplace where the user performs the tasks, while an indirect observation includes video recording and is therefore observed later. Preece, Rogers and Sharp (2002, p. 361) describe observation as a

Method

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technique to help identifying needs for a new product or system. The authors mention that the advantage is that observing actual work gives insights other techniques would not give. The disadvantages on the other hand are that it is time consuming and involves great quantity of data to structure and analyse. Preece, Rogers and Sharp (2002, p. 360) also state the importance of setting up a goal and questions for the observation, which will work as a framework and help the observers retain focus during the observation.

3.1.2 Interview

According to Preece, Rogers and Sharp (2002, p. 390) there are different kinds of interviews and the one to choose depends on the purpose. If the goal is to gain a first impression, an informal interview is probably most successful. The authors further describe how informal interviews have a couple of predetermined questions and how the interviewer follows interesting directions with further questions. Löwgren and Stolterman (1998, p. 107) claim that interviews are best performed while the participants are working with their daily tasks and the designer is sitting next to them asking about the activities and performances.

3.2 HTA

According to Preece, Rogers and Sharp (2002, p. 231) Hierarchical Task Analysis (HTA) is the most commonly used version of Task Analysis (TA). TA is used to analyse a situation through the questions: What are the goals of the situation, and how are people trying to achieve them? TA is a tool for examining the existing situation, which works as a means for establishing new requirements and new designs. HTA concentrates on the physical and observable situations not related to any particular software or device. The first step is to examine the users’ goals, then to divide the goals into sub goals, and then the sub goals into sub-sub goals and so on. Further, to state how the goals are performed in an actual situation, they are grouped into plans (Preece, Rogers and Sharp 2002, p. 231). The levels of detail to examine a situation, according to Shepherd (1998), depend on what purpose the inspector wants to achieve. If some parts are more important than others a more detailed examination on that part is accurate.

Method

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3.3 Paper prototyping

Barnum (2002, pp. 124-126) describes paper prototyping, as a low-fidelity usability testing that is cheap, fast and easy. Paper prototypes can be developed with sticky notes, colours, and notes etcetera. Testing the paper prototype should include the developer team and the people involved by the product. Löwgren and Stolterman (1998, p. 128) describe how a paper prototype can be used to show interactivity through changing notes and letting the user click the illustrated buttons. According to Barnum (2002, p. 126), the testing process can be very simple performed in the following steps:

1. Decide the problem to be investigated. 2. Create a test scenario. 3. Observe the users performing a task. 4. Interview the users to learn more.

3.4 Final prototype

By developing a software prototype a high-fidelity prototype is created. According to Barnum (2002, p. 132) high-fidelity prototyping is a good means for developers to understand how the users are working with the product and to assure that further decisions are made from the users needs and not from the developers guesses. Barnum (2002, p. 132) also finds high-fidelity prototypes usable because the developer can receive feedback from the users though the product is not fully developed. Feedback such as how the user navigate, understand the terminology and the organisation of tasks and steps, and if the product gives the user enough feedback (Barnum 2002, p. 132).

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4 IMPLEMENTATION This section presents how the different methods in this project, such as field study, HTA, paper prototyping, and final prototype, have been implemented.

4.1 Field study implementation

The operator workplaces at the subway corporation were analysed during three different occasions between September and October in 2005. The first time, observations were made to receive a general overview of the organisation, the workplaces and the systems. The second time consisted of a three days long study, with both observations and interviews, and the time was split evenly for studying the alarm- and traffic centre at the subway corporation. The third time more specific information about different work procedures were gathered, through observations and interviews. The observations and interviews were supported by a framework containing the following categories: workplace, work routines, stress, communication and system (see figure 4.1). The categories were identified through discussing elements to observe and a further description of each category follows.

Workplace

The category workplace consisted of studying the control rooms and questions in focus were: How does the environment look? How do the operators use the workplace?

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Work routines

In this category, the work routines were studied in more detail. The questions in focus were: How is the daily work and the different tasks performed? How are the operators using systems and papers in their daily work? Are there any observations supporting the use of touch screen?

Stress

The level of stress in the control rooms is studied in this category. Questions in focus were: Do the operators seem stressed during certain situations? Are there any stressful incidents or routines and how can they be reduced?

Communication

This category consists of studying how the operators are communicating. Questions in focus for this observation were: How are the social environments in the control rooms and what objects are used for communicating? How are the operators communicating with each other, and with whom are they communicating?

System

In this category, the technology and the different computer systems were studied. Questions in focus were: How are the operators using and interacting with the systems in their daily work? What kind of different systems are used in the control rooms? Are there any results of the field study supporting the use of DSS?

Figure 4.1 The wheel shows the different categories in focus during the observations and interviews at the subway corporation. Safety is placed in the centre since it is the aim of the whole study.

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4.1.1 Observation implementation

Within the field study direct observations were made to identify the use of existing systems and workplaces. Observations were made on an information kiosk, at the Swedish Road Administration, Metro Copenhagen, SOS Alarm, and at the subway corporation. To document the observations, notes and photographs were taken. The purpose was to grasp the overview of the workplaces context, though the goals were slightly different at every observation.

4.1.1.1 Information kiosk

An information kiosk at Gothenburg tourist information was observed to gather information about how existing touch screens are used. In focus for the observation were the graphical interface and the interaction techniques.

4.1.1.2 Swedish Road Administration

At the Swedish Road Administration, the main goal was getting to know the environment, since neither of the observers were familiar with the operator environment. Subgoals were to learn how their system for operating the traffic works, study how the operators interact with the system, and the use of DSS.

4.1.1.3 Metro Copenhagen

Metro Copenhagen is a brand new transport system, supported by the latest technology. The main goal of the observation was to study how a high technology transport system looks and works. The subgoals were to get inspiration, and to study what has been done to enhance safety.

4.1.1.4 SOS Alarm

SOS Alarm is in charge of all alarm centres in Sweden that answer the telephone calls for emergencies and contact the ambulance, police and fire brigade. The goal of the observation was to study how the telephone system for a safety-critical area works and how the graphical interface looks.

4.1.1.5 The subway corporation

The observation at the subway corporation is the most important one. In the beginning, the goal was to get a general overview and a global approach of the whole organisation and to make preparations for coming work. In the next step, the main goal was to study the control rooms at traffic- and alarm centre more carefully and detailed.

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4.1.2 Interview implementation

A set of main questions was made to support the interviews (see appendix 1). The questions were formed within the categories in the framework created for the field studies: workplace, work routines, stress, communication, and system. Notes were taken to document the interviews. The interviews were performed at the subway corporation in the control rooms, which are in the operators’ natural setting. The interviews were performed while the operators’ were working with their daily routines. Seven operators were interviewed at the traffic centre and six operators at the alarm centre. Three managers were interviewed to gather information about the organisation and their experiences.

4.2 HTA implementation

The method of HTA was performed to structure the activities and the routines at the traffic- and alarm centre to be able to structure a DSS. All activities in the traffic- and alarm centre were connected in the HTA, built on the knowledge from the field study and the current emergency plan. The emergency plan contains the activities that must be performed in case of an emergency or accident. What operator who performs the specific activities and in what order is not stated. While structuring the activities in the HTA some parts were uncertain and there was a gap of facts. The actual course of activities during an emergency situation was not obvious. To fill the lack of facts and to proceed in the HTA a specific situation was chosen. The specific situation was a fire alarm, since it is serious and involves most of the operators working. An operator workshop with sticky notes and a cardboard was developed to more easily structure the activities (see figure 4.2). A scenario was created to illustrate the situation for the operator. The scenario described the fire starting in a train positioned in a tunnel between two of the most trafficked stations at the subway, and the driver notices the fire.

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The aim of the workshop was to gather information about the activities, their order, and how they are structured between the working operators. The current activities from the emergency plan and the activities of a fire were written on sticky notes. The sticky notes were written beforehand and a cardboard was used as a surface so the operator could perform the method while working at the workplace. The operator moved the notes in correct order and grouped them into working task areas. During the workshop some activities were taken away from the cardboard and some were added.

Figure 4.2 The design of the HTA workshop.

4.3 Paper prototype implementation

The paper prototype implementation consisted mainly of brainstorming and discussions based on the results from the field study and the HTA. The discussion began globally and ended with more detailed information. First the needs (see section 6.1) of the operators were analysed. Work routines and roles were evaluated and restructured and a preferable workplace design was sketched. Thereafter the activities in the HTA (see section 6.2) were structured and divided into the different roles. The current systems were distributed for each role due to their need of the systems. Further, sketches of the system placement at each workplace were made, considered being displayed on a touch screen. The prototype implementation continued with a careful walkthrough and graphical design of all steps in the DSS. Each step was sketched on a white board and thoroughly discussed.

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A paper prototype (see figure 4.3) was developed to visualise the results and analyses from the field study and the method HTA, to use in a test session. Two operators were chosen to represent all operators. The purpose of the test session was to examine how the operators interact with the prototype, if the graphical interface matches the operator’s mental models, and if the steps in the DSS seem natural for them. Figure 4.3 The paper prototype.

4.4 Final prototype implementation

The final prototype is developed in Macromedia Flash MX according to the needs and solutions (see section 6.1), the results from the HTA analysis and the analysis from the paper prototyping session (see section 6.2). The systems in the prototype are mainly pictures from existing systems at the traffic- and alarm centre. Some of them are manipulated in Adobe Photoshop to better fit the functions and interface of the prototype. The manipulated pictures are not to be seen as recommended interfaces. More careful and detailed studies must be performed to develop usable interfaces. Activities in the DSS are taken from the emergency plan at the subway corporation, and reformulated according to the results from field study, the HTA, and the paper prototyping. The final prototype was developed to suite a fire alarm scenario (see section 5.4). To more easily illustrate the scenario and to intensify the prototype some parts of the prototype contain sound.

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5 RESULTS This section presents the results from the field study, the HTA, the paper prototype, and the final prototype.

5.1 Field study result

The field study result from observations and interviews of the different organisations and the subway corporation are presented in the following text.

5.1.1 Observation result

The results from the observations of the information kiosk, the Swedish Road Administration, Metro Copenhagen, SOS Alarm, and the subway corporation are presented below. The subway corporation results are divided into a traffic centre and an alarm centre and the traffic centre is further divided into traffic management and information.

5.1.1.1 Information kiosk

From the observation at Gothenburg tourist information, results concerning what needs to be considered when developing a touch screen interface were collected. One result was that a graphical interface has to be designed specifically for a touch screen and a traditional interface cannot be transferred to a touch screen interface without redeveloping. Further, menu buttons should be at the bottom or on the side of the screen for not covering the screen with the hand while pointing. It is hard for the user to point at too small targets with the fingers and it might be laborious to hold the hand up in the air for a longer time.

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5.1.1.2 Swedish Road Administration

At the Swedish Road Administration in Gothenburg, the traffic operators survey the traffic from their control room called the Traffic Information Centre (TIC). To survey the traffic the operators use a system called Central Steering System (CSS). The work routines at the TIC consist of controlling the traffic by studying pictures from the video surveillance system, which includes almost every part of the west coast region. In CSS, the traffic operators can operate the traffic and manoeuvre tunnels, gates, fans, pumps, and message screens. The operators observe and notice disturbances in the traffic through the video surveillance system. The video surveillance system can also indicate if there is a traffic jam by automatically showing the current picture on a screen. The video surveillance system is very helpful since the operator can quickly get an overview of the situation by watching the pictures. Using only an alarm would not give the operator as much information as a picture does. In case of an alarm, the CSS provides a DSS to the operator. In the DSS, the activities the operator must perform are preceded systematically. The operator cannot ignore a step but in some cases the activities can be manually performed for example to open up a roadblock when a rescue vehicle is arriving. The TIC in Gothenburg will in a couple of weeks move their office. At the new office, they will have a large screen on the wall showing all pictures from the video surveillance system, instead of having several video screens.

5.1.1.3 Metro Copenhagen

The Metro in Copenhagen is brand new from 2002. The uniqueness of this modern subway is that the trains do not have any drivers, which results in a carefully developed surveillance of the subway. Surveillance of all stations and trains is performed from the traffic centre through a video surveillance system. The control room environment is calm, quiet, and light and contains four different workplaces separated from each other. To darken the environment around the screens and to place them in the right angle the screens are placed in dark boxes. At each workplace, there are approximately ten different screens all manoeuvred with mice.

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The different workplaces are the following:

· Information – An operator in charge of all information such as contact with the travellers on the trains and video surveillance.

· Traffic – An operator in charge of surveillance and operating the traffic.

· Infrastructure – An operator in charge of managing all infrastructure technology such as systems for electricity, lights, ventilation, elevators, and escalators.

· Supervisor – A manager that is in charge and takes all definite decisions.

In case of an emergency the special procedures the operators must follow are available in a printed emergency plan. A computer based DSS is not available.

5.1.1.4 SOS Alarm

At SOS Alarm, the telephone operators use a system called Cord COM, but in 2006 a new developed system called Zenit is to be implemented. The new system will connect to all SOS stations in Sweden, which will make the cooperation between the alarm centres easier. Cord COM is integrated and connected to a large database of addresses and telephone numbers in Sweden. It is also connected to a map system to be able to find places geographically. Every incoming telephone call is followed by a sound in the system to catch the operator’s attention. To answer the telephone call a specially designed keyboard is used. Within the system, there is a built in DSS for the operators. The DSS consists of listed telephone numbers under specific categories of activities and emergencies. To make a telephone call to a number in the DSS the number is marked and thereafter called through clicking a key on the keyboard.

5.1.1.5 The subway corporation

The subway corporation is divided into two control rooms: One where the operators operate the traffic and one where the operators are in charge of the alarms. The two centres are separated from each other in the subway corporation building. In this text, these control rooms are called traffic- and alarm centre.

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Traffic centre

The traffic centre consists of two rooms, separated with a glass wall: one room for the traffic management where the traffic leaders are placed, and one room for the operators in charge of the information. The traffic centre is located in a very old building. The air lacks of oxygen, and it is rather dark and hot with a loud humming sound from the many computers. Several old systems not used are still present, which makes the traffic centre even more cramped. The operators at the traffic centre are working in teams, which means that the same groups of operators are always working together. Every team consists of six operators that each has a slightly different expert area. The teams are organised in such a way that the operators’ expert areas complement each other. One of the six operators works as a team leader. The team leader has more responsibility than the other operators and is making the final decisions in alarm situations. The traffic centre has documents containing routines that the operators have to follow. Those documents are collected and called the emergency plan. Every year the security department at the subway corporation updates the routines and the operators need to practice them. The routines can be found on the intranet but are also available printed in a folder. The routines are a support for the operators so they know what to do and who to call in case of an emergency. They follow the routines carefully and do exactly what they say. Serious accidents are rather uncommon but smoke development has happened several times. This has given the operators much training and therefore the traffic centre handles this situation very fast.

Traffic management

The traffic management consists of three workplaces for the traffic leaders: west, central, and east. West and east are managing each part of the subway system while the central workplace functions as an overlap between the other two. The operator at each workplace only has the authority to manage the traffic at their part of the subway system. The traffic leaders at west and east have two computer screens that display the subway system, while the central part has four. The following systems are available at the traffic management:

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Subway system

The subway system is light grey and each train has a number and a colour, which depends on if the train is delayed (yellow) or if it has some sort of service code (red). The traffic leaders always survey the subway system. They track each train that comes into their part of the subway system and follow them until they drive to another part. The traffic leaders also have radio contact with the train drivers to assist them if they need help.

Radio system

The radio system, through which the traffic leaders can communicate with the train drivers and the radio cars, is digital and displayed on two screens placed between the three traffic leaders. The traffic leaders use headsets to hear all communication that takes place among the train drivers. They hear all the communication at the same time, but they are only talking with the ones in their part of the subway system. In the radio system there is a button that the traffic operator has to press to be able to talk to the train driver. Between the workplaces west and central, there is also an analogue system for radio contact. This system is not used very often, only to contact the trains driving on a part of the subway system not visible on the screen.

Large subway system

To get a better view of the subway system a large screen is placed in front of the traffic leaders. This screen consists of one digital and one analogue part and displays the whole subway system. The analogue part is to be replaced so the whole system will be digital.

Telephones

Between each workplace, a regular telephone is placed. There is also a red alarm telephone connected to the police, the fire brigade, and the ambulance. The alarm telephone is also connected to a red lamp in the ceiling that twinkles when this telephone is ringing. In the ceiling, there is a strip of wood on which papers with listed telephone numbers are attached. The lists work as a support to find numbers fast in case of an emergency. Once during the observation an information operator walked to the front room where the traffic leaders operate the traffic, equipped with pen and paper to write down a telephone number from one of the paper lists, and then walked back to the information section.

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Video surveillance system

Five screens are placed on top of the large subway system. The screens display the video surveillance from the subway station where the train drivers are changing shifts. The traffic operators can therefore control that the new train driver is on time and ready to take over.

Command based system

To the left of the workplace west there is a second system for operating the subway system. To interact with this system commands are written. The system is old and not all operators are using it because they cannot remember the commands but they are not removing it since certain functions are easier to perform in this system than in the newer system.

Alarm notification

To notify the operators of an alarm, lights in the ceiling are twinkling. When a train driver presses the emergency button, a loud sound can be heard at the traffic centre.

Paper based systems

During some activities the operators take notes on paper. For example to update the train stems, change the schedule for the train drivers, and backup information.

Information

The operators at the information and the traffic management are often talking to each other. Sometimes they have to walk over to each other because of the glass wall that separates them. The information also consists of three workplaces: one in front of a speaker system, another in front of a log system, and a third for the team leader. The following systems are available at the information:

Speaker system

The speaker system is used to notify the travellers at the different stations about information such as traffic delays. The system is displayed on three different screens and a touch screen interface is used to manoeuvre it. Each station has its own button. To inform the travellers the operator clicks the current station buttons and speaks the message in a microphone directly to the stations. Sometimes the traffic leaders write messages to the information operators on sticky notes, about what to inform the travellers, and attach them to the glass wall.

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Subway system

The operators at the information have two screens each to display the subway system. They are only using it to find out how much delayed the trains are, to be able to inform the travellers.

Log system

Everything that happens related to the subway system must be logged. The subway system actually has a built in log but it produces too much information, which makes it impossible to get statistics from. Therefore, another log system that is very time consuming for the operators is used. During the observation, smoke was coming from a train and the traffic centre had to evacuate it. Two hours after the evacuation the operator at the information was still logging the event.

Power system

In case of an accident, the power must be disconnected at the current part of the subway system. This action has to be done very fast. The power system is very slow and the operators are not satisfied with it. The system is also used during maintenance of the subway system. Nobody can be on the subway rails if the power is on. Each time service people are working on the subway rails they have to call the information to make sure the power is disconnected. To be sure nobody connects the power again the operators write a log on paper over which people that are on the subway rails and for how long. The placement of the power system seems to be bad since no operator has fast access to it and the traffic leaders cannot handle the power system and talk in the radio system at the same time.

Telephones

One telephone is placed close to the log system. No emergency calls are coming to this telephone. Another telephone is placed next to the power system so the traffic leader can disconnect the power and talk over the telephone at the same time.

Infrastructure system

At the traffic centre, the infrastructure system (for further description see alarm centre below) is used only to switch on or off the lights in the tunnels.


The video surveillance system is the same system used at the alarm centre but the information does not use it very often.

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Radio system

One radio system is placed at the information so the operators can take part of the communication between the traffic leaders and the train drivers. Although, they can only listen on a low volume, otherwise the traffic leaders will be disturbed from hearing their own voice.

Text information system

The text information system is used for writing text messages to inform the travellers at the stations. The text messages consist mainly of a timetable that runs automatically, but the system also gives the operators the ability to write alert messages about evacuations and accidents.

Alarm centre

Only one operator works at the alarm centre and the workplace consists of ten different screens, six keyboards and six mice. The routines during the day consist of answering the telephone when people, radio stations, and newspapers call to ask why a train is late, or if there has been an accident. Information about delayed trains are e-mailed to different organisations and updated on different web pages and alarms from the infrastructure are also being taken cared of. The work at the alarm centre is most stressful in the morning. At night, the work routines consist mainly of video surveillance. The following systems are available at the alarm centre:

Infrastructure system

The infrastructure system is used for operating the infrastructure such as tunnel lights, fans, pumps, and detecting alarms for fire or movement etcetera. For each alarm the system creates statistics. There are two screens showing the infrastructure system. When service people are working with the infrastructure, they have to notify the alarm centre and make them aware that some alarms might be activated. When an alarm is activated from the system the operator hears a sound.


Four screens at the alarm centre are used for video surveillance. One part of the system is analogue and is displayed on one screen, and the other is digital and is displayed on three. The digital system provides the operator with several small pictures on each screen. If the pictures are maximised the quality becomes bad and it is hard to see anything. The analogue system is connected to six TV monitors mounted on the wall.

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Log system

The log system is the same system as the one used at the traffic centre. It is used for registering all relevant events, for example every telephone call that has been made during an accident. The logged events are used for statistics. If the operators at the traffic centre already have logged an event, the alarm operators can add information about their actions during the event.

Subway system

The subway system in the alarm centre is only used to survey how late the trains are, and if they are, the alarm operator puts up the information on the Internet.

Telephones

There are five stationary telephones. Three of them are directly connected with alarm telephones at the stations, in the tunnels, and in the elevators. To know which telephone numbers to call the operator uses printed number lists. In case of an accident the operator has a paper mounted on the wall containing a list of numbers presented in a specific order.

Paper based work

There are several documents on the desk and papers are used for taking notes while working. For example, while talking over the telephone the operator takes notes on paper to remember important information that later must be written in the log system. Paper based work is also used for information about train departures, telephone lists and alarm lists.

5.1.2 Interview result

The following text presents the result from the interviews with managers and operators from the subway corporation.

5.1.2.1 Interview with managers

The results from interviews with the managers at the traffic- and alarm centre, presented in the five categories (see section 4.1), follow:

Workplace

One of the managers says that the organisation with the traffic- and alarm centre has been changing and growing over the past two years. The operators are reflecting a lot, are often coming with their points of view, and are very self critical. The manager also mentions how frustrated the operators become when for example the alarms are not working properly.

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Work routines

All of the managers think the safety is well developed at the traffic- and alarm centre. One of the managers says that the focus for the centres is safety, and all operators know the safety procedures by heart. Another one of the manager’s mentions that some of the procedures for the centres are not documented and an operator handbook are on its way to be developed. The manager also thinks the work routines are too many for the operators.

Stress

The managers mention reducing stress and false alarms as important factors to increase the safety. One of the managers claims that computer supported telephone lists and alarm lists instead of printed telephone lists would be better. Another manager believes that in the future the systems will be more automatic and include support to the user.

Communication

All the interviewed managers say that the contact with the operators is good and well established. Especially the manager who is educating the operators is communicating with them regularly. One manager tells that the teams have frequent meetings with or without the managers to optimize the work routines.

System

One of the managers claims that it is important that most of the technology involved in the systems should be used. For example, the current pictures from the video surveillance system could automatically pop up if there is an alarm. In case of a new control room the manager hopes everything would be well planned and developed so every system has a specific place. Another manager says that the requirements for the centres are increasing, but it is hard to fulfill all of them.

5.1.2.2 Interview with operators at the traffic centre

The results from interviews with the operators at the traffic centre, presented in the five categories (see section 4.1), follow:

Workplace

One operator explains that the sounds from all computers and systems are annoying and some of the operators have made complaints about headache. Two operators find that the computer screens, behind the glass wall at the information, are placed too high and are blocking the sight to the large subway system. All the operators in the traffic centre want desks adjustable in height.

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Work routines

One operator wants more specific work routines for each person in the team, and adjusted workplaces for each role. When working at the traffic centre you have to be very alert and focused all the time, one operator explains. If you are not alert, it takes too much time to react in case of an emergency. Several operators are convinced that pauses during the shift would result in a more focused and alert operator. One operator says that it is not hard to know what to do. Everything is routine and many activities are performed automatically. Another operator finds it annoying that everything must be logged and documented, especially during a stressful situation.

Stress

Two operators explain that you have to be durable to stress when working at the traffic centre. During each shift there is always at least one moment when you are exposed to a lot of stress. The operators explain that there are many procedures to take care of at the same time. Several operators have the experience of the work being extra stressful when they were new at the workplace or had been away for a while. Most of the operators have felt insecure about what to do in an alarm situation. Often they discuss with the other operators and together they find a solution. During an alarm situation, they help each other for example by one reading the manual and one handling the radio contact. Sometimes they check the emergency plan after an accident to make sure they have handled the situation right.

Communication

The traffic leaders are talking a lot with the train drivers through the radio, and with each other. They are also often talking to the operators at the information and they have decided to try to call each other on the telephone instead of talking, to eliminate the high volume at the traffic centre. Two operators say the volume in the traffic centre is too loud, which makes it hard to work. The operators at the information find it hard to communicate with the traffic leaders because they never know whether they are talking over the radio system or not.

System

All the interviewed operators claim that the infrastructure is very torn and old. This results in several alarms that the traffic centre cannot be blamed for. All operators say that the infrastructure system delivers too many alarms, and they do not respond to them all since most of them do not concern the traffic centre.

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Most of the operators like to interact with the touch screen and can see this technique to be used for other systems. The operators find the touch screen easier and quicker to use compared to using a mouse but one operator says that if the hands are dry the screen must be pressed several times to be activated. One of the operators explains that the difference between the old and the new systems is that the newer contains more automation. Many operators find the systems to have good functionality, with some complaints though. Two operators complain about the impossibility to talk to the train drivers at the same time as handling the power system or the infrastructure system. Several operators think that some systems have a bad placement, such as the infrastructure system and the power system, which are both placed at the information part but are mainly used by the traffic leaders at the traffic management. Some operators also find it hard to manipulate two mice, the telephone, and the radio system at the same time. One operator does not like when he/she must shift between using mouse and keyboard all the time. Another says that it is easy to take the wrong mouse in a stressed situation. Two operators have the attitude that some things you just have to learn, and you must have a simultaneous capacity to work at the traffic centre. One operator finds the subway system to have good usability but wants to get a better overview of the system. Another operator finds it hard to search for telephone numbers at the list in the ceiling since the numbers are hard to see. The operator would rather have had the numbers programmed in the telephone or in another system.

5.1.2.3 Interview with operators at the alarm centre

The results from interviews with the operators at the alarm centre, presented in the five categories (see section 4.1), follow:

Workplace

Some of the alarm operators think that the design of the workplace is good, and one of them mentions how he/she have been involved in the design. One operator mentions that he/she has to move around a lot to be able to see all the systems. Another thinks that there are too many screens on the workplace but guesses that there is no solution to change this. One operator says that a large screen on the wall for video surveillance and headsets for talking over the telephone would be helpful to have in the future.

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One operator does not like how the systems are placed at the desk and says that the video surveillance system could be placed better on the wall, to reduce the systems on the desk. The operator also thinks that the screens should be higher instead of wider, as they are today. The operator further suggests two work areas with two different workplaces, involving separate work tasks. All of the operators declare that they do not like working alone and not be able to have a break during the eight-hour work shift. If a new control room is developed, the workplaces for alarm and traffic should be at the same place.

Work routines

One of the alarm operators mentions that he/she has been away from the work, and was insecure in the beginning when getting back to work. According to one operator the most time-consuming work routine is to keep log in the log system, and to talk to people over the telephone. Another of the operators mentions e-mailing as a time consuming task.

Communication

Several operators say that the communication between the traffic- and alarm centre is too complicated since they have to call each other on the telephone. The alarm operators think that it would be good for the communication if the centres were common, since they sometimes wants to ask the traffic leader about work situations.

Stress

All operators think that the work is very stressful in case of an emergency, especially since they are working alone and do not have support from anyone else. It is stressful because everything happens at the same time and the work has to be done fast. One operator says that the routines and the alarm telephone list for whom to call, stapled on the wall, are very helpful during a stress situation. Most of the operators at the alarm centre refer to the emergency plan, when asked what to do in an alarm situation.

Two operators tell about all the work tasks during a stressful situation, and tell how hard it can be to remember all things to do. The operators also describe the alarm situation as particular hectic when they have to move between different systems to do a number of different things. One of the operators mentions how the telephones are ringing all the time during an alarm situation.

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System

One of the operators thinks the systems are easy to use, but they took a while to learn. In the beginning, the operator felt insecure but now he/she controls them.

All operators claim that the pictures from the video surveillance system are too small to show relevant information. One of the operators says that he/she wants quite large screens (70 inches) in front of the operators’ workplaces to get a better overview. Two of the operators mention that the negative aspect with the infrastructure system is that the alarm list contains many alarms, and several of them are false alarms.

5.2 HTA result

The HTA resulted in a figure with a main goal, subgoals, and sub-subgoals (see figure 5.1). The main goal at the traffic- and alarm centre in case of a fire is to solve the fire emergency and as soon as possible get the traffic back to normal. The sub-subgoals are mainly the activities from the emergency plan, but now structured due to the work roles in the control room. There are four working roles active during the fire emergency: traffic leader, team leader, information operator, and surveillance operator. Each work role has a task to fulfill, which in the HTA is stated as the subgoals beneath the main goal. The traffic leaders goal is to stop the trains, the team leaders is to send for help organisations, the information operator informs travellers, and the surveillance operators contacts concerned organisations (see figure 5.1).

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Figure 5.1 Activities during a fire alarm, structured for each work role.

Solve the fire

emergency

Traffic leader Stop trains

Team leader Send for help organisations

Information Inform

travellers

Surveillance Contact info

organisations

Inform everyone at the traffic

centre about the alarm

Confirm the alarm

Stop all trains from behind

Stop trains from both directions

Contact the train driver

Switch on the lights in the

tunnel

Contact the radio car

Disconnect the power

Call the internal organisations

Call the fire brigade

Evacuate the train

Call the board of accident

investigation

Call the railway organisation

Call the accident board

Call the section leader

Call the local crisis centre

Call the police

Call the ambulance

Call the alarm centre


Supervise the fire brigade

Inform the travellers at the

stations through the speakers


stations through the information

signs

Log the activities

Call the information

manager

Call the support functions

Call the station security guard

Call the involved

organisations


Direct the video surveillance

system

Call the traffic information organisation

Call the customer

centre

Update the information

on the Internet

Call the elevator company

Keep the traffic going

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5.3 Paper prototype result

The result of user testing the paper prototype showed that there could be problems with the communication between the traffic leader and the operator at the infrastructure. These two operators need to have a close communication when for example disconnecting the power and using the power system. Sometimes there is not one single way to disconnect the power on the subway rails and the operators need to change and try new ways all the time. This can be hard to adjust in a DSS system. The test also showed that there is a need to decrease the activities for the team leader during an emergency since he/she is in charge of the whole situation and must have a general view over the emergency. If the team leader has to call and inform several instances, this can be hard. To reduce these activities for the traffic leader a suggestion was to let the infrastructure operator perform them instead. The information at the traffic centre has also had problems with too many telephone calls. They have to inform the travellers at the stations and at the same time make several telephone calls. The telephone calls are very time consuming and the traffic information becomes poor. All operators involved in the test want to be able to see which instances that have been informed and think that a common log available in the DSS could be useful. The operators also want to see how far all other operators have come in the alarm process, as well as seeing relevant pictures from the video surveillance system on a large screen.

5.4 Final prototype result

The goal of this project was to create a software prototype illustrating a workplace designed after the needs at the traffic- and alarm centre at the subway corporation. To best demonstrate the prototype it is built upon a scenario.

Scenario

A fire is detected on train 504 on subway line number two. When the train driver notices the fire, the train is positioned between two stations. The train driver contacts the traffic leader through the radio system at the east part of the traffic management.

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DSS

On the right side of the screen, every operator finds the DSS. Behind the DSS there is a telephone system reachable through a flap, labelled “Telephone”, at the lower right corner of the screen. The DSS contains buttons with the activities the operator must perform in an alarm situation. The DSS functions as a support to the operator so that he/she always knows what to do, in what order, and when. To show the operator what to do next a red frame is visible around the button. Some activities are the same in all operators DSS and therefore described below.

DSS setup and cancel

A DSS can only be setup from two roles at the workplace: traffic leader and infrastructure. The traffic leader setup a DSS after talking to the train drivers through the radio system and the infrastructure after getting an alarm from the infrastructure system. The traffic leader starting the DSS is also the only one that can cancel the DSS for the other operators.

Make a telephone call

Several activities in the DSS are about making a telephone call. The buttons for these activities have a different look to support the operator when making a telephone call (see figure 5.2). The operator gets a number to call but is able to change it by pressing the button labelled “New no”. A change of number can be needed if the first telephone call is not getting through. To make the telephone call the operator only presses the button and the telephone system connects to the DSS. To hang up, the button with the red telephone receiver is pressed.

Figure 5.2 The button for making a telephone call.

Normalisation

Every workplace has a button labelled “Normalisation” last in the DSS. This button closes the DSS and starts a new to normalise the alarm situation. Every activity at every workplace does not need do be normalised, though in some cases it might be more important. For example when connecting the power in the subway system again the operator might need support. The normalisation support is not implemented in the prototype and pressing the button only closes the DSS and ends the alarm situation.

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Log system

When an activity in the DSS is performed, it is automatically logged in the log system. Further information, for example, at which stations the trains are stopped or at which part of the subway system the power is disconnected, are also logged. In the log system the operator has the possibility to see the log of the other operators DSS and how far they have come in the alarm process.

Operator centre

The prototype involves an overall solution where the aim is that all operators have a 50 inches touch screen at their workplace. The screen contains all systems each operator needs to perform their work routines. The operator uses the systems by clicking on the screen with the fingers.

Large screen solution

The prototype includes a large screen to give all the operators a better overview of the traffic situation (see figure 5.3). The screen is planned to show one part for the traffic leaders with an overview of their subway system and one part with video surveillance pictures for the operators at surveillance and information. In the middle, there is a common part where information concerning all operators can be placed. In an alarm situation, a status report from all operators’ DSS can be presented here.

Placement of work roles

It is important to place the operators to benefit communication and cooperation between them. The prototype includes a suggested placement for the different work roles, (see figure 5.3). The traffic leaders are placed in front of the large screen and the overview of the subway system. The team leader, who is in charge of all operators in the centre, is placed behind the traffic leaders. This placement gives the team leader a general view of the whole centre and the large screen. The operator at infrastructure is placed beside the team leader, since they need to communicate and discuss the work. The team leader can therefore also control and help the operator at infrastructure with the power system. The operator at information is placed beside the operator at video surveillance. These two operators are communicating a lot by talking over the telephone and the speaker system and are therefore placed away from the traffic leaders to not disturb them. These operators are also placed in front of the video surveillance displayed on the large screen.

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Figure 5.3 Overview of the centre with a large screen and the suggested placement of the different operator roles.

5.4.1 Traffic leader

Area of responsibility

The traffic leader operates the traffic, surveys the subway system, and communicates frequently with the train drivers.

System

The systems the traffic leaders need to perform their work are the subway system and the radio system. The traffic leader can survey the whole area of east, west, or centre at the same time.

DSS

In the scenario the traffic leaders are in charge of starting the DSS for all other operators. He/she starts the DSS through clicking the train on the subway system. A menu appears and the operator can choose what kind of alarm situation it is (see figure 5.4). The grouping of alarm situations are the same as the one in the emergency plan used by the subway corporation. When the traffic leader starts the DSS it appears on the right side of the screen. An alarm sound identifies that the DSS is started. A graphical symbol with a warning triangle and a fire indicates where the alarm started in the subway system. The first acitivity in the traffic leaders DSS is to stop trains.

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Stop trains

When the traffic leader clicks this button in the DSS, a part of the rail in the subway system is automatically suggested to be stopped and the traffic lights in the system blink red. A box containing the buttons “accept” and “cancel” gives the operator a chance to either change the automatic suggestion, accept it, or cancel (see figure 5.5). When the suggestion is accepted the traffic lights become red and the trains on the subway rail are stopped.

Contact radio car

In this activity the radio system and the communication box for contacting the radio car become active. The DSS automatically chooses the radio car closest to the alarm place. The traffic leader can then communicate with the guard in the radio car and inform about the alarm situation. In the prototype a sound example of the dialogue can be heard.

Activate disconnecting the power at infrastructure

By pressing this button the traffic leader inform the operator at infrastructure that it is time to disconnect the power at the subway rail. Since disconnecting the power is a very crucial and important part during an alarm situation the communication between traffic leader and operator at infrastructure becomes very important. Through the DSS the traffic leader gives the operator “green light” when this activity can be performed. The traffic leader clicks the button “disconnect power at infrastructure” and a box with “accept” and “cancel” appears. When the traffic leader accepts, the button “disconnect power at infrastructure” becomes active and the traffic leader waits until the operator at infrastructure has disconnected the power. A confirmation text is shown in the box and the subway system becomes red on the current subway rail, to assure the traffic leader the activity is performed.

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Figure 5.4 The figure shows the subway system at the top, and the radio system at the bottom. In the subway system the menu for starting up the DSS shows.

Figure 5.5 The activity “stop trains” is activated from the DSS.

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5.4.2 Infrastructure


The operator at infrastructure is responsible of managing the infrastructure, such as alarms and repair.

System

The systems available for the infrastructure operator are the infrastructure system, the power system, the video surveillance system, and the log system with Internet. In the prototype the infrastructure system is integrated with the power system. In the video surveillance system the operator surveys the places where alarms are activated.

Figure 5.6 The operator at infrastructure has disconnected the power.

DSS

When the DSS is started pictures from the stations and the subway rail affected by the fire are automatically shown in the video surveillance system. First when the traffic leader presses the button “Disconnect the power at infrastructure”, the button labelled “Disconnect the power” becomes active for the operator at infrastructure.


When the button is pressed the power system is shown in the infrastructure system and an automatic suggestion of which part of the subway rail that should be powerless is shown in the system. A pop-up box asks the operator whether he/she accepts the suggestion or not. Accepting disconnects the power on the suggested part of the subway rail. Not accepting makes the suggestion disappear and the operator

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can choose another part of the subway rail. Are there only small changes that the operator wants to change within the suggestion this can be done before pressing the accept button. To show all operators that the power is disconnected, a symbol is shown and the affected part of the subway rail turns red in the subway system, the power system and on the large screen (see figure 5.6).

Switch on the lights in the tunnel

When the button is pressed the tunnel lights system is shown in the infrastructure system and the system gives the operator a suggestion on which part to switch on the lights. Accepting the suggestion switches the lights on and it is shown in the infrastructure system with an orange visualisation on the subway rail. Since the tunnel lights are not as important and safety critical as the power it is not shown in the subway system.

Telephone calls

The operator at infrastructure calls a couple of instances tied to infrastructure questions to inform about the alarm situation.

Escalator

When the operator presses the button labelled “Escalator”, pictures of the escalators at the stations affected by the fire are shown in the video surveillance system. One feature could be that the operator is able to manipulate the escalators from the traffic centre, but is not implemented in the prototype.

Elevator

When the operator presses the button labelled “Elevator”, pictures of the elevators at the stations affected by the fire are shown in the video surveillance system. Elevators could also be manipulated from the traffic centre, but is not implemented in the prototype.

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5.4.3 Team leader


The team leader is responsible for the overall work situation in a team of six operators, and for taking the final decisions in alarm situations.

System

The team leader has the subway system, the log system and Internet available on his/her screen (see figure 5.7).

DSS

Since the team leader is responsible during an alarm situation it is important that the team leader is available and has time to grasp the overall situation to make the right decisions. To give the team leader time for this the activities in the DSS are few.

Triple alarm

The first activity in the DSS for the team leader is to call and carry out a triple alarm, which includes calling the fire brigade, who alarms the police and ambulance.

Call the board of accident investigation

The team leader calls the board of accident investigation and informs the organisation about the alarm situation.

Figure 5.7 The placement of the systems and the DSS for the traffic leader.

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5.4.4 Surveillance


The operator at surveillance has the responsibility of the video surveillance and to inform different instances during an alarm situation.

System

The operator at surveillance has the video surveillance system and the log system with Internet available on the screen (see figure 5.8). The operator has the authority to decide what pictures should be displayed on the large screen.

DSS

When the DSS is started pictures from the stations and the subway rail affected by the fire are automatically shown in the video surveillance system.

Telephone calls

The operator at surveillance calls the local head of information, guards, kiosks, and stores at the stations affected by the alarm to inform about the situation. Also the customer service centres are called so they can spread the information about the alarm situation.

Figure 5.8 The workplace for the operator at the surveillance.

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5.4.5 Information


The operator in charge of information is responsible for informing the travellers through speakers and information signs at the stations.

System

The available systems the operator at information has on the screen are the traveller information system, the speaker system, the log system and Internet (see figure 5.9).

DSS

The operator at the information workplace has mainly one activity:

Inform travellers

The operator at information clicks the button ”Inform travellers” and the DSS automatically gives a suggestion for which stations chosen and which messages that should be used (see figure 5.9). The two former systems used to inform travellers are in the prototype integrated with each other. Both text- and voice messages can be sent to the stations at the same time. The operator can choose to start, change, or cancel the suggested messages. When the operator clicks on start the messages enters the stations and in the prototype a voice sound confirms the activity.

Figure 5.9 The appearance of the screen for the operator at information. The speaker system integrated with the text information system gives a suggestion of messages to be sent to the stations concerned by the alarm.

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6 ANALYSES In this section the results from the field study, the HTA, the paper prototype, and the final prototype of this project, are analysed.

6.1 Analysis of field study

The field study result has been analysed and a set of needs have been stated in the five different categories: workplace, work routines, stress, communication, and system (see section 4.1).

6.1.1 Workplace

Every operator likes the work climate and seems to enjoy the work, though there is a need for:

Increasing the physical space

Every operator thinks there are too many systems and screens, and there is not enough space for all operators to work at the same time.

Adjustable workplaces

All operators want workplaces adjustable in height.

A better view to the large subway system

Several operators at the traffic centre have made complaints about the screens at the information and the glass wall both blocking the sight to the large subway system.

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A better system placement

Several operators think that some systems have a bad placement and should be placed close to the operators using them the most. Two examples are the infrastructure system and the power system, which both are placed at the information section of the traffic centre but are used mostly by the traffic leaders at the traffic management.

Fewer objects at the workplace

Several operators think the mice, telephones, keyboards, and flexes at the workplace are too many. At the alarm centre they have marked the mice with which system they belong to, to prevent using the wrong one.

Decreasing the distance between the systems

Some operators find it hard to get an overview when the distance between the systems is too long. One example at the alarm centre, is the distance between the infrastructure system and the telephones, which makes it impossible to manoeuvre the infrastructure system and talk over the telephone at the same time.

A calm and quiet workplace

Several computers, screens, radios, alarms, and people in the same room at the same time, increases the volume at the workplace.

6.1.2 Work routines

The operators like working in teams. They feel like they get to know each other better, their qualities, their opinions, and how they are reacting in different situations, though there is a need for:

Simplifying the communication

The communication between the traffic- and alarm centre is regular which becomes a problem since these two centres are separated. To work efficiently and have a good communication between traffic- and alarm centre all operators’ mention that it is necessary to work in the same room.

Support from each other

At the alarm centre, there is a need to discuss with each other and feel support from someone else. All operators in the field study indicated it was a problem to work alone at the alarm centre.

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Eliminating irrelevant work tasks

Some work tasks performed by the operators are irrelevant and take extra time and the operators’ attention. One example is when the operators are taking notes on paper about which people working at the subway infrastructure, and later write the information in the log system.

Facilitating frequent work routines

To facilitate for the operators it is important to make frequent work routines more efficient. Making routines efficient can be done through changing the tasks to be done in fewer steps and with fewer choices. The tasks can be performed quicker with few steps. The work routines that need to be more efficient follow. Video surveillance – The pictures are too small and indistinct and are not giving the operator sufficient information. Write in the log system – To log is very time consuming for the operators, time that can be used more efficiently. Make telephone calls – Calling is another time consuming activity since the operators have to find the right numbers on the printed telephone lists and then manually dial the numbers. Keep track of delays – The operator has to click on the train icon to see information about delays and the colour code that shows when a train is delayed gives the wrong information.

6.1.3 Stress

The operators think that the work is stressful in case of an emergency, but otherwise rather calm. Several operators seem to enjoy the stress when it comes in an acceptable amount, though there is a need for:

Providing a better support for operators feeling insecure

Operators working seldom and operators that have been on the sick list are often feeling insecure of the work routines, which lead to stress.

Providing a continuous support for all operators

The operators are sometimes controlling that they made the right actions by reading the emergency plan afterwards. They need a better support so they can always be sure they did the right thing.

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6.1.4 Communication

One of the most important aspects for a good work in the traffic- and alarm centre is communication. The two centres are placed in different rooms and at different levels in the building. The communication seems to work well, though there is a need for:

Facilitating the communication between each other

The operators at the traffic centre are placed at different parts of the control room and a glass wall is separating them to lower the noise level. The communication between the operator roles is important, though the glass wall makes it complicated.

Improving the radio communication

The radio communication ties the traffic leaders to the workplace. The traffic leader must leave the workplace to disconnect the power during an alarm situation and the communication through the radio system is thereby broken. Therefore, there is a need for the traffic leader to be able to walk away from the workplace without breaking the radio contact.

Simplifying listening to the radio system

The operators, other than the traffic leaders, need to listen to the communication from the radio system. The traffic leaders are disturbed when the other operators listen to the radio communication because of the noise and the echo of their voice.

6.1.5 System

There is a large amount of systems at the traffic- and alarm centre. The operators seem to know how to use them all and they like some systems better than others, though there is a need for:

Larger screens for supervising the video surveillance system

As a result of the small screens too many pictures must fit into the screen and they become too small to show important information. The quality also needs to be improved.

Decreasing the amount of false alarms

False alarms decrease the confidence in the system and when something really happens the operators are not prepared.

Simplifying the interaction between system and operator

The operators have to interact with several things at the same time: mice, telephones, keyboards, and microphones.

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Making a better use of existing systems

There are systems that after some modifications could make other systems unnecessary and thereafter could be eliminated from the centres. One example is the several systems for traveller information that could be integrated and save a lot of effort for the operators. Other systems that could be used more efficient are the log system and the subway system.

Removing old systems

Old systems not used should be removed since they divert the attention of the operators and take unnecessary space at the centres. To create a spacious operator environment, systems without a specific need should be removed.

Simplifying telephone activities

It is very time consuming for the operators to make telephone calls. The operator has to find the numbers on printed telephone lists and dial the long numbers manually. This activity can be very stressful during an emergency and therefore telephone activities need to be simplified. There is also a need for being able to write in the log system at the same time as talking over the telephone. Today the operators are first taking notes on paper to be able to write the information in the system later on.

A better overview of the subway system

The operators do not have a good overview and they must use the mouse and scrollbar to see the different parts of the subway system.

Minimising paper work

Paper work is an unnecessary task taking too much time from the operator. An example of paper work is when the operator is taking notes on paper of which service people working on the subway rails.

Integrating systems

Several systems at the traffic- and alarm centre can be integrated. Some systems even have the same kind of functions, which makes them easier to integrate. System integration can lead to better and more efficient work.

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Solve the fire

emergency

Traffic leader

Stop trains

Team leader

Send for help org.

Info. Inform

travellers

Surveillance Contact info.

organisations

Confirm the alarm

Stop all trains

Switch on the lights

in the tunnel

Contact the

radio car Call the internal

org.

Call the fire-

brigade, ambulance

& police

Call the board of accident investigation

Call the railway

org.

Call the accident

board


Call the local crisis

centre



stations through the speakers


stations through the information

signs

Call the info.

manager

Call the support functions

Call the involved

org.

Call the traffic info.

org.

Call the customer

centre

Infra- Structure Supervise

infrastr.


Check the escalators

Check the elevators

6.2 Analysis of HTA

From the result of the HTA, each step was thoroughly discussed. The focus was on which actions involve the different systems and which actions do not involve any systems at all. Some of the activities were eliminated since they are not actions in any system and therefore not relevant actions to be illustrated in the prototype. The discussion also concerned how the actions should be divided among the different operator roles. Finally, the analyses of the HTA in combination with the result and analysis from the field study resulted in a new operator role in charge of infrastructure. The HTA result was therefore slightly altered (see figure 6.1).

Figure 6.1 The HTA analyses resulted in a new operator role.

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6.3 Analysis of paper prototype

The analyses of the paper prototype test session resulted in some changes before developing the final prototype. The result showed that there might be a problem when the operator at infrastructure is going to disconnect the power. If the team leader should have that activity instead, he/she must have the power system on the screen, which would be a waste of space since the system will only be used for that activity. We decided therefore to let the operator at infrastructure be in charge of disconnecting the power since he/she already is in charge of everything else concerning the power system. The operator at infrastructure will get help though, from the traffic leader, to determine when to disconnect the power. The traffic leader has a much better overview of the situation and knows when the trains are stopped. The communication between the two operators is supported in the DSS. The activities for both team leader and operator at information are minimised according to the results (see section 5.3). The team leader must have time to survey the situation and the operator at information to inform the travellers. Therefore several of their telephone calls are moved to the operator at infrastructure because he/she had not so many time consuming tasks to perform during an emergency. The prototype should also include a large screen where one part that all operators can see shows the log from all operators’ DSS.

6.4 Analysis of final prototype

The analyses of the final prototype consist of solutions connected to the needs from the field study and a user test.

6.4.1 Solutions to the needs

To every analysed need (see section 6.1), a solution describing how the prototype solves the need is presented below.

6.4.1.1 Workplace

Increasing the physical space

To increase the physical space at the workplace all systems the operator needs are placed on one screen. All the other screens could be eliminated and the movement around the workplace will decrease, which will lead to a more spacious workplace.

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Adjustable workplaces

Placing the screen on a desk that is easily adjusted in height and angle will result in a more ergonomic workplace.

A better view to the large subway system

By creating adjustable workplaces for the operators they can easily change their sight to the large subway system themselves.

A better system placement

When all the systems one operator needs are placed on one screen the operator never has to move to reach a system. Both the infrastructure system and the power system are placed in front of the operator at the infrastructure and are used only from this position.

Fewer objects at the workplace

Flexes and keyboards are decreased by only using one screen for each operator, and by using touch screen technology on that screen all mice can be removed. Telephones are also removed and replaced by a telephone system on the screen.

Decreasing the distance between the systems

With a better system placement the distance between the systems is automatically decreased.

A calm and quiet workplace

The operators are given a specific task and a workplace on their own that will make them talk less to each other. The systems are also providing a better support than before, which means that the operators do not need as much support from each other any more. By decreasing the telephone calls to the traffic leaders the workplace will be much calmer and by introducing the telephone system the ringing from the telephones will only be heard in the headset of the operator for whom it is ringing.

6.4.1.2 Work routines

Simplifying the communication

To solve the need a restructuring of the centre is required, the prototype gives a suggestion of how the operators with the different work roles should be placed in the centre to support communication and cooperation (see figure 5.3 in section 5.4).

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Support from each other

To place all operators in a common centre would solve this problem and all operators can cooperate with each other. The developed DSS gives the operator support within the systems and support from other operators might therefore not be as important.

Eliminating irrelevant work tasks

A restructure of the work roles results in an operator responsible for infrastructure, who can log this information immediately in the log system.

Facilitating frequent work routines

Video surveillance – The prototype contains a large screen solution that gives the operator better overview and larger pictures. Write in the log system – The DSS logs all actions activated by the DSS automatically. Make telephone calls – A telephone system helps the operator making telephone calls. Keep track of delays – Adjustments in the subway system is needed to give the operator the right information on the screen.

6.4.1.3 Stress

Providing a better support for operators feeling insecure

The DSS gives the operators support with what activities to perform and in what order, which will decrease stress and uncertainty for the operator. The DSS also handles a proposition of the most suitable solution, which will result in a faster performance of the activities.

Providing a continuous support for all operators

The DSS is present during the entire alarm situation, which gives the operator a continuous support. The operator can feel safe and secure and does not need to check afterwards if the correct decision was made.

6.4.1.4 Communication

Facilitating the communication between each other

To facilitate for the traffic leader the prototype includes a telephone system to make telephone activities more efficient. The telephone activities are also minimised since the operator at infrastructure is in charge of incoming information concerning the infrastructure. The

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need for better communication between traffic leaders and information operators at the traffic centre is then facilitated. The prototype also facilitates the communication since the operators are placed in a way to aid the communication. The DSS in the prototype also includes built in communication between the operators. For example, the traffic leader sends a message through the DSS when it is time to disconnect the power on a subway rail.

Improving the radio communication

The prototype facilitates the communication when an operator in charge of the infrastructure is responsible for disconnecting the power and as a result, the traffic leader does not have to leave the workplace.

Simplifying listening to the radio system

A solution from the prototype is to use the headset for both telephone communication and for listening to the radio communication. This can be a function available in the telephone system and the traffic leader will then not be disturbed by the noise.

6.4.1.5 System

Larger screens for supervising the video surveillance system

By using a large screen to display the pictures from the video surveillance system they can be displayed in a much larger size.

Decreasing the amount of false alarms

By having one operator responsible for infrastructure, only he/she will be exposed to the false alarms. The infrastructure operator also has better knowledge, than the other operators, of the workers on the subway and can therefore easier judge if the alarm is false or not.

Simplifying the interaction between system and operator

By using only one screen and touch screen technology the different interaction techniques are limited and the operators only need to learn one.

Making a better use of existing systems

By integrating the text information system and the speaker system the same information could be spread to the same people at the same time but in two different media (text and sound), which will intensify the information message for the travellers. The log system is integrated with all the other systems and the DSS. When an activity is performed in the DSS it is logged automatically to strain the operator as little as possible.

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The same subway system should be displayed on the large screen and on the workplaces to make it easier for the operator who then only needs to know one system for controlling the subway.

Removing old systems

The prototype includes all the systems needed for the specific work roles and the systems not included in any role can be removed.

Simplifying telephone activities

The prototype includes a telephone system placed at the same position as the DSS. The telephone system is not developed though it is a part of the overall picture of the prototype. The telephone system should include all relevant telephone numbers and is integrated with the DSS that gives the operator the current number for each alarm situation.

A better overview of the subway system

This problem is solved by showing all subway lines (east, west or centre) that each traffic leader is responsible for, at the same time. A large screen also gives the operators a better overview of the whole subway system.

Minimising paper work

In the prototype, the operators can use headsets while they are talking over the telephone and therefore they can write information directly in the systems instead of taking notes on paper.

Integrating systems

Both the DSS and the log are integrated with all systems activated by the DSS. The subway system is integrated with the video surveillance system and pictures of the current location are automatically activated in case of an emergency. The power system is integrated with the infrastructure system since both systems concern infrastructure. The text information system is integrated with the speaker system since both systems are used to inform travellers.

6.4.2 User test

The analysis was made together with operators and managers (hereafter named operators) at the subway corporation and performed as a workshop where the operators could test the prototype and tell their opinions (see figure 6.2). An observation was made at the same time to collect the usability imperfections not uttered. The result and analysis of the workshop follows. After only a short time of testing one of the operators rested the finger on the screen frame. It seemed that he/she did not know where to put

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the hand when he/she did not need to point at anything. Maybe this could be a result of a too large screen, the inexperience of standing work, or the inexperience of working with touch screen interfaces that made the operator uncertain with what parts of the screen that are touchable and not. One operator tried the menu, which becomes active when the train is clicked, several times and seemed to have trouble understanding how it worked. Unfortunately only the scenario path is clickable in the prototype and therefore it is hard to make any clear statements of this observation. Another operator explained how a menu is working, which led to the conclusion that it might be understandable after all. The buttons in the DSS were very easy to press and the operators never missed. The workplace buttons down at the left corner of the screen were also easy to press. The check boxes in the log were much harder to hit and often the wrong box was hit, which resulted in the wrong log displayed. Following the scenario it was easy for the operators to understand what to do and where to click. They noticed the red frames around the active systems and around the buttons. Two operators discussed the log and the DSS and thought they were the best functions developed and implemented in the prototype. They especially liked that the log was automatic. Observations and opinions of the operators gave the impression that the touch screen made the manipulation of the systems easy and fast.

Figure 6.2 The operators are testing the final prototype.

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7 DISCUSSION In this section the method, results, and analyses are discussed and connected to the theoretical background. In the conclusion the research questions are answered and thereafter suggestions about future work are presented.

7.1 Method and implementation

In this project, the area of HCI has been in focus during the whole process. The operators have therefore been central in every part of the prototype development. The prototype has been developed as a solution for the whole environment but mainly as a means to answer the two research questions (see section 1.2). By letting the users be a part of the whole development process we have gathered a lot of information about their needs and opinions, and about changes that should be made. According to Andersson and Sandblad (2003a), a user centred design process should be used to take advantage of the users’ competence when developing operator systems and graphical interfaces. Andersson and Sandblad (2003a) further claim how a user centred design process is iterative and the phases: analyses, design, implementation, and evaluation are repeated until accepted by the users. This project has been iterative through using different methods: field study, HTA, paper prototyping and finally a software prototype was developed. A prototype developed without the users would have resulted in a completely different prototype and might not have been suitable for the users at the subway corporation. As Preece, Rogers, and Sharp

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(2002, p. 4) describe it; the aspect of usability depends on where it is going to be used and by whom. By including the users early in the process, you can be more certain that the result will be appreciated, as also Maguire (2001) claim as an important key principle in a user centred design process.

7.1.1 Field study

The field study of this project consisted of observations and interviews. Both started simultaneously to get to know the environment and the operators, and resulted in general studies that became more detailed at the end. The framework set up according to Preece, Rogers and Sharp (2002) was very useful and made it easier to produce new thoughts and follow-up questions that came up during the observations and the interviews. Further, the framework gave a very good overview of the results. The separate methods are discussed further below.

7.1.1.1 Observation

The observations at the traffic- and alarm centre were made as direct observations (Maguire 2001) at the workplaces while the operators were working. Only by watching the operators work, we gathered a lot of information, which is the advantage with observations that Preece, Rogers and Sharp (2002) mention as well. Unfortunately, we can also agree with them on the disadvantage, that observation is very time consuming and results in a lot of data to structure. To gather information about how similar work is made on other places for public transport we also visited the Swedish Road Administration and Metro Copenhagen (see section 4.1.1.2 and 5.1.1.3). To collect ideas for certain parts of the prototype, in this case the telephone system and the touch screen usage, we visited SOS Alarm (see section 4.1.1.4) and an information kiosk at the tourist information i n Gothenburg (see section 4.1.1.1).

7.1.1.2 Interview

The interviews were performed as informal interviews (Preece, Rogers & Sharp 2002) with a set of predetermined questions structured after the framework, as a support. The operators were interviewed while they were working and we could therefore easily ask them about their tasks and the systems, etcetera. Löwgren and Stolterman (1998) also claim this is the best way to perform the interviews. One advantage we found at the traffic- and alarm centre, was that since the operators are sitting close to each other they started to discuss the questions we asked and the answers were therefore

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more thoroughly investigated and several views could be gathered at the same time. The only disadvantage we noticed was when the operator had to speak in the radio system, or when the operator received a telephone call, the interview was interrupted, and when everything went back to normal it was hard to carry on. Sometimes questions had to be asked three or four times before an answer could be given.

7.1.2 HTA

We used the HTA because, according to Preece, Rogers and Sharp (2002), it concentrates on the physical and observable situations not related to any particular software or device, which is just what we wanted. We wanted to gather information about every event that occurs at the traffic- and alarm centre. To make a limitation we concentrated on what is happening in case of a fire in the subway (see section 5.4). The HTA was discovered to be a very good way to find out information about the work routines, who performs them and in what order. The method gave a lot of information rather easily and without loads of data to structure.

7.1.3 Paper prototyping

We wanted an easy way to get feedback and comments from the users and to find out if we were on the right track. According to Barnum (2002) paper prototyping is the way to get information cheap, fast and easy. The method worked well. The users understood what we wanted with the prototype and it gave rise to many discussions. Beforehand we had planned that the users should interact with the prototype themselves, but it worked a lot better if we described the prototype and what we had thought when developing it and let them comment instead of interacting.

7.1.4 Final prototype

To develop a software prototype to let the users and managers at the subway corporation know what possibilities there are to improve their workplace was the goal of this project. We agree with Barnum (2002) who says that high-fidelity prototypes are usable because the developer can get feedback from the users, though the product is not fully developed. In the final prototype, the focus was on solving the needs identified from the methods. By creating the software prototype, the operators and managers seemed to get a better understanding of what positive effects such a workplace could bring to the subway corporation.

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7.2 Prototype

In this project both the environment of traffic- and alarm centre and the operators have been in focus to design a prototype, in the field of HCI, connected to all analysed needs and requirements. As also Andersson and Sandblad (2003a) mention as important in their guidelines for designing graphical interfaces the design has to be seen as a part of the whole environment. Milner and Wheeler (2001), Gunnarsson and Gustavsson (1997) and Boring et a l . (2005) furthermore claim how important it is to connect HCI and human factors to the design of control rooms to meet safety and usability. According to Andersson and Sandblad (2003a) and their principles for designing graphical user interfaces for operators the developed prototype can be connected to some defined strategies. One strategy for example is the guideline concerning identifying the situations and the processes that are time dependent. These routines have been discovered in the field study and encountered for in the prototype. Examples are the telephone activities and the log system that we have tried to make more time efficient and simplified in the prototype. Similarly to the Swedish Road Administration that uses a large screen solution, we suggest a large screen for the subway corporation to receive a better overview of the total situation. We also suggest a common part on the large screen (see figure 5.2 in section 5.4) where the operators can receive status from all the operators DSS. This will lead to a better overview of the alarm situation, which we think is important to reduce stress and to increase safety. This is in line with Sandblad e t a l . (1998), and their suggestion of overview and awareness of the systems at the same time. According to the workplaces at Metro Copenhagen, the control room we suggest is specifically divided into different workplaces where the different operator roles are in charge of defined areas. We believe the different workplaces presented in the prototype (see figure 5.2 in section 5.4) can make the environment quieter and not as loud as today. Another similarity to Metro Copenhagen is the operator role in charge of infrastructure. We think that several needs identified at the subway corporation can be solved with a specific operator role in charge of the infrastructure systems.

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7.2.1 DSS

The developed DSS is a way to guide the user not to make the wrong decisions during an alarm situation. This is well connected to Andersson and Sandblad (2003a) guideline about the importance of designing against human errors and wrong decisions. To make the right decisions during an alarm situation can be hard and human performances influence the process. Montgomery (1992), also indicates how decision-making is a process that takes time and where all information for the situation needs to be considered. Within the DSS developed in the prototype, the operators receive support during a critical situation. The result of using a DSS will make human performances, such as stress and the time it takes to make a decision, not that crucial for the outcome of the alarm situation. The operator receives an automatic suggestion of how to act and what to do next in the situation. If the human performances are affected by the situation, the DSS can lead to better safety. The study of Canos, Alonso and Jaén (2004) also indicates how their multimedia application including a security plan for public transport, lead to reduced response time and human errors, which we think the DSS for the subway corporation, has the opportunity to do as well. The operators using the DSS in CSS for the Swedish Road Administration mentioned that in some cases they perform the activities manually. This is catered for in the prototype since the automatic decisions are suggestions and the operator can always modify them. We think that a very positive aspect is that the operators are not obliged and does not have to do as the DSS suggests. They can still perform the activities in their own way. SAAB (2005) states the same principal; how the operator has to be in control of the system and not vice versa, and that an operator never should be replaced by a system. The DSS for the subway corporation is not completely automatic and could never replace the operator. One of the differences when comparing the prototype to CSS used by Swedish Road Administration is that in CSS one of the operators has to take control of the system, and the DSS is current for only one operator at a time. In the prototype, several DSS are active at the same time and the operators can cooperate during an alarm situation. This cooperation is unique and we think it will increase the support and the safety. Filippi and Theureau (1993) claim how the interrelations between the operators are important and how their support system can lead to a better overview and understanding of the situation. We think the DSS in the prototype can improve the cooperation between the operators and also create a better understanding and overview of an

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alarm situation. For example the prototype includes a log system and all operators’ progress in the DSS can be seen in the prototype and the operators can survey the total situation. The prototype also includes solutions for better communication, both telephone activities and communication between the operators, to increase the cooperation. The communication between the operators are improved by using a better placement, designed after which operators who talks to each other the most and what tasks they perform. Sometimes the operators communicate through the system as well. By having separate workplaces for each operator the responsibilities become clearer. Andersson and Sandblad (2003b) describe their support for train traffic control and how the system visualises the alarm process with further information to help the operator. Montgomery (1992) also claims how all information about the situation needs to be considered to make a decision. The developed interactive DSS in the prototype also visualises the alarm situation for the operators, which we think will lead to a better understanding and a better overview, which will make it easier for the operators to make decisions within the DSS. The DSS graphically visualises the activities and supports the operator with information, which also Jacobs (1989) mention as two important tasks for a DSS. Norman (2000) also states the importance of visualising technology to improve feedback. The operator receives feedback in the DSS through graphical representations after performing the activities. A problem Sandblad et al. (2003) and Boy (1998) mention is how the operators do not use the DSS because the alarm situations are too complex and the operators want to be in control. The DSS for the subway corporation is built upon a specific scenario and the goal is to visualise how interactive DSS and a touch screen can solve several of the identified needs. How the DSS should be developed for all different complex situations is not analysed in this project. We think that if the subway corporation develops and implements a DSS for their unique organisation a user centred design process should be used. A process where the users’ needs are in focus will make the operator use the DSS no matter how complex the problem is. All aspects around the operator are important. If all needs and requirements are not identified it can lead to a DSS not used at all and if used it can even have a negative result in an alarm situation. An aspect also mentioned by Ottersten and Balic (2004) is the fact that the whole environment can lack in efficiency if the IT-solutions are not designed properly. For example the Grabowski and Sanborn (2003) study showed how the operators’ attitude towards new technology could result in a negative influence. Involving the operators in such a

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process would identify the attitude before a development and should therefore never lead to a negative result. Turban, Aronson and Liang (2005) suggest how a DSS can be integrated with the systems, and the systems can complement the other, which can lead to new benefits. Hopley, Holden and Wilhelmij (2000) also claim how DSS can be connected with the whole operating process. The DSS for the subway corporation integrate several systems, which we see as a very positive development for the work in the control rooms, since the operator receives a support through the whole process during an alarm. By using the prototype developed in his project the contributory causes for stress will decrease since the causes Kontogianis (1996) stated as risk factors are taken into account by developing the DSS. The right information is always at the right place at the right time when using the DSS. By using the computer based DSS the subway corporation can take away the paper support (the paper-based emergency plan), which is good since Wastell and Newman (1996) claim how computer based support, compared with paper-based support, decrease the stress level and increase the operator performance. Several of the needs at the traffic- and alarm centre (see section 6.1) such as a calm and quiet workplace, increasing the physical space, and providing a better support for the operators feeling insecure, Desaulniers (1997) also states as causes of stress. He further states that a solution for stress reduction could be well-designed operating procedures to minimise the use of working memory and to distribute workload between the team members, which is exactly what we have tried to do in the prototype.

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7.2.2 Touch screen technology

The prototype is a mixture of pictures from already existing systems and new systems designed after the touch screen possibilities and limitations. We have discovered, as many other researchers (Karat, McDonald & Andersson (1986), Muratore (1987), Ahlström & Lenman (1987), Ostroff & Shneiderman (1988), Sears & Shneiderman (1989)) that the systems designed for a touch screen work better than the ones that are not. Mostly because of the too small buttons in the existing systems that are too hard to hit with the fingers. According to the analyses of the final prototype (see section 6.4) the activity buttons in the DSS and the workplace buttons were easy to hit, while the check boxes in the log systems were too small. The DSS interface made the process very fast which was confirmed by the operators at the analysis of the final prototype but also by the studies made by Karat, McDonald and Andersson (1986), Muratore (1987), Ahlström and Lenman (1987), Ostroff and Shneiderman (1988), and Sears and Shneiderman (1989) that resulted in the touch screens being faster than the mouse as long as the buttons are large enough. Therefore, and also because of the result of the observation at the information kiosk at Gothenburg tourist information (see section 5.1.1.1) we believe that every system that should be used on a touch screen must be designed and developed according to touch screen conditions. Some of the advantages and disadvantages listed by Shneiderman (1993) (see section 2.3.1) concern the field of usage for the prototype more than others. For example the advantage of touching a visual display requires little thinking and is a form of direct manipulation is exactly what we are striving for. We want the manipulation of the prototype to be as natural that the user does not need to think of it, instead direct all the attention to the task. The analysis of the prototype did not result in such comments or observations but all operators were inexperienced with the touch screen and the prototype, which might have been the reason. Another advantage (Shneiderman 1993) and one of the reasons why this project regards touch screens, is the opportunity to remove all devices for manipulating a screen from the crowded workplace at the subway corporation. Andersson and Sandblad (2003a) also state that one principle when designing graphical interfaces for control rooms is to avoid the use of too many different input devices. Unfortunately the prototype is still in need of a keyboard to be able to write in the log system. No extra research in this project is made in the area but how

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to develop text input for touch screen seem to be a problem not solved yet and also listed as one of the disadvantages by Shneiderman (1993). A second disadvantage when using a touch screen is that the hand of the user might obscure the screen (Shneiderman 1993). Therefore the prototype interface is designed so that buttons and systems, which demand more interaction, are placed at the edges and the bottom of the screen. This design is also supported by the study at the information kiosk (see section 5.1.1.1) and by Po, Fisher and Booth (2004), Danckert and Goodale (2001), and Beringer (1990) that all have found that interaction should be done at the lower part of the screen and surveillance at the upper. Many different techniques for interacting with a touch screen have been developed and studied. The most popular techniques seem to be the land-on, first-contact, and take-off techniques, which are studied by many (Sears and Shneiderman 1989, Murphy 1987, Potter, Berman and Shneiderman 1989, Shneiderman 1993, Potter, Weldon and Shneiderman 1988). For interacting with the prototype the take-off technique seem to be the most suitable, but to prevent an accident by choosing the wrong technique the prototype is developed to suite them all. At every activity that could lead to severe problems when making the wrong choice by for example pressing the wrong button, a safety net is added. The safety net consists of a pop-up box asking the user if it really is what he/she wants to do. Since the touch screen does not give the user any tactile feedback we have followed Benders advise (Bender 1999) to use auditory feedback instead. When a button in the prototype is pressed a click sound is heard and the experience of feedback intensifies. The shape of the buttons in the DSS has not any important function except for being large and easy to hit. As Breinholt and Krueger (1996) found in their study, the shape does not matter much, as long as it is continuous. In the background theory several touch screen technologies are presented (see section 2.3.5). If we were able to choose which one to use for the prototype we would have chosen the ultra touch screen. According to A D Metro (2005) the ultra touch screen has many advantages (see table 2.1 and 2.2 in section 2.3.5). It can be manipulated with a finger, glove, or stylus and is not sensitive to vandalism, scratch, dust, water, temperature, or chemicals, which makes it a suitable technology to use in a control room. We had an infrared touch screen to our disposal, which has been working fine to

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demonstrate and try the prototype on. For longer use though, we do not know how good it will work or for how long it will stand. The prototype is supposed to be used by one person at a time standing or sitting directly in front of the screen. This will eliminate the problems Leahy and Hix (1990), Hall, Cunningham, Roache, and Cox (1988) and Beringer and Bowman (1989) found of selecting targets with less accuracy from the side. The prototype should also easily be adjustable in height and angle to the operator and Lehman and Sutarnos (Lehman & Sutarno 1995 in Bender 1999) guidelines could be followed. There are very few studies of touch screens examining what effects that might come from a longer use, for example by using the touch screen as a workplace for performance of daily work. Most studies are made on information kiosks where the users very seldom are in contact with the screen. A longer use might be strenuous on arms and shoulders, especially when the screen is large. The analyses of the final prototype (see section 6.4) also indicated on problems with the large touch screen. Therefore we suggest further research must be made in this area to establish the effects from long-term usage of large touch screens.

7.3 Conclusions

The aim of this project was to develop a prototype that encounters for the needs in the control rooms, to support the work situation for the operators and thereby enhance the subway safety. The prototype will, if it is ever implemented at the subway corporation for real, support the work situation for the operators. If the work situation is supported, it will also enhance the safety at the subway since the operator easier can concentrate on the activities to perform than on what to perform, in what order, in which system, with which mouse, etcetera. One solution we want to bring forward and that we see has great potential is the usage of a large display as the one used for the prototype, which contains all systems one operator needs. This part of the prototype has solved many of the needs found at the traffic- and alarm centre (see section 6.1). The conclusions of the research questions of this master’s thesis follow:

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7.3.1 DSS

The first research question of this master’s thesis was how an interactive DSS can be developed to support the operator and enhance the safety. The prototype illustrate how an interactive DSS can be developed and how the activities can be integrated with the other systems. The DSS is developed to be adequate for the context and the specific organisation at the subway corporation. The operator should always feel that he/she is controlling the DSS and not vice versa. This is implemented in the prototype by letting the operators always confirm the automatic activities and have the possibility to change. The DSS is developed to support the user in an alarm situation through: reducing the time it takes to perform the activities, reducing the stress, facilitating making decisions, simplifying cooperation and communication between the operators, integrating concerned systems, and visualising the overview of the alarm situation. We believe a DSS can support the work for the operators, and thereby increase the subway safety.

7.3.2 Touch screen technology

The second research question of this master’s thesis was if a new kind of workplace with a touch screen interface could be more efficient than traditional solutions. A workplace consisting of a large display with touch screen function is hard to evaluate only by creating a prototype. Our opinions are that touch screen is a good solution when tasks are to be performed quickly, as for example in the DSS. The DSS is the only system in the prototype developed after the abilities and limitations of a touch screen. It is therefore hard to determine if the other systems would work as well as the DSS if they were developed the same way. One problem with a possible implementation of the prototype is that for every system integrated the interface must be redesigned. There is no doubt that interfaces designed for an ordinary display does not fit a touch screen solution. To be able to answer the research question about touch screens as a new kind of workplace there must be further investigations and evaluations made. However, touch screens as a means for manoeuvring a DSS will be a good solution.

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7.4 Future work

Concerning the future for the subway corporation, we think that the field study and the implemented prototype will result in an urge for wanting to change and make the work situation better. The operators have been a part during the whole process and thoughts about how to support the operators and increase the safety have hopefully started. Davis (2002) described how knowledge about human performances improved the work in the control room through practical initiatives from the operators. We think the field study of this project has lead to awareness among the operators, which can lead to further ideas from the operators and a willing to change. Within this project, the subway corporation has received a good knowledge base with lots of possibilities for further work. We see the following areas as most useful and gainful to develop further: DSS, telephone system, integrating systems, feasibility study concerning workplaces and a large screen for a new control room. A DSS can be developed very simple and does not need to integrate that many systems as in the prototype. A DSS can also be a digital document with information direct from the emergency plan and with simple checkboxes. We also suggest the subway corporation to develop a telephone system which would make the work routines in the control rooms much more efficient. In the DSS, most of the activities concern calling and a telephone system could therefore be seen as a great support for the operator. Integrating the systems in the control room could also support the operator more, and specific functions in a system can be integrated with other functions in other system, which can lead to immense profits. A feasibility study where the workplaces and a large screen is further investigated is necessary if the subway corporation decides to build a new control room. A further study in the field of HCI where more requirements and needs for the specific situation connected to the technology is necessary. An important fact to have in mind since Ottersten and Balic (2004) claim that technology to improve work routines is no solution itself and if not planned the projects often becomes more expensive than expected. Likewise, Preece, Rogers and Sharp (2002), Löwgren and Stolterman (1999), and Winograd (1997), describe the importance of HCI and how important it is to design for the interaction between the user and the unique environment in that specific situation.

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8 ACKNOWLEDGEMENTS This project has been very interesting and motivating for us before finishing our studies in interaction design. As a final project it has been perfect with a challenging environment to study. We would like to give special thanks to the people that have supported and helped us in our work. In no particular order:

Infracontrol – Everyone at Infracontrol. Thank you for letting us feel as a part of your workplace. Thank you for your concern and interest in our work. We really enjoyed the Christmas party.

Johan Höglund – Thank you for the opportunity to do an interesting and meaningful project.

Thomas Havsberg – Thank you for your help and support at the subway corporation.

Jonas Bratt – Thank you for your help with the touch screen, and for rescuing us when the computer did not work the hour before our final presentation.

Catherine Walther – Thank you for organising the travels.

The managers at the subway corporation – Thank you for giving us an interesting workplace to study and for your engagement.

The operators – Thank you for your good explanations and for giving us invaluable information about your workplace.

Lena Palmquist – Thank you for your great tips and corrections.

Olof Torgersson – Thank you for your advices in the field of HCI.

Family and friends – Thank you for your support and patience.

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APPENDIX

1 Interview questions

Workplace

· What do you think about the physical appearance of your workplace?

· Do you have any wishes for how to change the workplace? · Have you been visiting other control rooms? · Do you have any opinions, design preferences, or

expectations about the new control room planned to be built?

Work routines

· Do all operators have different work tasks? · Are there any specific hierarchic orders for the operators? · What are the work routines during a shift? · What work routines do you start with? · What work routines do you focus on most? · What work routines are most time consuming? · What kind of work task is most interesting and fun

respectively most boring? · Do you have any suggestions for how to facilitate your work

routines? · Are there any work routines that are paper based? · What do you do if there is an alarm situation? · Do you have routines for what to do in an alarm situation? · What kind of different alarms are coming into the control

room?

Appendix

Stress

· How often is there an alarm situation? · How do you know what to do when there is an alarm

situation? · Do you feel stressed during an alarm situation? · How often do you feel stressed? · What happens when you feel stressed? · How is the work divided between the operators during an

alarm situation? · Do you have routines and manuals for what to do during an

alarm situation? · Do you think that the subway is safe for the travellers? · Do you know in which order to perform activities during an

alarm situation? · How often do you feel insecure and do not know what to do?

Communication

· With which other people or operators do you communicate? · How do you communicate with the other operators? · What devices do you use for communicating? · Do you see any problems concerning the communication in

the control room?

System

· What different systems do you use? · What system do you use the most? · What system do you use the least? · Are there any systems that you think are unnecessary? · Who is in charge of maintaining the systems? · Who is in charge of buying the systems? · What do you think is good/bad about the different systems? · What do you think about the graphical interfaces? · Are there any systems with similar functions? · What kind of input device do you prefer? · Do you have to move a lot between the systems? · How do you like working with a touch screen?

Documents

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