Copyright Rajendra Kumar MIET Human Computer Interaction Author – Rajendra KumarRajendra Kumar Email – [email protected] [email protected] Publication

Copyright Rajendra Kumar MIET

Human Computer Interaction

Author – Rajendra Kumar

Email – [email protected]

Publication – Firewall Media, Delhi

Edition – 2005 (First)

Reprint – 2005, 2006

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Interaction Generally, an interaction is a kind of action which occurs

as two or more objects have an effect; in some cases, a difference between the two should be distinguished. For example, the interaction between a driver and the position of his or her car on the road: by steering the driver influences this position, by looking this information returns to the driver; the feedback during operation of other machines such as a computer or a tool; two people talking to each other (sometimes the interaction is not satisfactory, because one or both do not listen well).

Chapter 1 Introduction


Chapter 1 IntroductionHuman-Machine Interface In communications, interactive communication occurs when sources take turns transmitting

messages between one another. This should be distinguished from transitive communication, in which sources transmit messages simultaneously. In medicine, most medications but particular combinations of medicines need to be monitored for interactions, often by the pharmacist interactions between drugs fall generally into one of two main categories; pharmacodynamic (involving the actions of the two interacting drugs), and pharmacokinetic (involving the absorption, distribution, metabolism, and excretion of one or both of the interacting drugs upon the other). Sometimes two or medications are used together to create an extra effect - e.g. two different pain killers to provide more complete pain control. These interactions are usually intentional but need to be monitored by the doctor because patients can end up with more effect than is actually required. Sometimes two or more medications work against each other. These interactions are usually well known and avoided unless both medicines are essential. Careful monitoring is used to prevent problems from the results of the interaction. Other interactions may cause one medicine to have less or more effect than expected and these are usually managed by a dosage adjustment. In physics, an interaction specifically refers to the action of one physical object upon another - the physical objects under consideration may range from point particles to quantum fields. For example, the interaction of charged particles takes place through the mediation of the electromagnetic field whereas beta decay occurs by means of the weak interaction.


Chapter 1 IntroductionHuman Interface Devices• A human interface device or HID is a type of computer device that interacts directly with and takes input from

humans, such as the computer keyboard, computer mouse, joystick, graphics tablet, and others. The term was coined by Microsoft when plugging in a USB keyboard or mouse, Microsoft Windows (and possibly other operating systems) will often show an "HID-compliant device" being recognized. This is generally not the case with the direct PS/2 5-pin DIN connectors which preceded USB, as these are recognized as native hardware by the BIOS firmware upon booting.

• User interface engineering is the engineering of the user interface. It addresses the need to develop interfaces that make users more productive. It is often considered as one of the more practical aspects of the field of human-computer interaction Human-computer interaction (HCI) is the study of interaction between people (users) and computers. It is an interdisciplinary field, relating computer science, psychology, cognitive science, human factors (i.e., ergonomics), design, sociology, library and information science, artificial intelligence, and other fields. Interaction between users and computers occurs at the user interface (or simply interface), which includes both hardware (i.e. input and output devices) and software (e.g. determining which, and how, information is presented to the user on a screen). Concerns include

• standards

• simplicity

• utility

• coherence



Human System InteractionHuman-system interaction includes a wide variety of systems and a wide

variety of humans who interact with them. One useful way of organizing and sorting out the number of associated design issues is to consider types of users and types of systems with which the users interact. Design issues and characteristics are widely acknowledged to be context-dependent— that is, both task- and user-dependent. As most human factors engineering practitioners and human-computer interaction texts point out: identifying and understanding the intended users and specifying the users’ needs are the fundamental prerequisites to effective design.



Human-Computer Interaction (HCI)Human-Computer Interaction (HCI) is the study and the practice of usability. It is about

understanding and creating software and other technology that people will want to use, will be able to use, and will find effective when used. The concept of usability, and the methods and tools to encourage it, achieve it, and measure it are now touchstones in the culture of computing. Through the past two decades, HCI emerged as a focal area of both computer science research and development and of applied social and behavioral science. Some of the reasons for its success are straightforwardly technical: HCI evoked many difficult problems and elegant solutions in the recent history of computing, for example, in work on direct manipulation interfaces, user interface management systems, task-oriented help and instruction, and computer-supported collaborative work. Other reasons are broadly cultural: The province of HCI is the view the non-specialist public has of computer and information technology and the impact that technology has on their lives in the sense that it is the visible part of computer science and technology. The most recent reasons are commercial: As the underlying technologies of computing become commodities, inscribed on generic chips, the non-commodity value of computer products and services resides in applications and user interfaces—that is, in HCI.



HCI Vs. CHI The acronym CHI (pronounced kai), for computer-human

interaction, has been used to refer to this field, perhaps more frequently in the past than now. However, researchers and practitioners now refer to their field of study as HCI (pronounced ach-see-eye), which perhaps rose in popularity partly because of the notion that the human, and the human's needs and time, should be considered first, and are more important than the machine's. This notion became increasingly relevant towards the end of the 20th century as computers became increasingly inexpensive, small, and powerful.



User Friendliness

A user interface is said to be user friendly if its human user find it easy to use. This definition reflects the subjective nature of user friendliness. An application that is used by novice programmers qualifies as user friendly by virtue of different properties than an application that is used by expert programmers. For example, a novice user may appreciate verbose messages, while an experienced user grows to detest and ignore them.


Chapter 1 IntroductionInteraction Techniques and Tasks

Interaction techniques are ways to use input devices to enter information into the computer, whereas information tasks classify the fundamental types of information antlered with the interaction techniques. The interaction techniques are defined as the primitive building plucks from which a user interface is crafted. An interaction task is the entry of a unit of information by the user. The four basic interaction tasks are:

– Position– Text– Select, and– Quantify

There are two types of interaction tasks:– Basic Interaction Tasks– Composite Interaction Task


Chapter 1 IntroductionInteraction TasksBasic Interaction Tasks

The interaction task that can not be decomposed into smaller units of information is called basic interaction task. Basic interaction tasks are indivisible. If they were decomposed into smaller units of information, the smaller units would not in themselves be meaningful to the application. The user of an interactive system enters a unit of information that is meaning full in the context of the application with a basic interaction task.

Composite Interaction Task

Composite interaction tasks are built on top of the basic interaction tasks, and are actually combinations of basic interaction tasks integrated into a unit. There are three major forms of composite interaction tasks

. Dialog box- used to specify multiple units of information

. Instructions-used to create objects reigning two or more positions.

. Manipulation- used to reshape existing geometric objects.


Chapter 1 IntroductionInteraction Styles• Direct Manipulation

Direct manipulation user interface is one in which the objects or attributes, or sedations that can be operated on are represented visually. The operations are invoked by actions performed on the visual representations, typically using a mouse. That is, the commands are not invoked explicit by such traditional means as menu selection or by keyboard; rather the commands are implicit in the action on the visual representation. This representation may be text, such as the name of an object or property, or a more general graphic interface.

• Menu Selection

Menu selection is the interaction style in which user reads a list of items, select the most appropriate item to his/her task, and observes the effect. Menu selection is the interaction style widely used by novices as well as intermittent users. The main advantage of menu selection interaction is that there is a clear structure to decision making, since all possible options are visible at one time. Following diagram (figure) shows a menu having option from which any option can be selection according to requirement.

• Form fill-in

The form fill-in interaction style is ideal when data entry is required. For data entry menu selection may be cumbersome. In form fill-in the user sees blank data entry fields that can be filled by moving cursor among the fields that can be filled by moving cursor among the fields with required data. In form fill in the user (operator) must know the labels of different fields, permissible data (character or/and numeric), and methods of data entry.


• Command language

The interaction style command language provides a strong feeling of tows of control for frequent users. In this interaction style the user is supposed to learn the syntax for his task. By this the user can express complex possibilities rapidly. The major drawbacks of this interaction style are:

– Error rate is typically high;– Retention may be poor;– Training is necessary; – Error messages and online assistance are difficult to provide

In this interaction style, command languages and lengthier queries are the domain of expert frequent users, who often drive great satisfaction by specializing complex set of syntax and semantics. Following diagram (figure) show a MS DOS prompt where the user’s command can be executed to perform his/her task.

• Natural language

Natural language interaction can be defined as the operation of performing tasks by computers by people using a familiar natural language (such as English, French, etc.) to give commands and receive responses.

In this interaction style the computer system is trained in such a way that it performs the user’s task by requiring command through human voice. In natural language interaction style, there is a little context for issuing the next command, which requires clarification dials. For some complex tasks, natural language interaction may be slower and more cumbersome than the other alternatives of interaction styles. The knowledgebase in such interaction style has limited options for user’s task.



Interaction Paradigms

– Hypertext : The World Wide Web (the Web or WWW for short) is a hypertext system that operates over the Internet. Hypertext is browsed using a program called a web browser, which retrieves pieces of information (called documents or web pages) from web servers (or say web sites) and displays them on your screen. You can then follow hyperlinks on each page to other documents or even send information back to the server to interact with it. The act of following hyperlinks is often called surfing the web.

– Hypermedia : Hypermedia is a term used as a logical extension of the term hypertext, in which audio, video, plain text, and non-linear hyperlinks are used to create a non-linear medium of information. This contrasts with multimedia, which, although often capable of random access in terms of the physical medium, is essentially linear in nature.



Chapter 1 Introduction• Hyperlink : A hyperlink, or simply a link, is a reference in a hypertext document to

another document or other resource. However, combined with a data network and suitable access protocol, it can be used to fetch the resource referenced. This can then be saved, viewed, or displayed as part of the referencing document.

• URL : Uniform Resource Locator, URL (pronounced as earl or spelled out), or web address, is a standardized address for some resource (such as a document or image) on the Internet. First created by Tim Berners-Lee for use on the World Wide Web, the currently used forms are detailed by IETF standard RFC 2396 (1998). The URL was a fundamental innovation in the history of the Internet. It combines the four basic items of information necessary into one simple address to find a document anywhere on the Internet:

– The protocol to use to communicate with that machine – The machine or domain name to go to – An open network port on the target machine connected to some service – The path or file name on that machine

For example http//www.geocities.com/kumar_rajen/toa and http//www.geocities.com/rk_hci are valid URLs.


Chapter 1 IntroductionInteraction Devices The Computer system – A computer system is defined as

the collection of peripherals (input and output devices) connected to the CPU, ready for users’ tasks.


Chapter 1 IntroductionInteraction Devices • Input and Output devices

The Keyboard: A keyboard is a data entry or control device using a number of keys which are to be pressed by the fingers. There are two main types of keyboard:

• Alphanumeric keyboards (including the typewriter keyboard, the generic computer keyboard and its descendant the IBM PC keyboard)

• Musical keyboards

The Standard English keyboard layout is known as QWERTY.


Chapter 1 IntroductionInteraction devices: Row 1 (left to right) mouse, 3D mouse, joystick, microphone

Row 2 (left to right) track ball, web camera, digital camera, touch screen, light pen



Fields of HCIThe goal of this section is to provide background about HCI group in

terms of some of the major themes and influences that have shaped the field of HCI. In addition, an attempt is made to project some current trends into the near future as a basis for anticipating some of the conditions with which students will be faced upon, or even before, graduation. This section is not intended to provide either an exhaustive history of the past or a full scale futures projection. It is,

rather, to provide a context for the recommendations.


Chapter 1 IntroductionLikely Future Developments

The means by which humans interact with computers continues to develop rapidly. A curriculum in a changing area must be put together with some understanding of the forces shaping the future so that its concepts are not quickly out of date. The forces shaping the nature of future computing in the first instance, affect human-computer interaction. These forces include:

• Decreasing hardware costs leading to larger memories and faster systems.

• Production of hardware in compact form that leads portability.

• Reduction in power requirements leading to portability.

• New display technologies leading to the packaging of computational devices in new forms.

• Assimilation of computation into the environment (e.g., VCRs, microwave ovens, televisions).

• Specialized hardware leading to new functions (e.g., rapid text search).

• Increased development of network communication and distributed computing.


Chapter 1 Introduction• Increasingly widespread use of computers, especially by people who are outside of the

computing profession.

• Increasing innovation in input techniques (e.g., voice, gesture, pen), combined with lowering cost, leading to rapid computerization by people previously left out of the computer revolution.

• Wider social concerns leading to improved access to computers by currently disadvantaged groups (e.g., young children, the physically/visually disabled, etc.).

The Contents of Human-Computer InteractionThe interrelated aspects of human-computer interaction are:

The nature of human-computer interaction, the use and context of computers, human characteristics, computer system and interface architecture, and the development process.


Chapter 1 IntroductionNature of Human-Computer Interaction It includes following concern with the nature of work, and with the notion that

human systems and technical systems mutually adapt to each other and must be considered as a whole:

• Points of view (e.g., industrial engineering, operations research, Rasmussen's cognitive engineering, the Aarhus participatory design approach, Hewitt's open systems)

• Models of human activity (e.g., opportunistic planning, open procedures)

• Models of small-groups, organizations

• Models of work, workflow, cooperative activity, office work

• Socio-technical systems, human organizations as adaptive open systems, mutual impact of computer systems on work and vice versa, computer systems for group tasks, case studies

• Quality of work life and job satisfaction


Chapter 1 IntroductionApplication Areas The main applications are:

• Characterization of application areas (e.g., individual vs. group, paced vs. unpaced).

• Document-oriented interfaces: Text-editing, document formatting, illustrators, spreadsheets, and hypertext.

• Communications-oriented interfaces: Electronic mail, computer conferencing, telephone and voice messaging systems. D

• Design environments: programming environments, CAD/CAM.

• On-line tutorial systems and help systems.

• Multimedia information booths.

• Continuous control systems: process control systems, virtual reality systems, simulators, cockpits, video games.

• Embedded systems: Copier controls, elevator controls, consumer electronics and home appliance controllers (e.g., TVs, VCRs, microwave ovens, etc.).


Chapter 1 IntroductionGoals and Aspects of HCIA basic goal of HCI is to improve interaction between user and

computers, by making computers more user-friendly and easier to use. More broadly, HCI is also concerned with:

• methodologies and processes for designing interfaces (i.e., given a task and a class of users, design the best possible interface within given constraints, optimizing for a desired property such as learnability or efficiency of use);

• methods for implementing interfaces;

• techniques for evaluating and comparing interfaces;

• developing new interfaces and interaction techniques;

• developing descriptive and predictive models and theories of interaction.



The HCI GroupThe Human-Computer Interaction Group was founded in 1984 to pursue

research into the design and evaluation of interactive systems. The group has a unique interdisciplinary approach which integrates rigorous formal methods from the latest software engineering research, with theories of perception, learning and error, developed within cognitive and social psychology, sociology and linguistics. The group’s concern is not just with the usability of computers for the single user in isolation but also usability in the context of users' tasks and communities, as well as for groups of collaborating users, and for users with special needs, such as disabled users and operators of safety-critical systems.

As an example, the HCI Group at Cornell University is an interdisciplinary research team investigating social, psychological, and design issues surrounding the use of computers at school, work and home.

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Copyright Rajendra Kumar MIET Human Computer Interaction Author – Rajendra KumarRajendra Kumar Email – [email protected] [email protected] Publication