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AN EMBEDDED DYNAMIC QUERYING SYSTEM
/
by Ong Chooi Sim
A dissertation submitted in partial fulfilment of the requirements for the degree
of Master of Information Technology
Faculty of Information Technology UNIVERSITI MALAYSIA SARAWAK
July 1995
DECLARATION
No portion of the work referred to in this dissertation has been submitted in
support of an application for another degree or qualification of this or any other
university or institution of higher learning.
ii
ACKNOWLEDGMENTS
My most sincere thank to Associate Professor Dr. Zaidah Abdul Razak for her
guidance and support in this study and her patience with the many detours that
I have taken along the way. Her teaching and encouragement brought me to
the emerging world of IT. Leng Chee Kong, my co-supervisor, has given me a lot
of valuable suggestions and guidelines that has eased the system development
process. Special thanks to Professor Dennis Longley for his comments and
assessment.
Also, I would llke to express my thanks to Professor Dr. Mohd. Zahran Halim for
his teaching in Software Engineering, Narayanan K. for introducing me to the
exciting world of distributed computing and networking and Beverly LaRock for
sharing her knowledge in management issues and the opportunity of studying
the real world situation in IT field.
Pek Wan, Yong, Sham, May, Reuben and Alvin, were always there to listen to
my ideas. I feel thankful for their constant encouragement. I also do not forget
all the other helpful and friendly lecturers and staff in the Faculty of
Information Technology.
I really appreciate the help from Adrian and Kum who spent their valuable time
to edit this report. Also, I would like to say “Thank you very much to all my
friends for their support and encouragement.
Last, my “endless” thanks to my family for their love that have kept me going ....
Ong Chooi Sim
... 111
TABLE OF CONTENTS
Declaration
Acknowledgments
Table of Contents
List of Figures
Abstrak
Abstract
.. 11
... 111
iV
ix
xi
xii
1 Introduction 1
1.1 Intelligent Database Environment ............................................... 2
1.2The Need for Dynamic Iconic Querying ....................................... 3
1.2.1 Other Existing Query System .............................................. 3
1.2.2 Why Dynamic Iconic Querying ........................................... 4
1.3 Scope of Study ............................................................................... 5
1.4 Research Objectives ...................................................................... 5
1.5 Synopsis ......................................................................................... 6
. .
2 Background 8
2.1 Types of Query System ................................................................. 8
2.1.1 Text Based Query ................................................................. 8
2.1.2 Form Fill-In .......................................................................... 9
2.1.3 QBE ....................................................................................... 9
2.1.4 Incremental Modification ..................................................... 10
2.1.5 Dynamic Queries .................................................................. 10
2.2 User Interface ............................................................................... 11
2.3 Hypermedia ................................................................................... 12
2.3.1 Hypermedia Features ........................................................... 13
2.3.2 Advantages of Using Hypermedia System .......................... 13
2.3.3 Shortcoming of Current Hypermedia system ...................... 13
iv
2.3.4 Current Hypermedia Trends ................................................ 14
2.4 Other Terminology ........................................................................ 15
3 Literature Survey 16
3.1 Graphical Interface Querying ...................................................... 16
3.1.1 Visual SQL ............................................................................ 16
3.1.2 Iconic and Hypertext Querying ............................................ 17
3.1.3 Interface for Scientific System ............................................. 18
3.1.4 GOQL .................................................................................... 19
3.2 Dynamic Queries ........................................................................... 20
3.2.1 Principles of Dynamic Queries ............................................. 20
3.2.2 Main Features of Dynamic Queries ..................................... 21
3.2.3 Advantages and Disadvantages of Using Dynamic
Queries .................................................................................. 23
3.3 Summary ....................................................................................... 24
4 Research Methodology 25
4.1 The Aims of the Research ............................................................. 25
4.2 Research Schedule ........................................................................ 25
4.3 Hardware and Software Requirements ....................................... 27
4.4 System Architecture ..................................................................... 28
4.4.1 System Overview .................................................................. 28
4.4.2 Database and ERD Design ................................................... 28
4.5 User Interface ............................................................................... 31
4.5.1 Query Devices ....................................................................... 31
4.5.2 Front End Interface Design ................................................. 32
4.6 Establish the Connection ............................................................. 32
4.7 Summary of the Development Steps ............................................ 32
5 Implementation 34
5.1 Database Issues ............................................................................ 34
5.1.1 Create a Local Database ..................................................... 34
v
5.1.2 Create New Tables and Columns ........................................ 34
5.1.2.1 Data Type ................................................................. 36
5.1.2.2 Test Data .................................................................. 37
5.2 Dynamic Iconic Querying System ................................................ 37
5.2.1 SQLWindows: Dynamic Iconic Querying (DIQ)
Application ............................................................................ 37
5.2.2 MDI Top Level Module ......................................................... 38
5.2.2.1 The Child Windows System Overview .................... 39
5.2.3 Staff Details Module ............................................................. 43
5.2.3.1 Tables and Columns That Were Selected for
Querying Purposes ................................................... 43
5.2.3.2 Query Devices ........................................................... 43
5.2.3.3 Query Interface: Boolean Feature Included ............ 45
5.2.3.4 Query Result Presentation ...................................... 46
5.2.3.5 Scenario .................................................................... 48
5.2.4 Staff Publication Module ...................................................... 48
5.2.4.1 Tables and Columns That Were Selected for
Querying Purposes ................................................... 48
5.2.4.2 Query Devices ........................................................... 49
5.2.4.3 Query Interface: Boolean Feature Included ............ 50
5.2.4.4 Query Result Presentation ...................................... 51
5.2.4.5 Scenario .................................................................... 51
5.2.5 Staff Project Involvement Module ....................................... 52
5.2.5.1 Table and Columns That Were Selected for
Querying Purposes .................................................... 52
5.2.5.2 Query Devices ........................................................... 52
5.2.5.3 Query Interface ........................................................ 52
5.2.5.4 Query Result Presentation ...................................... 53
5.2.5.5 Scenario .................................................................... 53
5.3 Embedded Query in a Hypermedia Application .......................... 53
5.3.1 User Interface Design in Toolbook ...................................... 54
5.3.2 Connection Between SQLWindows and Toolbook .............. 55
vi
5.3.2.1 OLE Issues ............................................................... 55
5.3.2.2 Establish the Connection Through Object
Package ..................................................................... 56
5.4 Features of Selected Products ...................................................... 56
5.4.1 The Features That Discovered ............................................. 56
5.4.2 Limitations ............................................................................ 57
6 User Evaluation 58
6.1 Method ........................................................................................... 58
6.1.1 The Questionnaires ............................................................... 58
6.1.2 The Evaluation Environment.. ............................................ 58
6.1.3 Selected Subjects .................................................................. 60
6.2 Result ............................................................................................ 60
6.3 Comments and Suggestions ......................................................... 62
6.4 Conclusion ..................................................................................... 62
7 Discussion, Conclusion and Future Work 64
7.1 Discussion ...................................................................................... 64
7.1.1 Strengths and Weaknesses .................................................. 64
7.1.2 Limitation of the Prototype System................................... 65
7.1.3 Findings ................................................................................ 66
7.2 Accomplishments .......................................................................... 66
7.3 Future Work ................................................................................. 67
7.3.1 Future Enhancement of Dynamic Iconic Querying ............ 67
7.3.1.1User Interface ............................................................. 67
7.31.2 Intelligent Dynamic Iconic Querying System ........... 68
7.3.2 Connection to Database Server ............................................ 68
7.3.3 Extension to WWW ............................................................... 69
7.4 Concluding Remarks ..................................................................... 69
Bibliography .............................................................................................. 71
References ................................................................................................. 73
vii
Appendix A Source Code ........................................................................... 74
Appendix B The Embedded DIQ System Interface ................................. lOl
Appendix C Test Data .............................................................................. 106
viii
Figure 1.1
Figure 2.1
Figure 2.2
Figure 2.3
Figure 2.4
Figure 3.1
Figure 3.2
Figure 3.3
Figure 3.4
Figure 3.5
Figure 4.1
Figure 4.2
Figure 4.3
Figure 4.4
LIST OF FIGURES
Functional Model of An Intelligent Database Application Event
Handler ............................................................................................. 2
A Simple Text Based Query ............................................................. 8
A Form Fill-In Interface ................................................................... 9
An Incremental Modification System ............................................ 10
HomeFinder Dynamic Queries System Interface .......................... 11
A Query in Visual SQL With Two Conditions Using AND and
OR in the Same Query .................................................................. 16
Iconic Query System Interface ....................................................... 17
Tioga User Interface ....................................................................... 19
HomeFinder Dynamic Query User Interface ................................. 22
Filter/Flow Boolean Query User Interface .................................... 23
Research Schedule .......................................................................... 26
Dynamic Iconic Querying System Overview .................................. 28
Six Relevant Tables in DIQ Prototype System .............................. 29
Entity Relationship Diagram That Represents the Relationships
Between the Six Entities ................................................................ 30
Figure 5.1 Quest Window for Defining New Column Details ......................... 35
Figure 5.2 MDI Selection Submenu Options With Mnemonic and Keyboard
Accelerator Keys ............................................................................. 38
Figure 5.3 Iconize the Windows ...................................................................... 39
Figure 5.4 System Overview of the Application Modules... ........... ......... ....... 39
Figure 5.5 Some Handy Built-In Query Devices
(a) Combo Box Query Device
(b) Radio Button Query Device ...................................................... .44
Figure 5.6 The Custom Control's Customizer ................................................. 45
Figure 5.7 Query Interface for Staff Details Module........... ............ ........ ...... 46
Figure 5.8 Form Format Query Result Display .............................................. 46
Figure 5.9 Office Location Map Design ........................................................... 47
Figure 5.10 The Links Between Tables and Columns Used in the Staff
Publication Module ......................................................................... 49
ix
Figure 5.11 Check Box Query Device ................................................................ 49
Figure 5.12 Range Query Device That Created Using Horizontal Scroll Bar .. 50
Figure 5.13 Query Interface for Staff Publication Module .............................. 50
Figure 5.14 Query Interface for Staff Project Involvement Module ................ 52
Figure 5.15 Author Mode Interface at Toolbook ............................................... 54
Figure 5.16 User Interface of the Prototype System ....................................... 55
Figure 6.1
Figure 6.2
Figure 6.3
User Evaluation Questionnaire ..................................................... 59
User Evaluation Result Table ........................................................ 61
User Evaluation Result Chart.. ...................................................... 61
x
ABSTRAK
Sejajar dengan perkembangan teknologi maklumat yang pesat, perolehan
maklumat menjadi semakin penting. Dengan ini, penciptaan satu sistem yang
boleh memudahkan pengguna bertanya kepada sistem untuk mendapatkan
maklumat lanjut tidak boleh diketepikan. Sehingga kini, "kuasa bertanya"
hanya terhad kepada mereka yang arif dalam bahasa SQL. Sistem pertanyaan
tampak dinamik adalah satu pendekatan yang menjanjikan antaramuka yang
cepat dan mudah difahami kepada pengguna bukan pakar.
Kajian ini bertujuan untuk merekabentuk, melaksana dan menilai suatu sistem
pertanyaan dinamik dan seterusnya mengembangkan idea ini untuk kegunaan
yang lebih umum. Dalam kajian ini, satu prorotaip telah dibina berdasarkan
produk komersial misalnyna "SQL Windows". 1ni kemudiannya digabungkan
dalam aplikasi hipermedia "Toolbook". Sistem pertanyaan tampak berikon
bahagian depan ini merupakan antaramuka kepada sistem maklumat. Dengan
cara ini, kenyataan "SQL" telah dibentuk secara automatik untuk mengekstrak
maklumat daripada pangkalan data hubungan.
Siste111 pertanyaan dinamik ini adalah dinamik, sebagaimana namanya. Sistem
ini membolehkan pencapaian keputussan yang cepat iaitu data yang melaluinya
telah ditapis di sepanjang proses untuk mendapat keputusan dan ini
mengelallkan jawapan "tiada penyelesaian" didapati. Keberkesanan sistem
seperti antaramuka pengguna yang efektif, manipulasi data secara langsung dan
kebolehan menapis data dan paparan tampak yang sesuai telah juga
diambilkira. 1a juga mempunyai ciri antaramuka "menunjuk dan memilih"
untuk menyenangkan pengguna membina kenyataan pertanyaan yang bermakna
kepada komputer.
Untuk menyempurnakan kajian ini, satu sessi penilaian pengguna telah
diadakan untuk menguji kesesuaian antaramuka dan keberkesanan sistem ini.
Maklumbalas dan cadangan pengguna adalah positif secara umum dan ini akan
dijadikan panduan masa akan datang agar prestasi sistem ini dapat
dipertingkatkan.
xi
ABSTRACT
As information technology continues to grow rapidly, we need to incorporate
simple querying features to allow end users to gain access to information. Often,
the query power is just limited to the expert user group who are proficient in the
use of SQL. However, "visual dynamic querying" is a promising approach that
may deliver the required fast and easy interface for the use of non-computer
experts.
This study aims to design, implement and evaluate a visual dynamic querying
system, and also to further extend the usability of dynamic querying to a more
general environment. We have developed such a prototype using readily
available commercial products such as SQLWindows and embedding the system
into a ToolBook hypermedia application. The visual iconic front end query
system forms the user interface from which SQL statements are automatically
generated to access a relational database.
The querying system is "dynamic" in that it dynamically manipulates the query
input and gets data directly from the database, and not some earlier static
version. Moreover, the system is "filtered" to further guide the users through
the query process and limit the selection to avoid a "No Match" result. Effective
features such as a friendly interface, direct manipulation of data, filtering
capability and proper visualisation are included. In addition, a simple pointing
and clicking interface helps users to incrementally build up query statements.
To complete this study, a user evaluation seSSIOn has been carried out to
evaluate the dynamic querying system's interface and the system's performance.
User's feedbacks and suggestions are generally positive and these are taken into
account for the system's future enhancement.
xii
1 INTRODUCTION
Information flooding or overload has forced us to create new ways to manage
large amounts of data. It is not easy to handle and comprehend megabytes of
data without a specialised tool. Thus, there exists a need for presenting a large
amount of information in a format that is easy to query and understand.
Additionally, to survive in today's competitive world, it is important that the
information be current and not be out-dated or redundant. Fast and easy access
to up-to-date information would give us more competitive advantage in decision
making and problem solving.
Nowadays, as a result of exploration of Information Technology (IT), an effective
system that aims to solve the problems will need to provide most of the features
listed below: (i) the ease of querying data from a database to aid users in
information retrieval; (ii) multimedia format of report presentation to get better
visualisation; (iii) the use of visual understanding features to avoid
disorientation of navigation; (iv) provide useful information discovery features to
discover buried data; (v) manage the quality of data to reduce the cost of errors
in data and also provides tools for the interpretation of the information inherent
in high-quality data; (vi) using text-based knowledge as a source for knowledge
based representation for reasoning, and last (vii) provide data fusion as a tool to
integrate multiple sources and formats of data to meet the needs of database
connectivity.
These features mentioned above has created a need for an intelligent database
environment that is able to manage a large database system and at the same
time provides tools to fulfil these requirement features. Intelligent database is
what has been defined as "Database that manage information in a natural way,
making information easy to store, access and use. -- Parsaye et al.". It cooperates
and helps human in problem solving as it brings the flexible power of the human
mind to large data stores [Pars93].
1.1 Intelligent Database Environment
To achieve the desired intelligent environment, we will look into the
development cycle of the intelligent system. Intelligent database development is
a closed loop process, which can be basically divided into four main steps: (1)
building components, (2) integrating components, (3) evaluation, and (4)
refinement. The components consist of a query processor, graphical package,
and discovery system. To move smoothly between these components, we make
use of hyperdata. Hyperdata acts as a bridge between the database and
hyperinformation view of the world. While, in the functional model, an event
handler is used to handle the actions from the user interface, refer to figure 1.1
for further illustration.
Information Discovery
User Interface Action
Event Handler
Visual Query
Presentation
Hyperdata
Figure 1.1 Functional Model Of An Intelligent Database Application Event Handler
In realising the advantages of having an intelligent database, the focus of this
study is towards the design and implementation of visual querying system on
hyperdata. Specifically, we will look into Dynamic Iconic Querying from a
commercial database embedded in a hypermedia information system. We aim to
develop a friendly query interface that produces multimedia presentation and at
2
the same time provide proper visual understanding features that prevents
disorientated navigation. The main concepts will stress on the dynamic and
filtering features that can aid users doing querying.
Using the principles of the development of intelligent database system, we will
build both the query and hypermedia prototype systems at the same time and
then integrate the two components together. Once, the embedded process is
done, the user evaluation study will be carried out and the refinement work will
follow. The result of this study can serve as a guide to others who plan to work
in the same area. Presently, we believe that there has been little, if not no work,
that implements such an integrated environment.
1.2 The Need For Dynamic Iconic Querying
In this section, we will discuss the need of having dynamic iconic querying. We
start with a brief introduction to five common query systems with some
discussion on the problems and issues surrounding them.
1.2.1 Other Existing Query System
There are five main types of query systems: (a) text based query language, (b)
form fill-in, (c) Query By Example (QBE), (d) incremental modification, and (e)
dynamic queries [Wist94]. Briefly, we will see what is the main difference
between these query systems, and a more detail explanation will be covered in
chapter 2.
(a) Text based query It uses command line basis which is hard for non-expert
users to browse an unfamiliar database. The problem with this type of query
system is that the all-or-nothing result is often not as friendly as other systems.
(b) Fonn fill-in It is something similar to text based query, where SQL-like
query is attached to the form, but it has better interface and is easier to use.
The shortcoming is that it has the same problem faced by text based system.
(c) QBE It has extended the form fill-in system to include expressions describing
the separate attributes. In QBE, finding specific element can be easily done by
3
entering full description, as well as finding patterns with guessing pattern
expressions. But, still it may be hard to find anomalies and similarities.
(d) Incremental modification system It presents an arbitrary item from a
database to users, which can be further modified to get the desired item. Due to
the reasons that items are displayed individually and the exact criteria or path
that have been used are hard to remember, this system fails to differentiate an
anomaly item from the normal item.
(e) Dynamic queries system Rapid, incremental and reversible changes to the
query criteria can be done easily. Pattern and similarities detection query can be
performed as long as the visualisation can display the data points in an
understandable manner.
From the above five types of query systems, we chose to develop the dynamic
query system. We believe that it has the most user-friendly interface which is
suitable for end-users who are wishing to access hypermedia systems.
1.2.2 Why Dynamic Iconic Querying?
Why do we want to include the dynamic iconic querying feature into our
hypermedia system? There are a number of reasons why we choose to do so. (a)
With easy and friendly user interface, users can use the system without any
guide from anyone, and this is important for an Information Kiosks system to be
successful. (b) We aim to get the system a dynamic instead of static capability,
that is the system able to get the input from the user and then retrieve the
relevant data. Instead of static data that are pre-coded and not changeable. (c)
With the ability of filtering, dynamic querying system may be able to guide users
by narrowing down their query scope. This also avoids the problem of getting
nothing match from a query. (d) Dynamic querying has many potentials if we
develop it with the appropriate visualisation interface. Dynamic querying might
be able to let non-expert users, which most of us are grouped under that, to
explore large complex database easily.
Thus, there is a need for developing a dynamic querying system, with features
such as point-and-click, filtering, good visualisation, and ease of access to large
4
databases. At the same time, there is also a need for developing a dynamic
iconic querying using commercially-available databases to provide an easy to
access and accurate information campus-wide system.
1.3 Scope Of Study
Most database research focus on areas like distributed DBMS [Ston94] [Darr94],
OODBMS [SjoI94] [Diaz94], knowledge bases, management systems, and
memory performance. One research that is carried out in the area of dynamic
querying [Shne94] stated that " ... current data-management tools cannot easily
satisfy these requirements for rapid searches, and rapid graphical display
methods are not widely available ... ". The author also mentioned that " ...
application-specific programming is necessary to take best advantage of dynamic
query methods ... ".
In our research, we are going to find out whether it will be feasible and what will
be the best way to develop an embedded dynamic iconic querying system using a
commercially-available DBMS product. Issues on how to present our
information effectively and efficiently will have to be taken into account.
Emphasis on GUI (Graphical User Interface), like user friendliness, flexible
user interface, informative interface, as well as data visualisation will be covered
in this study.
1.4 Research Objectives
The objectives of this study are:
1. To verify the feasibility of developing a dynamic querying system that uses a
commercially-available DBMS product.
2. To develop an iconic interface that has embedded dynamic SQL queries.
3. To evaluate user preference on customisation issues.
4. To identify the issues of incorporating querying system into a hypermedia
application.
5
1.5 Synopsis
The remainder of this dissertation report covers the following chapters:
Chapter 2: Background
Background information on a few main topics covered in the
research, such as querying systems, user interface, and hypermedia
systems.
Chapter 3: Literature Survey
Literature Survey on research that has been carried out in the areas
that are related to the study. Research on graphical query interface,
dynamic querying, hypermedia system and user interface are
explored.
Chapter 4: Research Methodology
This chapter elaborates on the plan and steps that are taken to
develop the embedded SQL query, user interface, and result
presentation.
Chapter 5: Implementation
This chapter discusses the three main implementation sections: (i)
database issues, (ii) dynamic querying system, and (iii) embedded
query in a hypermedia application. In section (i), it will cover the
development of a local database using a commercially-available
database management system. Section (ii) looks into the
development of a prototype dynamic querying system, which will
discuss the modules that are created, the interfaces, query devices,
result presentation format, and its special features. Section (iii)
touches on the development of a prototype hypermedia system using
authoring software product with visual programming features.
Issues on user interface design and how dynamic querying features
are embedded into the hypermedia system are also discussed. In
addition, at the last section, this chapter includes some discussion
on features and limitations that have been discovered.
6
Chapter 6: User Evaluation
This chapter shows the steps taken in the user evaluation and the
results obtained with some discussion on the evaluation.
Chapter 7: Discussion, Conclusion and Future Work
This final chapter discusses some useful tools, limitations and
constraints in the area of study along with conclusion and
suggestions for future work.
7
2 BACKGROUND
This chapter elaborates on the background information, explanation for the
terminologies and concepts that are covered in the study. The main areas
involved are querying systems, user interfaces and hypermedia systems.
2.1 Types Of Query System
There are basically five types of query system, which are: (a) text based query,
(b) form fill-in, (c) Query By Example (QBE), (d) incremental modification, and
(e) dynamic queries [Wist94]. The difference between these query systems are
essentially in the interface, the user friendliness and the search capability.
2.1.1 Text Based Query
Text based query systems like SQL and related languages have been
implemented on many platforms. It is on a command line basis, whereby a well
specified set of criteria is needed to produce results from the queries. This has
caused non-expert users the inability to browse through unfamiliar databases.
This text based query system is not flexible as it has no ability to narrow or to
widen the query scope. Furthermore, to find similarities and anomalies are not
an easy task as it might require manual comparison on a few query results.
However, a simple pattern detection can be done with some built-in statistical
functions and it also possible to give an output on a graphical display. An
example of a text based query is as follows:
Select ID, Name, Faculty
From Student, MStudent
Where Age < 25 and
Subject >= 5
Order by Age
Figure 2.1 A Simple Text Based Query
8
2.1.2 Form Fill-In
A form fill-in query system is similar to the text based query whereby a SQL-like
query is attached to the form. This query system can be either an interface to an
existing database query language or a direct interface to the database system.
An example is shown in figure 2.2. A form fill-in query system has a better
interface, and is easier to use compared to a text based systems.
However, the creation of a form still reqUIres knowledge of the underlying
database. Normally, users will not be able to change the pre-designed form's
layout. So, it may not be flexible in the sense of satisfying the user's needs. This
query system also faces the same problem as a text based query on the issues of
finding a pattern, anomalies and similarities.
2.1.3 QBE
Input Query
Name
Faculty
Query Result
Name Faculty Job Title
Figure 2.2 A Form Fill-In Interface
QBE stands for Query-By-Example. It was introduced by Zloof in 1975 and has
extended the form fill-in query system to include expressions describing the
separate attributes. This system presents to the user a set of labeled entries for
the attributes in the database. Like the form fill-in query, users are not required
to remember any syntax or semantics of the query language.
For QBE query systems, finding a specific element can be easily done by entering
a full description into the available entries. While for finding patterns, it might
have to work with a guessing pattern expression. However, this type of query
system is still hard in finding anomalies and similarities because of its fixed, and
rigid output format.
9
2.1.4 Incremental Modification
"Rabbit" (Williams, 1984) is an example of the incremental modification query
system whereby an arbitrary item from a database is presented for users to
modify until the desired answer is obtained. It works in such a way that the
item can be modified to get a series of items, all of which can be further
modified. Refer to figure 2.3 for further illustration.
Incremental Modification query system seems to be a natural way of getting a
set of results by narrowing down a larger set to a manageable subset. However,
there is a shortcoming to this approach as it is not easy to remember the exact
criteria or path that have been used to get the desired subset. So it is hard to
determine any pattern of similarities in the subset. Moreover, as modified
information are not displayed, the system will fail to differentiate an anomaly
item from the normal item.
2.1.5
Figure 2.3
Tltimtersa ~~."
FbMm,g@aprk~t/mmaru.f1re In@ mcrtf-1llImftll mtHl,~ ~r$lem.
An Incremental Modification System [Wist94]
Dynamic Queries
Dynamic queries system introduced by Ben Shneiderman and Christopher
Ahlberg in 1992 is one of the latest form of query systems. It comes with a
visualisation of data and a set of query devices for the database. Users can make
full use of the query devices to do rapid, incremental and reversible changes to
10
the query criteria that describes the selected subset easily. Some examples of
query devices are sliders, combo box, push button and check box.
This query system has the capability of fast accessing, incremental searching,
and direct feedback of results. As long as the visualisation can display the data
points in an understandable matter, the issues of pattern and similarities
detection can be done here. The visualisation feature is integrated into the
system and at the same time functions as a selection mechanism for the
interface. The interface of a dynamic queries system is shown in figure 2.4.
D),namiq query illteljace sho..-ing th~ Dy· nomic H011U!fmdcr (Williamsoll & Shnei· derman, /992), which kts user.' se/c(:t diff""nt paramt!r,rs of hous~ the)' an in· It~(ed in, vi" sliders and mcvemenr of a elinor ill the lIisuaUzmion.
Figure 2.4
2.2 User Interface
HomeFinder Dynamic Queries System Interface [Shne94)
One of the hottest topics in the field of Information Technology today is the
effectiveness of the user interface. Since the user interface is the visible aspect of
a software, most of the users tend to judge the quality of a software application
by its interface [Pars93]. Thus, user interface is a critical factor to determine
the success of an application.
II
The most effective way to suit a system to its users is to base it on the intended
users' mental models, knowledge structures, and work processor [Mcgr94]. In
addition, a good user interface design's principles as proposed by Gould and
Lewis (1985) were: early focus on users and tasks, empirical measurement, and
iterative design [Pars93]. A proper design of the user interface with strong task
orientation usually will reduce the problem of disorientation and it will lead to a
well acceptance by the users. Another issue of getting user acceptance will be
the flexible feature of customising the user interface, whereby users can
customise the interface to suit their own needs [Nise94].
As [Cons94] stated in his article, the intermediate user group is the largest
segment, but yet it is perhaps the most neglected group. He urged interface
designers to take notice of this intermediate segment and make a detailed
transitional interface that will be well-suited to bridge the gap between a novice
and an expert segments closer.
In short, simplicity, consistency, flexibility and efficiency determine the
friendliness of the user interface. Good user interface can express information
abstraction in human terms without undermining the power or functionality of
the application -- Kamran Parsaye. [pars93]
2.3 Hypermedia
Hypermedia is a combination of both multimedia and hypertext. A few
hypermedia systems that are common to users of Internet are Netscape, Mosaic,
Hyper-G and etc .. Hypermedia is not a new 'term' to a lot of IT developers and
users. The idea of hypertext was first being innovated by Bush in 1945. And the
first hypermedia project was developed at MIT in 1978. Parsaye defined
hypermedia as the inclusion of other media such as sound, graphics, and videos
in information networks and when hypermedia + hypertext + hyperdata =
hyperinformation [pars93]. Hypermedia is also defined as the technology that
tackles the problem of organisation and the access of multimedia information by
[Chua91].
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