BIT 2305: HCI
Introduction
1. Introduction to HCI
Humans
2. Human Cognition
3. Perception and Representation
4. Attention and Memory
5. Knowledge and Mental Models
6. Interface metaphors
Interactions
7. Input
8. Output
9. User Support
10. Interaction Styles
11. Information Architecture and Web Navigation
User-Centred Design
12. User-Centred Design
13. Methods for User-Centred Design
14. User-Centred Web Design
15. Usability Engineering
16. Guidelines and Standards
17. Prototyping
18. Evaluation
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Computer Supported Cooperative Work
Cooperative working
Classification of CSCW systems
Groupware Systems
Organization contributions.
Applications of multimedia systems in learning, computer vision, and entertainment.

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BIT 2305: HUMAN COMPUTER INTERACTION
INTRODUCTION TO HCI
Human Computer Interaction (HCI) is concerned with studying ways to design, prototype, evaluate and implement user interfaces that are easy to learn, efficient and pleasant to use.
Often it is hard to learn a new tool. This is particularly the case in the complicated world of the computer where there are many different technologies (software tools) and many different ways to access them (different hardware and different screen layouts). Bridging the gap between the technology and the user – making the technology easy to learn and easy to use – is concern and the task of the “user interface”. User refers to the different people who might be using a certain tool.
In these times of wide software distribution, there are actually many different users to consider when designing an interface. Interface seems to be the most appropriate word for describing how a person will need to get access to a technological capability. Any technology that is used by humans and even many that are not have some sort of user interface. Most user interfaces are simply design choices and arrangement of the visible or accessible features of a technology that can be used to bridge the gap to the technology’s capabilities. The user is the ultimate concern in the user interface and the user interface goes a long way in determining the success of a certain product.
When the concept of the interface first began to emerge, it was commonly understood as the hardware and software through which a human and computer could communicate. An Interface can be visualized as the place where contact between two entities occurs. The less alike those two entities are, the more obvious the need for a well-designed interface. The concept of an interface is not a new thing; there are many things in day to day life which are acting as interfaces.
Examples are:
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A doorknob is the interface between a person and a door.

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The steering wheel, accelerator, clutch and other dash board instruments are the interfaces between a driver and a car.

An interface thus, is the contact surface for a thing.
The shape of the interface reflects the physical qualities of the parties to the interaction (the interactors). A doorknob is hard and firmly mounted because of the nature of the hand that will use it. The doorknob’s physical qualities also reflect the physical aspects of its function. It is designed to be turned so that the latch is released and so that it is easier for the user to pull the door open.
An interface is a contact surface that reflects:
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The physical properties of the interactors.
The function to be performed.
The balance of power and control.

User interface is critical and important in any software design. The user interface of a system is often the yardstick by which that system is judged. A poorly designed user interface will result in a user interface which makes it difficult to use and leads to high level of user errors and in some extreme cases may renders the software system to be discarded irrespective of its functionality.
When computers were first developed the only people who could operate them were highly trained engineers and scientists. Today, computers are commonplace – in schools, hospitals, homes etc.
Today almost everyone operates a computer as part of daily life. Of course, individuals may not
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necessarily think about the fact that they are not operating a computer as when, for example, they make adjustments in their digital watch or operate a cash-dispensing machine at “the hole in the wall”. The interaction between end-users and the computer is said to take place at the “Human
Computer Interface” (HCI). The term “Human Computer Interface” is meant to cover all aspects of this interaction, not just the hardware. With so many people operating computers, it is very important to make computers as easy to use as possible. Not only that, specialist user of computers, such as engineers in nuclear power stations, need to have an HCI available to them which will minimize the risk of them making mistakes when operating the computer systems under their control. A fundamental reality of application development is that the user interface is the system to the users. What users want is for developers to build applications that meet their needs and that are easy to use. It is for these reasons that in recent years a great deal of research and development work has gone into gaining a better understanding of what constitutes a good user interface and how to design. The reality is that a good user interface allows people who understand the problem domain to work with the application without having to read the manuals or receive training.
The point to be made is that the user interface of an application will often make or break it.
Although the functionality that an application provides to users is important, the way in which it provides that functionality is just as important. An application that is difficult to use won’t be used.
It won’t matter how technically superior your software is or what functionality it provides, if user’s don’t like it they simply won’t use it. Hence it is important not to underestimate the value of user interface design.
Interface design is important for several reasons:
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The more intuitive the user interface the easier it is to use, and the easier it is to use the cheaper it is.
The better the user interface the easier it is to train people to use it, reducing your training costs. The better the user interface the less help people will need to use it reducing your support costs. Why bother with HCI?
Developers should bother with HCI in order to:
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Avoid human or machine error

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Make the system error free

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Make money.

The whole point of interface design is to produce systems that are easy to learn and which allow users to work efficiently and comfortably.

Users of Computer Systems
Sometimes back, computer users were only experts users who required little or no interface. With the advancement in both hardware and software together with emergence of new types of computers e.g. PC e.t.c., new types of users also emerged and this lead to demands for easier to understand and use interfaces.
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Users of any computer systems can be classified into the following broad categories:
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Expert Users: People with in-depth knowledge of the system who use it virtually all the time.
They are not necessarily computer specialists, but know the system inside out. For example, an experienced secretary who has been using the same word processor for five years. When designing an interface for experts, it is necessary to workout what actions they perform frequently and provide keystroke shortcuts.

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Novice Users: We are all in this category at some stage. Those who haven’t used the system at all before, or only very superficially. For example, computing students who haven’t used a particular package before. These users benefit a lot form use of menus and suitable training manuals. 

Occasional Users: The vast majority of us. Such users often use a system quite regularly, but only for a limited range of tasks. Occasional users can be like experts for that range of tasks, but like novices for all other tasks. Examples are teachers, managers, lawyers etc.

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Users with Special Needs: Many users with severe disabilities successfully use computer systems that have been specially adapted, for example blind users can use speech recognition and speech synthesis to enable them to use computers. Visual Display Units and keyboards meet the needs of the hearing impaired.

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The ‘Older Users’: Computer era came about when they were already adults. They are characterized by short memory performance and technophobia i.e. reluctant to interact with machines. Interface designers needs to consider them and ensure: o That instructions are supportive other than challenging. o That tutorials have a comparison with older systems. o That use of unusual tools such as mouse scrolling are explained. o That no memory work is encouraged.

USER INTERFACE EVOLUTION
Human-computer interfaces have come a long way since the early days when computer users typed line after line of computer jargon using green text on black screens. This was clearly an interface that only a technologist could love - the rest of us simply had to put up with it if we wanted or had to use a computer. It was clear to some people that significant improvements would be needed in order to achieve the increase in productivity that was being promised through the use of computers.
This awareness led to advances that made the interface more visual using techniques such as menus to ease the burden on users' memories. But the human-computer interface was still comparatively in the dark ages - each application had its own unique interface and there was little similarity across applications. The computer could still only be used effectively by highly-skilled specialists and enthusiasts who were willing to invest a significant amount of time in learning, and who were willing to put up with the computer's quirky demands and behaviors.
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By the time the modern graphical user interface, or GUI, became available, computer technology was becoming more accessible to businesses and individuals. The GUI interface used computer graphics, little pictures called icons, and the mouse to make using a computer easier. Many applications started to look similar because standard controls, such as menus, buttons, and check boxes were provided by the computer manufacturer. It was easier for application developers to use the standard controls than it was for them to develop their own - so users benefited as well. But even though the basic interface mechanisms were becoming more consistent and easier to use, applications and the overall user environment were becoming more and more complex. A word processor could be used not only for writing documents, but could also include spreadsheet data, charts, and drawings. Users were no longer limited to running one application at a time - they could run several in separate windows that overlapped on the display.
In the late 1980's, the HCI group at IBM recognized that users would be overwhelmed by these new capabilities, and that the computer itself was doing little to help them manage several things at once. This recognition led to the development of the object-oriented user interface, or OOUI, a style of interface that is becoming popular today in such systems as Microsoft's Windows 95 and
IBM's OS/2 Warp. An OOUI allows users to focus on the information they need to do their work, and it hides many of the traditional aspects of using a computer that users don't need or want to worry about.
Where is this evolution leading? To be fully embraced by the general population and become a bonafide consumer product, the evolution must take the computer through some further steps to make it even more simple and natural to use. One major factor will be the presentation of information and computer capabilities that resemble what users see and experience in the realworld. Users will interact with telephones, fax machines, and writing tablets on the computer display that look and behave very much like their real-world counterparts, while at the same time providing additional capabilities that aren't possible in the real-world. Users will visit places presented using 3D graphics and virtual reality techniques. They will visit libraries and historical sites, and chat with friends and colleagues throughout the world, all from the comfort of their office, living room, or hotel room. Instead of using cumbersome and unfamiliar computer-oriented devices, users will interact with computers using natural human-oriented techniques, such as writing and speaking. And the computer will exhibit characteristics of personality that will make it seem more friendly and pleasant to work with.
This evolutionary advancement is being driven by the fast-growing technology of the personal computer, and increasing demands from users that the computer match their way of thinking, rather than the other way around. Computers are becoming more a part of everyday life. As a result, we recognize that the user interface is one of the most critical elements of consumer acceptance. Please take a few moments and visit some of our other web pages to learn more about IBM's vision and our approach to making your experience using a computer both productive and enjoyable.

DISCIPLINES CONTRIBUTING TO HCI
The following disciplines have made significant contributions to HCI:
Ergonomics or human factors: The purpose of ergonomics or human factors is to define and design tools and various artifacts for different work, leisure and domestic environments to suit the capacities and capabilities of users.
Cognitive psychology: Psychology is concerned with understanding human behaviour and the mental processes that underlie it. To account for human behaviour, cognitive psychology has adopted the notion of information processing. Everything we see, feel touch, smell and do is couched in terms information processing. Thus cognitive psychology provides knowledge about the capabilities and limitations of users.
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Social and organizational psychology: Social psychology is concerned with studying the nature and causes of human behaviour in a social context. There are four core concerns of social psychology: 
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The influence of one individual on another person’s attitudes and behaviour,
The impact of a group on its member’s attitude and behaviour,
The impact of a member on a group’s activities and structure,
The relationship between the structure and activities of different groups.

The role of social organizational psychology is to inform designers about social and organizational structures and about how the introduction of computers will influence working practices.
Artificial intelligence: Artificial intelligence (AI) is concerned with the design of intelligent computer programs which simulate different aspects of intelligent human behaviour.
Linguistics: This is the scientific study of nature and development of society and social behaviour.
Software engineering: Engineering is an applied science which relies heavily of model building and empirical testing. Engineering essentially takes the findings of science and utilizes them in the production of artifacts.
Design: The process of developing a product, artifact or system; or a representation of the product.

Sociology

Social an organizational Psychology

Ergonomics and human factors Artificial intelligence Linguistics

HCI
Engineering
Cognitive psychology Design

Computer science Figure 1.1 The disciplines contributing to HCI

USER INTERFACE DESIGN PRINCIPLES
In these days of mass computing the ease of use of a software product is one of its most important features. People of all levels of skill and experience will be using software. To get the most out of
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an application they must be able to carry out the necessary tasks with the minimum of fuss. They should also be able to discover how to carry out new tasks.
The development of the user interface for a software system involves taking into account many considerations, broad design goals and an aggressive work schedule. With an exception of some embedded software and operating system code, the success of a software product is determined by the humans who use the product. Designing modern user interface requires an in-depth knowledge and understanding of various cognitive and mental characteristics of human beings.

Some of the considerations which a user interface designer must take into account are:
 Human factors e.g Limited memory, prejudices etc
 Needs and expectations of the system users..
 Knowledge and experiences of the system users.
 Capabilities of the system users.
Hence during the design process, potential users should be involved in order to factor out the design process. It is impossible to judge user interface from an abstract description. In today’s software industry, prototyping methodology has proved that it can help manage the increasing complexity of user interface design process.
The methodology entails creating/implementing an initial prototype and exposing to user and taking the resulting feedback to improve the initial prototype design. The process is repeated until an adequate system design which satisfies the users is produced. It is an iterative analysis technique in which potential users are actively involved in the mocking up of system designs. The aim of a prototype is to show users the possible design(s) for user interface of an application.
User Interface design principles.
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User familiarity

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User interface consistency

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Minimal surprise

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Recoverability

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User guidance

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7. Personalization

Versatility

8. Affinity
9. Simplicity
10. Support
11. Obviousness

12. The Principle of Focus
13. Satisfaction
14. The Principle of Shortcuts
15. Minimize the Burden on the
User’s Memory.

1. User Familiarity
Familiar terms and concepts, which are drawn from the experience of the potential class of users, should be used. For example, a system designed for use by secretarial staff, the objects manipulated should be letters, documents, diaries; folders etc. Operations might be file, retrieve, index, discard and so on.

2. User Interface Consistency
Consistency basically means that the same thing is done in the same way in similar situations and comparable operations should be activated in the same way. It means that, system
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commands and menus should have the same format, parameters should be passed to all commands in the same way, and command punctuation should be similar. Consistent interfaces reduce user-learning time. Knowledge learnt in one command or application is applicable in other parts of the system. The same principle should also be observed across sub-systems.
3. Minimal Surprise
Users should never be surprised by the behaviour of a system. As a system is used, users build a mental model of how the system works. If an action in one context causes a particular type of change, it is reasonable to expect that the same action in a different context will cause a comparable change. If something completely different happens, the user is both surprised and confused.
Interface designers must therefore ensure that comparable actions must have comparable effects.
4. Recoverability
The Interface should include mechanisms to allow users to recover from their errors. Users inevitably make mistakes when using a system. However, these mistakes can be minimized using menus, but mistakes can never be completely eliminated. The interface should contain facilities allowing users to recover from their mistakes. These can be of two kinds:
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Confirmation of Destructive Actions: If a user specifies an action, which is potentially destructive, he or she should be asked to confirm that this is really what is intended before any information is destroyed.

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The Provision of an Undo Facility: Undo restores the system to a state before the action occurred. Many levels of undo are useful as users don’t always recognize immediately that a mistake has been made.
In practice, this is expensive to implement. Most systems therefore only allow the last command issued to be “Undone”.

5. User Guidance
Interfaces should have built in user assistance or help facilities. These should be integrated with the system and should provide different levels of help and advice. Levels should range from basic information on getting started with the system to a full description of the system facilities. These help facilities should be structured; users should not be overwhelmed with information when they ask for help.
6. Versatility: Support alternate interaction techniques
Allow users to choose the method of interaction that is most appropriate to their situation.
Interfaces that are flexible in this way are able to accommodate a wide range of user skills, physical abilities, interactions, and usage environments.
Each interaction device is optimized for certain uses or users and may be more convenient in one situation than another. For example, a microphone used with voice-recognition software can be helpful for fast entry of text or in a hands-free environment. Pen input is helpful for people who sketch, and mouse input works well for precisely indicating a selection. Alternative output formats, such as computer-generated voice output for foreign language instruction, are useful for some purposes. No single method is best for every situation.
Users should be allowed to switch between methods to accomplish a single interaction. For example, allow the user to swipe-select using the mouse, then to adjust the selection using the
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keyboard. At the same time, users should not be required to alternate between input devices to accomplish what they perceive as a single step or a series of related steps in a task. For example, it would be tedious to require the use of a mouse for scrolling while editing text from the keyboard.
Users should be able to complete an entire useful sequence through the same input device.
Providing a range of interaction techniques recognizes that users are individuals with different abilities and situations. The differences include disabilities, preferences, and work environments.
7. Personalization: Allow users to customize
The interface should be tailorable to individual users' needs and desires. No two users are exactly alike. Users have varying backgrounds, interests, motivations, levels of experience, and physical abilities. Customization can help make an interface feel comfortable and familiar.
Personalizing a computer interface can also lead to higher productivity and user satisfaction. For example, allowing users to change default values can save them time and hassle when accessing frequently used functions.
In an environment where multiple users are using a shared machine, allow the users to create their own system personality and make it easy to reset the system. In an environment where one user may be using many computers, make personalization information portable so the user can carry that
"personality" from one system to another.
8. Affinity: Bring objects to life through good visual design
The goal of visual design in the user interface is to surface to the user in a cohesive manner all aspects of the design principles. Visual design should support the user model and communicate the function of that model without ambiguities. Visual design should not be the "icing on the cake" but an integral part of the design process. The final result should be an intuitive and familiar representation that is second nature to users.
The following are visual design principles that promote clarity and visual simplicity in the interface: 
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Subtractive design - reduce clutter by eliminating any visual element that doesn't contribute directly to visual communication.
Visual hierarchy - by understanding the importance of users' tasks, establish a hierarchy of these tasks visually. An important object can be given extra visual prominence. Relative position and contrast in color and size can be used.
Affordance - when users can easily determine the action that should be taken with an object, that object displays good affordance. Objects with good affordance usually mimic real world objects.

Visual scheme - design a visual scheme that maps to the user model and lets the user customize the interface. Do not eliminate extra space in your image just to save space. Use white space to provide visual "breathing room."

9. Simplicity: Don't compromise usability for function

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Keep the interface simple and straightforward. Users benefit from function that is easily accessible and usable. A poorly organized interface cluttered with many advanced functions distracts users from accomplishing their everyday tasks. A well-organized interface that supports the user's tasks fades into the background and allows the user to work efficiently.
Basic functions should be immediately apparent, while advanced functions may be less obvious to new users. Function should be included only if a task analysis shows it is needed. Therefore, keep the number of objects and actions to a minimum while still allowing users to accomplish their tasks.
10. Support: Place the user in control and provide proactive assistance
To give users control over the system, enable them to accomplish tasks using any sequence of steps that they would naturally use. Don't limit them by artificially restricting their choices to your notion of the "correct" sequence.
The system should also allow users to establish and maintain a working context, or frame of reference. The current state of the system and the actions that users can perform should be obvious.
Users should be able to leave their systems for a moment or a day and find the systems in the same familiar state when they return. This contextual framework contributes to their feeling of stability.
Most users perform a variety of tasks, being expert at some and novice at others. In addition to providing assistance when requested, the system should recognize and anticipate the user's goals, and offer assistance to make the task easier. Ideally, assistance should provide users with knowledge that will allow them to accomplish their tasks quickly. Intelligent assistance is like the training wheels on a bicycle - at some point, most users will want to take them off and go forward on their own. The assistance should allow them to become independent at some point when they choose to be so.
11. Obviousness: Make objects and their controls visible and intuitive
Where you can, use real-world representations in the interface. Real-world representations and natural interactions (direct action) give the interface a familiar look and feel and can make it more intuitive to learn and use. Icons and windows were early attempts to draw on user experiences outside the computing domain. As we move toward real-world representations, reliance on such computer artifacts should decline.
In an object-oriented interface the objects and concepts presented to users parallel familiar things from the real world; for example:
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Trash can - when we throw things away we usually use some type of trash receptacle or
"trash can". An object on the desktop displayed as a trash can communicates to users that it is a place for discarding things. It should look like the real object rather than like an abstract container, and the user should be able to show its contents in a meaningful way.

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Telephone - the actions we take with telephones are so familiar to most of us that they require little thought. A telephone object on the desktop indicates to users that it will allow them to perform phone-related tasks, and users will expect it to behave like the real thing.

The controls of the system should be clearly visible and their functions identifiable. Visual representations provide cues and reminders that help users understand roles, remember relationships, and recognize what the computer is doing. For example, the numbered buttons on the telephone object indicate that they can be used to key in a telephone number.
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Allow users to interact directly with objects and minimize the use of indirect techniques.
Identifying an object and doing something with it (like picking up the handset of a phone to answer it) usually are not separate actions in the real world. Likewise, with direct action techniques, explicit selection is not necessary because selection is implicit in the actions users take with objects. Real-world 3D interfaces are especially conducive to direct interaction.
12. Encouragement: Make actions predictable and reversible
A user's actions should cause the results the user expects. In order to meet those expectations, the designer must understand the user's tasks, goals, and mental model. Use terms and images that match users' task experience, and that help users understand the objects and their roles and relationships in accomplishing tasks.
Users should feel confident in exploring, knowing they can try an action, view the result, and undo the action if the result is unacceptable. Users feel more comfortable with interfaces in which their actions do not cause irreversible consequences.
Even seemingly trivial user actions, such as deselection or moving objects, should be reversible.
For example, a user who spends several minutes deliberating and selecting individual files to be archived from a group will be very upset if all the files are accidentally deselected and the deselection cannot be undone.
Avoid bundling actions together, because the user may not anticipate the side effect. For example, if a user chooses to cancel a request to send a note, only the send request should be cancelled. Do not bundle another action, such as deletion of the note, with the cancel request. Rather than implementing composite actions, make actions independent and provide ways to allow users to combine them when they wish.
13. Satisfaction: Create a feeling of progress and achievement
Allow the user to make uninterrupted progress and enjoy a sense of accomplishment. Reflect the results of actions immediately; any delay intrudes on users' tasks and erodes confidence in the system. Immediate feedback allows users to assess whether the results were what they expected and to take alternative action immediately. For example, when a user chooses a new font, the font of all applicable text, or of sample text, should change immediately. The user can then decide if the effect is what was desired and, if not, can change it before switching attention to something else.
Offer a preview of the results of an action when it would be inconvenient for a user to apply the action and then reverse it. For example, if a user wants to bold, underscore, and use helvetica font in certain places throughout a document, provide a sample part of that document with those changes applied, allowing the user to decide if that is the right action to take. This saves the user a lot of time by not having to reverse the action that's been applied to an entire document and enhances the user's confidence in the system.
Avoid situations where users may be working with information that is not up-to-date. Information should be updated immediately or refreshed as soon as possible so that users are not making incorrect decisions or assumptions. If, for some reason, the results of a refresh cannot be displayed immediately, the situation should be communicated to users. This becomes especially important in networked environments where it is more difficult to maintain state between networked systems dynamically. For example, most Web browsers display a completion percentage in the information area so that users know the progress of the graphics loading process.
14. Availability: Make all objects available at all times
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Users should be able to use all of their objects in any sequence and at any time. Avoid the use of modes, those states of the interface in which normally available actions are no longer available, or in which an action causes different results than it normally does.
Modes restrict the user's ability to interact with the system. For example, one of the most common uses of modes in menu-driven systems is the modal dialog box (such as "Print" and "Save as") used to request command parameters. Modal dialogs tend to lock users out of their system; to continue, users must complete - or cancel - the modal dialog. If users need to refer to something in an underlying window to complete the dialog, they must cancel the dialog, access the information they need and re-invoke the dialog.
15. Safety: Keep the user out of trouble
Users should be protected from making errors. The burden of keeping the user out of trouble rests on the designer. The interface should provide visual cues, reminders, lists of choices, and other aids, either automatically or on request. Humans are much better at recognition than recall.
Contextual and hover help, as well as agents, can provide supplemental assistance. Simply stated, eliminate the opportunity for user error and confusion.
Users should never have to rely on their own memory for something the system already knows, such as previous settings, file names, and other interface details. If the information is in the system in any form, the system should provide it.
Two-way communication may be necessary at times to allow users to clarify or confirm requests, or to remedy a problem. In the past, many interfaces have treated communication with users as primarily one-way, computer-to-user. The communication should be interactive - as rich in presentation and interaction capabilities as the rest of the interface. It should present relevant information, provide access to related information and help, and allow users to make task-specific decisions to continue. For instance, spell check, as designed in some systems, highlights potentially misspelled words as users work, allowing them to either select a new word or continue to work until they reach a point where they can go back and validate the potentially misspelled words. Adopt the following design perspective: users know what they want to accomplish, but sometimes they find it difficult to express their desires using the objects and actions provided, and the system is unable to recognize their request. Two-way communication may be used to help users reach their goals.
The principles emphasize that the interface design process should be user centred. Computer users are trying to solve problems using the computer yet many existing systems do not take user needs and limitations into account. The designer should always bear in mind that system users have a task to accomplish and the interface should be oriented towards the task. Users may participate directly in the design process as team members. This approach has been used with some success in
Scandinavia in what is called participatory design.

HUMAN FACTORS IN HCI
Information technologies are used in the real world in offices, homes, factories, and industries.
Human factors work is concerned with the design, usability, learnability, and functionality of systems designed for human use. Unless human characteristics are considered when designing or implementing technologies, the consequences can be errors and a lack of human productivity.
Human factors workers are concerned with important health and safety issues in work environments that include technology.
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Human factors work involves assessing how something is used to see if it can be made quicker, safer, and more productive, looking at mistakes that are made when using technologies to see how they could be prevented, and assessing which tasks can effectively be performed by humans or machines. Historically, many technologies have not been designed with users in mind. Many technologies do not fit users' tasks. Technology systems need to be built to effectively support human tasks. Failing to design and develop information technologies with user characteristics in mind can lead to a lack of system functionality, increase in user dissatisfaction, and increase in ineffective work practices.
Poorly designed and inappropriately placed interfaces can decrease worker efficiency, increase poor customer service, and increase costs.
Human factors workers examine individual differences in a technology-user's behavior and performance that have design implications. Workers with human factors training understand the importance of looking at both people and systems, as they work together. Information technology must account for human levels of attention, learning, communication styles, and memory.
Human factors workers integrate knowledge from multiple disciplines to design better technologies. Research from engineering, anthropology, sociology, social psychology, mathematics, cognitive psychology, and linguistics is used in human factors work. Human factors work and research involves the collection of the data and the evaluation of different designs. The following factors affect design - physical, perceptual, cognitive, social, and historical. The results of human factors work are important and applied in many different industries and work environments, such as the design of computers, cars, airplanes, industrial machinery, military vehicles, office environments, consumer products design, and manufacturing.

Human Cognitive Capabilities
Cognition is the process by which we gain knowledge. The processes which contribute to cognition include: • understanding
• acquiring skills

• remembering
• creating new ideas

• reasoning

• attending

• being aware

A key aim of HCI is to understand how humans interact with computers, and to represent how knowledge is passed between the two. The basis for this aspect of HCI is the science of cognitive psychology. The results of work of cognitive psychologists provide many lessons which can be applied in the design of computer interfaces. These results are expressed in the form of cognitive frameworks.

Human factors workers must also take account of human cognitive capabilities, such as memory, attention, and learning ability that vary between users. Humans have four types of memory: iconic, short-term, working, and long-term.
1. Iconic memory: This very short term memory includes images left in memory when a user closes their eyes.
2. Short-term memory: A temporary memory store where information decays over time.
3. Working memory: A temporary memory store that includes refreshing or reusing the information. 4. Long-term memory: A memory that is permanently encoded with longer more permanent memories. 5. In addition, memory can be classified as declarative memories that include facts or statements about the world and procedural memories that are used to perform procedures.
More specifically, implicit memories are not reportable and explicit memories can be
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reported. Human factors workers must also consider human learning abilities and how to design information technologies to support different learning styles.
Human factors workers must keep human limitations in mind when they are designing technologies. For example, if a person needs to enter a phone number in their Contacts, they store the number in short term memory. The short term memory limitation is generally "five plus or minus two" items, just enough for the typical phone number.
Human cognitive capabilities should be considered in the design of a system. For example, human cognitive capabilities should be considered in the design of a web search history application, so that when the user is searching the web and they use the search history to help them remember what they previously had searched, the results are successful. Human factors work influences the design of systems. An example is the navigation system in a car assisting the user in successfully reaching their destination.
Human factors workers are concerned with vital issues in the technology workplace. Human limitations, the shape of the human body, and how the shape of the human body influences the design of systems must be considered. If industries, including airlines and nuclear power plants, do not consider human factors issues, then the public's safety is jeopardized.
Human computer interaction (HCI) is the study of human interaction with computer interfaces and the development of computer based interfaces to support effective user-computer tasks and interaction. Human computer interaction work involves the detailed study of users' tasks, goals, and behaviors when using computer systems and interfaces.
HCI workers develop new computer applications and interface, and then test and evaluate new interactive computer devices and interfaces. For example, when designing a Web search engine interface, an HCI worker seeks to understand how users look for information on the Web, how users decide what action to take, and what information do users need to plan a strategy for performing the task.
HCI workers must decide what information users need to perform a HCI task. They also consider the cognitive effort involved in a task (the number of mental transformations), how to display information on a computer interface so that it is most comprehensible and perceptible to the user.
For example, HCI workers examine how to design more effective word processors and Web search engines. HCI Model: Foley
Foley (1980) provides a comprehensive HCI model that includes the following four levels:
The first stage is the conceptual level understanding of the user's mental model of the HCI task.
Users may have different mental images of the HCI task. For example, users have very different mental pictures of the Web. If you ask people to draw a picture of the Web, these pictures might include the following very different representations: hierarchy, telecom, library system, network, and 3-D web. Another example is that some users equate using a word processor with a typewriter interaction; a computer keyboard is similar to a typewriter keyboard.
The semantic level understanding includes the meaning of the user's input to the computer and the computer's output to the user. The input-output feedback loop between user and system only works effectively if the computer understands the user's input and the user understands the system's output. This can be a problem if the system's output is culturally based. For example, Americans
15

understand the "trash" icon, but the British use the word garbage and may not understand the
"trash" icon.
In the syntactic level, there is an understanding of how the words used are assembled into meaningful sentences that instruct the computer to perform a certain task. HCI works well when users can express their needs in meaningful sentences to the computer. For example, users often have problems expressing their information need to a Web search engine.
The fourth level, the lexical level, includes understanding user's mechanisms when structuring their interaction with the computer. A user's interaction with a computer is structured by the person who developed the interface. If the interface does not allow the user to structure their interaction in a user friendly way, the system interaction may not be satisfactory. For example, when looking for information, people often ask questions of other people. Many Web search engines do not allow the user to ask the computer a question in natural human language or conversation style.
Norman (1988) provides the following goal-oriented staged model of user's interaction with a computer: 1. Forming the goal of the HCI interaction: User's interact with a computer to solve a problem or achieve a goal. For example, a user's goal may be to find information about motor boats by using a Web search engine.
2. Forming the intention of the HCI interaction: Having established a goal for their interaction with a computer, users must form an intention to use the computer.
3. Specifying the HCI action to be performed: An interface must clearly specify the actions users need to perform. For example, if the user does not clearly understand the correct commands or instructions to conduct an interaction with a Web search engine, their HCI interaction may fail.
4. Executing an action with the computer: A user's HCI interaction must be error free and achieve the correct action. For example, the interface must provide effective help systems.
5. Perceiving the systems state through feedback: The computer output must be in a form that the user is able to see the feedback. System responses must be visible and readable by the user. The size of text and images must be large enough to read.
6. Interpreting the systems state through feedback: The computer output must be in a form that the user is able to understand the feedback. System responses must be comprehensible and understandable by the user. Many computer responses to users input are incomprehensible and are often ignored by users.
7. Evaluating the systems output: Users must be able to evaluate the systems output correctly and effectively. For example, most Web search engines display the results of a user's query as a list of Web sites. Frequently, users do not understand the structure of this Web site list, and how it is ranked and determined by the system.

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Good HCI Work and Design
Solid HCI work serves as the foundation to obtaining the following results. Good human computer interaction work and design is important for obtaining these measurable outcomes:







Increasing worker productivity
Increasing worker satisfaction and commitment
Reducing training costs
Reducing errors during interface interaction
Reducing production costs

Increase in Worker Productivity, Satisfaction, and Commitment
Good human computer interaction work and design is important for increasing worker productivity.
If workers have problems using computer interfaces, due to poor design, their work effectiveness can be reduced. Effectively designed interfaces that offer customization for users can increase user's work satisfaction. For example, a military fighter plane must have highly effective HCI interfaces to allow pilots to make quick and effective decisions and actions.
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Good human computer interaction work and design is important for increasing worker satisfaction.
Improved interfaces design can lead to increased worker satisfaction and allow users to achieve their work goals.
Good human computer interaction work and design is important for increasing job commitment by reducing worker turnover. Poor quality interfaces can lead to stress and strain on users both mentally and physically. Users may experience sore muscles or eye strain due to poor HCI interfaces and computer design. Workers may leave their jobs if they are dissatisfied with their HCI experience. Reduction in Training Costs, Errors, and Production Costs
Good human computer interaction work and design is important for reducing training costs. Poor
HCI interfaces may require extensive and expensive user training. Good interfaces with effective online or manual training documents and user system guides can help users to master their system interaction quickly. For example, commercial pilots learn to fly airplanes using computer-based cockpit simulators.
Good human computer interaction work and design is important for reducing errors during interface interaction. Effective interfaces and user training can reduce errors in system use. For example, an effective retail interface can reduce the time taken to complete a sale.
Good human computer interaction work and design is important for reducing production costs.
Effective interfaces allow workers to produce better quality products and services. For example, an effective Website can assist users to view products and services offered by companies, including better customer services.

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INTERFACE DESIGN
Many information technology interfaces are poorly designed. Many people are not able to use interfaces effectively due to poor design. Good interface design is important for reducing costs, errors, additional training, and employee turnover; and increasing user satisfaction, productivity, and quality products and services.
Good interface design requires diverse knowledge of systems design processes and user characteristics, including:












Users' physical characteristics, limitations, and disabilities.
Speed and efficiency needs.
Reliability issues.
Security concerns.
Level of usability and functionality required.
Frequency of product use.
Users' past experience with same or similar product.
Level of cognitive or mental effort required from the user.
Users' tolerance for error.
Users' patience and motivation for learning.
Cultural and language aspects.

Good Interface Design
Good interface design requires diverse knowledge of systems design processes and user characteristics, including:














Users' physical characteristics, limitations, and disabilities: Interface designers need to understand the characteristics of their users. For example, an Automatic Teller Machine
(ATM) interface must be accessible by elderly, young, and disabled bank customers.
Speed and efficiency needs: Many interfaces need to be quickly accessible and effective.
For example, military pilots must have cockpit interfaces that allow quick and efficient interaction. Reliability issues: Interfaces that affect human lives need to provide reliable and readable information. For example, if an interface is provided information in a nuclear power plant system or a hospital operating room, the data quality and presentation needs to be accurate and reliable.
Security concerns: Interfaces must have effective security and access mechanisms as required by an organization. For example, a bank Automatic Teller Machine (ATM) must allow bank customers to securely access their accounts and also keep out potential hackers.
Level of usability and functionality required: Interfaces for users with little computing experience are more simply structured than interfaces designed for expert level users. For example, many interfaces offer advanced options and features for more expert users.
Frequency of product use - Interfaces in high use computer systems need to be more reliable and effective to cater for fast interaction and a variety of users. For example, a bank
Automatic Teller Machine (ATM) is used by hundreds of customers every day. The interface must allow for quick and effective interaction.
Users' past experience with same or similar product - Many interfaces and systems provide similar features. For example, many bank Automatic Teller Machines (ATMs) provide
19








identical functions and use similar banking terminology. The concepts of "withdrawal" and
"deposit" that appear on ATM interfaces are familiar to bank users.
Level of cognitive or mental effort required from the user - Many complex computer packages require a high level of financial or accounting knowledge
Users' tolerance for error - Many interfaces allow users to complete actions with serious consequences when errors occur. For example, in a hospital emergency room, the medical computer interfaces need to be accurate, reliable, and without error, or patients may die.
Users' patience and motivation for learning - Many interfaces are designed to allow users effective interaction with little learning required. For example, bank Automatic Teller
Machines (ATMs) are simple menu systems that are designed to allow quick and easy learning. Cultural and language aspects - Interface designers must take account of users' cultural and language differences. For example, many interfaces that are designed for users in the multicultural United States society provide interaction in English, Spanish, Chinese, or other languages.

USER CENTERED DESIGN

User centered participatory design involves the inclusion of users input into each phase of the user centered design process, including the user walkthrough and approval of each interface feature of a systems prototype.
User centered design involves the identification and consideration of relevant human factors in the design, evaluation, and implementation of information technology interfaces.
Displays should be readable (consider size, position, and ambient lighting) with differentiate and consistent displays (by shape, color, position, and size) that are compatible with the task to be performed. HCI Design Process
The steps in the HCI design process can include the following steps:
1. Analyzing the users and determining their needs.
2. Drafting an initial design based on the users' needs analysis.
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3. Testing the initial design with users in an HCI testing laboratory or in a real user work environment. 4. Developing a prototype system based on the initial design and users' feedback.
5. Testing the prototype system with users in an HCI testing laboratory or real user work environment. 6. Designing and refining each specific interface and screen.
7. Testing the interface with users in an HCI testing laboratory or a real user work environment. 8. Refining the interface based on users' feedback.
9. Implementing the interface.

USABILITY
An important part of the user centered design process is the incorporation of usability testing during both the design and evaluation stage of the systems or interface development. Usability refers to how easy an information technology is to use. Useful information technologies must be functional, useful, and learnable by humans.
Usability testing is important for:
1. Demonstrating the strengths and weaknesses of a design process and product. Usability testing includes collecting data that can be used to improve and redesign the interface.
2. Evaluating the overall design and specific system features. For example, HCI workers may test if users prefer a command line or menu interface.
3. Assessing the functionality of the system for a particular organization or set of users.
4. Validating the effectiveness and efficiency of the system, including potential productivity gains. 5. Providing the system designers with feedback on user satisfaction.
6. Identifying errors or mistakes in the systems design.

Usability Testing
Usability workers systematically and iteratively test each aspect of the system to improve systems design. Usability testing is a key part of iterative design techniques.
Systems are tested to see whether they fulfill the user's goals and provide feedback to the user on their actions taken and results. Every system or interface developed by industry involves some level of usability testing. Many industry accidents occur due to poorly designed information technologies. The goal of usability testing is also to identify users' problems with the system, enable the users to provide the systems designers with feedback, and evaluate the performance of the system.

Formative and Summative Evaluation
Usability testing can occur at any time during the design process. User testing should be done early and often with real users.
There are different approaches and terms relating to user testing:

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Formative evaluation: This occurs in order to assist IT designers in forming and refining their designs. Specific problems are identified during the design process. This is part of the iterative design process. The formative evaluation stage could include a think-aloud session where the user verbalizes their thoughts, choices, and questions to the evaluator. Evaluation is more likely to be done in person with direct observation. Video or audio recording of the user's interactions may be done. Summative evaluation: This follows usability testing. The overall effectiveness and impact of the system is summarized. This may include a test between two or more alternatives. Statistical differences between features may be summarized and compared. Evaluation may be done remotely.
Alpha Testing: This usually is internal testing. The prototype that is developed is evaluated by internal users.
Beta Testing: This is usually available to external users. The prototype is made available to be evaluated by external users.

Usability Testing Tasks
Usability testing tasks include:
1. Analyzing users' interaction with the system, for example, users' keystrokes and interaction history, eye movements, and patterns of use.
2. Conducting experiments in which users perform system interaction tasks and think aloud
(talk out loud about their actions and tasks) as they interact with the system.
3. Measuring the time users take per task, their error rates, and their level of satisfaction with the system.
4. Recording users' interaction with the system via paper forms, audio taping, or video taping to examine users' problems, errors, or interaction effectiveness.
5. Surveying users using a questionnaire or interview regarding their satisfaction with the system. Usability testing includes the ethical concerns of respecting a user's mental and physical well-being and privacy. Evaluation workers must obtain the informed consent of volunteer participants before beginning usability testing. Usability workers must also be concerned not to bias users when conducting evaluation testing.
NB. Pervasive computing
Pervasive computing, also known as ubiquitous computing is the trend towards increasingly ubiquitous connected computing devices in the environment, a trend being brought about by a convergence of advanced electronic - and particularly, wireless - technologies and the Internet.
Pervasive computing devices are not personal computers as we tend to think of them, but very tiny
- even invisible - devices, either mobile or embedded in almost any type of object imaginable, including cars, tools, appliances, clothing and various consumer goods - all communicating through increasingly interconnected networks. In these devices, the computer interface moves away from the desktop and the interface

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PERCEPTION AND REPRESENTATION THEORIES
Perception
An understanding of the way humans perceive visual information is important in the design of visual displays in computer systems. Several competing theories have been proposed to explain the way we see. These can be split into two classes: constructivist and ecological.

Constructivist theorists believe that seeing is an active process in which our view is constructed from both information in the environment and from previously stored knowledge.
Perception involves the intervention of representations and memories. What we see is not a replica or copy; rather a model that is constructed by the visual system through transforming, enhancing, distorting and discarding information.
Ecological theorists believe that perception is a process of ‘picking up” information from the environment, with no construction or elaboration needed. Users intentionally engage in activities that cause the necessary information to become apparent. We explore objects in the environment.

The Gestalt Laws of perceptual organization (Constructivist)
The Gestalt approach emphasizes that we perceive objects as well-organized patterns rather than separate component parts. The Gestalt psychologists were constructivists. The focal point of Gestalt theory is the idea of "grouping," or how we tend to interpret a visual field or problem in a certain way. Affordances (Ecological)
The ecological approach argues that perception is a direct process, in which information is simply detected rather than being constructed. A central concept of the ecological approach is the idea of affordance . The possible behaviour of a system is the behaviour afforded by the system. A door affords opening, for example. A vertical scrollbar in a graphical user interface affords movement up or down. The affordance is a visual clue that suggests that an action is possible.
When the affordance of an object is perceptually obvious, it is easy to know how to interact with it.
Norman's first and ongoing example is that of a door. Some doors are difficult to see if they should be pushed or pulled. Other doors are obvious. The same is true of ring controls on a cooker. How do you turn on the right rear ring?
"When simple things need labels or instructions, the design is bad."
Affordances in Software
Look at these two possible designs for a vertical scroll bar. Both scrollbars afford movement up or down. What visual clues in design on the right make this affordance obvious?

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Perceived Affordances in Software
The following list suggests the actions afforded by common user interface controls:
• Buttons are to push.
• Scroll bars are to scroll.
• Checkboxes are to check.
• List boxes are to select from. etc.
In some of these cases the affordances of GUI objects rely on prior knowledge or learning. We have learned that something that looks like a button on the screen is for clicking. A text box is for writing in, etc. For example, saying that a button on a screen affords clicking, whereas the rest of the screen does not, is inaccurate. You could actually click anywhere on the screen. We have learned that clicking on a button shaped area of the screen results in an action being taken.
Link affordance in web sites
It is important for web sites users to know what objects on the page can be clicked to follow links.
This is known as link affordance. The following lists give some guidelines for improving link affordance: Text links
• Do use blue underlined text for most links
• Do use underlined headers as links
• Do use words in a left-justified list as individual links
• Do use bullets, arrows or some other indicator in front of certain text links
• Do use "mouse-overs" appropriately and with care
• Do use page location to help communicate that an item is clickable
- Left or right margins
- Top or bottom of the page
• Do use the term "click here" when appropriate
Graphical links
• Do use meaningful words inside graphical links
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- Target locations (Home, Back to Top, Next
- Common actions (Go, Login, Submit, Register)
• Do use graphical "tabs" that look like real-world tabs
• Do use graphical buttons that look like real-world pushbuttons
• Do use clear, descriptive labels inside tabs and pushbuttons
• Do make all company logos clickable (to the home page)

INFLUENCE OF THEORIES OF PERCEPTION ON HCI
The constructivist and ecological theorists fundamentally disagree on the nature of perception.
However, interface and web designers should recognise that both theories can be useful in the design of interfaces:
• The Gestalt laws can help in laying out interface components to make use of the context and prior knowledge of the user
• paying careful attention to the affordances of objects ensures that the information required to use them can easily be detected by the user.

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HUMAN COMPUTER INTERACTION DESIGN/MODELS
Think of the way a craftsman knows the tools and materials he will be using to put something together. The same thing goes for user interface design: you have to know the tools and materials.
For our purposes; the materials are user interface elements and design options on various levels.
Designing user system interactions needs six different levels:


System services



Conceptual model and metaphor



Dialogue structure



Interaction technique



Graphic design



Input/output devices.

The Gulf of Evaluation is the amount of effort a user must exert to interpret the physical state of the system and how well their expectations and intentions have been met.
• Users can bridge this gulf by changing their interpretation of the system image, or changing their mental model of the system.
• Designers can bridge this gulf by changing the system image.
The Gulf of Execution is the difference between the user’s goals and what the system allows them to do – it describes how directly their actions can be accomplished.
• Users can bridge this gulf by changing the way they think and carry out the task toward the way the system requires it to be done
• Designers can bridge this gulf by designing the input characteristics to match the users’ psychological capabilities.
Design considerations:
Systems should be designed to help users form the correct productive mental models. Common design methods include the following factors:
• Affordance: Clues provided by certain objects properties on how this object will be used and manipulated. • Simplicity: Frequently accessed function should be easily accessible. A simple interface should be simple and transparent enough for the user to concentrate on the actual task in hand.
• Familiarity: As mental models are built upon prior knowledge, it's important to use this fact in designing a system. Relying on the familiarity of a user with an old, frequently used system gains user trust and help accomplishing a large number of tasks. Metaphors in user interface design are an example of applying the familiarity factor within the system.

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• Availability: Since recognition is always better than recall, an efficient interface should always provide cues and visual elements to relieve the user from the memory load necessary to recall the functionality of the system.
• Flexibility: The user should be able to use any object, in any sequence, at any time.
• Feedback: Complete and continuous feedback from the system through the course of action of the user. Fast feedback helps assessing the correctness of the sequence of actions.

i)

System Services:

To design the system services means to decide what services the user is going to have available. Of course, this should be based on the tasks and objects found during system analysis. At this stage you don’t want to make low-level decisions about menus, commands or buttons. Instead one should try to identify the objects and tasks that is going to support. The guiding principle here is simply that the services should answer to the users’ needs and support their work as well as possible. ii)

Conceptual Model and Metaphors:

A conceptual model has to do with the general structure of the system. The most frequent types of conceptual models are black boxes, state models, hierarchies and object/action models. What is the point of a conceptual model?

The idea is that the user should be able to understand the system on a general level. If the conceptual model is clear and consistently used in the design, it is easier for users to apply what they have learnt in one part of the system also in other parts of the system.


Black Box Model:

In the black box model, we don’t expect the user to understand what happens inside the system.
All that he or she knows about are inputs and outputs. Users would not have to think about anything but what they are looking for. The disadvantages of this model are:


The users have no opportunity to understand how the domain objects are represented in the system and to gradually learn more about how to use the system.



It is also very hard for the users to understand the reasons for errors in a black-box model.

In summary, a black box model might be applicable for systems supporting a small number of routine tasks, where the users are not expected to develop and learn. In practice, this is very rare.

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

State Model: The system has a number of interaction states. The user goes through the states in order to reach the Goal State. The classic example of a state model is an Automatic Teller machine. When you walk up to the machine, it is an in an initial state where the only action allowed on your behalf is to slide the card into the machine. In the next state, you are expected to enter your personal identification number. Then, you would have a choice of two or three actions, typically to specify an amount of money to withdraw or to press a button to get the balance of the account. State models offer more guidance to the users than black-box models, but it is easy to grow tired with them if you have to use them regularly.



Hierarchical Model: Hierarchical models are typically used if there is a large number of services or transactions available to the users. They tend to be action centred, which means that the hierarchy organizes the user actions rather than the objects.



Object/Action Model: The Object/Action model is based on the idea of modeling the domain objects and the actions the users can carry out upon them. This is typically used in direct manipulation interfaces, where the objects of the application domain are modeled using graphical representations. The user gets access to the services of the system by manipulating these objects and applying functions to them. The actions are defined in terms of what the users should be able to do with the objects. Users would have to learn more about the system to be able to use it but, on the other hand an object/action model gives much better opportunities for the users to develop in their use of the system. Once they have understood how the domain objects are represented in the system, they can learn new actions simply by trying them out. An object/action design also typically leaves the initiative much more with the users, which is considered a good thing.

Metaphor: It is used to describe an analogy to real world things that the users are already familiar with. 

Conversation and Model-World: A conversational system is one where the system acts as a communication partner and talks with the user about the domain objects. In a model world system, the domain objects are modeled in the user interface for the user to act upon. So, black-box and state-model systems are typically conversational; object/action systems typically present a model world.



Analogical Metaphors: The idea here is to design a user interface to take advantage of the user’s previous knowledge of everyday things.

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29

INTERACTION STYLES
The designer of a user interface to a computer is faced with two key issues:


How can information from the user be provided to the computer system?



How can information from the computer system be presented to the user? A coherent user interface must integrate user interaction and information presentation through some common framework such as an interface metaphor.

There are many different types of user interface constructs available:
a)
b)
c)
d)
e)
f)
g)

Command Driven Interfaces
Menu Driven Interfaces
Direct Manipulation Interfaces
User Interface management Systems (UIMS)
Special Purpose Interface
Form Filling Interfaces
Iconic Interfaces.

a) Command Driven Interfaces
It is one of the long-established methods by which users can interact with the computer. A command language is a well-defined verbal language with a syntax regulating the order of commands and arguments. Commands enable the user quickly and simply to instruct the computer what to do.
The first command languages were the commands in operating systems. A special thing in command languages is that they are used in a dialogue-like fashion; the user issues a command and waits for the response. Command driven interface requires the user to have knowledge of the commands and syntax in order to formulate proper commands and therefore suited to experienced users than to beginners. Hence, this type of interface is popular in situations where the end user is a technical person e.g. a
Computer Programmer or a Operator.
This type of interface can be improved by:


The command words used should be VERBS that clearly and unambiguously convey the intended action e.g. PRINT, COPY, DELETE.



Unique abbreviations should be provided for more experienced users e.g. PRI,
COP, DEL. Also the provision of a means by which users may define their own abbreviations.



Consistency: This applies to syntax – the order between command and arguments should be consistent throughout the language.

b) Menu Driven interfaces
In a menu interface, users select one of a number of possibilities to issue a command to the machine. They are action-centered instead of data centered. The main motivation for using menus is the principle “recognition is easier that recall”.
Menus are mostly used to remind the user of available actions, commands or attribute values. 30

Advantages:


The user is presented with a choice and therefore does not need to have remembered any commands. Hence, the interface is suitable for beginners and infrequent users.



Typing effort is minimal.



User errors are minimal. Invalid options can be disabled by the system. Command syntax errors are never made.

Systems that require the user to navigate in a space of information or possible actions can be built exclusively around menus. It is common in this type of systems to structure the menus as a tree.
This makes it possible for untrained users to traverse large collections of information quite quickly if they can understand the grouping on higher levels. Much research has been devoted to the question of breadth versus depth of these menu trees. If menus have many items each, the tree becomes broad and doesn’t need to be as deep. Experiments have shown that a broad and shallow menu tree is preferred by users and also enable them to work faster.
Menus Constructs:


Pull Down Menus: Display the menu title, selecting this “Pull down” the menu for command selection. 

Pop -Up Menus: Are associated with entities such as a field on a form. Selecting the item and then clicking a mouse or pressing a key causes the menu to appear. The options can change to suit the entity with which they associated.
Pop-up menus take up screen space for commands which are rarely used.
Pop-up menus contradict the principle that “Interface should not surprise users”.

b) Direct Manipulation Interfaces
The basic idea in a true direct manipulation interface is that objects in the task domain are represented by interface objects. The user carries out his tasks by manipulating the interface objects. A prototyping example is the operating system of Microsoft-Windows. Objects in the task domain-files, directories, etc. are represented by documents, folders and other objects. The user would select a document and drag it into a folder to carry out the domain task of moving a file into a directory.
The interface objects are chosen to be similar to every day objects in the user’s office environment.
A direct manipulation interface is data centered, which means that the domain objects, or the data of the application, are visible to the user. Actions beyond simple manipulation tasks have to be coded into some sort of visual representation. This is why most direct manipulation interfaces have command buttons or icons and typically also a palette of tools.
An obvious benefit of this visual representation is that the user can see which actions and objects are available without having to remember very much the syntax.
Advantages:



Users feel in control of the computer and are not intimidated by it.
Users learning time is relatively short.
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

Users get immediate feedback on their action. Mistakes can often be detected and corrected quickly. Disadvantages:



The concept of interaction history is harder to realize.



Procedural actions are hard to support in a direct manipulation design e.g. how would you support the action “change all italics to bold” in a direct manipulation word processor.

d) User Interface Management Systems
The aim of a user interface management system is the creation of a means by which a consistent interface with the same “look and feel” can be provided for any number of different applications within the same system. In a full implementation, every user interface will have the desired properties.
Examples of UIMS are the system used on the Apple Macintosh Computer, OSF/MOTIF from the
Open System Foundation and the ”Open Look” system developed by Sun for AT & T.
The UIMS achieves this goal as follows:


The UIMS provides a set of standard facilities for handling the user dialogue. These facilities are available to the programmer as a set of tools. Some tools, called widgets, provide the basic standard components of the interface, such as a facility to display a box on the screen for data entry. 

The UIMS provides some standard software, which manages the way in which each application program uses the interface.
A set of rules governs the way in which various features should appear or behave e.g. there may be a strict rule about how the mouse is to operate, such as:



-

A single click selects an item
A double click activates an item
Dragging the mouse a long with button held down selects all items passed over by the cursor.

Most general-purpose UIMS are based upon windowing systems. Such a system might be built using X-Windows and make use of some kind of WIMP. It is important to realize that, by themselves, Windowing Systems and Interface, like WIMPS do not necessarily provide a satisfactory interface, because there is nothing to prevent such facilities from being used in an inconsistent and poorly organized way. It is the UIMS, which provides and enforces the consistent interface. Apart from the obvious benefits obtained from having a user-friendly interface the use of a UIMS also results in the saving effort in programming and training. The savings in training are most noticeable when users come to learn their second application and discover they can already do lots of things because of its close similarity to the first application they learnt. The price sometimes paid for these benefits is the extra processing load placed upon the computer which may affect performance or require the purchase of more expensive hardware.
e) Special Purpose Computer Interface
There are two main types of Special-Purpose HCI.
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a) A General Purpose Computer – may be used, BUT some parts of the HCI are provided by special hardware and software e.g. the computer may be used to control some industrial process so there may be video monitors in use which simulate the appearance of traditional, precomputerized instrument dials. Another example is the cash-dispensing machine used by banks and building societies.
b) The Computer is embedded inside some special-purpose equipment and is controlled by an interface that is specific to that purpose. The interface used on a digital watch is a good example of such an interface, but not always an example of one that works well judging by the way in which some individuals have problems working out how to adjust their watches. If the interface was really good, there might be no need for and instruction book.
The use of embedded computers within a system should in principle make it easier to
Provide a better user interface. Sadly, this does not always happen.
f) Form Filling Interfaces
This is where the user issues commands by filling in fields in one or more forms displayed on the screen. The difference between menus and forms, is that a menu is a display of alternatives, in which one option or value is discriminated or selected in each cycle, and a form is a display of requirements, in which various options and values are specified and integrated in a single display screen. g) Iconic Interfaces
This is where user commands and system feedback are expressed in graphical symbols or pictograms instead of words. People find images “natural”, because the human mind has powerful image memory and processing capabilities, because the icons can be easily learned and recognized, and because images “can possess more universality than text”, iconic interfaces can “reduce the learning curve in both time and effort, and facilitate user performance while reducing errors”.
Despite the vigorous research examining particular aspects of this diversity of interaction styles and techniques, the area is resistant to simplistic solutions. Thus it has not been possible to show a general superiority among command language, menu, direct manipulation, UIMS, or even special purpose interfaces. The choice of the “best” interaction style is and will remain a complex function of the task, the users who are to carry out this task, the environment with which they will work, and the tools with which they are to do the job.
WINDOWING SYSTEM

A windowing system (or window system) is a component of a graphical user interface (GUI), and more specifically of a desktop environment, which supports the implementation of window managers, and provides basic support for graphics hardware, pointing devices such as mice, and keyboards. The mouse cursor is also generally drawn by the windowing system. A windowing system is a system for sharing a computer's graphical display presentation resources among multiple applications at the same time. In a computer that has a graphical user interface (GUI), you may want to use a number of applications at the same time (this is called task). Using a separate window for each application, you can interact with each application and go from one application to another without having to reinitiate it.
Having different information or activities in multiple windows may also make it easier for you to do your work. 33

The term windowing system is sometimes used to refer to other elements of a graphical interface such as those belonging to window managers or even applications. While on some operating systems the distinction between applications, window managers, and their supporting technologies are blurred, strictly speaking, a windowing system does not include windows themselves.
A windowing system uses a window manager to keep track of where each window is located on the display screen and its size and status. A windowing system doesn't just manage the windows but also other forms of graphical user interface entities.
The X Window System is a cross-platform windowing system that uses the client/server model to distribute services in a network so that applications can run in a remote computer. Users of workstations or terminals using the X Window System don't need to know where the application is located. Apple's Macintosh and
Microsoft's Windows operating systems have their own windowing systems built into the operating system.

From a programmer's point of view, a windowing system implements graphical primitives such as rendering fonts or drawing a line on the screen, effectively providing an abstraction of the graphics hardware from higher level elements of the graphical interface like window managers.
A windowing system enables the computer user to work with several programs at the same time.
Each program runs in its own window, which is generally a rectangular area of the screen. Most windowing systems have basic support of re-parenting which allows windows to overlap, however the ways in which windows interact is usually controlled by the window manager.

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COMPUTER SUPPORTED COLLABORATIVE WORK (ALSO KNOWN AS
GROUPWARE)
Groupware may be defined as hardware, software and processes designed to aid in group related tasks such as basic communication, information sharing, decision making, scheduling/control, and analysis/design. The terms' group and process are the critical elements in the groupware equation.
Also important in the discussion of groupware are the concepts of time and place. Largely a buzzword in the late 1980s and early 1990s, groupware has moved into the mainstream of the knowledge worker's environment. Annual application growth rates in this arena now typically exceed 100%. Groupware is a term that encompasses many different technologies and business process areas. Specific technologies in this arena include electronic mail, digital voice mail systems, text conferencing, videoteleconferencing, collaborative databases, workflow, group decision support systems, and living worlds.
Critical Success Factors
Three major points should be considered as the individual technologies are discussed.
First, the greatest power from groupware is exhibited when the various technologies can be combined with each other, and be integrated within the business processes of the organization.
Second, organizational success in implementing groupware requires a critical application and a critical mass. Groupware requires group work -- the work of all the group, within an application in which they all participate.
And third, the major challenges in the groupware discipline are not technical or economic, but social. It is a very different mode of work, to which we are not accustomed. To insure its success in an organization, management must monitor the use of the technology and take corrective action before the group is "turned off" to its usage.

Background
It would be difficult to trace back a single event as the genesis of computer supported collaborative
(CSCW) work, another name for groupware. But likely it would be the introduction of Internet in the Defense Advanced Research Projects Agency's network, ARPANET in the early 1960s. Growth of CSCW beyond this network was largely stagnant during the 1970s. But in the early to mid 1980s the growth of local and wide area networks enabled the growth of group sharing & communication.
In the mid eighties Byte Magazine created an on-line forum about computing called BIX, accessed through dial up modems. BIX spawned the later similar efforts including CompuServe and America
Online. Then during the late 80s three significant commercial groupware products appeared. They were Co-ordinator, GroupSystems, and Lotus Notes. Co-ordinator was the first product to formalize decision processes for groups using the computer. GroupSystems extended this idea considerably to include all phases of the decision cycle to include information gathering, filtering and prioritizing.
Lotus Notes stormed the groupware arena by being the first to add capability to share, segment, and protect all forms of digital data on a massive scale. In the mid 1990's the onset of the windows browser and the base communications technology of the world wide web opened up collaboration on a worldwide basis. During the same period, desktop level videoteleconferencing was catapulted onto the Internet through the shareware release of CUSeeMe, a product developed at Cornell
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University. Now groupware products such as Lotus Notes, originally designed to operate on private networks, are being adapted to utilize the Internet infrastructure. Other Internet technologies such as "living worlds" are new outgrowths specifically oriented toward socialization and collaboration.
THE COMPUTER SUPPORTED COLLABORATIVE WORK TECHNOLOGIES
The following provide an overview of the groupware technologies electronic mail, videoteleconferencing, collaborative databases, workflow, group decision support systems, and living worlds.
Electronic Mail
During the early 1990's electronic mail (e-mail) moved from being unusual to being universal. In the last two years e-mail has moved outside the organization to a worldwide base using Internet servers as post offices. Virtually all e-mail systems now supply the user with the capability to sort incoming messages. The more sophisticated packages also provide the user with a capability to apply rules to incoming messages, and to be alerted when new messages arrive. Also on the increase are standards such as Standard Mail Transport Protocol (SMTP) and Multipurpose Internet
Mail Extensions (MIME). These standards ease the transfer of messages and extend the capability to allow users to attach different types of digital products (e.g. graphics or sound files) to the message. Once a mail user is tied to the Internet, he may then join LISTSERV groups. These groups are forums for discussing issues of similar interest through the e-mail system. A more recent trend has been to extend e-mail systems to include calendaring and scheduling, discussion groups and note taking. These capabilities are available in the more popular e-mail packages
Collaborative Database Systems / Intranets
When the term groupware is spoken, the image conjured by most professionals is that of the shared, collaborative database. The contents of the database could vary widely dependent upon the application. It may be scanned legal documents to be accessed by members of a legal team, categorized technical information for a team of consultants, customer data for the sales team, or operational data for a production line team. But what differentiates a collaborative database from a conventional database management system? Some of the characteristics unique to a collaborative database include: tight integration with e-mail, replication of data worldwide, control of access to data through distributed database managers, built-in discussion threads, group database templates, a common collective user interface, and also meta information about group activity.
The Intranet
An intranet is a privately owned information network that utilizes the protocols, tools, and languages of the internet. Primary protocols include TCP/IP, DNS, HTTP, FTP, CGI, SMTP,
Usenet, and IRC. The principal tools utilized in an Intranet environment are servers (with utilities), browsers, and web page organization tools. Languages include HTML, VRML, JAVA and
Javascript. The server is central to an Intranet because it must be able to store and deliver the data through the variety of protocols.
The current principal function of an intranet is to allow network users to view organizational information through their internet browser. In their current stages intranets are "hacked" networks, that is, they are hand coded and are largely disorganized. Many hackers are touting intranets as being cost effective ways to distribute a company's knowledge. Business managers should be
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aware, however, that intranet development is in a similar stage to where data processing systems were in the early 1960's. Without properly controlled growth at this stage, costs to maintain these networks in out years will be astronomical. Some vendors are beginning to come out with products to help organize and control this material. These include Lotus, Novell, and Netscape. The Lotus entry in this market, termed Domino, allows previous Notes applications to be migrated directly to the Internet protocols, yet maintain all the groupware functionality resident in Notes.
There are thousands of applications that have been built using collaborative database structures.
Typically however an organization will utilize an environment such as Lotus Notes to operate their entire information system infrastructure.
Workflow
Workflow technology is a provision for computer based aids to enhance the flow of the essential business information and process in an organization. Bringing workflow technology into an organization involves two major phases. The first phase is an examination of current data and information flows. The second phase is the programming of a "cooperating" database and e-mail system to streamline those flows. Packaged tools exist for both these phases. Some vendors specialize in this arena and offer complete solutions.
In the first phase, an analyst would document activity such as the current data collection and routing processes, volumes, what individuals act upon what data, decision points, what decisions are made, and how the decisions affect the flow. Often an examination such as this would reveal duplication of effort and work for which no justification can be found. All the personnel involved in the original work would be intimately involved in this group process and examination. Tools for performing this type of analysis are based upon discrete event or continuous simulation.
Based upon the first phase examination, a system would be cooperatively re-designed to reflect a streamlined flow. Then based upon the new design, a programmer would utilize a tool such as
Lotus Notes to build multiple forms with rules and ties to current data stores. The routing (via an email engine) would then automatically update, validate and verify the data as it is passed through appropriate channels.
A large advantage to workflow systems is the ability to gather meta-data about the operation of a system. Bottlenecks or other areas of challenge can be discovered and rectified through the application of greater resources or by changing the rules or flow structures in a system.
Videoteleconferencing
Videoteleconferencing (VTC) could be defined as the exchange of video signals between two or more points. An important quality of VTC is the ability to see and hear others over long distances.
Most VTC systems today also have associated "blackboard" sharing capability. These blackboards allow participants to view and modify common images, and share, through multiple screen cursors, common applications such as spreadsheets. There are a wide range of options for implementing
VTC. A particularly interesting new approach toward VTC is the use of video servers on the
Internet to allow groups of eight or ten individuals, where each individual is at a different physical location, to meet.
There are many issues in implementing VTC systems: Connectivity, Bandwidth, Transport
Medium, Cost, Image Quality, Availability, Reliability, and Setup.
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Group Decision Support Systems
The Nobel Laureate Herbert Simon separated "good" decision making into three separate stages intelligence, design, choice and Implementation - IDCI. But if we were to examine the group decision process that most organizations follow we would likely find that it could be defined as
BOGGSAT - a Bunch of Guys & Gals Sitting Around Talking. Think of the some common characteristics of decision meetings we have all attended;
- most of the meeting was spent pursuing irrelevant tangents,
- one or two people dominated the meeting,
- there were times when everyone was speaking at the same time,
- minutes were taken from a singular point of view, leaving out important comments or issues,
- people with bright ideas feared speaking up in a politically charged atmosphere,
- the actual decision was reached hurriedly in the last 5 minutes of the meeting,
- many of the right people didn't attend,
- more new issues were surfaced than those that were resolved,
- there was no way to organize the issues at hand, and
- in the end nobody really knew whether there was a final consensus on the decision or not.
These are frightening factors when you think about the potential consequences of decisions made by groups. Is there any way that we can reducing or eliminate these problems? Yes, there is. New methods and tools for controlling most of these challenges are available. They are called group decision support systems (GDSSs). GDSSs utilize a controlled atmosphere, a defined process, and a bag of tools for supporting groups making major decisions.
The Controlled Atmosphere
Common sense dictates that a meeting where participants seek to accomplish a reasonable set of objectives should be held in a controlled atmosphere. This is a neutral environment where the meeting may proceed without interruption, where critical data is readily available, and where participants can effectively see, hear and respond to the each other. For generations the traditional conference room has fulfilled this need. The introduction of information technology to add speed, corporate memory and networking capability to the organizational meeting has promulgated the growth of a new atmosphere termed "Decision Rooms." These are rooms where tables with embedded computer screens and keyboards are arranged in a U shape. In the same room, multiple projection devices allow interface with simultaneous information sources such as a video teleconference, a database of opinions, and web pages.
The Defined Process
One of the principal problems with traditional meetings is that frequently the meetings are entirely ad-hoc. There are no defined objectives, no specified times for moving among topics, no methods for assuring that all that needs to be said, is said, nor even a way to assure that the correct parties are participating. In a GDSS environment the meeting process is much more well defined. There is
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time for diverging, time for converging, time for deciding how to decide. In addition to the "right" participants, the defined process requires three key players: the process owner, a facilitator, and a technographer. The process owner is the person or persons who must go forth with the decisions made in the decision room session. They must have the power to enact the recommendations. The process owner collaborates with the facilitator to establish a timetable and an agenda well in advance of the actual meeting. The facilitator is responsible for keeping the meeting moving, staying on the agenda, assuring equal time for participants, and encouraging discussion. The facilitator must be a neutral, impartial party. The technographer is an individual trained in the technical workings of the software. It is their job to move the data around as unobtrusively as possible during the actual meeting. In this manner the participants can focus upon the session content. The Bag of Tools
GDSS's, also frequently referred to as Electronic Meeting Systems (EMSs) are characterized by tool sets that provide capability for the group to set an agenda, and then to do brainstorming, filtering, classifying, and prioritizing of the issues at hand. These tool sets overcome most of the challenges discussed in the first section above. They provide anonymity, complete record keeping, parallel data entry from all individuals, a smooth sequence for the meeting, forced focus upon the issues surfaced, fast issue organization, and multiple methods for establishing priorities. A rather fascinating phenomenon happens in these environments - the focus of the discussion moves away from attaching the worth of an idea to its originator, to judging the idea based upon its own merit.
Living Worlds
Living Worlds (LW) is a moniker for a technology that combines virtual reality environments with live voice and avatars on the Internet. Avatars are physical likenesses (or un-likeness as you prefer) of ourselves that can move among and be seen within all the thousands of virtual reality worlds out on the Internet. A specific Internet site called Onlive now has living worlds where you can go visit and talk with others in a virtual reality sports bar or gambling casino. Living Worlds describe a new extension to current standards for Virtual Reality on the Internet.
THE FUTURE
Two trends are likely for groupware. The first is that the use of groupware will continue to grow, at an even faster pace, with the platform of choice being the Internet. The second is that the previous distinctions of time and place will disappear.
As more groupware solutions are installed and become better know, corporate managers will further recognize that data and knowledge are a group asset versus an individual one. To stay competitive an organization must capitalize upon all its knowledge assets, and retain this knowledge even when a person leaves. At the same time partnering between organizations is becoming an increasing necessity. Tools for aiding this process will be more important than ever.
In an early work on computer aided collaboration , Dr. Bob Johansen of the Institute for the Future divided the approaches and computer aiding tools in the groupware arena into four categories including 

same-time same-place,



same-time different-place,
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

different-time same-place, and



different-time, different-place.

Due to the spread of the Internet, and the variety of available groupware solutions, the importance of time and place will disappear. Organizations will be able to fit any of a number of solution approaches to their own needs. In cases where schedule conflicts exist, intelligent agents will attend meetings and make decisions about the importance of matters, reporting these back to owners.
Individuals will be able to attend meetings worldwide in three dimensional environments with full sensory feedback. And combined with other decision technology such as genetic algorithms and neural networks, systems will perform data mining in collaborative databases to provide the very best in the right information at the right time.


Software development staff may find incomplete and/or inconsistent requirements as the prototype is developed.



A working, albeit limited, system is available quickly to demonstrate the feasibility and usefulness of the application to management.



The prototype may be used as a basis for writing the specification for a product-quality system.

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