ASSESSMENT FOR HCI

1. Human Computer Interaction (HCI) is about designing computer systems that support people so that they can carry out their activities productively and safely. HCI has a role in the design and development of all kinds of systems, ranging from those like air traffic control and nuclear processing, where safety is extremely important to office systems, where productivity and job satisfaction are paramount, to computer games, which must excite and engage users.

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HCI studies the communication between man and machine. In the past few years it advanced to the fastest growing sectors of the computer industry as the complex systems are at the brink of becoming unmanageable and use able by normal people. HCI involves both hardware and software user and system modelling, cognitive and behavioural sciences, human factors, empirical studies, methodology, techniques and tools.

2. All HCI takes place within a social and organisation context. Different kinds of applications are required for different purposes and care is needed to divide tasks between humans and machines, making sure that those activities that are creative and non-routine are given to people and those that are repetitive and routine are allocated to machines. Knowledge of human psychological and physiological abilities and more important still, their limitations is important. As this figure shows below this involves knowing about such things as human information processing, language, communication interaction and ergonomics. Similarly it is essential to know about the range of possibilities offered by computer hardware and software so that knowledge about humans can be mapped on to the technology appropriately. The main issues for consideration on the technology side involve input and output techniques, dialogue techniques, dialogue genre or style computer graphics and dialogue architecture. Tools and techniques are needed to realise systems. Evaluation also plays an important role in this process by enabling designers to check that their ideas really are what users want.

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3. The impacts of the following are :-
VDUs :- One issue in particular, which has been the focus of considerable media attention is health hazards and the use of VDUs. All sorts of claims have been made about the potentially dangerous physical effects of prolonged use of VDUs. The most scare mongering have included the inducement of epileptic fits, spontaneous abortions and radiation sickness, and the development of contacts and skin diseases. Those more commonly reported include complaints of eye strain, headaches and muscular fatigue. Clearly this is very sensitive issue where the application of HCI knowledge and research can clarify the nature of the problems. The situation however is by no means clear-cut and there is considerable conflicting evidence. With regard to radiation induced effects, it appears that these should be minimal since the emission level of radiation from VDUs is no higher than natural background levels (Terrana et al., 1980). But there may still be cause for concern in particular circumstances, such as long term exposure and low level emissions from other equipment components. In contrast there is considerable evidence to suggest that using VDUs can cause a number of visual, skeletal and muscular strains, the most common symptoms of which are burning, of which are burning, itching and watering eyes, blurred vision, aching shoulders and backache. Keyboard inputs:- The most common method of entering information into the computer is through a keyboard. Since you have probably used them a lot without perhaps thinking about the related design issues, thinking about keyboards is a convenient starting point for considering input design issues. Broadly defined , a keyboard is a group of on-off push buttons which are used either in combination or separately. Such a device is a discrete entry device. These devices involve sensing, essentially one of two or more discrete positions( for example keys on keyboards, touch-sensitive switches and buttons) which are either on or off, where as others (for example, pens with digitising, tablets moving joysticks, roller balls and sliders) involve sensing in a continuous range. Devices in this second category are therefore, known as Continuous entry devices.
Pointing devices :- Pointing devices are input devices that can be used to specify a point or path in a one, two or three dimensional space and like keyboards, their characteristics have to be considered in relation to design needs. Example pointing devices include joysticks, track balls and mice. Pointing devices are typically continuous entry devices, although a device like a mouse uses both continuous movement and (with its button) discrete movement.
Graphical interfaces :- Ideally, it may seem desirable to present information on the screen that has characteristics. The visual system could then use the same processes that it uses when perceiving objects in the environment. In particular, design and manufacturing applications might benefit from the use of realistic images in helping the users design and create objects. The problem with this approach however, is the high cost of real-time image generation. More over, when considered against the actual needs of an application, such a degree of realism is often unnecessary. For example, in a flight simulator it is less important to deceive pilots into believing that they are flying through real terrain than it is to provide all the necessary information in the right form to allow them to function as if they were in a plane. It is classified in terms of
(i) the various kinds of graphical modelling techniques used to represent three dimensional objects and scenes, and
(ii) the various forms of graphical coding used to represent different types of system information at the interface. The focus is on the efficacy of the different representational forms in terms of the function they are intended to provide, their perceptual discriminability and ease of recognition.

And more follows,

Graphical user interfaces (GUIs) have brought quantifiable benefits to users and organisations. Recent studies have shown that users of graphical user interfaces make fewer mistakes, feel less frustrated, suffer less fatigue, and are more able to learn for themselves about the operation of new packages than users of non- graphical or character-based user interfaces. From a software designer's point of view, however, GUIs are more difficult to design than character-based interfaces. The user's interaction with the GUI is more complex because it is based on principles of direct manipulation and concurrent user access to multiple windows, icons, menus and input devices. A character-based interface, however, normally only allows the user sequential access: first view a menu, then make a selection, then view the next screen, then enter the data. With the character-based interfaces the designer can (within limits) design the user interface so that the user will undertake a task in a predefined sequence. With the GUI, the designer can design the user interface so that certain actions are allowed on interface objects and the user will decide which actions to take and (within limits) in what order.

Systems which support groups of users working together are capable of bringing productivity gains to organisations; for example, by enabling design teams to collaborate on the development of computer-based designs and to hold discussions or brainstorming sessions over the network. Consulting companies can pool their world-wide expertise to prepare bids rapidly for complex projects. Normally group ware systems support users sharing information about common objects, such as a report, a bid or a design, in such a way that each user sees the same version of the object on their screen at the same time. The user interfaces to group ware systems are normally graphical but with the added complexity of supporting communication between group members and the sharing of common objects. Often many different media will be used to aid communication between group members; video and voice interaction may be as important as text and graphics. From a software designer's point of view, designing user interfaces for group ware systems is more difficult than designing a GUI because the designer must also consider multi-media interaction and support for communication between people.

The design and implementation of a successful user interface is important, therefore, not only to the software designer but also to users, groups and organisations. The next section describes the main activities which contribute to the design of the user interface and discusses the role of the software designer in each of these activities.

4. In the user interface design phase the design of the interface is determined and tested. This involves:-

*   the design of user actions

*   how to give feedback to the user

*   the screen design

*   design of possible user activities

*   representation of the system’s functionality to the user

*   planning of task sequences

*   design of access mechanisms

*   the design of user interface objects and interaction styles.

Classes of user interface

Interaction between the end-user and the system is achieved through interactive dialogues. There are a number of different classes of interactive dialogue and each of these has advantages and disadvantages depending on the situation in which they are used. The five major classes are discussed below:

a.Command language
Command language dialogues are those in which the user types instructions to the computer in a formally-defined command language. For example, `mv file1 file2', is a UNIX command for copying file1 into file2. The advantages of this approach is that it is very flexible, allowing users to create their own commands; it supports user initiative and it appeals to `power' users, typically to software and system developers. Command language usually requires a significant level of training and a high degree of memorisation.

b.Natural language
Natural language interfaces are those in which the user's command language is a significant, well-defined subset of some natural language such as English. For example `Which women work in New York City' is a typical user input to the Intellect system from AI Corp., Cambridge, MA. Natural language interfaces are typically easy to learn, although they often require considerable typing skills on the part of the user. They can also be slow to use if the system is unclear as to the exact meaning of the user request and has to seek clarification. However, natural language systems are increasing in sophistication and a great deal of research and development work is currently being undertaken.

c.Menu systems
Menu systems allow the user to issue commands by selecting choices from a menu of displayed alternatives. Menu systems are popular since they reduce learning time, reduce the number of keystrokes necessary and structure decision making. Most of the currently available fourth generation environments provide screen design tools which support the development of menu-based interfaces.

d.Form filling dialogues
Form filling dialogues are those in which the user enters data by filling in fields in one or more forms displayed on the screen. The use of forms on the screen considerably simplifies data entry and requires very little training to use. Forms management tools, similar to those available for menus, can be found within fourth generation environments.

e.Direct manipulation interfaces
Direct manipulation interfaces are those in which the user manipulates, through button pushes and movements of a pointing device such as a mouse, a graphic or iconic representation of the underlying data. An icon is a graphical symbol or pictogram used instead of words. Most direct manipulation interfaces use window systems or environments, in which the user's screen is divided into a number of possibly overlapping rectangular areas, each of which handles a specific function. Direct manipulation interfaces represent task concepts visually, are easy to learn and use, encourage exploration or experimentation with the system features and generally result in a high level of user satisfaction. Such interfaces are traditionally difficult to design and to program. However, most of the user interface design standards currently being put forward are based on direct manipulation interfaces. Choosing the most appropriate class of user interface to match the needs and expectations of the users is an important aspect of good user interface design. For any given class of user interface a number of design decisions must be made by the interface designer, particularly in terms of what information should appear on the screen, how much information, in what order, what type of error messages, where should error messages be displayed on the screen and so on.

5. There are several recognised styles of interaction that can be utilised.

Rapid or Throwaway prototyping :- is also used to collect information on requirements and on the adequacy of possible designs. In rapid prototyping, the prototype is thrown-away, in the sense that it is not developed into the final product, although it is an important resource during the project’s development. Recognises that requirements are likely to be inaccurate when first specified. The emphasis is an evaluating the prototype before discarding it in favour of some other implementation. Incremental prototyping :- allows large systems to be installed in phases to avoid delays between specification and delivery. The customer and supplier agree on core features and the implementation is phased to enable an installation of a skeleton system to occur as soon as possible. This allows requirements to be checked in the field so that changes to core features are possible extra, less important, features are then added later. The system is built incrementally, one section at a time. Incrementally prototyping is based on one overall design.
Evolutionary prototyping :- is the most extensive form of prototyping, it is a compromise between production and prototyping. The initial prototype is constructed, evaluated and evolved continually until it forms the final system. Some designers believe that more acceptable systems would result if evolutionary prototyping were interspersed with periods of requirements animation or rapid prototyping. The only problem is that evolutionary prototyping tends to encourage designers to “fix” on a particular solution too soon rather than exploring the alternatives more fully. Compromise between production and prototyping. The system can cope with change during and after development. Helps overcome the traditional gap between specification and implementation.
A full prototype as the name suggests, contains complete functionality although with lower performance.
A horizontal prototype shows the user interface but has no functionality behind the buttons.
A vertical prototyping contains all of the high level and low level functionality for a restricted part of a system.
High fidelity prototyping refers to prototyping through a medium, such as video, which resembles as closely as possible the final interface. High fidelity video prototypes tend to be popular with commercial organisations because they make the product appear very polished and aesthetically pleasing.
Low fidelity prototyping involves the use of materials that are further away from the final version and that tend to be cheaper and faster to develop. For example, a software version of the interface with cut down functionality would be higher fidelity than story boards.
Chauffeured prototyping involves the user watching while another person, usually a member of the development team, ‘drives’ the system. It is away to test whether the interface meets the user’s needs without the user actually having to carry out low level actions with the system. This may appear to contradict the intentions behind involving the user, but it can be useful for confirming, for example, the sequence of actions needed to perform a task.
Wizard of Oz prototyping also involves a third party, but in this case, the user is unaware of it. The user interacts with a screen, but instead of a piece of software responding to user’s requests, a developer is sitting at another screen answering the queries and responding to the real user. This kind of prototyping is likely to be conducted early in development to gain an understanding of the user’s expectations. There is an added advantage for the development team is using Chauffeured or Wizard of Oz prototyping in that extra understanding can be achieved through being involved so closely with the users.
             The use of different kinds of prototype in different stages of a design results in a two-phase view of iterative design. In the first phase, prototypes are developed to gather different forms of information, and radically different alternatives may be tested in parallel. At some point, this prototyping ends with a proposal for a single full initial design. One solution is then iterated through design, code and tested cycles. Any further radical changes are unlikely, as production standards will now be in force, and major changes will be expensive. This phase can be regarded as a convergent fine-tuning stage with a slow cycle time. The earlier prototyping phase, by contrast, is a divergent, exploratory and bold stage, with fast cycle times and the preservation of alternative designs.

6.
(a) The expert evaluation will be as follows, because the expert will evaluate it by looking at :-

*   the kind of information required,

*   the nature of the system or specification that is being evaluated,

*   the stage in the life cycle being evaluated

*   whether or not statistical validity is needed (for example, if you are doing a formal experiment or      large-scale survey)

*   the resources available.

Another answer:-

*   the characteristics of the users (or the predicted users) of the product who take part in the     evaluation (for example, experience, age, gender, psychological and physical characteristics)

*   the types of activities or predicted activities that the users will do. These may range from tightly      specified tasks, which are defined and controlled by an evaluator, to activities decided by the      users.

*    the environment of the study which may range from a controlled laboratory situation to a natural       work setting. If it is the latter, the study is known as a field study.

*    the nature of artefact being evaluated, which may be anything from a series of sketches to a       working software prototype or fully developed product.

Even in predictive evaluations, in which experts attempt to predict the usability of a system without directly involving users, evaluators take these same four aspects into account. They do this by drawing on their knowledge of the kinds of things that typical users would do and the sorts of circumstances in which they know typical users of the system will work.

User’s evaluation :- As well as examining user’s performance, it is important to find out what they think about using the technology. However good user’s performance scores are when using technology, if they do not actually like using it for some reason it will not be used. Sometimes, for example a quite small and seemingly trivial feature (to designers) may be extremely annoying to users. Surveys using questionnaires and interviews provide ways of collecting users’ attitudes to the system.
(b). Heuristic evaluation:- Molich and Nielsen (1990) devised a method known as heuristic evaluation in response to need for cheap, cost effective methods that could be used by small companies who could not afford or did not have the facilities, time or expertise necessary to do usability engineering. In heuristic evaluation reviewers examine the system or prototype as in a general review or usage simulation, but their inspection is guided by a set of high-level heuristics (Nielsen, 1992), which guide them to focus on key usability issues of concern. The following list is typical of the kind of heuristics that can be used.

*   use simple and natural dialogue

*   speak the users’ language

*   minimise user memory load

*   be consistent

*   provide feedback

*   provide clearly marked exits provide shortcuts

*   provide good error messages

*   prevent errors

According to Nielsen (1993) each reviewer normally does two or more passes through the interface in order to :

*   inspect the flow of the in the interface from screen to screen,

*   inspect each screen one at a time against the heuristics, examining features such as system      messages, dialogue and so on.

Cognitive Walkthroughs :- the third kind of expert review is a walkthrough. As in software engineering, the goal of a walkthrough in HCI design is to detect problems very early on so that they may be removed. Walkthroughs involve constructing carefully defined tasks from a system specification or screen mock- ups. A typical example would be to walk through the activities (cognitive and operational) that are required to get from one screen to another. Before doing the walk through experts determine the exact task that will be done, the context in which it will be done and their assumptions about the user population. They then walk through the task, reviewing the actions that are necessary to achieve the task, and attempt to predict how the user population would most likely behave and the problems that they would encounter. In many respects this is similar to a review, except that it requires a more detailed prediction of user behaviour.
            HCI researchers tend to adapt methods to fit their needs: Polson et al. (1992), for example, take a strongly cognitive stance. They describe their brand of cognitive walkthrough as a ‘hand simulation of the cognitive activities of user’. The focus is cognitive and the underlying aim is to identify potential usability problems. This is a fairly fine-grained approach, which relates closely to cognitive task analysis. By structuring the review process around specific questions, psychological theory can be embedded into it, which helps to illuminate how well the interface fulfils the cognitive needs of the intended users. The method is still being developed and more effective versions that can be adopted by companies may emerge.
Following is example of a checklist for doing a cognitive walkthrough.

Cognitive walkthrough start-up sheet Interface _____________________________________________________ Task _________________________________________________________ Evaluator(s) _______________________________ Date _______________

Task description: Describe the task from the point of view of the first-time user. Include any special assumptions about the state of the system assumed when the user begins work. Action sequence: Make a numbered list of the atomic actions that the user should perform to accomplish the task.
Anticipated users: Briefly describe the class of users who will use this system. Note what experience they are expected to have with systems similar to this one, or with earlier versions of this system.
User’s initial goals: list the goals the user is likely to form when starting a task. If there are other likely goal structures list them, and estimate for each what percentage of users are likely to have them.
Next action #:_______ Description:_______________________________________
1. Correct goals

II. Problems forming correct goals
A. Failure to add goals. ____%
B. Failure to drop goals. ____%
C. Addition of spurious goals. ____%
     No-progress impasse. ____%
D. Premature loss of goals. ____%
Supergoal kill-off. ____%

III. Problems identifying the action
A. Correct action doesn’t match goal. ____%
B. Incorrect actions match goals. ____%

IV. Problems performing the action
A. Physical difficulties. ___%
B. Time-outs. ___%

Evaluating guidelines :- Guidelines inevitably contain some overlapping and contradictory advice. Consistency might, for example, be important for learning to use a particular system but troublesome when a user becomes experienced. Many of these contradictions appear early and then disappear during the design process as high level principles become refined into lower level design rules. Often the constraints imposed by the characteristics of the users, their work and the environment will remove the need to choose between contradictory items of advice, because one refinement of a higher level principle will clearly apply when others do not. The skill that must be acquired in order to accumulate and apply guidelines wisely is the ability to evaluate them critically. So how does one evaluate guidelines?
               There is no mechanical technique. Principles have different forms, which affect how one goes about evaluating them. Generalisations such as ‘users will treat computer systems as if the latter were human’ are based on inductive reasoning from experience. We can see people doing this. Prescriptions such as ‘develop a consistent intuitive conceptual model when designing a system’ are based on deduction from the effects of not doing this. To evaluate guidelines based on inductive reasoning the data on which the principles are based be available. If, however, these data consist of the undocumented collective experiences of design community, then inexperienced designers cannot access them easily. For guidelines based on deduction, specialist knowledge may be the basis for many of the inferences that lead to the formulation of a principle. If the authors of a guideline do not present an argument for a guideline, it is easy to reject it, even if it is good. Authors may also present a false argument. A reasonable guideline such as keeping colour coding simple can appear unreasonable if tit is deduced from the wrong evidence and if it is made too specific (for example, allowing no more than seven colours at once).

Observing (laboratory and field) :- in one way or another, several different kinds of evaluation depend on some form of observation or monitoring of the way that users interact with a product or prototype. Observation or monitoring may take place informally in the field or in a laboratory as part of more formal usability testing. Alternatively, it may be done from a participative or ethnographic perspective with the aim of really trying to understand how users themselves interact with technology in natural settings. There are a number of techniques for collecting and analysing data. Data may be collected using direct observation with the observer making notes or some other form of recording such as video may be used. Keystroke logging and interaction logging can also be done and often they are synchronised with video recording. The way data is analysed will depend on the question that the evaluators want to answer.