For example navigation constructs should not change

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Unformatted text preview: stency is the most important design principles for usable systems. This can be applied at multiple levels; at first a system should at the bare minimum be consistent within itself. For example, navigation constructs should not change across different parts of the system. If the selection of a check box button in one part of the system indicates that a feature is active, this should be the standard thought-out the system. Therefore, users should not have to wonder whether different words, situations, or actions mean the same thing. Better to follow platform conventions. Nielsen (1990) 5. Error Prevention According to Nielsen (1990) good error messages that make sense to the user are always necessary. It is ideal to create a “careful design” which prevents a problem from occurring in the first place. Error-prone conditions should be eliminated or check for them and present users with a confirmation option before they commit to an action. 6. Recognition versus Recall Nielsen (1990) recommends that the user's memory load should be minimized by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another part. Instructions for use of the system should be clearly visible or else easily retrievable whenever needed. We see this principle in use every day, in street signs, the letters painted on keyboard key caps, iconic instructions for using a gasoline pump to fill our cars etc. The secret is to strike a balance between knowledge that is stored in the head and information that is externalized. Too much reliance on memorized information makes a system difficult to learn and use. 7. Flexibility of use According to Nielsen (1990) system should be flexible to use for every one. Since, user’s levels of experience with systems can very; this leads to the necessity of having 39 multiple “views” of users. Mainly, users can be divided into four types based on their experience and comfort level with a given system: i). Novice users: has little to no experience using system. Must often consult user manual, online help etc. Enjoys a minimal use of system functionality. ii). Intermediate users: are familiar with many aspects of system. Consults the manual infrequently and able to perform most tasks with ease. iii). Power user: know the system very well from an end-user perspective. Actively seeks way to optimize performance by using hidden “accelerator” aspect. Almost never consults manual. iv). Expert user: not only knows how to use system, but also understands its internal working. Therefore, system should be flexible to cater both inexperienced and experienced users. 8. Aesthetic and minimalist design According to Nielsen (1990) dialogues should not contain information which is irrelevant or not often needed. Each extra unit of information in a dialogue competes with the relevant units of information and reduce its relative visibility. 9. Sensible error messages According to Nielsen (1990) error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution. Ideally, error message should explain what happened in terms of understanding to the user. One of the most important heuristics in usability is to use the user’s natural language. This is particularly true with regard to error messages, since user is the most in need of good usability when a system is not performing as expected. The designers should avoid using any system or technical language which is not easily understandable by common users. 10. Help and documentation According to Nielsen (1990) it is an ideal situation that a system can be used without documentation, however sometime it may be necessary to provide help and documentation for particular system. This is rarely the case with wireless applications, since most wireless application binaries are too small to become overly complex. Any such information (documentation) should be easy to search, focused on the user's task, list concrete steps to be carried out and should not be too big. 40 CHAPTER 3. CONCEPTUAL FRAMEWORK According to Miles and Huberman (1994, p.18) “The conceptual framework explains, either graphically or in narrative form, the main things to be studied.” In our previous chapters presented we have described background and problem discussion about our research purpose. In this chapter we will take concepts from literature review to build our conceptual framework: RQ 1. Does the design of current WAP services contain major usability flaws? In the previous section, we have studied usability engineering, usability principles, usability attributes and usability principles for WAP services. We found that earlier research conducted by Ramsay 2001, Condos et al, 2002 and Nielsen 1993 is very much useful to answer our first research question to workout does the design of current WAP services contain major usability flaws? Usability Principles for WAP Services defined by Condos et al., (2002) Avoid unnecessary use of graphics Avoid long lists and indicate the length of the list Make important options visible to the user Provide clear, helpful and meaningful error messages Avoid dead ends Format and present content appropriately Offer consistency in navigation and naming of menu options Provide the user with sufficient prompting Minimize user input Structure tasks to aid the user...
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