User Interface Design and Ergonomics - National Open University of ...

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3.2.1 THE USE OF PROTOTYPES It is often very difficult for designers to conduct usability tests with the exact system being designed. Cost constraints, size, and design constraints usually lead the designer to creating a prototype of the system. Instead of creating the complete final system, the designer may test different sections of the system, thus making several small models of each component of the system. The types of usability prototypes may vary from using paper models, index cards, hand drawn models, or storyboards. Prototypes are able to be modified quickly, often are faster and easier to create with less time invested by designers and are more apt to change design; although sometimes are not an adequate representation of the whole system, are often not durable and testing results may not be parallel to those of the actual system. 3.2.2 METRICS While conducting usability tests, designers must use usability metrics to identify what it is they are going to measure, or the usability metrics. These metrics are often variable, and change in conjunction with the scope and goals of the project. The number of subjects being tested can also affect usability metrics, as it is often easier to focus on specific demographics. Qualitative design phases, such as general usability (can the task be accomplished?), and user satisfaction are also typically done with smaller groups of subjects. Using inexpensive prototypes on small user groups provides more detailed information, because of the more interactive atmosphere, and the designer's ability to focus more on the individual user. As the designs become more complex, the testing must become more formalized. Testing equipment will become more sophisticated and testing metrics become more quantitative. With a more refined prototype, designers often test effectiveness, efficiency, and subjective satisfaction, by asking the user to complete various tasks. These categories are measured by the percent that complete the task, how long it takes to complete the tasks, ratios of success to failure to complete the task, time spent on errors, the number of errors, rating scale of satisfactions, number of times user seems frustrated, etc. Additional observations of the users give designers insight on navigation difficulties, controls, conceptual models, etc. The ultimate goal of analyzing these metrics is to find/create a prototype design that users like and use to successfully perform given tasks. After conducting usability tests, it is important for a designer to record what was observed, in addition to why such behavior occurred and modify the model according to the results. Often it is quite difficult to distinguish the source of the design errors, and what the user did wrong. However, effective usability tests will not generate a solution to the problems, but provide modified design guidelines for continued testing. 160
4.0 CONCLUSION The concept of evaluation of user interface without the users was introduced in this unit. Users walkthrough, action analysis and heuristics analysis concepts was also discussed in greater detail while emphasis on the need for evaluation was also introduced. . 5.0 SUMMARY Cognitive modeling involves creating a computational model to estimate how long it takes people to perform a given task. Inspection usability evaluation methods involve observation of users by an experimenter, or the testing and evaluation of a program by an expert reviewer. They provide more quantitative data as tasks can be timed and recorded. Inquiry usability evaluation methods involve collecting qualitative data from users. Although the data collected is subjective, it provides valuable information on what the user wants. Rapid prototyping is a method used in early stages of development to validate and refine the usability of a system. It can be used to quickly and cheaply evaluate user-interface designs without the need for an expensive working model. Testing usability evaluation methods involve testing of subjects for the most quantitative data. Usually recorded on video, they provide task completion time and allow for observation of attitude. Cognitive walkthrough is a method of evaluating the user interaction of a working prototype or final product. It is used to evaluate the system’s ease of learning. Usability metrics is used to identify the features that will be measured. 6.0 TUTOR MARKED ASSIGNMENT a. Explain Cognitive modeling. b. Describe GOMS briefly. c. Identify some metrics and use them to evaluate the main menu interface of WINDOWS OS 7.0 REFERENCES AND FURTHER READING www.wikipedia.org Holm, Ivar (2006). Ideas and Beliefs in Architecture and Industrial design: How attitudes, orientations, and underlying assumptions shape the built environment. Oslo School of Architecture and Design. ISBN 8254701741. Wickens, C.D et al. (2004). An Introduction to Human Factors Engineering (2nd Ed), Pearson Education, Inc., Upper Saddle River, NJ : Prentice Hall. 161
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] NATIONAL OPEN UNIVERSITY OF NIGER
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National Open University of Nigeria
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Summary ...........................
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UNIT 3 - GRAPHICAL USER INTERFACE (
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Assignments File Tutor-Marked Assig
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2 DESIGN and DESIGNING GOOD USER IN
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need both the study unit you are wo
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CIT 711: USER INTERFACE DESIGN AND
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UNIT 1 FUNDAMENTALS OF USER INTERFA
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3.3 TYPES OF USER INTERFACES Curren
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3.5 USER INTERFACE MODALITIES AND M
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Table of Contents 1.0 Introduction
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3.1.1 DESIGNING A GOOD USER INTERFA
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widgets properly is to read and und
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Figure 1:- Showing that alignment o
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6.0 TUTOR MARKED ASSIGNMENT a. How
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A graphical user interface is a typ
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Operating System. It is easy for a
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A list of items from which to selec
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collaborative work. For example, sc
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MODULE 1 UNIT 4 HUMAN COMPUTER INTE
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3.3 DIFFERNCES WITH RELATED FIELDS
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window blinds to automobile braking
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Wickens, Christopher D., John D. Le
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The International Ergonomics Associ
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approach, the Gilbreths reduced the
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3.6 BENEFITS OF ERGONOMICS The thre
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Another key to reducing lumbar disc
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MODULE 2 - USER INTERFACE DESIGN TE
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methods include inspection methods,
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Determine time of each operation (b
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unable to understand new informatio
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M cones, or, misleadingly, green co
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Motor skill which is a learned seri
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MODULE 2 UNIT 2 UNDERSTANDING USERS
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The users of a system must be ident
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This example brings up an important
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whether you want to have a palette
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Task analysis which includes identi
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MODULE 2 UNIT 3 USER CENTERED DESIG
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or small body text is also hard to
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Introduction to User-centered desig
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organizations themselves. Interacti
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After thorough analysis using vario
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Interaction design which is the dis
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In human-computer interaction and c
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The preferred method for ensuring u
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3.4 ISO STANDARDS FOR USABILITY ISO
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In this unit, you have been introdu
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affect the way the command is execu
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• Guides the user via the predefi
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The term direct manipulation was in
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There are two important reasons for
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Page 110 and 111: UNIT 1 PROTOTYPING Table of Content
Page 112 and 113: Figure 12: The iterative steps of p
Page 114 and 115: select print Figure 13: An interfac
Page 116 and 117: Ambler, S.W. & Constantine, L.L. (2
Page 118 and 119: 3.2 LOW-FIDELITY PROTOTYPES Low-fid
Page 120 and 121: Figure 14:- Example of Sketching II
Page 122 and 123: Much more important for features th
Page 124 and 125: DENIM, an extension of SILK, is a t
Page 126 and 127: • Encourage menu & forms style, r
Page 128 and 129: Another problem is that native widg
Page 130 and 131: interfaces, so that a realistic sim
Page 132 and 133: UNIT 3 INPUT AND OUTPUT MODELS Tabl
Page 134 and 135: Recall that perceptual fusion means
Page 136 and 137: 3.2 OUTPUT MODEL There are basicall
Page 138 and 139: directly-mapped pixel image will no
Page 140 and 141: Most stroke models also include som
Page 142 and 143: UNIT 4 MODEL VIEW-CONTROLLER (MVC)
Page 144 and 145: 3.3.2 AS A DESIGN PATTERN MVC enco
Page 146 and 147: The Views are XForms controls for s
Page 148 and 149: UNIT 5 LAYOUTS AND CONSTRAINTS Tabl
Page 150 and 151: 3.5 CONSTRAINTS Constraints are rel
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Page 154 and 155: MODULE 4 UNIT 1 TECHNIQUES FOR EVAL
Page 156 and 157: a. Card Sorting Card sorting is a w
Page 158 and 159: Rapid prototyping is a method used
Page 162 and 163: Dumas, J.S. and Redish, J.C. (1999)
Page 164 and 165: the users' respect for you as a pro
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Page 168 and 169: speed whenever the average load was
Page 170 and 171: Table 4:- Table: Average times for
Page 172 and 173: phases: list the actions, and then
Page 174 and 175: Nielsen and Molich used their own e
Page 176 and 177: 7.0 REFERENCES AND FURTHER READING
Page 178 and 179: users. If you do not, you can be ba
Page 180 and 181: If you are led to develop more and
Page 182 and 183: It's very easy to shape the comment
Page 184 and 185: a. Analyzing the Bottom-Line Number
Page 186 and 187: you use. But then you need some way
Page 188 and 189: ecruit test users with more similar
Page 190 and 191: MODULE 4 UNIT 4 OTHER EVALUATION IS
Page 192 and 193: 3.2 CURRENT ISSUES CONCERNING EVALU
Page 194 and 195: 2.0 OBJECTIVES By the end this unit
Page 196 and 197: It provides a real focal point for
Page 198 and 199: 3.3.4 CONDUCTING THE TEST Having co
Page 200: The stages involved in usability te
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