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

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whether you want to have a palette or a menu. If you don't know why, you don't know whether the same or a different choice makes sense for you. Bill Atkinson's MacPaint program was one of the standard- setting early Macintosh programs, and it used a tool palette, a box on the side of the window containing icons. The icons on the palette stand for various functions like "enter text", "move view window", "draw a rectangle", and the like. Why was this a good design choice, rather than just listing these functions in a pull-down menu? In fact, some similar functions are listed in a pulldown menu called "goodies". So should you have a palette for what you are doing or not? Here are some of the considerations: Operations on menus usually do not permit or require graphical specification of parameters, though they can require responding to queries presented in a dialog box. So an operation like "draw a rectangle", in which you would click on the corners of the intended rectangle, would be odd as a menu item. A palette selection actually enters a MODE, a special state in which things happen differently, and keeps you there. This doesn't happen when you make a menu selection. For example, if you select the tool for drawing rectangles from a palette, your mouse clicks get interpreted as corners of rectangle until you get out of rectangle drawing mode. If you selected "draw a rectangle" from a menu, assuming the designer hadn't been worried about the point above, you'd expect to be able to draw just one rectangle, and you'd have to go back to the menu to draw another one. So a tool palette is appropriate when it's common to want to do a lot of one kind of thing rather than switching back and forth between different things. Modes are generally considered bad. An example which influenced a lot of thinking was the arrangement of input and command modes in early text editors, some of which are still around. In one of these editors what you typed would be interpreted either as text to be included in your document, if you were in input mode, or as a command, if you were in command mode. There were two big problems. First, if you forgot what mode you were in you were in trouble. Something you intended as text, if typed in command mode, could cause the system to do something dreadful like erase your file. Second, even if you remembered what mode you were in, you had the bother of changing modes when you needed to switch between entering text and entering commands. But modes controlled by a tool palette are considered OK because: there is a change in the cursor to indicate what mode you are in, so it's harder to forget; you only get into a mode by choosing a tool, so you know you've done it; it's easy to get out of a mode by choosing another tool. In a tool palette, tools are designated by icons, that is little pictures, whereas in menus the choices are indicated by text. There are two sub-issues here. First, for some operations, 76
like drawing a rectangle, it's easy to come up with an easily interpretable and memorable icon, and for others it's not. So sometimes icons will be as good as or better than text, and sometimes not. Second, icons are squarish while text items are long and thin. This means icons PACK differently on the screen: you can have a bunch of icons close together for easy viewing and picking, while text items on a menu form a long column which can be hard to view and pick from. So... this tells you that you should use a tool palette in your application if you have operations that are often repeated consecutively, and you can think of good icons for them, and they require mouse interaction after the selection of the operation to specify fully what the operation does. Depending on the style guide you are using, you may or may not find a good, full discussion of matters like this. One of the places where experience will pay off the most for you, and where talking with more experienced designers will be most helpful, is working out this kind of rationale for the use of various interface features in different situations. 3.4.3 WHEN YOU NEED TO INVENT At some point in most projects you'll probably feel that you've done all the copying that you can, and that you've got design problems that really call for new solutions. Here are some things to do. Think again about copying. Have you really beaten the bushes enough for precedents? Make another try at locating a system that does the kind of thing you need. Ask more people for leads and ideas. Make sure the new feature is really important. Innovation is risky and expensive. It's just not worth it for a small refinement of your design. The new feature has to be central. Be careful and concrete in specifying the requirements for the innovation, that is, the context in which it must work. Rough out some alternatives. Analyze them, and be sure of what you are doing. 4.0 CONCLUSION In this unit, you have been introduced to the concept of understanding users. Task analysis and how it applies in user interface design was also discussed. Using task in design and creating initial design were also discussed. 5.0 SUMMARY What you have learnt in this unit concerns Understanding users which involves figuring out who is going to use the program and for what it is been used for. 77
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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
Page 26 and 27: 3.1.1 DESIGNING A GOOD USER INTERFA
Page 28 and 29: widgets properly is to read and und
Page 30 and 31: Figure 1:- Showing that alignment o
Page 32 and 33: 6.0 TUTOR MARKED ASSIGNMENT a. How
Page 34 and 35: A graphical user interface is a typ
Page 36 and 37: Operating System. It is easy for a
Page 38 and 39: A list of items from which to selec
Page 40 and 41: collaborative work. For example, sc
Page 42 and 43: MODULE 1 UNIT 4 HUMAN COMPUTER INTE
Page 44 and 45: 3.3 DIFFERNCES WITH RELATED FIELDS
Page 46 and 47: window blinds to automobile braking
Page 48 and 49: Wickens, Christopher D., John D. Le
Page 50 and 51: The International Ergonomics Associ
Page 52 and 53: approach, the Gilbreths reduced the
Page 54 and 55: 3.6 BENEFITS OF ERGONOMICS The thre
Page 56 and 57: Another key to reducing lumbar disc
Page 58 and 59: MODULE 2 - USER INTERFACE DESIGN TE
Page 60 and 61: methods include inspection methods,
Page 62 and 63: Determine time of each operation (b
Page 64 and 65: unable to understand new informatio
Page 66 and 67: M cones, or, misleadingly, green co
Page 68 and 69: Motor skill which is a learned seri
Page 70 and 71: MODULE 2 UNIT 2 UNDERSTANDING USERS
Page 72 and 73: The users of a system must be ident
Page 74 and 75: This example brings up an important
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Page 80 and 81: MODULE 2 UNIT 3 USER CENTERED DESIG
Page 82 and 83: or small body text is also hard to
Page 84 and 85: Introduction to User-centered desig
Page 86 and 87: organizations themselves. Interacti
Page 88 and 89: After thorough analysis using vario
Page 90 and 91: Interaction design which is the dis
Page 92 and 93: In human-computer interaction and c
Page 94 and 95: The preferred method for ensuring u
Page 96 and 97: 3.4 ISO STANDARDS FOR USABILITY ISO
Page 98 and 99: In this unit, you have been introdu
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Page 104 and 105: The term direct manipulation was in
Page 106 and 107: 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
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Page 124 and 125: DENIM, an extension of SILK, is a t
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• Encourage menu & forms style, r
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Another problem is that native widg
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interfaces, so that a realistic sim
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UNIT 3 INPUT AND OUTPUT MODELS Tabl
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Recall that perceptual fusion means
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3.2 OUTPUT MODEL There are basicall
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directly-mapped pixel image will no
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Most stroke models also include som
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UNIT 4 MODEL VIEW-CONTROLLER (MVC)
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3.3.2 AS A DESIGN PATTERN MVC enco
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The Views are XForms controls for s
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UNIT 5 LAYOUTS AND CONSTRAINTS Tabl
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3.5 CONSTRAINTS Constraints are rel
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MODULE 4 UNIT 1 TECHNIQUES FOR EVAL
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a. Card Sorting Card sorting is a w
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Rapid prototyping is a method used
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3.2.1 THE USE OF PROTOTYPES It is o
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Dumas, J.S. and Redish, J.C. (1999)
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the users' respect for you as a pro
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the users will be and what kind of
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speed whenever the average load was
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Table 4:- Table: Average times for
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phases: list the actions, and then
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Nielsen and Molich used their own e
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7.0 REFERENCES AND FURTHER READING
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users. If you do not, you can be ba
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If you are led to develop more and
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It's very easy to shape the comment
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a. Analyzing the Bottom-Line Number
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you use. But then you need some way
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ecruit test users with more similar
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MODULE 4 UNIT 4 OTHER EVALUATION IS
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3.2 CURRENT ISSUES CONCERNING EVALU
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2.0 OBJECTIVES By the end this unit
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It provides a real focal point for
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3.3.4 CONDUCTING THE TEST Having co
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The stages involved in usability te
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