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Usability in Mobile phone Design

Usability in Mobile phone Design. IMSE: 8810 Human Factor Instructor: Dr. Linsey Baker Student: Qiuyue Zhao. Outlines. 1. Introduction of usability What is usability? Usability in mobile phone design Why is usability important? How do we do usability? 2. Discussion of papers

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Usability in Mobile phone Design

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  1. Usability in Mobile phone Design IMSE:8810 Human Factor Instructor: Dr. Linsey BakerStudent: Qiuyue Zhao

  2. Outlines 1. Introduction of usability • What is usability? • Usability in mobile phone design • Why is usability important? • How do we do usability? 2. Discussion of papers • Paper 1: A framework for evaluating the usability of mobile phones • Paper 2: Systematic evaluation methodology for cell phone user interfaces • Paper 3: Chinese character entry for mobile phones 3. Final conclusion

  3. Usability: What is it? • Usability is also a method • “How can I improve ease-of-use during design” Usability can be a attribute… “How easy is this thing to use” we can therefore say… “that ipod has great usability” “that ipod was improved with usability”

  4. Usability: What is it? • Usability is a measure of quality • It’s defined by six quality components: • Effectiveness • Learnability • Efficiency • Memorability • Error Prevention • Satisfaction Jakob Nielsen Ben Shneiderman

  5. Main mobile problems Three features or limitations of mobile phone • Small screens • Awkward input, especially for typing • Processing power and available memory

  6. Usability in Mobile phone design Very heavy and awkward Smaller and more portable The first mobile phone with internal antenna Full QWERTY keyboard Multi-touch

  7. Why is usability important in Mobile phone design? Usability is often associated with the functionalities of the product • If it’s difficult to use, people won’t buy • If users get lost, they won’t buy • If it’s hard to read or doesn’t answer user’s key question, they won’t buy

  8. How do we do usability? • Early Focus on Users and Tasks • Know who the users are • Know what tasks the users will perform • Know Which are most important • Empirical Measurement (Evaluation methods) • Before starting the new design, test the old design. • Test your competitors' designs • Iterative Design • a cyclic process of prototyping, testing , analyzing, refining a product or process

  9. Usability Evaluation Methods(UEM) • Analytic methods • Claims analysis • Usability inspection • Heuristic evaluation • Cognitive walkthrough • Empirical methods • Think aloud • Questionnaires • User interview • User observation

  10. Paper 1 :A framework for evaluating the usability of mobile phone • What is this paper about? Propose a structuralizedusability evaluation model in order to help practitioners identify and organize critical usability problems in a systematic way,understand the relationships among usability factors,and generate better design ideas. • Why? • Pervious studies only focus on what could constitute the usability factors, seldom organize them in a systematically. • Most concerned with software products, not mobile phone. So do not reflect the feature of mobile phone appropriately.

  11. Something about Usabilityevaluation 1. Importance of usability evaluation 2. Usability design problems: • Interface features design (task-independent) • LUI: logistical user interface • GUI: Graphic user interface • PUI: Physical user interface • Users tasks design (task-dependent) 3. Usability Evaluation Methods(UEM)

  12. Section 1: Research method Step 1: collection and analysis of usability problems • First: classify usability problems into 2 categories • Task-independent problems (interface design features) • Task-dependent problems (user tasks) • Second: typically choose 28 mobile phone tasks • Third: associate usability problems with mobile phone tasks

  13. Section 1: Research method Step 2: Identification of design features to be evaluated • What interface features to evaluate Step 3: Evaluation strategy • How to evaluate interface feature • LUI evaluation • GUI evaluation • PUI evaluation • Task-based evaluation Choose from four kinds of evaluations

  14. Section 2:Proposed evaluation framework • Hierarchical model of usability factors Aim to evaluate Usability indicator Usability criteria Usability property

  15. Usability indicators • Visual support of task goals • Support of cognitive iteration • Support of efficient interaction • Functional support of user needs • Ergonomic support Cognitive interaction affective Physical aspect of interaction

  16. Partial list of Usability criteria

  17. Criteria checklist

  18. Section3:Usability evaluation framework Visual support of task goals

  19. Conclusion This study developed an evaluation framework for supporting usability practitioners to test the suability of mobile phones in an analytical way. • A hierarchical model of usability • Four sets of checklists • A quantification method • An evaluation process • Limitation • Mapping relationship between evaluation areas and usability indicators and its consequent evaluation items of the checklists. • The goal-mean relationship need to be further examined

  20. Paper 2: Systematic evaluation methodology for cell phone user interfaces • Object Develop a Systematic Evaluation Methodology for Cell Phone User interface(SEM-CPU). SEM-CPU is a specifically designed to integrate five empirical methods into a laboratory-based test in order to evaluate cell phone UIs.

  21. Three stages comprised to construct SEM-CPU Stage 1 Stage 2 Stage 3

  22. Stage1: Data collection in SEM-CPU • Five method • Scenario-based task performance Benchmark tasks: tasks that reflect the realistic context of use found outside of the laboratory • Voice Activated Dialing (VAD) • Short Messaging Service(SMS) • Phone Book(PB) • Questionnaires (six usability attributes: icons clarity, text label, ease of use, ease of locating functions, quality of feed back and overall satisfaction.) • Retrospective think-aloud instead of concurrent think aloud • User observation for critical incidents • Post-task interview

  23. Procedures of data collection

  24. Stage 2: Data analysis • Step 1: quantitative analysis • Effectiveness • Efficiency • Satisfaction • Learnability • Step 2: qualitative data transformation • Qualitative Data logging(QDL) template • step 3:navigation flow diagram analysis • Step 4:verbal protocol Task completion ratio(%) Task completion time(s) Error rates Ratings of satisfaction Task completion time and task completion ratio at repeated trails

  25. An example of the table with the reorganized results of verbal protocol/critical analysis

  26. Step 3: Navigation flow diagram analysis Advantage: can identify the cause of usability problems No apparent disability Cognitive disability Physical disability

  27. Stage 3: Data integration Triangulation strategy

  28. Example of design specification

  29. Conclusion This paper present a systematic methodology, called SEM-CPU, to evaluation cell phone UIs in laboratory-based testing. SEM-CPU guides usability engineers integrating five empirical methods to discover valid usability problems, and generate proper design specifications. • Efficiently conduct laboratory-based testing with multiple empirical methods • Collect and measure necessary usability attributes • Identify determinants of usability problems • Generate proper solution • Limitation • Quality analysis relies heavily on experts’ knowledge.

  30. Paper 3: Chinese Character entry for mobile phones • Object A longitudinal experiment to evaluate character entry performance using both objective and subjective measures for a new design and the existing cell phone keypad.

  31. Background Knowledge • Chinese is an iconographic language • Two primary methods for entering Chinese Characters • Pronunciation-based methods (Pinyin) • Stroke-based method Stroke: each stroke is written with a single action Chinese Characters: the minimum functional unit. Most characters are composed of two or more strokes. character strokes

  32. Current stroke input method • A single stroke is used as the legend for each key to represent the corresponding group of strokes • Problems: • Failed to convey the necessary information to all users to understand which strokes could be entered using each key. • Select the wrong key • Separate a single stroke into two or more pieces and attempt to enter each piece separately • Try to enter two or more strokes using a single key

  33. Evaluation method • Participants: • born and raised in China, • lived in the US for more than 4 years. • 24 volunteers(12 males, 12 females ) • Tasks • Text entry tasks: enter 5 sentences that were based on headlines from a Chinese news website each of the 6 days • Distracter task • Questionnaire • Procedures • Pre-test on the first day • 6 days survey • Nine-point scale • Post-test on the last day

  34. Dependent variables • Entry speed • Character-level failures • Stroke-level accuracy • Overall satisfaction • Further usage Effectiveness of two keypad design How well participants understood the system

  35. Thank you !

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