Chapter 1 principle and guidlines

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Chapter 1 principle and guidlines

  1. 1. HUMAN COMPUTERINTERACTIONSubject Code : DCM 214 CHAPTER 1 PRINCIPLE AND GUIDLINES Prepared by : NURAINI MOHD GHANI 1
  2. 2. Related Fields"Human-computer interaction is a discipline concerned with the design, evaluation andimplementation of interactive computing systems for human use and with the study of majorphenomena surrounding them." Association for Computing Machinery–Equivalent terms are CHI and MMI–Usability Engineering focuses on design and implementation processEarlier fields of Human Factors & Ergonomics–More stress on physical issues; and on optimising (work) processes; concernsinteraction with all kinds of human artifactsUser Interface Design–Focus on interface, i.e. tends to assume deeper function is fixedUser/Human Centred Design–Approach to software engineering with user focus at all stages–Participatory Design explicitly includes users in design processInteraction Design–Wider scope than computer, and more emphasis on cognitive/experiential factors than traditional HF. Prepared by : NURAINI MOHD GHANI 2
  3. 3. HCI in the design processWaterfall Model Prepared by : NURAINI MOHD GHANI 3
  4. 4. HCI in the design process The spiral lifecycle model (Boehm, 1988) ; Importance of interaction in good design. Prepared by : NURAINI MOHD GHANI 4
  5. 5. HCI in the design process Agile development e.g. eXtreme Programming (agilemanifesto.org): emphasises tight iteration in short timescales, close collaboration with customer Prepared by : NURAINI MOHD GHANI 5
  6. 6. General Framework Task Articulation Performance Input Human Computer Output Observation Presentation Interface Complex problem : we don’t have a full of the part, or their interaction. Note that a particular desired outcome may be achieved by changing any one of these factors or interaction. Prepared by : NURAINI MOHD GHANI 6
  7. 7. Why is interaction difficult?Examples of errors Prepared by : NURAINI MOHD GHANI 7
  8. 8. Why is interaction difficult?The problem from the human perspective Prepared by : NURAINI MOHD GHANI 8
  9. 9. Why is interaction difficult? The problem from the human perspective This is called the ‘Action Cycle’ following Norman (1988) Prepared by : NURAINI MOHD GHANI 9
  10. 10. Norman’s Action CycleNorman proposed thatactions are performed incycles:1.Establish a goal2.Execute the action3.Evaluate the action Prepared by : NURAINI MOHD GHANI 10
  11. 11. Norman’s Action Cycle2.Stages of execution A. Form a plan for the task, a sequenceof system operations to be performed onsystem entities . B. Translate the plan into an actionspecification consistent with theinterface ‘input’ language. C. Output the action specificationas a sequence of lexical tokens using thesystem input devices. Prepared by : NURAINI MOHD GHANI 11
  12. 12. Norman’s Action Cycle3.Stages of evaluationD. Observe the systemresponse as e.g., visual,auditory tokensgenerated by outputdevices .E. Interpret the output interms of changes in thesystem state, e.g.,entity properties.F. Determine whether thenew system state isconsistent with what wasintended Prepared by : NURAINI MOHD GHANI 12
  13. 13. Errors Prepared by : NURAINI MOHD GHANI 13
  14. 14. Errors Prepared by : NURAINI MOHD GHANI 14
  15. 15. Errors Prepared by : NURAINI MOHD GHANI 15
  16. 16. Design Rules for HCI#Many sets of rules have been proposedto encapsulate understanding and bestpractice–Operate at various levels#principles–abstract design rules–“an interface should be easy to navigate”#guidelines–advice on how to achieve principle–may conflict; understanding theory helps resolve–“use colour to highlight links”#standards–specific rules, measurable–“MondoDesktop links are RGB #1010D0” Prepared by : NURAINI MOHD GHANI 16
  17. 17. Design Rules for HCI ISO 9241, Ergonomic of Human System Interaction, adopt traditional usability categories with specific measure. E.g.: Usability Effectiveness Efficiency Satisfaction Objective measures measures measures Suitability for the Percentage of goal Time to complete a Rating scale for task achieved task satisfaction Appropriate for Number of power Efficiency relative to Rating scale for ease trained users features used expert user of learning Lean ability Percentage of Time to learn Rating scale for ease functions learned criterion of learning Error tolerance Percentage of error Time spent on Rating scale for error corrected correcting errors handling successfully Prepared by : NURAINI MOHD GHANI 17
  18. 18. Design Rules for HCI Shneiderman’s 8 Golden Rules (1987) : *Strive for consistency *Enable frequent users to use shortcuts *Offer informative feedback *Design dialogs to yield closure *Offer error prevention and simple error *Permit easy reversal of actions *Support internal locus of control *Reduce short-term memory load Prepared by : NURAINI MOHD GHANI 18
  19. 19. Design Rules for HCI Norman’s 7 principles (1988): *Use both knowledge in the world and knowledge in the head *Simplify the structure of tasks *Make things visible *Get the mappings right *Exploit the power of constraints, both natural and artificial *Design for error *When all else fails, standardize Prepared by : NURAINI MOHD GHANI 19
  20. 20. Design Rules for HCI Nielsen’s 10 usability Heuristics (1994): *Visibility of system status *Match between systems and the real world *User control and freedom *Consistency and standard *Help users recognize, diagnose and recover from error *Error prevention *Recognition rather than recall *Flexibility and efficiency of use *Aesthetic and minimalist design *Help and documentation Prepared by : NURAINI MOHD GHANI 20
  21. 21. Consolidate the three lists here. Markany you don’t understand with *Eg : Consistency (Nor 7, Shn1, Nie 4) Prepared by : NURAINI MOHD GHANI 21
  22. 22. Usability Principle form DixChapter7 Learn ability *the ease with which new users can begin effective interaction and achieve maximal performance Flexibility *the multiplicity of way the user and system exchange information Robustness *the level of support provided to the user in determining successful achievement of goal- directed behavior Prepared by : NURAINI MOHD GHANI 22
  23. 23. Where do these rules come from? Many seem like common sense - but often violated *Home exercise :pick one everyday object and one piece of software and assess with respect to these rules. Some are grounded in our understanding of how humans perceive, think and learn. Some are the result of empirical study. Some are derived from particular characterisations of the nature of human action Some are collection of experience In this course we will study the background and justification of these rules and elaborate on how the can be applied in specific contexts. Prepared by : NURAINI MOHD GHANI 23
  24. 24. THANK YOU SEE YOU NEXT CLASS ANDDON’T FORGET FINISH YOUR HOMEWORK Prepared by : NURAINI MOHD GHANI 24

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