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  1. Human Computer Interaction Lecture Notes
  2. HUMAN COMPUTER INTERACTION Csc 306 Source: VU, Lora Aroyo Adewale V.A. Lecture 1
  3. Course OUTLINE • Introduction to HCI • Design process/Good and poor design • Usability engineering concept • Usability engineering life cycle • Goal Oriented interaction design • Implementation support tools • Usability evaluation • Ubiquitous computing • Groupware • Virtual and Augmented Reality • Collaborative work • Hypertext and multimedia • Cognitive models
  5. yo, Web & Media Group Human-Computer Interaction Dashboards Lora Aro 5
  6. Human-Computer Interaction Lora Aroyo, Web & Media Group 7
  7. Human-Computer Interaction Wearables Lora Aroyo, Web & Media Group 8
  8. Human-Computer Interaction Sensing Affect Blood Volume Pressure (BVP) earring Interactive Pillow as a TV remote control Galvanic Skin Response (GSR) rings and bracelet Lora Aroyo, Web & Media Group 9
  9. “Avengers” (2012 Human-Computer Interaction Speech, Mobile & Augmented Interaction “Minority Report” (2002) “Her” (2014) “Star Trek: In to the Darkness” (2013) ) “Star Trek: TOS” (1967) Lora Aroyo, Web & Media Group
  10. Lora Aroyo, Web & Media Group Human-Computer Interaction Virtual Reality 11
  11. 12 eb & Human-Computer Interaction Interactive Workspaces Mimio Stanford Interactive Workspaces Project BendDesk Lora Aroyo, Web & Media Group
  12. Human-Computer Interaction WHY HCI?
  13. • How many interactive products are there in everyday use? Think for a minute about what you use in a typical day: – cell phone, computer, personal organizer, remote control, soft drink machine, coffee machine, ATM, ticket machine, library information system, the web, photocopier, watch, printer, stereo, calculator, video game.. . the list is endless. • Now think for a minute about how usable they are. How many are actually easy, effortless, and enjoyable to use? All of them, several, or just one or two? This list is probably considerably shorter. Why is this so? Human-Computer Interaction
  14. y s e Human-Computer Interaction Typical Frustrations Can’t figure out how to simple things do Many not frequent use functions Man hidden functions Operation outcom not visible Can’t remember combinations of digits * # how do we know whether it worked how can we remember that this option is ON Lora Aroyo, Web & Media Group 14
  15. Definition of HCI by ACM 15 “Human Computer Interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use as well as the major phenomena surrounding the it.” Human-Computer Interaction
  16. Goals of HCI (1) • The goals of HCI are to produce usable and safe systems, as well as functional systems. • In order to produce computer systems with good usability, developers must attempt to: – Understand the factors that determine how people use technology – Develop tools and techniques to enable building suitable systems – Achieve efficient, effective, and safe interaction – Put people first 16 Human-Computer Interaction
  17. Goals of HCI (2) • Underlying the whole theme of HCI is the belief that people using a computer system should come first. • Their needs, capabilities and preferences for conducting various tasks should direct developers in the way that they design systems. • People should not have to change the way that they use a system in order to fit in with it. • Instead, the system should be designed to match their requirements. 17 Human-Computer Interaction
  18. Goals of HCI (3) To develop or improve the • Safety • Utility • Effectiveness • Efficiency • Usability • Appeal . . . of systems that include computers 18 Human-Computer Interaction
  19. User-Centered Development Methodology • Traditional software engineering methods arose in 1960s and 1970s – Systems were not highly interactive – End-user were computer specialists  Issues concerning end-user and usability were not at all important  user interface design not considered explicitly • Now: – Most end-users are not computer specialists – Usability vital for success 19 Human-Computer Interaction
  20. System –Centred Design • Traditional System-Centered design: – Emphasis on the functionality, – UI is added at the end – Emphasis on correct software rather than on ease of use – User has to adapt himself to the system 20 Human-Computer Interaction
  21. User-Centre design • Things are changing: User-Centered design – User Interface more important – Emphasis on end-users’ tasks, – Early end-user participation: in analysis and design – Evaluation by end-users – Consequences: • more work for User Interface designer and User Interface programmer 21 Human-Computer Interaction
  22. Factors in HCI (1) • There are a large number of factors which should be considered in the analysis and design of a system using HCI principles. • Many of these factors interact with each other, making the analysis even more complex. 22 Human-Computer Interaction
  23. Factors in HCI (2) • Organisation Factors Training, job design, politics, roles, work organisation • Environmental Factors Noise, heating, lighting, ventilation Health and Safety Factors • The User Cognitive processes and capabilities Motivation, enjoyment, satisfaction, personality, experience 23 Human-Computer Interaction
  24. Factors in HCI (3) • Comfort Factors Seating, equipment, layout. • User Interface Input devices, output devices, dialogue structures, use of colour, icons, commands, navigation, graphics, natural language, user support, multimedia • Task Factors Easy, complex, novel, task allocation, monitoring, skills 24 Human-Computer Interaction
  25. Factors in HCI (4) • Constraints Cost, timescales, budgets, staff, equipment, buildings • System Functionality Hardware, software, application • Productivity Factors Increase output, increase quality, decrease costs, decrease errors, increase innovation 25 Human-Computer Interaction
  26. Fields that contribute to HCI (1) • Computer Science – Implementation of software • Engineering – Faster, cheaper equipment • Ergonomics – Design for human factors 26 Human-Computer Interaction
  27. Fields that contribute to HCI (2) • Graphic design – Visual communication • Technical writing – Textual communication • Linguistics, artificial intelligence – Speech recognition, natural language processing 27 Human-Computer Interaction
  28. Fields that contribute to HCI (3) • Cognitive psychology – Perception, memory, mental models • Sociology – How people interact in groups • Anthropology – Study of people in their work settings 28 Human-Computer Interaction
  29. Human-Computer Interaction Link to Software Engineering • Separate but related concerns: vs. user Some overlap in techniques – Use cases – Iterative file cycle systems • • Multi-disciplinary nature of HCI Lora Aroyo, Web & Media Group 20
  30. Human-Computer Interaction Traditional Life Cycle Lora Aroyo, Web & Media Group 21
  31. Human-Computer Interaction Evaluation-Centered Equally supportive of – top-down & bottom-up inside-out & outside-in development – Lora Aroyo, Web & Media Group 22
  32. Human-Computer Interaction Iterative Model Lora Aroyo, Web & Media Group 23
  33. Design Process/Good and Poor Design
  34. The Psychology of Usable Things “ When simple things need pictures, labels, or instructions, the design has failed. ”
  35. WHAT IS DESIGN? • A simple definition of design is: – achieving goals within constraints • Goal: is the purpose of the design intended to be produced with the users and user needs in mind. • Constraints: include materials to be used, standards to adopted, the cost, time needed for development as well as the health and safety issues attached to the system.
  36. Affordance • An affordance is the possibility of an action on an object or environment. • Affordances are the range of possible (physical) actions by a user on an artefact: 36
  37. Two types of Affordances • Perceived Affordances: are the actions a user perceives to be possible. • Real Affordances: are the actions which are actually possible. HCI LECTURE 2 37
  38. Perceived Affordance • Perceived affordance is the quality of an object that suggests how it might be used. • In screen-based communications, the concept of perceived affordance is useful when designing or evaluating a graphical user interface (GUI). • HCI LECTURE 2 38
  39. Example of Affordance 39 Jug and Tea Cups • Real Affordance: Jugs are used for serving tea, while tea cups are used for drinking tea • Perceived Affordance: Jugs can be used for drinking tea and tea cups for drinking wine
  40. Other examples of Affordances • For physical objects, there can be both real and perceived affordances (and the two sets are not necessarily the same). • Appearance indicates how to use something: – A chair affords (suggests) sitting. – Knobs are for turning. – Slots are for inserting things. – A button affords pushing. When perceived affordances are taken advantage of, The user knows what to do just by looking. HCI LECTURE 2 40
  41. Ambiguous Affordances • These two doors are examples of ambiguous affordances in door design. • The affordances for these door seem reasonable within themselves. • Context is everything. HCI LECTURE 2 41
  42. HCI LECTURE 2 42
  43. Good Design HCI LECTURE 2 43
  44. Mappings • Mappings are the relationships between controls and their effects on a system. • Types of Mapping – Arbitrary Mapping (requires the use of label and memory) – Paired Mapping (Confusion can still occur) – Full Natural Mapping (No ambiguity, no need for learning or remembering, and no need for labels) • Question: – How should one arrange the hot plate controls on a cooker? 44
  45. Constraints • The difficulty of dealing with a novel situation is directly related to the number of possibilities. • Constraints are: – Physical – Semantic – Cultural – Logical • These constraints limit on the number of possibilities. 45
  46. Examples of Constraints – Physical constraints such as pegs and holes limit possible operations. – Semantic constraints rely upon our knowledge of the situation and of the world. – Cultural constraints rely upon accepted cultural conventions. – Logical constraints exploit logical relationships. For example a natural mapping between the spatial layout of components and their controls. • Where affordances suggest the range of possibilities, constraints limit the number of alternatives. 46
  47. 47 Motorbike toy with 12 parts.
  48. Constraints make its construction simple, even for adults! –Physical: Front wheel only fits in one place. –Semantic: The rider sits on the seat facing forward. –Cultural: Red is a rear light, yellow a front light. –Logical: Two blue lights, two white pieces, probably go together. 48
  49. The Motor Bike HCI LECTURE 2 49
  50. Conventions • Conventions are cultural constraints. • They are initially arbitrary, but evolve and become accepted over time. • They can however vary enormously across different cultures, for example: – Light switches: • America down is off • Britain down is on 50
  51. The Structure of Human Memory • Short-Term Memory (STM) • Short-term memory is the memory of the present, used as working or temporary memory. – Information is retained in STM automatically and is retrieved without effort. – However, the amount of information in STM is severely limited. – STM is extremely fragile – the slightest distraction and its contents are gone. • For example, STM can hold a seven digit phone number from the time you look it up until the time you use it, as long as no distractions occur. 51
  52. The Structure of Human Memory ctd. • Long Term Memory (LTM) • Long-term memory is the memory of the past. –It takes time to put things into LTM and time and effort to get things out. –Capacity is estimated at about 100 million items. 52
  53. Knowledge in the Head and in the World • Not all of the knowledge required for precise behaviour has to be in the head. • It can be distributed: –partly in the head –partly in the world –and partly in the constraints of the world. 53
  54. HCI Software Process
  55. HCI Software Process • The Software Process in HCI involves 1. Software Development Life Cycle • Find out the process of SDLC and the models used 2. Usability Engineering Life Cycle
  56. The Usability Engineering Lifecycle 1. Know the User 2. Usability Benchmarking 3. Goal-Oriented Interaction Design 4. Iterative Design: (a) Prototyping (b) Formative Usability Evaluation (Inspection and/or Testing) 5. Usability Evaluation 6. Follow-up Studies 56 HCI Lecture 3 Usability Engineering Concepts
  57. Know the Users • Identification of users can be classified according to their: –Experience –Educational level –Age –Amount of prior training HCI Lecture 3 Know the User 57
  58. Usability Benchmarking • This describes the standard of the new system to be developed in comparison to the existing standards. • Raising the standard or maintaining the existing standard is also put into consideration in the interface design of the system. • The return on investment (i.e. profit margin) of the new system would be part of the benchmarking. HCI Lecture 3 Usability Benchmarking 58
  59. Goal-Oriented Interaction Design • The software is designed based on an understanding of human goals and associated tasks. • What is a goal? • A goal is a final purpose or aim, an objective. • Tasks are particular ways of accomplishing a goal. • There may be multiple ways of achieving a goal. Goal Oriented Interaction Design 59
  60. Example of goal and tasks • Goal: Get something to eat. • Task: Go to the restaurant around the corner. • Task: Call small chops service. • Task: Go to the market, buy ingredients, and cook for self. • Too often, software designers focus on simplifying a task, rather than accomplishing a goal. • Tasks are means to an end, not an end in themselves. 60
  61. Six Attributes of Usability of a System • (1) Effectiveness: completeness with which users achieve their goal. • (2) Learnability: ease of learning for novice users. • (3) Efficiency: steady-state performance of expert users. • (4) Memorability: ease of using system intermittently for casual users. • (5) Errors: error rate for minor and catastrophic errors. • (6) Satisfaction: how satisfying a system is to use, from user’s point 61 HCI Lecture 4 Usability Engineering Concepts
  62. 9 A model of factors contributing to usability usability enjoyability satisfaction acceptability ergonomics primary functionality efficiency of use extensibility/customization learnability ease of use familiarity fit to task fit to user cognitive load error handling HCI Lecture 3 Usability Engineering Concepts
  63. 10 Usability Principles 1. Do not rely only just on usability guidelines – always test with users. – Usability guidelines have exceptions; you can only be confident that a UI is good if you test it successfully with users. 2. Ensure that the sequences of actions to achieve a task are as simple as possible. – Reduce the amount of reading and manipulation the user has to do. – Ensure the user does not have to navigate anywhere to do subsequent steps of a task. HCI Lecture 3 Usability Engineering Concepts
  64. 11 Usability Principles 3. Ensure that the user always knows what he or she can and should do next – Ensure that the user can figure out the affordance (what commands are available and are not available). – Make the most important commands stand out. 4. Provide good feedback including effective error messages. – Inform users of the progress of operations and of their location as they navigate. – When something goes wrong explain the situation in adequate detail and help the user to resolve the problem. HCI Lecture 3 Usability Engineering Concepts
  65. 12 Usability Principles 5. Ensure that the user can always get out, go back or undo an action. – Ensure that all operations can be undone. – Ensure it is easy to navigate back to where the user came from. 6. Ensure that response time is adequate. – Users are very sensitive to slow response time • They compare your system to others. – Keep response time less than a second for most operations. – Warn users of longer delays and inform them of progress. HCI Lecture 3 Usability Engineering Concepts
  66. Implementation Support -Tools
  67. Technology Supporting User Interface. • Input Devices. • Output Devices. • High-speed Processing. • Networking. 67
  68. Technology Supporting User Interface. • Input Devices. – Keyboard. – Pointing devices. – 3D Input. – Recognized Input. 68
  69. Technology Supporting User Interface. • Input Devices. – Keyboards. • QWERTY • DVORAK • Split 69
  70. Technology Supporting User Interface. • Input Devices. – POINTING DEVICES • Mouse • Trackball • Touch-screen 70
  71. Technology Supporting User Interface. • Input Devices. – 3D Input. • Data Glove • 3D-Mouse 71
  72. Technology Supporting User Interface. • Input Devices. – Recognized Input. • OCR • Eye-Gaze • Barcode Scan 72
  73. Technology Supporting User Interface. • Output Devices. – CRT. – LCD. – Sound. – Printers – 3D display 73
  74. Computers vs. Humans • Computers do not work like humans. • One part of software, the inside, must be written in harmony with the demands of hardware • The other side of software, the outside, must be written in harmony with the demands of human nature. 74
  75. Differences between computers and humans Computers Humans Incredibly Fast Incredibly Slow Error Free Error Prone Deterministic Irrational Apathetic Emotional Literal Inferential Sequential Random Predictable Unpredictable Amoral Ethical Stupid Intelligent 75
  76. Prototyping • In increasing order of complexity: • Verbal Prototypes: textual description of choices and results. • Paper Prototypes: • Low-Fidelity: hand-drawn sketches. • High-Fidelity: more elaborate printouts. • Interactive Sketches: interactive composition of hand-drawn sketches. • Working Prototypes: interactive, skeleton implementation. 76
  77. Verbal Prototype • Simple textual description of choices and results. • Write the user guide first, before anything is implemented. Have it reviewed by someone else. HCI Lecture 8 Prototyping 77
  78. Paper Prototypes • Paper prototypes simulate screen and dialogue elements on paper. • First hand-drawn sketches (lo-fi), later perhaps more elaborate printouts (hi-fi). • Greeking (drawing squiggly lines) is used to represent text which would otherwise be a distraction. 78
  79. Interactive Sketches • Scan in hand-drawn interface sketches. • Assemble interactive prototype with clickable elements. • Retains throwaway, casual look to encourage criticism and discussion, as shown in Figure 6. 79
  80. Interaction Design versus Interface Design • Interface design suggests an interface between code on one side and users on the other side and passing messages between them. • Interaction design refers to function, behaviour, and final presentation of a system 80
  81. Usability Evaluation
  82. Usability Evaluation – Four Types • Exploratory - how is it (or will it be) used? • Predictive - estimating how good it will be. • Formative - how can it be made better? • Summative - how good is it? 82
  83. Usability Evaluation Methods • The methods of usability evaluation can also be classified according to who performs them: • Usability Inspection Methods – Inspection of interface design by usability specialists using heuristics and judgement (no test users). • Usability Testing Methods – Empirical testing of interface design with real users. 83
  84. Usability Inspection Methods • Inspection methods of interface design use heuristic methods based on analysis and judgement rather than experiment. • Theses methods are: • 1. Heuristic Evaluation: A small team of evaluators inspects an interface using a small checklist of • general principles and produces an aggregate list of potential problems. • 2. Guideline Checking: An evaluator checks an interface against a detailed list of specific guidelines and produces a list of deviations from the guidelines. 84
  85. • 3. Cognitive Walkthrough: A small team walks through a typical task in the mind set of a novice user and produces a success or failure story at each step along the correct path. [analyses learnability] • 4. Guideline Scoring: An evaluator scores an interface against a detailed list of specific guidelines and produces a total score representing the degree to which an interface follows the guidelines. 85
  86. • 5. Action Analysis: An evaluator produces an estimate of the time an expert user will take to complete a given task, by breaking the task down into even smaller steps and then summing up the atomic action times. [analyses efficiency] 86
  87. Usability Testing Methods • “ Would you fly in an airplane that has not been flight tested? Of course not. • So you should not be using software that has not been usability tested. ” 87
  88. Why do Usability Testing? • More often than not, intuitions are wrong! • People believe they understand behaviour of others based on their own experiences. • This belief only lost through prediction if there is no measurement (! usability tests). • Designers of system find it very easy to use. • Experience changes one’s perception of the world. • It is almost impossible to “forget” an experience and put oneself in position of someone not having had the same experience. 88
  89. Usability Testing Methods • Empirical testing of interface design with representative users. • (i) Thinking Aloud: Test users verbalise thoughts while performing test tasks. • (ii) Co-Discovery: Two test users explore an interface together. Insight is gained from their conversation while performing test tasks. • (iii) Formal Experiment: Controlled experiment, face-to-face with test users, measurements and statistical analysis. • (iv) Query Techniques: Interviews and Questionnaires • (v) Usage Studies: Usage data is collected from a small number of users working on their own tasks in their natural environment over a longer period. 89