1. IEEM 552 - Human-Computer Systems Dr. Vincent Duffy - IEEM Week 9 - Approaches to Human- Computer Interaction Mar. 30, 1999 http://www-ieem.ust.hk/dfaculty/duffy/552 email: vduffy@ust.hk 1

2. Why do we study H-C systems? v We likely ask two questions: –How can an interactive system be developed to ensure its usability? –How can usability of an interactive system be demonstrated or measured? 4

3. What is our perspective? v Share others perspectives –‘Fighting for the user’ - Schneiderman –frustration and anxiety are a part of daily life for many users of computerized systems 5

4. What do we hope to improve? v research has shown techniques to improve: –learning time –performance speed –error rates –user satisfaction –all related to usability 6

5. Difficulties of learning the field? v From what perspective do we view it? –design –implementation –managing –maintenance –training –system/interface refinement –evaluation v Each perspective brings a different set of expertise 7

6. What backgrounds are represented? v researchers may be from: –computer science –psychology –human factors and ergonomics –education –management –information systems/science –virtual reality v All want to understand complex interaction of people and machines/systems 8

7. research paper systematically v emphasis on theory/approaches to HCI –not emphasis on technology v empirical –various interactive methods evaluated by testing v cognitive –assists human problem solving v predictive modeling –tools to predict best method prior to development v anthropomorphic –make computers easy as interaction w/humans 9

8. Empirical approach v Evaluate choices –displays, input devices –correct choice by experimentation –Ch.6 (hazards), 4, 5 v advantage: –alternative to intuition gauging effectiveness by measurement, solve a need v disadvantage: –dangers of improper study lack of theoretical guidance –empirical can not answer questions such as: u ‘when does a novice change to expert?’ 10

9. Cognitive approach v how does the human perceive, store, retrieve, manipulate info, solve problems v theories include: –analogical reasoning –eg. metaphors –spatial reasoning –problem solving –human attention modeling –use of visual images 11

10. Cognitive approach v mental models (ch.7), cognitive goals, human information processor, neural network, metaphors, spatial reasoning and graphics (ch.11) v mental model - –built/developed by user through interactions w/display v developer’s conceptual model –accurate & complete underlying model of the system v advantage: –views user as flexible information processor solving problems v disadvantage: –sometimes approach not well defined enough to offer suggestions 12

11. Modified Fig.3.1 Conceptualization of design of interfaces Conceptual model of the developer Mental model Interface design of the user 13

12. Predictive modeling v Performance of humans interacting w/computers –similar to civil engr.: model bridge before building –general classes include u information processing (Card, Moran, Newell) u GOMS (goals, operators, methods, selection of rules) - previously used for analyzing text editing u rules of information processing, language v advantage: –accurate error & time estimates for task v disadvantage: –implementation requires interpretation 14

13. Anthropomorphic v Application of human qualities to non- human entities –humans can communicate w/humans –computer does not act enough like human –ex. natural language, voice communication, help messages, etc., task analysis to find mismatches 15

14. Integration for design cycle v global/system design -all 4 v task analysis – anthropomorphic v conceptual model, prototype construction – cognitive v alternate designs to help eliminate complexities – predictive v user testing & evaluation, – empirical 16

15. Re: paper using natural language conventions…in design of speech recognition systems v Wizard of oz method –see pg. 460-462 text

16. In the coming weeks v tentatively v Wk10 13 apr - ‘mental workload’ –meet in I.S. lab first v wk11 20 apr - ‘interpreting results’ v wk12 27 apr - Visual C++ demo v wk13 4 may - intro to final project v wk14 11 may - ‘working in groups’ v wk15 18 may - project presentations v wk16 25 may -final exam - rm2302 6:45-9:30

17. Homework for next week v Please submit by email by Tuesday 13 april at noon –redo question 7a from exam u if you scored 5 points…continue to elaborate v 7a. (5 points) Consider the paper ‘A Study on Prevalence of Musculoskeletal Discomfort Among Visual Display Terminals in Hong Kong’ by W.S. Tang and the presentation by Dr. Kumashiro ‘A Strategy for Achieving Productive Aging in Industries’. v v Consider the findings/results of the study by Tang and tell how you would use the model/checklist by Dr. Kumashiro to improve the working life of ‘Aging VDT Users’ in Hong Kong. Give a specific result from Wong’s study and related it to a specific example from Kumashiro’s work. v read chapter 12. Workload assessment, in Eberts v read paper Miller and Stanney, IJHCI about the Windows computer experience questionnaire v p.460-463, Eberts, ‘Wizard of Oz’ methodology

18. Exam scores v Average 88 v 95+ A+ v 90-94 A v 89 A- v 86-88 B+ v 80-85 B v 70-79 C