Components of HCI 吳欣潔教授朝陽科技大學工業工程與管理系民國 102 年 6 月 1
Factors in HCI design 2 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
Case1: The travel agency needs a new ticketing system-1 Current practice was manual and timeconsuming The problems were found by a sister company that was using a computerized ticketing system The computer is always going wrong They cannot understand some of the messages that it produces when they make errors A large number of staff have left the office 3
Case1: The travel agency needs a new ticketing system-2 The consultants recommend: Immediate ticket booking via a computer connection Automatic print-out of tickets, itineraries and receipts Direct connection between the booking system and accounting (speeding up the process of accounting) Elimination of booking forms 4
Case1: The travel agency needs a new ticketing system-3 The consultants suggest: Making the interface to the system mimic the noncomputerized task Making it comfortable for the sales staff to operate the computer Provideing scope for direct contact with customers Training staff Careful changes to existing jobs To know how to cope when computer malfunctions Feelings of elitism will need to be resolved 5
Exercise 1-1 A supermarket chain decides to implement a computerized system to automate checkout: A bar code reader for use at the checkout counter which provides a record of all the goods sold as well as an itemized receipt for the customer, a bar code reader with a digital display which is installed on the front of each trolley, providing the shopper with the potential for a constant update of how much all the items in the trolley will cost, a cashless paying system where only credit cards and direct debit cheque cards are allowed. 6
Exercise 1-2 Using the previous case study as a guide, try to determine the important factors that need to be taken into account when considering the implementation of the computerized system. In your analysis think about the advantages and disadvantages of introducing this nes technology. (20-min discussion) 7
A paper user interface (Figure 2.2) 8 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
A paper user interface The characteristics of the paper user interface are: the user can interact with the system via paper through the paper user interface (or electronically), a form, like the one in Figure 2.2, is presented to the user to complete and the user's details (entered via this form) provide instructions for processing documents, it has many uses, including electronic filing. 9
The disciplines that contribute to HCI 10 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
Social psychology Four core concerns of social psychology the influence of one individual on another person's attitudes and behaviour, the impact of a group on its members attitudes and behaviour, the impact of a member on a group's activities and structure, the relationship between the structure and activities of different groups. 11
A model of HCI 12 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
A model of HCI (Eason 1991) Four assumptions are made for this model people can mean one or more people, work can mean narrowly or broadly defined activities including tasks or more loosely defined activities, environment refers to the physical, organizational and social aspects of the environment, technology can be any technological artefact including any kind of computer or workstation. 13
The task-artefact cycle 14 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
How work and the design of artifacts cyclically influence each other? A task implicitly sets requirements for the development of artifacts,and the use of an artifact often redefines the task for which the artifact was originally developed [Figure 2.5]. For example, typewriting altered office tasks, word processors altered them again, desktop publishing systems altered them still more. In each case, changed tasks themselves suggested new needs and opportunities for further change. (Carroll, 1990, p.323) 15
Designing HCI When we begin to design HCI, we shall try to answer the questions: what is HCI design and how does it differ from the software engineering water fall model? who gets involved in design? what is creative design? 16
software engineering 17 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
HCI design model HCI design should: be user-centred and involve users as much as possible so that they can influence it, integrate knowledge and expertise from the different disciplines that contribute to HCI design, be highly iterative so that testing can be done to check that the design does indeed meet users requirements. 18
Who and what are involved in the design cycle? 19 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
Who and what are involved in the design cycle? 20 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
The star life cycle 21 資料出處 : Jenny Preece,1994, Human-Computer Interaction, Addison-Wesley
Other important design activities: User, work, task and environment analyses the human aspects of requirements analysis. Technical analysis, which aims to match the user requirements with the technology. Requirements specification. Design and design representation, including coding. Prototyping and use of other design support tools and techniques. Coding or implementation. 22
Key points-1 HCI is concerned with designing computer systems to match the needs of people. HCI draws from the knowledge and methods of many different disciplines, chiefly computer science, cognitive psychologr, social science and ergonomics or human factors. Computer science provides knowledge about technology and a wide assortment of software tools and methods for facilitating design and development. Cognitive psychology provides knowledge about the capabilities and limitations of users. Recent work on distributed cognition aims to model the way groups of users interact with the adefact that they use and each other in their natural environment. 23
Key points-2 Social psychology helps to explain the structure and functions of organizations through the use of techniques like ethnomethodology. Ergonomics and human factors knowledge ensures that hardware and software is designed so that it does not damage users physiologically. HCI can be viewed as a model in which people,activities (often concerned with work), technology and the environment (social, organization and physical) are closely interrelated. HCI design should be user-centred, integrate knowledge from different disciplines and be highly iterative. Evaluation forms the focal point in the star model of design, which assumes that design calls upon a variety of knowledge and methods when necessary. 24