Human-computer interaction : Introduction

Objectives

Define HCI
-Understand the taxonomy of HCI
-Describe the components of HCI
-Understand the discipline contributing to HCI
-Understand the human factors

Definitions of HCI
-HCI is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. (ACM SIGCHI, 1992, p.6)
-A set of processes, dialogues and actions through which user employs and interacts with a computer. (Baecker and Buxton, 1987, p.40)
-HCI is about designing computer systems that support people so that they can carry out their activities productively and safely. (Preece 1994)

The importance of HCI
-HCI is important in the design process since the computer interface is the first point of contact the user has with the system and the user will judge the system on the basis of the interface.

-Systems should consider some aspects of the cost:
..>The cost of software is high and the competitive edge is more difficult to achieve. The interface to a system might give it this edge.
..>The cost to train users is high, therefore, a system which is easy and natural to use will save money in the long run, since the training time will be kept to a minimum.
..>The cost of human error can be high. Systems that are transparent ought to reduce the likelihood of error or to aid error recovery.

Taxonomy of HCI

Use and context
>social organization and work
.>Humans are interacting social beings.
.>Considers models of human activity.
Small group, organizations, socio-technical systems
.>Quality of work life..

application areas
>Characteristics of application domain, e.g : individual vs group work
>Popular style
.>ocument production, tutorial and help, multimedia information kiosks, embedded systems.

human-machine fit & adaptation
>Improve the fit between the designed object and its use
>How systems are selected and adopted, how systems adapt to the user (customization), how users adapt to the system (training, ease of learning), user guidance (help, documentation, error-handling)

Human characteristics (how people work and how they are expected to interact with machines)
>human information processing
>Characteristics of the human as a processor of information
>Memory, perception, motor skills, attention, problem solving…

language, communication, and interaction
>Aspects of language
>Syntax, semantics, conversational interaction, specialized languages

ergonomics
>Characteristics of people and their relationship to workspace and the environment
>Arrangement of displays and controls, fatigue and health, design for the disable…

Computer system & interface architecture
>input & output devices
>dialogue techniques
>dialogue genre
>computer graphics
>dialog architecture

Development process
>design approaches
>implementation techniques & tool
>evaluation techniques




Disciplines contributing to HCI
.Computer Science
-To provide knowledge about the capability of technology and wide assortment of software tools.
-It also provides methods for facilitating design & development.

.Cognitive Psychology
-It provides knowledge about the capabilities & limitation of users
-Concerned with understanding human behavior such as what we see, what we touch, what we taste.

.Social and organizational psychology
-Concerned with studying the nature and causes of human behavior in a social context.
-The role of social and organizational psychology is to inform designers about social and organizational structures and about how the introduction of computers will influence working practices.

.Ergonomics
-Developed from the interests of a number of different disciplines.
-Its purpose is to define and design tools and various artifacts for different work, leisure and domestic environments to suit the capabilities and capacities of users.

Linguistics
-Is the scientific study of language
-Understanding of the syntax (structure) and semantic (meaning) is important

Artificial Intelligence
-Concerned with the design of intelligent computer programs which simulate different aspects of intelligent human behaviour.
-The relationship of AI and HCI is mainly concerned with users’ needs when interacting with an intelligent interface.

.Philosophy, sociology and anthropology
-Traditionally, they have not been directly involved with the actual design of computer systems, but rather with the consequences of developments in information technology and technology transfer.

.Engineering and design
-Engineering is the applies science which relies heavily on model building and empirical testing. its takes the findings of science and utilizes them in the production of artifacts.
-Design contributes creative skills and knowledge to this process.

Human Factor (Ergonomics)

"The scientific study of the relationship between human and their work environment" (Murrell, 1965; Chapanis, 1965)

.Is the study of the physical characteristics of the interaction:
-How the controls are designed
-The physical environment in which the interaction takes place
-The layout and physical qualities of the screen.

Issues Addressed by Ergonomics
-Arrangement of controls and displays
-Sets of controls and parts of the display should be grouped logically to allow rapid access by the user.
-Should be organized in terms of
...Functionality – controls and displays are organized so that those that are functionally related are placed together
...Sequential - controls and displays are organized in a particular task sequence.
...Frequency - controls and displays are organized based on the frequency of used

The physical environment of the interaction
-Where will the system be used
-By whom will it be used
-Will users be sitting, standing or moving about
-Considerations
..Size
The smallest user should be able to reach all the controls (this may include a user in a wheelchair), and the largest user should not be cramped in the environment. In particular, all users should be comfortably able to see critical displays.
..Seat
For long period of use, the user should be seated for comfort and stability, and seating should provide back support.
..Stand
If required to stand, the user should have room to move around in order to reach all the controls.

Health Issues
-These are the factors in the physical environment that directly affect the quality of the interaction and the user's performance :
...Physical Position
...Temperature
...Lighting
...Noise
...Time

The use of colour
-Importance of Arrangement of Control and Displays
...Give strong emotional reaction
...Add accents to an uninteresting display
...Facilitate subtle discrimination in complex displays
...Emphasize the logical organization of information
...Draw attention to alert the users