Chapter+2


 * toc**

People use technologies to undertake activities in context. e.g. teenagers use cell phones to send text messages to their friends while sitting on a bus, secretaries’ use Microsoft word to write documents in a firm…

If the technology is changed then the nature of the activities will also change ex. the changing nature of telephoning activity as technology changes from switch board to land line to cell phone

**//People//**
> > >> > >> > > >>
 * //Physical differences//: height, weight, personalities, different cognitive skills and preferences, variability in the five senses; touch, smell, sight, hearing, taste --> huge effect on how accessible, usable and enjoyable using a technology will be for the people in different contexts.
 * //Psychological differences//:
 * ex. people with good spatial ability will find it much easier to find their way around and remember a website that those with poor ability.
 * Designers should design for people with poor ability by providing good sinage and clear directions.
 * People also have different needs and abilities when it comes to attention and memory and these can change depending on factors such as stress and tiredness
 * //Usage differences://
 * Novice and expert users of technology will typically have very different requirements, where experts use a system regularly and learn all sorts of details, a novice user of the same system will need to be guided through an interaction.
 * Designing for homogeneous groups of people- groups who are broadly similar and want to do much the same things- is quite different from designing for heterogeneous groups (secretaries or managers or laboratory scientist...)

10 important characteristics of activities that designers need to consider:
 * Activities**


 * · Temporal aspects (items 1-4)**
 * · Cooperation (5)**
 * · Complexity (6)**
 * · Safety-critical (7-8)**
 * · The nature of the content (9 and 10)**

1. Temporal aspects cover how regular or infrequent activities are. Designers should ensure that frequent tasks are easy to do, but they also need to ensure that infrequent tasks are easy to learn or remember how to do 2. Time pressures, peaks and troughs of working. A design that works well when things are quiet can be awful when things are busy 3. If people are interrupted when undertaking some activity, the design needs to ensure that they can find their place again and pick up 4. The response time...as a general rule people expect a response time of about 100 milliseconds for hand-eye coordination activities and one second for a case-effect relationship such as clicking 5. Issues of awareness of others and communication and coordination are important 6. Well-defined tasks need different designs from more vague tasks 7. Some designs are safety critical, in which any mistake could result in an injury or serious accident 8. It is vital for designers to think about what happens when people make mistakes and errors and to design for such circumstances 9. Data requirements of the activity. If a large amount of alphabetical data have to be inputted as part of the activity (recording names, addresses etc.) then a keyboard is almost certainly needed 10. The importance of the media that an activity requires. A simple two tone display of numeric data demands a very different design from a full motion multimedia display

**//Contexts//**
>
 * //Physical Environment:// The environment may be very noisy, cold, wet, or dirty. e.g. the sun shining on an ATM display may make it unreadable.
 * //Social Context:// Social norms may dictate the accessibility of certain designs. Example the use of sound output is often unacceptable in an open-plan office environment, but might be quite effective where a person is working alone.
 * //Organizational Context:// is important as changes in technology often alter communication and power structures and may have effects on jobs such as deskilling.

**//Technologies//**
Interactive systems typically consist of hardware and software components and transform some input data into some output data. They can perform various functions and typically contain a good deal of data, or info content. People using such systems engage in interactions and physically devices have various degrees of style and aesthetics. Some important features of technologies are: >
 * //Input//: how people enter data and instructions into a system securely and safely.
 * //Output//: characteristics of displays using different media (e.g. video vs. photographs, speech vs. screen)
 * //Communication//: between people and between devices need to be considered. e.g. bandwidth, speed, feedback to people so that they know what is going on and indeed that something is going on!
 * //Content//: concerns the data in the system and the form it takes. Good content is accurate, up-to-date, relevant and well presented.

**Activities in Design**
There are 5 activities involved in the design process (Gillian Crampton Smith and Philip Tabor (1996)):
 * //Understanding//: where designers **observe and analyze** the information or the problem
 * //Abstracting//: where the designer **focuses on the main elements** of a problem and on the kind of information.
 * //Structuring//: where the designer considers the //relationships// between the elements and what people are interested in.
 * //Representing//: concerned with how the structure can be represented.
 * //Detailing//: concerned with what colour an item should be, how elements can move, etc.