4. 4
Definition
Design can be defined as achieving goals
within constraints.
Goals
• What is the purpose of the design we are intending to
produce?
• Who is it for?
• Why do they want it?
•Constraints
• What materials must we use?
• What standards must we adopt?
• How much can it cost? How much time do we have to
develop it?
5. 5
Golden Rule of Design
The golden Rule of design is to understand your material. The
material been used here refers to the things needed to
accomplish the design process.
In interactive Design the material refers to
– Human
– Computers
To consider the golden rule of design it means we must
understand human and Computers.
6. 6
Design Process
In order to design something we must undergo certain processes.
Here we’ll take a simplified view of four main phases plus an
iteration loop, focused on the design of interaction
7. 7
Design Process cont
In consideration of the design Process diagram we can therefore consider the
phases as follows:
Requirements
Analysis
Design
Evaluation (Prototype evaluation)
Implementation
8. 8
Requirements
Requirements simply means looking for what you
wanted.
The first stage of the design process is establishing
what exactly is needed. Or identifying what exactly
you want the system to accomplish.
There are a number of techniques used for this in
HCI:
– interviewing people,
– videotaping them,
– looking at the documents and objects that they work
with,
– observing them directly.
9. 9
Requirements
In order to get good design you must first understand the
requirements. We will consider several approaches that
will help us get the requirements: socio-technical
modeling, soft systems methodology, participatory design,
ethnographic methods and contextual inquiry.
Before we look in more detail at these approaches we need
to clarify what we mean when we talk about
‘stakeholders’.”
10. 10
Stakeholders
• Understanding stakeholders is key to many of the
approaches to requirements capture, since in an
organizational setting it is not simply the end-user who
is affected by the introduction of new technology.
• Stakeholder, therefore, can be defined as anyone who is
affected by the success or failure of a system.
• Stakeholders can be categorized into:
– Primary stakeholders are people who actually use the system
– the end-users
11. 11
Stakeholders
•Stakeholders can be categorized into:
– Primary stakeholders are people who actually use the system
– the end-users
– Secondary stakeholders are people who do not directly use
the system, but receive output from it or provide input to it
(for example, someone who receives a report produced by the
system).
– Tertiary stakeholders are people who do not fall into either of the first
two categories but who are directly affected by the success or failure of
the system (for example, a director whose profits increase or decrease
depending on the success of the system).
– Facilitating stakeholders are people who are involved with the design,
development and maintenance of the system.
12. 12
Socio Technical Models
Socio-technical models for interactive systems are therefore
concerned with technical, social, organizational and human aspects
of design. They recognize the fact that technology is not developed
in isolation but as part of a wider organizational environment. It is
important to consider social and technical issues side by side so that
human issues are not overruled by technical considerations.
In this we will consider two socio technical models that can be used
to capture the user requirements.
– CUSTOM models
– OSTA model
13. 13
CUSTOM model
CUSTOM model is a socio-technical methodology designed to be
practical to use in small organizations.
It is based on the User Skills and Task Match (USTM) approach,
developed to allow design teams to understand and fully document
user requirements.
It is a forms-based methodology, providing a set of questions to
apply at each of its stages. There are six key stages to carry out in a
CUSTOM model :
14. 14
CUSTOM model
1. Describe the organizational context, including its primary goals,
physical characteristics, political and economic background.
2. Identify and describe stakeholders. All stakeholders are named,
categorized (as primary, secondary, tertiary or facilitating) and
described with regard to personal issues, their role in the
organization and their job.
3. Identify and describe work-groups. A work-group is any group
of people who work together on a task, whether formally
constituted or not.
15. 15
CUSTOM model
4. Identify and describe task–object pairs. These are the tasks that
must be performed, coupled with the objects that are used to
perform them.
5. Identify stakeholder needs. Stages 2–4 are described in terms of
both the current system and the proposed system. Stakeholder
needs are identified by considering the differences between the
two.
6. Consolidate and check stakeholder requirements. Here the
stakeholder needs list is checked against the criteria determined
at earlier stages.
16. 16
OSTA model
OSTA is an alternative socio-technical approach, which attempts to
describe what happens when a technical system is introduced into
an organizational work environment. Like CUSTOM, OSTA
specifies both social and technical aspects of the system. However,
whereas in CUSTOM these aspects are framed in terms of
stakeholder perspectives, in OSTA they are captured through a
focus on tasks.
OSTA has eight main stages:
•The primary task which the technology must support is identified
in terms of users’ goals.
•Task inputs to the system are identified.
17. 17
OSTA model
3. The external environment into which the system will be
introduced is described, including physical, economic and
political aspects.
4. The transformation processes within the system are described in
terms of actions performed on or with objects.
5. The social system is analyzed, considering existing work-groups
and relationships within and external to the organization.
6. The technical system is described in terms of its configuration
and integration with other systems.
18. 18
OSTA model
7. Performance satisfaction criteria are established, indicating the
social and technical requirements of the system.
8. The new technical system is specified.
OSTA uses notations familiar to designers, such as data flow
diagrams and textual descriptions.
19. 19
Soft System Methodology
The socio-technical models we have looked at focus on identifying
requirements from both human and technical perspectives, but they
assume a technological solution is being proposed. Soft systems
methodology (SSM) arises from the same tradition but takes a view
of the organization as a system of which technology and people are
components. There is no assumption of a particular solution: the
emphasis is rather on understanding the situation fully.
SSM was developed by Checkland to help designers reach an
understanding of the context of technological developments and the
influences and concerns that exist within the system under
consideration.
22. A man went to a barbershop to have his hair cut and his beard trimmed. As the barber began to work, they
began to have a good conversation. They talked about so many things and various subjects.
When they eventually touched on the subject of God, the barber said: "I don't believe that God exists."
"Why do you say that?" asked the customer. "Well, you just have to go out in the street to realize that God
doesn't exist.
Tell me, if God exists, would there be so many sick people? Would there be abandoned children?
22
23. If God existed, there would be neither suffering nor pain.
I can't imagine a loving God who would allow all of these things."
The customer thought for a moment, but didn't respond because he didn't want to start an
argument.
The barber finished his job and the customer left the shop.
23
24. Just after he left the barbershop, he saw a man in the street with long, stringy, dirty hair and an
untrimmed beard.
He looked dirty and unkempt.
The customer turned back and entered the barber shop again and he said to the barber:
"You know what? Barbers do not exist."
"How can you say that?" asked the surprised barber. 24
25. "No!" the customer exclaimed.
"Barbers don't exist because if they did, there would be no people with dirty long hair and untrimmed
beards, like that man outside."
"Ah, but barbers DO exist! That's what happens when people do not come to me."
"Exactly!" affirmed the customer.
"That's the point! God, too, DOES exist!
That's what happens when people do not go to Him and don't look to Him for help. 25
