The document describes a general design process model that involves identifying requirements, analyzing and building a problem model, postulating a design solution, validating the solution through iterations, revising the design solution through iterations, and comparing solutions. It then describes four design strategies: (1) decompositional methods that break down problems into subproblems, (2) compositional methods that identify entities, classify them into groups, and establish relationships, (3) design templates and reuse of past effective designs, and (4) incremental and evolutionary trial-and-error approaches.

1. Design Process Activity
Participants
The people who is going to perform the
action.
Input
Requirements and Specifications.
Action
It is represented by a verb..
Conditions and Constraints
In general they are discovered during the
development of the solution.
Output
Design Specifications
05
01
02 03
04

2. Design Process Model
A process model describes the activities involved in the design process and the
interrelationships between the activities.

3. A General Design Process Model
Identify Nature of
Requirements
Analyse & Build
Model of Problem
Postulate Design
Solution
Validate Solution (1) Validate Solution (n)
First Iteration

4. A General Design Process Model
Analyse & Build
Model of Problem
Postulate Design
Solution
Validate Solution (1) Validate Solution (n)
Revise Design
Solution (1)
Revise Design
Solution (n)
Second Iteration
Compare Solutions
Elaborate Solution

5. Design Strategies: Prescriptive Models
1
Decom
positionalM
ethods
Ittakes
a
top-dow
n
approach
to
the
design
process.Itstarts
w
ith
an
originaldescription
ofthe
problem
ora
m
odelofthe
originalproblem
.
This
originalproblem
is,then,decom
posed
into
a
num
berof
sub-problem
s.These
sub-problem
s
are
then
solved
separately.
2
Com
positionalM
ethods
Itstarts
the
building
ofa
m
odelidentifying
a
setofparticular
entities
orobjects
involved
in
the
problem
.Afterthat
they
are
classified
and
grouped.Foreach
group,the
relationships
betw
een
the
entities
are
identified
so
thatlinks
betw
een
entities
are
established.Such
groups
form
the
com
ponents
of
the
m
odel.
3
Design
Tem
plate
and
Design
Reuse
Fora
certain
type
ofproblem
in
a
certain
application
dom
ain,
there
m
ay
be
a
greatdealofsim
ilarities
in
the
designs
thatare
proved
to
be
effective.Ifsuch
sim
ilarities
can
be
abstracted
into
a
tem
plate
ofdesign,then
once
a
problem
is
identified
to
be
an
instance
ofsuch
a
class
ofproblem
s,the
design
tem
plate
can
be
instantiated.
4
Increm
entaland
Evolutionary
Trial-and-erroris
perhaps
the
m
ostbasic
approach
to
alldesigns.Itinvolves
the
creation
ofa
design
and
the
evaluation
ofthe
design
againstthe
requirem
ents
and
constraints.Ifsom
e
requirem
ents
and/orconstraints
are
notsatisfied,the
design
is
m
odified
and
a
new
design,even
new
designs,created.