The document discusses the design model and architectural design process. The design model has two dimensions - the process dimension outlines the evolution of the design tasks, while the abstraction dimension represents the level of detail. The design model elements include data design, architectural design, interface design, component design, and deployment design. The architectural design process involves representing the system context, defining archetypes, refining the architecture into components, and describing system instantiations.

1. THE DESIGN MODEL

2. DIMENSIONS OF THE DESIGN
MODEL
Process Dimension (Progression)
Abstraction
Dimension
Data/Class
Elements
Interface
Elements
Architectural
Elements
Component-level
Elements
Deployment-level
Elements
Analysis model
Design model

3. INTRODUCTION
 The design model can be viewed in two different
dimensions
 (Horizontally) The process dimension indicates the
evolution of the parts of the design model as each
design task is executed
 (Vertically) The abstraction dimension represents the
level of detail as each element of the analysis model is
transformed into the design model and then iteratively
refined

4. INTRODUCTION
 The design model has the following layered elements
 Data/class design
 Architectural design
 Interface design
 Component-level design
 Deployment-level design

5. DATA/CLASS DESIGN
 Data/class design creates a model of data and
objects that is represented at a high level of
abstraction
 This data model is refined into progressively
more implementation-specific representations
that can be processed by computer based
systems

6. ARCHITECTURAL DESIGN
 Architectural design for the software is equivalent to
the ‘floor plan’ of a house
 Depicts the overall layout of the software
 Derived from three sources-
 Information about the application domain
 Specific requirements elements
 Architectural styles and patterns

7. INTERFACE DESIGN
 Tells how information flows into and out of the
system and how it is communicated among the
components defined as part of the architecture
 Includes the user interface, external interfaces, and
internal interfaces

8. COMPONENT-LEVEL DESIGN
 Describes the internal detail of each software
component by way of data structure definitions,
algorithms, and interface specifications

9. DEPLOYMENT-LEVEL DESIGN
 Indicates how software functionality and
subsystems will be allocated within the physical
computing environment that will support the
software

10. EVOCATION

11. ARCHITECTURAL
DESIGN

12. SOFTWARE ARCHITECTURE
 The software architecture of a program or computing
system is the overall structure of the system which
comprise
 The software components
 The externally visible properties of those components
 The relationships among the components
 Constitutes a relatively small, intellectually graspable
model of how the system is structured and how its
components work together.

13. ARCHITECTURAL DESIGN
STEPS
1) Represent the system in context
2) Define archetypes
3) Refine the architecture into components
4) Describe instantiations of the system

14. 1. REPRESENT THE SYSTEM IN
CONTEXT
 Uses an architectural context diagram (ACD) that
models the manner in which software interacts with
entities external to its boundaries

15. 1. REPRESENT THE SYSTEM IN
CONTEXT
 An ACD identifies systems that interoperate with the target system
(system for which architectural design is to be developed.
 Super-ordinate systems
 Use target system as part of some higher level processing
scheme
 Sub-ordinate systems
 Used by target system and provide necessary data or
processing details
 Peer-level systems
 Interact on a peer-to-peer basis with target system to
produce or consume data
 Actors
 People or devices that interact with target system to produce
or consume data

16. 1. REPRESENT THE SYSTEM IN
CONTEXT
Target system
I/F I/F
I/F I/F I/F
Actors
Peers
"Super"ordinate systems
"Sub"ordinate systems
Used by
Produces or
consumes
Produces or
consumes
Depends on
Uses

17. 2. DEFINE ARCHETYPES
 An archetype is a class or pattern that represents a
core abstraction that is critical to the design of an
architecture for the target system
 In general, a small set of archetypes is required to
design even relatively complex systems.
 The target system architecture is composed of these
archetypes, which represent stable elements of the
architecture but may be instantiated in different ways
based on the behavior of the system
 The archetypes and their relationships can be
illustrated using UML diagrams

18. EXAMPLES
 Archetypes in Software Example Architecture –
 Node
 Detector/Sensor
 Indicator
 Controller
Figure 10.7 UML relationships for SafeHome security function archetypes
(adapted from [BOS00])
Controller
Node
communicates with
Detector Indicator

19. 3. REFINE THE ARCHITECTURE
INTO COMPONENTS
 Based on the archetypes, the architectural designer refine the
software architecture into components to illustrate the overall
structure and architectural style of the system
 These components are derived from various sources
 The application domain provides application components,
which represent the entities in the real world
 The infrastructure domain provides design components (i.e.,
design classes) that enable application components but have no
business connection
 The interfaces in the ACD imply one or more specialized
components that process the data that flow across the interface
 An UML class diagram can represent the classes of the refined
architecture and their relationships

20. COMPONENT STRUCTURE
SafeHome
Executive
Ext ernal
Communicat ion
Management
GUI Internet
Interface
Function
select ion
Security Surveillance Home
management
Control
panel
processing
detector
management
alarm
processing

21. 4. DESCRIBE INSTANTIATIONS OF
THE SYSTEM
 An actual instantiation of the architecture is
developed by applying it to a specific problem
 This demonstrates that the architectural structure,
style and components are appropriate
 An UML component diagram can be used to
represent this instantiation

22. INSTANTIATIONS OF THE SYSTEM
sensor
sensor
sensor
sensor
sensor
sensor
sensor
sensor
Ext ernal
Communicat ion
Management
G
UI Internet
Interface
Security
Cont rol
panel
processing
det ect or
m anagem ent
alarm
processing
Key pad
processing
CP display
funct ions
scheduler
sensor
sensor
sensor
sensor
phone
com m unicat ion
alarm
SafeHome
E
xecutive

23. MIND MAP

24. SUMMARY
• The Design Model
– Dimensions
• Process Dimension
• Abstraction Dimension
– Data design elements
• Data architecting
– Architectural design elements
– Interface design elements
• User Interfaces
• External Interfaces
• Internal Interfaces
– Component-level design elements
– Deployment-level design elements

25. • Architectural Design
– Representing the System in Context
– Defining Archetypes
– Refining the Architecture into Components
– Describing Instantiations of the System