INCEPTION,Analysis and Design Overview

Part 3 - INCEPTION
2
Objectives
What we will learn:
 Define the inception step.
3
Purposes of Inception
The intent of inception is to:
 Establish some initial common vision for the
objectives of the project,
 Determine if it is feasible, and
 Decide if it is worth some serious
investigation in elaboration.
4
Example Questions in Inception
For example, you need to ask questions such
are explored:
 What is the vision and business case for this
project?
 Feasible?
 Buy and/or build?
 Rough estimate of cost: Is it $10K-100K or
in the millions?
 Should we proceed or stop?
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What Artifacts (WP) May Start in Inception?
Describes the functional requirements, and related
non-functional requirements.
Use-Case Model
Comment
Artifact
Describes the high-level goals and constraints, the
business case, and provides an executive summary.
Vision and
Business Case
Prototypes and To clarify the vision, and validate technical ideas.
proof-of-concepts
Describes the business, technical, resource, schedule,
people, education, and other resources, risks control
Project
management Plan
Describes risks (the business, technical, resource,
schedule), and ideas for their mitigation or response.
Risk List & Risk
Management Plan
Glossary Key domain terminology
6
Requirements Artifacts
Vision
Supplementary
Specification
Software
Architecture Doc .
Glossary
Domain
M o d e l
Requirements
Project
Management
Business
Modeling
Design
Partial a rtifa cts ,
refined in each
iteration .
T e s t
T e s t
P l a n
Software
D e v . P l a n
Design Model
*
*
U s e -C a s e
M o d e l
Environment
Development
C a s e
7
You Know You Didn't Understand Inception When...
 It is more than "a few" weeks long for most projects.
 There is an attempt to define most of the requirements.
 Estimates or plans are expected to be reliable.
 You define the architecture (this should be done iteratively
in elaboration).
 You believe that the proper sequence of work should be: 1)
define the requirements; 2) design the architecture; 3)
implement.
 There is no Business Case or Vision artifact.
 All the use cases were written in detail.
 None of the use cases were written in detail; rather,
1020% should be written in detail to obtain some realistic
insight into the scope of the problem.

Analysis and Design Overview
2
Objectives: Analysis and Design Overview
 Review the key Analysis and Design terms
and concepts
 Introduce the Analysis and Design process,
including roles, artifacts and workflow
 Explain the difference between Analysis
and Design
3
Analysis and Design in Context
The purposes of Analysis and Design
are to:
 Transform the requirements into a
design of the system-to-be.
 Evolve a robust architecture for the
system.
 Adapt the design to match the
implementation environment,
designing it for performance.
The purposes of Analysis and Design
are to:
 Transform the requirements into a
design of the system-to-be.
 Evolve a robust architecture for the
system.
 Adapt the design to match the
implementation environment,
designing it for performance.
4
Supplementary
Specification
Use-Case Model
Design Model
Data Model
Architecture
Document
Analysis
and Design
Analysis and Design Overview
Glossary
5
Analysis Versus Design
 Focus on understanding
the solution
 Operations and attributes
 Performance
 Close to real code
 Object lifecycles
 Nonfunctional
requirements
 A large model
 Focus on understanding
the problem
 Idealized design
 Behavior
 System structure
 Functional requirements
 A small model
Analysis Design
6
Design Classes
Subsystems
Use Cases
Analysis and Design Are Not Top-Down or Bottom-Up
Analysis Classes
Bottom
Up
Top
Down
(Define a
middle level)
Analysis and Design
7
What Is Architecture?
 Software architecture encompasses a set of
significant decisions about the organization
of a software system.
 Selection of the structural elements and their
interfaces by which a system is composed
 Behavior as specified in collaborations among
those elements
 Composition of these structural and behavioral
elements into larger subsystems
 Architectural style that guides this organization
Grady Booch, Philippe Kruchten, Rich Reitman, Kurt Bittner; Rational
(derived from Mary Shaw)
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Architecture Constrains Design and Implementation
 Architecture involves a set of strategic
design decisions, rules or patterns that
constrain design and construction.
Architecture decisions are the most fundamental
decisions, and changing them will have significant effects.
Architecture
Design
Implementation
Code
9
Software Architecture: The “4+1 View” Model
Process View
Deployment View
Logical View
Use-Case View
Implementation View
End-user
Functionality
Programmers
Software management
Performance, scalability, throughput
System integrators
System topology, delivery,
installation, communication
System engineering
Analysts/Designers
Structure
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Analysis and Design Workflow
Analysis
Design
[Early Elaboration
Iteration]
[Inception Iteration
(Optional)]
Define a Candidate
Architecture
Perform
Architectural
Synthesis
Analyze Behavior
Refine the
Architecture
Design
Components
Design the
Database
(Optional)
11
Analysis and Design Activity Overview
Architect
Designer
12
Software Architect’s Responsibilities
Architect
Software
Architecture
Document
 The Software
Architect leads
and
coordinates
technical
activities and
artifacts.
Reference
Architecture
Analysis Model
Design Model
Implementation Model Deployment Model
13
Designer’s Responsibilities
Designer
Use-Case
Realization
Package Class/Subsystems
 The designer
must know usecase
modeling
techniques,
system
requirements,
and software
design
techniques.
14
Review: Analysis and Design Is Use-Case Driven
 Use cases defined for a system are the
basis for the entire development process.
 Benefits of use cases:
 Concise, simple, and understandable by a wide range
of stakeholders.
 Help synchronize the content of different models.
Withdraw Money
Check Balance
Customer
15
What Is a Use-Case Realization?
Use Case Class Diagrams
Communication
Diagrams
Use-Case Model Design Model
Use Case Use-Case Realization
Sequence
Diagrams
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Analysis and Design in an Iterative Process
Iteration n Iteration n + 1
Use Case A
Scenarios 1 & 2
Use-Case
Realization A
Start of iteration
End of iteration
Use Case B
Scenario 1
Use-Case
Realization A
Use Case A
Scenario 3
Use-Case
Realization B
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Review: Analysis and Design Overview
 What is the purpose of the Analysis and
Design Discipline?
 What are the input and output artifacts?
 Name and briefly describe the 4+1 Views of
Architecture.
 What is the difference between Analysis
and Design?
 What is architecture?