What is a Life Cycle?
•
•
•
Life Cycle: Describes
how a product goes
from conception to
retirement
Life Cycle Model
(LCM): Generally a set
of phases (with
exit/entry milestones)
that describe how a
product goes from
conception to
retirement.
Each phase of a Life
Cycle is generally
characterized by a set
of:




Activities
Milestones
Artifacts
Reviews
•
Examples:
 Classic Waterfall
LCM (1970)
 Improved Waterfall
LCM (1981)
 “V” LCM (1991)
 Spiral Deployment
LCM (1981)
 Iterative
Development LCM
(1999)
 Block/Incremental
Development LCM
Dr. John MacCarthy
UMBC CMSC 615
3
What is a Development Life
Cycle/Process?
 Generally it is the portion of the life cycle
dealing with development.
 Generally a (Software) Development Life
Cycle/Process includes:
 Requirements
 Design
 Implementation/Coding/Unit Testing
 Integration Testing/Verification
 Notice that it generally excludes:
 Manufacturing
© Gert Jervan
 Deployment
 Operations
 Retirement
4
Life Cycle Model with Decision
Gates
Decision Gates
Concept
Concept
Stage
Stage
Feasibility
Stage
Development
Development
Stage
Stage
Production
Production
Stage
Stage
Utilization
Utilization
Stage
Stage
Support
Support
Stage
Stage
Retirement
Retirement
Stage
Stage
Copyright – Harold (Bud) Lawson
5
Classic Waterfall Model
(Royce 1970)
6
Technical Reviews and Audits
•
Alternative Systems/Concept
Review (ASR/ACR)


•
System Requirements Review (SRR)






•
•
Approve/Kick off start of project
PMP/SEMP/TEMP
Customer Requirements
Top-Level Functional Architecture
Top-Level Conceptual Design
Draft Specs
Approve System Spec
Approve Conceptual Design
End of Concept/Architecture
Phase
Software Specification Review
(SSR): See PDR
Preliminary Design Review (PDR)



Approve Performance Item Spec
Approve Preliminary Design
End of Requirements Phase
Critical Design Review (CDR)


•

•


[1st unit acceptance]
Verifies that PI Spec meets
Customer Requirements
Verifies that DI Spec meets PI
Spec
End of Testing
Production Readiness/Approval
Review (PRR/PAR)

•
Approve start of [integration]
testing
End of Development Phase
Functional Configuration Audit/
System Verification Review
(FCA/SVR)


•
Approve Final Design (DI Specs)
End of Design Phase
Test Readiness Review (TRR)

System Design/ Definition/
Functional Review (SDR/SFR)



•
Select preferred system concept
Approve/Kick off acquisition
•
Approve start of unit production
Physical Configuration Audit (PCA)


Formalizes (corrected) Product
Baseline for Production
Follows PRR/PAR
7
Improved Waterfall Model
(Boehm 1981)
© Gert Jervan
(Sage, Rouse 1999)
8
Concurrent Waterfall
Requirements Analysis
SRR/SDR/SFR
Specifications Development
PDR
CDR
Design
Implementation
Testing
TRR
FCA/SVR
(Manufacturing,) Deployment,
Operations, & Retirement
9
Modified Waterfall Life Cycle
Models
© Gert Jervan




Waterfall with Concurrent Design/Development
Evolutionary Prototyping
Staged Delivery/Design to Schedule
Evolutionary Delivery
10
“V” Model from SEF (Ould, 1990)
Separating specification and design
11
V Model
Systems Engineering Guidebook for ITS
12
© Gert Jervan
The System Life Cycle
13
© Gert Jervan
Spiral Model (Boehm, 1981)
14
Iterative Life Cycle Model
© Gert Jervan
(Kruchten 1999)
15
System Life Cycle processes
Example stages
Stage
Description
Concept
Analyze needs, identify concepts and
develop solutions
Engineer a product that is a producible item
Development
Develop a service for a user
Manufacture the item(s)
Production
Establish the service including processes,
documentation, facilities, and training
Utilization
Operate and use the item(s)
© Gert Jervan
Provide the service
Support
Maintain and support the item(s)
Retirement
Retire, dispose and archive
Copyright – Harold (Bud) Lawson
16
Some Potential
Life Cycle Models
Compare to the
Generic:
-Definition
-Production
-Utilization
17
Life Cycle Roles and
Responsibilities
LIFE CYCLE STAGES
CONCEPTIONDEVELOPMENT PRODUCTION UTILIZATION
Needs,
CONCEIVERS Concepts,
Feasibility
ACTORS
DEVELOPERS
PRODUCERS
Engineering,
Solutions,
Practicability
Fabrication,
Assembly,
Verification
USERS
SUPPORTERS
Cohesion
Integrity
Feasibility
SUPPORT
RETIREMENT
Consistency
Practicability
Viability
Operation,
Usage,
Validation
Installation,
Maintenance,
Logistics
Integrated Project Team
Organizational
roles
Contribute to
Reuse,
Archiving,
Destruction
RETIRERS
Through-life Management
Copyright – Harold (Bud) Lawson
18
Life Cycle Models and Processes
 Managing life cycle models
 A small number of generic life cycle models are required
for running the business of the organization/enterprise
 Life Cycle Models are systems and must be Life Cycle
Managed via the Life Cycle Management Process
 Process management
 Also managed according to the Life Cycle Management
Process
 Tailoring applied to provide processes relevant for various
the types of systems
• A life cycle model is defined in terms of stages and the
contributions they make.
• Individual life cycle stages that influence the fulfillment of an
agreement to supply a system product or service are
described.
© Gert Jervan
• Modified or new system life cycle processes are defined.
19
Life Cycle Management Process
 This process provides life cycle policies, processes,
models, and procedures that are consistent with the
organization's objectives, that are defined, adapted,
improved and maintained to support individual project
needs within the context of the organization, and that
are capable of being applied using effective, proven
methods and tools.
 Outcomes
 As a result of the successful implementation of the Life
Cycle Model Management Process:
• a) Policies and procedures for the management and
deployment of life cycle models and processes are provided.
• b) Responsibility, accountability, and authority for life cycle
management are defined.
© Gert Jervan
• c) Life cycle processes, models, and procedures for use by the
organization are defined, maintained, and improved.
• d) Prioritized process, model, and procedure improvements are
implemented.
20