Application Development and Integration life cycle

1. Waterfall Lifecycle

  

      This model supports large and complex projects in which the requirements are well defined.   It adopts sequential approach from requirements analysis through design, construction, testing and application deployment.

 

2. V Lifecycle

 

    适合对系统可靠性要求比较高的项目。强调测试。

    This model supports new product development or large enhancement projects when the size and complexity of the system is large enough to have a multilayered design.  Adopt this model when the requirements are well understood, complete, and stable and the technology & architecture of the solution is clear and visible.

       SOW(UAT plan)---Requirement(System Test plan)---Architecture Design(Integration Test plan)---Low Level Design(Unit Test Plan)----Construct(V model bottom) ---Unit Test ---Integration Test ---System Test ---UAT

 

2.1 Feature

 Concurrent Phases or Activities

 Mandatory unit testing
 Easy to plan 
 Emphasizes and encourages Verification and Validation at all phases

 

 

 

2.2 Disadvantage

 Does not handle iterations

 Changes are expansive

 More documentation and mandatory sign-off to move out  of the phase

 Like waterfall model, Product is not visible until the end

 

3. Staged Lifecycle

 

  架构已经定义好，允许分阶段的Low Level Design 和实现。

  In this model, certain intermediate work products (incremental deliveries) will be delivered to the client before final delivery of the entire application.

  It supports product development or large enhancement projects when the requirements are not well understood and skeptic on stability of requirements.

  The Staged Lifecycle is best suitable for the development of new products or for executing large enhancements.

   Cycle: Low level Design --- Build --- IT,ST,REL,AT

3.1 Feature

when the requirements not well understood, not complete or not stable.

when there is a need for continuous deliveries from customer side.

when allow incremental design and implementation in a number of stages.

allow for specification changes in the subsequent release

 

3.2 Disadvantage

need careful planning

extra overhead on multiple release

determining stage dependencies is difficult

 

 

4. Iterative Lifecycle

 This model supports large and complex projects with the following characteristics:

 Where continuous quality check & high degree of requirements management is needed through out the project.   

Where the requirements will change considerably and the environment is not stable.

Where it is not possible to specify the requirements in enough details upfront. Where delivering on time is essential, irrespective of the functionality.

 

cycle: Envisioning（构思） --- Design ---Build --- Test --- Release & Deployment

          上面cycle中每个阶段中分多次迭代。

 

 

5. Rapid Applicaton Development Lifecycle