System Analysis and Design - Second Assignment

1. Simple questions

1. Briefly describe the advantages and disadvantages of waterfall model, incremental model, and spiral model (including prototype method).

• waterfall model

  • advantage:
    
    1. Checkpoints by phase are provided for the project.
    2. After the current stage is completed, just focus on the subsequent stages
    3. Can be applied in iterative models
  • shortcoming:
    
    1. The division of each stage is fixed, and there will be a large number of documents between stages, which increases the workload
    2. With a linear development model, users can only wait until the final stage to see the results, increasing the development risk.
    3. Not adapting to changes in user needs

• Incremental model

  • advantage:
    
    1. By modularizing the software system to be developed, software products can be submitted in batches, so that users can keep abreast of the progress of software projects.
    2. Incremental investment is allowed, i.e. only one or two incremental investments can be made at the beginning of the project
    3. The development sequence is flexible. Developers can prioritize the implementation order of components, and complete core components with stable requirements first. When the priority of components changes, the implementation order can also be adjusted in time
  • shortcoming:
    
    1. When the user's change requirements are not planned, the initial increment will cause instability in future increments
    2. The increments generated in the process may need to be re-released and re-developed, which increases the difficulty of the work
    3. Progress and configuration can be complex beyond progress.
• Spiral model
  
  • advantage:
    
    1. Flexible in design, changes can be made at various stages of the project
    2. Each large system consists of small segments, making cost control calculations easier
    3. The customer basically participates in each stage of development, which can ensure the stability of the project
    4. Customers agree with this model and think that they can communicate well with developers
  • shortcoming:
    
    1. The construction period is long, and the software development technology is relatively fast. It often occurs that when the development is completed, there is a large gap between the software level and the current level, which cannot meet customer needs.
    2. This approach is sometimes inefficient when requirements are clear.

2. Briefly describe the three characteristics of UP, which content reflects user-driven development, and which content reflects risk-driven development?

• Three characteristics of up:
  
  1. Software development is an iterative process
  2. Software Development is Driven by Use Cases
  3. Software development is centered on Architectural Design.
     
     • Software development is an iterative process and risk-driven development, while software development is use case-driven and user-driven development centered on architecture design.

3. What are the criteria for dividing the four stages of UP? What are the key milestones?

• The four stages of up:
  
  1. Initial Phase : The goal of the initial phase is to build a business case for the system and define the boundaries of the project. The initial phase ends with the first major milestone: the Lifecycle Objective milestone . Life cycle goals and milestones evaluate the basic viability of a project.
  2. Elaboration Phase : The goal of the Elaboration Phase is to analyze the problem area, establish a sound architectural foundation, prepare a project plan, and eliminate the highest risk elements of the project. The second important milestone at the end of the refinement phase: the Lifecycle Architecture milestone . Lifecycle structure milestones establish a management baseline for the structure of the system and enable the project team to measure during the build phase.
  3. Construction phase : In the construction phase, all remaining components and application functions are developed and integrated into a product, and all functions are tested in detail. The build phase ends with the third important milestone: the Initial Operational milestone . The initial functional milestone determines whether the product can be deployed in a test environment. At this point, it is necessary to determine whether the software, the environment, and the user can start the operation of the system.
  4. Delivery Phase : The delivery phase focuses on ensuring that the software is available to end users. At the end of the delivery phase is the fourth milestone: the Product Release milestone . At this point, it's time to determine if the goal is achieved and if another development cycle should begin. In some cases this milestone may coincide with the end of the initial phase of the next cycle.

4. In IT project management, among the three elements of "duration, quality, scope/content", under the fixed conditions of the contract, why is it said that "scope/content" is easy for the project team to control.

1. In an IT project, the construction period is negotiated by the client and the team in the contract and cannot be changed at will.
2. The quality is set by the customer to the team in the contract, and it cannot be changed at will.
3. In order to complete the project better, under suitable conditions, the team should appropriately change the scope/content to better adapt to the change in requirements, which is easy for the team to control.

5. Why do you say that UP provides a basis for companies to produce software products at a fixed rhythm and release software products in a fixed cycle?

• RUP adopts an iterative development model, and each stage in RUP can be further decomposed into iterations. An iteration is a complete development cycle that produces an executable version of the product, a subset of the final product, that evolves incrementally, from one iterative process to another to become the final system.

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