UP Development - 2.Elaboration

Build the core architecture, resolve the high-risk elements, define most requirements, and estimate overall schedule and resources
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- Elaboration is the initial series of iterations during which : the follwing content

• The majority of requirements are discovered and stabilized
  • 70 ~ 80 % 의 requirements 는 수용되어야 한다.
  • wirte most of the Use Cases and other requirements in detail
• The marjor Risk are mitigated or retired. ( 기술 / 비지니스 관점에서 대다수의 위험성은 해결되어야 함 )
• The core Architectural elements are implemented and proven. ( System 의 중요한 architectural 는 어느 정도 구현되고 안정되어 있어야 한다 )

- Elaboration Phase

• Elaboration consists of between two and four iterations
  • each iteration is recommended to between two and six weeks, unless the term size is massive
• Each iteration is timeboxed, meaning its end date is fixed
• At the end of each iteration, stable and tested Production-Quality portions of the final system must be released
  ( 각각 iteration 마지막 부분에서, Final system 의 안정적이고 검증된 Production-Quality 부분은 반드시 해결되야 한다. )

- What is Architecturally Singificant in Elaboratoin?

• Employing Wide and Shallow design and implementation.
  • Implementing simplified and End to End scenarios that force design, implementation, and test across major components.
• Integrating existing componets

- Planning the Next Iteration

• Organize requirements and iterations by Risk, Coverage, and Criticality
• Risk
  • Includes Both technical complexity and other factors, such as uncertainty of effort or usablity
• Coverage
  • Implies that all major parts of the system are at least touched on in early iterations
• Criticality
  • Refers to functions of high business value

==>  3가지에 Weight 를 부여하여 높은 순서대로 먼저 수행한다.

- Artifacts that May Start in Elaboration

• Domain Model : This is a visualization of the domain concepts; it is similar to a static information model of the domain entities ( static / dynamic model )
• Design Model : This is the set of diagrams that describe the logical design, This includes software class diagram, object interaction diagram, packgae diagrams, and so forth

Drawing System Sequence Diagrams

- Objectives

• Identify system events and system operations.
• Create system sequence diagram for Use Cases.

- SSD ( System Sequence Diagrams )

• System behavior is a description of What a system does, without explaning How it does it
• System Sequence Diagram captures the system behavior, for a particular scenario of a Use Case, by illustrating the events that external actors generate to SuD, their order, and inter-system events
  • It allows us to treat the system as a BLack Box
• System Sequence Diagram emphasizes those events that Cross the system boundary from actors to systems
• System Sequence Diagram should be done for the main success scenario of the Use Case, and frequent or complex alternative scenarios

- System Events & System Operations

• System event is an external event generated by an external actor to a system —> Stimulus
• System operation is an operation of the system that executes in response to a system event —> Response
  • The set of all required system operations is determined by identifying the system evnets. The system events are derived from Use Case
    ( System 외부에서 Event 가 주어졌을때 해당 Event 에 대한 System 이 취한 동작 )

• System Sequence Diagram shows system events for a scenario of a Use Case, therefore it is generated from inspection of a Use Case

- Naming System Events / Operations

• System events and theri associated events should be Expressed at the (highest) level of Intent rather than in terms of physical input medium or interface widget
• Usually start with a “Verb” like add, enter, make …

- Showing Use Case Text

• The text provides the details and context
  the diagram visually summarizes the interaction

- Recording System Operations & Class Icon

• UML class icon provides a compartment to record operations for a type

- How To Make System Sequence Diagram

1. Draw a line representing the system as a black box
2. Identify each actor that directly operates on the system
   Draw a line for each such actor
3. From the Use Case main success scenario text,
   Identify the system ( External ) events that each actor generates. illustrate them on the diagram
4. Optionally, include the Use Case text to the left of the diagram