csci928 software engineering requirements & specifications modeling system interactions tri a....
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CSCI928Software Engineering Requirements &
Specifications
Modeling System Interactions
Tri A. Kurniawan, M.Eng.
Ph.D Candidate
CSCI928 Modeling System Interactions 2/23
Agenda
▶ Introduction
▶ Early-phase of Requirements Engineering
▶ Late-phase of Requirements Engineering
▶ Deriving Use Case from Organizational Modeling
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Goal and Phases
▶ Goal capturing system functional requirements represented in a certain software modeling language (e.g. UML : UC diagram, sequence diagram, statechart diagram, etc.)
▶ Requirement engineering phases : Early-phase : problem domain understanding
(organizational modeling e.g. i*, business process modeling e.g. BPMN) less attention
Late-phase : produce a deliverable requirements document including software modeling e.g. UML
CSCI928 Modeling System Interactions 4/23
Agenda
▶ Introduction
▶ Early-phase of Requirements Engineering
▶ Late-phase of Requirements Engineering
▶ Deriving Use Case from Organizational Modeling
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i* : Strategic Dependency Model - SD
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
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i* : Rationale Dependency Model - RD
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
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BPMN Process Modeling
▶ R1, R2, R3, R4, R5 for Sales Staff, Workshop Staff, Sales Manager, Workshop Manager, and General Manager respectively
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Process Abstraction
▶ Process for reducing the undesired details from the base model in order to retain only information relevant for a particular task
▶ Example : abstraction for R3 – Sales Manager
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Agenda
▶ Introduction
▶ Early-phase of Requirements Engineering
▶ Late-phase of Requirements Engineering
▶ Deriving Use Case from Organizational Modeling
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UML Modeling
▶ Unified Modeling Language (UML) is a standardized general-purpose modeling language in the field of software engineering
▶ Most useful interaction diagrams : use case diagram, sequence diagram
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Use Case Diagram▶ The main purpose to help development teams
visualize the functional requirements of a system, including the relationship of "actors" to essential processes, as well as the relationships among different use cases
▶ Elements : actor, use case, relationship▶ Actor : anything that needs to interact with the system
(person, role, another system)▶ Use case : a sequence of related actions performed by
an actor and the system via a dialogue▶ Relationships : actor (generalization), use case
(generalization, extend, include)
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UC Diagram Example
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UC Relationships
Actor Relationship Use Case Relationships
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Use Case Scenario
▶ Describe what the system must provide to the actor when the use case is executed
▶ Typical contents : Name and brief description Pre-condition and post-condition Normal flow Alternate flow Special requirements
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Sequence Diagram
▶ It shows how processes operate with one another and in what order
▶ Sequence diagrams show step-by-step what’s involved in a use case
▶ You may need several sequence diagrams to describe a single use case each sequence diagram describes one possible scenario for the use case
▶ Elements : object, stimulus (message)
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Sequence Diagram Example
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Agenda
▶ Introduction
▶ Early-phase of Requirements Engineering
▶ Late-phase of Requirements Engineering
▶ Deriving Use Case from Organizational Modeling
CSCI928 Modeling System Interactions 18/23
Steps
Goal-Oriented Analysis
1. Discovering actors2. Discovering use case for the actors
3. Discovering and describing
scenarios of use case
Strategic Dependency (SD) models developed
through i* framework
Strategic Rationale (SR) models
developed through i* framework
Use case diagrams and textual
description of scenarios
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
CSCI928 Modeling System Interactions 19/23
Guidelines▶ Step 1:
Every actor in i* UC actor IS-A actor in i* UC actor generalization Actor in i* UC external actor
▶ Step 2: All of actor’s (dependee) dependencies (goals, tasks,
softgoal, resources) relating use case▶ Step 3:
Analyze each actor and its relationships in the SR model to extract information that can lead to the description of the UC scenario for the actor
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Example : SD
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
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Example : SR
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
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Example : Result
[Meeting scheduler : Victor F. A. S. and Jaelson F. B. C.]
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Exercise
[Meeting scheduler : Eric S.K.Y.]