Requirements Validation with Enactable Models of State-based Use Cases Chin-Yi Tsai

2 Outline Introduction Dependencies in Use Case Specification-a case study Experiences from the Study Conclusions

3 Introduction UML use case for requirements specification.  Authoring guideline for use case Different writing styles???  common writing scheme is important This paper  To enhance use cases for the specification of interdependencies between stakeholder requirements To enhance the explicit consideration of dependencies amongst use case events as a mechanism for validation. The traditional way of specifying interactions in systems is the use of a process algebra Constructing state-based business process models using the process modelling language RolEnact Producing enactable business process models depicting role interactions, this approach was found to bridge the communication gap between process modellers and business stakeholders, hence enhancing shared understanding.

4 Dependencies in Use Case Specification-a case study Use case description of the client-server connection process 1.Client looks-up the Domain Naming Service 2.Client creates a connection Socket 3.Client connects to server 4.Server requests login data 5.Client sends login data 6.Server authenticates login data Most authors of use case specification seldom consider dependencies  The presumption normally is that events follow a time-order dependency However, most control system are complex

5 Dependencies in Use Case Specification-a case study (Cont’d) Augmentation of use case events with pre and post conditions to explicitly determine whether the sequence of events in the use case is correct, and provide a mechanism for revising to correct any flaws Dependencies  Among events  Across multiple use case

6 Dependencies among Events

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8 A client’s network setup must be initialized by the Scheduler to ensure that any previous network activity by client does not hamper connectivity to different server application.

9 Dependencies Across Multiple Use Cases Association between actors in a use case or across use cases are not allowed

10 Conclusions Highlighting the implication for the lack of explicit consideration of dependencies in use case specification.  Dependencies among events  Dependencies across multiple use cases Investigation of dependencies issues provides greater comprehension of both the problem domain and the behavior  Vital to requirements validation Enactable approach that provides rigour in specification, and enhances communication during enaction.