A Restricted Natural Language Based Use Case Modeling Methodology for Real-Time Systems

Time-related properties are a critical type of extrafunctionalrequirements for designing real-time systems. Modeling and validating time-related properties at therequirements specification and analysis phases is important forthe successful development of real-time systems in terms of cost, quality and productivity. In the literature and practice, timinganalyses (e.g., Worst Case Execution Time) are often performedto ensure that the design of a real-time system fully conforms toits time-related constraints. However, such analyses are mostlyperformed at the design and implementation stages, but not atthe requirements level. This paper presents a restricted, naturallanguage based, use case modeling methodology (named asRUCM4RT) to specify functional requirements of real-timesystems as use case models, along with associated time-relatedconstraints. RUCM4RT was proposed based on the UMLprofile for Modeling and Analysis of Real-Time and EmbeddedSystems (MARTE). In addition, in this paper, we also propose ametamodel-based formalization mechanism named asUCMeta4RT to automatically formalize use case models. Wehave conducted two real-world case studies to evaluate oursolution and 40 use cases were modeled, among which 27 realtimeuse cases, 118 time-related constraints and 47 other extrafunctional(also commonly called non-functional) constraintswere specified. Results show that RUCM4RT was able to handleall the real-time related elements (e.g., time-related constraints)of the use case models.