Modeling and analysis of real-time software systems using UML

Real-Time Systems (RTS) should not only function correctly but should also satisfy time constraints. RTS include embedded systems, which are used nowadays in a variety of applications. These are, for instance, house appliances, automotive, aeronautic/aerospace, and health monitoring systems, to mention just a few. The design of such systems is complex and challenging. In order to cope with the complexity of RTS, there is shift in their development to follow a model-driven approach, such as the Model Driven Architecture (MDA), which relies on using models of high level of abstraction. The Unified Modeling Language (UML) is the Object Management Group (OMG) standard modeling language to support MDA. UML is appropriate for software systems because it allows for a multi-view modeling approach through its multitude of diagrams covering the structure, the behavior and the deployment architecture. Moreover, UML is also used in the domain of real-time software systems. This is achieved through its profiles, including, the OMG standard profile for Schedulability, Performance and Time (UML/SPT) or the upcoming standard UML Profile for Modeling and Analysis of Real-Time and Embedded Systems (MARTE). However, UML modeling faces some challenging issues such as model consistency. This issue becomes worse in the context of real-time software systems because additional aspects should be taken into consideration, including time, concurrency and schedulability. In this thesis, we address several issues related to modeling and validation of RTS with UML. We focus in particular on the consistency of UML/SPT models. We adopt an incremental approach to check the consistency of these models by distinguishing the syntactic and semantic levels. The latter is further decomposed into behavioral, concurrency-related and time consistency. Our contributions in this thesis are fourfold. First, we leverage the extensibility mechanisms of UML to propose an extension to UML/SPT. This extension enables the modeling of multicast communications, which is required for the description of the behavior of certain real-time protocols. Second, we propose a formalization of the concurrency modeling capability in UML/SPT using timed automata. This formal semantics allows for applying well-established model checking techniques to check concurrency related consistency in UML/SPT models. Third, we propose an MDA-compliant approach to enable schedulability analysis of UML/SPT models. We present a proof of concept for this approach through a prototype implementation using the Atlas Transformation Language (ATL) and XML-based technologies. Finally, we use the schedulability analysis applied to UML/SPT models in order to check the time consistency of a system design modeled by means of a set of state machines with respect to time constraints modeled using a set of sequence diagrams annotated with UML/SPT time stereotypes. Keywords : Real-time systems, Model-driven Architecture, UML, UML/SPT, Model transformation, ATL, XML, XSLT, Consistency, Concurrency, Model Checking, Schedulability Analysis

A Practical Example for Model-Driven Web Requirements

The number of approaches for Web environments has grown very fast in the last years: HDM, OOHDM, and WSDM were among the first, and now a large number can be found in the literature. With the definition of MDA (Model- Driven Architecture) and the acceptance of MDE (Model-Driven Engineering) techniques in this environment, some groups are working in the use of metamodels and transformations to make their approaches more powerful. UWE (UMLBased Web Engineering) or OOWS (Object-Oriented Web Solutions) are only some examples. However, there are few real experiences with Web Engineering in the enterprise environment, and very few real applications of metamodels and MDE techniques. In this chapter the practical experience of a Web Engineering approach, NDT, in a big project developed in Andalusia is presented. Besides, it shows the usability of metamodels in real environments

Making formal verification amenable to real-time UML practitioners

TTool, a real-time UML toolkit, offers user-friendly interfaces to formal verification techniques such as reachability analysis, observer-based analysis and automatic generation of traceability matrices. Those techniques are surveyed in the paper

A Framework for Evaluating Model-Driven Self-adaptive Software Systems

In the last few years, Model Driven Development (MDD), Component-based Software Development (CBSD), and context-oriented software have become interesting alternatives for the design and construction of self-adaptive software systems. In general, the ultimate goal of these technologies is to be able to reduce development costs and effort, while improving the modularity, flexibility, adaptability, and reliability of software systems. An analysis of these technologies shows them all to include the principle of the separation of concerns, and their further integration is a key factor to obtaining high-quality and self-adaptable software systems. Each technology identifies different concerns and deals with them separately in order to specify the design of the self-adaptive applications, and, at the same time, support software with adaptability and context-awareness. This research studies the development methodologies that employ the principles of model-driven development in building self-adaptive software systems. To this aim, this article proposes an evaluation framework for analysing and evaluating the features of model-driven approaches and their ability to support software with self-adaptability and dependability in highly dynamic contextual environment. Such evaluation framework can facilitate the software developers on selecting a development methodology that suits their software requirements and reduces the development effort of building self-adaptive software systems. This study highlights the major drawbacks of the propped model-driven approaches in the related works, and emphasise on considering the volatile aspects of self-adaptive software in the analysis, design and implementation phases of the development methodologies. In addition, we argue that the development methodologies should leave the selection of modelling languages and modelling tools to the software developers.Comment: model-driven architecture, COP, AOP, component composition, self-adaptive application, context oriented software developmen

Towards a Tool-based Development Methodology for Pervasive Computing Applications

Despite much progress, developing a pervasive computing application remains a challenge because of a lack of conceptual frameworks and supporting tools. This challenge involves coping with heterogeneous devices, overcoming the intricacies of distributed systems technologies, working out an architecture for the application, encoding it in a program, writing specific code to test the application, and finally deploying it. This paper presents a design language and a tool suite covering the development life-cycle of a pervasive computing application. The design language allows to define a taxonomy of area-specific building-blocks, abstracting over their heterogeneity. This language also includes a layer to define the architecture of an application, following an architectural pattern commonly used in the pervasive computing domain. Our underlying methodology assigns roles to the stakeholders, providing separation of concerns. Our tool suite includes a compiler that takes design artifacts written in our language as input and generates a programming framework that supports the subsequent development stages, namely implementation, testing, and deployment. Our methodology has been applied on a wide spectrum of areas. Based on these experiments, we assess our approach through three criteria: expressiveness, usability, and productivity

A Modeling Approach based on UML/MARTE for GPU Architecture

Nowadays, the High Performance Computing is part of the context of embedded systems. Graphics Processing Units (GPUs) are more and more used in acceleration of the most part of algorithms and applications. Over the past years, not many efforts have been done to describe abstractions of applications in relation to their target architectures. Thus, when developers need to associate applications and GPUs, for example, they find difficulty and prefer using API for these architectures. This paper presents a metamodel extension for MARTE profile and a model for GPU architectures. The main goal is to specify the task and data allocation in the memory hierarchy of these architectures. The results show that this approach will help to generate code for GPUs based on model transformations using Model Driven Engineering (MDE).Comment: Symposium en Architectures nouvelles de machines (SympA'14) (2011