Enhancing Graphical Model-Based System Design: An Avionics Case Study

Graphical model-based system design is very appealing. However, there exist many different formalisms, with different semantics---as far as they do have well-defined semantics---and differing capabilities of the accompanying tools. In this paper, we present a case study from the avionics domain and report on the experiences in using different modeling languages and tools. The focus here is on the pragmatics of modeling, i. e., the practical process of building and inspecting graphical models. The underlying application is a high-lift ï¬ap system, which is highly safety-critical and served as a demonstrator within the Dependable Embedded Components and Systems (DECOS) project that explored the design of distributed dependable systems build on time-triggered architectures. Specifically, we compare a realization in the Safety Critical Application Development Environment (SCADE), a commercial tool from Esterel-Technologies, with a design in the Kiel Integrated Environment for Layout (KIEL), a research tool that allows to explore novel model handling paradigms. Hence we compare traditional graphical drag-and-drop WYSIWYG modeling with alternative, productivity enhancing approaches. We conclude with a brief outlook on future extensions which will tightly integrate with existing tools based on the Eclipse platform

Efficient development of complex statecharts

Modeling systems based on graphical formalisms, such as Statecharts, has become standard practice in the design of embedded devices. Using paradigms established so far often results in complex models that are difficult to comprehend and maintain. To overcome this, we present a methodology to support the easy development and understanding of complex Statecharts. Central to our approach is the use of secondary notations to aid readability. We employ an automated layout mechanism to transform any given Statechart to a Statechart Normal Form. The Kiel Integrated Environment for Layout is a prototypical modeling tool to explore our editing, browsing and simulation paradigms in the design of complex reactive systems. An empirical study on the usability and practicability of our Statechart editing techniques, including a Statechart layout comparison, indicates significant performance improvements in terms of editing speed and model comprehension compared to traditional modeling approaches

Analyzing Robustness of UML State Machines

UML State Machines constitute an integral part of software behavior specification within the Unified Modeling Language (UML). The development of realistic software applications often results in complex and distributed models. Hence, potential errors can be very subtle and hard to locate for the developer. In this paper, we present a set of robustness rules that seek to avoid common types of errors by ruling out certain modelling constructs. Furthermore, adherence to these rules can improve model readability and maintainability. The robustness rules constitute a general Statechart style guide for different dialects, such as UML State Machines, Statemate, and Esterel Studio. Based on this style guide, an automated checking framework has been implemented as a plug-in for the prototypical Statechart modeling tool KIEL. Simple structural checks can be formulated in a compact, abstract manner in the Object Constraint Language (OCL). The framework can also incorporate checks that go beyond the expressiveness of OCL by implementing them in Java directly, which can also serve as a gateway to formal verification tools; we have exploited this to incorporate a theorem prover for more advanced checks. As a case study, we adopted the UML well-formedness rules; this confirmed that individual rules can easily be incorporated into the framework

Über die Pragmatik der Graphischen Modellierung

Graphical models help to understand complex systems. However, with the user interaction paradigms established today, activities such as creating, maintaining or browsing graphical models can be very tedious. This thesis presents an approach to enhance productivity by focusing on the pragmatics of model-based design. The contribution includes an interpretation of the notion of pragmatics, orthogonal to syntax and semantics in Model-Driven Engineering (MDE). A proposal on pragmatics-aware modeling is given, employing sophisticated automated layout algorithms to close the gap between MDE and graph drawing theory. Thus, a view management logic presents customized views on models. These concepts get illustrated with the open source Kiel Integrated Environment for Layout Eclipse Rich Client (KIELER) with multiple applications including editing and simulation and shows how view management helps to tame complexity

Model-driven timing analysis of embedded software

Ph.DDOCTOR OF PHILOSOPH

Language Design for Reactive Systems: On Modal Models, Time, and Object Orientation in Lingua Franca and SCCharts

Reactive systems play a crucial role in the embedded domain. They continuously interact with their environment, handle concurrent operations, and are commonly expected to provide deterministic behavior to enable application in safety-critical systems. In this context, language design is a key aspect, since carefully tailored language constructs can aid in addressing the challenges faced in this domain, as illustrated by the various concurrency models that prevent the known pitfalls of regular threads. Today, many languages exist in this domain and often provide unique characteristics that make them specifically fit for certain use cases. This thesis evolves around two distinctive languages: the actor-oriented polyglot coordination language Lingua Franca and the synchronous statecharts dialect SCCharts. While they take different approaches in providing reactive modeling capabilities, they share clear similarities in their semantics and complement each other in design principles. This thesis analyzes and compares key design aspects in the context of these two languages. For three particularly relevant concepts, it provides and evaluates lean and seamless language extensions that are carefully aligned with the fundamental principles of the underlying language. Specifically, Lingua Franca is extended toward coordinating modal behavior, while SCCharts receives a timed automaton notation with an efficient execution model using dynamic ticks and an extension toward the object-oriented modeling paradigm

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues

Embedded System Design

A unique feature of this open access textbook is to provide a comprehensive introduction to the fundamental knowledge in embedded systems, with applications in cyber-physical systems and the Internet of things. It starts with an introduction to the field and a survey of specification models and languages for embedded and cyber-physical systems. It provides a brief overview of hardware devices used for such systems and presents the essentials of system software for embedded systems, including real-time operating systems. The author also discusses evaluation and validation techniques for embedded systems and provides an overview of techniques for mapping applications to execution platforms, including multi-core platforms. Embedded systems have to operate under tight constraints and, hence, the book also contains a selected set of optimization techniques, including software optimization techniques. The book closes with a brief survey on testing. This fourth edition has been updated and revised to reflect new trends and technologies, such as the importance of cyber-physical systems (CPS) and the Internet of things (IoT), the evolution of single-core processors to multi-core processors, and the increased importance of energy efficiency and thermal issues