A Design Pattern for Model Based Software Development for Automatic Machinery

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STL4IoT: A Statechart Template Library for IoT System Design

The engineering of IoT systems brings about various challenges due to the inherent complexities associated with such heterogeneous systems. In this paper, we propose a library of statechart templates, STL4IoT, for designing complex IoT systems. We have developed atomic statechart components modelling the heterogeneous aspects of IoT systems including sensors, actuators, physical entities, network, and controller. Base system units for smart systems have also been designed. A component for calculating power usage is available in the library. Additionally, a smart hub template that controls interactions among multiple IoT systems and manages power consumption has also been proposed. The templates aim to facilitate the modelling and simulation of IoT systems. Our work is demonstrated with a smart home system consisting of a smart hub of lights, a smart microwave, a smart TV, and a smart fire alarm system. We have created a multi statechart with itemis CREATE based on the proposed templates and components. A smart home simulator has been developed by generating controller code from the statechart and integrating it with a user interface

Increasing dependability in Safety Critical CPSs using Reflective Statecharts

Dependability is crucial in Safety Critical Cyber Physical Systems (CPS). In spite of the research carried out in recent years, implementation and certification of such systems remain costly and time consuming. In this paper, a framework for Statecharts based SW component development is presented. This framework called CRESC (C++ REflective StateCharts), in addition to assisting in transforming a Statechart model to code, uses reflection to make the model available at Run Time. Thus, the SW components can be monitored at Run Time in terms of model elements. Our framework helps the developer separate monitoring from functionality. Any monitoring strategy needed to increase dependability can be added independently from the functional part. The framework was implemented in C++ because this programming language, together with the Statechart formalism constitute widely used choices for the Safety Critical CPS domain

Towards an Integrated Approach to Verification and Model-Based Testing in System Engineering

yesEngineering design in general and system design of embedded software have a direct impact on the final engineering product and the software implementation, respectively. Guaranteeing that the models utilised meet the specified requirements is beneficial in detecting misbehaviour and software flaws. This requires an integrated approach, combining verification and model-based testing methodology and notations and methods from system engineering and software engineering. In this paper, we propose a model-based approach integrating various notations utilised in the functional design of complex systems with formal verification and testing. We illustrate our approach on the cruise control system of an e-Bike case study

Semantics and Verification of UML Activity Diagrams for Workflow Modelling

This thesis defines a formal semantics for UML activity diagrams that is suitable for workflow modelling. The semantics allows verification of functional requirements using model checking. Since a workflow specification prescribes how a workflow system behaves, the semantics is defined and motivated in terms of workflow systems. As workflow systems are reactive and coordinate activities, the defined semantics reflects these aspects. In fact, two formal semantics are defined, which are completely different. Both semantics are defined directly in terms of activity diagrams and not by a mapping of activity diagrams to some existing formal notation. The requirements-level semantics, based on the Statemate semantics of statecharts, assumes that workflow systems are infinitely fast w.r.t. their environment and react immediately to input events (this assumption is called the perfect synchrony hypothesis). The implementation-level semantics, based on the UML semantics of statecharts, does not make this assumption. Due to the perfect synchrony hypothesis, the requirements-level semantics is unrealistic, but easy to use for verification. On the other hand, the implementation-level semantics is realistic, but difficult to use for verification. A class of activity diagrams and a class of functional requirements is identified for which the outcome of the verification does not depend upon the particular semantics being used, i.e., both semantics give the same result. For such activity diagrams and such functional requirements, the requirements-level semantics is as realistic as the implementation-level semantics, even though the requirements-level semantics makes the perfect synchrony hypothesis. The requirements-level semantics has been implemented in a verification tool. The tool interfaces with a model checker by translating an activity diagram into an input for a model checker according to the requirements-level semantics. The model checker checks the desired functional requirement against the input model. If the model checker returns a counterexample, the tool translates this counterexample back into the activity diagram by highlighting a path corresponding to the counterexample. The tool supports verification of workflow models that have event-driven behaviour, data, real time, and loops. Only model checkers supporting strong fairness model checking turn out to be useful. The feasibility of the approach is demonstrated by using the tool to verify some real-life workflow models

A Case Study on Coloured Petri Nets in object-oriented analysis and design

Selected Papers of the Second International Workshop on Model-Based Methodologies for Pervasive and Embedded Software (MOMPES'05), June 6, 2005, Rennes, France.In this paper,we first demonstrate how a coloured Petri nets(CPN) model can be used to capture requirements for a considered example system, an elevator controller. Then, we show how this requirements-level CPN model is transformed into a design-level object-oriented CPN model, which is structurally and conceptually closer to class diagrams and object-oriented programming languages. The CPN models reduce the gap between user-level requirements and the respective implementation, thus simplifying the imple- mentation or code generation. Finally, we discuss the code generation from object-oriented CPN models