A Case-Study on Manual Verification of State-based Source Code Generated by KIELER SCCharts

Statecharts-like languages, such as SCCharts, are commonly used to develop stateoriented reactive and critical systems. Code is often generated by automatic code generators, which employ different strategies. This paper presents the results of a second user study on manual user verification of different source codes, which were generated using a netlist-based, a priority-based, and a state-based code generation approach compiling SCCharts models to C. The evaluation shows that manual verification can be time-consuming and is error prone if the user has no clear mapping between states and transition of the original model and the generated code. The participants performed better if the generated code followed a state pattern that preserves original model structures and names

Steam Package Boiler Expert System for Control and Maintenance of Fertilizer Plants using Rule-Base Fuzzy Logic

Generally, expert systems have been found very useful and even in fertilizer plants it has been deployed in handling operations in critical sections, such as material handling systems, online detection systems, granulation, air compressor among others. This paper presents research work for steam package boiler expert system for control and maintenance of fertilizer plants using rule-base fuzzy logic hybrid system, which has not been benefited much from expert system. The system handles cause of boiler failures in terms of controlling and maintaining the functional chemical components of the boiler drum and feed water parameters. validation on the system consistency, correctness, and its precision with six (6) steam package boiler parameters test value cases was conducted involving fourteen (14) fertilizer plant boiler domain partitioners. The boiler drum and feed water qualities with less or higher test value worst-cases validates the boiler system, showing each of the parameters bar turns red, as displayed on the boilers panel, while on test value best-cases, validates the system, displaying green on the boilers panel bar as users entered the right value of parameters as design specification. The expert system prevents damaged and malfunctioning as control the alkalinity, prevent scaling, both mechanica

Software Development Technologies for Reactive, Real-Time, and Hybrid Systems

The research is directed towards the design and implementation of a comprehensive deductive environment for the development of high-assurance systems, especially reactive (concurrent, real-time, and hybrid) systems. Reactive systems maintain an ongoing interaction with their environment, and are among the most difficult to design and verify. The project aims to provide engineers with a wide variety of tools within a single, general, formal framework in which the tools will be most effective. The entire development process is considered, including the construction, transformation, validation, verification, debugging, and maintenance of computer systems. The goal is to automate the process as much as possible and reduce the errors that pervade hardware and software development

A Formal Component-Based Software Engineering Approach For Developing Trustworty Systems

Software systems are increasingly becoming ubiquitous, affecting the way we experience the world. Embedded software systems, especially those used in smart devices, have become an essential constituent of the technological infrastructure of modern societies. Such systems, in order to be trusted in society, must be proved to be trustworthy. Trustworthiness is a composite non-functional property that implies safety, timeliness, security, availability, and reliability. This thesis is a contribution to a rigorous development of systems in which trustworthiness property can be specified and formally verified. Developing trustworthy software systems that are complex and used by a large heterogeneous population of users is a challenging task. The component-based software engineering (CBSE) paradigm can provide an effective solution to address these challenges. However, none of the current component-based approaches can be used as is, because all of them lack the essential requirements for constructing trustworthy systems. The three contributions made in this thesis are intended to add to the expressive power needed to raise CBSE practices to a rigorous level for constructing formally verifiable trustworthy systems. The first contribution of the thesis is a formal definition of the trustworthy component model. The trustworthiness quality attributes are introduced as first class structural elements. The behavior of a component is automatically generated as an extended timed automata. A model checking technique is used to verify the properties of trustworthiness. A composition theory that preserves the properties of trustworthiness in a composition is presented. Conventional software engineering development processes are not suitable either for developing component-based systems or for developing trustworthy systems. In order to develop a component-based trustworthy system, the development process must be reuseoriented,component-oriented, and must integrate formal languages and rigorous methods in all phases of system life-cycle. The second contribution of the thesis is a software engineering process model that consists of several parallel tracks of activities including component development, component assessment, component reuse, and component-based system development. The central concern in all activities of this process is ensuring trustworthiness. The third and final contribution of the thesis is a development framework with a comprehensive set of tools supporting the spectrum of formal development activity from modeling to deployment. The proposed approach has been applied to several case studies in the domains of component-based development and safety-critical systems. The experience from the case studies confirms that the approach is suitable for developing large and complex trustworthy systems

A formal component-based software engineering approach for developing trustworthy systems

Software systems are increasingly becoming ubiquitous, affecting the way we experience the world. Embedded software systems, especially those used in smart devices, have become an essential constituent of the technological infrastructure of modem societies. Such systems, in order to be trusted in society, must be proved to be trustworthy. Trustworthiness is a composite non-functional property that implies safety, timeliness, security, availability, and reliability. This thesis is a contribution to a rigorous development of systems in which trustworthiness property can be specified and formally verified. Developing trustworthy software systems that are complex and used by a large heterogenous population of users is a challenging task. The component-based software engineering (CBSE) paradigm can provide an effective solution to address these challenges. However, none of the current component-based approaches can be used as is, because all of them lack the essential requirements for constructing trustworthy systems. The three contributions made in this thesis are intended to add to the expressive power needed to raise CBSE practices to a rigorous level for constructing formally verifiable trustworthy systems. The first contribution of the thesis is a formal definition of the trustworthy component model. The trustworthiness quality attributes are introduced as first class structural elements. The behavior of a component is automatically generated as an extended timed automata. A model checking technique is used to verify the properties of trustworthiness. A composition theory that preserves the properties of trustworthiness in a composition is presented. Conventional software engineering development processes are not suitable either for developing component-based systems or for developing trustworthy systems. In order to develop a component-based trustworthy system, the development process must be reuse-oriented, component-oriented, and must integrate formal languages and rigorous methods in all phases of system life-cycle. The second contribution of the thesis is a software engineering process model that consists of several parallel tracks of activities including component development, component assessment, component reuse, and component-based system development. The central concern in all activities of this process is ensuring trustworthiness. The third and final contribution of the thesis is a development framework with a comprehensive set of tools supporting the spectrum of formal development activity from modeling to deployment. The proposed approach has been applied to several case studies in the domains of component-based development and safety-critical systems. The experience from the case studies confirms that the approach is suitable for developing large and complex trustworthy systems

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

UTP, Circus, and Isabelle

We dedicate this paper with great respect and friendship to He Jifeng on the occasion of his 80th birthday. Our research group owes much to him. The authors have over 150 publications on unifying theories of programming (UTP), a research topic Jifeng created with Tony Hoare. Our objective is to recount the history of Circus (a combination of Z, CSP, Dijkstra’s guarded command language, and Morgan’s refinement calculus) and the development of Isabelle/UTP. Our paper is in two parts. (1) We first discuss the activities needed to model systems: we need to formalise data models and their behaviours. We survey our work on these two aspects in the context of Circus. (2) Secondly, we describe our practical implementation of UTP in Isabelle/HOL. Mechanising UTP theories is the basis of novel verification tools. We also discuss ongoing and future work related to (1) and (2). Many colleagues have contributed to these works, and we acknowledge their support