1,720,974 research outputs found
Automated Approaches for Formal Verification of Embedded Systems Artifacts
No full textModern embedded software is so large and complex that creating the necessary artifacts, including system requirements specifications and design-time models, as well as assuring their correctness have become difficult to manage. One challenge stems from the high number and intricacy of system requirements that combine functional and possibly timing or other types of constraints, which make them hard to analyze. Another challenge is the quality assurance of various design-time models developed using Simulink as the de facto standard model-based development tool in the automotive domain, avionics domain, etc. Currently, the industrial state-of-practice resorts to simulation of Simulink models, which gives insight in the system’s behavior yet does not provide a high degree of assurance that the model behaves correctly. A potential way to address the aforementioned challenges is to apply computer-aided, mathematically-rigorous methods for specification, analysis and verification already at the requirements specification stage, but also at later development stages. In this thesis, we propose a set of approaches for the formal specification, analysis and verification of system requirement specifications and design-time Simulink models, with particular focus on the automotive industry. Our contributions are as follows: first, we assess the expressiveness of an existing patternbased technique for the formal requirements specification on an operational system. Based on the positive findings, we deem the technique expressive enough to capture systems requirements in controlled natural language, from which formal counterparts can be automatically generated. To bring the approach closer to the practitioners we propose a tool, called PROPAS. Next, we propose an automated consistency analysis approach based on Satisfiability Modulo Theories for the system requirements specifications formally encoded as temporal logic formulas. The approach is implemented in our PROPAS tool and is suitable to analyze the lack of logical contradictions within the system specification, at early system development phases. Our next contribution addresses the formal analysis and verification of large Simulink models. First, we propose a pattern-based and execution-order-preserving approach for transforming Simulink models into networks of stochastic timed automata, which can be analyzed using the UPPAAL SMC tool that returns the probability that a property is satisfied by the model. For the automated generation of the analysis model, we propose the SIMPPAAL tool. Our second approach is based on bounded model checking and is suitable for checking invariance properties of Simulink models. Compared to the statistical model checking approach, the invariance checking is reduced to a satisfiability problem. In case of property violation, the procedure generates a counter-example execution trace, which can be used for refining the model. In the same work we show that there exist commonly-used design patterns in Simulink models, for which the verification result is complete. The approach is supported by our SYMC tool. For validation of the specification patterns, and the PROPAS tool we perform a case-study evaluation with practitioners, in collaboration with our industrial partner Scania. The results show that the pattern-based approach and the PROPAS tool can be practically useful in industrial settings. We apply the statistical model-checking approach and the SIMPPAAL tool on two industrial use cases, namely Brake-by-Wire and Adjustable Speed Limiter from Volvo Group Trucks Technology, which yields encouraging results. Finally, we validate the bounded invariance-checking approach and the SYMC tool on the Brake-by-Wire system, where we demonstrate both complete and incomplete verification of invariance properties.VeriSpe
Connecting a Design Framework for Service-oriented Systems with UPPAAL model-checker
No full textIn the context of Service-Oriented Systems (SOS), services represent loosely coupled discrete units that can be created, invoked, composed and decomposed upon a client request. In such a setting, where complex systems are composed out of services based on the client request, ensuring the expected level of Quality-of-Service (QoS) becomes a difficult task. In systems built on service-oriented principles, the formal specification of both functional and extra-functional system behavior, service availability, compatibility and interoperability between different services and systems have become important issues. To be compliant with the new features, the REMES language has been extended towards SOS with new constructs that have been given formal semantics. In this thesis, we propose transformation rules, definitions and techniques for transforming these new constructs into Timed Automata (TA) counterparts to facilitate the formal analysis. Also, we present an extension to an existing REMES SOS IDE toolset for performing an automated transformation of the REMES SOS models into the TA framework suitable for the formal analysis with the UPPAAL model-checker. The contribution from our work is on two fronts: a) define transformation rules for all of the constructs specific for the REMES SOS modeling and b) prototype implementation of the transformation rules as an extension add-on to the already existing IDE for modeling SOS to perform the automated transformation. The benefit of performing an automated transformation of the REMES SOS models in TA is twofold. First, by automating the transformation process, the process of validation of the models becomes faster. Second, we considerably reduce the influence from the human factor in the entire process, and at the same time lower the risks of introducing errors into the systems in the phase of creating the formal model. Additional benefit from the automated process is that the SOS designer does not have to be a verification expert in order to be able to verify the modeled system.
Increasing Embedded Systems´ Quality through Automated Specification and Analysis of Requirements and Behavioral Models
No full textPattern-based Specification and Formal Analysis of Embedded Systems Requirements and Behavioral Models
No full textSince the first lines of code were introduced in the automotive domain, vehicles have transitioned from being predominantly mechanical systems to software intensive systems. With the ever-increasing computational power and memory of vehicular embedded systems, a set of new, more powerful and more complex software functions are installed into vehicles to realize core functionalities. This trend impacts all phases of the system development including requirements specification, design and architecture of the system, as well as the integration and testing phases. In such settings, creating and managing different artifacts during the system development process by using traditional, human-intensive techniques becomes increasingly difficult. One problem stems from the high number and intricacy of system requirements that combine functional and possibly timing or other types of constraints. Another problem is related to the fact that industrial development relies on models, e.g. developed in Simulink, from which code may be generated, so the correctness of such models needs to be ensured. A potential way to address of the mentioned problems is by applying computer-aided specification, analysis and verification techniques already at the requirements stage, but also further at later development stages. Despite the high degree of automation, exhaustiveness and rigor of formal specification and analysis techniques, their integration with industrial practice remains a challenge. To address this challenge, in this thesis, we develop the foundation of a framework, tailored for industrial adoption, for formal specification and analysis of system requirements specifications and behavioral system models. First, we study the expressiveness of existing pattern-based techniques for creating formal requirements specifications, on a relevant industrial case study. Next, in order to enable practitioners to create formal system specification by using pattern-based techniques, we propose a tool called SeSAMM Specifier. Further, we provide an automated Satisfiability Modulo Theories (SMT)-based consistency analysis approach for the formally encoded system requirements specifications. The proposed SMT-based approach is suitable for early phases of the development for debugging the specifications. For the formal analysis of behavioral models, we provide an approach for statistical model checking of Simulink models by using the UPPAAL SMC tool. To facilitate the adoption of the approach, we provide the SIMPPAAL tool that automates procedure of generating network of stochastic timed automata for a given Simulink model. For validation, we apply our approach on a complex industrial model, namely the Brake-by-Wire function from Volvo GTT.VeriSpe
Pattern-based Specification and Formal Analysis of Embedded Systems Requirements and Behavioral Models
No full textSince the first lines of code were introduced in the automotive domain, vehicles have transitioned from being predominantly mechanical systems to software intensive systems. With the ever-increasing computational power and memory of vehicular embedded systems, a set of new, more powerful and more complex software functions are installed into vehicles to realize core functionalities. This trend impacts all phases of the system development including requirements specification, design and architecture of the system, as well as the integration and testing phases. In such settings, creating and managing different artifacts during the system development process by using traditional, human-intensive techniques becomes increasingly difficult. One problem stems from the high number and intricacy of system requirements that combine functional and possibly timing or other types of constraints. Another problem is related to the fact that industrial development relies on models, e.g. developed in Simulink, from which code may be generated, so the correctness of such models needs to be ensured. A potential way to address of the mentioned problems is by applying computer-aided specification, analysis and verification techniques already at the requirements stage, but also further at later development stages. Despite the high degree of automation, exhaustiveness and rigor of formal specification and analysis techniques, their integration with industrial practice remains a challenge. To address this challenge, in this thesis, we develop the foundation of a framework, tailored for industrial adoption, for formal specification and analysis of system requirements specifications and behavioral system models. First, we study the expressiveness of existing pattern-based techniques for creating formal requirements specifications, on a relevant industrial case study. Next, in order to enable practitioners to create formal system specification by using pattern-based techniques, we propose a tool called SeSAMM Specifier. Further, we provide an automated Satisfiability Modulo Theories (SMT)-based consistency analysis approach for the formally encoded system requirements specifications. The proposed SMT-based approach is suitable for early phases of the development for debugging the specifications. For the formal analysis of behavioral models, we provide an approach for statistical model checking of Simulink models by using the UPPAAL SMC tool. To facilitate the adoption of the approach, we provide the SIMPPAAL tool that automates procedure of generating network of stochastic timed automata for a given Simulink model. For validation, we apply our approach on a complex industrial model, namely the Brake-by-Wire function from Volvo GTT.VeriSpe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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