3,327 research outputs found

    Consistency of property specification patterns with boolean and constrained numerical signals

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    Property Specification Patterns (PSPs) have been proposed to solve recurring specification needs, to ease the formalization of requirements, and enable automated verification thereof. In this paper, we extend PSPs by considering Boolean as well as atomic numerical assertions. This extension enables us to reason about functional requirements which would not be captured by basic PSPs. We contribute an encoding from constrained PSPs to LTL formulae, and we show experimental results demonstrating that our approach scales on requirements of realistic size generated using a probabilistic model. Finally, we show that our extension enables us to prove (in)consistency of requirements about an embedded controller for a robotic manipulator

    Property specification patterns at work: verification and inconsistency explanation

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    Property specification patterns (PSPs) have been proposed to ease the formalization of requirements, yet enable automated verification thereof. In particular, the internal consistency of specifications written with PSPs can be checked automatically with the use of, for example, linear temporal logic (LTL) satisfiability solvers. However, for most practical applications, the expressiveness of PSPs is too restricted to enable writing useful requirement specifications, and proving that a set of requirements is inconsistent can be worthless unless a minimal set of conflicting requirements is extracted to help designers to correct a wrong specification. In this paper, we extend PSPs by considering Boolean as well as atomic numerical assertions, we contribute an encoding from extended PSPs to LTL formulas, and we present an algorithm computing inconsistency explanations, i.e., irreducible inconsistent subsets of the original set of requirements. Our extension enables us to reason about the internal consistency of functional requirements which would not be captured by basic PSPs. Experimental results demonstrate that our approach can check and explain (in)consistencies in specifications with nearly two thousand requirements generated using a probabilistic model, and that it enables effective handling of real-world case studies

    Formal Requirements Analysis and Specification-Based Testing in Cyber-Physical Systems

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    openFormal requirements analysis plays an important role in the design of safety- and security-critical complex systems such as, e.g., Cyber-Physical Systems (CPS). It can help in detecting problems early in the system development life-cycle, reducing time and cost to completion. Moreover, its results can be employed at the end of the process to validate the implemented system, guiding the testing phase. Despite its importance, requirements analysis is still largely carried out manually due to the intrinsic difficulty of dealing with natural language requirements, the most common way to represent them. However, manual reviews are time-consuming and error-prone, reducing the potential benefit of the requirement engineering process. Automation can be achieved with the employment of formal methods, but their application is still limited by their complexity and lack of specialized tools. In this work we focus on the analysis of requirements for the design of CPSs, and on how to automatize some activities related to such analysis. We first study how to formalize requirements expressed in a structured English language, encode them in linear temporal logic, check their consistency with off-the-shelf model checkers, and find minimal set of conflicting requirements in case of inconsistency. We then present a new methodology to automatically generate tests from requirements and execute them on a given system, without requiring knowledge of its internal structure. Finally, we provide a set of tools that implement the studied algorithms and provide easy-to-use interfaces to help their adoption from the users.openXXXIII CICLO - INFORMATICA E INGEGNERIA DEI SISTEMI/ COMPUTER SCIENCE AND SYSTEMS ENGINEERING - Informatica/computer sciencePULINA, LUCAVuotto, Simon

    Poster: Automatic Consistency Checking of Requirements with ReqV

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    In the context of Requirements Engineering, checking the consistency of functional requirements is an important and still mostly open problem. In case of requirements written in natural language, the corresponding manual review is time consuming and error prone. On the other hand, automated consistency checking most often requires overburdening formalizations. In this paper we introduce REQV, a tool for formal consistency checking of requirements. The main goal of the tool is to provide an easy-to-use environment for the verification of requirements in Cyber-Physical Systems (CPS). REQV takes as input a set of requirements expressed in a structured natural language, translates them in a formal language and it checks their inner consistency. In case of failure, REQV can also extracts a minimal set of conflicting requirements to help designers in correcting the specification

    Z2SAL: a translation-based model checker for Z

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    Despite being widely known and accepted in industry, the Z formal specification language has not so far been well supported by automated verification tools, mostly because of the challenges in handling the abstraction of the language. In this paper we discuss a novel approach to building a model-checker for Z, which involves implementing a translation from Z into SAL, the input language for the Symbolic Analysis Laboratory, a toolset which includes a number of model-checkers and a simulator. The Z2SAL translation deals with a number of important issues, including: mapping unbounded, abstract specifications into bounded, finite models amenable to a BDD-based symbolic checker; converting a non-constructive and piecemeal style of functional specification into a deterministic, automaton-based style of specification; and supporting the rich set-based vocabulary of the Z mathematical toolkit. This paper discusses progress made towards implementing as complete and faithful a translation as possible, while highlighting certain assumptions, respecting certain limitations and making use of available optimisations. The translation is illustrated throughout with examples; and a complete working example is presented, together with performance data

    Fault tolerant architectures for integrated aircraft electronics systems, task 2

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    The architectural basis for an advanced fault tolerant on-board computer to succeed the current generation of fault tolerant computers is examined. The network error tolerant system architecture is studied with particular attention to intercluster configurations and communication protocols, and to refined reliability estimates. The diagnosis of faults, so that appropriate choices for reconfiguration can be made is discussed. The analysis relates particularly to the recognition of transient faults in a system with tasks at many levels of priority. The demand driven data-flow architecture, which appears to have possible application in fault tolerant systems is described and work investigating the feasibility of automatic generation of aircraft flight control programs from abstract specifications is reported

    Designing Trustworthy Autonomous Systems

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    The design of autonomous systems is challenging and ensuring their trustworthiness can have different meanings, such as i) ensuring consistency and completeness of the requirements by a correct elicitation and formalization process; ii) ensuring that requirements are correctly mapped to system implementations so that any system behaviors never violate its requirements; iii) maximizing the reuse of available components and subsystems in order to cope with the design complexity; and iv) ensuring correct coordination of the system with its environment.Several techniques have been proposed over the years to cope with specific problems. However, a holistic design framework that, leveraging on existing tools and methodologies, practically helps the analysis and design of autonomous systems is still missing. This thesis explores the problem of building trustworthy autonomous systems from different angles. We have analyzed how current approaches of formal verification can provide assurances: 1) to the requirement corpora itself by formalizing requirements with assume/guarantee contracts to detect incompleteness and conflicts; 2) to the reward function used to then train the system so that the requirements do not get misinterpreted; 3) to the execution of the system by run-time monitoring and enforcing certain invariants; 4) to the coordination of the system with other external entities in a system of system scenario and 5) to system behaviors by automatically synthesize a policy which is correct

    EOOLT 2007 – Proceedings of the 1st International Workshop on Equation-Based Object-Oriented Languages and Tools

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    Computer aided modeling and simulation of complex systems, using components from multiple application domains, such as electrical, mechanical, hydraulic, control, etc., have in recent years witness0065d a significant growth of interest. In the last decade, novel equation-based object-oriented (EOO) modeling languages, (e.g. Mode- lica, gPROMS, and VHDL-AMS) based on acausal modeling using equations have appeared. Using such languages, it has become possible to model complex systems covering multiple application domains at a high level of abstraction through reusable model components. The interest in EOO languages and tools is rapidly growing in the industry because of their increasing importance in modeling, simulation, and specification of complex systems. There exist several different EOO language communities today that grew out of different application areas (multi-body system dynamics, electronic circuit simula- tion, chemical process engineering). The members of these disparate communities rarely talk to each other in spite of the similarities of their modeling and simulation needs. The EOOLT workshop series aims at bringing these different communities together to discuss their common needs and goals as well as the algorithms and tools that best support them. Despite the short deadlines and the fact that this is a new not very established workshop series, there was a good response to the call-for-papers. Thirteen papers and one presentation were accepted to the workshop program. All papers were subject to reviews by the program committee, and are present in these electronic proceedings. The workshop program started with a welcome and introduction to the area of equa- tion-based object-oriented languages, followed by paper presentations and discussion sessions after presentations of each set of related papers. On behalf of the program committee, the Program Chairmen would like to thank all those who submitted papers to EOOLT'2007. Special thanks go to David Broman who created the web page and helped with organization of the workshop. Many thanks to the program committee for reviewing the papers. EOOLT'2007 was hosted by the Technical University of Berlin, in conjunction with the ECOOP'2007 conference
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