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The importance of using formal methods and techniques for verification of requirements in the automotive industry has been greatly emphasized with the introduction of the new ISO26262 standard for road vehicles functional safety. The lack of support for formal modeling of requirements still represents an obstacle for the adoption of the formal methods in industry. This paper presents a case study that has been conducted in order to evaluate the difficulties inherent to the process of transforming the system requirements from their traditional written form into semi-formal notation. The case study focuses on a set of non-structured functional requirements for the Electrical and Electronic (E/E) systems inside heavy road vehicles, written in natural language, and reassesses the applicability of the extended Specification Pattern System (SPS) represented in a restricted English grammar. Correlating this experience with former studies, we observe that, as previously claimed, the concept of patterns is likely to be generally applicable for the automotive domain. Additionally, we have identified some potential difficulties in the transformation process, which were not reported by the previous studies and will be used as a basis for further research.

With the ever-increasing size, complexity and intricacy of system requirements specifications, it becomes difficult to ensure their correctness with respect to certain criteria such as consistency. Automated formal techniques for consistency checking of requirements, mostly by means of model checking, have been proposed in academia. Sometimes such techniques incur a high modeling cost or analysis time, or are not applicable. To address such problems, in this paper we propose an automated consistency analysis technique of requirements that are formalized based on patterns, and checked using state-of-the-art Satisfiability Modulo Theories solvers. Our method assumes several transformation steps, from textual requirements to formal logic, and next into the format suited for the SMT tool. To automate such steps, we propose a tool, called PROPAS, that does not require any user intervention during the transformation and analysis phases, thus making the consistency analysis usable by non-expert practitioners. For validation, we apply our method on a set of timed computation tree logic requirements of an industrial automotive system called the Fuel Level Display.

Currently, Simulink models can be verified rigorously against design errors or statistical properties. In this paper, we show how Simulink models can be formally analyzed against invariance properties using bounded model checking reduced to satisfiability modulo theories solving. In its basic form, the technique provides means for verification of an underlying model over bounded traces rigorously, however, in general the procedure is incomplete. We identify common Simulink block types and compositions by analyzing selected industrial models, and we show that for some of them the set of non-repeating states (reachability diameter) can be visited with a finite set of paths of finite length, yielding the verification complete. We complement our approach with a tool, called SyMC that automates the following: i) calculation of the reachability diameter size for some of the designs, ii) generation of finite (bounded) paths of the underlying Simulink model and their encoding into SMT-LIB format and iii) checking invariance properties using the Z3 SMT solver. To show the applicability of our approach, we apply it on a prototype implementation of an industrial Simulink model, namely Brake by Wire from Volvo Group Trucks Technology, Sweden. 

With the ever-increasing size and complexity of the industrial software systems there is an imperative need for an automated, systematic and exhaustive verification of various software artifacts, such as system specifications, models, code, etc. A potential remedy for this need might lie in a pool of techniques for computer-aided verification of software related artifacts, including system specifications. The Achilles' heel of these techniques, and the main hinder for their wider adoption in industrial development process are the complexity and the specialized skill-set required for the formal encoding of specifications. To alleviate this problem, Specification Patterns that are based on the observation that the system specifications are framed within reoccurring solutions have been proposed. The approach has been shown to be expressive enough for capturing requirements in the automotive domain, however, there is a lack of empirical data that can be used to judge its practical usefulness. In this paper, we involve an existing specification-patterns-based tool, and propose a small-size evaluation of the approach with practitioners, on a case study conducted in cooperation with Scania, one of the world's leading manufacturers of heavy-load vehicles. Our results show that the specification patterns that are supported by an adequate tooling have the potential for adoption in industrial practice.