Formalization and Validation of Safety-Critical Requirements

The validation of requirements is a fundamental step in the development process of safety-critical systems. In safety critical applications such as aerospace, avionics and railways, the use of formal methods is of paramount importance both for requirements and for design validation. Nevertheless, while for the verification of the design, many formal techniques have been conceived and applied, the research on formal methods for requirements validation is not yet mature. The main obstacles are that, on the one hand, the correctness of requirements is not formally defined; on the other hand that the formalization and the validation of the requirements usually demands a strong involvement of domain experts. We report on a methodology and a series of techniques that we developed for the formalization and validation of high-level requirements for safety-critical applications. The main ingredients are a very expressive formal language and automatic satisfiability procedures. The language combines first-order, temporal, and hybrid logic. The satisfiability procedures are based on model checking and satisfiability modulo theory. We applied this technology within an industrial project to the validation of railways requirements

Design of Transmission Pipeline Modeling Language

General purpose software design and development involves the repetition of many processes, and the ability to automate these processes is often desired. To formalize a software process, such as modelling pipeline systems that transport fluids, an existing general purpose programming language (GPL) can be extended with its important aspects extracted as a model. However, the complexities and boundaries the programming language places on the ability to concisely and clearly describe the designing and modelling processes of the pipeline configurations can be difficult. The reality is that the library of a typical GPL Application Programmers Interface (API) constitutes class, method, and function names that become available only by object creation and method invocation, and as such cannot express domain concepts effectively. An alternative approach is to develop a language specifically for describing the processes. A language formalism that encourages domain specific development and as a tool for solving the complex problem of efficiently and effectively aiding the pipeline engineer in the design and implementation of pipeline configurations is presented in this paper. The language tool is used on the .Net platform for domain specific software development

Construction of formal models and verifying property specifications through an example of railway interlocking systems

Abstract The use of formal modeling has seen an increasing interest in the development of safety-critical, embedded microcomputer-controlled railway interlocking systems, due to its ability to specify the behavior of the systems using mathematically precise rules. The research goal is to prepare a specification-verification environment, which supports the developer of the railway interlocking systems in the creation of a formally-proven correct design and at the same time hides the inherent mathematical-computer since related background knowledge. The case study is presented with the aim to summarize the process of formalizing a domain specification, and to show further application possibilities (e.g. verification methods)

Safety-oriented Testing for High-speed Rail Onboard Equipment Using Petri Nets

With its ability to operate at high speeds and capacity, high-speed rail offers a fast, dependable, and ecofriendly urban transportation option. Safety-critical systems such as high-speed rail signaling systems must be tested regularly to assess compliance with specifications and ensure reliable performance. Given that the onboard equipment is the core component of the signaling system, conducting safety testing on this equipment is of utmost importance. Current methods of analyzing test requirements mainly rely on human interpretation of specifications. However, the official technical specifications usually only outline standard operational scenarios, which could result in an inefficient and unclear safety analysis. This paper focuses on safety-oriented testing for onboard equipment. In particular, we propose a Petri net based approach to generate test cases for diverse operational scenarios. This approach improves both the efficiency and reliability of the testing process while ensuring compliance with safety requirements

Knowledge-Intensive Processes: Characteristics, Requirements and Analysis of Contemporary Approaches

Engineering of knowledge-intensive processes (KiPs) is far from being mastered, since they are genuinely knowledge- and data-centric, and require substantial flexibility, at both design- and run-time. In this work, starting from a scientific literature analysis in the area of KiPs and from three real-world domains and application scenarios, we provide a precise characterization of KiPs. Furthermore, we devise some general requirements related to KiPs management and execution. Such requirements contribute to the definition of an evaluation framework to assess current system support for KiPs. To this end, we present a critical analysis on a number of existing process-oriented approaches by discussing their efficacy against the requirements

Marinas and other ports and facilities for the recreational craft sector: an ontology domain to support spatial planning.

Marinas and other ports and facilities for the recreational craft sector in Sardinia (Italy) can host more than 19,000 pleasure boats and yachts, according to a recent estimate (Osservatorio Nautico Nazionale, 2010); this capacity, at the national level, is second only to that of the Liguria region. However, Sardinian infrastructures and facilities are not part of a coherent network. Moreover, they are unevenly scattered along the coastline and are very diverse, in terms of type, dimension, and endowment of facilities for sailors. A key issue to be taken into account in the early stages of the preparation of a plan for the pleasure craft sector, which might create the conditions for the setting up of a coherent network, is the lack of a proper, detailed knowledge of the system of Sardinian marinas and other facilities. To this end, this paper begins with an analysis of current information (both spatial and non-spatial) and attempts to build a spatial database that integrates available data. The analysis identifies differences in structure and semantics, together with differences in purpose and date of production/update of the data, as the roots of inconsistencies among existing data produced by different sources. Such differences in structure and semantics risk, if not properly identified, considered and handled, to cause an incorrect integration of data. Following the methodology provided by the guidelines produced by the Ordnance Survey with regards to domain ontologies (Hart et al., 2007; Hart e Goodwin, 2007; Kovacs et al., 2006), the construction of an ontology of the domain of infrastructure and facilities for the recreational craft sector is therefore proposed as a possible solution to the problem. By applying this methodology, a ‘knowledge glossary,’ consisting of a shared vocabulary of core and secondary concepts and of relationships (some of which spatial) among concepts is developed, leading to the construction of a conceptual model of the domain, later formalized by means of the software Protégé.

Using Ontologies in Formal Developments Targeting Certification

This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this recordIFM 2019: 15th International Conference on integrated Formal Methods, 4-6 December 2019, Bergen, NorwayA common problem in the certification of highly safety or security critical systems is the consistency of the certification documentation in general and, in particular, the linking between semi-formal and formal content of the certification documentation. We address this problem by using an existing framework, Isabelle/DOF, that allows writing certification documents with consistency guarantees, in both, the semi-formal and formal parts. Isabelle/DOF supports the modeling of document ontologies using a strongly typed ontology definition language. An ontology is then enforced inside documents including formal parts, e.g., system models, verification proofs, code, tests and validations of corner-cases. The entire set of documents is checked within Isabelle/HOL, which includes the definition of ontologies and the editing of integrated documents based on them. This process is supported by an IDE that provides continuous checking of the document consistency. In this paper, we present how a specific software-engineering certification standard, namely CENELEC 50128, can be modeled inside Isabelle/DOF. Based on an ontology covering a substantial part of this standard, we present how Isabelle/DOF can be applied to a certification case-study in the railway domain.IRT System

Modeling of Secure and Dependable Applications Based on a Repository of Patterns: The SEMCO Approach

International audienceThe requirement for higher quality and seamless development of systems is continuously increasing, even in domains traditionally not deeply involved in such issues. Security and Dependability (S&D) requirements are incorporated to an increasing number of systems. These newer restrictions make the development of those systems more complicated than conventional systems. In our work, we promote a new approach called SEMCO (System and software Engineering with Multi-COncerns) combining Model-Driven Engineering (MDE) with a model-based repository of S&D patterns to support the design and the analysis of pattern-based secure and dependable system and software architectures. The modeling framework to support the approach is based on a set of modeling languages, to specify security and dependability patterns, resources and a set of property models, and a set of model transformation rules to specify some of the analysis activities. As part of the assistance for the development of S&D applications, we have implemented a tool-chain based on the Eclipse platform to support the different activities around the repository, including the analysis activities. The proposed approach was evaluated through a case study from the railway domain