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

Formal Requirements Elicitation with FRET

FRET is a tool for writing, understanding, formalizing and analyzing requirements. Users write requirements in an intuitive, restricted natural language, called FRETISH, with precise, unambiguous meaning. For a FRETISH requirement, FRET: 1) produces natural language and diagrammatic explanations of its exact meaning, 2) formalizes the requirement in logics, and 3) supports interactive simulation of produced logic formulas to ensure that they capture user intentions. FRET connects to analysis tools by facilitating the mapping between requirements and models/code, and by generating verification code. FRET is available open source at https://github.com/NASA-SW-VnV/fret; a video can be accessed at : https://tinyurl.com/fretForREFSQ

Automating the Object-Oriented Software Development Process: Workshop Report

Cost-effective realization of robust, adaptable and reusable software systems demands efficient and effective management of the overall software production process. Current object-oriented methods are not completely formalized and lack the ability of reasoning about the quality of processes and software products (artifacts). There is a need for new modeling formalisms, which enable the quantification of the required quality attributes and support the automation of the object-oriented development process (AOOSD). The ECOOP'98 AOOSD workshop was organized to identify the important issues in this direction

Software development: A paradigm for the future

A new paradigm for software development that treats software development as an experimental activity is presented. It provides built-in mechanisms for learning how to develop software better and reusing previous experience in the forms of knowledge, processes, and products. It uses models and measures to aid in the tasks of characterization, evaluation and motivation. An organization scheme is proposed for separating the project-specific focus from the organization's learning and reuse focuses of software development. The implications of this approach for corporations, research and education are discussed and some research activities currently underway at the University of Maryland that support this approach are presented

An IMS-Learning Design Editor for a Higher Education Blended Learning Scenario

The IMS-Learning Design has been developed to support the creation of reusable and pedagogically neutral learning scenarios and content. Although it is especially suitable for eLearning, there is a lot of interest on using it in higher education blended learning scenarios. However there are some related key issues which must be managed such as cultural bias and the need for expensive human resources to design and develop specification compliant units of learning. They can be addressed by the design of ad-hoc editors supporting concrete learning design units of learning. We suggest some solutions to overcome these limitations, based on our experience designing the user interface of an IMS-LD compliant editor, GDUS+. We also explain our user centering approach, and give some conclusions about the benefits of using IMS-LD