400 research outputs found
A methodology for the requirements analysis of critical real-time systems
PhD ThesisThis thesis describes a methodology for the requirements analysis of critical real-time
systems. The methodology is based on formal methods, and provides a systematic way
in which requirements can be analysed and specifications produced. The proposed
methodology consists of a framework with distinct phases of analysis, a set oftechniques
appropriate for the issues to be analysed at each phase of the framework, a hierarchical
structure of the specifications obtained from the process of analysis, and techniques to
perform quality assessment of the specifications.
The phases of the framework, which are abstraction levels for the analysis of the
requirements, follow directly from a general structure adopted for critical real-time
systems. The intention is to define abstraction levels, or domains, in which the analysis
of requirements can be performed in terms of specific properties of the system, thus
reducing the inherent complexity of the analysis.
Depending on the issues to be analysed in each domain, the choice of the appropriate
formalism is determined by the set of features, related to that domain, that a formalism
should possess. In this work, instead of proposing new formalisms we concentrate on
identifying and enumerating those features that a formalism should have.
The specifications produced at each phase of the framework are organised by means of
a specification hierarchy, which facilitates our assessment of the quality of the
requirements specifications, and their traceability. Such an assessment should be
performed by qualitative and quantitative means in order to obtain high confidence
(assurance) that the level of safety is acceptable.
In order to exemplify the proposed methodology for the requirements analysis of critical
real-time systems we discuss a case study based on a crossing of two rail tracks (in a
model railway), which raises safety issues that are similar to those found at a traditional
level crossing (i.e. rail-road)CAPES/Ministry of Education (Brazil
Third NASA Langley Formal Methods Workshop
This publication constitutes the proceedings of NASA Langley Research Center's third workshop on the application of formal methods to the design and verification of life-critical systems. This workshop brought together formal methods researchers, industry engineers, and academicians to discuss the potential of NASA-sponsored formal methods and to investigate new opportunities for applying these methods to industry problems. contained herein are copies of the material presented at the workshop, summaries of many of the presentations, a complete list of attendees, and a detailed summary of the Langley formal methods program. Much of this material is available electronically through the World-Wide Web via the following URL
Formal methods and digital systems validation for airborne systems
This report has been prepared to supplement a forthcoming chapter on formal methods in the FAA Digital Systems Validation Handbook. Its purpose is as follows: to outline the technical basis for formal methods in computer science; to explain the use of formal methods in the specification and verification of software and hardware requirements, designs, and implementations; to identify the benefits, weaknesses, and difficulties in applying these methods to digital systems used on board aircraft; and to suggest factors for consideration when formal methods are offered in support of certification. These latter factors assume the context for software development and assurance described in RTCA document DO-178B, 'Software Considerations in Airborne Systems and Equipment Certification,' Dec. 1992
DAG-Based Attack and Defense Modeling: Don't Miss the Forest for the Attack Trees
This paper presents the current state of the art on attack and defense
modeling approaches that are based on directed acyclic graphs (DAGs). DAGs
allow for a hierarchical decomposition of complex scenarios into simple, easily
understandable and quantifiable actions. Methods based on threat trees and
Bayesian networks are two well-known approaches to security modeling. However
there exist more than 30 DAG-based methodologies, each having different
features and goals. The objective of this survey is to present a complete
overview of graphical attack and defense modeling techniques based on DAGs.
This consists of summarizing the existing methodologies, comparing their
features and proposing a taxonomy of the described formalisms. This article
also supports the selection of an adequate modeling technique depending on user
requirements
Development Process for Multi-Disciplinary Embedded Control Systems
This report contains the progress report for the qualification exam for Industrial PhD student Sune Wolff. Initial work on describing a development process for multi-disciplinary systems using collaborative modelling and co-simulation is described
Feasible, Robust and Reliable Automation and Control for Autonomous Systems
The Special Issue book focuses on highlighting current research and developments in the automation and control field for autonomous systems as well as showcasing state-of-the-art control strategy approaches for autonomous platforms. The book is co-edited by distinguished international control system experts currently based in Sweden, the United States of America, and the United Kingdom, with contributions from reputable researchers from China, Austria, France, the United States of America, Poland, and Hungary, among many others. The editors believe the ten articles published within this Special Issue will be highly appealing to control-systems-related researchers in applications typified in the fields of ground, aerial, maritime vehicles, and robotics as well as industrial audiences
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