17th IEEE Real-Time Systems Symposium: Work in Progress Sessions

The Table of Contents for the workshop is contained in 1996-027-00main.pdfDear Colleagues: This year marks the beginning of a new tradition within the Real-Time Systems Symposium, that of holding special sessions for the presentation of new and on-going projects in real-time systems. The prime purpose of these Work In Progress (WIP) sessions is to provide researchers in Academia and Industry an opportunity to discuss their evolving ideas and gather feedback thereon from the real-time community at large. The idea of holding these sessions is timely, and I am pleased to report that this year RTSS'96 WIP received 22 submissions, of which 14 have been accepted for presentation during the symposium and for inclusion in RTSS'96 WIP proceedings. Many people worked hard to make the idea of holding the WIP sessions a reality. In particular, I would like to thank Sang Son for his hard work in accommodating the WIP sessions within the busy schedule of RTSS'96. Also, I would like to thank all members of the RTSS'96 Program Committee, Al Mok and Doug Locke in particular, for their encouragement and constructive feedback regarding the organization of these sessions. Finally, I would like to thank all those who submitted their work to RTSS'96 WIP and those from RTSS'96 program committee who helped review these submissions. I hope these sessions will prove beneficial, both to the WIP presenters and to RTSS'96 attendees. Azer Bestavros RTSS'96 WIP Chair December 1996.IEEE-CS TC-RT

Managing Complexity in Software Development with Formally Based Tools

Over the past two decades, formal methods researchers have produced a number of powerful software tools designed to detect errors in, and to verify properties of, hardware designs, software systems, and software system artifacts. Mostly used in the past to debug hardware designs, in future years, these tools should help developers improve the quality of software systems. They should be especially useful in developing high assurance software systems, where compelling evidence is required that the system satisfies critical properties, such as safety and security. This paper describes the di#erent roles that formally based software tools can play in improving the correctness of software and software artifacts. Such tools can help developers manage complexity by automatically exposing certain classes of software errors and by producing evidence (e.g., mechanically checked proofs, results of executing automatically generated test cases, etc.) that a software system satisfies its requirements. In addition, the tools allow practitioners to focus on development tasks best performed by people---e.g., obtaining and validating requirements and constructing a high-quality requirements specification

Requirements Specifications For Hybrid Systems

this paper is to present a formal framework for representing and reasoning about the requirements of hybrid systems. As background, the paper briefly reviews an abstract model for specifying system and software requirements, called the Four Variable Model [12], and a related requirements method, called SCR (Software Cost Reduction) [10, 1]. The paper then introduces a special discrete version of the Four Variable Model, the SCR requirements model [8] and proposes an extension of the SCR model for specifying and reasoning about hybrid systems. 2 Backgroun

On the Need for Practical Formal Methods

A controversial issue in the formal methods community is the degree to which mathematical sophistication and theorem proving skills should be needed to apply a formal method. A fundamental assumption of this paper is that formal methods research has produced several classes of analysis that can prove useful in software development. However, to be useful to software practitioners, most of whom lack advanced mathematical training and theorem proving skills, current formal methods need a number of additional attributes, including more userfriendly notations, completely automatic (i.e., pushbutton) analysis, and useful, easy to understand feedback. Moreover, formal methods need to be integrated into a standard development process. I discuss additional research and engineering that is needed to make the current set of formal methods more practical. To illustrate the ideas, I present several examples, many taken from the SCR (Software Cost Reduction) requirements method, a formal method th..

Formal Methods for Specifying Validating, and Verifying Requirements

During the past three decades, many formal methods have been proposed whose purpose is to reduce the cost of constructing computer systems and to improve their quality. Informally, a formal method is a mathematically-based technique or too

The Generalized Railroad Crossing: A Case Study in Formal Verification of Real-Time Systems

A new solution to the Generalized Railroad Crossing problem, based on timed automata, invariants and simulation mappings, is presented and evaluated. The solution shows formally the correspondence between four system descriptions: an axiomatic specification, an operational specification, a discrete system implementation, and a system implementation that works with a continuous gate model