Delta-4 is a 5-nation, 13-partner project that has been investigating the achievement of dependability in open distributed systems, including real-time systems. This book describes the design and validation of the distributed fault-tolerant architecture developed within this project. The key features of the Delta-4 architecture are: (a) a distributed object-oriented application support environment; (b) built-in support for user-transparent fault tolerance; (c) use of multicast or group communication protocols; and (d) use of standard off the-shelf processors and standard local area network technology with minimum specialized hardware. The book is organized as follows: The first 3 chapters give an overview of the architecture's objectives and of the architecture itself, and compare the proposed solutions with other approaches. Chapters 4 to 12 give a more detailed insight into the Delta-4 architectural concepts. Chapters 4 and 5 are devoted to providing a firm set of general concepts and terminology regarding dependable and real-time computing. Chapter 6 is centred on fault-tolerance techniques based on distribution. The description of the architecture itself commences with a description of the Delta-4 application support environment (Deltase) in chapter 7. Two variants of the architecture - the Delta-4 Open System Architecture (OSA) and the Delta-4 Extra Performance Architecture (XPA) - are described respectively in chapters 8 and 9. Both variants of the architecture have a common underlying basis for dependable multicasting, i. e.

Comprehensive and up-to-date, it covers the most vital part of software development, independent verification and validation. Presents a variety of methods that will ensure better quality, performance, cost and reliability of technical products and systems. Features numerous hints, tips and instructions for better interaction between verification and validation personnel, development engineers and managers. Includes 8 case histories ranging from major engineering systems through information systems. Many of the principles involved also apply to computer hardware as well as the fields of science and engineering.

This book contains the 14th proceedings of the, very successful, International conference on Railway Engineering Design and Optimization (COMPRAIL 2014), which began in 1987. Encouraging the update and use of advanced systems, the book promotes their general awareness throughout the business management, design, manufacture and operation of railways and other emerging passenger, freight and transit systems. It particularly emphasises the use of computer systems in advanced railway engineering. Topics covered include: Timetable planning; Computer techniques and simulations; Actual train control; Operations quality; Risk management; Planning; Monitoring and maintenance; Energy supply and consumption; Communications and signalling; Rescheduling; Safety and security; Railway vehicle dynamics; Driverless and automatic train operation.