Distributed systems : architecture-driven specification using extended LOTOS

The thesis uses the LOTOS language (ISO International Standard ISO 8807) as a basis for the formal specification of distributed systems. Contributions are made to two key research areas: architecture-driven specification and LOTOS language extensions. The notion of architecture-driven specification is to guide the specification process by providing a reference-base of pre-defined domain-specific components. The thesis builds an infra-structure of architectural elements, and provides Extended LOTOS (XL) definitions of these elements. The thesis develops Extended LOTOS (XI.) for the specification of distributed systems. XL- is LOTOS enhanced with features for the formal specification of quantitative timing. probabilistic and priority requirements. For distributed systems, the specification of these ‘performance’ requirements, ran be as important as the specification of the associated functional requirements. To support quantitative timing features, the XL semantics define a global, discrete clock which can be used both to force events to occur at specific times, and to measure Intervals between event occurrences. XL introduces time policy operators ASAP (as soon as possible’ corresponding to “maximal progress semantics") and ALAP (late as possible'). Special internal transitions are introduced in XL semantics for the specification of probability, Conformance relations based on a notion of probabilization, together with a testing framework, are defined to support reasoning about probabilistic XL specifications. Priority within the XL semantics ensures that permitted events with the highest priority weighting of their class are allowed first. Both functional and performance specification play important roles in CIM (Computer Integrated Manufacturing) systems. The thesis uses a CIM system known as the CIM- OSA lntegrating Infrastructure as a case study of architecture-driven specification using XL. The thesis thus constitutes a step in the evolution of distributed system specification methods that have both an architectural basis and a formal basis

Space Transportation System and associated payloads: Glossary, acronyms, and abbreviations

A collection of acronyms now in everyday use in the Shuttle world are listed. It is a combination of lists that were prepared at the Kennedy and Johnson Space Centers and by the Air Force

Space Transportation System and associated payloads: Glossary, acronyms, and abbreviations

A collection of acronyms in everyday use concerning shuttle activities is presented. A glossary of terms pertaining to the Space Transportation System is included

Space transportation system and associated payloads: Glossary, acronyms, and abbreviations

A collection of some of the acronyms and abbreviations now in everyday use in the shuttle world is presented. It is a combination of lists that were prepared at Marshall Space Flight Center and Kennedy and Johnson Space Centers, places where intensive shuttle activities are being carried out. This list is intended as a guide or reference and should not be considered to have the status and sanction of a dictionary

The 1992 4th NASA SERC Symposium on VLSI Design

Papers from the fourth annual NASA Symposium on VLSI Design, co-sponsored by the IEEE, are presented. Each year this symposium is organized by the NASA Space Engineering Research Center (SERC) at the University of Idaho and is held in conjunction with a quarterly meeting of the NASA Data System Technology Working Group (DSTWG). One task of the DSTWG is to develop new electronic technologies that will meet next generation electronic data system needs. The symposium provides insights into developments in VLSI and digital systems which can be used to increase data systems performance. The NASA SERC is proud to offer, at its fourth symposium on VLSI design, presentations by an outstanding set of individuals from national laboratories, the electronics industry, and universities. These speakers share insights into next generation advances that will serve as a basis for future VLSI design

Shuttle mission simulator requirements report, volume 1, revision C

The contractor tasks required to produce a shuttle mission simulator for training crew members and ground personnel are discussed. The tasks will consist of the design, development, production, installation, checkout, and field support of a simulator with two separate crew stations. The tasks include the following: (1) review of spacecraft changes and incorporation of appropriate changes in simulator hardware and software design, and (2) the generation of documentation of design, configuration management, and training used by maintenance and instructor personnel after acceptance for each of the crew stations

A study of process improvement activities for web development processes within a small company

This thesis describes activities carried out in order to improve a small company's web development process, specifically focusing on the areas of reuse and web accessibility. CACDP are the examinations board for British Sign Language and other related disciplines. Within the domain of web development they have no formal processes and no skills or knowledge with which to improve them. They wish to develop four new web based products, and to apply accessibility guidelines to both these and their existing web site. The areas of web development, process Improvement and reuse are investigated, specifically In relation to their suitability for CACDP, and an action list is drawn up of tasks that will assist them in achieving their aims. A formal process is defined and implemented in an iterative procedure, designed to gradually improve their working practices, and work towards achieving improvements in some of the Key Process Areas of the Capability Maturity Model. Reuse is targeted as a specific way to achieve efficiency within the development, and web accessibility is particularly important to CACDP as they work with many people who are affected by the lack of accessibility. The thesis describes the production of the applications using the defined process, and the problems faced during the implementation. These problems are reviewed and suggested improvements are integrated into the next implementation of the process. This project has resulted in the successful introduction of a formal process for the development of web-based applications. Reuse is now being used within the company to reduce cost and improve productivity. Accessibility standards have been implemented in all products. CACDP have benefited from increased services for their customers, increased profitability, mature development and maintenance procedures, the introduction of a reuse programme for their future development and technical learning and training for their staff

Voyager spacecraft system, phase IA, TASK B - Preliminary design. Spacecraft functional design, volume A, book 2

Functional descriptions of subsystems for 1971 Voyager flight spacecraf

Study of one-man lunar flying vehicle. Volume 3 - Subsystem studies Final report

Criteria for optimum design of lunar flying vehicl