Potential for hardware-based techniques for reuse distance analysis

Reuse distance analysis, the prediction of how many distinct memory addresses will be accessed between two accesses to a given address, has been established as a useful technique in profile-based compiler optimization, but the cost of collecting the memory reuse profile has been prohibitive for some applications. In this report, we propose using the hardware monitoring facilities available in existing CPUs to gather an approximate reuse distance profile. The difficulties associated with this monitoring technique are discussed, most importantly that there is no obvious link between the reuse profile produced by hardware monitoring and the actual reuse behavior. Potential applications which would be made viable by a reliable hardware-based reuse distance analysis are identified

Space power distribution system technology. Volume 2: Autonomous power management

Electrical power subsystem requirements, power management system functional requirements, algorithms, power management subsystem, hardware development, and trade studies and analyses are discussed

Information management system study results. Volume 1: IMS study results

The information management system (IMS) special emphasis task was performed as an adjunct to the modular space station study, with the objective of providing extended depth of analysis and design in selected key areas of the information management system. Specific objectives included: (1) in-depth studies of IMS requirements and design approaches; (2) design and fabricate breadboard hardware for demonstration and verification of design concepts; (3) provide a technological base to identify potential design problems and influence long range planning (4) develop hardware and techniques to permit long duration, low cost, manned space operations; (5) support SR&T areas where techniques or equipment are considered inadequate; and (6) permit an overall understanding of the IMS as an integrated component of the space station

The application of computer aided draughting to mechanical engineering design

Imperial Users onl

Effective interprocess communication (IPC) in a real-time transputer network

The thesis describes the design and implementation of an interprocess communication (IPC) mechanism within a real-time distributed operating system kernel (RT-DOS) which is designed for a transputer-based network. The requirements of real-time operating systems are examined and existing design and implementation strategies are described. Particular attention is paid to one of the object-oriented techniques although it is concluded that these techniques are not feasible for the chosen implementation platform. Studies of a number of existing operating systems are reported. The choices for various aspects of operating system design and their influence on the IPC mechanism to be used are elucidated. The actual design choices are related to the real-time requirements and the implementation that has been adopted is described. [Continues.

Terrain Representation And Reasoning In Computer Generated Forces : A Survey Of Computer Generated Forces Systems And How They Represent And Reason About Terrain

Report on a survey of computer systems used to produce realistic or intelligent behavior by autonomous entities in simulation systems. In particular, it is concerned with the data structures used by computer generated forces systems to represent terrain and the algorithmic approaches used by those systems to reason about terrain

Space Generic Open Avionics Architecture (SGOAA) reference model technical guide

This report presents a full description of the Space Generic Open Avionics Architecture (SGOAA). The SGOAA consists of a generic system architecture for the entities in spacecraft avionics, a generic processing architecture, and a six class model of interfaces in a hardware/software system. The purpose of the SGOAA is to provide an umbrella set of requirements for applying the generic architecture interface model to the design of specific avionics hardware/software systems. The SGOAA defines a generic set of system interface points to facilitate identification of critical interfaces and establishes the requirements for applying appropriate low level detailed implementation standards to those interface points. The generic core avionics system and processing architecture models provided herein are robustly tailorable to specific system applications and provide a platform upon which the interface model is to be applied

A Generalized Data Extraction System for Vehicle Accident Information With Application to Selective Law Enforcement.

The purpose of this work is twofold: (1) to create a compre­hensive and complete data processing system specifically designed to permit efficient access to specific information contained in traffic accident information files, and (2) to demonstrate an appli: :ion of the system using a model developed for the optimal allocation of per­sonnel to reduce accidents by means of selective law enforcement. The Generalized Data Extraction System consists of two totally integrated programs: (1) the Accident Data File Creation Program, and (2) the Generalized Data Extraction Program. The Accident Data File Creation Program extracts information from a master accident data file, edits the information, and creates a reformatted permanent Accident Data File. The objective is to perform all those operations in file creation which would be time consuming and inefficient if performed during the search routines conducted during data extraction. The Generalized Data Extraction Program is specifically designed to interface directly with the Accident Data File and to be utilized by persons not trained in computer programming. In essence, this program permits the user to \u27ask the computer a question\u27 and obtain the answer in the form of three different formats the program is capable of generating. The three output formats the program is capable of generating are: (1) an accident swmnary report, (2) a high accident location report, and (3) a histogram depicting the accident experience for given stretches of roadway. To demonstrate an application of the Generalized Data Extrac­ tion System, a model is developed which provides for the optimal assignment of law enforcement personnel to maximize the reduction in the number of violations which have resulted in accidents subject to the constraints imposed by the scarcity of the resource and other relevant factors. Using a combination of concepts developed in this work and existing computer hardware/software systems, a total real-time program with the specific objective of optimally reducing accidents by timely and appropriate assignment of personnel has been discussed. The feasibility and efficiency of the Generalized Data Extrac­tion System and the concepts underlying the system have been successfully demonstrated. While the original system was designed to accommodate vehicle accident data, the underlying concepts extend far beyond this one specific application. Use of these concepts can provide the researcher or the manager with specific information neces­sary to analyze specific problems without resorting tu more costly and time consuming techniques

Decision Support Systems: Issues and Challenges; Proceedings of an International Task Force Meeting, June 23-25, 1980

This book reports on a three-day meeting on Decision Support Systems held at IIASA. IIASA's interest in sponsoring the meeting was spurred by several factors. First, the term DSS clearly is used in a wide range of contexts; we hoped to develop a deeper understanding of the term and the new field to which it refers. Second, we felt that ongoing work in the DSS field would be enhanced by interaction between professionals who had been working on such systems and people from fields that function as "resource disciplines" for DSS. Finally we wished to bring professionals from several nations together, from the east as well as the west, to share experiences and to assess the viability of the DSS concept in different cultures. The broad objectives set for this meeting were realized in a number of ways. Virtually all the participants testified that they had gained a deeper understanding of DSS, the role it can play in asssisting managers in organizations, and the need for further development in key areas

Telescience testbed pilot program, volume 3: Experiment summaries

Space Station Freedom and its associated labs, coupled with the availability of new computing and communications technologies, have the potential for significantly enhancing scientific research. A Telescience Testbed Pilot Program (TTPP), aimed at developing the experience base to deal with issues in the design of the future information system of the Space Station era. The testbeds represented four scientific disciplines (astronomy and astrophysics, earth science, life sciences, and microgravity sciences) and studied issues in payload design, operation, and data analysis. This volume, of a 3 volume set, which all contain the results of the TTPP, presents summaries of the experiments. This experiment involves the evaluation of the current Internet for the use of file and image transfer between SIRTF instrument teams. The main issue addressed was current network response times