An accurate prefetching policy for object oriented systems

PhD ThesisIn the latest high-performance computers, there is a growing requirement for accurate prefetching(AP) methodologies for advanced object management schemes in virtual memory and migration systems. The major issue for achieving this goal is that of finding a simple way of accurately predicting the objects that will be referenced in the near future and to group them so as to allow them to be fetched same time. The basic notion of AP involves building a relationship for logically grouping related objects and prefetching them, rather than using their physical grouping and it relies on demand fetching such as is done in existing restructuring or grouping schemes. By this, AP tries to overcome some of the shortcomings posed by physical grouping methods. Prefetching also makes use of the properties of object oriented languages to build inter and intra object relationships as a means of logical grouping. This thesis describes how this relationship can be established at compile time and how it can be used for accurate object prefetching in virtual memory systems. In addition, AP performs control flow and data dependency analysis to reinforce the relationships and to find the dependencies of a program. The user program is decomposed into prefetching blocks which contain all the information needed for block prefetching such as long branches and function calls at major branch points. The proposed prefetching scheme is implemented by extending a C++ compiler and evaluated on a virtual memory simulator. The results show a significant reduction both in the number of page fault and memory pollution. In particular, AP can suppress many page faults that occur during transition phases which are unmanageable by other ways of fetching. AP can be applied to a local and distributed virtual memory system so as to reduce the fault rate by fetching groups of objects at the same time and consequently lessening operating system overheads.British Counci

GRASP/Ada (Graphical Representations of Algorithms, Structures, and Processes for Ada): The development of a program analysis environment for Ada. Reverse engineering tools for Ada, task 1, phase 2

The study, formulation, and generation of structures for Ada (GRASP/Ada) are discussed in this second phase report of a three phase effort. Various graphical representations that can be extracted or generated from source code are described and categorized with focus on reverse engineering. The overall goal is to provide the foundation for a CASE (computer-aided software design) environment in which reverse engineering and forward engineering (development) are tightly coupled. Emphasis is on a subset of architectural diagrams that can be generated automatically from source code with the control structure diagram (CSD) included for completeness

Evaluating the adoption of enterprise application integration in multinational organisations

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.A review of normative literature, in the field of Information Systems (IS) integration, indicates that traditional approaches to applications integration have failed to result in flexible and maintainable IT infrastructures. In addressing this issue, a new technology called Enterprise Application Integration (EAI) has emerged and addresses most of integration problems by resulting in the development of reusable and manageable IT infrastructures. Enterprise application integration is a new research area with many research issues needing to be investigated. At this end, EAI adoption has not efficiently studied with organisations and researchers needing to understand and analyse EAI adoption. This work examines the introduction of enterprise application integration in multinational organisations and proposes a novel model for its adoption. The model is based on a comprehensive set of factors that influence the introduction of EAI in organisations. Since there is an absence of theoretical models for EAI adoption, the proposed model adapts factors that influence the adoption of other integration technologies such as Electronic Data Interchange (EDT). Additional factors like an evaluation framework that supports decision making have been considered by the author as factors that influence EAI adoption. In moving from the conceptual to the empirical, the work is based on a qualitative case study approach to examine the concepts of the proposed model for the adoption of EAI. In doing so, two case studies were conducted at multinational organisations and presented and analysed. However, during the empirical research complementary factors also emerged, which resulted in modifications being made to the previously presented conceptual model. In interpreting from empirical data, it appears that ten main factors influence the adoption of EAT namely: (a) benefits; (b) barriers; (c) costs; (d) internal pressures; (e) external pressures; (f) IT infrastructure; (g) IT sophistication; (h) an evaluation framework for the assessment of integration technologies; (i) evaluation framework for the assessment of EAT packages and, (j) support. The proposed model makes novel contribution at two levels. First, at the conceptual level, as it incorporates factors identified separately in previous studies as influencing adoption of other integration technologies. These factors are used for the development of a consistent model for the adoption and evaluation of EAT. Secondly, the concepts of the proposed model can be used for the adoption of inter-organisational information systems. The proposed model can be used as a decision-making tool to support management when taking decisions regarding the adoption of EAI. Additionally, it can be used by researchers to analyse and understand the adoption of application integration.This work is funded by the Brunel University Department of Information Systems and Computing

Readiness For Shifting From A Traditional Higher Education Learning System To An E-Learning System: A Case Study From The Sultanate Of Oman

The Ministry of Higher Education in the Sultanate of Oman initiated recently a restructuring program for the General Directorate Colleges of Education aiming to replace the existing six colleges with more applied and highly IT assisted institutions. A particular emphasis is directed towards improving the learning methods by developing and implementing a unified Learning Management System (LMS), which will serve the new form of these colleges. Such system is particularly intended to improve the e-learning skills in the six Colleges of Education. Each college has a Learning Resource Center (LRC) that provides IT services for about 1500 students and 150 staff members. During the past few years, the LRC at Nizwa College of Education (NCoE) has exerted many efforts in upgrading such services to the benefit of the college community. The discussion in this paper will be based on Nizwa LRC as an example, reflecting uniformity among the six colleges of education. This paper analyzes the readiness of the current learning system for the gradual shifting to a more IT assisted teaching system. First, the paper describes the evolution of the Intranet and Internet services in the college. Second, the steps realized in expanding and upgrading IT are described. Third, an evaluation of the available services and users is presented. This is supported by the analysis of the experimental implementation of an open source LMS, the "Modular Object-Oriented Dynamic Learning Environment" (Moodle) to assess the effectiveness of Moodle as a learning facilitator. Finally, recommendations on how to improve the outsourcing of these services are given. Aspects of the services provided by the LRC will be discussed through different users’ perspectives

Simulation modelling and visualisation: toolkits for building artificial worlds

Simulations users at all levels make heavy use of compute resources to drive computational simulations for greatly varying applications areas of research using different simulation paradigms. Simulations are implemented in many software forms, ranging from highly standardised and general models that run in proprietary software packages to ad hoc hand-crafted simulations codes for very specific applications. Visualisation of the workings or results of a simulation is another highly valuable capability for simulation developers and practitioners. There are many different software libraries and methods available for creating a visualisation layer for simulations, and it is often a difficult and time-consuming process to assemble a toolkit of these libraries and other resources that best suits a particular simulation model. We present here a break-down of the main simulation paradigms, and discuss differing toolkits and approaches that different researchers have taken to tackle coupled simulation and visualisation in each paradigm

New Trends in Development of Services in the Modern Economy

The services sector strategic development unites a multitude of economic and managerial aspects and is one of the most important problems of economic management. Many researches devoted to this industry study are available. Most of them are performed in the traditional aspect of the voluminous calendar approach to strategic management, characteristic of the national scientific school. Such an approach seems archaic, forming false strategic benchmarks. The services sector is of special scientific interest in this context due to the fact that the social production structure to the services development model attraction in many countries suggests transition to postindustrial economy type where the services sector is a system-supporting sector of the economy. Actively influencing the economy, the services sector in the developed countries dominates in the GDP formation, primary capital accumulation, labor, households final consumption and, finally, citizens comfort of living. However, a clear understanding of the services sector as a hyper-sector permeating all spheres of human activity has not yet been fully developed, although interest in this issue continues to grow among many authors. Target of strategic management of the industry development setting requires substantive content and the services sector target value assessment

Advancing automation and robotics technology for the Space Station Freedom and for the U.S. economy

In April 1985, as required by Public Law 98-371, the NASA Advanced Technology Advisory Committee (ATAC) reported to Congress the results of its studies on advanced automation and robotics technology for use on Space Station Freedom. This material was documented in the initial report (NASA Technical Memorandum 87566). A further requirement of the law was that ATAC follow NASA's progress in this area and report to Congress semiannually. This report is the fifteenth in a series of progress updates and covers the period between 27 Feb. - 17 Sep. 1992. The progress made by Levels 1, 2, and 3 of the Space Station Freedom in developing and applying advanced automation and robotics technology is described. Emphasis was placed upon the Space Station Freedom program responses to specific recommendations made in ATAC Progress Report 14. Assessments are presented for these and other areas as they apply to the advancement of automation and robotics technology for Space Station Freedom