Thesis (Ph. D.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 191-197). Also available via the World Wide Web.

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaf 59). Also available via the Internet.

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[pt] Esta dissertação descreve a concepção de uma arquitetura de computador com conjunto reduzido de instruções, otimizada para uso com linguagens de programação calcadas no paradigma da orientação a objetos. Buscou-se aliar as mais modernas tecnologias utilizadas nas arquiteturas dos processadores de última geração a um conjunto de características que, empregadas corretamente e em união com ferrramentas de programação adequadas, visam reduzir o impacto no desempenho à que normalmente são submetidos os sistemas baseados em objetos. Aparte da linha seguida pela Comunidade Científica nesta área, não se buscou uma nova estrutura de armazenamento ou de processamentos dos dados. Ao contrário, desde o início foi objetivo utilizar ao máximo a experiência acumulada com pouco mais de duas décadas de microprocessadores para se projetar um arquitetura genérica, porém com algumas caracterísitcas especiais. / [en] This dissertation describes the conception of a reduced instruction set computer architecture, optimized for the use with programming languages based on the object orientation paradigm. The aim was to bond the most recent technologies used in the last generation processors to a set of characteristics that, when used correctly and in conjunction with adequate programming tools, tend to reduce the performance impact that are usually submitted the systems based upon objects. Apart from the line followed by the Scientific Community in this area, a new storage or data processing structure was not aimed. On the contrary, from the beginning it has been the target to use the experience accumulated in a little more than two decades of microprocessors at most, to design a generic architecture, but with a few special characteristics.

M.Com. (Computer Auditing) / During the last few decades the hardware of a computer system has undergone repeated revolutions. On the other hand the software development process has remained largely unchanged. The advent of the Information Age has, however, necessitated major improvements in the software development process. Object-Orientated Programming is seen as the vehicle by which this can be achieved. The use of object-orientation involves the auditor in two major areas. Firstly, the auditor may be involved in advising as to which systems engineering process to use and secondly, to assess the influence of the systems engineering process on the control environment of the client's computer system. In this dissertation, both the use of object orientation as a systems engineering methodology and the implications of this methodology on the control environment are discussed. Object-Orientated Programming can be broken down into the three main features, encapsulation, inheritance and interfaces. Encapsulation implies that both the data and processes that are permissible on that data, should be encapsulated as a single entity, known as an object. Inheritance on the other hand can be thought of as a specialisation of objects, to form a hierarchy of objects. Inheritance is, therefore, a way of sharing information between objects but with additional features to change or add certain attributes or methods of other objects. The external powers of an object are completely circumscribed by message passing. The only way in which an object can be addressed is to send a message to the object. This is done by the specific interfaces between the objects.

M.Sc. / In a society that is becoming increasingly reliant on information, it is necessary for information to be stored efficiently and safely. Database technology is used to store large chunks of information efficiently, while database security is concerned with storing information securely. More complex computer applications (CAD/CAM, multimedia and Groupware) led to then development of object-oriented programming, with object-oriented databases following shortly after. Object-oriented databases store the data of object-oriented systems efficiently and permanently. They provide a rich set of semantic structures that allows them to be used in applications where other database models are simply inadequate. In federations consisting of several interconnected databases, security plays a vital role in the proper management of information. This work describes a Secure Distributed Object Environment (SDOE) infrastructure. It is designed to be implementation-oriented, on which strict theoretic prototypes such as SPOP (Selfprotecting Object Prototype) can be built. SPOP is a prototype of a secure object-oriented database and is based on the SPO database model of Olivier. To describe federated database architectures (used by SDOE and SPOP), it is necessary to understand the architecture of federated database systems. Reference architectures for federated database systems are discussed first and a comparison is drawn between two prominent reference architectures. We proposed a generalised reference architecture based on these two architectures. created in order to make the use of object-oriented programming in a distributed environment as problem free as possible. A marshal buffer structure will be discussed thirdly. The latter structure is used to contain procedure parameters during an RPC (Remote Procedure Call). Fourthly, the communications infrastructure necessary to support higher-level services is discussed. The infrastructure is implemented in Linux (a UNIX variant), and this approach has provided several interesting challenges. The fifth discussion will deal with the requirements for a name service. A name service is necessary if objects were to be used transparently (without reference to their current locations in the federation).

Most current approaches to Information Systems Development (ISD) tend to derive from past experience and practice, rules of thumb and technology trends. The lack of theoretical foundations hinders the systematic development and evaluation of new ISD methodologies. The research undertaken in this thesis addresses this issue by proposing a formal, theory-based model, Ontology/Object-Based Conceptual Modelling (OBCM), for conceptually representing IS applications. The formalism is novel in that it is grounded in first principles derived from metaphysics, in particular the system of Ontology developed by Mario Bunge. Underlying this approach is the premise that an Information System is a model of reality and that model should be therefore rooted in a theory of reality, ie. a metaphysics. As a result, basic assumptions in reality such as thing, substance, property, attribute, time, state and change are explicitly and rigorously addressed. OBCM features an ontologically well-defined construct, "object", which is used to directly represent entities in reality, thus lending theoretical credence to the so-called object-oriented paradigm found in recent programming languages and databases. In addition, the thesis presents a framework, Ontology/Object-Based Information System (OBIS), for systems implementation based on this model. This framework directly implements the object construct so that it can be immediately utilized by the information systems user in a "direct manipulation" style of end-user interaction. Further, OBIS strives for a single, homogeneous concept of system operation drawn from ontology rather than in terms of IS or computing technology. In principle, this one concept can be applied to any object in the IS, this simplifying the understanding and use of the Information System. In this way, the model attempts to unify the analysis, implementation and user-interface aspects of Information Systems Development, thereby reducing the so-called "semantic gap" which has often been observed between the reality of the application and its final implementation in an IS. A "proof of concept" prototype is described which illustrates the main principles and explores practical applications of the proposed model. This prototype is implemented as a single, stand-alone "shell" which can be used to support a wide variety of applications as well as providing the basis of a rapid prototyping or CASE tool. The prototype is used to implement sample problems including the well-known IFIP Working Conference problem, thus demonstrating the feasibility of the overall approach. / Business, Sauder School of / Graduate

Objects are entities which encapsulate data and those operations which manipulate the data. A distributed, object-based programming system (or DOBPS) is a distributed operating system which has been designed to support an object-based programming language and, in particular, an object abstraction. DOBPSs have the benefits of simplifying program construction and improving the performance of programs by providing efficient, system-level support for the abstractions used by the language. Many DOBPSs also permit hardware and software failures to be tolerated. This thesis introduces a definition for the term "distributed, object-based programming system" and identifies the features, that are related to objects, which are required by an operating system of a DOBPS. A classification scheme is presented that categorizes and characterizes these features to permit a number of implementation techniques to be easily examined, compared, and contrasted. / Science, Faculty of / Computer Science, Department of / Graduate

This project was undertaken as part of an effort to explore the design of object -oriented systems that are distributed, concurrent, real-time and/or embedded in nature. This work seeks to integrate the concurrency features of the actor model in a distributed, object oriented environment, ESP. The integrated system, called the Actor Systems Platform (ASP), provides a platform for designing concurrent, distributed applications. The actor model provides a mechanism for expressing the inherent concurrency in an application. The concurrency in the application can be exploited by the distributed features available in ESP. <p>The actor abstraction in ASP is provided by a application-level class hierarchy in ESP. The message passing semantics of the actor model are implemented by using special operator overloading in C++. Cboxes are implemented to provide a synchronization mechanism and a means of returning replies. In a concurrent system, simultaneous execution of an object's methods can cause its state to be inconsistent. This is prevented by providing a method locking mechanism using behavior sets. While integrating the concurrency features of the actor model in an object-oriented environment, differences were encountered in determining the invocation semantics of the actor model and those of inherited methods. The problem is investigated and a taxonomy of solutions is presented. / Master of Science

Master of Information Systems