In today's highly competitive global economy, information resources representing enterprise-wide information are essential to the survival of an organization. The development of and increase in the use of personal computers and data communication networks are supporting or, in many cases, replacing the traditional computer mainstay of corporations. The client/server model incorporates mainframe programming with desktop applications on personal computers. The aim of the research is to compile a technology model for the development of client/server software. A comprehensive overview of the individual components of the client/server system is given. The different methodologies, tools and techniques that can be used are reviewed, as well as client/server-specific design issues. The research is intended to create a road map in the form of a Technology Reference Model for Client/Server Software Development. / Computing / M. Sc. (Information Systems)

People work together to solve a wide variety of problems using different forms of cooperation for each class of problem. Modern technology is complex, and therefore it is unusual for an individual to attempt the development of a major project single-handedly. In an attempt to provide computer-based support for the problems that arise when two or more people attempt to cooperate to perform a task or solve a problem, the area of Computer Supported Cooperative Work (CSCW) becomes relevant. The software development process almost invariably involves cooperation that crosses group, professional, and subcultural boundaries. The complexity of software development demands that highly integrated groups of analysts, designers, and users are involved in the process. Many development activities may occur concurrently. The area of CSCW and advanced information technology, with its enormous capabilities for transmitting and storing information, holds considerable promise for the software development process. / Computing / M. Sc. (Information Systems)

Formal methods have been shown to be beneficial in increasing the quality of, and confidence in software systems. Despite the advantages of using formal methods in software development, the uptake in the commercial industry has been limited where the use of informal and semi-formal notations is favoured. To bridge the gap between the ease-of-use of semi-formal notation and correctness of formal methods, a number of approaches to the formalisation of informal and semi-formal notation have been researched and documented. Two of these approaches are discussed in this dissertation using a medium-sized case study to demonstrate the approaches. It was shown that each approach offered results that differed in terms of levels of abstraction, requisite knowledge of the formal target specification language and potential for automation. / Information Science / M.Sc.(Information Systems)

Hoare and He's Unifying Theories of Programming (UTP) provides a rich model of programs as relational predicates. This theory is intended to provide a single framework in which any programming paradigms, languages, and features, can be modelled, compared and contrasted. The UTP already has models for several programming formalisms, such as imperative programming, higher-order programming (e.g. programing with procedures), several styles of concurrent programming (or reactive systems), class-based object-orientation, and transaction processing. We believe that the UTP ought to be able to represent all significant computer programming language formalisms, in order for it to be considered a unifying theory. One gap in the UTP work is that of object-based object-orientation, such as that presented in Abadi and Cardelli's untyped object calculi (sigma-calculi). These sigma-calculi provide a prominent formalism of object-based object-oriented (OO) programs, which models programs as objects. We address this gap within this dissertation by presenting an embedding of an Abadi--Cardelli-style object calculus in the UTP. More formally, the thesis that his dissertation argues is that it is possible to provide an object-based object rientation to the UTP, with value- and reference-based objects, and a fully abstract model of references. We have made three contributions to our area of study: first, to extend the UTP with a notion of object-based object orientation, in contrast with the existing class-based models; second, to provide an alternative model of pointers (references) for the UTP that supports both value-based compound values (e.g. objects) and references (pointers), in contrast to existing UTP models with pointers that have reference-based compound values; and third, to model an Abadi-Cardelli notion of an object in the UTP, and thus demonstrate that it can unify this style of object formalism.

O desenvolvimento de sistemas de controle em plataformas de tempo real é uma tarefa que envolve Engenharia de Controle e Ciência da Computação. Nas últimas décadas, estas áreas se desenvolveram como áreas independentes. Este trabalho busca diminuir distância entre as áreas propondo a utilização de métodos de Engenharia de Software em uma fase de modelagem do software de controle. Uma das propostas apresentadas no trabalho é a utilização de frameworks orientados a objetos no processo de Rapid Control Prototyping (RCP) para substituir a geração automática de código, eliminar os problemas de integração com código legado e tornar o processo RCP mais interativo. Outra proposta é a utilização de plataformas para RCP composta por uma camada de hardware real, uma camada SOTR e uma camada de aplicação formada pelo framework para análise e desenvolvimento de sistemas de controle centralizado ou distribuído. / The development of real-time platform control systems is a task that involves Control Engineering and Computer Science. In the last decade, these areas have developed independent from each other. This paper seeks to decrease the distance between this areas, by proposing the use of Software Engineering methods in a software control modeling phase. One of the propositions in this paper is the use of object orientated frameworks in the Rapid Control Prototyping (RCP) process to substitute the automatic code generation, thus eliminating the problems with the legacy code and making the RCP process more interactive. Another proposition is the use of RCP directed platforms composed by a real hardware layer, a RTOS layer and an application layer formed by the framework for the analysis and development of the centralized or distributed control systems.

In dieser Dissertation, schaue ich auf objekt-orientierte Metamodellierung und wie sie verwendet werden kann, um Computersprachen zu beschreiben. Dabei, fokussiere ich mich nicht nur auf die Beschreibung von Sprachen, sondern auch auf die Verwendung von Sprachbeschreibungen zur automatischen Erzeugung von Sprachwerkzeugen aus Sprachbeschreibungen. Ich nutze die Idee von Metasprachen und Metawerkzeugen. Metasprachen werden verwendet um bestimmte Sprachaspekte, wie Notationen und Semantiken, zu beschreiben, und Metawerkzeuge werden verwendet um Sprachwerkzeuge wie Editoren und Interpreter aus entsprechenden Beschreibungen zu erzeugen. Diese Kombination von Beschreibung und automatischer Entwicklung von Werkzeugen ist als Domänenspezifische Modellierung (DSM) bekannt. Ich verwende DSM basierend auf objekt-orientierter Metamodellierung zur Beschreibung der wichtigen Aspekte ausführbarer Computersprachen. Ich untersuche existierende Metasprachen und Metawerkzeuge für die Beschreibung von Sprachvorkommen, ihrer konkreten Repräsentation und Semantik. Weiter, entwickle ich eine neue Plattform zur Beschreibung von Sprachen basierend auf dem CMOF-Modell der OMG MOF 2.x Empfehlungen. Ich entwickle eine Metasprache und Metawerkzeug für textuelle Notationen. Schlussendlich, entwickle ich eine graphische Metasprache und Metawerkzeug zur Beschreibung von operationaler Semantik von Computersprachen. Um die Anwendbarkeit der vorgestellten Techniken zu prüfen, nehme ich SDL, die Specification and Description Language, als einen Archetypen für textuell notierte Sprachen mit ausführbaren Instanzen. Für diesen Archetyp zeige ich, dass die präsentierten Metasprachen und Metawerkzeuge es erlauben solche Computersprachen zu beschreiben und automatisch Werkzeuge für diese Sprachen zu erzeugen. / In this thesis, I look into object-oriented meta-modelling and how it can be used to describe computer languages. Thereby, I do not only focus on describing languages, but also on utilising the language descriptions to automatically create language tools from language descriptions. I use the notion of meta-languages and meta-tools. Meta-languages are used to describe certain language aspects, such as notation or semantics, and meta-tools are used to create language tools, such as editors or interpreters, from corresponding descriptions. This combination of describing and automated development of tools is known as domain specific modelling (DSM). I use DSM based on object-oriented meta-modelling to describe all important aspects of executable computer languages. I look into existing meta-languages and meta-tools for describing language utterances, their concrete representation, and semantics. Furthermore, I develop a new platform to define languages based on the CMOF-model of the OMG MOF 2.x recommendations. I develop a meta-language and meta-tool for textual language notations. Finally, I develop a new graphical meta-language and meta-tool for describing the operational semantics of computer languages. To prove the applicability of the presented techniques, I take SDL, the Specification and Description Language, as an archetype for textually notated languages with executable instances. For this archetype, I show that the presented meta-languages and meta-tools allow to describe such computer languages and allow to automatically create tools for those languages.

Sistemas de Informação de Escritórios são tipos particulares de sistemas de informação. São sistemas sócio-técnicos, muito complexos, com grande influência humana. O tempo tem grande importância no tratamento das informações, tanto na representação de informações temporais explícitas como em restrições de ordem temporal e em características que são alteradas com a evolução da aplicação. Neste trabalho é apresentado um modelo de dados para ser utilizado como método de especificação de requisitos de sistemas de informação de escritórios. 0 desenvolvimento de especificações é uma tarefa bastante complexa, devendo possibilitar a representação de todas as características da aplicação, tanto as estáticas como as comportamentais. A especificação de uma aplicação geralmente é muito extensa, sendo dispendido um tempo considerável em sua elaboração. Um aspecto importante no desenvolvimento de especificações é a verificação da corretude destas, devido a complexidade que apresentam. Uma maneira de gerar especificações mais corretas e em menor espaço de tempo é através da reutilização de especificações anteriormente construídas e já validadas através de implementações. Neste trabalho optou-se por utilizar um modelo de dados orientado a objetos para especificar os sistemas de informação de escritórios. A utilização do paradigma de orientação a objetos na modelagem permite a definição de uma biblioteca de classes de objetos, classes estas identificadas em diversas especificações realizadas em um determinado domínio de aplicação. As classes constantes desta biblioteca podem ser reutilizadas de maneira bastante eficiente em especificações posteriores. A representação das características dinâmicas de uma aplicação, tais como a evolução dos objetos dentro do escritório, requer a possibilidade de representação de propriedades temporais. O modelo de dados utilizado na especificação deve permitir a representação de aspectos temporais tanto para definição de dados definidos em um domínio temporal como para representar a evolução dos valores assumidos pelos objetos durante sua existência. A possibilidade de representação dos aspectos temporais é um dos principais pontos desenvolvidos na elaboração do modelo de dados apresentado neste trabalho. O modelo apresentado denomina-se TF-ORM (Temporal Fuctionality in Objects with Roles Model), sendo uma extensão do modelo F-ORM (Functionality in Objects with Roles Model) [DEA 91a,b,c]. Foram incorporadas a este modelo os necessários aspectos temporais e foram ampliadas características básicas para captar melhor as particularidades do domínio de sistemas de informação de escritórios, principalmente no que à concerne representação de alguma parcela de trabalho humano. O modelo resultante, TF-ORM, um modelo de dados orientado a objetos, temporal, que utiliza o conceito de papéis para representar os diferentes comportamentos de um objeto. A possibilidade de recuperação de informações de um banco de dados que implemente o modelo de dados proposto foi também considerada. Neste trabalho é apresentada uma linguagem de recuperação de informações (linguagem de consulta) para o modelo de dados TF-ORM. Especial atenção é dada as consultas temporais. Como no modelo proposto são armazenados tanto o tempo de transação como o de validade, a linguagem de recuperação pode ser utilizada para recuperar informações referentes ao estado atual do banco de dados (informações atualmente válidas), a respeito de estados passados e futuros (informações válidas no passado e que serão válidas em estados futuros, de acordo com o atual conhecimento dos dados) e referentes a histórias passadas do banco de dados (informações que se acreditava como válidas em algum momento do passado). É apresentado em estudo de caso completo com o objetivo de validar o modelo de dados proposto e sua eficiência na especificação deste tipo de sistema de informação. O trabalho apresenta ainda a descrição de um ambiente de apoio a especificações que faz use de uma biblioteca de classes. Através deste ambiente, a especificação de uma aplicação é construída gradualmente, estando disponíveis opções de listagem das partes já definidas e de informações da biblioteca de classes para serem reutilizadas. As especificações geradas através deste ambiente apresentam pouca possibilidade de erro, uma vez que são efetuados vários procedimentos de verificação das informações fornecidas. / Office Information Systems constitute special kinds of information systems - very complex socio-technical systems, with large human influence. Time is very important in the information representation, not only for explicit temporal information but also for restrictions on temporal ordering of activities to be executed and to record the temporal evolution of property values. In this work a data model to be used as a requirement specification method for office infoimations systems is presented. Specification development is a complex task. All the possible characteristics of an application, static and behavioral, shall be represented. An applications' specification is usually not a trivial task, and a big amount of time is used to develop it. Specifications are usually very complex and the possibility of verifying the correctness is an important aspect to be considered. The reuse of specifications is a way to obtain a better rate of correctness spending less time, using parts of specifications that were already validated through previous implementations. An object-oriented data model is used in this work to specify office information systems. The use of the object-oriented paradigm allows the definition of a class library containing classes identified in several specifications constructed in a specific application domain. The reuse of classes of such a library in new specifications gives efficiency to the process. To represent the dynamic characteristics of an application, such as the documents evolution within the office, it is necessary to be able to represent temporal properties. The data model used in the specification shall allow the representation of these temporal aspects not only to model data defined in a temporal domain but also to represent the objects values evolution during an objects existence. The representaion of temporal aspects is one of the main issues developed in the data model defined in this work. The data model is called TF-ORM (Temporal Fuctionality in Objects with Roles Model), and is an extention to the F-ORM (Functionality in Objects with Roles Model) model [DEA 91 a,b,c]. To this model the necessary temporal aspects were added and the basic characteristics were enlarged to better capture the particular aspects of the office habilitation systems domain, specially concerning the representation of some parts of human work. The resulting model. TF-ORM, is an object-oriented temporal data model and uses the concept of roles to represent an objects different behaviors. The possibility of retrieving information from a database specified through this data model is also considered and a query language for the TF-ORM data model is presented. Special attention is given to the retrieval of temporal information. The TFORM data model stores both the transaction and the valid time associated to dynamic properties and allows the retrieving of information fettering the databases' actual state (actually valid information), information refering the databases' past and future states (valid information in the past and information that will be valid in the future according to the actual data knowledge) and information about the databases' past history (information that was believed to be true in some moment in the past). A complete case study is presented to validate the TF-ORM data model and its efficiency as a specification method for office information systems. An environment to support specifications using TF-ORM is described. This environment uses a class library. The use of this environment allows stepwise construction of a specification, with the access to listings of the already defined parts and to the information of the class library to be reused. The contructed specifications present a small rate of errors, due to several verification procedures embedded in the environment.

Formal methods have been shown to be beneficial in increasing the quality of, and confidence in software systems. Despite the advantages of using formal methods in software development, the uptake in the commercial industry has been limited where the use of informal and semi-formal notations is favoured. To bridge the gap between the ease-of-use of semi-formal notation and correctness of formal methods, a number of approaches to the formalisation of informal and semi-formal notation have been researched and documented. Two of these approaches are discussed in this dissertation using a medium-sized case study to demonstrate the approaches. It was shown that each approach offered results that differed in terms of levels of abstraction, requisite knowledge of the formal target specification language and potential for automation. / Information Science / M.Sc.(Information Systems)

In today's highly competitive global economy, information resources representing enterprise-wide information are essential to the survival of an organization. The development of and increase in the use of personal computers and data communication networks are supporting or, in many cases, replacing the traditional computer mainstay of corporations. The client/server model incorporates mainframe programming with desktop applications on personal computers. The aim of the research is to compile a technology model for the development of client/server software. A comprehensive overview of the individual components of the client/server system is given. The different methodologies, tools and techniques that can be used are reviewed, as well as client/server-specific design issues. The research is intended to create a road map in the form of a Technology Reference Model for Client/Server Software Development. / Computing / M. Sc. (Information Systems)

People work together to solve a wide variety of problems using different forms of cooperation for each class of problem. Modern technology is complex, and therefore it is unusual for an individual to attempt the development of a major project single-handedly. In an attempt to provide computer-based support for the problems that arise when two or more people attempt to cooperate to perform a task or solve a problem, the area of Computer Supported Cooperative Work (CSCW) becomes relevant. The software development process almost invariably involves cooperation that crosses group, professional, and subcultural boundaries. The complexity of software development demands that highly integrated groups of analysts, designers, and users are involved in the process. Many development activities may occur concurrently. The area of CSCW and advanced information technology, with its enormous capabilities for transmitting and storing information, holds considerable promise for the software development process. / Computing / M. Sc. (Information Systems)