4,079 research outputs found

    Navigating global-local tensions in accountability/autonomy policies: Comparative case studies in 'Asian' universities

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    The twin policy domains of accountability and autonomy have featured in recent education reforms in many countries, signalling new relationships between governments and educational institutions. Despite different national and localised contexts, a number of common 'global' trends have been identified. However, simultaneously context-specific differences are also evident. For us, the concept of 'globalisation', when it implies policy homogenisation, is too blunt an instrument to critically analyse these major reforms. We would argue that there are still too few studies on globalisation processes grounded in detailed examinations of particular historical times and geographical spaces. Our research is located within the tensions between global commonalities and localised differences. This paper reports research on changing accountability and autonomy in higher education in three 'Asian' countries. Empirical data has been collected in the People's Republic of China, Hong Kong and Singapore in an attempt to begin to redress a 'Western' hegemony in such research. Within each national context two different types of universities became case study sites for the analysis of both commonalities and differences in accountability and autonomy policies and practices. The current paper focuses in particular on the conceptual and methodological framings of the research and presents some preliminary findings

    Knowledge-based design support and inductive learning

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    Designing and learning are closely related activities in that design as an ill-structure problem involves identifying the problem of the design as well as finding its solutions. A knowledge-based design support system should support learning by capturing and reusing design knowledge. This thesis addresses two fundamental problems in computational support to design activities: the development of an intelligent design support system architecture and the integration of inductive learning techniques in this architecture.This research is motivated by the belief that (1) the early stage of the design process can be modelled as an incremental learning process in which the structure of a design problem or the product data model of an artefact is developed using inductive learning techniques, and (2) the capability of a knowledge-based design support system can be enhanced by accumulating and storing reusable design product and process information.In order to incorporate inductive learning techniques into a knowledge-based design model and an integrated knowledge-based design support system architecture, the computational techniques for developing a knowledge-based design support system architecture and the role of inductive learning in Al-based design are investigated. This investigation gives a background to the development of an incremental learning model for design suitable for a class of design tasks whose structures are not well known initially.This incremental learning model for design is used as a basis to develop a knowledge-based design support system architecture that can be used as a kernel for knowledge-based design applications. This architecture integrates a number of computational techniques to support the representation and reasoning of design knowledge. In particular, it integrates a blackboard control system with an assumption-based truth maintenance system in an object-oriented environment to support the exploration of multiple design solutions by supporting the exploration and management of design contexts.As an integral part of this knowledge-based design support architecture, a design concept learning system utilising a number of unsupervised inductive learning techniques is developed. This design concept learning system combines concept formation techniques with design heuristics as background knowledge to build a design concept tree from raw data or past design examples. The design concept tree is used as a conceptual structure for the exploration of new designs.The effectiveness of this knowledge-based design support architecture and the design concept learning system is demonstrated through a realistic design domain, the design of small-molecule drugs one of the key tasks of which is to identify a pharmacophore description (the structure of a design problem) from known molecule examples.In this thesis, knowledge-based design and inductive learning techniques are first reviewed. Based on this review, an incremental learning model and an integrated architecture for intelligent design support are presented. The implementation of this architecture and a design concept learning system is then described. The application of the architecture and the design concept learning system in the domain of small-molecule drug design is then discussed. The evaluation of the architecture and the design concept learning system within and beyond this particular domain, and future research directions are finally discussed

    Management of conflict for preliminary engineering design tasks

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    Much of preliminary engineering design is a constraint-driven non-monotonic exploration process. Initial decisions are made when information is incomplete and many goals are contradictory. Such conditions are present regardless of whether one or several designers contribute to designs. This paper presents an approach for supporting decisions in situations of incomplete and conflicting knowledge. In particular, we use assumptions and conflict management to achieve efficient search in contexts where little reliable information exists. A knowledge representation, containing a semantic differentiation between two types of assumptions, is used within a computational model based on the dynamic constraint satisfaction paradigm. Conflict management strategies consist of three generic mechanisms adapted to the type of constraints involved. These strategies may be refined through consideration of variable importance, context, and design inerti

    Intelligent systems in manufacturing: current developments and future prospects

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    Global competition and rapidly changing customer requirements are demanding increasing changes in manufacturing environments. Enterprises are required to constantly redesign their products and continuously reconfigure their manufacturing systems. Traditional approaches to manufacturing systems do not fully satisfy this new situation. Many authors have proposed that artificial intelligence will bring the flexibility and efficiency needed by manufacturing systems. This paper is a review of artificial intelligence techniques used in manufacturing systems. The paper first defines the components of a simplified intelligent manufacturing systems (IMS), the different Artificial Intelligence (AI) techniques to be considered and then shows how these AI techniques are used for the components of IMS

    Multi-Agent Systems

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    A multi-agent system (MAS) is a system composed of multiple interacting intelligent agents. Multi-agent systems can be used to solve problems which are difficult or impossible for an individual agent or monolithic system to solve. Agent systems are open and extensible systems that allow for the deployment of autonomous and proactive software components. Multi-agent systems have been brought up and used in several application domains

    A manufacturing model to support data-driven applications for design and manufacture

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    This thesis is primarily concerned with conceptual work on the Manufacturing Model. The Manufacturing Model is an information model which describes the manufacturing capability of an enterprise. To achieve general applicability, the model consists of the entities that are relevant and important for any type of manufacturing firm, namely: manufacturing resources (e.g. machines, tools, fixtures, machining cells, operators, etc.), manufacturing processes (e.g. injection moulding, machining processes, etc.) and manufacturing strategies (e.g. how these resources and processes are used and organized). The Manufacturing Model is a four level model based on a de—facto standard (i.e. Factory, Shop, Cell, Station) which represents the functionality of the manufacturing facility of any firm. In the course of the research, the concept of data—driven applications has emerged in response to the need of integrated and flexible computer environments for the support of design and manufacturing activities. These data—driven applications require the use of different information models to capture and represent the company's information and knowledge. One of these information models is the Manufacturing Model. The value of this research work is highlighted by the use of two case studies, one related with the representation of a single machining station, and the other, the representation of a multi-cellular manufacturing facility of a high performance company

    Real-time communications over switched Ethernet supporting dynamic QoS management

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    Doutoramento em Engenharia InformĂĄticaDurante a Ășltima dĂ©cada temos assistido a um crescente aumento na utilização de sistemas embutidos para suporte ao controlo de processos, de sistemas robĂłticos, de sistemas de transportes e veĂ­culos e atĂ© de sistemas domĂłticos e eletrodomĂ©sticos. Muitas destas aplicaçÔes sĂŁo crĂ­ticas em termos de segurança de pessoas e bens e requerem um alto nĂ­vel de determinismo com respeito aos instantes de execução das respectivas tarefas. AlĂ©m disso, a implantação destes sistemas pode estar sujeita a limitaçÔes estruturais, exigindo ou beneficiando de uma configuração distribuĂ­da, com vĂĄrios subsistemas computacionais espacialmente separados. Estes subsistemas, apesar de espacialmente separados, sĂŁo cooperativos e dependem de uma infraestrutura de comunicação para atingir os objectivos da aplicação e, por consequĂȘncia, tambĂ©m as transacçÔes efectuadas nesta infraestrutura estĂŁo sujeitas Ă s restriçÔes temporais definidas pela aplicação. As aplicaçÔes que executam nestes sistemas distribuĂ­dos, chamados networked embedded systems (NES), podem ser altamente complexas e heterogĂ©neas, envolvendo diferentes tipos de interacçÔes com diferentes requisitos e propriedades. Um exemplo desta heterogeneidade Ă© o modelo de activação da comunicação entre os subsistemas que pode ser desencadeada periodicamente de acordo com uma base de tempo global (time-triggered), como sejam os fluxos de sistemas de controlo distribuĂ­do, ou ainda ser desencadeada como consequĂȘncia de eventos assĂ­ncronos da aplicação (event-triggered). Independentemente das caracterĂ­sticas do trĂĄfego ou do seu modelo de activação, Ă© de extrema importĂąncia que a plataforma de comunicaçÔes disponibilize as garantias de cumprimento dos requisitos da aplicação ao mesmo tempo que proporciona uma integração simples dos vĂĄrios tipos de trĂĄfego. Uma outra propriedade que estĂĄ a emergir e a ganhar importĂąncia no seio dos NES Ă© a flexibilidade. Esta propiedade Ă© realçada pela necessidade de reduzir os custos de instalação, manutenção e operação dos sistemas. Neste sentido, o sistema Ă© dotado da capacidade para adaptar o serviço fornecido Ă  aplicação aos respectivos requisitos instantĂąneos, acompanhando a evolução do sistema e proporcionando uma melhor e mais racional utilização dos recursos disponĂ­veis. No entanto, maior flexibilidade operacional Ă© igualmente sinĂłnimo de maior complexidade derivada da necessidade de efectuar a alocação dinĂąmica dos recursos, acabando tambĂ©m por consumir recursos adicionais no sistema. A possibilidade de modificar dinĂąmicamente as caracteristicas do sistema tambĂ©m acarreta uma maior complexidade na fase de desenho e especificação. O aumento do nĂșmero de graus de liberdade suportados faz aumentar o espaço de estados do sistema, dificultando a uma pre-anĂĄlise. No sentido de conter o aumento de complexidade sĂŁo necessĂĄrios modelos que representem a dinĂąmica do sistema e proporcionem uma gestĂŁo optimizada e justa dos recursos com base em parĂąmetros de qualidade de serviço (QdS). É nossa tese que as propriedades de flexibilidade, pontualidade e gestĂŁo dinĂąmica de QdS podem ser integradas numa rede switched Ethernet (SE), tirando partido do baixo custo, alta largura de banda e fĂĄcil implantação. Nesta dissertação Ă© proposto um protocolo, Flexible Time-Triggered communication over Switched Ethernet (FTT-SE), que suporta as propriedades desejadas e que ultrapassa as limitaçÔes das redes SE para aplicaçÔes de tempo-real tais como a utilização de filas FIFO, a existĂȘncia de poucos nĂ­veis de prioridade e a pouca capacidade de gestĂŁo individualizada dos fluxos. O protocolo baseia-se no paradigma FTT, que genericamente define a arquitectura de uma pilha protocolar sobre o acesso ao meio de uma rede partilhada, impondo desta forma determinismo temporal, juntamente com a capacidade para reconfiguração e adaptação dinĂąmica da rede. SĂŁo ainda apresentados vĂĄrios modelos de distribuição da largura de banda da rede de acordo com o nĂ­vel de QdS especificado por cada serviço utilizador da rede. Esta dissertação expĂ”e a motivação para a criação do protocolo FTT-SE, apresenta uma descrição do mesmo, bem como a anĂĄlise de algumas das suas propiedades mais relevantes. SĂŁo ainda apresentados e comparados modelos de distribuição da QdS. Finalmente, sĂŁo apresentados dois casos de aplicaçÔes que sustentam a validade da tese acima mencionada.During the last decade we have witnessed a massive deployment of embedded systems on a wide applications range, from industrial automation to process control, avionics, cars or even robotics. Many of these applications have an inherently high level of criticality, having to perform tasks within tight temporal constraints. Additionally, the configuration of such systems is often distributed, with several computing nodes that rely on a communication infrastructure to cooperate and achieve the application global goals. Therefore, the communications are also subject to the same temporal constraints set by the application requirements. Many applications relying on such networked embedded systems (NES) are complex and heterogeneous, comprehending different activities with different requirements and properties. For example, the communication between subsystems may follow a strict temporal synchronization with respect to a global time-base (time-triggered), like in a distributed feedback control loop, or it may be issued asynchronously upon the occurrence of events (eventtriggered). Regardless of the traffic characteristics and its activation model, it is of paramount importance having a communication framework that provides seamless integration of heterogeneous traffic sources while guaranteeing the application requirements. Another property that has been emerging as important for NES design and operation is flexibility. The need to reduce installation and operational costs, while facilitating maintenance is promoting a more rational use of the available resources at run-time, exploring the ability to tune service parameters as the system evolves. However, such operational flexibility comes with the cost of increasing the complexity of the system to handle the dynamic resource management, which on the other hand demands the allocation of additional system resources. Moreover, the capacity to dynamically modify the system properties also causes a higher complexity when designing and specifying the system, since the operational state-space increases with the degrees of flexibility of the system. Therefore, in order to bound this complexity appropriate operational models are needed to handle the system dynamics and carry on an efficient and fair resource management strategy based on quality of service (QoS) metrics. This thesis states that the properties of flexibility and timeliness as needed for dynamic QoS management can be provided to switched Ethernet based systems. Switched Ethernet, although initially designed for general purpose Internet access and file transfers, is becoming widely used in NES-based applications. However, COTS switched Ethernet is insufficient regarding the needs for real-time predictability and for supporting the aforementioned properties due the use of FIFO queues too few priority levels and for stream-level management capabilities. In this dissertation we propose a protocol to overcome those limitations, namely the Flexible Time-Triggered communication over Switched Ethernet (FTT-SE). The protocol is based on the FTT paradigm that generically defines a protocol architecture suitable to enforce real-time determinism on a communication network supporting the desired flexibility properties. This dissertation addresses the motivation for FTT-SE, describing the protocol as well as its schedulability analysis. It additionally covers the resource distribution topic, where several distribution models are proposed to manage the resource capacity among the competing services and while considering the QoS level requirements of each service. A couple of application cases are shown that support the aforementioned thesis

    Trust engineering framework for software services

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    La presente tesis presenta un marco de trabajo que abarca distintas fases del ciclo de vida de los servicios software y que permite a ingenieros de requisitos, diseñadores y desarrolladores la integración en dichos servicios de modelos de confianza y reputación. En la fase de planificación, proponemos una metodología para evaluar la confianza en proveedores de Cloud antes de decidir si el sistema, o parte de él, se traslada al mismo. En la fase de anålisis, ofrecemos una notación para la captura y representación de requisitos de confianza y reputación. Asimismo en esta misma fase, desarrollamos una metodología que permite detectar amenazas internas en un sistema a través de anålisis de relaciones de confianza. Para la fase de diseño, proponemos un perfil UML que permite la especificación de modelos de confianza y reputación, lo cual facilita la siguiente fase de implementación, para la que desarrollamos un marco de trabajo que los desarrolladores pueden usar para implementar una amplia variedad de modelos de confianza y reputación. Finalmente, para la fase de verificación en tiempo de ejecución, presentamos un marco de trabajo desarrollado sobre una plataforma de sistemas auto-adaptativos que implementa el paradigma de modelos en tiempo de ejecución. Con dicho marco de trabajo, hacemos posible que los desarrolladores puedan implementar modelos de confianza y reputación, y que puedan usar la información proporcionada por dichos modelos para especificar políticas de reconfiguración en tiempo de ejecución. Esto permite que el sistema se adapte de forma que se mantengan niveles tolerables de confianza y reputación en los componentes de los que consiste. Todo los trabajos anteriores se apoyan sobre un marco conceptual que captura y relaciona entre sí las nociones mås relevantes en los dominios de la confianza y la reputación
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