4,079 research outputs found
Navigating global-local tensions in accountability/autonomy policies: Comparative case studies in 'Asian' universities
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
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
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
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
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
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An investigation of constraint-based risk management for collaborative design
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.In the context of internationally challenging economic, design has been regarded as a key factor in assisting design and manufacturing companies to survive. By using up-to-date computer-supported technology, the global design collaboration based on multidisciplinary and distributed environment is becoming a mainstream to new product development (NPD). However, during the process of collaborative design, risk is rarely mentioned. In particular, due to the complexity of design process and lack of efficient design decision-making, there have been some design collaboration failures across multiple companies. Some design projects cannot deliver the benefits as companies have expected through the collaboration. Moreover, a number of stakeholders, managers and designers expressed their disappointment at not seeing the projected savings in cost and time, which critically discredited the value of design collaboration.
Many studies in academia and commercial cases have suggested that risk assessment can be applied as an effective means in the realm of design. Nevertheless, few of them conducted risk management research associated with design constraints under a collaborative environment from both theoretical and practical perspectives. In current risk practice, many risk practitioners simply report key risks to their management teams and no further analysis, which might subsequently result in confusion with excessive discussions. Consequently, to prevent the failure of design collaboration and perform a satisfactory risk assessment, it is important to perform risk management with an upstream perspective and at an operational level.
An approach, called constraint-based design risk management (DRM) where a conceptual framework has been proposed on the basis of collaborative design features, risk management process and Theory of Constraints (TOC). Moreover, a DRM matrix has been developed to map, measure and mitigate collaborative design risk through evaluating the critical design constraints, and then specified design risk variables in the light of risk criteria. Design constraints are quantitative parameters that frequently affect main design processes and decisions. The combination of design constraints and risk criteria can be accessible and applicable by designers and design mangers. In addition, a Bayesian weighting method based on Bayesian theorem has been developed to measure collaborative design risk in a more efficient manner. Ultimately, a DRM tool has been created as a simulated scenario prototype, which incorporated with three case-study evaluations, to demonstrate the importance and effectiveness of using TOC and risk theory in the realm of design collaboration
A manufacturing model to support data-driven applications for design and manufacture
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 deâfacto 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 dataâdriven applications has emerged in
response to the need of integrated and flexible computer environments for the
support of design and manufacturing activities. These dataâdriven 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
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. Além 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,
também as transacçÔes efectuadas nesta infraestrutura estão sujeitas à s
restriçÔes temporais definidas pela aplicação.
As aplicaçÔes que executam nestes sistemas distribuĂdos, chamados
networked embedded systems (NES), podem ser altamente complexas e
heterogéneas, 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, é de extrema importùncia 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 é a flexibilidade. Esta propiedade é 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 instantùneos, 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 dinùmica
dos recursos, acabando também por consumir recursos adicionais no sistema.
A possibilidade de modificar dinĂąmicamente as caracteristicas do sistema
também 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-anålise. 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 parùmetros de qualidade de serviço (QdS).
Ă 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 fåcil implantação. Nesta
dissertação é 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 dinùmica da rede. São ainda apresentados vårios
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 expÔe a motivação para a criação do protocolo FTT-SE,
apresenta uma descrição do mesmo, bem como a anålise de algumas das
suas propiedades mais relevantes. SĂŁo ainda apresentados e comparados
modelos de distribuição da QdS. Finalmente, são 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
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 integraciĂłn en dichos servicios de modelos de confianza y reputaciĂłn. En la fase de planificaciĂłn, proponemos una metodologĂa para evaluar la confianza en proveedores de Cloud antes de decidir si el sistema, o parte de Ă©l, se traslada al mismo. En la fase de anĂĄlisis, ofrecemos una notaciĂłn para la captura y representaciĂłn de requisitos de confianza y reputaciĂłn. Asimismo en esta misma fase, desarrollamos una metodologĂa que permite detectar amenazas internas en un sistema a travĂ©s de anĂĄlisis de relaciones de confianza. Para la fase de diseño, proponemos un perfil UML que permite la especificaciĂłn de modelos de confianza y reputaciĂłn, lo cual facilita la siguiente fase de implementaciĂłn, para la que desarrollamos un marco de trabajo que los desarrolladores pueden usar para implementar una amplia variedad de modelos de confianza y reputaciĂłn. Finalmente, para la fase de verificaciĂłn en tiempo de ejecuciĂłn, presentamos un marco de trabajo desarrollado sobre una plataforma de sistemas auto-adaptativos que implementa el paradigma de modelos en tiempo de ejecuciĂłn. Con dicho marco de trabajo, hacemos posible que los desarrolladores puedan implementar modelos de confianza y reputaciĂłn, y que puedan usar la informaciĂłn proporcionada por dichos modelos para especificar polĂticas de reconfiguraciĂłn en tiempo de ejecuciĂłn. Esto permite que el sistema se adapte de forma que se mantengan niveles tolerables de confianza y reputaciĂłn en los componentes de los que consiste. Todo los trabajos anteriores se apoyan sobre un marco conceptual que captura y relaciona entre sĂ las nociones mĂĄs relevantes en los dominios de la confianza y la reputaciĂłn
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