29 resultados para cybernetics

em Queensland University of Technology - ePrints Archive


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This paper discusses a framework in which catalog service communities are built, linked for interaction, and constantly monitored and adapted over time. A catalog service community (represented as a peer node in a peer-to-peer network) in our system can be viewed as domain specific data integration mediators representing the domain knowledge and the registry information. The query routing among communities is performed to identify a set of data sources that are relevant to answering a given query. The system monitors the interactions between the communities to discover patterns that may lead to restructuring of the network (e.g., irrelevant peers removed, new relationships created, etc.).

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This study explores young people's creative practice through using Information and Communications Technologies (ICTs) - in one particular learning area - Drama. The study focuses on school-based contexts and the impact of ICT-based interventions within two drama education case studies. The first pilot study involved the use of online spaces to complement a co-curricula performance project. The second focus case was a curriculum-based project with online spaces and digital technologies being used to create a cyberdrama. Each case documents the activity systems, participant experiences and meaning making in specific institutional and technological contexts. The nature of creative practice and learning are analysed, using frameworks drawn from Vygotsky's socio-historical theory (including his work on creativity) and from activity theory. Case study analysis revealed the nature of contradictions encountered and these required an analysis of institutional constraints and the dynamics of power. Cyberdrama offers young people opportunities to explore drama through new modes and the use of ICTs can be seen as contributing different tools, spaces and communities for creative activity. To be able to engage in creative practice using ICTs requires a focus on a range of cultural tools and social practices beyond those of the purely technological. Cybernetic creative practice requires flexibility in the negotiation of tool use and subjects and a system that responds to feedback and can adapt. Classroom-based dramatic practice may allow for the negotiation of power and tool use in the development of collaborative works of the imagination. However, creative practice using ICTs in schools is typically restricted by authoritative power structures and access issues. The research identified participant engagement and meaning making emerging from different factors, with some students showing preferences for embodied creative practice in Drama that did not involve ICTs. The findings of the study suggest ICT-based interventions need to focus on different applications for the technology but also on embodied experience, the negotiation of power, identity and human interactions.

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This work is a digital version of a dissertation that was first submitted in partial fulfillment of the Degree of Doctor of Philosophy at the Queensland University of Technology (QUT) in March 1994. The work was concerned with problems of self-organisation and organisation ranging from local to global levels of hierarchy. It considers organisations as living entities from local to global things that a living entity – more particularly, an individual, a body corporate or a body politic - must know and do to maintain an existence – that is to remain viable – or to be sustainable. The term ‘land management’ as used in 1994 was later subsumed into a more general concept of ‘natural resource management’ and then merged with ideas about sustainable socioeconomic and sustainable ecological development. The cybernetic approach contains many cognitive elements of human observation, language and learning that combine into production processes. The approach tends to highlight instances where systems (or organisations) can fail because they have very little chance of succeeding. Thus there are logical necessities as well as technical possibilities in designing, constructing, operating and maintaining production systems that function reliably over extended periods. Chapter numbers and titles to the original thesis are as follows: 1. Land management as a problem of coping with complexity 2. Background theory in systems theory and cybernetic principles 3. Operationalisation of cybernetic principles in Beer’s Viable System Model 4. Issues in the design of viable cadastral surveying and mapping organisation 5. An analysis of the tendency for fragmentation in surveying and mapping organisation 6. Perambulating the boundaries of Sydney – a problem of social control under poor standards of literacy 7. Cybernetic principles in the process of legislation 8. Closer settlement policy and viability in agricultural production 9. Rate of return in leasing Crown lands

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Information security policy defines the governance and implementation strategy for information security in alignment with the corporate risk policy objectives and strategies. Research has established that alignment between corporate concerns may be enhanced when strategies are developed concurrently using the same development process as an integrative relationship is established. Utilizing the corporate risk management framework for security policy management establishes such an integrative relationship between information security and corporate risk management objectives and strategies. There is however limitation in the current literature on presenting a definitive approach that fully integrates security policy management with the corporate risk management framework. This paper presents an approach that adopts a conventional corporate risk management framework for security policy development and management to achieve alignment with the corporate risk policy. A case example is examined to illustrate the alignment achieved in each process step with a security policy structure being consequently derived in the process. It is shown that information security policy management outcomes become both integral drivers and major elements of the corporate-level risk management considerations. Further study should involve assessing the impact of the use of the proposed framework in enhancing alignment as perceived in this paper.

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In an open railway access market price negotiation, it is feasible to achieve higher cost recovery by applying the principles of price discrimination. The price negotiation can be modeled as an optimization problem of revenue intake. In this paper, we present the pricing negotiation based on reinforcement learning model. A negotiated-price setting technique based on agent learning is introduced, and the feasible applications of the proposed method for open railway access market simulation are discussed.

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A schedule coordination problem involving two train services provided by different operators is modeled as an optimization of revenue intake. The coordination is achieved through the adjustment of commencement times of the train services by negotiation. The problem is subject to constraints regarding to passenger demands and idle costs of rolling-stocks from both operators. This paper models the operators as software agents having the flexibility to incorporate one of the two (and potentially more) proposed negotiation strategies. Empirical results show that agents employing different combination of strategies have significant impact on the quality of solution and negotiation time.

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With the recent regulatory reforms in a number of countries, railways resources are no longer managed by a single party but are distributed among different stakeholders. To facilitate the operation of train services, a train service provider (SP) has to negotiate with the infrastructure provider (IP) for a train schedule and the associated track access charge. This paper models the SP and IP as software agents and the negotiation as a prioritized fuzzy constraint satisfaction (PFCS) problem. Computer simulations have been conducted to demonstrate the effects on the train schedule when the SP has different optimization criteria. The results show that by assigning different priorities on the fuzzy constraints, agents can represent SPs with different operational objectives.

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This correspondence paper addresses the problem of output feedback stabilization of control systems in networked environments with quality-of-service (QoS) constraints. The problem is investigated in discrete-time state space using Lyapunov’s stability theory and the linear inequality matrix technique. A new discrete-time modeling approach is developed to describe a networked control system (NCS) with parameter uncertainties and nonideal network QoS. It integrates a network-induced delay, packet dropout, and other network behaviors into a unified framework. With this modeling, an improved stability condition, which is dependent on the lower and upper bounds of the equivalent network-induced delay, is established for the NCS with norm-bounded parameter uncertainties. It is further extended for the output feedback stabilization of the NCS with nonideal QoS. Numerical examples are given to demonstrate the main results of the theoretical development.

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This paper presents Multi-Step A* (MSA*), a search algorithm based on A* for multi-objective 4D vehicle motion planning (three spatial and one time dimension). The research is principally motivated by the need for offline and online motion planning for autonomous Unmanned Aerial Vehicles (UAVs). For UAVs operating in large, dynamic and uncertain 4D environments, the motion plan consists of a sequence of connected linear tracks (or trajectory segments). The track angle and velocity are important parameters that are often restricted by assumptions and grid geometry in conventional motion planners. Many existing planners also fail to incorporate multiple decision criteria and constraints such as wind, fuel, dynamic obstacles and the rules of the air. It is shown that MSA* finds a cost optimal solution using variable length, angle and velocity trajectory segments. These segments are approximated with a grid based cell sequence that provides an inherent tolerance to uncertainty. Computational efficiency is achieved by using variable successor operators to create a multi-resolution, memory efficient lattice sampling structure. Simulation studies on the UAV flight planning problem show that MSA* meets the time constraints of online replanning and finds paths of equivalent cost but in a quarter of the time (on average) of vector neighbourhood based A*.