3,492 research outputs found

    Practical applications of data mining in plant monitoring and diagnostics

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    Using available expert knowledge in conjunction with a structured process of data mining, characteristics observed in captured condition monitoring data, representing characteristics of plant operation may be understood, explained and quantified. Knowledge and understanding of satisfactory and unsatisfactory plant condition can be gained and made explicit from the analysis of data observations and subsequently used to form the basis of condition assessment and diagnostic rules/models implemented in decision support systems supporting plant maintenance. This paper proposes a data mining method for the analysis of condition monitoring data, and demonstrates this method in its discovery of useful knowledge from trip coil data captured from a population of in-service distribution circuit breakers and empirical UHF data captured from laboratory experiments simulating partial discharge defects typically found in HV transformers. This discovered knowledge then forms the basis of two separate decision support systems for the condition assessment/defect clasification of these respective plant items

    Foot and Mouth Epidemic Reduces Cases of Human Cryptosporidiosis in Scotland.

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    In Scotland, rates of cryptosporidiosis infection in humans peak during the spring, a peak that is coincident with the peak in rates of infection in farm animals (during lambing and calving time). Here we show that, during the outbreak of foot and mouth disease (FMD) in 2001, there was a significant reduction in human cases of cryptosporidiosis infection in southern Scotland, where FMD was present, whereas, in the rest of Scotland, there was a reduction in cases that was not significant. We associate the reduction in human cases of cryptosporidiosis infection with the reduction in the number of young farm animals, together with restrictions on movement of both farm animals and humans, during the outbreak of FMD in 2001. We further show that, during 2002, there was recovery in the rate of cryptosporidiosis infection in humans throughout Scotland, particularly in the FMD-infected area, but that rates of infection remained lower, though not significantly, than pre-2001 levels

    Limitation of energy deposition in classical N body dynamics

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    Energy transfers in collisions between classical clusters are studied with Classical N Body Dynamics calculations for different entrance channels. It is shown that the energy per particle transferred to thermalised classical clusters does not exceed the energy of the least bound particle in the cluster in its ``ground state''. This limitation is observed during the whole time of the collision, except for the heaviest system.Comment: 13 pages, 15 figures, 1 tabl

    Towards the deployment of customer orientation: A case study in third-party logistics

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    Customer orientation concerns the degree to which an organisation focuses on customers, recognises their desires and places meeting their needs as a first priority. As managing the needs of individual customers in supply chains become increasingly important, logistics companies have been recognising customer orientation as a critical aspect of their success. This study explores some of the challenges in the deployment of customer oriented logistics systems and argues that the so-called product intelligence model can provide an approach for developing such systems. Using an industrial case study, in this paper we examine customer orientation for a third-party logistics provider by examining both the development of information systems that enable the offering of exible logistics offerings to the end customer and the impact of providing these offerings on a company's performance. We conclude with a set of functionalities required by information systems of logistics providers that wish to enhance customer orientation in their offering

    The dispersive self-dual Einstein equations and the Toda lattice

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    The Boyer-Finley equation, or SU(∞)SU(\infty)-Toda equation is both a reduction of the self-dual Einstein equations and the dispersionlesslimit of the 2d2d-Toda lattice equation. This suggests that there should be a dispersive version of the self-dual Einstein equation which both contains the Toda lattice equation and whose dispersionless limit is the familiar self-dual Einstein equation. Such a system is studied in this paper. The results are achieved by using a deformation, based on an associative ⋆\star-product, of the algebra sdiff(Σ2)sdiff(\Sigma^2) used in the study of the undeformed, or dispersionless, equations.Comment: 11 pages, LaTeX. To appear: J. Phys.

    Non equilibrium effects in fragmentation

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    We study, using molecular dynamics techniques, how boundary conditions affect the process of fragmentation of finite, highly excited, Lennard-Jones systems. We analyze the behavior of the caloric curves (CC), the associated thermal response functions (TRF) and cluster mass distributions for constrained and unconstrained hot drops. It is shown that the resulting CC's for the constrained case differ from the one in the unconstrained case, mainly in the presence of a ``vapor branch''. This branch is absent in the free expanding case even at high energies . This effect is traced to the role played by the collective expansion motion. On the other hand, we found that the recently proposed characteristic features of a first order phase transition taking place in a finite isolated system, i.e. abnormally large kinetic energy fluctuations and a negative branch in the TRF, are present for the constrained (dilute) as well the unconstrained case. The microscopic origin of this behavior is also analyzed.Comment: 21 pages, 11 figure

    Automatic analysis of Pole Mounted Auto-Recloser data for fault diagnosis and prognosis

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    Fault diagnosis is a key part of a control and protection engineer’s role to ensure the effective and stable performance of electrical power networks. One challenge is to support the analysis and application of expert judgement to the, often, large data sets generated. To assist engineers with this task and improve network reliability, this research focuses on analysing previous fault activity in order to obtain an early-warning report to assist fault diagnosis and fault prognosis. This paper details the design of an integrated system with a fault diagnosis algorithm utilising available Supervisory Control And Data Acquisition (SCADA) alarm data and 11kV distribution network data captured from Pole Mounted Auto-Reclosers (PMARs) (provided by a leading UK network operator). The developed system will be capable of diagnosing the nature of a circuit’s previous fault activity, underlying circuit activity and evolving fault activity and the risk of future fault activity. This will provide prognostic decision support for network operators and maintenance staff

    Normal-Superconducting Phase Transition Mimicked by Current Noise

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    As a superconductor goes from the normal state into the superconducting state, the voltage vs. current characteristics at low currents change from linear to non-linear. We show theoretically and experimentally that the addition of current noise to non-linear voltage vs. current curves will create ohmic behavior. Ohmic response at low currents for temperatures below the critical temperature TcT_c mimics the phase transition and leads to incorrect values for TcT_c and the critical exponents Îœ\nu and zz. The ohmic response occurs at low currents, when the applied current I0I_0 is smaller than the width of the probability distribution σI\sigma_I, and will occur in both the zero-field transition and the vortex-glass transition. Our results indicate that the transition temperature and critical exponents extracted from the conventional scaling analysis are inaccurate if current noise is not filtered out. This is a possible explanation for the wide range of critical exponents found in the literature.Comment: 4 pages, 2 figure

    Probing the limits of superconductivity

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    DC voltage versus current measurements of superconductors in a magnetic field are widely interpreted to imply that a phase transition occurs into a state of zero resistance. We show that the widely-used scaling function approach has a problem: Good data collapse occurs for a wide range of critical exponents and temperatures. This strongly suggests that agreement with scaling alone does not prove the existence of the phase transition. We discuss a criterion to determine if the scaling analysis is valid, and find that all of the data in the literature that we have analyzed fail to meet this criterion. Our data on YBCO films, and other data that we have analyzed, are more consistent with the occurrence of small but non-zero resistance at low temperature.Comment: 13 page pdf file, figures included To be published in conference proceedings of SPIE 200
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