212,208 research outputs found

    Knowledge transformers : a link between learning and creativity

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    The purpose of this paper is to investigate whether knowledge transformers which are featured in the learning process, are also present in the creative process. This is achieved by reviewing models and theories of creativity and identifying the existence of the knowledge transformers. The investigation shows that there is some evidence to show that the creative process can be explained through knowledge transformers. Hence, it is suggested that one of links between learning and creativity is through the knowledge transformers

    Prediction of remaining life of power transformers based on left truncated and right censored lifetime data

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    Prediction of the remaining life of high-voltage power transformers is an important issue for energy companies because of the need for planning maintenance and capital expenditures. Lifetime data for such transformers are complicated because transformer lifetimes can extend over many decades and transformer designs and manufacturing practices have evolved. We were asked to develop statistically-based predictions for the lifetimes of an energy company's fleet of high-voltage transmission and distribution transformers. The company's data records begin in 1980, providing information on installation and failure dates of transformers. Although the dataset contains many units that were installed before 1980, there is no information about units that were installed and failed before 1980. Thus, the data are left truncated and right censored. We use a parametric lifetime model to describe the lifetime distribution of individual transformers. We develop a statistical procedure, based on age-adjusted life distributions, for computing a prediction interval for remaining life for individual transformers now in service. We then extend these ideas to provide predictions and prediction intervals for the cumulative number of failures, over a range of time, for the overall fleet of transformers.Comment: Published in at http://dx.doi.org/10.1214/00-AOAS231 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Superconducting Transformers

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    An Analysis of Illocutioanry Acts of the Main Character of Transformers Movie “Dark of the Moon”

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    The objectives of this research were to find out the five types of illocutionary acts, namely: Directive, Commisives, Expressive, Assertive, Declarative and the dominant one used in Transformers”Dark of the Moon”. This research was conducted by using quantitative descriptive design. It took 735 utterances taken from the subtitle of Transformers “Dark of the Moon” which were released in June 29, 2011. The result of analyzing found five types of process were used in Transformers “Dark of the Moon”, they were: Directive, Commisive, Expressive, Assertive and Declarative. There were 735 illocutionary acts in 735 utterances. The findings of data analysis showed that the total numbers of process from the five types of illocutionary acts were: Directive is 361 (47,94%) utterances. The total number of Commisive is 39 (5,17%) utterances. The total number of Expressive is 58 (7,70%) utterances. The total number of Assertives is 294 (39,04%). And the total number of Declaratives is 1 (0,13%). It means that Directive is the most dominant type of Illocutionary Acts used in Transformers “Dark of the Moon” movie

    Apparatus including a plurality of spaced transformers for locating short circuits in cables

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    A cable fault locator is described for sensing faults such as short circuits in power cables. The apparatus includes a plurality of current transformers strategically located along a cable. Trigger circuits are connected to each of the current transformers for placing a resistor in series with a resistive element responsive to an abnormally high current flowing through that portion of the cable. By measuring the voltage drop across the resistive element, the location of the fault can be determined

    Simple planar Bragg grating devices for photonic Hilbert transform

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    Hilbert transformers are important devices widely used in information processing and signal analysis in the electronic domain. For example, for spectral efficiency improvement, it is used to construct the analytic signal for single sideband (SSB) modulation from a real signal. Photonic Hilbert transformers (PHTs) are proposed for a similar range of applications and would allow the direct processing of optical signals at bandwidths far beyond current electronic technologies

    Turn-to-turn fault protection technique for synchronous machines without additional voltage transformers

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    This paper presents a novel protection technique for the detection of inter-turn faults in synchronous machines. It is based on the calculation of voltage in the stator windings from the usual phases and neutral voltage, typically available in allgenerator protection relays. The existing turn-to-turn protection mechanisms require additional voltage transformers. The main contribution of this technique is that it can be implemented without using any additional voltage transformers. Thistechnique has been successfully tested in a special synchronous machine with taps in the stator windings, where turn-to-turn faults have been created
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