3,394,013 research outputs found

    Support Vector Regression Based S-transform for Prediction of Single and Multiple Power Quality Disturbances

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    This paper presents a novel approach using Support Vector Regression (SVR) based S-transform to predict the classes of single and multiple power quality disturbances in a three-phase industrial power system. Most of the power quality disturbances recorded in an industrial power system are non-stationary and comprise of multiple power quality disturbances that coexist together for only a short duration in time due to the contribution of the network impedances and types of customers’ connected loads. The ability to detect and predict all the types of power quality disturbances encrypted in a voltage signal is vital in the analyses on the causes of the power quality disturbances and in the identification of incipient fault in the networks. In this paper, the performances of two types of SVR based S-transform, the non-linear radial basis function (RBF) SVR based S-transform and the multilayer perceptron (MLP) SVR based S-transform, were compared for their abilities in making prediction for the classes of single and multiple power quality disturbances. The results for the analyses of 651 numbers of single and multiple voltage disturbances gave prediction accuracies of 86.1% (MLP SVR) and 93.9% (RBF SVR) respectively. Keywords: Power Quality, Power Quality Prediction, S-transform, SVM, SV

    Power types in explicit mathematics?

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    In this note it is shown that in explicit mathematics the strong power type axiom is inconsistent with (uniform) elementary comprehension and discuss some general aspects of power types in explicit mathematic

    What is Power Sharing? Consociationalism, Centripetalism, and Hybrid Power Sharing

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    In this article, the author analyzes the term "power-sharing" in the context of power exercised within a state. He first examines the term in the very general sense, in which it can be applied to all types and dimensions of sharing of power between various groups and institutional entities. Second, the author examines the meaning of the term in the narrow sense, that is, the phenomenon of systemic sharing of power by groups (segments) whose membership is based on ascribed criteria such as common ancestors, relatives, or racial background, and/or cultural ones such as a common language, religion, or celebrations. The basic segmental units in this sense are nations (understood in the sociological sense), ethnic groups, or religious and denominational communities that form part of divided societies. Third, the article shows the differences between the principal models (types) of power-sharing in the narrow sense: consociationalism, centripetalism, and hybrid power-sharing

    MIMO Transceiver Optimization With Linear Constraints on Transmitted Signal Covariance Components

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    This correspondence revisits the joint transceiver optimization problem for multiple-input multiple-output (MIMO) channels. The linear transceiver as well as the transceiver with linear precoding and decision feedback equalization are considered. For both types of transceivers, in addition to the usual total power constraint, an individual power constraint on each antenna element is also imposed. A number of objective functions including the average bit error rate, are considered for both of the above systems under the generalized power constraint. It is shown that for both types of systems the optimization problem can be solved by first solving a class of MMSE problems (AM-MMSE or GM-MMSE depending on the type of transceiver), and then using majorization theory. The first step, under the generalized power constraint, can be formulated as a semidefinite program (SDP) for both types of transceivers, and can be solved efficiently by convex optimization tools. The second step is addressed by using results from majorization theory. The framework developed here is general enough to add any finite number of linear constraints to the covariance matrix of the input

    Durable goods monopoly with stochastic costs

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    I study the problem of a durable goods monopolist who lacks commitment power and whose marginal cost of production varies stochastically over time. I show that a monopolist with stochastic costs usually serves the different types of consumers at different times and charges them different prices. When the distribution of consumer valuations is discrete, the monopolist exercises market power and there is inefficient delay. When there is a continuum of types, the monopolist cannot extract rents and the market outcome is efficient

    Odd multiperfect numbers of abundancy 4

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    Euler's structure theorem for any odd perfect number is extended to odd multiperfect numbers of abundancy power of 2. In addition, conditions are found for classes of odd numbers not to be 4-perfect: some types of cube, some numbers divisible by 9 as the maximum power of 3, and numbers where 2 is the maximum even prime power
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