In this paper, expressions of the neutral conductor current in three-phase networks with compact fluorescent lamps (CFLs) are obtained from a CFL "black-box" model proposed in the literature. These expressio...
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In this paper, expressions of the neutral conductor current in three-phase networks with compact fluorescent lamps (CFLs) are obtained from a CFL "black-box" model proposed in the literature. These expressions allow studying and performing a sensitivity analysis of the impact of CFLs on neutral current. The influence of CFL model parameters, as well as supply voltage unbalance, number of CFLs per phase and different types of CFLs per phase, on the neutral current is also investigated. The obtained results are validated with measurements and PSCAD/EMTDC simulations. (C) 2013 Elsevier B.V. All rights reserved.
Compact fluorescent lamps (CFLs) are increasingly present in low voltage distribution systems due to their small energy consumption in comparison with traditional incandescent lamps. This damages power quality because...
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Compact fluorescent lamps (CFLs) are increasingly present in low voltage distribution systems due to their small energy consumption in comparison with traditional incandescent lamps. This damages power quality because CFLs have a non-linear behavior and inject harmonics into the distribution system. This paper studies estimation procedures for CFLs and presents estimation algorithms based on a "black box" CFL model and actual measurements. The estimation procedures are validated with laboratory measurements. (c) 2012 Elsevier B.V. All rights reserved.
An approach for the design of 1-D and 2-D FIR digital filters with complex coefficients is presented. In this approach, the error measure is formulated as a quadratic function and the filter coefficients are obtained ...
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An approach for the design of 1-D and 2-D FIR digital filters with complex coefficients is presented. In this approach, the error measure is formulated as a quadratic function and the filter coefficients are obtained by solving a set of linear equations. The proposed approach is more efficient than the eigenfilter approach regarding the amount of computation and design time. Moreover, the proposed approach leads to smaller least-squares errors. Design examples are included to illustrate the advantages of the approach. (C) 1997 Elsevier Science Ltd.
In many communication systems, training sequences are used to help the receiver identify and/or equalize the channel, The amount of training data required depends on the convergence properties of the adaptive filterin...
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In many communication systems, training sequences are used to help the receiver identify and/or equalize the channel, The amount of training data required depends on the convergence properties of the adaptive filtering algorithms used for equalization. In this paper, we propose the use of a new adaptive filtering method called interior point leastsquares (IPLS) for adaptive equalization. First, we show that IPLS converges exponentially fast in the transient phase. Then, we use the IPLS algorithm to update the weight vector for a minimum-mean-square-error decision-feedback equalizer (MMSE-DFE) in a CDMA downlink scenario. Numerical simulations show that when training sequences are short, IPLS consistently outperforms RLS in terms of system bit-error-rate and packet error rate. As the training sequence gets longer IPLS matches the performance of the RLS algorithm.
Low-power single-phase loads using single-phase uncontrolled rectifiers with dc-smoothing capacitors as their power supply are increasingly present in low-voltage distribution systems, causing high-voltage distortions...
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Low-power single-phase loads using single-phase uncontrolled rectifiers with dc-smoothing capacitors as their power supply are increasingly present in low-voltage distribution systems, causing high-voltage distortions. This paper studies the estimation procedure of single-phase rectifier parameters and presents an estimation algorithm based on a rectifier model and actual measurements. The model and the estimation procedure are described and validated with measurements in the laboratory and household installations, respectively.
A major challenge while communicating in dynamic channels, such as the. underwater acoustic channel, is the large amount of time-varying inter-symbol interference (ISI) due to multipath. In many realistic channels, th...
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A major challenge while communicating in dynamic channels, such as the. underwater acoustic channel, is the large amount of time-varying inter-symbol interference (ISI) due to multipath. In many realistic channels, the fluctuations between different taps of the sampled channel impulse response are correlated. Traditional least-squares algorithms used for adapting channel equalizers do not exploit this correlation structure. A channel subspace post-filtering Algorithm is presented that treats the least-squares channel estimate as a noisy time series and exploits the;channel correlation structure to reduce the channel estimation error. The improvement in performance of the post-filtered channel estimator is predicted theoretically and demonstrated using both simulation and experimental data. Experimental data is also used to demonstrate the improvement in performance of a channel estimate-based decision feedback equalizer that uses this post-filtered channel estimate to determine the equalizer coefficients.
Motivation: Metabolomics datasets are generally large and complex. Using principal component analysis (PCA), a simplified view of the variation in the data is obtained. The PCA model can be interpreted and the process...
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Motivation: Metabolomics datasets are generally large and complex. Using principal component analysis (PCA), a simplified view of the variation in the data is obtained. The PCA model can be interpreted and the processes underlying the variation in the data can be analysed. In metabolomics, often a priori information is present about the data. Various forms of this information can be used in an unsupervised data analysis with weighted PCA (WPCA). A WPCA model will give a view on the data that is different from the view obtained using PCA, and it will add to the interpretation of the information in a metabolomics dataset. Results: A method is presented to translate spectra of repeated measurements into weights describing the experimental error. These weights are used in the data analysis with WPCA. The WPCA model will give a view on the data where the non-uniform experimental error is accounted for. Therefore, the WPCA model will focus more on the natural variation in the data.
Time-division multiple access (TDMA) is a digital multiplexing technique that is widely used in some cellular communication systems. Although the user time slots within a cell are designed to be synchronized with each...
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Time-division multiple access (TDMA) is a digital multiplexing technique that is widely used in some cellular communication systems. Although the user time slots within a cell are designed to be synchronized with each other, they are asynchronous with time slots in nearby cells operating on the same carrier frequencies. The resulting cochannel interference is an important consideration in such systems because it influences the cell size and the quality of service. This paper provides an overview of an adaptive array that is capable of separating and demodulating cochannel signals in a sequential manner. least-squares algorithms with training are employed to compute the array (beamformer) coefficients such that several cochannel signals are rejected. The array output contains an estimate of one cochannel signal that is equalized and processed by the detector.
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