186,242 research outputs found
Enhanced segmentation of disturbance records by adaptive thresholding
No full textTo analyse power system fault events captured by disturbance recorders the sampled analogue waveforms (voltages and currents) have to be segmented into system states (pre-fault, fault,...). In this paper a combination of wavelet transform (WT) and linear prediction coding (LPC) is applied to the symmetrical space phasor signals of the voltage and current waveforms. The signals obtained contain impulses when the system state changes abruptly. A threshold for segmentation is calculated using median filtering with adaptive window length. The segment borders are finally merged and validated.Stachel Philipp, Schegner Peter and Zivanovic, Rastko;http://www.pscc2008.org
Parameter identification of unsymmetrical transmission lines using fault records obtained from protective relays
No full textDuring a fault, protection relays of the faulty line as well as adjacent lines react and record measurement data. The records of an adjacent healthy line can be used for line parameter identification. The special feature of the proposed method is the consideration of unsymmetrical transmission lines and the application of a high-accuracy signal modeling technique. Derived from a π line model, an estimation equation for determining the different impedances is developed. This equation contains the signal models of measurements as well as their time derivatives, which can be estimated very precisely compared to the classical approach based on filtering. By means of a simple simulation model, the accuracy of the proposed algorithm is compared to an approach previously proposed which is based on deconvolution and filtering methods as well as on the representation of a transmission line using time-varying phasors.Roberto Schulze, Peter Schegner Rastko Živanovi
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Identification of the resonant-grounded system parameters by evaluating fault measurement records
No full textCopyright © 2004 IEEEThe operation of a resonant-grounded network during an earth-fault condition depends on the three basic parameters: damping, detuning, and unbalance factor. These parameters are influenced by the environmental conditions (e.g. humidity, temperature, and pollution), and the network topology. Accurate values of these parameters during an earth-fault condition are required to examine the operation of the compensation system. The fault records could be used for that purpose. The recorded neutral-to-ground voltage signals have been parameterized (using damping and detuning as parameters) according to the mathematical model of the transient process. Iteratively reweighted least squares algorithm has been used to fit the model. This algorithm is the major improvement over the classical least squares approach. It is able to filter out noise more efficiently. As a direct result, very accurate parameter identification has been achieved. This paper concludes with the practical examples.Rastko Zivanovic´, Peter Schegner, Olaf Seifert, and Georg Pil
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Dr. Edward P. Wimberly, ITC, July 2011
No full textThis video is a conversation with Dr. Edward P. Wimberly. Dr. Wimberly talks about his book, "No Shame in Wesley's Gospel: A Twenty-First Century Pastoral Gospel". Brad Ost, AUC Woodruff Library, is the interviewer
Author Rights and Scholarly Publishing
No full textOriginally posted at
http://blog.library.gsu.edu/2014/10/24/author-rights-and-scholarly-publishing/</p
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