1,720,987 research outputs found
A comprehensive control strategy of railway power quality compensator for AC traction power supply systems
No full textThe development of electrical railway systems leads to critical power quality problems in the power grid. This paper discusses a kind of half-bridge-based railway power quality compensator system (HBRPQC) that can compensate negative sequence currents, harmonics, and reactive power simultaneously. In order to keep the HBRPQC performance efficient for the different kinds of transformers used in traction power supply substations, a new multifunctional control strategy that performs better than previous methods is proposed. Due to the fast dynamicity of traction loads, a recessive self-Tuning PI controller based on fuzzy logic is adopted in the current control system. The output control variables are integrated with carrier-based pulse width modulation techniques to generate the pulse signals of HBRPQC switches. The performance of the proposed control strategy is verified for V/V, Yd11, and Scott transformers by simulation and the results prove the effectiveness of the strategy
Typing methods used in the molecular epidemiology of microbial pathogens: a how-to guide
Full text linkMicrobial typing is often employed to determine the source and routes of infections, confirm or rule out outbreaks, trace cross-transmission of healthcare-associated pathogens, recognize virulent strains and evaluate the effectiveness of control measures. Conventional microbial typing methods have occasionally been useful in describing the epidemiology of infectious diseases. However, these methods are generally considered too variable, labour intensive and time-consuming to be of practical value in epidemiological investigations. Moreover, these approaches have proved to be insufficiently discriminatory and poorly reproducible. DNA-based typing methods rely on the analysis of the genetic material of a microorganism. In recent years, several methods have been introduced and developed for investigation of the molecular epidemiology of microbial pathogens. Each of them has advantages and limitations that make them useful in some studies and restrictive in others. The choice of a molecular typing method therefore will depend on the skill level and resources of the laboratory and the aim and scale of the investigation. This study reviews the most popular DNA-based molecular typing methods used in the epidemiology of bacterial pathogens together with their advantages and limitations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Multifunctional control strategy of half-bridge based railway power quality conditioner for traction system
No full textThe extension of electrical railway systems causes critical power quality problems in the power grid. This paper presents a kind of Half-Bridge Railway static Power Quality Conditioner (HBRPQC) based on a half-bridge converter which can compensate Negative Sequence Currents (NSC), harmonics and reactive power simultaneously. In this paper, a new multifunctional control strategy based on modified instantaneous reactive power (p-q) theory is proposed to keep the HBRPQC performance efficient and suitable for different kinds of transformers used in Traction Power supply Substation (TPS). Due to the fast dynamic of traction loads, a hysteresis current controller is used to generate pulse signals of HBRPQC switches. Finally, the presented control method is simulated for V/V and Y/Δ11 transformers by Matlab/Simulink software. The simulation results validate the correctness of proposed control method. © 2013 IEEE
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
