1,720,955 research outputs found
Position of an electro hydraulic servo system using fuzzy logic
No full textBu çalışmada, bir elektro hidrolik servo sistemin bulanık mantık yaklaşımıyla konum kontrolü gerçekleştirilmiştir. Sistemin ana elemanları olan servovalf, hidrolik silindir ve hidrolik güç ünitesinin matematik modelleri oluşturulmuş, hidrolik akışkanın sıkıştırılabilirliği, sistemin sürtünmesi ve ataleti modele dâhil edilmiştir. Elde edilen ® modeller MATLAB /SIMULINK ortamına aktarılarak elektro hidrolik servo sistemin dinamik modeli elde edilmiştir. Sistemin simülasyonu ve bulanık mantık kontrolü ® MATLAB /SIMULINK ortamında gerçekleştirilmiştir. Elektro hidrolik sisteme uygulanacak olan bulanık mantık yaklaşımı ile konum kontrolünde, konum hatası ve konum hatasının değişimi kullanılarak bulanık mantık kontrolünün yapısı oluşturulmuştur. Adım, rampa ve sinüzoidal referans girişleri için simülasyon neticeleri ışığında konum izlemede elde edilen sonuçlar incelenmiştir. Sisteme bulanık mantık kontrolün yanı sıra PD kontrol de uygulanmış ve her ikisi karşılaştırılmıştır. Elde edilen bütün sonuçlar grafik şeklinde verilmiştir. Elde edilen sayısal sonuçlar fiziksel anlamları açısından tartışılmıştır.In this study, fuzzy logic control of a electro hydraulic servo system is realized for position control. Mathematical model of servo valve, hydraulic cylinder and hydraulic power unit which are main parts of system is obtained and the pressing capability of hydraulic fluid, friction and inertia of system are included in the system mathematical ® model. These obtained models are transferred into MATLAB /SIMULINK domain. Mathematical model of system, PD (Proportional and Derivative) and fuzzy logic ® controllers (FLC) are created in MATLAB /SIMULINK. Fuzzy logic control structure is examined by using feedback of position error and derivative of position error to apply FLC to electro hydraulic servo system. Because of complexity of dynamic system behaviors and change of electro hydraulic servo system characteristics with time FLC is preferred. Consequently, simulation results of position control for step, ramp and sine reference inputs are evaluated. Susceptible position control of hydraulic system is obtained with using FLC. PD control is also applied to system for comparing with results of FLC. Results are presented in graphical form. Physical trends of the obtained numerical results are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Mathematical modelling and fuzzy logic based position control of an electrohydraulic servosystem with internal leakage
No full textThis paper describes an application of a fuzzy logic position control to an electrohydraulic servosystem. Mathematical model of the electrohydraulic servosystem is obtained considering the internal leakage within the servosystem. Electrohydraulic servosystems are one of the most commonly used actuators. However, electrohydraulic servosystems are difficult to control due to nonlinearity and complexity of their mathematical models. In this paper, as a first step, the mathematical models of the main components of the servosystem are obtained. The effect of compressibility, friction, internal leakage in servovalve, leakage in actuator and inertia are included in the model. Since the system has a complex structure and the system characteristics are time dependent. Fuzzy Logic Control (FLC) is applied to the electrohydraulic servosystem. The error and change in error are employed in the FLC. The effect of internal leakage on the mathematical model and performance of the position control system is investigated. Numerical simulation results for position control under a square wave reference input are obtained. Results are presented in graphical form. Physical trends of numerical simulation results are discussed. Although leakage is often ignored in dynamic analysis of servosystems, results shown in the paper indicate that the leakage has a significant effect on the mathematical model and performance of the position control system at small spool displacements. (C) 2009 Elsevier Ltd. All rights reserved
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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