1,720,955 research outputs found
Kontrol Arus dengan Hysteresis-Band Adaptif Menggunakan Lookup-Table pada H-Bridge Bidirectional Dc-Dc Converter untuk Pengisian Baterai Mobil Listrik
No full textKebijakan dekarbonisasi energi di seluruh dunia mempromosikan penggunaan energi terbarukan yang meningkat untuk pembangkitan dan elektrifikasi transportasi secara besar-besaran. Sejalan dengan kebijakan ini, penggunaan penyimpanan energi pada electric vehicle (EV) yang cukup besar, dapat membantu integrasi energi terbarukan sebagai sumber daya dengan sebutan vehicle to grid (V2G). Permasalahan utama pada penyimpanan ini terletak pada pelepasan energi dari baterai yang tidak sanggup mentransfer kembali energi ke grid. Elemen kunci dari sistem V2G adalah konverter yang memiliki fitur bidirectional sehingga dapat charging dan discharging baterai EV. Penelitian terkait konverter bidirectional ini telah banyak dikembangkan, salah satunya adalah topologi konverter h-bridge yang memiliki rentang tegangan keluaran yang lebar dan ripple arus yang kecil. Selain jenis topologi konverter, metode kontrol arus yang dapat merespon perubahan dinamis dengan cepat, akurat, dan simpel dalam pengaplikasiannya juga sangat penting. Penelitian ini mengusulkan kontrol arus dengan hysteresis-band adaptif menggunakan metode lookup-table yang diterapkan pada kontrol arus konverter dc-dc. Hasil yang diharapkan adalah respon cepat dan akurat dari sistem kontrol pada perubahan nilai referensi arus, tegangan masukan, dan tegangan keluaran. Selain itu variabel hysteresis bandwidth (HB) yang adaptif diharapkan mampu membatasi kinerja MOSFET pada frekuensi tinggi dan tidak beraturan yang membuat rugi-rugi switching dan frequency noise. Untuk memvalidasi performa kontrol yang diusulkan dilakukan simulasi menggunakan software PSIM dan pengujian skala laboratorium dengan membuat prototip konverter dc-dc. Hasil penelitian menunjukkan frekuensi terjaga konstan pada rata-rata 14,88kHz dengan rentang ∆f= 0,79kHz dan η 85,74% saat mode charging. Saat discharging frekuensi konstan pada rata-rata 16,62kHz dengan rentang ∆f= 0,33kHz dan η 77,40%. Penelitian ini dapat dijadikan referensi dalam pembuatan sistem kontrol simpel dan mudah diimplementasikan pada sistem penyimpanan energi kendaraan listrik.
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Decarbonization policies worldwide encourage the use of renewable energy to generate electricity and electrify transport. In line with these policies, the use of energy storage systems in electric vehicles (EV) can support the integration of renewable energy as a resource called vehicle to grid (V2G). This system of equipment has a problem because the energy it produces can’t be inject directly back into the grid. An essential element of the V2G system is the bidirectional converter which can charge and discharge EV Batteries. Research related to bidirectional converters has been developed a lot. One of these converter topologies that have a wide output voltage range and smaller current ripple is the H-bridge converter. In addition to the type of converter, a current control method that can respond to dynamic changes quickly, accurately, and is simple to implement is also very important. Using lookup-table method, this research aims to control the DC-DC current converter with adaptive hysteresis bandwidth. The proposed control system is expected to have a fast and accurate response to changes in the reference value of the current, input voltage, and output voltage. In addition, the adaptive variable hysteresis bandwidth (HB) is expected to limit the performance of MOSFET at high and irregular frequencies that make switching losses and frequency noise. Simulations were conducted using PSIM and laboratory-scale testing by making a prototype DC-DC converter to validate the proposed control performance. The results indicate that the frequency is maintained at an average of 14,88 kHz with a range of ∆f = 0,79 kHz and η 85,74% during the charging mode. Conversely, during the discharging mode, the frequency is observed to be constant at an average of 16,62 kHz with a range of ∆f = 0,33 kHz and η 77,40%. This research can be used as a reference in making control systems that are simple and easy to implement in electric vehicle energy storage systems
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
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
Automatic Excitation Control Using PI Method Based on Analysis Root Locus for Synchronous Generator
Full text linkThe demand for electrical energy is increasing (at 2–3 percent per year). It is necessary to utilize the energy available in nature optimally and stably to fulfill electricity needs. Synchronous generators have an essential role in fulfilling electricity needs. Maintaining and improving the operational stability of the synchronous generator is fundamental to the safe and economical operation of an electric power system. The use of control methods to increase control excitation is recognized as an economical and effective way. Previous research shows there are still areas for improvement in the excitation control method. Thus, this research focuses on optimizing the automatic excitation system using the PI control method with stability analysis using the root locus. The effect of PI control on the results of the characteristics response has Tr is 1.9 s, Ts is 6.6 s, Mp is 38.95 percent, and Ess is 11.02 percent. While the generator excitation current will increase in line with the increase in load current, and the resulting output voltage will be stable with errors that occur when compared to the nominal voltage is 10.51 percent because the sensor reading is affected by a frequency that is not following the operating frequency.DOI: 10.17977/um024v8i12023p03
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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