1,720,989 research outputs found
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
The Effect of Flat Plate Theory Assumption in Post-Stall Lift and Drag Coefficients Extrapolation with Viterna Method
No full textIn employing blade element momentum (BEM) method to compute the performance of a turbine propeller, the lift and drag coefficients of propeller element/airfoil are needed. The coefficients are usually obtained from model experiment. Unfortunately, the model experiment can only be conducted for small angle of attack until stall mode. Beyond stall mode, Viterna extrapolation method is commonly used. The method is used to predict the lift and drag coefficients from stall angle to 90o. Beyond that range, besides Viterna method, original flat plate theory assumption can also be adopted. The present study compares the lift and drag coefficients extrapolation using Viterna method and flat plat theory. NACA2415 airfoil shape is used for computation. The computation formulas and procedures are presented and important parameter effect to the coefficients are shown and explained
Design Optimization and Performance Evaluation of a Floating Breakwater
Get PDFIn order to design an optimal floating breakwater with a high performance in a wide range of frequencies, its characteristics and performance in 2D and 3D cases are analyzed. For obtaining an optimal 2D model shape, an optimization method called Genetic Algorithm (GA) combined with Boundary Element Method (BEM) is employed. The accuracy of BEM analysis is confirmed using numerical relations such as Haskind-Newman and energy conservation relations. Moreover, since the investigated model will be an asymmetric shape, an experiment is also conducted to confirm that the present analysis could treat asymmetric body case correctly. However, because the performance of the obtained 2D model is expected to be different for some extent from real application, the performance of the corresponding model in 3D case is also analyzed using Higher Order Boundary Element Method (HOBEM). 3D Wave effect and its effect to the floating breakwater performance are analyzed and discussed. It is shown from this study that the combination of GA and BEM is effective in obtaining an optimal performance model. Moreover, it is also shown that the 3D wave effect is small on motion amplitudes while the wave elevations are found to be in 3D pattern even for a longer body length
Comparison of the Performance-Degrading Near-Interface Traps in Commercial SiC MOSFETs
No full textThis paper presents a comparison of the density of performance-degrading near-interface traps (NITs) in the most commonly available 1200 V commercial N-channel SiC power metal–oxide–semiconductor field-effect transistors (MOSFETs). A recently developed integrated-charge technique was used to measure the density of NITs with energy levels aligned to the conduction band, which degrade MOSFET’s performance by capturing and releasing electrons from the channel biased in the strong-inversion condition. Trench MOSFETs of one manufacturer have lower densities of these NITs in comparison to MOSFETs with the planar gate structure, corresponding to observed higher channel-carrier mobility in trench MOSFETs. Different response-time distributions were also observed, corresponding to different spatial location of the measured NITs.Full Tex
Mapping the ocean energy density around sulawesi and maluku islands
No full textIn order to harvest ocean wind energy around Sulawesi and Maluku Islands, several studies have been conducted to assess the use of a mobile floating structure (MFS) in the sea areas. From the studies, the monthly locations of the MFS were determined by computing one particular location on each sea areas. The MFS locations were determined to be the locations with highest energy density every month. However, in order to obtain more optimal results, an interpolation method need to be implemented to determine the energy density covering all sea areas. In the present study, Kriging method is adopted to interpolate wind energy density on all areas based on the results obtained previously. Energy density maps are then drawn using software packages called ArcGIS and ArcMAP. Based on these maps, the locations of the MFS every month can be determined more accurately
Studi Karakteristik Turbin pada Sistem Konversi Energi Angin
No full textDalam menghitung dan menganalisa densitas energi angin di sebuah lokasi, distribusi Weibull dengan 2 parameter menjadi salah satu jenis distribusi yang paling sering digunakan. Kedua parameter distribusi Weibull yang dimaksud adalah parameter bentuk dan parameter skala. Kedua parameter ini dapat ditentukan dengan menggunakan beberapa metode antara lain metode regresi linear, metode keserupaan maksimum, metode momen, dan lain-lain. Namun demikian, besarnya energi listrik yang akan dihasilkan oleh sebuah sistem konversi energi angin (SKEA) tidak hanya ditentukan oleh nilai kedua parameter tersebut, tetapi juga oleh karakteristik turbin yang digunakan dalam proses konversi. Dalam penelitian ini, karakteristik turbin yang yang dapat digunakan untuk mengkonversi energi angin menjadi energi listrik secara maksimal akan dikaji. Metode perhitungan yang digunakan berdasarkan prinsip teori elemen daun (blade element theory). Teori ini membagi daun propeller ke dalam sejumlah elemen kemudian menjumlahkan efek aliran pada setiap elemen untuk mendapatkan total pengaruh aliran. Data angin yang digunakan pada penelitian sebelumnya akan digunakan sebagai contoh perhitungan. Beberapa karakteristik turbin yang berbeda akan disimulasi dan dianalisa untuk mengetahui pengaruhnya terhadap daya yang dihasilkan. Metode perhitungan yang digunakan dalam penelitian ini diimplementasikan juga ke dalam sebuah program analisa energi angin dan sistem konversinya yang dinamakan dengan ???Wind Energy and Conversion System Analysis??? (WECSA)
NUMERICAL ANALYSIS OF IRREGULAR-SHAPED FLOATING BREAKWATER
Get PDFIt is known that the floating type of breakwater is more preferable than conventional or fixed-type one especially by considering its economical and technical benefits. However, the common shape of a floating breakwater, which is usually simply a rectangular shape, could only attenuate waves in a limited range of frequency especially in short wavelength region. In longer wavelength region, it will just move following the seawater motions as a small object. In order to address this problem, an irregular-shaped floating breakwater, which utilizes the relative motion of water inside its body, which as a result could attenuate incoming waves in relatively longer wavelength region, needs to be implemented. By analyzing the relation of hydro dynamical and geometrical influences to the performance, the optimal shape and dimension can be obtained. The performance of the models described by performance index (PI) for clear and convenient comparison and assessment. The analysis and numerical computations based on the potential flow theory
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