1,720,963 research outputs found
Hemivariational continuum approach for granular solids with damage-induced anisotropy evolution
No full textMechanical behavior of materials with granular microstructures is confounded by unique features of their grain-scale mechano-morphology, such as the tension–compression asymmetry of grain interactions and irregular grain structure. Continuum models, necessary for the macro-scale description of these materials, must link to the grain-scale behavior to describe the consequences of this mechano-morphology. Here, we consider the damage behavior of these materials based upon purely mechanical concepts utilizing energy and variational approach. Granular micromechanics is accounted for through Piola’s ansatz and objective kinematic descriptors obtained for grain-pair relative displacement in granular materials undergoing finite deformations. Karush–Kuhn–Tucker (KKT)-type conditions that provide the evolution equations for grain-pair damage and Euler–Lagrange equations for evolution of grain-pair relative displacement are derived based upon a non-standard (hemivariational) variational approach. The model applicability is illustrated for particular form of grain-pair elastic energy and dissipation functionals through numerical examples. Results show interesting damage-induced anisotropy evolution including the emergence of a type of chiral behavior and formation of finite localization zones
비압축성 나비에-스토크스 방정식의 GPGPU 구현을 위한 semi-implicit 레드/블랙 solver
No full text학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2013. 8. 성원용.푸아송 방정식을 위한 레드/블랙 접근 방법에서 착안된 새로운 반-내
포의 이색 나 비에 스토크스 방정식이 GPGPU를 활용한 비압축성 유
체 시뮬레이션을 위해 연 구되었다. 이 방법은 극도로 불안정한 유체
흐름을 시뮬레이션 하는 경우에 특히 효과적이라는 것이 입증된 바 있
다. 또한 이 방법은 안정조건에 여유가 있기 때문 에, 시간 간격을 선택 하는데 있어 더 큰 자유도를 제공한다는 장점이 있다. 공간 적 이산은 엇갈림격자를 사용하고, 대류에 의해 결정되는 흐름을 관찰하기 위해
WENO 방법을 사용하여 대류항을 근사한다. 이 연산에 지배적인 영
향을 주는 것 은 행렬을 사용하지 않는 전처리된 켤레구배법(Preconditioned Conjugate Gradient) 알고리즘을 사용하는 푸아송 방정식 풀이 방 식이다. 이미 알려진 행렬 을 사용하지 않는 여러 전처리 조절방법들이 고려되었다. 레드/블랙 SSOR은 일반 적으로 주 풀이방법으로 사용되
지만,행렬을 사용하지 않는 PCG의 전처리 조절방 법 중 가장 적합한
방법인 것으로 밝혀졌다. 명시적인 PCG의 재시작을 이용한 혼 합 정
밀도 조정은 불안정한 구간에서 약간의 이득을 주지만, 안정적인 구간
에서는 불이익을 준다. 보다 나은 성능의 최적화를 위해 풀이 방법의
감도에 대한 연구가 수행되었다.A novel Semi-Implicit Bicolor Navier-Stokes solver, inspired by red/black scheme for Poisson equation, was developed for simulating incompressible fluids on GPGPU. The solver was shown to be beneficial for simulating highly unsteady flows. Also, it allows more freedom in choice of time step because of the relaxed stability condition. Spatial discretization uses staggered grid and approximates convective terms with WENO scheme to capture the effects of convection-dominated flows. The computation is dominated by the Poisson solver, which uses matrix-free Preconditioned Conjugate Gradient algorithm. Several known matrix-free preconditioners were considered. Red/Black SSOR was found to be the most suitable matrix-free preconditioner for PCG, even though it is usually used as a main solver. A mixed precision modification with explicit restarts of the PCG was shown to be slightly beneficial in unsteady region, while giving a negative effect for steady flow. Sensitivity analysis of the solver was carried for further performance optimization.Maste
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
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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