1,720,961 research outputs found
Follow the Leader: Alternating CPU/GPU Computations in PDES
No full textDespite the successes of graphics processing units (GPUs) in accelerating simulations in several research fields, their use is largely restricted to domain-specific workloads that consistently offer the large degree of inherent parallelism and computational intensity at which GPUs excel. When targeting generic discrete-event simulations, whose dynamics can vary wildly over time, a static choice between a GPU-based and traditional CPU-based execution is likely to be suboptimal. Here, we explore a parallel discrete-event (PDES) execution scheme for CPU-GPU platforms that aims to approximate an optimal dynamic device choice. Starting from an intermediate model state, a current "leader"device running the simulation is periodically challenged by a brief concurrent run on another device starting from an intermediate model state. Based on the gathered performance measurements, a forecasting scheme determines the leader for the next period. The execution time and power consumption of this scheme hinge on 1) an efficient mechanism for providing the "follower"device with a consistent model state, and 2) robust performance forecasting to justify the device choices. We present these building blocks, their implementation combining the existing CPU and GPU simulators ROOT-Sim and GPUTW, and measurement results demonstrating substantially reduced execution time without increasing energy consumption over a static device choice
Comparing Speculative Synchronization Algorithms for Continuous-Time Agent-Based Simulations
No full textContinuous-time agent-based models often represent tightly-coupled systems in which an agent's state transitions occur in close interaction with neighboring agents. Without artificial discretization, the potential for near-instantaneous propagation of effects across the model presents a challenge to parallelizing their execution. Although existing algorithms can tackle the largely unpredictable nature of such simulations through speculative execution, they are subject to trade-offs concerning the degree of optimism, the probability and cost of rollbacks, and the exploitation of locality. This paper is aimed at understanding the suitability of asynchronous and synchronous parallel simulation algorithms when executing continuous-time agent-based models with rate-driven stochastic transitions. We present extensive measurement results comparing optimized implementations under various configurations of a parametrizable simulation model of the epidemic spread of disease. Our results show that the amount of locality in the agent interactions is the decisive factor for the relative performance of the approaches. Based on profiling results, we identify remaining hurdles for higher simulation performance with the two classes of algorithms and outline potential refinements
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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