1,720,961 research outputs found
Thermal-aware scheduling in green data centers / Muhammad Tayyab Chaudhry
No full textData centers can go green by saving electricity in two major areas: computing and cooling. Servers in data centers require a constant supply of cold air from on-site cooling mechanism for reliability. Increased computational load makes servers to dissipate more power as heat and eventually amplifies the cooling load. In thermal-aware scheduling, computations are scheduled with the objective of reducing data center wide thermal gradient, hotspots and cooling magnitude. Complemented by heat modeling, thermal-benchmarking, thermal-aware server arrangement; and thermal-aware monitoring and profiling, this scheduling is energy efficient and economical.
This research work proposes multiple techniques for thermal-benchmarking of data center servers such as: Thermal-benchmarking for Standalone Servers (TBSS), Thermal-benchmarking for Server Comparison (TBSC), Multi-intensity TBSS (MiTBSS) and Thermal-benchmarking for Virtualized Clusters (TBVC). These techniques are useful for thermal evaluation of servers, emulating various types of workloads and creating the thermal profiles. A thermal-aware server relocation algorithm (ThSRA) for thermal-stress free arrangement of servers is also proposed. The experimental results show that the peak outlet temperatures of the servers can be brought closer to average outlet temperature by over 5 times through ThSRA. This also brings the lowering of average peak outlet temperature by 3.5% and minimizing the thermal-stress.
Thermal profiles are used for outlet temperature prediction modeling of the servers. These models include the worst case prediction model (WCPM), optimistic prediction model (OPM) and enhanced optimistic prediction model (EOPM). The best prediction model can predict the outlet temperature of the servers with an average error of up to 0.3 degree Celsius. WCPM is applied for offline hotspot-resistant virtual machine deployment algorithm (HVMDA) and hotspot-aware server arrangement algorithm (HSLERA). The combination of HVMDA and HSLERA leads to increase in server utilization by up to 50% and lowering the peak outlet temperature by up to 3% on average. The WCPM and OPM are used for the implementation of online thermal-aware VM scheduling. These schedulers have comparatively lower thermal-gradient across all servers, lower outlet temperatures across all servers, effective use of computing capacity and the power consumption. The proposed proactive schedulers comparatively show up to 11% in total energy savings. All these thermal-aware techniques are helpful in the establishment of green data centers
Software Transactional Memory for Graphics Card
No full textThe introduction of CUDA, NVIDIA's system for general purpose computing on their many-core
graphics processor system, and the general shift in the industry towards parallelism, has created a
demand for ease of parallelization. Software transactional memory (STM) simplifies development of
concurrent code by allowing the programmer to mark sections of code to be executed atomically. The
STM will then guarantee that other processes will see either none or all of the writes done in in that
section. In contrast to using locks, STM:s are easy to compose and does not suffer from deadlocks. An STM can thus be seen as a concurrency control mechanism
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
Towards a Software Transactional Memory for Graphics Processors
No full textThe introduction of general purpose computing on many-core graphics processor systems, and the general shift in the industry towards parallelism, has created a demand for ease of parallelization. Software transactional memory (STM) simplifies development of concurrent code by allowing the programmer to mark sections of code to be executed concurrently and atomically in an optimistic manner. In contrast to locks, STMs are easy to compose and do not suffer from deadlocks. We have designed and implemented two STMs for graphics processors, one blocking and one non-blocking. The design issues involved in the designing of these two STMs are described and explained in the paper together with experimental results comparing the performance of the two STMs.Eurographics Symposium on Parallel Graphics and Visualizatio
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