1,721,018 research outputs found
A Novel Concurrent Validation Scheme for Hardware Transactional Memory
No full textTransactional memory is a lock-free parallel programming model, which aims at replacing conventional lock-based threaded programming techniques, currently used by multi-core systems. These techniques are difficult to implement and impose unnecessary overheads caused by conservative programming practices. In this thesis, the scalability potential of a transactional memory system, called TMFab, was explored for different numbers of processors and it was concluded that for more than 4 processors the system presents reduced scalability, due to an increase in the validation overhead. In response to this observation, a novel validation scheme was proposed which reduces this overhead, first by allowing multiple transactions to perform their validations and commit operations concurrently, and second by removing the need for broadcasting messages between the active transactions. A distributed shared memory scheme was used to increase the validation and memory access throughput, as well as allow for transactions to commit concurrently on different memory partitions. The two architectures were compared by means of SystemC simulation, and a maximum of 2.5x validation speedup was observed for the modified design, together with a 2.7x reduction in memory access latency. In total, the modified design achieved a maximum execution speedup of 30% over the original, for the benchmarks that were used. Furthermore, the modified system guarantees sequential consistency even in corner case scenarios.Computer EngineeringCircuits and SystemsElectrical Engineering, Mathematics and Computer Scienc
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
Thermal-Aware Design and Runtime Management of 3D Stacked Multiprocessors
No full textThe sustained increase in computational performance demanded by next-generation applications drives the increasing core counts of modern multiprocessor systems. However, in the dark silicon era, the performance levels and integration density of such systems is limited by thermal constraints of their physical package. These constraints are more severe in the case of three-dimensional (3D) integrated systems, as a consequence of the complex thermal characteristics exhibited by stacked silicon dies. This dissertation investigates the development of efficient, thermal-aware multiprocessor architectures, and presents methodologies to enable the simultaneous exploration of their thermal and functional behaviour. Chapter 2 examines the efficiency of multiprocessor architectures from the perspective of the the memory hierarchy, and presents techniques that focus on the effective management and transfer of on-chip data in order to minimize the time spent waiting on memory accesses. In the case of shared-memory multiprocessors, this is achieved through the proposed Persistence Selective Caching (PSC) and CacheBalancer schemes that influence what data is stored in on-chip caches, where it is stored, and for how long. This enables the memory hierarchy to adapt to changing execution behaviour, balance resource utilization, and most importantly, reduce the average latency and energy per memory access. Further to this, Chapter 2 presents the Pronto system, which enables efficient data transfers in message-passing multiprocessors by minimizing the role of the processing element in the management of transfers. Pronto effectively decreases the overheads incurred in setting up and managing data transfers, thereby yielding shorter communication latencies. In addition, it also simplifies the semantics of data movement by abstracting implementation details of communications from the programmer, thus enabling transfers to be specified entirely at the task level. The issue of thermal-aware design for 3D Integrated Circuits (IC) using Nagata’s equation – a mathematical representation of the dark silicon problem – is investigated in Chapter 3. Significantly, the chapter explores the thermal design space of 3D ICs in terms of this equation, and proposes a high-level flow to characterize the specific influence of individual design parameters on thermal behaviour of die stacks. The results of this exploration advance the state-of-the-art by providing new insights into the critical role of power density, thermal conductivity and stack construction in the formation of hotspots in 3D ICs. Building on these insights, the Ctherm framework is proposed for the thermal-aware design of multiprocessor systems-on-chip (MPSoC). Ctherm enables the concurrent evaluation of thermal and functional performance of MPSoCs using automatically generated fine-grained area, latency and energy models for system components, and facilitates the exploration of thermal behaviour early in the system design flow. The efficacy of the framework is demonstrated using a number of practical design cases ranging from floorplanning and temperature sensor placement to application tuning. Together, the characterization and the Ctherm framework further our understanding of the thermal behaviour of die stacks, and provide a practical template for the realization of thermal-aware electronic design automation tooling for 3D ICs. The management of thermal issues that arise in 3D MPSoCs at runtime is examined in Chapter 4. Temperature control is typically exercised by means of Dynamic Thermal Management (DTM) which continuously adapt the activity and power dissipation of system components. A significant disadvantage of state-of-the-art DTMs lies in their inability to account for the non-uniform thermal behaviour of die stacks, leading to the ineffective management of temperatures and in degraded system performance. In Chapter 4, a novel 3D Dynamic Voltage Frequency Scaling (DVFS) scheme is proposed that takes these non-uniformities into account within its power management algorithm, effectively maintains operating temperatures within a safe range, and maximizes system performance within the available thermal margins at individual processing elements. Furthermore, the chapter also presents an adaptive routing strategy to decrease the magnitude of thermal gradients in network-on-chip based 3D architectures, by directing traffic along paths of low temperature. The proposed Immediate Neighbourhood Temperature (INT) adaptive routing scheme actively steers interconnect traffic away from regions with thermal hotspots based only on temperature information available in the immediate neighbourhood, relying on the heat transfer characteristics of 3D ICs to avoid the need for a global temperature monitoring network. The consequent spreading of interconnect activity over multiple paths results in balanced thermal profiles, and decreased operating temperatures across the system. Over the course of these chapters, this dissertation explores the critical issues impeding the realization of thermal-aware 3D stacked multiprocessors, and details a multifaceted approach towards addressing the challenges of dark silicon.Microelectronics - Circuits and SystemsElectrical Engineering, Mathematics and Computer Scienc
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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