1,721,000 research outputs found
Multi-Criteria Optimization of Real-Time DAGs on Heterogeneous Platforms under P-EDF
Full text linkThis paper tackles the problem of optimal placement of complex real-time embedded applications on heterogeneous platforms. Applications are composed of directed acyclic graphs of tasks, with each DAG having a minimum inter-arrival period for its activation requests, and an end-to-end deadline within which all of the computations need to terminate since each activation. The platforms of interest are heterogeneous power-aware multi-core platforms with DVFS capabilities, including big.LITTLE Arm architectures, and platforms with GPU or FPGA hardware accelerators with Dynamic Partial Reconfiguration capabilities. Tasks can be deployed on CPUs using partitioned EDF-based scheduling. Additionally, some of the tasks may have an alternate implementation available for one of the accelerators on the target platform, which are assumed to serve requests in non-preemptive FIFO order. The system can be optimized by: minimizing power consumption, respecting precise timing constraints; maximizing the applications’ slack, respecting given power consumption constraints; or even a combination of these, in a multi-objective formulation.
We propose an off-line optimization of the mentioned problem based on mixed-integer quadratic constraint programming (MIQCP). The optimization provides the DVFS configuration of all the CPUs (or accelerators) capable of frequency switching and the placement to be followed by each task in the DAGs, including the software-vs-hardware implementation choice for tasks that can be hardware-accelerated. For relatively big problems, we developed heuristic solvers capable of providing suboptimal solutions in a significantly reduced time compared to the MIQCP strategy, thus widening the applicability of the proposed framework.
We validate the approach by running a set of randomly generated DAGs on Linux under SCHED_DEADLINE, deployed onto two real boards, one with Arm big.LITTLE architecture, the other with FPGA acceleration, verifying that the experimental runs meet the theoretical expectations in terms of timing and power optimization goals
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
Support to run-time adaptation by a publish-subscribe based middleware for MPSOC architectures
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Previous issue date: 2019-03-21As aplica??es embarcadas t?m migrado de sistemas baseados em um ?nico processador para uma comunica??o de dados intensiva que exige sistemas multiprocessados. O desempenho exigido por estas aplica??es motivam o uso de arquiteturas multiprocessadas em um ?nico chip (MPSoCs). Mudan?as em tempo de execu??o na qualidade do servi?o prestada pela plataforma MPSoC para as aplica??es motivam a implementa??o de plataformas MPSoCs auto-adaptativas. As plataformas MPSoCs auto-adaptativas empregam sistemas compostos por arquiteturas ricas em sensores-atuadores que observam as mudan?as no ambiente de execu??o e adaptam o sistema balanceando dinamicamente m?ltiplos objetivos em v?rios n?veis de arquitetura. Esses sistemas auto-adaptativos requerem modelos de comunica??o/programa??o bem adaptados ? caracter?stica distribu?da do ambiente para coordenar a comunica??o entre os elementos que o comp?em. Esta Tese investiga os atuais modelos de programa??o/comunica??o em MPSoC e outros dom?nios correlatos com rela??o ao acoplamento entre os elementos comunicantes e a infraestrutura de hardware e software adjacente. A hip?tese levantada ? que ? necess?rio usar um modelo que, al?m de abstrair a complexidade da comunica??o, tamb?m forne?a um acoplamento mais flex?vel entre os elementos comunicantes do sistema auto-adaptativo. Adicionalmente, n?s argumentamos que as abordagens atualmente utilizadas para incorporar sistemas auto-adaptativos em plataformas MPSoCs seguem uma metodologia de desenvolvimento n?o sistematizada, o que impacta na qualidade de software relacionada ao reuso de c?digo e manutenabilidade. Sendo assim, esta Tese prop?e aplicar o modelo publish-subscribe em uma abordagem de desenvolvimento baseada em middleware visando melhorar a qualidade do software de sistemas auto-adaptativos enquanto minimiza impactos indesejados da abordagem proposta sobre o sistema. A Tese ? suportada atrav?s de um estudo de caso em que implementamos um sistema auto-adaptativo utilizando a abordagem proposta e comparamos os resultados com um sistema auto-adaptativo base, de acordo com m?tricas de desempenho, energia e qualidade do software. Os resultados mostram que o modelo empregado em uma abordagem de desenvolvimento baseada em middleware melhorou a qualidade do software do sistema autoadaptativo de 33% at? 47.8%, dependendo da m?trica avaliada, com um reduzido overhead em rela??o ? m?tricas de desempenho (4.5%) e energia (5.9%). Mostramos tamb?m que os requisitos para o middleware s?o adequados para plataformas MPSoCs caracterizadas por restri??es de uso de mem?ria.Embedded applications have been migrating from single processor-based systems to intensive data communication requiring multi-processing systems. The performance demanded by applications motivate the use of Multi-Processor System-on-Chip (MPSoC) architectures. Run-time changes in the quality of service provided by the MPSoC platform to the applications motivate the implementation of self-adaptive MPSoC platforms. Self-adaptive MPSoC platforms employ systems composed of sensor-actuator rich architectures that observe the changes in the execution environment and adapt the system dynamically balancing the multiple objectives across multiple architecture levels. These self-adaptive systems require communication/programming models well suited to the distributed characteristic of the environment in order to coordinate communication between the elements that compose it. This Thesis investigates current programming/communication models on MPSoC and other correlated domains regarding the coupling between the communicating elements and the adjacent hardware and software infrastructure. The hypothesis raised is that it is necessary to use a model that, besides abstracting the communication complexity, provides a more flexible coupling between the communicating elements of the self-adaptive system. Additionally, we argue that the current approaches used to incorporate self-adaptive systems in MPSoC platforms follow a non-systematic development methodology, which impacts the quality of software related to code reuse and maintainability. Therefore, this Thesis proposes to apply the publish-subscribe model in a middleware-based development approach to perform the communication employed between the elements of a self-adaptive MPSoC platform and to improve software quality of self-adaptive systems while minimizing undesired impacts of the proposed approach on the system. The Thesis is supported through a case study where we implement a self-adaptive system following the proposed approach and compare the results with a baseline self-adaptive system according to performance, energy and software quality metrics. The results show that the proposed model employed on a middleware based development approach has improved the software quality of the self-adaptive system by 33% to 47.8%, depending on the metrics evaluated, with a reduced overhead regarding metrics of performance (4.5%) and energy spent (5.9%). We also show that the requirements for middleware are suitable for MPSoC platforms with memory usage constraints
Otimiza??o e an?lise de algoritmos de ordenamento de redes proteicas
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Previous issue date: 2014-02-25Analysis by Transcriptogram was developed as a solution to noise reduction, usually present in the microarray measuring technique of the Transcriptome, and has demonstrated potential to be applied as a method of disease diagnostics. The noise reduction in the measure is achived by the protein interaction network ordering, allowing gene expression analysis in whole genome scale. The Transcriptogram's efficiency to noise reduction was analyzed, however, it still lacks an analisys of the ordering quality, so that the best parameter setting for the ordering algorithm is used by the Transcriptogram. So far, this analysis is hindered by the high runtime of the ordering algorithm. In this work, an analysis of the ordering algorithm stages allows some optimizations, and consequent reduction in execution time, also allowing further analysis on which parameters settings have the greatest influence on the ordering quality. Applying the Transcriptogram to a diagnostic problem, the diagnostic measure is used to characterize the influence of the parameters of the ordering algorithm to achive better diagnoses. The results show that the protein network used in previous works doesn't produce the best diagnostics. Moreover, the ordering minimization, achieved by executing the ordering algorithm for longer periods, does not necessarily increase the probability to find better diagnosis compared to random ordering. Eventhough the experimental diagnostic results could not statistically difFerentiate random ordering from optimized ordering, these results cannot be considered conclusive since a single disease has been evaluated.A an?lise por Transcriptograma foi desenvolvida como uma solu??o para a redu??o de ru?do, comum nas medidas do Transcriptoma provenientes da t?cnica de microarranjo, e tem demonstrando potencial se aplicada como m?todo para diagn?sticos de doen?as. A redu??o do ru?do existente nas medidas se d? pelo ordenamento da rede de intera??es proteicas do organismo, permitindo a an?lise da express?o g?nica em escala de genoma completo. A efici?ncia do Transcriptograma para a redu??o do ru?do j? foi analisada, entretanto, ainda carece a avalia??o da qualidade do ordenamento, definindo para isso, amelhor configura??o de par?metros para o algoritmo de ordenamento utilizado pelo Transcriptograma. At? o momento, essa an?lise ? dificultada pelo elevado tempo de execu??o do algoritmo de ordenamento. Neste trabalho, uma an?lise das etapas do algoritmo de ordenamento possibilita a realiza??o de otimiza??es, e consequente redu??o no tempo de execu??o, al?m de permitir a an?lise mais aprofundadadas configura??es dos par?metros que tem maior influ?ncia na qualidade do ordenamento. Aplicando o Transcriptograma a um problema de diagn?stico, utiliza-se a medida do diagn?stico para caracterizar a influ?ncia dos par?metros do algoritmo de ordenamento na obten??o de melhores diagn?sticos. Observa-se nos resultados, que a rede proteica utilizada em trabalhos anteriores n?o apresenta os melhores diagn?sticos. Al?m disso, a minimiza??o do ordenamento, alcan?ada por meio da execu??o prolongada do algoritmo de ordenamento, n?o necessariamente aumenta a probabilidade de encontrar um melhor diagn?stico comparado com o ordenamento aleat?rio. Mesmo que os resultados experimentais com o diagn?stico n?o diferenciem estatisticamente o ordenamento aleat?ria do ordenamento otimizado, estes resultados n?o podem ser considerados conclusivos pois uma ?nica doen?a foi avaliada
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
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