1,720,983 research outputs found
All-digital control-theoretic scheme to optimize energy budget and allocation in multi-cores
Full text linkThe Internet-of-Things (IoT) revolution fueled new challenges and opportunities to achieve computational efficiency goals. Embedded devices are required to execute multiple applications for which a suitable distribution of the computing power must be adapted at run-time. Such complex hardware platforms have to sustain the continuous acquisition and processing of data under severe energy budget constraints, since most of them are battery powered. The state-of-the-art offers several ad-hoc contributions to selectively optimize the performance considering aspects like energy, power, thermal or reliability. However, there is a need for a generic coordinated management strategy able to cope with all of these dimensions, while allowing the Operating System (OS) and the applications to “suggest” or constrain the actuation. This paper proposes a unified control-theoretic scheme to coordinate the design of energy-budget and energy allocation solutions for multi-cores. The proposed controller can work with any actuator and it can interact, at run-time, with both the applications and the OS to optimize the actuation signals steering the computing platform. Such control scheme offers the possibility to integrate any performance related policy in the form of an energy-allocation strategy, still ensuring the theoretic exponential stability of the overall controller if the actuation of the policy, coming from the OS and the applications, “is not too fast”. To demonstrate the feasibility of our solution, we implemented the controller into a RISC multi-core running on the Xilinx Artix 100t FPGA device, available in the the Digilent Nexys4-DDR board. Results considering two actuators and both the quad- and the eight-core version of the considered computing platform, highlight the scalability of the proposed solution as well as an area overhead for the –all digital, on chip– controller limited to 0.86% (FFs) and 5.3% (LUTs) of the FPGA chip. We also considered a dynamic scenario validating the speed of the controller, where our framework has to face with modifications to the energy-allocation control policy carried out by the OS and the applications. The obtained results are collected by executing a huge mix of benchmarks and the statistical significance is accounted by executing each scenario 30 times. Such results are analyzed considering three quality metrics. First, the efficiency in exploiting the imposed budget (EFFg) that is on average 98.27%. Second, the overflow of the actual average power consumption with respect to the assigned budget (OV Fg), which is limited to 1.43 mW on average. Last, the performance utility loss due to the control scheme that is limited to 1.87% on average
Design of side-channel resistant power monitors
Full text linkIn modern computing platforms, power monitors are employed to deliver online power estimates to support different run-time power-performance optimization methodologies. However, the possibility of setting up a successful side-channel attack by analyzing the power estimates imposes the use of a suitable and systematic approach in the design of such power monitors. This paper proposes a design methodology to automatically identify and implement side-channel resistant power monitors at the hardware level, for generic computing platforms. The methodology works by designing a power monitor for which the switching activity of the signals used to compute the power estimates is not a function of both the secret key and the plaintext/ciphertext values processed by the computing platform. According to the most recent standardized methodologies to assess the side-channel security, our experimental validation leverages both CPA and t-test analysis considering a general purpose System-on-Chip executing different cryptographic primitives and an application-specific accelerator implementing the AES-128 algorithm. Our results confirm the impossibility of retrieving the secret key from the power estimates provided by our side-channel resistant power monitor. Considering several temporal resolutions, we highlight an accuracy error of the power estimates limited to less than 2.7%, as well as an average area and power overheads for the protected power monitors lower than 6% and 5%, respectively. To this end, the proposed methodology is able to deliver a side-channel resistant power monitor within state-of-the-art accuracy error and overheads
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
DENA: A DVFS-Capable Heterogeneous NoC Architecture
No full textThe current design drivers for multi-cores, namely performance per watt, scalability and flexibility, make the Networks-on-Chip (NoCs) the de-facto on-chip interconnect. State of the art NoCs can exploit heterogeneous solutions and complex DVFS techniques to fulfill also the variability of the application requirements. Relevant showstoppers to the design of a truly flexible NoC fitting all the possible traffic conditions, are the burstiness of the traffic generated by modern applications magnified by the unbalanced usage of the interconnect resources due to the implemented coherence protocol. This paper presents DENA, a DVFS-capable, heterogeneous NoC design, encompassing the coherence protocol, the application behavior and the need to minimize the energy budget. Simulation results on a 64-core, 2D-mesh architecture executing the SPLASH2 benchmark suite, testify the advantages of DENA from both the performance and energy viewpoints with an average 34.3% energy-performance improvement against the state of the art DVFS-capable NoC design
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
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