1,721,308 research outputs found
AXIOM: a scalable, efficient and reconfigurable embedded platform
No full textCyber-Physical Systems (CPSs) are becoming widely used in every application that requires interaction between humans and the physical environment. People expect this interaction to happen in real-time and this creates pressure onto system designs due to the ever-higher demand for data processing in the shortest possible and predictable time. Additionally, easy programmability, energy efficiency, and modular scalability are also important to ensure these systems to become widespread. All these requirements push new scientific and technological challenges towards the engineering community. The AXIOM project (Agile, eXtensible, fast I/O Module), presented in this paper, introduces a new hardware-software platform for CPS, which can provide an easy parallel programming model and fast connectivity, in order to scale-up performance by adding multiple boards. The AXIOM platform consists of a custom board based on a Xilinx Zynq Ultrascale+ ZU9EG SoC including
four 64-bit ARM cores, the Arduino socket and four high-speed (up to 18 Gbps) connectors on USB-C receptacles. By relying on this hardware, DF-Threads, a novel execution model based on
dataflow modality, has been developed and tested. In this paper, we highlight some major conclusions of the AXIOM project, such as the gain in performance compared to other parallel programming models such as OpenMPI and Cilk
Analyzing the Impact of Operating System Activity of different Linux Distributions in a Distributed Environment
No full textA rise in the number of threads in large-scale applications running on multi-node architectures makes operating system activity increasingly more relevant. Therefore, evaluation methodologies need to account for these activities. We decided to build our evaluation environment through the COTSon simulator. Moreover, our environment permits flexible Design Space Exploration (DSE) by making easy the management of many experiments and the characterizations of Operating System (OS) activity. In this paper, we show the result analysis tool flow and the OS impact of different Linux distributions running on a distributed environment consisting of several nodes with a full OS. In order to quantify our results, we use matrix multiplication benchmark executed through a DataFlow model, named DataFlow Threads(DF-Threads). We analyze key metrics like L2 cache miss rate, execution cycles, data access latency, and kernel cycles showing up to 60% performance variations among the different OS distributions
A Novel High-Isolation Resistor-Less Millimeter-Wave Power Divider Based on Metamaterial Structures for 5G Applications
No full textIn this article, a simple and effective method based on the metamaterial concept is proposed to achieve very high isolation between the output ports of a millimeter-wave power divider (MWPD). The proposed MWPD is designed for use in 5G applications (28-32 GHz). In order to increase the isolation, three metamaterial rows are used, each row containing eight proposed unit cells. These metamaterial unit cells are loaded between two dielectric layers. By using this method and without isolating resistors, isolation is improved by more than 36 dB, as compared with a prototype power divider in which no metamaterial element was used. The maximum measured isolation is 43 dB at 30 GHz. The final dimensions of the proposed MWPD are 8 x 8 x 0.582 mm(3) or 0.9 lambda(g) x 0.9 lambda(g) x 0.08 lambda(g) where lambda(g) is the guided wavelength at 30 GHz. The simplicity of design, its compactness, and most importantly, high isolation between output ports without any lumped resistor are the key advantages of the proposed MWPD
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
A design space exploration tool set for future 1K-core high-performance computers
No full textGiven the constantly growing complexity of multi-core architectures, Design Space Exploration (DSE) tools play an important role to evaluate different design options. In this paper, we present a DSE toolset targeting massively parallelized HW/SW architectures with a high degree of flexibility in order to successfully simulate multi-core-multi-node platforms. Our DSE tools provide a rapid and simple-to-use work-flow to easily retrieve and analyze the key metrics and eventually evaluate the design. We examine the DSE toolset and methodology while performing several simulations of a
general purpose 1K-core architecture and evaluate not only standard metrics like the L2 cache miss rates, but also operating system activity and its impact. We leverage the knowledge gained in our methodology to develop and evaluate a novel dataflow execution model named “DataFlow-Threads” (DF-Threads). We validated the outcomes of the simulator against an equivalent FPGA-based design
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
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