1,720,984 research outputs found
Memory Performance of Public-Key cryptography Methods in Mobile Environments
No full textAs an increasing number of Internet hosts are wireless C handheld devices with small memory and strict CPU-latency constraints C the performance of cryptography methods has become critical for high transaction throughput. Elliptic Curve Cryptography 8ECC 9 is emerging as an attractive public-key system for constrained environments C because of the small key sizes and computational efficiency C while preserving the same security level as the standard methods. The memory performance of ECC algorithms was scarcely investigated.DAWe have developed a set of kernel benchmarks to examine performance of standard and corresponding elliptic curve public-key methods. In this paper C we characterize the operations and their memory impact on performance in Diffie-Hellman key exchange C digital signature algorithm C ElGamal C and RSA public-key cryptosystem C as well as elliptic curve Diffie-Hellman key exchange C elliptic curve digital signature algorithm and elliptic curve El-Gamal algorithm. DAWe modeled a typical mobile device based on the Intel XScale architecture C which utilizes an ARM processor core and studied the benchmark set on that target. Different possible variations for the memory hierarchy of such basic architecture were considered. We compared our benchmarks with MiBench FSecurity C another widely accepted benchmark set C in order to provide a reference for our evaluation
Tiled Architectures & Recent Proposals for Chip Multiprocessors
No full textHow to effectively use the increasing number of transistors available on a single chip while avoiding the wire delay problem? This is one of the most interesting research questions for the microarchitecture community. We have finally arrived at the point where the time needed for signals to reach the opposite edge of a chip is becoming longer than one cycle. This leads to the impossibility of gaining performance improvements via the scaling of superscalar architectures. One possible solution for using the available transistors efficiently and effectively, while hiding wire delay as much as possible is to parallelize resource usage through resource clustering and decoupling. For example, using on chip multiprocessor architectures is the most natural way to increase performance beyond what we can obtain from a single processor core. A generalization of this concept has led to several solutions for chip multiprocessors. The focus of this paper is to review some recent proposals that employ the clusterization/tiling paradigm, at different extents, in a comparative fashion, and highlight their main features and advantages. Recently, a good number of tiled/clustered architectures have been proposed, indicating that this field is gathering high interest from both academia and industry: WaveScalar (University of Washington), TRIPS (University of Texas at Austin), Smart Memories (Stanford University), Synchroscalar (University of California, Davis and California Polytechnic State University, San Luis Obispo), Raw (MIT), CODE (Stanford University), SCALE (MIT). Even if such proposals adopt a resource tiling approach to implement chip multiprocessors, several other approaches make use of multithreading, dataflow ISA, vectorization and clustering to overcome the limitations of simple symmetric multiprocessor (SMP) design
Elliptic Curve Cryptography support for ARM based Embedded systems
No full textElliptic Curve Cryptography (ECC) is emerging as an attractive approach to public-key cryptography for constrained environments, because of the small key sizes and computational efficiency, while preserving the same security level as the standard methods. The performance of public-key cryptography methods is critical in embedded environments such as applications for wireless, handheld internet devices and smartcards with small memory and strict CPU-latency constraints. Power control is also important for embedded systems as well as security against Differential Power Analysis (DPA). We examined the performance of a set of ECC kernel benchmarks and proposed ISA extensions to support secure and efficient execution, on a ARM processor, which is a very common platform for embedded system applications. An evaluation of possible ARM instruction set extension for Elliptic Curve Cryptography over binary finite fields GF(2m) is presented. With almost no cost at hardware level, we found an average 33% reduction of the total number of dynamically executed instructions. Finally, we analyzed the power requirement to achieve an efficient and secure execution from a power standpoint. Some preliminary results showing the power consumption of the benchmarks are presented
Emulazione vocale del mouse per soggetti con disabilità motoria
No full textIl compito di comunicare con il computer attraverso i più comuni dispositivi di ingresso è molto difficile per gli utenti portatori di alcune tipologie di handicap fisici. Per questo, abbiamo pensato di realizzare un dispositivo che permette di controllare il puntatore in una comune interfaccia a finestre tramite la voce, utilizzando un protocollo di adattamento al contesto grafico per rendere l’interazione più immediata
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
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