1,721,281 research outputs found
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
Performance evaluation of transmit diversity techniques in the CDMA 2000 standard
Full text linkThesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 123).This thesis evaluates the performance of two forward-link transmit diversity techniques in the CDMA2000 standard: Space-Time Spreading (STS) and Phase-Sweep Transmit Diversity (PSTD). For each technique, the evaluation consists of conducting 9.6 kbps Markov calls in the field and measuring the mean forward-link fundamental-channel (F-FCH) transmit power required to achieve a 1% frame error-rate (FER) at the mobile receiver. The required transmit power is used to compute an estimate of cell capacity as measured by the number of supported users, assuming a fixed total transmit power at the base station. It is observed that enabling STS increases capacity by up to 80% if all mobiles support STS, but capacity is reduced by up to 20% when fewer than 35% of the mobiles support the technique. The capacity loss results from interference of the diversity-antenna signal on mobiles that do not support STS; such interference causes an F-FCH transmit power increase of up to 1.5 dB in multipath Rayleigh-faded channels, as observed in lab experiments. PSTD, which does not require mobile-specific support, was found to improve cell capacity by 12% according to the field experiments.by Murali S. Vajapeyam.M.Eng
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
NoC topology synthesis for supporting shutdown of voltage islands in SoCs
No full textIn many Systems on Chips (SoCs), the cores are clustered in to voltage islands. When cores in an island are unused, the entire island can be shutdown to reduce the leakage power consumption. However, today, the interconnect architecture is a bottleneck in allowing the shutdown of the islands. In this paper, we present a synthesis approach to obtain customized application-specific Networks on Chips (NoCs) that can support the shutdown of voltage islands. Our results on realistic SoC benchmarks show that the resulting NoC designs only have a negligible overhead in SoC active power consumption (average of 3%) and area (average of 0.5%) to support the shutdown of islands. The shutdown support provided can lead to a significant leakage and hence total power savings
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
Comparative Analysis of NoCs for Two-Dimensional Versus Three-Dimensional SoCs Supporting Multiple Voltage and Frequency Islands
No full textIn many of today’s system-on-chip (SoC) designs, the
cores are partitioned into multiple voltage and frequency islands
(VFIs), and the global interconnect is implemented using a packetswitched
network on chip (NoC). In such VFI-based designs,
the benefits of 3-D integration in reducing the NoC power or
delay are unclear, as a significant fraction of power is spent in
link-level synchronization, and stacked designs may impose many
synchronization boundaries. In this brief, we show the quantitative
benefits of the 3-D technology on NoC power and delay values
for such application-specific designs. We show a design flow for
building application-specific NoCs for both 2-D and 3-D SoCs with
multiple VFIs. We present a detailed case study of NoCs designed
using the flow for a mobile platform. Our results show that power
savings strongly depend on the number of VFIs used (up to 32%
reduction). This motivates the need for an early architectural
space exploration, as allowed by our flow. Our experiments also
show that the reduction in delay is only marginal when moving
from 2-D to 3-D systems (up to 11%), if both are designed
efficiently
A method to remove deadlocks in Networks-on-Chips with Wormhole flow control
No full textNetworks-on-Chip (NoCs) are a promising interconnect paradigm to address the communication bottleneck of Systems-on-Chip (SoCs). Wormhole flow control is widely used as the transmission protocol in NoCs, as it offers high throughput and low latency. To match the application characteristics, customized irregular topologies and routing functions are used. With wormhole flow control and custom irregular NoC topologies, deadlocks can occur during system operation. Ensuring a deadlock free operation of custom NoCs is a major challenge. In this paper, we address this important issue and present a method to remove deadlocks in application-specific NoCs. Our method can be applied to any NoC topology and routing function, and the potential deadlocks are removed by adding minimal number of virtual or physical channels. Experiments on a variety of realistic benchmarks show that our method results in a large reduction in the number of resources needed (88% on average) and NoC power consumption, area reduction (66% area savings on average) when compared to the state-of-the-art deadlock removal methods
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