133,997 research outputs found
The Bloody Millennium: Internal Conflict in South Asia
No full textThis paper documents the short-term and long-term trends in internal conflict in South Asian countries, using multiple data sources. I find that incidents of terrorism have been rising across South Asia over the past decade, and this increase has been concentrated in economically lagging regions in the post-2001 period. This is in contrast to both the historical patterns of conflict, and the evolution of other types of violence. Analyzing the role of economic, geographic and demographic factors, I find that poorer areas have significantly higher levels of conflict intensity. The paper reviews the various approaches taken by governments to deal with conflict, contrasting security-based approaches with political accommodation and economic approaches. Finally, the paper reviews the potential role of regional cooperation in mitigating conflict.
Essays in corporate financing
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, 1989.Includes bibliographical references.by Lakshmi Shyam-Sunder.Ph.D
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Finding unstable periodic orbits: A hybrid approach with polynomial optimization
No full textWe present a novel method to compute unstable periodic orbits (UPOs) that optimize the infinite-time average of a given quantity for polynomial ODE systems. The UPO search procedure relies on polynomial optimization to construct nonnegative polynomials whose sublevel sets approximately localize parts of the optimal UPO, and that can be used to implement a simple yet effective control strategy to reduce the UPO's instability. Precisely, we construct a family of controlled ODE systems, parameterized by a scalar k, such that the original ODE system is recovered for k=0 and such that the optimal orbit is less unstable, or even stabilized, for k>0. Periodic orbits for the controlled system can often be more easily converged with traditional methods, and numerical continuation in k allows one to recover optimal UPOs for the original system. The effectiveness of this approach is illustrated on three low-dimensional ODE systems with chaotic dynamics
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Replication data for 'Effects of particle precipitation on the polar mesospheric summer echoes observed by EISCAT VHF 224 MHz radar'
No full textThe EISCAT VHF 224 MHz radar data measuring the mesospheric heights and D region ionosphere used in the manuscript 'Effects of particle precipitation on the polar mesospheric summer echoes observed by EISCAT VHF 224 MHz radar' submitted for review are provided herein. The data discussed in the work are collected on 15 - 17 July 2019 and 09 - 10 August 2019. The radar spectrum in the frequency range of -333 to +333 Hz are provided. Also the outputs of optimized Gauss fits made to the spectrum are provided
D. SRI LAKSHMI and KVR SWATHI A NOVEL METHOD FOR SPEED CONTROL OF SWITCHED RELUCTANCE MOTOR BY FUZZY PI CONTROLLER
No full textAbstract: This paper presents a speed control of switched reluctance motor using fuzzy PI controller . Depending on the non linear model of the SRM with negligible mutual inductances and the torque depending on the rotor position of the motor, the subsystems are modeled using MATLAB/SIMULINK . The fuzzyPI controller is robust to sudden changes in reference speed and shows its effect on transient response and decreases the steady state error. This paper provides a better control on the speed of the SRM when compared with conventional PI controller
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