177,041 research outputs found
Congestion pricing for dynamic bandwidth allocation in satellite networks: A game-theoretic approach
No full textThe purpose of this work is to provide an enhanced adaptive approach to classic queue-based Bandwidth-on-Demand (BoD) procedures in broadband satellite networks. In queue-based schemes, the controller's objective is to drive the buffer queue length to an appropriate reference queue length, and the efficiency of the control strictly depends on the choice of its reference value. In latest approaches, solutions to adaptively modify the target reference queue length based on a set of network information have been proposed; nevertheless, in such approaches, the satellite terminals should base their control strategies on information which are not available to them, according to the communication standards of state-of-the-art technologies, such as DVB-RCS. The novelty of the presented algorithm is that it overcomes this limit by dynamically changing the reference queue length, based on information actually broadcast to the network terminals; the algorithm is at same time simple and effective, and is based on a game-theoretic approach which benefits of recent advances in congestion pricing theory. The effectiveness of the proposed approach is supported by Opnet (R) simulations as well as by considerations about the real implementability of the solution
Low-dose CT protocol for orthodontic diagnosis.
No full textAIM: This was to correlate the dosimetric evaluation with high diagnostic
accuracy by suggesting a protocol that significantly reduces the dose
administered by a Dentascan exam without affecting diagnostic accuracy.
MATERIALS AND METHODS: 17 patients were selected consecutively (7 males and 10
females) of a mean age of 11.2 (8-14 years) who sought orthodontic treatment.
They needed CT control before and after treatment with RME to evaluate impacted
canines. The study was performed using a multidetector 16-rows CT with two
protocols that provided 2 different KV acquisition parameters: 80 KV or 120 KV.
Radiation dose was evaluated in two ways: CTDI and DLP. Image quality was rated
and the results were compared to identify significant differences in terms of
image quality, radiation exposure and presence of artefacts.
RESULTS: The 80 KV scanning has a significantly lower effective radiation dose
compared to the 120 KV scanning (p <0.05). The images of all patients were used
for comparing the protocols in terms of image quality. The mean scores for the 80
KV scanning images were 4.18 +/-0.81 and 4.41 +/-0.80 for dose obtained by 120 KV
scanning. The median image quality was 4 (good) for both protocols. The 80 KV
protocol allowed, as well as the 120 KV, a careful analysis by the orthodontist
and the dental surgeon that together, based on this images, can choose the best
line of treatment between several available options.
CONCLUSION: 80 KV protocols compared with 120 KV protocols resulted in reduced
total radiation dose without relevant loss of diagnostic image information and
quality. The images were good enough to obtain information about the exact
position of impacted teeth and to plan the best line of surgical treatment and
mechanotherapy strategy
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Securing cyber-physical systems: An optimization framework based on OSSTMM and genetic algorithms
No full textThis paper presents an optimization framework, based on Genetic Algorithms, for the control of the 'security level' of a Cyber-Physical System (CPS). The security level is a quantity that has been studied in several industrial standards, among which we selected the Open Source Security Testing Methodology Manual (OSSTMM). The proposed optimization solution is validated on scenarios representative of real operations of a security evaluator, and numerical simulations report the performances obtained by the algorithm
"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.
Diagnostic evaluation of a case of lingual thyroid ectopia
No full textAbstractThyroid ectopia can occur when the process of thyroid embryogenesis fails. Here, we present the case of a 30-year-old woman with thyroid ectopia that was discovered during magnetic resonance imaging of cervical spine for referred neck pain. Imaging revealed the presence of an encapsulated mass at the base of her tongue. The patient was not symptomatic for any compression of the airways. Diagnosis of ectopic lingual thyroid was confirmed by 99mTC scintigraphy. Incidental diagnosis of thyroid ectopia in asymptomatic adult patients is rare, and it should be considered on diagnostic imaging in case of an anterior midline cervical mass
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
Letter from R. R. Zellick, Assistant Trust Officer, Anglo California National Bank of San Francisco, to Joseph R. Goodman, October 2, 1942
No full textLetter from R. R. Zellick, Assistant Trust Officer at The Anglo California National Bank of San Francisco, to Joseph R. Goodman, regarding property owned by Dave Tatsuno. Zellick mentions a dispute between current tenants and Tatsuno, and that Tatsuno has asked Goodman to help locate trustworthy tenants.Personal correspondence, organizational records, government documents, publications, and other papers created or collected by Joseph R. Goodman documenting the forced removal and incarceration of Japanese Americans during World War II, as well as organized resistance to incarceration. Included in the collection are records of the Japanese Young Men's Christian Association and the Japanese American Citizens' League in San Francisco, including papers of the Japanese YMCA's executive secretary Lincoln Kanai; Sakai family papers; Goodman's correspondence to and from Japanese American incarcerees, organizations opposing forced removal and incarceration of Japanese Americans, the War Relocation Authority, and others; publications, photographs, and ephemera from the Topaz Relocation Center, where Goodman taught high school; War Relocation Authority records and publications; and newspaper clippings, pamphlets, and reports about forced removal and incarceration created by various government, religious, and civic organizations, in California and nationwide
Whole body 16-row multislice CT in emergency room: Effects of different protocols on scanning time, image quality and radiation exposure
No full textThe objective of this study was to compare two different scanning protocols in patients suspected to have multiple trauma using multidetector 16-row computed tomography (CT) to better define scanning time, imaging quality and radiation exposure. Forty-six patients, between March 2004 and March 2005, with suspected multiple trauma (cerebral, spine, chest, abdominal and pelvis) were evaluated with two different protocols: Protocol "A" 26 patients; Protocol "B" 20 patients. Protocol A consists of a single-pass continuous whole-body acquisition (from vertex to pubic symphysis), whereas Protocol B of conventional segmented acquisition with scanning of body segments individually. Both protocols were performed using a multidetector 16-rows CT (Light-Speed 16, General Electric Medical System, Milwaukee, WI, USA) with the same technical factors. Radiation dose was evaluated in two ways: computer tomography dose index (CTDI) = dose measured in central and peripheral region of the subjects as a direct result of a CT section acquisition of T millimeters thick (independent from the two protocols) and dose length product (DLP) = total dose deposited over the length of the acquisition (dependent from the two protocols). Image quality was rated according to the following scores: 1, excellent; 2, good; 3, satisfactory; 4, moderate and 5, poor. The results were compared using Wilcoxon's test to identify significant difference in terms of image quality, scanning time, radiation exposure and presence of artifacts, assuming significance at a p value of <0.05. In the single-pass scanning, DLP was 2.671 mGy x cm and a total scan time of 35 s. In whole-body protocols, we have seen artifacts due to arm adduction in thorax and less image quality in brain. In the conventional segmented study, DLP was 3.217 mGy x cm and a total scan time of 65 s; this protocol offered less extraction capabilities of off-axial on focused images of the entire spine, aorta, facial bones or hip without rescanning. Protocol A revealed a significant decrease in scan time (35 vs 65 min, p < 0.05), time in the CT examination room (21.7 vs 31.6 min.; p < 0.05), and final image analysis (83.7 vs 102.9 min; p < 0.05) and radiation dose compared to protocol B (p < 0.05). No significant difference was found for patient transport time, image reconstruction time and imaging quality. Reconstruction and isotropic reformation of axial image acquired by whole-body, single-pass protocols due to entire spine evaluation, aortic and splanchnic CT angiography eliminate additional studies. The whole-body, single-pass protocols, compared with segmented acquisitions protocols, resulted in a reduced total radiation dose without relevant loss of diagnostic image information. © 2006 Am Soc Emergency Radiol
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
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