2,139 research outputs found

    WCDMA Uplink Capacity of a Long Tunnel Cigar-shaped Microcells for Underground Train Service

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    In this paper, the capacity and the interference statistics of the sectors of the cigar-shaped WCDMA microcells are studied using the hybrid model of propagation. A model of nine microcells in a metro tunnel is used to analyze the uplink capacity and the interference statistics. The capacity and the interference statistics of the microcells in metro tunnels are studied in this work for different propagation parameters, antenna side lobe levels, sector ranges and bends losses

    Phenotype variability of infantile-onset multisystem neurologic, endocrine, and pancreatic disease IMNEPD

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    Infantile-onset multisystem neurologic, endocrine, and pancreatic disease (IMNEPD) has been recently linked to biallelic mutation of the peptidyl-tRNA hydrolase 2 gene PTRH2. Two index patients with IMNEPD in the original report had multiple neurological symptoms such as postnatal microcephaly, intellectual disability, developmental delay, sensorineural deafness, cerebellar atrophy, ataxia, and peripheral neuropathy. In addition, distal muscle weakness and abnormalities of thyroid, pancreas, and liver were found. Here, we report five further IMNEPD patients with a different homozygous PTRH2 mutation, broaden the phenotypic spectrum of the disease and differentiate common symptoms and interindividual variability in IMNEPD associated with a unique mutation. We thereby hope to better define IMNEPD and promote recognition and diagnosis of this novel disease entity

    THE USE OF ROUGH CLASSIFICATION AND TWO THRESHOLD TWO DIVISORS FOR DEDUPLICATION

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    The data deduplication technique efficiently reduces and removes redundant data in big data storage systems. The main issue is that the data deduplication requires expensive computational effort to remove duplicate data due to the vast size of big data. The paper attempts to reduce the time and computation required for data deduplication stages. The chunking and hashing stage often requires a lot of calculations and time. This paper initially proposes an efficient new method to exploit the parallel processing of deduplication systems with the best performance. The proposed system is designed to use multicore computing efficiently. First, The proposed method removes redundant data by making a rough classification for the input into several classes using the histogram similarity and k-mean algorithm. Next, a new method for calculating the divisor list for each class was introduced to improve the chunking method and increase the data deduplication ratio. Finally, the performance of the proposed method was evaluated using three datasets as test examples. The proposed method proves that data deduplication based on classes and a multicore processor is much faster than a single-core processor. Moreover, the experimental results showed that the proposed method significantly improved the performance of Two Threshold Two Divisors (TTTD) and Basic Sliding Window BSW algorithms

    Modeling a domain in a tutorial-like system using learning automata

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    The aim of this paper is to present a novel approach to model a knowledge domain for teaching material in a Tutorial-like system. In this approach, the Tutorial-like system is capable of presenting teaching material within a Socratic model of teaching. The corresponding questions are of a multiple choice type, in which the complexity of the material increases in difficulty. This enables the Tutorial-like system to present the teaching material in different chapters, where each chapter represents a level of difficulty that is harder than the previous one. We attempt to achieve the entire learning process using the Learning Automata (LA) paradigm. In order for the Domain model to possess an increased difficulty for the teaching Environment, we propose to correspondingly reduce the range of the penalty probabilities of all actions by incorporating a scaling factor μ. We show that such a scaling renders it more difficult for the Student to infer the correct action within the LA paradigm. To the best of our knowledge, the concept of modeling teaching material with increasing difficulty using a LA paradigm is unique. The main results we have obtained are that increasing the difficulty of the teaching material can affect the learning of Normal and Below-Normal Students by resulting in an increased learning time, but it seems to have no effect on the learning behavior of Fast Students. The proposed representation has been tested for different benchmark Environments, and the results show that the difficulty of the Environments can be increased by decreasing the range of the penalty probabilities. For example, for some Environments, decreasing the range of the penalty probabilities by 50% results in increasing the difficulty of learning for Normal Students by more than 60%

    Scope for Credit Risk Diversification

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    This paper considers a simple model of credit risk and derives the limit distribution of losses under different assumptions regarding the structure of systematic risk and the nature of exposure or firm heterogeneity. We derive fat-tailed correlated loss distributions arising from Gaussian risk factors and explore the potential for risk diversification. Where possible the results are generalised to non-Gaussian distributions. The theoretical results indicate that if the firm parameters are heterogeneous but come from a common distribution, for sufficiently large portfolios there is no scope for further risk reduction through active portfolio management. However, if the firm parameters come from different distributions, then further risk reduction is possible by changing the portfolio weights. In either case, neglecting parameter heterogeneity can lead to underestimation of expected losses. But, once expected losses are controlled for, neglecting parameter heterogeneity can lead to overestimation of risk, whether measured by unexpected loss or value-at-risk

    Giant Electroresistance in Edge Metal-Insulator-Metal Tunnel Junctions Induced by Ferroelectric Fringe Fields

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    An enormous amount of research activities has been devoted to developing new types of non-volatile memory devices as the potential replacements of current flash memory devices. Theoretical device modeling was performed to demonstrate that a huge change of tunnel resistance in an Edge Metal-Insulator-Metal (EMIM) junction of metal crossbar structure can be induced by the modulation of electric fringe field, associated with the polarization reversal of an underlying ferroelectric layer. It is demonstrated that single three-terminal EMIM/Ferroelectric structure could form an active memory cell without any additional selection devices. This new structure can open up a way of fabricating all-thin-film-based, high-density, high-speed, and low-power non-volatile memory devices that are stackable to realize 3D memory architectureope

    Natural history of irritable bowel syndrome

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73897/1/j.1365-2036.2004.01929.x.pd

    Quantile regression with group lasso for classification

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    Applications of regression models for binary response are very common and models specific to these problems are widely used. Quantile regression for binary response data has recently attracted attention and regularized quantile regression methods have been proposed for high dimensional problems. When the predictors have a natural group structure, such as in the case of categorical predictors converted into dummy variables, then a group lasso penalty is used in regularized methods. In this paper, we present a Bayesian Gibbs sampling procedure to estimate the parameters of a quantile regression model under a group lasso penalty for classification problems with a binary response. Simulated and real data show a good performance of the proposed method in comparison to mean-based approaches and to quantile-based approaches which do not exploit the group structure of the predictors

    RANKL and OPG Serum Levels in Acute Coronary Syndrome

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    Background: Numerous inflammatory mediators seem to play a pathogenic role in coronary artery disease, promoting atherogenesis and plaque destabilization, leading to thrombus formation with development of this disease. The effects of the RANKL/OPG system, like modulation of cell survival and inflammation, make it an elect mediator in the progression of atherosclerotic lesions. Objectives: To estimate the role of RANKL and OPG and their relative ratio (RANKL\OPG) in pathogenesis of acute coronary syndrome. Subjects and Methods: Sixty patients with acute coronary syndrome were enrolled in this study, those patients were divided into two groups: 31 patients were with unstable angina (UA) and 29 patients were with myocardial infarction (MI), the latter group also subdivided into [18 with ST segment elevation myocardial infarction (STEMI) and 11 with non-ST-segment elevation myocardial infarction (NSTEMI)], their ages range from 25-83 years. Twenty apparently healthy volunteers their ages and sexes were matched with the patients were also participated in the study. ELISA was carried out for estimation the serum levels of RANKL and OPG in the studied groups. Results: There was no significant difference (p>0.05) in median of serum levels of RANKL between patients and control. In addition the comparison among the three groups of patients (NSTEM1, STEM1 and UA) showed no significant differences (p>0.05) in RANKL level. Whereas the OPG level was significantly higher (p<0.001) in patients than that in healthy control, and there was significant increase in median serum level of OPG in the three patients groups as compared to control. On the other hand, there were no significant differences (p>0.05) in median serum levels of OPG among patients groups. The ratio of RANKL / OPG was significantly increase (P<0.001) in healthy control as compared to patients. The median of RANKL / OPG ratios in NSTEM1, STEM1 and UA patients groups were significantly lower (P<0.001) when compared to the ratio in healthy control. In contrast there were no significant differences in ratio among patients groups (p>0.05). Conclusion: These findings indicated that there was high significant elevation in serum level of OPG in acute coronary syndrome, so, it enforce the clinical utility of OPG in atherosclerosis and suggested that RANKL/OPG ratio could be a biomarker for acute coronary syndrome. Keywords: Acute coronary syndrome, RANKL, OPG

    Direct enzymatic esterification of cotton and Avicel with wild-type and engineered cutinases

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    In this work, the surface of cellulose, either Avicel or cotton fabric, was modified using cutinases without any previous treatment to swell or to solubilise the polymer. Aiming further improvement of cutinase ester synthase activity on cellulose, an engineered cutinase was investigated. Wild-type cutinase from Fusarium solani and its fusion with the carbohydrate-binding module N1 from Cellulomonas fimi were able to esterify the hydroxyl groups of cellulose with distinct efficiencies depending on the acid substrate/solvent system used, as shown by titration and by ATR-FTIR. The carbonyl stretching peak area increased significantly after enzymatic treatment during 72 h at 30 °C. Cutinase treatment resulted in relative increases of 31 and 9 % when octanoic acid and vegetable oil were used as substrates, respectively. Cutinase-N1 treatment resulted in relative increases of 11 and 29 % in the peak area when octanoic acid and vegetable oil were used as substrates, respectively. The production and application of cutinase fused with the domain N1 as a cellulose ester synthase, here reported for the first time, is therefore an interesting strategy to pursuit.This work was co-funded by the European Social Fund through the management authority POPH and FCT, Postdoctoral fellowship reference: SFRH/BPD/47555/2008. The authors also want to thank Doctor Raul Machado for his valuable help on FTIR spectral data treatment
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