420 research outputs found

    Joint Spectrum Sensing and Resource Allocation for OFDM-based Transmission with a Cognitive Relay

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    In this paper, we investigate the joint spectrum sensing and resource allocation problem to maximize throughput capacity of an OFDM-based cognitive radio link with a cognitive relay. By applying a cognitive relay that uses decode and forward (D&F), we achieve more reliable communications, generating less interference (by needing less transmit power) and more diversity gain. In order to account for imperfections in spectrum sensing, the proposed schemes jointly modify energy detector thresholds and allocates transmit powers to all cognitive radio (CR) subcarriers, while simultaneously assigning subcarrier pairs for secondary users (SU) and the cognitive relay. This problem is cast as a constrained optimization problem with constraints on (1) interference introduced by the SU and the cognitive relay to the PUs; (2) miss-detection and false alarm probabilities and (3) subcarrier pairing for transmission on the SU transmitter and the cognitive relay and (4) minimum Quality of Service (QoS) for each CR subcarrier. We propose one optimal and two sub-optimal schemes all of which are compared to other schemes in the literature. Simulation results show that the proposed schemes achieve significantly higher throughput than other schemes in the literature for different relay situations.Comment: EAI Endorsed Transactions on Wireless Spectrum 14(1): e4 Published 13th Apr 201

    Insilico Molecular Docking - A tool to understand the action of Rasaushadhis

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    Rasashastra, a branch of Ayurveda consists of many metallo-mineral preparations which are explained as highly efficacious in smaller doses and even in shorter duration. We know the functions of Rasaushadhis (herbo-mineral preparations), but we are lacking the knowledge of their Pharmacodynamics which may benefit us in understanding the exact site where, how and which active principle work and at what rate a drug will interact with its target biomolecule. The advent of new Sciences like Bioinformatics has made drug discovery faster and economical. Bioinformatics research focuses on biology at a molecular level by identifying the effect of drugs at the level of individual genes, DNA, RNA and proteins. It utilizes existing information to model disease pathways and identifies precise targets of the drug. The unclearly answered questions can be clarified by understanding and adopting the concept of ā€˜Insilico Molecular Dockingā€™, means a computational study of binding of Ligand to specific Receptor. The action between the receptor and ligand is by selectivity and affinity; Lock and Key concept. It encompasses all theoretical methods and computational techniques to model and the behavior of molecules and by scoring function we can come to know the best suitable receptor for particular ligand. The working methodology includes preparation of Ligand, Receptor, Docking and inspection by X-Ray Crystallography, NMR techniques. The process of standardization is needed in Rasashastra but, there are some difficulties. One can overcome this by understanding the mode of action of Rasaushadhis -Rasabhasmas through molecular Docking which helps in drug discovery and development, optimisation of action and inhibition of harmful effects

    A Novel Speech Separation Based On Ica Strategical Classification

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    ABSTRACT: Monaural conversation splitting is a well-recognized process. Modern research utilize monitored classification methods to estimate the ideal binary cover up (IBM) inorder to address the issue. In a supervised learning structure, the issue of generalization to conditions different from those in coaching is most essential. This paper presents techniques that require only a little coaching corpus and can generalize to invisible circumstances. The program uses assistance vector machines to understand category hints and then runs on the rethresholding technique inorder to calculate the IBM. A submission fitting method is used to make generalizations to invisible signal-to-noise rate circumstances and voice action recognition centered variation isused to make generalizations to unseen noise circumstances. Methodical evaluation reveals that the recommended strategy generates top quality IBM estimates under invisible circumstances. Hence in this proposed method, a single channel speech enhancement algorithm is intend to offer by constructing a observational signal and noise signal for single channel speech noise reduction based on Independent component analysis (ICA),thereby noise and original speech can be separated through ICA. Hence Simulation results provides that much better peak signal to noise ratio(PSNR) and denoising effect can be procured by using this algorithm

    K-Space at TRECVID 2008

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    In this paper we describe K-Spaceā€™s participation in TRECVid 2008 in the interactive search task. For 2008 the K-Space group performed one of the largest interactive video information retrieval experiments conducted in a laboratory setting. We had three institutions participating in a multi-site multi-system experiment. In total 36 users participated, 12 each from Dublin City University (DCU, Ireland), University of Glasgow (GU, Scotland) and Centrum Wiskunde and Informatica (CWI, the Netherlands). Three user interfaces were developed, two from DCU which were also used in 2007 as well as an interface from GU. All interfaces leveraged the same search service. Using a latin squares arrangement, each user conducted 12 topics, leading in total to 6 runs per site, 18 in total. We officially submitted for evaluation 3 of these runs to NIST with an additional expert run using a 4th system. Our submitted runs performed around the median. In this paper we will present an overview of the search system utilized, the experimental setup and a preliminary analysis of our results

    On the analytical formulation of excess noise in avalanche photodiodes with dead space

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    Simple, approximate formulas are developed to calculate the mean gain and excess noise factor for avalanche photodiodes using the dead-space multiplication theory in the regime of small multiplication width and high applied electric field. The accuracy of the approximation is investigated by comparing it to the exact numerical method using recursive coupled integral equations and it is found that it works for dead spaces up to 15% of the multiplication width, which is substantial. The approximation is also tested for real materials such as GaAs, InP and Si for various multiplication widths, and the results found are accurate within āˆ¼ 15% of the actual noise, which is a significant improvement over the local-theory noise formula. The results obtained for the mean gain also confirm the recently reported relationship between experimentally determined local ionization coefficients and the enabled non-local ionization coefficients

    PBEF1/NAmPRTase/Visfatin: a potential malignant astrocytoma/glioblastoma serum marker with prognostic value

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    Malignant astrocytomas comprise anaplastic astrocytoma (AA; grade III) and Glioblastoma (GBM; grade IV). GBM is the most malignant with a median survival of 10-12 months in patients. Using cDNA microarray based expression profiling of different grades of astrocytomas, we identified several fold increased levels of PBEF1 transcripts in GBM samples. Pre-B-cell colony enhancing factor 1 gene (PBEF1) encodes Nicotinamide phosphoribosyltransferase (NAmPRTase), which catalyses the rate limiting step in the salvage pathway of NAD metabolism in mammalian cells. Further validation using real time RT-qPCR on an independent set of tumor samples (n=91) and normal brain samples (n=9), GBM specific higher expression of PBEF1 was confirmed. Immunohistochemical staining for PBEF1 on a subset of the above samples largely reinforced our finding. We carried out ELISA analysis on serum samples of astrocytoma patients to determine whether this protein levels would correlate with the presence of tumor and tumor grade. PBEF1 serum levels were substantially elevated in many of the AA and GBM patients. Statistical analysis of these data indicates that in patients with astrocytoma, serum PBEF1 levels correlate with tumor grade and is highest in GBM. Immunohistochemical analysis of an independent set of 51 retrospective GBM cases with known survival data revealed that PBEF1 expression in the tumor tissue along with its co-expression with p53 was associated with poor survival. Thus, we have identified PBEF1 as a potential malignant astrocytoma serum marker and prognostic indicator among GBMs

    Association of diabetes mellitus on cardiac remodeling, quality of life, and clinical outcomes in heart failure with reduced and preserved ejection fraction

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    Background: Diabetes mellitus frequently coexists with heart failure (HF), but few studies have compared the associations between diabetes mellitus and cardiac remodeling, quality of life, and clinical outcomes, according to HF phenotype. Methods and Results: We compared echocardiographic parameters, quality of life (assessed by the Kansas City Cardiomyopathy Questionnaire), and outcomes (1ā€year allā€cause mortality, cardiovascular mortality, and HF hospitalization) between HF patients with and without type 2 diabetes mellitus in the prospective ASIANā€HF (Asian Sudden Cardiac Death in Heart Failure) Registry, as well as communityā€based controls without HF. Adjusted Cox proportional hazards models were used to assess the association of diabetes mellitus with clinical outcomes. Among 5028 patients with HF and reduced ejection fraction (HFrEF; EF <40%) and 1139 patients with HF and preserved EF (HFpEF; EF ā‰„50%), the prevalences of type 2 diabetes mellitus were 40.2% and 45.0%, respectively (P=0.003). In both HFrEF and HFpEF cohorts, diabetes mellitus (versus no diabetes mellitus) was associated with smaller indexed left ventricular diastolic volumes and higher mitral E/eā€² ratio. There was a predominance of eccentric hypertrophy in HFrEF and concentric hypertrophy in HFpEF. Patients with diabetes mellitus had lower Kansas City Cardiomyopathy Questionnaire scores in both HFpEF and HFrEF, with more prominent differences in HFpEF (Pinteraction<0.05). In both HFpEF and HFrEF, patients with diabetes mellitus had more HF rehospitalizations (adjusted hazard ratio, 1.27; 95% CI, 1.05ā€“1.54; P=0.014) and higher 1ā€year rates of the composite of allā€cause mortality/HF hospitalization (adjusted hazard ratio, 1.22; 95% CI, 1.05ā€“1.41; P=0.011), with no differences between HF phenotypes (Pinteraction>0.05). Conclusions: In HFpEF and HFrEF, type 2 diabetes mellitus is associated with smaller left ventricular volumes, higher mitral E/eā€² ratio, poorer quality of life, and worse outcomes, with several differences noted between HF phenotypes
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