871 research outputs found

    Scheduling Policies in Time and Frequency Domains for LTE Downlink Channel: A Performance Comparison

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    A key feature of the Long-Term Evolution (LTE) system is that the packet scheduler can make use of the channel quality information (CQI), which is periodically reported by user equipment either in an aggregate form for the whole downlink channel or distinguished for each available subchannel. This mechanism allows for wide discretion in resource allocation, thus promoting the flourishing of several scheduling algorithms, with different purposes. It is therefore of great interest to compare the performance of such algorithms under different scenarios. Here, we carry out a thorough performance analysis of different scheduling algorithms for saturated User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) traffic sources, as well as consider both the time- and frequency-domain versions of the schedulers and for both flat and frequency-selective channels. The analysis makes it possible to appreciate the difference among the scheduling algorithms and to assess the performance gain, in terms of cell capacity, users' fairness, and packet service time, obtained by exploiting the richer, but heavier, information carried by subchannel CQI. An important part of this analysis is a throughput guarantee scheduler, which we propose in this paper. The analysis reveals that the proposed scheduler provides a good tradeoff between cell capacity and fairness both for TCP and UDP traffic sources

    Emergence of hexatic and long-range herringbone order in two-dimensional smectic liquid crystals : A Monte Carlo study

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    Using a high resolution Monte Carlo simulation technique based on multi-histogram method and cluster-algorithm, we have investigated critical properties of a coupled XY model, consists of a six-fold symmetric hexatic and a three-fold symmetric herringbone field, in two dimensions. The simulation results demonstrate a series of novel continues transitions, in which both long-range hexatic and herringbone orderings are established simultaneously. It is found that the specific-heat anomaly exponents for some regions in coupling constants space are in excellent agreement with the experimentally measured exponents extracted from heat-capacity data near the smecticA-hexaticB transition of two-layer free standing film

    Mathematical Model for Image Restoration Based on Fractional Order Total Variation

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    This paper addresses mathematical model for signal restoration based on fractional order total variation (FOTV) for multiplicative noise. In alternating minimization algorithm the Newton method is coupled with time-marching scheme for the solutions of the corresponding PDEs related to the minimization of the denoising model. Results obtained from experiments show that our model can not only reduce the staircase effect of the restored images but also better improve the PSNR as compare to other existed methods

    Precarious Rock Methodology for Seismic Hazard: Physical Testing, Numerical Modeling, and Coherence Studies

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    The precarious rock methodology used for seismic hazard assessment includes location, age dating, field measurements of the quasi-static toppling acceleration of balanced rocks, and study of their dynamic response to realistic strong motion seismograms using numerical modeling. The work scope is contained in the task description issued by the DOE to the Seismology Laboratory of the University of Nevada, Reno and is itemized in section 2.3 below. In addition, measurement of the coherence of seismic energy at high frequencies, critical to the understanding of the variability of high frequency ground motions at the repository level, will be estimated based on data collected in limited scope portable instrument deployments. Existing high-frequency geophones that remain in place from earlier geophysical experiments will be used

    Obstetric outcome of phase IV of National AIDS Control Programme at a tertiary care centre

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    Background: This study was conducted to observe maternal and fetal outcome of sero-positive women delivering at our centre by using the newly introduced National AIDS Control Programme (NACP) phase IV of HARRT (highly active antiretroviral therapy) recommended by National AIDS Control Organisation (GOI) started from 1st January 2014.Methods: Study included all seropositive pregnant women diagnosed during pregnancy and in emergency at labour room of Government Medical College, Aurangabad, Maharashtra, India in 2 years period. The women and their newborns were managed as per recommendations of phase IV of National AIDS Control Programme of Government of India.Results: There was reduction in associated maternal infections, high CD4 counts, increase in vaginal deliveries, promotion of exclusive breast feeding and limitation of vertical transmission of HIV. The adverse impact of HIV on mother and newborn still continues.Conclusions: Phase IV of NACP appears to be promising in the initial phases of its implementation

    Fungal infections in patients with chronic liver disease: mortality and associated risk factors

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    Background: Patients with chronic liver disease are immunocompromised and prone to different opportunistic infections. Fungal infections in patients admitted with liver cirrhosis are not rare and they may increase mortality and morbidity of these patients. Aims of the study is to determine the mortality and its risk factors associated with fungal infections in patients with chronic liver disease.Methods: In this retrospective study, patients admitted with chronic liver disease during the last four years on this hospital were studied for diagnosed fungal infections. A matched control group of cirrhosis patients with a ratio of 1:2 admitted without fungal infections was also studied and mortality was compared between the two groups.Results: Seventy admitted patients of liver cirrhosis with microbial and histopathological evidence of fungal infection were found while 140 patients of the control group had no evidence of fungal infection. Hepatitis C virus infection was the major cause of cirrhosis (65%) and most of the patients were in child class C(63%). Urinary tract infection, esophageal candidiasis, and mucormycosis were major fungal infections. Mortality was much higher in the fungal infections group (34.3%) as compared to the non-infectious group (16%). On multivariate analysis, high WBCs count, hypo-albuminemia and high creatinine levels were the worst factors affecting mortality.Conclusions: Fungal infections are a significant cause of morbidity and mortality in patients with decompensated cirrhosis. Advanced cirrhosis, renal insufficiency, and leucocytosis are independent predictors of fatal outcome in these patients

    Structural Changes in Thin Keratoconic Corneas Following Crosslinking with Hypotonic Riboflavin: Findings on In Vivo Confocal Microscopy

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    Purpose: To report structural changes observable in in vivo confocal microscopy (IVCM) in keratoconic corneas <400 μm treated with hypotonic riboflavin and collagen crosslinking (CXL). Method: Ten eyes of ten patients with progressive keratoconus and corneal thickness between 350 and 399 μm underwent CXL with hypotonic riboflavin. IVCM was performed preoperatively and at one month, three months, and six months after the procedure. Results: IVCM analysis one month postoperatively showed complete absence of the subepithelial nerve plexus with gradual regeneration over six months in 8 of the 10 eyes, and poor regeneration in the remaining 2 eyes. The anterior stroma showed extracellular lacunae and hyper-reflective cytoplasm in a honeycomb appearance signifying edema at one month which gradually decreased over six months post CXL. Stromal keratocyte apoptosis was evident in the anterior stroma in all cases and extended to the posterior stroma in four eyes with gradual regeneration evident at three and six months. The specular endothelial count decreased by 8% (P = 0.005) post-CXL, but no corneas developed clinical signs of endothelial trauma. Conclusion: IVCM analysis of thin corneas after hypotonic CXL showed posterior corneal structural changes. Posterior stromal changes were accompanied by a decrease in the endothelial cell count. This case series was a preliminary feasibility study that might necessitate conducting a well-designed controlled study

    Efficacy and safety of sofosbuvir based antiviral therapy for chronic hepatitis C infection in patients with advanced chronic kidney disease

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    Background: Screening studies for hepatitis C have proved that it is more prevalent in patients with renal diseases. Chronic hepatitis C infection in patients with kidney disease not only accelerates renal deterioration but also adversely effects morbidity and mortality. Availability of direct acting antiviral drugs has revolutionized treatment of hepatitis C even in difficult patients. In advanced kidney diseases, selection of treatment is difficult. Aim of this study was to evaluate the efficacy and safety of Sofosbuvir based DAAs in patients with advanced CKD.Methods: In this Quasi experimental study, CHC patients with or without cirrhosis having advance CKD (eGFR <30 ml/min per 1.73 m2) and/or on dialysis were enrolled. End points of the study were documentation of SVR 12 or discontinuation of therapy. Different regimens of oral DAAs with or without Ribavirin were used.Results: 86 patients with a median age of 53 years were enrolled. 37 patients were on maintenance dialysis and 49 were not on dialysis with eGFR <30 ml/min per 1.73 m2. Virological response was 92.68% at the end of treatment and SVR was achieved by 90.2% twelve weeks after therapy. Insomnia 14%, headache 11% and anemia 7% were main dverse effects. Mean eGFR and creatinine before and after treatment remained the same. Only 2 patients relapsed, both were on dialysis thrice weekly.Conclusions: All Sofosbuvir based regimens used for the treatment of CHC in patients with end stage renal disease are effective and well tolerated. Close follow up is advised to monitor side effects
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