A statistical approach to spectrum sensing using bayes factor and p-Values

The sensing methods with multiple receive antennas  in the Cognitive Radio (CR) device, provide a promising solution for reducing the error rates in the detection of the Primary User (PU) signal. The received Signal to Noise Ratio at the CR receiver is enhanced using the diversity combiners. This paper proposes a statistical approach based on minimum Bayes factors and p-Values as diversity combiners in the spectrum sensing scenario. The effect of these statistical measures in sensing the spectrum in a CR environment is investigated. Through extensive Monte Carlo simulations it is shown that this novel statistical approach based on Bayes factors provides a promising solution to combine the test statistics from multiple receiver antennas and can be used as an alternative to the conventional hypothesis testing methods for spectrum sensing. The Bayesian results provide more accurate results when measuring the strength of the evidence against the hypothesis

NOVEL RECEIVER DIVERSITY COMBINING METHODS FOR SPECTRUM SENSING USING META-ANALYTIC APPROACH BASED ON P-VALUES

The need for efficient spectrum utilization with reduced error rates has brought a paradigm shift in wireless communication systems from a Single Input and Single Output (SISO) systems to Multiple Input Multiple Output (MIMO) systems. Conventional diversity combiners are used to boost the received Signal to Noise Ratio at the Cognitive Radio receiver. However, these methods require perfect estimation of the channel. This paper proposes a Meta-Analytic approach based on p-Values for combining the data received from a secondary user equipped with multiple antennas. The effect of the p-Value method as receiver diversity combiner is studied and is compared with the existing non-coherent combining schemes, which do not need channel state information. The weighted Z test and Fisher’s method are used to combine the p-Values derived from the Anderson Darling (AD) and Jarque Bera (JB) test statistics. A ballpark figure of the merits of these diversity combining methods are provided in this study. Through extensive Monte Carlo simulations, it is shown that the weighted Z test using the Anderson Darling test statistic provides a probability of detection very close to the existing non-coherent diversity combiners. Hence, this novel statistical approach based on p-Values provides a promising solution to combine the test statistics from multiple receiver antennas

TESTBED IMPLEMENTATION OF MULTI DIMENSIONAL SPECTRUM SENSING SCHEMES FOR COGNITIVE RADIO

Cognitive Radio (CR) is a promising technology to exploit the underutilized spectrum. Spectrum sensing is one of the most important components for the establishment of cognitive radio system. Spectrum sensing allows the secondary users (SUs) to detect the presence of the primary users (PUs). The aim of this work is to create a CR environment to study the spectrum sensing methods using Universal software radio Peripheral (USRP) boards. In this paper a novel method of estimation of spectrum opportunities in multiple dimensions especially the space and the angle dimensions are carried out on USRP boards. This paper typically provides the experimental results carried out in an indoor wireless environment. To enhance the sensing performance the space dimension is firstly studied using spatial diversity of the cooperative SUs. Secondly the receiver diversity is analyzed using multiple antennas to enhance the error performance of the wireless system. The spectrum usage is also determined in the angle dimension by investigating the direction of the dominant signals using MUSIC algorithm

TESTBED IMPLEMENTATION OF ENERGY EFFICIENT MULTI ANTENNA SYSTEM AND ITS PERFORMANCE EVALUATION

With the recent development and requirement for high-speed wireless communications, the demand of energy has increased exponentially in order to support required quality of service (QoS). Multiple Input Multiple Output (MIMO) technique gaining more popularity in current communication network, since it provides advantages in terms of higher data rates and maximum capacity with the cost of more energy consumption. In this paper, QAM modulation scheme is analyzed as the best modulation scheme for the total energy required to transmit the given number of bits is reduced. A SDR testbed has been built to implement Almouti coded MIMO system using LABVIEW and Universal Software Radio Peripheral (USRP) platform. The analysis was then extended to evaluate the energy consumption of the system where it was observed that by minimizing the transmission power the energy requirement of the system gets reduced. Then the system efficiency in terms of transmit power was evaluated using USRP. It has been observed that by adjusting carrier frequency transmit power of the system gets reduced up to 25%.Finally the performance of the system is evaluated by demonstrating the effect of transmission distance, symbol rate, spectral efficiency and circuit power on energy consumption of the system using LABVIEW math script

GEOLOCATION AWARE RESOURCE ALLOCATION IN CELLULAR BASED COGNITIVE RADIO NETWORKS WITH GREEN COMMUNICATION PERSPECTIVE

This paper puts forward a Geolocation aware spectrum and power allocation scheme for cellular-based cognitive radio network using the principle of sensing free spectrum access. The problem formulation to test the feasibility of deploying the secondary system within Terrestrial Trunked Radio (TETRA) based cellular primary system is carried out to maximize the served Secondary Users (SU) while keeping the interference to Primary Users (PU) under a predefined threshold. A novel model called Primary Mobility Contour (PMC) for the avoidance of harmful interference to PU is proposed, which will consider the velocity of PU, the time taken by the secondary base station for transmission and Geolocation information. Using this model sensing free spectrum and power allocation algorithm is developed for cellular-based cognitive radio network to maximize the served SU to enhance system throughput and achieve an enhanced energy efficiency of the system to attain green communication. Simulation results confirm that the proposed scheme maximizes the served SUs per cell, throughput and energy efficiency

Impact of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) on the quality of life of people with ME/CFS and their partners and family members: an online cross-sectional survey

Objectives The aim of this study was to assess the impact of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) on the quality of life (QoL) of people with ME/CFS and their relative or partner (family member). Design A patient-partner, multinational, subject-initiated, cross-sectional online survey. Setting International survey using ME/CFS charities, support groups and social media. Participants Participants were self-selected with recruitment via social media. Inclusion criteria were aged 18 years or over and reported diagnosis of ME/CFS by health professional. 1418 people with ME/CFS and their 1418 family members from 30 countries participated in the survey. Participants with ME/CFS had a mean age of 45.8 years (range 18–81) and were predominantly women (1214 (85.6%) of 1418). Family members had a mean age of 51.9 years (range 18–87) and were predominantly men (women: 504 (35.5%) of 1418). 991 (70%) family members were partners of the people with ME/CFS. Interventions EuroQoL-5 Dimension (EQ-5D-3L), completed by people with ME/CFS, and Family Reported Outcome Measure (FROM-16) questionnaire, completed by family members. Results The mean overall health status on a Visual Analogue Scale for people with ME/CFS was 33.8 (0=worst, 100=best). People with ME/CFS were most affected by ability to perform usual activities, pain, mobility, self-care and least impacted by anxiety. For family members, the overall mean FROM-16 score was 17.9 (0=no impact, 32=worst impact), demonstrating a major impact on QoL. Impact on QoL was significantly correlated between the person with ME/CFS and their family member (p<0.0001). Family members were most impacted emotionally by worry, frustration and sadness and personally by family activities, holidays, sex life and finances. Conclusions To the best of our knowledge, this is the largest study on the impact of the QoL of persons with ME/CFS and their family members. While open participation surveys are limited by selection bias, this research has revealed a significant worldwide burden of ME/CFS on the QoL of people with ME/CFS and their family members

Sweet sorghum bagasse – An alternative feed resource for livestock

Livestock production in the developing countries has been one of the most important economic and social activities of human culture. Among the livestock, ruminants have served and will continue to serve a valuable role in sustainable agricultural systems. They are particularly useful in converting vast renewable resources from rangeland, pasture and crop residues into food edible for humans. India has a huge ruminant population comprising of 210.2 million of cattle, 111.3 million buffaloes, 74.0 million of sheep, 154 million of goats, producing 117.0 million tons of milk and 3.4 million tons of meat (FAOSTAT 2010). Since 1970, there has been a consistent rise in the production of milk (4.7%) and meat (3.4%). Growth in livestock output, with the exception of milk, has primarily been driven by an increase in animal numbers. Yield growth in meat has been negligible, more so in the case of sheep and goats. Nutrition remains by far the most critical constraint to increased animal productivity and more efficient performance across the developing countries (ILRI 1995) with the perpetual gap between the demand and supply of digestible crude protein (DCP) and total digestible nutrients (TDN); about 35 and 37 per cent (Ramachandra et al. 2005)

Effect of microstructural evolution on magnetic properties of Ni thin films

Copyright © Indian Academy of Sciences.The magnetic properties of Ni thin films, in the range 20–500 nm, at the crystalline-nanocrystalline interface are reported. The effect of thickness, substrate and substrate temperature has been studied. For the films deposited at ambient temperatures on borosilicate glass substrates, the crystallite size, coercive field and magnetization energy density first increase and achieve a maximum at a critical value of thickness and decrease thereafter. At a thickness of 50 nm, the films deposited at ambient temperature onto borosilicate glass, MgO and silicon do not exhibit long-range order but are magnetic as is evident from the non-zero coercive field and magnetization energy. Phase contrast microscopy revealed that the grain sizes increase from a value of 30–50 nm at ambient temperature to 120–150 nm at 503 K and remain approximately constant in this range up to 593 K. The existence of grain boundary walls of width 30–50 nm is demonstrated using phase contrast images. The grain boundary area also stagnates at higher substrate temperature. There is pronounced shape anisotropy as evidenced by the increased aspect ratio of the grains as a function of substrate temperature. Nickel thin films of 50 nm show the absence of long-range crystalline order at ambient temperature growth conditions and a preferred [111] orientation at higher substrate temperatures. Thin films are found to be thermally relaxed at elevated deposition temperature and having large compressive strain at ambient temperature. This transition from nanocrystalline to crystalline order causes a peak in the coercive field in the region of transition as a function of thickness and substrate temperature. The saturation magnetization on the other hand increases with increase in substrate temperature.University Grants Commission for Centre of Advanced Studies in Physic

A systematic review of 457 randomised controlled trials using the Dermatology Life Quality Index: experience in 68 diseases and 42 countries

Background Over 29 years of clinical application, the Dermatology Life Quality Index (DLQI) has remained the most used PRO in dermatology due to its robustness, simplicity and ease of use. Objectives This systematic review aimed to generate further evidence of its utility in randomised controlled trials and is the first to cover all diseases and interventions. Methods The methodology followed PRISMA guidelines and included seven bibliographic databases, searching articles published from January 1 1994 until November 16, 2021. Articles were reviewed independently by two assessors, and an adjudicator resolved any opinion differences. Results Of 3220 screened publications, 457 articles meeting eligibility criteria for inclusion, describing research on 198,587 patients, were analysed. DLQI scores were primary endpoints in 24 (5.3%) of studies. Most studies were of psoriasis (53.2%), although 68 different diseases were studied. Most study drugs were systemic (84.3%), with biologics 55.9% of all pharmacological interventions. Topical treatments comprised 17.1% of total pharmacological interventions. Non-pharmacological interventions were 13.8% of the total interventions, mainly laser therapy and UV treatment. 63.6% of studies were multicentre, with trials conducted in at least 42 different countries, and 41.7% were conducted in multiple countries. Minimal importance difference (MID) was reported in analysis of 15.1% of studies, but only 1.3% considered full score meaning banding of DLQI. 61 (13.4%) of studies investigated statistical correlation of DLQI with clinical severity assessment or other PRO/QoL tools. 62% to 86% of studies had within group scores differences greater than the MID in “active treatment arms”. The JADAD risk of bias scale showed that bias was generally low, as 91.4% of studies had JADAD scores of ≥3; only 0.44% of studies showed high risk from randomisation, 13.8% high risk from blinding and 10.4% high risk from unknown outcome of all participants in the studies. 18.3% of studies declared that they followed an intention-to treat (ITT) protocol, and imputation for missing DLQI data was used in 34.1% of studies. Conclusions This systematic review provides a wealth of evidence for use of the DLQI in clinical trials to inform researchers’ and clinicians’ decision for its further use. Recommendations are also made for improving the reporting of data from future RCT trials using DLQI