33,669 research outputs found

    Signal Detection for QPSK Based Cognitive Radio Systems using Support Vector Machines

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    Cognitive radio based network enables opportunistic dynamic spectrum access by sensing, adopting and utilizing the unused portion of licensed spectrum bands. Cognitive radio is intelligent enough to adapt the communication parameters of the unused licensed spectrum. Spectrum sensing is one of the most important tasks of the cognitive radio cycle. In this paper, the auto-correlation function kernel based Support Vector Machine (SVM) classifier along with Welch's Periodogram detector is successfully implemented for the detection of four QPSK (Quadrature Phase Shift Keying) based signals propagating through an AWGN (Additive White Gaussian Noise) channel. It is shown that the combination of statistical signal processing and machine learning concepts improve the spectrum sensing process and spectrum sensing is possible even at low Signal to Noise Ratio (SNR) values up to -50 dB

    Deformable subreflector computed by geometric optics

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    Using a Cassegrainian geometry, the 64-meter antenna with its distorted paraboloidal reflecting surface is forced to produce a uniform phase wavefront by a pathlength-compensating subreflector. First, the computed distortion vectors at the joints or nodes of the main reflector structure supporting the surface panels are best fitted to a paraboloid. Second, the resulting residual distortion errors are used to determine a compensating subreflector surface by ray tracing using geometric optics principles. Third, the totally corrected subreflector surface is defined by the normal directions and distances to the surface of the original symmetric hyperboloid for the purpose of evaluation. Finally, contour maps of distortions of the paraboloid reflector and the compensating subreflector are presented. A field-measured check of the subreflector in focused position as computed by the described methodology is also presented for the antenna position at horizon look with the geometry at 45 degrees elevation

    Prediction of Type II MODY3 diabetes using backpercolation.

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    This paper examined the use of the backpercolation neural network algorithm to identify mutated MODY3 gene sequence data that is responsible for type II (maturity onset) diabetes. It was then demonstrated that a supervised feed forward method gave more accurate results in predicting point mutation in genes than the neural network backpropagation method. This paper brought the technique to the attention of other researchers as to how the method can be used for this and for the prediction of other diseases. The technique had been widely used in analysing environmental data is now commonly used in Bioinformatics

    Soret and Dufour effects on unsteady mixed convection slip flow of Casson fluid over a nonlinearly stretching sheet with convective boundary condition

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    Unsteady mixed convection flow of Casson fluid towards a nonlinearly stretching sheet with the slip and convective boundary conditions is analyzed in this work. The effects of Soret Dufour, viscous dissipation and heat generation/absorption are also investigated. After using some suitable transformations, the unsteady nonlinear problem is solved by using Keller-box method. Numerical solutions for wall shear stress and high temperature transfer rate are calculated and compared with previously published work, an excellent arrangement is followed. It is noticed that fluid velocity reduces for both local unsteadiness and Casson parameters. It is likewise noticed that the influence of a Dufour number of dimensionless temperature is more prominent as compared to species concentration. Furthermore, the temperature was found to be increased in the case of nonlinear thermal radiation

    Effects of arbitrary shear stress on unsteady free convection flow of Casson fluid past a vertical plate

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    This article studies the unsteady free flow of a Casson fluid over an infinite vertical plate with constant wall temperature. The Problem is modelled by employing equations of continuity, momentum and energy. Exact solutions for the dimensionless velocity and temperature are established by the Laplace transform technique. The solutions that have been obtained, uncommon in the literature, satisfy all imposed initial and boundary conditions and can generate huge number of solutions for any motion problem with technical relevance of this type. For illustration, some special cases are considered. The velocity solutions are presented as a sum of convective and mechanical parts. Pertinent results are discussed and displayed graphically

    Prevalence and association of obesity with self-reported comorbidity: a cross-sectional study of 1321 adult participants in Lasbela, Balochistan

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    Association of fatness with chronic metabolic diseases is a well-established fact, and a high prevalence of risk factors for these disorders has increasingly been reported in the third world. In order to incorporate any preventive strategies for such risk factors into clinical practice, decision-makers require objective evidence about the associated burden of disease. A cross-sectional study of 1321 adults from one of the districts of Balochistan, among the most economically challenged areas of Pakistan, was carried out for the measures of fatness and self-reported comorbidities. Body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) were measured and demographic information and self-reported comorbidities were documented.The prevalence of obesity was 4.8% (95% CI: [3.8, 6.1]) and 21.7% (95% CI: [19.5, 24.0]), as defined by the World Health Organization (WHO) international and Asia/Asia-Pacific BMI cut-offs, respectively. The proportion exhibiting comorbidity increased with increasing levels of fatness in a dose-response relationship

    The Role of Landscape Architecture Profession in Two Different Contexts: a Comparative Review of the Practitioners in Responding to Climate Change Adaptation

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    In the context of rising concerns about global warming and sustainable development this paper examines the challenges of landscape architecture (LA) in developing and developed countries in handling climate change adaptation. The paper aims to find how the LA institutes define their professionals\u27 roles in dealing with society and environment. It seeks to focus on the professionals\u27 involvement in climate change adaptation programs in Indonesia and Australia. The paper seeks to determine how contextual factors such as institutional roles and types of prevalent governance systems shape the development of landscape architecture discipline and its professional capability with respect to other related built environment professions (architecture and planning). The websites of the ISLA (Indonesian Society of Landscape Architects) and the AILA (Australian Institutes of Landscape Architects) are examined and analysed from the perspective of professional principles of the International Federation of Landscape Architects (IFLA). The aim is to determine the LA practitioners\u27 awareness and approaches in handling climate change challenges in various roles and capabilities. It has found that the professional institute in Australia has been involved in the educational program to equip their practitioner members to have a basic knowledge and further application of climate change adaptation in their design and planning projects; whereas in Indonesia the practitioners are actively involved in community capacity building to increase people\u27s awareness and participation in mitigating the climate change at local as well as regional levels. Findings from the study seek to establish the universality of the LA profession and its relevance in both developed and developing countries

    On the role of twisted statistics in the noncommutative degenerate electron gas

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    We consider the problem of a degenerate electron gas in the background of a uniformly distributed positive charge, ensuring overall neutrality of the system, in the presence of non-commutativity. In contrast to previous calculations that did not include twisted statistics, we find corrections to the ground state energy already at first order in perturbation theory when the twisted statistics is taken into account. These corrections arise since the interaction energy is sensitive to two particle correlations, which are modified for twisted anti-commutation relations
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