Wireless Information and Power Transfer in Full-Duplex Systems with Massive Antenna Arrays

We consider a multiuser wireless system with a full-duplex hybrid access point (HAP) that transmits to a set of users in the downlink channel, while receiving data from a set of energy-constrained sensors in the uplink channel. We assume that the HAP is equipped with a massive antenna array, while all users and sensor nodes have a single antenna. We adopt a time-switching protocol where in the first phase, sensors are powered through wireless energy transfer from HAP and HAP estimates the downlink channel of the users. In the second phase, sensors use the harvested energy to transmit to the HAP. The downlink-uplink sum-rate region is obtained by solving downlink sum-rate maximization problem under a constraint on uplink sum-rate. Moreover, assuming perfect and imperfect channel state information, we derive expressions for the achievable uplink and downlink rates in the large-antenna limit and approximate results that hold for any finite number of antennas. Based on these analytical results, we obtain the power-scaling law and analyze the effect of the number of antennas on the cancellation of intra-user interference and the self-interference.Comment: Accepted for the IEEE International Conference on Communications (ICC 2017

Association between generation gap in interest, familiarity and application of information and communication technology

Given the introduction of information and communication technology and its rapid progress in every society, its use and application is different between various social institutions in that it demonstrates the difference between previous and present generation. Hence, the research was conducted in the school year 2012-2013 with the aim of applying information technology among female high school students and their mothers in Gorgan Province. The research method is a descriptive-analytical method; using a cluster sampling, of 34 female schools 8 schools were randomly chosen and 260 students were included in the study out of 1625 students. Using collected questionnaires and information obtained from independent t-test the results indicated that there was a significant difference between the mean of familiarity, interest and mothers' and their children's use of information technology. © Medwell Journals, 2016

Solvent free one pot synthesis of novel naphtho[1,8-gh] quinazoline-7,10-dione derivatives with CuCl2

The Biginelli-type reaction of phenalen-1,3-dione with urea, and benzaldehyde derivatives in the presence of CuCl2 as a catalyst for the synthesis of naphtho[1,8-gh]quinazoline-7,10-diones in solvent free condition are reviewed. Excellent yields of the products, short reaction times and simple work-up are attractive features of this suitable protocol.               KEY WORDS: Synthesis, Naphtho[1,8-gh]quinazoline-7,10-diones, One pot, Solvent free Bull. Chem. Soc. Ethiop. 2018, 32(1), 149-156DOI: https://dx.doi.org/10.4314/bcse.v32i1.1

Correlation between anthropometric indexes and risk factors of cardiovascular diseases among the elderly population in Amirkola

Background: The ageing of population is an increasing phenomenon worldwide. Cardiovascular diseases are one of the most important chronic disease in ageing. The aim of this study was to investigate the correlation between the anthropometric indexes and risk factors of cardiovascular diseases among the elderly population in Amirkola (Mazandaran, Iran). Materials and Methods: This descriptive-analytical cross-sectional study was a part of the Amirkola Health and Ageing Cohort Project (AHAP). Demographic information was collected using a standard questionnaire. Fasting blood samples were collected from all participants to measure the serum level of lipids. Measurement of systolic and diastolic blood pressure and anthropometric indexes e.g. body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) and waist to height ratio (WHR) were done for all participants. Results: One thousand five hundred and six elderly people of Amirkola (age> 60 years) were participated in this study. There was a positive and significant correlation between the BMI and systolic and diastolic blood pressures, total cholesterol (TC), high density lipoprotein-cholesterol (HDL-C) and triglyceride. The WC had a positive and significant correlation with systolic and diastolic blood pressures, HDL-C and triglyceride. The correlation between WHR and systolic and diastolic blood pressures, HDL-C and triglyceride was positive and significant; however the correlation between the anthropometric indexes and TC and low density lipoprotein-cholesterol (LDL-C) was negative and significant. The WHR had a significant positive correlation with all studied risk factors. Conclusion: According to the findings of present study, WHR index had stronger correlation with risk factors for cardiovascular disease in the elderly

Throughput Analysis and Optimization of Wireless-Powered Multiple Antenna Full-Duplex Relay Systems

We consider a full-duplex (FD) decode-and-forward system in which the time-switching protocol is employed by the multi-antenna relay to receive energy from the source and transmit information to the destination. The instantaneous throughput is maximized by optimizing receive and transmit beamformers at the relay and the time-split parameter. We study both optimum and suboptimum schemes. The reformulated problem in the optimum scheme achieves closed-form solutions in terms of transmit beamformer for some scenarios. In other scenarios, the optimization problem is formulated as a semi-definite relaxation problem and a rank-one optimum solution is always guaranteed. In the suboptimum schemes, the beamformers are obtained using maximum ratio combining, zero-forcing, and maximum ratio transmission. When beamformers have closed-form solutions, the achievable instantaneous and delay-constrained throughput are analytically characterized. Our results reveal that, beamforming increases both the energy harvesting and loop interference suppression capabilities at the FD relay. Moreover, simulation results demonstrate that the choice of the linear processing scheme as well as the time-split plays a critical role in determining the FD gains.Comment: Accepted for publication in IEEE Transactions on Communication

Modelling the dynamics of turbulent floods

Consider the dynamics of turbulent flow in rivers, estuaries and floods. Based on the widely used k-epsilon model for turbulence, we use the techniques of centre manifold theory to derive dynamical models for the evolution of the water depth and of vertically averaged flow velocity and turbulent parameters. This new model for the shallow water dynamics of turbulent flow: resolves the vertical structure of the flow and the turbulence; includes interaction between turbulence and long waves; and gives a rational alternative to classical models for turbulent environmental flows