American University in Cairo

About: American University in Cairo is a education organization based out in Cairo, Egypt. It is known for research contribution in the topics: Population & Context (language use). The organization has 2472 authors who have published 5339 publications receiving 73741 citations.

Wavelet packets for GPR detection of non-metallic anti-personnel land mines based on higher-order-statistic

Abstract: An algorithm is described for the detection of non-metallic anti-personnel (AP) land mines by using ground penetrating radar (GPR). The algorithm combines two powerful tools: the wavelet packet analysis and higher-order-statistics (HOS). The use of both techniques makes detection of shallowly anti-personnel land mines objects possible which obscured by the return from air-soil interface. The experimental data sources include 1GHz pulse GPR data, and 1GHz to 4GHz stepped-frequency GPR data, from laboratory measurements.

Non-Orthogonal Multiple Access schemes in Wireless Powered Communication Networks

Abstract: We characterize time and power allocations to optimize the sum-throughput of a Wireless Powered Communication Network (WPCN) with Non-Orthogonal Multiple Access (NOMA). In our setup, an Energy Rich (ER) source broadcasts wireless energy to several devices, which use it to simultaneously transmit data to an Access Point (AP) on the uplink. Differently from most prior works, in this paper we consider a generic scenario, in which the ER and AP do not coincide, i.e., are two separate entities. We study two NOMA decoding schemes, namely Low Complexity Decoding (LCD) and Successive Interference Cancellation Decoding (SICD). For each scheme, we formulate a sum-throughput optimization problem over a finite horizon. Despite the complexity of the LCD optimization problem, due to its non-convexity, we recast it into a series of geometric programs. On the other hand, we establish the convexity of the SICD optimization problem and propose an algorithm to find its optimal solution. Our numerical results demonstrate the importance of using successive interference cancellation in WPCNs with NOMA, and show how the energy should be distributed as a function of the system parameters.

Group method analysis of unsteady free-convective laminar boundary-layer flow on a nonisothermal vertical circular cylinder

Abstract: The transformation group theoretic approach is applied to present an analysis of the problem of unsteady free convection from the outer surface of a vertical circular cylinder. The application of two-parameter group reduces the number of independent variables by two, and consequently the system of the governing partial differential equations with the boundary conditions reduces to a system of ordinary differential equations with the appropriate boundary conditions. The ordinary differential equations are solved numerically using a fourth-order Runge-Kutta scheme and the gradient method. Numerical results are obtained for the study of the boundary-layer characteristics. The general analysis developed in this study corresponds to the case of surface temperature that varies exponentially with time and uniform with respect to the axial coordinate, i.e., in the formT w =ae bt , wherea andb are constants. The effect of Prandtl number,Pr, andb on the boundary layer characteristics and the maximum value of the vertical component of the velocity are studied.