Mohamed Shalaby

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We compare several methods for approximate implicitization by piece-wise polynomials which have been developed by the authors, and a linear-algebra-based numerical method for implicitization which is provided as a part of MAPLE. We investigate both quantitative criteria (such as computing time, memory use, and the error of the approximation) and qualitative(More)
We present techniques for creating an approximate implicit representation of space curves and of surfaces of revolution. In both cases, the proposed techniques reduce the problem to that of implicitization of planar curves. For space curves, which are described as the intersection of two implicitly defined surfaces, we show how to generate an approximately(More)
We report on approximate techniques for conversion between the implicit and the parametric representation of curves and surfaces, i.e., implicitization and parameterization. It is shown that these techniques are able to handle general free-form surfaces, and they can therefore be used to exploit the duality of implicit and parametric representations. In(More)
Cognitive radio is an emerging technology, which aims to upgrade the spectrum utilization by allowing the secondary users to operate at the spectrum bands vacated by the primary users. A cognitive radio system model was simulated and the performance of the energy detector was evaluated by using different wireless channel models. These models include(More)
The deployment of femtocells in a LTE advanced system can extend the system coverage to include indoors. Unfortunately, an electromagnetic interference may occur among the femto users and the macro users in the case of co-channel deployment. A cognitive radio can be used to mitigate the interference among the femtocells and the macrocells. It is applied by(More)