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Yayın On the equilibrium of a rigid body suspended by a set of linear springs(John Wiley & Sons, 2000-08) Tokad, YılmazIn this paper an approach is described for determining equilibrium states of a rigid body suspended elastically in space by a set of linear springs. This system is considered as a two-terminal generalized spring with terminal across (translational and rotational velocities, V-G, omega(G)) and terminal through (terminal force and moment, f(G), m(G)) variables. The algorithmic approach used for the solution of six nonlinear and coupled equilibrium equations consists of two major steps. The first step is to assign an initial orientation to the rigid body which is represented by the transformation (rotation) matrix T(theta,n) and reduce the problem to the solution of force equations only through a computer program. This yields the position vector xi of a preselected point G on the rigid body. Although the terminal force f(G) becomes zero at this position, the calculated terminal moment m(G), in general, is not equal to zero. The second step is to try to determine the correct orientation of the rigid body based on an argument that the terminal moment should vanish. The same argument is also used for the solution of force equilibrium equations. These two steps are repeated several times until both f(G) and m(G) vanish simultaneously yielding an equilibrium state (xi,T(theta, n)). Application of the approach is illustrated through various examples. It is observed that, if there are nonstable equilibrium states of the system, then sometimes all possible physical equilibrium states may not be obtained with this approach.Yayın Rate-distortion and complexity optimized motion estimation for H.264 video coding(IEEE-INST Electrical Electronics Engineers Inc, 2008-02) Ateş, Hasan Fehmi; Altunbaşak, Yücel11.264 video coding standard supports several inter-prediction coding modes that use macroblock (MB) partitions with variable block sizes. Rate-distortion (R-D) optimal selection of both the motion vectors (MVs) and the coding mode of each MB is essential for an H.264 encoder to achieve superior coding efficiency. Unfortunately, searching for optimal MVs of each possible subblock incurs a heavy computational cost. In this paper, in order to reduce the computational burden of integer-pel motion estimation (ME) without sacrificing from the coding performance, we propose a R-D and complexity joint optimization framework. Within this framework, we develop a simple method that determines for each MB which partitions are likely to be optimal. MV search is carried out for only the selected partitions, thus reducing the complexity of the ME step. The mode selection criteria is based on a measure of spatiotemporal activity within the MB. The procedure minimizes the coding loss at a given level of computational complexity either for the full video sequence or for each single frame. For the latter case, the algorithm provides a tight upper bound on the worst case complexity/execution time of the ME module. Simulation results show that the algorithm speeds up integer-pel ME by a factor of up to 40 with less than 0.2 dB loss in coding efficiency.Yayın Digital color halftoning(IEEE-INST Electrical Electronics Engineers Inc, 2005-01) Baqai, F. A.; Lee, J. H.; Agar, A. Ufuk; Allebach, Jan P.Digital color halftoning is done to create the perception of a continuous-tone color image using the limited spatiochromatic discrimination capability of the human visual system. Several techniques to perform this task are now available. These techniques are broadly classified into three groups: approaches that characterize the spectral distribution created by a certain combination of colorant dots at a given printer addressable location; dot model based approaches; and empirical tone correction based approaches.Yayın Nonlinear wave modulation in a fluid-filled linearly tapered elastic tube(Gauthier-Villars/Editions Elsevier, 2003-08) Demiray, HilmiIn the present work, treating the arteries as a thin-walled, linearly tapered, prestressed elastic tube and using the reductive perturbation method, we have studied the amplitude modulation of nonlinear waves in such a fluid-filled elastic tube. By considering the blood as an incompressible viscous fluid, the evolution equation is obtained as the dissipative nonlinear Schrodinger equation with variable coefficient. It is shown that this type of evolution equations admit a solitary wave type of solution with variable wave speeds and amplitude. It is observed that, the speed of enveloping wave increases with the scaled time parameter tau for negative tapering angle while it decreases for positive tapering. On the other hand, the speed of harmonic wave increases for positive tapering whereas it decreases for negative tapering.
