No description available.

No description available.

The Interdisciplinary Conceptual Design of Buildings Design activity during the conceptual phase of building projects is dynamic, vibrant and as a result, chaotic in appearance. This problem is compounded by the fact that iterative, or cyclic, design progression is often criticised, with the concept of 'going round in circles' being one that is discouraged. However, designbis a learning activity and, owing to the complexity of contemporary building projects,it is often only by moving ahead to improve knowledge, before taking a step back to re-address a problem with improved understanding, that the design process can progress. Today's design professionals are being urged to undertake early design activity in a more programmable, and thus manageable fashion. As such, it is becoming increasingly apparent that designers have little, if any, shared understanding of what conceptual design actually involves, let alone a deeper knowledge of the structure of iterative progression. This can, and is, causing problems for the industry, as the lack of both common understanding and synchronisation in interdisciplinary thinking is resulting in design team fragmentation and adversarial relationships. By modelling design activity it is possible to simplify, and thus ease understanding of, its complexities. The development and trialling of a generic framework of design phases and activities has allowed a simple graphical means of recording and displaying patterns of design progression to be devised. The models produced have been used to study and analyse the patterns of iterative working, the output of which has enabled a clarification of conceptual design practice to be achieved. A web-based design system has been developed from the paper-based framework. This accords well with the richly iterative and often non-linear process which design typically follows and is intended to encourage creativity without imposing a rigid procedure. The tool offers alternative routes through conceptual design, and contains 'Team Thinking Tools' to help designers widen the solution space, set priorities and evaluate options. In addition, it promotes effective teamwork practices to help teams deal with social interactions. Also, at the user's option, the system can be used to capture, store and retrieve decisions made, and the reasoning behind them. This is of key importance in improving the performance of the industry as a whole, for it is only by understanding how the final product is influenced by early design activity, that the design process can be adapted to take account of these issues on future projects.

Thesis (M.S.)--Ohio University, November, 1986. / Title from PDF t.p.

Significant effort has recently been directed towards the development of numerically efficient iterative techniques for the solution of boundary integral equation formulations of time harmonic scattering problems. The primary result of this effort has been the development of several advanced numerical techniques which enable the dense matrix-vector products associated with the iterative solution of boundary integral equations to be rapidly computed. However, an important aspect of this problem which has yet to be adequately addressed is the development of rapidly convergent iterative techniques to complement the relatively more mature numerical algorithms which expedite the matrix-vector product operation. To this end, a class of efficient iterative methods for boundary integral equation formulations of two-dimensional scattering problems is presented. This development is based on an attempt to approximately factor (i.e., renormalize) the boundary integral formulation of an arbitrary scattering problem into a product of one-way wave operators and a corresponding coupling operator which accounts for the interactions between oppositely propagating waves on the surface of the scatterer. The original boundary integral formulation of the scattering problem defines the coupling between individual equivalent sources on the surface of the scatterer. The renormalized version of this equation defines the coupling between the forward and backward propagating fields obtained by re-summing the individual equivalent sources present in the original boundary integral formulation of the scattering problem. An important feature of this class of rapidly convergent iterative techniques is that they are based on an attempt to incorporate the important physical aspects of the scattering problem into the iterative procedure. This leads to rapidly convergent iterative series for a number of two-dimensional scattering problems. The iterative series obtained using this renormalization procedure are much more rapidly convergent than the series obtained using Krylov subspace techniques. In fact, for several of the geometries considered the number of iterations required to achieve a specified residual error is independent of the size of the scatterer. This desirable property of the iterative methods presented here is not shared by other iterative schemes for wave scattering problems. Moreover, because the approach used to develop these iterative series depends only on the assumption that the total field can be approximately represented by a summation of independent and oppositely directed waves (and not on the presence of special geometries, etc.), the proposed iterative methods are very general and are thus applicable to a large number of complex scattering problems. / Ph. D.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California / This paper investigates the application of iterative equalization techniques to overcome multipath fading for shaped offset QPSK (SOQPSK) in aeronautical telemetry. Two iterative equalization techniques for turbo encoded SOQPSK are presented. The first is the optimal-MAP turbo equalizer for OQPSK. The second equalizer is the adaptive decision feedback equalizer. Simulation shows that in the presence of frequency selective multipath typically encountered in aeronautical telemetry, both of these equalizers exhibit impressive performance.

No description available.

This paper is concerned about an implementation of an accelerated domain decomposition iterative procedure. In [4], Douglas and Huang had shown the convergence for one dimensional partitioning case. This time we make an implementation to show the numerical results, and further more extend our procedure to two dimensional partitioning case. Our results show that the parameter sequence do accelerate our iterative procedure. In one dimensional partitioning case, we have the rule to choose the parameter sequence[4], but in two dimensional partitioning case, we still have no idea about the rule, but we still try to find some parameters to make our procedure more e cient. After some tests, we find that the sequence {0.4, 0.43, 0.45, 0.47, 0.5} works. Though the iteration steps in two dimensional partitioning are not decreasing, our results show the computation time is almost the same as which in the two dimensional partitioning case. It means that the parallelized program could cut down the computation cost.

In this dissertation we are concerned with the analysis of the finite element method for the time-dependent Maxwell interface problem when Nedelec and Raviart-Thomas finite elements are employed and preconditioning of the resulting linear system when implicit time schemes are used. We first investigate the finite element method proposed by Makridakis and Monk in 1995. After studying the regularity of the solution to time dependent Maxwell's problem and providing approximation estimates for the Fortin operator, we are able to give the optimal error estimate for the semi-discrete scheme for Maxwell's equations. Then we study preconditioners for linear systems arising in the finite element method for time-dependent Maxwell's equations using implicit time-stepping. Such linear systems are usually very large but sparse and can only be solved iteratively. We consider overlapping Schwarz methods and multigrid methods and extend some existing theoretical convergence results. For overlapping Schwarz methods, we provide numerical experiments to confirm the theoretical analysis.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 89-92).