Search

Scalability and low power consumption are major issues in designing custom hardware platforms for accelerating computation intensive electromagnetic applications. Clustered architectures decreases wire delays, power consumption and enhance scalability. We introduce a new steering algorithm that increases the performance of electromagnetic applications on such architectures, making clustering an even more attractive design alternative. The effectiveness of the new method is illustrated for two representative electromagnetic benchmarks. Index Terms--Clustered architectures, computational electromagneties, hardware acceleration.

The design and implementation of parallel finite element methods (FEMs) is a complex and error-prone task that can benefit significantly by simulating models of them first. However, such simulations are useful only if they accurately predict the performance of the parallel system being modeled. The purpose of this contribution is to present a new, practical methodology for validation of a promising modeling and simulation approach for parallel 3-D FEMs. To meet this goal, a parallel 3-D unstructured mesh refinement model is developed and implemented based on a detailed software prototype and parallel system architecture parameters in order to simulate the functionality and runtime behavior of the algorithm. Estimates for key performance measures are derived from these simulations and are validated with benchmark problem computations obtained using the actual parallel system. The results illustrate the potential benefits of the new methodology for designing high performance parallel FEM algorithms. Index Terms--Finite element methods, mesh generation, parallel processing, petri nets.

A new, efficient pipelined communication strategy that significantly reduces latency for parallel 3-D finite element mesh refinement with tetrahedra is proposed. A Petri Nets-based model is developed in order to simulate the interprocessor communication costs for both the target mesh refinement algorithm and parallel architecture. Benchmark results show that the new pipelined design yields improved communication performance and overall parallel speedup for a range of refinement problem sizes, using different numbers of processors. Index Terms--Finite element methods, mesh generation, parallel processing, petri nets.

The majority of evolutionary algorithm applications in electromagnetic design have focused on optimization of device dimensions. This approach preconceives the final device shape. To facilitate the evolution of complex and creative designs through genetic algorithms, a novel genome and genetic operators are introduced. They are then used to evolve a patch antenna for dual-frequency operation. The final design that emerges has a fitness roughly triple that of the standard approach. Index Terms--Electromagnetic optimization, genetic algorithms (GAs), patch antennas.

Exploring the vast search space of possible wire antenna designs is a task well suited for genetic algorithms. Many of the current implementations use a direct mapping between genome and antenna feature, or evolve drawing instructions. We explore the evolution of antennas using a growth process. The design of wire antennas for communication applications demonstrates the feasibility of this approach. Index Terms--Electromagnetic optimization, genetic algorithms (GAs), wire antennas.

Communication strategies in parallel finite element methods can greatly affect system performance. The communication cost for a proposed parallel 3-D mesh refinement method with tetrahedra is analyzed. A Petri Nets-based model is developed for a target mesh refinement algorithm and parallel computing system architecture, which simulates the inter-processor communication. Subsequently, estimates for performance measures are derived from discrete event simulations. The potential benefits of this approach for developing high performance parallel mesh refinement algorithms are demonstrated by optimizing the system communication costs for varying problem size and numbers of processors. Index Terms--Adaptive systems, electromagnetic analysis, finite element methods, parallel processing, software methodology.

We develop a simulation-based approach for the computational analysis and design of dynamic load balancing algorithms in parallel three-dimensional unstructured mesh refinement with tetrahedra. A Petri Nets model is implemented based on a random polling algorithm and the target multiprocessor architecture, which simulates the behavior of the parallel mesh refinement. Subsequently, estimates for performance measures are derived from discrete event simulations. The benefits of this new approach for developing high-performance parallel mesh refinement algorithms are demonstrated with results for an example geometric mesh refinement model. Index Terms--Adaptive systems, electromagnetic analysis, finite element method (FEM), parallel processing, software methodology.

Developing models from computational data is a major focus in electromagnetic design. This paper introduces ways of creating customized neural models based on a fuzzy clustering of responses. Fuzzy-clustered neural network (FCNN) models are explored, leading to increases in accuracy. The information contained within FCNN models can also be applied to space mapping electromagnetic optimization. This optimization approach strives to combine the accuracy of fine models (such as finite elements) with the low cost of coarse models. These FCNN enhancements are demonstrated through a patch antenna test case. Index Terms--Artificial neural networks (ANNs), electromagnetic modeling, electromagnetic optimization, fuzzy clustering.

An electromagnetic system can be described in a variety of ways. Coarse models provide fast evaluations but lack the required accuracy in the final stages of design. Fine models are highly accurate, but prohibitively expensive. Finding a compromise between these extremes may assist in overcoming bottlenecks in design automation and optimization. One approach is to carry out optimization in the coarse model space and use fine model simulations to fine-tune the result via space mapping. A new response surface space mapping (RSSM) strategy is presented and applied to an E-shaped patch antenna test case. The solutions that emerge are comparable to full fine model optimization at a fraction of the cost. Index Terms--Electromagnetic modeling, electromagnetic optimization, response surface (RS) models, space mapping (SM).

The potential benefits of employing optimal discretization-based (ODB) refinement criteria for vector tetrahedra to achieve load balancing in three-dimensional parallel adaptive finite-element electromagnetic analysis are considered. Specifically, the ability of this class of adaption refinement criteria to resolve effective domain decompositions based on initial discretizations with only relatively few tetrahedra is examined for generalized vector Helmholtz systems. The effectiveness of the new load balancing method is demonstrated with adaptively refined finite-element meshes for benchmark systems. Index Terms--Adaptive systems, electromagnetic analysis, finite-element methods, parallel processing.

Undergraduate electromagnetic field courses entail significant teaching and learning challenges. The use of simulation technologies in these courses can be an effective teaching strategy if designed properly. An assessment-based approach for identifying difficult concepts to incorporate into simulation-oriented learning is investigated. The potential benefits of the approach are illustrated with a case study. Index Terms--Computer-aided analysis, electrical engineering education, electromagnetic analysis, electromagnetic fields.

Finite-element (FE) accuracy can be directly affected by mesh quality. The potential benefits and related costs of a family of new mesh quality improvement systems are investigated using a suite of electromagnetic benchmarks and mesh quality measures theoretically linked to FE accuracy. Experimental findings suggest error reductions on the order of 10% for half-second runtimes. Index Terms--Adaptive systems, electromagnetic analysis, finite-element methods (FEMs), mesh improvement, mesh quality.

Finite-element solution efficiency and accuracy can be directly affected by mesh quality. When employing h-adaptive solution strategies, a mesh improvement stage is required in order to ensure high-quality tetrahedra. The potential benefits and related costs of a family of new mesh smoothing techniques are investigated with electromagnetic benchmark systems. Index Terms--Adaptive systems, electromagnetic analysis, finite-element methods, mesh quality.

The potential benefits of employing optimal discretization-based refinement criteria to achieve load balancing in parallel adaptive finite-element electromagnetic analysis are considered. Specifically, the ability of this class of adaption refinement criteria to resolve an effective domain decomposition based on initial discretizations with only relatively few degrees of freedom are examined. The new load-balancing method is evaluated with adaptively refined finite-element solutions for benchmark systems using practical adaption models. Index Terms--Adaptive systems, electromagnetic analysis, finite-element methods, parallel processing.

Accelerating numerical algorithms for solving sparse linear systems on parallel architectures has attracted the attention of many researchers due to their applicability to many engineering and scientific problems. The solution of sparse systems often dominates the overall execution time of such problems and is mainly solved by iterative methods. Preconditioners are used to accelerate the convergence rate of these solvers and reduce the total execution time. Sparse approximate inverse (SAI) preconditioners are a popular class of preconditioners designed to improve the condition number of large sparse matrices. We propose a GPU accelerated SAI preconditioning technique called GSAI, which parallelizes the computation of this preconditioner on NVIDIA graphic cards. The preconditioner is then used to enhance the convergence rate of the BiConjugate Gradient Stabilized (BiCGStab) iterative solver on the GPU. The SAI preconditioner is generated on average 28 and 23 times faster on the NVIDIA GTX480 and TESLA M2070 graphic cards, respectively, compared to ParaSails (a popular implementation of SAI preconditioners on CPU) single processor/core results. The proposed GSAI technique computes the SAI preconditioner in approximately the same time as ParaSails generates the same preconditioner on 16 AMD Opteron 252 processors. [ABSTRACT FROM AUTHOR]

The design and implementation of parallel finite element methods (FEMs) is a complex and error-prone task that can benefit significantly by simulating models of them first. However, such simulations are useful only if they accurately predict the performance of the parallel system being modeled. The purpose of this contribution is to present a new, practical methodology for validation of a promising modeling and simulation approach for parallel 3-D FEMs. To meet this goal, a parallel 3-D unstructured mesh refinement model is developed and implemented based on a detailed software prototype and parallel system architecture parameters in order to simulate the functionality and runtime behavior of the algorithm. Estimates for key performance measures are derived from these simulations and are validated with benchmark problem computations obtained using the actual parallel system. The results illustrate the potential benefits of the new methodology for designing high performance parallel FEM algorithms. [ABSTRACT FROM AUTHOR]

A new, efficient pipelined communication strategy that significantly reduces latency for parallel 3-D finite element mesh refinement with tetrahedra is proposed. A Petri Nets-based model is developed in order to simulate the interprocessor communication costs for both the target mesh refinement algorithm and parallel architecture. Benchmark results show that the new pipelined design yields improved communication performance and overall parallel speedup for a range of refinement problem sizes, using different numbers of processors. [ABSTRACT FROM AUTHOR]

Communication strategies in parallel finite element methods can greatly affect system performance. The communication cost for a proposed parallel 3-D mesh refinement method with tetrahedra is analyzed. A Petri Nets-based model is developed for a target mesh refinement algorithm and parallel computing system architecture, which simulates the inter-processor communication. Subsequently, estimates for performance measures are derived from discrete event simulations. The potential benefits of this approach for developing high performance parallel mesh refinement algorithms are demonstrated by optimizing the system communication costs for varying problem size and numbers of processors. [ABSTRACT FROM AUTHOR]

The potential benefits of employing optimal discretization-based (ODB) refinement criteria for vector tetrahedra to achieve load balancing in three-dimensional parallel adaptive finite-element electromagnetic analysis are considered. Specifically, the ability of this class of adaption refinement criteria to resolve effective domain decompositions based on initial discretizations with only relatively few tetrahedra is examined for generalized vector Helmholtz systems. The effectiveness of the new load balancing method is demonstrated with adaptively refined finite-element meshes for benchmark systems. [ABSTRACT FROM AUTHOR]

Undergraduate electromagnetic field courses entail significant teaching and learning challenges. The use of simulation technologies in these courses can be an effective teaching strategy if designed properly. An assessment-based approach for identifying difficult concepts to incorporate into simulation-oriented learning is investigated. The potential benefits of the approach are illustrated with a case study. [ABSTRACT FROM AUTHOR]