Performance of an algorithm mainly depends on both computer architecture and software. An Intel Xeon processor based HPC cluster and Intel Itanium2 based symmetric multiprocessing (SMP) architectures are used for perf...
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Performance of an algorithm mainly depends on both computer architecture and software. An Intel Xeon processor based HPC cluster and Intel Itanium2 based symmetric multiprocessing (SMP) architectures are used for performance analysis of PDE based parallel algorithm. Algorithm is parallelized using MPI and performance measurements are done using Tuning and Analysis Utilities (TAU). computational optimization reveals data independency and helps compiler to generate more efficient program for that specific processor. Removing data dependency inside loop is the key in this work. In iterative algorithms, like Gauss-Seidel method, each processor communicates with the same processors at every iteration. This feature makes persistent connection preferable. MPI has different types of communication methods for different communication characteristics. Persistent connection is one of them. Persistent connection removes connection overhead by leaving connection open for further communications. It can be preferred if data is transferred repeatedly between same nodes. In this work source code changed to help compiler to generate more efficient program for the specific processor. Also MPI persistent connection is used for communication at each iteration in Gauss-Seidel method. In some parallel algorithms, communication must be synchronized. Making communication between processors at the same time becomes a bottleneck if communication medium is shared. This fact has been studies and analyzed.
We consider reliability based aeroelastic optimization of a AGARD 445.6 composite aircraft wing with stochastic parameters. Both commercial engineering software and an in-house reliability analysis code are employed i...
We consider reliability based aeroelastic optimization of a AGARD 445.6 composite aircraft wing with stochastic parameters. Both commercial engineering software and an in-house reliability analysis code are employed in this high-fidelity computational framework. Finite volume based flow solver Fluent is used to solve 3D Euler equations, while Gambit is the fluid domain mesh generator and Catia-V5-R16 is used as a parametric 3D solid modeler. Abaqus, a structural finite element solver, is used to compute the structural response of the aeroelastic system. Mesh based parallel code coupling interface MPCCI-3.0.6 is used to exchange the pressure and displacement information between Fluent and Abaqus to perform a loosely coupled fluid-structure interaction by employing a staggered algorithm. To compute the probability of failure for the probabilistic constraints, one of the well known MPP (Most Probable Point) based reliability analysis methods, FORM (First Order Reliability Method) is implemented in Matlab. This in-house developed Matlab code is embedded in the multidisciplinary optimization workflow which is driven by Modefrontier. Modefrontier 4.1, is used for its gradient based optimization algorithm called NBI-NLPQLP which is based on sequential quadratic programming method. A pareto optimal solution for the stochastic aeroelastic optimization is obtained for a specified reliability index and results are compared with the results of deterministic aeroelastic optimization.
Active modeling is required in learning settings to cope with the dynamic evolution of the knowledge, since learners competences evolves over time as they participate in the course activities. Moreover, one of the mai...
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ISBN:
(纸本)9781424444823
Active modeling is required in learning settings to cope with the dynamic evolution of the knowledge, since learners competences evolves over time as they participate in the course activities. Moreover, one of the main issues in a competence based eLearning process is to deliver personalized instructional designs adjusted to both 1) intrinsic characteristics of users (i.e. learning styles) and 2) the desired and achieved competences in the learning process (i.e. specific and generic competences). This delivery includes the adaptation of the content and the activities in a learning scenario based on a dynamic user model that evolves according to user interactions. In this paper, an approach to support Conditional Plans Generation (IMS Learning Designs) in the context of a virtual learning environment is presented The process is supported by a pervasive usage of standards and specifications (IMS family of specifications) in conjunction with an integral user modeling.
Sensor networks are being used in several emerging applications not even imagined some years ago due to advances in sensing, computing, and communication techniques. However, these advances also pose various challenge...
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The formation and dynamics of spatially extended compositional domains in multicomponent lipid membranes both in vivo and in vitro lie at the heart of many important biological and biophysical phenomena. While the the...
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The formation and dynamics of spatially extended compositional domains in multicomponent lipid membranes both in vivo and in vitro lie at the heart of many important biological and biophysical phenomena. While the thermodynamic basis for domain formation has been explored extensively in the past, the roles of membrane and exterior fluid hydrodynamics on domain formation kinetics have received less attention. A case in point is the impact of hydrodynamics on the dynamics of compositional heterogeneities in lipid membranes in the vicinity of a critical point. In this Rapid Communication it is argued that the asymptotic dynamic behavior of a lipid membrane system in the vicinity of a critical point is strongly influenced by hydrodynamic interactions. More specifically, a mode-coupling argument is developed which predicts a scaling behavior of lipid transport coefficients near the critical point for both symmetric and asymmetric bilayers immersed in a bulk fluid.
In computing the singular values of a square matrix, transformation of the input matrix to bidiagonal form accounts for most of the computation time. In this paper, we consider speeding up this process using a combina...
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ISBN:
(纸本)9780889867840
In computing the singular values of a square matrix, transformation of the input matrix to bidiagonal form accounts for most of the computation time. In this paper, we consider speeding up this process using a combination of CPU and floating-point accelerator. As an algorithm for bidiagonalization, we can use the conventional Householder's method or Bischof's two-phase algorithm, which can use the level-3 BLAS efficiently. We can also choose to store the whole matrix in the CPU memory or in the on-board memory of the accelerator. So there are four possible strategies. We investigate the advantages and disadvantages of each strategy and construct an analytical performance model for each of them. Using the models, we predict the performance of bidiagonalzation on the CSX600 accelerator and show that it is the best to achieve high performance to use Bischof's algorithm with the matrix stored in the on-board memory. This conclusion should hold for many other accelerators with similar performance characteristics.
Sensor networks are being used in several emerging applications not even imagined some years ago due to advances in sensing, computing, and communication techniques. However, these advances also pose various challenge...
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Sensor networks are being used in several emerging applications not even imagined some years ago due to advances in sensing, computing, and communication techniques. However, these advances also pose various challenges that must be faced. One important challenge is related to the autonomous capability needed to setup and adapt the networks, which decentralizes the control of the network, saving communication and energy resources. Middleware technology helps in addressing this kind of problem, but there is still a need for additional solutions, particularly considering dynamic changes in users' requirements and operation conditions. This paper presents an agent-based framework acting as an integral part of a middleware to support autonomous setup and adaptation of sensor networks. It adds interoperability among heterogeneous nodes in the network, by means of autonomous behavior and reasoning. These features also address the needs for system setup and adaptations in the network, reducing the communication overhead and decentralizing the decision making mechanism. Additionally, preliminary results are also presented.
Background: The TGF-β/SMAD pathway is part of a broader signaling network in which crosstalk between pathways occurs. While the molecular mechanisms of TGF-β/SMAD signaling pathway have been studied in detail, the g...
We show that classical many-particle systems interacting with certain soft pair interactions in two dimensions exhibit novel low-temperature behaviors. Ground states span from disordered to crystalline. At some densit...
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We show that classical many-particle systems interacting with certain soft pair interactions in two dimensions exhibit novel low-temperature behaviors. Ground states span from disordered to crystalline. At some densities, a large fraction of normal-mode frequencies vanish. Lattice ground-state configurations have more vanishing frequencies than disordered ground states at the same density and exhibit vanishing shear moduli. For the melting transition from a crystal, the thermal expansion coefficient is negative. These unusual results are attributed to the topography of the energy landscape.
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