Scattering of seismic waves by three-dimensional large-scale hill topography simulated by a fast parallel IBEM

To solve seismic wave scattering by a large-scale three-dimensional(3-D) hill topography, a fast parallel indirect boundary element method(IBEM) is developed by proposing a new construction method for the wave field, modifying the generalized minimum residual(GMRES) algorithm and constructing an Open MP plus MPI parallel model. The validations of accuracy and efficiency show that this method can solve 3-D seismic response of a large-scale hill topography for broadband waves, and overcome the weakness of large storage and low efficiency of the traditional IBEM. Based on this new algorithm architecture, taking the broadband scattering of plane SV waves by a large-scale Gaussian-shaped hill of thousands-meters height as an example, the influence of several important parameters is investigated, including the incident frequency, the incident angle and the height-width and length-width ratio of the hill. The numerical results illustrate that the amplification effect on the ground motion by a near-hemispherical hill is more significant than the narrow hill. For low-frequency waves, the scattering effect of the higher hill is more pronounced, and there is only a single peak near the top of the hill. However, for high-frequency waves, rapid spatial variation of displacement amplitude appears on the hill surface.

Full electromagnetic transient simulation for large power systems

For building Global Energy Interconnection(GEI), it is necessary to implement new breakthroughs on largepower system simulation. Key routes for implementing full electromagnetic transient simulation of large-power systems are described in this paper, and a top framework is designed. A combination of the new large time step algorithm and the traditional small-time step algorithm is proposed where both parts A and B are calculated independently. The method for integrating the Norton equivalence of the power electronic system to the entire power grid is proposed. A two-level gird division structure is proposed, which executes a multi-rate parallel calculation among subsystems and element parallel calculation in each subsystem. The initialization method of combining load flow derivation and automatic trial-and-error launching is introduced. The feasibility of the method is demonstrated through a practical power grid example, which lays a foundation for further research.

Online Plasma Shape Reconstruction for EAST Tokamak

An online plasma shape reconstruction, based on the offiine version of the EFIT code and MPI library, can be carried out between two adjacent shots in EAST. It combines online data acquisition, parallel calculation, and data storage together. The program on the master node of the cluster detects the termination of the discharge promptly, reads diagnostic data from the EAST mdsplus server on the completion of data storing, and writes the results onto the EFIT mdsplus server after the calculation is finished. These processes run automatically on a nine-nodes IBM blade center. The total time elapsed is about 1 second to several minutes, depending on the duration of the shot. With the results stored in the mdsplus server, it is convenient for operators and physicists to analyze the behavior of plasma using visualization tools.

Design of a Hardware-Implemented Phase Calculating System for Feedback Control in the LHCD Experiments on EAST

A fully hardware-implemented phase calculating system for the feedback control in the lower-hybrid current drive （LHCD） experiments is presented in this paper. By taking advantages of field programmable gate array （FPGA） chips with embedded digital signal processing （DSP） cores and the Matlab-aided design method, the phase calculating algorithm with a square root operation and parallel process are efficiently implemented in a single FPGA chip to complete the calculation of phase differences fast and accurately in the lower-hybrid wave （LHW） system on EAST.

THE PARALLEL CALCULATION METHOD OF INCOMPRESSIBLE VISCOUS FLOW IN CYLINDRICAL PASSAGE

In the paper, the parallel calculation method is used to solve the problem of incompressible viscous laminar flow in a cylindrical passage. The whole calculated area is divided into sub-ranges by the strip range split method with overlapping, and the momentum and pressure correction equations are solved respectively. For the pressure correction equation, the block correction method is used to quicken the convergence speed of linear algebraic equations.The calculation is carried out on micro-computer outfitting TRANSPUTER boards. The results show good parallel quickened ratio and parallel efficiency.

Global Dynamic Load Balancing Based on Data-omitting （GDLBD）

E-mail, WWW, FTP, BT and QQlive, etc. axe used more and more universal because the advantage of Internet, but the data-omitting phenomenon is a headache problem. In this paper, we consider the problem of allocating a large number of independent, unequal-sized loads exchanged between servers and clients or between themselves when there are data-omitting, and we describe the dynamic load balancing problems by intro- ducing some parameters αij, we use an undirected graph to model the platform, where servers （CPU time, disk memory） can have different speeds of computation and communication. Because the number of loads is large, we focus on the question of determining the optimal dynamic load balancing scheduling strategy （splittable strategy） for each processor （the fraction of time spent computing and the fraction of time spent communication with each neighbor）. We show that finding the optimal dynamic load balancing state can be solved using a linear programming approach by adding more constrains and, thus, in polynomial time. And make the execute time minimization.