• Journal of KIISE:Databases
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• v.27 no.2
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• pp.256-268
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• 2000

Multi-way spatial join is a nested expression of two or more spatial joins. It costs much to process multi-way spatial join, but there have not still reported the scheme of parallel processing of multi-way spatial join. In this paper, parallel processing of multi-way spatial join consists of parallel multi-way spatial filter and parallel spatial refinement. Parallel spatial refinement is executed by the following two steps. The first is the generation of a graph used for reducing duplication of both spatial objects and spatial operations from pairs candidate object table that are the results of multi-way spatial filter. The second is the parallel spatial refinement using that graph. Refinement using the graph is proved to be more efficient than the others. In task creation for parallel refinement, minimum duplication partitioning of the Spatial_Obicct_On_Node graph shows best performance.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.132-140
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• 2011

Ultra-High Definition Television (U-HDTV) is a promising candidate for the next generation television. Since the U-HDTV video signal requires a huge amount of data, parallel implementation of the U-HDTV compression system is highly demanding. In the conventional parallel video codec, a video is divided into sub-sequences and the sub-sequences are independently encoded. In this paper, for efficient parallel processing, we propose a pipelined encoding structure which exploits cross-correlation among the sub-sequences. The experimental results demonstrate that the proposed technique improves the coding efficiency and provides the sub-sequences of the balanced visual quality.

• KIISE Transactions on Computing Practices
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• v.21 no.7
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• pp.476-481
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• 2015

We have parallelized the cumulative sum (CUSUM) test of NIST's statistical random number test suite in a CUDA environment. Storing random walks in an array instead of in scalar variables eliminates data dependence. The change in data structure makes it possible to apply parallel scans, scatters, and reductions at each stage of the test. In addition, serial data exchanges between CPU and GPU are removed by migrating CPU's tasks to GPU. Finally we have optimized global memory accesses. The overall speedup is 23 times over the sequential version. Our results contribute to improving security of random numbers for cryptographic keys as well as reducing the time for evaluation of randomness.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.424-433
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• 2001

The cyclic debugging approach often fails for message passing parallel programs because they non-deterministic characteristics due to message race conditions. This paper identifies the MPI events that affect non-deterministic executions, and then converts the concurrent execution to the sequential one that is controlled in order to make it equivalent to a reference execution by keeping their orders of events in two executions identical. This paper also presents an efficient algorithm for the causal distributed breakpoint which is initiated by any sequential breakpoint in one process, and restores each process to the earliest state that reflects all events that happened causally before the sequential breakpoint. So a cyclic debugging approach can be used in debugging MPI parallel programs as like as in debugging sequential programming environments.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1035-1045
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• 1997

It is important to understand how we can deal with doements for the modeling of neural networks when we are unbestigating the dynamical performance and the information procoessing capabilitids.The information procewssing capabkities of model neural networks will change for different response, synaptic weights or learning rules. Using the staritical neurodyamics method, we evalute the capabikities of neural networks in order to understand the basic conept ofr parallel distributed processing. In this paper, we explain the reuslts of theoretical anaysis of the effests of the hysteretic property on the performance of wuquential associative neral networks.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.951-954
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• 1995

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09a
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• pp.40-43
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• 2008

• Journal of Welding and Joining
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• v.21 no.1
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• pp.35-41
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• 2003

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1992.06a
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• pp.525-529
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• 1992

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09b
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• pp.40-43
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• 2008