• 한국시뮬레이션학회논문지
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• 제5권2호
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• pp.41-58
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• 1996

The Discrete Event Systems Specification(DEVS) formalism specifies a discrete event system in a hierarchical, modular form. This paper presents a distributed simulation environment D-DEVSim++ for models specified by the DEVS formalism. D-DEVSim++ employs a new simulation scheme which is a hybrid algorithm of the hierarchical simulation and Time Warp mechanisms. The scheme can utilize both the hierarchical scheduling parallelism and the inherent parallelism of DEVS models. This hierarchical scheduling parallelism is investigated through analysis. Performance of the proposed methodology is evaluated through benchmark simulation on a 5-dimensional hypercube parallel machine. The performance results indicate that the methodology can achieve significant speedup. Also, it is shown that the analyzed speedup for the hierarchical scheduling time corresponds the experiment.

• 전자공학회논문지B
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• 제30B권5호
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• pp.120-128
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• 1993

In this paper, an implementation of high-speed parallel processing system for neural network design on the multicomputer network is presented. Linear speedup expandability is increased by reducing the synchronization penalty and the communication overhead. Also, we presented the parallel processing models and their performance evaluation models for each of the parallization methods of the neural network. The results of the experiments for the character recognition of the neural network bases on the proposed system show that the proposed approach has the higher linear speedup expandability than the other systems. The proposed parallel processing models and the performance evaluation models could be used effectively for the design and the performance estimation of the neural network on the multicomputer network.

• Journal of applied mathematics & informatics
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• 제5권1호
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• pp.191-200
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• 1998

There are two types of composition systems for the Korean alphabet: a combined system and a composite system. This paper decribes an efficient coding method for both of these two types. Using this coding method with the combined system yields about 10.5% code-length savings per a Korean character while it yields about 45% savings with the composite system. In other words the coding method produces a better result(i.e. 34.5% better) with the composite system than with the combined system. The simulation has been performed on a MasPar machine having 64 processors. The results show that the combined system achieved a 45.851-fold speedup while the composite system achieved a 47.274-fold speedup.

• 한국멀티미디어학회논문지
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• 제16권4호
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• pp.444-452
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• 2013

Operation time of a function or procedure is a thing that always needs to be optimized. Parallelizing the operation is the general method to reduce the operation time of the function. One of the most powerful parallelizing methods is using GPU. In image processing field, one of the most commonly used operations is morphology operation. Three types of morphology operations kernel, na$\ddot{i}$ve, global and shared, are presented in this paper. All kernels are made using CUDA and work parallel on GPU. Four morphology operations (erosion, dilation, opening, and closing) using square structuring element are tested on MRI images with different size to measure the speedup of the GPU implementation over CPU implementation. The results show that the speedup of dilation is similar for all kernels. However, on erosion, opening, and closing, shared kernel works faster than other kernels.

• The Journal of the Acoustical Society of Korea
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• 제14권2E호
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• pp.50-56
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• 1995

본 논문은 3가지 상태의 전이 그래프를 이용해서, 병렬 컴퓨터인 MasPar에 적합한 한글에 대한 효율적인 부호화를 제시하고자 한다. 본 논문에서 제시한 PHDCM(Parallel Hangul Dynamic Coding Method)의 방법을 이용한 경우에 한글 한음절당 약 3.5비트이상의 축약이 가능함을 보였다. 그리고 기존의 방법과 비교해 볼때 1비트이상의 축약이 가능함도 보였다. 또한 약 천만자의 한글을 이용해서, 병렬 컴퓨터인 MasPar에 프로세서 64개를 이용하여 실제 실행을시켰을때의 가속도 (Speedup)은 49.314임을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.482-485
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• 2000

A modified watershed transform is proposed which is context-free marker-controlled and minima imposition-free to reduce the over-segmentation and to speedup the transform. In contrast to the conventional methods in which a priori knowledge, such as flat zones, zones of homogeneous texture, and morphological distance, is required for marker extraction, context-free marker extraction is proposed by using the attention operator based on the GST (generalized symmetry transform). By using the context-free marker, the proposed watershed transform exploit marker-constrained labeling to speedup the computation and to reduce the over-segmentation by eliminating the unnecessary geodesic reconstruction such as the minima imposition and thereby eliminating the necessity of the post-processing of region merging. The simulation results show that the proposed method can extract context-free markers inside the objects from the complex background that includes multiple objects and efficiently reduces over-segmentation and computation time.

• Journal of Electrical Engineering and information Science
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• 제2권6호
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• pp.183-190
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• 1997

We present competition protocols to speed up the execution of sequential programs on a network of shared workstations in the background by exploiting their wasted computing capacity, without interfering with processes of workstation owners. In order to argue that competition protocols are preferable to migration protocols in this situation, we derive the closed form solutions for the speedup of competition protocols and migration protocols, and simulate both of protocols under comparable overhead assumptions. Based on our analytic results and simulation results, we show that competitive execution is superior to process migration, and that competitive execution can finish sequential programs significantly faster than noncompetitive execution, especially when the foreground load is sufficiently high.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.15.1-21
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• 1999

Radiosity method is a global illumination model for image synthesis. It computes all energy interactions among diffuse elements in a virtual environment. One of the major drawbacks if its time consuming computation. Existing radiosity algorithms for static scene is difficult to be applicable to dynamic environments. In this paper we proposed an hierarchical scene partition scheme to speedup the link update computations in the dynamic environments. Since the proposed spatial data structure is global, it not only can be used to speedup the culling of non-affected links after geometry change, but also can be used to accelerate the subsequent visibility computation. Several empirical tests are given to show the efficiency of our improved algorithm.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.1-8
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• 2013

In order to identify positive or negative effect of seawall on wind turbine, a wind tunnel experiment has been conducted with a 1/100 scaled-down model of Goonsan wind farm which is located in West coast along seawall. Wind speedup due to the slope of seawall contributed to about 3% increment of area-averaged wind speed on rotor-plane of a wind turbine which is anticipated to augment wind power generation. From the turbulence measurement and flow visualization, it was confirmed that there would be no negative effect due to flow separation because its influence is confined below wind turbine blades' sweeping height.

• 정보처리학회논문지A
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• 제9A권4호
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• pp.519-524
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• 2002

본 논문에서는 분산 시뮬레이션 기법 중에 하나인 MRIP(Multiple Replications In Parallel) 시나리오에서 각종 순차적인 시뮬레이션 분석 방법들의 성능을 측정할 수 있는 포함범위(Coverage)에 대한 신뢰구간(confidence intervals) 및 속도향상(Speedup)에 대해 살펴보았다. F-분포를 기반으로 한 신뢰구간에 대한 추정기(estimator)를 단일 프로세서와 다중 프로세서 상에서 참조모델(reference model)로 $M/M/1/{\infty},\;M/D/I/{\infty}과\;M/H_{2}/1/{\infty}$큐잉 시스템을 활용하여 정상상태(steady-state)에서의 평균치를 추정하는 시뮬레이션에 적용하였다. 순차적인 포함범위 분석을 위해서는 수많은 시뮬레이션 실행(Run)들이 요구되는데, MRIP 분산 시뮬레이션 시나리오에서 다중 프로세서를 이용하여 시뮬레이션을 수행하여 최종 시뮬레이션 결과를 얻는데 걸리는 신간을 감소시켰다. 또한, LNA으로 연결된 분산 컴퓨팅 시스템에 시뮬레이션을 동시에 수행시킴으로써 쉽게 필요한 수의 시뮬레이션 실행결과(Run)를 수집할 수 있다. 이는 샘플의 수가 증가됨으로써 좀더 신뢰도가 높은 최종 신뢰구간을 시뮬레이션 수행자가 얻을 수 있게 해준다.