• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.12-15
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• 2005

The subject of this research is not only to examine effects on electrical wiring that voltage drops make in low voltage load facilities found in apartments, buildings street lightings, factories, and etc, but also to discuss the voltage drops computation program on distributed random loads to optimize their safety and economy.

• 전자공학회논문지A
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• 제33A권6호
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• pp.206-219
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• 1996

This paper describes a data structure and evaluation algorithm to improve the perofmrances MOS logic-with-timing simulation in computation and accuracy. In order to efficiently simulate the logic and timing of driver-load networks, (1) a tree data structure to represent the mutual interconnection topology of switches and nodes in the driver-lod network, and (2) an algebraic modeling to efficiently deal with the new represetnation, (3) an evaluation algorithm to compute the linear resistive and capacitive behavior with the new modeling of driver-load networks are developed. The higher modeling presented here supports the structural and functional compatibility with the linear switch-level to simulate the logic-with-timing of digital MOS circuits at a mixed-level. This research attempts to integrate the new approach into the existing simulator RSIM, which yield a mixed-klevel logic-with-timing simulator MIXIM. The experimental results show that (1) MIXIM is a far superior to RSIM in computation speed and timing accuracy; and notably (2) th etiming simulation for driver-load netowrks produces the accuracy ranged within 17% with respect ot the analog simulator SPICE.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2403-2407
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• 2012

압축하중을 받는 말뚝의 하중-침하관계를 구하기 위한 하중전이법에서는 말뚝을 유한개의 요소로 분할하고 각각의 요소들에 대하여 말뚝주면변위와 주면 전이하중 그리고 말뚝선단변위와 선단저항력 사이의 적합조건으로부터 말뚝 요소의 단면력과 변위를 계산하게 된다. 통상적인 하중전이법에 의할 경우 모든 말뚝요소들에 대하여 하중-변위 사이의 적합조건을 만족하도록 반복계산을 수행해야 하므로 계산량이 과다한 단점이 있다. 본 연구에서는 압축하중을 받는 말뚝에 대한 미분방정식을 유한차분식으로 정식화하여 말뚝 바닥요소를 제외한 요소에 대해서는 반복계산 없이 직접 말뚝 단면력과 변위량을 계산할 수 있는 간편 계산법을 도입하였다. 간편 계산법에 의한 계산결과를 기존의 해석자료와 비교하여 보았는데 하중-침하관계와 말뚝 단면력 분포가 일치함을 알 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1287-1294
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• 2006

A pile is compressed with settlements when loading and bearing capacity is altered along relative displacement of pile/soil on settlement and compression. Settlements of pile displaying limit skin friction is different from displaying tip resistance. Therefore, it is an error in traditional method that bearing capacity of pile is estimated from the sum of limit skin fraction and tip resistance. Accordingly, development of design method considering behavior of load-settlement is needed. In this study, we would like to establish the base for development of design method considering bearing capacity altering along displacement on settlement and compression. For this, we established system and substance of design method. And in order to establish relationship of load-settlement of pile on the type of soil, we analyzed and arranged existing database and pile loading test. On design method, settlement is assumed gradually on each capacity level being assumed gradually. Bearing capacity developing on the pile is obtained on each settlement level. Until the obtained bearing capacity will be equal to assumed capacity, this process is continued with increasing settlement. Load-settlement curve for soil classification is sketched in the process computing settlement on assumed capacity. This design method will be materialized by computation program.

• 한국정보과학회논문지:시스템및이론
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• 제28권12호
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• pp.632-641
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• 2001

본 논문에서는 병렬컴퓨터의 하이퍼큐브, 메쉬, 트리 위상에서 부하를 재분배할 때 소요되는 계산비용을 줄이기 위한 기법을 제안하였다. 기본 개념은 두가지이다. 첫 번째는 부하를 재분배할 때 각단계마다 발생하는 idle한 링크를 겹쳐서 사용하여 전송하는 방법이며, 두 번째는 이전의 방법에 파이프라인 형태로 부하의 이동을 수행하여 링크를 최대한 사용함으로써 보다 효과적으로 계산비용을 줄이는 방법이다. 즉, idle한 링크가 가능한 발생하지 못하게 부하의 전송에 링크가 적극 참여하도록 함으로써 계산비용을 은닉하는 방법이다. 실험을 통하여 병렬컴퓨터의 위상(하이퍼큐브, 메쉬, 트리)에 따라 기존의 기법들에 두 방법을 적용한 결과, 기존의 기법보다 최소 20%에서 최대 50%의 계산비용이 감소됨을 알 수 있었다.

• 대한전기학회논문지
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• 제43권2호
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• pp.189-196
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• 1994

This paper describes a parallel computing algorithm in Gauss elimination of Jacobian matrix to large-scale power system. The structure of Jacobian matrix becomes different according to ordering method of buses. In sequential computation buses are ordered to minimize the number of fill-in in the triangulation of the Jacobian matrix. The proposed method develops the parallelism in the Gauss elimination by using ND(nested dissection) ordering. In this procedure the level structure of the power system network is transformed to be long and narrow by using end buses which results in balance of computing load among processes and maximization of parallel computation. Each processor uses the sequential computation method to preserve the sqarsity of matrix.

• 한국콘텐츠학회논문지
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• 제6권12호
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• pp.136-146
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• 2006

무선 센서 네트워크의 노드에서 측정된 데이터는 노드의 전송 거리의 제한 때문에 멀티 홉을 통해 베이스 노드에 전송된다. 또한 노드의 에너지가 한정되어 있기 때문에 무선 센서 네트워크의 수명을 연장하기 위해서는 각 노드의 에너지 소모를 가능한 균일하게 하여야 한다. Level based MultiPath Routing (LMPR)은 베이스 노드로 부터의 거리에 해당하는 노드의 레벨을 기반으로 무선 센서 네트워크를 자가 구축하고 데이터 처리 및 전송 부하를 각 센서 노드에 분산시키는 무선 센서 네트워크 라우팅 프로토콜이다. 본 논문에서는 TinyOS 기반으로 LMPR를 구현하고 실험을 통해 무선 센서 네트워크상에서 LMPR의 성능을 측정하였다. 실험 결과 LMPR이 최소 비용 방식으로 선택된 단일 경로로 데이터를 전송하는 프로토콜보다 데이터 처리 및 전송 부하를 약 4.6배 분산시켰다. LMPR 을 사용하여 데이터 처리 및 전송 부하를 각 노드에 분산시켜 TinyOS를 기반으로 구성된 무선 센서 네트워크의 수명을 연장시킬 수 있을 것으로 기대한다.

• 방송공학회논문지
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• 제10권1호
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• pp.83-102
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• 2005

The problem of video scheduling is analyzed in the framework of divisible load scheduling. A divisible load can be divided into any number of fractions (parts) and can be processed/computed independently on the processors in a distributed computing system/network, as there are no precedence relationships. In the video scheduling, a frame can be split into any number of fractions (tiles) and can be processed independently on the processors in the network, and then the results are collected to recompose the single processed frame. The divisible load arrives at one of the processors in the network (root processor) and the results of the computation are collected and stored in the same processor. In this problem communication delay plays an important role. Communication delay is the time to send/distribute the load fractions to other processors in the network. and the time to collect the results of computation from other processors by the root processors. The objective in this scheduling problem is that of obtaining the load fractions assigned to each processor in the network such that the processing time of the entire load is a minimum. We derive closed-form expression for the processing time by taking Into consideration the communication delay in the load distribution process and the communication delay In the result collection process. Using this closed-form expression, we also obtain the optimal number of processors that are required to solve this scheduling problem. This scheduling problem is formulated as a linear pro-gramming problem and its solution using neural network is also presented. Numerical examples are presented for ease of understanding.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.68-70
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• 1996

In this paper, an efficient parallel computation method for solving large sparse systems of linear algebraic equations by using Cholesky's method in the finite element method is studied. The methods of minimizing the number of fill-ins in the factorization process of factorization are investigated for minimizing the amount of memory and computation time. The parallel programming is implemented under the PVM(Parallel Virtual Machine) environment. The method of load-distribution is studied for minimizing the computation time and the communication time.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.314-317
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• 2000

Cluster system provides attractive scalability in terms of computation power and memory size. With the advances in high speed computer network technology, cluster systems are becoming increasingly competitive compared to expensive parallel machines. In parallel processing program, each task load is difficult to predict before running the program and each task is interdependent each other in many ways. Load imbalancing induces an obstacle to system performance. Most of researches in load balancing were concerned with distributed system but researches in cluster system are few. In cluster system, the dynamic load balancing algorithm which evaluates each processor's load in runtime is purpose that the load of each node are evenly distributed. But, if communication cost or node complexity becomes high, it is not effective method for all nodes to attend load balancing process. In that circumstances, it is good to reduce the number of node which attend to load balancing process. We have modeled cluster systems and proposed marginal dynamic load balancing algorithms suitable for that circumstances.