• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.534-539
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• 1988

This paper presents a method to balance the links of an articulated robot for an unknown payload using an automatic balancing mechanism. The balancing masses are controlled to move in their appropriate locations so that the joint torques of the links are eliminated. After balancing the mass of the payload is obtained from the balancing conditions. Based upon a series of simulation studies some results are discussed.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06a
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• pp.349-350
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• 2008

• The Journal of Society for e-Business Studies
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• v.8 no.2
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• pp.77-98
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• 2003

A web-based information system, that is a dominant type of information systems, suffers from the "web crisis" in development and maintenance of the system. To cope with the problem, a technology of software clustering to web-based application, which is one of web engineering, is strongly needed. In this paper, we propose a Form Clustering Algorithm along with an application example, which are used for internal-system reengineering to web-based information system. A Form Clustering Algorithm focuses on Page-model which is the feature of the web among the various web-based information system's structural model. Specially, we applying distance matrix to navigation model of graph form for easily analyzing, and web log analysis for identifying core function object that have a highly loading. Also, we create web software structure that can be used to maximize reusability and assign hardware effectively through 2-phase clustering step. Form Clustering Algorithm might be used at web-based information system development and maintenance for reusable web component development and hardware assignment, respectively.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.109-116
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• 2008

Even though many studies on parallel rendering based on PC clusters have been done. most of those did not cope with non-uniform scenes, where locations of 3D models are biased. In this work. we have built a PC cluster system with POV-Ray, a free rendering software on the public domain, and developed an adaptive load balancing scheme to optimize the parallel efficiency Especially, we noticed that a frame of 3D animation are closely coherent with adjacent frames. and thus we could estimate distribution of computation amount, based on the computation time of previous frame. The experimental results with 2 real animation data show that the proposed scheme reduces by 40% of execution time compared to the simple static partitioning scheme.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.1
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• pp.19-28
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• 2000

The parallel inverter is widely utilized because of its fault-tolerance capability, high-current output at constant voltages and system modularity. The conventional paralled inverter usually employes an active and reactive power control or a frequency and voltage droop control. However, these approaches have the disadvantages that the response time of parallel inverter control is slow against load and system parameter variation to calculate active, reactive power, frequency and voltage. This paper describes novel control scheme for equalization of output power between the parallel connected inverters. The proposed scheme has a fast power balance control response, a simplicity of implementation, and inherent peak current limiting capability since it employes a instantaneous current/voltage control with output voltage and current balance and output voltage regulation. A design procedure for the proposed parallel inverter controller is presented. Futhermore, the proposed constrol scheme is verified through the simulation in various cases such as the system parameter variation, the control parameter variation and the nonlinear load condition.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.1042-1044
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• 2005

고화질 입체 영상의 효과적인 재생을 위해 PC 클러스터를 활용한 여러 형태의 병렬화 기법이 제안되었지만, 영상을 구성하는 객체의 분포가 균일하지 않은 경우 충분한 성능을 발휘하지 못하였다. 본 연구에서는 Maya 렌더러를 채택한 PC 클러스터 기반의 병렬 렌더링 시스템을 구축하고, 병렬화 성능을 높이기 위한 효과적인 부하 균형 기법을 개발하였다. 특히 애니메이션을 구성하는 연속 프레임 작업에서 프레임 간의 연관성(coherence)이 높다는 사실에 근거하여, 임의 프레임의 각 분할 영역에 소요된 계산량을 바탕으로 다음 프레임의 부하 분포를 예측하고 이에 맞게 각 프로세서의 작업 영역을 재조정하는 기법을 제안하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1259-1268
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• 2002

One of the major goals suggested in distributed system is to improve the performance of the system through the load balancing of whole system. Load balancing among systems improves the rate of processor utilization and reduces the turnaround time of system. In this paper, we design the rule of decision-making and information interchange based on knowledge based mechanism which makes optimal load balancing by sharing the future load state information inferred from past and present information of each nodes. The result of performance evaluation shows that utilization of processors is balanced, the processing time is improved and reliability and availability of systems are enhanced. The proposed mechanism in this paper can be utilized in the design of load balancing algorithm in distributed operating systems.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.439-446
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• 2001

The main stream of parallel programming today is using synchronous algorithms, where processor synchronization for correct computation and workload balance are essential. Overall performance of the whole system is dependent upon the performance of the slowest processor, if workload is not well-balanced or heterogeneous clusters are used. Asynchronous iteration is a way to mitigate such problems, but most of the works done so far are for shared memory systems. In this paper, we suggest and implement a parallel large sparse linear system solver that improves performance on distributed memory systems like clusters by reducing processor idle times as much as possible by asynchronous iterations.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.103-105
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• 2003

클러스터 자원이 그리드 환경에서 효율적으로 운영되기 위해서는 클러스터를 구성하는 노드 간의 부하균형이 필요하며 이를 위해 실행 중 프로세스 이동은 당연히 지원되어야 한다. 그러나 대부분의 그리드 지원 환경에서는 작업 시작, 실행 중 동기화 과정 등에서 프로세스들의 실행 중 이동이 고려되지 않았으며, 프로세스의 이동을 지원한다 하더라도 TCP 소켓 이전 등의 오버헤드가 따른다. 본 연구에서는 클러스터 내의 프로세스들이 실행 중에 노드 간을 이동하더라도 상호 통신이 가능하도록 별도의 통신 지원 쓰레드를 설계하고, 이를 매개로 간접 통신이 이루어지도록 개선된 방법을 제안하였다.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.241-248
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• 2002

With the structure of tilde-area computing system which Is specified by a researching team in Vrije University, Netherlands, lots of researchers and developers have been progressing the studies of global location and interconnection services of distributed objects existing in global sites. Most of them halve focused on binding services of only non-duplicated computational objects existing wide-area computing sites without any consideration of duplication problems. But all of objects existing on the earth rave the duplicated characteristics according to how to categorize their own names or properties. These objects with the same property can define as duplicated computational objects. Up to now, the existing naming or trading mechanism has not supported the binding services of duplicated objects, because of deficiency of independent location service. For this reason, we suggest a new model that can not only manages locations of duplicated objects In wide-area computing environments, but also provide minimum binding time by considering both the optimal selection of one of duplicated objects and load balance among distributed systems. Our model is functionally divided into 2 parts, one part to obtain an unique object handle of duplicated objects with same property as a naming and trading service, and the other to search one or more contact addresses by a node manager using a liven object handle, as a location service For location transparency, these services are independently executing each other. Based on our model, we described structure of wide-area integrated tree and algorithms for searching and updating contact address of distributed object on this tree. finally, we showed a federation structure that can globally bind distributed objects located on different regions from an arbitrary client object.