• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9B
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• pp.1652-1660
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• 1999

One of the most important goals in VOD servers is to provide services to more clients with services which clients request. In order to provide service efficiently and rapidly, though considering a few of policies, efficient placement of data when they are stored is direct cause to improve efficiency of retrievals. In this paper, we propose a efficient placement policy, encoded video data being stored in clustered VOD servers. In the proposed placement policy, partitioning a large disk array into smaller disk groups which consists of a few of disks with similar performances, specially disk I/O bandwidth. In last chapter, we compare proposed placement policy with conventional policies, and show the results of improved performances with proposed policy.

• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.63-63
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• 2006

• Journal of Internet Computing and Services
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• v.19 no.3
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• pp.25-33
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• 2018

This paper proposes a cloud workflow model theoretically supported by the information control net modeling methodology as a cloud workflow modeling methodology that is mandatory in implementing realtime enterprise workflow management systems running with cloud computing environments. The eventual goal of the cloud workflow model proposed in this paper is to support those cloud workflow architectures reflecting the types of cloud deployment models such as private, community, public, and hybrid cloud deployment models. Moreover, the proposed model is a mathematical graph model that is extended from the information control net modeling methodology used in conventional enterprise workflow modeling, and it aims to theoretically couple this methodology with the cloud deployment models. Finally, this paper tries to verify the feasibility of the proposed model by building a possible cloud workflow architecture and its cloud workflow services on a realtime enterpeise cloud workflow management system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.670-673
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• 2010

무기저 손상 진단 기법은 능동센서를 이용하여 과거의 기저자료와 현재 상태에서 취득한 유도파의 정보를 비교하지 않고, 구조물의 현재 상태에서 취득한 신호만을 분석함으로써 구조물의 상태를 진단하는 기법이다. 온도 변화 및 하중 변화 등의 외부 환경의 변화에 민감한 유도파의 특성으로 인하여 기저자료를 이용하는 과거의 방법론은 현실적용성이 떨어질 우려가 있다. 본 무기저 손상 진단 기법은 외부 환경적 영향을 최소화함으로써 구조물의 상태를 효율적으로 진단할 수 있다. 최초, 본 연구진에서 제안하였던 무기저 기법은 두 쌍의 능동센서를 구조물에 양면 대칭으로 배치시켜 능동센서의 극성을 이용한 방법이었다. 하지만 실제 구조물의 양면에 완벽한 대칭성을 유지하며 능동센서를 배치시키는 것은 사실상 불가능하다. 이와 같은 한계점을 극복하기 위해 신개념의 듀얼 능동센서를 활용한 무기저 손상 진단 기법이 제안되었고, 수치해석 및 연구실 환경에서 제한적으로 그 실용성이 검증되었다. 본 논문에서는 무기저 손상 진단 기법의 실 구조물에의 적용성을 폐교량을 대상으로 검토하였다. 특히, 보강재를 포함하는 영역에서 본 기법을 적용함으로써 실제 구조물에 적용 가능성을 검증하였다.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.715-728
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• 2009

The Enterprise Service Bus based on Java Business Integration is an web service standard and one of the methods for implementing distribution channels of Service Oriented Architecture. Consisting of open source group, extensive venders and users, the ESB based JBI has the problems of ineffectiveness as well as advantages of extensibility of service plug-in. That is, in case users need to use Service plug-in, manual connection of packaging process and sequential distribution method is required. This study, therefore, proposes as a way of trouble-shooting the user-oriented component deployment tool which can manage entire process for deploying The ESB middleware platform to Service unit. At the same time, this study elicited the requirements based on issues of JBI-based ESB and has developed the modeling property, packaging, distribution and evaluation thru Schema analysis of JBI-compatible component. Using the deployment tool this study proposed, users will be able to perform and manage the whole deploying process without additional manual work for connecting component. Not only it is expected that interface based on Graphic User Interface provide usability and convenience but they can also minimize the errors rate through component and route validity verification function provided in deployment tool.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.134-137
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• 2010

본 논문에서는 대방미사일(ARM: Anti Radiation Missile)로부터 레이다를 보호하기 위하여 디코이 안테나를 이용한 전파회피기술을 효과적으로 모의하기위한 시뮬레이터를 제안하자 한다. 제안된 시뮬레이터는 디코이(Decoy) 안테나의 효과적인 배치와 ARM 수신기에 수신되는 전파의 특성 분석이 가능하도록 설계되었다. 디코이 안테나의 배치 효과를 검증하기위해서 ARM 수신기에 도달하는 디코이 안테나 신호의 위상과 진폭을 분석 결과를 제시하였다. 또한 다수 디코이 안테나를 사용하는 경우 ARM의 공격효과를 다양하게 분석하였으며 ARM 방어를 위한 효과적인 디코이 배치에 유용하게 활용 될 것이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.29-31
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• 2012

사고선박을 예선(또는 예인선)을 이용하여 안전한 곳으로 이동시키기 위해서는 예인소요마력을 계산하여 예선의 척수를 결정해야 한다. 예선의 신속한 투입은 잠재적인 환경오염 및 사고선박의 2차적인 피해로의 확산을 예방할 수 있다. 하지만, 국내에는 아직까지 사고선박의 형태, 크기, 외력조건에 따라 지원되어야 할 예선의 척수 산정 및 최적의 배치방법에 대한 정량적이고 체계적인 결정 시스템이 없는 실정이다. 따라서 본 연구에서는 실선을 활용한 소요마력 측정을 위한 실험방법의 제시와 상황에 따른 예선의 다양한 배치에 따른 장력 측정 방법을 제시하고, 이러한 실험을 통하여 얻은 결과를 이론계산 결과와 비교 분석함으로써 추후 구축하게 될 사고선박 예인지원시스템 프로그램 개발을 위한 이론식을 정립하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.4726-4731
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• 2011

This paper proposed the algorithm to select optimal grinding condition for plunge grinding in the batch production unit. In order to apply to the proposed algorithm, the state variable for plunge grinding process was defined and the optimal grinding condition for each cycle in batch production was decided by genetic algorithm. Based on the optimized grinding condition in each cycle, the optimal grinding condition for whole batch production was selected by dynamic programming. The proposed algorithm was evaluated by computer simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.185-190
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• 2016

Damages of the main engine aftmost bearing and the after stern tube bearing tend to increase due to misalignment. And as the shafting system becomes stiffer due to the large engine power, whereas the hull structure becomes more flexible due to optimization by using high tensile thin steel plates. And this is the reason that more sophisticated shaft alignments are required. In this study, the optimum shafting alignment calculation was carried out, considering the thermal expansion effect, exploiting the sensitivity index, which indicates the reasonable position of forward intermediate shaft bearing for shaft alignment. and as the main subject in this study, the elastic deformation on intermediate shaft and main engine bearings occurred by vertical load of shaft mass were examined thoroughly and analyzed allowable load of bearings, reaction influence numbers of all bearings. As the result, a reliable optimum shafting alignment was derived theoretically. To verify these results, they were referred to the engine maker's technical information of main engine installation and being used shafting alignment programs of both Korean Register of Shipping and Det Norske Veritas, their reliability were reviewed.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.2971-2984
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• 1997

In this paper, we propose an efficient video block Placement scheme that utilize the current disk product that has MZR disk characteristic and users' skewed access pattern on VOD. Also, we evaluate its performance through simulation and modeling of VOD server. The basic placement rule is to place on MZR disks by LP, SHP methods according to the Zipf distribution of popularity. To verify the proposed scheme, we examined its performance on workstation with 2 MZR disks under varied skewed factors. The proposed placement scheme showed better response time than the random method. To extend proposed placement scheme to disk group, we analyzed the theoretical maximum numbers of concurrent users and the required buffer size per user. For performance parameters for the proposed scheme, we considered the disk head scheduling methods, the placement methods and the striping unit. The result of experiments showed that the proposed scheme was effective.