• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.240-243
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• 2009

본 논문에서는 수중에서 이동하는 무인잠수정 및 수중이동체의 위치를 측정하는 방법 중의 하나인 동적 단기선 방식(SBL)에 의한 무인잠수정의 위치측정에 대한 방법을 하이드로폰과 DAQ(Data Aquisition) 시스템을 이용하여 수조에서 테스트를 수행하였고, 실 해역에서의 실험을 실시하였다. 실험을 위해서 4개의 센서가 수조의 벽면에 고정이 되어 있으며, 이동체와 고정된 4개의 센서가 신호를 송수신함으로써 상호간의 위치추적이 가능하게 하는 시뮬레이션을 실시하였으며, 제안하는 SBL시스템과 장기선 방식(Long baseline)을 비교하기위한 시뮬레이션을 실시하여 두 시스템을 비교하였다. 측정된 신호는 DAQ 시스템을 이용하여 데이터를 취득하였고, Labview 프로그램을 이용하여 실시간으로 무인잠수정의 위치를 추정하였다. 위치추정에 사용된 알고리즘은 삼각측량법에 의한 방법을 사용하였으며, X, Y방향에 대해서는 비교적 오차가 적은 추정 결과를 나타내었으나 Z방향에 대하여서는 큰 오차를 보여 데이터로 사용할 수 가 없었다. 이는 수중이동체의 수심측정 센서를 이용하여 보완할 수 있을 것으로 본다. 향후 연구로는 위치추정 알고리즘을 보완하여 실제 선박 선저부에 센서가 부착되었을 경우에 대한 적용연구를 진행할 예정이며, 위치추정 알고리즘을 발전시켜 3차원에서의 정확한 위치 추적을 가능하게 할 예정이다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.1
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• pp.35-42
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• 1997

Subsea cable systems have a large information transmission capacity and play an important role in domestic and global information networks. However since the cables are under harsh marine environment, they are exposed to various hazards with high potential risks of damage resulting in serious economic loss. In this research a computer simulation program based on the finite difference algorithm was developed. The program is able to simulate two dimensional dynamic behaviour of a submarine cable during its laying. In order to verify the numerical results, they are compared to analytical results, showing a good agreement between the two results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.466-474
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• 2003

In this paper, we develope the simulation model for Ethernet passive optical networks (Ethernet-PON) by using OPNET. Ethernet-PON is an emerging access network technology that provides a low-cost method of deploying optical access lines. The simulator uses a Request/Grant TDMA MAC protocol based on IEEE 802.3ah EFM. It also executes registration, ranging and dynamic bandwidth allocation algorithm by exchanging control packets between OLT and ONUs. We have evaluated for success ratio of initial registration process and delay of late registration process. We also have simulated for dynamic TDMA protocol and static TDMA protocol in terms of channel utilization and queueing delay. We expect that this simulator can help to determine various parameters which are considered for designing Ethernet-PON system.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.328-333
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• 2007

The purpose of this study is modelling of system air-conditioner for TRNSYS. System air-conditioner is operated by a variable capacity compressor and accommodated by multiple evaporators. By reason of these feature, realizing performance of system air-conditioner for TRNSYS was incomplete. In this study performance data of system air-conditioner and control logics are used to make system air-conditioner module for TRNSYS. Performance data contains total capacity, power input and capacity index of system air-conditioner. The simulation was carried out in a mode of temperature level control using TRNSYS 16. The simulation shows that the system air-conditioner model operate variable capacity and can compute capacity index and power input of system.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.221-226
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• 2002

Cycling Packet Dropping mechanism we proposed in this paper adaptively drops packets, as predicting traffic pattern between each cycle. Therfore the proposed mechanism makes up for the drawback of RIO mechanism and minimizes errors being capable of predicting in Dynamic and Strict Packet Dropping mechanism. And we executed a simulation and analyzed the throughput and packet drop rate based on the Sending Drop Precedence changing dynamically depending on the network traffic. The results show that the proposed mechanism provides better performance on drop precedence levels and stricter drop precedence policy for AF class.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.547-554
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• 2002

This paper proposes an efficient dynamic routing algorithm for Multistage Bus Networks(MBN's) in distributed shared memory environment. Our algorithm utilizes extra paths available on MBN and determines routing paths adaptively according to switch traffic in order to distribute traffic among switches. Precisely, a packet is transmitted to the next switch on an extra path having a lighter traffic. As a consequence the proposed algorithm reduces the mean response time and the average number of waiting tasks. The results of simulations, carried out with varying numbers of processors and varying switch sizes, show that the proposed algorithm improves the mean response time by 9% and the average number of waiting tasks by 21.6%, compared to the existing routing algorithms which do not consider extra paths on MBN.

• Journal of Korea Game Society
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• v.19 no.1
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• pp.5-14
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• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.10
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• pp.27-35
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• 2018

In this paper, a fundamental study for developing and introducing a new assessment method of the 'Energy Performance' in G-SEED that uses dynamic building energy simulations was conducted by comparing and analyzing the corresponding issues of domestic and foreign green building certification systems. The most significant part of the new assessment method to be developed was a development of a modeling guideline for a reference building using dynamic building energy simulations. In this paper, the composition and detailed contents of the guideline was created to comply with domestic energy codes. In addition, one of the most influential part of the result in the simulations, the 24-hour building operation schedule for a reference building, was created considering the equity with the ECO2 program that is the evaluation tool of one of the current assessment methods in the "Energy Performance". In order to improve the completeness of this guideline, it is necessary to continue the process of supplementation in the future, however, this paper is expected to be of great significance as the beginning of the research.

• Annual Conference of KIPS
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• 2010.04a
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• pp.523-526
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• 2010

주어진 경계선에 대해 비누막이 생성하는 표면 모델링 및 시간에 따른 변형 시뮬레이션은 컴퓨터 그래픽스 응용 프로그램의 한 분야이다. 이 문제에 대한 이전의 연구들은 주로 기하적인 방법들을 이용하였기 때문에 물리적으로 정확한 변형을 다루지 못하였다. 본 연구에서는 정확한 기하를 바탕으로 물리기반 변형을 다루기 위해 이산미분기하학으로부터 비누막의 동적인 모델을 제안한다. 우선, 비누 성분의 물리적인 특성들을 고려한 에너지 모델을 정의하고, 이를 이산 영역에서 나타내기 위해 이산미분기하 및 이산화 기법들을 이용한다. 제안하는 모델은 평형 상태에서의 비누막 형상뿐만 아니라 외력에 대한 표면의 변형까지 정확하게 나타내며, 실시간 시뮬레이션이 가능하여 게임, 애니메이션 목적으로 활용될 수 있다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.504-507
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• 2002

취약성 진단을 위한 시뮬레이션 시스템의 주요 구성 요소인 네트워크 모델의 설계 및 구현을 소개한다. 특히, 네트워크에 존재하는 취약점을 진단, 분석하기 위한 모델링 방법론을 제시하고, 구체적인 모델의 설계와 구현을 수행하였다. 네트워크 모델은 네트워크 구성요소인 허브, 라우터 및 네트워크 호스트들을 추상화한 모델들의 결합(Coupling) 형태로 구성되며, 각 구성 요소들은 각자의 취약성을 가지고 있다. 본 연구에서는 이러한 각 구성요소의 취약성의 집합으로 네트워크를 표현하고, 취약성을 기반으로 한 네트워크 모델의 구조적인 특성과 동적인 특성을 제시한다. 취약성 진단을 위해 제시된 모델링 방법을 통해 구현된 네트워크 모델은 시뮬레이션 실행을 통해 분석되어 그 유효성을 검증하였다.