• Convergence Security Journal
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• 제14권2호
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• pp.43-50
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• 2014

Recently, lot of researches for the multi-level protocol have been done to balance the sensor node energy consumption of WSN and improve the node efficiency to extend the life of the entire network. Especially in multi-hop protocol, a variety of models have been proposed to improve energy efficiency and apply it to WSN protocol. In this paper, we analyze LEACH algorithm and propose new method based on center of local clustering routing algorithm in wireless sensor networks. We also perform NS-2 simulation to show the performance of our model.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.64.2-64.2
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• 2011

a-Si 박막 태양전지는 a-Si:H을 유리 기판 사이에 주입해 만드는 태양전지로, 뛰어난 적용성과 경제성을 지녔으나 c-Si 태양전지에 비해 낮은 변환 효율을 보이는 단점이 있다. 변환 효율을 높이기 위한 연구 방법으로는 a-Si 박막 태양전지 단일cell 제작 시 high Bandgap을 가지는 p-layer를 사용함으로 높은 Voc와 Jsc의 향상에 기여할 수 있는데, 이 때 p-layer의 defect 증가와 activation energy 증가도 동시에 일어나 변환 효율의 증가폭을 감소시킨다. 이를 보완하기 위해 본 실험에서는 p-layer에 기존의 p-a-Si:H를 사용함과 동시에 high Bandgap의 buffer layer를 p-layer와 i-layer 사이에 삽입함으로써 그 장점을 유지하고 높은 defect과 낮은 activation energy의 영향을 최소화하였다. ASA 시뮬레이션을 통해 a-Si:H보다 high Bandgap을 가지는 a-SiOx 박막을 사용하여 p-type buffer layer의 두께를 2nm, Bandgap 2.0eV, activation energy를 0.55eV로 설정하고, i-type buffer layer의 두께를 2nm, Bandgap 1.8eV로 설정하여 삽입하였을 때 박막 태양전지의 변환 효율 10.74%를 달성할 수 있었다. (Voc=904mV, Jsc=$17.48mA/cm^2$, FF=67.97).

• Journal of Navigation and Port Research
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• 제35권3호
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• pp.235-241
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• 2011

The shuttle that currently connects Busan New Port to the logistics companies in the Hinterland has the following companies: first, resources are consumed redundantly as each logistics company has independent transport vehicles. Second, the companies are not taking advantage of geographical merits of clustered complexes because different vehicles are used each time due to irregular schedules. In this respect, this study had the following purposes to realize these solutions: first, heuristic approach was made for operation scheduling and real-time operating rules to configure the best possible dynamic plan. Second, the reduction of consumption of resources with the shuttle and the efficiency were examined through a simulation of pooling and dual cycling applied to logistics companies' shipping plans.

• Journal of the Korea Society for Simulation
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• 제15권3호
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• pp.61-67
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• 2006

This paper provides a systematic way of integrating human intelligence and autonomous precision of robots to achieve the highest possible performance of a cooperating robot system. Adjustable autonomy, which deals with the combination of human and robotic skills, has the potential to bridge the gap which leaves many tasks suited to robotics beyond the reach of existing technology. Especially we will show that relevant human assistance or intervention will increase system performance by improving the exception handling capability, simplifying autonomous operation, and boosting speed and reliability. To support the usefulness of our scheme, a series of experiments were conducted with three cooperating robots which work together to dock both ends of a long suspended beam into stanchions.

• The KIPS Transactions:PartD
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• 제16D권6호
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• pp.921-926
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• 2009

Vulnerabilities in software can result in many social and economic problems once it has already been deployed and put to use. Thus, the vulnerabilities should be seriously taken into consideration from the beginning step of software development. A modeling and simulation method for software can be adopted as a testing tool for establishing vulnerability inspection strategies. For verification of usability of this strategy, in this paper, we modeled the behavior of a DNS system using Ptolemy and the simulation was performed. The result shows that a well-known vulnerability of DNS server could be effectively found, which confirms that the modeling and simulation can be used for vulnerability testing.

• The Transactions of the Korea Information Processing Society
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• 제7권9호
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• pp.3002-3010
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• 2000

ATM forum defined several ATM oriented services such as ABR, VBR, CBR, UBR, and others. Among them, ABR service is considered as one of the most appropriate ones in the LAN environment. ABR controls network traffic by using RM cells according to ATM forum standard. In particular, the point-to-multipoint ABR service in general uses consolidation algorithms to solve feedback implosion at the branch point. Consolidation algorithms alleviate propagation delay and network congestion problem: thus, the efficiency of consolidation algorithm is closely related to the network performance. In this paper, we describe the limitation of existing consolidation algorithms based on thorough analysis, and then propose an algorithm that performs better than the existing algorithms. We show that the proposed algorithm improves network performance through a parametric simulation, In our simulation the performance measure is the cell rate which is controlled by exploiting the congestion depth. We also found that the proposed algorithm not only improves efficiency of network, but also eliminates the consolidation noise.

• Journal of the Korea Computer Graphics Society
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• 제25권3호
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• pp.105-113
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• 2019

Physically-based fluid simulation takes a lot of time for high resolution. To solve this problem, there are studies that make up the limitation of low resolution fluid simulation by using deep running. Among them, Super-resolution, which converts low-resolution simulation data to high resolution is under way. However, traditional techniques require to the entire space where there are no density data, so there are problems that are inefficient in terms of the full simulation speed and that cannot be computed with the lack of GPU memory as input resolution increases. In this paper, we propose a new method that divides and classifies 2D smoke simulation data into the space using the quad tree, one of the spatial partitioning methods, and performs Super-resolution only required space. This technique accelerates the simulation speed by computing only necessary space. It also processes the divided input data, which can solve GPU memory problems.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권10호
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• pp.1752-1758
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• 2006

Racing game requires plausible physics model that can be simulated in realtime. Minor artifacts in racing games are easily noticed, and any kinds of games should work interactively. It is difficult to model the accurate tire-ground physics and to integrate the model into realtime environments. In this paper, an efficient and effective 'imaginary wall' model was proposed. The method can be easily implemented because of the simplicity of the physical model used, and the result of the simulation is realistic enough for the racing games.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 대한산업공학회/한국경영과학회 2000년도 춘계공동학술대회 논문집
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• pp.433-436
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• 2000

경제가 고도로 성장하던 단계에서는 기업은 사업규모도 크지 않고, 경쟁환경도 치열하지 않았을 뿐 아니라 내·외부적인 환경도 안정적이기 때문에 양적 확대에만 집중하더라도 그것이 기업가치를 크게 하는 역할을 할 수 있었다. 그러나 내·외부적인 무수한 환경변화와 경쟁격화로 인하여 수익성의 악화가 반복되는 현실에서는 종전과 같은 경영사고나 전략으로는 새로운 환경에서 살아남을 수 없을 것이다. 따라서 본 논문은 기업들의 환경변화에 따른 대처능력과 의사결정을 원활히 하기 위해 기존의 단순 수치의 변환에 의해서 결과를 도출하는 회계 시뮬레이션에서 벗어나 회귀분석과 신뢰구간을 사용하여 기업의 의사결정에 있어서 보다 기업의 현실에 근접한 데이터를 추출하여 의사결정의 원활화를 도모하고자 하였으며 최종 시뮬레이션 결과를 EVA 에 둠으로써 기업의 수익성, 자본효율도 등의 기업가치를 여러 방면으로 추정할 수 있도록 하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 한국컴퓨터정보학회 2022년도 제66차 하계학술대회논문집 30권2호
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• pp.567-568
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• 2022

헤어 시뮬레이션은 수많은 가닥으로 구성되어 있으며, 헤어 동역학을 기반으로 계산되기 때문에 일반적으로 계산양이 큰 범주에 속한다. 뿐만 아니라 곱슬머리 형태를 유지하려는 제약은 더 큰 계산을 요구하며, 본 논문에서는 수분에 의해 곱슬머리가 젖었을 때 표현되는 구부러짐과 수축을 모델링 할 수 있는 새로운 알고리즘을 제시한다. 이전 연구에서는 곱슬머리에 대한 헤어 시뮬레이션은 곱슬머리의 회전(Curl)형태를 유지하려는 알고리즘을 제안했지만, 강한 외력에 의한 회전형태만을 유지하려고 했으며, 수분이나 열에 의한 곱슬머리의 상태변화는 고려하지 못했다. 따라서 본 논문에서는 IIR(Infinite impulse response) 필터로 스무딩된 헤어 커브를 따라 회전의 수직 성분을 추출하여 회전의 세로방향 신축성을 제어할 수 있는 방법을 제안한다. 우리의 헤어 모델은 곱슬머리의 회전과 신축성을 제어하기 위해 스프링 동역학을 사용하며, 젖은 헤어의 부분적인 상태 변화에도 안정적으로 표현할 수 있음을 보여준다.