• Journal of the Korea Society of Computer and Information
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• 제5권4호
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• pp.90-95
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• 2000

In order to enhance the confidence in the mobile communication and improve the performance of the bit error, we have been using coding method. In the case of this, we have to add redundancy bits by using error correcting codes such as the block or convolutional codes. However, the result of redundancy bits causes to improve confidence. but to drop the efficiency in the bandwidth. We have studied coding method that we are able to get the good coding gain without any changes in the data transmission rates in the limited bandwidth. In this Paper, we design TCM(Trellis Coded Modulation) which was proposed by Ungerboeck and MTCM(Multiple TCM), with multiplicity(k＝2), which was proposed by Divsalar, using the optimum encoder. As state number is varied in the optimum encoder, we compare the performance of the TCM and MTCM by using Monte Carlo simulation.

• Journal of the Earthquake Engineering Society of Korea
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• 제7권2호
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• pp.93-102
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• 2003

A technique for the seismic reliability evaluation of electric power transmission network system(EPTS) was developed to evaluate reliability indices corresponding to the whole network system and to each node within. A network model with nodes and links for EPTS was established, and a seismic substation fragility curve obtained from seismic fragilities of power system facilities was derived. A point source model, the doubly truncated Gutenberg-Richter relationship, and earthquake intensity attenuation formula was applied to simulate seismic events. Using Monte-Carlo simulation method, the seismic reliability of EPTS was evaluated and, it appeared that seismic effect on EPTS of korea has to be considered.

• The Transactions of the Korean Institute of Electrical Engineers A
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• 제55권1호
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• pp.45-51
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• 2006

This paper proposes a method to evaluate the Total Transfer Capability (TTC) by considering uncertainty of weather conditions. TTC is limited not only by the violation of system thermal and voltage limits, but also restricted by transient stability limit. Impact of the contingency on the power system performance could not be addressed in a deterministic way because of the random nature of the system equipment outage and the increase of outage probability according to the weather conditions. For these reasons, probabilistic approach is necessary to realize evaluation of the TTC. This method uses a sequential Monte Carlo simulation (MCS). In sequential simulation, the chronological behavior of the system is simulated by sampling sequence of the system operating states based on the probability distribution of the component state duration. Therefore, MCS is used to accomplish the probabilistic calculation of the TTC with consideration of the weather conditions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 2010년도 정기 학술대회
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• pp.620-623
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• 2010

구조요소의 설계에서 유한요소해석은 매우 효과적인 방법이며 정확한 해석 기술을 요구한다. 그러나 제조 공정이나 환경에 따라 달라지는 재료 물성이나 불확실성을 내포하는 피로 물성을 확정적인 값으로 이용하는 등 입력 변수의 부정확한 정보로 인해 유한요소해석 결과를 신뢰하지 못하는 경우가 자주 발생한다. 실제 시험을 통해 설계의 결과를 예측하는 것은 경제적인 측면과 시간소요 면에서 한계가 따르기에 신뢰할 수 있는 유한요소해석 방법이 요구된다. 본 연구에서는 고주기의 피로 해석을 위해 유한요소해석을 이용하여 스프링의 응력-수명(S-N) 파라미터를 역 추정하고 수명을 예측해 보았다. 이를 위해 실제 산업현장에서 쓰이는 자동차 서스펜션 코일 스프링을 예제로 사용하였다. 시험 모델에 대해 불확실성을 고려한 베이지안 접근법을 이용하여 입력변수의 파라미터를 역 추정하였으며, 마코프체인몬테카를로(Markov Chain Monte Carlo) 기법을 이용하여 얻어진 피로 물성 파라미터의 샘플 데이터를 이용해서 유한요소해석을 실시하고 신뢰수준 내에서 새로운 구조요소의 피로수명을 예측하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제49권3호
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• pp.197-204
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• 2021

If a failure or an abnormal maneuver occurs during the flight test of a missile, the missile is deliberately self-destructed so as not to continue the flight. At this time, debris are produced and it is important to estimate the impact area in real-time whether it is out of the safety area. In this paper, we propose a method to estimate the debris dispersion area and falling time in real-time using a Fully-Connected Neural Network (FCNN). We applied the Unscented Transform (UT) to generate a large amount of training data. UT parameters were selected by comparing with Monte-Carlo (MC) simulation to secure reliability. Also, we analyzed the performance of the proposed method by comparing the estimation result of MC.

• Journal of radiological science and technology
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• 제45권5호
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• pp.433-438
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• 2022

Targeted radionuclides treatment (TRT) requires the establishment of treatment plans that consider various factors, such as the type of radionuclides, target organs, and administration methods. For this reason, in this study, the absorption dose of a single cell was analyzed according to the type of radioisotope used to treat target radionuclides. In this study, a simulation was performed on beta rays used in the treatment of target radionuclides at the cell level using MCNPX (ver. 2.5.0). First, according to the calculation formula, the beam path according to the type of radioisotope for treatment was calculated. Second, the amount of self-radiation by beta rays emitted from cell diameters of 5 ㎛ and 10 ㎛ cell nuclei was evaluated. As a result, it showed a high range proportional to the maximum energy of the beta-ray, and the highest self-dose distribution from 177 Lu radiation sources among therapeutic radioisotopes. This was analyzed as a result that is inversely proportional to the maximum energy of the beta-ray, and it suggests that the selection of a nuclide considering the range of the beta-ray is necessary in the treatment of target radionuclides in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제28권4A호
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• pp.431-438
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• 2008

An updated Monte Carlo procedure for Typhoon simulation is presented to estimate the extreme wind speed at typhoon prone southern and western coasts in Korea. The reconstructed wind field model for typhoon in this study is compared with measured typhoon data for validation. The fitness of the proposed probability distribution models for typhoon parameters are tested by using data for the typhoon passed near the specific site. The simulated maximum wind speed associated with various return periods along southern and western coasts indicate that the extreme wind speed gradually increases inversely according to latitude of the coast, and that the basic wind speeds given in Korea Bridge Design Code are excessive compared with present results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2021년도 추계학술대회
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• pp.12-14
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• 2021

A sensor registry system (SRS) provides semantic metadata about a sensor based on location information of a mobile device in order to solve a problem of interoperability between a sensor and a device. However, if the GPS of the mobile device is incorrectly received, the SRS receives incorrect sensor information and has a problem in that it cannot connect with the sensor. This paper proposes a dual collaboration strategy based on geographical embedding and LSTM-based path prediction to improve the probability of successful requests between mobile devices and sensors to address this problem and evaluate with the Monte Carlo approach. Through experiments, it was shown that the proposed method can compensate for location abnormalities and is an effective multicasting mechanism.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제17권32호
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• pp.187-197
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• 1994

오늘날 소비자의 요구가 다양해지면서 여러 개의 복잡한 부품들로 이루어진 제품이 많아지게 되었다. 각각의 부품들의 공차가 제대로 결정되지 못함으로 해서 완성된 조립품의 품질이 예상외로 나빠지는 경우가 종종있다. 본 연구는 각각의 부품들의 치수 공차와 생산 공정에서 생길 수 있는 오차들을 모두 포함시켜서 완성된 조립품의 품질을 예상할 수 있는 정확한 공차 해석 방법에 대해서 연구한다. 그 방법으로 몬테카를로 시뮬레이션 방법을 소개하고 그것에 대해서 연구한다. 본 연구를 통해서 완성된 조립품의 품질 및 성능을 저하시키는 요인을 효율적으로 결정할 수 있게 된다.

• Proceedings of the KSEEG Conference
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.165-168
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• 2003

최근 사면의 안정해석분야에서 자주 사용되고 있는 확률론적 해석 방법은 현장에서 획득 되는 자료들의 분산이 심하고 충분한 양의 자료가 획득되지 못할 경우 자료 내에 포함되는 불확실성과 가변성을 효과적으로 다룰 수 있는 방법 중의 하나로 인식되어 왔다. 그러나 대개 확률론적 해석 방법에서 이용되는 몬테카를로 시뮬레이션기법(Monte Carlo simulation method)은 파괴확률을 산정하기 위하여 수 많은 반복적인 계산과정이 요구되며 따라서 많은 시간과 노력이 필요하다는 단점을 가지고 있다. (중략)