• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.51-55
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• 1995

An adaptive unified predictive control (UPC) algorithm is applied to a batch polymerization reactor for poly(methyl methancrylate) (PMMA) and the effects of controller parameters are investigated. Computational studies are performed for a batch polymerization system model developed in this study. A transfer function in parametric form is estimated by recursive least squares (RLS) method, and the UPC algorithm is implemented to control the reactor temperature on the basis of this transfer function. The adaptive unified predictive controller shows a better performance than the PID controller for tracking set point changes, especially in the latter part of reaction course when gel effect becomes significant. Various performance can be acquired by selecting adequate values for parameters of the adaptive unified predictive controller; in other words, the optimal set of parameters exists for a given set of reaction conditions and control objective.

• 한국가시화정보학회지
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• 제13권3호
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• pp.24-28
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• 2015

The temperature of the wafer batch in the furnace was calculated and its visualized temperature field was analyzed. The main heat transfer mechanisms from the heater wall to the wafers were radiation and conduction, and the finite difference method was used to analyze the complex heat transfer including those two mechanisms. The visualized temperature field shows that the direction of the heat flux in the wafer batch varies during the heating process, and the heat in the wafer batch diffuses faster by conduction within the wafer than by radiation between the wafers, in the condition of the constant temperature at the heater wall and cap.

• 정보보호학회논문지
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• 제20권1호
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• pp.17-31
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• 2010

VANET(Vehicular Ad hoc NETwork)에서 차량들은 일괄 확인(batch verification) 기법을 이용해 많은 수의 서명 메시지를 효율적으로 검증할 수 있다. 하지만 각 차량에서의 개별적인 일괄 확인은 네트워크 전체적으로 볼 때 불필요한 중복 검증을 발생시킨다. 이 문제를 해결하기 위해 RSU(Road Side Unit)가 노드를 대신해서 일괄 확인을 수행 할 수 있지만, 이 방법은 일괄 확인이 실패했을 경우 유효하지 않은 서명을 효율적으로 찾을 수 있는 방법이 추가적으로 필요하다. 본 논문에서는 분산 일괄 확인 시스템을 설계하기 위해 고려되어야하는 몇 가지 방법론에 대해서 분석하고 참여 차량이 작은 크기의 서명 집합을 분산해서 일괄 확인하는 효율적인 분산 일괄 확인 시스템을 제안한다. 제안하는 시스템에서 각 노드는 RSU에게 단순 일괄 확인 결과만을 보고하거나 식별한 유효하지 않은 서명들을 보고할 수 있으며 이를 수신한 RSU는 노드의 이 일괄 검증 결과 리포트를 이용하여 효율적으로 유효하지 않은 서명을 식별하여 배제할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.263-266
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• 1996

A method to determine an optimal temperature trajectory that guarantees polymer products having controlled molecular weight distribution and desired values of molecular weight is presented. The coordinate transformation method and the optimal control theory are applied to a batch PMMA polymerization system to calculate the optimal temperature trajectory. Coordinate transformation method converts the original fixed-end-point, free-end-time problem to a free-end-point, fixed-end-time problem. The idea is that by making the reactor temperature track the optimal temperature trajectory one may be able to produce polymer products having the prespecified physical property in a minimum time. The on-line control experiments with the PID control algorithm have been conducted to establish the validity of the scheme proposed in this study. The experimental results show that prespecified polymer product could be obtained with tracking the calculated optimal temperature trajectory.

• International journal of advanced smart convergence
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• 제5권3호
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• pp.40-46
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• 2016

The internet allows the information to flow at anywhere in anytime easily. Unfortunately, the network also becomes a great tool for the criminals to operate cybercrimes such as identity theft. To prevent the issue, using a very complex password is not a very encouraging method. Alternatively, keystroke dynamics helps the user to solve the problem. Keystroke dynamics is the information of timing details when a user presses a key or releases a key. A machine can learn a user typing behavior from the information integrate with a proper machine learning algorithm. In this paper, we have proposed mini-batch ensemble (MIBE) method which does the preprocessing on the original dataset and then produces multiple mini batches in the end. The mini batches are then trained by a machine learning algorithm. From the experimental result, we have shown the improvement of the performance for each base algorithm.

• 한국지반환경공학회 논문집
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• 제4권3호
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• pp.61-67
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• 2003

축산폐수를 처리 시 우선 탈수 후 고상은 퇴비화, 액상을 연속회분식반응기(Sequencing batch reactor, SBR)로 이용하여 처리하는 시스템을 구상하였다. 영양염류 제거를 위한 SBR 공정의 안정적인 운전을 위한 운전모드 결정 실험을 수행하였다. K시 공공축산폐수처리장의 원심분리기에서 나온 유출수를 사용한 실험에서 질소를 제거하기 위한 적정 fill ratio는 1/12, SRT는 15일, 폭기/비폭기 주기는 2시간/1시간이었다. 탈질을 위하여 주입한 외부탄소원으로는 메탄올을 사용하였고 single feeding 방법과 step feeding 방법을 사용하였다. 이 결과 step feeding 방법을 사용시 더 효과적으로 유기물을 사용 탈질효율을 증가시킬 수 있었다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1993년도 제3회 정기총회 및 추계학술발표회
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• pp.2-2
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• 1993

Inference for discrete event simulations usually relies on either independent replications or, if each simulation run is expensive, the method of batch means applied to a single replications. We present a new method, threshold bootstrap, which equals or exceeds the performance of independent replications or batch means. The method works by resampling runs of data created when a stationary time series crosses a threshold level, such as the sample mean of series. Computational results show that the threshold bootstrap matches or exceeds the performance of these alternative methods in estimating the standard deviation of the sample mean and producing valid confidence intervals.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.409-418
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• 2017

This work attempted to manufacture glued-laminated timber (Glulam) bonded with melamine-urea-formaldehyde (MUF) resin adhesives at various melamine contents from 20% to 50% under high frequency (HF) heating for a very short time. Two preparation methods were employed to prepare MUF resin adhesives with different melamine contents: one-batch method of synthesizing MUF resins in a single batch, and two-batch method of mixing urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized separately. As the melamine content increased, the gelation time and peak temperature of MUF resins decreased. The adhesion performance of plywood showed that the one-batch MUF resin adhesive with 50% melamine content only satisfied the standard requirement of water resistance. Thus, the one-batch MUF resin adhesive with 50% melamine content was applied for bonding wood lamina from four softwood species such as Japanese larch, Korean red pine, Korean pine and Japanese cedar to manufacture Glulam under HF heating. All Glulam samples bonded with the one-batch MUF resin adhesives with 50% melamine content except those from Korean Red Pine satisfied the requirement in water soaking or boiling water delamination test as an exterior grade Glulam. The presence of rosin in Korean Red Pine was believed to be responsible for its poor adhesion. These results showed that the one-batch MUF resin adhesives with 50% melamine content provided acceptable water resistance with exterior grade Glulam manufactured under HF heating.

• 한국가스학회지
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• 제5권1호
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• pp.21-28
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• 2001

회분식 공정의 HAZOP 분석 전문가 시스템은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 따라서 본 연구에서는 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 time과 sequence 해석을 수행하는 회분식 공정의 HAZOP 분석 자동화를 위한 전문가 시스템을 개발하였다. 제안된 전문가 시스템을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.

• 한국가스학회지
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• 제3권2호
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• pp.34-42
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• 1999

회분식 공정의 HAZOP 분석 기법은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 회분식 공정의 time과 sequence 해석은 연속 공정의 HAZOP 분석 기법으로는 설명될 수 없으므로, 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 HAZOP 분석을 수행하는 방법을 개발하였다 본 연구에서는 이 방법을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.