• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.869-874
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• 2001

In order that precision equipment using high precision industrial operate normally. vibration criteria of expected area that equipment be set up is micrometer level. that method is a trust design for apply to in field, when there attend to quantifiable method. Hence, semi -empirical method that using on the basis of experimental data about undefined information (properities of vibration source, dynamic properities of structure, etc.,) for prediction of vibration response make the use of dynamic structure design of semiconductor ＆ TFT-LCD in the inside and outside country. Like this, for doing an optimal design of dynamic about structure, it is best important to get trust data that apply to semi-empirical method that is method of prediction vibration level. In this paper, on the basis of experimental data which was offered by a manufacturing company Of precisin equipment that plan to set up in semiconductor factory, we predicted vibration response on expected area that equipment be set up.

• 대한기계학회논문집B
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• 제26권7호
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• pp.945-950
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• 2002

Shape optimization of a flow system is done to obtain the required effects, in the engineering fields. Most of these designs are accomplished by empirical or numerical analysis. In empirical analysis, it is difficult to obtain an optimal shape in the feasible design region. And, in numerical method, it usually needs much calculation expenses for shape optimization, because of design sensitivity analysis. In this study, we used the growth-strain method having only one distributed parameter such as a design variable. It optimizes a shape by making a distributed parameter such as dissipation energy uniform in a flow system, and then applied to two-flow systems. In order to overcome the stability occurred in numerical analysis performed by Azegami, the equation of volumic strain has been modified. Also, the shapes were compared with the known optimal shapes for the flow systems. Consequently, we confirm that the modified growth-strain method is very efficient and practical in shape optimization of the flow systems.

• 응용통계연구
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• 제19권2호
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• pp.319-330
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• 2006

현실세계에서 관찰되는 시그널(signal)은 다양한 주파수(frequency)들의 시그널로 혼합되어 있는 경우가 많다. 예를 들어 태양 흑점 자료의 경우 약 11년 주기와 85년 주기로 변동한다는 사실은 널리 알려져 있다. 또한 경제 시계열 자료의 경우는 통상적으로 계절요인(seasonal component), 순환요인(cyclic component) 그리고 장기적인 추세요인(long-term trend)으로 분해하여 분석한다. 이러한 시계열 자료를 구성요소별로 분해하는 것은 오래된 주제중 하나이다. 전통적인 시계열자료 분석기법으로 스펙트럴 분석기법 등이 널리 사용되고 있으나 시계열 자료들이 비정상(nonstationary)일 경우에는 적용하기 어렵다. Huang et. al(1998)은 경험적 모드분해법(empirical mode decomposition)이라고 하는 자료적응적인(data-adaptive) 방법을 제안하였는데, 비정상성(nonstationarity)에 대한 강건성(robustness)으로 여러 분야에 널리 응용되고 있다. 그러나 Huang et. at(1998)은 잡음(error)에 의해 오염된 자료에 대한 구체적인 처리방법은 제시하지 못하고 있다. 본 논문을 통하여 효율적인 잡음제거 방법을 제안하고자 한다.

• 한국전산구조공학회논문집
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• 제18권3호
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• pp.245-254
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• 2005

방사성물질은 다양한 분야에서 사용되고 있으며 이에 따른 국내 및 국제간 운반이 계속적으로 증가하고 있다. 방사성물질을 수송하기 위해서는 수송용기의 안전성이 확보되어야 한다. 방사성물질 수송용기의 안전규정에 관해서는 국내 원자력법 운반안전규정 및 IAEA 운반규정에서 규정하고 있다. 방사성물질 수송용기 중에서 사용후핵연료를 운반하는 수송용기는 본체와 충격완충제로 구성되어 있다. 본 논문에서는 사용후핵연료 수송용기의 충격완충제에 작용하는 충격력을 계산하는 간편한 실험식을 차원해석을 통하여 유도하였다. 해석결과는 기존의 충격면적법 및 유한요소해석과 비교를 통하여 그 타당성을 입증하였다. 본 실험식을 이용하여 수송용기의 낙하충격력을 쉽게 예측할 수 있다.

• 한국지반환경공학회 논문집
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• 제7권2호
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• pp.25-32
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• 2006

변형계수는 터널의 안정성 검토나 지보시스템 계산의 중요한 변수이다. 현장조건을 고려한 현장시험을 통한 변형계수 추정은 많은 비용과 시간이 소요됨으로 현장 암반의 절리 특성 등을 고려할 수 있는 RQD, RMR 등을 이용한 경험적인 제안식들이 주로 이용된다. 그러나 이들 제안식들은 대부분이 해외 사례연구를 통한 경험식으로서 이러한 식들로는 국내 암반의 강도 및 변형특성에 맞는 변형계수를 추정에는 제한이 있을 것으로 사료된다. 따라서 본 연구에서는 국내 8개 현장에서 실시한 공내재하시험 결과를 이용한 측정값을 RMR 값을 이용한 기존 이론식으로부터 산정된 추정값과 비교하여 국내 현장에서의 적용성을 평가하였다. 분석결과, 암종별로 변형계수와 RMR 값의 상관관계가 뚜렷하게 나타나는 경우도 있는 반면에 자료의 분산이 매우 불규칙한 경우도 있어 기존 이론식의 적용에 있어 어려움이 있었다. 따라서 향후 국내 현장조건에 맞는 적절한 추정식이 제안되어야 한다고 사료된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(1)
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• pp.333-338
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• 1995

This paper discusses the methods for building up the empirical CHF correlation, Direct Substitution Method (DSM) and Heat Balance Method (HBM). It also includes consideration on the CHF manin, which ran be expressed differently depending on the correlation types in use. Some findings an presented with exemplary calculation.

• 대한조선학회논문집
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• 제53권1호
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• pp.62-68
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• 2016

A simple calculation tool for added resistance in waves is developed to utilize for initial design or embedded module for navigation support system. In order to select an appropriate calculation method for added resistance in waves, three methods (drift method, integrated pressure method, radiated energy method) based on strip method are applied to Wigley I and KVLCC2. The methods for added resistance in waves give the underestimated results because it is difficult to consider nonlinear effects due to reflected wave. We apply asymptotic (Faltinsen's method) and empirical formula (NMRI's method) to improve the accuracy for short wave length region. In comparison with experimental results, the combination of radiated energy method and short wave correction method of NMRI is the most reasonable. However, a simple sum of results calculated by two methods gives rise to the overestimation of added resistance for short wave length region because added resistance of radiated energy method exits in total reflection region. To overcome this problem, modified radiated energy method is proposed using correction coefficient defined by reflection coefficient of NMRI's method. Finally, added resistance in regular waves is composed of added resistance of modified radiated energy method and that of short wave correction method of NMRI. Estimated added resistance in regular waves is validated by comparison with experimental results of other research groups.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.365-368
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• 2003

Despite of the simple equipment and operation, DMT has been widely used to obtain various soil parameters and those parameters have been successfully applied to geotechnical design practice. Among them, the estimation of horizontal coefficient of consolidation is so useful that many researchs recently have been carried out. However, simulation of the penetration of the DMT blade is complex due to the inherent difficulty on analyzing a plane strain deformation of the soil around blade. Therefore, empirical and semi-empirical methods that use the theoretical solution developed fur piezocone with some assumptions have been used to estimate the coefficient of consolidation from Dilatometer dissipation test. In this paper, coefficients of consolidation c$\_$h/ which were obtained using equivalent radius that is same area with the DMT blade and optimization technique are compared with those obtained from Oedometer test and other interpretation methods. It was found that a new method used in this study can give more precise horizontal coefficient of consolidation than other methods do.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1830-1835
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• 2003

A novel index representing burden distribution form in the blast furnace is developed and index estimation model is built with an empirical modeling method to monitor inner condition of the furnace without expensive sensors. To find the best combination of index and modeling method, two candidates for the index and four modeling methods have been examined. Results have shown that 3-D index have more resolution in describing the distribution form than 1-D index and ANN model produces smallest RMSE due to nonlinearity between the indices and charging mode. Although ANN has shown the best prediction accuracy in this study, PLS can be a good alternative due to its advantages in generalization capability, consistency, simplicity and training time. The second best result of PLS in the prediction results supports this fact.

• Journal of Communications and Networks
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• 제16권1호
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• pp.92-97
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• 2014

A novel method for extracting frequency slippage signal from radar full pulse sequence is presented. For the radar full pulse sequence received by radar interception receiver, radio frequency (RF) and time of arrival (TOA) of all pulses constitute a two-dimensional information sequence. In a complex and intensive electromagnetic environment, the TOA of pulses is distributed unevenly, randomly, and in a nonstationary manner, preventing existing methods from directly analyzing such time series and effectively extracting certain signal features. This work applies Gaussian noise insertion and structure function to the TOA-RF information sequence respectively such that the equalization of time intervals and correlation processing are accomplished. The components with different frequencies in structure function series are separated using empirical mode decomposition. Additionally, a chaos detection model based on the Duffing equation is introduced to determine the useful component and extract the changing features of RF. Experimental results indicate that the proposed methodology can successfully extract the slippage signal effectively in the case that multiple radar pulse sequences overlap.