• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.1022-1027
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• 2001

In this study, the train-induced vibration was measured at many locations at/around the actual service lines and the data base was constructed using the measurement results. The characteristics of train induced ground vibration was categorized and the empirical ground vibration estimating equations were developed. On the ground area (level grounds, embankments, cut sections), the vibration estimating equations were developed in terms of ground vibration level which was related with the distance from the source. Especially for the cut section areas, the vibration levels were expressed with the vibration receiving point expressed by the ratio of vertical distance to horizontal distance(V/H) from the source. As a result, when V/H is 0.96, the vibration estimating equation gives a minimum vibration level.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.333-335
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• 2001

In this paper, an algorithm for fault location in Auto Transformer(AT) Feeding Railway system is presented. If a fault occurs at the AT feeding circuits of electrical railway system, it is very important to find fault location and to remove it immediately for the purpose of ensuring safety for transportation. Because the characteristics of reactance-distance are not linear, only using one terminal signals to give fault distance is difficult. In this paper, first, using the KVL, 4 voltage equation are obtained. Secondly, eliminating voltage a distance equation which consists of currents at rail and line parameters including mutual effects.

• Journal of the Optical Society of Korea
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• 제9권1호
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• pp.6-12
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• 2005

The perturbation approach is applied to solve the nonlinear Schrodinger equation, and its valid range has been determined by comparing with the results of the split-step Fourier method over a wide range of parameter values. With γ= 2㎞/sup -1/mW/sup -1/, the critical distance for the first order perturbation approach is estimated to be(equation omitted). The critical distance, Z/sub c/, is defined as the distance at which the normalized square deviation compared to the split-step Fourier method reaches 10/sup -3/. Including the second order perturbation will increase Z/sub c/ more than a factor of two, but the increased computation load makes the perturbation approach less attractive. In addition, it is shown mathematically that the perturbation approach is equivalent to the Volterra series approach, which can be used to design a nonlinear equalizer (or compensator). Finally, the perturbation approach is applied to obtain the sinusoidal response of the fiber, and its range of validity has been studied.

• 산업융합연구
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• 제1권2호
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• pp.17-31
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• 2003

Many risk factors with the onset of Low Back Pain(LBP) have been identified, however, lifting out of Manual Material Handling(MMH) was the most important factor to the LBP. Injuries due to lifting took account for 34.0%(227,291) out of the total overexertion in MMH(668,084). The weight, vertical location, twist angle, lifting frequency, and lifting posture were reviewed in this study. Technical information for using the revised lifting equation to evaluate a variety of two - handled manual material handling tasks was suggested. To measure worker's fatigue in lifting task, Lifting Index Simulator(LIS) was create under the revised NIOSH(National Institute for Occupational Safety and Health) lifting equation. For the implementation of the LIS, data was collected in A company manufactures various paints in Si-Wha industrial complex, Kyunggi-Do. The results of the Lifting Index(LI) were analyzed by MANOVA to find the relation with lifting variables collected. It was found that horizontal distance, vertical distance, travelling distance and frequency were significant at the 0.01 level and weight was significant at the 0.05 level. The purpose of this paper is to reduce the chronical low back pain for the manual material handlers.

• Journal of the Optical Society of Korea
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• 제13권3호
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• pp.379-385
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• 2009

The vergence control of binocular stereoscopic camera is the most essential factor for acquiring high quality stereoscopic images. In this paper, we proposed a binocular stereoscopic camera vergence control method using disparity information by the simple image processing and estimate the quantity of vergence control using the Lagrange interpolation equation. The method of extracting disparity information through image processing is as follows: first the key-object in left & right images was extracted through labeling of the central area of the image, and then a simple method was used for calculating the disparity value of the same key-object in the labeled left and right images. The vergence control method uses disparity information and keeps the convergence distance of left & right cameras and the distance of the key-object the same. According to the proposed method, variance in the distance of the key-object and application of calculated disparity information of obtained left & right images to the quadratic Lagrange interpolation equation could estimate the quantity of vergence control, which confirmed that the method of stereoscopic camera vergence control can be simplified through experiments on various key-objects and other convergence distance.

• Earthquakes and Structures
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• 제10권2호
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• pp.389-408
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• 2016

Recently, seismic hazard analysis has become a very significant issue. New systems and available data have been also developed that could help scientists to explain the earthquakes phenomena and its physics. Scientists have begun to accept the role of uncertainty in earthquake issues and seismic hazard analysis. However, handling the existing uncertainty is still an important problem and lack of data causes difficulties in precisely quantifying uncertainty. Ground Motion Prediction Equation (GMPE) values are usually obtained in a statistical method: regression analysis. Each of these GMPEs uses the preliminary data of the selected earthquake. In this paper, a new fuzzy method was proposed to select suitable GMPE at every intensity (earthquake magnitude) and distance (site distance to fault) according to preliminary data aggregation in their area using ${\alpha}$ cut. The results showed that the use of this method as a GMPE could make a significant difference in probabilistic seismic hazard analysis (PSHA) results instead of selecting one equation or using logic tree. Also, a practical example of this new method was described in Iran as one of the world's earthquake-prone areas.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2002년도 춘계 학술발표회 논문집
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• pp.45-48
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• 2002

Consider the mean distance of Brownian motion on Riemannian manifolds. We obtain the first three terms of the asymptotic expansion of the mean distance by means of Stochastic Differential Equation(SDE) for Brownian motion on Riemannian manifold. This method proves to be much simpler for further expansion than the methods developed by Liao and Zheng(1995). Our expansion gives the same characterizations as the mean exit time from a small geodesic ball with regard to Euclidean space and the rank 1 symmetric spaces.

• Korean Journal of Mathematics
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• 제30권4호
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• pp.571-592
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• 2022

By established a Banach space with the Hausdorff distance, we introduce the alternative fixed-point theorem to explore the existence and uniqueness of a fixed subset of Y and investigate the stability of set-valued Euler-Lagrange functional equations in this space. Some properties of the Hausdorff distance are furthermore explored by a short and simple way.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.421-435
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• 1998

An empirical formula for estimating duration magnitude(MD)is determined by analyzing 619 epicentral distance-duration data set, obtained from earthquakes of 1989-1998 recorded at the KMA network. Based on two assumptions: 1) observed signal duration decreases with increasing epicentral distance, and 2) seismographs of KMA are set at low-gain and therefore inclusion of sensitivity correction term in the equation is not necessary, scaling predicted duration at epicenter to Tsuboi's local magnitude yielded the duration magnitude equation: MD =2.0292$\times$log$\tau$＋0.00123Δ-1.4017 for 1/0$\leq$ML$\leq$5.0, where $\tau$is total signal duration(sec)and Δis epicentral distance(km). Event by event comparison of ML values against MD estimates for t152 events shows that for events having a same ML the difference in MD estimates reaches as high as 1.1 magnitude units. So, to test the usefulness of the duration magnitude equation, we have calculated ML-MD relations by which duration magnitude estimates are converted to local magnitudes ("predicted" ML, say) which are then compared with the directly determined local magnitude values. Except for events with stations where duration is anomalously reestimates(predicted ML) which are in an agreement within a 0.2 magnitude units with the corresponding ML values. Although this study could gain some insights into magnitudes of the past events, we still need to re-examine all the observables in order to obtain more reliable and precise information about magnitude and hypocenter location. So we will pursue a new local-magnitude scaling, as well as refinement of the duration magnitude equation, starting soon with re-reading the amplitudes-arrival time records of (and hence relocating) 250+earthquakes of 1979-present recorded at the KMA network. Thus, with more reliable and precise earthquake parameters determined we would better understand the recent seismicity and related tectonic process within and adjacent region to the Korean peninsula.peninsula.

• 대한전자공학회논문지SP
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• 제39권2호
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• pp.147-154
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• 2002

본 논문에서는 multimodal 특성을 갖는 데이터에 대하여 패턴 분류 시 Bhattacharyya distance에 기반한 에러 예측 기법을 제안한다. 제안한 방법은 multimodal 데이터에 대하여 분류 에러와 Bhattacharyya distance를 각각 실험적으로 구하고 이 둘 사이의 관계를 유추하여 에러의 예측 가능성을 조사한다. 본 논문에서는 분류 에러 및 Bhattacharyya distance를 구하기 위하여 multimodal 데이터의 확률 밀도 함수를 정규 분포 특성을 갖는 부클래스들의 조합으로 추정한다. 원격 탐사 데이터를 이용하여 실험한 결과, multimodal 데이터의 분류 에러와 Bhattacharyya distance 사이에 밀접한 관련이 있음이 확인되었으며, Bhattacharyya distance를 이용한 에러 예측 가능성을 보여주었다.