• Geotechnical Engineering
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• v.12 no.4
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• pp.5-20
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• 1996

In this study it was analyzed by 2-D FEM and 3-D FEM to evaluate the ground reinforceing effect of steel pipe reinforced multi -step grouting (SPRG) technique and the behavior of ground in the vicinity using the nonlinear FEM program for the ground condition of alluvium located on the top of tunnel applied by SPRG technique. It was found that the nonlinear 3-D analysis performed better than 2-D analysis in evaluating the usefulness of the SPRG technique, and it was also found that the safety was relatively secured by the stiffness of steel pipe to distribute the concentrated stress in the tunnel faceing. It was reported that the change of settlement on the top of tunnel becomes about 40% of the total expected settlement before tunnel faceing reaches tunnel gauging point, and 60% of the total expected settlement while tunnel facing passes tunnel gauging point and takes a distance about tunnel diameter. With the aid of the SPRG technique the control range of displacement and stress of the ground in the vicinity could be reached up to tunnel top, namely depth ratio from 0.38 to 0.83 or 2D(D : tunnel diameter) before the tunnel facing, and about 20% of settlement control in this particular case was possible.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.194-194
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• 2012

본 연구에서는 자연하천에서 Rhodamine-WT를 이용하여 추적자 실험을 수행하고 이를 바탕으로 오염사고대응예측모델에 대한 검증을 실시하고자 하였다. 최근 국내에서는 다양한 형태와 규모의 수질오염사고가 매년 수십건 이상 발생하고 있으며, 따라서 수치모형 기반의 수질오염 사고 대응 예측시스템에 대한 높은 신뢰성이 요구되고 있다. 수질사고에 노출되어 있는 지표수를 각종 용수로서 안전하게 공급하기 위해서는 정확한 수질예측이 필수적이며, 이를 위해서 수십 년간 연구되어 온 수질모델을 오염사고 대응예측시스템에 적합하도록 정확성과 신뢰성을 갖추기 위한 연구가 진행되어야 한다. 수치 모형을 이용한 물질의 이송 및 확산 모의에서는 오염물질 도달시간과 확산 농도를 결정하는 것이 가장 중요한 요소이므로 이송 및 확산 모의에 대한 검증 기법 개발 및 적용이 필요하다. 본 연구에서는 낙동강수계 지류하천인 감천에서 추적자 실험을 4회 실시하여 측정한 수리량과 농도 실측치를 이용하여 분산계수를 종 횡분산계수 산정이 가능한 2차원 유관추적법을 적용하여 산정하였다. 각 단면에 유속은 ADV-3차원 유속계인 Flow-Tracker를 사용하여 도섭으로 측정하였으며 하천의 흐름 방향의 직각으로 측선을 설치하고 펌프를 이용하여 채수를 한 다음 Rhodamie WT의 농도를 측정하였으며 측선의 위치 보정은 GPS를 통하여 보정하였다. 측정 자료를 이용하여 2차원 유관추적법으로 분산계수를 산정한 결과 각각의 측선에 따라서 다소 차이가 발생하였으며, 일부 구간에서는 이론식으로 계산한 분산계수와 근사한 값이 나타났다. 이는 사주가 매우 발달하고 만곡이 많은 실험구간의 특성상 Elder와 Fischer 식으로 계산한 값과 차이가 발생할 가능성이 높은 구간이기 때문인 것으로 판단된다. 또한 하폭에 대한 수심비가 커질수록 분산계수도 증가하고 평균유속에 대한 전단유속에 비에 비례하는 것으로 나타났다.

• Geophysics and Geophysical Exploration
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• v.3 no.2
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• pp.48-52
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• 2000

We have calculated and analyzed the electromagnetic responses of buried conductive pipes due to a horizontal magnetic dipole source on the pound using a three-dimensional (3-D) finite element method to provide useful guidelines for designing electromagnetic pipe locator and for field operation of the system. For single buried pipe, the horizontal component and the horizontal difference of the vertical component of magnetic field show peaks above the pipe. When comparing the width of response curves of both cases around the peak, horizontal difference of vertical component of magnetic field shows much narrower peak, 2 times narrower at a half of maximum amplitude, than that of horizontal component of magnetic field. Accordingly, we can pinpoint the horizontal location of pipe on the ground more accurately by measuring the horizontal difference of vertical component of magnetic fold. Moreover, it will have a merit in determining the depth of pipe, because the equation for depth estimation is defined just above the pipe. When there are two buried pipes separated by two meters with each other, the response of horizontal difference of vertical component of magnetic field has two separate peaks each of which is located above the pipe whereas horizontal magnetic field response has only one peak above the pipe just below the transmitter. Thus, when there exist more than a buried pipe, measuring the horizontal difference of vertical magnetic field can effectively detect not only the pipe under transmitter but also adjacent ones. The width of response curves also indicates higher resolving ability of horizontal difference of vertical component of magnetic field.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.128-133
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• 2020

In this study, an 1-dimensional positioning method using iterative linear regression for path loss expression is proposed. In the proposed method, received signal strengths (RSS) measured in several locations and distances between the measuring locat ions obtained by dead reckoning are used to derive a linear regression for the path loss from the transmitting beacon. In the proposed method, for the distance between the transmitting beacon and a target measuring location, several tentative values are assumed. For each tentative value, a linear regression is obtained. Among the linear regression expressions, the one closest to the known reference RSS value is selected and used to derive the distance to the target location. Test results show that the proposed method is more accurate than path loss model.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.635-645
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• 2015

The objective of this study is to examine the three-dimensional turbulent flows occurring in the meandering channel with presence of a groyne. A series of laboratory experiments are carried out in a meandering channel with trapezoidal cross sections. The channel is a 24.4 m long, 1.5 m wide, and the bottom slope in the longitudinal direction is 0.02. Two cases with and without the groyne are considered in the experiment. Three-dimensional velocity fields are measured using an acoustic Doppler velocimetry (ADV) at approximately sixty locations in each cross section. The measured velocity fields are averaged in time, and the time-averaged flow revealed that the mean velocity magnitude along the outer bank of the channel was reduced significantly and the direction of the primary flow was directed toward the center of the channel due to the presence of the groyne.

• Journal of Animal Environmental Science
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• v.17 no.2
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• pp.93-100
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• 2011

This study was conducted to verify the applicability of robot milking system through acquisition and analysis of model teat's position information using scanning range finder (SRF). Model teats, same size and shape as real teats, were designed to analyze the properties according to the material, distance error and angle error of the sensor. In addition, 2-dimensional distance information of each teats was obtained at same time with 4 teat models and the result were as follows. 1. In the case of the fingers on the experiment for selection of materials for teat model, the distance error was from 4.3 mm to 1.3 mm, average was 2.8 mm as a minimum record. In the case of rubber material, average distance error was 4.3 mm. So, this material was considered to be a most suitable model. 2. The distance error was maximum at 100 mm distance. The more distance increased, the less error increased up to 300 mm. Then the error increased after 300 mm and decreased again. 3. The maximum angle error of 10.1 mm was measured at $170^{\circ}$, in case of $70^{\circ}$ the error was 0.2 mm as a minimum value. There was no specific tendency to error of angle. 4. In the 2-dimensional location error for 4 teat models, distance error was 3.8 mm as minimum and 7.2 mm as maximum. The angle error was $1.2^{\circ}$ as maximum. All of errors were included within the accuracy of sensor, the robot milking system was considered to be applicable to measure the distance of teats due to the measuring velocity of SRF and the hole size of teat-cup.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.59-69
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• 2013

The numerical simulations were performed to analyze the advection-diffusion processes of dredging-induced turbidity plume using RMA2 and RMA4 models in Bunam reservoir, Seosan, Chungnam. Field survey was also performed to measure the turbidity using the multi water quality monitoring system (YSI6600EDS). In the field survey, the vertical and horizontal distributions of the turbidity were measured during the dredging operation in Bunam reservoir. RMA2 model was used to simulate the velocity distributions in both the whole domain and the 2nd part of Bunam reservoir. RMA4 model was also used to simulate the concentration distribution in only the 2nd part of Bunam reservoir, where the dredging work were conducted. The comparison of the simulation results with the field data for the advection-diffusion of the turbidity plume using the concentration ratio concepts shows that the numerical model can be applied to analyze the environmental impact of dredging works.

• Progress in Medical Physics
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• v.8 no.2
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• pp.77-85
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• 1997

Verification of patients setup was very important during radiotherapy. Therefore, we have developed an 1-dimensional on-line portal imaging system and measured the differential linearity of the system. Isooctane(2,2,4-TetraMethyl Pentane) was used as liquid ionization material. And the geometry of the system was designed which has 2mm position resolution and 20cm measurable range. And then the differential linearity of the system was 4.7％.

• Science of Emotion and Sensibility
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• v.26 no.2
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• pp.39-52
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• 2023

According to the core affect theory, affect consists of two independent dimensions of valence and arousal. Previous studies have found that various types of stimuli, such as pictures, videos, and music, are mapped onto the core affect space. However, the research on affect using gustatory stimuli has not been explored sufficiently. This study investigated whether the affects elicited by tastes could be mapped onto the core affect space. Stimuli were selected based on two factors (taste types and intensity). Participants were presented with each stimulus, evaluated the tastes, and rated their affective responses on taste and emotion scales. The data were analyzed using repeated-measures ANOVAs and multivariate analyses (multidimensional scaling and classification). The results of univariate analyses indicated that participants felt positive for sweet stimuli but negative for bitter and salty. Furthermore, participants reported high arousal with high intensity. Multidimensional scaling revealed that taste stimuli are also represented on the core affect dimensions. Specifically, it was confirmed that in the first dimension, sweetness was represented as a positive affect, while bitter and salty tastes were represented as a negative affect. In the second dimension, bitterness was represented as low arousal and sourness as high arousal. Classification analyses confirmed that the taste was identified consistently based on the affective responses within and across participants. This study showed that the taste stimuli in daily life are also located on core affect dimensions of valence and arousal.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1537-1543
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• 1999

In this paper, PSD(Position Sensitive Detector) sensor system that estimates position for moving objects in 2D plane is developed. PSD sensor is used to measure the position of an incidence light in real-time. To get the position of light source of moving target, a new parameter calibration algorithm and neural network technique are proposed and applied. Real-time position measurements of the mobile robot with light source is examined to validate the proposed method. It is shown that the proposed technique provides accurate position estimation of the moving object.