• 대한추나의학회지
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• 제4권1호
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• pp.141-153
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• 2003

Objectives : The purpose of this study is researching for correlation between Moire topography results and questionnaire which include obesity rate, height, weight, posture, pain aspect (low back pain, headache, fatigue, neck pain etc), studying posture, school attendance method, menarche. Methods : The authors practiced Moire topography and questionnaire for primary & middle school 24,419 students [male 12,843, female 11,576] in Jeonbuk, korea in 2002. After we distinguished students who had abnormal finding in Moire topography and statistically analysed the data. Results : According to this research, the abnormal finding in Moire topography results was 37.3% (9,105 students), and students needed X-ray re-examination were 3.9% (953 students). According to statistical analysis, male/female and primary/middle school students have no difference in deformity degree of the body surface examined by Moire. Height and weight have low correlation with deformity degree of the body surface examined by Moire and menarche, pain aspect have no correlation. But, school attendance method by bicycle and $90^{\circ}$upright sitting in study posture is the best way to decrease the deformity degree of the body surface examined by Moire. Conclusions : Following this research, throughout Moire topography could detect trunk asymmetry that couldn't be found existing X-ray examination, and school attendance by bicycle and $90^{\circ}$upright sitting in study posture is good for school students to prevent back deformity.

• 한국환경과학회지
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• 제26권10호
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• pp.1111-1124
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• 2017

This study aimed to understand the distribution of vegetation in the eastern and western sides of the Baekdudaegan (ridge) dividing the Odaesan National Park, as influenced by its topography and climate. The actual vegetation, topography and climate for each side were used in the overlay analysis. The results of the analysis of actual vegetation showed a high distribution rate of Quercus mongolica forest on both the eastern and western sides. On the eastern side, the distribution rate of Pinus densiflora forest and P. densiflora-Q. variabilis forest was high, while the western side had a high distribution rate of deciduous broad-leaved tree forest and Abies hollophylla forest. A clear trend was identified for vegetation distribution with respect to elevation but not with respect to slope or aspect. The results of micro-landform analysis showed that the P. densiflora forests in the ridge and slope and the deciduous broad-leaved tree forest in the valley were respectively distributed with a high ratio. In terms of climate, the eastern side revealed an oceanic climate, with a relatively high average annual temperature, while the western side was characterized by relatively high average annual humidity and average annual precipitation. The distribution rate of P. densiflora forest was found to be high on the eastern side of the mountain range.

• 대기
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• 제24권1호
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• pp.17-27
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• 2014

In this study, the observational environment for sunshine duration at Seoul and Daegu Automated Synoptic Observing Systems (ASOSs) was analyzed using a numerical model. In order to analyze the effects of topography and buildings on observational environment for sunshine duration, the model domains including the elevated building and mountainous areas around Seoul and Daegu ASOSs were considered. Three dimensional topography and buildings used as input data for the numerical model were constructed using a geographic information system (GIS) data. Solar azimuth and altitude angles calculated for the analysis period (one-week for each season in 2008) in this study were validated against those by Korea Astronomy and Space Science Institute (KASI). The starting and ending times of sunshine duration observed at ASOSs largely differed from the respective sunrise and sunset times simply calculated using solar angles and information of ASOSs' latitude and longitude, because uneven topography and elevated buildings around ASOSs cut off sunshine duration right after the sunrise and right before the sunset. The model produced the sunshine indices for Seoul and Daegu ASOSs with the time interval of one minute and the period of one week for each season and we compared the hourly averaged indices with those observed at the ASOSs. One week of which the cloudiness is lowest for each season is selected for analysis. Not only the adjacent buildings but also distant buildings and mountain cut off sunshine duration right after the sunrise and right before the sunset. The buildings and topography cutting off sunshine duration were found for each analyzing date. It was suggested that, in order to evaluate the observational environment for sunshine duration, we need to consider even the information of topography and/or building far away from ASOSs. This study also showed that the analyzing method considering the GIS data is very useful for evaluation of observational environment for sunshine duration.

• 한국해양공학회지
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• 제20권3호
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• pp.67-76
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• 2006

Three-dimensional information of submarine topography was acquired by assembling DGPS and Echo Sounder, which is mainly used in the marine survey. However, the features of submarine topography, derived according to mechanical data, were confirmed using human eyes. Because the dredging capacity using a submarine surveying data influences harbor public affairs, analysis and the process method of surveying data is a very special element in construction costs. In this study, information on submarine topography is acquired by assembling DGPS and Echo Sounder. Moreover, the dredging capacity in harbor public affairs has been analyzed by the interpolation method: inverse distance to a power, kriging, minimum curvature, nearest neighbor, and radial basis function. Also, utilization of DGPS and Echo Sounder method in calculation of the dredging capacity have been confirmed by comparing and analyzing the dredging capacity and the actual one, as per each interpolation. According to this comparison result, in the case of applying Radial basis function interpolation and Kriging, 3.94 % and 4.61 % of error rates have been shown, respectively. In the case of the study for application of the proper interpolation, as per characteristics of submarine topography, is preceded in calculation of the dredging capacity relevant to harbor public affairs, it is expected that more speedy and correct calculation for the dredging capacity can be made.

• Korean Journal of Geomatics
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• 제2권1호
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• pp.57-64
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• 2002

Measuring the depth of water is very important in ensuring the protection and safety of seaside. There are many difficulties in making the contour bathymetric map, and contour line due to the limitation of continuous measurement of water depth and collimation with the conventional measuring and positioning methods. But the real-time kinematic GPS (RTK GPS) positioning using a carrier phase enables us to decide a precise position without breaking a signal even under the condition of a moving environment. It is also possible to obtain an accurate depth of water in real time with a fathometer through the measuring of time delay between sending and receiving epochs. This research aims at investigation of accuracy potential of RTK GPS in combination with Echo Sounder(E/S) for the coastal mapping. Apart from this purpose, the accuracy of ambiguity resolution with the OTF(On the Fly) method was tested with respect to the initialization time. The result shows that the accuracy is better than 1cm with 5-minute initialization in the distance of 10km baseline. The seaside topography was measured by the RTK GPS only, on the other hand the seafloor topography was surveyed in combination of RTK GPS and E/S. Comparing to the volume of seaside measured by RTK GPS and digital topographical map, the difference of only 2 % was achieved. This indicates that the coastal mapping with RTK GPS is successfully conducted. In addition it is also demonstrated that the 3-dimensional perspective model resulted from the undersea topography measured by RTK GPS and E/S is very close to that from the digital map. Through this study, it was verified that RTK GPS is to be very useful method in the analysis of coastal morphology owing to its capability of getting the precise DTM for the using of harbor reclamation, dredging, and the estimation of soil movement in a river.

• 지구물리와물리탐사
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• 제20권3호
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• pp.163-175
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• 2017

육상 탄성파 탐사에서 불규칙한 지표 고도차와 천부 지층의 풍화대는 자료의 반사파 신호를 왜곡시킨다. 그러므로 일반적인 육상 탄성파 탐사 자료는 정적 보정(static correction)을 통해 이러한 왜곡을 보정해야 한다. 정적 보정을 하기 위해 천부 지층의 속도가 필요하며, 이 속도는 굴절법 탐사를 통해 구할 수 있다. 그러나 육상 탄성파 탐사자료는 탐사 현장에 대한 허가나 현장 여건 그리고 장비 보유 현황에 따라 제한된 형태로 취득되는 경우가 많다. 이러한 상황에서는 송수신기 배열이 제한되어 굴절법 탐사에 적합한 자료를 얻을 수 없기 때문에 반사법 자료로 굴절법 해석을 수행할 수 밖에 없다. 따라서 본 연구에서는 불규칙 지표 모델에서 제한된 송수신기 배열을 이용하여 얻은 반사법 자료로 굴절 주시 역산을 수행하고 결과의 신뢰성을 분석하였다. 불규칙한 지표와 평탄한 지표를 갖는 모델에 대한 역산 결과를 비교하여 지표 고도 차이가 역산 결과의 신뢰성에 약간의 영향을 주는 것을 확인하였다. 또한, 송신원 개수에 따른 역산을 통해 극히 적은 수의 송신원이 아니라면 역산 결과의 신뢰성에 크게 영향을 주지 않음을 보였다. 반면에 제한된 배열의 수신기를 사용할 경우에는 수신기 전개영역의 중첩된 부분에서 속도왜곡이 발생함을 관찰하였고, 속도왜곡이 발생하지 않기 위한 최소 중첩영역의 크기를 제안하였다. 마지막으로 현장 자료의 지형 조건과 송수신기 배열 정보를 이용하여 수치 모형 실험을 수행하였고, 신뢰성 분석 결과를 검증하였다. 신뢰성 분석 결과를 토대로 현장 자료 역산 결과에 신뢰할 수 있는 영역과 해석에 유의해야 할 영역을 구분하였다.

• 한국산림과학회지
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• 제108권1호
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• pp.50-58
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• 2019

우리나라에서 발생된 땅밀림지의 지형특성을 분석하여 땅밀림지에 대한 지형적인 기초자료를 제공하기 위하여 실시하였다. Aspect ratio가 1.00 미만인 땅밀림지는 전체 37개소 중 17개소(약 46.0 %)로 0.37 ~ 0.92의 범위를 나타내었다. 또한 Aspect ratio가 2.00 미만인 경우는 전체 37개소 중 36개소(약 97.0 %)이었다. 종단형상비가 1.00 미만인 땅밀림 지역은 총 37개소 중 15개소(약 41.0 %)이었으며, 1.00 이상인 땅밀림지는 22개소(약 59.0 %)이었다. 우리나라에서 발생한 전체 37개소의 땅밀림지 중 평면형지형은 말발굽형이 가장 많은 것으로 나타났다. 또한 미세지형은 철(凸)상대지상 지형이 가장 많은 것으로 나타났다. 땅밀림지역의 미세지형의 등고선 간격을 평균한 결과 29.4(9.5 ~ 83.2)m이었으며, 땅밀림지 내에서 미세지형을 제외한 땅밀림지 내의 평균등고선 간격은 24.3(14.4 ~ 59.4)m로 미세지형이 5.1(4.9 ~ 23.8)m 더 넓게 나타났다. 우리나라에서 발생한 땅밀림지 내에서 미세지형의 평균 등고선 간격과 미세지형을 제외한 평균 등고선 간격의 T-test 분석 결과 5 % 수준에서 유의한 것으로 나타났다.

• 대한기계학회논문집A
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• 제30권5호
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• pp.496-504
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• 2006

Wear of engine valves and seat inserts is a major factor affecting engine performance. In order to improve quality and life of valve assemblies, wear mechanism and 3-D surface topography should be analyzed according to operating conditions of the engine. After developing an engine simulator that generates valve speed up to 90Hz and temperature up to $900^{\circ}C$ as well as controls test load, wear experiments have been conducted for two different engine speeds as 10Hz and 25Hz. In order to observe the wear characteristics and monitor surface conditions of the valve assemblies, a cost-effective 3-D wear analysis system based on the shape from focus(SFF) and machine vision has been fabricated in this paper. 3-D surface topography of the valve assemblies has been analyzed to understand the wear behavior according to operating conditions of the engine. Consequently, wear volume of the valve assemblies is quantized by using the developed 3-D wear analysis system.

• Tribology and Lubricants
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• 제33권6호
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• pp.303-308
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• 2017

Most automobile tire companies have not yet considered the geometric information of a road at the design stage of a tire because the topographical characterization of a road surface is very difficult owing to its vastness and randomness. A road surface shows variable surface roughness values according to magnification, and thus, the contact force between the road and tire significantly fluctuates with respect to the scale. In this study, we make an attempt to define a representative value for surface topographical information at multi-scale levels. To represent surface topography, we use a statistical method called power spectral density (PSD). We use the fast Fourier transform (FFT) and PSD to analyze the height profiles of a random surface. The FFT and PSD of a surface help in obtaining a fractal dimension, which is a representative value of surface topography at all length scales. We develop three surfaces with different fractal dimensions. We use finite element analysis (FEA) to observe the contact forces between a tire and the road surfaces with three different fractal dimensions. The results from FEA reveal that an increase in the fractal dimension decreases the contact length between the tire and road surfaces. On the contrary, the average contact force increases. This result indicates that designing and manufacturing a tire considering the fractal dimension of a road makes safe driving possible, owing to the improvement in service life and braking performance of the tire.

• 한국측량학회지
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• 제20권3호
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• pp.303-311
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• 2002

최근에 GIS 기법을 이용하여 수문 분석에 필요한 지형 매개변수를 분석하는 연구가 활발히 진행되고 있는 실정이다. 지형 분석에 이용되는 DEM은 수치 지형도의 등고선 자료를 이용하여 효과적으로 구축될 수 있다. 따라서 DEM의 응용성이 여러 분야에서 점차 증가되고 있는 실정이다. 본 연구에서는 지형 매개변수 추출시 DEM 격자크기가 경사와 배수 유역에 어떤 영향을 주는지를 분석하고자 20m∼100m 격자 크기의 DEM이 평창강과 주방천 유역에 적용되었다. 본 연구에서는 DEM 격자크기에 따른 경사변화에 대한 회귀 방정식을 도출하였다. 그 결과 DEM 격자크기가 증가함에 따라 경사가 줄어들며, 배수 유역면적은 거의 변화하지 않는다는 것을 알 수 있었다.