• The Journal of Korea CHUNA Manual Medicine
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• v.4 no.1
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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.

• Journal of Environmental Science International
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• v.26 no.10
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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.

• Atmosphere
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• v.24 no.1
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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.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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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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• v.2 no.1
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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.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.163-175
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• 2017

In land seismic exploration, irregular surface topography and weathering layer in near surface distorts the reflected signals of data. Therefore, typical land seismic data should be compensated for this distortion by static correction. To perform the static correction, near-surface velocity is required, which can be obtained by seismic refraction survey. However, land seismic data is often acquired in a limited form of geometry depending on the equipment availability, accessibility condition, and permission for the survey site. In this situation, refraction analysis should be performed using reflection data because it is impossible to acquire refraction-oriented data due to limited source and receiver geometry. In this study, we aimed to analyze the reliability of the results obtained by refraction traveltime tomography when using reflection data with a limited number of sources and receivers from irregular surface topography. By comparing the inversion result from irregular topography with that from flat surface, we found that the surface topography affects the reliability of the inversion results to some degree. We also found that the number of sources has little effect on the inversion results unless the number of sources are very small. On the other hand, we observed that velocity distortion occurred in the overlapped part of receiver arrays when using a limited number of receivers, and therefore suggested the size of the least overlapping ratio to avoid the velocity distortion. Finally, we performed numerical tests for the model which simulates the surface topography and acquisition geometry of the survey region and verified the reliability analysis of inversion results. We identified reliable areas and suspicious area of the inverted velocity model by applying the analysis results to field data.

• Journal of Korean Society of Forest Science
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• v.108 no.1
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• pp.50-58
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• 2019

This study was carried out to analysis the landform characteristics of land creep areas in south Korea. Aspect ratio in 17 areas (approximately 46.0 %) among total land creep areas (37 areas) was ranged from 0.37 to 0.92. Also, aspect ratio in 36 areas (approximately 97.0 %) was less than 2. Longitudinal section form ratio of 15 areas (approximately 41.0 %) was less than 1.0, whereas 22 areas (approximately 59.0 %) were more than 1.0. Horseshoe hoof form in land creep areas were mostly appeared to flat land types, whereas convex terrain ground form was prevailed to micro-topography. Mean contour intervals were higher in micro-topography (mean 29.4 m, range 9.5 m ~ 83.2 m) than in except micro-topography (mean 24.3 m, range: 14.4 m ~ 59.4 m) in land creep areas. The contour intervals were slightly wider in micro-topography (mean 5.1 m, range: 4.9 m ~ 23.8 m) than in except micro-topography in land creep areas. The results indicate that contour intervals were significantly different (P < 0.05) between micro-topography and except micro-topography in land creep areas.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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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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• v.33 no.6
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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.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.303-311
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• 2002

Recently, the research that analyze topography parameters that need in hydrology analysis using GIS techniques is achieved. DEM that is used in topography analysis can be constructed effectively using contour data of digital map. Therefore, DEM's applicability is increasing gradually in several fields. In this study, DEM of 20∼l00m grid size was applied PYONGCHANG river and JUBANG river basin to analyze what effect DEM grid size causes about slope and drainage watershed at topography parameter extraction. This study drew a regression equation about slope change by DEM grid size. As a result, according as DEM grid size increases, slope decreases, and basin area could know that is not change almost.