• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.137-147
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• 2022

Various geophysical exploration methods are used to determine the exact location of underground utilities, and many studies have been performed to improve the accuracy. This study analyzed the feasibility of exploring underground utilities through a new exploration method using cosmic ray muon. A prototype of a portable muon detector was manufactured by combining a scintillator and a silicon photomultiplier. Further, a calibration operation was performed on the muon count rate. The ground thickness of the ground model was measured using the muon detector prototype, where the value could be estimated with an error of about 3%, close to the actual. In addition, the theoretical basis for tomography analysis technology was analyzed to utilize the muon detector for exploring underground utilities, and a zenith angle correction method was presented. This study revealed that the technology of exploration using muon can analyze density with high resolution and will be used for exploring underground utilities.

• Journal of The Geomorphological Association of Korea
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• v.20 no.1
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• pp.45-56
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• 2013

Rock strength test on Dunduri cliff, Chungnam province, Korea, was performed using N-type Schmidt hammer and the depositional ages of the sediments overlying the cliff were derived using OSL dating method. The averaged R-values of the cliffs investigated here were lower than those observed from the shore platforms, but with larger scatter in the former. R-values were negatively correlated to cliff face retreat, implying that the irregularity of the coastal rock faces was closely related to lithology as the weaker rocks retreated much faster than the harder rocks. The overlying deposit of the cliff tends to be thicker at valleys and were poorly sorted with angular to subangular clasts in a matrix of silt. The OSL ages (ca. 70-77 ka) presented here were older than the previously reported exposure ages (ca. 7-30 ka) of the cliff face. Therefore, it is likely that the present sea cliff was developed by expansion of the platform which had been covered by slope deposits since the last interglacial and exposed again during the Holocene.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.51-64
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• 2009

A location tracking sensor such as GPS, INS, Radar, and optical equipments is used in tracking Maneuvering Targets with a multi-sensor, and such systems are used to track, detect, and control UAV, guided missile, and spaceship. Until now, Most of the studies related to tracking Maneuvering Targets are on fusing multiple Radars, or adding a supplementary sensor to INS and GPS. However, A study is required to change the degree of application in fusions since the system property and error property are different from sensors. In this paper, we perform the error analysis of the sensor properties by adding a ground radar to GPS and INS for improving the tracking performance by multi-sensor fusion, and suggest the tracking algorithm that improves the precision and stability by changing the sensor probability of each sensor according to the error. For evaluation, we extract the altitude values in a simulation for the trajectory of UAV and apply the suggested algorithm to carry out the performance analysis. In this study, we change the weight of the evaluated values according to the degree of error between the navigation information of each sensor to improve the precision of navigation information, and made it possible to have a strong tracking which is not affected by external purposed environmental change and disturbance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.10
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• pp.3371-3380
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• 1996

Low resolution spectral modeling of water vapor is carried out by applying the weighted-sum-of-gray-gases model (WSGGM) to a narrow band. For a given narrow band, focus is placed on proper modeling of gray gas absorption coefficients vs. temeprature relation used for any solution methods for the Radiative Transfer Equation(RTE). Comparison between the modeled emissivity and the "true" emissivity obtained from a high temperatue statistical narrow band parameters is made ofr the total spectrum as well as for a few typical narrow bands. Application of the model to nonuniform gas layers is also made. Low resolution spectral intensities at the boundary are obtained for uniform, parabolic and boundary layer type temeprature profiles using the obtained for uniform, parabolic and boundary layer type temperature profiles using the obtained WSGGM's with 9 gray gases. The results are compared with the narrow band spectral intensities as obtained by a narrow band model-based code with the Curtis-Godson approximation. Good agreement is found between them. Local heat source strength and total wall heat flux are also compared for the cases of Kim et al, which again gives promising agreement.

• Journal of the Korean association of regional geographers
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• v.18 no.3
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• pp.253-267
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• 2012

The study looked into the type and characteristics of debris landforms in Mt. Mudeung. By focusing on the representative area, we aimed to categorize the debris landforms based on the morphologic and genetic characteristcis. The types of debris areas in Mt. Mudeung can be divided into the exposed debris type, mixed type of matrix, and the boulder-hidden type. Supply of block in the debris slope area displays different features depending on types of rocks. For the stony slopes of andesite, the block must be moved from the columnar joint or cliff in the upper part. The andesite debris slopes display dominant edge shape while displaying no round shape. The granite stony slopes display dominant round shape and the present exposed slope was assumed to be formed as the core stone which was deep weathered moved along slope during the periglacial era and the matrix was removed after post-glacial era. The movements of blocks are assumed to be caused by solifluction process. The joint area where granite and andesite areas meet, granite is located beneath andesite area, and this implies that blocks were actively freezing and creeping by solifluction and freezing and thawing at that time. It can be assumes that the granite matrix formed plain slope and then andesite boulder covered up the slope. Currently, the blocks in the stony slopes of Mt. Mudeung shows almost no mobility and the stony slopes created under periglacial climate can be considered to be fossil landform.