• Economic and Environmental Geology
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• v.36 no.5
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• pp.329-338
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• 2003

The purpose of this study is to identify the temporal and spatial variation of stable isotopic compositions of surface waters and shallow ground waters at a local watershed(100$Km^2$) near the Muju area. For oxygen and hydrogen isotope analysis, water samples were collected from 19-22 sites during August, October 2001, through April 2002. Seasonal variation in the isotopic compositions of surface waters was clearly shown. However, the degree of such isotopic variation was highly attenuated in shallow ground waters because of mixing with preexisting ground waters. Isotope values of surface waters and ground waters were very similar in each season, indicating that precipitation/ground water/surface water interactions were very active and continuous in the watershed. Stable isotopic ratios of surface waters in the study area were lighter than those of the downstream reach of Geum River on south, indicating “latitude effect”. Both “altitude effect” and “amount effect” were also shown in the stable isotopic ratios of surface waters in the study area as well as seasonal variation of stable isotopes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.73-78
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• 2011

The existent cutting insert have occupied most product of grinding style, because it has a problem of accuracy and manufacturing process. The product has a concept but development is difficult, because grinding and manufacturing by press are impossible. But by development and stabilization of a technology, preference of non-ground insert increases gradually. And then insert that grinding is impossible is developed availably as non-ground product by using developed equipment and software. In this paper reports some experimental results on the machining performance of non-ground Cutting inserts. Three kinds of Cutting inserts were manufactured without using grinding process. Machining experiments were carried out to compare the machining performance of non-ground inserts with that of ground ones. The experimental results indicate that the cutting forces and tool wear and surface roughnesses of machined surface of both ground and non-ground inserts are comparable.

• Geomechanics and Engineering
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• v.4 no.1
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• pp.1-18
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• 2012

The spatial variation of ground motion in Kolkata Metropolitan District (KMD) has been estimated by generating synthetic ground motion considering the point source model coupled with site response analysis. The most vulnerable source was identified from regional seismotectonic map for an area of about 350 km radius around Kolkata. The rock level acceleration time histories at 121 borehole locations in Kolkata for the vulnerable source, Eocene Hinge Zone, due to maximum credible earthquake (MCE) moment magnitude 6.2 were generated by synthetic ground motion model. Soil investigation data of 121 boreholes were collected from the report of Soil Data Bank Project, Jadavpur University, Kolkata. Surface level ground motion parameters were determined using SHAKE2000 software. The results are presented in the form of peak ground acceleration (PGA) at rock level and ground surface, amplification factor, and the response spectra at the ground surface for frequency 1.5 Hz, 3 Hz, 5 Hz and 10 Hz and 5% damping ratio. Site response study shows higher PGA in comparison with rock level acceleration. Maximum amplification in some portion in KMD area is found to be as high as 3.0 times compared to rock level.

• Journal of the Korean Geosynthetics Society
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• v.13 no.1
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• pp.23-31
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• 2014

In this study, the method to measure effectively the ground surface displacement of slope was proposed using the Laser Distance Measurer (LDM). Applying the proposed technique is more simple and easier than the complicated and high-priced instrument to measure the ground surface displacement. LDM is an instrument that the red laser aimed at the target and then the reflected laser used for calculating the distance. The advantages of LDM are easy operating method, high measurement precision and lower in price. To check the feasibility, the proposed method applied to the real site that the ground surface displacement of slope was occurred continuously. The ground surface displacements were occurred in various points of the natural and cut slopes located at the lower part of coal mine waste heap due to the load of waste heap. To measure directly the ground surface displacement in this site, 6 measurement sections and 26 measurement points were selected. As the result of the displacement measured by the proposed technique within a certain period time, the accumulative ground surface displacement could be measured as well as the velocity of displacement could be estimated. Also, the progress direction of ground surface displacement can be confirmed and predicted through the analysis of all measured result.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.2
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• pp.36-46
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• 1987

An optical technique using laser for non-contact measurement of surface roughness and form accuracy of ground surfaces is presented. It is found that, when a ground surface is illuminated by a beam of laser light, the roughness height and slope distribution has significant influence on the pattern of reflection and it maintains an unique Gaussian distribution relationship with the surface roughness. The principle idea of the optical measurement system is therefore monitor the radiation, and then calibrate it in process against surface roughness by means of necessary digital data processing. On the other hand, measuring the form accuracy of a ground surface is accomplished by using a triangular method, which is based on observing the movement of an image of a spot of light projected onto the surface. The image is focused, through a series of lenses for magnification, on a photodetector array lf line configur- ation. Then the relative movement of image and consequently the form accuracy of the surface can be obtained through appropriate calibration procedures. Experimental test showed that the optical roughness measurement technique suggested in this work is very efficient for most industrial applications being capable of monitoring the roughness heights ranging 0.1 to 0.6 .$\mu$m CLA values. And form accuracy can be measured in process with a resolution of 10 .$\mu$m.

• Proceedings of the KSRS Conference
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• v.2
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• pp.655-659
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• 2006

Surface Solar Insolation is important for vegetation productivity, hydrology, crop growth, etc. In this study, Surface Solar Insolation is estimated using Multi-functional Transport Satellite (MTSAT-1R) in clear and cloudy conditions. For the Cloudy sky cases, the surface solar insolation is estimated by taking into account the cloud transmittance and multiple scattering between cloud and surface. This model integrated Kawamura's model and SMAC code computes surface solar insolation with a 5km ${\times}$ 5km spatial resolution in hourly basis. The daily value is derived from the available hourly Surface Solar Insolation, independently for every pixel. To validation, this study uses ground truth data recorded from the pyranometer installed by the Korea Meteorological Agency (KMA). The validation of estimated value is performed through a match-up with ground truth. Various match-up with ground truth. Various match-up window sizes are tested with 3${\times}$3, 5${\times}$5, 7${\times}$7, 9${\times}$9, 10${\times}$10, 11${\times}$11, 13${\times}$13 pixels to define the spatial representativity of pyranometer measurement, and to consider drifting clouds from adjacent pixels across the ground station during the averaging interval of 1 hour are taken into account.

• Korean Journal of Remote Sensing
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• v.22 no.5
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• pp.389-396
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• 2006

Surface Solar Insolation is important for vegetation productivity, hydrology, crop growth, etc. In this study, Surface Solar Insolation is estimated using Multi-functional Transport Satellite (MTSAT-1R) in clear and cloudy conditions. For the Cloudy sky cases, the surface solar insolation is estimated by taking into account the cloud transmittance and multiple scattering between cloud and surface. This model integrated Kawamura's model and SMAC code computes surface solar insolation with a $5\;km{\times}5\;km$ spatial resolution in hourly basis. The daily value is derived from the available hourly Surface Solar Insolation, independently for every pixel. To validation, this study uses ground truth data recorded from the pyranometer installed by the Korea Meteorological Agency (KMA). The validation of estimated value is performed through a match-up with ground truth. Various match-up with ground truth. Various match-up window sizes are tested with $3{\times}3,\;5{\times}5,\;7{\times}7,\;9{\times}9,\;10{\times}10,\;11{\times}11,\;13{\times}pixels to define the spatial representativity of pyranometer measurement, and to consider drifting clouds from adjacent pixels across the ground station during the averaging interval of 1 hour are taken into account.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.19-24
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• 1998

This paper aims to clarify the effects of grinding conditions on the ground surface and bending strength in surface grinding of various ferrites with diamond wheel. The main conclusions obtained were as follows. The surface roughness becomes better at lower wheel speed in the case of v/V=1$\times$10-3, and the condition of v/V=1$\times$10-4shows the best performance for the finish grinding. When the relative contact temperature becomes lower at a constant value of v/V, the ground surface exhibits lower roughness. The ground surface shows that the fracture process during grinding becomes more brittle at the higher value of v/V. The damage depth which affect the bending strength is below 10$\mu$m in the grinding condition of S=10㎣/mm.s with the diamond tool after dressing & truing, however, the depth increases with increasing removal rate(S). When the strength degradation due to grinding is larger, the removal depth for the recovery of strength requires a larger size.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.872-879
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• 2010

High rock-fill embankment is relatively flexible, which makes crest of embankment subject to excessive amplification in displacement due to earthquake loading. To overcome problems related with site response in high embankment, it is essential to evaluate shear-wave velocity profile of the embankment with improved accuracy and reliability. In this aspect, an experimental research was performed to answer how to perform surface-wave tests and to analyze measurements at an embankment site with a sloping ground surface. Unlike flat ground surface, sloping ground may hamper and slow down propagation of surface waves due to multiple reflections and refractions in embankment. To figure out this reasoning for the effect of multiple reflections and refractions due to sloping surface, surface wave tests were performed at a reservoir embankment of Chung-Song in North KyeongSang Province. Parameters involved in surface wave tests at non-flat surface, including source directionality, geometry-related constraint and frequency components in source function, were investigated using field measurements.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.121-129
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• 2002

The present paper describes a technique for installing an effective grounding grids, the major objective is forced on the experimental evaluation of the performance and characteristics with the arrangement and installation method for grounding grids consisting of the means to protect electric shock, electronics and computerized facilities against lightning, switching and ground fault surges. The study is oriented on two major areas: (1) the analysis of the ground surface potential gradient with the arrangement of grounding grids, (2) the control of the dangerous ground surface potential rise. The experiments wee carried out with the impulse currents as a function of the installation method or arrangement of grounding grids. An installation method of the inclined auxiliary grounding grid was proposed to overcome the drawbacks of equally spared grounding grids, i.e. an appropriate design concept far the installation of grounding grids was found out, It has been shown that the installation of the intwined auxiliary grounding grid can also result in a mere than 50% decrease in the maximum potential gradient on the ground surface and enhance the level of safety for persons and electronic equipments..