• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.486-488
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• 2007

The Grid Reference System, which was firstly used in SPOT series, has been successfully adapted in KOMPSAT-1 and KOMPSAT-2 program, which identifies the geographical location to make image collection plans and manage the database of satellite images. Each Grid Reference System for KOMPSAT-1 and KOMPSAT-2 was designed based on system parameters related to each KOMPSAT-1 and KOMPSAT-2 and this fact leads to the need for the design of the Grid Reference System for KOMPSAT-3 (KGRS-3, hereafter), which reflects system parameters for KOMPSAT-3. The (K, J) coordinate system has been defined as the Grid Reference System for KOMPSAT-3 using heritages from KOMPSAT-1 and KOMPSAT-2 programs. The numbering of K begins with the prime meridian of K = 1 with running eastward on earth increasingly, and the numbering of J uses a value of J = 1000 at all points on the equator and begin with running northward increasingly. The Grid Reference System for KOMPSAT-3 is to be implemented in Ground Segment of KOMPSAT-3 system.

• International Journal of Safety
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• 제9권2호
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• pp.1-5
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• 2010

In order to analyze the potential rise of ground surface of grounding grid installed in buildings, the grounding simulator has been designed and fabricated as substantial and economical measures. This paper describes the study of touch and step voltages with grounding grid where earth leakage current is injected. To assess risk voltage of grounding grid, the grounding simulator and CDEGS program were used to obtain measured data and theoretical results of this study. The grounding simulator was composed of an electrolytic tank, AC power supply, a movable potentiometer, and test grounding electrodes. The potential rise was measured by grounding simulator, and the touch and step voltages were computed by CDEGS program. As a consequence, the touch voltage and step voltage above the grounding grid were very low, but were significantly increased near the edge of grounding grid.

• 한국지반신소재학회논문집
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• 제19권3호
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• pp.35-44
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• 2020

본 연구에서는 연약지반에 설치된 DCM 개량체의 개량효과를 개량형식에 따라 정량적으로 비교하기 위하여 일련의 실내모형 실험을 수행하였다. 즉, 무보강 및 3종류의 DCM 개량체 형식에 대한 상재하중 재하에 따른 지반 거동을 재현하고, 지반의 침하량 및 측방변위량을 분석함으로써 DCM 개량형식에 따른 연약지반의 거동을 평가하였다. 먼저, 모형지반에 대한 성토하중 재하시험 결과 무보강의 경우에는 작은 하중 증가에도 침하가 급격히 발생한 반면에, DCM 개량체가 적용된 경우에는 상대적으로 적은 침하가 발생하였다. 그리고 상재하중 증가에 따른 지반의 측방유동 거동을 분석한 결과, 무보강의 경우에는 작은 하중 증가에도 불구하고 측방변위가 크게 발생되었다. 그러나 DCM 개량체가 적용된 경우에는 상대적으로 적은 측방유동이 발생되었으며, 동일한 하중조건에 대한 측방유동 발생량의 크기는 말뚝식, 벽식, 격자식의 순으로 나타남을 확인하였다. 따라서 격자식 DCM 개량체가 적용된 경우가 측방유동에 대하여 우수한 지반개량효과를 나타낸 것으로 평가되었다.

• 대한원격탐사학회지
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• 제40권3호
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• pp.269-274
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• 2024

High-quality precipitation data are crucial for various industries, including disaster prevention. In South Korea, long-term high-quality data are collected through numerous ground observation stations. However, data between these stations are reprocessed into a grid format using interpolation methods, which may not perfectly match actual precipitation. A prime example of real-time observational grid data globally is the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (GPM IMERG) from National Aeronautics and Space Administration (NASA), while in South Korea, ground radar data are more commonly used. GPM and ground radar data exhibit distinct differences due to their respective processing methods. This study aims to analyze the characteristics of GPM and Constant Altitude Plan Position Indicator(CAPPI),representative real-time grid data, by comparing them with ground-observed precipitation data. The study period spans from 2021 to 2022, focusing on hourly data from Automated Synoptic Observing System (ASOS) sites in South Korea. The GPM data tend to underestimate precipitation compared to ASOS data, while CAPPI shows errors in estimating low precipitation amounts. Through this comparative analysis, the study anticipates identifying key considerations for utilizing these data in various applied fields, such as recalculating design rainfall, thereby aiding researchers in improving prediction accuracy by using appropriate data.

• 전기학회논문지P
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• 제60권3호
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• pp.120-125
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• 2011

When we design the grounding grid, dangerous voltage ANSI/IEEE Std. 80 method has been commonly used in the domestic area. However, the suitability of the ground rules for the design environment available. However, the suitability of the ground rules for the design environment available. In this paper, sticks according to the electrode conductor in combination with the mesh in order to design the ground by the IEEE Std.80 was designed. So in this paper, we examined of IEEE Std. 80 touch voltage method marginal utility and we induced for those problems by comparison between IEEE Std. 80 touch voltage value and simulation experimentation value. Furthermore, this paper presents a new design grounding system method that complements the IEEE Std. 80 method.

• 전기학회논문지P
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• 제62권3호
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• pp.139-144
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• 2013

In Korea, where most of the sites are narrow in space and their earth resistivity is relatively high, the spaces between grounding conductors are likely to be designed narrow in order to lower ground resistance and dangerous voltage below to the permitted safety values. In addition, ground nets are in the shape of square or rectangle depending on the location and size of the facilities and ground contact area, and inner conductors are laid out in grids like the pattern of nets. Nevertheless, with the existing designs, the marginal voltage for safety gets higher as the area is extended further outside, in comparison with that of inner mesh grounding, thus causing much difficulty maintaining them equipotential, and there exist limits in the burial, grounding grid design considering the dangerous voltage of muti-layered model in the constrained sites, was studied.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권3호
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• pp.162-167
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• 2004

The scale model grounding systems to study the behavior of grounding system in uniform soils have been designed and fabricated. Constructional details and instrumentation have been discussed. To verify the accuracy of the results obtained from the experimental tests, they have been compared with computer calculation results. Also, in order to assess the effectiveness of bonding two grounding systems, grounding grid conductors which were downsized as a scale factor of 100:1 were analyzed by using the scale model method. A profile of GPR(Grounding Potential Rise) of each case was measured. The scale model grounding system presented in this paper can be valuable tool to analyze the ground potential profile and ground resistance of practical grounding system.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1807-1813
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• 2018

In this paper, the fault line selection and location problems of single line-to-ground (SLG) fault in distribution network are addressed. Firstly, the adaptive filtering property for empirical mode decomposition is formulated. Then in view of the different characteristics showed by the intrinsic mode functions(IMF) under different fault inception angles obtained by empirical mode decomposition, the sign of peak value about the low-frequency IMF and the capacitance transient energy is chosen as the fault line selection criteria according to the different proportion occupied by the low-frequency components. Finally, the fault location is determined based upon the comparison result with adjacent fault passage indicators' (FPI) waveform on the strength of the interaction between the distribution terminal unit(DTU) and the FPI. Moreover, the logic nodes regarding to fault line selection and location are newly expanded according to IEC61850, which also provides reference to acquaint the DTU or FPI's function and monitoring. The simulation results validate the effectiveness of the proposed fault line selection and location methods.

• 한국항공우주학회지
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• 제35권8호
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• pp.670-676
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• 2007

A comparative study on ground boundary conditions for the airfoil in ground effect has been carried out. The objective of the present study is to clarify effects of the ground boundary conditions so that it will be helpful to analyse results of wind tunnel tests using the fixed ground board or the image method. A low Mach number preconditioned Navier-Stokes solver using the overlap grid method has been applied. It has been turned out that results with the symmetric boundary condition are almost the same to those with the moving boundary condition. Results with the fixed ground boundary show discrepancy to those with the moving boundary condition when flow separation on the ground board takes place.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.299-306
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• 2001

Crushed Stone Pile(CSP) is one of the ground improvement methods available to loose sand and clayey ground by forming compacted CSP in the weak soil layer. The effects of this method are enhancement of ground bearing capacity, reduction of settlement and prevention of lateral ground movement in cohesive layer, reduction of liquefaction potential in sandy ground. This study performs model tests in 1.0m${\times}$1.0m${\times}$1.0m and 1.5m${\times}$1.5m${\times}$l.2m model tank to observe bearing capacity of CSP treated ground. The area replacement ratio of CSP composite ground varies 20%, 30% and 40% with square grid pattern. After the composite ground was consolidated under pressure of 0.5kg/$\textrm{cm}^2$ and 1.0kg/$\textrm{cm}^2$, load tests were carried out. The results show that ultimate bearing capacity increases with area replacement ratio and the preconsolidation pressure of ground.