• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.279-284
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• 2004

This paper presents on adjustment methods of the vendor-provided RPC(Rational Polynomial Coefficient) of GEO-level stereo images for the IKONOS satellite. RPC are adjusted with control points by the first-order polynomial and the block adjustment method in this study. As results, the maximum error of 3D ground coordinates by the adjusted RPC model did not exceed 4m. The block adjustment method is more stability than the first-order polynomial method.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.385-388
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• 2005

Through the regional lineament analysis in Korea peninsula, the statistical distribution of regional lineament is investigated. We also analyze the lineaments pattern using the fractal dimension. These results are the preliminary study for a understanding of the deep ground geological structure in Korea. For the investigations of the average block scale, we use the Dershowitz and Herda(1992)'s method. At result, the average spacing between the regional lineaments is about 10km.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6C
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• pp.255-263
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• 2010

This paper investigates the effects of tunnelling-induced ground movements on nearby structures, considering soil-structure interactions of different construction (ground loss) and soil characteristics. The response of four-story block structures, which are subjected to tunnelling-induced ground movements, has been investigated in different construction (ground loss) and soil conditions using numerical analysis. The structures for numerical analysis has been modelled using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The response of four-story block structures has been investigated with a ground movement magnitude and compared in terms of construction (ground loss) and soil conditions considering the magnitude of deformations and cracks in structures. In addition, the damage levels, which are possibly induced in structures, has been provided in terms of construction (ground loss) and soil conditions using the state of strain damage estimation criterion (Son and Cording, 2005). The results of this study will provide a background for better understandings for controlling and minimizing building damage on nearby structures due to tunnelling-induced ground movements.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1297-1302
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• 2004

In DC power distribution system for urban rail transits potential relay, 64P, is used to detect the ground faults. The problem with this 64P is that though it detects the ground fault it cannot identify the faulted region. Therefore the faulted region cannot be isolated properly. It could results in power loss of the trains on the healthy regions and the safety of the passengers in the trains could be affected adversely. A new ground fault protective relaying scheme that can identify the faulted region is presented in this paper. The new concept uses the current differential scheme and the permissive scheme to identify the faulted region correctly. A device with similar characteristic to the arrestor is adapted to use the current relay for the ground fault detection. The role of the device is to block the ground leakage current in normal operating condition and enable the ground fault current to flow in ground fault condition. The algorithm of the new relay and the effect of the newly adapted device in the new relaying scheme are discussed.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.5-10
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• 2012

Many electric poles in the softground have been collapsed due to external load. In this study, several tests were performed with variation of numbers and depths of anchor blocks to find effects of anchor blocks on stability of concrete electric poles through earth pressure and displacement analysis. 1.50m depth of anchor block seems appropriate among three kinds of depths. The 2.25m depth of anchor block makes larger displacement due to disturbance caused by excessive excavation. The deeper anchor block, the less earth pressure of passive zone, an active earth pressure gets larger. When two anchor blocks were installed, displacement at top pole decreased 43.8% and 55.6% at ground when 1 anchor block was installed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.55-59
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• 2013

In the oral and maxillofacial area, bone defects are created by various reasons and demand for bone grafts, while dental implant implantation has been increased consistently. To solve these problems, there has been development of autogenous tooth-bone graft material (AutoBT$^{(R)}$, Korea Tooth Bank Co., Korea), and we have collected ground reasons to substitute free autobone graft with this material in clinical use. This autogenous tooth-bone graft material is produced in powder type and block type. Block type is useful in esthetic reconstruction of the defect site and vertical and horizontal augmentation of alveolar bone because this type has high strength value, well maintained shape and is less absorbed. Therefore, the author of this study gained favorable result by grafting the block type autogenous tooth-bone graft material after dental implant implantation on the bone defects of the mandibular molar extraction site. Moreover, the author represents this case with literature review after confirming bone remodeling on the computed tomography image and by histological analysis.

• Journal of the Society of Disaster Information
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• v.13 no.2
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• pp.191-198
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• 2017

Lego block system forms a temporary pavement area using the assembled structure block in the road excavation work for the maintenance and installation of facilities. This system was developed for a safe passage of vehicles and pedestrians. A study on the fundamental performance of a lego block system was performed through material quality, sliding resistance and compression tests. And compaction performance of ground on the road was reviewed and evaluated through field tests. As a result, a lego block system for road recovery showed the excellent performance and compaction effect.

• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.16-25
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• 2007

A comparative study on the turbulent flaw simulation and the potential flaw analysis has been performed. A law Mach number preconditioned Navier-Stokes solver, using the multi-block grid method and a panel method based on the velocity potential, have been developed and validated by comparison to the experimental data. The present numerical analysis methods are applied to the ground effect problem around the NACA 4412 airfoil. It has been confirmed that the potential flaw analysis on the ground effect, using the image method, is consistent, to some degree, with the viscous calculations for high Reynolds number flows.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.4
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• pp.369-378
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• 2013

This paper presents a vision/LiDAR integrated navigation system that provides accurate relative navigation performance on a general ground surface, in GNSS-denied environments. The considered ground surface during flight is approximated as a piecewise continuous model, with flat and slope surface profiles. In its implementation, the presented system consists of a strapdown IMU, and an aided sensor block, consisting of a vision sensor and a LiDAR on a stabilized gimbal platform. Thus, two-dimensional optical flow vectors from the vision sensor, and range information from LiDAR to ground are used to overcome the performance limit of the tactical grade inertial navigation solution without GNSS signal. In filter realization, the INS error model is employed, with measurement vectors containing two-dimensional velocity errors, and one differenced altitude in the navigation frame. In computing the altitude difference, the ground slope angle is estimated in a novel way, through two bisectional LiDAR signals, with a practical assumption representing a general ground profile. Finally, the overall integrated system is implemented, based on the extended Kalman filter framework, and the performance is demonstrated through a simulation study, with an aircraft flight trajectory scenario.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.174-177
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• 2003

Kinds of most frequent faults happened on overhead distribution system are the single line-to-ground fault, the line-to-line fault and the two line-to-ground fault. Occasionally, the three line-to-ground fault and the disconnection of a wire are happened in severe conditions. In this study, the single line-to-ground fault, the line-to-line fault, two line-to-ground fault on three-phase four-wire overhead distribution system were experimentally simulated and characteristics of total leakage current of distribution arrester caused by these faults were investigated. Also, the changing aspect of total leakage current of distribution arrester caused by voltage variation was investigated. In a consequence, abnormal voltages caused by voltage variation, the line-to-line fault, the two line-to-ground fault have a little effect on total leakage current of ZnO arrester. But abnormal voltages caused by the single line-to-ground fault have an important effect on total leakage current of ZnO arrester.