• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.5
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• pp.389-397
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• 2006

The purpose of the present paper is to offer an analysis of LiDAR data processing and three dimensional terrain for Geographic Information System (CIS) applications. Generally, LiDAR survey is the method which obtains quantitative and qualitative information of the terrain using airborne laser scanning (ALS). We will get a most topographic data at a Triangular Irregular Network (TIN), Digital Surface Model (DSM) and Digital Elevation Model (DEM) using LiDAR data. We examined many factors such as visibility, hillshade, aspect and slope using DEM and DSM. The analyzing results obtained from each item are thought to be regarded as leading factors in the terrain analysis. It is to be hoped that LiDAR survey will contribute a new approach to the terrain analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.107-113
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• 1995

To investigate the behavior of platic deformation inaxisymmetric hot extrusion through square dies, the physical modelling with the plasticine as a model material is carried out at the room temperature. Some mechanical properties of the model material are determined by compression and ring compression tests. Visioplasticity method using experimetal grid distortion is introduced to anlayze the plastic flow, strain rate and strain distribution.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2243-2244
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• 2008

In this paper, XLPE cable underneath a bridge is modelled using EMTP/ATPDraw. Bridge section is also modelled by mutually coupled parallel conductor with XLPE cable. This paper is analysed the overvoltge by structure change of bridge section when the lightning occurs on the system.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.71-91
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• 2018

In recent years, application of UAV(Unmanned Aerial Vehicle) to seed sowing and pest control has been actively carried out in the field of agriculture. In this study, UAS(Unmanned Aerial System) is constructed by combining image sensor of various wavelength band and SfM((Structure from Motion) based image analysis technique in UAV. Utilization of UAS based vegetation survey was investigated and the applicability of precision farming was examined. For this purposes, a UAS consisting of a combination of a VIS_RGB(Visible Red, Green, and Blue) image sensor, a modified BG_NIR(Blue Green_Near Infrared Red) image sensor, and a TIR(Thermal Infrared Red) sensor with a wide bandwidth of $7.5{\mu}m$ to $13.5{\mu}m$ was constructed for a low cost UAV. In addition, a total of ten vegetation indices were selected to investigate the chlorophyll, nitrogen and water contents of plants with visible, near infrared, and infrared wavelength's image sensors. The images of each wavelength band for the test area were analyzed and the correlation between the distribution of vegetation index and the vegetation index were compared with status of the previously surveyed vegetation and ground cover. The ability to perform vegetation state detection using images obtained by mounting multiple image sensors on low cost UAV was investigated. As the utility of UAS equipped with VIS_RGB, BG_NIR and TIR image sensors on the low cost UAV has proven to be more economical and efficient than previous vegetation survey methods that depend on satellites and aerial images, is expected to be used in areas such as precision agriculture, water and forest research.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.4
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• pp.42-55
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• 2013

The purpose of this study is to figure out the place characteristics of preferable city tourist attractions through the contents analysis of non-academic literatures such as tourist guidebooks and web materials. The most preferable Seoul tourist attractions were selected by their frequency in literatures including Namsan and Hangang as 'natural' places, Dugsu Palace and Gyungbok Palace as 'historical' places, Itaewon and Daehak-ro as 'lively-cultural' places that were classified by their relativistic character. The main findings of the research are as follows. The essential place characteristics of tourist attractions were synthesized in urban, regional and place scale respectively. While 'contrast' was found to be the most distinguished character of the tourist attractions in the urban context, 'connectivity' was found to be the most distinguished character of the tourist attractions in the regional context. In addition, both 'visibility' and 'experience' were found to be the most distinguished characters of the tourist attractions in the place context. The characteristics of these places seem to be the universal fascination factors of city tourist attractions currently recognized by ordinary citizens. We expect to further strengthen the city identity and the city tourism effect by adopting those research results systematically to the urban environment. Therefore, it is needed to vitalize the urban tourist attractions that we make them to be more 'contrasting' with urban areas surrounding them, more 'connective' with vicinity areas and more 'visibly fascinating' and 'experienced actively and meaningfully' in each place of tourist attractions.

• Journal of Korean Society of Steel Construction
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• v.29 no.3
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• pp.193-204
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• 2017

Fatigue strength of temporary steels and painted structural steels corroded under outdoor atmospheric environments is not clear. In this study, fatigue tests were carried out on steel plates which were cut off from 7-year-old temporary structural member under subway construction environment and from 75-year-old Yeongdo bridge member under marine atmospheric environment. After removing corrosion production on the steel surface, 3-dimensional surface geometry of the corroded steel was measured at intervals of $1.0{\times}1.0mm$, and corrosion characteristics such as minimum, maximum and mean values of residual thicknesses were calculated. From the fatigue test and FEM analysis results, the relationship between corrosion characteristics and fatigue behavior was presented, and change in fatigue strength of the unpainted and painted steels corroded in outdoor environments was also presented.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.225-234
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• 2012

OSS(Open source software) pursues the freedom to have access to open source and offers several advantages, over the proprietary software, to enterprises. Based upon Rogers(1995)' innovation-diffusion process, we assume that attributes of innovations includes five characteristics of innovations: relative advantage, compatibility, complexity, trialability, and observability, and that firms' perceptions of these characteristics predict the rate of adoption of OSS. To test this hypothesis, we presents a survey result from 201 companies and institutions concerning the use of OSS. Statistical analysis shows that adoption is highly correlated with each of those characteristics of innovations, but the regression analysis indicates that only compatibility and observability have effects on the adoption of OSS. This implies that intrinsic value of OSS is important, but unless the appropriate service package for improving IT environment is provided, it is not easy to change the perspective of corporate customers more favorable toward OSS use. As a conclusion, the academic and practical implications are also discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.688-697
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• 2008

In this paper, an analysis method for indoor optical wireless channel properties based on photon model is presented for characterization of communication environment. In contrast to radio waves, optical waves have very short wave-lengths and very high frequencies, so that material properties become important. Channel models including diffuse reflections and absorption effects due to material surface textures make conventional electromagnetic wave analysis methods based on ray tracing consume enormous time. To overcome these problems, an analysis method using photon model is presented that approximates light intensity by a density of photons. The photon model ensures that simulation time is within a predictable limit.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.822-827
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• 2003

Topological maps have drawn more attention recently because they are compact, provide natural interfaces, and are applicable to path planning easily. To build a topological map incrementally, Voronoi diagram was used by many researchers. The Voronoi diagram, however, has difficulty in applying to arbitrarily shaped objects and needs long computation time. In this paper, we present a new method for global topological map from the local topological maps incrementally. The local topological maps are created through a thinning algorithm from a local grid map, which is built based on the sensor information at the current robot position. A thinning method requires simpler computation than the Voronoi diagram. Localization based on the topological map is usually difficult, but additional nodes created by the thinning method can improve localization performance. A series of experiments have been conducted using a two-wheeled mobile robot equipped with a laser scanner. It is shown that the proposed scheme can create satisfactory topological maps.

• Korean Journal of Optics and Photonics
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• v.12 no.5
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• pp.362-370
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• 2001

We prove that 3-D profile mapping using white light interferometry has systematic errors caused by aberrations of the optimal system. The tilt of an object invokes an offset between the object and the reference ray, which eventually makes the aberration cancel incompletely. The fringe peak of a white light interferogram is mainly affected by the aberration effect while the envelope peak remains stable. By the difference between the two peaks, it is easily confirmed how much the error existed in the fringe peak. Experimental results prove that the error caused by aberration is varied by object tilt, microscope NA, optics alignment within the range of $\pm$50nm.