• Tunnel and Underground Space
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• v.31 no.1
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• pp.10-24
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• 2021

Rock mass classification for construction of underground facilities is essential to secure their stabilities. Therefore, the reliable values for rock mass classification from the precise information on rock discontinuities are most important factors, because rock mass discontinuities can affect exclusively on the physical and mechanical properties of rock mass. The conventional classification operation for rock mass has been usually performed by hand mapping. However, there have been many issues for its precision and reliability; for instance, in large-scale survey area for regional geological survey, or rock mass classification operation by non-professional engineers. For these reasons, automated rock mass classification using LiDAR becomes popular for obtaining the quick and precise information. But there are several suggested algorithms for analyzing the rock mass discontinuities from point cloud data by LiDAR scanning, and it is known that the different algorithm gives usually different solution. Also, it is not simple to obtain the exact same value to hand mapping. In this paper, several discontinuity extract algorithms have been explained, and their processes for extracting rock mass discontinuities have been simulated for real rock bench. The application process for several algorithms is anticipated to be a good reference for future researches on extracting rock mass discontinuities from digital point cloud data by laser scanner, such as LiDAR.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.1-15
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• 2013

Great loss of life and property has been occurred by the severe flood globally. In Korea, a flood inundation map is used as one of the non-structural measures for reducing flood damage, and various inundation models have been studied for flood inundation analysis. This study applies LiDAR data and LISFLOOD model for flood inundation analysis and discusses the the modeling results from levee breaching scenarios for evaluating the applicability of the model to stream inundation modeling. In the results of LISFLOOD modeling, maximum inundation area was similar to the inundation map by HEC-RAS model just less than 4%. The inundation area by each levee breaching scenario showed the difference from 0.2% to 6.5%. Inundation processes were different each other according to the position of levee breach point, and maximum inundation area and depth were changed by the flow direction of stream and flood plain. This study shows that LISFLOOD model can be applied properly to stream inundation analysis using various inundation scenarios.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.1-15
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• 2017

Recently terrorism targets unspecified masses and causes massive destruction, which is so-called Super Terrorism. Many countries have tried hard to protect their citizens with various preparation and safety net. With inexpensive and advanced technologies of sensors, the surveillance systems have been paid attention, but few studies associated with the classification of the pedestrians' trajectories and the difference among themselves have attempted. Therefore, we collected individual trajectories at Samseoung Station using an analytical solution (system) of pedestrian trajectory by LiDAR sensor. Based on the collected trajectory data, a comprehensive framework of classifying the types of pedestrians' trajectories has been developed with data normalization and "trajectory association rule-based algorithm." As a result, trajectories with low similarity within the very same cluster is possibly detected.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.645-653
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• 2021

Biopolymer is a general concept for high molecular compounds produced by living organisms. Among them, the xanthan and β-glucan, which are organic polymer mixture produced by micro-organisms, are mainly used to increase the viscosity of a substance. And diluting in water and mixing with sand or clay can increase compressive strength and shear strength. In this study, mixed soil prepared by mixing soil with xanthan and beta-glucan based biopolymers specially developed for the purpose of increasing soil strength was applied to the river bank revetment, and changes during winter were measured using ground LiDAR. As a result of analyzing winter changes in major sections using three-dimensional point cloud data obtained through ground LiDAR, there were no changes to the extent that it was difficult to confirm with the naked eye in the two sections coated with biopolymer blended soil. However, soil loss due to Rill erosion was confirmed in the natural embankment section where biopolymer blended soil was not used.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.431-440
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• 2005

Location, height and clear-length of individual tree can be measured directly by LiDAR Remote Sensing, and dbh(diameter at breast height) can be estimated indirectly by tree height measured by LiDAR. In addition, stand volume and stand biomass are computed from estimated growth factors. In this study, each estimated growth factor was compared to the field measurements to validate accuracy. The coefficient of determination of total tree heights was 0.66 for total trees, 0.68 for Pinus koraiensis, 0.66 for Larix leptolepis and 0.60 for Quercus spp. The coefficient of determination of clear-length was 0.79 for total trees, 0.73 for Pinus koraiensis, 0.79 for Larix leptolepis, 0.68 for Quercus spp. The coefficient of determination of dbh predicted was 0.73 for Pinus koraiensis, 0.73 for Larix leptolepis and 0.85 for Quercus spp. Moreover The coefficient of determination of basal area was 0.82 for Pinus koraiensis, 0.92 for Larix leptolepis and 0.95 for Quercus spp. Biomass per ha computed by growth factor using LiDAR was 40,306 dm/ha for Pinus koraiensis, 94,150 tdm/ha for Larix leptolepis and 94,481 tdm/ha for Quercus spp. by species.

• Journal of Cadastre & Land InformatiX
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• v.46 no.1
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• pp.23-35
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• 2016

Recently, along with the development of IT, the non-linearity and enlargement in the response to the combination of the building industry and IT have made a wide variety in outer shapes of the buildings. So buildings need a more accurate representation using visually superior three-dimensional space information. Therefore, the study models the shapes of the other buildings in accordance with the heights. Frist of all, we measured the buildings using a Terrestrial LiDAR. Second, we obtained a high-density point cloud date of the buildings. Through this data, we made the BIM model and compared the heights of each floor's outer information layers. And then identified the BIM data status using IFC standards formats. From this data, it proposes a new 3D cadastre and the alternative for the establishment of spatial information.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.61-66
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• 2009

This Paper describes a new program called DEM Generator need to process DEM from LiDAR data or digital map data. It is difficult to generate raster DEM from LiDAR mass point data sets and digital maps too large to fit into memory. The DEM Generator was designed to process DEM and shaded relief image of GeoTiff format in order of streaming meshes; I/O minimize tag, delaunay triangle, natural neighborhood or TIN, temporary files and grid. It is expected that we can be improved the precision of DEM and solved the time consuming problem of DEM generating of a wider area.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.54-70
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• 2023

Surveys and studies on cultural assets using LiDAR measurement are already active overseas. Recently, awareness of the advantages and availability of LiDAR measurement has increased in Korea, and cases of using it for surveys of cultural assets are gradually increasing. However, it is usually restricted to surveys of mountain fortresses and is not actively used for surveys of ancient tombs yet. Therefore, this study intends to emphasize the need to secure fundamental data from LiDAR measurement for the era from the Three Kingdoms to Unified Silla in which recovery, maintenance, etc., in addition to the actual surveys, are unfulfilled due to the sites being mainly distributed in mountainous areas. For this, LiDAR measurement was executed for the area of Jangsan Ancient Tombs and Chunghyo-dong Ancient Tombs in Seoak-dong, Gyeongju, to review the distribution and geographical conditions of ancient tombs. As a result, in the Jangsan Ancient Tombs, in which a precision archaeological (measurement) survey was already executed, detailed geographic information and distribution conditions could be additionally identified, which could not be known only with the layout indicated by the topographic map of the existing report. Also, in the Chunghyo-dong Ancient Tombs, in which an additional survey was not conducted after 10 tombs were found during the Japanese colonial period, the location of the ancient tombs initially excavated was accurately identified, and the status and additional information was acquired, such as on the conditions of ancient tombs not surveyed. Such information may also be used as fundamental data for the preservation and maintenance of future ancient tombs in addition to the survey and study of the ancient tombs themselves. LiDAR measurement is most effective for identifying the condition of ancient tombs in mountainous areas where observation is difficult or access is limited due to the forest zone. It may be executed before on-site surveys, such as archaeological surveys, to secure data with high availability as prior surveys or pre-surveys. Therefore, it is necessary to secure fundamental data from LiDAR measurement in future surveys of ancient tombs and to establish a survey and maintenance/utilization plan based on this. To establish survey/study and preservation/maintenance measures for ancient tombs located in mountainous areas, a precision archaeological survey is currently executed to draw up a distribution chart of ancient tombs. If LiDAR measurement data is secured before this and used, a more effective and accurate distribution chart can be drawn up, and the actual conditions can be identified. Also, most omissions or errors in information can be prevented in on-site surveys of large regions. Therefore, it is necessary to accumulate fundamental data by actively using LiDAR measurement in future surveys of ancient tombs.

• Korean Journal of Remote Sensing
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• v.28 no.5
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• pp.587-596
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• 2012

Verifying about eligibility of targeted site is necessary for execute Afforestation and Reforestation Clean Development Mechanism (A/R CDM) project which is followed by system of Kyoto protocol. The site have to be identified by which could not be in conformity with definition of forest. This study tried to propose a technology of classify for site selection of A/R CDM. We chose several parts of Yangpyeng as study area and applied LiDAR data and remotely sensed imagery for considering about tree height, degree of crown closure, and land area which 3 factors for identify forest. LiDAR data was used for offset the shortage of remotely sensed imagery that cannot perfectly determine the forest definition due to absence of 3-dimentional information, but can be obtained from LiDAR. Considering tree height, degree of crown closure, and land area simultaneously by moving window, classified fields to forest and non forest based on pixel size. As a result, 124.06 ha for suitable to doing plantation and approximately 357.02 ha are in negative. Technology that applied for analyzing will provide fundamental methodology not only site selection for A/R CDM, but will be utilized in other Kyoto protocol.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.13-18
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• 2019

The DEM(Digital Elevation Model) is a three-dimensional spatial information that stores the height of the terrain as a numerical value. This means the elevation of the terrain not including the vegetation and the artifacts. The DEM is used in various fields, such as 3D visualization of the terrain, slope, and incense analysis, and calculation of the quantity of construction work. Recently, many studies related to the construction of 3D geospatial information have been conducted, but research related to DEM generation is insufficient. Therefore, in this study, a DEM was constructed using a MMS (Mobile Mapping System), UAV image, and UAV LiDAR (Light Detection And Ranging), and the accuracy evaluation of each result was performed. As a result, the accuracy of the DEM generated by MMS and UAV LiDAR was within ± 4.1cm, and the accuracy of the DEM using the UAV image was ± 8.5cm. The characteristics of MMS, UAV image, and UAV LiDAR are presented through a comparison of data processing and results. The DEM construction using MMS and UAV can be applied to various fields, such as an analysis and visualization of the terrain, collection of basic data for construction work, and service using spatial information. Moreover, the efficiency of the related work can be improved greatly.