• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.1
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• pp.31-52
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• 2024

Considering the significant relationship between a tree's branch structure and physiology, understanding the detailed branch structure is crucial for fields such as species classification, and 3D tree modelling. Recently, terrestrial laser scanning (TLS) and quantitative structure model (QSM) have enhanced the understanding of branch structures by capturing the radius, length, and branching angle of branches. Previous studies examining branch structure with TL S and QSM often relied on mean or median of branch structure parameters, such as the radius ratio and length ratio in parent-child relationships, as representative values. Additionally, these studies have typically focused on the relationship between trunk and the first order branches. This study aims to explore the distribution of branch structure parameters up to the third order in Aesculus hippocastanum, Ginkgo biloba, and Prunus yedoensis. The gamma distribution best represented the distributions of branch structure parameters, as evidenced by the average of Kolmogorov-Smirnov statistics (radius = 0.048; length = 0.061; angle = 0.050). Comparisons of the mode, mean, and median were conducted to determine the most representative measure indicating the central tendency of branch structure parameters. The estimated distributions showed differences between the mode and mean (average of normalized differences for radius ratio = 11.2%; length ratio = 17.0%; branching angle = 8.2%), and between the mode and median (radius ratio = 7.5%; length ratio = 11.5%; branching angle = 5.5%). Comparisons of the estimated distributions across branch orders and species were conducted, showing variations across branch orders and species. This study suggests that examining the estimated distribution of the branch structure parameter offers a more detailed description of branch structure, capturing the central tendencies of branch structure parameters. We also emphasize the importance of examining higher branch orders to gain a comprehensive understanding of branch structure, highlighting the differences across branch orders.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.488-497
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• 2013

The purpose of the study was to investigate the relationship between the degree of participation and flow for participants in ground, water, and air leisure sports-based tourism activities. A total of 437 participants' data was employed for the analyses (one-way ANOVA and multiple regression analysis) using SPSS Win 18.0 program. Main findings are as follows; First, there were differences in clear goals, transformation of time, loss of self-consciousness, challenge-skill balance, autotelic experience, unambiguous feedback, and sense of control out of flow dimensions based on types of leisure sports-based tourism activities. Second, participation period and frequence had positive effects on flow. Specifically, period had an influence on challenge-skill balance. clear goals: frequence had an effect on challenge-skill balance, transformation of time, clear goals, autotelic experience, unambiguous feedback, and sense of control: intensity had an influence on transformation of time and autotelic experience.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.357-365
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• 2009

RTLS(Real-Time location system) for Location tracking of personnel and equipment of a construction site is now in development, among these techniques the wireless LAN-based techniques are being considered. To introduce these techniques to the construction site, the 3-dimensional visibility analysis prior to the installation location of AP must be simulated. At this time, three-dimensional visibility analysis considering the propagation distance of RTLS signal of AP(Access Point) should be performed. In this research, two processing methods LOS boundary are tested to various grid size of gridded terrestrial LiDAR data, and the results were compared. In evaluations of visible area, the Scanline Fill-Method shows approximately 7.4% more visible area than the Shadow Clipping-Method, but the Shadow Clipping-Method shows stable results for the grid size. About the processing time, the Scanline Fill-Method is about 2 times faster compared to the Shadow Clipping-Method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.527-532
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• 2012

Terrestrial LiDAR emerges as a main mapping technology for indoor 3D cadastre, cultural heritage conservation and, building management in that it provides fast, accurate, and reliable 3D data. In this paper, a new 3D modeling method consisting of segmentation stage and outline extraction stage is proposed to develop indoor 3D model from the terrestrial LiDAR. In the segmentation process, RANSAC and a refinement grid is used to identify points that belong to identical planar planes. In the outline tracing process, a tracing grid and a data conversion method are used to extract outlines of indoor 3D models. However, despite of an improvement of productivity, the proposed approach requires an optimization process to adjust parameters such as a threshold of the RANSAC and sizes of the refinement and outline extraction grids. Furthermore, it is required to model curvilinear and rounded shape of the indoor structures.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.276-278
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• 2012

본 논문에서는 인공위성 탑재 컴퓨터의 가상머신에서 사용되는 C 언어와 유사한 언어를 번역하는 SpaceApp 토큰 컴파일러를 개발하였다. SpaceApp은 위성 제어를 위한 지상으로부터 업로드 가능한 프로그램으로, 이를 실행하기 위한 환경으로 자바가상머신과 유사한 SpaceApp 가상머신이 개발되었다. 이러한 가상머신에 필요한 컴파일러는 SpaceApp 언어를 번역할 수 있어야 하고, 실행 가능한 파일 형식으로 변환되어야 한다. 따라서 논문에서 개발한 컴파일러는 C 언어와 유사하게 SpaceApp 언어를 번역 가능하다. 그리고 인공위성 임무에 맞게 라이브러리를 지원하며, 가상머신에서 실행 가능한 파일 형식을 출력할 수 있도록 구현했다. 또한 통합 개발 환경으로 이클립스를 이용하여 편의성을 제공하도록 구현하였다.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.105-108
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• 2000

무선채널환경에서의 하향 방향 링크 상에서 페이딩 효과에 효과적으로 대처하고 고품질의 수신신호를 위하여 시간, 주파수 및 공간 영역 상에서의 여러 형태의 독립적인 다이버시티를 임의로 발생하기 위한 방안이 연구 되어왔다. 특히 3GPP 지상시스템에서 사용되는 개방형 전송 다이버시티 기법중 하나인 STTD( Space-Time Transmit Diversity)는 시공간 블록코드를 기반으로 하고 있으며, 본 논문에서는 이를 IMT-2000용 위성시스템의 순방향링크에 적용하여 이에 대한 결과를 고찰한다. 위성시스템의 순방향채널은 위성의 앙각에 의하여 라이시안 팩터 성분이 결정되며, 다수의 가시 위성군을 통하여 다이버시티효과를 발생시킴으로써 성능을 향상시킬 수 있다. 본 논문에서는 현재까지 상세한 규격작업이 이루어지고 있지 않은 IMT-2000용 위성시스템 상에서 두개의 가시위성을 통한 STTD 적용시 우수한 수신성능을 확인하였다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2009.04a
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• pp.115-117
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• 2009

Terrestrial Laser Scanner and Airborne Laser Scanning is one of the state of art surveying equipments. So This study deals with the combined use of mobile TLS(Terrestrial Laser Scanner) with ALS(Airborne Laser Scanning) to extract shoreline's topography information. These two systems have their own pros and cons. Mobile TLS can capture the facades of a low story building along the shoreline fast and quickly. Meanwhile, Due to viewpoint restrictions of ALS data collection, the amount of detail, which is available for the building facades is very limited. Therefore, it is recommended that the co-registration and geo-referencing methods of both two should be developed and the application of both system for shoreline mapping also should be investigated.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.525-528
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• 2008

3차원 레이저 스캐너는 고해상도 3차원 영상을 제공하고 레이저 빔을 현장이나 대상물에 발사하여 짧은 시간에 수백만점의 3차원좌표를 기록할 수 있는 최신 측량장비로서 다양한 응용분야에서 두각을 나타내고 있다. 본 연구에서는 3차원 레이저 스캐너를 이용하여 공사현장에서 슬래브 시공 시 철근배근 경계를 추출 철근배근 상태를 검측 하였다. 실험측량결과 지상라이다로 철근배근 경계를 신속하게 추출이 가능하였으며, 추출된 자료와 슬래브 도면과의 비교를 통하여 철근배근에 대한 검측이 가능하였다. 이에 따라 공사현장에서 레이저 스캐너를 이용하여 빠르고 정확한 시공검측과 자료 구축이 가능할 것으로 예상된다.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.177-186
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• 2021

For disaster management and mitigation of earthquakes in Korea Peninsula, active fault investigation has been conducted for the past 5 years. In particular, investigation of sediment-covered active faults integrates geomorphological analysis on airborne LiDAR data, surface geological survey, and geophysical exploration, and unearths subsurface active faults by trench survey. However, the fault traces revealed by trench surveys are only available for investigation during a limited time and restored to the previous condition. Thus, the geological data describing the fault trench sites remain as the qualitative data in terms of research articles and reports. To extend the limitations due to temporal nature of geological studies, we utilized a terrestrial LiDAR to produce 3D point clouds for the fault trench sites and restored them in a digital space. The terrestrial LiDAR scanning was conducted at two trench sites located near the Yangsan Fault and acquired amplitude and reflectance from the surveyed area as well as color information by combining photogrammetry with the LiDAR system. The scanned data were merged to form the 3D point clouds having the average geometric error of 0.003 m, which exhibited the sufficient accuracy to restore the details of the surveyed trench sites. However, we found more post-processing on the scanned data would be necessary because the amplitudes and reflectances of the point clouds varied depending on the scan positions and the colors of the trench surfaces were captured differently depending on the light exposures available at the time. Such point clouds are pretty large in size and visualized through a limited set of softwares, which limits data sharing among researchers. As an alternative, we suggested Potree, an open-source web-based platform, to visualize the point clouds of the trench sites. In this study, as a result, we identified that terrestrial LiDAR data can be practical to increase reproducibility of geological field studies and easily accessible by researchers and students in Earth Sciences.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.2
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• pp.134-140
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• 2021

This study was carried out to study the effect of supplementary nitrogen fertilization application time according to regrowth date on growth date on growth characteristics, feed value, and productivity of Italian ryegrass (Lolium multiflorum Lam.; IRG) from 2019 to 2021 in Cheonan region. In order to determine the regrowth time, IRG was cut from experimental plots 3cm above soil level and the time when 1cm grew was judged as the regrowth time. The regrowth dates were February 15^th and February 12th in 2020 and 2021 respectively. The experimental design was a randomized block design with three replications. The treatments were no fertilizer, immediately after the regrowth period, after 10 days of the regrowth period, and after 25 days of the regrowth period. Dry matter yield of IRG was significantly influenced by the supplementary N-fertilization application time. Dry matter yield was reduced for the delayed application time. The dry matter yield of immediately after the regrowth period was approximately 34.8 % higher than that no fertilizer application. In delaying the supplementary N-fertilization application time resulted in increased crude protein content. However, no significant statistical difference was neutral detergent fiber and acid detergent fiber(p>0.05). After wintering, productivity of IRG reduced for the delayed application time. Therefore, it is essential to application N-fertilizer immediately after the regrowth period for high productivity of IRG.