• Title/Summary/Keyword: Field surveying

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Evaluation of Geometric Error Sources for Terrestrial Laser Scanner

  • Lee, Ji Sang;Hong, Seung Hwan;Park, Il Suk;Cho, Hyoung Sig;Sohn, Hong Gyoo
    • Journal of Korean Society for Geospatial Information Science
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    • v.24 no.2
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    • pp.79-87
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    • 2016
  • As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.

A Study on the Hydroulic Phenomenon at the Douvstream Channel of the Drainage Sluice (배수갑문 물받이의 수리현상에 관한 연구)

  • 이희영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.18 no.4
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    • pp.4218-4225
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    • 1976
  • To insure the safety of the drainage sluice, topogrophical change due to erosion as well as capability of discharging the design flow in a very important factor. In consideration of the fact that the drainage sluice is built in the sea, its construction has many topographically restricted problems and naturally requires a completeness of research and experiment. This thesis is a comparative and analytic study of discharging flow acting on the erosion at the bottom of the structure on the basis of the measured velocity on the downstream channel of the drainage sluice. (1) The measured velocity shows a little higher values than the computed velocity, because the measured velocity was observed at the surface of the stream. There fore, it is reasonable that the compated velocity should be taken in this study. (2) The field observation was conducted to have the measurement of the flow velocity without surveying the area of flow. Therefore, the coefficient of discharge could not be computed. The survey of the area of flow is planned to be conducted along with the measurement of the flow velocity. (3) The apron of the drainage sluice is free discharging type and it was designed to be about 80m in length less than it should be. (4) The apron of free flow discharging type should have a solid foundation to protect the structure by preventing erosion damage to upstream and downstream channels against weathering of rock and strong torrent. Whether free flow discharging type or energy-dissipating type is best chosen depends on the topographical condition of the forage site, therefore, there would be a comparative study before the final decision was made about the protrection for the structure. (5) It is considered to be appropriate that the design and construction of the drainage sluice should have a complete study which is based on hydraulie model test before the type of protection is decided. (6) It is much requested that a variety of experiment equipments be installed and observed to study the protection for the drainage sluice.

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Method of Correcting Hyperspectral Image for Seabed Material Analysis of Coastal Area (연안 해저 재질 분석을 위한 초분광영상의 보정 방법)

  • SHIN, Myung-Sik;SHIN, Jung-Il;KIM, Ik-Jae;SUH, Yong-Cheol
    • Journal of the Korean Association of Geographic Information Studies
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    • v.19 no.2
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    • pp.107-116
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    • 2016
  • Airborne or spaceborne remote sensing can increase the efficiency of seabed material surveys compared with field surveying using a vessel. For the same seabed material, the optical remote sensing image shows variation in the reflectance depending on the water depth, which is due to the absorption and scattering by the water column. This study suggests a correction procedure to use the hyperspectral image for seabed material analysis. The study is conducted in the coastal area from Sacheonjin Port to Gyungpo Beach in Gangwon-do. The hyperspectral image is acquired using the CASI-1500 sensor. The diffuse attenuation coefficient is estimated for each band through regression models between the water reflectance and depth. Then, the coefficient is applied to each band of the image. As a result, the completely corrected image can be interpreted for a deeper area, although the interpretable area is very shallow without water column correction. Additionally, the water column corrected image shows decreased variation of reflectance with various water depths.

Survey of actual status of ecological environment elements of certification schools of environment friendly architecture (친환경건축물인증학교의 생태환경요소에 대한 실태조사)

  • Song, Byung-joon;Cho, Jin-il
    • The Journal of Sustainable Design and Educational Environment Research
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    • v.7 no.1
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    • pp.39-55
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    • 2008
  • The purpose of this study is to suggest improvement of certification standards of environment friendly architecture in ecological environment field by surveying and analyzing actual status of actual certification schools of environment friendly architecture per ecological environment elements through extracting ecological environment elements which is possible to analyze in quantity certification standards of environment friendly architecture. As contents of the study, first, certification as an examination on certification system of environment friendly architecture, summary of certification system of environment friendly architecture, ecological environment elements which is possible for quantitative analysis of ecological environment certification standards were extracted. Second, actual status of ecological environment elements per school grade, region, and population increase by collecting actual data of certification schools of environment friendly architecture. Third, using analysis data of ecological environment elements, ecological area ratio of certification schools of environment friendly architecture per weighted values of space types was calculated and the results were analyzed as the follows. (1) In case of preliminary certification out of total objects of investigation schools was average 34.06% but in this case of certification, it was reduced to 33.07%. However, it is difficult to make judgment as actual evidence data since ecological area ratio of actual preliminary certification is data based on drawing planes. Therefore, in case of this certification, elementary schools was investigated at average 33.11%, middle schools 34.81%, and high schools 31.28% and middle school showed the highest relatively. (2) Besides, average composition ratio of ecological area ratio was 63.04% in case of this certification regardless of school grade and region and it was analyzed that about 70% of ecological area ratio is composed of the natural based green area including pure natural based green land and 6.89% of ecological learning institute.

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Geotechnical Information Application System Using 3D Geo-Spatial Information Technique (3차원 공간정보 기술을 활용한 지반정보 활용시스템 개발)

  • Lee, Ji-Young;Jang, Yong-Gu;Kang, In-Joon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2D
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    • pp.335-342
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    • 2011
  • Geotechnical Information which had been constructing and offering by Minister of Land, Transport and Maritime Affairs (MLTM) has been target on the whole of country. Today, the 100,000 number of geotechnical data has been managed as 2d GIS database. But, it is difficult to apply this database for analyzing and designing geotechnical works. In this paper, we have developed Geotechnical Information Application System (GIAS) based 3d geo-spatial information technique for the effective uses. First, GIAS based on GIS framework was implemented to effectively find out spatial geologic structure of study area. Second, we invited some experts from each field and listened their opinions. According to the surveying on the applicability-ratio, the experts showed higher interest in this system. In this study, it was verified that the 3d GIS-based system was very useful for the usability-ratio.

Development of Network-Based Online GPS Baseline Processing System (네트워크 기반 온라인 GPS 기선해석 시스템 개발)

  • Kim, Su-Kyung;Bae, Tae-Suk
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.2
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    • pp.138-146
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    • 2011
  • With the increased use of GPS in the field of various applications including surveying, the request for fast and precise positional information has increased. Several countries such as USA, Canada, and Australia have already been operating Internet-based automatic GPS data analysis system using e-mail and FTP. Expanding GPS market, it is necessary to establish automatic GPS baseline processing system that is accessible via Internet. The system developed in this study is operating on the web, and it allows the users to access easily regardless of time and place. The main processing engines are Bernese V5.0 and PAGES. They process user data with three GPS CORS(Continuously Operating Reference Station), and then send the report to the users through e-mail. This system allows users to process high accurate GPS data easily. It is expected that this system will be used for various GPS applications such as monitoring large-scale structures and providing spatial information services in private sector.

A Study on Perceptions of Scientifically Gifted Middle School Students about Engineering Design Process (중학교 과학 영재들의 공학 설계 과정에 대한 인식 조사 연구)

  • Song, Shin-Cheol;Han, Hwa-Jung;Shim, Kew-Cheol
    • Journal of The Korean Association For Science Education
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    • v.37 no.5
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    • pp.835-846
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    • 2017
  • The purpose of this study is to investigate the perceptions of scientifically gifted middle school students about their engineering design process according to gender and talent division. The instrument in surveying their perceptions about the engineering design process consists of 24 items (Likert 5 point type) five domains: problem definition, information collection and utilization, idea generation, inquiry performance, and teamwork (communication, cooperation, leadership). A total of 102 scientifically gifted students participated in the survey, according to gender (69 males and 33 females) and talent divisions (physics, biological sciences, software, mathematics, space-geological sciences, and chemistry). They had a high level of awareness of their engineering design ability. It is necessary to develop a customized gifted-education program so that their talent in their field of interest can be fully displayed according to the gender and talent division. In addition, the teaching and learning methods and strategies of the engineering design program for the scientifically gifted middle school students should be established to fully reflect the practical needs of the talented.

A Exploratory Research on the Construction Techniques of Ponds in Korean Royal Palace Gardens (우리나라 궁궐 지당의 조성기법에 관한 기초 조사 연구 -경복궁, 창덕궁, 창경궁의 지안 축석 기법을 중심으로-)

  • 이상민;정수정;허학영;안동만
    • Journal of the Korean Institute of Landscape Architecture
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    • v.29 no.1
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    • pp.124-130
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    • 2001
  • We have increasing number of new ponds planned and designed in traditional styles. However, many of the stoneworks at the edges of those new ponds are not the characteristics of our traditional ponds. This study is aiming at surveying and analysing the building techniques of Korean traditional water edges built with stones, by investigating selected ponds in royal palace gardens. This study was conducted through field investigation and literature reviews. Nine ponds from Gyongbok Palace, Changdeok Palace, and Changgyong Palace, which have many well-preserved ponds of various styles, were surveyed. First of all, the building materials (stones), or the kinds and sizes of stones used for the edges of ponds were surveyed. Secondly, construction methods, or the height and techniques of buildings stone walls were surveyed. Major findings were, first, the edges of most ponds constructed with granite Jangdaeseok, usually 120cm-140cm long, and 30cm-40cm thick. The only exceptions were those ponds which seemed to have been influenced by Japanese style. Second, typical pond ages were up-right vertical walls. Granite jangdaeseoks were piled-up 2 stories or up to six stories. Exceptions were Bandoji Pond and Chundangji Pond which had been constructed during latest period(King 'Ghojong' period). Third, heith of stone walls were between 60cm and 220cm. The depth of ponds were about 150cm or less, and the rest of the edge wall height was freeboard. Though the results of this study was not made by precise investigation and actual measurement, they could be fundamental information and data for the traditional styles of the Chosun dynasty Palace. It is believed that continuous researches on this matter will result in important and fundamental data of the establishment of traditional water edges.

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Features and Issues of an Urban Community by Analysing Residents' Awareness and Attitude (주민의 인식과 태도로 본 도시 공동체의 현황과 과제 - 대구 동구 안심지역을 사례로 -)

  • Lee, Young A
    • Journal of the Korean association of regional geographers
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    • v.20 no.3
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    • pp.269-281
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    • 2014
  • Urban communities have been recently highlighted as an alternative idea in the field of urban regeneration, social economy and so on. Urban communities should not be understood as an ideal, but the way urban communities work in reality also should be analysed. This paper aims to find out what urban communities really mean and who are involved in urban communities. The paper explores the features and issues of unban communities by surveying residents in Ansim area, Dong-gu, Daegu city. The paper analyses the relation between participation and community features: residents' socio-economic features, residence features, social relationship with their neighbours and the sense of community. The survey outcome shows that middle income, higher educated residents living in apartment complex are relatively more involved in community activities. Moreover, those who have more relationship with their neighbours have participated in community activities more than those who do not have any. As a consequence, this paper carefully states that the urban community is middle class-oriented and such feature could cause other residents' limited opportunities to access information about their own community and lead to social exclusion. This paper suggests that urban community groups need 'soft solidarity' between social classes.

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Knowledge of Housing in Home Economics Textbooks from 1908 to 1914 (고등여학교 가사과목 교과용도서의 주거지식(1908-1914))

  • Kim, Myung-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.7
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    • pp.2648-2653
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    • 2010
  • Three books of home economics were published in Korea 1907 and approved as textbooks for women's education by Korean government from 1908 to 1910 and by the Choseon Government-General from 1912 to 1914. The textbooks contained modern knowledge about housing which was focused on hygine matters and most systematic among the knowledge of that time. The original book of the three was Sinsen Gajunhak(新選家政學) by Shimoda Yutako published in Japan 1990 after her surveying western home economics knowledge. It means the modern housing knowledge educated in Korea around 1910 was affected by Western modern thinking in home economics field that gave the responsibility of housing cleanness for family members' health to housewives. So the knowledge even made the educated women to practice their learning only as wives, which was still traditional.