• Title/Summary/Keyword: digital reference

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Validation of DEM Derived from ERS Tandem Images Using GPS Techniques

  • Lee, In-Su;Chang, Hsing-Chung;Ge, Linlin
    • Journal of Korean Society for Geospatial Information Science
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    • v.13 no.1 s.31
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    • pp.63-69
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    • 2005
  • Interferometric Synthetic Aperture Radar(InSAR) is a rapidly evolving technique. Spectacular results obtained in various fields such as the monitoring of earthquakes, volcanoes, land subsidence and glacier dynamics, as well as in the construction of Digital Elevation Models(DEMs) of the Earth's surface and the classification of different land types have demonstrated its strength. As InSAR is a remote sensing technique, it has various sources of errors due to the satellite positions and attitude, atmosphere, and others. Therefore, it is important to validate its accuracy, especially for the DEM derived from Satellite SAR images. In this study, Real Time Kinematic(RTK) GPS and Kinematic GPS positioning were chosen as tools for the validation of InSAR derived DEM. The results showed that Kinematic GPS positioning had greater coverage of test area in terms of the number of measurements than RTK GPS. But tracking the satellites near and/or under trees md transmitting data between reference and rover receivers are still pending tasks in GPS techniques.

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Short-Term Strength Deficit Following Zone 1 Replantations

  • Roh, Si Young;Shim, Woo Cheol;Lee, Kyung Jin;Lee, Dong Chul;Kim, Jin Soo;Yang, Jae-Won
    • Archives of Plastic Surgery
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    • v.42 no.5
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    • pp.614-618
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    • 2015
  • Background Hand strength deficit following digital replantation is usually attributed to the mechanical deficiency of the replanted digit. Zone 1 replantation, however, should not be associated with any mechanical deficit, as the joint and tendon are intact. We evaluate shortterm motor functions in patients who have undergone single-digit zone 1 replantation. Methods A single-institution retrospective review was performed for all patients who underwent zone 1 replantation. Hand and pinch strengths were evaluated using standard dynamometers. Each set of measurements was pooled according to follow-up periods (within 1 month, 1 to 2 months, 2 to 3 months, and after 3 months). The uninjured hand was used as reference for measurements. Results The review identified 53 patients who had undergone zone 1 replantation and presented for follow-up visits. Compared to the uninjured hand, dynamometer measurements revealed significantly less strength for the hand with replanted digit at one month. The relative mean grip, pulp, and key pinch strength were 31%, 46%, and 48% of the uninjured hand. These three strength measurements gradually increased, with relative strength measurements of 59%, 70%, and 78% for 4-month follow up. Conclusions Despite the lack of joint or tendon injury, strength of the injured hand was significantly lower than that of the uninjured hand during the 4 months following replantation. Improved rehabilitation strategies are needed to diminish the short-term negative impact that an isolated zone 1 replantation has on the overall hand strength.

Estimation of morphological change using waterline method in the Ganghwado tidal flats

  • Lee, Yoon-Kyung;Ryu, Joo-Hyung;Eom, Jin-Ah;Jo, Min-Jeong
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.22-24
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    • 2007
  • Waterline extraction is the one of widely used methods for studying changes in tidal flat environment and coastlines using multi-temporal optical images such as Landsat TM and Landsat ETM+. High dynamics of tidal currents and land reclamation which accelerate sedimentation and/or erosion cause waterline change in tidal flats. The amount of sediment deposited or eroded can be evaluated by precisely estimating waterline changes in tidal flats. The objective of this study is to detect the change of waterlines during 17 years and analyze the trends of erosion and sedimentation in the study areas. The Ganghwado tidal flat on the west coast of the Korean Peninsula was selected. The study area is famous for high dynamics of tidal currents and vast tidal flats. Land reclamation which has been carried out on a large scale is also considered as one of elements that have accelerated the environmental changes in this tidal flat. In this study, we acquired 26 waterlines from Landsat TM and Landsat ETM+ images. We extracted the waterline from each satellite image to generate a digital elevation map (DEM) which was used for reference and to compare with the other waterline which was extracted from DEM having a same tide. The result of comparison well depicted the areas of dominant sedimentation and erosion, and general trends of sedimentation and erosion according to sub-regions are also revealed during the investigation time. Results showed that erosion during a decade was dominant at the west of the Southern Ganghwado tidal flat, while sedimentation was dominant at the wide channel between the Southern Ganghwado tidal flat and the Yeongjongdo tidal flat. This area has been commonly affected by high currents and sedimentation energy. Although we were not able to verify the accuracy of the waterline changes, this result clearly showed the waterline change and therefore, the waterline extraction method used in this study has proven as an effective tool for long term tidal change estimation.

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Accuracy Analysis of Coastal Area Modeling through UAV Photogrammetry (무인항공측량을 통한 해안 지형 모델링의 정확도 분석)

  • Choi, Kyoungah;Lee, Impyeong
    • Korean Journal of Remote Sensing
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    • v.32 no.6
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    • pp.657-672
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    • 2016
  • Coastal erosion happens frequently in many different types. To control coastal erosion zone effectively and establish response plans, we need to accumulate data indicating topography changes through monitoring the erosion situation continuously. UAV photogrammetric systems, which can fly autonomously at a low altitude, are recommended as an economical and precision means to monitor the coastal zones. In this study, we aim to verify the accuracy of the generated orthoimages and DEM as a result of processing the UAV data of a coastal zone by comparing them with various reference data. We established a verification routine and examined the possibilities of applying the UAV photogrammetric systems to monitoring coastal erosion by checking the analyzed accuracy by the routine. As a result of verifying the generated the geospatial information from acquired data under various configurations, the horizontal and vertical accuracy (RMSE) were about 2.7 cm and 4.8 cm respectively, which satisfied 5 cm, the accuracy required for coastal erosion monitoring.

Accuracy Assessment of LiDAR DEM Using GPS (GPS에 의한 LiDAR DEM의 정확도 평가)

  • Kang, Joon-Mook;Yoon, Hee-Cheon;Lee, Chang-Bok;Park, Joon-Kyu
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.5
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    • pp.443-451
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    • 2006
  • DEM has been used for various purposes overall fields of engineering, the fields of civil engineering, military, communication, environment, and so forth and its applications are being extending increasingly. It is well hewn that LiDAR DEM is definitely superior to the other surveying methods. But LiDAR DEM run short of a full study about vertical accuracy. In order to assess LiDAR DEM, total 35 stations were selected and surveyed by GPS for utilizing as reference data. And then accuracy of LiDAR DEM was analyzed by comparison between both LiDAR DEM and CPS surveying. The RMSE of ${\pm}0.109m$ was shown in vertical direction. It is within the permissible accuracy required for mapping on a scale of 1 to 500 and 1 to 1000 on the mapping rule notified by the National Geographic Information Institute. It is expected that the results of this study will be fully used in the field of large scale DEM generation and be utilized as basic information in applied field of LiDAR DEM.

Accuracy Assessment of Fishery Map Conversion to World Geodetic System (어장기본도 세계측지계 변환에 따른 정확도 분석)

  • Lee, Seung-Yeol;Lee, Byoung-Kil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.6
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    • pp.631-639
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    • 2011
  • There are problems in using existing fisheries maps, because of deterioration of paper maps, as well as various coordinate systems. In this study, accuracy of fishery maps in World Geodetic System are evaluated. Materials on fishery rights in the Jeollanam-do Province, a study area, used many kind of coordinate systems. During digitization, these coordinate systems have been converted and unified in one World Geodetic System, and one projection origin. In this research, the accuracy of the products of digitization is verified using DGPS surveying. The RMSEs are minimum of 4.62m(at the Younggwang Seas) to maximum of 17.47m(at the Jangheung Seas), and average of 11.97m. The results shows that the digitized fishery maps meet the accuracy standard of 1/25,000 digital topographic maps.

A Literature Review and Analysis of Dosimetry in Panoramic Radiography (파노라마 촬영의 피폭선량에 관한 문헌분석 연구)

  • Kweon, Dae-Cheol;Dong, Kyung-Rae;Jung, Jae-Eun;Lee, Kyeong-Hee;Kim, Soo-Kyung;Kim, Wook-Tae;Lee, Cheong-Jae;Song, Woon-Heung;Ma, Sang-Chull
    • Journal of radiological science and technology
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    • v.33 no.1
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    • pp.1-10
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    • 2010
  • Dental panoramic radiography is an imaging technique which shows the information of teeth, jaws and superficial structures on a single image. In this study, we propose the clinical dose reference for dental panoramic radiography. Dental panoramic radiography is an application which can increase the radiation does of oral cavity. It is very important to study the real condition of management for these panoramic X-ray equipments. Since there was no researches on dental panoramic equipments in domestic and foreign study groups, we measured and analyzed the dose such as effective dose, DAP and DWP of panoramic radiography.

A Study on Revitalization of Library Service for the Alienated Class (정보취약계층을 위한 도서관 서비스 활성화 방안에 관한 연구)

  • Nam, Young-Joon
    • Journal of the Korean Society for Library and Information Science
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    • v.41 no.4
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    • pp.49-68
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    • 2007
  • To promote information service and to encourage active participation from the group categorized as the alienated class(group of people) this study suggests the basic concepts and strategy for the information services to alienated class who does not have full public library services. The paper classifies three separate groups of alienated groups, handicapped. poor(economically unfortunate group) and elderly group. The service shall consider their needs from their own Point of concern and interests. There are three distinctive considerations, infra structure(facility building, space. place). administrative consideration, and equipments. Infra-structure includes the planning of the space to facilitate the equipments and reference materials which will be control)ed and moderated by a librarian. Administrative service includes the development for the educational system between the end users and external experts. It also includes the individualized education system for each group Material and equipment consideration should include the each group's specific needs such as the infra-structures which is provided for the handicapped person.

The Information World of the Aged and the Role of Public Information Service : with Special Reference to Busan Area (부산지역 노령인구의 정보소외 양상과 노년층을 위한 공공 정보서비스 활성화 방안 연구)

  • Chang, Duk-Hyun
    • Journal of the Korean Society for Library and Information Science
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    • v.41 no.2
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    • pp.317-334
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    • 2007
  • This study intends to portray the everyday lives of senior citizens in Busan metro area in terms of the information use and behaviors. Employing basic qualitative data collection tools such as interviews and participant observation, the study attempts to illustrate information needs and behaviors of the aged population in their everyday lives. This paper specifically focuses on the following characteristics of information need and information-related behavior of the aged: types of everyday concerns and ways to cope with such concerns: information literacy levels and motives to get information literacy education: and characteristics of information channels of everyday information seeking and information gathering. The role that interpersonal sources play in their everyday lives has been emphasized. Some suggestions to enhance the levels of information literacy of the aged were added as conclusions.

An Investigation on the Acquisition and Preservation of Online Serials (온라인 연속간행자료수집 및 보존에 관한 연구)

  • Lee, Chi-Ju
    • Journal of the Korean Society for Library and Information Science
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    • v.41 no.2
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    • pp.359-386
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    • 2007
  • This study is to develop the operation models collection and preservation of serials only distributed online. In order to identify all of the requisite items for collection and preservation of the online serials, it conducts Delphi Technique researches with panels of experts from public institutions, organizations, and research institutions. It also deduces the 68 necessary detailed items to develop the operation models for preserving the online serials, and suggests 57 detailed items selected from the compatibility analysis with the investigation and examination of compatibility and urgency. It suggests the automated collection plan of contents with the application of RSS technology of transfer protocol to provide users the updated information from the sites where the contents and data have been constantly and frequently updated. This study strives to design the collection and preservation processes suitable for the online serials.