• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.533-540
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• 2021

High-resolution satellite images have high potential to acquire geospatial information over inaccessible areas such as Antarctica. Reference data are often required to increase the positional accuracy of the satellite data but the data are not available in many inland areas in Antarctica. Therefore this paper presents a multi-image RPCs (Rational Polynomial Coefficients) sensor modeling without any ground controls or reference data. Conjugate points between multi-images are extracted and used for the multi-image sensor modeling. The experiment was carried out for Kompsat-3A and showed that the significant accuracy increase was not observed but the approach has potential to suppress the maximum errors, especially the vertical errors.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.561-571
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• 2020

Seven techniques widely used in the geodetic transformations have been reviewed and compared to figure out their theoretical characteristics. A series of numerical tests were performed about four data sets. This was followed by result analyses in terms of transformation residuals and accuracies together with some hypothesis testings based on the student-t distribution to confirm the statistical significance of the techniques. In the case of the transformation between the geodetic frames implemented in the same system, no statistical significance was revealed in the results of the 3D transformation techniques, even if the testing area becomes large as the Asia-Oceania continent. Among the 2D transformations, it was possible for the NTv2 grid modeling technique to deliver improved transformation accuracy. Finally, it was possible from the results analyzed in this study to propose the Helmert transformation to geodetic control points and the NTv2 technique to the 2D spatial data transformation of the geodetic systems.

• Korean Public Administration Review
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• v.48 no.3
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• pp.413-436
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• 2014

본 논문은 청주·청원과 전주·완주의 행정구역 통합과정을 비교·분석하였다. 2009년 두 지역의 통합은 모두 무산되었다. 그러나 2010년부터 이루어진 재시도에서 청주·청원은 통합에 성공한 반면 전주·완주의 통합은 또다시 무산되었다. 행정구역 통합을 설명하는 기존의 연구들은 구조 및 환경 등 외생적 요인에 초점을 두고 있어 역사적 배경, 지리적 조건, 통합의 시기 등에서 여러 유사점이 있는 두 지역의 비교연구에는 적합하지 않다. 본 논문은 특히 전주·완주와 청주·청원의 행정구역 통합 결과의 차이가 나타난 이유로 정책중개자의 역할에 초점을 맞추었다. 구체적인 통합 결과의 차이를 살펴보기 위해 통합절차를 5단계로 나누어 그 충족 정도를 분석하였다. 정책중개자는 그 정책선호와 지위를 기준으로 (1) 민-관 선호 정책중개자, (2) 관단독 선호 정책중개자, (3) 민단독 선호 정책중개자, (4) 선호 없음의 네 가지 역할로 구분하였다. 본 논문의 분석 결과에 따르면, 제1기(2009년~2010년)에는 두 지역 모두 민단독 선호 정책중개자가 나타났다. 그 결과 전주·완주에서는 여론조사에서, 청주·청원에서는 의회의결단계에서 그 통합시도가 무산되었다. 제2기(2010년~2013년)에는 전주·완주에서는 정책중개자 유형이 관단독 선호 정책중개자 유형으로 바뀌어 주민투표단계까지 도달하는 데 그쳤으나, 청주·청원에서는 민-관 선호 정책중개자로 바뀌어 최종 통합시 설치법 단계까지 도달해 통합이 완성되었다.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.47-56
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• 2014

Recently, the velocity of sea-level rising has increased due to the global warming and the natural disasters have been occurred many times. Therefore, there are various demands for the integration of vertical reference datums for the ocean and land areas in order to develop a coastal area and prevent a natural disaster. Currently, the vertical datum for the ocean area refers to Local Mean Sea Level(LMSL) and the vertical datum for the land area is based on Incheon Mean Sea Level(IMSL). This study uses 31 points of Tidal Gauge Bench Mark (TGBM) in order to compares and analyzes the geometric heights referring LMSL, IMSL, and the nationally determined geoid surface. 11 points of comparable data are biased more than 10 cm when the geometric heights are compared. It seems to be caused by the inflow of river, the relocation of Tidal Gauge Station, and the topographic change by harbor construction. Also, this study analyze the inclination of sea surface which is the difference between IMSL and LMSL, and it shows the inclination of sea surface increases from the western to southern, and eastern seas. In this study, it is shown that TGBM can be used to integrate vertical datums for the ocean and land areas. In order to integrate the vertical datums, there need more surveying data connecting the ocean to the land area, also cooperation between Korea Hydrographic and Oceanographic Administration and National Geographic Information Institute. It is expected that the integrated vertical datum can be applied to the development of coastal area and the preventative of natural disaster.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.577-589
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• 2021

Drone mapping systems can be applied to many fields such as disaster damage investigation, environmental monitoring, and construction process monitoring. To integrate individual sensors attached to a drone, it was essential to undergo complicated procedures including time synchronization. Recently, a variety of composite sensors are released which consist of visual sensors and GPS/INS. Composite sensors integrate multi-sensory data internally, and they provide geotagged image files to users. Therefore, to use composite sensors in drone mapping systems, mapping accuracies from composite sensors should be examined. In this study, we analyzed the mapping accuracies of a composite sensor, focusing on the data acquisition area and pre-calibration effect. In the first experiment, we analyzed how mapping accuracy varies with the number of ground control points. When 2 GCPs were used for mapping, the total RMSE has been reduced by 40 cm from more than 1 m to about 60 cm. In the second experiment, we assessed mapping accuracies based on whether pre-calibration is conducted or not. Using a few ground control points showed the pre-calibration does not affect mapping accuracies. The formation of weak geometry of the image sequences has resulted that pre-calibration can be essential to decrease possible mapping errors. In the absence of ground control points, pre-calibration also can improve mapping errors. Based on this study, we expect future drone mapping systems using composite sensors will contribute to streamlining a survey and calibration process depending on the data acquisition circumstances.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.628-633
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• 2018

The accuracy of GNSS depends on several factors from the equipment used in data processing because GNSS positioning can be used differently depending on the accuracy required. In the case of the control point surveying requiring high accuracy, GNSS surveying is performed using the relative positioning method, and the observation time and data processing s/w are used differently depending on the class of the control points. On the other hand, the accuracy of academic software depends on the skill of the user, so it may be better to use commercial software in the case of a short baseline. In this study, the results of GNSS survey data were compared using scientific software and commercial software. The results showed that the horizontal position showed a difference of less than 2 cm and the height showed a difference of less than 5 cm. These differences were found to be in the error ranges specified in the unified control point survey regulations. Based on the above results, the commercial s/w can be used for GNSS data processing at the midterm baseline rather than the long baseline.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.54-63
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• 2013

In this paper, we evaluate the accuracy of the vertical positioning by distance using Network RTK-GPS. The experimental results confirm that Network RTK-GPS method can acquire data quickly and accurately than conventional leveling methods so that the Network RTK-GPS method is a relatively efficient and economical way for the vertical positioning. Results of validation using permanent GPS stations indicate that visible satellites, PDOP, and VDOP are very good for the vertical positioning. Integrated reference points such as U0997 and U0921 are satisfied with 3 ratings in the rules of public leveling and all the rest are proved improper. When the vertical positioning using Network RTK-GPS is implemented, the geoid height of EGM2008 should be applied for leveling. If the number of geodetic satellite are increasing in the near future, the vertical positioning using Network RTK-GPS can be possible in all the range.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.2
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• pp.49-72
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• 2018

The purpose of this study is to analyze the structure, and contents of the US national school library standards presented in the document National School Library Standards for Learner, Librarian and School Libraries made by AASL, and to provide basic information to refer to the direction and contents of Korean school library standards. AASL's National School Library Standards provide Learner Standards, School Librarian Standards, School Library Standards and Standards Integrated Frameworks that incorporate three previous standards, and emphasize the growth of learners and school librarians' competency by focusing on the educational activities of learners and school librarians. With the physical environment of the school library being somewhat established, it is necessary to establish standards for the educational content and competency of learners and teachers. And it is necessary to pay more attention to the materials including the contents of education.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.359-367
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• 2020

WSNs as the main technology of IoT often deliver information or authenticate based on location. Thus, verifying location information is essential. This paper aims to present the comprehensive analysis and classification of location verification techniques in WSN. For this, classification criteria are suggested based on the result of feature analysis of existing techniques. In addition, the existing techniques are classified according to the suggested criteria, and each characteristic and development direction are described. The result of this paper is expected to be a useful reference material when designing a new technique.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.217-222
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• 2010

The geoid is the level surface that closely approximates mean sea level and usually used for the origin of vertical datum. For the computation of geoid, various sources of gravity measurements are used in South Korea and, as a consequence, the geoid models may show different results. however, a limited analysis has been performed due to a lack of controlled data, namely the GPS/Leveling data. Therefore, in this study, the gravimetric geoids are compared with the geodetic geoid which is obtained through the GPS/Leveling procedures. The gravimetric geoids are categorized into geoid from airborne gravimetry, geoid from the terrestrial gravimetry, NGII geoid(geoids published by National Geographic Information Institute) and NORI geoid(geoi published by National Oceanographic Research Institute), respectively. For the analysis, the geometric geoid is obtained at each unified national control point and the difference between geodetic and gravimetric geoid is computed. Also, the geoid height data is gridded on a regular $10{\times}10-km$ grid so that the FFT method can be applied to analyze the geoid height differences in frequency domain. The results show that no significant differences in standard deviation are observed when the geoids from the airborne and terrestrial gravimetry are compared with the geomertric geoid while relatively large difference are shown when NGII geoid and NORI geoid are compared with geometric geoid. Also, NGII geoid and NORI geoid are analyzed in frequency domain and the deviations occurs in long-wavelength domain.