• 융복합기술연구소 논문집
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• 제9권1호
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• pp.31-36
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• 2019

After 30 years of KKP model analysis and extended 30 years of accuracy analysis, the unique correlation and various problems between measured horizontal surface insolation and measured weather data are found in this paper. The KKP model's 10yrs daily total horizontal surface insolation forecasting was averaged about 97.7% on average, and the forecasting accuracy at peak times per day was about 92.1%, which is highly applicable regardless of location and weather conditions nationwide. The daily total solar radiation forecasting accuracy of the modified KKP cloud model was 98.9%, similar to the KKP model, and 93.0% of the forecasting accuracy at the peak time per day. And the results of evaluating the accuracy of calculation for 30 years of KKP model were cloud model 107.6% and cloud model 95.1%. During the accuracy analysis evaluation, this study found that inaccuracies in measurement data of cloud cover should be clearly assessed by the Meteorological Administration.

• 한국측량학회지
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• 제25권3호
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• pp.223-230
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• 2007

도시의 집중화로 지하시설물이 폭발적으로 증가하였으며, 그에 따른 지하시설물도의 중요성이 부각되고 있다. 하지만, 부정확한 지하시설물도와 지하시설물에 대한 관리부재로 인하여 크고 작은 사고가 계속하여 발생하고 있는 실정이다. 또한 지하시설물도는 자료의 최신성과 정확성이 확보되어야 하나, 현재의 지하시설물도는 각 기관별 작성 및 갱신체계를 가지고 있어, 자료의 최신성과 정확성을 검증하기 힘든 상황이다. 따라서, 본 논문에서는 서울특별시에 소재한 6대 유관기관의 지하시설물도 위치정확도를 분석하기 위해 3년간 지하시설물에 대한 현장 조사/탐사 작업과 기준점에 기반한 위치측량을 수행하였다. 이를 바탕으로 연차별, 기관별 지하시설물도의 위치정확도를 비교분석하였으며, 그 결과 지하시설물도의 평균 73cm(2004), 78cm(2005) 그리고 75cm(2006)의 위치정확도 결과값을 획득하였다.

• 한국측량학회지
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• 제38권5호
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• pp.415-423
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• 2020

GNSS (Global Navigation Satellite System) is mostly used for high-precise surveys due to its accuracy and efficiency. But this technique does not always fulfill the demanding accuracy in harsh operational environments such as urban canyon and forest. One of the remedies for overcoming this barrier is to compose a heterogeneous surveying network by adopting terrestrial measurements (i.e., distances and angles). Hence, this study dealt with the adjustment of heterogeneous surveying networks consisted of GNSS baseline vectors, distances, horizontal and vertical angles with a view to enhancing their accuracy and so as to derive an appropriate scheme of the measurement combination. Reviewing some technical issues of the network adjustments, the simulation, and experimental studies have been carried out, showing that the inclusion of the terrestrial measurements in the GNSS standalone overall increased the accuracy of the adjusted coordinates. Especially, if the distances, the horizontal angles, or both of them were simultaneously adjusted with GNSS baselines, the accuracy of the GNSS horizontal component was improved. Comparing the inclusion of the horizontal angles with those of the distances, the former has been more influential on accuracy than the latter even though the same number of measurements were employed in the network. On the other hand, results of the GNSS network adjustment together with the vertical angles demonstrated the enhancement of the vertical accuracy. As conclusion, this paper proposes a simultaneous adjustment of GNSS baselines and the terrestrial measurements for an effective scheme that overcomes the limitation of GNSS control surveys.

• Journal of Positioning, Navigation, and Timing
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• 제4권2호
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• pp.79-85
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• 2015

Existing Differential GPS (DGPS) pseudorange correction (PRC) generation techniques based on a virtual reference station cannot effectively assign a weighting factor if the baseline distance between a user and a reference station is not long enough. In this study, a virtual reference station DGPS PRC generation technique was developed based on an enhanced inverse distance weighting method using an exponential function that can maximize a small baseline distance difference due to the dense arrangement of DGPS reference stations in South Korea, and its positioning performance was validated. For the performance verification, the performance of the model developed in this study (EIDW) was compared with those of typical inverse distance weighting (IDW), first- and second-order multiple linear regression analyses (Planar 1 and 2), the model of Abousalem (1996) (Ab_EXP), and the model of Kim (2013) (Kim_EXP). The model developed in the present study had a horizontal accuracy of 53 cm, and the positioning based on the second-order multiple linear regression analysis that showed the highest positioning accuracy among the existing models had a horizontal accuracy of 51 cm, indicating that they have similar levels of performance. Also, when positioning was performed using five reference stations, the horizontal accuracy of the developed model improved by 8 ~ 42% compared to those of the existing models. In particular, the bias was improved by up to 27 cm.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 추계학술발표회 논문집
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• pp.123-128
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• 2003

Data acquired from digital Imagery were processed via Delphi, an object-oriented programming language to develop a computer aided program, that allows us to build up the information on road horizontal alignment(BC, EC, R, IP). And the developed program could maximize the visual effects better than traditional programs, because it used many image data. Comparing with data from traditional horizontal alignment extraction programs based on the principle of least square method, the data acquired by horizontal alignment information and kinematic GPS out of the developed road information systems showed the enhanced accuracy of IP value up to about 2m in the direction of X, Y axes, where the accuracy of curve radius(R) becomes enhanced up to about 2.5 m.

• 대한치과보철학회지
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• 제42권2호
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• pp.238-247
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• 2004

Statement of problem: Major objective in making on implant-supported prosthesis is the production of superstructure that exhibits a passive fit when connected to multiple abutments. One requirement to ensure passive fit is to make an accurate impression. Purpose : The purpose of this study was to compare the accuracy of master cast fabricated by using different impression methods at the different impression levels. Material and method: The master model used in this study was resin block having low implant analogs. Impression method studied were 1) direct method on fxiture level (Group FIX-D), 2) indirect method on fixture level(Group FIX-I), 3) modified indirect method on fixture level(Group FIX-M), 4) direct method on abutment level(Group AB-D) and 5) indirect method on abutment level(Group AB-I). Each of the five groups took 10 impressions. Fifty impressions were made for master cast by using Impregum $F^{(R)}$ impression material loaded on individual tray. Three dimensional measuring microscope was used to measure the inter-implant distance. Error rate of each inter-implant distance were calculated and evaluated. Results : The results were as follows. 1. Group FIX exhibited higher accuracy than group AB. 2. In group FIX, modified indirect method showed the highest accuracy, while indirect method showed the lowest accuracy. In group Ab, indirect method showed the higher accuracy than direct method. 3. Group FIX showed larger horizontal error than group AB. But, group AB showed the larger vertical error than group FIX. 4. Group Fix-M showed smallest vertical and horizontal error. Conclusion: An impression method have more effect on accuracy of master model than an impression level. A modified indirect method showed smallest vertical and horizontal error.

• 대한공간정보학회지
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• 제10권4호
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• pp.95-103
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• 2002

수치지도의 정확도가 사용자의 요구수준에 미치지 못할 경우 이는 무용지물이 될 것이며 막대한 국가예산을 낭비하는 결과를 가져올 수 있다. 이러한 정확도 문제를 해결하기 위해서는 명확한 수치지도의 축척별 위치정확도에 관한 규정이 빨리 이루어져야 하고, 수치지도의 정확한 정보를 사용자에게 제공함으로써 사용자가 각자의 GIS응용분야에 적합하게 수치지도를 사용할 수 있도록 해야한다. 이를 위해서는 다양한 작업방법에 의해서 제작된 기존의 수치지도에 대한 위치정확도의 평가가 요구되고 있다. 따라서 본 연구에서는 1:1,000, 1:5,000 축척의 수치지도상에서 수평위치의 정확도를 평가하기 위해서 Total Station 장비를 이용하여 현지에서 선정된 시설물의 수평위치를 측정하였으며, 이 결과를 이용하여 표준편차를 구하고 T-Test를 실시하여 편의(Bias) 존재의 유무를 확인하여 수평위치 정확도를 평가하였다.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.363-366
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• 2007

Road Design is being reached to the working design to produce drawings, calculate construction quantity and cost, through the basic design that contained feasibility study and all impact assessment. In general, to plan the route we use topographic map. The vertical positional accuracy is 30cm and horizontal positional accuracy is 35cm in 1:1,000 scale topographic map. In LiDAR, vertical positional accuracy is 15cm and horizontal positional accuracy is 30cm. So if we use LiDAR on road design, more accurate earth-volumn will be calculated when we plan the route. In this paper we try to find the method to use the LiDAR data on road design by drawing the profile and cross sectional view and comparing the earth-volumn to the road that working design is in process adopting the topographic map and LiDAR data.

• 한국해양공학회지
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• 제11권2호
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• pp.113-121
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• 1997

With the increase use of electromagnrtic distance measuring equiment, is is required that we need to study the higher dimensional applications and detail technical methods. The purpose of this paper is to improve the accuracy of ocean construction surveying and computer programming for determining of horizontal position of a quadrilateral by measuring line on traverse surveyng, trigulation and trilateration. Aa long distance measurements with high accuracy became possible by the apperance of EDM distance measuring instruments, we induced correct adjustment equation through angle condition and area conditionequation. After that we compared and experimental model. From its a result of the practical applicationto quadrilateral, it has been found that its triangulation and traverse surveying algorithms provide better accuracy than trilateration.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.155-161
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• 2018

Recently, the development of sensor technology has led to an increase in research on unmanned aerial photogrammetry in various fields such as digital mapping, monitoring, cadastral survey, coastal survey, and topographic survey. However, existing studies are mainly limited experiments and analysis of specific application field, which is insufficient to demonstrate the validity of unmanned aerial photogrammetry for geospatial information construction. In this study, the studies related to the accuracy of unmanned aerial photogrammetry were investigated. The flight altitude and accuracy of horizontal direction is proportional to the GSD by analyzing the results of the individual studies conducted on the unmanned aerial photogrammetry within the last 5 years. In addition, the accuracy of the evaluation results varied widely according to the experimental conditions, and the problems of the previous studies that lacked the number of samples to evaluate the results were identified. A total accuracy analysis of 322 checkpoints yielded an accuracy of 0.028m in the horizontal direction and 0.044m in the vertical direction. In the future, the results of this study can be used as a basis for the validity of spatial information construction using unmanned aerial photogrammetry.