• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.43-48
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• 2008

Purpose: This study is to evaluate reliability of geometrical optics properties of spectacle lenses by using ISO and the medical instrument standard of KFDA, which are being sold in Korea. Methods: We used samples of three hundred and ninety eight spectacle lenses of eight company in total. Refractive indices of each samples which were used in experiment were classified into three groups of medium index (1.55~1.56), high index (1.60~1.61) and extra high index (1.67). Results: Conformity of refractive power was 81.61% in total spectacle lenses. The results showed that thickness conformity 90%, appearance conformity 85.18%, size conformity 96.23% and optical center point conformity 99.50% in total. Conclusions: We found that they deviated from the permitting value in many spectacle lenses on refractive power. The results of errors on prism power, surface inspection and optical center point showed small values in total products. In experiment of lens size and thickness, the bulk of indication rates and conformities of samples deviated from the permitting errors.

• Spatial Information Research
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• v.19 no.5
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• pp.27-35
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• 2011

The current cadastral surveying is used digital cadastral map. This map is no local confirmation. Besides, Base cadastral map drawn up 100 years ago. And Graphical cadastral characteristic is difficult to ground boundary points restoration. Due to the lack of ground boundary points can cause land dispute and Cadastral Non-Coincidence. In this Study, Understand the concept of accuracy and error, Analyzing the current regulations. Also Comparative analysis of current cadastral regulations and other surveying regulations to suggest improvements to the cadastral surveying. The results indicated a clear definition of accuracy and error and The installation of permanent ground boundary points are needed. Uniform and consistent reference point system is needed. In addition, the accuracy provided by the landowner should understand. Cadastral Surveying Regulations require specific and detailed procedures.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.65-70
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• 2011

National Geographic Information Institute provides VRS service using permanent GPS networks. VRS-RTK(Virtual Reference System-Real Time Kinematic)GPS surveying which enable to accomplish the real time-based GPS surveying has been increasingly popular. However the positioning accuracy tends to deteriorate as the distance between the rover and base station increases in the VRS-RTK GPS surveying. To analysis this problem in this study, the accuracy of VRS-RTK data was analyzed with 2 different test sites of Geoje city, Gyeongnam province within and without the permanent GPS networks in order to accomplish the cadastral supplementary control surveying. As a result of surveying accuracy analysis at two test sites, positioning errors were ${\pm}0.03m$(RMSE) in both sites. The result was that within the tolerance specified in cadastral surveying law, and indicated the possibility of VRS-RTK GPS surveying in cadastral surveying.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.145-155
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• 2007

The objectives of this study aye to develop an on-line departure time-based travel time estimation method and to determine an optimal link length for the estimation. This study developed a link-based rolling horizon logic as the travel time estimation method. In order to determine an optimal link length, the information error of the travel time provision from the user's perspective was defined and employed as a selection criterion. It was found that, when the travel time aggregation size was set as five minutes, a link length of four kilometers gave the most accurate result.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.119-124
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• 2009

In this study, the characteristics of estimating methodology for RUSLE factors such as soil erodibility factor, slope length-steepness factor, and cover management factor were reviewed and then the relative error according to each methodology was analyzed. RUSLE was applied to experimental watershed for 42 storm events and their results were compared with measured sediment yield to examine the applicability of RUSLE. As a result, this paper found that it should be necessary to consider vegetation effect for forest application of RUSLE as cover management was the most sensitive factor. Also, soil erodbility factor was calculated from data of soil series by National Academy of Agricultural Science caused sediment yield to be overestimated because there were big differences between the soil series and on-site soil texture. The 22.7% of maximum relative error was shown according to selecting the rain energy equation. In addition, it will be necessary to verify the RUSLE factors with more data in order to improve their accuracy.

• Journal of the Korean Data and Information Science Society
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• v.20 no.3
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• pp.515-526
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• 2009

Pricing based on proper risk has been one of main issues in auto insurance. In this paper, we review how the techniques of pricing in auto insurance have been developed and suggest a better approach which meets the existing risk statistically by comparison. The generalized linear model (GLM) method is discussed for pricing with different distributions. With GLM approach, the distribution of error assumed plays an main role for the best fit corresponding to the characteristics of dependent variables. Tweedie distribution is considered as one of error distributions in addition to widely used Gamma and Poisson distribution. With these different types of error assumption for estimating the proper premium in auto insurance, various modeling approaches are possible. In this paper, various modeling approaches with different assumptions for estimating proper risk is discussed and also real example is given by assuming different.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.738-745
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• 2001

In this paper, when the moving object move to the three-dimentional space, the tracking system track the moving object using the fuzzy reasoning. The joint angle el of the manipulator rotate from $0^{\circ}\; to\; 360^{\circ}$ , and the joint angle $\theta_2$rotate from$0^{\circ}\; to\; 360^{\circ}$. The fuzzy singleton is used for fuzzification and the control rule is twenty five and the fuzzy inference method is simplified Mamdani's reasoning and the defuzzification is the SCOG(Simplified Center Of Gravity) of the fuzzy controller To measure of the performance of the designed system, the fuzzy controller is compared with the CTM(Computed Torque Method) controller at the same condition. when the disturbance torque is ON, the both of CTM and fuzzy controller tracked object without error, However, the disturbance torque changed 0.4N, the CTM controller is 10 times greater than fuzzy controller at the sum of absolute error difference. The designed system is showed it's robustness against with disturbance.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.71-79
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• 2019

This research proposes an automatic generation system of aimpoints with considering 3D target shapes and CEP(circular error probability) values after determining a target and an azimuth value. In the past, users decided aimpoints manually based on experience or just chose a middle point of the 3D model. Futhermore, it was not possible to select a proper position with consideration of azimuth because users should decide aimpoints before the azimuth value was determined. To solve this problem, this research provides a automatic system to compute proper aimpoints with 3D target shapes, azimuth values and CEP. This article contains the explanation of 3 steps for generating aimpoints automatically: first, generating a reference plane and candidate entry points, then computing scores of each entry points and finally determining an aimpoint from the entry point with the highest score. Users can easily determine a final aimpoint with high probability of success using this system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.209-219
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• 2019

Satellite imagery occurs geometric and radiometric errors due to external environmental factors at the acquired time, which in turn causes false-alarm in change detection. These errors should be eliminated by geometric and radiometric corrections. In this study, we propose a methodology that automatically and simultaneously performs geometric and radiometric corrections by using the SURF (Speeded-Up Robust Feature) algorithm and the mask filter. The MPs (Matching Points), which show invariant properties between multi-temporal imagery, extracted through the SURF algorithm are used for automatic geometric correction. Using the properties of the extracted MPs, PIFs (Pseudo Invariant Features) used for relative radiometric correction are selected. Subsequently, secondary PIFs are extracted by generated mask filters around the selected PIFs. After performing automatic using the extracted MPs, we could confirm that geometric and radiometric errors are eliminated as the result of performing the relative radiometric correction using PIFs in geo-rectified images.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.151-151
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• 2020

표면영상유속측정법은 영상을 이용한 비접촉식 유속 측정 방법으로 카메라 외에 별도로 고가의 장비를 구매할 필요가 없을 뿐 아니라 현장 상황을 영상으로 확인할 수 있기 때문에 현장조사인력이 필요 없어 경제적이고, 안전하다는 장점을 갖고 있는 하천 유속 측정 방법이다. 표면영상유속측정법은 일반적으로 상호상관법을 이용하여 수표면을 촬영한 연속된 두 영상에서 입자군의 명암값 분포를 계산하여 입자군의 변위를 계산하고 이를 두 영상 사이의 시간 간격으로 나누어 입자군의 이동 속도를 산정하는 방법이다. 따라서 표면영상유속측정법으로 산정한 유속의 정확도를 높이기 위해서는 영상 내 두 입자군의 변위를 정확하게 계산하는 것이 무엇보다 중요하다. 즉, 분석하고자 하는 영상의 물리거리를 정확하게 계산할 수 있어야 한다. 카메라를 이용하여 실제 하천 영상을 촬영한 영상은 카메라 렌즈에 의한 왜곡이 필연적으로 발생하게 되고 이는 영상 내의 변위 산정 시에도 영향을 미친다. 특히 드론을 활용하여 넓은 하천 영역을 촬영할 경우 카메라 렌즈에 의한 왜곡은 실제 물리 변위 계산 정확도에 큰 영향을 미치게 된다. 이에 본 연구에서는 카메라 왜곡이 영상 내 변위 산정 결과의 정확도에 미치는 영향을 분석하였다. 연구 결과 카메라 렌즈 왜곡은 영상 중심에서 방사방향으로 점점 크게 발생하고 왜곡 정도는 비선형적으로 나타났으며, 변위 측정 오차는 영상의 중앙부에서는 거의 차이가 없었으며, 영상 외곽부에서 최대 오차가 발생하는 것으로 나타났다. 그리고 카메라 렌즈 왜곡 보정을 실시하게 되면 영상 전체적으로 변위측정 오차는 모두 제거할 수 있는 것으로 확인하였다. 따라서 카메라 렌즈 왜곡 보정을 실시하여 표면영상유속 측정 결과의 정확도를 개선할 수 있는 것으로 나타났다. 향후 카메라 렌즈 왜곡 보정을 실시한다면 하천의 표면유속을 보다 정확하게 측정할 수 있을 것으로 기대한다.