• Current Optics and Photonics
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• 제4권4호
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• pp.277-285
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• 2020

Computer-generated holograms (CGH) are the core devices to solve the problem of freeform surface measurement. In view of the overlay error introduced in the manufacturing process of CGH, this paper proposes an evaluation model for analyzing the overlay error of CGH. The detection method of extracting CGH profile information by an ultra-depth of field micro-measurement system is presented. Furthermore, based on the detection method and technical scheme, the effect of overlay error on the wavefront accuracy of CGH can be evaluated.

• 대한치과의사협회지
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• 제54권7호
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• pp.563-574
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• 2016

A clear overlay appliance is a type of a removable appliance made from transparent thermoplastic plastic film that covers the entire dentition to move the teeth. It is one of the most favored orthodontic methods opted for by adult patients; this treatment is esthetic, does not cause discomfort and allows oral hygiene to be easily managed when compared to other conventional fixed treatment methods. However, the use of clear overlay appliances, such as invisalign or clear aligner, is associated with various clinical challenges. In particular, the appliances require longer treatment periods compared to fixed treatment, and due to the structural characteristics of the appliances, it is difficult to make proper posterior occlusion and certain type of tooth movement, including extrusion, rotation and tip. Thus, the clear overlay appliances are regarded as supplementary appliances by most orthodontists and have been used for simple orthodontic treatments, such as partial anterior alignments or orthodontic relapse cases. Owing to the remarkable advancement in the field of 3D digital technology over a period of 15 years, the accuracy and convenience of modern clear overlay appliances have continuously improved. Moreover, orthodontic outcomes have also been greatly improved by the introduction of new materials and successful application of various biomechanical methods from conventional orthodontic treatments in the design of clear overlay appliances. This study investigates the clinical limitations that should be considered during the application of clear overlay appliances and also examines the efforts and methods used to overcome these challenges.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2012년도 한국컴퓨터종합학술대회논문집 Vol.39 No.1(D)
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• pp.190-192
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• 2012

In this paper, we present theoretical queuing analysis for hybrid overlay/underlay Cognitive Radio (CR) system by applying M/M/1 queuing model where the rate of arrival and the service capacity are subject to Poisson alterations. Numerical results are used to prove a high degree of accuracy for the derived expressions. The result can be used as a benchmark to evaluate the performance of a hybrid overlay/underlay CR system.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.476-478
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• 2015

This paper deals with synthesis of 4 bar linkage by using optimum design. To design 4 bar linkage, overlay method is proposed and for optimization, genetic algorithm is applied with objective function. The accuracy of this method will be determined by errors between real value and test value. We will use Chebychev spacing to get 3 precision positions of input angles. The output angles will be determined by the function that the designer wants input and output relations to be. It will be applied to example to show the accuracy of this method. The advantages of using this method are that it is fast to get optimal solution and it is simple to use.

• 방송공학회논문지
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• 제21권3호
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• pp.307-318
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• 2016

Overlay texts are artificially superimposed on the broadcasting videos by human producers. These texts provide additional information to the audiovisual content. Especially, the overlay texts in news video contain concise and direct description of the content. Therefore, it is most reliable clue for constructing a news video indexing system. To make this indexing system in the TV news program, it is important to detect and recognize the texts. This paper proposes the identification of the overlay text beginning frame to help the detection and recognition of the overlay text in news videos. Since all frames in the video sequences do not contain the overlay texts, the overlay text extraction from every frame is unnecessary and time-wasting. Therefore, to focus on only the frame containing the overlay text can be enhanced the accuracy of the overlay text detection. The comparative experiments of the text beginning frame identification methods were carried out with respect to Korean television news videos. Then the appropriate processing method is proposed.

• 한국도로학회논문집
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• 제19권5호
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• pp.49-58
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• 2017

PURPOSES : The objective of this study is to develop a simple regression model in designing the asphalt concrete (AC) overlay thickness using the Mechanistic-empirical pavement design guide (MEPDG) program. METHODS : To establish the AC overlay design equation, multiple regression analyses were performed based on the synthetic database for AC thickness design, which was generated using the MEPDG program. The climate in Seoul city, a modified Hirsh model for determining dynamic modulus of asphalt material, and a new damaged master curve approach were used in this study. Meanwhile, the proposed rutting model developed in Seoul city was then used to calibrate the rutting model in the MEPDG program. The AC overlay design equation is a function of the total AC thickness, the ratio of AC overlay thickness and existing AC thickness, the ratio of existing AC modulus and AC overlay modulus, the subgrade condition, and the annual average daily truck traffic (AADTT). RESULTS : The regression model was verified by comparing the predicted AC thickness, the AADTT from the model and the MEPDG. The regression model shows a correlation coefficient of 0.98 in determining the AC thickness and 0.97 in determining AADTT. In addition, the data in Seoul city was used to validate the regression model. The result shows that correlation coefficient between the predicted and measured AADTT is 0.64. This indicates that the current model is more accuracy than the previous study which showed a correlation coefficient of 0.427. CONCLUSIONS:The high correlation coefficient values indicate that the regression equations can predict the AC thickness accurately.

• 한국CDE학회지
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• 제21권2호
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• pp.31-33
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• 2015

This paper deals with synthesis of 4 bar linkage by using optimum design. To design 4 bar linkage, overlay method is proposed and for optimization, genetic algorithm is applied with objective function. The accuracy of this method will be determined by errors between real value and test value. We will use Chebychev spacing to get 3 precision positions of input angles. The output angles will be determined by the function that the designer wants input and output relations to be. It will be applied to example to show the accuracy of this method. The advantages of using this method are that it is fast to get optimal solution and it is simple to use.

• 대한공간정보학회지
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• 제19권3호
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• pp.49-56
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• 2011

도시 지역의 환경은 빠르게 변화하고 있기 때문에 그 변화를 신속하게 탐지하여 수치지도 데이터베이스에 반영하는 것이 필요하다. 이에 LiDAR 자료를 사용하여 도시지역 건물의 변화를 탐지하려는 연구가 진행되고 있다. 본 연구에서는 LiDAR 자료와 기존 수치지도를 이용하여 객체 기반으로 건물변화를 탐지하고 그 유형을 분류하고자 하였다. 점 기반으로 건물의 외곽선을 추출하고 수치지도 건물 레이어와 중첩하여 중첩비교와 형상비교를 통해 변화유형을 분류하였다. 중첩비교시 객체별 적응적 임계치를 산정하여 적용함으로써 변화탐지의 객관성과 정확도를 높이고자 하였다. 실험결과, 제안한 방법으로 도시지역 건물의 변화를 탐지하고 분류하는 것이 기존 방법에 비해 높은 분류 정확도를 보임을 확인하였다.

• 대한공간정보학회지
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• 제7권2호
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• pp.57-68
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• 1999

지형정보의 활용을 위한 기본도 구축은 효율적인 GIS 작업의 성공여부를 좌우할 만큼 매우 중요한 의미를 지니고 있다. 그러므로, 실용적인 기본도 제작을 위해서는 국가지리정보체계와 필지중심토지정보체계를 일원화할 수 있는 지형 및 지적정보의 연계 활용이 이루어져야 한다. 본 연구에서는 1:5,000 항공사진을 이용하여 정사투영 영상지도를 제작하고 map revision을 수행하였다. 그리고 이를 이용하여 기본도를 제작하고 지형 및 지적정보의 중첩정확도를 비교 분석함으로써, 영상지도와 지적정보를 중첩한 통합 데이터베이스의 제공은 물론 정확한 토지현황 파악과 환경 및 도시계획분야에 그 활용 방안을 제시할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.597-600
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• 2003

The development and maintenance of a sound bond are an essential requirements of concrete repair and replacement. The bond property of a bonded overlay to its substrate concrete during the lifetime is one of the most important performance requirements which should be quantified. A standard or a verified bond strength measurement method is required at field for screening, selecting materials and quality control for overlay or repair materials. This study compares the nipple pipe direct tensile test, flexural adhesion test, and core pull-off test with their test results. Substantial differences in the failure stresses of three test methods were attributed to their different geometries and loading conditions. From these comparison and investigation, core pull-off test was relatively good because the coefficient of variation values were about 2%. It would be suitable for use in-situ because of its simplicity and accuracy.