• 한국수학사학회지
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• 제21권1호
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• pp.121-138
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• 2008

본 논문에서는 입체도형에 대한 학습을 효과적으로 수행하기 위한 웹 기반 입체 도형 학습 프로그램을 설계하고 구현하였다. 이를 위해 학습자에게 편리한 사용자 인터페이스와 입체도형 학습에 필요한 기능을 분석하였으며, 학습자의 흥미를 유발 할 수 있는 다양한 입체도형 학습기능을 개발함으로써 실제 수업 현장에서 쓰일 수 있는 유용한 학습프로그램이 될 수 있도록 하였다. 기존 연구와의 비교분석과 초등학교 학생들의 사용 평가를 통해 본 프로그램의 유용함을 확인하였다.

• 제어로봇시스템학회논문지
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• 제7권3호
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• pp.255-262
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• 2001

According to the advancement of web related technologies, many works on robots using these technologies, called web-based robots enables sharing of expensive equipments as well as control of remote robots. But none of the existing methods about web-based robots in-clude robot simulators in their web browser, which transfer appropriate information of a remote place to the local users. In this paper, a web-based robot simulator is proposed and developed to control a remote robot by using the web. The proposed simulator can transfer the 3D information about the remote robot to the local users by using 3D graphics, which has not been previously developed. Also, it sends the camera image of a remote place to the local users so that the users can use this camera image as well as 3D information in order to control the remote robot.

• 한국전산구조공학회논문집
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• 제22권4호
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• pp.335-341
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• 2009

본 논문에서는 MLS기반 유한요소에 대한 현재 개발상황에 대한 개관과 향후 예상할 수 있는 응용분야에 대한 제안을 하였다. 이동최소제곱근사를 이용하여 형상함수를 생성하는 MLS기반 유한요소는, 요소의 경계에서 기존 유한요소의 성질-크로네커 델타 조건-을 가지면서도 기존 요소가 갖지 못했던 임의의 절점 추가가 자유롭다는 장점이 있어 다양한 변절점 요소로의 개발이 이루어져 왔다. 선형 또는 이차형상함수를 갖는 2차원 변절점요소 뿐 아니라, 균열선단과 균열면을 포함하고 있는 2차원 균열요소와 3차원에서의 제한적인 변절점요소 등이 개발되어 다양한 불연속성 문제에 적용 가능함이 입증되었다. 이러한 MLS기반 유한요소는 향후 2차원 변절점 3각요소, 2차원 삼각균열요소, 변절점 쉘요소, 균열 쉘요소, 마칭큐브알고리즘에 적합한 3차원 다면체요소로의 개발이 가능할 것으로 예상되며, 본 논문에서는 그 일례로 3차원 다면체요소를 이용한 대퇴골의 요소망 생성을 보였다.

• 전자공학회논문지B
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• 제32B권9호
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• pp.1171-1180
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• 1995

In this paper, we present a 3-D object recognition system in which the 3-D Hough transform domain is employed to represent the 3-D objects. In object modeling step, the features for recognition are extracted from the CAD models of objects to be recognized. Since the approach is based on the CAD models, the accuracy and flexibility are greatly improved. In matching stage, the sensed image is compared with the stored model, which is assumed to yield a distortion (location and orientation) in the 3-D Hough transform domain. The high dimensional (6-D) parameter space, which defines the distortion, is decomposed into the low dimensional space for an efficient recognition. At first we decompose the distortion parameter into the rotation parameter and the translation parameter, and the rotation parameter is further decomposed into the viewing direction and the rotational angle. Since we use the 3-D Hough transform domain of the input images directly, the sensitivity to the noise and the high computational complexity could be significantly alleviated. The results show that the proposed 3-D object recognition system provides a satisfactory performance on the real range images.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2175-2190
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• 2011

This paper presents the effects of depth map quantization for multiview intermediate image generation using depth image-based rendering (DIBR). DIBR synthesizes multiple virtual views of a 3D scene from a 2D image and its associated depth map. However, it needs precise depth information in order to generate reliable and accurate intermediate view images for use in multiview 3D display systems. Previous work has extensively studied the pre-processing of the depth map, but little is known about depth map quantization. In this paper, we conduct an experiment to estimate the depth map quantization that affords acceptable image quality to generate DIBR-based multiview intermediate images. The experiment uses computer-generated 3D scenes, in which the multiview images captured directly from the scene are compared to the multiview intermediate images constructed by DIBR with a number of quantized depth maps. The results showed that there was no significant effect on depth map quantization from 16-bit to 7-bit (and more specifically 96-scale) on DIBR. Hence, a depth map above 7-bit is needed to maintain sufficient image quality for a DIBR-based multiview 3D system.

• 한국콘텐츠학회논문지
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• 제18권9호
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• pp.710-721
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• 2018

본 연구에서는 오픈소스 SW인 Blender를 사용하여 인터넷에서 쉽게 구할 수 있는 3D 프린터용 STL(stereolithography) 파일 기반의 3D 애니메이션을 제작하는 방법을 제시하고 이를 OBJ(Object) 파일과 FBX(filmbox) 파일을 이용하는 경우와 비교하였다. STL 파일은 무료로 제공되는 장점이 있지만 OBJ나 FBX 파일과는 달리 계층 구조(hierarchy), 머티리얼(material) 및 텍스쳐(texture) 정보를 포함하지 않기 때문에 3D 애니메이션 제작과정이 좀 더 복잡해진다. 특히 계층구조 정보의 누락은 3D 애니메이션의 핵심인 리깅(rigging) 작업 시에 원하지 않는 부위가 움직이는 심각한 문제를 발생시키는 원인이 된다. 본 연구에서는 Blender의 웨이트 페인팅 기능을 이용하여 계층구조 누락으로 인한 문제를 해결할 수 있음을 예증하였으며 샘플링 횟수와 해상도가 렌더링(rendering) 시간에 미치는 영향도 함께 조사하였다. 한편 3D 프린터로 출력한 곤충 모형은 초등과학교육에서 새로운 형태의 교육 자료로 활용이 가능할 것으로 기대된다.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1436-1443
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• 2019

A fast gamma-ray dose rate assessment method for complex geometries based on stylized model reconstruction and point-kernel method is proposed in this paper. The complex three-dimensional (3D) geometries are imported as a 3DS format file from 3dsMax software with material and radiometric attributes. Based on 3D stylized model reconstruction of solid mesh, the 3D-geometrical solids are automatically converted into stylized models. In point-kernel calculation, the stylized source models are divided into point kernels and the mean free paths (mfp) are calculated by the intersections between shield stylized models and tracing ray. Compared with MCNP, the proposed method can implement complex 3D geometries visually, and the dose rate calculation is accurate and fast.

• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.186-191
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• 2016

This paper addresses the development of 3D data acquisition system (3D scanner) based laser structured-light image. The 3D scanner consists of a stripe laser generator, a conventional camera, and a rotation table. The stripe laser onto an object has distortion according to 3D shape of an object. By analyzing the distortion of the laser stripe in a camera image, the scanner obtains a group of 3D point data of the object. A simple semiconductor stripe laser diode is adopted instead of an expensive LCD projector for complex structured-light pattern. The camera has an optical filter to remove illumination noise and improve the performance of the distance measurement. Experimental results show the 3D data acquisition performance of the scanner with less than 0.2mm measurement error in 2 minutes. It is possible to reconstruct a 3D shape of an object and to reproduce the object by a commercially available 3D printer.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.115-119
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• 2020

Recently, CCTV installations are rapidly increasing in the public and private sectors to prevent various crimes. In accordance with the increasing number of CCTVs, video-based abnormal behavior detection in control systems is one of the key technologies for safety. This is because it is difficult for the surveillance personnel who control multiple CCTVs to manually monitor all abnormal behaviors in the video. In order to solve this problem, research to recognize abnormal behavior using deep learning is being actively conducted. In this paper, we propose a model for detecting abnormal behavior based on the deep learning model that is currently widely used. Based on the abnormal behavior video data provided by AI Hub, we performed a comparative experiment to detect anomalous behavior through violence learning and fainting in videos using 2D CNN-LSTM, 3D CNN, and I3D models. We hope that the experimental results of this abnormal behavior learning model will be helpful in developing intelligent CCTV.

• 한국CDE학회논문집
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• 제18권4호
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• pp.258-266
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• 2013

In shipbuilding, 2D manufacturing drawings are crucial for building a ship. Even various types of 3D models are being utilized for supporting ship manufacturing, which does not reduce the importance of 2D drawings. Recently things are changing in the shipbuilding industry. To reduce the number of 2D drawings or to reduce the quantity of information contained in 2D drawings, some attempts that can substitute for 2D drawings are being made. One of the attempts is to visualize lightweight 3D manufacturing models in a mobile device. In this paper, a method for displaying lightweight 3D models of a ship in an Android based device is introduced. To overcome the problem with parsing JT files in Android system, JT files are parsed in a Windows based server and as-simple-as-possible visualization data are transmitted to an Android based viewer. A comparison result with a commercial system is also given.