• Progress in Medical Physics
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• v.14 no.3
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• pp.151-160
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• 2003

The application of more complex radiotherapy techniques using multileaf collimation (MLC), such as 3D conformal radiation therapy and intensity-modulated radiation therapy (IMRT), has increased the significance of verifying leaf position and motion. Due to thier reliability and empirical robustness, quality assurance (QA) of MLC. However easy use and the ability to provide digital data of electronic portal imaging devices (EPIDs) have attracted attention to portal films as an alternatives to films for routine qualify assurance, despite concerns about their clinical feasibility, efficacy, and the cost to benefit ratio. In this study, we developed method for daily QA of MLC using electronic portal images (EPIs). EPID availability for routine QA was verified by comparing of the portal films, which were simultaneously obtained when radiation was delivered and known prescription input to MLC controller. Specially designed two-test patterns of dynamic MLC were applied for image acquisition. Quantitative off-line analysis using an edge detection algorithm enhanced the verification procedure as well as on-line qualitative visual assessment. In conclusion, the availability of EPI was enough for daily QA of MLC leaf position with the accuracy of portal films.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.1969-1977
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• 2010

James Cameron's "Avatar" has broken the national record of movie ticket sales, and it caused the boom of 3D and 3D related fields. This research is focused on the appropriate ways to embrace the stereoscopic 3D cinema and the assumable result in Korea. The new stereoscopic 3D is different from the old fashioned analogue 3D, and it has many possibilities that may influence Korean film industry. Since 1990s, the number of Korean film school has increased drastically, and many of those who graduated from the schools would experience fierce job market. 3D converting projects that require a lot of film majored personnels would solve the overly supplied film majored professionals. Through Korea's hundreds of film schools, when they include 3D filmmaking in their curriculum, they can train and educate 3D related staff such as stereographer, convergence puller, and depth continuity artists, and Korea can be an important 3D staff train center in the world. Educating 3D filmmaking can produce a noticeable result in terms of accepting 3D cinema. Stereoscopic 3D cinema has many possibilities in many fields not only in cinema but also almost every fields that related to the imagery. With government's supports, the investments from the 3D related corporations, and 3D education in colleges would be fast and efficient way to embrace and accept stereoscopic 3D cinema in Korea in terms of the size and the profit.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.225-229
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• 2006

햅틱 인터페이스 장치는 가상공간 상에서 얻어지는 시각적 효과와 더불어 힘(촉각)을 전달하여 사용자에게 현실감을 줄 수 있는 장치이다. 본 논문에서는 다양한 용도로 사용할 수 있는 2 차원 햅틱 인터페이스 장치를 설계 및 제작하고, 입체영상 시스템과 연동하여 오락실에서 흔히 볼 수 있는 에어하키 시스템을 가상현실 기술로 구현하였다. 이때 적절한 모델링과 햅틱 렌더링을 통하여 가상 에어하키 공을 칠 때 사용자가 핸들을 잡은 손으로 느끼는 충격과 반력을 2 차원 햅틱 인터페이스 장치를 통하여 느낄 수 있도록 하였다. 구현된 시스템의 시연을 통하여 공과 핸들의 충돌 시 공이 튕겨 나가는 방향과 속도가 실제와 유사하고 공과 핸들에서 충돌이 일어날 때 실제와 상당히 유사한 느낌은 얻을 수 있음을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.9 no.2
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• pp.27-32
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• 2004

If the areas existing in an object are composed of different color sets, the applicable object is segmented into independent areas so it gets to lose the meaning as an object. Therefore, it is required to selectively apply other information on the areas in addition to color information. Based on this methodology, this study, in addition to color information, has also analyzed the shape of isophotes that connect equivalence of brightness as a way of expressing cubic effect. And, through the analyzed information, it has judges independence or dependence of the areas, and then, proposed a way of object separation through significant regional matching of an object.

• Journal of Broadcast Engineering
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• v.14 no.1
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• pp.85-88
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• 2009

Recently "DMB Video-Associated Stereoscopic Data Services" standard has been published by TTA. The standard enables DMB broadcasters to provide 3D or stereoscopic interactive data services based on MPEG-4 BIFS (Binary Format for Scenes). The purpose is to entice viewers to utilize DMB interactive data services more often by providing realistic and protrusive image objects overlaid on top of the main video in the background. This paper provides the background, technical analysis, and in-depth considerations for the standard. Also the results of standard verification are provided including the results of interoperability test with the existing terrestrial DMB receivers.

• Journal of Korean Society for Geospatial Information Science
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• v.6 no.2 s.12
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• pp.11-20
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• 1998

Although aerial photogrammetry has been used to generate or update digital maps. It is difficult to make the spatial and attribute data for all kinds of objects on the ground with only aerial photogrammetry. Therefore, we are getting informations of the object on the ground through an on-the-spot survey In order to improve accuracy and reliability of on-the-spot survey in this study, we obtained stereo images from high resolution digital camera (1152*864 pixels) and developed the video photogrammetry which was able to determine the three dimensional coordinates from stereo images by applying DLT(Direct Linear Transformation). Also, the developed video photogrammetry could generate and update the spatial and attribute data in digital maps by using a function that could connect three dimensional coordinates with the attribute data.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.199-210
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• 1998

In this paper, we present a 3D reconstruction method of color volume data for a computerized human atlas. Binary volume rendering which takes the advantages of object-order ray traversal and run-length encoding visualizes 3D organs at an interactive speed in a general PC without the help of specific hardwares. This rendering method improves the rendering speed by simplifying the determination of the pixel value of an intermediate depth image and applying newly developed normal vector calculation method. Moreover, we describe the 3D boundary encoding that reduces the involved data considerably without the penalty of image quality. The interactive speed of the binary rendering and the storage efficiency of 3D boundary encoding will accelerate the development of the PC-based human atlas.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.72-82
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• 2009

Objective: The purpose of this study was to investigate the structural changes of the hyoid bone and upper airway after orthognathic surgery for skeletal class III anterior open bite patients, and make comparisons with normal occlusion. Methods: Pre- and post-operative computed tomography (CT) examinations were performed on 12 skeletal class III anterior open bite patients who were treated with mandibular setback osteotomy. Using the V-works $4.0^{TM}$ program, 3-dimensional images of the total skull, mandible, hyoid bone, and upper airway were evaluated. Results: In the Class III open bite group, the hyoid bone were all positioned anteriorly, compared to the Normal group (p < 0.05). The angle between the hyoid plane and mandibular plane in the Class III openbite group before surgery was greater than in the Normal group (p < 0.05), and the difference increased after surgery (p < 0.01). In the Class III openbite group, the volume of the upper airway decreased after surgery (p < 0.001) and the volume of the upper airway was smaller than the Normal group before and after surgery (p < 0.001). Conclusions: The narrow upper airway space in skeletal Class III openbite patients decreased after mandibular setback osteotomy. This may affect the post-surgical stability.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.358-370
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• 2008

Objective: The purpose of this study was to investigate the horizontal skeletal pattern and dental arch differences between Class III malocclusion patients and normal occlusion patients. Methods: Twenty skeletal Class III malocclusion patients and ten normal occlusion patients were selected and 3D facial CT were taken to analyze the horizontal skeletal differences between the two groups. Results: In the horizontal comparison of the maxilla, skeletal width and perimeter were significantly smaller in skeletal Class III patients on ANS and A point reference planes. The difference between maxillary width of ANS and A point reference planes showed that there was greater constriction of the first and second premolar in skeletal Class III patients. In the horizontal comparison of the mandible, the widths of the canine and premolar area were significantly larger in skeletal Class III patients on B point reference plane. The differences between width of the upper and lower jaws (comparison of A and B reference planes) were significantly large in the canine and premolar area. Conclusions: From this study, the characteristics of Class III malocclusion patients were shown through horizontal constriction of the maxilla. But to make clear further detailed characteristics of Class III malocclusion patients, additional studies are necessary.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.471-482
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• 2011

This paper introduces an development of high-definition(HD) 3DTV experimental broadcasting system and its experimental service that has been launched via three broadcasting network including terrestrial, cable and satellite in the late of 2010. This 3DTV experimental broadcasting service employs an innovative 3DTV broadcasting mechanism, called as dual stream method in which left and right images are encoded by using each video encoder and multiplexed using MPEG-2 system technology for guaranteeing backward-compatibility with legacy DTV. This paper specifically describes the developed experimental broadcasting system, concentrating on 3DTV re-multiplexer and 3DTV receiver. Finally, implementation and terrestrial 3DTV experimental broadcasting service results will be introduced from the point of objective and subjective evaluation.