• The Journal of Korean Society for Radiation Therapy
• /
• v.32
• /
• pp.85-92
• /
• 2020

Purpose: To find out the advantages of thermoplastic bolus compared to conventional bolus, which is mainly used in clinical practice, We evaluated Two cases in terms of dose and location reproducibility to assess Usability of thermoplastic Bolus for skin VMAT radiotherapy. Materials and Methods: Two patient's treated with left breast skin lesion were simulated using thermoplastic Bolus and planned with 2arc VMAT. the prescription dose was irradiated to 95% or more of the target volume. We evaluated The reproducibility of the bolus position by measuring the length of the air gap in the CBCT (Cone Beam CT) image. to evaluate dose reproducibility, we compared The dose distribution in the plan and CBCT and measured in vivo for patient 2. Results: The difference between the air gap in patient 1's simulation CT and the mean air gap (M1) during 10 treatments in the CBCT image was -0.42±1.24mm. In patient 2, the difference between the average air gap between the skin and the bolus (M2) during 14 treatments was -1.08±1.3mm, and the air gap between the bolus (M3) was 0.49±1.16. The difference in the dose distribution between Plan CT and CBCT was -1.38% for PTV1 D95 and 0.39% for SKIN (max) in patient 1. In patient 2, PTV1 D95 showed a difference of 0.63% and SKIN (max) -0.53%. The in vivo measurement showed a difference of -1.47% from the planned dose. Conclusion: thermoplastic Bolus is simpler and takes less time to manufacture compared to those produced by 3D printer. Also compared to conventional bolus, it has high reproducibility in the set-up side and stable results in terms of dose delivery.

• The KIPS Transactions:PartD
• /
• v.13D no.3 s.106
• /
• pp.391-398
• /
• 2006

This paper verifies deployment algorithms in wireless sensor networks using SPIN, a widely used model checking tool. In this paper, two deployment algorithms, DSSA(Distributed Self Spreading Algorithm) and TBDA(Tree Based Deployment Algorithm), are verified to check their stability against oscillation as well as energy consumption that is an important factor in wireless sensor networks.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.361-362
• /
• 2019

조선시대 반차도는 왕실 행차에 관한 배열을 나타낸 시각자료이다. 반차도는 구성요소를 평면적이고 간략하게 표현했기 때문에 전문적인 지식이 없는 일반 관람객이 왕실 행차의 내용을 파악하기는 쉽지 않았다. 기존 왕실 행차와 관련된 콘텐츠는 모니터 상에서 2D 이미지를 애니메이션으로 상영하거나 간단한 조작을 통해 3D 콘텐츠를 감상하는 방식으로 재현되었다. 그러나 공간적으로 한정된 모니터를 통해 관람해야 했기 때문에 행렬의 전체적인 모습을 충분히 전달하지 못하는 단점이 있었다. 본 논문에서는 3D 객체를 반차도에 직접 증강시킴으로써 기존 콘텐츠의 문제를 극복하고 왕실 행차에 관한 정확하고 구체적인 이미지를 전달하고자 한다. 이 연구를 통해 관람객에게 문화유산에 관한 높은 품질의 경험을 제공할 수 있을 것으로 기대한다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.255-255
• /
• 2015

지진해일은 주기가 긴 파랑으로 방파제나 방호구조물에 의한 에너지 감소가 작은 특성이 있다. 또한, 범람구역의 구조물 밀집도 및 지형적 요인에 따라 범람영역, 침수심, 파력 등이 상이하게 나타나므로 유체흐름의 입체적 변화양상을 고려하여야 한다. 본 수리모형실험은 임원항을 대상으로 구조물에 작용하는 지진해일의 파력특성을 3차원수리모형실험을 통해 검토하고, 파력산정계수(${\alpha}$)를 제시한다. 3차원 수리모형실험은 1983년 동해 중부 지진해일 발생 시 국내에서 가장 큰 피해를 입은 임원항을 대상으로 배후부지의 구조물과 인근 해안의 지형을 1/100으로 재현하여 실험에 임하였다. 입사파랑은 고립파(solitary wave)로 재현하였으며, 천수(shoaling)에 의한 파고변화를 측정하고 그에 따른 배후부지의 침수심, 구조물에 작용하는 파력을 측정하였다. 분석된 파력 산정계수(${\alpha}$)는 임원항 인근 해역 및 배후부지의 방재대책 수립을 위한 기초자료로 활용될 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.3
• /
• pp.859-871
• /
• 2014

In order to analyze the density current due to salt and temperature difference, this study develops new numerical model (LES-WASS-3D ver. 2.0) by introducing state equation for salt and temperature and 3D advection-diffusion equation to existing 3D numerical wave tank (LES-WASS-3D ver. 1.0). To verify the applicability, the newly-developed numerical model is analyzed comparing to the experimental result of existing numerical model. In the result, it well implement the behavior and vertical salt concentration of advected and diffused seawater as well as flow velocity and temperature of the discharged warm water. This confirms the validity and effectiveness of the developed numerical model.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.233-233
• /
• 2019

본 연구에서는 3형식 다공성 인공어초의 국부세굴 발생에 따른 인공어초의 안정성 검토를 위하여 3차원 수치모형인 FLOW-3D의 Sediment 모듈을 적용하여 분석을 실시하였다. 실험파랑 설정을 위하여 인공어초 설치 예정지인 서해 대상해역(대청도, 연평도 인근)의 100년 빈도 설계파랑을 적용하였으며, Bretschneider-Mitsuyasu 스펙트럼 기법을 통하여 파랑을 재현하였다. 원형상격자 조건은 최대 0.1m~2.0m에 해당하며, 수치모형실험 해석 시간을 고려하여 입사파랑의 진행방향으로 인공어초의 1/2 폭에 해당하는 X축(190개), Y축(80개), Z축(110~180개) 영역에 대한 격자조건 설정하고 분석을 실시하였다. 분석은 인공어초 하중에 따른 동적 거동을 반영하는 FSI(Flood Structure Interaction)기법을 적용하였으며, 분석결과 인공어초 구조물 하단의 돌출부분에서 세굴발생이 확인되었으며, 최대세굴심은 3형식 인공어초의 규격 및 단위체적당 중량이 클수록 높게 발생하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• fall
• /
• pp.193-196
• /
• 2021

홀로그램(Hologram)은 3차원 물체에서 나오는 빛의 정보를 제어하는 기술이다. 현재는 컴퓨터 생성 홀로그램(CGH)으로 생성한 디지털 홀로그램에 관한 연구, 특히 물체에서 나오는 빛의 정보를 최대한 기록하고 재현하여 디지털 홀로그램의 해상도를 향상 시키려는 연구가 활발히 진행되고 있다. 이에 본 논문에서는 고해상도 홀로그램 영상을 얻기 위해 딥러닝 기반 초해상도(Super Resolution) 네트워크를 훈련 및 최적화하여, 저해상도 위상 홀로그램 영상으로부터 높은 화질의 홀로그램 영상을 재현하는 고해상도 위상 홀로그램 영상을 생성하는 것을 목표로 한다. 이때 위상 홀로그램 영상의 특성을 이용한 순환 손실 함수(Circular loss function)를 새롭게 제안하며, 기존의 이미지 초해상도 신경망 모델을 학습시킬 때 자주 사용하는 L1 손실 함수와 비교했을 때 약 0.13dB 정도의 성능 향상이 있었다.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.8
• /
• pp.23-32
• /
• 2024

NVS (Novel View Synthesis) is a field in computer vision that reconstructs new views of a scene from a set of input views. Real-time rendering and high performance are essential for NVS technology to be effectively utilized in various applications. Recently, 3D-GS (3D Gaussian Splatting) has gained popularity due to its faster training and inference times compared to those of NeRF (Neural Radiance Fields)-based methodologies. However, since 3D-GS reconstructs a 3D (Three-Dimensional) scene by splitting and cloning (Density Control) Gaussian points, the number of Gaussian points continuously increases, causing the model to become heavier as training progresses. To address this issue, we propose two methodologies: 1) Gaussian blending, an improved density control methodology that removes unnecessary Gaussian points, and 2) a performance enhancement methodology using a depth estimation model to minimize the loss in representation caused by the blending of Gaussian points. Experiments on the Tanks and Temples Dataset show that the proposed methodologies reduce the number of Gaussian points by up to 4% while maintaining performance.

• 한국공간정보시스템학회:학술대회논문집
• /
• 2005.11a
• /
• pp.29-34
• /
• 2005

Aerial photogrammetry, which is one of the most frequent used technology in mapping and surveying, has been appreciated for its work flow and accuracy to generate 2D and 3D geospatial data. In aerial photograrnrnetry, more than two photographs are taken over the same target area in different position with overlap. Using these photographs and minimum number of ground control points, 3D stereo model is so formed that the ground surface in reality is reconstructed through analogue/analytical plotter or digital photogrammetry system. In case of digital photogrammetry system, 3D geospatial data could be automatically extracted in partial. Recently, in the advent of aerial digital camera such as ADS40 and DMC, digital photogrammetry system will be in the frist place for generating 3D geospatial data. In this paper, we experimentally generated 3D geospatial data using digital photograrnrnetry system in the aspect of work flow.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.12
• /
• pp.115-125
• /
• 2003

The design methodology of plastic injection molding die has been gradually moved from two-dimensional line drawings to three-dimensional solid models. The 3D design gives many benefits, a few of which are: ease of design change, data associativity from concept design to final assembly. In the paper represented is the implementation of a program which automatically generates 3D mold-bases and cooling-lines, conforming to given geometric constraints. It utilized a commercial CAD software and the related API(application program interface) libraries. We constructed a DB(database) of typical mold-bases assembled from standard parts, from which the geometry (position & dimension) of a mold-base and composed parts can be automatical]y determined by a few key parameters. Also we classified cooling lines into several typical types and constructed a DB, from which the position of cooling lines is automatically determined. The research is expected not only to simplify construction of a 3D mold-base model including cooling lines but also to reduce design efforts, by way of databases and automatized determination of geometric dimensions.