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위치 기반 삼각화를 이용한 입자 기반 유체 시뮬레이션 가속화 기법
홍만기(Manki Hong),임재호(Jaeho Im),김창헌(Chang-Hun Kim),변혜원(Hae Won Byun) 한국컴퓨터그래픽스학회 2017 컴퓨터그래픽스학회논문지 Vol.23 No.1
본 논문은 입자 기반 대규모 유체 시뮬레이션의 가속화 기법을 새롭게 제안한다. 전통적인 입자 기반 유체 시뮬레이션은 SPH(Smoothed Particle Hydrodynamics)기법[1]을 통해 인접 입자와 물리량을 상호작용하는 방식으로 이루어졌다. 이러한 방식은 잔잔한 표면이나 유체 내부와 같이 입자의 움직임이 적은 부분에서는 연산량에 비해 가시적인 변화를 보이지 않는다는 특성이 있다. 이러한 현상은 입자의 개수가 많아질수록 두드러지게 나타난다. 기존 연구에서는 유체의 각 부분을 적응적으로 나눔으로써 낭비되는 연산량을 줄이려는 시도를 했다. 본 논문은 대규모 시뮬레이션에 적합한 입자 기반 유체시뮬레이션 기법을 제안한다. 시뮬레이션에서 사용되는 모든 입자를 유체 움직임의 기준이 되는 샘플링 입자와 샘플링 입자에 의해 움직임이 결정되는 보간 입자로 분류하고 샘플링 입자에 의해 생성되는 삼각형 맵과 무게중심 좌표계를 이용한 보간방법을 통해 연산시간을 단축하는 기법을 제안한다. 우리의 기법은 입자의 개수가 많을수록 더욱 효율적이며 유체 표면의 세밀한 움직임 또한 표현하는 것이 가능하다. This paper proposes a novel acceleration method for particle based large scale fluid simulation. Traditional particle-based fluid simulation has been implemented by interacting with physical quantities of neighbor particles through the Smoothed Particle Hydrodynamics(SPH) technique[1]. SPH method has the characteristic that there is no visible change compared to the computation amount in a part where the particle movement is small, such as a calm surface or inter-fluid. This becomes more prominent as the number of particles increases. Previous work has attempted to reduce the amount of spare computation by adaptively dividing each part of the fluid. In this paper, we propose a technique to calculate the motion of the entire particles by using the physical quantities of the near sampled particles by sampling the particles inside the fluid at regular intervals and using them as reference points of the fluid motion. We propose a technique to adaptively generate a triangle map based on the position of the sampled particles in order to efficiently search for nearby particles, and we have been able to interpolate the physical quantities of particles using the barycentric coordinate system. The proposed acceleration technique does not perform any additional correction for two classes of fluid particles. Our technique shows a large improvement in speed as the number of particles increases. The proposed technique also does not interfere with the fine movement of the fluid surface particles.
정한신(Han Sin Jeong),손영익(Young Ik Son),정만기(Man ki Chung),민진영(Jin Young Min),오재원(Jae Won Oh),홍상덕(Sang Duk Hong),이현석(Hyun Seok Lee),백정환(Chung Hwan Baek) 대한두경부종양학회 2006 대한두경부 종양학회지 Vol.22 No.1
Background and Objectives: Maxillectomy is the mainstay of treatment for malignant tumors of the maxillary sinus(MS). Nevertheless, few have been reported on the surgical outcomes of maxillectomy for malignant tumors of MS in Korean literature. Based on our clinical experience, the authors aimed to present the treatment outcomes of maxillectomy for squamous cell carcinomas(SCC) of MS. Subjects and Methods: We reviewed the medical records of 26 cases of maxillectomies with see of MS, who were treated from 1995 to 2004 at Samsung Medical Center. Most patients(73.1%) were locally advanced stage(T3 or T4a) at initial presentation. Total maxillectomy was performed in 18 cases, which is the most frequent procedure(69.2%). We analyzed the treatment outcomes of see of MS and several variables includeing tumor stage and resection margin to identify predictors for treatment failure after maxillectomy. Follow-up duration ranged from 7 to 89 months with a mean of 33 months. Results: Treatment failure occurred in 7 cases(26.9%), among which 3 were salvaged. Three of 26 maxillectomies(11.5%) showed the positive or close(less than 5mm) resection margin in their posterior resection sites; however it did not coincide with the site of recurrence after radiation therapy. Among patients who had been followed up for more than 6 months, disease-free 3 year survival rate was 100.0% in T1 and T2, 76.2% in T3, 60% in T4a, and 69.6% in total. Conclusion: Even though most of see of MS were detected at locally advanced stage, maxillectomy with or without postoperative radiation therapy for resectable MS see(T1-T4a) provided the acceptable treatment outcome(70%, 3Y disease-free survival rate).