• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1722-1729
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• 2006

Predicting the mechanical properties of the 3-D scaffold using finite element method (FEM) simulation is important to the practical application of tissue engineering. However, the porous structure of the scaffold complicates computer simulations, and calculating scaffold models at the pore level is time-consuming. In some cases, the demands of the procedure are too high for a computer to run the standard code. To address this problem, the representative volume element (RVE) theory was introduced, but studies on RVE modeling applied to the 3-D scaffold model have not been focused. In this paper, we propose an improved FEM-based RVE modeling strategy to better predict the mechanical properties of the scaffold prior to fabrication. To improve the precision of RVE modeling, we evaluated various RVE models of newly designed 3-D scaffolds using FEM simulation. The scaffolds were then constructed using microstereolithography technology, and their mechanical properties were measured for comparison.

• 한국통신학회논문지
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• 제41권11호
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• pp.1557-1565
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• 2016

인간이 개입하지 않는 UAV 시스템은 다양한 행동을 자율적으로 수행하여 임무를 달성해야하는 어려움이 있다. 그러나 인간이 개입하지 않는 환경에서의 실제 실험은 많은 위험과 비용이 발생한다. 따라서 실제 환경 실험에 앞서 시뮬레이션 실험을 통한 검증이 필요함은 자명하다. 본 논문에서는 에이전트 기반 자율 UAV의 실험을 위한 3차원 가상환경과 이산사건 시뮬레이션 환경 구축하고 연동한 시스템을 제안한다. 재난 상황에서의 UAV 3기를 이용한 구조임무 시뮬레이션을 통해 그 유효성을 검증 하였다.

• 한국화재소방학회논문지
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• 제25권6호
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• pp.156-167
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• 2011

최근 건물의 대형화, 고층화, 복잡화가 이루어지고 있으며, 건축물 화재 발생건수와 이로 인한 인명 및 재산 피해의 증가함에 따라 화재피난 시뮬레이션을 통한 건축물의 안전성 점검의 필요성이 대두되고 있다. 따라서 본 연구에서는 외산 프로그램에 의존하고 있는 화재피난 시뮬레이션 분야에 한국인의 특성을 고려한 시뮬레이션 시스템을 구현하고자 하였다. 그 결과 3차원 공간 정보 기반으로 공간의 토폴로지를 생성하고, 피난 경로를 탐색하는 화재피난 시뮬레이션을 구축하였다.

• 한국정보통신학회논문지
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• 제19권1호
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• pp.119-126
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• 2015

본 논문에서는 항만컨테이너 운영 모니터링 및 계획 시뮬레이션의 결과를 3차원으로 정적 동적 개체를 포함하는 주변 환경의 거동을 시각적으로 표현하고 실제 작업이 이루어지는 애니메이션을 통해 운영모델을 직관적으로 평가가 가능한 시뮬레이션 가시화 시스템을 제안한다. 제안한 항만 시뮬레이션 가시화 시스템(PSVS)은 객체의 상태를 XML기반으로 설계하여 기존의 항만 운영 시뮬레이션(CATOS)과 상호운용성에 있어서 연동성을 극대화하고 실시간으로 대규모 객체에 대한 애니메이션 표현이 가능하도록 구현하였다. 본 논문에서는 PSVS시스템의 설계 방법에 대해서 설명하고 실험을 통해 PSVS의 타당성을 검토하였다.

• 한국컴퓨터정보학회논문지
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• 제24권2호
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• pp.75-84
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• 2019

The purpose of this study was to present a good pants pattern for boys aged 13-18 by comparing and analyzing the pants pattern according to lower body shape. And through it, this study was to provide basic data for pants production considering male student body shape. The pattern of this study used the industrial type Lee Hee-chun pattern and DC Suite Program for 3D virtual simulation. As a result of the appearance evaluation, there was a significant difference between the patterns in most items. Type 2 was rated highly, followed by Type 4, Type 3, and Type 1. Type 1 required correction of the length of the pants and the amount of crotch part, while type 3 required adjustment of the pants in the knee area. Type 4 required correction of pattern drawing method of crotch width, thigh circumference, and knee circumference. This pattern method was evaluated as suitable for slender body shape. This study suggests a pants pattern system suitable for adolescent boys by reflecting the body shape characteristics of adolescent boy with a change of body shape. It is expected that this will meet the increasing demand for fitting. In this study, we have examined 3D virtual simulation, not actual wear experiment, so it will be necessary to investigate the difference through actual clothing experiment for adolescent boys.

• Structural Monitoring and Maintenance
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• 제9권3호
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• pp.237-258
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• 2022

This paper studies detecting and locating loose bolts using nonlinear guided waves. The 3D Finite Element (FE) simulation is used for the prediction of guided waves' interactions with loose bolted joints. The numerical results are verified by experimentally obtained data. The study considers bolted joints consisting of two bolts. It is shown that the guided waves' interaction with surfaces of a loose bolted joint generates Contact Acoustic Nonlinearity (CAN). The study uses CAN for detecting and locating loose bolts. The processed experimentally obtained data show that the CAN is able to successfully detect and locate loose bolted joints. A 3D FE simulation scheme is developed and validated by experimentally obtained data. It is shown that FE can predict the propagation of guided waves in loose bolts and is also able to detect and locate them. Several numerical case studies with various bolt sizes are created and studied using the validated 3D FE simulation approach. It is shown that the FE simulation modeling approach and the signal processing scheme used in the current study are able to detect and locate the loose bolts in imperfect bolted joints. The outcomes of this research can provide better insights into understanding the interaction of guided waves with loose bolts. The results can also enhance the maintenance and repair of imperfect joints using the nonlinear guided waves technique.

• Ocean Systems Engineering
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• 제7권3호
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• pp.195-223
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• 2017

This paper presents 3D numerical simulations of a Free Standing Hybrid Riser under Vortex Induced Vibration, with prescribed motion on the top to replace the motion of the buoyancy can. The model is calculated using a fully implicit discretization scheme. The flow field around the riser is computed by solving the Navier-Stokes equations numerically. The fluid domain is discretized using the overset grid approach. Grid points in near-wall regions of riser are of high resolution, while far field flow is in relatively coarse grid. Fluid-structure interaction is accomplished by communication between fluid solver and riser motion solver. Simulation is based on previous experimental data. Two cases are studied with different current speeds, where the motion of the buoyancy can is approximated to a 'banana' shape. A fully three-dimensional CFD approach for VIV simulation for a top side moving Riser has been presented. This paper also presents a simulation of a riser connected to a platform under harmonic regular waves.

• Journal of International Society for Simulation Surgery
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• 제3권1호
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• pp.12-15
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• 2016

Functional and esthetic reconstruction after segmental mandibulectomy is one of the most challenging surgeries in microsurgical reconstruction field. Simulation surgery before free flap reconstruction has been performed for efficient surgery and successful results. Fibula free flap is the flap of the choice for reconstruction of the segmental mandibular defect. Straight nature of the fibula bone requires multiple segmentations to fit into mandible. 3D rapid prototype (RP) model gives a lot of information for mandibular reconstruction. The purpose of this study was to report mandibular reconstruction with free fibular flap using simulation surgery. A total of 30 consecutive patients were included for functional and esthetic evaluation. Among 30 patients, two flaps showed necrosis after radiotherapy. The other flaps were all survived and showed successful reconstruction in both function and esthetics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.4120-4132
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• 2017

In this research, we implement a deformable object simulation system using OpenGL's shader language, GLSL4.3. Deformable object simulation is implemented by using volumetric mass-spring system suitable for real-time simulation among the methods of deformable object simulation. The compute shader in GLSL 4.3 which helps to access the GPU resources, is used to parallelize the operations of existing deformable object simulation systems. The proposed system is implemented using a compute shader for parallel processing and it includes a bounding box-based collision detection solution. In general, the collision detection is one of severe computing bottlenecks in simulation of multiple deformable objects. In order to validate an efficiency of the system, we performed the experiments using the 3D volumetric objects. We compared the performance of multiple deformable object simulations between CPU and GPU to analyze the effectiveness of parallel processing using GLSL. Moreover, we measured the computation time of bounding box-based collision detection to show that collision detection can be processed in real-time. The experiments using 3D volumetric models with 10K faces showed the GPU-based parallel simulation improves performance by 98% over the CPU-based simulation, and the overall steps including collision detection and rendering could be processed in real-time frame rate of 218.11 FPS.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2005년도 추계학술대회 및 정기총회
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• pp.84-90
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• 2005

본 연구는 임의의 지역을 선정하여 그 지역의 환경 색채를 분석한 후 NCS색체계와 히스토그래밍을 이용하여 주조색, 보조색, 강조색을 추출한 후 그 지역의 특성에 맞는 배색코드들을 제안한다. 이를 위해 색채조화론에 근거한 Color Dictionary를 제작하였으며 특정 지역을 3D모델링 한 최적의 배색 코드를 추출하여 주변 환경과 잘 어울리는 색채 시뮬레이션을 제시하고 Web3D 표준기술을 이용하여 상호작용과 다양한 뷰포인트에서 시연할 수 있는 프로그램 환경을 구축하였다. 이에 따른 기대효과는 첫째, 국가 홍보에 있어서 경쟁력 제고를 위한 효과. 둘째, 도시환경 색채계획의 기준틀 제시. 셋째, 색채계획의 단순화. 넷째, 도시문화를 형성. 다섯째, 색채계획에 관련된 학문에 응용 가능. 여섯째, 국가 문화산업, 콘덴츠 등 발전에 기여할 것으로 생각된다.