• 제어로봇시스템학회논문지
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• 제21권3호
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• pp.187-193
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• 2015

When developing a vehicle control system, simulation methods are widely used to validate the whole system in the early development phase. With this regard, the simulator should correctly behave just like the real parts that are not yet implemented while interacting with already implemented parts in real-time. However, most simulators cannot provide functionally and temporally accurate behaviors of the target system. In order to overcome this limitation, this paper proposes a novel real-time simulation technique that can efficiently simulate the temporal behavior as well as the functional behavior of the simulation target system.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1994년도 추계학술발표회 및 정기총회
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• pp.1-2
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• 1994

With the prevalence of computers in modern organizations, simulation is receiving more atention as an effectvie decision -making tool. Simualtion is a computer-based numerical technique which uses mathmatical and logical models to approximate the behaviror of a real-world system. However, iptimization of synamic stochastic systems often defy analytical and algorithmic soluions. Although a simulation approach is often free fo the liminting assumption s of mathematical modeling, cost and time consiceration s make simulation the henayst's last resort. Therefore, whenever possible, analytical and algorithmica solutions are favored over simulation. This paper discussed the issues and procedrues for using simulation as a tool for optimization of stochastic complex systems that are dmodeled by computer simulation . Its emphasis is mostly on issues that are speicific to simulation optimization instead of consentrating on the general optimizationand mathematical programming techniques . A simulation optimization problem is an optimization problem where the objective function. constraints, or both are response that can only be evauated by computer simulation. As such, these functions are only implicit functions of decision parameters of the system, and often stochastic in nature as well. Most of optimization techniqes can be classified as single or multiple-resoneses techniques . The optimization of single response functins has been researched extensively and consists of many techniques. In the single response category, these strategies are gradient based search techniques, stochastic approximate techniques, response surface techniques, and heuristic search techniques. In the multiple response categroy, there are basically five distinct strategies for treating the responses and finding the optimum solution. These strategies are graphica techniqes, direct search techniques, constrained optimization techniques, unconstrained optimization techniques, and goal programming techniques. The choice of theprocedreu to employ in simulation optimization depends on the analyst and the problem to be solved. For many practival and industrial optimization problems where some or all of the system components are stochastic, the objective functions cannot be represented analytically. Therefore, modeling by computersimulation is one of the most effective means of studying such complex systems. In this paper, after discussion of simulation optmization techniques, the applications of above techniques will be presented in the modeling process of many flexible manufacturing systems.

• The Journal of the Acoustical Society of Korea
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• 제21권1E호
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• pp.42-48
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• 2002

In this paper, a computer simulation method is presented far the dynamic analysis of a hydraulic engine mount system. The hydraulic engine mount system controls the damping characteristics using the viscosity of fluid flow. The complex stiffnesses of the main rubber for the hydraulic engine mount system are computed using a finite element analysis. The equations of motion considering the parameters of the hydraulic engine mount system are derived. To investigate the effects of the hydraulic engine mount system, the computer simulation running over a typical rough road is carried out using a vehicle dynamic model. These results are compared with those of the conventional rubber mount system.

• 한국재료학회지
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• 제11권11호
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• pp.929-935
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• 2001

Two-dimensional computer simulations were conducted on percolation structure in which second phases of various aspect ratios were arranged in a lattice (matrix). The second phases were randomly arranged in an array with two different computational programs; one prohibiting an overlap among second phases and the other allowing the overlap. From the simulation prohibiting the overlap, it was predicted that a complete path was formed at less amounts of the second phase with higher aspect ratios. In the simulation allowing the overlap, a complete path throughout the array was formed by arranging the second phase of an aspect ratio of 1. 5, 20, 100 with less than 59%, 43%, 19%, 4% in the array, respectively.

• 인터넷정보학회논문지
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• 제19권6호
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• pp.53-62
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• 2018

최근 컴퓨터 하드웨어의 성능이 증가함에 따라, 휴대용 전자 기기 뿐만 아니라 개인 컴퓨터에서도 더 사실적인 컴퓨터 그래픽 물체들을 생성하고 보여줄 수 있게 되었다. 이러한 이유로, 컴퓨터 그래픽을 포함한 디지털 콘텐츠는 더 계산적 비용이 높은 사실적인 가상의 물체들을 다양한 기기에서 실시간으로 표현하는 것을 요구한다. 멀티-플랫폼에서 구동되며 컴퓨터 그래픽을 포함한 게임, 애니메이션 등의 콘텐츠의 제작을 돕기 위해서는 유니티와 언리얼 엔진과 같은 기술들이 주로 사용된다. 시뮬레이션에서 더 사실적인 가상의 물체의 움직임을 표현하기 위해서는, 가상의 물체는 다른 물체들과 충돌해야 하며 현실세계와 비슷한 반응을 보여야 한다. 하지만, 다이나믹 시뮬레이션은 많은 계산 비용을 요구하나, 대부분의 휴대용 기기들을 이러한 다이나믹 시뮬레이션을 실시간으로 제공하지 못한다. 본 논문에서는 GPGPU 계산을 이용하여 구형 물체와 실시간으로 충돌 및 반응을 수행하는 천 시뮬레이션을 제안한다. 제안된 방법이 사실적인 디지털 콘텐츠에 유용할 것으로 기대된다.

• Journal of International Society for Simulation Surgery
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• 제2권2호
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• pp.80-82
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• 2015

The mandibuloplasty for the facial aesthetic reason has been the one of the most popular procedures in aesthetic facial bone surgery in East Asia. Most East Asian women prefer smaller-looking and smooth-shaped facial contour. Prominent mandible angle which are common in Asia would be the main problem for smooth facial contour. In addition, recently, the mandibular body and broad chin shape also are known to be remodeled in order to get the ideal smooth facial shape. However, mandibuloplasty is not that easy to cut because many patients has inward mandibular angle and the visual field in operation is limited. The aim of this trial is to try to provide the prefabricated cutting guide for the symmetric and appropriate mandibuloplasty with the surgeons. Preoperative computed tomography(CT) data were processed for the patient and computer simulation model was produced. Then, mandibuloplasty was done on the computer simulation screen. Based on this data, customized cutting guide was made. This prefabricated cutting guide was used in real mandibuloplasty bilaterally. Premade cutting guide for the mandibuloplasty based on the computer simulation turned out to be very successful in this patient. Individualized approach for each patient could be an ideal way to manage the patients in near future.

• 산업공학
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• 제2권2호
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• pp.51-62
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• 1989

A computer-aided simulation modeling system has been developed to allow the automatic construction of complete discrete simulation models for queueing systems. Three types of knowledge are used in the specification and construction of a simulation modeling: Knowledge of queueing system, simulation modeling, and a target simulation language. This knowledge has been incorporated into the underlying rule base in the form of extraction and construction rule, and implemented via the expert system building tool, OPS5. This paper suggested a knowledge based approach for automatic programming to enable a user who lacks modeling knowledge and simulation language expertize to quickly build executable models.

• Journal of Biosystems Engineering
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• 제15권4호
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• pp.290-297
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• 1990

The purposes of this study were to perform theoretical analysis of an electronic-hydraulic hitch control system for position and draft control of tractor implements and to investigate the performance of the control system through computer simulation. Computer simulation models which could predict the responses of the system to the step and sinusoidal inputs in position and draft controls were developed using the simulation package "TUTSIM". The effects of control mode, hydraulic flow rate, deadband, and proportional constant on control performance of the system were investigated. The simulated results were compard with the experimental ones to verify the simulation models. The simulation models appeared to be a useful means for the analysis and the design of the electronic-hydraulic hitch control system.

• Journal of information and communication convergence engineering
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• 제1권4호
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• pp.169-173
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• 2003

The performance of modern mainframe computers keeps increasing due to the advances in the semiconductor technology. However, the quest for the faster computer has never been satisfied. To overcome the discrepancy in the supply and demand, we studied a high performance computer architecture utilizing a three-dimensional Holographic Data Storage Systems (HDSS) as a secondary storage system. The HDSS can achieve a high storage density by utilizing the third dimension. Furthermore, the HDSS can exploit the parallelism by processing the two-dimensional data in a single step. To compare the performance of the HDSS with the conventional hard disk based storage system, we modeled the HDSS using the DiskSim simulation engine and performed the simulation study. Results showed that the HDSS can improve the access time by 1.7 times.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.505-506
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• 2006

This study is focused on the manufacturing technique of powder injection molding of watch case made from zirconia powder. A series of computer simulation processes were applied to the prediction of the flow pattern in the inside of the mould and defects as weld-line. The material properties of melted feedstock, including the PVT graph and thermal viscosity flowage properties were measured to obtain the input data to be used in a computer simulation. Also, a molding experiment was conducted and the results of the experiment showed a good agreement with the simulation results for flow pattern and weld line location. On the other hand, gravity and inertia effects have an influence on the velocity of the melt front because of the high density of ceramic powder particles during powder injection molding in comparison with polymer's injection molding process. In the experiment, the position of the melt front was compared with the upper gate and lower gate positions. The gravity and inertia effect could be confirmed in the experimental results.