• Title/Summary/Keyword: Simulation algorithm

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Reverse-Simulation Method for Single Run Simulation Optimization (단일 실행 시뮬레이션 최적화를 위한 Reverse-Simulation 기법)

  • 이영해
    • Journal of the Korea Society for Simulation
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    • v.5 no.2
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    • pp.85-93
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    • 1996
  • Simulation is commonly used to find the best values of decision variables for problems which defy analytical solutions. This objective is similar to that of optimization problems and thus, mathematical programming techniques may be applied to simulation. However, the application of mathematical programming techniques, e.g., the gradient methods, to simulation is compounded by the random nature of simulation responses and by the complexity of the statistical issues involved. In this paper, therefore, we explain the Reverse-Simulation method to optimize a simulation model in a single simulation run. First, we point the problem of the previous Reverse-Simulation method. Secondly, we propose the new algorithm to solve the previous method and show the efficiency of the proposed algorithm.

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A Study on the UPFC Dynamic Simulation Algorithm for Low Frequency Oscillation Studies (저주파 진동 해석을 위한 UPFC의 동적 시뮬레이션 알고리즘에 관한 연구)

  • Son, Kwang-Myoung
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.10
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    • pp.502-508
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    • 2000
  • This paper presents a dynamic simulation algorithm for studying the effect of United Power Flow Controller(UPFC) on the low frequency power system oscillations and transient stability studies. The proposed algorithm is a Newton-type one and uses current injection type UPFC model, which gives a fast convergence characteristics. The algorithm is applied to studying inter-area power oscillation damping enhancement of a sample two-area power system both in time domain and frequency domain. The case study results show that the proposed algorithm is very efficient and UPFC is very effective and robust against operating point change.

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A Fuzzy Dispatching Algorithm with Adaptive Control Rule for Automated Guided Vehicle System in Job Shop Environment (AGV시스템에서 적응 규칙을 갖는 퍼지 급송알고리듬에 관한 연구)

  • 김대범
    • Journal of the Korea Society for Simulation
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    • v.9 no.1
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    • pp.21-38
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    • 2000
  • A fuzzy dispatching algorithm with adaptable control scheme is proposed for more flexible and adaptable operation of AGV system. The basic idea of the algorithm is prioritization of all move requests based on the fuzzy urgency. The fuzzy urgency is measured by the fuzzy multi-criteria decision-making method, utilizing the relevant information such as incoming and outgoing buffer status, elapsed time of move request, and AGV traveling distance. At every dispatching decision point, the algorithm prioritizes all move requests based on the fuzzy urgency. The performance of the proposed algorithm is compared with several dispatching algorithms in terms of system throughput in a hypothetical job shop environment. Simulation experiments are carried out varying the level of criticality ratio of AGVs , the numbers of AGVs, and the buffer capacities. The rule presented in this study appears to be more effective for dispatching AGVs than the other rules.

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Efficient Algorithm for the Solidification Simulation by FDM (FDM에 의한 응고해석시 계산기간 단축을 위한 Algorithm연구)

  • Lee, Jae-Kyung;Jeon, Ju-Mae;Jun, Ghi-Chan
    • Journal of Korea Foundry Society
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    • v.14 no.5
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    • pp.412-418
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    • 1994
  • Efficient algorithm for the solidification simulation by FDM is described from the practical point of views. If a proper time step ${\Delta}t$ is selected, the calculation is accelerated by implicit algorithm with the temperature recovery method of latent heat method. The implicit routine in the calculation is processed by SOR method(relaxation factor=1.5, truncation error=$10^{-4}$). The calculation is more accelerated by linear-interpolated explicite algorithm with a time step larger than the minimum value of the time step. This explicit method, which is applicable to the practical casting simulation problems, produces almost same results with about 40% faster calculation speed compared with the conventional explicit method.

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Computer simulation for seam tracking algorithm using laser vision sensor in robotic welding (레이저 비전 센서를 이용한 용접선 추적에 관한 시뮬레이션)

  • Jung, Taik-Min;Sung, Ki-Eun;Rhee, Se-Hun
    • Laser Solutions
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    • v.13 no.2
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    • pp.17-23
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    • 2010
  • It is very important to track a complicate weld seam for the welding automation. Very recently, laser vision sensor becomes a useful sensing tool to find the seams. Until now, however studies of welding automation using a laser vision sensor, focused on either image processing or feature recognition from CCD camera. Even though it is possible to use a simple algorithm for tracking a simple seam, it is extremely difficult to develop a seam-tracking algorithm when the seam is more complex. To overcome these difficulties, this study introduces a simulation system to develop the seam tracking algorithm. This method was verified experimentally to reduce the time and effort to develop the seam tracking algorithm, and to implement the sensing device.

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A Lane-change Collision Avoidance Algorithm for Autonomous Vehicles and HILS(Hardware-In-the-Loop Simulation) Test (자율주행 차량의 충돌회피 차선변경 제어 알고리즘 개발과 HILS 시험)

  • 류제하;김종협
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.5
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    • pp.240-248
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    • 1999
  • This paper presents a lane-change collision avoidance control algorithm for autonomous vehicles that will be used in AHS(Automated Highway System). In the proposed control algorithm, nominal control inputs are generated by solving the inverse vehicle dynamic equations of motion for a lane-change maneuver. In addition, a corrective steering input from preview as well as DYC (Direct Yaw Moment Control) may be included to reduce unpredictable errors and to insure yaw directional stability, respectively. The performance of the algorithm is evaluated with an ABS HILS system which consist of 17 DOF vehicle model and real ABS hardware parts. The HILS simulation results show that the proposed algorithm may be used for emergency lane-change maneuvers for autonomous vehicles.

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Evaluation of A Direct Yaw Moment Control Algorithm by Brake Hardware-In-The -Loop Simulation (브레이크HILS를 이용한 능동 요모멘트 제어 알고리즘의 평가)

  • 류제하;김호수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.8
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    • pp.172-179
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    • 1999
  • This paper presents a simple but effective DYC algorithm which enhances vehicle lateral stability by using an anti=lock brake system (ABS). In the proposed algorithm, only the front outer wheel is controlled during cornering maneuver instead of controlling all four wheels because the wheel has the largest role in DYC and it is easy and simple to control the only one wheel. An ABS Hardware - In -The -Loop Simulation ( HILS) system that may be used to realistically test real vehicle dynamic behavior in a lab is used for evaluating the proposed DYC algorithm in severe situations where a vehicle is destabilized without DYC . The HILS results show that the proposed DYC algorithm has the potential of maintaining vehicle stability in some dangerous situations.

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Optimization of PI Controller Gain for Simplified Vector Control on PMSM Using Genetic Algorithm

  • Jeong, Seok-Kwon;Wibowo, Wahyu Kunto
    • Journal of Power System Engineering
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    • v.17 no.5
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    • pp.86-93
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    • 2013
  • This paper proposes the used of genetic algorithm for optimizing PI controller and describes the dynamic modeling simulation for the permanent magnet synchronous motor driven by simplified vector control with the aid of MATLAB-Simulink environment. Furthermore, three kinds of error criterion minimization, integral absolute error, integral square error, and integral time absolute error, are used as objective function in the genetic algorithm. The modeling procedures and simulation results are described and presented in this paper. Computer simulation results indicate that the genetic algorithm was able to optimize the PI controller and gives good control performance of the system. Moreover, simplified vector control on permanent magnet synchronous motor does not need to regulate the direct axis component current. This makes simplified vector control of the permanent magnet synchronous motor very useful for some special applications that need simple control structure and low cost performance.

Application of Ray Following Algorithm to High Resolution Satellite Image Simulation

  • Shin, Dong-Seok;Park, Won-Kyu
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.559-564
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    • 2002
  • This paper describes a new algorithm named as ray following algorithm which is applied for high-resolution satellite image simulation. The problems of the conventional ray tracing algorithm are pointed out especially when terrain elevations vary abruptly. The proposed algorithm follows the directional ray vector sequentially and thoroughly in order to determine the crossing point of the ray with the terrain surface. This way of sequential height comparison method is regarded as the only way to obtain accurate surface cross-section when a highly variant digital surface model is used. The experimental results show and compare the validities of the conventional and proposed algorithms.

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Development and Performance Evaluation of a Car Assignment and Routing Algorithm for Reducing Transportation Cost in a Logistics System (물류시스템에서 운송비를 줄이기 위한 차량 할당 및 경로 설정 알고리즘 개발 및 성능평가)

  • 조병헌
    • Journal of the Korea Society for Simulation
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    • v.8 no.3
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    • pp.91-103
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    • 1999
  • This paper proposes an algorithm which reduces transportation cost while goods are delivered in time in a logistics system. The logistics system assumed in this paper is the system in which multiple cars moves various goods from spatially distributed warehouses to stores. For reducing transportation cost, the car assignment algorithm which allocates goods to minimal cars employs the BF method; routing of each car is modelled as the TSP and is solved by using the genetic algorithm. For evaluating the proposed algorithm, the logistics system is modelled and simulated by using the DEVS formalism. The DEVS formalism specifies discrete event systems in a hierarchical, modular manner. During simulation, each car is modelled as a message and traverses warehouse and stores. When a car arrives at a warehouse or a store, predetermined amount of goods are loaded or unloaded. The arrival time and departure time of cars are analyzed and eventually whether goods are delivered in the desired time bound is verified.

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