• Title/Summary/Keyword: modelling and simulation

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Cosmic Dawn III: Simulating the Reionization of the Local Group

  • Ahn, Kyungjin
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.47.1-47.1
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    • 2021
  • Cosmic Dawn III (CoDa III) is the last of the series of simulations of the reionization of the Local Group, the galaxy cluster including the Milky Way and the M31. The simulation is based on the constrained initial condition, N-body and hydrodynamic simulation of structure formation, modelling of galaxy formation, calculation of radiation transfer, and calibration against the observed high-redshift galaxy luminosity function. We present various physical properties we observed and important lessons that could stimulate future observations.

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Simulation of Subassembly Production at Shipyards

  • Hertel, Erik;Nienhuis, Ubald;Steinhauer, Dirk
    • International Journal of CAD/CAM
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    • v.6 no.1
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    • pp.19-27
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    • 2006
  • To survive in the current shipbuilding industry it is of vital importance for shipyards to achieve an optimal utilization of resources, make an achievable planning and ensure that this planning is kept. Possible problems should be eliminated before production starts and if unexpected disturbances occur in the actual production the right measures should be taken. Due to the dynamic nature of the production process, the continuous variation in products and the complexity of both, all this can hardly be achieved with conventional static planning and analysis systems. Simulation provides a solution here, since this enables the modelling and evaluation of the dynamic relations between product and production process. After a global introduction to production simulation in general and the application of simulation at the Flensburger shipyard, this paper presents a tool that has been developed to simulate the various complex assembly processes taking place at shipyards. Subsequently the simulation model for the subassembly production at Flensburger, in which this tool is applied, will be discussed.

Workload Distribution and Performance Analysis Simulation for a Distributed Server Cluster System (분산 서버 클러스터 시스템의 부하 분산 및 성능 분석 시뮬레이션)

  • 최은미;이원규
    • Journal of the Korea Society for Simulation
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    • v.12 no.4
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    • pp.103-111
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    • 2003
  • A distributed sewer cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

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Workload Distribution and Performance Analysis Simulation for a Distributed Server Cluster System (분산 서버 클러스터 시스템의 부하 분산 및 성능 분석 시뮬레이션)

  • 최은미;이원규
    • Proceedings of the Korea Society for Simulation Conference
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    • 2003.11a
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    • pp.27-34
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    • 2003
  • A distributed server cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

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A Study on the Intelligent Control Pattern of the Automatic Transmission in Tracked Vehicles (궤도차량용 자동변속기의 지능형변속패턴에 관한 연구)

  • 강서익
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.10a
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    • pp.216-221
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    • 1998
  • dynamic modelling method is applied to the driving simulation which has the calculable model of engine, transmission, vehicle. And driving pattern is used for database by actual tests and analyzed in neural network system. The simulation is compared to real test results and structures to the tracked vehicle powertrain.

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Topics in TFT device physics and modelling

  • Migliorato, P.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.929-935
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    • 2005
  • This paper contains a review of methods to analise static and dynamic properties of trap states in TFTs. The Gap Density of States is extracted from C-V and I-V characteristics. Switch on transients and small signal ac measurements are used in conjunction with simulation and an analytic model to extract traps dynamic parameters.

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A study on the designing of a hybrid step motor and its prototype (Hybrid step motor의 설계 및 시작품 제작에 관한 연구)

  • 김광배;백문홍
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.377-382
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    • 1986
  • This paper describes the modelling method of hybrid step motors including magnetic saturation effects of iron parts and the simulation for design of a prototype. Based on the above procedure, the prototype of a step motor is produced and its characteristics are discussed.

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Modelling and simulation of the grid-interactive inverter (계통연계형 인버터의 모델링 및 시뮬레이션)

  • An, Gyo-Sang;Im, Hui-Cheon
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.1345-1347
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    • 2002
  • This paper describes the computer simulation results of the photovoltaic(PV) power system for the grid-connection. The major contents of this paper consist of the modeling of the PV power system for grid-connection, the analysis of the steady-state characteristics of the system, and the analysis of the transient-state characteristics of the system, respectively.

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Economical run strategy for Korea High Speed Train Prototype (한국형 고속전철 경제운전 전략)

  • Lee Tae-Hyung;Park Choon-Soo
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.1381-1385
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    • 2004
  • This paper presents a modelling methodology using fuzzy logic and train performance simulation for determining an economical running pattern for a high speed train which minimizes energy consumption under an given trip margin. The economical running pattern is defined with an economical maximum speed in traction phase, a speed at the end of coasting. As a case study, the simulation is carried out for an economical run of korea high speed train prototype, and the results of fuzzy model described.

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Fatigue Life Prediction for Electric Railway Catenary wires (가선재의 피로수명 예측)

  • Kim, Yong-Ki;Chang, Se-Ky
    • Proceedings of the KSR Conference
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    • 2003.10c
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    • pp.558-567
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    • 2003
  • The catenary wires are damaged by periodic running of train as well as repeated stress. The wires are also degraded by atmosphere corrosion at fields. Corrosion of wires increased surface roughness and deteriorated mechanical properties by providing fatigue crack initiation sited resulting in a bad effect on service life of the wires. Fatigue test of catenary wires performed to estimate service lifetime. Also, simulation to analyze stress on catenary wires was conducted through modelling the finite elements for dynamic behaviors of wires. Fatigue life of catenary wires was estimated with fatigue and simulation tests.

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