• Title/Summary/Keyword: Computer simulation and developed model

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Development and Evaluation of SWAT Topographic Feature Extraction Error(STOPFEE) Fix Module from Low Resolution DEM (저해상도 DEM 사용으로 인한 SWAT 지형 인자 추출 오류 개선 모듈 개발 및 평가)

  • Kim, Jong-gun;Park, Youn-shik;Kim, Nam-won;Chung, Il-moon;Jang, Won-seok;Park, Jun-ho;Moon, Jong-pil;Lim, Kyoung Jae
    • Journal of Korean Society on Water Environment
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    • v.24 no.4
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    • pp.488-498
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    • 2008
  • Soil and Water Assessment Tool (SWAT) model have been widely used in simulating hydrology and water quality analysis at watershed scale. The SWAT model extracts topographic feature using the Digital Elevation Model (DEM) for hydrology and pollutant generation and transportation within watershed. Use of various DEM cell size in the SWAT leads to different results in extracting topographic feature for each subwatershed. So, it is recommended that model users use very detailed spatial resolution DEM for accurate hydrology analysis and water quality simulation. However, use of high resolution DEM is sometimes difficult to obtain and not efficient because of computer processing capacity and model execution time. Thus, the SWAT Topographic Feature Extraction Error (STOPFEE) Fix module, which can extract topographic feature of high resolution DEM from low resolution and updates SWAT topographic feature automatically, was developed and evaluated in this study. The analysis of average slope vs. DEM cell size revealed that average slope of watershed increases with decrease in DEM cell size, finer resolution of DEM. This falsification of topographic feature with low resolution DEM affects soil erosion and sediment behaviors in the watershed. The annual average sediment for Soyanggang-dam watershed with DEM cell size of 20 m was compared with DEM cell size of 100 m. There was 83.8% difference in simulated sediment without STOPFEE module and 4.4% difference with STOPFEE module applied although the same model input data were used in SWAT run. For Imha-dam watershed, there was 43.4% differences without STOPFEE module and 0.3% difference with STOPFEE module. Thus, the STOPFEE topographic database for Soyanggang-dam watershed was applied for Chungju-dam watershed because its topographic features are similar to Soyanggang-dam watershed. Without the STOPFEE module, there was 98.7% difference in simulated sediment for Chungju-dam watershed for DEM cell size of both 20 m and 100 m. However there was 20.7% difference in simulated sediment with STOPFEE topographic database for Soyanggang-dam watershed. The application results of STOPFEE for three watersheds showed that the STOPFEE module developed in this study is an effective tool to extract topographic feature of high resolution DEM from low resolution DEM. With the STOPFEE module, low-capacity computer can be also used for accurate hydrology and sediment modeling for bigger size watershed with the SWAT. It is deemed that the STOPFEE module database needs to be extended for various watersheds in Korea for wide application and accurate SWAT runs with lower resolution DEM.

Three Dimensional Solidification Analysis in Large Steel Castings by Modified Finite Difference Method (개량차분법에 의한 대형주강품의 3차원 응고해석)

  • Yoo, Seung-Mog;Lee, Doo-Ho;Kim, Jong-Ki;So, Chan-Young;Hong, Chun-Pyo
    • Journal of Korea Foundry Society
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    • v.11 no.1
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    • pp.54-62
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    • 1991
  • A computer program which consists of pre-processor, main solidification simulator and post-processor has been developed for three dimensional solidification analysis of steel castings. The pre-processor is used for mesh generation in a small personal computing system. The modified finite difference method is adopted for the main solidification simulation algorithm. The post -processor graphically presents the simulation results and shows the formation of shrinkage defects. Several experiments on large steel castings in sand mold were carried out. The temperature variations in casting and mold with time are measured experimentally, and the results are compared with calculation results. Several numerical examples for the prediction of shrinkage cavity in large steel casting of SC42 and SCNCrM2 alloys are compared with experimental results. The effect of sleeve and chills on solidification patterns are also studied. Formation of shrinkage defects for the three cases of experimental castings are relatively well predicted by present model.

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A Simulator for the Design and Operation of the Steel Mill (제강.연주 공장 설계와 운영을 위한 시뮬레이터)

  • Choi, Seong-Hoon
    • Journal of the Korea Society for Simulation
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    • v.20 no.2
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    • pp.49-57
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    • 2011
  • Stiff competition and skyrocketing prices of raw materials are increasingly demanding the optimal design and operation of iron and steel mills minimizing trial and error. Computer simulation can provide the methodology in accordance with requirements. The purpose of this paper is to suggest a simulator for the design and operation of the steelmaking and continuous casting mill. The simulator was developed using Arena, popular simulation software and input and output interface based on MS Excel. It allows easy access for the maintenance and extension of the model. One of distinct features of the proposed simulator is the inclusion of complex transportation modules composed of transfer cars and overhead cranes. The simulator can be used for evaluating various alternative designs of a projected mill via throughput analysis and material flow analysis. Also, one can utilize it effectively to search for the best product mix suitable for many types of situations. It could be an invaluable tool evaluating the performance of operation patterns and improving the accuracy.

An approach to hybrid system modeling and control for the mobile robot systems (차륜형 이동로봇 시스템의 하이브리드 시스템 모델과 제어)

  • 임진모;임미섭;임준홍
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.231-236
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    • 1997
  • We propose the hybrid control for the path control of wheeled mobile robot system. To develop the hybrid control of mobile robot, the continuous dynamics of mobile robot are modeled by the switched systems. The abstract model and digital automata for the path control are developed. This hybrid control system has the 3-layered hierachical structure : digital automata as the higher process, mobile robot system as the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. The control of following the desired-paths with edges are investigated as the applications by the computer simulation.

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Dynamic Control of Robot Manipulators Using Multilayer Neural Networks and Error Backpropagation (다층 신경회로 및 역전달 학습방법에 의한 로보트 팔의 다이나믹 제어)

  • 오세영;류연식
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.39 no.12
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    • pp.1306-1316
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    • 1990
  • A controller using a multilayer neural network is proposed to the dynamic control of a PUMA 560 robot arm. This controller is developed based on an error back-propagation (BP) neural network. Since the neural network can model an arbitrary nonlinear mapping, it is used as a commanded feedforward torque generator. A Proportional Derivative (PD) feedback controller is used in parallel with the feedforward neural network to train the system. The neural network was trained by the current state of the manipulator as well as the PD feedback error torque. No a priori knowledge on system dynamics is needed and this information is rather implicitly stored in the interconnection weights of the neural network. In another experiment, the neural network was trained with the current, past and future positions only without any use of velocity sensors. Form this thim window of position values, BP network implicitly filters out the velocity and acceleration components for each joint. Computer simulation demonstrates such powerful characteristics of the neurocontroller as adaptation to changing environments, robustness to sensor noise, and continuous performance improvement with self-learning.

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A Study on the Development of the Large Building Air-conditioning System with the Regenerative Ice-energy and its Computer Aided Design (빙축열을 이용한 대형빌딩 공기조화시스템 개발과 설계전산화에 관한 연구)

  • 권형정;김원영;김용모;김경근
    • Journal of Advanced Marine Engineering and Technology
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    • v.15 no.5
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    • pp.38-46
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    • 1991
  • In the design of an electric power plant, the capacity to meet the peak load demand is one of the important factors to be considered. This peak load usually occurs when the most of the cooling air-conditioning systems are being operated during daytime in summer season. Therefore, it is necessary to construct an additional electric power plant and to develop the new air-conditioning system for relieving the peak load. This paper analysed the performance characteristics of this experimental regenerative ice energy system by means of a bundle of the heat-pipes. And the result of this analysis was applied to the simulation of an air-conditioning system model. Also, an operation program of moisture air was made according to air load and in order to computerize the air-conditioning system a CAD program was developed by the properties of moisture air.

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3D finite element analysis of the whole-building behavior of tall building in fire

  • Fu, Feng
    • Advances in Computational Design
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    • v.1 no.4
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    • pp.329-344
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    • 2016
  • In this paper, a methodology to simulate the whole-building behaviour of the tall building under fire is developed by the author using a 3-D nonlinear finite element method. The mechanical and thermal material nonlinearities of the structural members, such as the structural steel members, concrete slabs and reinforcing bars were included in the model. In order to closely simulate the real condition under the conventional fire incident, in the simulation, the fire temperature was applied on level 9, 10 and 11. Then, a numerical investigation on the whole-building response of the building in fire was made. The temperature distribution of the floor slabs, steel beams and columns were predicted. In addition, the behaviours of the structural members under fire such as beam force, column force and deflections were also investigated.

Visual servo control of robots using fuzzy-neural-network (퍼지신경망을 이용한 로보트의 비쥬얼서보제어)

  • 서은택;정진현
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.566-571
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    • 1994
  • This paper presents in image-based visual servo control scheme for tracking a workpiece with a hand-eye coordinated robotic system using the fuzzy-neural-network. The goal is to control the relative position and orientation between the end-effector and a moving workpiece using a single camera mounted on the end-effector of robot manipulator. We developed a fuzzy-neural-network that consists of a network-model fuzzy system and supervised learning rules. Fuzzy-neural-network is applied to approximate the nonlinear mapping which transforms the features and theire change into the desired camera motion. In addition a control strategy for real-time relative motion control based on this approximation is presented. Computer simulation results are illustrated to show the effectiveness of the fuzzy-neural-network method for visual servoing of robot manipulator.

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The Forging Analysis of S/CAM Shaft to the Drum Brake (드럼브레이크 S/CAM 샤프트 단조 해석)

  • Kim, Mi-Ae;Sung, Back-Sub;Cha, Yong-Hoon
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1113-1118
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    • 2008
  • In the hot forging process, The forging defects that are caused by metal were strain, temperate, and inclusion. In this paper, the computer simulation analyzed the effective plastic strain and temperature behaviors. The quantitative analyses which proposed the effective mold design of S/CAM shaft was executed. The parameters of forging shape that affected on the optimize conditions that was calculated with simple equation were investigated. it is expected that the developed analysis model and design technique would greatly contribute to the drum brake optimal design considering temperature affected and material behaviors. This development could save more than 20% of production cost and reduced failure rate to more than 30%. By improving the life span of mold from 15,000 to 25,000, financial difficulty of company imposed on a mold manufacture could be overcome.

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Establishment of calculation methodology and thermal analysis for the development of a water calorimeter

  • Kang, M.Y.;Kim, Junhyuck;Choi, H.D.
    • Nuclear Engineering and Technology
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    • v.52 no.11
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    • pp.2620-2629
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    • 2020
  • As an early stage in the development of a water calorimeter, this study established a computer simulation methodology for analyzing the thermal behavior of a water calorimeter based on radiation transport and energy deposition. As a result, this study developed a method wherein the energy deposition distribution, which is obtained by applying Monte Carlo methods in water calorimeters, is directly used as a heat source for the thermal analysis model. Based on the proposed method, heat transfer in a water vessel and the effect of thermistor self-heating were analyzed. Through an analysis of the water velocities with and without a water vessel, it was found that a water vessel can serve as a convection barrier. Furthermore, it was confirmed that when considering thermistor self-heating, the water temperature change at the thermistor location is 0.219 mK higher compared to that when the thermistor was not considered. Therefore, thermistor self-heating must be considered to analyze the thermal behavior of a water calorimeter more accurately.