• Title/Summary/Keyword: network flow model

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Simulation and Analysis of a Gas Pipeline Network in Kyungin Area using Statistical Approach (경인지역 가스 수송을 위한 배관망시스템의 모사 및 분석)

  • Lee Eun-Lyong;Chang Seung-Yong;Kim In-Won
    • Journal of the Korean Institute of Gas
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    • v.1 no.1
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    • pp.14-20
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    • 1997
  • Pipeline network analysis requires fluid mechanics. A lot of equations have been used for flow analysis according to the behavior of fluid in pipelines and the operative situations. In this paper, simulation and analysis have been performed for the pipeline network system in Kyungin area using a steady-state mathematical model. Then, a statistical model using partial least squares(PLS) method has been developed with the data obtained from the developed mathematical model. The results showed that it is possible to simulate and analyze pipeline network systems using statistical approach.

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Application of Linear and Nonlinear Analysis Technique on the Complex Water Distributing System (복합배수관망에 있어서 선형 및 비선형 해석기법의 적용)

  • 고수현;최윤영;안승섭
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.4
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    • pp.69-78
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    • 2001
  • In this study optimal analysis of pipe network was performed using linear and non linear analysis method for complex real pipe network system of Mungyeong water purification field system which consists of 70 nodes and 86 elements. From the examination result of total flow which is distributed to each pipe, it is found that KYPIPE2 Model supplies less amount than NLAM. It is known that dynamic water level and pressure head of KYPIPE2 Model and NLAM are nearly in accordance with each other from each method of the pipe network analyses, and appeared that both methods of analysis shows high reliable result since the distribution of dynamic water level for every node is the short range of EL. 205.0m~EL. 210.0m besides the pressed dynamic water level. The analysis results of pressure in the methods of pipe network analysis for KYPIPE2 Model and NLAM are similar and it is satisfactory result that the pressure distributions of the tab water design criterion of 5.0kgf/cm$^2$ besides the small part of highland.

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Numerical Simulation and Experimental Studies on Lubricating System of Scroll Compressor (스크롤 압축기 윤활시스템의 수치해석과 실험)

  • 이진갑;김종봉
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.2
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    • pp.108-115
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    • 2004
  • Experiment and analytical studies on the oil supply characteristics of scroll compressor have been presented. For a scroll compressor, oil supply system consisting of individual lubricating element such as pumps, oil passages and sliding surfaces has been modeled by equivalent electric circuit. By solving the closed network equations of the model, oil flow rates at various lubrication elements could be obtained. Total amount of the oil flow rate drawn into the shaft has been measured and compared reasonably well with the prediction by the numerical simulation.

Load Flow Algorithm Analysis of Distribution System (배전계통 부하조류계산 알고리즘 비교 분석)

  • Kwak, Do-Il;Kim, Tae-Eung;Ryu, Jae-Hong;Kim, Jae-Eon
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.134-136
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    • 1999
  • Not much work has been carried out on the load flow analysis of distribution networks. This paper introduces Newton-Raphson method using Distflow equation and Forward Sweeping method in the distribution networks. And that efficient solution scheme in a radial distribution network is presented. Also, simulation results of both Newton-Raphson method and Forward Sweeping method applied to a 22.9kV distribution system model with 120 load buses are analized and evaluated.

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Assay development and HTS on microfluidic Lab-on-a-chip

  • Yang, Eun-Gyeong
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2002.07a
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    • pp.73-78
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    • 2002
  • Microfluidic lab-on-a-chip (LOC) systems have enabled a new generation ofassay technologies in chemical and biomedical sciences. Caliper's microfluidic LOC systems contain a network of microscopic channels through which fluids and chemical are moved in order to perform experiments. The main advantages of these continuous-flow devices are integration and automation of multiple steps in complex analytical procedures to improve the reproducibility of the results, and eliminated the manual labor, time and pipetting errors involved in analyses. The present talk is devoted to give a brief introduction of microfluidic basics and to present in applying continuous-flow microchips to drug screening with model enzyme assays.

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Maximal-Flow-Problem with transit priority in a track (통과 우선순위가 있는 선로의 최대 흐름문제)

  • 이달상;김만식
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.13 no.21
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    • pp.111-117
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    • 1990
  • This paper treats the problem to schedule for train with low transit priority so as to maximizing the number that can be sent during given time without interfering with the fixed schedule for train with high transit priority in a track. We transform the this problem into Time-Expanded Network without traverse time through application of Ford-Fulkerson Model, develop a TENET GENerator(TENETGEN) and obtain the data of TENET using developed TENETGEN. Finally, we seek the optimal solution to these data with Dinic's Maximal-Flow Algorithm and examine the availability of our procedures in personal computer.

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A Numerical study on characteristics of fluid flow in a three-dimensional discrete fracture network with variation of length distributions of fracture elements (3차원 이산 균열망 흐름장에서 균열요소의 길이분포 변화에 따른 내 유체 흐름 특성에 관한 수치적 연구)

  • Jeong, Woochang
    • Journal of Korea Water Resources Association
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    • v.52 no.2
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    • pp.149-161
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    • 2019
  • In this study, the effect of the fluid flow characteristics on the length distribution of the fracture elements composing the fracture network is analyzed numerically using the 3D fracture crack network model. The truncated power-law distribution is applied to generate the length distribution of the fracture elements and the simulations of fluid flow are carried out with the exponent ${\beta}_l$ from 1.0 to 6.0. As a result of simulations, when the exponent ${\beta}_l$ increases, the length distribution of the fracture elements gradually decreases, and the connectivity between the fracture elements affecting the permeability of the fracture network becomes weak. When we analyzed the distributions of flow rate calculated at each fracture element with the exponent ${\beta}_l$, the mean flow rate at ${\beta}_l=1.0$ was estimated to be about 447 times larger than that at ${\beta}_l=6.0$ and for the flow calculated at the outflow boundary of the fracture network, the case of ${\beta}_l=1.0$ was estimated to be 6,440 times larger than that of ${\beta}_l=6.0$.

Performance Improvement of LSU Algorithms in QoS Routing (QoS 라우팅의 LSU 알고리즘 성능 향상 기법)

  • Cho, Kang-Hong
    • The Journal of the Korea Contents Association
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    • v.9 no.3
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    • pp.49-57
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    • 2009
  • This paper has proposed Flow Holding Time based Link State Update(LSU) Algorithm that can improve the performance of the existing LSU algorithms. As the existing LSU algorithms are based on the network traffic information, the proposed algorithm is based on flow holding time so we can minimize the LSU message overhead and has not had a strong influence on the depreciation of QoS routing performance. We apply a flow holding time in order to decrease the number of LSU message. We have evaluated the performance of the proposed model and the existing algorithms on MCI simulation network using the performance metric as the QoS routing blocking rate and the mean update rate per link, it thus appears that we have verified the performance of this algorithm.

Control of temperature distribution in a thermal stratified tunnel by using neural networks (신경회로망을 이용한 열성층 풍동내의 온도 분포 제어)

  • 부광석;김경천
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.147-150
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    • 1996
  • This paper describes controller design and implementation method for controlling the temperature distribution in a thermal stratified wind tunnel(TSWT) by using a neural network algorithm. It is impossible to derive a mathematical model of the relation between heat inputs and temperature outputs in the test section of the TSWT governed by a nonlinear turbulent flow. Thus inverse neural network models with a multi layer perceptron structure are used in a feedforward control loop and feedback control loop to generate an arbitrary temperature distribution in the test section of the TSWT.

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Numerical Simulation of Groundwater Flow in Feterogenetic Rockmass of Unsaturated Condition (암반의 불균질성을 고려한 불포화대 지하수 유동 평가)

  • Ha, Jaechul;Lee, Jeong Hwan;Cheong, Jae-yeol;Jung, Haeryong
    • The Journal of Engineering Geology
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    • v.26 no.1
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    • pp.87-99
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    • 2016
  • We present the results of two-dimensional numerical simulations predicting the flow of groundwater in a fractured unsaturated zone. We applied the k-field distribution of permeability derived from discrete fracture network (DFN) modeling as the hydraulic properties of a model domain. To model an unsaturated zone, we set the depth from the ground surface to the underground aquifer. The rate of water infiltration into the unsaturated zone was divided into two parts, an artificial structure surface and unsaturated soil zone. The movement of groundwater through the unsaturated zone was simulated with particular emphasis on contaminant transport. It was clearly observed that the contaminants dissolved in groundwater transported vertically from the ground surface to the saturated zone.