• Title/Summary/Keyword: minimum flow

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SEQUENTIAL AND PARALLEL ALGORITHMS FOR MINIMUM FLOWS

  • Ciurea, Eleonor;Ciupala, Laura
    • Journal of applied mathematics & informatics
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    • v.15 no.1_2
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    • pp.53-75
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    • 2004
  • First, we present two classes of sequential algorithms for minimum flow problem: decreasing path algorithms and preflow algorithms. Then we describe another approach of the minimum flow problem, that consists of applying any maximum flow algorithm in a modified network. In section 5 we present several parallel preflow algorithms that solve the minimum flow problem. Finally, we present an application of the minimum flow problem.

INVERSE MINIMUM FLOW PROBLEM

  • Ciurea, Eleonor;Deaconu, Adrian
    • Journal of applied mathematics & informatics
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    • v.23 no.1_2
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    • pp.193-203
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    • 2007
  • In this paper we consider the inverse minimum flow (ImF) problem, where lower and upper bounds for the flow must be changed as little as possible so that a given feasible flow becomes a minimum flow. A linear time and space method to decide if the problem has solution is presented. Strongly and weakly polynomial algorithms for solving the ImF problem are proposed. Some particular cases are studied and a numerical example is given.

Hydrological Studies on the best fitting distribution and probable minimum flow for the extreme values of discharge (極値流量의 最適分布型과 極値確率 流量에 關한 水文學的 硏究 -錦江流域의 渴水量을 中心으로-)

  • Lee, Soon-Hyuk;Han, Chung-Suck
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.21 no.4
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    • pp.108-117
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    • 1979
  • In order to obtain the basic data for design of water structures which can be contributed to the planning of water use. Best fitted distribution function and the equations for the probable minimum flow were derived to the annual minimum flow of five subwatersheds along Geum River basin. The result were analyzed and summarized as follows. 1. Type III extremal distribution was considered as a best fit one among some other distributions such as exponential and two parameter lognormal distribution by $x^2$-goodness of fit test. 2. The minimum flow are analyzed by Type III extremal distribution which contains a shape parameter $\lambda$, a location parameter ${\beta}$ and a minimum drought $\gamma$. If a minimum drought $\gamma=0$, equations for the probable minimum flow, $D_T$, were derived as $D_T={\beta}e^{\lambda}1^{y'}$, with two parameters and as $D_T=\gamma+(\^{\beta}-\gamma)e^{{\lambda}y'}$ with three parameters in case of a minimum drought ${\gamma}>0$ respectively. 3. Probable minimum flow following the return periods for each stations were also obtained by above mentioned equations. Frequency curves for each station are drawn in the text. 4. Mathematical equation with three parameters is more suitable one than that of two parameters if much difference exist between the maximum and the minimum value among observed data.

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Probability Funetion of Best Fit to Distribution of Extremal Minimum Flow and Estimation of Probable Drought Flow (극소치유량에 대한 적정분포형의 설정과 확률갈수량의 산정)

  • 김지학;이순탁
    • Water for future
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    • v.8 no.1
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    • pp.80-88
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    • 1975
  • In this paper the authors established the best fit distribution function by applying the concept of probabiaity to the annual minimum flow of nine areas along the Nakdong river basin which is one of the largest Korean rivers and calculated the probable minimum flow suitable to those distribution function. Lastly, the authors tried to establish the best method to estimate the probable minimun flow by comparing some frequency analysis methods. The results obtained are as follows (1) It was considered that the extremal distribution type III was the most suitable one in the distributional types as a result of the comparision with Exponential distribution, Log-Normal distribution, Extremal distribution type-III and so on. (2) It was found that the formula of extremal distribution type-II for the estimation of probable minimum flow gave the best result in deciding the probable minimum flow of the Nakdong river basin. Therfore, it is recommended that the probable minimum flow should be estimated by using the extremal distribution type-III method. (3) It could be understood that in the probable minimum flow the average non-excessive probability appeared to be $Po{\fallingdotseq}1-\frac{1}{2T}$ and gave the same values of the probable variable without any difference in the various methods of plotting technique.

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Experimental Study on Minimum Heat Flux Point of Liquid Film Flow (액막류의 MHF 점에 관한 실험적 연구)

  • Kim, Yeung-Chan
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.208-213
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    • 2001
  • The minimum heat flux conditions are experimentally investigated for the subcooled liquid film flow on the horizontal plate. The experimental results show that the minimum heat flux point temperature becomes higher with the increase of the velocity and the subcooling of the liquid film flow. However, the effect of distance from the leading edge of the heat transfer plate on the minimum heat flux is almost negligible. Also, the experimental results show that the propagation velocity of wetting front increase with increasing the velocity and the subcooling of the liquid film flow.

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A Method for Determining the Most Vital Arcs in Minimum Cost Flow Problem (최소비용문제에서 치명호를 결정하는 방법)

  • 안재근;정호연;박순달
    • Journal of the military operations research society of Korea
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    • v.25 no.2
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    • pp.84-96
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    • 1999
  • The purpose of this paper is to find the most vital arc in the minimum cost flow problem. The most vital arc is the arc whose removal results in the greatest influence in the costs or the amount of demands in a given minimum cost flow network. This problem can be well applied to the conflict situations such as military logistics network or communications network. In this situation, network user wants to know which arcs are the most vital to him so that he can reinforce these arcs against attack, while interdictor wants to destroy these arcs which increase the distance of the shortest path most through the network. When one of arcs is removed from the network of the minimum cost flow problem, two kinds of situations can be occurred ; breaking feasibility and increasing cost. In case of breaking feasibility, the rank of arcs are determined using the amount of modified flow in a related network which is made of modifying the optimal alternative of the minimum cost flow problem. The rank of arcs with the increased costs are determined by using a method which finds the directed cycle with the minimum cost in a related network.

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A Study on the Mathematical Equivalence and $\varepsilon$-Relaxation of Auction Algorithm for PCB Design (PCB 설계를 위한 Auction 알고리즘의 수학적 등가와 $\varepsilon$-이완법에 관한 연구)

  • 우경환;이용희;임태영;이천희
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.213-216
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    • 2000
  • Minimum-cost linear network flow problems could be transformed with equal to assignment problems. Traditional method to solve the linear network flow problems are improved source-cost by transform the simple cycle flow. Auction algorithm could be applied to same element using the initial target price and dispersion calculation. Also, each elements are obtained by $\varepsilon$-relaxation methods. In this paper we proposed; 1)minimum-cost flow problem, 2)minimum-cost flow problem by the mathematical equivalent and 3) extraction $\varepsilon$-relaxation & expand transfer problem with minimum-cost flow. It can be applicant to PCB design by above mentioned.

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Maximum Capacity-based Minimum Cut Algorithm (최대 수용량-기반 최소절단 알고리즘)

  • Lee, Sang-Un
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.5
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    • pp.153-162
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    • 2011
  • The minimum cut problem is to minimize c(S,T), that is, to determine source S and sink T such that the capacity of the S-T cut is minimal. The flow-based algorithm is mostly used to find the bottleneck arcs by calculating flow network, and does not presents the minimum cut. This paper suggests an algorithm that simply includes the maximum capacity vertex to adjacent set S or T and finds the minimum cut without obtaining flow network in advance. On applying the suggested algorithm to 13 limited graphs, it can be finds the minimum cut value $_{\min}c$(S, T) with simply and correctly.

액막류의 MHF점에 관한 실험적 연구

  • 김영찬;서태원
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.10
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    • pp.960-965
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    • 2001
  • The minimum heat flux conditions are experimentally investigated for the subcooled liquid film flow on the horizontal plate. The experimental results show that the minimum heat flux point temperature becomes higher with the increase of the velocity and the subcooling of the liquid film flow. However, the effect of distance from the leading edge of the heat transfer plate on the minimum heat flux is almost negligible. Also, the experimental results show that the propagation velocity of wetting front increases with increasing the velocity and the subcooling of the liquid film flow.

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Study on Minimum Heat Flux Point in Spray Cooling of Hot Plate (고온 강판의 분무냉각에 있어서 MHF 점에 관한 연구)

  • Kim, Yeung-Chan
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.175-180
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    • 2001
  • In this study, the minimum heat flux conditions are experimentally investigated for the spray cooling of hot plate. The hot plates are cooled down from the initial temperature of about $900^{\circ}C$, and the local heat flux and surface temperatures are calculated from the measured temperature-time history. The results show that the minimum heat flux point temperatures increase linearly resulting from the propagation of wetting front with the increase of the distance from the stagnation point of spray flow. However, in the wall region, the minimum heat flux point temperature becomes independent of the distance. Also, the experimental results show that the velocity of wetting front increases with the increase of the droplet flow rate.

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