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A RECOGNITION PROBLEM IN CONVERTING LINEAR PROGRAMMING TO network flow MODELS

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Applied Mathematics(A Journal of Chinese Universities) 1993年第1期8卷 76-85页

作者：林诒勋 Department of Mathematics ZhengzhouUniversity Zhengzhou 450052

The main goal of this paper is to study the following combinatorial problem : given a finite set E = (e1, e2, ...,em} and a subset family a - [S1,S2, ... ,Sk} of E , does there exist a tree T with the edge set E such ... 详细信息

关键词： Linear Programming network flow Polygon-matrix Sequencing Tree.

Role Recognition Method Based on network flow Characteristics

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Role Recognition Method Based on Network Flow Characteristic...

BLOCKING CUTSET OF A network AND ITS DETERMINATION (Ⅱ) Research on the Blocking flow in a Transport network

作者： Tao YU Rui-qi YUE Beijing Institute of Tracking and Telecommunications Technology Science and Technology on Information Systems Engineering Laboratory National University of DT

network user behavior analysis is very important for the security of large organizations’ intranet. In order to analyze the behavior of Intranet users, it is necessary to identify the roles of Intranet users. In this paper, a role recognition method based on network flow characteristics is proposed for organizational intranet, which is a specific network space. Firstly, the interactive distribution characteristics of network flow based on information entropy are used to describe the distribution characteristics of different network nodes. Secondly, traffic characteristics are used to analyze the interaction flow between nodes. Finally, based on these feature sets, Stochastic Forest method is applied to recognize the role of intranet. Experiments on real intranet data verify the effectiveness of the proposed method.

关键词： Intranet security network flow Organizational role Random forest

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Transactions of Nanjing University of Aeronautics and Astronautics 1996年第1期13卷 100-104页

作者： Ning Xuanxi Industry and Business College, NUAA29 Yudao Street,Nanjing 210016, P. R .China

ransport network in the paper is defined as follows: (1) Connected and directed network without self loop;(2) There is only one source vertex with zero in degree; (3) There is only one sink vertex with zero out degree;(4) The capacity of every arc is non negative integer Blocking flow is a kind of flow commonly happened in a transport network . Its formation is due to the existance of a blocking cutset in the network. In this paper the fundamental concepts and theorems of the blocking flow and the blocking cutset are introduced and a linear programming model for determining the blocking cutset in a network is set up. In order to solve the problem by graph theoretical approach a method called 'two way flow augmenting algorithm' is developed. With this method an iterative procedure of forward and backward flow augmenting process is used to determine whether a given cutset is a blocking one.

关键词： graph theory maximum flow network analysis blocking flow network flow

Constrained Newton Methods for Transport network Equilibrium Analysis

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Tsinghua Science and Technology 2009年第6期14卷 765-775页

作者：程琳许项东邱松林 School of Transportation Southeast University

A set of constrained Newton methods were developed for static traffic assignment problems. The Newton formula uses the gradient of the objective function to determine an improved feasible direction scaled by the second-order derivatives of the objective function. The column generation produces the active paths necessary for each origin-destination pair. These methods then select an optimal step size or make an orthogonal projection to achieve fast, accurate convergence. These Newton methods based on the constrained Newton formula utilize path information to explicitly implement Wardrop＇s principle in the transport network modelling and complement the traffic assignment algorithms. Numerical examples are presented to compare the performance with all possible Newton methods. The computational results show that the optimal-step Newton methods have much better convergence than the fixed-step ones, while the Newton method with the unit step size is not always efficient for traffic assignment problems. Furthermore, the optimal-step Newton methods are relatively robust for all three of the tested benchmark networks of traffic assignment problems.

关键词： traffic assignment network flow Newton method column generation line search

THE APPLICATION OF THE BRANCH AND BOUND METHOD FOR DETERMINING THE MINIMUM flow OF A TRANSPORT network

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Transactions of Nanjing University of Aeronautics and Astronautics 1996年第2期13卷 45+41-44页

作者：宁宣熙南京航空航天大学工商学院

Blockage is a kind of phenomenon frequently occurred in a transport network, in which the human beings are the moving subjects. The minimum flow of a network defined in this paper means the maximum flow quantity through the network in the seriously blocked situation. It is an important parameter in designing and operating a transport network, especially in an emergency evacuation network. A branch and bound method is presented to solve the minimum flow problem on the basis of the blocking flow theory and the algorithm and its application are illustrated by examples.

关键词： network flow graph theory network programming minimum flow blocking flow

Exploring the Constrained Maximum Edge-weight Connected Graph Problem

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Acta Mathematicae Applicatae Sinica 2009年第4期25卷 697-708页

作者： Zhen-ping Li Shi-hua Zhang Xiang-Sun Zhang Luo-nan Chen School of Information Beijing Wuzi University Beijing 101149 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China Institute of Systems Biology Shanghai University Shanghai 200444 China Department of Electrical Engineering and Electronics Osaka Sangyo University Osaka 574-8530 Japan

Given an edge weighted graph, the maximum edge-weight connected graph （MECG） is a connected subgraph with a given number of edges and the maximal weight sum. Here we study a special case, i.e. the Constrained Maximum Edge-Weight Connected Graph problem （CMECG）, which is an MECG whose candidate subgraphs must include a given set of k edges, then also called the k-CMECG. We formulate the k-CMECG into an integer linear programming model based on the network flow problem. The k-CMECG is proved to be NP-hard. For the special case 1-CMECG, we propose an exact algorithm and a heuristic algorithm respectively. We also propose a heuristic algorithm for the k-CMECG problem. Some simulations have been done to analyze the quality of these algorithms. Moreover, we show that the algorithm for 1-CMECG problem can lead to the solution of the general MECG problem.

关键词： connected subgraph integer linear programming model network flow constraint Steiner network maximum edge weight, heuristic algorithm

Optimal flow conditions of a tracheobronchial model to reengineer lung structures

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Acta Mechanica Sinica 2017年第2期33卷 284-294页

作者： Stefano Casarin Federico Aletti Giuseppe Baselli Marc Garbey LASIE UMR CNTS Univeristy of La Rochelle La Rochelle France Houston Methodist Hospital Research Institute Houston TX USA Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano Milan Italy

The high demand for lung transplants cannot be matched by an adequate number of lungs from donors. Since fully ex-novo lungs are far from being feasible, tissue engineering is actively considering implantation of engineered lungs where the devitalized structure of a donor is used as scaffold to be repopulated by stem cells of the receiving patient. A decellularized donated lung is treated inside a bioreactor where transport through the tracheobronchial tree (TBT) will allow for both deposition of stem cells and nourishment for their subsequent growth, thus developing new lung tissue. The key concern is to set optimally the boundary conditions to utilize in the bioreactor. We propose a predictive model of slow liquid ventilation, which combines a one-dimensional (1-D) mathematical model of the TBT and a solute deposition model strongly dependent on fluid velocity across the tree. With it, we were able to track and drive the concentration of a generic solute across the airways, looking for its optimal distribution. This was given by properly adjusting the pumps’ regime serving the bioreactor. A feedback system, created by coupling the two models, allowed us to derive the optimal pattern. The TBT model can be easily invertible, thus yielding a straightforward flow/pressure law at the inlet to optimize the efficiency of the bioreactor.

关键词： Bioreactor Lung rehabilitation network flow Tissue engineering Transport of solute

Optimal operation of cascaded hydroelectric power plants in the power market

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Journal of Harbin Institute of Technology(New Series) 2004年第6期11卷 614-617页

作者：蔡兴国马平林士颖 Dept. of Electric Engineering Harbin Institute of Technology Harbin 150001 China

An improved network flow algorithm, which includes the minimum cost network flow and the same period network flow, is proposed to solve the optimization of cascaded hydroelectric power plants in a competitive electricity market. The typical network flow is used to find the feasible flow and add the discharge water to different cascaded hydroelectric power plants at the same step. The same period network flow is used to find the optimal flow and add the power output at a different step. This new algorithm retains the advantages of the typical network flow, such as simplicity and ease of realization. The result of the case analysis indicates that the new algorithm can achieve high calculation precision and can be used to calculate the optimal operation of cascaded hydroelectric power plants.

关键词： cascaded hydroelectric power plants network flow market clearing price

A New Algorithm for the Weighted Reliability of networks

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The Journal of China Universities of Posts and Telecommunications 2000年第3期7卷 38-43,47页

作者： LIU Chen (Nanjing University of Posts and Telecomunications,Nanjing 210003,P.R.China) Nanjing University of Posts and Telecomunications Nanjing 210003 P. R. China

The weighted reliability of network is defined as the sum of the multiplication of the probability of each network state by its normalized weighting *** a certain state, when the capacity from source s to sink t is larger than the given required capacity C r, then the normalized weighting factor is 1, otherwise, it is the ratio of the capacity to the required capacity C r. This paper proposes a new algorithm for the weighted reliability of networks, puts forward the concept of saturated state of capacity, and suggests a recursive formula for expanding the minimal paths to be the sum of qualifying subsets. In the new algorithm, the expansions of the minimal paths dont create the irrelevant qualifying subsets, thus decreasing the unnecessary expanding calculation. Compared with the current algorithms, this algorithm has the advantage of a small amount of computations for computer implementation.

关键词： weighted reliability capacity minimal paths network flow