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DETECTING COMMUNITY STRUCTURE： FROM PARSIMONY TO WEIGHTED PARSIMONY

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Journal of Systems Science & Complexity 2010年第5期23卷 1024-1036页

作者： Junhua zhang Yuqing QIU xiang-sun zhang Key Laboratory of Random Complex Structures and Data Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Community detection has attracted a great deal of attention in recent years. A parsimony criterion for detecting this structure means that as minimal as possible number of inserted and deleted edges is needed when we make the network considered become a disjoint union of cliques. However, many small groups of nodes are obtained by directly using this criterion to some networks especially for sparse ones. In this paper we propose a weighted parsimony model in which a weight coefficient is introduced to balance the inserted and deleted edges to ensure the obtained subgraphs to be reasonable communities. Some benchmark testing examples are used to validate the effectiveness of the proposed method. It is interesting that the weight here can be determined only by the topological features of the network. Meanwhile we make some comparison of our model with maximizing modularity Q and modularity density D on some of the benchmark networks, although sometimes too many or a little less numbers of communities are obtained with Q or D, a proper number of communities are detected with the weighted model. All the computational results confirm its capability for community detection for the small or middle size networks.

关键词： Cliques community detection complex networks parsimony.

Coordinating Pricing and Inventory Control in a Fluctuating Environment

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Acta Mathematicae Applicatae Sinica 2010年第2期26卷 187-204页

作者： Ju-liang zhang Jian Chen xiang-sun zhang Department of Logistics Management School of Economics and Management Beijing Jiaotong UniversityBeijing 100044 China Department of Management Science and Engineering School of Economics and Management Tsinghua Uni-versity Beijing 100084 China Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sci-ences Beijing 100190 China

This paper addresses the simultaneous determination of pricing and inventory replenishment strate- gies under a fluctuating environment. Specifically, we analyze the single item, periodic review model. The demand consists of two parts： the deterministic component, which is influenced by the price, and the stochastic component （perturbation）. The distribution of the stochastic component is determined by the current state of an exogenous Markov chain. The price that is charged in any given period can be specified dynamically. A replenishment order may be placed at the beginning of some or all of the periods, and stockouts are fully backlogged. Ordering costs that are lower semicontinuous, and inventory/backlog （or surplus） costs that are continuous with polynomial growth. Finite-horizon and infinite-horizon problems are addressed. Existence of optimal policies is established. Furthermore, optimality of （s,S,p）-type policies is proved when the ordering cost consists of fixed and proportional cost components and the surplus cost （these costs are all state-dependent） is convex.

关键词： Stochastic inventory management Markov chains pricing finite horizon infinite horizon

SELF-ORGANIZING MAP OF COMPLEX NETWORKS FOR COMMUNITY DETECTION

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Journal of Systems Science & Complexity 2010年第5期23卷 931-941页

作者： Zhenping LI Ruisheng WANG xiang-sun zhang Luonan CHEN School of Information Beijing Wuzi University Beijing 101149 China School of Information Renmin University of China Beijing 100872 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Department of Electrical Engineering and Electronics Osaka Sangyo University Osaka 574-8530 Japan

Detecting communities from complex networks is an important issue and has attracted attention of researchers in many fields. It is relevant to social tasks, biological inquiries, and technological problems since various networks exist in these systems. This paper proposes a new self-organizing map （SOM） based approach to community detection. By adopting a new operation and a new weightupdating scheme, a complex network can be organized into dense subgraphs according to the topological connection of each node by the SOM algorithm. Extensive numerical experiments show that the performance of the SOM algorithm is good. It can identify communities more accurately than existing methods. This method can be used to detect communities not only in undirected networks, but also in directed networks and bipartite networks.

关键词： Community detection complex network neural networks self-organizing map.

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

GOMA:functional enrichment analysis tool based on GO modules

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Chinese Journal of Cancer 2013年第4期32卷 195-204页

作者： Qiang Huang Ling-Yun Wu Yong Wang xiang-sun zhang National Center for Mathematics and Interdisciplinary Sciences Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences

Analyzing the function of gene sets is a critical step in interpreting the results of high-throughput experiments in systems biology. A variety of enrichment analysis tools have been developed in recent years, but most output a long list of significantly enriched terms that are often redundant, making it difficult to extract the most meaningful functions. In this paper, we present GOMA, a novel enrichment analysis method based on the new concept of enriched functional Gene Ontology (GO) modules. With this method, we systematically revealed functional GO modules, i.e., groups of functionally similar GO terms, via an optimization model and then ranked them by enrichment scores. Our new method simplifies enrichment analysis results by reducing redundancy, thereby preventing inconsistent enrichment results among functionally similar terms and providing more biologically meaningful results.

关键词： GO enrichment analysis, modules, functional redundancy, network, relationships

A Dynamic Programming Algorithm for the κ-Haplotyping Problem

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Acta Mathematicae Applicatae Sinica 2006年第3期22卷 405-412页

作者： Zhen-ping Li Ling-yun Wu Yu-ying Zhao xiang-sun zhang Institute of Applied Mathematics Academy of Mathematics and Systems Science CAS Beijing 100080 China Mathematics Department of Beijing Wuzi University Beijing 101149 China Mathematics Department of Beijing Forest University Beijing China

The Minimum Fragments Removal （MFR） problem is one of the haplotyping problems： given a set of fragments, remove the minimum number of fragments so that the resulting fragments can be partitioned into k classes of non-conflicting subsets. In this paper, we formulate the κ-MFR problem as an integer linear programming problem, and develop a dynamic programming approach to solve the κ-MFR problem for both the gapless and gap eases.

关键词： Integer programming dynamic programming κ-haplotyping SNP

Design method of extractant for liquid-liquid extraction based on elements and chemical bonds

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Chinese Journal of Chemical Engineering 2024年第4期68卷 193-202页

作者： Yuwen Wei Chunling zhang Yue zhang Lili Wang Li Xia Xiaoyan sun Shuguang xiang Institute of Process System Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Yantai Guobang Chemical Machinery Technology Co. Ltd.Yantai 264002China

In the petrochemical industry process, the relative volatility between the components to be separated is close to one or the azeotrope that systems are difficult to separate. Liquid-liquid extraction is a common and effective separation method, and selecting an extraction agent is the key to extraction technology research. In this paper, a design method of extractants based on elements and chemical bonds was proposed. A knowledge-based molecular design method was adopted to pre-select elements and chemical bond groups. The molecules were automatically synthesized according to specific combination rules to avoid the problem of “combination explosion” of molecules. The target properties of the extractant were set, and the extractant meeting the requirements was selected by predicting the correlation physical properties of the generated molecules. Based on the separation performance of the extractant in liquid-liquid extraction and the relative importance of each index, the fuzzy comprehensive evaluation membership function was established, the analytic hierarchy process determined the mass ratio of each index, and the consistency test results were passed. The results of case study based on quantum chemical analysis demonstrated that effective determination of extractants for the analysis of benzene-cyclohexane systems. The results unanimously prove that the method has important theoretical significance and application value.

关键词： Molecular design Element and chemical bonds Molecular simulation Thermodynamics Solvent extraction

Temperature prediction model in multiphase flow considering phase transition in the drilling operations

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Petroleum Science 2024年第3期21卷 1969-1979页

作者： Yang zhang Yong-An Li xiang-Wei Kong Hao Liu Teng-Fei sun College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100027China School of Petroleum Engineering Yangtze UniversityWuhan430000HubeiChina

The study considers gas compression properties,gas slippage,back pressure(BP),phase transition(PT),well depth,and differences in gas-liquid physical properties.A new temperature model for multiphase flow is proposed by considering phase transition in the drilling *** mathematical model of multiphase flow is solved using the finite difference method with annulus mesh division for grid nodes,and a module for multiphase flow calculation and analysis is *** results indicate that the temperature varies along the annulus with the variation of gas influx at the bottom of the *** the process of controlled pressure drilling,as gas slips along the annulus to the wellhead,its volume continuously expands,leading to an increase in the gas content within the annulus,and consequently,an increase in the pressure drop caused by gas *** temperature increases with the increase in BP and decreases in gas influx rate and wellbore *** gas influx,the thermal conductivity coefficient for the gas-drilling mud two phases is significantly weakened,resulting in a considerable change in temperature along the *** the context of MPD,the method of slightly changing the temperature along the annulus by controlling the back pressure is feasible.

关键词： Managed pressure drilling Phase transition Temperature Gas-drilling mud two phase

Feasible Synthesis of N,O-Bidentate Difluoroboron Chromophores through Direct Functionalization of Quinoxalin-2(1H)-ones with Ketones in One Shot

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Chinese Journal of Chemistry 2024年第13期42卷 1481-1486页

作者： Shuaichen zhang Jing zhang xiang Ling Yifan Zhao Yue Ma Peng sun State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs Artemisinin Research Center and Institute of Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijing 100700China Department of Pharmaceutics School of PharmacyChina Pharmaceutical UniversityState Key Laboratory of Natural MedicinesNanjingJiangsu 210009China

Organic difluoroboron complexes are a kind of potential platforms for a wide range of applications owing to their excellent photophysical ***,we have explored a simple and direct synthesis methodology for a library of N,O-bidentate difluoroboron complexes from quinoxalin-2(1H)-ones and ketones in one *** photophysical properties of the generated complexes were evaluated and the application potential of these compounds on subcellular imaging was also explored.

关键词： N,O-Bidentate difluoroboron Chromophores Quinoxalin-2(1H)-ones Ketones/Green chemistry Synthetic method C-CcouplingI Boron