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Nowhere-zero 3-flows in Cayley graphs on generalized dihedral group and generalized quaternion group

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Frontiers of Mathematics in China 2015年第2期10卷 293-302页

作者： liangchen LI Xiangwen LI Department of Mathematics Huazhong Normal University Wuhan 430079 China Department of Mathematics Luoyang Normal University Luoyang 471022 China

Tutte conjectured that every 4-edge-connected graph admits a nowhere-zero 3-flow. In this paper, we show that this conjecture is true for Cayley graph on generalized dihedral groups and generalized quaternion groups, which generalizes the result of F. Yang and X. Li [Inform. Process. Lett., 2011, 111： 416-419]. We also generalizes an early result of M. Nanasiova and M. Skoviera [J. Algebraic Combin., 2009, 30： 103-110].

关键词： Nowhere-zero 3-flow Cayley graph generalized dihedral group,generalized quaternion group

Global Dynamics of a Quasilinear Chemotaxis System with Indirect Signal Production and Generalized Logistic Source

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Wuhan University Journal of Natural Sciences 2021年第5期26卷 369-375页

作者： YE Xiaobing WANG liangchen School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China

This paper considers the following quasilinear chemo-taxis system with indirect signal production and generalized logistic source{u_(t)=▽·(▽(u)▽u)-▽·(S(u)▽v)+μ(u-u^(Y)),x∈Ω,t>0 O=△v-v+w,x∈Ω,t>0 w_(t)=-δw+u,x∈Ω,t>0 under homogeneous Neumann boundary conditions in a smooth bounded domainΩ■R^(n)(n≥1),where the parametersμ,δ>0 andγ>1,the functions D(u)and S(u)are supposed to be smooth fulfilling D(u)≥C_(D)(u+1)^(-a)and S(u)≤C_(S)u(u+1)^(β-1)for all u≥0 with C D,α,β∈R *** is proved that the corresponding initial-boundary value problem possesses a global bounded classical solution ifα+2β<γ-***,ifμis suitably large,the asymptotic behavior and convergence rates are also been considered.

关键词： chemotaxis boundedness generalized logistic source indirect signal production

Max-Flow Problem in Undirected Planar Networks with Node Capacities Being in NC

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Journal of Computer Science & Technology 2004年第6期19卷 787-790页

作者： Xian-ChaoZhang Ying-YuWan Guo-liangchen NationalHighPerformanceComputingCenteratHefei DepartmentofComputerScienceandTechnologyUniversityofScienceandTechnologyofChinaHefei230027P.R.China

The max-flow problem in planar networks with only edge capacities has been proved to be in NC (Nickle's Class). This paper considers a more general version of the problem when the nodes as well as the edges have capacities. In a general network, the node-edge-capacity problem can be easily reduced to the edge-capacity problem. But in the case of planar network this reduction may destroy the planarity, and reduces the problem to the edge-capacity problem in a general network, which is P-complete. A recent contribution presents a new reduction for planar networks, that maintains the planarity. In this paper, it is proved that this reduction is in NC and thus the node-edge-capacity problem in undirected planar networks is in NC. Keywords parallel algorithm - NC (Nickle's Class) algorithm, max-flow Supported by the National Basic Research 973 Program of China under Grant No.G1999032700.

关键词： parallel algorithm NC (Nickle's Class) algorithm, max-flow

New Meta-Heuristic for Combinatorial Optimization Problems：Intersection Based Scaling

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Journal of Computer Science & Technology 2004年第6期19卷 740-751页

作者： PengZou ZhiZhou Ying-YuWan Guo-liangchen JunGu DepartmentofComputerScienceandTechnology Universityo／ScienceandTechnologyo／ChinaNationalHighPerformanceComputingCenteratHefeiHefei230027P.R.China DepartmentofComputerScience HongKongUniversityofScienceandTechnologyHongKongSpecialAdministrativeRegionP.R.China

Combinatorial optimization problems are found in many application fields such as computer science, engineering and economy. In this paper, a new efficient meta-heuristic, Intersection-Based Scaling (IBS for abbreviation), is proposed and it can be applied to the combinatorial optimization problems. The main idea of IBS is to scale the size of the instance based on the intersection of some local optima, and to simplify the search space by extracting the intersection from the instance, which makes the search more efficient. The combination of IBS with some local search heuristics of different combinatorial optimization problems such as Traveling Salesman Problem (TSP) and Graph Partitioning Problem (GPP) is studied, and comparisons are made with some of the best heuristic algorithms and meta-heuristic algorithms. It is found that it has significantly improved the performance of existing local search heuristics and significantly outperforms the known best algorithms. Keywords combinatorial optimization - TSP (Traveling Salesman Problem) - GPP (Graph Partitioning Problem) - IBS (Intersection-Based Scaling) - meta heuristic Regular PaperThis work is supported by the National Basic Research 973 Program of China (Grant ***1998030401).Peng Zou was born in 1979. He received the B.S. degree in computer software from University of Science and Technology of China (USTC) in 2000. Now he is a Ph.D. candidate in computer science of USTC. His current research interests include algorithms for NP-hard problems and parallel computing.Zhi Zhou was born in 1976. He received the B.S. degree in computer software from USTC in 1995. Now he is a Ph.D. candidate in computer science of USTC. His current research interests include combinatorial problem and parallel computing.Ying-Yu Wan was born in 1976. He received the B.S. degree in computer software from USTC in 1997, and the Ph.D. degree from USTC in 2002. His current research interests include parallel computing and combinat

关键词： combinatorial optimization TSP (Traveling Salesman Problem) GPP (Graph Partitioning Problem) IBS (Intersection-Based Scaling) meta heuristic

RSAD： A Robust Distributed Contention-Based Adaptive Mechanism for IEEE 802.11 Wireless LANs

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Journal of Computer Science & Technology 2005年第2期20卷 282-288页

作者： YongPeng Shi-DuanCheng Jun-liangchen NationalLaboratoryofSwitchingTechnologyandTelecommunicationNetworksBeijingUniversityofPostsandTelecommunications Beijing100876P.R.China

Previous researches have shown that Distributed Coordination Function (DCF) access mode of IEEE 802.11 has lower performance in heavy contention environment. Based on the in-depth analysis of IEEE 802.11 DCF, NSAD (New Self-adapt DCF-based protocol) has been proposed to improve system saturation-throughput in heavy contention condition. The initial contention window tuning algorithm of NSAD is proved effective in error-free environment. However, problems concerning the exchanging of initial contention window occur in error-prone environment. Based on the analysis of NSAD's performance in error-prone environment, RSAD is proposed to further enhance the performance. Simulation in a more real shadowing error-prone environment is done to compare the performance of NSAD and RSAD and results have shown that RSAD can achieve further performance improvement as expected in the-error-prone environment than NSAD (i.e., better goodput and fairness index).

关键词： distributed coordination function (DCF) wireless LAN (WLAN) performance enhancement robust

Folding and everting distal end of graft flap to reduce orifice stenosis following onlay urethroplasty

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Asian Journal of Andrology 2003年第2期5卷 159-161页

作者： RuiJIANG Jiang-HuaCHEN Hong-WeiLI Tong-liangchen KidneyDiseasesCenter FirstAffiliatedHospitalZhejiangUniversityMedicalCollegeHangzhou310003China DepartmentofUrology AffiliatedHospitalLuzhouMedicalCollegeLuzhou646000China

Aim: Orifice stenosis remained to be a common complication of hypospadias repair. We had modified the preputial island flap urethroplasty by folding and everting the distal end of the pedicle graft flap to prevent the neoorifice from stenosis. Methods: Sixteen patients had undergone hypospadias repair using a modified onlay island flap technique. A urethral catheter was retained for 8 days to 10 days after operation. Results: Satisfactory results were seen in all the patients with a cosmetically fine appearance. One patient had a urinary tract infection and another, urethrocutaneous fistula and both were amply treated. No glanular adhesion or stenosis occurred. A long-term follow up of 6 months to 4 years (mean: 2 years) in 15 patients did not find any complication. Conclusion: The modified preputial island flap urethroplasty technique is an easy, reliable and effective approach to reduce orifice stenosis in hypospadias repair.

关键词： hypospadias urethra complications

Toward better understanding vacuum ultraviolet-iodide induced photolysis via hydrogen peroxide formation,iodine species change,and difluoroacetic acid degradation

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Frontiers of Environmental Science & Engineering 2022年第5期16卷 3-12页

作者： Yang Yang Qi Zhang Baiyang Chen liangchen Long Guan Zhang State Key Laboratory of Urban Water Resource and Environment Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Recently,a photochemical process induced by ultraviolet(UV),vacuum UV(VUV),and iodide(I–)has gained attention for its robust potential for contaminant ***,the mechanisms behind this process remain unclear because both oxidizing and reducing reactants are likely *** better understand this process,this study examined the evolutions of hydrogen peroxide(H_(2)O_(2))and iodine species(i.e.,iodide,iodate,and triiodide)during the UV/VUV/I–process under varying pH and dissolved oxygen(DO)*** show that increasing DO in water enhanced H2O2 and iodate production,suggesting that high DO favors the formation of oxidizing *** contrast,increasing pH(from 6.0 to 11.0)resulted in lower H_(2)O_(2) and iodate formation,indicating that there was a decrease of oxidative capacity for the UV/VUV/I–*** addition,difluoroacetic acid(DFAA)was used as an exemplar contaminant to verify above *** its degradation kinetics did not follow a constant trend as pH increases,the relative importance of mineralization appeared declining,suggesting that there was a redox transition from an oxidizing environment to a reducing environment as pH *** treatability of the UV/VUV/I–process was stronger than UV/VUV under pH of 11.0,while UV/VUV process presented a better performance at pH lower than 11.0.

关键词： Vacuum ultraviolet Hydrogen peroxide Iodate Hydroxyl radical Redox transition

FEW-NNN: A Fuzzy Entropy Weighted Natural Nearest Neighbor Method for Flow-Based Network Traffic Attack Detection

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China Communications 2020年第5期17卷 151-167页

作者： liangchen Chen Shu Gao Baoxu Liu Zhigang Lu Zhengwei Jiang School of Computer Science and Technology Wuhan University of TechnologyWuhan 430063China Institute of Information Engineering Chinese Academy of SciencesBeijing 100093China School of Applied Technology China University of Labor RelationsBeijing 100048China School of Cyber Security University of Chinese Academy of SciencesBeijing 100049China

Attacks such as APT usually hide communication data in massive legitimate network traffic, and mining structurally complex and latent relationships among flow-based network traffic to detect attacks has become the focus of many initiatives. Effectively analyzing massive network security data with high dimensions for suspicious flow diagnosis is a huge challenge. In addition, the uneven distribution of network traffic does not fully reflect the differences of class sample features, resulting in the low accuracy of attack detection. To solve these problems, a novel approach called the fuzzy entropy weighted natural nearest neighbor(FEW-NNN) method is proposed to enhance the accuracy and efficiency of flowbased network traffic attack detection. First, the FEW-NNN method uses the Fisher score and deep graph feature learning algorithm to remove unimportant features and reduce the data dimension. Then, according to the proposed natural nearest neighbor searching algorithm(NNN_Searching), the density of data points, each class center and the smallest enclosing sphere radius are determined correspondingly. Finally, a fuzzy entropy weighted KNN classification method based on affinity is proposed, which mainly includes the following three steps: 1、 the feature weights of samples are calculated based on fuzzy entropy values, 2、 the fuzzy memberships of samples are determined based on affinity among samples, and 3、 K-neighbors are selected according to the class-conditional weighted Euclidean distance, the fuzzy membership value of the testing sample is calculated based on the membership of k-neighbors, and then all testing samples are classified according to the fuzzy membership value of the samples belonging to each class;that is, the attack type is determined. The method has been applied to the problem of attack detection and validated based on the famous KDD99 and CICIDS-2017 datasets. From the experimental results shown in this paper, it is observed that the FEW-NNN method

关键词： fuzzy entropy weighted KNN network attack detection fuzzy membership natural nearest neighbor network security intrusion detection system

CSES GNSS ionospheric inversion technique, validation and error analysis

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Science China(Technological Sciences) 2018年第5期61卷 669-677页

作者： LIN Jian SHEN XuHui HU liangchen WANG LanWei ZHU FuYing Key Laboratory of Earthquake Geodesy Institute of SeismologyChina Earthquake Administration Institute of Crustal Dynamics China Earthquake Administration

With the increased number of low Earth orbit(LEO) satellites equipped with global navigation satellite system(GNSS) receiver,the LEO based GNSS slant total electron content(TEC) and electron density profile(EDP) data play an increasingly important role in space weather and ionospheric research due to improved global coverage. China Seismo-Electromagnetic Satellite(CSES), which was launched in February 2018, is equipped with GNSS receiver for either precise orbit determination(POD) and ionospheric inversion. The purpose of the present paper is to validate CSES GNSS ionospheric inversion technique based on the real observations and verify the accuracy of TEC and EDP retrieval based on the simulated data. The following conclusions can be drawn: the epoch difference inversion(EDI) derived from CSES can successfully retrieve the EDPs without non-occultation side measurements; the technique of EDI and the calibrated TEC inversion(CTI) have similar behaviors in inversion errors,however, the retrieved Nm F2 and hm F2 have a larger systematic error surrounding the equatorial ionization anomaly(EIA)where the assumption of spherical symmetry is often invalid; the precision and accuracy of retrieved TEC have been investigated in the paper based on the simulated data, and it is found that the accuracy of the retrieved TEC is relative to solar activity: the lower the F10.7 index, the higher the accuracy of retrieved TEC.

关键词： China Seismo-Electromagnetic Satellite global navigation satellite system total electron content electron density profile