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Distances Between Phylogenetic Trees: A Survey

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Tsinghua Science and Technology 2013年第5期18卷 490-499页

作者： Feng Shi Qilong Feng Jianer Chen Lusheng wang jianxin wang School of Information Science and Engineering Central South University Department of Computer Science and Engineering Texas A&M University College Station Department of Computer Science City University of Hong Kong

Phylogenetic trees have been widely used in the study of evolutionary biology for representing the tree-like evolution of a collection of species. However, different data sets and different methods often lead to the construction of different phylogenetic trees for the same set of species. Therefore, comparing these trees to determine similarities or, equivalently, dissimilarities, becomes the fundamental issue. Typically, Tree Bisection and Reconnection（TBR）and Subtree Prune and Regraft（SPR） distances have been proposed to facilitate the comparison between different phylogenetic trees. In this paper, we give a survey on the aspects of computational complexity, fixed-parameter algorithms, and approximation algorithms for computing the TBR and SPR distances of phylogenetic trees.

关键词： phylogenetic tree tree bisection and reconnection subtree prune and regraft fixed-parameter algorithm approximation algorithm

Analysis of SF6 decomposed products by fibre-enhanced Raman spectroscopy for gas-insulated switchgear diagnosis

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High Voltage 2024年第1期9卷 206-216页

作者： jianxin wang Weigen Chen Pinyi wang Fu Wan Zhixian Zhang Shoufei Gao Yingying wang School of Electrical Engineering Chongqing UniversityChongqingChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina Institute of Photonics Technology Jinan UniversityGuangzhouChina

Sulphur hexafluoride(SF6)decomposed products analysis is highly critical in the earlystage fault diagnosis of gas-insulated switchgear(GIS).Spectrum technology outperforms traditional methods on non-invasiveness,no sample preparation,and no ***,the authors present an improved fibre-enhanced Raman spectroscopy(FERS)as a comprehensive analytical tool to detect a suite of SF_(6)decomposed products(SO_(2)F_(2),SOF_(2),SO_(2),H_(2)S,CF_(4),OCS,CO_(2),and CO).The FERS approach is combined with two iris diaphragms for spatial filtering and a rear-end reflector for additional Raman signal *** of detection down to 1×10^(−6)–8×10^(−6)are achieved for different SF6 decompositions,and quantification of an undefined multigas,sampled from an 800 kV GIS in service,is realised utilising SF6 as the internal standard gas and with a maximum error of 5.5%.The GIS is diagnosed according to the results and confirmed by an on-site *** authors foresee that this technique will provide a route for trace gas analysis in the power industry.

关键词： SF6 diagnosis fibre

Construction of Low Delay Maximal Rate Single-Symbol Decodable Distributed STBC with Channel Phase Information

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Transactions of Nanjing University of Aeronautics and Astronautics 2016年第6期33卷 -页

作者： Chen Junsheng Zhang Xiaofei Shu Feng wang jianxin College of Information Engineering Yangzhou University School of Electronic and Optical Engineering Nanjing University of Science and Technology College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics National Mobile Communications Research Laboratory Southeast University

Exploiting the source-to-relay channel phase information at the relays can increase the rate upper-bound of distributed orthogonal space-time block codes(STBC)from 2/K to 1/2,where Kis the number of *** technique is known as distributed orthogonal space-time block codes with channel phase information(DOSTBC-CPI).However,the decoding delay of existing DOSTBC-CPIs is not ***,based on the rate of 1/2 balanced complex orthogonal design(COD),an algorithm is provided to construct a maximal rate DOSTBC-CPI with only half the decoding delay of existing *** results show that the proposed method exhibits lower symbol error rate than the existing DOSTBC-CPIs.

关键词： distributed STBC channel phase information decoding delay single-symbol decoding

An approximation algorithm for k-median with priorities

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Science China(Information Sciences) 2021年第5期64卷 45-46页

作者： Zhen ZHANG Qilong FENG Jinhui XU jianxin wang School of Computer Science and Engineering Central South University Department of Computer Science and Engineering State University of New York at Buffalo

Dear editor,Clustering is a fundamental problem in computer *** problem is to partition a given set of clients into several clusters such that clients in the same cluster are more similar to each other. In many clustering applications, the clients are different in the levels of services they require. Motivated by such applications, Ravi and Sinha [1] introduced the problem of clustering with priorities, wherein each client is associated with a priority and can only be assigned to a facility opened at the same or higher priorities.

关键词： Clustering k median approximation algorithm LP relaxtion primal-dual

On the parameterized vertex cover problem for graphs with perfect matching

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Science China(Information Sciences) 2014年第7期57卷 105-116页

作者： wang jianxin LI WenJun LI ShaoHua CHEN JianEr School of Information Science and Engineering Central South University Department of Computer Science and Engineering Texas A&M UniversityCollege Station

A vertex cover of an n-vertex graph with perfect matching contains at least n/2 *** this paper,we study the parameterized complexity of the problem vc-pm*that decides if a given graph with perfect matching has a vertex cover of size bounded by n/2+*** first present an algorithm of running time O*(4k)for a variation of the vertex cover problem on K¨onig graphs with perfect *** algorithm combined with the iterative compression technique leads to an algorithm of running time O*(9k)for the problem vc-pm*.Our result improves the previous best algorithm of running time O*(15k)for the vc-pm*problem,which reduces the problem to the almost 2-sat problem and solves the latter by Razgon and O’Sullivan’s recent algorithm.

关键词： NP-complete parameterized algorithm vertex cover iterative compression

A Feature Selection Method for Prediction Essential Protein

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Tsinghua Science and Technology 2015年第5期20卷 491-499页

作者： Jiancheng Zhong jianxin wang Wei Peng Zhen Zhang Min Li the School of Information Science and Engineering Central South University the College of Polytechnic Hunan Normal University the Computer Center Kunming University of Science and Technology

Essential proteins are vital to the survival of a cell. There are various features related to the essentiality of proteins, such as biological and topological features. Many computational methods have been developed to identify essential proteins by using these features. However, it is still a big challenge to design an effective method that is able to select suitable features and integrate them to predict essential proteins. In this work, we first collect 26 features, and use SVM-RFE to select some of them to create a feature space for predicting essential proteins, and then remove the features that share the biological meaning with other features in the feature space according to their Pearson Correlation Coefficients（PCC）. The experiments are carried out on S. cerevisiae data. Six features are determined as the best subset of features. To assess the prediction performance of our method, we further compare it with some machine learning methods, such as SVM, Naive Bayes, Bayes Network, and NBTree when inputting the different number of features. The results show that those methods using the 6 features outperform that using other features, which confirms the effectiveness of our feature selection method for essential protein prediction.

关键词： essential protein feature selection Protein-Protein Interaction(PPI) machine learning centrality algorithm

Kernelization in Parameterized Computation: A Survey

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Tsinghua Science and Technology 2014年第4期19卷 338-345页

作者： Qilong Feng Qian Zhou Wenjun Li jianxin wang the School of Information Science and Engineering Central South University

Parameterized computation is a new method dealing with NP-hard problems, which has attracted a lot of attentions in theoretical computer science. As a practical preprocessing method for NP-hard problems, kernelizaiton in parameterized computation has recently become an active research area. In this paper, we discuss several kernelizaiton techniques, such as crown decomposition, planar graph vertex partition, randomized methods, and kernel lower bounds, which have been used widely in the kernelization of many hard problems.

关键词： parameterized computation kernelization parameterized algorithm NP-hard

Diode Laser Soldering Technology of Fine Pitch QFP Devices

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 917-922页

作者： XUE Songbai ZHANG Liang HAN Zongjie wang jianxin YU Shenglin College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China School of Mechanical and Electrical Engineering Xuzhou Normal University Xuzhou 221116 China The 14th Research Institute China Electronics Technology Group Corporation Nanjing 210013 China

The laser provides a controllable means of supplying localized energy for solder joint formation and is a valuable tool in electronics *** laser soldering for fine pitch QFP devices were carried out with Sn-Ag-Cu lead-free solder and Sn-Pb solder respectively,and the mechanical properties of micro-joints of the QFP devices were tested and studied by STR-1000 micro-joints *** results indicate that sound QFP micro-joints without bridging or solder ball are gained by means of diode laser soldering method with appropriate laser processing parameters,and the pitch of the QFP devices is as fine as to *** strength of QFP micro-joints increases gradually with the increase of laser output power,the maximum tensile strength presents when the laser output power increase to a certain *** results also indicate that the mechanical properties of QFP micro-joints soldered by diode laser soldering system are better than those of QFP micro-joints soldered by IR reflow soldering *** experimental results may provide a theory guide for investigation of diode laser soldering.

关键词： diode laser soldering QFP device mechanical properties of micro-joint

Computational Approaches for Prioritizing Candidate Disease Genes Based on PPI Networks

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Tsinghua Science and Technology 2015年第5期20卷 500-512页

作者： Wei Lan jianxin wang Min Li Wei Peng Fangxiang Wu the School of Information Science and Engineering Central South University the Department of Mechanical Engineering and Division of Biomedical Engineering University of Saskatchewan

With the continuing development and improvement of genome-wide techniques, a great number of candidate genes are discovered. How to identify the most likely disease genes among a large number of candidates becomes a fundamental challenge in human health. A common view is that genes related to a specific or similar disease tend to reside in the same neighbourhood of biomolecular networks. Recently, based on such observations,many methods have been developed to tackle this challenge. In this review, we firstly introduce the concept of disease genes, their properties, and available data for identifying them. Then we review the recent computational approaches for prioritizing candidate disease genes based on Protein-Protein Interaction（PPI） networks and investigate their advantages and disadvantages. Furthermore, some pieces of existing software and network resources are summarized. Finally, we discuss key issues in prioritizing candidate disease genes and point out some future research directions.

关键词： candidate disease-gene prioritization protein-protein interaction network human disease computational tools