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The deep and low-mass-ratio contact binary CSS J022914.4+044340 with a luminous additional companion

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Research in Astronomy and Astrophysics 2021年第7期21卷 254-260页

作者： liang liu xu-zhi li Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

The first B-,V-,R_c-and I_c-band light curves of CSS J022914.4+044340 are presented and *** is found that CSS J022914.4+044340 is a low mass ratio(0.198 ± 0.005) deep(63.7 ± 7.9 %)contact binary,indicating that it is already at the end evolutionary stage of tidally-locked evolution via magnetized *** of the totally eclipsing character,the photometric solutions are *** temperature and metallicity are determined from the spectroscopic data as T=5855 ± 15 K and[Fe/H]=-0.842 ± 0.031,*** on the parallax of Gaia EDR3,the physical parameters of CSS J022914.4+044340 are estimated as M_(1)=1.44_(-0.22)^(+0.25) M_⊙,M_(2)=0.29_(-0.05)^(0.05) M_⊙,R_(1)=1.26_(-0.06)^(0.08) R_⊙,R2=0.65_(-0.04)^(0.03) R_⊙,L_(1)=1.718_(0.191)^(0.186) L_⊙ and L_(2)=0.416_(-0.050)^(0.039) L_⊙.Combining the fraction of light from the third body via the photometric solution(54%),the luminosity of the third body is estimated as 2.705 L_⊙.The third body may be inferred to be a ***,why the primary component of CSS J022914.4+044340 has higher mass compared to similar systems is explained,as well as why its metallicity is so poor.

关键词： binaries:eclipsing binaries:close stars:individuals(CSS J022914.4+044340) stars:evolution

Discovering Functional Organized Keyword Recommendation Point of Interest Groups for Spatial

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Journal of Computer Science & Technology 2018年第4期33卷 697-710页

作者： Yan-Xia xu Wei Chen Jia-Jie xu zhi-xu li Guan-Feng liu Lei Zhao School of Computer Science and Technology Soochow University Suzhou 215006 China

A point of interest （POI） is a specific point location that someone may find useful. With the development of urban modernization, a large number of functional organized POI groups （FOPGs）, such as shopping malls, electronic malls, and snacks streets, are springing up in the city. They have a great influence on people＇s lives. We aim to discover functional organized POI groups for spatial keyword recommendation because FOPGs-based recommendation is superior to POIs-based recommendation in efficiency and flexibility. To discover FOPGs, we design clustering algorithms to obtain organized POI groups （OPGs） and utilize OPGs-LDA （Latent Dirichlet Allocation） model to reveal functions of OPGs for further recommendation. To the best of our knowledge, we are the first to study functional organized POI groups which have important applications in urban planning and social marketing.

关键词： functional organized point of interest (POI) group POI clustering OPG-LDA (organized point of interest group-latent Dirichlet allocation) model spatial keyword recommendation

Scalable and Adaptive Joins for Tra jectory Data in Distributed Stream System

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Journal of Computer Science & Technology 2019年第4期34卷 747-761页

作者： Jun-Hua Fang Peng-Peng Zhao An liu zhi-xu li Lei Zhao Institute of Artificial Intelligence School of Computer Science and TechnologySoochow UniversitySuzhou 215006ChinaNeusoft CorporationShenyang 110179China Institute of Artificial Intelligence School of Computer Science and TechnologySoochow UniversitySuzhou 215006China

As a fundamental operation in LBS(location-based services),the trajectory similarity of moving objects has been extensively studied in recent ***,due to the increasing volume of moving object trajectories and the demand of interactive query performance,the trajectory similarity queries are now required to be processed on massive datasets in a real-time *** work has proposed distributed or parallel solutions to enable large-scale trajectory similarity ***,those techniques cannot be directly adapted to the real-time scenario as it is likely to generate poor balancing performance when workload variance occurs on the incoming trajectory *** this paper,we propose a new workload partitioning framework,ART(Adaptive Framework for Real-Time Trajectory Similarity),which introduces practical algorithms to support dynamic workload assignment for RTTS(real-time trajectory similarity).Our proposal includes a processing model tailored for the RTTS scenario,a load balancing framework to maximize throughput,and an adaptive data partition manner designed to cut off unnecessary network *** on this,our model can handle the large-scale trajectory similarity in an on-line scenario,which achieves scalability,effectiveness,and efficiency by a single *** studies on synthetic data and real-world stream applications validate the usefulness of our proposal and prove the huge advantage of our approach over state-of-the-art solutions in the literature.

关键词： real-time data processing distributed computing trajectory similarity load balancing

An Efficient Framework for Multiple Subgraph Pattern Matching Models

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Journal of Computer Science & Technology 2019年第6期34卷 1185-1202页

作者： Jiu-Ru Gao Wei Chen Jia-Jie xu An liu zhi-xu li Hongzhi Yin Lei Zhao School of Computer Science and Technology Soochow UniversitySuzhou 215006China School of Information Technology and Electrical Engineering The University of QueenslandBrisbane 4072Australia

With the popularity of storing large data graph in cloud, the emergence of subgraph pattern matching on a remote cloud has been inspired. Typically, subgraph pattern matching is defined in terms of subgraph isomorphism, which is an NP-complete problem and sometimes too strict to find useful matches in certain applications. And how to protect the privacy of data graphs in subgraph pattern matching without undermining matching results is an important concern. Thus, we propose a novel framework to achieve the privacy-preserving subgraph pattern matching in cloud. In order to protect the structural privacy in data graphs, we firstly develop a k-automorphism model based method. Additionally, we use a cost-model based label generalization method to protect label privacy in both data graphs and pattern graphs. During the generation of the k-automorphic graph, a large number of noise edges or vertices might be introduced to the original data graph. Thus, we use the outsourced graph, which is only a subset of a k-automorphic graph, to answer the subgraph pattern matching. The efficiency of the pattern matching process can be greatly improved in this way. Extensive experiments on real-world datasets demonstrate the high efficiency of our framework.

关键词： subgraph pattern matching k-automorphism label generalization

Privacy-Preserving Task Assignment in Spatial Crowdsourcing

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Journal of Computer Science & Technology 2017年第5期32卷 905-918页

作者： An liu zhi-xu li Guan-Feng liu Kai Zheng Min Zhang Qing li Xiangliang Zhang School of Computer Science and Technology Soochow University Suzhou 215006 China School of Computer Science and Technology Soochow University Suzhou 215006 China Beijing Key Laboratory of Big Data Management and Analysis Methods Beijing 100872 China Department of Computer Science City University of Hong Kong Hong Kong China King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia

With the progress of mobile devices and wireless networks, spatial crowdsourcing （SC） is emerging as a promising approach for problem solving. In SC, spatial tasks are assigned to and performed by a set of human workers. To enable effective task assignment, however, both workers and task requesters are required to disclose their locations to untrusted SC systems. In this paper, we study the problem of assigning workers to tasks in a way that location privacy for both workers and task requesters is preserved. We first combine the Paillier cryptosystem with Yao＆#39;s garbled circuits to construct a secure protocol that assigns the nearest worker to a task. Considering that this protocol cannot scale to a large number of workers, we then make use of Geohash, a hierarchical spatial index to design a more efficient protocol that can securely find approximate nearest workers. We theoretically show that these two protocols are secure against semi-honest adversaries. Through extensive experiments on two real-world datasets, we demonstrate the efficiency and effectiveness of our protocols.

关键词： spatial crowdsourcing spatial task assignment location privacy mutual privacy protection

Solvability conditions for algebra inverse eigenvalue problem over set of anti-Hermitian generalized anti-Hamiltonian matrices

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Journal of Central South University of Technology 2005年第Z1期12卷 294-297页

作者： ZHANG Zhong-zhi HAN xu-li School of Mathematics and Computational Science Central South University Changsha 410083 China Department of Mathematics Dongguan University of Technology Dongguan 523000 China School of Mathematics and Computational Science Central South University Changsha 410083 China

By using the characteristic properties of the anti-Hermitian generalized anti-Hamiltonian matrices, we prove some necessary and sufficient conditions of the solvability for algebra inverse eigenvalue problem of anti-Hermitian generalized anti-Hamiltonian matrices, and obtain a general expression of the solution to this problem. By using the properties of the orthogonal projection matrix, we also obtain the expression of the solution to optimal approximate problem of an n× n complex matrix under spectral restriction.

关键词： anti-Hermitian generalized anti-Hamiltonian matrix algebra inverse eigenvalue problem optimal approximation

Supporting multi-user real-time VBR video service using dynamic bandwidth management based on prediction

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The Journal of China Universities of Posts and Telecommunications 2009年第6期16卷 64-71页

作者： xu zhi-yuan li Hui LU Yue-ming JI Yue-feng Key Laboratory of Optical Communications and lightwave Technologies Beijing University of Posts and Telecommunications Beijing 100876 China

Real-time variable bit rate（VBR） video is expected to take a significant portion of multimedia ***,plentiful challenges to VBR video service provision have been raised for its characteristic of high traffic *** support multi-user real-time VBR video transmission with high bandwidth utilization and satisfied quality of service（QoS）,this article proposes a practical dynamic bandwidth management *** scheme forecasts future media rate of VBR video by employing time-domain adaptive linear predictor and using media delivery index（MDI） as both QoS measurement and complementary management *** addition,to support multi-user application,an adjustment priorities classified strategy is also put ***,a test-bed based on this management scheme is *** experimental results demonstrate that the scheme proposed in this article is efficient with bandwidth utilization increased by 20%-60% compared to a fixed service rate and QoS guaranteed.

关键词： dynamic bandwidth management MDI QoS real-time time-domain adaptive linear predictor VBR video

Crowd-Guided Entity Matching with Consolidated Textual Data

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Journal of Computer Science & Technology 2017年第5期32卷 858-876页

作者： zhi-xu li Qiang Yang An liu Guan-Feng liu Jia Zhu Jia-Jie xu Kai Zheng Min Zhang School of Computer Science and Technology Soochow University Suzhou 215006 China Guangdong Key Laboratory of Big Data Analysis and Processing Guangzhou 510006 China School of Computer Science and Technology Soochow University Suzhou 215006 China School of Computer South China Normal University Guangzhou 510631 China School of Computer Science and Technology Soochow University Suzhou 215006 China Beijing Key Laboratory of Big Data Management and Analysis Methods Beijing 100872 China

Entity matching (EM) identifies records referring to the same entity within or across databases. Existing methods using structured attribute values (such as digital, date or short string values) may fail when the structured information is not enough to reflect the matching relationships between records. Nowadays more and more databases may have some unstructured textual attribute containing extra consolidated textual information (CText) of the record, but seldom work has been done on using the CText for EM. Conventional string similarity metrics such as edit distance or bag-of-words are unsuitable for measuring the similarities between CText since there are hundreds or thousands of words with each piece of CText, while existing topic models either cannot work well since there are no obvious gaps between topics in CText. In this paper, we propose a novel cooccurrence-based topic model to identify various sub-topics from each piece of CText, and then measure the similarity between CText on the multiple sub-topic dimensions. To avoid ignoring some hidden important sub-topics, we let the crowd help us decide weights of different sub-topics in doing EM. Our empirical study on two real-world datasets based on Amzon Mechanical Turk Crowdsourcing Platform shows that our method outperforms the state-of-the-art EM methods and Text Understanding models.

关键词： entity matching consolidated textual data crowdsourcing

Layered niobium carbide enabling excellent kinetics and cycling stability of li-Mg-B-H hydrogen storage material Layered niobium carbide enabling excellent kinetics

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Rare Metals 2024年第3期43卷 1153-1166页

作者： li-Wen Lu Hui Luo Guang-xu li Yun li Xin-Hua Wang Cun-Ke Huang zhi-QiangLan Wen-Zheng Zhou Jin Guo Mohammad Ismail Hai-Zhen liu Guangxi Novel Battery Materials Research Center of Engineering Technology Guangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China State Key Laboratory of Featured Metal Materials and life-Cycle Safety for Composite Structures Nanning530004China School of Mechanical and Electrical Engineering Quzhou College of TechnologyQuzhou324000China Department of Materials Science and Engineering Zhejiang UniversityHangzhou310027China Faculty of Ocean Engineering Technology and Informatics Universiti Malaysia Terengganu21030Kuala NerusTerengganuMalaysia Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin300071China

The li-Mg-B-H composite(2liBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage ***,the slow kinetics and poor cycling stability severely restrict its practical *** this work,a layered Nb_(2)C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the li-Mg-B-H *** milled 2liH+MgB_(2)composites were initially hydrogenated to obtain the 2liBH_(4)+MgH_(2)*** 2liBH_(4)+MgH_(2)+5wt%Nb_(2)C can release 9.0 wt%H_(2)in 30 min at 400℃,while it is only 2.7 wt%for the undoped 2liBH_(4)+MgH_(2).The dehydrogenation activation energies of MgH_(2)and liBH_(4)are 123 and 154 kJ·mol^(-1)respectively for the 5 wt%Nb_(2)C-doped composite,lower than the undoped composite(164 and 165 kJ·mol^(-1)).The 2liBH_(4)+MgH_(2)+5 wt%Nb_(2)C possesses excellent cycling stability,with the reversible capacity only slightly reduced from 9.4 wt%for the 1st cycle to 9.3 wt%for the 20th ***_(2)C keeps stable in the composite and acts as an efficient catalyst for the li-Mg-B-H *** is believed that both the layered structure and the active Nb element contribu te to the enhanced hydrogen storage performances of the li-Mg-B-H *** work confirms that the Nb_(2)C MXene with layered stru cture has a significant enhancing impact on the li-Mg-B-H hydrogen storage materials,which is different from the bulk NbC.

关键词： Hydrogen storage lithium borohydride Magnesium hydride Nb_(2)C MXene