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Search Result Diversification Based on Query Facets

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Journal of Computer Science & Technology 2015年第4期30卷 888-901页

作者：胡莎窦志成王晓捷文继荣 School of Information Renmin University of China Beijing 100872 China Key Laboratory of Data Engineering and Knowledge Engineering Ministry of Education Beijing 100872 China

In search engines, different users may search for different information by issuing the same query. To satisfy more users with limited search results, search result diversification re-ranks the results to cover as many user intents as possible. Most existing intent-aware diversification algorithms recognize user intents as subtopics, each of which is usually a word, a phrase, or a piece of description. In this paper, we leverage query facets to understand user intents in diversification, where each facet contains a group of words or phrases that explain an underlying intent of a query. We generate subtopics based on query facets and propose faceted diversification approaches. Experimental results on the public TREC 2009 dataset show that our faceted approaches outperform state-of-the-art diversification models.

关键词： query intent query facet search result diversification

Analysis of key microbial community during the start-up of anaerobic ammonium oxidation process with paddy soil as inoculated sludge

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Journal of Environmental Sciences 2018年第2期30卷 317-327页

作者： Xianglong Xu Guohua Liu Yuanyuan Wang Yuankai Zhang Hao Wan Lu Qi Hongchen Wang School of Environment & Natural Resources Renmin University of China

A sequencing batch reactor（SBR）-anaerobic ammonium oxidation（anammox） system was started up with the paddy soil as inoculated sludge. The key microbial community structure in the system along with the enrichment time was investigated by using molecular biology methods（e.g., high-throughput 16 S r RNA gene sequencing and quantitative PCR）. Meanwhile,the influent and effluent water quality was continuously monitored during the whole start-up stage. The results showed that the microbial diversity decreased as the operation time initially and increased afterwards, and the microbial niches in the system were redistributed. The anammox bacterial community structure in the SBR-anammox system shifted during the enrichment, the most dominant anammox bacteria were Candidatus Jettenia. The maximum biomass of anammox bacteria achieved 1.68 × 10~9 copies/g dry sludge during the enrichment period, and the highest removal rate of TN achieved around 75%.

关键词： Anammox Paddy soil Community structure High-throughput sequencing qPCR

Iron-catalyzed aerobic oxidative amidation of tertiary amines with carboxylic acids

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Science china Chemistry 2015年第8期58卷 1310-1315页

作者： Lina Ma Yuanming Li Zhiping Li Department of Chemistry Renmin University of China

An oxidative amidation of tertiary amines with carboxylic acids has been developed in the presence of FeC13- 6H20 as catalyst and oxygen as oxidant. A variety of tertiary amides were obtained in good to excellent yiel... 详细信息

关键词： amidation tertiary amine carboxylic acid iron catalysis oxidation

MiNT-OLAP cluster： minimizing network transmission cost in OLAP cluster for main memory analytical database

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Frontiers of Computer Science 2012年第6期6卷 668-676页

作者： Min JIAO Yansong ZHANG Zhanwei WANG Shan WANG DEKE Lab Renmin University of ChinaBeijing 100872China National Survey research Center Renmin University of ChinaBeijing 100872China School of Information Renmin University of ChinaBeijing 100872China

Powerful storage, high performance and scalability are the most important issues for analytical databases. These three factors interact with each other, for example, powerful storage needs less scalability but higher performance, high performance means less consumption of indexes and other materializations for storage and fewer processing nodes, larger scale relieves stress on powerful storage and the high performance processing engine. Some analytical databases （ParAccel, Teradata） bind their performance with advanced hardware supports, some （Asterdata, Greenplum） rely on the high scalability framework of MapReduce, some （MonetDB, Sybase IQ, Vertica） highlight performance on processing engine and storage engine. All these approaches can be integrated into an storage-performance-scalability （S- P-S） model, and future large scale analytical processing can be built on moderate clusters to minimize expensive hardware dependency. The most important thing is a simple software framework is fundamental to maintain pace with the development of hardware technologies. In this paper, we propose a schemaaware on-line analytical processing （OLAP） model with deep optimization from native features of the star or snowflake schema. The OLAP model divides the whole process into several stages, each stage pipes its output to the next stage, we minimize the size of output data in each stage, whether in central processing or clustered processing. We extend this mechanism to cluster processing using two major techniques, one is using NetMemory as a broadcasting protocol based dimension mirror synchronizing buffer, the other is predicatevector based DDTA-OLAP cluster model which can minimize the data dependency of star-join using bitmap vectors. Our OLAP model aims to minimize network transmission cost （MINT in short） for OLAP clusters and support a scalable but simple distributed storage model for large scale clustering processing. Finally, the experimental results show the speedup and s

关键词： OLAP cluster MINT NetMemory schemaaware OLAP

Self-healing Ionic Liquid-based Electronics and Beyond

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Chinese Journal of Polymer Science 2021年第10期39卷 1235-1245,I0005页

作者： Shenglong Liao Xiaodong Lian Yapei Wang Department of Chemistry Renmin University of ChinaBeijing 100872China

Owing to the advantages of non-volatility,outstanding fluidity and easy recyclability,ionic liquid-based electronics,such as thermometer,strain sensors and thermoelectric converters,have been growing as attractive alternatives to traditionally solid *** fluidic character endows the ionic liquid-based circuit with self-healing ability,satisfying the needs of longer lifetime and less waste generation for electronics,while at the same time brings the risk of *** the leakage without sacrifice of self-healing ability is one of the major challenges for constructing ionic liquid-based electronic *** this feature article,we summarize our recent progresses in developing two types of self-healing electrical devices based on ionic liquids with little risk of *** type involves the encapsulation of ionic liquids in self-healing polymers,and the other type uses ionic polymers or free-standing ionic liquids which are successfully formulated as intrinsically conductive,self-healing,and recyclable electronic devices without additional *** the end,a comprehensive outlook is prospected for the future development of ionic liquid-based self-healing electronics,which is expected to spur more innovative work in this field.

关键词： Self-healing electronics Self-healing materials Recyclable electronics Ionic liquid Liquid leakage

Local Polynomial-Brunk Estimation in Semi-Parametric Monotone Errors-in-Variables Model with Right-Censored Data

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Journal of Systems Science & Complexity 2015年第4期28卷 938-960页

作者： XIA Wei CHEN Zhao WU Wuqing ZHOU Jianjun Department of Finance and Statistics University of Science and TechnologyHefei Department of Operations research and Financial Engineering Princeton University School of Business Renmin University of China School of Mathematics and Statistics Yunnan University

This paper introduces a semi-parametric model with right-censored data and a monotone constraint on the nonparametrie part. The authors study the local linear estimators of the parametric coefficients and apply B-spline method to approximate the nonparametric part based on grouped data. The authors obtain the rates of convergence for parametric and nonparametric estimators. Moreover, the authors also prove that the nonparametric estimator is consistent at the boundary. At last, the authors investigate the finite sample performance of the estimation.

关键词： B-spline grouped brunk local polynomial monotone regression right-censored semi-parametric model.

Rapid degradation of dyes in water by magnetic Fe^0/Fe_3O_4/graphene composites

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Journal of Environmental Sciences 2016年第6期28卷 148-157页

作者： Shan Chong Guangming Zhang Huifang Tian He Zhao School of Environment & Natural Resource Renmin University of China

Magnetic Fe^0/Fe3O4/graphene has been successfully synthesized by a one-step reduction method and investigated in rapid degradation of dyes in this work. The material was characterized by N2 sorption–desorption, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, vibrating-sample magnetometer（VSM） measurements and X-ray photoelectron spectroscopy（XPS）. The results indicated that Fe^0/Fe3O4/graphene had a layered structure with Fe crystals highly dispersed in the interlayers of graphene, which could enhance the mass transfer process between Fe^0/Fe3O4/graphene and pollutants. Fe^0/Fe3O4/graphene exhibited ferromagnetism and could be easily separated and re-dispersed for reuse in water. Typical dyes, such as Methyl Orange, Methylene Blue and Crystal Violet, could be decolorized by Fe^0/Fe3O4/graphene rapidly. After 20 min, the decolorization efficiencies of methyl orange, methylene blue and crystal violet were 94.78%, 91.60% and 89.07%, respectively. The reaction mechanism of Fe^0/Fe3O4/graphene with dyes mainly included adsorption and enhanced reduction by the composite. Thus, Fe^0/Fe3O4/graphene prepared by the one-step reduction method has excellent performance in removal of dyes in water.

关键词： Fe^0/Fe3O4/graphene Magnetic Dyes Removal Reduction

Distance-dependent magnetization modulation induced by inter-superatomic interactions in Cr-doped Au₆Te₁₂Se₈ dimers

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CHINESE PHYSICS B 2024年第12期33卷 127502-127502页

作者： Guan, Yurou Liu, Nanshu Wang, Cong Pang, Fei Cheng, Zhihai Ji, Wei renmin Univ china Sch Phys Beijing Key Lab Optoelect Funct Mat & Micronano De Beijing 100872 Peoples R China renmin Univ china Key Lab Quantum State Construct & Manipulat Minist Educ Beijing 100872 Peoples R China

Individual superatoms are assembled into more complicated nanostructures to diversify their physical properties. Magnetism of assembled superatoms remains, however, ambiguous, particularly in terms of its distance dependence. Here, we report density functional theory calculations on the distance-dependent magnetism of transition metal embedded Au6Te8Se12 (ATS) superatomic dimers. Among the four considered transition metals, which include V, Cr, Mn and Fe, the Cr-embedded Au6Te12Se8 (Cr@ATS) is identified as the most suitable for exploring the inter-superatomic distance-dependent magnetism. We thus focused on Cr@ATS superatomic dimers and found an inter-superatomic magnetization-distance oscillation where three transitions occur for magnetic ordering and/or anisotropy at different inter-superatomic distances. As the inter-superatomic distance elongates, a ferromagnetism (FM)-to-antiferromagnetic (AFM) transition and a sequential AFM-to-FM transition occur, ascribed to competitions among Pauli repulsion and kinetic-energy-gains in formed inter-superatomic Cr-Au-Au-Cr covalent bonds and Te-Te quasi-covalent bonds. For the third transition, in-plane electronic hybridization contributes to the stabilization of the AFM configuration. This work unveils two mechanisms for tuning magnetism through non-covalent interactions and provides a strategy for manipulating magnetism in superatomic assemblies.

关键词： low dimensional materials magnetic interactions

Nonlinear dynamics of pork price in china

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Journal of Integrative Agriculture 2015年第6期14卷 1115-1121页

作者： ZHAO Guo-qing WU Qiong School of Economics Renmin University of China

This paper primarily analyzes the evolution path of china＇s pork price by employing the threshold autoregression model（TAR）. Considering the unit root test with a threshold effect and heteroskedasticity of the TAR model, we show that the pork price series is a unit root process in each regime, and the heteroskedasticity in the TAR model greatly affects the results of linearity test. We find that the changing process of pork price has two regimes： mild regime and expansion regime. In particular, a change belongs to an expansion regime if it is larger than 0.5881; otherwise, it falls in the mild regime.

关键词： bootstrap regime volatility autoregressive otherwise belongs expenditure prices household EGARCH