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Effective Query Grouping Strategy in Clouds

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Journal of Computer Science & Technology 2017年第6期32卷 1231-1249页

作者： Qin Liu Yuhong guo Jie Wu guojun Wang College of Computer Science and Electronic Engineering Hunan University Changsha 410082 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Computer Science Carleton University Ottawa ON K155B6 Ganada Department of Computer and Information Sciences Temple University Philadelphia PA 19122 U.S.A. School of Computer Science and Educational Software Guangzhou University Guangzhou 510006 China

As the demand for the development of cloud computing grows, more and more organizations have outsourced their data and query services to the cloud for cost-saving and flexibility. Suppose an organization that has a great number of users querying the cloud-deployed multiple proxy servers to achieve cost efficiency and load balancing. Given n queries, each of which is expressed as several keywords, and k proxy servers, the problem to be solved is how to classify n queries into k groups, in order to minimize the difference between each group and the number of distinct keywords in all groups. Since this problem is NP-hard, it is solved in mathematic and heuristic ways. Mathematic grouping uses a local optimization method, and heuristic grouping is based on k-means. Specifically, two extensions are provided： the first one focuses on robustness, i.e., each user obtains search results even if some proxy servers fail; the second one focuses on benefit, i.e., each user can retrieve as many files as possible that may be of interest without increasing the sum. Extensive evaluations have been conducted on both a synthetic dataset and real query traces to verify the effectiveness of our strategies.

关键词： cloud computing cost efficiency load balancing robustness benefit

Adsorption of mercury on laterite from Guizhou Province,China

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Journal of Environmental Sciences 2008年第11期20卷 1328-1334页

作者： YU Xiaohong ZHU Lijun guo Baiwei HE Shouyang The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Karst Environment and Geohazard Prevention Ministry of Education Guiyang 550003 China College of Civil Engineering and Building Construction of Guizhou University Guiyang 550003 China

The adsorption behaviors of Hg(Ⅱ) on laterite from Guizhou Province,China,were studied and the adsorption mechanism was *** results showed that different mineral compositons in the laterite will cause differences in the adsorption capacity of laterite to Hg(Ⅱ).Illite and non-crystalloids are the main contributors to enhancing the adsorption capacity of laterite to Hg(Ⅱ).The pH of the solution is an important factor affecting the adsorption of Hg(Ⅱ) on *** alkalescent environment (pH 7-9) ...

关键词： adsorption laterite Hg(Ⅱ) pH isotherm kinetics

A closed-form nonlinear model for spatial Timoshenko beam flexure hinge with circular cross-section

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Chinese Journal of Aeronautics 2019年第11期32卷 2526-2537页

作者： Dan WANG Jie ZHANG Jiangzhen guo Rui FAN School of Mechanical Engineering and Automation Beihang University

Beam flexure hinges can achieve accurate motion and force control through the elastic deformation. This paper presents a nonlinear model for uniform and circular cross-section spatial beam flexure hinges which are commonly employed in compliant parallel mechanisms. The proposed beam model takes shear deformations into consideration and hence is applicable to both slender and thick beam flexure hinges. Starting from the first principles, the nonlinear strain measure is derived using beam kinematics and expressed in terms of translational displacements and rotational angles. Second-order approximation is employed in order to make the nonlinear strain within acceptable accuracy. The natural boundary conditions and nonlinear governing equations are derived in terms of rotational Euler angles and subsequently solved for combined end loads. The resulting end load-displacement model, which is compact and closed-form, is proved to be accurate for both slender and thick beam flexure using nonlinear finite element analysis. This beam model can provide designers with more design insight of the spatial beam flexure and thus will benefit the structural design and optimization of compliant manipulators.

关键词： Compliant mechanism Load-displacement model Nonlinear analysis Spatial beam flexure hinge(SBFH) Timoshenko beam

Restoring force correction based on online discrete tangent stiffness estimation method for real-time hybrid simulation

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 805-820页

作者： Huang Liang guo Tong Chen Cheng Chen Menghui School of Civil Engineering Southeast University Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education Southeast University School of Engineering San Francisco State University

In real-time hybrid simulation（RTHS）, it is difficult if not impossible to completely erase the error in restoring force due to actuator response delay using existing displacement-based compensation methods. This paper proposes a new force correction method based on online discrete tangent stiffness estimation（online DTSE） to provide accurate online estimation of the instantaneous stiffness of the physical substructure. Following the discrete curve parameter recognition theory, the online DTSE method estimates the instantaneous stiffness mainly through adaptively building a fuzzy segment with the latest measurements, constructing several strict bounding lines of the segment and calculating the slope of the strict bounding lines, which significantly improves the calculation efficiency and accuracy for the instantaneous stiffness estimation. The results of both computational simulation and real-time hybrid simulation show that：（1） the online DTSE method has high calculation efficiency, of which the relatively short computation time will not interrupt RTHS; and（2） the online DTSE method provides better estimation for the instantaneous stiffness, compared with other existing estimation methods. Due to the quick and accurate estimation of instantaneous stiffness, the online DTSE method therefore provides a promising technique to correct restoring forces in RTHS.

关键词： online discrete tangent stiffness estimation restoring force correction fuzzy segment parameter updating real-time hybrid simulation

Liquid-holdup regions research of novel reactive distillation column for C5 fraction separation

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Chinese Journal of Chemical Engineering 2017年第4期25卷 433-441页

作者： Liang guo Tiefeng Wang Dongfeng Li Jinfu Wang Beijing Key Laboratory of Green Reaction Engineering and Technology Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Beijing Research Institute of Chemical Industry Beijing 100013China

Recent advances in technologies of reactive distillation(RD) offer various design concepts for chemical *** separation of cracking C5 fraction, one of the main challenges is improving the conversion of cyclopentadiene(CPD) and the recovery of isoprene(IP). In the current work, a novel reactive distillation column with several liquid-holdup regions was designed, since it allows long residence time and provides flexibility for narrowing the efficiency gap between reaction and distillation. By use of Aspen Plus, a corresponding mathematic model was established and verified to be accurate. Following that, comprehensive studies were carried out for the design of liquid-holdup regions position. Details and principles about the separation performance with the liquid-holdup regions were revealed and optimized parameters were determined with 100 theoretical plates,feed position of 35 th plate, and four liquid-holdup regions at 25 th, 60 th, 75 th and 90 th plate. The designed RD column could well meet the technical requirement, and influence of other important factors including residence time, operating pressure and reflux ratio was further investigated.

关键词： distillation residence Aspen verified cracking requirement challenges selectivity hence enthalpy

Selective separation of silica from a siliceous-calcareous phosphate rock

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Mining Science and Technology 2011年第1期21卷 135-139页

作者： guo Fang Li Jun College of Chemical Engineering Sichuan University Chengdu 610065. China

Selective separation of silica from a siliceous-calcareous phosphate ore that had been sieved into different size fractions is investigated by a combination of chemical analysis,zeta potential measurement and FTIR and XPS *** is a better choice than flotation for removing silica from the coarse *** P_2O_5 grade of the coarse fractions is increased to about 30%by scrubbing and the product yields are higher than those obtained by *** silica in the fine fraction is separated by reverse *** alkyl amine salt(DAH)is an effective collector and the P_2O_5 grade of the fine fraction can be increased by 7%to beyond 30%under acidic *** higher zeta potential obtained using DAH suggests that it is more strongly absorbed onto the ore particles than the other cationic collectors. FTIR and XPS results confirm physical absorption of the cationic collector onto the ore *** also indicate that calcite is dissolved at low pH values,which increases the Si concentration on the ore surface.

关键词： Siliceous-calcareous phosphate rock Silica separation Reverse flotation Calcite gangue

Spatial distribution and pollution assessment of heavy metals in urban soils from southwest China

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Journal of Environmental Sciences 2012年第3期24卷 410-418页

作者： Guanghui guo Fengchang Wu Fazhi Xie Ruiqing Zhang Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China Graduate university of the Chinese Academy of Science Beijing 100049China State Key Laboratory of Environmental Criteria and RiskAssessment Chinese Research Academy of Environment SciencesBeijing 100012China CAS Key Laboratory of Crust-Mantle Materials and Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

To identify the concentrations and sources of heavy metals, and to assess soil environmental quality, 63 soil samples were collected in Yibin City, Sichuan Province, China. Mean concentrations of As, Pb, Zn, and Cu were 10.55, 61.23, 138.88 and 56.35 mg/kg, respectively. As concentrations were comparable to background values, while Pb, Zn, and Cu concentrations were higher than their corresponding background values. Industrial areas exhibited the highest concentrations of As, Pb, Zn, and Cu, while the lowest concentrations occurred in parks. Statistical analysis was performed and two cluster groups of metals were identified with Pb, Zn, and Cu in one group and As in the other. Spatial distribution maps indicated that Pb, Zn, and Cu were mainly controlled by anthropogenic activities, whereas As could be mainly accounted for by soil parent materials. Pollution index values of As, Pb, Zn, and Cu varied in the range of 0.24-1.93, 0.66-7.24, 0.42-4.19, and 0.62-5.25, with mean values of 0.86, 1.98, 1.61, and 1.78, respectively. The integrated pollution index （IPI） values of these metals varied from 0.82 to 3.54, with a mean of 1.6 and more than 90% of soil samples were moderately or highly contaminated with heavy metals. The spatial distribution of IPI showed that newer urban areas displayed relatively lower heavy metal contamination in comparison with older urban areas.

关键词： urban soils heavy metals pollution assessment spatial distribution

A Novel Approach to Improve the Detectability of CO_2 by GC Analysis

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Chinese Chemical Letters 2003年第2期14卷 181-184页

作者： Wei Min guo Yu An SUN 等 DepartmentofChemistry UniversityofScienceandTechnologyofChinaHefei230026 DepartmentofChemicalEngineering ZhengzhouInstituteofLightIndustryZhengzhou450002

A novel stochastic resonance algorithm was employed to enhance the signal-to-noise ratio (SNR) of signals of analytical chemistry. By using a gas chromatographic data set, it was proven that the SNR was greatly improved and the quantitative relationship between concentrations and chromatographic responses remained simultaneously. The linear range was extended beyond the instrumental detection limit.

关键词： Stochastic resonance detectability gas chromatography.

A probabilistic framework of preference discovery from folksonomy corpus

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Frontiers of Computer Science 2017年第6期11卷 1075-1084页

作者： Xiaohui guo Chunming HU Richong ZHANG Jinpeng HUAI State Key Lab of Software Development Environment Beihang University Beijing 100191 China Institute of Advanced Computing Technology School of Computer Science and Engineering Beihang University Beijing 100191 China

The increasing availability of folksonomy data makes them vital for user profiling approaches to precisely detect user preferences and better understand user interests, so as to render some personalized recommendation or re- trieval results. This paper presents a rigorous probabilis- tic framework to discover user preference from folkson- omy data. Furthermore, we incorporate three models into the framework with the corresponding inference methods, expectation-maximization or Gibbs sampling algorithms. The user preference is expressed through topical conditional distributions. Moreover, to demonstrate the versatility of our framework, a recommendation method is introduced to show the possible usage of our framework and evaluate the applica- bility of the engaged models. The experimental results show that, with the help of the proposed framework, the user pref- erence can be effectively discovered.

关键词： preference discovery tagging folksonomy so-cial annotation