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A Flexible Space-Time Tradeoff on Hybrid Index with Bicriteria Optimization

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Tsinghua Science and Technology 2019年第1期24卷 106-122页

作者： Xingshen song yuexiang Yang yu jiang School of Advanced Interdisciplinary Studies National University of Defense Technology College of Computer National University of Defense Technology Northwest Institute of Nuclear Technology

Inverted indexes are widely adopted in the vast majority of information systems. Growing requirements for efficient query processing have motivated the development of various compression techniques with different spacetime characteristics. Although a single encoder yields a relatively stable point in the space-time tradeoff curve,flexibly transforming its characteristic along the curve to fit different information retrieval tasks can be a better way to prepare the index. Recent research comes out with an idea of integrating different encoders within the same index,namely, exploiting access skewness by compressing frequently accessed regions with faster encoders and rarely accessed regions with succinct encoders, thereby improving the efficiency while minimizing the compressed ***, these methods are either inefficient or result in coarse granularity. To address these issues, we introduce the concept of bicriteria compression, which aims to formalize the problem of optimally trading the compressed size and query processing time for inverted index. We also adopt a Lagrangian relaxation algorithm to solve this problem by reducing it to a knapsack-type problem, which works in O(n log n)time and O(n)space, with a negligible additive approximation. Furthermore, this algorithm can be extended via dynamic programming pursuing improved query efficiency. We perform an extensive experiment to show that, given a bounded time/space budget, our method can optimally trade one for another with more efficient indexing and query performance.

关键词： inverted index bicriteria compression Lagrangian relaxation

Cascading failures of overload behaviors using a new coupled network model between edges

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Chinese Physics B 2022年第1期31卷 704-710页

作者： yu-Wei Yan yuan jiang rong-Bin yu song-Qing Yang Cheng Hong School of Information Engineering Nanchang Hangkong UniversityNanchang 330063China

With the development of network science,the coupling between networks has become the focus of complex network ***,previous studies mainly focused on the coupling between nodes,while ignored the coupling between *** propose a novel cascading failure model of two-layer *** model considers the different loads and capacities of edges,as well as the elastic and coupling relationship between *** addition,a more flexible load-capacity strategy is adopted to verify the *** simulation results show that the model is *** networks have different behaviors for the same *** changing the load parameters,capacity parameters,overload parameters,and distribution parameters reasonably,the robustness of the model can be significantly improved.

关键词： cascade failure overload load distribution edge-based

Formation and Relative Stabilities of Core-Shelled L12-Phase Nano-structures in Dilute Al–Sc–Er Alloys

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Acta Metallurgica Sinica(English Letters) 2020年第12期33卷 1627-1634页

作者： Chaomin Zhangi Yong jiang Xiuhua guo Kexing song School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023People's Republic of China School of Materials Science and Engineering Central South UniversityChangsha 410083China Henan Province Key Laboratory of Nonferrous Metal Material Science and Processing Technology Luoyang 471023People's Republic of China Collaborative Innovation Center of Nonferrous Metals Luoyang 471023Henan ProvinceChina Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology Luoyang 471023Henan ProvincePeople's Republic of China

First-principles thermodynamic calculations were carried out at the interface level for understanding the precipitation of coherent L12-phase nano-structures in dilute Al–Sc–Er *** energetics,relevant to bulk substitution,interface formation,interfacial coherent strain and segregation,were calculated and used to evaluate the nucleation and relative stabilities of various possible L12 *** matrix-dissolved solute Er(or Sc)can substitute Sc(or Er)in L12-Al3Sc(or Al3Er).The inter-substitution between L12-Al3Sc and Al3Er is not energy *** L12-Al3(Er x Sc 1.x)precipitates tend to form the Al3Er-core and Al3Sc-shell structure with a sharp core/shell *** possible formation mechanisms were proposed and *** eff ects of Er/Sc ratio and aging temperature on the relative stabilities of L12-phase nanostructures in Al were also discussed.

关键词： Al–Sc–Er alloy L12 phase Core-shell Interface First-principles

Phase formation and crystallization of LiMn_(x)Fe_(1-x)PO_(4)-C olivine material with different Mn^(2+)contents fabricated at lower calcination temperatures

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Rare Metals 2022年第9期41卷 3142-3149页

作者： Guan-Wei Liu Xiang-Jun Zhang song Gong Dan-ping jiang Bing-Xue Liu rong Yang Shi-Gang Lu R&D center for energy storage and vehicle batteries General Research Institute for Nonferrous MetalsBeijing100088China

LiMn_(x)Fe_(1-x)PO_(4)-C cathode materials for lithium ion batteries were synthesized via solid-state method using Li_(2)CO_(3),MnCO_(3),NH_(4)H_(2)PO_(4),FePO_(4) and sucrose as starting raw materials,followed by high-temperature reduction-annealing.A series of calcination experiments at different temperatures reveal that Mn^(2+)-containing materials exhibit a lower temperature for olivine phase formation,for example LiMn_(0.5)Fe_(0.5)PO_(4) olivine phase forms at 275℃,while manganese-free crystalline LiFePO_(4) generally forms at the required temperature of 350℃.Increasing Mn^(2+) content is found to enhance crystallization degree of LiMn_(x)Fe_(1-x)PO_(4) material prepared at lower calcination temperatures.X-ray photoelectron spectroscopy(XPS)results confirm that Mn valence state(+2)remains unchanged up to~250℃ when calcined in ambient *** above-mentioned beneficial effect of manganese on phase formation and crystallization of olivine can be well attributed to the stable nature of Mn^(2+)and its strong propensity to form olivine phases.

关键词： Energy storage materials Solid-state reactions Phase transitions

Facile and Rapid Solid Phase Synthesis of Monodisperse Oligo(1,4-phenyleneethynylene)s

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Chinese Chemical Letters 2005年第6期16卷 719-722页

作者： guo rong LI Xian Hong WANG Ji LI Xiao jiang ZHAO Fo song WANG State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesGraduate School of the Chinese Academy of SciencesChangchun 130022

An extremely facile and rapid solid phase route free of column chromatographic purification for the synthesis of the soluble monodisperse oligo(1, 4-phenyleneethynylene)s up to～60  was presented.

关键词： Solid phase monodisperse oligo(1,4-phenyleneethynylene)s.

The Effects of Farmyard Manure and Mulch on Soil Physical Properties in a Reclaimed Coastal Tidal Flat Salt-Affected Soil

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Journal of Integrative Agriculture 2014年第8期13卷 1782-1790页

作者： ZHANG Jian-bing YANG Jing-song YAO rong-jiang yu Shi-peng LI Fu-rong HOU Xiao-jing State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Dongtai Institute of Tidal Flat Nanjing Branch of the Chinese Academy of Sciences

Careful soil management is important for the soil quality and productivity improvement of the reclaimed coastal tidal flat saline land in northern jiangsu Province, China. Farmyard manure（ FYM） and mulch applications, which affect soil characteristics and plant significantly, are regard as an effective pattern of saline land improvement. As a conventional management in the study region, FYM and mulch are used for the amendment of the new reclaimed tidal flat regularly, but little is known about their effects on soil physical properties functioning. A study was conducted on a typical coastal tidal flat saline land, which was reclaimed in 2005, to evaluate the effects of FYM, polyethylene film mulch（PM）, straw mulch（SM）, FYM combined with PM（FYM＋PM）, FYM combined with SM（FYM＋SM）, on soil hydraulic properties and soil mechanical impedance. CK represented conventional cultivation in study area without FYM and mulch application and served as a control. The experiment, laid out in a randomized complete block design with three replications, was studied in Huanghaiyuan Farm, which specialized in the agricultural utilization for coastal tidal flat. Result showed that capillary water holding capacity（CHC）, saturated water content（SWC）, saturated hydraulic conductivity（ Ks） and bulk density（BD）, cone index（CI） were affected significantly by the FYM and mulch application, especially in the 0-10 cm soil layer. FYM and mulch management increased CHC, SWC and Ks over all soil depth in the order of FYM＋SM〉FYM＋PM〉FYM〉SM〉PM〉CK. With the contrary sequence, BD and CI decreased significantly; however, FYM and mulch application affected BD and CI only in the upper soil layers. CHC, SWC and Ks decreased significantly with the increasing of soil depth, BD and CI, and a significant liner equation was found between CHC, SWC, Ks and BD, CI. With the highest CHC（38.15%）, SWC（39.55%）, Ks（6.00 mm h-1） and the lowest BD（1.26 g cm-3） and CI（2.71 MPa）, the combined management of FYM and SM was reco

关键词： farmyard manure mulch hydraulic property soil mechanical impedance tidal flat northern jiangsu Province

An Exploratory Analysis of Vegetation Strategies to Reduce Shallow Landslide Activity on Loess Hillslopes, Northeast Qinghai-Tibet Plateau, China

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Journal of Mountain Science 2013年第4期10卷 668-686页

作者： HU Xia-song BRIERLEY Gary ZHU Hai-li LI guo-rong FU jiang-tao MAO Xiao-qing yu Qin-qin QIAO Na Department of Geological Engineering Qinghai University Qinghai Institute of Salt Lakes Chinese Academy of Sciences School of Environment University of Auckland Private Bag 92019 Auckland City 1142New Zealand

Heavy summer rainfall induces significant soil erosion and shallow landslide activity on the loess hillslopes of the Xining Basin at the northeast margin of the Qinghai-Tibet Plateau. This study examines the mechanical effects of five native shrubs that can be used to reduce shallow landslide activity. We measured single root tensile resistance and shear resistance, root anatomical structure and direct shear and triaxial shear for soil without roots and five root- soil composite systems. Results show that Atriplex canescens （Pursh） Nutt. possessed the strongest roots, followed by Caragana korshinskii Kom., Zygophyllum xanthoxylon （Bunge） Maxim., Nitraria tangutorum Bobr. and Lycium chinense Mill. Single root strength and shear resistance relationships with root diameter are characterized by power or exponential relations, consistent with the Mohr- Coulomb law. Root mechanical strength reflects their anatomical structure, especially the percentage of phloem and xylem cells, and the degree and speed of periderm lignifications. The cohesion force of root- soil composite systems is notably higher than that of soil without roots, with increasing amplitudes of cohesion force for A. canescens, C. korshinskii, Z. xanthoxylon, N. tangutorurn and L. chinense of 75.9%, 75.1%, 36.2%, 24.6% and 17.0 % respectively. When subjected to shear forces, the soil without root samples show much greater lateral deformation thanthe root-soil composite systems, reflecting the restraining effects of roots. Findings from this paper indicate that efforts to reduce shallow landslides in this region by enhancing root reinforcement will be achieved most effectively using A. canescens and C. korshinskii.

关键词： Arid environments Shallow landslide Vegetative hillslope protection Root-soil compositesystems Tensile strength Root reinforcement

The influence of plant root system architectural properties upon the stability of loess hillslopes,Northeast Qinghai,China

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Journal of Mountain Science 2016年第5期13卷 785-801页

作者： FU jiang-tao HU Xia-song BRIERLEY Gary QIAO Na yu Qin-qin LU Hai-jing LI guo-rong ZHU Hai-li Qinghai Institute of Salt Lakes Chinese Academy of SciencesXiningQinghai810008China University of ChineseAcademy of Sciences Beijing100049China Department of C-eological Engineering Oinghai UniversityXiningQinghai810016China School of Environment University of AucklandPrivate Bag 92019Auckland City 1142New Zealand

To investigate the influence of root system architectural properties of three indigenous （cold- adapted） shrubs on the hillslope stability of loess deposits in the Xining Basin, northeast part of Qinghai-Tibet Plateau （QTP）, indoor direct shear tests have been conducted on the remolded rooted soil of three shrubs. Test results show that root system architectural indices （root area ratio （RAR）, root length density （RLD） and root density （RD）） of the shrubs decline with depth and the relationship between RAR, RD and depth is exponential, while a power relationship describes the relationship between RLD and depth. The cohesion force of remolded rooted soil for the shrubs initially increases with depth, but it then demonstrates a slightly decreasing trend, which can be described with a power relationship. Power relationships also describe relationships between cohesion force and RAR, RLD and RD for the shrubs. As the growth period increases from lO to 17 months, the incremental increase in RAR is 48.32% ~ 21o.25% for Caragana korshinskii Kom and 0.56% ~ 166.85% for Zygophyuum xanthoxylon （Bunge） Maxim. This proportional increase is notably larger than that for RLD and RD. The increment in RAR is marginally greater for C. korshinskff than it is for Z. xanthoxylon. Correspondingly, the cohesion force incremental rates of remolded rooted soil for C. korshinskii and Z. xanthoxylon are 12.41% ~ 25.22% and 3.45% ~ 17.33% respectively. Meanwhile, as root content increases, the contribution by roots to cohesion force increases markedly until a threshold condition is reached.

关键词： Cold region Semiarid region Soil reinforcement Hillslope stability Root system architectural indices Plateau

Quantized dynamic output feedback control for networked control systems

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Journal of Systems Engineering and Electronics 2010年第6期21卷 1025-1032页

作者： Chong jiang Dexin Zou Qingling Zhang song guo Institute of Systems Science Northeastern University Shenyang 110004 P. R. China Key Laboratory of Integrated Automation of Process Industry Northeastern University Shenyang 110004 E R. China Research Center of Sports Social Science Shenyang Sports University Shenyang 110102 P. R. China

The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a novel networked control system model is described. This model includes many networkinduced features, such as multi-rate sampled-data, quantized signal, time-varying delay and packet dropout. By constructing suitable Lyapunov-Krasovskii functional, a less conservative stabilization criterion is established in terms of linear matrix inequalities. The quantized control strategy involves the updating values of the quantizer parameters μi（i = 1, 2）（μi take on countable sets of values which dependent on the information of the system measurement outputs and the control inputs）. Furthermore, a numerical example is given to illustrate the effectiveness of the proposed method.

关键词： networked control systems sampled-data linear matrix inequalities quantized dynamic output feedback.