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Existence of Positive Solutions to Fourth Order Quasilinear Boundary Value Problems

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Acta Mathematica Sinica,English Series 2006年第6期22卷 1825-1830页

作者： zhan Bing bai Wei Gao GE Institute of Mathematics Shandong University of Science and Technology Qingdao 266510 P.R. China Department of Applied Mathematics Beijing Institute of Technology Beijing 100081 P.R. China

In this paper, we generalize the fixed point theorem of cone expansion and compression of norm type to the theorem of functional type. As an application, the existence of positive solutions for some fourth-order beam equation boundary value problems is obtained. The emphasis is put on that the nonlinear term is dependent on all lower order derivatives.

关键词： fourth-order boundary value problem fixed point theorem positive solution

Software-as-a-service(SaaS): perspectives and challenges

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Science China(Information Sciences) 2014年第5期57卷 5-19页

作者： TSAI WeiTek bai XiaoYing HUANG Yu School of Computing Informatics and Decision Systems Engineering Arizona State University Department of Computer Science and Technology Tsinghua National Lab of Information Science and TechnologyTsinghua University

Software-as-a-service(SaaS)has received significant attention recently as one of three principal components of cloud computing,and it often deals with applications that run on top of a platform-as-a-service(PaaS)that in turn runs on top of infrastructure-as-a-service(IaaS).This paper provides an overview of SaaS including its architecture and major technical issues such as customization,multi-tenancy architecture,redundancy and recovery mechanisms,and ***,a SaaS system can have architecture relating to a database-oriented approach,middleware-oriented approach,service-oriented approach,or PaaS-oriented *** SaaS customization strategies can be used from light customization with manual coding to heavy customization where the SaaS system and its underlying PaaS systems are customized ***-tenancy architecture is an important feature of a SaaS and various trade-offs including security isolation,performance,and engineering effort need to be *** is important for a SaaS system to have multi-level redundancy and recovery mechanisms,and the SaaS system needs to coordinate these with the underlying PaaS ***,SaaS scalability mechanisms include a multi-level architecture with load balancers,automated data migration,and software design strategies.

关键词： software-as-a-service SaaS architecture customization multi-tenancy architecture redundancy and recovery scalability

Effects of Elevated Air Temperatures on Soil Thermal and Hydrologic Processes in the Active Layer in an Alpine Meadow Ecosystem of the Qinghai-Tibet Plateau

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Journal of Mountain Science 2012年第2期9卷 243-255页

作者： bai Wei WANG Genxu LIU Guangsheng School of Environmental and Municipal Engineering Lanzhou Jiaotong UniversityLanzhou 730070China College of Resource and Environmental Science Lanzhou UniversityLanzhou 730000China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

In this study,effects of elevated air temperatures on thermal and hydrologic process of the shallow soil in the active layer were investigated. Open-top chambers(OTCs)were utilized to increase air temperatures 1-2℃ in OTC-1 and 3-5℃ in OTC-2 in the alpine meadow ecosystem on the Qinghai- Tibetan *** show that the annual air temperatures under OTC-1 and OTC-2 were 1.21℃ and 3.62℃ higher than the Control,*** entirely-frozen period of shallow soil in the active layer was shortened and the fully thawed period was prolonged with temperature *** maximum penetration depth and duration of the negative isotherm during the entirely-frozen period decreased, and soil freezing was retarded in the local scope of the soil profile when temperature ***, the positive isotherm during the fully-thawed period increased,and the soil thawing was *** moisture under different manipulations decreased with the temperature increase at the same depth. During the early freezing period and the early fully- thawed period,the maximum soil moisture under the Control manipulation was at 0.2 m deep,whereas under OTC-1 and OTC-2 manipulations,the maximum soil moisture were at 0.4-0.5 m deep. These results indicate that elevated temperatures led to a decrease of the moisture in the surface *** coupled relationship between soil temperature and moisture was significantly affected by the temperature *** the freezing and thawing processes, the soil temperature and moisture under different manipulations fit the regression model given by the equationθV=a/{1+exp[b(TS+c)]}+d.

关键词： Thermal and hydrologic process Temperature Open-top chambers Alpine meadow Qinghai-Tibetan Plateau

Review and suggestions for estimating particulate organic carbon and dissolved organic carbon inventories in the ocean using remote sensing data

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Acta Oceanologica Sinica 2014年第1期33卷 1-10页

作者： PAN Delu LIU Qiong bai Yan State Key Laboratory of Satellite Ocean Environment Dynamics the Second Institute of Oceanography State Oceanic Administration National Marine Environmental Forecasting Center State Oceanic Administration

Dissolved organic carbon（DOC） and particulate organic carbon（POC） are basic variables for the ocean carbon *** of the distribution and inventory of these variables is important for a better estimation and understanding of the global carbon *** to its considerable advantages in spatial and temporal coverage,remote sensing data provide estimates of DOC and POC inventories,which are able to give a synthetic view for the distribution and transportation of carbon *** estimate organic carbon inventories using remote sensing involves integration of the surface concentration and vertical profile models,and the development of these models is critical to the accuracy of ***,the distribution and control factors of DOC and POC in the ocean first are briefly summarized,and then studies of DOC and POC inventories and flux estimations are reviewed,most of which are based on field data and few of which consider the vertical distributions of POC or *** is some research on the estimation of POC inventory by remote sensing,mainly in the open ocean,in which three kinds of vertical profile models have been proposed：the uniform,exponential decay,and Gauss ***,research on remote-sensing estimation of the DOC inventory remains lacking.A synthetic review of approaches used to estimate the organic carbon inventories is offered and the future development of methods is discussed for such estimates using remote sensing data in coastal waters.

关键词： ocean carbon inventory dissolved organic carbon particulate organic carbon remote sensing

Modeling and Tracking Control for Piezoelectric Actuator Based on a New Asymmetric Hysteresis Model

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IEEE/CAA Journal of Automatica Sinica 2017年第4期4卷 782-791页

作者： Geng Wang Guoqiang Chen Hong zhou Fuzhong bai Department of Mechanical and Power Engineering Henan Polytechnic University Laboratory on Adaptive Optics Institute of Optics and Electronics Chinese Academy of Sciences College of Mechanical Engineering Inner Mongolia University of Technology

This paper presents a new asymmetric hysteresis model and its application in the tracking control of piezoelectric actuators. The proposed model is based on a coupled-play operator which can avoid the conventional Prandtl-Ishlinskii(CPI)model's defects, i.e., the symmetric property. The high accuracy for modeling asymmetric hysteresis is validated by comparing simulation results with experimental measurements. In order to further evaluate the performance of the proposed model in closed-loop tracking application, two different hybrid control methods which experimentally demonstrate their performance under the same operating conditions, are compared to validate that the hybrid control strategy with proposed hysteresis model can mitigate the hysteresis more effectively and achieve better tracking precision. The experimental results demonstrate that the proposed modeling and tracking control strategy can realize efficient control of piezoelectric actuator.

关键词： Asymmetric hysteresis model motion control piezoelectric actuator precise tracking

Full friendly index sets of mCn

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Frontiers of Computer Science 2022年第3期16卷 95-99页

作者： Yurong JI Jinmeng LIU Yujie bai Shufei WU School of Mathematics and Information Science Henan Polytechnic UniversityJiaozuo 454003China Basic Department Henan College of Industry and Information TechnologyJiaozuo 454003China

Let G be a connected simple graph with vertex set V(G)and edge set E(G).A binary vertex labeling f:V(G)→z2,is said to be friendly if the number of vertices with different labels differs by at most *** vertex friendly labeling/induces an edge labeling f*E(G)→z2,defined by f*(xy)=f(x)+f(y)for each xy∈E(G).Let er(i)=\{e∈E(G):f*(e)=i}|.The full friendly index set of G,denoted by FFI(G),is the set{ef*(1)-ep(0):f is friendly}.In this paper,we determine the full friendly index set of a family of cycle union graphs which are edge subdivisions of P2×Pn.

关键词： vertex labeling friendly labeling full friendly index set partition bisection

High Velocity Electric Arc Sprayed Fe-Al-Nb-B Composite Coating and Its Wear Behavior

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Acta Metallurgica Sinica(English Letters) 2013年第3期26卷 313-320页

作者： Yongxiong CHEN Xiubing LIANG Jinyuan bai Binshi XU National Engineering Research Center for Mechanical Product Remanufacturing Academy of Armored Forces Engineering National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering

A type of Fe-Al-Nb-B cored wire was designed and the coating was prepared using a robot-based electric wire arc spraying process. The Fe-Al binary cored wire and coating were also prepared as comparison. The phase composition and structure of the coatings were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM） coupled with energy dispersive X-ray spectroscopy （EDS） and transmission electron microscopy （TEM）. The coating tribological properties were evaluated with the micromotion wear tester under different conditions. The results show that, although typical lamellar structure was performed for both the arc sprayed Fe-Al-Nb-B coating and Fe-Al coating, the structure composition, mechanical and wear properties of the former are quite different from those of latter. The Fe-Al-Nb-B coating is a typical composite coating, which is distributed inhomogeneously with α-Fe crystalline, FeAl and Fe3Al intermetallics, amorphous and nanocrystallines as well as locally existed oxide phases. As a result, the mircrohardness and wear resistance of the Fe-Al-Nb-B composite coating increased significantly. Finally the mechanism of the coating wear resistant behavior was discussed based on the experimental results such as friction coefficient, two dimensional and three dimensional worn surface profiles.

关键词： Fe-Al-Nb-B coating Structure High velocity electric arc spraying Wear resistance

A Kind of Unified Strict Efficiency via Improvement Sets in Vector Optimization

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Journal of the Operations Research Society of China 2018年第4期6卷 557-569页

作者： Hui Guo Yan-Qin bai Department of Mathematics Chongqing Normal UniversityChongqing 401331China College of Sciences Shanghai UniversityShanghai 200444China

In this paper,we propose a kind of unified strict efficiency named E-strict efficiency via improvement sets for vector *** kind of efficiency is shown to be an extension of the classical strict efficiency andε-strict efficiency and has many desirable *** also discuss some relationships with other properly efficiency based on improvement sets and establish the corresponding scalarization theorems by a base-functional and a nonlinear ***,some examples are given to illustrate the main conclusions.

关键词： E-strict efficiency Improvement sets Linear scalarization Nonlinear scalarization Vector optimization

Anti-saturation fault-tolerant adaptive torsional vibration control with fixed-time prescribed performance for rolling mill main drive system

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Journal of Iron and Steel Research International 2024年第3期31卷 660-669页

作者： Shuang Liu Chen Du Cong zhang zhen-hua bai Key Lab of Industrial Computer Control Engineering of Hebei Province Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter ***,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the ***,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter *** on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation *** to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric ***,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.

关键词： Fixed-time prescribed performance Control input saturation Actuator fault Unknown time-varying gain Adaptive control Asymmetric constraint