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On a Class of Two-Dimensional Projectively Flat Finsler Metrics with Constant Flag Curvature

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Acta Mathematica Sinica,English Series 2013年第5期29卷 959-974页

作者： Guo jun yang Department of Mathematics Sichuan University

In this paper, we study a special class of two-dimensional Finsler metrics defined by a Riemannian metric and 1-form. We classify those which are locally projectively flat with constant flag curvature.

关键词： (α β)-Metric projectively flat constant flag curvature

Enhanced primary treatment of low-concentration municipal wastewater by means of bio-flocculant Pullulan

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 719-723页

作者： yang Kai yang Xiao-jun yang Mo School of Civil Engineering Wuhan University Wuhan 430072 China School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

Jar tests were conducted to investigate the performance of enhanced primary treatment processes for low-concentra-tion municipal wastewater from South China by using composite flocculant combined with bio-flocculants Pullulan and poly-aluminum-chloride (PAC). The optimum dosage for composite flocculant and conditions for flocculation were determined. The experimental results indicated that composite flocculant had high efficiency for removing over 95% of turbidity, over 58% of CODCr (chemical oxygen demand determined with potassium dichromate), over 91% of TP (total phosphate), and over 15% of NH3-N. Moreover, it could improve sludge settling and dehydration properties, and decrease the treatment cost.

关键词： Bio-flocculant Pullulan Enhanced primary treatment

Construction of 2_Ⅲ^(m-(m-k)) Designs with the Maximum Number of Clear Two-factor Interactions

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Acta Mathematicae Applicatae Sinica 2007年第1期23卷 107-112页

作者： Gui-jun yang Department of Statistics Tianjin University of Finance and Economics Tianjin 300222 China

It is useful to know the maximum number of clear two-factor interactions in a 2Ⅲ^[m-（m-k）] design. This paper provides a method to construct a 2Ⅲ^[m-（m-k）] design with the maximum number of clear two-factor interactions. And it is proved that the resulting designs have more dear two-factor interactions than those constructed by Tang et al. Moreover, the designs constructed are shown to have concise grid representations.

关键词： Resolution minimum aberration clear two-factor interaction

Digital cancellation of multi-band passive inter-modulation based on Wiener-Hammerstein model

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Digital Communications and Networks 2024年第4期10卷 1189-1197页

作者： Jinxiang Liu Xiaotao Zhang jun yang Huiping yang School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China Huawei Technologies Co. Ltd.Dongguan 523808China School of Electronic and Information Engineering South China Normal UniversityGuangzhou 510631China

Utilizing multi-band and multi-carrier techniques enhances throughput and capacity in Long-Term Evolution(LTE)-Advanced and 5G New Radio(NR)mobile ***,these techniques introduce Passive Inter-Modulation(PIM)interference in Frequency-Division Duplexing(FDD)*** this paper,a novel multi-band Wiener-Hammerstein model is presented to digitally reconstruct PIM interference signals,thereby achieving effective PIM Cancellation(PIMC)in multi-band *** the model,transmitted signals are independently processed to simulate Inter-Modulation Distortions(IMDs)and Cross-Modulation Distortions(CMDs).Furthermore,the Finite Impulse Response(FIR)filter,basis function generation,and B-spline function are applied for precise PIM product estimation and generation in multi-band *** involving 4 carrier components from diverse NR frequency bands at varying transmitting powers validate the feasibility of the model for multi-band PIMC,achieving up to 19 dB in PIMC *** to other models,this approach offers superior PIMC performance,exceeding them by more than 5 dB in high transmitting power ***,its lower sampling rate requirement reduces the hardware complexity associated with implementing multi-band PIMC.

关键词： Passive inter-modulation Frequency-division duplexing Nonlinear distortion Digital cancellation Spline interpolation Wiener-Hammerstein model

Structural and functional variations of phytoplankton communities in the face of multiple disturbances

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Journal of Environmental Sciences 2021年第2期33卷 287-297页

作者： jun R.yang Xiaoqing Yu Huihuang Chen Yi-Ming Kuo jun yang Engineering Research Center of Ecology and Agricultural Use of wetland(Ministry of Education)College of Agriculture Yangtze UniversityJingzhou 434025China Aquatic Ecohealth Group Fujian Key Laboratory of Watershed EcologyKey Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China School of Environmental Studies China University of GeosciencesWuhan 430074China

The global decline of freshwater biodiversity caused by climate change and human activities are supposed to disrupt ecosystem services related to water quality and alter the structure and function of aquatic communities across space and time,yet the effects of the combination of these factors on plankton community ecosystem has received relatively little *** study aimed to explore the impacts of disturbances(*** activity,temperature,precipitation,and water level)on phytoplankton community structure(*** evenness and community composition)and function(*** use efficiency)in four subtropical reservoirs over 7 years from 2010 to *** results showed that community turnover(measured as community dissimilarity)was positively related to disturbance frequency,but no significant correlation was found between phytoplankton biodiversity(***)and disturbance *** resource use efficiency(RUE=phytoplankton biomass/total phosphorus)was increased with a higher frequency of disturbance with an exception of *** RUE of Cyanobacteria and diatoms showed significantly negative correlations with their community evenness,while the RUE of Chlorophyta exhibited a positive correlation with their community *** suggest that multiple environmental disturbances may play crucial roles in shaping the structure and functioning of plankton communities in subtropical reservoirs,and mechanism of this process can provide key information for freshwater uses,management and conservation.

关键词： Algae Biodiversity Community ecology Plankton Resource use efficiency Subtropical reservoir

Numerical Study of Pressure Pulsation of Centrifugal Pumps with the Compressible Mode

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Journal of Thermal Science 2019年第1期28卷 106-114页

作者： yang jun LIU jun LIU Xiaohua XIE Tian School of Energy and Power Engineering University of Shanghai for Science and Technology School of Aeronautics and Astronautics Shanghai Jiao Tong University

The compressible effect of water is often neglected in the simulation of hydraulic machinery. However, based on experimental and numerical study, it is found that the compressibility of water could influence the magnitude of the pressure pulsation at some frequency in the pump. Therefore, in order to investigate the influence of water compressibility, compressible model is established by using Tait equation. The internal flow of centrifugal pump under different conditions is calculated by this model. The calculated results are compared with the incompressible results, and it is indicated that the compressibility of water has little effect on the performance parameters. But it affects the amplitude of pressure fluctuations at some discrete frequency, especially at the outlet of impeller and volute tongue where significant jet-wake and rotor/stator interaction appears respectively. Meanwhile, water compressibility makes greater influence on the flow pulsation under off-design condition. Therefore, it is necessary to consider the compressibility of working medium in the numerical simulation of unsteady flow in centrifugal pumps, especially in area with strong unsteady flow and at off-design condition.

关键词： water compressibility Tait equation unsteady flow pressure pulsations centrifugal pump

Reduced-Order GPIO Based Dynamic Event-Triggered Tracking Control of a Networked One-DOF Link Manipulator Without Velocity Measurement

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 725-734页

作者： Jiankun Sun jun yang Shihua Li School of Automation Southeast UniversityNanjing 210096China IEEE School of Automation Southeast UniversityKey Laboratory of Measurement and Control of CSEMinistry of EducationNanjing 210096China

In networked robot manipulators that deeply integrate control, communication and computation, the controller design needs to take into consideration the limited or costly system resources and the presence of disturbances/uncertainties. To cope with these requirements, this paper proposes a novel dynamic event-triggered robust tracking control method for a onedegree of freedom(DOF) link manipulator with external disturbance and system uncertainties via a reduced-order generalized proportional-integral observer(GPIO). By only using the sampled-data position signal, a new sampled-data robust output feedback tracking controller is proposed based on a reduced-order GPIO to attenuate the undesirable influence of the external disturbance and the system uncertainties. To save the communication resources, we propose a discrete-time dynamic event-triggering mechanism(DETM), where the estimates and the control signal are transmitted and computed only when the proposed discrete-time DETM is violated. It is shown that with the proposed control method, both tracking control properties and communication properties can be significantly improved. Finally, simulation results are shown to demonstrate the feasibility and efficacy of the proposed control approach.

关键词： Dynamic event-triggering mechanism(DETM) external disturbance and system uncertainties networked robot manipulator reduced-order generalized proportional-integral observer(GPIO) robust control

A Model-Based Unmatched Disturbance Rejection Control Approach for Speed Regulation of a Converter-Driven DC Motor Using Output-Feedback

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IEEE/CAA Journal of Automatica Sinica 2022年第2期9卷 365-376页

作者： Lu Zhang jun yang Shihua Li School of Automation Southeast UniversityKey Laboratory of Measurement and Control of Complex Systems of EngineeringMinistry of Education IEEE Department of Aeronautical and Automotive Engineering Loughborough University

The speed regulation problem with only speed measurement is investigated in this paper for a permanent magnet direct current(DC)motor driven by a buck *** lumping all unknown matched/unmatched disturbances and uncertainties together,the traditional active disturbance rejection control(ADRC)approach provides an intuitive solution for the problem under ***,for such a higher-order disturbed system,the increase of poles for the extended state observer(ESO)therein will lead to drastically growth of observer gains,which causes severe noise *** paper aims to propose a new model-based disturbance rejection controller for the converter-driven DC motor system using *** of estimating lumped disturbances directly,a new observer is constructed to estimate the desired steady state of control signal as well as errors between the real states and their desired steady-state ***,a controller with only speed measurement is proposed by utilizing the *** performance of the proposed method is tested through experiments on *** is further shown via numerical calculations and experimental results that the poles of the observer within the proposed control approach can be largely increased without significantly increasing magnitude of the observer gains.

关键词： Bandwidth widening converter-driven direct current(DC)motor disturbance observer model-based disturbance rejection speed regulation

Random testing for system-level functional verification of system-on-chip

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1378-1383页

作者： Ma Qinsheng Cao yang yang jun Wang Min School of Electronic Information Wuhan Univ. Wuhan 430079 P. R. China State Key Lab. of Software Engineering Wuhan Univ. Wuhan 430072 P. R. China Second Dept. Commanding Communications Academy Wuhan 430010 P. R. China

In order to deal with the limitations during the register transfer level verification, a new functional verification method based on the random testing for the system-level of system-on-chip is *** validity of this method is proven ***, testcases are generated according to many approaches of ***, the testbench for the system-level verification according to the proposed method is designed by using advanced modeling ***, under the circumstances that the testbench generates testcases quickly, the hardware/software co-simulation and co-verification can be implemented and the hardware/software partitioning planning can be evaluated *** comparison method is put to use in the evaluation approach of the testing *** evaluation result indicates that the efficiency of the partition testing is better than that of the random testing only when one or more subdomains are covered over with the area of errors, although the efficiency of the random testing is generally better than that of the partition *** experimental result indicates that this method has a good performance in the functional coverage and the cost of testing and can discover the functional errors as soon as possible.

关键词： VLSI circuit verification random process function testing system-on-chip system-level.