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A Levenberg–Marquardt Method for Solving the Tensor Split Feasibility Problem

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Journal of the Operations Research Society of China 2021年第4期9卷 797-817页

作者： Yu-Xuan Jin Jin-Ling zhao School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China

This paper considers the tensor split feasibility *** C and Q be non-empty closed convex set and A be a semi-symmetric *** tensor split feasibility problem is to find x∈C such that Axm−1∈*** we simply take this problem as a special case of the nonlinear split feasibility problem,then we can directly get a projection method to solve ***,applying this kind of projection method to solve the tensor split feasibility problem is not so *** we propose a Levenberg–Marquardt method to achieve higher *** analyses are conducted,and some preliminary numerical results show that the Levenberg–Marquardt method has advantage over the common projection method.

关键词： Tensor Split feasibility problem Semi-symmetric Projection Levenberg-Marquardt method

A Novel Vertical Handoff Algorithm with Dynamic Weights in Wireless Heterogeneous Networks

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China Communications 2010年第5期7卷 70-76页

作者： Liu Xia zhao Fangming Jiang Lingge College of Merchant Marine Shanghai Maritime University Shanghai 200135 P. R. China School of Electronic and Electrical Engineering Shanghai Second Polytechnic University Shanghai 201209 P. R. China Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China

In order to enhance the quality of vertical handoff in an overlay wireless network, multiple attributes are taken into account when optimizing the vertical handoff decision including user-based and network-based QoS factors. In this paper, we develop a novel vertical handoff algorithm in an integrated 3G cellular and Wireless LAN networks. The proposed algorithm can adjust the weight of each QoS attribute dynamically as the networks change, trace the network condition and choose the optimal access point at transient regions. Simulation results show that this algorithm is able to provide accurate handoff decision, resulting in small unnecessary handoff numbers, good performance of throughput and handoff delay in heterogeneous environments.

关键词： vertical handoff multiple attrbute dynamic weight heterogeneous networks

Evaluation of the Momentum Closure Schemes in MPAS-Ocean

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Journal of Ocean University of China 2018年第2期17卷 227-243页

作者： zhao Shimei LIU Yudi LIU Wei College of Meteorology and Oceanography Nanjing University of Science and Technology

In order to compare and evaluate the performances of the Laplacian viscosity closure, the biharmonic viscosity closure, and the Leith closure momentum schemes in the MPAS-Ocean model, a variety of physical quantities, such as the relative reference potential energy(RPE) change, the RPE time change rate(RPETCR), the grid Reynolds number, the root mean square(RMS) of kinetic energy, and the spectra of kinetic energy and enstrophy, are calculated on the basis of results of a 3D baroclinic periodic channel. Results indicate that: 1) The RPETCR demonstrates a saturation phenomenon in baroclinic eddy tests. The critical grid Reynolds number corresponding to RPETCR saturation differs between the three closures: the largest value is in the biharmonic viscosity closure, followed by that in the Laplacian viscosity closure, and that in the Leith closure is the smallest. 2) All three closures can effectively suppress spurious dianeutral mixing by reducing the grid Reynolds number under sub-saturation conditions of the RPETCR, but they can also damage certain physical processes. Generally, the damage to the rotation process is greater than that to the advection process. 3) The dissipation in the biharmonic viscosity closure is strongly dependent on scales. Most dissipation concentrates on small scales, and the energy of small-scale eddies is often transferred to large-scale kinetic energy. The viscous dissipation in the Laplacian viscosity closure is the strongest on various scales, followed by that in the Leith closure. Note that part of the small-scale kinetic energy is also transferred to large-scale kinetic energy in the Leith closure. 4) The characteristic length scale L and the dimensionless parameter Г in the Leith closure are inherently coupled. The RPETCR is inversely proportional to the product of Г and L. When the product of Г and L is constant, both the simulated RPETCR and the inhibition of spurious dianeutral mixing are the same in all tests using the Leith closure

关键词： 3D baroclinic eddy momentum closure grid Reynolds number the reference potential energy(RPE) baroclinic adjustment kinetic energy enstrophy

NUAT T-splines of odd bi-degree and local refinement

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Applied Mathematics(A Journal of Chinese Universities) 2014年第4期29卷 410-421页

作者： DUAN Xiao-juan WANG Guo-zhao Department of Mathematics Zhejiang University

This paper presents a new kind of spline surfaces, named non-uniform algebraic- trigonometric T-spline surfaces （NUAT T-splines for short） of odd hi-degree. The NUAT T- spline surfaces are defined by applying the T-spline framework to the non-uniform algebraic- trigonometric B-spline surfaces （NUAT B-spline surfaces）. Based on the knot insertion algorithm of the NUAT B-splines, a local refinement algorithm for the NUAT T-splines is given. This algorithm guarantees that the resulting control grid is a T-mesh as the original one. Finally, we prove that, for any NUAT T-spline of odd hi-degree, the linear independence of its blending functions can be determined by computing the rank of the NUAT T-spline-to-NUAT B-spline transformation matrix.

关键词： odd bi-degree non-uniform algebraic-trigonometric T-spline local refinement blending function,linear independence.

INVESTIGATION OF THE MEAN-FLOW SCALING AND TRIPPING EFFECT ON FULLY DEVELOPED TURBULENT PIPE FLOW

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Journal of Hydrodynamics 2003年第1期15卷 14-22页

作者： zhaoJin-yin XieMao-zhao DurstF. DepartmentofPowerEngineering DalianUniversityofTechnologyDalian116024China InstituteofFluidMechanics ErlangenUniversity91529ErlangenGermany

Fully developed turbulence measurements in pipe flow were made in theReynolds number range from 10 X 10~3 to 350 X 10~3 with hot-wire anemometer and a Pilot *** were made with the experimental results of previous researchers. The mean velocityprofile and the turbulent intensity in the experiments indicate that for the mean velocity profile,in the fully developed turbulent pipe flow, von Karman's constant κ is a function of the Reynoldsnumber, i. e. κ increases slowly with the Reynolds number. For turbulent pipe flow, the outer limitdepends on whether the Kdrmdn number R^+ is greater or less than 850 in the centerline velocityprofile: a log law exists for 850 < R^+< 1750 in the experiment, and von Karman' s constant κ isshown to be 0. 408. Under the effects of the test trip at the inlet, fully developed turbulence wasobtained in pipe flow at lower Reynolds number when the entrance length (x/D) was larger than 40. Inthe experiment it was also found that turbulence quantities in pipe flow remain independent of theupstream conditions when the trip blockage ratio is higher than 20%, and the comparison with channelwater flow was also performed.

关键词： turbulent pipe flow velocity profile overlap region tripping effect

Theory and application of nonlinear river dynamics

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International Journal of Sediment Research 2014年第3期29卷 285-303页

作者： Yu-chuan BAI zhao-yin WANG State Kev Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University State Kev Laboratory of Hydroscience and Engineering Tsinghua University

A theoretical model for river evolution including riverbed formation and meandering pattern formation is presented in this *** on nonlinear mathematic theory,the nonlinear river dynamic theory is set up for river dynamic *** core content includes the stability and tropism characteristics of flow motion in river and river selves’ *** stability of river dynamic process depends on the response of river selves to the external disturbance,if the disturbance and the resulting response will eventually attenuate,and the river dynamics process can be restored to new equilibrium state,the river dynamic process is known as stable;otherwise,the river dynamic process is *** river dynamic process tropism refers to that the evolution tendency of river morphology after the *** an application of this theory,the dynamical stability of the constant curvature river bend is calculated for its coherent vortex disturbance and *** addition,this paper discusses the nonlinear evolution of the river peristaltic process under a large-scale disturbance,showing the nonlinear tendency of river dynamic processes,such as river filtering and butterfly effect.

关键词： River Dynamic process Reservoir Nonlinear Long term evolution River dynamics

A new source extraction algorithm for optical space debris observation

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Research in Astronomy and Astrophysics 2013年第5期13卷 604-614页

作者： Rong-Yu Sun Chang-Yin zhao Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory of Space Object and Debris Observation Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences

Specific challenges arise in the task of real-time automatic data reduction of optical space debris observations. Here we present an automatic technique that optimally detects and measures the sources from images of optical space debris ob- servations. We show that highly reliable and accurate results can be obtained on most images produced by our specific sensors, and due to optimizations, the whole pipeline works fast and efficiently. Tests demonstrate that the technique performs better than SExtractor from the point of view of fast and accurate detection, therefore it is well suited for data reduction of optical space debris observations.

关键词： techniques: image processing -- space vehicles -- astrometry

Pollution Characteristics and Health Risk Assessment of Heavy Metals in PM_2.5 during Winter in the Suburb of Cangzhou, China

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Journal of Geoscience and Environment Protection 2022年第8期10卷 122-136页

作者： Jian Wang Zhenxia Chen Yaheng Pang Yanan zhao Yufeng Mao na Mao Mei Xu College of Chemistry and Chemical Engineering Cangzhou Normal University Cangzhou China Cangzhou Municipal Research Institute of Environmental Protection Cangzhou China

The heavy metals in atmospheric fine particles are of great concern to human health. To understand the pollution characteristics and health risks of heavy metals in particulate matter with an aerodynamic equivalent diameter ≤2.5 μm (PM2.5) during winter in the suburb of Cangzhou, PM2.5 samples were collected with an intelligent medium-flow atmospheric particulate matter sampler from January to February 2019. The Fe, Cu, Mn, Pb and Zn contents in PM2.5 were determined via inductively coupled plasma optical emission spectrometry (ICP-OES). The sources and health risks of heavy metals in PM2.5 were analysed via the enrichment factor (EF) method and the United States Environmental Protection Agency (US EPA) health risk assessment model. The results showed that the average PM2.5 concentration in the suburb of Cangzhou reached 71.6 μg/m3, ranging from 23.7 to 169.5 μg/m3. The exceeding standard rate was 29.4% during the sampling period. The PM2.5 concentration during the nighttime was higher than that during the daytime. The heavy metal concentrations in PM2.5 decreased in the order of Fe > Mn > Zn > Cu > Pb, and the Fe, Mn, Pb and Zn concentrations decreased in the order of clean days nalysis revealed that Zn, Pb and Cu were significantly enriched, and Pb was highly enriched on heavy pollution days with increasing pollution degree. The enrichment level of heavy metals during the nighttime was higher than that during the daytime. Health risk assessment demonstrated that Mn posed non-carcinogenic risks to both adults and children, following the sequence of clean days < pollution days < heavy pollution days. Pb posed a carcinogenic risk to

关键词： Fine Particles Enrichment Factor Atmospheric Pollution Different Pollution Levels

Novel intelligent devices: Two-dimensional materials based memristors

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Frontiers of physics 2022年第2期17卷 83-85页

作者： Lena Du Zhongchang Wang Guozhong zhao Department of Physics Capital Normal UniversityBeijing 100048China International Iberian nanotechnology Laboratory(INL)Avenida Mestre JoséVeiga s/n Braga 4715-330Portugal

Two-dimensional(2D)materials with atomic thickness,non-volatile resistive switching feature and compatibility with the semiconducting technology are naturally a good media of memristors.2D materials-based memristors with excellent performance,low-power consumption and high integration density can be integrated with other circuit components to implement the complicate logic computing,which will become a key driving force for the development of artificial intelligence.

关键词： artificial memristor driving