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Wetland and habitat dynamics in the evolving landscape of the Middle Yangtze River Basin

Journal of Geographical Sciences 2025年第1期35卷 88-111页

作者： YANG Peng SUN Kaiya ZHU Yanchao XIA Jun HUANG Heqing SONG Jingxia SHI Xiaorui LU Xixi Hubei Key Laboratory of Regional Ecology and Environmental Change School of Geography and Information Engineering China University of Geosciences department of Geography National University of Singapore State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

Wetlands play a critical role in the global environment. The Middle Yangtze River Basin(MYRB), known for its abundant wetland resources, has experienced notable changes resulting from the complex interplay of environmental factors. Therefore, we investigated the spatiotemporal characteristics of wetland ecological quality in the MYRB from 2001 to *** the random forest(RF) regression algorithm and patch-generated land-use simulation(PLUS) model, we forecasted variations in wetland habitat quality and their determinants under the Shared Socioeconomic Pathway-Representative Concentration Pathway(SSPRCP) framework from 2035 to 2095. The main findings are as follows:(1) The RF algorithm was optimal for land-use and land-cover(LULC) classification in the MYRB from 2001 to 2020,when notable changes were observed in water bodies and buildings. However, the forested area exhibited an increase and decrease of 3.9% and 1.2% under the SSP1-2.6 and SSP5-8.5 scenarios, respectively, whereas farmland exhibited a diminishing trend.(2) Wetlands were primarily concentrated in the central and eastern MYRB, with counties in the southwest exhibiting superior ecological-environmental quality from 2001 to 2020. Notably,wetland coverage revealed significantly high level, significant changes, frequent but relatively minor changes under the SSP1-2.6, SSP2-4.5, and SSP 5-8.5 scenarios, respectively.(3)Regions with lower habitat quality were primarily concentrated in urbanized areas characterized by frequent human activities, indicating a clear degradation in habitat quality across different scenarios. In conclusion, we established a foundational framework for future investigations into the eco-hydrological processes and ecosystem quality of watersheds.

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Naive Bayes for value difference metric

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Frontiers of Computer Science 2014年第2期8卷 255-264页

作者： Chaoqun LI Liangxiao JIANG Hongwei LI department of mathematics China University of Geosciences Wuhan 430074 China department of Computer Science China University of Geosciences Wuhan 430074 China

The value difference metric （VDM） is one of the best-known and widely used distance functions for nominal attributes. This work applies the instance weighting technique to improve VDM. An instance weighted value difference met- ric （IWVDM） is proposed here. Different from prior work, IWVDM uses naive Bayes （NB） to find weights for train- ing instances. Because early work has shown that there is a close relationship between VDM and NB, some work on NB can be applied to VDM. The weight of a training instance x, that belongs to the class c, is assigned according to the dif- ference between the estimated conditional probability P（c／x） by NB and the true conditional probability P（c／x）, and the weight is adjusted iteratively. Compared with previous work, IWVDM has the advantage of reducing the time complex- ity of the process of finding weights, and simultaneously im- proving the performance of VDM. Experimental results on 36 UCI datasets validate the effectiveness of IWVDM.

关键词： value difference metric instance weighting,naive Bayes distance-based learning algorithms

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Spatiotemporal evolution of Ediacaran-Cambrian(ca. 551–523 Ma)sponges in South China and their simulated contributions to marine oxygenation

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Science China Earth Sciences 2025年

作者： Yan YE Lei ZHANG Can CHEN Shan CHANG Yuhao YI Qinglai FENG State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(Wuhan) School of Earth Science China University of Geosciences(Wuhan) department of Geology Lund University Institute of Sedimentary Geology Chengdu University of Technology Key Laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology Second Geological Brigade of Hubei Geological Bureau College of Urban and Environmental Sciences Hubei Normal University Exploration and Development Research Institute SINOPEC Jianghan Oilfield Company

The origin and evolution of sponges have attracted interest, not only because they are among the most basal metazoans, but also because they act as important ecological engineers in the ocean. Previous research suggested that sponge groups diversified quickly during the Cambrian Series 2, while Terreneuvian sponge fossils are conspicuously rare and poorly substantiated. Yet, an increasing number of sponge spicules have been reported from the Ediacaran-Cambrian(E-C, ca.551–523 Ma) transitional carbonates/cherts worldwide, particularly in South China, which calls for updated discussions. Ocean oxygenation has been widely proposed to play a critical role in organismal evolution, but its relationship with sponges is unclear and falls into a “chicken-egg” dilemma. In this study, we summarize reported sponge spicule distributions from five E-C sections in South China to investigate the early evolutionary pattern of siliceous sponges. According to current stratigraphic correlation,monaxons first appear in the late Ediacaran in the intrashelf basin-slope area, and then potentially expand to the continental shelf and deep basin in the lower Cambrian. In these sections, the abundance, size, and diversity of monaxons increase upwards,followed by the appearance of diaxons, triaxons and then polyactines. Despite the uncertain affinity of the sponge fossils, it is possible that siliceous hexactinellids evolved later than siliceous demosponges, given that the earliest spicule assemblages are exclusively composed of monaxons, which commonly form bundles comparable to modern demosponges. New geochemical data from the Sifangjing section, Guizhou Province and the Yanziqiao section, Hunan Province, South China show that the appearance of sponges usually corresponds to anoxic environment. In addition, we applied the recently proposed Biological Pump, Oxygen and Phosphorus(BPOP) model to trace the evolution of oceanic oxygen concentrations with the radiation of sponges. The results indic

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R^4 corrections to holographic Schwinger effect

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Chinese Physics C 2018年第12期42卷 78-85页

作者：李飞张自强陈刚 Physical department School of Mathematics and Physics China University of GeosciencesWuhan

We consider R^4 corrections to the holographic Schwinger effect in an AdS black hole background and a confining D3-brane background. The potential between a test particle pair are performed for both backgrounds. We find there is no potential barrier ill the critical electric field, which means that the system becomes catastrophically unstable. It is shown that for both backgrounds, increasing the inverse ＇t Hooft coupling parameter 1/λ enhances the Schwinger effect. We also discuss the possible relation between the Schwinger effect and the viscosity-entropy ratio η/s in strong coupling.

关键词： holographic Schwinger effect AdS/CFT potential analysis

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Existence of periodic orbits and shift-invariant curve sequences near multiple homoclinics

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Applied mathematics(A Journal of Chinese Universities) 2014年第1期29卷 108-118页

作者： XU Yan-cong GENG Feng-jie department of mathematics Hangzhou Normal University School of Science China University of Geosciences

In this paper, the complicated dynamics is studied near a double homoclinic loops with bellows configuration for general systems. For the non-twisted multiple homoclinics, the existence of periodic orbit with the specified route and the existence of shift-invariant curve sequences defined on the cross sections of multiple homoclinics corresponding to any specified one-side infinite sequences are given. In addition, the existence regions are also located.

关键词： Bifurcations Homoclinic bellows Periodic orbit Invariant-curve sequences

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IMPROVED ENTROPY-ULTRA-BEE SCHEME FOR THE EULER SYSTEM OF GAS DYNAMICS

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Journal of Computational mathematics 2017年第2期35卷 121-151页

作者： Rongsan Chen Dekang Mao School of mathematics and Physics China University of Geosciences Wuhan China department of mathematics Shanghai University Shanghai China

The Entropy-Ultra-Bee scheme was developed for the linear advection equation and extended to the Euler system of gas dynamics in [13]. It was expected that the technology be applied only to the second characteristic field of the system and the computation in the other two nonlinear fields be implemented by the Godunov scheme. However, the numerical experiments in [13] showed that the scheme, though having improved the wave resolution in the second field, produced numerical oscillations in the other two nonlinear fields. Sophisticated entropy increaser was designed to suppress the spurious oscillations by increasing the entropy when there are waves in the two nonlinear fields presented. However, the scheme is then not efficient neither robust with problem-related parameters. The purpose of this paper is to fix this problem. To this end, we first study a 3 × 3 linear system and apply the technology precisely to its second characteristic field while maintaining the computation in the other two fields be implemented by the Godunov scheme. We then follow the discussion for the linear system to apply the Entropy-Ultra-Bee technology to the second characteristic field of the Euler system in a linearlized field-by- field fashion to develop a modified Entropy-Ultra-Bee scheme for the system. Meanwhile a remark is given to explain the problem of the previous Entropy-Ultra-Bee scheme in [13]. A reference solution is constructed for computing the numerical entropy, which maintains the feature of the density and flats the velocity and pressure to constants. The numerical entropy is then computed as the entropy cell-average of the reference solution. Several limitations are adopted in the construction of the reference solution to further stabilize the scheme. Designed in such a way, the modified Entropy-Ultra-Bee scheme has a unified form with no problem-related parameters. Numerical experiments show that all the spurious oscillations in smooth regions are gone and the results ar

关键词： Entropy-Ultra-Bee scheme Step-reconstruction Characteristic field Referencesolution.

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ASYMPTOTIC BEHAVIOR FOR RANDOM WALK IN RANDOM ENVIRONMENT WITH HOLDING TIMES

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Acta Mathematica Scientia 2010年第5期30卷 1696-1708页

作者：毛明志李志民 School of mathematics and Physics China University of Geosciences department of Applied mathematics and Physics Anhui Institute of Science and Technology

In this article, we mainly discuss the asymptotic behavior for multi-dimensional continuous-time random walk in random environment with holding times. By constructing a renewal structure and using the point ＂environment viewed from the particle＂, under General Kalikow＇s Condition, we show the law of large numbers （LLN） and central limit theorem （CLT） for the escape speed of random walk.

关键词： random walk random environment central limit theorem law of large numbers renewal structure

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Asymptotics for the Tail Probability of Random Sums with a Heavy-Tailed Random Number and Extended Negatively Dependent Summands

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Chinese Annals of mathematics,Series B 2014年第1期35卷 69-78页

作者： Fengyang CHENG Na LI department of mathematics Soochow University School of geosciences China University of Petroleum(East China)

Let （X, Xk ： k ≥ 1） be a sequence of extended negatively dependent random variables with a common distribution F satisfying EX 〉 *** τ be a nonnegative integer-valued random variable, independent of {X, Xk ： k ≥ 1}. In this paper, the authors obtain the necessary and sufficient conditions for the random sums Sτ=∑n=1^τ Xn to have a consistently varying tail when the random number τ has a heavier tail than the summands, i.e.,P（X〉x）/P（τ〉x）→0 as x →∞.

关键词： Asymptotic behavior Random sums Heavy-Tailed distribution

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ON THE STRUCTURE OF THE ATTRACTORS OF HYPERBOLIC ITERATED FUNCTION SYSTEMS

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Acta Mathematicae Applicatae Sinica 1998年第2期14卷 152-156页

作者：殷庆和 department of mathematics China University of Geosciences Wuhan China

In this paper, we discuss the construction of attractors and Markov attractors of hyperboliciterated function systems. We show that when M is an irreducible GI matrix, for a huge amount(in the sense a.e. for any ergodic measure) of elements (j,,iZ,...)∈∑Mt the Markov attractor AMcan be approached by the set{TjkoTjk-1o…oTj1x;k≥m}, x∈X.

关键词： Markov attractors

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Identification of hydraulic conductivity distributions in density dependent flow fields of submarine groundwater discharge modeling using adjoint-state sensitivities

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Science China Earth Sciences 2016年第4期59卷 770-779页

作者： HU Bill X CAO YanZhao ZHAO WeiDong BAO Feng School of Water Resources and Environmental Sciences China University of Geosciences department of Geological Sciences Florida State University department of mathematics and Statistics Auburn University School of mathematics Shandong University

A mathematical optimal control method is developed to identify a hydraulic conductivity distribution in a density dependent flow field. Using a variational method, the adjoint partial differential equations are obtained for the density-dependent state equations used for the saline aquifer water flow. The adjoint equations are numerically solved in through a finite difference method. The developed method is applied to identify the hydraulic conductivity distribution through the numerical solution of an optimal control problem. To demonstrate the effectiveness of the optimal control method, three numerical experiments are conducted with artificial observation data. The results indicate that the developed method has the potential to accurately identify the hydraulic conductivity distribution in a saline water aquifer flow system.

关键词： Variable-density flow Hydraulic conductivity Inverse method Adjoint partial differential equation Submarine groundwater discharge

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