In order to research the population distribution pattern of endangered species Toona ciliata Roem., the sampling quadrats of 5 mx5 m and 3 m×3 m in size, accurate to 1 mxl m, were established in 2 newly-found onl...In order to research the population distribution pattern of endangered species Toona ciliata Roem., the sampling quadrats of 5 mx5 m and 3 m×3 m in size, accurate to 1 mxl m, were established in 2 newly-found only existing T. cili- ata Roem. communities （T1 and T2） with contiguous grid quadrate method, in the Nanhe River valley, Gucheng County. By X2 test, t-test of distribution coefficient Cx method, and F test of Morisita pattern index Iδ whether the distribution patterns of the T. ciliata Roem. populations conformed to Poisson distribution were checked. The results indicated that, population T1 was in Poisson distribution under 5 m×5 m and 3 m×3 m in size by Cx and 16 methods, but in clumped distribution pattern un- der 5 m×5 m in size by the Chi-square test; however, the population was in Pois- son distribution under the dimension of 3 m×3 m. Population T2 under human dis- turbance had higher population density, indicating clumped distribution under 3 above-mentioned tests. If Chi-square test is satisfied, a distribution pattern is in Poisson distribution, and size and quantity of sampling quadrats should be given pri- ority to; and if df is greater, both theoretical values and observed values tend to- wards normal distribution more probably, and the test of distribution pattern, there- fore will be more dependable.展开更多
In this study,the thermodynamic behaviors of the intrinsic frequency and buckling temperature of rectangular plates of functionally graded materials(FGMs)are explored based on the modified couple stress theory(MCST)an...In this study,the thermodynamic behaviors of the intrinsic frequency and buckling temperature of rectangular plates of functionally graded materials(FGMs)are explored based on the modified couple stress theory(MCST)and the novel dual powerlaw scale distribution theory.The effects of linear,homogeneous,and non-homogeneous temperature fields on the frequency and buckling temperature of FGM microplates are evaluated in detail.The results show that the porosity greatly affects the mechanical properties of FGM plates,reducing their frequency and flexural temperature compared with non-porous plates.Different temperature profiles alter plate frequencies and buckling temperatures.The presence and pattern of scale effect parameters are also shown to be crucial for the mechanical response of FGM plates.The present research aims to provide precise guidelines for the micro-electro-mechanical system(MEMS)fabrication by elucidating the complex interplay between thermal,material,and structural factors that affect the performance of FGM plates in advanced applications.展开更多
Joint location and scale models of the skew-normal distribution provide useful ex- tension for joint mean and variance models of the normal distribution when the data set under consideration involves asymmetric outcom...Joint location and scale models of the skew-normal distribution provide useful ex- tension for joint mean and variance models of the normal distribution when the data set under consideration involves asymmetric outcomes. This paper focuses on the maximum likelihood estimation of joint location and scale models of the skew-normal distribution. The proposed procedure can simultaneously estimate parameters in the location model and the scale model. Simulation studies and a real example are used to illustrate the proposed methodologies.展开更多
In this paper, we propose a robust mixture regression model based on the skew scale mixtures of normal distributions (RMR-SSMN) which can accommodate asymmetric, heavy-tailed and contaminated data better. For the vari...In this paper, we propose a robust mixture regression model based on the skew scale mixtures of normal distributions (RMR-SSMN) which can accommodate asymmetric, heavy-tailed and contaminated data better. For the variable selection problem, the penalized likelihood approach with a new combined penalty function which balances the SCAD and l<sub>2</sub> penalty is proposed. The adjusted EM algorithm is presented to get parameter estimates of RMR-SSMN models at a faster convergence rate. As simulations show, our mixture models are more robust than general FMR models and the new combined penalty function outperforms SCAD for variable selection. Finally, the proposed methodology and algorithm are applied to a real data set and achieve reasonable results.展开更多
The distribution pattern of Isoetes sinensis populations was investigated in relation to its biological characteristics such as age structure and regeneration mode, and the microenvironment. Contagious distribution pa...The distribution pattern of Isoetes sinensis populations was investigated in relation to its biological characteristics such as age structure and regeneration mode, and the microenvironment. Contagious distribution pattern was found in populations of all sizes. Under the same climatic and site conditions, the heterogeneity of mieroenvironment resulting from the different depths of water and soil erosion significantly affecred the type and scale of distribution patterns of Isoetes sinensis populations. Even at the same site, the center and the edges of the water body had different effects on the distribution pattern of the plants. As one of the co-dominants, the distribution of Isoetes sinensis in communities was affected by other dominant species, especially by the evergreen grass species. Water is the major factor determining the distribution pattern of lsoetes sinensis in various communities. The pattern of contagious distribution was observed in different size of populations of I.sinensis, however the Lloyd indices obtained for the populations of various sizes differed significantly.展开更多
With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in th...With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in the backward rapidity regions. Using this scaling distribution, we get the theoretical psedorapidity asymmetry which is basically in agreement with STAR data in the regions of 0≤｜η｜≤0.5 and 0.5 ≤｜η｜≤1. No theoretical models are used in any part of this phenomenological analysis.展开更多
A new family of univariate exponential slash distribution is introduced, which is based on elliptical distributions and defined by means of a stochastic representation as the scale mixture of an elliptically distribut...A new family of univariate exponential slash distribution is introduced, which is based on elliptical distributions and defined by means of a stochastic representation as the scale mixture of an elliptically distributed random variable with respect to the power of an exponential random variable. The same idea is extended to the multivariate case. General properties of the resulting families, including their moments and kurtosis coefficient, are stud- ied. And inferences based on methods of moment and maximum likelihood are discussed. A real data is presented to show this family is flexible and fits much better than other related families.展开更多
Many real-world systems can be modeled by weighted small-world networks with high clustering coefficients. Recent studies for rigorously analyzing the weighted spectral distribution（W SD） have focused on unweighted ...Many real-world systems can be modeled by weighted small-world networks with high clustering coefficients. Recent studies for rigorously analyzing the weighted spectral distribution（W SD） have focused on unweighted networks with low clustering coefficients. In this paper, we rigorously analyze the W SD in a deterministic weighted scale-free small-world network model and find that the W SD grows sublinearly with increasing network order（i.e., the number of nodes） and provides a sensitive discrimination for each input of this model. This study demonstrates that the scaling feature of the W SD exists in the weighted network model which has high and order-independent clustering coefficients and reasonable power-law exponents.展开更多
在考虑不确定性的基础上,提出了包含燃气轮机、储能、电池充放电设备、风电、光伏的新型电池充换电站多时间尺度能量管理策略。首先基于荷电状态(state of charge,SOC)区间对电池进行了建模,并将其充电和放电优先级嵌入到优化中。然后,...在考虑不确定性的基础上,提出了包含燃气轮机、储能、电池充放电设备、风电、光伏的新型电池充换电站多时间尺度能量管理策略。首先基于荷电状态(state of charge,SOC)区间对电池进行了建模,并将其充电和放电优先级嵌入到优化中。然后,分别建立了日前分布鲁棒优化、日内滚动优化和日内实时优化模型:日前优化在考虑风电、光伏和负荷的预测误差的基础上,以最小期望总成本优化燃气轮机的启停状态、电池充放电设备的功率和储能的能量参考值,并基于线性决策规则和对偶理论转化为混合整数规划进行求解;日内优化根据日前优化的参考值和最新的预测信息,以总运行成本最低重新优化燃气轮机和储能的功率;实时优化根据日内滚动优化的参考值和实时的预测信息,以总运行成本最低再次重新优化燃气轮机和储能的功率,并将第一个控制时段的指令下发。最后,算例结果表明所提出的多时间尺度能量管理策略能有效地兼顾新型电池充换电站的运行经济性和鲁棒性。展开更多
Zeolites,as a class of porous inorganic materials,are extensively employed across a range of industrial applications,including catalysis[1],and adsorption separation[2],owing to their exceptional thermal stability,hig...Zeolites,as a class of porous inorganic materials,are extensively employed across a range of industrial applications,including catalysis[1],and adsorption separation[2],owing to their exceptional thermal stability,highly ordered pore structures,and tunable acidic properties.These characteristics enable zeolites to perform with remarkable efficiency and versatility in various processes.However,in the commonly employed aluminosilicate zeolites,Al atoms,acting as the active centers of acidity.展开更多
Mangrove management in China is converting from emphasis on occupied area to intrinsical quality.Mangrove species have varied ecological values,e.g.,those having well-developed prop roots are more beneficial for coast...Mangrove management in China is converting from emphasis on occupied area to intrinsical quality.Mangrove species have varied ecological values,e.g.,those having well-developed prop roots are more beneficial for coastal stabilization.The detailed distribution of mangrove species on a national scale remains a challenge,impeding species-specific applications in the ecology and management of mangroves,as well as evaluations of related Sustainable Development Goals.Although local-scale studies have explored various data sources,the variability of plant phenology is the key factor preventing their generalization from local areas to large latitudinal spans(e.g.,the coast of China).The separability time period,defined by a separability metric for each scene of the image time series,provides a potential way to tackle the aforementioned problem.We conducted a case study on mapping Kandelia obovata in China based on Sentinel-2 time-series imagery,as it is a representative native mangrove species with the largest latitudinal span and tolerance to low temperatures.The proposed approach considered the separability between K.obovata and its typical co-occurring mangrove species,as well as that between K.obovata and salt marshes.The overall accuracy of the generated K.obovata map in China for 2020 reached 88.5%based on independently collected samples.The proposed approach is transferable to diverse mangrove species that inhabit a vast latitudinal span.The implications for sustainable mangrove management were discussed to reveal the benefits to precise management of mangroves,accurate biomass and carbon estimations accounting for species differences,and effective evaluation of mangrove ecosystem services.展开更多
基金Supported by Public Welfare Research Project of Science and Technology Agency of Hubei Province(402012DBA40001)~~
文摘In order to research the population distribution pattern of endangered species Toona ciliata Roem., the sampling quadrats of 5 mx5 m and 3 m×3 m in size, accurate to 1 mxl m, were established in 2 newly-found only existing T. cili- ata Roem. communities （T1 and T2） with contiguous grid quadrate method, in the Nanhe River valley, Gucheng County. By X2 test, t-test of distribution coefficient Cx method, and F test of Morisita pattern index Iδ whether the distribution patterns of the T. ciliata Roem. populations conformed to Poisson distribution were checked. The results indicated that, population T1 was in Poisson distribution under 5 m×5 m and 3 m×3 m in size by Cx and 16 methods, but in clumped distribution pattern un- der 5 m×5 m in size by the Chi-square test; however, the population was in Pois- son distribution under the dimension of 3 m×3 m. Population T2 under human dis- turbance had higher population density, indicating clumped distribution under 3 above-mentioned tests. If Chi-square test is satisfied, a distribution pattern is in Poisson distribution, and size and quantity of sampling quadrats should be given pri- ority to; and if df is greater, both theoretical values and observed values tend to- wards normal distribution more probably, and the test of distribution pattern, there- fore will be more dependable.
基金Project supported by the National Key Research and Development Program of China(No.2022YFB3207100)Hubei Provincial Strategic Scientist Training Plan(No.2022EJD009)the Fundamental Research Funds for the Central Universities of China(No.2042023kf1041)。
文摘In this study,the thermodynamic behaviors of the intrinsic frequency and buckling temperature of rectangular plates of functionally graded materials(FGMs)are explored based on the modified couple stress theory(MCST)and the novel dual powerlaw scale distribution theory.The effects of linear,homogeneous,and non-homogeneous temperature fields on the frequency and buckling temperature of FGM microplates are evaluated in detail.The results show that the porosity greatly affects the mechanical properties of FGM plates,reducing their frequency and flexural temperature compared with non-porous plates.Different temperature profiles alter plate frequencies and buckling temperatures.The presence and pattern of scale effect parameters are also shown to be crucial for the mechanical response of FGM plates.The present research aims to provide precise guidelines for the micro-electro-mechanical system(MEMS)fabrication by elucidating the complex interplay between thermal,material,and structural factors that affect the performance of FGM plates in advanced applications.
基金Supported by the National Natural Science Foundation of China(11261025,11201412)the Natural Science Foundation of Yunnan Province(2011FB016)the Program for Middle-aged Backbone Teacher,Yunnan University
文摘Joint location and scale models of the skew-normal distribution provide useful ex- tension for joint mean and variance models of the normal distribution when the data set under consideration involves asymmetric outcomes. This paper focuses on the maximum likelihood estimation of joint location and scale models of the skew-normal distribution. The proposed procedure can simultaneously estimate parameters in the location model and the scale model. Simulation studies and a real example are used to illustrate the proposed methodologies.
文摘In this paper, we propose a robust mixture regression model based on the skew scale mixtures of normal distributions (RMR-SSMN) which can accommodate asymmetric, heavy-tailed and contaminated data better. For the variable selection problem, the penalized likelihood approach with a new combined penalty function which balances the SCAD and l<sub>2</sub> penalty is proposed. The adjusted EM algorithm is presented to get parameter estimates of RMR-SSMN models at a faster convergence rate. As simulations show, our mixture models are more robust than general FMR models and the new combined penalty function outperforms SCAD for variable selection. Finally, the proposed methodology and algorithm are applied to a real data set and achieve reasonable results.
基金Supported by the State Key Basic Research and DevelopmentProgram(G2000046805) .
文摘The distribution pattern of Isoetes sinensis populations was investigated in relation to its biological characteristics such as age structure and regeneration mode, and the microenvironment. Contagious distribution pattern was found in populations of all sizes. Under the same climatic and site conditions, the heterogeneity of mieroenvironment resulting from the different depths of water and soil erosion significantly affecred the type and scale of distribution patterns of Isoetes sinensis populations. Even at the same site, the center and the edges of the water body had different effects on the distribution pattern of the plants. As one of the co-dominants, the distribution of Isoetes sinensis in communities was affected by other dominant species, especially by the evergreen grass species. Water is the major factor determining the distribution pattern of lsoetes sinensis in various communities. The pattern of contagious distribution was observed in different size of populations of I.sinensis, however the Lloyd indices obtained for the populations of various sizes differed significantly.
基金National Natural Science Foundation of China under Grant No.10777577
文摘With the experimental data from STAR program on the centrality dependence of the PT spectra of charged hadron produced in d＋Au collisions at √^8NN=200 GeV, we show that there also exists a scaling distribution in the backward rapidity regions. Using this scaling distribution, we get the theoretical psedorapidity asymmetry which is basically in agreement with STAR data in the regions of 0≤｜η｜≤0.5 and 0.5 ≤｜η｜≤1. No theoretical models are used in any part of this phenomenological analysis.
基金Supported by the National Natural Science Foundation of China(Grant No.61304155)Beijing Municipal Party Committee Organization Department Talents Project(Grant No.2012D005003000005)Graduate Department of BTBU Comprehensive Reform Project to Promote Talent Cultivation(Grant No.19005428069)
文摘A new family of univariate exponential slash distribution is introduced, which is based on elliptical distributions and defined by means of a stochastic representation as the scale mixture of an elliptically distributed random variable with respect to the power of an exponential random variable. The same idea is extended to the multivariate case. General properties of the resulting families, including their moments and kurtosis coefficient, are stud- ied. And inferences based on methods of moment and maximum likelihood are discussed. A real data is presented to show this family is flexible and fits much better than other related families.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61402485,61573262,and 61303061)
文摘Many real-world systems can be modeled by weighted small-world networks with high clustering coefficients. Recent studies for rigorously analyzing the weighted spectral distribution（W SD） have focused on unweighted networks with low clustering coefficients. In this paper, we rigorously analyze the W SD in a deterministic weighted scale-free small-world network model and find that the W SD grows sublinearly with increasing network order（i.e., the number of nodes） and provides a sensitive discrimination for each input of this model. This study demonstrates that the scaling feature of the W SD exists in the weighted network model which has high and order-independent clustering coefficients and reasonable power-law exponents.
文摘在考虑不确定性的基础上,提出了包含燃气轮机、储能、电池充放电设备、风电、光伏的新型电池充换电站多时间尺度能量管理策略。首先基于荷电状态(state of charge,SOC)区间对电池进行了建模,并将其充电和放电优先级嵌入到优化中。然后,分别建立了日前分布鲁棒优化、日内滚动优化和日内实时优化模型:日前优化在考虑风电、光伏和负荷的预测误差的基础上,以最小期望总成本优化燃气轮机的启停状态、电池充放电设备的功率和储能的能量参考值,并基于线性决策规则和对偶理论转化为混合整数规划进行求解;日内优化根据日前优化的参考值和最新的预测信息,以总运行成本最低重新优化燃气轮机和储能的功率;实时优化根据日内滚动优化的参考值和实时的预测信息,以总运行成本最低再次重新优化燃气轮机和储能的功率,并将第一个控制时段的指令下发。最后,算例结果表明所提出的多时间尺度能量管理策略能有效地兼顾新型电池充换电站的运行经济性和鲁棒性。
文摘Zeolites,as a class of porous inorganic materials,are extensively employed across a range of industrial applications,including catalysis[1],and adsorption separation[2],owing to their exceptional thermal stability,highly ordered pore structures,and tunable acidic properties.These characteristics enable zeolites to perform with remarkable efficiency and versatility in various processes.However,in the commonly employed aluminosilicate zeolites,Al atoms,acting as the active centers of acidity.
基金supported by the National Key R&D Program of China(2022YFF1302000)the Open Research Program of the International Research Center of Big Data for Sustainable Development Goals(CBAS2022ORP06)+3 种基金the National Natural Science Foundation of China(42201422)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021227)the National Earth System Science Data Center(www.geodata.cn)We also thank the Science and Technology Basic Resources Investigation Program of China(2017FY100700)for providing field sample plots with mangrove species composition.
文摘Mangrove management in China is converting from emphasis on occupied area to intrinsical quality.Mangrove species have varied ecological values,e.g.,those having well-developed prop roots are more beneficial for coastal stabilization.The detailed distribution of mangrove species on a national scale remains a challenge,impeding species-specific applications in the ecology and management of mangroves,as well as evaluations of related Sustainable Development Goals.Although local-scale studies have explored various data sources,the variability of plant phenology is the key factor preventing their generalization from local areas to large latitudinal spans(e.g.,the coast of China).The separability time period,defined by a separability metric for each scene of the image time series,provides a potential way to tackle the aforementioned problem.We conducted a case study on mapping Kandelia obovata in China based on Sentinel-2 time-series imagery,as it is a representative native mangrove species with the largest latitudinal span and tolerance to low temperatures.The proposed approach considered the separability between K.obovata and its typical co-occurring mangrove species,as well as that between K.obovata and salt marshes.The overall accuracy of the generated K.obovata map in China for 2020 reached 88.5%based on independently collected samples.The proposed approach is transferable to diverse mangrove species that inhabit a vast latitudinal span.The implications for sustainable mangrove management were discussed to reveal the benefits to precise management of mangroves,accurate biomass and carbon estimations accounting for species differences,and effective evaluation of mangrove ecosystem services.
