From the perspective of eco-functions of street trees,this study focuses on the conflicts between street trees and shops along the commercial streets,by taking Shanghai City for an example,investigates the present sit...From the perspective of eco-functions of street trees,this study focuses on the conflicts between street trees and shops along the commercial streets,by taking Shanghai City for an example,investigates the present situation of street trees in its old commercial districts,elaborates the significance of reducing functions of street trees by combining with relevant statistics,and proposes corresponding suggestions.展开更多
In this paper,we study the computative structure of computable function-a structure of computative tree,and,by analysis on it,got the most general algorithm and model for computation on computable functions.
The medical monitoring system is widely used. In the medical monitoring system, each user only possesses one piece of data logging that participates in statistical computing. Specifically in such a situation, a feasib...The medical monitoring system is widely used. In the medical monitoring system, each user only possesses one piece of data logging that participates in statistical computing. Specifically in such a situation, a feasible solution is to scatter its statistical computing workload to corresponding statistical nodes. Moreover, there are still two problems that should be resolved. One is how the server takes advantage of intermediate results obtained through statistical node aggregation to perform statistical computing. Statistical variable decomposition technique points out the direction for statistical projects. The other problem is how to design an efficient topological structure for statistical computing. In this paper, tree topology was adopted to implement data aggregation to improve aggregation efficiency. And two experiments were done for time consumption of statistical computing which focuses on encrypted data aggregation and encrypted data computing. The first experiment indicates that encrypted data aggregation efficiency of the scheme proposed in this paper is better than that of Drosatos' scheme, and the second indicates that improving computing power of the server or computational efficiency of the functional encryption scheme can shorten the computation time.展开更多
Given a system {S1,…, SN} of N contractive similarities satisfying some strong separation condition, it has an invariant Set K for the system. In this article, the authors construct some random measure μω supported...Given a system {S1,…, SN} of N contractive similarities satisfying some strong separation condition, it has an invariant Set K for the system. In this article, the authors construct some random measure μω supported on random subset Kω of K, μω having some ＂non-standard＂ multifractal structure, which contrasts the well-knoWn multifractal formalism for the invariant measure of system {S1,.., SN} may possess. The main tool is the multifractal structures of a Galton-Watson tree, which are obtained by Liu [9], Shieh-Taylor [14], and MSrters-Shieh [12].展开更多
Agriculture and farming are mainly dependent on weather especially in Malaysia as it received heavy rainfall throughout the years. An efficient crop or tree management system with a weather forecast needed for suitabl...Agriculture and farming are mainly dependent on weather especially in Malaysia as it received heavy rainfall throughout the years. An efficient crop or tree management system with a weather forecast needed for suitable planning of farming operation. Radial Basis Function Neural Network (RBFNN) algorithm was used in this study to predict rainfall and the main focus of this study is to analyze the factor that affect</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the performance of neural model. This study found that the model works better the more hidden nodes and the optimum learning rate is 0.01 with the RMSE 49% and the percentage accuracy is 57%. Besides that, it is found that the meteorology data also affect the model performance. Future research can be conducted to improve the rainfall forecast of this study and improv</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">e</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the tree management system.展开更多
【目的】探讨梵净山典型优势树种根系土壤细菌群落结构、多样性、生态系统功能及其不同树种间差异的环境驱动因子。【方法】以梵净山世界自然遗产地的丝栗栲、西南米槠、厚皮栲、长柄水青冈、云山青冈和亮叶水青冈6种优势树种为研究对象...【目的】探讨梵净山典型优势树种根系土壤细菌群落结构、多样性、生态系统功能及其不同树种间差异的环境驱动因子。【方法】以梵净山世界自然遗产地的丝栗栲、西南米槠、厚皮栲、长柄水青冈、云山青冈和亮叶水青冈6种优势树种为研究对象,通过高通量测序技术分析根系土壤细菌群落组成及其在树种间的多样性差异,并应用PICRUSt(phylogenetic investigation of communities by reconstruction of unobserved states)对功能基因进行预测,基于冗余分析或相关性分析揭示土壤细菌群落、功能基因及环境因子(气候因素和土壤化学性质)间的相互关系。【结果】土壤化学性质因树种不同而存在一定差异,梵净山6种优势树种根系土壤碱解氮(AN)、有效磷(AP)和速效钾(AK)含量分别为4.09~12.98,5.64~9.91和29.38~68.33 mg/kg;全氮(TN)、全磷(TP)和全碳(TC)含量分别为1.85~3.41,0.29~0.50和33.01~85.77 g/kg;pH和C/N分别为4.45~4.82和17.19~27.58。高通量测序结果表明,从72份土壤样品中共鉴定出851个属的细菌,分属38个门、99个纲、238个目、394个科。在不同树种间,细菌群落组成存在一定差异,其中酸杆菌门、变形菌门和放线菌门是根系土壤细菌的主要优势门类,三者相对丰度之和的均值为88.27%。多样性分析表明,虽然不同树种根系土壤中的细菌群落在丰富度和多样性上表现出很高的相似性,但也存在一定差异,其中厚皮栲根系土壤的Chao1指数最高,为5284.8;亮叶水青冈的Shannon指数最高,为9.1;而长柄水青冈的Chao1指数和Shannon指数均为最低,分别为4469.8和8.5。PICRUSt功能预测表明,不同树种根系土壤细菌主要参与5类一级代谢通路及其下属的33个子功能代谢通路,其中厚皮栲和长柄水青冈的KEGG功能基因相对丰度明显高于其他树种。冗余分析显示,海拔(Alt)和土壤AN含量是驱动土壤细菌群落结构变化的关键影响因素。相关性分析表明,细菌多样性指数与年平均温度(MAT)、年均大气湿度(AAH)呈显著负相关,而与土壤全碳(TC)呈显著正相关;KEGG功能基因相对丰度与环境因子的相关性较弱,而与细菌门水平的相对丰度存在较强相关性。【结论】梵净山6种优势树种根系土壤的化学性质、细菌群落组成、多样性及KEGG功能基因相对丰度存在一定差异。Alt和土壤AN含量是不同树种根系土壤细菌群落结构产生差异的关键环境驱动因子,而KEGG功能基因相对丰度主要与细菌群落结构变化相关。展开更多
Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for t...Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.展开更多
The Oak Ridge National Laboratory (ORNL) is the largest and most diverse energy, research, and development institution within the Department of Energy (DOE) system in the United States. As such, the site endures const...The Oak Ridge National Laboratory (ORNL) is the largest and most diverse energy, research, and development institution within the Department of Energy (DOE) system in the United States. As such, the site endures constant land development that creates rigorous growing conditions for urban vegetation. Natural resource managers at ORNL recognize that trees are an integral component of the landscape and are interested in characterizing the urban forest and their associated ecosystem services benefits. We evaluated the urban forest structure, quantified ecosystem services and benefits, and estimated economic value of resources using i-Tree Eco at ORNL. While this assessment captured over 1100 landscape trees, the ORNL Natural Resources Management for landscape vegetation can be expanded to include unmanaged landscapes, e.g. riparian areas, greenspace, and other vegetative attributes to increase ecosystem services benefits. Assigning a monetary value to urban forest benefits help to inform decisions about urban forest management, ideally on cost-benefit analysis.展开更多
文摘From the perspective of eco-functions of street trees,this study focuses on the conflicts between street trees and shops along the commercial streets,by taking Shanghai City for an example,investigates the present situation of street trees in its old commercial districts,elaborates the significance of reducing functions of street trees by combining with relevant statistics,and proposes corresponding suggestions.
基金supported by National Natural Science Foundation of China.
文摘In this paper,we study the computative structure of computable function-a structure of computative tree,and,by analysis on it,got the most general algorithm and model for computation on computable functions.
基金Supported by the National Natural Science Foundation of China(91112003)
文摘The medical monitoring system is widely used. In the medical monitoring system, each user only possesses one piece of data logging that participates in statistical computing. Specifically in such a situation, a feasible solution is to scatter its statistical computing workload to corresponding statistical nodes. Moreover, there are still two problems that should be resolved. One is how the server takes advantage of intermediate results obtained through statistical node aggregation to perform statistical computing. Statistical variable decomposition technique points out the direction for statistical projects. The other problem is how to design an efficient topological structure for statistical computing. In this paper, tree topology was adopted to implement data aggregation to improve aggregation efficiency. And two experiments were done for time consumption of statistical computing which focuses on encrypted data aggregation and encrypted data computing. The first experiment indicates that encrypted data aggregation efficiency of the scheme proposed in this paper is better than that of Drosatos' scheme, and the second indicates that improving computing power of the server or computational efficiency of the functional encryption scheme can shorten the computation time.
基金Both authors are supported by a grant NSC 2002/3-2115-M-002-017.
文摘Given a system {S1,…, SN} of N contractive similarities satisfying some strong separation condition, it has an invariant Set K for the system. In this article, the authors construct some random measure μω supported on random subset Kω of K, μω having some ＂non-standard＂ multifractal structure, which contrasts the well-knoWn multifractal formalism for the invariant measure of system {S1,.., SN} may possess. The main tool is the multifractal structures of a Galton-Watson tree, which are obtained by Liu [9], Shieh-Taylor [14], and MSrters-Shieh [12].
文摘Agriculture and farming are mainly dependent on weather especially in Malaysia as it received heavy rainfall throughout the years. An efficient crop or tree management system with a weather forecast needed for suitable planning of farming operation. Radial Basis Function Neural Network (RBFNN) algorithm was used in this study to predict rainfall and the main focus of this study is to analyze the factor that affect</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the performance of neural model. This study found that the model works better the more hidden nodes and the optimum learning rate is 0.01 with the RMSE 49% and the percentage accuracy is 57%. Besides that, it is found that the meteorology data also affect the model performance. Future research can be conducted to improve the rainfall forecast of this study and improv</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">e</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the tree management system.
文摘【目的】探讨梵净山典型优势树种根系土壤细菌群落结构、多样性、生态系统功能及其不同树种间差异的环境驱动因子。【方法】以梵净山世界自然遗产地的丝栗栲、西南米槠、厚皮栲、长柄水青冈、云山青冈和亮叶水青冈6种优势树种为研究对象,通过高通量测序技术分析根系土壤细菌群落组成及其在树种间的多样性差异,并应用PICRUSt(phylogenetic investigation of communities by reconstruction of unobserved states)对功能基因进行预测,基于冗余分析或相关性分析揭示土壤细菌群落、功能基因及环境因子(气候因素和土壤化学性质)间的相互关系。【结果】土壤化学性质因树种不同而存在一定差异,梵净山6种优势树种根系土壤碱解氮(AN)、有效磷(AP)和速效钾(AK)含量分别为4.09~12.98,5.64~9.91和29.38~68.33 mg/kg;全氮(TN)、全磷(TP)和全碳(TC)含量分别为1.85~3.41,0.29~0.50和33.01~85.77 g/kg;pH和C/N分别为4.45~4.82和17.19~27.58。高通量测序结果表明,从72份土壤样品中共鉴定出851个属的细菌,分属38个门、99个纲、238个目、394个科。在不同树种间,细菌群落组成存在一定差异,其中酸杆菌门、变形菌门和放线菌门是根系土壤细菌的主要优势门类,三者相对丰度之和的均值为88.27%。多样性分析表明,虽然不同树种根系土壤中的细菌群落在丰富度和多样性上表现出很高的相似性,但也存在一定差异,其中厚皮栲根系土壤的Chao1指数最高,为5284.8;亮叶水青冈的Shannon指数最高,为9.1;而长柄水青冈的Chao1指数和Shannon指数均为最低,分别为4469.8和8.5。PICRUSt功能预测表明,不同树种根系土壤细菌主要参与5类一级代谢通路及其下属的33个子功能代谢通路,其中厚皮栲和长柄水青冈的KEGG功能基因相对丰度明显高于其他树种。冗余分析显示,海拔(Alt)和土壤AN含量是驱动土壤细菌群落结构变化的关键影响因素。相关性分析表明,细菌多样性指数与年平均温度(MAT)、年均大气湿度(AAH)呈显著负相关,而与土壤全碳(TC)呈显著正相关;KEGG功能基因相对丰度与环境因子的相关性较弱,而与细菌门水平的相对丰度存在较强相关性。【结论】梵净山6种优势树种根系土壤的化学性质、细菌群落组成、多样性及KEGG功能基因相对丰度存在一定差异。Alt和土壤AN含量是不同树种根系土壤细菌群落结构产生差异的关键环境驱动因子,而KEGG功能基因相对丰度主要与细菌群落结构变化相关。
基金National Basic Research Program of China,No.2015CB953603National Natural Science Foundation of China,No.41671339State Key Laboratory of Earth Surface Processes and Resource Ecology,No.2017-FX-01(1)
文摘Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment.
文摘The Oak Ridge National Laboratory (ORNL) is the largest and most diverse energy, research, and development institution within the Department of Energy (DOE) system in the United States. As such, the site endures constant land development that creates rigorous growing conditions for urban vegetation. Natural resource managers at ORNL recognize that trees are an integral component of the landscape and are interested in characterizing the urban forest and their associated ecosystem services benefits. We evaluated the urban forest structure, quantified ecosystem services and benefits, and estimated economic value of resources using i-Tree Eco at ORNL. While this assessment captured over 1100 landscape trees, the ORNL Natural Resources Management for landscape vegetation can be expanded to include unmanaged landscapes, e.g. riparian areas, greenspace, and other vegetative attributes to increase ecosystem services benefits. Assigning a monetary value to urban forest benefits help to inform decisions about urban forest management, ideally on cost-benefit analysis.
