检索结果-南通市图书馆

Geographical Agglomeration of Chinese Manufacturing Industries

中国人口·资源与环境：英文版 2007年第2期5卷 3-11页

作者： Zhang Hua 1, 2, Zheng Wei3.1. Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china 2. Graduate school of the Chinese Academy of Sciences, beijing 10003., china 3. school of geography, beijing normal university, beijing 100875, china Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Graduate school of the Chinese Academy of Sciences Beijing 100039 China school of geography Beijing Normal University Beijing 100875 China

Based on the plant level data from the First National Census of Basic Units, the Second National Census of Basic Units, and the First National Economic Census of china, this paper ex- amines the geographical agglomeration of Chinese manufacturing industries at a more disaggregated level both by industrial classi-fication and spatial unit analysis. Applying the agglomeration index proposed by Maurel and Sedillot, studies show that the most agglomerated industries are resource-intensive, and capital and technology intensive while industries demanding localized inputs or serving localized markets or favored by local governments are fairly dispersed. The more disaggregated industries are more spa- tially agglomerated. At the finer spatial scale, industries are more dispersed. Results indicate that within-county spillovers are stronger than nearby-county spillovers, and within-prefecture spillovers are stronger than nearby prefecture spillovers. Local- ized spillovers are still quite substantial at a range beyond that of counties. Comparing the agglomeration index of Chinese manu- facturing industries in 1996, 2001 and 2004, agglomeration seems to be a general tendency. Results also indicate that some industries have experienced remarkable changes in their levels of agglom- eration in the period 1996–2004.

关键词： industrial agglomeration manufacturing industries the MS index

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Key points on temperature change of the past 2000 years in china

引用

Progress in Natural Science:Materials International 2004年第8期 82-89页

作者： GE Quansheng 1, ZHENG Jingyun 1*, MAN Zhimin 2, FANG Xiuqi 3.1 and ZHANG Piyuan 1(1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, china 2. Institute of Chinese History geography, Fudan {3., Shanghai 20043., china 3. school of geography, beijing normal university, beijing 100875, china) Institute of Geographic Sciences and Natural Resources Research，Chinese Academy of Sciences，beijing 100101，china Institute of Chinese History geography，Fudan university，Shanghai 20043.，china school of geography，beijing {3. university，beijing 100875，china Institute of Geographic Sciences and Natural Resources Research，Chinese Academy of Sciences，beijing 100101，china

Temperature change of the past 2000 years in china is discussed based on the winter half-year temperature series of the past 2000 years in eastern china reconstructed recently, and other related studies. The main conclusions are as follows: (1) The Little Ice Age (LIA) in china began in the early of the 14th century (13.0s) and ended in the beginning of the 20th century (1910s), which was composed of four evident cold stages and three short warming stages. The cold period in the Wei, Jin and South-North dynasties (210s～560s) was the only one comparable with LIA for the past 2000 years. (2) The Medieval Warm Period (MWP) in china began in the 93.s and ended in the 13.0s, which was composed of two warm stages over 100 years and a cold stage less than 100 years. (3. The climate in the Sui and Tang dynasties should be divided into two stages: the climate in the 570s～770s was as warm as that in the 20th century; while the temperature in the 780s～920s was lower than that in the 1950s～1970s. (4) In eastern china as a whole, winter half-year temperature variation with over 1 ℃ occurred between the cold and warm stages on centennial scale, while the changing rate exceeded 1.0 ℃ per century. (5) There exists an about 13.0-year periodicity in the historical temperature change. Inferred from the periodicity, the most likely historical analogue for the warming in the 20th century is the warm stage of the Sui and Tang dynasties (570s～770s), instead of the Medieval Warm Period. (6) Although it was critically warm, the temperature of the 20th century in eastern china is still within the threshold of the variability of the last 2000 years.

关键词： eastern china past 2000 years temperature change.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Recommendation Method for Contrastive Enhancement of Neighborhood Information

引用

Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma school of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

ENERGY FLOWS IN COMPLEX ECOLOGICAL SYSTEMS:A REVIEW

引用

Journal of Systems Science & Complexity 2009年第3期22卷 345-359页

作者： Jiang ZHANG Department of Systems Science,school of Management,beijing normal {3.,beijing 100875,china. Department of Systems Science School of Management Beijing Normal University Beijing China

Energy flow drives the complex systems to *** allometric scaling as the universalenergy flow pattern has been found in different scales of ecological *** reflects the generalpower law relationship between flow and *** underlying mechanisms of energy flow patterns areexplained as the branching transportation networks which can be regarded as the result of systematicoptimization of a biological target under *** flows in the ecological system may bemodelled by the food web model and population dynamics on the *** paper reviews thelatest progress on the energy flow patterns,explanatory models for the allometric scaling and modellingapproach of flow and network evolution dynamics in ***,the possibility of generalizingthese flow patterns,modelling approaches to other complex systems is discussed.

关键词： Allometric scaling energy flow flows in complex systems food web.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Extracting impervious surfaces from multi-source satellite imagery based on unified conceptual model by decision tree algorithm

引用

Science china(Technological Sciences) 2010年第S1期53卷 68-74页

作者： QIAO Yu,LIU HuiPing,BAI Mu,WANG XiaoDong & ZHOU XiaoLuo school of geography,beijing {3. university,beijing 100875,china school of geography Beijing Normal University Beijing China

Extraction of impervious surfaces is one of the necessary processes in urban change *** paper derived a unified conceptual model (UCM) from the vegetation-impervious surface-soil (VIS) model to make the extraction more effective and *** uses the decision tree algorithm with indices of spectrum and texture,*** this model,we found both dependent and independent indices for multi-source satellite imagery according to their similarity and *** purpose of the indices is to remove the other land-use and land-cover types (e.g.,vegetation and soil) from the imagery,and delineate the impervious surfaces as the *** has the same steps conducted by decision tree *** Landsat-5 TM image (3. m) and the Satellite Probatoire d’Observation de la Terre (SPOT-4) image (20 m) from Chaoyang District (beijing) in 2007 were used in this *** results show that the overall accuracy in Landsat-5 TM image is 88%,while 86.75% in SPOT-4 *** is an appropriate method to meet the demand of urban change detection.

关键词： multi-source satellite imagery impervious surfaces extraction VIS model decision tree algorithm

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Functional central limit theorem for super α-stable processes

引用

Science china Mathematics 2004年第6期47卷 874-881页

作者： HONG WenmingDepartment of Mathematics, beijing normal university, beijing 100875, china Department of Mathematics Beijing Normal University Beijing China

A functional central limit theorem is proved for the centered occupation time process of the super α-stable processes in the finite dimensional distribution sense. For the intermediate dimensions α < d < 2α (0 < α ≤ 2), the limiting process is a Gaussian process, whose covariance is specified; for the critical dimension d= 2α and higher dimensions d < 2α, the limiting process is Brownian motion.

关键词： super α-stable processes occupation time central limit theorem evolution equation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the weak convergence of super-Brownian motion with immigration

引用

Science china Mathematics 2009年第9期52卷 1875-1886页

作者： ZHANG Mei school of Mathematical Sciences, beijing normal university, beijing 100875,{3. school of Mathematical Sciences Beijing Normal University Beijing China

We prove fluctuation limit theorems for the occupation times of super-Brownian motion with immigration. The weak convergence of the processes is established, which improves the results in references. The limiting proc... 详细信息

关键词： super-Brownian motion with immigration occupation time process central limit theorem tightness 60J80 60F05

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On asymptotics of t-type regression estimation in multiple linear model

引用

Science china Mathematics 2004年第4期47卷 628-639页

作者： GUI HengjianDepartment of Mathematics, beijing normal university, beijing 100875, china Department of Mathematics Beijing Normal University Beijing China

We consider a robust estimator (t-type regression estimator) of multiple linear regression model by maximizing marginal likelihood of a scaled t-type error *** marginal likelihood can also be applied to the de-correlated response when the withinsubject correlation can be consistently estimated from an initial estimate of the model based on the independent working assumption. This paper shows that such a t-type estimator is consistent.

关键词： t-type regression estimator, M-estimator, one-step estimate, consistency, asymptotic normality.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

THE HAUSDORFF MEASURE FOR THE SAMPLE PATH OF THE WESTWATER PROCESS

引用

Chinese Annals of Mathematics,Series B 1996年第3期17卷 375-388页

作者： ZHOU XIANYIN(Depatment of Mathematics, beijing normal university beijing 100875, china) Department of Mathematics Beijing Normal University Beijing 100875 China

It is proved that φ(s) = s2 log |logs| is the correct function to give the Hausdorff measureof a sample path of the Westwater process.

关键词： Hausdorff measure Wiener process Westwater process Sojourn time

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Infinitely many radial solutions to elliptic prob-lems with critical Sobolev and Hardy terms

引用

Science china Mathematics 2008年第9期51卷 1609-1618页

作者： TANG ZhongWei school of Mathematical Sciences, beijing normal university, beijing 100875,{3. school of Mathematical Sciences Beijing Normal University Beijing China

Let Ω ? ? N be a ball centered at the origin with radius R > 0 and N ? 7, 2* = $ \frac{{2N}} {{N - 2}} $ . We obtain the existence of infinitely many radial solutions for the Dirichlet problem ?Δu = $ \frac{\mu } {{|x|^2 }}u + |u|^{2^* - 2} u + \lambda u $ in Ω, u = 0 on ?Ω for suitable positive numbers μ and λ. Such solutions are characterized by the number of their nodes.

关键词： nodal solutions compactness critical Sobolev and Hardy terms 3.J60 3.B3.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：