期刊文献+
共找到750篇文章
< 1 2 38 >
每页显示 20 50 100
A Novel Hybrid Method for Measuring the Spatial Autocorrelation of Vehicular Crashes: Combining Moran’s Index and Getis-Ord G<sub>i</sub><sup style='margin-left:-7px;'>*</sup>Statistic 被引量:2
1
作者 Azad Abdulhafedh 《Open Journal of Civil Engineering》 2017年第2期208-221,共14页
Spatial autocorrelation is a measure of the correlation of an observation with other observations through space. Most statistical analyses are based on the assumption that the values of observations are independent of... Spatial autocorrelation is a measure of the correlation of an observation with other observations through space. Most statistical analyses are based on the assumption that the values of observations are independent of one another. Spatial autocorrelation violates this assumption, because observations at near-by locations are related to each other, and hence, the consideration of spatial autocorrelations has been gaining attention in crash data modeling in recent years, and research have shown that ignoring this factor may lead to a biased estimation of the modeling parameters. This paper examines two spatial autocorrelation indices: Moran’s Index;and Getis-Ord Gi* statistic to measure the spatial autocorrelation of vehicle crashes occurred in Boone County roads in the state of Missouri, USA for the years 2013-2015. Since each index can identify different clustering patterns of crashes, therefore this paper introduces a new hybrid method to identify the crash clustering patterns by combining both Moran’s Index and Gi*?statistic. Results show that the new method can effectively improve the number, extent, and type of crash clustering along roadways. 展开更多
关键词 spatial AUTOCORRELATION morans Index Getis-Ord Gi* statistic Vehicle Crashes
下载PDF
THE LAW OF ITERATED LOGARITHM FOR R/S STATISTICS 被引量:5
2
作者 林正炎 《Acta Mathematica Scientia》 SCIE CSCD 2005年第2期326-330,共5页
A law of iterated logarithm for R/S statistics with the help of the strong approximations of R/S statistics by functions of a Wiener process is shown.
关键词 R/s statistics law of iterated logarithm strong approximation
下载PDF
PRECISE RATES IN THE LAW OF THE ITERATED LOGARITHM FOR R/S STATISTICS 被引量:3
3
作者 Wu Hongmei Wen Jiwei 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2006年第4期461-466,共6页
Let{Xn;n≥1}be a sequence of i.i.d, random variables with finite variance,Q(n)be the related R/S statistics. It is proved that lim ε↓0 ε^2 ∑n=1 ^8 n log n/1 P{Q(n)≥ε√2n log log n}=2/1 EY^2,where Y=sup0≤t... Let{Xn;n≥1}be a sequence of i.i.d, random variables with finite variance,Q(n)be the related R/S statistics. It is proved that lim ε↓0 ε^2 ∑n=1 ^8 n log n/1 P{Q(n)≥ε√2n log log n}=2/1 EY^2,where Y=sup0≤t≤1B(t)-inf0≤t≤sB(t),and B(t) is a Brownian bridge. 展开更多
关键词 law of the iterated logarithm R/s statistics tail probability.
下载PDF
Post electrical or lightning injury syndrome: a proposal for an American Psychiatric Association's Diagnostic and Statistical Manual formulation with implications for treatment 被引量:3
4
作者 Christopher J.Andrews Andrew D.Reisner Mary Ann Cooper 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第9期1405-1412,共8页
In the past, victims of electrical and lightning injuries have been assessed in a manner lacking a system- atic formulation, and against ad hoc criteria, particularly in the area of neuropsychological disability. In t... In the past, victims of electrical and lightning injuries have been assessed in a manner lacking a system- atic formulation, and against ad hoc criteria, particularly in the area of neuropsychological disability. In this manner patients have, for example, only been partially treated, been poorly or incorrectly diagnosed, and have been denied the full benefit of compensation for their injuries. This paper contains a proposal for diagnostic criteria particularly for the neuropsychological aspects of the post injury syndrome. It pays attention to widely published consistent descriptions of the syndrome, and a new cluster analysis of post electrical injury patients. It formulates a proposal which could be incorporated into future editions of the American Psychiatric Association's Diagnostic and Statistical Manual (DSM). The major neuropsycholog- ical consequences include neurocognitive dysfunction, and memory subgroup dysfunction, with ongoing consequences, and sometimes including progressive or delayed psychiatric, cognitive, and/or neurological symptoms. The proposed diagnostic criteria insist on a demonstrated context for the injury, both specifying the shock circumstance, and also physical consequences. It allows for a certain delay in onset of symptoms. It recognizes exclusory conditions. The outcome is a proposal for a DSM classification for the post electrical or lightning injury syndrome. This proposal is considered important for grounding patient treatment, and for further treatment trials. Options for treatment in electrical or lightning injury are summarised, and future trials are foreshadowed. 展开更多
关键词 electrical injury lightning injury NEUROPsYCHOLOGY NEUROPsYCHIATRY INJURY American Psychiatric Association's Diagnostic and statistical Manual
下载PDF
基于CSLE的泛第三极地区土壤侵蚀强度空间分布特征
5
作者 刘子玥 章文波 +4 位作者 殷兵 杨勤科 魏欣 刘宝元 殷水清 《水土保持研究》 CSCD 北大核心 2024年第3期1-9,共9页
[目的]定量评估泛第三极地区的土壤侵蚀状况,明确土壤侵蚀的分布特征,以期为土壤侵蚀的科学防治提供依据。[方法]基于分层不等概系统抽样方法,共布设31 406个调查单元。利用中国土壤流失方程CSLE计算泛第三极地区土壤侵蚀速率,并利用莫... [目的]定量评估泛第三极地区的土壤侵蚀状况,明确土壤侵蚀的分布特征,以期为土壤侵蚀的科学防治提供依据。[方法]基于分层不等概系统抽样方法,共布设31 406个调查单元。利用中国土壤流失方程CSLE计算泛第三极地区土壤侵蚀速率,并利用莫兰指数(I)探讨其分布特征。[结果](1)泛第三极地区平均土壤侵蚀速率为162.73 t/(km^(2)·a),水土流失面积比例为7.75%,土壤侵蚀速率超过500 t/(km^(2)·a)的地区主要位于西亚、东亚和南亚;(2)土壤侵蚀存在明显的空间聚集性(I=0.920 9),以高高型和低低型聚集为主,高高型聚集主要分布在西亚北部、南亚北部和西南部以及中国的东北、黄土高原和西藏南部;(3)草地、灌丛和耕地是土壤侵蚀较严重的土地利用类型,其中>1 000 m的草地、>500 m的灌丛和耕地的土壤侵蚀更严重,超过25%的土地都发生了水土流失,平均土壤侵蚀速率变化于426.85~683.72 t/(km^(2)·a)。[结论]海拔介于1 000~6 000 m的草地、500~4 000 m的灌丛以及1 000~4 000 m的耕地是泛第三极地区土壤侵蚀发生的重点区域,需特别关注。 展开更多
关键词 土壤侵蚀 泛第三极 空间分布 莫兰指数
下载PDF
Finding Statistically Significant Communities in Networks with Weighted Label Propagation 被引量:2
6
作者 Wei Hu 《Social Networking》 2013年第3期138-146,共9页
Various networks exist in the world today including biological, social, information, and communication networks with the Internet as the largest network of all. One salient structural feature of these networks is the ... Various networks exist in the world today including biological, social, information, and communication networks with the Internet as the largest network of all. One salient structural feature of these networks is the formation of groups or communities of vertices that tend to be more connected to each other within the same group than to those outside. Therefore, the detection of these communities is a topic of great interest and importance in many applications and different algorithms including label propagation have been developed for such purpose. Speaker-listener label propagation algorithm (SLPA) enjoys almost linear time complexity, so desirable in dealing with large networks. As an extension of SLPA, this study presented a novel weighted label propagation algorithm (WLPA), which was tested on four real world social networks with known community structures including the famous Zachary's karate club network. Wilcoxon tests on the communities found in the karate club network by WLPA demonstrated an improved statistical significance over SLPA. Withthehelp of Wilcoxon tests again, we were able to determine the best possible formation of two communities in this network relative to the ground truth partition, which could be used as a new benchmark for assessing community detection algorithms. Finally WLPA predicted better communities than SLPA in two of the three additional real social networks, when compared to the ground truth. 展开更多
关键词 Community Detection social NETWORKs WEIGHTED LABEL Propagation statistical significance Zachary’s KARATE CLUB Network
下载PDF
Perceiving China's Energy Development from the World Key Energy Statistics 被引量:2
7
作者 Zheng Jianchao China Guangdong Nuclear Power Group, Jia Yulu 《Electricity》 2008年第4期27-29,共3页
As the world's authoritative organization on energy information, the International Energy Agency (IEA), which was founded in 1974, releases Key World Energy Statistics every year from 1997 (hereinafter referred to... As the world's authoritative organization on energy information, the International Energy Agency (IEA), which was founded in 1974, releases Key World Energy Statistics every year from 1997 (hereinafter referred to as the "Key Data"). The "Key Data" released in 2007 announced the 2005 statistics, and also provided the 1973 statistics for comparison. From the published data, we can clearly find the development path and trend of the world energy and power industry. Also, China's strong development momentum, high- speed growth of energy consumption and the enormous challenges in the sustainable energy supply are especially noticeable. This paper reviewed the "Key Data" to perceive China's Energy Development. The analysis and interpretation of these data are purely from the author's point of view. 展开更多
关键词 OECD AsIA Perceiving China’s Energy Development from the World Key Energy statistics World IEA
下载PDF
Statistic PID Tracking Control for Non-Gaussian Stochastic Systems Based on T-S Fuzzy Model 被引量:3
8
作者 Yang Yi Hong Shen Lei Gu 《International Journal of Automation and computing》 EI 2009年第1期81-87,共7页
A new robust proportional-integral-derivative (PID) tracking control framework is considered for stochastic systems with non-Gaussian variable based on B-spline neural network approximation and T-S fuzzy model ident... A new robust proportional-integral-derivative (PID) tracking control framework is considered for stochastic systems with non-Gaussian variable based on B-spline neural network approximation and T-S fuzzy model identification. The tracked object is the statistical information of a given target probability density function (PDF), rather than a deterministic signal. Following B-spline approximation to the integrated performance function, the concerned problem is transferred into the tracking of given weights. Different from the previous related works, the time delay T-S fuzzy models with the exogenous disturbances are applied to identify the nonlinear weighting dynamics. Meanwhile, the generalized PID controller structure and the improved convex linear matrix inequalities (LMI) algorithms are proposed to fulfil the tracking problem. Furthermore, in order to enhance the robust performance, the peak-to-peak measure index is applied to optimize the tracking performance. Simulations are given to demonstrate the efficiency of the proposed approach. 展开更多
关键词 Non-Gaussian systems probability density function statistic tracking control T-s fuzzy model proportional-integralderivative control.
下载PDF
Fractals Generated by Statistical Contraction Operators
9
作者 Hu Di\|he School of Mathematics and Statistics, Wuhan University, Wuhan 430072, Hubei, China 《Wuhan University Journal of Natural Sciences》 CAS 2002年第3期274-280,共7页
In the theory of random fractal, there are two important classes of random sets, one is the class of fractals generated by the paths of stochastic processes and another one is the class of factals generated by statist... In the theory of random fractal, there are two important classes of random sets, one is the class of fractals generated by the paths of stochastic processes and another one is the class of factals generated by statistical contraction operators. Now we will introduce some things about the probability basis and fractal properties of fractals in the last class. The probability basis contains (1) the convergence and measurability of a random recursive setK(ω) as a random element, (2) martingals property. The fractal properties include (3) the character of various similarity, (4) the separability property, (5) the support and zero-one law of distributionP k =P·K ?1, (6) the Hausdorff dimension and Hausdorff exact measure function. 展开更多
关键词 statistical contraction operator FRACTAL statistically self-similar set a. s. self-similar set
下载PDF
A Bayesian multi-model inference methodology for imprecise momentindependent global sensitivity analysis of rock structures
10
作者 Akshay Kumar Gaurav Tiwari 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期840-859,共20页
Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(i.e.type of distribution type and its parameters)of input rock properties emanating du... Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(i.e.type of distribution type and its parameters)of input rock properties emanating due to the small size of datasets while mapping the relative importance of properties to the model response.This paper proposes an augmented Bayesian multi-model inference(BMMI)coupled with GSA methodology(BMMI-GSA)to address this issue by estimating the imprecision in the momentindependent sensitivity indices of rock structures arising from the small size of input data.The methodology employs BMMI to quantify the epistemic uncertainties associated with model type and parameters of input properties.The estimated uncertainties are propagated in estimating imprecision in moment-independent Borgonovo’s indices by employing a reweighting approach on candidate probabilistic models.The proposed methodology is showcased for a rock slope prone to stress-controlled failure in the Himalayan region of India.The proposed methodology was superior to the conventional GSA(neglects all epistemic uncertainties)and Bayesian coupled GSA(B-GSA)(neglects model uncertainty)due to its capability to incorporate the uncertainties in both model type and parameters of properties.Imprecise Borgonovo’s indices estimated via proposed methodology provide the confidence intervals of the sensitivity indices instead of their fixed-point estimates,which makes the user more informed in the data collection efforts.Analyses performed with the varying sample sizes suggested that the uncertainties in sensitivity indices reduce significantly with the increasing sample sizes.The accurate importance ranking of properties was only possible via samples of large sizes.Further,the impact of the prior knowledge in terms of prior ranges and distributions was significant;hence,any related assumption should be made carefully. 展开更多
关键词 Bayesian inference Multi-model inference statistical uncertainty Global sensitivity analysis(GsA) Borgonovo’s indices Limited data
下载PDF
Statistical Communique of the People's Republic of China on the 1998 National Economic and Social Development 被引量:1
11
作者 State Statistics Bureau 《经济研究参考》 1999年第30期47-55,共9页
In 1998, facing the complicated and severe domestic and internationaleconomic environment, people of all nationalities, under the correct lead-ership of the Central Party Committee and the State Council, implement-ed ... In 1998, facing the complicated and severe domestic and internationaleconomic environment, people of all nationalities, under the correct lead-ership of the Central Party Committee and the State Council, implement-ed a series of policies aiming at increasing input and expanding domesticdemand. Difficulties brought about by the Asian financial crisis and dev-astating flooding were overcome, various reforms were further deepened,and economic growth was promoted, resulting in great achievements at-tracting worldwide attention. 展开更多
关键词 OVER statistical Communique of the People’s Republic of China on the 1998 National Economic and social Development
下载PDF
Forecasting S&P 500 Stock Index Using Statistical Learning Models 被引量:2
12
作者 Chongda Liu Jihua Wang +1 位作者 Di Xiao Qi Liang 《Open Journal of Statistics》 2016年第6期1067-1075,共9页
Forecasting the movement of stock market is a long-time attractive topic. This paper implements different statistical learning models to predict the movement of S&P 500 index. The S&P 500 index is influenced b... Forecasting the movement of stock market is a long-time attractive topic. This paper implements different statistical learning models to predict the movement of S&P 500 index. The S&P 500 index is influenced by other important financial indexes across the world such as commodity price and financial technical indicators. This paper systematically investigated four supervised learning models, including Logistic Regression, Gaussian Discriminant Analysis (GDA), Naive Bayes and Support Vector Machine (SVM) in the forecast of S&P 500 index. After several experiments of optimization in features and models, especially the SVM kernel selection and feature selection for different models, this paper concludes that a SVM model with a Radial Basis Function (RBF) kernel can achieve an accuracy rate of 62.51% for the future market trend of the S&P 500 index. 展开更多
关键词 statistical Learning Models s&P 500 Index Feature selection sVM RBF Kernel
下载PDF
Statistics on China's 1996 Social Development
13
《China Population Today》 1997年第2期11-12,共2页
China has achieved new progress in education and has made headway in reform of the management system of higher education.In 1996。there were 1。032 universities and colleges and 1,138 institutions of higher learn-ing ... China has achieved new progress in education and has made headway in reform of the management system of higher education.In 1996。there were 1。032 universities and colleges and 1,138 institutions of higher learn-ing for adult education,22 and 18 fewer respectively than in 1995 due to read justment. 展开更多
关键词 statistics DEVELOPMENT sOCIAL China’s
下载PDF
Statistics of China's Foreign Trade
14
《China's Foreign Trade》 1995年第8期46-48,共3页
关键词 JUN statistics of China’s Foreign Trade 110 Us
下载PDF
Statistics of China's Foreign Trade——(October 1994—December 1994)
15
《China's Foreign Trade》 1995年第5期47-49,共3页
关键词 DCC December 1994 October 1994 statistics of China’s Foreign Trade
下载PDF
Statistical Communique of 2001 China's Economic and Social Development
16
《China's Foreign Trade》 2002年第3期48-49,共2页
关键词 statistical Communique of 2001 China’s Economic and social Development DOWN Us
下载PDF
Probabilistic, Statistical and Algorithmic Aspects of the Similarity of Texts and Application to Gospels Comparison
17
作者 Soumaila Dembele Gane Samb Lo 《Journal of Data Analysis and Information Processing》 2015年第4期112-127,共16页
The fundamental problem of similarity studies, in the frame of data-mining, is to examine and detect similar items in articles, papers, and books with huge sizes. In this paper, we are interested in the probabilistic,... The fundamental problem of similarity studies, in the frame of data-mining, is to examine and detect similar items in articles, papers, and books with huge sizes. In this paper, we are interested in the probabilistic, and the statistical and the algorithmic aspects in studies of texts. We will be using the approach of k-shinglings, a k-shingling being defined as a sequence of k consecutive characters that are extracted from a text (k ≥ 1). The main stake in this field is to find accurate and quick algorithms to compute the similarity in short times. This will be achieved in using approximation methods. The first approximation method is statistical and, is based on the theorem of Glivenko-Cantelli. The second is the banding technique. And the third concerns a modification of the algorithm proposed by Rajaraman et al. ([1]), denoted here as (RUM). The Jaccard index is the one being used in this paper. We finally illustrate these results of the paper on the four Gospels. The results are very conclusive. 展开更多
关键词 sIMILARITY Web MINING Jaccard sIMILARITY RU Algorithm Minhashing Data MINING shingling Bible’s GOsPELs Glivenko-Cantelli EXPECTED sIMILARITY statisticAL Estimation
下载PDF
An Alternative Approach to AIC and Mallow’s Cp Statistic-Based Relative Influence Measures (RIMS) in Regression Variable Selection
18
作者 Umeh Edith Uzoma Obulezi Okechukwu Jeremiah 《Open Journal of Statistics》 2016年第1期70-75,共6页
Outlier detection is an important data screening type. RIM is a mechanism of outlier detection that identifies the contribution of data points in a regression model. A BIC-based RIM is essentially a technique develope... Outlier detection is an important data screening type. RIM is a mechanism of outlier detection that identifies the contribution of data points in a regression model. A BIC-based RIM is essentially a technique developed in this work to simultaneously detect influential data points and select optimal predictor variables. It is an addition to the body of existing literature in this area of study to both having an alternative to the AIC and Mallow’s Cp Statistic-based RIM as well as conditions of no influence, some sort of influence and perfectly single outlier data point in an entire data set which are proposed in this work. The method is implemented in R by an algorithm that iterates over all data points;deleting data points one at a time while computing BICs and selecting optimal predictors alongside RIMs. From the analyses done using evaporation data to compare the proposed method and the existing methods, the results show that the same data cases selected as having high influences by the two existing methods are also selected by the proposed method. The three methods show same performance;hence the relevance of the BIC-based RIM cannot be undermined. 展开更多
关键词 Relative Influence Measure (RIM) BIC AIC Mallow’s Cp statistic Cook’s Distance
下载PDF
First and Second Order Statistics Features for Classification of Magnetic Resonance Brain Images
19
作者 Namita Aggarwal R. K. Agrawal 《Journal of Signal and Information Processing》 2012年第2期146-153,共8页
In literature, features based on First and Second Order Statistics that characterizes textures are used for classification of images. Features based on statistics of texture provide far less number of relevant and dis... In literature, features based on First and Second Order Statistics that characterizes textures are used for classification of images. Features based on statistics of texture provide far less number of relevant and distinguishable features in comparison to existing methods based on wavelet transformation. In this paper, we investigated performance of texture-based features in comparison to wavelet-based features with commonly used classifiers for the classification of Alzheimer’s disease based on T2-weighted MRI brain image. The performance is evaluated in terms of sensitivity, specificity, accuracy, training and testing time. Experiments are performed on publicly available medical brain images. Experimental results show that the performance with First and Second Order Statistics based features is significantly better in comparison to existing methods based on wavelet transformation in terms of all performance measures for all classifiers. 展开更多
关键词 Alzheimer’s Disease Magnetic REsONANCE Imaging Feature Extraction Discrete WAVELET TRANsFORM FIRsT and second Order statistical FEATUREs
下载PDF
China's Top Ten(Superlative Statistics in China)
20
《China & The World Cultural Exchange》 1999年第3期96-96,共1页
关键词 China’s Top Ten superlative statistics in China
下载PDF
上一页 1 2 38 下一页 到第
使用帮助 返回顶部