散斑法测量膨胀系数与温度的关系

用He-Ne激光散斑照相测量了位移场,通过正交多项式和待定系数法解微分方程,得到了膨胀系数与温度的关系。     

A concept of negative dependence using stochastic ordering

A concept of negative dependence called negative dependence by stochastic ordering is introduced. This concept satisfies various closure properties. It is shown that three models for negetive dependence satisfy it and that it implies the basic negative orthant inequalities. This concept is also satisfied by the multinomial, multivariate hypergeometric. Dirichlet and Dirichlet compound multinomial distributions. Furthermore, the joint distribution of ranks of a sample and the multivariate normal with nonpositive pairwise correlations also satisfy this condition. The positive dependence analog of this condition is also studied.     

Meet,discuss, and segregate!

We present a model of opinion dynamics in which agents adjust continuous opinions as a result of random binary encounters whenever their difference in opinion is below a given threshold. High thresholds yield convergence of opinions toward an average opinion, whereas low thresholds result in several opinion clusters. The model is further generalized to network interactions, threshold heterogeneity, adaptive thresholds, and binary strings of opinions. © 2002 Wiley Periodicals, Inc.     

基于新曝光冲突性消息的网络舆论逆转研究

对网络舆论逆转过程进行研究具有十分重要的意义,它有助于管理者有效引导舆论朝良性方向发展.目前,网络舆论逆转研究主要集中于动力学模型构建与仿真实验分析,其研究结果具有一定的理论价值.然而,这是否适用于真实社交网络环境,还尚未经过测试.为了对舆论逆转过程进行研究,构建了符合实际的模型,并对网络舆论逆转典型事例进行了深入分析.通过观察统计,发现网络舆论逆转具有自身的规律:新曝光冲突性消息是导致舆论发生逆转的根本原因;消息的传播影响着群体的发声与沉默;消息的属性包括传播率、可信度、观点倾向、起始传播时间和消息源中心度决定着舆论逆转的幅度.依据这一规律,设置了消息属性参数,并将消息传播与观点演化过程相结合,构建了网络舆论逆转模型.模型的仿真实验结果表明,新冲突性消息的传播率、可信度和消息源中心度正向影响着舆论逆转幅度,其中可信度较传播率影响更大.新的冲突性消息曝光的时间越早,舆论逆转的速率越快,幅度越大.该模型与实际相符,可为理解和解释网络舆论逆转过程、引导网络舆论提供理论依据.     

中国房地产网络舆情分析

随着互联网技术的运用,基于文本挖掘的网络舆情分析,近年来也越来越受到学术界相关人士的关注。本文结合词云、关联规则、文本倾向性分析等数据挖掘与可视化技术,对2015年第二季度中国房地产网络舆情进行了实证研究与分析,在论证相关方法可行性的基础上,构建了网络舆情分析的基本框架。基于分析本文发现了该季度热点话题的分布与关联,并对各个话题的总体倾向性水平进行了评述,给出了相关政策建议。     

Multivariate power series distributions and Neyman's properties for multinomials

A probelm of J. Neyman (in Classical and Contagious Discrete Distributions (G. P. Patil, Ed.), 1965, pp. 4–14) regarding a characterization of positive and negative multinomial distributions is studied in this paper. Some properties of multivariate power series distributions in general which should be of independent interest are also derived.     

与主观感知相一致的颜色校正评估数据集建立

为了获得与用户主观感知相一致的颜色校正算法和对校正结果进行客观评估,本文首先创建了一个针对颜色校正的数据集ICCD（Image Color Correction Database）.ICCD数据集中的颜色差异涵盖了多种类型和粒度,其中颜色差异类型包括亮度、色相、饱和度、曝光度、对比度以及RGB中的R和G通道,每类颜色差异包括3个修改粒度.本文挑选了6种具有代表性的颜色校正算法对目标图像进行校正,并通过用户调查获得校正结果图像的主观平均得分值.基于ICCD数据集,本文对6种颜色校正算法的性能进行评估,得出在大多数颜色差异和粒度上,Pitie提出的迭代颜色分布转换算法的校正性能最好,同时具有较好的稳定性.最后,本文对14种图像质量评估方法进行评估,挑选出与已有的评估方法相比与主观感知一致性更好的评估方法.     

f-Dissimilarity of Several Distributions in Testing Statistical Hypotheses

Various problems in statistics have been treated by the decision rule, based on the concept of distance between distributions. The aim of this paper is to give an approach for testing statistical hypotheses, using a general class of dissimilarity measures among k 2 distributions. The test statistics are obtained by the replacement, in the expression of the dissimilarity measure, of the unknown parameters by their maximum likelihood estimators. The asymptotic distributions of the resulting test statistics are investigated and the results are applied to multinomial and multivariate normal populations.     

On the performance of objective quality metrics for lightfields

Lightfield (LF) technology has attained significant attention in recent years due to its capability to capture much richer textural and geometric information in the scene compared to the classical 2D representation. The resampling and compression operations on LFs often lead to visual quality degradation, thus, sophisticated visual quality assessment methods play a crucial role to ensure a pleasant viewing experience. To this end, it is necessary to examine the performance of quality assessment methods for LF contents. The paper provides a comprehensive study on the reliability of various objective algorithms for LF quality prediction. Three subjectively-annotated LF data sets were selected and an extensive quality estimation analysis has been conducted using several objective quality assessment methods. In total, 250 LFs (more than 48000 perspective images) were evaluated. The results were compared against human opinion scores using various correlation indices and their statistical significance. Next, a decision-making strategy was adopted to choose the most reliable quality metrics for evaluation of LFs and finally, a metric fusion framework was proposed to further improve the quality prediction accuracy. To best of our knowledge, the benchmark and the analytical methodologies used in this paper are the most comprehensive study on the objective quality assessment methods for LF application.     

基于区间意见的非对称最小成本共识决策问题研究

针对已有共识模型大多是基于精确意见且未考虑决策者意见调整方向约束的不足,引入区间型意见,从最优化角度研究了非对称调整成本下的群决策共识模型。首先,基于区间意见构建了非对称最小成本共识模型。其次,考虑到决策者对不同共识水平的实际需求,通过引入软共识测度,提出了基于区间长度的决策者权重分配方法,据此构建了基于区间意见的非对称最小成本软共识模型。最后,通过政府与污染企业之间关于污染减排决策的实例验证了模型的有效性,并进行了灵敏度分析与比较研究。结果表明:(1)同精确值信息相比,区间意见能够缩减共识成本;(2)与对称成本共识模型相比,非对称调整成本的总共识成本不会随着单位调整成本的增加而无限增大。