Diagnostics for dependence within time series extremes

Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed.     

虚拟产业群的运作管理模式研究

虚拟产业群是一种松散的企业网络组织,在网络信息技术的支持下成为虚拟企业构建与运作的基础平台。基于这一出发点,本文通过分析与研究虚拟产业群运作的目标、创建过程、组织结构形式、运作过程主要活动及必需的基础设施建设等问题,提出了虚拟产业群运作管理的基本模式。同时,为充分理解这一模式,文后给出了两个实际案例。最后,总结了虚拟产业群运作对虚拟企业的基础作用与价值所在。     

Robust Smoothed Rank Estimation Methods for Accelerated Failure Time Model Allowing Clusters

Smoothed Gehan rank estimation methods are widely used in accelerated failure time (AFT) models with/without clusters. However, most methods are sensitive to outliers in the covariates. In order to solve this problem, we propose robust approaches based on the smoothed Gehan rank estimation methods for the AFT model, allowing for clusters by employing two different weight functions. Simulation studies show that the proposed methods outperform existing smoothed rank estimation methods regarding their biases and standard deviations when there are outliers in the covariates. The proposed methods are also applied to a real dataset from the “Major cardiovascular interventions” study.     

产业集群持续竞争优势的动态能力分析视角

传统理论对于产业集群持续竞争优势的研究多是基于稳定或渐变的环境来分析的,因而在动态复杂环境下很难适用。动态能力理论是战略管理领域研究的一个前沿理论,它为我们解释动态复杂环境下的产业集群持续竞争优势问题提出了一个新的分析视角。     

Distance sampling methodology

We consider the method of distance sampling described by Buckland, Anderson, Burnham and Laake in 1993. We explore the properties of the methodology in simple cases chosen to allow direct and accessible comparisons of distance sampling in the design- and model-based frameworks. In particular, we obtain expressions for the bias and variance of the distance sampling estimator of object density and for the expected value of the recommended analytic variance estimator within each framework. These results enable us to clarify aspects of the performance of the methodology which may be of interest to users and potential users of distance sampling.     

产业集群技术创新的相关理论

产业集群研究的一个主要课题是产业集群和技术创新的关系。通过对产业集群技术创新的缄默知识论和创新环境论进行阐述,指出缄默知识是产业集群更重要的知识资源,是产业集群技术创新成功的一个不可或缺的变量;环境是创新赖以进行的一个重要意境,为产业集群形成社会支持系统提供了条件,创新过程的结果就会形成产业集群。     

与鼻音谐声的上古拟音问题初探

考察谐声关系可得出《说文》谐声字具有不同的历史层级关系；日母和明母的谐声关系不能作为复辅音的证据。从谐声的系统性来说，拟清鼻流音的证据还不充分。     

A cluster problem as defined by nearest neighbours

Randomly generated points in R^d are connected to their nearest neighbours (Euclidean distance). The resulting connected clusters of points are studied. This paper examines questions related to the collection of clusters formed and to the internal structure of a cluster. In particular, the one-dimensional structure is examined in detail.     

Context and differentiation: Development of the wine industry in three Canadian regions

This paper uses the cluster concept to explain the key factors of the development of wineries in Canada. First, we describe the salient features of the Canadian wine industry. Then we investigate the key factors of the emergence of the wine clusters in three different regions and discuss the structural and institutional problems hampering the development of the wine industry. Finally, differences across wine regions are discussed and assessed in relation to the cluster concept.     

产业集群学习行为研究

学习是集群持续发展的动力源泉。以集群学习为研究对象,首先界定了集群学习的涵义,提出了集群的网络学习范式,然后在此基础上从文化基础、稳定性、知识传播方式以及系统学习等几个方面对集群学习行为进行了分析和研究。