Graphical Models for Composable Finite Markov Processes

Abstract.  Composable Markov processes were introduced by Schweder (1970) in order to capture the idea that a process can be composed of different components where some of these only depend on a subset of the other components. Here we propose a graphical representation of this kind of dependence which has been called 'local dependence'. It is shown that the graph allows to read off further independencies characterizing the underlying Markov process. Also, some standard methods for inference are adapted to exploit the graphical representation, e.g. for testing local independence.     

Fundamental references from the Western culture

This article presents theoretical elements concerning the ‘nature versus culture’ confrontation as a particular aspect of the worldwide expansion of Western civilization. Several speculations are made concerning the philosophical foundations which have provided the base for the current political and economic mega-scenarios in the contemporary world. We turn our attention to the articulations of the concept of nature with the processes of mondialization of Western culture and with the history of universal culture. Finally, several considerations are made on the dynamics of economic processes on a world scale and projections on the impact of science and technology in the social and political frames that are taking place in the contemporary world.     

基层政府社会风险治理流程优化研究

社会风险治理是社会治理的重要组成部分,增强基层政府社会风险治理能力是推进国家治理体系和治理能力现代化的一大关键。随着我国社会的进一步转型,社会风险呈现出虚拟化、网络化、联动化等新态势,它使得基层政府社会风险治理面临着新的挑战。因此,需要从流程优化的角度,对基层政府社会风险治理的机制与方式进行创新,从而提高基层政府社会风险治理的水平。     

Challenges and Opportunities for Research on Same‐Sex Relationships

Research on same‐sex relationships has informed policy debates and legal decisions that greatly affect American families, yet the data and methods available to scholars studying same‐sex relationships have been limited. In this article the authors review current approaches to studying same‐sex relationships and significant challenges for this research. After exploring how researchers have dealt with these challenges in prior studies, the authors discuss promising strategies and methods to advance future research on same‐sex relationships, with particular attention given to gendered contexts and dyadic research designs, quasi‐experimental designs, and a relationship biography approach. Innovation and advances in the study of same‐sex relationships will further theoretical and empirical knowledge in family studies more broadly and increase understanding of different‐sex as well as same‐sex relationships.     

新兴产业政策决策过程中的不确定性管理研究——基于物联网产业的宏观政策决策过程的案例

采用纵贯研究、内容分析、深度访谈相结合的定性研究方法,以推动我国物联网产业发展的3个宏观政策决策过程为研究对象,旨在讨论政企互动是如何帮助政府进行不确定性管理的.研究结论表明:新兴产业的宏观政策决策是由数个存在递进关系的渐进式阶段组成,而每个渐进式事项的解决依赖于众多在政企互动中形成的微观政策工具的实施.政企互动帮助政策决策者通过4种机制(信息获取、行动协调、企业行动承诺和政府政策承诺)实现了对因信息缺乏以及对产业行动者资源依赖所造成的不确定性的管理.     

Stationary bootstrapping for panel cointegration tests under cross-sectional dependence

Stationary bootstrapping is applied to panel cointegration tests which are based on the ordinary least-squares estimator and the seemingly unrelated regression (SUR) estimator of the residual unit root. Large sample validity of stationary bootstrapping is established. A finite sample experiment reveals that size performances of the bootstrap tests are much less sensitive to cross-sectional correlation than those of existing tests and a test based on the SUR estimator has substantially better power than existing tests.     

Modelling change in cognitive understanding with finite mixtures

Psychological theories often posit the existence of several different states. Individuals are viewed as belonging to one of the states at a given age, but with development pass to another state. A main problem in evaluating such theories is representing the transition from one state to another over age. A stochastic transition framework is proposed which should be useful in many different settings. The model is illustrated with data from a cognitive development task.     

Integer-valued autoregressive processes with periodic structure

In this paper the periodic integer-valued autoregressive model of order one with period T, driven by a periodic sequence of independent Poisson-distributed random variables, is studied in some detail. Basic probabilistic and statistical properties of this model are discussed. Moreover, parameter estimation is also addressed. Specifically, the methods of estimation under analysis are the method of moments, least squares-type and likelihood-based ones. Their performance is compared through a simulation study.     

Obtaining prediction intervals for FARIMA processes using the sieve bootstrap

The sieve bootstrap (SB) prediction intervals for invertible autoregressive moving average (ARMA) processes are constructed using resamples of residuals obtained by fitting a finite degree autoregressive approximation to the time series. The advantage of this approach is that it does not require the knowledge of the orders, p and q, associated with the ARMA(p, q) model. Up until recently, the application of this method has been limited to ARMA processes whose autoregressive polynomials do not have fractional unit roots. The authors, in a 2012 publication, introduced a version of the SB suitable for fractionally integrated autoregressive moving average (FARIMA (p,d,q)) processes with 0<d<0.5 and established its asymptotic validity. Herein, we study the finite sample properties this new method and compare its performance against an older method introduced by Bisaglia and Grigoletto in 2001. The sieve bootstrap (SB) method is a numerically simpler alternative to the older method which requires the estimation of p, d, and q at every bootstrap step. Monte-Carlo simulation studies, carried out under the assumption of normal, mixture of normals, and exponential distributions for the innovations, show near nominal coverages for short-term and long-term SB prediction intervals under most situations. In addition, the sieve bootstrap method yields better coverage and narrower intervals compared to the Bisaglia–Grigoletto method in some situations, especially when the error distribution is a mixture of normals.