论高校实施"教考分离"的优越性与运行机制

本文分析了高校“教考合一”考试制度存在的弊端和实施“教考分离”考试制度的优越性 ,并进一步提出了实施教考分离的运行体制。     

适应网格环境的物流网络研究

随着物流网络这一概念的明确,对物流网络运行环境特性与对应发展模式等问题的探索已接踵而至.本文论证了物流网络应与将逐步兴起的网格环境协调发展的合理性,并展开了对物流网络与网格环境协调发展的框架结构、网络服务资源管理等一些关键问题的进一步分析.     

COVARIANCE MODELS FOR LATTICE DATA

Given observations on an m × n lattice, approximate maximum likelihood estimates are derived for a family of models including direct covariance, spatial moving average, conditional autoregressive and simultaneous autoregressive models. The approach involves expressing the (approximate) covariance matrix of the observed variables in terms of a linear combination of neighbour relationship matrices, raised to a power. The structure is such that the eigenvectors of the covariance matrix are independent of the parameters of interest. This result leads to a simple Fisher scoring type algorithm for estimating the parameters. The ideas are illustrated by fitting models to some remotely sensed data.     

What Determines Trust in Information About Food-Related Risks? Underlying Psychological Constructs

Trust in risk information about food related-hazards may be an important determinant of public reactions to risk information. One of the central questions addressed by the risk communication literature is why some individuals and organizations are trusted as sources of risk information and others are not. Industry and government often lack public trust, whereas other sources (for example, consumer organizations, the quality media, medical doctors) are highly trusted. Problematically, previous surveys and questionnaire studies have utilized questions generated by the investigators themselves to assess public perceptions of trust in different sources. Furthermore, no account of the hazard domain was made. In the first study reported here, semistructured interviewing was used to elicit underpinning constructs determining trust and distrust in different sources providing food-related risk information ( n = 35). In the second study, the repertory grid method was used to elicit the terminology that respondents use to distinguish between different potential food-related information sources ( n = 35), the data being submitted to generalised Procrustes analysis. The results of the two studies were combined and validated in survey research ( n = 888) where factor analysis indicated that knowledge in itself does not lead to trust, but that trusted sources are seen to be characterised by multiple positive attributes. Contrary to previous research, complete freedom does not lead to trust—rather sources which possess moderate accountability are seen to be the most trusted.     

Estimating mixtures of normal distributions via empirical characteristic function

This paper uses the empirical characteristic function (ECF) procedure to estimate the parameters of mixtures of normal distributions. Since the characteristic function is uniformly bounded, the procedure gives estimates that are numerically stable. It is shown that, using Monte Carlo simulation, the finite sample properties of th ECF estimator are very good, even in the case where the popular maximum likelihood estimator fails to exist. An empirical application is illustrated using the monthl excess return of the Nyse value-weighted index.     

平面波照明正交光栅时的Talbot效应

本文根据菲涅尔衍射理论,讨论了平面波照明时,两方向周期d_x≠d_y的正交光栅的Talbot效应。指出,两方向周期满足k_x/k_y=(d_y~2)/(d_x~2)的关系时,才能得到完整信息的Talbot像。并据此,引入了混合Talbot像的新概念。给出了一种较Szwaykowski的方法优越的产生正交光栅的方法。并扩展了Szwaykowski的理论。实验结果和理论吻合很好。     

A weighted likelihood ratio test-based chart for monitoring process mean and variability

In this paper, a new single exponentially weighted moving average (EWMA) control chart based on the weighted likelihood ratio test, referred to as the WLRT chart, is proposed for the problem of monitoring the mean and variance of a normally distributed process variable. It is easy to design, fast to compute, and quite effective for diverse cases including the detection of the decrease in variability and individual observation case. The optimal parameters that can be used as a design aid in selecting specific parameter values based on the average run length (ARL) and the sample size are provided. The in-control (IC) and out-of-control (OC) performance properties of the new chart are compared with some other existing EWMA-type charts. Our simulation results show that the IC run length distribution of the proposed chart is similar to that of a geometric distribution, and it provides quite a robust and satisfactory overall performance for detecting a wide range of shifts in the process mean and/or variability.     

Transformative Homes

ABSTRACT

In the era of global workflows and massive migrations, it has been suggested that the notion of home is breaking free from its material aspects to become a set of exportable routines and practices. On the other hand, it is argued that the materiality of spaces and objects can support migrants' well-being in the new destination. Drawing on the ethnography of a Moroccan household in Rome, Italy, we illustrate how actions pertinent to the material home can favor identity development and the exercise of agency. First, we discuss squatting as a collective action of appropriation and transformation, which led to the identification with a transnational, intercultural category of migrant. Second, we illustrate the activities of furnishing as the locus of syncretic and reflexive processes, in which elements of the host country and themes from the migratory experience are mixed and reinterpreted in novel ways. Our analysis supports the view that the materiality of the home and the actions it affords play a major role in the socio-psychological adjustment of migrants and—on a wider scale—in processes of cultural dynamism and renovation.     

NEAREST NEIGHBOUR ANALYSIS OF UNEQUALLY REPLICATED TRIALS

There has been much work on the use of neighbouring plots to control environmental variation in the analysis of agricultural field experiments. In particular, the Residual Maximum Likelihood Neighbour (REMLN) analysis of Gleeson&Cullis (1987) appears very promising. The application of the REMLN analysis to an unequally replicated field trial augmented with an additional variety planted every six plots in a grid system is here compared with a covariance (COV) analysis using the neighbouring grid or check plot values as the covariate. The results indicate that the REMLN analysis gives more accurate estimates of treatment contrasts than the COV analyses, but that the estimate of treatment means can be biased. The bias depends on the mean of the check plot. This bias can be removed by adjusting the estimates of the treatment means such that their average equals the average of the raw means rather than that of the raw data.     

The effects of different choices of order for autoregressive approximation on the Gaussian likelihood estimates for ARMA models

This paper investigates, by means of Monte Carlo simulation, the effects of different choices of order for autoregressive approximation on the fully efficient parameter estimates for autoregressive moving average models. Four order selection criteria, AIC, BIC, HQ and PKK, were compared and different model structures with varying sample sizes were used to contrast the performance of the criteria. Some asymptotic results which provide a useful guide for assessing the performance of these criteria are presented. The results of this comparison show that there are marked differences in the accuracy implied using these alternative criteria in small sample situations and that it is preferable to apply BIC criterion, which leads to greater precision of Gaussian likelihood estimates, in such cases. Implications of the findings of this study for the estimation of time series models are highlighted.