Improved deviance goodness of fit statistics for a gamma regression model

A gamma regression model with an exponential link function for the means Is considered. Moment properties of the deviance statistics based on maximum likelihood and weighted least squares fits are used to define modified deviance statistics which provide alternative global goodness of fit tests. The null distribution properties of the deviances and modified deviances are compared with those of the approximating chi-square distribution and It is shown that the use of the modified deviances gives much better control over the significance levels of the tests.     

Modified minimax estimation of regression coefficients

Working with the linear regression model (1.1) and having the extraneous information (1.2) about regression coefficients the problem exists how to build estimators (1.3) with the risk (1.4) which enable to utilize the known information in order to reduce their risk as compared with the risk (1.6) of the LSE (1.5). Solution of this problem is known for the positive definite matrix T, namely in form for estimators (1.8) and (1.10).First, it is shown that the proposed estimators (2.6),(2.9) and (2.16) based on psedoinversions of the matrix L represent the solution of the problem of the positive semidefinite matrix T=L'L.Further, the problem of interpretability of estimators in the sense of the inequality (3.1) exists; it is shown that all mentioned estimators are at least partially interpretable in the sense of requirements (3.2) or (3.10).     

PARAMETER ESTIMATION AND APPLICATIONS FOR A GENERALISATION OF THE BETA-BINOMIAL DISTRIBUTION

A three-parameter generalisation of the beta-binomial distribution (BBD) derived by Chandon (1976) is examined. We obtain the maximum likelihood estimates of the parameters and give the elements of the information matrix. To exhibit the applicability of the generalised distribution we show how it gives an improved fit over the BBD for magazine exposure and consumer purchasing data. Finally we derive an empirical Bayes estimate of a binomial proportion based on the generalised beta distribution used in this study.     

一类有广泛适用性的综合控制算法

将闭环极点配置、史密斯予估和自适应控制策略有机地结合起来,提出了一类单、多变量自校正史密斯予估综合控制算法。并用数字仿真进行了验证。     

玉林话“好+形容词+定”结构的音变及其意义

玉林话中的“好 +形容词 +定”结构是由副词“好” (相当于现代汉语的“很”)加单音节或双音节形容词和助词“定”组成的结构形式。从语音构成看 ,有本调和变音之别 ,其词汇意义也随之改变 ,读本调时表示程度重 ,读变音时则常表示程度轻 ,且大多数带有令人喜爱的色彩。该结构主要作谓语和补语。言语色彩上可随形容词意义的不同而有褒贬上的区别。     

The Media and Genetically Modified Foods: Evidence in Support of Social Amplification of Risk

Empirical examinations of the "social amplification of risk" framework are rare, partly because of the difficulties in predicting when conditions likely to result in amplification effects will occur. This means that it is difficult to examine changes in risk perception that are contemporaneous with increases and/or decreases in social or media discussion of the risks associated with a particular risk event. However, the collection of attitude data before, during, and after the increased reporting of the risks of genetically modified food in the United Kingdom (spring 1999) has demonstrated that people's risk perceptions do increase and decrease in line with what might be expected upon examination of the amplification and attenuation mechanisms integral to the framework. Perceptions of benefit, however, appeared to be permanently depressed by negative reporting about genetically modified food. Trust in regulatory institutions with responsibility for protecting the public was not affected. It was concluded that the social amplification of risk framework is a useful framework for beginning to explain the potential impact on risk perceptions of a risk event, particularly if that risk event is presented to the public as a new hazard occurring in a crisis context.     

Estimation under modified Weibull distribution based on right censored generalized order statistics

In this paper, the maximum likelihood (ML) and Bayes, by using Markov chain Monte Carlo (MCMC), methods are considered to estimate the parameters of three-parameter modified Weibull distribution (MWD(β, τ, λ)) based on a right censored sample of generalized order statistics (gos). Simulation experiments are conducted to demonstrate the efficiency of the proposed methods. Some comparisons are carried out between the ML and Bayes methods by computing the mean squared errors (MSEs), Akaike's information criteria (AIC) and Bayesian information criteria (BIC) of the estimates to illustrate the paper. Three real data sets from Weibull(α, β) distribution are introduced and analyzed using the MWD(β, τ, λ) and also using the Weibull(α, β) distribution. A comparison is carried out between the mentioned models based on the corresponding Kolmogorov–Smirnov (K–S) test statistic, {AIC and BIC} to emphasize that the MWD(β, τ, λ) fits the data better than the other distribution. All parameters are estimated based on type-II censored sample, censored upper record values and progressively type-II censored sample which are generated from the real data sets.     

糖酵解反应模型双曲型反应-扩散方程的稳定性和化学振荡

研究了糖酵解反应模型（修正Ｓｅｌｋｏｖ模型）双曲型反应－扩散方程的稳定性和化学振荡．与抛物型方程的结果比较表明，抛物型系统是双曲型系统当反应－扩散数增至无穷大时的特殊情况；双曲型系统不存在波速可能趋于无穷大的问题；二者的稳定性区域存在很大区别；双曲型系统更适合于用来研究糖酵解反应中的化学振荡．     

我国转基因作物产业化的法治管理现状及对策——基于美国转基因稻米污染事件的分析

美国发生的转基因稻米LLRICE601污染事件引起了世界各国的广泛关注。美国健全的法律制度，使该事件的处理具有完善的制度保证。我国在转基因作物产业化过程中存在着制度缺乏和执法不严的问题。我国应构建转基因作物产业化安全评价制度、公众参与制度和救济赔偿制度，实现转基因作物技术的可持续发展。