Estimating the First- and Second-Order Parameters of a Heavy-Tailed Distribution

This paper suggests censored maximum likelihood estimators for the first‐ and second‐order parameters of a heavy‐tailed distribution by incorporating the second‐order regular variation into the censored likelihood function. This approach is different from the bias‐reduced maximum likelihood method proposed by Feuerverger and Hall in 1999. The paper derives the joint asymptotic limit for the first‐ and second‐order parameters under a weaker assumption. The paper also demonstrates through a simulation study that the suggested estimator for the first‐order parameter is better than the estimator proposed by Feuerverger and Hall although these two estimators have the same asymptotic variances.     

教育政策何以影响高校发展

教育政策既可以成为教育发展的动力,也会成为阻碍教育发展的力量,其关键在于教育政策本身。教育政策要成为教育发展的推动力量,就要考虑政策制定的绩效性、科学化和民主化。根据这些原则,我国高校的收费政策,应该以属地化原则(学生生源地)为依据制定收费标准,以体现政策的科学性;重点高校建设政策,应该以动态化原则取代静态化,以体现政策的民主化;高校资助政策的实施,应该以多样化、层次化为原则,以体现教育政策的绩效性。     

整合与创新:清代广西壮人接受杜诗的变异学研究

文学变异学重在研究跨民族交流中文学文本的变异情况,而杜诗在广西壮人的接受变异上鲜有涉猎,本文以此为案例从跨时空的传播、文化传统的激活以及文学创作的创新等角度来发掘其传播中的双向互动性、对中华文化的共同建构性,从而发现中华民族的历史就是一种多民族间互补互济的共同发展过程。     

清人词体发生诸说检讨

清人根据各自对词体特性的认识展开对词体发生问题的探究与解说。从“学”而言,清人大体上将词体发生时间定在盛唐至五代,并认为词体由诗与乐府衍变而来。关于词体生成方式,清人主要有“文体代嬗”与“音律递变”两种观点,其中以“音律递变论”为主流观点。从“术”而言,清人探究词体发生问题的着眼点主要在文体和音乐两个向度。在具体问题的论述上,清人注重文献实证,同时又能对不同视角的观点博观约取、汲异补正,显示出崇尚实证的学术路径与包容通变的学术思想。     

Estimation of the mutagenic potency of environmental chemicals using short-term bioassay

The Ames Salmonella test is a widely used bioassay method for assessing the mutagenic potency of a potential carcinogen. The test is quick and reliable, and exploits the correlation that exists between mutagenic potential and carcinogenic potential. The data for this case study came from an international study involving 20 laboratories in nine countries. The laboratories participated in a designed experiment in which substances (complex chemical mixtures of the type encountered in the environment) were evaluated for mutagenicity using the Ames test. A stringent protocol was followed. The study's principal aim was to investigate intra- and inter-laboratory variation in test results. The data consist of counts of revertant Salmonella colonies at each of six dose levels of a substance. The data were obtained for each of five test substances from each participating laboratory. The bioassays were carried out according to a prescribed factorial experimental design. Three sets of analysts participated in this case study. They were asked to model the dose-response relationship for two substances, to develop an index of the strength of the relationship, and to assess intra- and inter-laboratory variation in bioassay results.     

螺旋天线宽带阻抗匹配技术的研究

介绍了一种用渐变镜像传输线阻抗变换器来实现螺旋天线与50Ω馈线之间的宽带匹配技术.实验结果表明,采用渐变镜像传输线阻抗变换器能在2:1的频带范围内实现 ρ<2.     

Yearly variation in recruitment and its effect on population dynamics inYoldia notabilis (Mollusca: Bivalvia), analyzed using projection matrix model

Summary Long-term variation in recruitment was estimated by constructing projection matrices for a marine bivalve,Yoldia notabilis, at two stations in Otsuchi Bay, northeastern Japan, and the effects of its variation on population dynamics were examined using a simple matrix model. The matrix model was developed from the Leslie matrix, in which the population growth rate λ was expressed as a function of recruitment rater ₀. The equilibrium recruitment rater _s, or the recruitment rate required to maintain population at constant size (λ=1), was expressed by the reciprocal of the reproductive value of a newly recruited individual. The estimates ofr _s for the field population were lower at the shallower station than at the deeper station, reflecting higher survivorship and fecundity. Past recruitment rate estimated both by the field samplings for 3 years and by the back-calculation from the current age structure for over 10 years showed large yearly variation, ranging between 0 and 58.6×10⁻⁴. The estimates were larger thanr _s, and hence, large enough to increase population size (λ>1) only in approximately one-third of the estimated years. This suggests that the population has been maintained by occasional successful recruitment occurring once every few years.     

日本唯美主义文学在中国现代文坛的变异

日本唯美主义文学对中国现代文学产生了深远的影响。然而,中国作家在接受其影响的同时,表现出一种与日本不同的选择性。其一,两者所提倡的“为艺术而艺术”的内涵不同。其二,两者所体现的颓废不同。中国传统文化的根基、中日文化的差异和20世纪二三十年代中国社会现实是产生这种变异现象的原因。     

杜鲁门·卡波特小说的故事空间变化

美国作家杜鲁门·卡波特擅长将叙事策略中的故事空间变化应用于自己的小说中。本文分析了他运用的三种故事空间变化的方式:南方小镇与城市之间的故事空间变化、逃亡式的故事空间变化和旅途式的故事空间变化。以上三种叙事方式不仅仅被视为叙事策略,亦表现出卡波特对美国社会的关注和对现实的深入思考,具有丰富的内蕴。这不失为卡波特研究的一种新思路。     

Monitoring Nonlinear Profiles with Random Effects by Nonparametric Regression

The monitoring of process/product profiles is presently a growing and promising area of research in statistical process control. This study is aimed at developing monitoring schemes for nonlinear profiles with random effects. We utilize the technique of principal components analysis to analyze the covariance structure of the profiles and propose monitoring schemes based on principal component (PC) scores. The number of the PC scores used in constructing control charts is crucial to the detecting power. In the Phase I analysis of historical data, due to the dependency of the PC-scores, we adopt the usual Hotelling T ² chart to check the stability. For Phase II monitoring, we study individual PC-score control charts, a combined chart scheme that combines all the PC-score charts, and a T ² chart. Although an individual PC-score chart may be perfect for monitoring a particular mode of variation, a chart that can detect general shifts, such as the T ² chart and the combined chart scheme, is more feasible in practice. The performances of the schemes under study are evaluated in terms of the average run length.