基于电子市场中介的交易风险控制

电子市场中介实施控制可以有效地降低电子商务中的交易风险.在讨论客观风险、估计风险、交易者风险偏好及风险控制相互之间关系的基础上,设计了电子市场中介的交易风险控制机制,构建了控制水平选择的决策模型,讨论了模型最优解的存在性,进而分析了交易者平均风险偏好一定和变化情况下的最优控制策略.分析结果有助于电子市场中介的交易风险控制决策.     

Hypothesis Testing of Hazard Ratio Parameters in Marginal Models for Multivariate Failure Time Data

Marginal hazard models for multivariate failure time data have been studied extensively in recent literature. However, standard hypothesis test statistics based on the likelihood method are not exactly appropriate for this kind of model. In this paper, extensions of the three commonly used likelihood hypothesis test statistics are discussed. Generalized Wald, generalized score and generalized likelihood ratio tests for hazard ratio parameters in a marginal hazard model for multivariate failure time data are proposed and their asymptotic distributions examined. The finite sample properties of these statistics are studied through simulations. The proposed method is applied to data from Busselton Population Health Surveys.     

HFC－134a水平管内流动沸腾换热研究的进展

在分析国外有关文献的基础上，对ＨＦＣ－１３４ａ水平管内流动沸腾换热研究的现状和已取得的成果进行了综述，指出了该领域进一步研究的方向．     

Marginal Means/Rates Models for Multiple Type Recurrent Event Data

Recurrent events are frequently observed in biomedical studies, and often more than one type of event is of interest. Follow-up time may be censored due to loss to follow-up or administrative censoring. We propose a class of semi-parametric marginal means/rates models, with a general relative risk form, for assessing the effect of covariates on the censored event processes of interest. We formulate estimating equations for the model parameters, and examine asymptotic properties of the parameter estimators. Finite sample properties of the regression coefficients are examined through simulations. The proposed methods are applied to a retrospective cohort study of risk factors for preschool asthma.     

经济学和经济哲学的智慧

经济学是关于经济生活的智慧 ,而经济哲学则是对经济学智慧的进一步抽象 ,是更高一层的智慧。经济哲学应当深入经济学研究中探求方法论问题 ,并要求有更多、更广的“原创性”。     

Perfect simulation for correlated Poisson random variables conditioned to be positive

In this paper we present a perfect simulation method for obtaining perfect samples from collections of correlated Poisson random variables conditioned to be positive. We show how to use this method to produce a perfect sample from a Boolean model conditioned to cover a set of points: in W.S. Kendall and E. Thönnes (Pattern Recognition 32(9): 1569–1586, 1999), this special case was treated in a more complicated way. The method is applied to several simple examples where exact calculations can be made, so as to check correctness of the program using ²-tests, and some small-scale experiments are carried out to explore the behaviour of the conditioned Boolean model.     

计算机实验教学中的“人本化”探讨

本文针对目前计算机实验教学中所面临的学生能动性方面的薄弱环节,从"人本化"的理念角度,分析其产生的根源及影响因素,探讨计算机实验教学的"人本化"这一新课题.     

Some results on generalized ageing classes

In this paper we provide new results about generalized ageing classes on the excess lifetime of a renewal process. We also obtain some characterizations of generalized ageing classes by means of the residual life at random time.     

论西塞罗的历史观

西塞罗在《论演说家》（De Oratore）中阐述了历史的特性、历史的目的以及应该怎样写作历史。他对这一问题的看法没有超出修辞学家的认识范畴，认为历史写作应该强调两个方面，即历史的“真实”和文学的加工，“真实”在他那里其实是“公正”，而文学的渲染则体现了历史应该具有的教化功能。他的历史理论和方法对后来罗马史学的发展产生了深远的影响。     

一种简单的过流过压保护电路

详细介绍了一种实用的过流过压保护电路及工作原理 ,该电路具有可靠性高、反应快等特点