论解析几何与美

本文用数学美学的观点,具体剖析了解析几何中的美学因素。为在解析几何教学中进行审美教育,提供了有价值的参考。     

数字语言实验室对大学英语教学的影响

对比说明了传统语言实验室及数字语言实验室的特点。数据统计分析的结果显示 ,两个班级在数字语言实验室实践前没有显著区别 ,但在实践后 ,使用数字语言实验室的班级在考试中听力和总成绩都高于使用传统语言实验室的班级。阐明了数字语言实验室在听力教学上的优势及对大学英语教学的影响     

Levels of significance of some two-sample tests wkem observations are from compound normal distributions

This paper presents an investigation of the behavior of the levels of significance of the two-sample t and its related tests and the Mann-Whitney test when the samples are randomly drawn from mixtures of two normal populations (compound normals) and when the sample sizes are small (combined sample sizes ? 15). The use of the compound normal allows for investigation when the underlying populations are unequal, nonnormal, heterogeneous in variances, unimodal or bimodal, possessing smaller than normal kurtosis or containing contamination. The exact distribution of the t and its related tests are given. However, they are not readily amenable to calculations. Most of the numerical results presented were obtained by simulations     

Shannon Entropy and Mutual Information for Multivariate Skew‐Elliptical Distributions

Abstract. The entropy and mutual information index are important concepts developed by Shannon in the context of information theory. They have been widely studied in the case of the multivariate normal distribution. We first extend these tools to the full symmetric class of multivariate elliptical distributions and then to the more flexible families of multivariate skew‐elliptical distributions. We study in detail the cases of the multivariate skew‐normal and skew‐t distributions. We implement our findings to the application of the optimal design of an ozone monitoring station network in Santiago de Chile.     

On the Bumpy Road to the Dominant Mode

Abstract. Maximum likelihood estimation in many classical statistical problems is beset by multimodality. This article explores several variations of deterministic annealing that tend to avoid inferior modes and find the dominant mode. In Bayesian settings, annealing can be tailored to find the dominant mode of the log posterior. Our annealing algorithms involve essentially trivial changes to existing optimization algorithms built on block relaxation or the EM or MM principle. Our examples include estimation with the multivariate t distribution, Gaussian mixture models, latent class analysis, factor analysis, multidimensional scaling and a one‐way random effects model. In the numerical examples explored, the proposed annealing strategies significantly improve the chances for locating the global maximum.     

New critical values for the generalized t and generalized rank-sum procedures

Student's t test as well as Wilcoxon's rank-sum test may be inefficient in situations where treatments bring about changes in both location and scale. In order to rectify this situation, O'Brien (1988, Journal of the American Statistical Association 83, 52-61) has proposed two new statistics, the generalized t and generalized rank-sum procedures, which may be much more powerful than their traditional counterparts in such situations. Recently, however, Blair and Morel (1991, Statistics in Medicine in press) have shown that referencing these new statistics to standard F tables as recommended by O'Brien results in inflations of Type I errors. This paper provides tables of critical values which do not produce such inflations. Use of these new critical values results in Type I error rates near nominal levels for the generalized t statistic and slightly conservative rates for the generalized rank-sum test. In addition to the critical values, some new power results are given for the generalized tests.     

Les raisons de l’action collective : retour sur la mobilisation improbable des salariés d’hypermarchés

For the first time on 1 February 2008, three French labor unions (Force Ouvrière, Confédération Française Démocratique du Travail and Confédération Générale du Travail) called for a nationwide strike in hypermarket chains. Although the unions did not prolong the action on February 2, the wage earners of Hypermag Grand Large in Marseille went on strike for 16 days, demanding a special bonus of € 250, the recruitment of employees forced to work part-time into full-time positions and an increase in the employer's share in meal tickets (from € 3,05 to € 5,00). To explain why this movement occurred at that time and place, these employees’ objective interests and available resources are examined. This pair of concepts (as used in Marxism and then in the thought of Pierre Bourdieu, on the one hand, and, on the other, in utilitarian versions) suggests that labor actions by wage earners holding insecure jobs and having limited resources are improbable. Redefining the concept of the “interest” for a collective action in terms of subjective criteria helps us understand how what used to be tolerable ceases to be so, thus shedding light on the material processes that lead to forming the opinion “It's not fair”.     

PARTIALLY EQUINEIGHBOURED DESIGNS

This paper presents further results on a class of designs called equineighboured designs, ED. These designs are intended for field and related experiments, especially whenever there is evidence that observations in the same block are correlated. An ED has the property that every unordered pair of treatments occurs as nearest neighbours equally frequently at each level. Ipinyomi (1986) has defined and shown that ED are balanced designs when neighbouring observations are correlated. He has also presented ED as a continuation of the development of optimal block designs. An ED would often require many times the number of experimental materials needed for the construction of an ordinary balanced incomplete block, BIB, design for the same number of treatments and block sizes. Thus for a relatively large number of treatments and block sizes the required minimum number of blocks may be excessively large for practical use of ED. In this paper we shall define and examine partially equineighboured designs with n concurrences, PED (n), as alternatives where ED are practically unachievable. Particular attention will be given to designs with smaller numbers of blocks and for which only as little balance as possible may be lost.     

企业生态与企业发展

企业与其生态环境之间存在着相互关系, 通过对企业生态以及由之而引起的企业发展的 讨论和对前后工业社会的企业生态、企业形态及企业管理差异的比较, 使企业管理者认识到不 同的企业发展及管理模式是植根在什么样的企业生态环境之下, 什么样的生态环境适合于什 么企业发展、管理模式、企业生存及其原因.     

公司债务重组的实物期权方法研究

在考虑了公司所得税的情形下研究公司的策略性违约和债务重组问题, 分析表明对于标 准的债务合同, 股东权益最大化的违约时间通常与公司价值最大化的违约时间不一致; 如果不 允许债务重组或债权妥协, 破产清算一般将导致公司价值损失. 但是, 如果允许策略性债务违 约或对绝对优先权原则偏离, 股东权益价值最大化的破产决策将达到与公司价值最大化一致 的结果; 对于较高杠杆或较低杠杆公司, 债务重组具有重要的经济意义, 它可以避免杠杆公司 无效地提早或延迟破产清算.