Mean estimation with data missing at random for functional covariables

In a missing-data setting, we want to estimate the mean of a scalar outcome, based on a sample in which an explanatory variable is observed for every subject while responses are missing by happenstance for some of them. We consider two kinds of estimates of the mean response when the explanatory variable is functional. One is based on the average of the predicted values and the second one is a functional adaptation of the Horvitz–Thompson estimator. We show that the infinite dimensionality of the problem does not affect the rates of convergence by stating that the estimates are root-n consistent, under missing at random (MAR) assumption. These asymptotic features are completed by simulated experiments illustrating the easiness of implementation and the good behaviour on finite sample sizes of the method. This is the first paper emphasizing that the insensitiveness of averaged estimates, well known in multivariate non-parametric statistics, remains true for an infinite-dimensional covariable. In this sense, this work opens the way for various other results of this kind in functional data analysis.     

On the one-sample location hypothesis for mixed bivariate data

We study a hypothesis testing problem involving the location model suggested by Olkin and Tate (1961). Specifically, we derive a likelihood ratio lest of the associated location hypothesis as an alternative to the conventional method of carrying out separate tests for each of the parameters. A small sample Monte Carlo comparison indicates the general superiority of the former in terms of statistical power. We also comment briefly on the properties of the test.     

走出电子游戏的“概念化”误区

目前我国电子游戏业所面临的问题是，市场上充斥着大量模式单一、缺乏内涵的作品，在看似繁荣的游戏事业表象下，隐藏着巨大的发展危机。这一危机带来的不良后果使大批的青少年沉迷于虚幻的网络世界而不能自拔，并且严重阻碍了电子游戏事业自身的发展。对待这些问题，既不能简单的围追堵截，也不能置之不管任由其恶化．而应该以长远的眼光重新去审视这一现象的根本问题所在，寻找有效可行的解决办法。针对某些游戏从业者所持有的错误观点，试图从电子游戏美学角度去诠释制约电子游戏发展的几点观念上的问题。     

高校校内信息资源共建共享的统一性

在信息资源共建共事的过程中，坚持统一性原则就意味着同一所高校范围内学校图书馆和各二级院系资料室．从宏观层面上看。在政策的制定与实施、标准的确立与执行、目标的设置与实现等方面都要具有高度的一致性，这样才能够顺利实现高校校内信息资源的共建共享。     

The power functions of the likelihood ratio tests for a simply ordered trend in normal means

Likelihood ratio tests for the homogeneity of k normal means with the alternative restricted by an increasing trend are considered as well as the likelihood ratio tests of the null hypothesis that the means satisfy the trend. While the work is primarily a survey of results concerning the power functions of these tests, the extensions of some results to the case of not necessarily equal sample sizes are presented. For the case of known or unknown population variances, exact expressions are given for the power functions for k=3,4, and approximations are discussed for larger k. The topics of consistency, bias and monotonicity of the power functions are included. Also, Bartholomew's conjectures concerning minimal and maximal powers are investigated, with results of a new numerical study given.     

Expected Utility Consistent Extensions of Preferences

We consider the problem of extending a (complete) order over a set to its power set. The extension axioms we consider generate orderings over sets according to their expected utilities induced by some assignment of utilities over alternatives and probability distributions over sets. The model we propose gives a general and unified exposition of expected utility consistent extensions whilst it allows to emphasize various subtleties, the effects of which seem to be underestimated – particularly in the literature on strategy-proof social choice correspondences.      

材质的光色影像:媒材与印象派绘画

绘画史是由对媒介的兴趣所支撑着的历史,媒介贯穿着整个绘画历程.艺术史上的每一次变革都伴随着媒材自身的变革,在某些情境下媒材的变革甚至成为了各种艺术潮流、风格演变的先声.印象派正是媒材通过画面的传达和表现,它将人们对古典艺术的形体与线条的崇尚引向对色彩的关注,其作品体现着对色彩的视觉革命所做的贡献与价值.通过物质和精神媒材的演变,印象派绘画映像了社会和时代.     

自适应的Ad hoc MAC协议

为Adhoc网络提出了一种基于模糊逻辑的媒体接入控制层协议。该协议通过在MAC层采用模糊逻辑协调各个相互影响的数据流,为低优先级数据流选择附加退避窗口以减少其自身接入信道概率。通过这种方法,使得高优先级数据流在各种背景流量的条件下,均能够维持较高的端到端吞吐量和较低的端到端接入时延。仿真结果表明,该协议较802.11e协议更好地保护高优先级数据流的端到端时延和吞吐量。