Improving variance function estimation in semiparametric longitudinal data analysis

We propose an efficient and robust method for variance function estimation in semiparametric longitudinal data analysis. The method utilizes a local log‐linear approximation for the variance function and adopts a generalized estimating equation approach to account for within subject correlations. We show theoretically and empirically that our method outperforms estimators using working independence that ignores the correlations. The Canadian Journal of Statistics 39: 656–670; 2011. © 2011 Statistical Society of Canada     

A Lower Bound for the Wrap-around L2-discrepancy on Combined Designs of Mixed Two- and Three-level Factorials

The objective of this article is to study the issue of employing the uniformity criterion measured by wrap-around L₂-discrepancy to assess the optimal foldover plans. For mixed two- and three-level fractional factorials as the original designs, general foldover plan and combined design under a foldover plan are defined, and the equivalence between any foldover plan and its complementary foldover plan is investigated. A lower bound of wrap-around L₂-discrepancy of combined designs under a general foldover plan is obtained, which can be used as a benchmark for searching optimal foldover plans. Moreover, it also provides a theoretical justification for optimal foldover plans in terms of uniformity criterion.     

Threshold Estimation for Stochastic Processes with Small Noise

Consider a process satisfying a stochastic differential equation with unknown drift parameter, and suppose that discrete observations are given. It is known that a simple least squares estimator (LSE) can be consistent but numerically unstable in the sense of large standard deviations under finite samples when the noise process has jumps. We propose a filter to cut large shocks from data and construct the same LSE from data selected by the filter. The proposed estimator can be asymptotically equivalent to the usual LSE, whose asymptotic distribution strongly depends on the noise process. However, in numerical study, it looked asymptotically normal in an example where filter was chosen suitably, and the noise was a Lévy process. We will try to justify this phenomenon mathematically, under certain restricted assumptions.     

二维奇异非稳态问题有限元解的误差估计

二维奇异问题的有限元方法是实际中经常会遇到的一类问题,对其解决有重要意义.本文讨论二维奇异非稳态问题的有限元方法,证明了弱解的存在唯一性,并给出有限元解的加权L2-模估计.     

On gart's test for interaction of second order

Gart (1972) ottered a Statistic on testing the hypothesis of no second-order interaction in a 2×s×t contingency table. The statistic was tn be used as an asymptotic chi-square with (s-1) (t-1) degrees of freedom. We show that this statistic suiters from the drawback that unless certain side conditions hold, the statistic would reject the null hypothesis with probability approaching one asymptotically even in the null case. Hence the statistic is not strictly valid for the hypothesis for which it was intended.     

单用、叠用、连用——代词“如何”的语法、语义分析

“如何”在现代汉语中的使用率稍低一些。不过,它功能较多,能构成各种不同结构的句式。如“如何＋VP/AP”、“NP＋如何”、“无论/不管＋如何”、“V得＋如何”、“如何如何＋AP/VP”、“NP＋如何如何”、“VP＋如何如何”、“如何如何＋NP”等。论文从单用、叠用、连用角度归纳了“如何”的主要用法,并具体解释了它在不同语境下的具体意义。     

On the Construction of Families of Absolutely Continuous Copulas with Given Restrictions

ABSTRACT

We prove that the standard EWMA mean chart with asymptotic control limits and the EWMA mean chart with time-varying control limits for monitoring mean changes in a normal process with known mean and known variance are ARL-unbiased. Using the results derived we discuss the effects of estimation of the process mean on ARL.     

RIDICULING THE ‘WHITE BREAD ORIGINAL’

The 1994 US Supreme Court decision in Luther Campbell et al. v. Acuff-Rose Music, Inc., written by Justice David Souter, reversed a lower court decision and argued in favor of the rap group 2 Live Crew's playful critique of Roy Orbison's ‘Oh Pretty Woman’ by its function as parody. This essay seeks to contextualize that decision by showing the roots of 2 Live Crew's recording in the practice of ‘covering’ – the re-recording of an existent popular composition – and thus the possibilities for redefining authorship that arose with the advent of digital technology. The compositional techniques allowed by computer programs led to the proliferation of sampling in the hip-hop community, thereby liberating sounds from the original content and reconfiguring them in new songs. The technique allowed a critical, and in some cases adversarial, stance to be taken towards long-standing Western definitions of authorship and ownership. 2 Live Crew added to this rich stew of possibilities the familiar and time-tested genre of parody. Their piece took what one judge referred to as the ‘white bread original’ of the Roy Orbison record and twisted about the implicit point of view with regard to gender and sexuality. Discussion of the legal complications that followed upon the suing of the group by the holder of the copyright in the Orbison song, Acuff-Rose Music, Inc., includes the apparently sanctioned use of the song in the Disney-produced film Pretty Woman as well as the use of other Orbison material in director David Lynch's Blue Velvet. The essay concludes with suggestions as to how the language of Justice Souter's decision allows not only for future parodies but also a reinvigoration of speech, one which calls into question power relationships codified in US copyright statutes.