Portmerion, Proportion and Perspective

The holiday village of Portmerion was created by Bertram Clough Williams-Ellis (1883 1978) over a period of fifty-one years, starting in 1926. It was grade II listed in 1971. However, Portmerion has become a part of western popular culture rather than of mainstream architectural history. Its use as the setting for the cult 1967 television series “The Prisoner” ensures continued worldwide interest and a constant stream of visitors. Williams Ellis’ design methods were empirical, initial designs being adjusted by eye on site in close collaboration with trusted builders. This paper analyses the development of Portmerion as a gesamtkunstwerk; considering the experience of movement through the village as a dynamic composition of shifting vistas, focussing the visitor on a series of constructed views. Through this analysis, Portmerion is revealed as both a manifestation of the architecture of pleasure and an exercise in the pleasure of architecture

The Proportion of Weierstrass Semigroups

We solve a problem of Komeda concerning the proportion of numerical semigroups which do not satisfy Buchweitz' necessary criterion for a semigroup to occur as the Weierstrass semigroup of a point on an algebraic curve. We also show that the family of semigroups known to be Weierstrass semigroups using a result of Eisenbud and Harris, has zero density in the set of all semigroups. In the process, we prove several more general results about the structure of a typical numerical semigroup.Comment: 15 pages. Corrected typos, some minors mathematical changes, added some discussion. To appear in J. Algebr

Variance estimation for a low-income proportion

Proportions below a given fraction of a quantile of an income distribution are often estimated from survey data in poverty comparisons. We consider the estimation of the variance of such a proportion, estimated from Family Expenditure Survey data. We show how a linearization method of variance estimation may be applied to this proportion, allowing for the effects of both a complex sampling design and weighting by a raking method to population controls. We show that, for 1998-99 data, the estimated variances are always increased when allowance is made for the design and raking weights, the principal effect arising from the design. We also study the properties of a simplified variance estimator and discuss extensions to a wider class of poverty measures

Proportion Regulation in Globally Coupled Nonlinear Systems

As a model of proportion regulation in differentiation process of biological system, globally coupled activator-inhibitor systems are studied. Formation and destabilization of one and two cluster state are predicted analytically. Numerical simulations show that the proportion of units of clusters is chosen within a finite range and it is selected depend on the initial condition.Comment: 11 pages (revtex format) and 5 figures (PostScript)

Proportion in school mathematics textbooks: A comparative study

This paper analyses how proportion is introduced and developed in selected mathematics textbooks for middle school students of Portugal, Spain, Brazil, and USA. The analysis focuses on the nature of the approach and on the cognitive demand, structure, and context of the tasks. The results show that the textbooks tend to present tasks at an intermediate level of cognitive demand and with a closed structure. Nonmathematical contexts predominate in three of the four textbooks. However, there are marked differences in the way textbooks approach the conceptual and procedural aspects of proportion. The way the students are addressed also varies, ranging from a questioning/problem solving style, to an explaining/practicing style, each of these styles supporting a rather different kind of activity.Este artigo analisa como proporção é introduzida e desenvolvida nos livros didáticos matemática para alunos do ensino médio (Ensino Fundamental II) em Portugal, Espanha, Brasil e EUA. A análise incide sobre a natureza da abordagem e na demanda cognitiva, estrutura e contexto das tarefas. Os resultados mostram que os livros didáticos tendem a apresentar as tarefas em um nível intermediário de demanda cognitiva e com uma estrutura fechada. Contextos não-matemáticos predominam em três dos quatro livros didáticos analisados. No entanto, há diferenças marcantes no modo como os livros abordam os aspectos conceituais e procedimentais de proporção. A forma didática de tratar o assunto também varia, indo de um estilo de questionamento / resolução de problemas, a um modo explicativo/prático; cada um deles ampara-se em um tipo diferente de atividade

On stepdown control of the false discovery proportion

Consider the problem of testing multiple null hypotheses. A classical approach to dealing with the multiplicity problem is to restrict attention to procedures that control the familywise error rate ($FWER$), the probability of even one false rejection. However, if $s$ is large, control of the $FWER$ is so stringent that the ability of a procedure which controls the $FWER$ to detect false null hypotheses is limited. Consequently, it is desirable to consider other measures of error control. We will consider methods based on control of the false discovery proportion ($FDP$) defined by the number of false rejections divided by the total number of rejections (defined to be 0 if there are no rejections). The false discovery rate proposed by Benjamini and Hochberg (1995) controls $E(FDP)$. Here, we construct methods such that, for any $\gamma$ and $\alpha$, $P\{FDP>\gamma \}\le \alpha$. Based on $p$-values of individual tests, we consider stepdown procedures that control the $FDP$, without imposing dependence assumptions on the joint distribution of the $p$-values. A greatly improved version of a method given in Lehmann and Romano \citer10 is derived and generalized to provide a means by which any sequence of nondecreasing constants can be rescaled to ensure control of the $FDP$. We also provide a stepdown procedure that controls the $FDR$ under a dependence assumption.Comment: Published at http://dx.doi.org/10.1214/074921706000000383 in the IMS Lecture Notes--Monograph Series (http://www.imstat.org/publications/lecnotes.htm) by the Institute of Mathematical Statistics (http://www.imstat.org