Knopp曲线逆像研究

研究Knopp曲线的逆像，给出完全的解答：（1）A之逆像数是1；（2）C之逆像数是1；（3）D之逆像数是2；（4）O之逆像数是4；（5）x是直角三角之边，但不是二等分之点，逆像数是1；（6）x是三角形之内部,x是某个直角三角形之边，但不是二等分之点，则逆像数是2；（7）x是三角形之内部，但不属于每个直角三角形之边，则逆像数是1。     

A nonparametric method for asymmetrically extending signal extraction filters

Two important problems in the X‐11 seasonal adjustment methodology are the construction of standard errors and the handling of the boundaries. We adapt the ‘implied model approach’ of Kaiser and Maravall to achieve both objectives in a nonparametric fashion. The frequency response function of an X‐11 linear filter is used, together with the periodogram of the differenced data, to define spectral density estimates for signal and noise. These spectra are then used to define a matrix smoother, which in turn generates an estimate of the signal that is linear in the data. Estimates of the signal are provided at all time points in the sample, and the associated time‐varying signal extraction mean squared errors are a by‐product of the matrix smoother theory. After explaining our method, it is applied to popular nonparametric filters such as the Hodrick–Prescott (HP), the Henderson trend, and ideal low‐pass and band‐pass filters, as well as X‐11 seasonal adjustment, trend, and irregular filters. Finally, we illustrate the method on several time series and provide comparisons with X‐12‐ARIMA seasonal adjustments. Copyright © 2010 John Wiley & Sons, Ltd.     

关于平面简单闭曲线的跨度

给出了关于平面连续统跨度的一个估计不等式，并进一步给出《Ｏｐｅｎ Ｐｒｏｂｅｍｓ ｉｎ Ｔｏｐｏｌｏｇｙ》一书中问题４３３的部分解答。     

Can we agree on an ecological classification of subterranean animals?

That the ties between any obligate subterranean species and the hypogean environment depend on the interplay of a species' own physiological characteristics and all of the ecological characteristics of the adjacent epigean habitat(s), including biotic factors, has been emphasized. The reasons why troglomorphy cannot be included within criteria for classifying cave dwellers have been demonstrated. After a review of historic classifications, standardized definitions of the most widely used terms are proposed. The most easily recognized are four categories which are terminological approximations of the classic Schiner‐Racovitza terminology: (1) troglobiont is a species or population, strictly bound to a hypogean habitat; (2) eutroglophile is an essentially epigean species, but able to maintain a permanent subterranean population; (3) subtroglophile is inclined perpetually or temporarily to inhabit a subterranean habitat but is bound to the surface for some biological functions (e.g. feeding); (4) trogloxene is a species only occurring sporadically underground.     

Ultrastructural redescription of Chordodes moraisi (Carvalho, 1942) and Chordodes straviarskii Carvalho and Feio, 1950, and re‐interpretation of Chordodes gestri Camerano, 1904 and Pseudochordodes griffinii (Camerano, 1898) (Gordiida,Nematomorpha)

The Gordiida species Chordodes moraisi (Carvalho, ) and C. staviarskii Carvalho and Feio, are re‐described using scanning electron microscopy (SEM). Chordodes moraisi is characterized by four areole types, two of which correspond to tubercle areoles, the crown areoles appear as single structures and occur on both sides along the ventral midline. Chordodes staviarskii is characterized by a polymorphism of crowned areoles which appear as two types with distinct distribution patterns. Two species, Chordodes gestri Camerano, and Pseudochordodes griffinii (Camerano, ), are synonymized with Neochordodes occidentalis (Montgomery, 1898) and Chordodes peraccae (Camerano, 1894).     

Do caterpillars of Dryas iulia alcionea (Lepidoptera,Nymphalidae) show evidence of adaptive behaviour to avoid predation by ants?

Plants bearing extrafloral nectaries can attract wasps, bugs, and mainly ants. Ants can defend plants against herbivores by treating the plant as an extension of their own territory. We evaluated the efficiency of resting sites built by Dryas iulia alcionea larvae as protection against ant predation on their host plant Passiflora suberosa. The results showed that ants on P. suberosa have significant influence on the survival of D. iulia caterpillars. The use and construction of resting sites was recorded through the fourth larval stadium. A strong inverse relationship between the number of resting sites constructed per larva and the developmental stage of the larvae was observed. Additional results suggest that the efficacy of resting sites against cursorial predators decreases with larval development. The behaviour of constructing resting sites probably evolved by natural selection. It is likely that this behaviour was important for the ancestral lineage that gave origin to Heliconiinae genera Dryas, Dryadula and Phylaethria.     

A Meta‐learning Framework for Bankruptcy Prediction

The implication of corporate bankruptcy prediction is important to financial institutions when making lending decisions. In related studies, many bankruptcy prediction models have been developed based on some machine‐learning techniques. This paper presents a meta‐learning framework, which is composed of two‐level classifiers for bankruptcy prediction. The first‐level multiple classifiers perform the data reduction task by filtering out unrepresentative training data. Then, the outputs of the first‐level classifiers are utilized to create the second‐level single (meta) classifier. The experiments are based on five related datasets and the results show that the proposed meta‐learning framework provides higher prediction accuracy rates and lower type I/II errors when compared with the stacked generalization classifier and other three widely developed baselines, such as neural networks, decision trees, and logistic regression. Copyright © 2011 John Wiley & Sons, Ltd.     

强F_1连通的新特征

在LF-拓扑空间中,文[2,3]引进了强F1连通的概念,并研究了其基本性质.本文利用层次闭集和层次开集给出了强F1连通的若干新特征.     

关于闭集是凸集的几个等价充分条件

给出一个闭集A包含E^m是凸集的几个等价充分条件，并对结果进行证明。