两个并联部件的可修系统的谱分析及其应用

研究了一类两个并联部件的可修系统的动力算子,应用泛函分析方法和C0半群理论,获得了系统算子的较细致的谱分布的结果.据此结果获得了系统解的有限表示和某些可靠性指标.     

Classification and similarity analysis of fundamental frequency patterns in infant spoken language acquisition

Fundamental frequency (F0) patterns, which indicate the vibration frequency of vocal cords, reflect the developmental changes in infant spoken language. In previous studies of developmental psychology, however, F0 patterns were manually classified into subjectively specified categories. Furthermore, since F0 has sequential missing and indicates a mean nonstationarity, classification that employs subsequent partition and conventional discriminant analysis based on stationary and local stationary processes is considered inadequate. Consequently, we propose a classification method based on discriminant analysis of time series data with mean nonstationarity and sequential missing, and a measurement technique for investigating the configuration similarities for classification. Using our proposed procedures, we analyse a longitudinal database of recorded conversations between infants and parents over a five-year period. Various F0 patterns were automatically classified into appropriate pattern groups, and the classification similarities calculated. These similarities gradually decreased with infant019;s monthly age until a large change occurred around 20 months. The results suggest that our proposed methods are useful for analysing large-scale data and can contribute to studies of infant spoken language acquisition.     

On the determinants of public infrastructure spending in Chinese cities: A spatial econometric perspective

In the context of fiscal decentralization, we use cross-sectional data of 242 Chinese cities in 2005 to explore the major factors contributing to the decline of public investment. The main finding is that a city government appears to reduce its own infrastructure spending as a response to the rise of infrastructure spending of its neighboring cities, revealing evidence of positive spillover effects of public infrastructure expenditure. This paper contributes to the existing literature by providing a new perspective for understanding the decline in public investment. In addition, this paper sheds some light on the ongoing debate on the nature of government competition in China and has important implications for policy makers in making fiscal arrangements among government tiers in a decentralized economy.     

简捷·夸张·幽默——从《包氏父子》和《华威先生》看张天翼小说的讽刺艺术个性

张天翼的讽刺小说显示了特独的艺术个性。它是通过戏剧性的片断构思讽刺典型 ,通过夸张和对比手法揭示人物内涵 ,运用了幽默、尖峭的讽刺语言     

均衡——非均衡——反非均衡

文章从演进的方法论入手 ,对均衡———非均衡———反非均衡的发展历史进行评价。在对一般均衡理论评价的同时 ,作为其逻辑后承 ,作者还以科尔内的《反均衡》作为今日经济学发展的一个阶段的开始 ,并结合中国经济发展的现实的非均衡进行分析与评价 ,从而揭示出殊途同归、一致百虑的哲学道理     

直觉不分明化拓扑空间的分离公理

以直觉不分明化邻域系为工具,给出了直觉不分明化拓扑空间的T--0,T1,T2分离性的定义,并研究了它们的一些基本性质.     

ARTIFICIAL STATES

We define artificial states as those in which political borders do not coincide with a division of nationalities desired by the people on the ground. We propose and compute for most countries in the world two measures of the degree to which borders may be artificial. One measures how borders split ethnic groups into two separate adjacent countries. The other measures the straightness of land borders, under the assumption the straight land borders are more likely to be artificial. We then show that these two measures are correlated with several measures of political and economic success.     

Hormesis: A Highly Generalizable and Reproducible Phenomenon With Important Implications for Risk Assessment

From a comprehensive search of the literature, the hormesis phenomenon was found to occur over a wide range of chemicals, taxonomic groups, and endpoints. By use of computer searches and extensive cross-referencing, nearly 3000 potentially relevant articles were identified. Evidence of chemical and radiation hormesis was judged to have occurred in approximately 1000 of these by use of a priori criteria. These criteria included study design features (e.g., number of doses, dose range), dose013;response relationship, statistical analysis, and reproducibility of results. Numerous biological endpoints were assessed, with growth responses the most prevalent, followed by metabolic effects, reproductive responses, longevity, and cancer. Hormetic responses were generally observed to be of limited magnitude with an average maximum stimulation of 30 to 60 percent over that of the controls. This maximum usually occurred 4- to 5-fold below the NOAEL for a particular endpoint. The present analysis suggests that hormesis is a reproducible and generalizable biological phenomenon and is a fundamental component of many, if not most, dose013;response relationships. The relatively infrequent observation of hormesis in the literature is believed to be due primarily to experimental design considerations, especially with respect to the number and range of doses and endpoint selection. Because of regulatory considerations, most toxicologic studies have been carried out at high doses above the low-dose region where the hormesis phenomenon occurs.     

On Approximate Graph Colouring and MAX-k-CUT Algorithms Based on the θ-Function

The problem of colouring a k-colourable graph is well-known to be NP-complete, for k 05.gif" alt="ge" align="MIDDLE" BORDER="0"> 3. The MAX-k-CUT approach to approximate k-colouring is to assign k colours to all of the vertices in polynomial time such that the fraction of `defect edges' (with endpoints of the same colour) is provably small. The best known approximation was obtained by Frieze and Jerrum (1997), using a semidefinite programming (SDP) relaxation which is related to the Lovász 0">-function. In a related work, Karger et al. (1998) devised approximation algorithms for colouring k-colourable graphs exactly in polynomial time with as few colours as possible. They also used an SDP relaxation related to the 0">-function.In this paper we further explore semidefinite programming relaxations where graph colouring is viewed as a satisfiability problem, as considered in De Klerk et al. (2000). We first show that the approximation to the chromatic number suggested in De Klerk et al. (2000) is bounded from above by the Lovász 0">-function. The underlying semidefinite programming relaxation in De Klerk et al. (2000) involves a lifting of the approximation space, which in turn suggests a provably good MAX-k-CUT algorithm. We show that of our algorithm is closely related to that of Frieze and Jerrum; thus we can sharpen their approximation guarantees for MAX-k-CUT for small fixed values of k. For example, if k = 3 we can improve their bound from 0.832718 to 0.836008, and for k = 4 from 0.850301 to 0.857487. We also give a new asymptotic analysis of the Frieze-Jerrum rounding scheme, that provides a unifying proof of the main results of both Frieze and Jerrum (1997) and Karger et al. (1998) for k 0"> 0.     

Cohabitation and Marriage in a Risky World

Different couples are analyzed in presence of income uncertainty and precautionary saving. Married couples have legal restrictions on their relationship that force them to act cooperatively, while cohabitants with limited commitment act non-cooperatively. This makes risk sharing different for different couples; married couples share risk completely, while cohabitants share risk to a lesser extent due to their lack of commitment and cooperation. This makes precautionary savings greater for cohabitants than for married couples. However, cohabitants also tend to undersave to possibly increase assistance from their partner. However, mutual altruism mitigates the inefficiencies and enforces time consistent risk sharing among cohabitants.I am thankful to Jonas Agell, Sophia Grahn-Voorneveld, Peter Kooreman and to Mats Persson for valuable comments on an earlier version. I have also received useful comments from the editor and from two anonymous referees. Generous financial support from the Jan Wallander and Tom Hedelius Foundation and from Knut and Alice Wallenbergs Foundation is gratefully acknowledged.