Truncated sequential change-point detection based on renewal counting processes II

The standard approach in change-point theory is to base the statistical analysis on a sample of fixed size. Alternatively, one observes some random phenomenon sequentially and takes action as soon as one observes some statistically significant deviation from the “normal” behaviour. The present paper is a continuation of Gut and Steinebach [2002. Truncated sequential change-point detection based on renewal counting processes. Scand. J. Statist. 29, 693–719] the main point being that here we look in more detail into the behaviour of the relevant stopping times, in particular the time it takes from the actual change-point until the change is detected, more precisely, we prove asymptotics for stopping times under alternatives.     

Family income at the bottom and at the top: Income sources and family characteristics

Attention has recently been focused on wealth as a source of long-term economic security and on wealth ownership as a crucial aspect of the racial economic divisions in the United States. This literature, however has been concerned primarily with the wealth gap between poor and middle-class families, and between the white and black middle class. In this paper, we investigate the incomes of families at the top and bottom of the family income distribution. We examine the sources of income and the demographic characteristics of these high-income and low-income families using family level data from the 1988 to 2003 Current Population Surveys.     

弱光对不同品种苋菜叶片抗氧化物质的影响

以绿叶苋和花红苋为材料,研究了2种苋菜叶片在弱光逆境下部分抗氧化物质的变化.结果表明：弱光胁迫下,2种苋菜叶片总酚含量相近;绿叶苋叶中类黄酮和类胡萝卜素的生成量均大于花红苋,苋菜红素含量明显下降;两者总抗氧化能力均随弱光处理而下降,但花红苋的降幅较绿叶苋小且维持在较高水平,恢复自然光照有利于2种苋菜总抗氧化能力的回升.     

Estimation and selection procedures in regression: An L1 approach

The authors consider the problem of estimating a regression function go involving several variables by the closest functional element of a prescribed class _G that is closest to it in the L₁ norm. They propose a new estimator ? based on independent observations and give explicit finite sample bounds for the L₁distance between ?g and go. They apply their estimation procedure to the problem of selecting the smoothing parameter in nonparametric regression.     

Demographic change, endogenous labor supply and the political feasibility of pension reform

Options for reforming unfunded public pension schemes that are now being discussed all share the feature that the burden induced by demographic change would be shifted towards presently living and away from unborn generations. Existing models of the political economy of pension reform can not explain why such reform options are being discussed at all. We present an alternative model in which the possibility of evasion of workers from payment of social security taxes is taken into account by modelling a labor supply function. It turns out that the burden of demographic change may fall completely or at least predominantly on the pensioners. Thus this type of model can much better explain recent trends in legislature on unfunded public pension systems in industrial democracies. Received: 7 January 1999/Accepted: 20 December 1999     

几种贝类组织细胞培养的研究

贝类组织细胞培养研究始于上世纪六十年代。相对于建系技术已很成熟的哺乳动物和昆虫,贝类细胞培养的发展一直处于落后状态。现综述几种作为重要海产养殖品种的贝类组织细胞培养的研究,并总结目前在该领域面临的问题,以期为摸索贝类细胞培养条件、进一步建立起细胞系提供参考。     

Bootstrap versus traditional hypothesis testing procedures for coefficients in least absolute value regression

Several approaches to hypothesis testing for coefficients in least absolute value regression are compared using a Monte Carlo simulation: likelihood ratio test, Lagrange multiplier test, and three versions of the bootstrap hypothesis test. Factors considered that might influence test performance include the disturbance distribution, the type of independent variable, and the sample size. Overall, the likelihood ratio and the bootstrap tests perform best, with the likelihood ratio test being marginally more powerful. Least absolute value tests are also compared to the standard t test and three versions of the bootstrapped t test for least squares regression.     

长沙市民世博旅游行为初探

世界博览会是一种重要的全球性展会,研究城市居民的世博旅游行为,有助于更好地开发会展旅游市场。通过问卷调查,分析了长沙市民对上海世博会的出游行为。结果显示,长沙市民有着较强烈进行世博旅游的意愿,没有能够实现出游意愿的主要原因是时间和经济条件的限制。长沙市的世博旅游者去上海的交通工具主要为动车和飞机,出游方式以自助为主,住宿方式表现为多样化,对世博的服务、卫生、增长知识、园内参观以及整个世博旅游都有着较高的评价。同时,在世博结束后,长沙市民对保留下来的中国馆和湖南馆仍然有着强烈的参观意愿。     

论内部审计的几个问题

本文对我国内部审计的地位、职能和作用作了较为全面的分析 ,提出了内部审计在五个不同层次上的独特地位 ,评述和总结出了内部审计具有的三大职能及具体表现 ,并对内部审计的作用从一般经济条件和特定经济条件两个方面进行了新的分析。