An invariance principle forU-statistics in simple random sampling without replacement

Summary Supplementing the well-known invariance principle forU-statistics based on i.i.d. observations (Miller and Sen 1972) we establish an invariance principle forU-statistics in case of simple random sampling from a sequence of finite populations. This generalizes the asymptotic normality-result of Nandi and Sen (1963), and permits e.g. to prove asymptotic normality ofU-statistics in the presence of random non-response.     

Social Distance,Respondent Cooperation and Item Nonresponse in Sex Survey

This paper examines the ways in which the number of item nonresponses is determined by social distance and/or interview rapport, with a focus on responses of “refusal” and “don’t know”, implying the respondent’s lack of willingness and ability to provide substantive responses to sensitive questions. The data analyzed were from 39 self- administered questions concerning sexual attitudes and behaviors in the 2002 Taiwan Social Change Survey for module “Family and Changing Gender Role”. Poisson Regression in 2-level Hierarchical Linear Model was employed to enhance the accuracy of the analysis of the accumulation of “don’t know” and “refusal” responses. The results showed that respondent cooperation significantly decreased the number of both “don’t know” and “refusal” replies. The decrease was not conditioned by any kind of social distance. Age and education distances have respectively negative and positive effect on the number of “don’t know” and “refusal” answers. The married–married interview produced more “don’t know” and “refusal” than other paired interview types. The larger the ethnicity distance is, the more “refusal” appears. The substantial findings imply that the effects of social-distance and rapport (respondent cooperation) on the number of item nonresponses deserve more attention in research on survey methodology. The divergent findings on gender-distance effect and marital-status effect, however, call for replication studies in the future.     

Differential levels of disclosure and the earnings-return association: evidence from foreign registrants in the United States

Foreign companies listing on U.S. exchanges are required to report financial information under U.S. GAAP on form 20-F using either Item 17 or Item 18 disclosure rules. These two disclosure rules differ in that Item 17 allows many exemptions from U.S. GAAP, while Item 18 requires disclosure of all financial information in accordance with U.S. GAAP. This study examines the differential earnings-return association between Item 17 and Item 18 filers.We find significantly higher earnings-return associations for Item 18 filers than for Item 17 filers. While the earnings-return association of Item 18 foreign firms is not different from that of matched U.S. firms (which fundamentally use Item 18 rules), the earnings-return association of Item 17 foreign firms is significantly lower than that of matched U.S. firms. Overall, the results are consistent with the idea that higher levels of disclosure may be related to lower discount rates and higher earnings response coefficients (ERCs).     

通用航空飞机融资租赁风险管理研究——以A通航融资租赁公司为例

近年来,为助力通用航空业务发展诞生了一批专业的通用航空飞机融资租赁企业,并累计为数千架次通用航空飞机提供了融资租赁服务。本文基于弥补行业健康良性发展理论,着重就通用航空飞机租赁业务中租赁物风险、承租人和出租人各自将承担的风险以及如何管理各方风险进行研究。研究表明通用航空融资租赁业务在租赁物飞机选择上应首选市场保有量大的机型,并始终确保飞机处于适航状态,承租人应首选有着丰富通航飞机运营经验的企业,租赁方案除平衡风险和收益外,明晰租赁物所有权至为重要。本文丰富了通用航空融资租赁业务相关文献,为行业实践工作提供了可行操作指南。     

Quality of local equilibria in discrete exchange economies

This paper defines the notion of a local equilibrium of quality $(r,s)$, $0\le r,s$, in a discrete exchange economy: a partial allocation and item prices that guarantee certain stability properties parametrized by the numbers $r$ and $s$. The quality $(r,s)$ measures the fit between the allocation and the prices: the larger $r$ and $s$ the closer the fit. For $r,s\le 1$ this notion provides a graceful degradation for the conditional equilibria of Fu, Kleinberg and Lavi (2012) which are exactly the local equilibria of quality $(1,1)$. For $1<r,s$ the local equilibria of quality $(r,s)$ are more stable than conditional equilibria. Any local equilibrium of quality $(r,s)$ provides, without any assumption on the type of the agents’ valuations, an allocation whose value is at least $\frac{rs}{1+rs}$ the optimal fractional allocation. In any economy in which all agents’ valuations are $a$-submodular, i.e., exhibit complementarity bounded by $a\ge 1$, there is a local equilibrium of quality $(\frac{1}{a},\frac{1}{a})$. In such an economy any greedy allocation provides a local equilibrium of quality $(1,\frac{1}{a})$. Walrasian equilibria are not amenable to such graceful degradation.     

FP-Growth算法在电子商务中的应用

针对电子商务推荐销售的需求和FP-Growth算法不产生候选集的特性,提出利用FP-Growth算法,运用VC++程序开发工具,对某一电商卖家的数据进行频繁项集挖掘,针对挖掘得到的频繁K项集,指导卖家如何组合商品销售。试验结果表明利用FP-Growth算法在电商组合销售中是有效的。     

Taking ‘Don’t Knows’ as Valid Responses: A Multiple Complete Random Imputation of Missing Data

Incomplete data is a common problem of survey research. Recent work on multiple imputation techniques has increased analysts’ awareness of the biasing effects of missing data and has also provided a convenient solution. Imputation methods replace non-response with estimates of the unobserved scores. In many instances, however, non-response to a stimulus does not result from measurement problems that inhibit accurate surveying of empirical reality, but from the inapplicability of the survey question. In such cases, existing imputation techniques replace valid non-response with counterfactual estimates of a situation in which the stimulus is applicable to all respondents. This paper suggests an alternative imputation procedure for incomplete data for which no true score exists: multiple complete random imputation, which overcomes the biasing effects of missing data and allows analysts to model respondents’ valid ‘I don’t know’ answers.     

能力验证均匀性检验的两种统计分析方法比较及结果合理性判断

分析了0.3？σ方法与F检验两种统计方法各自的优缺点和适用范围。0.3？σ方法以能力统计量作为评价的依据,F检验使用正态分布下的显著性偏差作为临界条件。因此,在使用0.3？σ方法时,应关注样品的不均匀性和方法的精密度;在使用F检验时,应预先进行数据正态性的验证。