Estimators for the common principal components model based on reweighting: influence functions and Monte Carlo study

The common principal components model for several groups of multivariate observations is a useful parsimonious model for the scatter structure which assumes equal principal axes but different variances along those axes for each group. Due to the lack of resistance of the classical maximum likelihood estimators for the parameters of this model, several robust estimators have been proposed in the literature: plug-in estimators and projection-pursuit (PP) type estimators. In this paper, we show that it is possible to improve the low efficiency of the projection-pursuit estimators by applying a reweighting step. More precisely, we consider plug-in estimators obtained by plugging a reweighted estimator of the scatter matrices into the maximum likelihood equations defining the principal axes. The weights considered penalize observations with large values of the influence measures defined by Boente et al. (2002). The new estimators are studied in terms of theoretical properties (influence functions and asymptotic variances) and are compared with other existing estimators in a simulation study.     

城市行政级别、数字经济与要素市场扭曲

市场失灵和行政性因素都会导致要素市场扭曲,数字经济可以通过弥补市场失灵改善要素市场扭曲,但要素在高行政级别城市的过度集聚会破坏数字经济改善要素市场扭曲的机制。采用2011—2019年274个城市面板数据的实证分析发现：在高行政级别城市中,数字经济发展对要素市场扭曲具有显著的正向影响,该影响主要源自对劳动要素市场扭曲的加剧,且劳动力集聚程度越高加剧效应越强;在低行政级别城市中,数字经济发展对要素市场扭曲具有显著的负向影响,该影响主要源自对资本要素市场扭曲的改善。对于流动性较强和数字经济渗透度较高的资本要素,数字经济的市场扭曲改善效应较大（在低行政级别城市中）,而要素过度集聚对数字经济改善市场扭曲机制的破坏较弱（在高行政级别城市中）。因此,应以建设全国统一大市场破除要素流动壁垒,以完善城市行政级别体系促进要素（尤其是劳动力）从高级别城市向低级别城市的自由流动,以推进劳动数字化智能化增强数字经济对劳动要素的渗透度,进而有效改善要素市场扭曲,提高资源配置效率。     

Wage inequality in developing countries: South–South trade matters

The relationship between trade liberalization and inequality has received considerable attention in recent years. The major purpose of this study is to present new results on the sources of wage inequalities in manufacturing taking into account South–South (S–S) trade. Globalization has not only lead to increasing North–South (N–S) trade, but it has also changed the direction and composition of trade as more trade is carried out among developing countries. In this study, we find that increasing wage inequality is associated more with the South–South trade liberalization than with the classical trade liberalization with northern countries. A part of this increasing wage inequality due to S–S trade comes from the development of N–S trade relationship in S–S trade that increases wage inequality in middle-income developing countries. This study also seeks to shed some light on the link between the direction of trade and technological change. We explore the fact that S–S trade leads to a technological change biased toward skill-intensive sectors more than N–S trade. This indirect effect increases wage inequality for all developing countries, but it is more important in low-income countries.     

Panel Data Analysis of Regional Differentials in the Registered Voter Turnout Rate and the Expected Benefits of Voting for Minorities

Voter participation rates vary widely across the 50 states. We seek to identify a source of this interstate variation, focusing upon the 2000, 2004, 2008, and 2012 general elections. Of note is that the latter two general elections featured a minority (i.e., African-American) nominee for president from one of the major political parties. Within the context of the rational voter model, we hypothesize that the presence of a minority candidate atop the ticket will boost minorities’ expected net benefits from voting, with the result that minority voter participation will be higher. Based on cross-sectional fixed-effects estimations, we find that states’ voter participation rates were unaffected by the percent of the population that was either African-American or Hispanic for the 2000 and 2004 election cycles, while states’ voter participation rates were positively related to the percent of the population that was either African-American or Hispanic for the 2008 and 2012 election cycles.     

OFDI对中国产业比较优势动态升级的影响

随着经济全球化的发展,国际分工深化为全球价值链分工。从规模效应、结构效应、技术效应3个方面阐释了OFDI对比较优势动态升级的影响机理,利用WIOD数据库测算出1995-2014年中国制造业出口增加值、产业出口优化度EO指数、GVC地位指数并分别表征规模效应、结构效应、技术效应,应用改进后的贸易引力模型和时间序列模型,对3个效应进行检验。研究结果显示,中国企业开展OFDI可以促进比较优势的动态升级,实现价值链攀升。     

国际分散化投资与本土偏好行为——基于QDII对外投资基金的实证分析

本文运用2009年中国8家QDII基金境外组合的周收益历史数据,与基于全球29个股市指数的收益数据构建的国际投资分散化有效前沿进行比较,探讨QDII基金在境外投资过程中是否存在“本土偏好”。研究发现我国QDII基金与国际投资分散化有效边界都存在着不同程度的偏差,反映出较显著的本土偏好的投资行为。本土偏好减弱了国际分散化效果,降低了QDII基金的绩效。资本管制、交易成本和信息不对称是造成本土偏好的主要原因,因此放松资本管制,降低交易成本,降低信息获取成本,加快资本市场开放和合作能够使投资者更好地享受国际分散化投资带来的利益。     

煤炭在洗选及燃烧过程中脱硫方法探析

硫是煤中的有害物质,在燃烧过程中会对环境造成极大的污染。本文重点介绍煤炭在洗选中除硫、煤在燃烧中除硫及煤在燃烧后烟气脱硫的方法。     

数据挖掘技术在企业薪酬设针中的应用研究

现代企业薪酬设计过程中要面对数量众多、关系复杂的信息和数据,而数据挖掘技术在有效处理大量数据方面具有独特的优势。本文以薪酬设计中的数据分析过程为主线,探讨如何应用分类、聚类以及关联规则等数据挖掘技术来分析和处理数据,为薪酬设计提供强有力的决策支持。     

白茅花纤维的形态结构

白茅花纤维是一种细而中空的天然植物纤维,纤维呈圆柱形。长度约为10.0mm,截面近似圆形,细度约为12.3μm。白茅花纤维是一种尚未开发利用的天然植物纤维,但不适合于纺织服装生产,纤维的应用方向还值得研究。     

The behaviour of producer prices: evidence from French PPI micro data

This paper provides some new empirical findings for how French producers set prices. We used the micro data that composes the producer and business-service price indices from 1994 to 2005. First we address how producer prices are collected. Then we present the main characteristics of how producers change their prices: they are modified infrequently and in small amounts. Also, a behavioural heterogeneity across sectors is observed. Business-service prices change less often than industrial producer prices. The data corroborates both time and state-dependent model predictions. Taylor contracts are not unusual, but a firm’s prices will also react to its economic situation. Nevertheless, the most relevant models, to explain producer price rigidity, are time-dependent.

“The fact that some prices are rigid or sticky, while others are variable, has attracted a good deal of comments from economists in recent years” Tucker (1938)

This study was conducted in the context of the Eurosystem Inflation Persistence Network. Data were processed under the responsibility of INSEE in the context of an agreement between INSEE and the Banque de France (20B-21B-E301/R05019/2005).