我国基金风格资产收益长记忆性分析——基于修正R/S方法的研究

证券市场是个典型的非线性复杂系统。本文运用修正R/S分析法对我国基金风格资产收益单一分形的基本统计特征进行检验,并与经典R/S方法进行对比分析。研究结果表明:在日、周、月等三种时间标度下Hurst指数均显著大于0.5,表现为持久相关性特征,说明股市风格具有长记忆性;从经典R/S分析结果看,我国股市风格具有显著的分形结构特征,风格资产指数收益率序列具有长记忆性,不同风格资产的业绩具有不同的周期性。     

大型研发企业的研发投入分析——基于全球前2000家企业研发投入数据

利用2006年全球研发投入居前2000位的企业数据,考察了这些企业研发投入的一些基本特征,如产业分布、国家分布,以及研发的集中度,并探讨了企业研发投入与企业规模之间的关系。研究结论是：研发具有产业异质性;研发在一些国家集中;企业研发的总量水平、研发比率、研发增长率与企业规模具有非线性关系．中型企业具有较高的研发投入量,而小型企业与大型企业具有较高有研发投入比,以及研发增长率。     

Brain drain or brain bank? The impact of skilled emigration on poor-country innovation

The development prospects of a poor country or region depend in part on its capacity for innovation. In turn, the productivity of its innovators, whom are often concentrated around urban centers, depends on their access to technological knowledge. The emigration of highly skilled individuals weakens local knowledge networks (brain drain) but may also help remaining innovators access valuable knowledge accumulated abroad (brain bank). We develop a model in which the size of the optimal innovator Diaspora depends on the competing strengths of co-location and Diaspora effects for accessing knowledge. Then, using patent citation data associated with inventions from India, we estimate the key co-location and Diaspora parameters. The net effect of innovator emigration is to harm domestic knowledge access, on average. However, knowledge access conferred by the Diaspora is particularly valuable in the production of India’s most important inventions as measured by citations received. Thus, our findings imply that the optimal emigration level may depend, at least partly, on the relative value resulting from the most cited compared to average inventions.     

Is the division of labour limited by the extent of the market? Evidence from French cities

This paper provides supportive evidence to the notion that the division of labour is limited by the extent of the (local) market. We first propose a theoretical model. Its main prediction is that scarce specialists occupations are over-represented in large cities. Using census data for French cities, we find strong empirical support for this prediction.     

Spatial concentration and plant-level productivity in France

This paper analyzes empirically the effect of spatial agglomeration of activities on plant-level productivity, using French firm and plant-level data from 1996 to 2004. We exploit short-run variations of variables by making use of GMM estimation. This allows us to control for endogeneity biases that the estimation of agglomeration economies typically encounters. This means that our paper focuses on a subset of agglomeration economies, the short-run ones. Our results show that French plants benefit from localization economies, but we find very little - if any - evidence of urbanization economies. We also show that those localization benefits are relatively well internalized by firms in their location choice: we find very little difference between the geography that would maximize productivity gains in the short-run and the geography actually observed.     

On the equivalence of location choice models: Conditional logit, nested logit and Poisson

It is well understood that the two most popular empirical models of location choice - conditional logit and Poisson - return identical coefficient estimates when the regressors are not individual specific. We show that these two models differ starkly in terms of their implied predictions. The conditional logit model represents a zero-sum world, in which one region’s gain is the other regions’ loss. In contrast, the Poisson model implies a positive-sum economy, in which one region’s gain is no other region’s loss. We also show that all intermediate cases can be represented as a nested logit model with a single outside option. The nested logit turns out to be a linear combination of the conditional logit and Poisson models. Conditional logit and Poisson elasticities mark the polar cases and can therefore serve as boundary values in applied research.     

民国时期(1927-1937年)城市规划机制探析

民国时期的城市规划法律文化有值得当今借鉴的因素,文章全面回顾民国前期城市规划机制的发展脉络,对1927年到1937年民国时期国家层面的城市规划主体、规划法律制度进行了探讨.在此基础上,初步总结了国民政府和伪满洲国的城市规划主体的主要构成和法律制度的主要内容,以及有益启示和教训.     

Regional Grants: Are They Worth It?*

Regional grants have recently come under scrutiny and are controversial. Some estimates put the employment effect of these grants at no more than 6,000 jobs in the first half of the 1990s, against expenditure of £500 million. Other aspects of the grants are questioned, such as their ability to attract foreign direct investment and their effect on productivity. This paper reviews these issues, focusing on the recent evidence for the Regional Selective Assistance scheme. It describes the nature and difficulties involved in policy evaluation, and finds that differences over the employment effect of the grants result from possible biases induced by the evaluation methodology and from differences in the job measure used. Overall, the paper argues that the regional grants are cost‐effective in employment terms, but that expenditure is small relative to the scale of the problem, so that an expansion of the grants may be desirable.     

GMM and 2SLS estimation of mixed regressive,spatial autoregressive models

The GMM method and the classical 2SLS method are considered for the estimation of mixed regressive, spatial autoregressive models. These methods have computational advantage over the conventional maximum likelihood method. The proposed GMM estimators are shown to be consistent and asymptotically normal. Within certain classes of GMM estimators, best ones are derived. The proposed GMM estimators improve upon the 2SLS estimators and are applicable even if all regressors are irrelevant. A best GMM estimator may have the same limiting distribution as the ML estimator (with normal disturbances).     

Big Players in Slovenia

The subjectivism of Austrian economics helps to explain the statistical fact of long memory in asset prices. The theory of Big Players is an Austrian approach to understanding the effects of discretionary policymaking in markets. It leads to implications that can be tested with statistics. In particular, Big Players induce herding and, thereby, an increase of persistence in asset prices. A recent episode in Slovenian monetary theory provides a case study. This case study adds to a set of similar studies, all tending to support the theory of Big Players.