Modelling exchange of probabilistic opinions

Summary. This paper studies how communication or exchange of opinions influences correlation of beliefs. The paper focuses on a situation in which agents communicate with each other infinitely many times without observing data. It is an extension to the ‘Expert Problem’ in Bayesian theory, where the informational flow is asymmetric. Moreover, this paper generalizes the existing literature of communication that employs the common prior assumption (CPA) by allowing for heterogeneous beliefs. Some basic convergence results are shown in contrast with the results obtained under the CPA. Furthermore, several economic implications of the basic results are provided. Received: August 27, 2001; revised version: April 16, 2002 RID="*" ID="*" The results presented in this paper are taken from my Ph.D. thesis at Stanford University. I gratefully acknowledge the inspiration obtained from innumerable discussions with Mordecai Kurz about this subject. Also, I appreciate comments from Kenneth J. Arrow, Peter J. Hammond, Maurizio Motolese, Carsten K. Nielsen, Ho-Mou Wu and the anonymous referee.     

基于Oracle9i的物流空间信息数据库的一种设计与实现方法

通过Oracle Spatial组件的支持，我们可以在物流系统中实现时空间信息的解决方案。本文探讨了物流空间信息需求，介绍了用Oracle spatial建立物流空间数据库的方法，Oracle可以作为物流空间信息管理分析的一个较好的解决方案。     

Existence of a competitive equilibrium in a one sector growth model with heterogeneous agents and irreversible investment

Summary. We prove existence of a competitive equilibrium in a version of a Ramsey (one sector) model in which agents are heterogeneous and gross investment is constrained to be non negative. We do so by converting the infinite-dimensional fixed point problem stated in terms of prices and commodities into a finite-dimensional Negishi problem involving individual weights in a social value function. This method allows us to obtain detailed results concerning the properties of competitive equilibria. Because of the simplicity of the techniques utilized our approach is amenable to be adapted by practitioners in analogous problems often studied in macroeconomics. Received: September 13, 2001; revised version: December 9, 2002 RID="*" ID="*" We are grateful to Tapan Mitra for pointing out errors as well as making very valuable suggestions. Thanks are due to Raouf Boucekkine and Jorge Duran for additional helpful discussions. We also thank an anonymous referee for his/her helpful comments. The second author acknowledges the financial support of the Belgian Ministry of Scientific Research (Grant ARC 99/04-235 “Growth and incentive design”) and of the Belgian Federal Goverment (Grant PAI P5/10, “Equilibrium theory and optimization for public policy and industry regulation”). Correspondence to: C. Le Van     

A novel cluster HAR-type model for forecasting realized volatility

This paper proposes a cluster HAR-type model that adopts the hierarchical clustering technique to form the cascade of heterogeneous volatility components. In contrast to the conventional HAR-type models, the proposed cluster models are based on the relevant lagged volatilities selected by the cluster group Lasso. Our simulation evidence suggests that the cluster group Lasso dominates other alternatives in terms of variable screening and that the cluster HAR serves as the top performer in forecasting the future realized volatility. The forecasting superiority of the cluster models are also demonstrated in an empirical application where the highest forecasting accuracy tends to be achieved by separating the jumps from the continuous sample path volatility process.     

The effect of heterogeneous beliefs on mergers and acquisitions

This article investigates the effect of heterogeneous beliefs on firms’ mergers and acquisitions (M&A) decisions. Using data of China’s financial market, which is featured with great heterogeneity of belief, we find that heterogeneous beliefs are positively associated with the occurrence of M&A transactions, and firms with greater heterogeneous beliefs are more likely to pay the transactions with stock. Moreover, we show that government intervention, measured by state ownership, weakens the effect of heterogeneous beliefs on firms’ M&A decisions.     

Macroeconomic implications of modeling the Internal Revenue Code in a heterogeneous-agent framework

Tax policy analysis in heterogeneous-agent models typically involves the use of smooth tax functions to approximate complex present tax law and proposed reforms. In this paper, we explore the extent to which the tax detail omitted under this conventional approach has macroeconomic implications relevant for policy analysis. To do this, we develop an alternative approach by embedding an internal tax calculator into a large-scale overlapping generations model that, while conditioning on idiosyncratic household characteristics, explicitly models key provisions in the Internal Revenue Code applied to labor income. We find that for a debt-constant steady state analysis of a given tax policy change, both approaches generate similar policy-induced patterns of macroeconomic activity despite variation in the underlying patterns of household tax-preferred consumption and labor supply behavior. However, this variation in underlying behavior is associated with significant quantitative and qualitative differences in macroeconomic aggregates along a debt-financed transition path immediately following a policy change. Consequentially, although the use of unconditional smooth tax functions may be a reasonable modeling simplification for steady state analysis of tax policy, caution should be taken for their use in transition path analysis within heterogeneous-agent models.     

Capital accumulation through studying abroad and return migration

This paper examines the interplays among studying abroad, return migration and capital accumulation, in a dynamic general equilibrium model featuring heterogeneous ability. Households invest in education and make two migration decisions: whether to study abroad and subsequently whether to return home. The model predicts that the highest, middle and lowest-ability people choose respectively permanent migration, return migration and no migration. More interestingly, we find a novel migration cycle: returnees bring back learned-knowledge and over time, capital accumulates, attracting more return migration. Further, the usual “brain drain” in the literature can be turned into “brain gain”, by providing a subsidy to studying abroad and returning home.     

Portfolio constraints,differences in beliefs and bubbles

I propose an arbitrage-based theory of bubbles in economies with general portfolio constraints and differences in beliefs. I find that, in general, bubbles cannot exist unless the constraints restrict the demand for credit sufficiently to induce low interest rates. Speculation due to heterogeneous beliefs does not cause bubbles. Ruling out bubbles under asymmetric information requires stronger assumptions: the presence of some uninformed agents and mild portfolio restrictions (debt or borrowing constraints), or alternatively, the existence of some impatient and fully informed agents.     

异质性企业、结构转型与稳定出口

通过构建异质性企业、结构转型和出口增长的二元边际理论模型,本文认为转型国家出口增长主要沿集约边际实现的原因与其农业剩余劳动力有关,农业剩余劳动力越多,出口增长的集约边际越大、扩展边际越小。利用Tobit模型对1995-2009年中国出口到123个国家的HS-6位码贸易数据进行实证分析,在控制其他影响因素的前提下,我国农业剩余劳动力非农转移显著正向影响出口增长集约边际、负向影响扩展边际的效应确实存在。经济规模、贸易成本、人民币升值、区域经济一体化、外部冲击、语言的相通性、政治体制等变量对中国出口增长二元边际的影响机制不完全相同,表明要提高出口增长中的扩展边际比重,出口企业应实施市场多元化战略,将目标市场从传统高收入国家转移到发展中国家来,实现出口的稳定增长。     

数量驱动或创新驱动：异质型人力资本对经济增长的机制演进

基于1987-2017年中国省际面板数据,运用SYS-GMM模型研究异质型人力资本对经济增长的影响。在区分高级与基本人力资本基础上,基于招生率和收入维度,从全局和阶段差异视角剖析异质型人力资本对经济提速的机制演进。研究发现：全局而言,两种测度下基础和高级人力资本各自以数量及创新方式驱动经济增长,并呈现以数量驱动为主,数量、创新双驱动的增长模式;从演进视角看,两种测度均表明,高级人力资本创新驱动是新常态阶段经济增长的核心动力,但相比旧常态阶段,基础人力资本数量驱动日趋弱化并呈异质性;进一步研究表明,产业结构、城镇化及开放程度均对创新驱动有不同程度激励效应,而城镇化是挤出数量驱动的主要推手。