Model selection in random effects models for directed graphs using approximated Bayes factors

With the development of an MCMC algorithm, Bayesian model selection for the p ₂ model for directed graphs has become possible. This paper presents an empirical exploration in using approximate Bayes factors for model selection. For a social network of Dutch secondary school pupils from different ethnic backgrounds it is investigated whether pupils report that they receive more emotional support from within their own ethnic group. Approximated Bayes factors seem to work, but considerable margins of error have to be reckoned with.     

注册会计师行业监管的若干问题研究

针对我国对舞弊的会计师事务所处罚力度明显不够的事实，监管机构应加大处罚力度，在确定合理处罚的基础上选择适当的监管力度，政府监管力度按成本效益原则确定监管费用的最优投入，决定监管机构的规模和大小，并完善相关的机构建设。     

Vertical Restraints and Market Access

This paper analyzes vertical restraints in relation to market access issues. In Section II we briefly review the recent three major trade conflicts between Japan and the USA in light of vertical restraints. In Section III we review the major policy lessons of the economics literature of vertical restraints, and analyze whether we need a special treatment for vertical restraints abroad for a market access reason. In Section IV we evaluate the policy options towards foreign foreclosure and suggest that nondiscriminatory application of foreign or home competition policy should be the mechanism to address such concern instead of trade policy actions such as voluntary import expansions.     

Valuation of commodity derivatives in a new multi-factor model

This paper extends existing commodity valuation models to allow for stochastic volatility and simultaneous jumps in the spot price and spot volatility. Closed-form valuation formulas for forwards, futures, futures options, geometric Asian options and commodity-linked bonds are obtained using the Heston (1993) and Bakshi and Madan (2000) methodology. Stochastic volatility and jumps do not affect the futures price at a given point in time. However, numerical examples indicate that they play important roles in pricing options on futures. This revised version was published online in June 2006 with corrections to the Cover Date.     

不完全信息与网络产业激励性规制改革

规制体制改革的核心是解决信息不对称下的最优激励问题，规制体制设计的关键就是要设计有效的激励合约，为企业提供适当的激励以达到成本效率，从激励角度看，价格上限规制的效率最高，竞争是重要的激励性体制，网络产业竞争体制形成的关键是约束在位运营商排斥竞争行为和建立有效的互联资费政策。     

纵向一体化网络的接入定价研究

中国铁路、煤气、自来水、邮政等绝大多数网络型产业的结构改革将选择纵向一体化与自由接入作为突破口，研究纵向一体化网络的接入定价理论和政策已成为中国网络型产业规制政策研究的一个重要问题。本文首先依据资源最优配置、次优配置、生产效率等原则，研究了不同的接入定价理论，详细探讨了不同的接入定价方法，最后进一步分析了纵向一体化网络在不同政策目标下的接入定价政策选择。     

股票价格均值回归理论研究综述

随机漫步理论认为股票的价格是不能预测的,许多实证检验的结果也支持了这一结论。但是,近年来均值回归理论对随机漫步理论提出了挑战。从长期来看,股票价格呈均值回归是必然的;均值回归具有不对称性;政府行为对股票的均值回归具有一定的影响。     

对金融衍生品市场内幕交易的一些新思考--澳大利亚现行的反内幕交易法及其带给我们的若干启示

本文着眼于澳大利亚在治理金融衍生品市场内幕交易中积累的丰富经验,针对一个崭新的前瞻性课题,即金融衍生品市场的内幕交易问题展开研究。作者认为,由于内幕交易与信息非对称性之间存在的内在冲突,实际上反内幕交易法规很难有效地阻止金融衍生品的内幕交易行为,过于复杂的反内幕交易法规会对市场产生一些负面影响,而放松内幕交易监管这一新思维将对市场的良性发展更为有益,应该让市场来决定内幕交易行为的“存亡”。但目前最为现实、温和的选择仍然是修改现行反内幕交易法,以维护市场的公平性和有效性。最后,笔者对如何缓解中国目前内幕交易猖獗的现状提出建议。     

Telecommunications policy and individuals with disabilities: Issues of accessibility and social inclusion in the policy and research agenda

Information and communications technologies have become an integral part of life in an information society, affecting employment, education and many other daily activities. For individuals with disabilities, equal access to telecommunications remains a concern, as many technologies that are developed do not allow for equal access. Law and policy have made significant progress in some nations, but sizeable barriers remain to the social inclusion of individuals with disabilities in telecommunications technologies and services. This paper examines the importance of equal access to telecommunications for individuals with disabilities in both the formulation and the implementation of policy. Analyzing issues of policy and implementation, this paper discusses policy questions and potential areas of research to better understand the relationship of telecommunications policy to access for persons with disabilities.     

A saddlepoint approximation to the distribution of the sum of independent non‐identically uniform random variables

Calculating the probability of the corresponding significance point is important for finite sample sizes. However, it is difficult to evaluate this probability when the sample sizes are moderate to large. Under these circumstances, consideration of a more accurate approximation for the distribution function is extremely important. Herein, we performed a saddlepoint approximation in the upper tails for the distribution of the sum of independent non‐identically uniform random variables under finite sample sizes. Saddlepoint approximation results were compared with those for a normal approximation. Additionally, the order of errors of the saddlepoint approximation was derived. © 2014 The Authors. Statistica Neerlandica © 2014 VVS.