Average Monotonic Cooperative Games

A subclass of monotonic transferable utility (T.U.) games is studied: average monotonic games. These games are totally balanced. We prove that the core coincides with both the bargaining set à la Davis and Maschler and the bargaining set à la Mas-Colell. To obtain this result a technique based on reduced games is used. Journal of Economic Literature Classification Number: C71     

Regulation of Mobile Telephony across the European Union: An Empirical Analysis

In this paper I analyze the impact of regulatory policy on prices and demand for mobile telecommunications services across the European Union. I estimate a reduced form model of the mobile industry using panel data for the EU countries from 1998 to 2002. Among others, I find the following effects: liberalization of fixed telephone lines has a negative impact on prices and a positive impact on the demand for mobile services, and the introduction of mobile number portability has a negative impact on prices.*I am grateful to Toker Doganoglu, Gerd Hansen, Eric Kodjo Ralph, Guido Friebel, participants at the 30th EARIE Conference 2003, the 2nd International Industrial Organization Conference 2004 and the 19th Annual Congress of the EEA 2004, and anonymous referees for valuable comments. I would like to acknowledge the generous financial support from the Volkswagen Stiftung and the Munich Graduate School of Economics which made this research possible. All errors are mine.1 Source: European Commission (1994).     

污水处理厂污泥重金属含量及其浸出毒性分析——以上海某污水处理厂为例

为了评价污水处理厂污泥及其浸出液的潜在生态环境风险,以上海嘉定区某污水处理厂为例,采用硫酸/硝酸法和醋酸缓冲溶液法对污泥进行重金属总量和浸出毒性检测分析。同时,也研究了浸出液pH值、浸出时间及消解条件对浸出的影响。试验结果表明：1）污泥中Cu,Zn,Ni和Cr的含量分别是城市污泥中相应物质的平均含量的20,7.5,15和13倍,而Pb和Cd的含量与城市污泥的平均含量差不多;2）污泥中Cu与Cr主要以稳定形态存在,不同浸提方法下的浸出量相当,对于Zn和Ni,醋酸缓冲溶液的浸出量分别约为硫酸/硝酸溶液的22倍和18倍;3）浸出时间为20 h时浸出达到平衡,浸出液pH值对污泥重金属浸出能力的影响,因重金属元素种类的不同而存在较大差异,电热板消解和微波消解对浸出几乎没有影响;4）醋酸缓冲溶液制备的浸出液中,Ni的浸出质量浓度为16.3 mg/L,高于鉴别标准限值5 mg/L,而硫酸/硝酸浸提方法中重金属浸出浓度均未超过规定值。因此,该污水处理厂的污泥不适合卫生填埋,应积极寻求新技术对污泥进行合理处置并减少其潜在生态环境风险。     

大学英语分层次个性化教学模式探索

21世纪初教育部正式启动大学英语教学改革,学者和教师针对课程设置展开了积极的探索和讨论。高校应该充分考虑学生的差异,对学生进行不同层次教学,进行个性化培养。要保证学生在大学英语学习中具有选择权和主动权。EGP、ESP和EGE的教学并不矛盾,可以融为一体创建大学英语分层次个性化教学模式,满足学生和社会对于各种人才的多样化要求。     

Pitfalls in counterfactual analyses of policy rules

This analysis examines the validity of utilizing a subset of reduced form equations, such as from a VAR model, for the construction of counterfactual policy analyses. It is shown that the omission of one of the estimated reduced form (VAR) equations and the substitution of a counterfactual policy rule to complete the model severely limits the admissible structure of the economic model that could have generated the historical data.     

RECOVERING PORTFOLIO DEFAULT INTENSITIES IMPLIED BY CDO QUOTES

We propose a stable nonparametric algorithm for the calibration of “top‐down” pricing models for portfolio credit derivatives: given a set of observations of market spreads for collateralized debt obligation (CDO) tranches, we construct a risk‐neutral default intensity process for the portfolio underlying the CDO which matches these observations, by looking for the risk‐neutral loss process “closest” to a prior loss process, verifying the calibration constraints. We formalize the problem in terms of minimization of relative entropy with respect to the prior under calibration constraints and use convex duality methods to solve the problem: the dual problem is shown to be an intensity control problem, characterized in terms of a Hamilton–Jacobi system of differential equations, for which we present an analytical solution. Given a set of observed CDO tranche spreads, our method allows to construct a default intensity process which leads to tranche spreads consistent with the observations. We illustrate our method on ITRAXX index data: our results reveal strong evidence for the dependence of loss transitions rates on the previous number of defaults, and offer quantitative evidence for contagion effects in the (risk‐neutral) loss process.     

全固态PDM发射机的运行，维护与故障处理

近几年来,全固态中波发射机逐步取代了真空电子管发射机成为主流,大大地节省了发射台的日常运行费用和能源消耗,提高了安全播出质量,降低了停播率,减轻了机房工作人员的劳动强度。本文就是针对全固态中波广播发射机的使用与维护及日常运行环境进行粗浅的介绍。