A hybrid information approach to predict corporate credit risk

This study proposes a hybrid information approach to predict corporate credit risk. In contrast to the previous literature that debates which credit risk model is the best, we pool information from a diverse set of structural and reduced‐form models to produce a model combination based on credit risk prediction. Compared with each single model, the pooled strategies yield consistently lower average risk prediction errors over time. We also find that while the reduced‐form models contribute more in the pooled strategies for speculative‐grade names and longer maturities, the structural models have higher weights for shorter maturities and investment grade names.     

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).     

Behavioral assumptions and theory development: the case of transaction cost economics

From a critical realist perspective, I discuss the role played by behavioral assumptions in organization theories, and use transaction cost economics as an illustrative example. Core behavioral assumptions often constitute the foundation of the mechanismic explanations of a theory, and thus should play a pivotal role in theory development. I distinguish between assumption‐based and assumption‐omitted theory testing, and show that empirical research in transaction cost economics has been dominated by assumption‐omitted testing. To establish a solid foundation for a new theory, management researchers should pay more attention to assumption‐based testing. Copyright © 2006 John Wiley & Sons, Ltd.     

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。     

A Tutorial on Palm Distributions for Spatial Point Processes

This tutorial provides an introduction to Palm distributions for spatial point processes. Initially, in the context of finite point processes, we give an explicit definition of Palm distributions in terms of their density functions. Then we review Palm distributions in the general case. Finally, we discuss some examples of Palm distributions for specific models and some applications.     

Signaling quality with increased incentives

Previous work on informed-principal problems with moral hazard suggested that the principal should signal project quality by retaining a larger share of the project and hence lowering incentives for the agent. We show that this view is incomplete. If project quality and effort are complements and effort is more valuable for high-quality projects, a principal with a high-quality project may separate from a principal with a low-quality project by increasing incentives for the agent. This holds with a risk-neutral agent who is protected by limited liability as well as with a risk-averse agent and unlimited liability. A dynamic version of our model in which the agent learns project quality in later periods provides an explanation for the use of initially reduced royalty rates in business-format franchising contracts.     

A Reduced‐Form Model for Warrant Valuation

This paper studies warrant valuation using a reduced‐form model. Analogous to the credit risk literature, structural models require complete information about the asset value process and the firm’s liabilities. In contrast, reduced‐form models require only information about the firm’s stock price process. We introduce a reduced‐form model where the warrant holder is a price taker, and we relate our model to structural models appearing in the literature.     

离子交换法从烟道灰中提取铼的工艺研究

本工艺提出了一种从钼冶炼烟道灰中湿法回收铼的方法,过程中采用在稀硫酸体系中氧化浸出铼,水解及硫化法二段除钼,离子交换法富集铼,高氯酸淋洗,重结晶法精制,铼酸钾氢还原,铼的总回收率可达90%以上,有价金属得到了充分利用。     

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.