Optimal taxation and redistribution in an OLG model with unemployment

This paper concerns redistribution via nonlinear income taxation in an overlapping generations model with two ability-types. We assume that the wage rates are determined by bargaining between unions and firms, meaning that the equilibrium is characterized by involuntary unemployment. We show that the policy instruments that are used to calculate the marginal labor income tax rate for each ability-type give rise to intertemporal tax base effects. In addition, since the relationship between the employment and the capital stock implies intertemporal production inefficiency at the second best optimum, imperfect competition in the labor market may itself justify capital income taxation.      

孵化网络结构、风险传播对孵化网络最终健康水平的影响——结构可视化的调节作用

风险在孵化网络中的传播影响孵化网络健康水平,并会导致在孵企业高失败率与低成长率。为实现有效的网络治理,以两家国家级孵化器形成的实际网络为例,运用复杂网络理论中的SIR模型和仿真方法,模拟特定情境下风险在不同网络结构中的传播机理及其对孵化网络最终健康水平的影响。研究发现：孵化网络结构、风险传播与网络健康间具有显著相关性;在低初始健康分布情景下,无标度网络具有更快的恢复速度;在不同网络结构下,可视化水平均有助于提升孵化网络风险化解能力。     

中国新疆与中亚五国对外经济发展水平比较

本文利用国际国内最新数据,从整体经济发展水平比较出发,通过进出口、外国直接投资、国际旅游等三方面指标,比较中国新疆与中亚五国的对外经济发展水平,并通过经济外向度综合指数做出进一步比较分析。总体而言,新疆经济对外开放水平与中亚五国相比有较大差距,需要在政策措施上加大力度,提高对外开放水平,特别是加快向西开放的步伐。     

基于VaR模型的最优套期保值比例探析——以美元远期套保为例

VaR模型被认为是兼顾投机套利与套期保值两大动机的衍生工具决策模型。国内文献对此讨论较少。基于其理论推导,可以归纳地认为VaR模型具有兼容性、一般性、"期权"特征和可操作性。以美元远期套保为例,研究发现,基于VaR模型的最优套保比较之传统最优套保比、最小方差最优套保比更有优势,能够解释中国企业运用衍生工具失败的原因。但据此推论,基于VaR模型确定最优套保比在实践中仍然存在一些问题,如非正态分布、现货头寸不确定、损益报告困难等。     

Measuring the unmeasurable: an application of uncertainty quantification to Treasury bond portfolios

We extract from the yield curve a new measure of fundamental economic uncertainty, based on McDiarmid’s diameter and related methods for optimal uncertainty quantification (OUQ). OUQ seeks analytical bounds on a system’s behaviour, even where aspects of the underlying data-generating process and system response function are not completely known. We use OUQ to stress test a simple fixed-income portfolio, certifying its safety—i.e. that potential losses will be ‘small’ in an appropriate sense. The results give explicit tradeoffs between: scenario count, maximum loss, test horizon, and confidence level. Unfortunately, uncertainty peaks in late 2008, weakening certification assurances just when they are needed most.     

人民币汇率变动的物价传递效应:多结构变化协整回归分析

现有研究物价传递效应的文献以线性模型为主,甚少关注物价传递过程中可能存在的结构变化,本文在充分考虑我国转轨时期所面临的各种经济冲击的条件下,利用最新发展的多结构变化协整回归方法考察了1994年1月至2008年12月间人民币汇率变动的物价传递效应。研究结果表明,人民币汇率变动的物价传递效应分别在1998年8月、2002年10月、2005年8月及2007年7月发生了四次结构变化,传递效应虽总体趋减,但2007年7月后出现了反复,且符号也发生了改变。在上述结论基础上,本文提出了相关政策建议。     

长三角地区居民消费结构及水平的统计分析

应用因子分析和聚类分析的方法,对2006年长三角16座城市居民的消费结构、消费水平进行分析和比较。结果表明,长三角16城市在居民可持续消费能力上存在差距,在居民消费结构和消费水平上可分为五类,其中上海、杭州的消费水平最高。文章还对如何提高居民消费水平,促进经济协调发展提出了对策。     

磷化氢环流熏蒸杀虫最低密闭时间的研究

磷化氢环流是一个复杂的过程,既要掌握有效的浓度,又要维持足够的密闭时间.在一定磷化氢浓度下,一次性全部杀死粮内害虫的最佳密闭时间应等于施药后磷化氢浓度上升到杀虫有效浓度的时间 杀死该粮堆内害虫成虫和幼虫的时间 杀死成虫死亡前产出的卵在此环境中的孵化时间或存在的蛹的发育时间 杀死卵孵化出的幼虫和成虫的时间.实验证实,在粮温10-24℃、磷化铝3g/m3剂量下,采取环流熏蒸措施,杀死玉米象和赤拟谷盗最低需要21d,杀死谷蠢需要26～28d.     

American step-up and step-down default swaps under Lévy models

This paper studies the valuation of a class of default swaps with the embedded option to switch to a different premium and notional principal anytime prior to a credit event. These are early exercisable contracts that give the protection buyer or seller the right to step-up, step-down, or cancel the swap position. The pricing problem is formulated under a structural credit risk model based on Lévy processes. This leads to the analytic and numerical studies of several optimal stopping problems subject to early termination due to default. In a general spectrally negative Lévy model, we rigorously derive the optimal exercise strategy. This allows for instant computation of the credit spread under various specifications. Numerical examples are provided to examine the impacts of default risk and contractual features on the credit spread and exercise strategy.