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This paper establish a first passage time model based on the Merton's structural model by using the method of geometric Brownian motion. In this paper, we consider the accounting noise and historical default record and then introduce a new incomplete information hypothesis. Besides, we introduce the stock's liquidity value into the model, and apply its method measurement which based on Merton's structural model to the first passage time model to obtain the endogenous default boundary. Based on the incomplete information, the conditional default probability is derived by using the default boundary. And at the last of this passage, we analysis the effect of the correlation between stock's price and company assets on the default probability.     

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Based on the default risk effect of reinsurance company for reinsurer, this paper studies the optimal reinsurance strategy by VaR optimality criterion. In a reinsurance contract, reinsurance company will charge the number of premium to undertake part of the insurer's loss. However, if the reinsurance company's commitment exceeds its solvency, the default risk will occur. In order to avoid the default risk and minimize the total risk of the insurance company, the paper introduces Wang's premium principle to obtain the optimal reinsurance policy under VaR risk measure. Some numerical examples are given to illustrate these results.     

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In this paper, the insurer is allowed to buy reinsurance and allocate his money among three financial securities: a defaultable corporate zero-coupon bond, a default-free bank account, and a stock, while the instantaneous rate of the stock is described by an Ornstein-Uhlenbeck process. The objective is to maximize the exponential utility of the terminal wealth. We decompose the original optimization problem into two subproblems: a pre-default case and a post-default case. Using dynamic programming principle, and then solving the corresponding HJB equations, we derive the closed-form solutions for the optimal reinsurance and investment strategies and the corresponding value functions     

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Concerning the problem that network congestion risk of computer network service system for some data frames having a full priority of transmission, a method about nonpreemptive limited-priority M/M/n/m queuing system model was proposed. Firstly, as the parameter r of limited-priority was introduced into the model, the data frame with full priority was converted to the one with limited priority. Secondly, in order to lower the risk of computer network service system and stabilize the network system further, the fairness among different priorities was studied in the model. Moreover, by making use of Total Probability Theorem, three results of the models, the average waiting time, the average dwelling time and the average queue length were obtained.     

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Credit valuation adjustment is the price adjustment of financial contract considering possible default of counterparty and it is an important way to measure counterparty risk. It is the key to establish a reasonable default dependence structure model. We introduce an economic state variable and shot noise processes in a Markov copula model and establish a regime switching Markov copula model with shot noise, where we can not only describe the impact of common economic conditions characteristics but also describe the credit name's characteristic. In this proposed model, we study martingale property of the model and the collateralized CVA of credit default swaps, and furthermore, we perfer some numerical calculations on the collateralized CVA and examine the impact of some model parameters on the CVA.     

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本文给出了上期望空间中独立随机变量部分和的最大不等式、指数 不等式、Marcinkiewicz-Zygmund不等式. 并且应用指数不等式和Marcinkiewicz-Zygmund不等式 研究了随机变量部分和序列完备收敛的性质.     

（Inco） Projective Modules of Relatively Hereditary Torsion Theroy

In the paper, we define(inco) project modules of relatively hereditary torsion theory Υ by intersection complement of module and study their properties; secondly, we define the(inco) Υ-semisimple ring by(inco) Υ-projective module and study their properties. When Υ is a trivial torsion theory on R-rood, we prove that R is a semisimple ring if and only if R is a(inco) semisimple ring and satisfies(inco) condition.     

Baжeвcкий不等式的改进及应用

本文推广了Ｂａжｅвｃкий关于变系数线性微分方程组解的估计式，从而得到时变线性系统谱的更精确的估计，把这结果应用于一类非线性时变系统的稳定性的讨论     

W-空间上满足积分型收缩条件的映射族的公共不动点结果

引进了两个实函数类φ和ψ,考虑了在W-空间上满足两种不同积分型收缩条件的映射族,然后证明了映射族满足反交换性或具有交换点时拥有唯一公共不动点.同时,给出了若干特殊结果.所得结果推广和改进了很多Banach收缩原理的推广结果.     

Ad Hoc网络马氏模型路由维护的性能分析

Ad Hoc网络可以用许多数学模型来描述.本文以DSR协议为基础,把每条链边的长度看作是一个生灭过程,建立了马氏模型.在此模型中,我们考虑了空间可重用和请求分组带有跳限的情形.基于马氏模型,本文引入了链边Υ-时有效的概念,推导了链边有效的概率,得出了路由有效的条件概率和路由的平均恢复次数.     

在约化模型下具有随机回收率的公司债券定价

在假设违约过程和利率过程相关的情形下,利用无套利原理构造了具有随机回收率的公司债券定价模型,然后运用偏微分方程方法给出了公司债券的价格表达式,最后讨论了模型中的参数对信用利差的影响.     

带有违约风险的可转换债券的简约型定价

本文考虑简约模型下带有违约风险的可转换债券的定价问题.假定市场中可转换债券的违约强度满足Vasicek模型,利用鞅方法获得了该模型下可转换债券的定价公式.此外,我们通过数值分析显示了模型参数变化对可转换债券价值影响的敏感性程度,结果也表明违约风险将降低可转换债券的价值.     

彩虹障碍期权的定价问题

采用偏微分方程方法研究了彩虹障碍期权的定价问题,推导出它满足的偏微分方程,通过求解这个偏微分方程得出了八种彩虹障碍期权的定价公式及四个看涨——看跌平价公式.     

具有一般跳幅度分布的跳扩散模型下永久公司债券的定价

在公司资产价值演化服从具有一般跳幅度分布的跳扩散模型下,采用结构化方法研究具有无限到期日公司债券的定价问题,通过微分方程的方法和无套利原理获得了公司债券,股东权益和公司总价值的定价表达式以及最佳违约边界的表达式.     

基于双指数跳扩散过程的公司债券定价

研究基于公司资产价值服从双指敷跳扩散过程,公司负债服从连续扩散过程的公司债券定价问题.首先用计价单位方法给出简单情况下以零息票债券为基础的公司债券定价问题的解析解;其次给出一般情况下公司债券定价问题的违约概率,并讨论信用价差的期限结构.实证分析表明该模型能较好地拟合实际情况.     

具有动态信用风险的可转债的定价研究

本文基于鞅方法的定价理论,在全面考虑赎回条款、回售条款、公司不具稳定性的信用风险以及转股时股市受到稀释作用对可转债价值的影响后,给出可转换债券一个比较精确的定价公式。应用这些公式对南京水运公司可转换债券做实证分析,结果表明:定价公式的数值与实际市场可转债的价格波动情况吻合相当好,能反映出良好的预测效果.因此该可转债定价结果将有助于发行公司、投资者、监管机构和中介机构更准确的了解可转债的定价机制,而发行公司、投资者、监管机构和中介机构对可转债定价机制的熟悉将有助于在我国证券市场建立起一种成熟稳健的避险工具,从而推动证券市场的发展。     

动态资产份额定价理论模型

运用倒向随机微分方程数学方法 ,建立了动态资产份额定价理论模型 .这一模型是资产份额定价法的改进 .求解模型得到动态资产份额定价理论公式 ,并得出结论 :资产份额定价公式完全可以作为特例 ,以离散时间意义和在不考虑动态投资的情况下 ,由动态资产份额定价理论公式得到 .     

基于信用利差与Logistic回归的公司违约概率测算模型与实证研究

用Logistic模型计算公司违约概率在实际应用中存在两个问题:一是在缺乏公司违约记录数据库或违约记录数据库不典型的情况下,无法应用该模型或模型计算结果不准确;二是现有Logistic违约概率模型忽视了不同行业财务指标分布特征的差异性,导致公司违约概率计算结果的准确性降低。针对问题一,本文通过公司债券信用利差计算市场隐含的公司违约概率,在Logistic变换的基础上进一步确定Logistic线性回归的参数,使得公司违约概率的计算结果符合债券市场的实际状况。针对问题二,通过不同行业关键财务指标的单因子方差分析,证实了行业间财务指标的分布特征具有显著性差异,通过拟合优度证实了区分行业建立Logistic违约概率模型可显著提高违约概率测算的准确性。本文Logistic违约概率模型的构建过程如下:通过初选财务指标的相关性分析,删除反映信息重复的财务指标;通过Logistic回归中财务指标系数的显著性检验,删除对违约概率解释能力弱的财务指标;以Logistic回归的拟合优度为标准,选取各样本行业Logistic违约概率模型的关键财务指标,建立了机械设备等5个样本行业的Logistic违约概率模型,为样本内行业公司违约概率的准确测算提供模型与方法。本文的创新与特色:一是在无套利条件下,通过公司债券信用利差计算市场隐含的公司违约概率,并对其进行Logistic变换,作为Logistic线性回归的被解释变量,解决了在缺乏公司违约记录数据情况下Logistic违约概率模型的参数估计问题;二是通过单因子方差分析方法,证实了行业间财务指标的分布特征具有显著性差异,说明应区分行业建立Logistic违约概率模型;三是通过财务指标间的相关分析删除反映信息重复的财务指标,通过财务指标系数的显著性检验删除对公司违约概率解释能力弱的财务指标,保证了Logistic违约概率模型中关键财务指标选取的合理性;四是实证研究结果表明,不同行业的Logistic违约概率模型的关键财务指标不同,同一财务指标的参数也存在显著差异。实证研究结果还表明,区分行业建立Logistic违约概率模型与不区分行业相比,前者可将拟合优度及调整后的拟合优度提高近1倍。本文研究结果对于提高公司违约概率测算的准确性具有重要参考意义,对于商业银行贷款定价、公司债券发行定价、银行信用风险管理具有重要参考意义。     

基于在线捆绑的易逝品动态定价模型研究

运用动态规划和组合优化理论,建立了基于在线捆绑的易逝品动态标价模型.针对是否补充缺货分别建立了紧急补货模型和失销模型.将有限的销售期限分割成N个时间决策单元,提出了每个决策单元的捆绑结构和捆绑包价格的确定方法.证明了紧急补货模型价值函数的可分解性、最优捆绑价格在时间上的非递减性和在存量上的非递增性;证明了失销模型最优期望收益在存量上的非递减性.该模型有助于实践中运用在线捆绑策略的易逝品生产和服务企业对捆绑包结构和捆绑包价格做出正确的决策.     

基于t-Copula的一篮子信用违约互换定价模型

为了刻画分布函数的厚尾特征和违约的传染性,构建了单因子t-Copula模型,以此研究一篮子信用违约互换(BDS)的定价问题。依据风险中性定价原理和顺序统计量方法,分别得到了第k次违约和n个参照实体中m个受保护的BDS价格的解析式.为了说明定价模型的有效性,用随机模拟方法分析了相应的数值算例.