用期权定价模型估价创业企业的价值

本通过对创业企业期权特征的分析，以欧式带分红期权定理为基础，建立了创业企业价值评估的期权评估模型，最后就模型进行了实例分析。     

期权合约下基于CVaR的订单农业供应链协调研究

在农产品价格随机波动背景下，以包含一个风险规避型农户和一个风险中性公司的订单农业供应链为研究对象，运用条件风险价值(CVaR)准则研究订单农业供应链最优策略与协调问题。研究结果表明，分散决策情形下的农产品产量和决策双方总收益均低于集中决策情形。对此，在订单农业供应链中引入期权合约，研究发现当农户风险规避程度不很低时，期权合约能够促使农户与公司均实现帕累托改进，并且在期权合约下，农户可通过行权应对农产品价格波动风险，保证农产品产量和自身收益不受风险规避行为的影响；进一步研究表明，当农户风险规避程度较高时，期权合约能够实现订单农业供应链的完美协调。     

离散时间美式期权套期及停时分析

本文主要证明了在不存在交易成本的市场假设下离散时间美式期权套期价值过程{Vt，Ft，t≥0}为鞅。并且研究了美式期权的停时，分别给出了美式期权的可停时，首停时，最优停时的方程表达式，同时讨论了与他们相关的期望特征，以及研究了美式期权定价问题。     

连续支付红利的跳—扩散模型交换期权定价

在假设股票连续支付红利,且股票价格过程服从Poisson跳—扩散过程的条件下,建立了股票价格行为模型,应用保险精算法给出了欧式交换期权的定价公式,推广了Merton关于期权定价的结果.     

模糊环境下美式看跌期权的定价研究

应用模糊集理论将无风险利率和波动率进行模糊化,以梯形模糊数替代精确值,将美式期权的定价模型扩展到美式期权模糊定价模型.得到了模糊风险中性概率表达式,并在此概率测度下推导出多期二叉树模糊定价模型,以及二叉树上各节点以梯形模糊数表示的模糊期权价值,以数值模拟演示了美式看跌期权的模糊定价过程.最后分析了不同风险偏好投资者在不确定环境下的套利决策行为,结果表明风险偏好大的投资者具有较高的置信水平、较小的主观模糊期权价格以及较大的无风险套利区间.     

随机利率下的PPP项目实物期权评价研究

PPP项目通常实施周期长,风险突出。传统的实物期权评价方法考虑了未来的不确定性和管理者柔性的价值,但是一般假设无风险利率是固定的,不符合利率长期内波动的特点,会造成投资者决策失误。本文考虑了未来无风险利率波动条件下,PPP项目中实物期权的价值。首先分析了PPP项目中通常存在的期权形式,其次研究了无风险利率三角逆变函数以及在此基础上得出模拟实物期权模型,并用案例对比分析固定利率和随机利率下的期权价值。结果显示,随机利率比固定利率下的期权价值更高,研究结论可以为PPP项目的投资者进行决策提供重要依据。     

产业生命周期视角下的并购期权价值评估方法优化研究

由于并购活动具有期权的特点,其价值常采用Black-Scholes模型计算。但传统的Black-Scholes模型没有考虑产业生命周期对并购期权价值的影响。本文分析了产业生命周期不同阶段并购期权价值的特点,指出期权价值随产业生命周期的不同发展阶段而变化。研究通过采用Gompertz曲线预测模型拟合产业生命周期曲线,并对其作适当变换,推导出了修正系数η_t,对并购期权价值的Black-Scholes评估模型进行了优化。这种优化有助于避免评估过程中的高估风险,从而使并购价值的计算更合理,确保并购决策更具科学性。     

随机支付红利的跳-扩散模型的期权定价

假设股票随机支付红利,且红利的大小与支付红利时刻及股票价格有关,并假设股票价格过程服从跳—扩散模型(其中跳跃过程为Poisson过程)的条件下,建立了股票价格行为模型,应用保险精算法给出了欧式看涨和看跌期权的定价公式,推广了Merton关于期权定价的结果。     

突发事件冲击下基于或有支付机制的创投融资决策

探讨了突发事件冲击下基于或有支付机制的创业融资优化决策问题.假定创业企业利润流服从跳跃-扩散过程,运用实物期权方法推导出投资机会价值与最优投资时机,给出了最优的或有支付决策,使得创业企业家和风险投资家愿意共同支持给定的创业企业的增长策略.研究发现,突发事件时创业企业家和风险投资家的最优投资时机不受或有支付类型的影响.突发事件的平均发生率越大,双方共同投资的时机越早.利润流跳跃幅度越大,共同投资的时机也越早.目标实现时刻进行支付的或有支付具有更高的投资机会价值,可变数额或有支付具有更高的投资机会价值.     

决策依赖不确定条件下基于复合实物期权估值的工程系统投资决策研究

不确定性是复杂工程系统的内在属性,在决策依赖不确定条件下对工程系统的投资决策需考虑不确定性与决策过程之间的交互作用,使得投资决策问题的求解非常困难.提出了决策依赖不确定条件下复合实物期权估值的最小二乘模拟算法,方法较好地解决了在决策依赖不确定条件下由于不同期权价值相互耦合所带来的计算复杂性,进一步拓展了最小二乘模拟算法在期权估值中的应用,基于该方法,可以比较方便地解决决策依赖不确定条件下工程系统投资决策问题.     

On the distributions of the ratios of the extreme roots to the trace of the Wishart matrix

In this paper, the authors cosider the derivation of the exact distributions of the ratios of the extreme roots to the trace of the Wishart matrix. Also, exact percentage points of these distributions are given and their applications are discussed.     

On the comparison between the APV and the NPV computed via the WACC

The valuation of levered investment in the practice is made with the WACC approach, even if the superior technique of the APV is available. The paper shows that the APV can be interpreted as the arbitrage free value of the portfolio made by an investment and a supporting loan. Therefore the WACC evaluation, generally different from the APV, allows for arbitrage. We provide various conditions which completely characterize the sign of the error as a functions of all the variables entering the model.     

用常微分方程模型分析预防和隔离措施对SARS发病率的影响

通过建立常微分方程模型 ,分析了预防和隔离措施对 SARS发病率的影响 ,并把计算结果与实际统计数据进行了比较 ,结果表明 ,及时高效的预防和隔离措施能够有效地控制 SARS的传播 .     

From the neutrino to the edge of the universe

Two recent findings necessitate a closer look at the existing standard models of particle physics and cosmology. These are the discovery of neutrino oscillation, and hence a non-zero mass on the one hand and, on the other, observations of distant supernovae which indicate that contrary to popular belief, the universe would continue to expand for ever, possibly accelerating in the process. In this paper it is pointed out that relatively recent studies which indicate a stochastic, quantum vacuum underpinning and a fractal structure for space time, reconcile both of the recent observations, harmoniously.     

On the Gap in the Spectrum of the Translations

The spectrum of the translations in local quantum field theory will be analyzed in order to show that in a positive energy representation without vacuum vector and with lowest mass m₁ there is no gap in the spectrum which is larger than 2m₁. In particular in a zero mass representation there is no hole at all. These results are obtained with methods of analytic functions of several complex variables.     

From the subalgebras of the square to the discriminator

Presented by A. F. Pixley.     

On the Decomposition of the Riesz Operator and the Expansion of the Riesz Semigroup

For a Riesz operator T on a reflexive Banach space X with nonzero eigenvalues denote by E(λ_i; T) the eigen-projection corresponding to an eigenvalue λ_i. In this paper we will show that if the operator sequence is uniformly bounded, then the Riesz operator T can be decomposed into the sum of two operators T_p and T_r: T = T_p + T_r, where T_p is the weak limit of T_n and T_r is quasi-nilpotent. The result is used to obtain an expansion of a Riesz semigroup T(t) for t ≥ τ. As an application, we consider the solution of transport equation on a bounded convex body.     

On the dependence of the growth rate on the length of the defining relator

Let { } be a sequence of finitely presented groups with generating setA={a1, …, am}, and letRk be the symmetrized set of words over the alphabetA∪A−1 obtained from the defining words and their inverses by all cyclic shifts. We shall assume that the words inRk are cyclically irreducible, and their lengths tend to ∞ ask increases. In the paper, it is proved that ifRk satisfies the small cancellation conditionC'(1/6) and the number of relators increases not very rapidly with increasingk, then the growth rate ψ(Gk) tends to 2m−1 ask→∞. Translated fromMatematicheskie Zametki, Vol. 65, No. 4, pp. 611–617, April, 1999.