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本文研究了三叉树模型下的等价鞅测度刻划问题,得到了三叉树模型的最小熵鞅测度,逆相对熵鞅测度,方差最优鞅测度和极小鞅测度的精确表达式。 相似文献
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设半参数回归模型Y(n)i=β·x(n)i+g(t(n)i)+E(n)i,i=1,2,…,n,本文由最小二乘法和一般加权方法定义的β、g(t)的估计量βn,gn(t),在误差为鞅差序列下获得了βn,gn(t)的r(≥2)阶平均相合性. 相似文献
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本文研究金融市场中一类特殊半鞅模型,其价格过程具有X=LD的形式,这里L是局部有界鞅,D是可料有限变差过程.对这类模型我们导出其等价鞅测度存在的充分必要条件.另外,我们将[2]中的条件/△M/≤C推广到M为局部有界鞅,得到相应的结果. 相似文献
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资产定价基本定理是金融数学中的基本结果.利用半鞅可料表示性与半鞅向量随机积分的Girsanov定理获得了半鞅市场完备的特征(定理2.1),它扩展了[3]中的结论. 相似文献
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本文主要研究了一类连续半鞅的极大不等式.利用伊藤公式和Lenglart控制定理,得到了它们的极大不等式,推广了文献[9]的主要结果. 相似文献
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本文引进了H-值半鞅测度,研究了其基本性质和与之相联系的随机积分,本文还引入了H-值半鞅测度序列依分布弱收敛的概念,建立了H-值半鞅测度的极限定理,给出了H-值半鞅测度弱收敛的条件。 相似文献
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万上海 《数学的实践与认识》2010,40(16)
基于预先给定的目标收益率,利用投资者对低于目标收益率的风险损失和高于目标收益率的风险报酬之间的权衡,给出了一些非对称风险度量模型,特别其中一种风险度量是低于参考点的方差和高于参考点的方差的加权和,它利用二阶上偏矩来修正二阶下偏矩,进一步建立了在该非对称风险度量下的组合投资优化模型,并证明了该模型在三阶随机占优的意义下是有效的.此外,还给出了其它3个模型与三阶随机占优准则是否一致的结论,并对所给出的几个组合证券投资模型的求解方法及其应用进行了分析.以上研究和分析为投资者在选择投资模型时避免盲目性、任意性提供了有益的决策参考. 相似文献
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The purpose of this article is to provide a straightforward model for asset returns which captures the fundamental asymmetry in upward versus downward returns. We model this feature by using scale gamma distributions for the conditional distributions of positive and negative returns. By allowing the parameters for positive returns to differ from parameters for negative returns we can test the hypothesis of symmetry. Some applications of this process to expected utility and semi-variance calculations are considered. Finally we estimate the model using daily UK FT100 index and Futures data. 相似文献
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Interpolation theorems on weighted Lorentz martingale spaces 总被引:2,自引:0,他引:2
Yong JIAO~ Li-ping FAN Pei-de LIU School of Mathematics Statistics Wuhan University Wuhan China 《中国科学A辑(英文版)》2007,50(9):1217-1226
In this paper several interpolation theorems on martingale Lorentz spaces are given.The proofs are based on the atomic decompositions of martingale Hardy spaces over weighted measure spaces.Applying the interpolation theorems,we obtain some inequalities on martingale transform operator. 相似文献
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《European Journal of Operational Research》1999,114(2):304-319
The popularity of downside risk among investors is growing and mean return–downside risk portfolio selection models seem to oppress the familiar mean–variance approach. The reason for the success of the former models is that they separate return fluctuations into downside risk and upside potential. This is especially relevant for asymmetrical return distributions, for which mean–variance models punish the upside potential in the same fashion as the downside risk.The paper focuses on the differences and similarities between using variance or a downside risk measure, both from a theoretical and an empirical point of view. We first discuss the theoretical properties of different downside risk measures and the corresponding mean–downside risk models. Against common beliefs, we show that from the large family of downside risk measures, only a few possess better theoretical properties within a return–risk framework than the variance. On the empirical side, we analyze the differences between some US asset allocation portfolios based on variances and downside risk measures. Among other things, we find that the downside risk approach tends to produce – on average – slightly higher bond allocations than the mean–variance approach. Furthermore, we take a closer look at estimation risk, viz. the effect of sampling error in expected returns and risk measures on portfolio composition. On the basis of simulation analyses, we find that there are marked differences in the degree of estimation accuracy, which calls for further research. 相似文献
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In this paper, we consider the optimal consumption and portfolio policies with the consumption habit constraints and the terminal wealth downside constraints, that is, here the consumption rate is greater than or equal to some nonnegative process, and the terminal wealth is no less than some positive constant. Using the martingale approach, we get the optimal consumption and portfolio policies. 相似文献
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The recent crisis made it evident that replicating the performance of a benchmark is not a sufficient goal to meet the expectations of usually risk-averse investors. The manager should also consider that the investors are seeking downside protection when the benchmark performs poorly and thus they should integrate a form of downside risk control. We propose a multiperiod double tracking error portfolio model which combines these two goals and provides enough flexibility. In particular, the control of the downside risk is carried out through the presence of a floor benchmark with respect to which we can accept different levels of shortfall. The choice of a proper measure for downside risk leads to different problem formulations and investment strategies which can reflect different attitudes towards risk. The proposed model is tested through a set of out-of-sample rolling simulations in different market conditions. 相似文献
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均值方差偏好和期望损失风险约束下的动态投资组合 总被引:1,自引:0,他引:1
本文在均值方差框架下,研究了期望损失风险约束下的连续时间动态投资组合问题。运用鞅理论和凸对偶方法,分别给出了最优财富和最优投资策略的解析式,而且两基金分离定理仍然成立。最后通过数值例子分析了风险约束对最优投资策略的影响。 相似文献
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Several interpolation theorems on martingale Hardy spaces over weighted measure spaces are given. Our proofs are based on the atomic decomposition of martingale Hardy spaces over weighted measure spaces. As applications of interpolation theorems, some inequalities of martingale transform operator are obtained. 相似文献