变动均值和方差资产配置模型的应用研究

本文在均值-方差模型的基础上,以改善估计误差为主线,选取了10种变动均值-方差的资产配置模型,以等权重策略为基准,运用了确定性等价收益和Alpha值为判断准则,同时考虑了允许卖空限制和非允许卖空的情况,实证研究结果表明：虽然在资本市场中配置模型并不能显著战胜等权重策略,但随着投资范围的扩大,模型开始显现配置效果,尤其在Alpha准则下,变动均值-方差资产配置显著。同时本文还将实证结果和目前我国投资者的实际资产配置情况进行了比较,发现了现实配置结构中的不合理之处,并提出了相应的改善建议。最后对4类常用资产进行了模拟研究,其结果也进一步证实了本文的结论。     

信用风险中回收率分布的双Beta模型

本文研究了随机回收率的分布,建立了回收率的双Beta分布密度模型,它具有双峰分布的特点,这与Moody公司的最新研究相吻合,弥补了现有回收率分布模型均为单峰的不足。利用基于数论网格的序贯优化算法对所建模型的参数做出了估计,借助于核密度估计的工具,进行了实证分析,结果表明双Beta模型的拟合误差很小,远小于Beta模型的误差,它是表示回收率理想的模型。最后给出了抽取双Beta分布随机数的方法。     

消费者低碳消费行为的心理归因和政策干预路径:一个基于扎根理论的探索性研究

引导消费者的生活方式和消费模式转向低能耗、低污染、低排放的方向是当前一个重大课题。然而,消费者为什么会实行低碳消费行为模式(即低碳消费行为归自何种心理)?如何促进和引导消费者的低碳消费行为(即低碳消费行为如何才能持续)?对于这两个关键性问题目前还缺乏深度的研究。本文通过深度访谈,应用扎根理论这一探索性技术探究低碳消费行为的深层次心理归因(解决第一个问题)及相应的政策干预路径(解决第二个问题)。研究发现,个体心理意识、社会参照规范两个主范畴是低碳消费行为的内部和社会心理归因。但它们对于低碳消费行为的促成机理并不一致:个体提高心理意识产生相应的低碳消费行为,这归于认知性学习范畴;个体观察参照群体的消费模式及其结果产生特定的低碳消费行为,这归于观察性学习范畴。不同心理控制源的个体(内控型还是外控型)之间也存在一定的差异。低碳传播沟通和情境结构变革两个主范畴是低碳消费行为的政策干预变量,且它们是相互补充、相互配合的。通过传播沟通影响个体心理意识、社会参照规范,通过情境结构变革影响低碳消费行为的成本收益结构成为主要的政策干预路径。这些研究结论可以为政府制定有效的干预政策,为引导消费者的消费行为模式提供理论基础和政策借鉴...     

中国股票市场的信息反应曲线和股票价格波动的非对称性

股票价格波动对于市场信息的反应过程具有非对称性。通过利用多种非对称性GARCH 模型,描述和检验了沪市股票日收益率序列的条件波动性,并通过对股票市场信息影响曲线的分析,发现沪市股票价格波动中存在显著的非对称性反应。这说明股市波动对于不同的政策干预和信息冲击具有不同程度的反应,“利好消息”对股市的刺激作用仍然需要其他市场干预的配合才能发挥出来。     

同种商品不同月份期货组合风险评价模型研究及应用

以期货合约的每一交易日的对数涨跌率来反映市场风险,借助VaR风险价值法,运用加权核估计技术(WKDE)和指数加权滑动模型(EWMA),建立了基于期货组合中持有头寸不同且可以进行风险对冲的期货组合市场风险非线性叠加评价模型,解决了同种商品、不同月份期货组合每一交易日最大损失的确定问题,并通过实证研究验证了模型的实用性.该模型的特点一是借助WKDE法预测组合中单个合约每一交易日涨跌率最大日亏损值,充分体现了期货合约涨跌率的实际走势,使VaR估计更加精确.二是通过动态迁移相关系数矩阵的计算保证了模型的精确性.采用EWMA模型预测动态变化的方差-协方差矩阵,从实证的角度得到更精准的动态迁移相关系数矩阵.三是考虑了组合中多头和空头不同头寸之间的风险对冲,避免了实际中期货组合风险的线性相加而造成放大风险或减少风险的不准确性,从而能较好地保证了模型的预测精度及准确性.四是通过基于风险非线性叠加建立的期货组合风险评价模型解决了SPAN系统中期货组合风险的线性叠加问题,从而得到更合理的组合风险预测值.     

基于不同动机的联盟控制方式选择及其对联盟绩效的影响——中国企业联盟的实证分析

企业为了不同的目标建立战略联盟,而有效的联盟控制是实现目标的重要保证.本文从战略联盟的动机出发,提出实现不同联盟目标所应采取的控制方式,并研究了不同的联盟控制方式对联盟绩效的影响.通过企业间联盟的数据对本文相关假说进行了实证检验.     

Computing Optimal Beams in Two and Three Dimensions

The problem of computing an optimal beam among weighted regions (called the optimal beam problem) arises in several applied areas such as radiation therapy, stereotactic brain surgery, medical surgery, geological exploration, manufacturing, and environmental engineering. In this paper, we present computational geometry techniques that enable us to develop efficient algorithms for solving various optimal beam problems among weighted regions in two and three dimensional spaces. In particular, we consider two types of problems: the covering problems (seeking an optimal beam to contain a specified target region), and the piercing problems (seeking an optimal beam of a fixed shape to pierce the target region). We investigate several versions of these problems, with a variety of beam shapes and target region shapes in 2-D and 3-D. Our algorithms are based on interesting combinations of computational geometry techniques and optimization methods, and transform the optimal beam problems to solving a collection of instances of certain special non-linear optimization problems. Our approach makes use of interesting geometric observations, such as utilizing some new features of Minkowski sums.     

对组织学习、核心竞争能力、战略柔性与企业竞争绩效的理论剖析与实证研究 --探索中国企业增强动态竞争优势之路

在当前超强竞争时代,组织学习、核心竞争能力和战略柔性,越来越成为企业竞争的焦点问题,成为企业营造持久的动态竞争优势的战略武器.本文在对前人有关研究进行回顾、总结和归纳的基础上,开创性地把企业核心竞争能力划分为技术能力、市场营销能力和整合能力这三个关键构成要素,识别出组织学习的三个关键维度,深入剖析了战略柔性的内涵与本质,并在此基础上,论述了它们之间的互动关系及其对企业竞争绩效的影响.最后,本文以来自中国企业的实际调研数据为基础,运用基于偏最小二乘法的结构方程模型(SEM),对上述问题进行了实证分析,剖析了本项研究对中国企业管理的启示.     

Learning How and Learning What: Effects of Tacit and Codified Knowledge on Performance Improvement Following Technology Adoption

This paper examines effects of tacit and codified knowledge on performance improvement as organizations gain experience with a new technology. We draw from knowledge management and learning curve research to predict improvement rate heterogeneity across organizations. We first note that the same technology can present opportunities for improvement along more than one dimension, such as efficiency and breadth of use. We compare improvement for two dimensions: one in which the acquisition of codified knowledge leads to improvement and another in which improvement requires tacit knowledge. We hypothesize that improvement rates across organizations will be more heterogeneous for dimensions of performance that rely on tacit knowledge than for those that rely on codified knowledge (H1), and that group membership stability predicts improvement rates for dimensions relying on tacit knowledge (H2). We further hypothesize that when performance relies on codified knowledge, later adopters should improve more quickly than earlier adopters (H3). All three hypotheses are supported in a study of 15 hospitals learning to use a new surgical technology. Implications for theory and practice are discussed.     

The impact of learning opportunities and decision authority on occupational health

In an investigation of 418 employees in the Norwegian Postal Service, employees with high learning opportunities and high decision authority were found to be better off on psychological functioning, health and organizational outcome variables than employees with low scores on these variables. Decision authority and learning opportunities had specific and independent impact on subjective health, psychological functioning, coping style and organizational outcome variables. There were, however, also interaction effects between demands, learning opportunities, and decision authority on subjective health. Learning opportunities and decision authority were operationalized with a questionnaire, supplemented with questions on the opportunities to learn skills beyond the present job situation. It is suggested that this is a particularly important dimension for coping with the present day rapid changes in working life, where the objective for many workers will be to broaden their repertoire and competence to increase their flexibility in the labour market.