公司价值与财务信息的相关性:基于中国上市公司的研究

本文以778家上市公司1998—2002年5年间的3890个观测值为样本,研究了公司价值与财务信息的相关性。结果表明,ST、PT公司的价值测度与综合短期利润测度存在不显著的负相关关系;既发行A股又发行B股的上市公司的价值测度与综合短期利润测度在0.01水平下显著正相关性,利润测度提供了约2%的公司价值解释力;对于绝大多数的经营正常的A股公司,价值测度与综合短期利润测度在0.01水平下显著正相关性,利润测度提供了约18%的公司价值解释力。     

Fuzzy profit measures for a fuzzy economic order quantity model

Changing economic conditions make the selling price and demand quantity more and more uncertain in the market. The conventional inventory models determine the selling price and order quantity for a retailer’s maximal profit with exactly known parameters. This paper develops a solution method to derive the fuzzy profit of the inventory model when the demand quantity and unit cost are fuzzy numbers. Since the parameters contained in the inventory model are fuzzy, the profit value calculated from the model should be fuzzy as well. Based on the extension principle, the fuzzy inventory problem is transformed into a pair of two-level mathematical programs to derive the upper bound and lower bound of the fuzzy profit at possibility level α. According to the duality theorem of geometric programming, the pair of two-level mathematical programs is transformed into a pair of conventional geometric programs to solve. By enumerating different α values, the upper bound and lower bound of the fuzzy profit are collected to approximate the membership function. Since the profit of the inventory problem is expressed by the membership function rather than by a crisp value, more information is provided for making decisions.     

考虑运营期收益的项目建设期时间/费用交换问题(TCTP/R)研究

给出了考虑运营期收益的项目建设期时间/费用交换问题DTCTP/R的概念,讨论了项目工期/收益的函数关系,建立了优化的数学模型,并且将遗传算法应用于问题的求解.最后,结合一个案例说明了在对建设期优化时,应当考虑其对项目运营收入的影响,从全局的角度来进行时间/费用的优化,所得结果才准确与可靠.     

The influence of fluorine on the asymmetric reduction of fluoromethyl ketones

A comparative study of the asymmetric reduction of representative aryl and alkyl α-fluoro- and α-chloromethyl ketones using (−)-diisopinocampheylchloroborane [(−)-DIP-Chloride™] and (−)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane [R-Alpine-Borane^®] has been made. It was observed that DIP-Chloride™ is superior in terms of the rate and enantioselectivity for both classes of halo-ketones. While the reduction of monofluoroacetone and trifluoroacetone with DIP-Chloride™ provided the product alcohols in 61% ee and 96% ee, respectively, the reduction of difluoroacetone yielded only 5% ee. The influence of a lone halogen atom was not observed for monochloroacetone, all of which point towards a chelating effect of monofluoroacetone on the Lewis acidic chloroborane.     

Regiocontrolled fluorination of 2-hydroxyalkyl dihydropyrans and carbonyl derivatives

Reaction of polysubstituted 2-hydroxyalkyldihydropyrans with DAST led regiospecifically to fluorination at the exocyclic position, except for primary alcohols. Difluorination of carbonylated analogues with deoxo-fluor™ occurred also regioselectively. The unexpected stability and synthetic potential of these new allylic fluorides are discussed.     

寡头竞争中的价格空间歧视研究

本先建立空间连续的价格歧视模型，得出竞争厂商进行价格空间歧视将得到更大利润占有更多的消费剩余。接着讨论了空间连续的价格歧视模型的局限性，为了增强可操作性提出价格空间歧视离散化。得出在空间差异竞争市场中，市场细分将增加竞争厂商的利润，同时得出竞争厂商价格空间歧视最大化均衡利润的条件。     

电力市场中合同电量与竞争电量交易比例的研究

在单边开放的区域电力市场中,合理的合同电量与竞争电量交易比例是保证电力市场有效运行的一个重要环节。竞争电量所占的比例将主要取决于当前发电公司的市场行为。首先使用BP神经网络对电力需求弹性系数进行了预测,然后以长期电力市场均衡为目标函数,考虑贵州电网发电机组的可用容量与负荷预测的误差,以及贵州输电线路的可靠性诸因素,推导出合同电量与竞争电量交易比例,经过与南方区域电力市场目前运营规则规定的交易比例比较,该比例是合理的,可以规避电力市场价格波动等带来的风险。     

对外贸易对中国经济结构影响机制的实证分析

为充分说明对外贸易对中国经济结构的影响机制,在着重使用CGE模型的基础上,结合P ro jectL ink模型中劳动力供求与价格影响决定模块,综合考察传导因素—价格作用下比较优势的差异导致经济结构的形成,以及开放条件下对外贸易对经济结构的影响,充分体现价格因素在整个宏观体系中的传导作用.     

基于CARR模型的交易量与股价波动性动态关系的研究

股市交易量与股价变化的关系就一直是学术界与实务界所共同关心的主题。基于Chou(2005)提出的CARR模型对两者的动态关系问题进行了研究。首先分析了作为量价关系理论基础的混合分布假说理论在CARR模型中的适川性,进而基于混合分布假说理论对我国上证综合指数、深证成份指数以及随机抽取的十只个股进行了量价关系的实证检验。研究发现:混合分布假说理论同样适用于CARR模型,这证实了股价波动性的CARR效应的存在。实证的结果也证实了CARR模型无论是对于股票指数还是单只股票交易量都具有了良好的解释作用。因此,CARR模型与GARCH模型相比,在交易量与股价波动关系动态关系的研究领域可以得到更为稳健的结果。