Nonlinear portfolio selection using approximate parametric Value-at-Risk

As the skewed return distribution is a prominent feature in nonlinear portfolio selection problems which involve derivative assets with nonlinear payoff structures, Value-at-Risk (VaR) is particularly suitable to serve as a risk measure in nonlinear portfolio selection. Unfortunately, the nonlinear portfolio selection formulation using VaR risk measure is in general a computationally intractable optimization problem. We investigate in this paper nonlinear portfolio selection models using approximate parametric Value-at-Risk. More specifically, we use first-order and second-order approximations of VaR for constructing portfolio selection models, and show that the portfolio selection models based on Delta-only, Delta–Gamma-normal and worst-case Delta–Gamma VaR approximations can be reformulated as second-order cone programs, which are polynomially solvable using interior-point methods. Our simulation and empirical results suggest that the model using Delta–Gamma-normal VaR approximation performs the best in terms of a balance between approximation accuracy and computational efficiency.     

高职物流管理专业实践教学体系运行机制探讨

高职物流管理专业培养的物流人才的核心竞争力在于具有很强的技术性、职业性。科学有效的实践教学体系运行机制是保证高质量技术性物流人才培养的摇篮。本文分析了当前高职物流管理专业实践教学体系运行机制存在的主要问题,并提出了建立高职物流管理专业实践教学体系运行机制的措施方法。     

华庆油田产能建设“1822”提单产系统工程应用实践

针对华庆超低渗油田实际情况,在总结、借鉴、改进、实践、提高的基础上,研究编制并科学组织以实现1个提单产目标、实施8个子系统工程及严格控制相关22个应用节点为主要内容的产能建设"1822"提单产系统工程,获得了理想的提高单井产量效果。该提单产系统工程方法对其他超低渗油田提升新井产量具有实际指导意义。     

Data Watch on China's Foreign Trade and Investment in H1, 2011

Foreign trade According to statistics of the Customs, China's exports and imports in the first half of the year reached US$1.70367 trillion, up 25.8 percent over the same period last year.Specifically, Exports was USS874.3 billion, up 24%; imports US$829.37 billion, up 27.6%.The trade surplus stood at US$44.93 billion, down 18.2%.In June alone, China's imports and exports reached US$301.69 billion, up 18.5% year on year.In detail, exports stood at US$161.98 billion, up 17.9%; imports US$139.71 billion, with a trade surplus of US$22.27 billion, an increase of 10.3% over last year.     

酸性蚀刻废液中铜的形态分布及电化学行为

在氯化物体系中，Cu^＋、Cu^2＋均能与Cl^-形成多种形态的配合物，存在形态及分布与溶液中各离子浓度有关。由于各种配合物的稳定性不同，致使Cu^＋、Cu^2＋氯化物的溶解度及电极电位也不同。对酸性蚀刻废液中铜的存在形态、电化学行为、以及采用隔膜电解法回收工艺的可行性进行了分析。     

后危机时代美国外贸政策的调整及其影响

国际经济危机后,美国政府大力调整外贸政策,确定国家出口战略,力图提升国际竞争力,文章对美国外贸政策调整的基本内容、背景及影响进行了分析,指出了美国政策调整的隐形贸易保护主义倾向,并认为它无益于美国国内产业竞争力的提升。     

China Sports Goods Industry:Big but Not Strong

China,though not the largest consumer market of sports commodities,has 20,000-plus producers of sports goods.A reshuffle of the industry to retain the strong ones and eliminate the weak is going on,said Ma Jilong,vice-Chairman of China Association of Sports Goods Industry,during the 30th China Sports Show held from May 17 to 20 in Beijing. Asked about the unique features of this expo,Ma said that it has grown from a pure show of sports goods into one that features sports culture,financing,release of trade standards,and auction of sports collection.Yao Ming attended the show,as an investor instead of a sportsman.Yao said he was interested in some creative mass sports programs initiated by young entrepreneurs. The first day of the show received 20,000 visitors,most of whom are professionals in the industry.There are also foreign visitors,mainly from India,Pakistan,Turkey and the Middleeast.     

The impact of perceived security and consumer innovativeness on e-loyalty in online travel shopping

ABSTRACT

This study investigates the impacts of perceived security and consumer innovativeness on online travel shopping. A survey questionnaire was used to collect data and a total of 283 questionnaires were used for data analysis. The mechanism of perceived security and consumer innovativeness was then identified. The study results indicate that: (1) higher perceived security increases the perception of website image and trust; (2) consumers with a higher level of innovativeness tend to trust travel websites; (3) website image has a mediating effect between perceived security and trust; and (4) trust has a mediating effect between website image and e-loyalty.     

政府管控一般目标、总量结构和管控基本范畴

政府宏观经济管控目标具有多重性,包括保持社会总供给与总需求的平衡,促进经济再生产各环节及各产业、地区间的协调,不断提高人民生活水平调节社会分配,保护生态环境和自然资源,实现经济长期发展的良性循环和社会进步等,还包括经济目标"效率"和社会目标"均等"。宏观经济管理、调控和干预是三个既有联系又有区别的概念,而管控应当说包涵了三方面内容。管控的基本内容和手段实际也是市场机制调节功能的有机组成,客观上要求宏观经济调节机制必须通过市场机制起作用。     

商业退回逆向物流网络优化模型研究

针对如何使商业退回成本最小,文中建立了一个数学模型,将商业退回逆向物流系统用一个由顾客、初始回收点和回收中心三类联结点以及它们之间的运输路线组成的网络来表示。为了验证模型的有效性,文中将模型应用于案例分析,最终根据模型求解结果为案例提供了一个具体的解决方案,对案例的求解结果进行了检验。