ENHANCEMENT OF THE APPLICABILITY OF MARKOWITZ'S PORTFOLIO OPTIMIZATION BY UTILIZING RANDOM MATRIX THEORY

The traditional estimated return for the Markowitz mean-variance optimization has been demonstrated to seriously depart from its theoretic optimal return. We prove that this phenomenon is natural and the estimated optimal return is always       times larger than its theoretic counterpart, where       with  y  as the ratio of the dimension to sample size. Thereafter, we develop new bootstrap-corrected estimations for the optimal return and its asset allocation and prove that these bootstrap-corrected estimates are proportionally consistent with their theoretic counterparts. Our theoretical results are further confirmed by our simulations, which show that the essence of the portfolio analysis problem could be adequately captured by our proposed approach. This greatly enhances the practical uses of the Markowitz mean-variance optimization procedure.     

解读元杂剧中的鬼魂托梦情节

元杂剧中鬼魂托梦情节出现频率较多,这种独特的艺术现象不仅使戏曲情节妙趣横生,还使作品的思想意义得到深化。总的来说,元杂剧中的鬼魂托梦情节大都是因为生前的种种情感纠葛,主要包括冤情、亲情、友情、爱情和君臣之情。     

现货交易所改进红茶业流通效率研究

交易所市场是商品交易中心发展的最高形式。主动建立红茶现货交易所将有助于提升整个产业的流通效率,促进我国从红茶贸易大国向贸易强国转型。在讨论农产品流通效率研究不足的基础上,本文聚焦近年来期货交易所的实践,从实行现货合约延期交易、建立风险控制规则、实施投机规范机制三个方面提出建立红茶交易所的构想,指出交易所市场能够确定价格形成机制、促进区域性市场对接融合、提供信用担保,从而有效地清除阻止红茶流通效率提升的障碍。     

跨国公司跨国经营理论的发展趋势评析

该文认为:跨国公司战略演变推动了跨国公司跨国经营理论发展。二次大战后,跨国公司实现了从复合一体化、外源归核化到合作竞争的战略演变,对跨国公司理论的发展提出了新的要求。跨国公司跨国经营理论将更注重目标导向、区位选择和利益机制分析。     

浮动汇率制度有助于经常账户的调节吗?——基于双倍差分法的实证检验

本文运用双倍差分法,分别选择20世纪90年代亚洲金融危机和20世纪70年代布雷顿森林体系的解体两个事件作为"自然实验",实证研究汇率制度与经常账户调节的关系。研究表明,相对于固定汇率制度,浮动汇率制度未能显著地促进经常账户的调节。通过让经常账户盈余国由固定汇率制度调整为浮动汇率制度的做法不会改善全球性经常账户失衡问题。     

政府行为下创新要素流动及其空间溢出效应研究

基于2000-2018年中国内地31省市面板数据,采用固定效应分析法探讨政府行为与创新要素流动的内在机理,运用空间杜宾模型探究两者之间是否存在空间溢出效应。结果发现：就全国而言,地方政府竞争行为对R&D人员和R&D资本要素流动存在倒U型影响,且地方政府竞争与政府支持、政府支持与政府房地产投资偏好行为可以协同发力促进创新要素流动;另外,地方政府竞争和政府支持能够促进周边地区创新要素流动,而政府房地产投资偏好仅能影响周边地区R&D人员流动。在分区域研究中,东部地区3种地方政府行为对创新要素流动均存在倒U型影响,中部地区政府房地产投资偏好行为发挥倒U型作用,而政府竞争和政府支持行为发挥正U型作用;地方政府行为协同对中西部地区创新要素流动发挥正向促进作用,但在东部地区影响甚微。     

支持模式：农村妇女进村委——基于六种模式的比较与借鉴

当前农村妇女占农村总人口半数以上,经济政治女性化是农村今后相当长一段时间内的突出表现。农村妇女已成为村庄的核心力量,也是参与村委会选举、推动村委会选举制度不断完善的重要力量,其参与村民自治的重要性毋庸讳言,然而妇女进村委的比例很低。造成这种状况的原因众多,有经济制约论、文化不利论、角色冲突论、资源有限论、妇女弱势论等等,文章仅从选举制度层面加以阐释,通过对现有的具有代表性的六种模式的比较,找出各种模式的可借鉴之处。     

日本重大气候灾害的影响及其对策与技术措施研究

本文介绍了重大气候灾害对日本经济社会的影响,日本通过建立和完善各种应对措施,提高全社会的防灾减灾能力,积极利用遥感遥测技术,提高灾害气候的监测预警水平,积极开展长期气候研究,努力把握气候变化规律等有力措施,力求最大限度减少灾害损失.日本依靠科学技术提高灾害气候的监测预报水平,对我国防灾减灾提供了有益的启示.     

An empirical research of urbanization and urban-rural gap in China： 1952-2005

There are two important problems of urban-rural relationship in China nowadays： the accelerated urbanization process and an enlarged urban-rural gap. The researchers can be divided into two schools according to their emphasis. One emphasizes particularly the urban development, and the other pays attention to the urban-rural income gap. However, there is a very strong association between urbanization rate and urban-rural inequality. As far as it goes, there is a paradox between urbanization and urban-rural inequality in China. This main reason lies＇ in the different temporal and spatial scales chosen by the scholars. Making use of correlative analysis and wavelet method, this paper rethinks and sums up the commonly evolving characteristics and trends between urbanization and urban-rural gap from 1950s to now. There is an intensively positive correlation between urbanization and urban- rural consumption gap. In general, with the acceleration of urbanization, urban-rural gap of China has undergone three stages of cyclical fluctuations. The rapid urbanization results in the increase of urban-rural highly risky. In addition, the special stage of urbanization is the other reason that expands urban-rural gap.