近三十年清代皖江流域经济史研究概况

清代是全国经济发展的一个重要历史时期,区域经济的发展和大规模的商品流通是其显著特征,长江流域亦不例外。在清代,随着全国经济格局的变动,长江流域逐渐形成了以粮食为主要商品的“东西贸易”体系,沿江各省份的经济联系日益紧密。作为皖省的经济重心,皖江流域也以自身的方式参与其中,发挥着承东启西的作用。历史是现实世界的人们进行创造活动的客观基础和初始条件,     

我国森林抚育经营中存在的问题及改进对策探讨

从我国森林抚育经营管理的实际情况出发,分别对经营管理措施、经费投入和理论技术体系等方面,分析了森林抚育经营中存在的主要问题,并针对存在的主要问题从森林经营抚育的指导思想、经营管理方针、经费保障和理论技术体系等方面提出了我国森林抚育经营的改进对策,以期为加强我国抚育经营管理提供参考。     

Modeling strategic group dynamics: A hidden Markov approach

With competition playing a critical role in market-based strategic planning and implementation, identifying and understanding competiton and competitive dynamics has become critical. In this vein, the strategic groups perspective has emerged as a powerful means to understand such competitive phenomena. Empirical approaches to model competitive dynamics within the strategic groups framework, however, have been piece meal as researchers typically resort to distinct sequential analysis by time period. To overcome the limitations of these simplistic approaches, we develop a hidden Markov model to study strategic group (competitive) dynamics. In this approach, we explicitly account for competitive dynamics over time by modeling strategic group memberships as latent states that follow a first-order Markov process. Thus, we explictly model the notion that firms adopt their strategy for the next time period based on their current strategy and respective outcomes. We illustrate the model with longitudinal data from COMPUSTAT on 63 public banks from the tri-state region of NY-OH-PA. The results show the proposed model to be superior to a number of viable alternative approaches that have been suggested in the literature. We find the existence of three strategic groups: the leveraged group has low current assets compared to current liabilities, high debt to equity, and high total borrowing to assets. The lending group consists of the largest banks that focus on lending with high ratios of gross loans to securities and gross loans to deposits. The balanced group has the largest number of banks where the values of the financial and product ratios are intermediate compared to the leveraged and lending groups. The asymmetries in the switching probabilites are also evident as there seems to be a higher probability of switching into the balanced group than switching out of this group. The switching probabilites are symmetric between the the leveraged and lending groups.     

基于权利分布风险测度的工程建设重大突发事件大群体应急决策方法

针对大型工程项目突发事件应急决策参与者权利分布导致的风险,提出了一种大群体风险应急决策方法。首先,利用信息熵理论,提出了一种测量大群体决策风险的测度模型;其次,对参与决策的大群体在决策过程中由于权利分布引起的风险进行了定量计算;然后,利用风险大小确定最终偏好信息的集结结果,对应急方案进行排序选优。最后,通过工程项目建设中仓库爆炸突发事件案例分析,验证了该方法的有效性。     

食物消费结构升级对农业碳排放的动态影响机制研究

[目的]探寻主要食物消费结构与农业碳排放之间的动态关联机制。[方法]基于1990—2015年面板数据,通过VAR模型进行研究。[结果]结果显示食物消费结构升级与农业碳排放确实有着一定的关联性,且存在一定的滞后性,但其影响程度和方向因食物种类而异。[结论](1)从影响方向看,农业碳排放对肉禽类、奶类等动物性食物消费和粮食、蔬菜、食用植物油等植物性食物消费变动的冲击响应方向基本相反,这主要是由动物性食物和植物性食物的替代性导致;农业碳排放对食物消费变化冲击的响应方向呈正负交替变化,且随着时间的推移而趋于平缓,主要是由于农产品供求的收敛型\"蛛网\"变动特点引起。(2)从响应时间看,农业碳排放变动对植物性食物消费冲击响应更为迅速,主要是由于动物类食物调整生产周期明显长于植物类食物产品;以植物性食物消费代替动物性食物消费的方式在短期内(3～4年以内)确实可以一定程度上降低碳排放,但是长期看来效果并不明显;所有食物消费变动对农业碳排放的冲击效应在8～9期以后均逐渐消失,说明食物消费结构的变动对农业碳排放的影响持久,农业碳减排任务不可能在短期内一蹴而就,而需要长期而持续的努力。(3)从影响程度看,方差分解结果表明,对农业碳排放变动的影响贡献最大的是其自身,说明农业碳排放基数庞大,减排工作任务艰巨,尽管肉禽类食物消费导致的碳排放量比重较大,但研究期间农业碳排放变动的并不是主要由这类食物消费的变化导致,而是由植物性食物消费变化导致。研究结果为在满足居民食物消费需求的前提下降低农业碳排放、发展低碳农业提供一定的依据。     

发展旅游业——新疆社会经济发展的必然选择

旅游是一种具有重大经济与文化意义的活动,它的产生和发展紧随社会前进的步伐。近年来,随着人们收入的增长和消费水平的提高,节假日外出旅游成为时尚。目前,旅游业是我国的重要产业。在我国的很多地区,旅游业已成为增加经济收入、改善产业结构、提高人们的现代意识、推动区域经济和社会进步的重要产业。新疆地区少数民族众多、地域辽阔,加上历史文化悠久,孕育了丰富的自然旅游资源及人文旅游资源,在全国具有旅游资源的比较优势,因此发展旅游业必将带动新疆地区社会经济的全面发展。     

基于管理效率的民营企业内部管理模式选择

本文从管理效率的视角研究民营企业在家族式管理与职业化管理中的选择问题.本文运用威廉姆森的理论框架与博弈论的原理证明职业化管理成本高于家族式管理成本,但另一方面,又论证了职业化管理的管理收益也高于家族式管理,管理效率随管理职业化水平的变化而定,找出了管理职业化水平的最优点,分析了管理职业化水平与企业规模的匹配问题,提出了政府在提升企业管理职业化水平方面应采取的措施.     

R-optimal designs for multi-factor models with heteroscedastic errors

In this paper, we consider the R-optimal design problem for multi-factor regression models with heteroscedastic errors. It is shown that a R-optimal design for the heteroscedastic Kronecker product model is given by the product of the R-optimal designs for the marginal one-factor models. However, R-optimal designs for the additive models can be constructed from R-optimal designs for the one-factor models only if sufficient conditions are satisfied. Several examples are presented to illustrate and check optimal designs based on R-optimality criterion.     

Corporate governance in family-controlled firms in Taiwan

This paper examines the effects of ownership structure and board characteristics on performance in publicly traded Taiwanese firms that are controlled by founding families. Results show that when shares are owned by institutional investors, particularly foreign financial institutions, firms perform better. However, where families are the major shareholders, this is not the case. In addition, boards that are independent of the financial interests of the founding family have a positive impact on performance, whether measured by accounting ratios, operating performance or the stock market. (JEL: P52, G32)