关于加快发展现代循环农业的思考

现代农业在大发展的同时,出现了耕地减少、淡水短缺、生态环境恶化等资源环境承载能力问题,农业也要按照建设资源节约型、环境友好型社会的要求,以循环经济理念调整优化产业结构,加快推进农业科技创新,以"九节一减",资源综合循环利用和农业生态环境保护为重点,研发和推广应用农业节约型技术,减少农业面源污染、农业废弃物资源性等环保技术,促进农业可持续发展。     

低碳经济背景下缓解能源约束途径

在全球气候变暖的背景下,低碳经济的争夺战已悄然打响,过去那种依靠能源和环境的高投入、高污染、高消耗、低效率的粗放型增长方式已经难以为继。如何控制和减少中国碳排放、探索影响能源约束的因素、寻求缓解能源约束的途径已势在必行。通过构建模型对中国能源约束的影响因素进行了计量分析,研究结果显示在确保经济增长的速度和质量的前提下可以通过提升产业层次、改进能源利用效率以及优化能源贸易结构来缓解我国的能源约束,实现低碳经济背景下经济的可持续性发展．     

农村公共产品权益保障政策执行现状研究

农民权益保障问题是解决＂三农＂问题、构建社会主义和谐社会和建设社会主义新农村的关键所在。近年来,党中央出台了一系列保障农民享有公共产品权益的政策。调查发现,农村公共产品权益保障政策备受关注,但是相关政策的执行困难指数较高、政策执行部门存在较强的政策执行偏好等问题,亟待采取相应对策以优化政策执行,进一步加强农民权益保障。     

中国进口与经济增长关系研究

通过对中国1980—2009年进口总量及进口商品结构进行分析,发现进口贸易与经济增长之间存在长期稳定的关系,特别是工业制成品进口对经济增长有着显著的促进作用。在此基础上提出进一步扩大进口及优化进口结构的对策建议。     

群时延内均衡的模拟滤波器优化设计

为解决滤波器幅频特性算术对称性和通带内群时延波动之间的矛盾,提出了一种滤波 器群时延内均衡优化设计方法,即在网络综合法设计的滤波器电路基础上,将电路与时延均 衡器直接耦合,用最小二乘法使群时延特性逼近一个常数,然后利用无约束优化算法对整个 电路进行优化来降低通带内群时延波动。仿真结果表明,该方法不但能使滤波器幅频特性 算术对称且通带内的群时延特性波动较小,且阶数少、设计方法简单。     

顾客等待容忍度与银行排队服务系统的优化

本文通过实地调查发现,顾客最佳等待时间为8分钟,分析顾客等待心理可以提高银行顾客等待容忍度.利用相关数据进行统计检验,验证了客户到达率服从泊松分布,服务时间服从负指数分布,据此建立M/M/C单队多服务台模型.银行柜台费用优化模型需要权衡顾客成本与银行自身的运营成本,在不超过顾客能容忍的最长等待时间的前提下,银行应以最少...     

An evolutionary multi‐objective optimization of trading rules in call markets

We evaluate an agent‐based model featuring near‐zero‐intelligence traders operating in a call market with a wide range of trading rules governing the determination of prices and which orders are executed, as well as a range of parameters regarding market intervention by market makers and the presence of informed traders. We optimize these trading rules using a multi‐objective population‐based incremental learning algorithm seeking to maximize the trading volume and minimize the bid–ask spread. Our results suggest that markets should choose a small tick size if concerns about the bid–ask spread are dominating and a large tick size if maximizing trading volume is the main aim. We also find that unless concerns about trading volume dominate, time priority is the optimal priority rule. Copyright © 2011 John Wiley & Sons, Ltd.     

An Active Asset Management Investment Process for Drawdown-Averse Investors

The contribution of this article is to present an investment process that allows the asset manager to limit risk exposure to macro-factors – including expectations on correlation dynamics – whilst allowing for selective exposure to risk factors using factor-portfolios that emulate the risk and return profile of market micro-factors. The design of the process provides the ability to explicitely limit risk exposures to macro-factors based on forward-looking narratives allowing the investor to reflect – in the resulting active allocation – expectations of financial or systemic crises by, say, restricting the overall exposure to the credit macro-factor that includes the risk factor exposures (micro-level) arising, for example, from corporate and supranational spreads whilst simultaneously increasing the exposure to flight-to-safety macro-factors under a local or global crisis. This process is better suited to drawdown-averse investors that are willing to forgo some upside in order to effectively limit significant portfolio losses from crises, systemic or otherwise. In order to improve the optimization over the rugged solution space resulting from superimposing macro-factors' risk envelopes on the factor-portfolios' tracking error allocation, a genetic-algorithm-based optimization is proposed. Copyright © 2015 John Wiley & Sons, Ltd.     

Performance ratio-based coherent risk measure and its application

Utilizing a specific acceptance set, we propose in this paper a general method to construct coherent risk measures called the generalized shortfall risk measure. Besides some existing coherent risk measures, several new types of coherent risk measures can be generated. We investigate the generalized shortfall risk measure’s desirable properties such as consistency with second-order stochastic dominance. By combining the performance evaluation with the risk control, we study in particular the performance ratio-based coherent risk (PRCR) measures, which is a sub-class of generalized shortfall risk measures. The PRCR measures are tractable and have a suitable financial interpretation. Based on the PRCR measure, we establish a portfolio selection model with transaction costs. Empirical results show that the optimal portfolio obtained under the PRCR measure performs much better than the corresponding optimal portfolio obtained under the higher moment coherent risk measure.     

Portfolio optimization under a generalized hyperbolic skewed t distribution and exponential utility

In this paper, we show that if asset returns follow a generalized hyperbolic skewed t distribution, the investor has an exponential utility function and a riskless asset is available, the optimal portfolio weights can be found either in closed form or using a successive approximation scheme. We also derive lower bounds for the certainty equivalent return generated by the optimal portfolios. Finally, we present a study of the performance of mean–variance analysis and Taylor’s series expected utility expansion (up to the fourth moment) to compute optimal portfolios in this framework.