关键词： process control   optimization  

摘要： Economic model predictive control (EMPC) is a control scheme that combines real-time dynamic economic process optimization with the feedback properties of model predictive control (MPC) by replacing the quadratic cost function with a general economic cost function. Almost all the recent work on EMPC involves cost functions that are time invariant (do not explicitly account for time-varying process economics). In the present work, we focus on the development of a Lyapunov-based EMPC (LEMPC) scheme that is formulated with an explicitly time-varying economic cost function. First, the formulation of the proposed two-mode LEMPC is given. Second, closed-loop stability is proven through a theoretical treatment. Last, we demonstrate through extensive closed-loop simulations of a chemical process that the proposed LEMPC can achieve stability with time-varying economic cost as well as improve economic performance of the process over a conventional MPC scheme. (c) 2013 American Institute of Chemical Engineers AIChE J 60: 507-519, 2014

关键词： Agriculture   Algorithms   Applied mathematics   Aquaculture   Biology   Biostatistics   Ecological economics   Ecology   Economic epidemiology   Epidemiology   Fish farming   Fisheries science   Marine biology   Marine ecology   Marine monitoring   Mathematics   Population biology   Population modeling   Research Article   Statistics  

摘要： Management of catches, effort and exploitation pattern are considered the most effective measures to control fishing mortality and ultimately ensure productivity and sustainability of fisheries. Despite the growing concerns about the spatial dimension of fisheries, the distribution of resources and fishing effort in space is seldom considered in assessment and management processes. Here we propose SMART (Spatial MAnagement of demersal Resources for Trawl fisheries), a tool for assessing bio-economic feedback in different management scenarios. SMART combines information from different tasks gathered within the European Data Collection Framework on fisheries and is composed of: 1) spatial models of fishing effort, environmental characteristics and distribution of demersal resources;2) an Artificial Neural Network which captures the relationships among these aspects in a spatially explicit way and uses them to predict resources abundances;3) a deterministic module which analyzes the size structure of catches and the associated revenues, according to different spatially-based management scenarios. SMART is applied to demersal fishery in the Strait of Sicily, one of the most productive fisheries of the Mediterranean Sea. Three of the main target species are used as proxies for the whole range exploited by trawlers. After training, SMART is used to evaluate different management scenarios, including spatial closures, using a simulation approach that mimics the recent exploitation patterns. Results evidence good model performance, with a noteworthy coherence and reliability of outputs for the different components. Among others, the main finding is that a partial improvement in resource conditions can be achieved by means of nursery closures, even if the overall fishing effort in the area remains stable. Accordingly, a series of strategically designed areas of trawling closures could significantly improve the resource conditions of demersal fisheries in the Strait of Sicily,

关键词： 新建住宅价格   空间效应   空间计量经济模型  

摘要： 基于郑州市近几年新建住宅微观数据,首先分析了新建住宅价格的空间相关模式及空间集聚性,发现郑州市新建住宅价格存在着明显的空间依赖性,并且空间相关模式具有区域异质性;通过空间效应检验判断,空间滞后效应较为明显,对于新建住宅价格的影响在空间维度上非常显著,也是最重要的因素。通过空间计量模型分析发现,空间溢出效应和交通可达性也是不容忽视的影响因素;在模型选取上,从拟合优度和极大似然值等判断,空间杜宾模型(SDM)是四种模型中拟合最优的模型;最后本文建议政府部门在进行房地产政策选择和价格调控措施时,必须充分考虑到空间作用机制对于新建住宅价格的空间异质效应。

关键词： 利率管制   金融体系   投资效率   扭曲   金融改革   非正规金融   市场化发展   经济模型  

摘要： 由于央行利率管制，使我国的金融体系出现金融扭曲的现象。通过构建两种金融资本经济模型，对这种扭曲的金融结构能够有效的改善，降低非正规金融占有率，提高投资效率。在金融改革的过程中，利率的市场化发展是改革的必然选择。

关键词： 农民纯收入   预测   灰色GM(1,1)模型   多元线性计量经济模型  

摘要： 针对单一预测模型精度不高以及预测结果不能体现经济变量关系的不足,将灰色GM(1,1)模型与多元线性计量经济模型加以耦合,建立了灰色多元线性计量经济模型,并利用该模型对湖南省农村居民人均纯收入进行了预测。灰色多元线性计量经济模型的预测精度不仅明显高于单一的灰色GM(1,1)模型和多元线性回归模型,而且预测结果也能体现经济变量之间的关系。预测结果表明,未来几年湖南省农村居民人均纯收入逐年增长,但增长的速度较为缓慢。最后,给出了几点调控湖南省农村居民收入差距的建议。

关键词： 时滞动力系统   泛函微分方程   稳定性   周期解   金融模型   生物模型   全局存在性  

摘要： 时滞微分方程作为泛函微分方程的一个重要分支，广泛地应用于刻划流体力学，种群生态学，生物学，经济学及交叉学科问题。分支问题通常用于研究结构不稳定的非线性系统，是微分方程中的一个重要课题。时滞微分方程的稳定性和分支问题的研究具有理论和实际意义。本文着手于研究时滞微分方程在经济和生物模型中的应用，研究结果如下:\n 第一章，主要介绍了一些基本的定义和定理。\n 第二章，展示了基于经济理论的具有双时滞的价格微分方程的动力学行为。主要目的是为双时滞价格模型中未开发的领域提供了一个研究方法。首先，我们通过考虑需求函数为开口向下的二次函数，且供给和需求都依赖于过去和现在的价格修改了传统的价格模型，从而建立了具有双时滞的价格模型。其次，考虑只有一个时滞的情形获得了相应的稳定区间，然后把另一个时滞作为参数，从而研究了模型的线性稳定性和局部Hopf分支。最后，我们利用规范型理论和中心流形定理推导出计算Hopf分支方向和分支周期解的稳定性的公式。\n 第三章研究了具有时滞的金融模型的动力学性质。本章主要目的是研究一个金融模型Hopf分支，为进一步探讨做好准备工作。我们将时滞当作分支参数研究其动力学行为。首先，研究了系统的局部稳定性和Hopf分支的存在性从而揭示了引起复杂动力学现象的原因。最后，利用规范型理论和中心流形定理，我们得出一个Hopf分岔的稳定性和方向的计算公式。\n 第四章我们研究了基于SIR流行病模型引入非线性发生率和时滞建立了禽流感病毒的传播模型。我们将时滞当作分支参数研究了模型的动力学行为。首先，研究了模型的局部稳定性和Hopf分支的存在性，当时滞经过一系列的临界值时产生了Hopf分支。用第二章中相似的方法研究了Hopf分支的周期解的稳定性和方向的计算公式，最后证明了周期解的全局存在性。

关键词： Transportation scenarios   CO2 (Carbon dioxide) emission mitigation   Hydrogen   Energy-economy modeling   BEVs (Battery electric vehicles)   Mobility demand reduction  

摘要： Decarbonizing transport will be necessary to limit global warming below 2 degrees C. Due to persistent reliance on fossil fuels, it is posited that transport is more difficult to decarbonize than other sectors. To test this hypothesis, we compare long-term transport energy demand and emission projections for China, USA and the world from five large-scale energy-economy models. We diagnose the model's characteristics by subjecting them to three climate policies. We systematically analyze mitigation levers along the chain of causality from mobility to emissions, finding that some models lack relevant mitigation options. We partially confirm that transport is less reactive to a given carbon tax than the non-transport sectors: in the first half of the century, transport mitigation is delayed by 10-30 years compared to non-transport mitigation. At high carbon prices towards the end of the century, however, the three global models achieve deep transport emission reductions by >90% through the use of advanced vehicle technologies and low-carbon primary energy;especially biomass with CCS (carbon capture and sequestration) plays a crucial role. The extent to which earlier mitigation is possible strongly depends on implemented technologies and model structure. Compared to the global models, the two partial-equilibrium models are less flexible in their reaction to climate policies. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Representative Agent Model   Production Function   Current Account   Trade Balance   Grey Systems  

摘要： The work is a development of our earlier studies containing empirical application of models with representative agent. The extensions developed in this paper consist of the following: the introduction of the labor market via the use of labor as the second production factor, the use of the GM(1,1) algorithm in order to adjust the capital and labor data series and to compute grey Cobb-Douglas production function, and finally the comparison of the results obtained applying the model to the actual data and the grey data. The grey production function is estimated using GM(1,1) adjusted statistical series of the GDP, capital stock and labor data. For the two variants we computed the predictions of the indicators: real GDP, consumption, government expenditures, trade balance, and burden of debt.

关键词： Integrated Assessment   Climate   Energy   Water   Green Economy  

摘要： At the Rio   +   20 Conference in 2012, the United Nations declared that a “green economy in the context of sustainable development” is a chance for economic development in the institutional framework of sustainable development [1] . The German Government supports the UN approach for a green economy [2] . We intend to analyse German society and its CLEW systems (climate, land, energy and water) because the UN defined the latter as key issues in the green economy [1] . Against this background, we developed an integrated sustainability assessment framework to monitor and measure the development of the green economy in Germany based on the EU Strategic Environmental Assessment (SEA) Directive framework [3] , [4] . Whether sustainable development has been achieved in Germany and its CLEW systems will be determined by an analysis of all quantifiable indicators of the enlarged German sustainability strategy [5] . Our measuring approach aggregates the indicators of the German sustainability strategy into one index [6] . Our sustainability gap index reveals the heterogeneity of the development of the sustainability indicators of the German sustainability strategy. The index calculates the degree to which sustainability is achieved and our integrated assessment approach enables us to identify contradictions and similarities between the CLEW systems and the overall German socio-economic system.

关键词： 土地管理   耕地非农化   经济增长质量   库兹涅茨曲线   空间计量经济模型  

摘要： 研究目的:分析中国耕地非农化与经济增长质量之间是否存在库兹涅茨曲线并进行验证。研究方法:空间计量经济模型。研究结果:常规面板模型和空间面板模型的结果均显示,中国耕地非农化与经济增长质量之间存在明显的倒"U"型关系,验证了"耕地库兹涅茨曲线"假说,且当经济增长质量(全要素生产率指数)达到1.4087时,耕地非农化与经济增长之间的矛盾将逐渐减小;区域间的耕地非农化确实具有较强的正向空间相关关系,即相邻地区耕地非农化数量变动1%,会导致本地区耕地非农化数量平均变动0.1627%。研究结论:系统地识别、评估区域间耕地非农化与经济增长质量的空间联动性,对于促进区域间耕地总量动态平衡具有十分重要的理论和现实意义。