关键词： URBAN economics   URBAN growth   LAND use   REAL property   URBAN policy  

摘要： We review the usefulness of urban spatial economic models of land use change for the study and policy analysis of spatial land use-environment interactions. We find that meaningful progress has been made in econometric and monocentric models extended to account for multiple sources of spatial heterogeneity and in the development of general equilibrium models with spatial dynamics. Despite these advances, more work is needed in developing models with greater realism. Most agent-based computational models of urban land use change currently lack economic fundamentals, but provide a flexible means of linking microlevel behavior and interactions with macrolevel land use dynamics. In combination with empirical methods to identify parameters, this framework provides a promising approach to modeling spatial land use dynamics and policy effects.

关键词： 生物经济模型   奇异诱导分岔   冲动行为  

摘要： 本文问题的奇异诱导分岔和一类的生物经济模型的冲动行为是有区别的理论代数方程调查。在奇异诱导分岔和冲动行为时发现的收入等于总成本。

关键词： 平滑转移模型   非参数模拟最大似然估计   滑动窗宽算法  

摘要： 本文提出使用核估计的方法构造平滑转移模型(STR)的非参数模拟最大似然估计(NPSML),给出了NPSML估计量的构造方法、渐近性质以及相应的核函数和窗宽的选择准则,并利用滑动窗宽算法对估计量的构造过程进行了改进。通过Monte Carlo实验证明,该方法是可靠的,并且当误差项存在序列相关时,此种估计量是稳健的。

关键词： 绿色物流   共同配送   费用分摊  

摘要： 共同配送作为绿色物流的重要组成部分,能够产生很大的经济效益。文章主要针对绿色物流管理情况下的共同配送的利益分配与费用分担问题进行研究。运用博弈论的基本原理建立经济模型,并结合企业实际对模型加以运用,最后对实例研究的结果进行了分析。从分析结果中可以看出,在各种不同配送方案下,各企业支付的共同配送费用均比单独配送的费用有所降低。

关键词： 经济学理论   精神   动物   理论著作   科普读物   经济模型  

摘要： 《动物精神》，单从书名看，像是一本科普读物．其实这是一本经济学理论著作。在一般人的概念中，经济学是严肃的，经济学理论多半也是生涩枯燥的．是通过严谨的经济模型推导出来的，但这本书要感性得多。

关键词： 研发投资   跨国公司   内生因素   空间计量经济模型  

摘要： 研发投资的空间集聚有利于溢出知识、节约成本、降低风险、共享资源。以中国省市为空间样本,采用空间自相关Moran指数及集聚分析的空间计量经济学方法,研究了在华跨国公司研发投资的空间溢出效应及区位决定因素。结果发现,在溢出空间性等集聚内生因素作用下,中国省域跨国公司研发投资行为在空间分布上存在交互作用,表现为明显的区域投资集聚现象;在形成空间集聚的各因素中,除市场规模、人才资源等需求和供给因素外,集聚因素本身也有重要影响。

关键词： 时间滞后   脉冲跳跃   稳定性分析   Hopf分支   经济模型   金融系统  

摘要： 时滞和脉冲是经济数学模型中的两个重要的影响因素，对具有时滞和脉冲的经济动态系统的研究是微分动力学领域的前沿课题之一，一些经济现象不能纯粹的利用常微分方程来描述，在实际的生产生活中，并不像数学表达式一样有规律，往往事物表现一种时间滞后和脉冲跳跃现象.事实上，用时间延迟和脉冲扰动可以更有效地描述现实的经济体系.本文利用时滞和脉冲扰动刻画了一些经济模型的运行规律，主要完成了以下工作：\n 第二章，研究了一个具有时滞物价微分方程模型的稳定性和Hopf分支问题.利用Hopf分支定理，规范性理论及其中心流行定理，通过选择时滞作为分支参数，分析线性化系统的特征方程，得到了系统平衡点的稳定性和Hopf分支存在的充分条件，给出了确定Hopf分支方向和分支周期解的稳定性的计算公式.\n 第三章，提出了一个具有分布时滞的金融系统，本文研究了这个系统的复杂的动态行为，诸如：周期，拟周期，Hopf分支，混沌吸引子等，通过研究，对商业市场的周期性及其不规则性提供了很好的解释；然后又对这个金融系统进行了脉冲控制，利用脉冲微分方程理论，对这个金融系统脉冲控制至稳定的平衡点进行了研究，得到了带有变化脉冲区间的一个金融系统的稳定性的充分条件.通过脉冲控制，在某种程度上，我们能够有效地控制商业市场健康有规律的运行.\n 第四章，鉴于企业集群类似于生物生态系统，他们之间存在很多相似的特征，本章提出了一个基于生态学理论具分布时滞和脉冲收获的企业捕食-食饵模型，通过利用Floquet理论，小振幅扰动方法和脉冲微分方程比较定理，我们得到了企业破产和持久存在的阈值，并且获得了一些有经济意义的理论结果.也证明了最终影响企业命运的一些因素.

关键词： Agriculture   Agrochemicals   Atmospheric Agriculture   Atmospheric pollution models   Climate and crops   Climate models   Climatic changes   Crops   Economics   Emissions   Environmental economics   Fertilizers   Greenhouse gases   Intergovernmental Panel on Climate Change   Livestock   Nitrous oxide   Soil   Taxation   agricultural land   agriculture   farms   guidelines   mitigation   soil types   France   Livestock   economics   environmental economics   tax   Agrochemicals   Farmland   agriculture   emission factor   Intergovernmental panel on climate change   fertilizers   nitrous oxide   SOIL TYPES   climate models   Taxation   Greenhouse gases  

摘要： Agricultural soils are a major source of atmospheric nitrous oxide (N2O), a potent greenhouse gas (GHG). Because N2O emissions strongly depend on soil type, climate, and crop management, their inventory requires the combination of biophysical and economic modeling, to simulate farmers' behavior. Here, we coupled a biophysical soil-crop model, CERES-EGC, with an economic farm type supply model, AROPAj, at the regional scale in northern France. Response curves of N2O emissions to fertilizer nitrogen (Nf) inputs were generated with CERES-EGC, and linearized to obtain emission factors. The latter ranged from 0.001 to 0.0225 kg N2O-N kg (-aEuro parts per thousand 1) Nf, depending on soil and crop type, compared to the fixed 0.0125 value of the IPCC guidelines. The modeled emission factors were fed into the economic model AROPAj which relates farm-level GHG emissions to production factors. This resulted in a N2O efflux 20% lower than with the default IPCC method. The costs of abating GHG emissions from agriculture were calculated using a first-best tax on GHG emissions, and a second-best tax on their presumed factors (livestock size and fertilizer inputs). The first-best taxation was relatively efficient, achieving an 8% reduction with a tax of 11 a,not sign/ t-CO2-equivalent, compared to 68 a,not sign/t-CO2 eq for the same target with the second-best scheme.

关键词： Soil erosion   Agricultural policies   Bio-economic model   Cost-effectiveness analysis   USLE  

摘要： As agricultural policies affect land use, they have effects on the amount of soil erosion in agricultural regions through changes of the economic conditions of agricultural production. Prices of inputs and outputs, regulations and incentives can change, forcing or encouraging farmers to adopt new crop rotations. This paper shows how a bio-economic model can be used to describe and estimate the effects of policies on agricultural production and the risk of soil erosion at the example of a region in North-Eastern Germany. The model uses both an assessment tool that is based on a fuzzy-logic approach for the estimation of soil erosion risk of cropping practices, and a linear programming model, that simulates farmers' economic behaviour under the assumption of gross margin maximisation being the main goal of farmers' actions. The analysed policy options were both a targeted and an untargeted incentive programme for reduced tillage, and a restriction option where high erosive crops are not allowed on high erodible field types. The results show that policy changes can have an impact on soil erosion. Furthermore, soil conservation policies are shown to have different levels of efficiency in terms of reduced soil erosion related to the costs of the policy. In the case of this study. a restriction option was more efficient than the incentive options. The results of such simulations can serve as a decision support for the development of soil conservation policies and help to foresee the effects of general changes of agricultural policies. (C) 2008 Elsevier Ltd. All rights reserved.