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动态决策,多重均衡和复杂性

Dynamic Decisions, Multiple Equilibria and Complexity
课程网址: http://videolectures.net/eccs08_semmler_ddmeac/  
主讲教师: Willi Semmler
开课单位: 新社会研究学院
开课时间: 2008-10-17
课程语种: 英语
中文简介:
基于代理的模型通过动态系统表示多个代理之间的交互,通常会产生复杂和复杂的动态。我们可以通过强调经济主体具有记忆,形成期望,并在某个决策范围内的有意行为的指导来扩展这种类型的经济分析。但是,值得注意的是,代理商的决策和行动会改变经济环境并影响系统动态。在Lotka Volterra系统的背景下,代理的交互通常被设计为捕食者猎物,竞争和合作的交互。我们从这些类型的系统开始,并表明经济主体的决策可以被理解为一般系统动力学中的扰动术语。具有零时间范围的模型的动力学(其对系统动力学具有小的影响)通常可以被分析地研究并且作为具有更长时间范围的数值分析的起点。由于非线性,经常出现多重均衡,因此产生路径依赖性和复杂动态。我们通过使用具有灵活网格大小的动态编程来解决这些类型的模型,该网格大小可以捕获多个均衡,阈值和分岔行为。代理和多个吸引子的异质性预测结果的双峰分布,这可以使用马尔可夫转移矩阵凭经验验证。我们从资源经济学,发展经济学,投资理论,产业组织,不完善的资本市场,增长,分配和气候变化等方面给出了一些例子。我们给出了原型示例并说明了经济机制,其中可以发生这种复杂的动态,例如具有阈值和分叉行为的动态。这些类型的模型不仅可以通过实证检验,而且具有强烈的政策含义,因为政策可以将动态倾向于优越的均衡,并增加吸引域以获得更好的均衡。
课程简介: Agent-based models represent the interaction between a multiplicity of agents through dynamic systems, often giving rise to intricate and complex dynamics. We can extend this type of economic analysis by emphasizing that economic agents have memories, form expectations, and are guided by intentional behavior within the context of a certain decision horizon. However, it is important to note that the agents' decisions and actions change the economic environment and affect the system dynamics. The interaction of agents is often stylized as predator-prey, competitive and cooperative interactions in the context of Lotka-Volterra systems. We start with these types of systems and show that economic agents' decisions can be understood as a perturbation term in the general system dynamics. The dynamics of a model with zero time-horizon, which has small effects on the system dynamics, can often be studied analytically and taken as starting point for a numerical analysis with a longer time horizon. Since, due to nonlinearities, multiple equilibria frequently arise, this generates path dependency and complex dynamics. We solve these types of models by using dynamic programming with a flexible grid size that can capture multiple equilibria and threshold and bifurcation behavior. Heterogeneity of agents and multiple attractors predict a bimodal distribution of outcomes which can empirically be verified using Markov transition matrices. We give a number of examples from resource economics, development economics, investment theory, industrial organization, imperfect capital markets, growth, distribution, and climate change. We give prototype examples and illustrate economic mechanisms wherein such complicated dynamics, e.g., those with threshold and bifurcation behavior, can occur. These types of models can not only be empirically tested, but have strong policy implications in the sense that policy can tilt the dynamics toward superior equilibria and increase the domain of attraction for preferable equilibria.
关 键 词: 动态系统; 代理商; 马尔可夫转移矩阵
课程来源: 视频讲座网
最后编审: 2019-03-20:lxf
阅读次数: 42