Some Illustrations Of Chaos In Commodity Models
Some Illustrations Of Chaos In Commodity Models
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商品模型中混沌的一些例证
DOI：
10.1111/j.1477-9552.1993.tb00249.x
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Burton
中科院分区：
文献类型：
--
作者：
M. Burton
本文建立了三个表现混沌行为的商品模型。选择的例子是一个需求系统和两个蛛网供给和需求模型。后者与标准形式的不同之处在于，它们包括风险规避和价格预期形成的新规范。模型的仿真突出了混沌的三个含义：即使模型内的外生变量保持不变，这样的系统也会产生复杂的时间路径；模拟的时间路径对变量的起始值和参数值非常敏感；系统的平均行为对参数和外生变量值极为敏感。“临界敏感”是指参数或起始值的微小变化会导致模型中变量的时间路径发生实质性变化。这些结果表明，如果真实的商品部门可以被描述为混沌系统，那么对这些部门进行预测和政策分析的能力将受到严重削弱。
This paper develops three commodity models which exhibit chaotic behaviour. The examples chosen are a demand system and two cobweb supply and demand models. The latter differ from the standard forms in that they include risk aversion and a new specification for the formation of price expectations. Simulation of the model highlights three implications of chaos: such systems generate complex time-paths even if the exogenous variables within the model are held constant; the simulated time path is critically sensitive to the starting value of variables, and parameter values; and the average behaviour of the system is critically sensitive to parameter and exogenous variable values. ‘Critically sensitive’ means that very small changes in parameter or starting values leads to substantial changes in the time paths of the variables in the model. These results suggest that if real commodity sectors can be characterised as chaotic systems, then the ability to conduct forecasting and policy analysis of such sectors will be severely curtailed.