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第48行： − + − {{Main article|Causal loop diagram}} − − − − In the system dynamics methodology, a problem or a system (e.g., ecosystem, political system or mechanical system) may be represented as a [[causal loop diagram]].<ref>Sterman, John D. (2000). Business Dynamics: Systems Thinking and Modeling for a Complex World. New York: McGraw</ref> A causal loop diagram is a simple map of a system with all its constituent components and their interactions. By capturing interactions and consequently the feedback loops (see figure below), a causal loop diagram reveals the structure of a system. By understanding the structure of a system, it becomes possible to ascertain a system’s behavior over a certain time period.<ref>Meadows, Donella. (2008). Thinking in Systems: A Primer. Earthscan</ref> − − In the system dynamics methodology, a problem or a system (e.g., ecosystem, political system or mechanical system) may be represented as a causal loop diagram. A causal loop diagram is a simple map of a system with all its constituent components and their interactions. By capturing interactions and consequently the feedback loops (see figure below), a causal loop diagram reveals the structure of a system. By understanding the structure of a system, it becomes possible to ascertain a system’s behavior over a certain time period. − − 在系统动力学方法论中，一个问题或一个系统(例如，生态系统、政治系统或机械系统)可以表示为一个环路图。环路图是一个系统的简单映射，包含了系统的所有组成部分及其相互作用。通过捕捉相互作用和随之而来的反馈回路(见下图) ，环路图揭示了一个系统的结构。通过了解一个系统的结构，就有可能确定一个系统在一定时间段内的行为。 − − − − − − The causal loop diagram of the new product introduction may look as follows: − − The causal loop diagram of the new product introduction may look as follows: + + − + − [[Image:Adoption CLD.svg|centre|Causal loop diagram of ''New product adoption'' model|frame]] − − frame − − 框架 − − − − − − There are two feedback loops in this diagram. The positive reinforcement (labeled R) loop on the right indicates that the more people have already adopted the new product, the stronger the word-of-mouth impact. There will be more references to the product, more demonstrations, and more reviews. This positive feedback should generate sales that continue to grow. − − There are two feedback loops in this diagram. The positive reinforcement (labeled R) loop on the right indicates that the more people have already adopted the new product, the stronger the word-of-mouth impact. There will be more references to the product, more demonstrations, and more reviews. This positive feedback should generate sales that continue to grow. − − 在这个图表中有两个反馈循环。右侧的正强化(标记为 r)循环表明，越多的人已经接受了新产品，口碑的影响就越强。将会有更多的产品参考，更多的演示和更多的评论。这种积极的反馈应该会产生持续增长的销售额。 − − − − − − The second feedback loop on the left is negative reinforcement (or "balancing" and hence labeled B). Clearly, growth cannot continue forever, because as more and more people adopt, there remain fewer and fewer potential adopters. − − The second feedback loop on the left is negative reinforcement (or "balancing" and hence labeled B). Clearly, growth cannot continue forever, because as more and more people adopt, there remain fewer and fewer potential adopters. − − − − − − − − Both feedback loops act simultaneously, but at different times they may have different strengths. Thus one might expect growing sales in the initial years, and then declining sales in the later years. However, in general a causal loop diagram does not specify the structure of a system sufficiently to permit determination of its behavior from the visual representation alone.<ref>Richardson, G. P. (1986), Problems with causal-loop diagrams. Syst. Dyn. Rev., 2: 158–170. doi:10.1002/sdr.4260020207</ref> − − Both feedback loops act simultaneously, but at different times they may have different strengths. Thus one might expect growing sales in the initial years, and then declining sales in the later years. However, in general a causal loop diagram does not specify the structure of a system sufficiently to permit determination of its behavior from the visual representation alone. − − 两种反馈循环同时发挥作用，但在不同的时间，它们可能有不同的优势。因此，人们可能会认为，最初几年的销售额会增长，随后几年销售额会下降。然而，一般来说，环路图并没有充分指定系统的结构，以允许仅仅通过视觉表现来确定其行为。 − − +
→因果循环图 Causal loop diagrams
===因果循环图 Causal loop diagrams===
===因果循环图 Causal loop diagrams===
在系统动力学方法论中，一个问题或一个系统(例如，生态系统、政治系统或机械系统)可以表示为一个环路图。环路图是一个系统的简单映射，包含了系统的所有组成部分及其相互作用。通过捕捉相互作用和随之而来的反馈回路(见下图) ，环路图揭示了一个系统的结构。通过了解一个系统的结构，就有可能确定一个系统在一定时间段内的行为。<ref>Meadows, Donella. (2008). Thinking in Systems: A Primer. Earthscan</ref>
新产品介绍的环路图如下:
新产品介绍的环路图如下:
[[Image:Adoption CLD.svg|centre| ''新产品采用''模型的因果循环图|frame]]
在这个图表中有两个反馈循环。右侧的正强化(标记为 R)循环表明，越多的人已经接受了新产品，口碑的影响就越强。将会有更多的产品参考，更多的演示和更多的评论。这种积极的反馈应该会产生持续增长的销售额。
左边的第二个反馈回路是负强化(或“平衡” ，因此标记为 B)。显然，增长不可能永远持续下去，因为随着越来越多的人采用，潜在的采用者越来越少。
左边的第二个反馈回路是负强化(或“平衡” ，因此标记为 b)。显然，增长不可能永远持续下去，因为随着越来越多的人采用，潜在的采用者越来越少。
两种反馈循环同时发挥作用，但在不同的时间，它们可能有不同的优势。因此，人们可能会认为，最初几年的销售额会增长，随后几年销售额会下降。然而，一般来说，环路图并没有充分指定系统的结构，以允许仅仅通过视觉表现来确定其行为。<ref>Richardson, G. P. (1986), Problems with causal-loop diagrams. Syst. Dyn. Rev., 2: 158–170. doi:10.1002/sdr.4260020207</ref>
===存量-流量图 Stock and flow diagrams===
===存量-流量图 Stock and flow diagrams===