系统动力学(名词解释)

名词解释：

System Dynamics：A powerful methodology for framing, understanding, and discussing complex policy issues and problems,is a methodology for studying and managing complex feedback systems, such as one finds in business and other social systems.

Mental models:are the images (attitudes and assumptions) we carry in our minds about ourselves, other people, institutions, and every aspect of the world which guide our interpretations and behavior.

System:The behavior of a system depends not only on the behavior of the components of a system but also on how these components interact.

System dynamics:is the application of systems theory to the behavior of complex systems. complex systems:are systems in which there are multiple interactions between many different components (or agents).

dynamic hypothesis:Once the problem has been identified and characterized over an appropriate time, modeler must develop a theory called “dynamic hypothesis”that accounts for the problematic behavior.

Chaos:When the present determines the future, but the approximate present does not approximately determine the future

limit cycles:If an oscillatory system with a locally unstable equilibrium is given a slight nudge off its equilibrium point, its swings grow larger and larger until they are constrained by various nonlinearities. Such oscillations are known as limit cycles.

dynamic complexity:The complexity generated by the interactive-feedback causality

directed graph:It is a graph, or set of nodes connected by edges, where the edges have a direction associated with them.

Cause and effect :is a simple idea in which actions and decisions have consequences, Feedback: is the process in which an action taken by a person or thing will eventually affect that person or thing.

Feedback loop: is a closed sequence of causes and effects

简答：

1.The problem of system dynamics has the following four characteristics:

Complexity: On one hand many factors are included in the system; on the other hand these factors in the given system are connected with each other.

Dynamics: Dynamic characteristics reflect the developing and changing laws of nature.

Nonlinearity. Nonlinear characteristics are important relationships among many factors in system dynamics.

Time lag: It describes a situation where the system or a certain part of the system only change after a period of time under the input.

2.Steps of the modeling process

Step 1 Problem Articulation (Boundary Selection):Theme selection, Key variables, Time horizon, Dynamic problem definition (reference modes).

Step 2 Formulation of Dynamic Hypothesis:Initial hypothesis generation, Endogenous focus,