系统动力学全英文版 期末考试汇总文档格式.docx

1、1） Systems thinking 2） Personal mastery 3） Mental models 4） Building shared vision 5） Team learning2. The definition of Mental ModelsMental 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 o

2、ur interpretations and behavior.3. Butterfly EffectThe butterfly effect is the sensitive dependence on initial conditions in which a small change at one place in a deterministic nonlinear system can result in large differences in a later state.Chapter2: Systems and System Thinking1. Modeling concept

3、sA model is an abstraction of a real object or system.2. System definitionA system is a set of two or more elements that satisfies the following three conditions: It fulfills a certain function The behavior of each element has an effect on the behavior of the whole The behavior of the elements and t

4、heir effects on the whole are interdependentThe behavior of a system depends not only on the behavior of the components of a system but also on how these components interact.3. System components1） Objects 2） States 3） Events 4） Time 5） Space 6）Structure4. “Complex systems” are systems in which there

5、 are multiple interactions between many different components （or agents）. A complex system is characterized by multiple agents whose interactions give rise to structural effects that arent apparent in the agents themselves.Chapter 4: Structure and Behavior of Dynamic Systems4.1 Fundamental modes of

6、dynamic behaviorFundamental modes of dynamic behaviorThe most fundamental modes of behavior are exponential growth, goal seeking, and oscillation. Each of these is generated by a simple feedback structure:- Exponential growth arises from positive feedback- Goal seeking arises from negative feedback-

7、 Oscillation arises from negative feedback with time delays in the loop. Other common modes of behavior, including S-shaped growth, S-shaped growth with overshoot and oscillation, and overshoot and collapse, arise from nonlinear interactions of the fundamental feedback structures. 4.1.1 Exponential

8、GrowthExponential growth arises from positive （self-reinforcing） feedback. The larger the quantity, the greater its net increase, further augmenting the quantity and leading to ever-faster growth.Pure exponential growth has the remarkable property that the doubling time is constant: the state of the

9、 system doubles in a fixed period of time, no matter how large.When a Rate Is Not a RateIn dynamic modeling, the term rate generally refers to the absolute rate of change in a quantity. The term birth rate here refers to the number of people born per time period. Often, however, the term is used as

10、shorthand for the fractional rate of change of a variable. For example, the birth rate is often interpreted as the number of births per year per thousand people. Similarly, we commonly speak of the unemployment rate. The word in these cases actually means ratio: the unemployment rate is the ratio of

11、 the number of unemployed workers to the labor force The units of measure for rates of flow are units/time period. The units of measure for fractional rates of flow are units per unit per time period = 1/time periods.4.1.2 Goal SeekingNegative loops seek balance, equilibrium, and stasis. Negative fe

12、edback loops act to bring the state of the system in line with a goal or desired state. When the relationship between the size of the gap and the corrective action is linear, the rate of adjustment is exactly proportional to the size of the gap and the resulting goal-seeking behavior is exponential

13、decay. As the gap falls, so too does the adjustment rate. Every negative loop includes a process to compare the desired and actual conditions and take corrective action. 4.1.3 OscillationOscillation is the third fundamental mode of behavior observed in dynamic systems. Like goal-seeking behavior, os

14、cillations are caused by negative feedback loops. In an oscillatory system, the state of the system constantly overshoots its goal or equilibrium state, reverses, then undershoots, and so on. The overshooting arises from the presence of significant time delays in the negative loop. The time delays c

15、ause corrective actions to continue even after the state of the system reaches its goal, forcing the system to adjust too much, and triggering a new correction in the opposite direction Oscillations are among the most common modes of behavior in dynamic systems. Damped oscillations Limit cycles Chaos Oscillations can arise if there is a significant delay in any part of the negative loop. Perceiving the state of the system caused by the measurement and reporting system Initiating corrective actions after the discrepancy is perceived due to the time required to r