系统动力学全英文版 期末考试汇总文档格式.docx

系统动力学全英文版 期末考试汇总文档格式.docx

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1）Systemsthinking2）Personalmastery3）Mentalmodels

4）Buildingsharedvision5）Teamlearning

2.ThedefinitionofMentalModels

Mentalmodelsaretheimages（attitudesandassumptions）wecarryinourmindsaboutourselves,otherpeople,institutions,andeveryaspectoftheworldwhichguideourinterpretationsandbehavior.

3.ButterflyEffect

Thebutterflyeffectisthesensitivedependenceoninitialconditionsinwhichasmallchangeatoneplaceinadeterministicnonlinearsystemcanresultinlargedifferencesinalaterstate.

Chapter2:

SystemsandSystemThinking

1.Modelingconcepts

Amodelisanabstractionofarealobjectorsystem.

2.Systemdefinition

Asystemisasetoftwoormoreelementsthatsatisfiesthefollowingthreeconditions:

✧Itfulfillsacertainfunction

✧Thebehaviorofeachelementhasaneffectonthebehaviorofthewhole

✧Thebehavioroftheelementsandtheireffectsonthewholeareinterdependent

Thebehaviorofasystemdependsnotonlyonthebehaviorofthecomponentsofasystembutalsoonhowthesecomponentsinteract.

3.Systemcomponents

1）Objects2）States3）Events4）Time5）Space6）Structure

4.“Complexsystems”aresystemsinwhichtherearemultipleinteractionsbetweenmanydifferentcomponents（oragents）.Acomplexsystemischaracterizedbymultipleagentswhoseinteractionsgiverisetostructuraleffectsthataren’tapparentintheagentsthemselves.

Chapter4:

StructureandBehaviorofDynamicSystems

4.1Fundamentalmodesofdynamicbehavior

Fundamentalmodesofdynamicbehavior

Themostfundamentalmodesofbehaviorareexponentialgrowth,goalseeking,andoscillation.Eachoftheseisgeneratedbyasimplefeedbackstructure:

-Exponentialgrowtharisesfrompositivefeedback

-Goalseekingarisesfromnegativefeedback

-Oscillationarisesfromnegativefeedbackwithtimedelaysintheloop.

Othercommonmodesofbehavior,includingS-shapedgrowth,S-shapedgrowthwithovershootandoscillation,andovershootandcollapse,arisefromnonlinearinteractionsofthefundamentalfeedbackstructures.

4.1.1ExponentialGrowth

Exponentialgrowtharisesfrompositive（self-reinforcing）feedback.Thelargerthequantity,thegreateritsnetincrease,furtheraugmentingthequantityandleadingtoever-fastergrowth.

Pureexponentialgrowthhastheremarkablepropertythatthedoublingtimeisconstant:

thestateofthesystemdoublesinafixedperiodoftime,nomatterhowlarge.

WhenaRateIsNotaRate

Indynamicmodeling,theterm"

rate"

generallyreferstotheabsoluterateofchangeinaquantity.Theterm"

birthrate"

herereferstothenumberofpeoplebornpertimeperiod.Often,however,theterm"

isusedasshorthandforthefractionalrateofchangeofavariable.Forexample,thebirthrateisofteninterpretedasthenumberofbirthsperyearperthousandpeople.Similarly,wecommonlyspeakoftheunemploymentrate.Theword"

inthesecasesactuallymeans"

ratio"

:

theunemploymentrateistheratioofthenumberofunemployedworkerstothelaborforce

✧Theunitsofmeasureforratesofflowareunits/timeperiod.

✧Theunitsofmeasureforfractionalratesofflowareunitsperunitpertimeperiod=1/timeperiods.

4.1.2GoalSeeking

Negativeloopsseekbalance,equilibrium,andstasis.Negativefeedbackloopsacttobringthestateofthesysteminlinewithagoalordesiredstate.

Whentherelationshipbetweenthesizeofthegapandthecorrectiveactionislinear,therateofadjustmentisexactlyproportionaltothesizeofthegapandtheresultinggoal-seekingbehaviorisexponentialdecay.Asthegapfalls,sotoodoestheadjustmentrate.

Everynegativeloopincludesaprocesstocomparethedesiredandactualconditionsandtakecorrectiveaction.

4.1.3Oscillation

Oscillationisthethirdfundamentalmodeofbehaviorobservedindynamicsystems.Likegoal-seekingbehavior,oscillationsarecausedbynegativefeedbackloops.

Inanoscillatorysystem,thestateofthesystemconstantlyovershootsitsgoalorequilibriumstate,reverses,thenundershoots,andsoon.

Theovershootingarisesfromthepresenceofsignificanttimedelaysinthenegativeloop.Thetimedelayscausecorrectiveactionstocontinueevenafterthestateofthesystemreachesitsgoal,forcingthesystemtoadjusttoomuch,andtriggeringanewcorrectionintheoppositedirection

Oscillationsareamongthemostcommonmodesofbehaviorindynamicsystems.

DampedoscillationsLimitcyclesChaos

Oscillationscanariseifthereisasignificantdelayinanypartofthenegativeloop.

Perceivingthestateofthesystemcausedbythemeasurementandreportingsystem

Initiatingcorrectiveactionsafterthediscrepancyisperceivedduetothetimerequiredtor