Materi PDB Pertemuan 1

4/L6/2Ot4

What is System Dynamics?

...a methodology for studying andmanaging dynamic problems incomplex feedback systems.

Modeling Process

System Dynamics Modeling Process1. Detine the Problem Dynami(ally

th. tih..di6 gaphs ro no.. rh. 9.oU di. b$oiid ow t6.2. Develop a oynamic Hypothesis

u. diagtundko t@ls to.hnlb. th. tyttfr thdt E .t@tinq b.ptubhnotk b.hovid.

6. Formulate & SimulateI u* tunvdt to tuNbE th. didsni nb o.onput thad.hhokd.

< n utod rh. pnbhmtk b.hdw ot th. @t wtd tytuh.I

14. Test the ModelI condu.t dloonEtn on t wli.dtion E t olth.6od.l.--.

5. Design & Test Policiest'cl condqtdEtih@Ewith th. ^o.hl b.lifr@tan lNtudE poli.v

oprioB lor dctueinrth. @l*o.ld probhn.

SD Modeling: an Iterative ProcessD.lin. rh. Pobl.m DvnamhalV

tDev.lop ovn.nic Hypolheik

tFormulate & simulat rh. Mod.l

(,._.1"*.(,,.""[,,,",".,

lllustrating theModeling Process

+ D.tin. rh. P6brn or".n,allvod.lop t!En. HvDdhBh

romd.E & sinuh. ih. Mod.lT6r rh. Mod.lDesian P.li4!

Define a Problem DynamicallyGet iome data.nd daw a time serisgraph ofthe problem.ticbehavior That is, dlaw the E eEfte behovio. pottn loften.atted$. rclercn@ nod.l.

lnterpret the Sraph in mrd' That is, d.scibe th rerrPr..

4lL6l2OL4


/ D.nn.th. pEbkD oyn:mkrlly P *,+ D.Er., Dyi.mi.Hworh6it ll

"r.,-.Famul.E & timul.i. rh. Mod.lT.nrh. M.d.lD.cln roli.r6

Formulate and SimulateFormulate:

. write equationsthat reflect fundional relationshipsbtween variabls in the model.

. Enter those equationsin computersimulation softwarele.g., vensim,Stello/ilhinla Powe6iml.

Simulate:. t se the simulation softlvare to run the model. Compare modelt behaviorwith the referenc mode

Develop a "Dynamic" Hypothesis. Drawand labelthe key stock(slrelated to the rrernce mode.. Draw and labeltheflows ofthe key stockGl.

. Describe how the flow(sl could cause chantes in the stock(s).

. Hypothesiu e what causes the flows to chant,

. Hypothesize howthe stock & flow structure could produce the

. Translate the stock-and-flow structure into a causal loopdiagram to explain the dynamic hypothesis.

Structure and Behavior

Bahavior

-

etdc

Dynamic Hypothesis

*F,==;.,./.ktBehavior /" d'

/*./e{

Dynamlc Hypolh!3b: rcf.ronc. mod. b.t Yiorg.ncr.t d by n.r .t!.ct o( R .tructuru & G .lructun


r' Deli..rh. r6bkm DF. iallY/ D.v.lop orn.hi. Hworh..k

+ rdndrE & sinur.r. rh. Mod.rT.n $c raod.lD.sia. Pou.rr

P "*'H n"*.ol-lo

4lL6l2oL4

Replicate the Reference Mode

DE fiEt tutk in nod.litg i5lo E

4lL6l2OL4


/ Min.rh. P6br.m Dvn.miorry P "**

r' Dv.,op Dl,n.6i. Hypo,h6i! -

ll nr"*'*r' Fdmuh.& simurrr. rh. Mod.r

.-l rry$Brrh.M.d.rd.t ik l.ter+

D.risi,.rd.r '- Peo",

Validation is a Continuous Process

0,,,,(ff)6,r*"' ro buiu iunifi.bl.oifld.E an rh. nod.l

la- tn th' mod'l

What is "Poliqy'' and "Poliry Design"?trr. ,@r!t prebhru lh r..db..t ry*.m. by mn.,ht .to.L.,wb n.n.r. 3takr bv Eiul.tim n s i. oder lo ..hi.v. d.siEd 3tekr,

A ror., 13 . ..t of daCh.ntintrfi. b.h.viorEquiE3.i.nainirh. ir.uctuE,&rl9r,rrroli.yn.. ch.nrnld..itbnrul..rh.tpluLt no*t

uu.ll, by @.llnt nd f..db.d loo, ttn cloro.

Search for Leverage Points

rr r!!r ;

cd(q d.iry 6 .cl r.L a**a;!.j:gbyqo ininc Inlbci.i


r' Min. th. PDbkD Crn: idllyr'D.Elo!otn.h-HYpolhdr

r' romul.r. & sihul.rc rlE Mod.lr6t rh. irod.r d.r.ilt l.te.D.ria. PolidB d.EiB l.r.r

PH

-Lr)i^P\\y

Model Tbstjng: What dos Modd Validw ltl.ean?

e9!riC!!$E!-cara!sr:Uriqu.ornduniqu.?

Pa3i.nr or.d pr4n.nrl

oo

lgsrgEiCs$E!:L.$ mntn dr or nm dlidml?

L.$ rclul or noc ur.ful?6.ld .En& or rSoa mng.?

-E=!Er_-lhlklotinqd hod.l @n. orcviding ddcn. to juttty confu4.e in. ho.Ll.

. F,Rt, th. mod.l.r 64r d.v.lop|u$ i.bL.o.fid.nc..

. Th.n th. cli.nt fr6t dd.lop jdtitilbl. 6nfid.n...

4

Testinga Model(1) Conff rm unit consinen+(2llnltialize in equllibrium & eveluate a shock test.(3)Compare model behavior with refrnc mode.(4) Define and condud extreme condition tests,(5) Conduct and evaluate strudure/behaviortests.(5) Conduct parameter sensitivity tests.

4/L6/2Ot4

Intemal Consistencla Units

Why confirm unit consistency:t M.dd, *nh .qu.iio.s haini hMrtsEm un[s rE niil.rdiia

.id6u.lv*nhhs.t wh.n inMrind unib.E di*NEd 6t drrd, rh. E Ur.rioi

o,bdhrh. od.l ,nd mod.ln.ro drm{.d.

When to confirm unit consistencv:r

.! ,{ tomuln..n .cu.noi{d ir r3h rdn $. tun. tdr...rio: oo e.,,r!kt md Mh..d.$tW.

How to document unit consi5tency:. shw.ll unns on iah!!ld. dl .q!.tion .id d.monfin. $.t

rh.y Eduo ro rh. d..iEd unnr on rh. bn.id. ot thc .qu.tion.. rllu*Erid: bidhe

= poruLriff ! ldionJl6srh Et.p.MVF

- ,.mE' (p.Mtr.. !.EdllpsnvF,' p.Mc ' lrJrv!.4 = p.MB/ve

Extreme Condition Test. T.n lo. inpo$ibk E.l.Nld

n...ii[ inv.nldi..,.l. l. r.{t ,lotioll.6 i, unlik lr)Gultror Etin3srdk o. p.nn.r.trro

dEm.Elu6l.&,rml Fa a.mph, rhm rhould b. n..rcBrn6lh@ .E no polie ..d .o t.k an.i th4 .E no JudSls.

. PulD6.: ro idcnriry..d ,ir in@6 or i..d.qu.r..qurrid!.

1. h.3in. : lreilic.nm. .ondnion.2. Pddid rlE h.haior in rh.r @ndition.,. c6dudrh. r.n ro &. wh.r h.F9.nia.c6p.Erh. b!h.vio.* h Frrp..didi6i.s Fu.nyfl.sd..l.d byrh. i6r.

Cutting a Feedback toop

To ".ul'. t.db*l l@p h..n5 to elimin.te iB etu in th. n del.

typi..l wrys ol doiE rhis:! ll th.E i. . p.Bh.l., i. lh. loop th.l en !o io ED in Eal lib, $t it.

v.lu. toaF inrh. n.d.l,

.lfrh.E i!.n.djusr6.nrim. in rh.loop thatcould b. "v.ry lollB" in6.llif., s.t ite v.lu. ro . v.ry lair. numb.r(e.!.,1e+12).

t llrh.G is. i.hle tun.ti.n in th.looo iet.llotit3v.lu8roth.'no.fircl" valu. {i..., 1.0).

Equilibrium Shock Test. E.t blth.n inili.l.quilibnuh

. lmgin. . rp.dic $el l.1 .rd ptsdicl b.lEvior

. shet lh. .FLm io $. end h.Ppont

. C.mp3B ,E b.tqvid rilh your pddi.lion.

. Fix aiy nM 6v..Ld by lh. l.1

Strucure-Behavior Tests

. Cdrprc th. b.h idof . mod.l wlth & without th. i...tb.ck bop,

- ro ld.ntlfy wh.i p..t .f th. structuE is E3poNibl. ior errrin

ob6.r.d in lh. ntodel.-

to rBt th. dyn.di. lrypoth.rit-tolacih.t p.li.v dBian

Pe..,uE 6. F..db..k L@pAntlwt:1, Run rh. mod.l with th. L.d b.ck loop op.6tina, .o th.l you g.t.

"b.n.htu*a{om.lhins for @mp.risn.2. "cut th. looy' th.t you w.ntio.ElvE.3. Ru. th. nod.l !!!9!! th. b.db.ck k op, .nd s.. h th. b.hdior i.

4lt6l2OL4

Sensitivitv Testsld.nri,y pa.m.l.u oi,..dD.ck l@p.

F.r..cnt nmLrth.t you E lor.tt. slmol.L lith .ltF.tiw th. padmd.r vd6.. Cmp.B nrodal Daharior ll&lling lrm .ll.mtiE p.nmels vc4..

- r. an- ot Nn*, dlLdt Hdfrudr?

- Da.tuidllld Ehe chry?

& d.n ior polEy pe.m.td.-i... p.rm.loB lhe .li.nl highl b. .bl. lo co.lEl

B. d.n ro.'p.r.h.l.rJ in.l @uH b. .nd,oo.ni4d.

Policy Design

G.h.6llv,'policv" i3rh.lindividu.ls.nd.q.niarions "do" wtEnwith pEbl.ru th.v aE tryina t n.n.i.,

sFt m dyn.mi6 trEdek n.,aac p@blen5 in L.db..l ryri.n. byflas in ord.r to.chi.v. d6lEd 3tck..

Th.Ebc, in 5D nod.h, . ,.liry i! . *t ot d..klon tul.r u..d forb.tw..n d6iEd .nd .ctdl v.lu.r ol . .tck.

ln sDmd.lr, poli.i$ iE @nt imd in anlorErion L.db.ct l@p3 b!rw..n

O.tltnlry . ,olky EquiEs rrEnilh.niiA "B@d' loor5 ..d/or m.lc.i.g"b.d" ro.pi by .h.ng, !h. ltructuc or . mod.l,

6

Materi PDB Pertemuan 1

Documents

Transcript of Materi PDB Pertemuan 1