The INVENTORY sector

The variables

Vensim name Name Used variables Used parameters Variables using it Initial value Equation
Change in DDI 1/y CDDI DELDI ROCDDI DELDI \(\mathtt{CDDI}\left(t\right)=\mathtt{DELDI}\left(t\right)\cdot\mathtt{ROCDDI}\left(t\right)\)
Change in Price Index 1/y CPI IR PRIN PRIN \(\mathtt{CPI}\left(t\right)=\mathtt{IR}\left(t\right)\cdot\mathtt{PRIN}\left(t\right)\)
DELiveries Gu/y DEL DELDI PNIS EPP PPU DDI1980 INV RS SA \(\mathtt{DEL}\left(t\right)=\frac{\mathtt{DDI1980}\cdot\mathtt{ifelse}\left(\left(t>2000\right),\mathtt{PNIS}\left(t\right),1\right)\cdot\mathtt{EPP}\left(t\right)}{\mathtt{PPU}\cdot\mathtt{DELDI}\left(t\right)}\)
DELivery Delay - Index (1) DELDI CDDI CDDI DEL 1.0 \(\frac{\mathrm{d}\mathtt{DELDI}\left(t\right)}{\mathrm{d}t}=\mathtt{CDDI}\left(t\right)\)
Desired Shifts Worked - Index (1) DSWI PRI DRI INVEOSWI SSWI \(\mathtt{DSWI}\left(t\right)=1+\mathtt{INVEOSWI}\cdot\left(-1+\frac{\mathtt{PRI}\left(t\right)}{\mathtt{DRI}}\right)\)
Effective Purchasing Power Gdollar/y EPP TPP EPP DAT EPP DEL 28087.0 \(\frac{\mathrm{d}\mathtt{EPP}\left(t\right)}{\mathrm{d}t}=\frac{-\mathtt{EPP}\left(t\right)+\mathtt{TPP}\left(t\right)}{\mathtt{DAT}}\)
GDP Gdollar/y GDP OUTP PPU CO2GDP TCENSGDP CESGDP ECETSGDP COFO ECFTSGDP CIPIS CIPUS ISGDP GDPP ECTAGDP GSSGDP SC \(\mathtt{GDP}\left(t\right)=\mathtt{PPU}\cdot\mathtt{OUTP}\left(t\right)\)
Inventory Coverage y IC INV RS PRI \(\mathtt{IC}\left(t\right)=\frac{\mathtt{INV}\left(t\right)}{\mathtt{RS}\left(t\right)}\)
INVentory Gu INV OUTP DEL IC 11234.8 \(\frac{\mathrm{d}\mathtt{INV}\left(t\right)}{\mathrm{d}t}=-\mathtt{DEL}\left(t\right)+\mathtt{OUTP}\left(t\right)\)
Inflation Rate 1/y IR PRI MRIWI INVEOIN PI CPI WRER \(\mathtt{IR}\left(t\right)=\mathtt{INVEOIN}\cdot\left(-1+\frac{\mathtt{PRI}\left(t\right)}{\mathtt{MRIWI}}\right)\)
National Income Gdollar/y NI SA BCISNI CSGDP EGTF2022 GDB GFSNI GGIS GND GNISNI GSGDP IC2022 ITO ITW MGD OI SSGDP WI \(\mathtt{NI}\left(t\right)=\mathtt{SA}\left(t\right)\)
OUTPut Gu/y OUTP ORO SSWI SWI1980 INV GDP LAPR \(\mathtt{OUTP}\left(t\right)=\frac{\mathtt{ORO}\left(t\right)\cdot\mathtt{SSWI}\left(t\right)}{\mathtt{SWI1980}}\)
Pink Noise In Sales (1) PNIS DEL \(\mathtt{PNIS}\left(t\right)=1\)
Perceived Relative Inventory (1) PRI PRI IC ICPT DIC PRI DSWI IR ROCDDI 1.0 \(\frac{\mathrm{d}\mathtt{PRI}\left(t\right)}{\mathrm{d}t}=\frac{\frac{\mathtt{IC}\left(t\right)}{\mathtt{DIC}}-\mathtt{PRI}\left(t\right)}{\mathtt{ICPT}}\)
PRice INdex (1980=1) PRIN CPI CPI 1.0 \(\frac{\mathrm{d}\mathtt{PRIN}\left(t\right)}{\mathrm{d}t}=\mathtt{CPI}\left(t\right)\)
ROC in DDI 1/y ROCDDI PRI INVEODDI SRI CDDI \(\mathtt{ROCDDI}\left(t\right)=\mathtt{INVEODDI}\cdot\left(-1+\frac{\mathtt{PRI}\left(t\right)}{\mathtt{SRI}}\right)\)
Recent Sales Gu/y RS RS DEL SAT RS IC 28087.0 \(\frac{\mathrm{d}\mathtt{RS}\left(t\right)}{\mathrm{d}t}=\frac{-\mathtt{RS}\left(t\right)+\mathtt{DEL}\left(t\right)}{\mathtt{SAT}}\)
SAles Gdollar/y SA DEL PPU NI \(\mathtt{SA}\left(t\right)=\mathtt{PPU}\cdot\mathtt{DEL}\left(t\right)\)
ShiftS Worked - Index (1) SSWI DSWI SSWI TAS SSWI OUTP 1.0 \(\frac{\mathrm{d}\mathtt{SSWI}\left(t\right)}{\mathrm{d}t}=\frac{-\mathtt{SSWI}\left(t\right)+\mathtt{DSWI}\left(t\right)}{\mathtt{TAS}}\)

The parameters

Vensim name Name Is used by Value
Demand Adjustment Time y DAT EPP 1.2
DDI in 1980 y DDI1980 DEL 1.0
Desired Inventory Coverage y DIC PRI 0.4
Desired Relative Inventory DRI DSWI 1.0
Inventory Coverage Perception Time y ICPT PRI 0.25
sINVeoDDI < 0: INVentory Effect On Delivery Delay Index INVEODDI ROCDDI -0.6
sINVeoIN < 0: INVentory Effect On INflation INVEOIN IR -0.26
sINVeoSWI < 0: INVentory Effect On Shifts Worked Index INVEOSWI DSWI -0.6
Minimum Relative Inventory Without Inflation MRIWI IR 1.07
Price Per Unit /u PPU DEL GDP SA 1.0
Sales Averaging Time y SAT RS 1.0
Sufficient Relative Inventory SRI ROCDDI 1.0
SWI in 1980 SWI1980 OUTP 1.0
Time to Adjust Shifts y TAS SSWI 0.24