ask item i ordered [
foreach [1 2] [gap -> create-sosyal-bag-with item ((i + gap) mod hane-sayisi) ordered]
]
]
; Ring with degree four, then random edge rewiring without self/duplicate links.
ask sosyal-baglar [
if random-float 1 < 0.05 [
let source end1
let target one-of haneler with [self != source and not link-neighbor? source]
if target != nobody [ask source [create-sosyal-bag-with target] die]
]
]
ask sosyal-baglar [set color [231 235 232] set thickness 0.01]
ask bankalar [
set mevduat-toplami sum [mevduat] of haneler with [bankam = myself]
set rezerv mevduat-toplami * rezerv-orani
set kredi mevduat-toplami - rezerv
set stres? false
]
set baslangic-servet sum [mevduat] of haneler
set baslangic-rezerv sum [rezerv] of bankalar
set karsilanamayan-talep 0 set toplam-transfer 0
reset-ticks
kontrol
end
to go
if ticks >= 120 [stop]
set karsilanamayan-talep 0
ask bankalar [set nakit-islem-kalan nakit-kapasitesi]
; Decisions use only the previous tick's bank stress and neighbour transfers.
ask haneler [
set yeni-gecis? false
let neighbor-signal 0
if any? link-neighbors [set neighbor-signal count link-neighbors with [gecen-gecis?] / count link-neighbors]
let bank-signal ifelse-value [stres?] of bankam [0.25] [0]
let news ifelse-value (ticks >= 10) [kriz-siddeti] [0]
set egilim news + sosyal-etki * neighbor-signal + bank-signal
let privacy-penalty gozetim-kaygisi * (1 - mahremiyet-duzeyi) * 0.2
let design-attraction (basvuru-guveni * ifelse-value itiraz-yolu-etkili? [0.08] [-0.08])
set design-attraction design-attraction + (odeme-ozerkligi * 0.04) + (mahremiyet-beklentisi * mahremiyet-duzeyi * 0.04)
if faiz-var-mi? [set design-attraction design-attraction + 0.04]
set hedef "nakit"
if cbdc-var-mi? and (limitsiz? or cbdc < elde-tutma-limiti) and (design-attraction - privacy-penalty >= -0.03) [set hedef "cbdc"]
if hedef = "cbdc" [set egilim egilim + design-attraction - privacy-penalty]
]
; Rotate deterministic service order so early agent ids do not monopolise cash capacity.
let ordered sort haneler
let offset ticks mod length ordered
foreach (sentence (sublist ordered offset (length ordered)) (sublist ordered 0 offset)) [a -> ask a [donustur]]
ask haneler [set gecen-gecis? yeni-gecis?]
ask bankalar [
set mevduat-toplami sum [mevduat] of haneler with [bankam = myself]
set stres? (rezerv < mevduat-toplami * 0.08)
set color ifelse-value stres? [[161 125 83]] [[11 106 100]]
]
kontrol
tick
end
to donustur
if egilim <= panik-esigi or mevduat <= 0 [stop]
let amount ifelse-value (hedef = "cbdc") [min list (mevduat * 0.08) 10] [min list (mevduat * 0.02) 3]
if hedef = "cbdc" and not limitsiz? [set amount min list amount (max list 0 (elde-tutma-limiti - cbdc))]
let available max list 0 [rezerv] of bankam
let actual min list amount available
if hedef = "nakit" and [nakit-islem-kalan] of bankam <= 0 [set actual 0]
set karsilanamayan-talep karsilanamayan-talep + (amount - actual)
if actual > 0 [
set mevduat mevduat - actual
ifelse hedef = "cbdc" [set cbdc cbdc + actual] [set nakit nakit + actual]
ask bankam [set rezerv rezerv - actual if [hedef] of myself = "nakit" [set nakit-islem-kalan nakit-islem-kalan - 1]]
set yeni-gecis? true
set color ifelse-value (cbdc > 0) [[11 106 100]] [[161 125 83]]
]
end
to kontrol
let wealth sum [mevduat + cbdc + nakit] of haneler
let base sum [rezerv] of bankalar + sum [cbdc + nakit] of haneler
if abs (wealth - baslangic-servet) > 0.000001 [error "Hane serveti korunmuyor"]
if abs (base - baslangic-rezerv) > 0.000001 [error "Merkez bankasi yukumlulukleri korunmuyor"]
if any? haneler with [mevduat < -0.000001 or cbdc < 0 or nakit < 0] [error "Negatif bakiye"]
ask bankalar [
if abs ((rezerv + kredi) - sum [mevduat] of haneler with [bankam = myself]) > 0.000001 [error "Banka bilancosu esit degil"]
]
end
to-report toplam-mevduat
report sum [mevduat] of haneler
end
to-report toplam-cbdc
report sum [cbdc] of haneler
end
to-report toplam-nakit
report sum [nakit] of haneler
end
to-report stresli-banka
report count bankalar with [stres?]
end
to-report limite-takilan-pay
if limitsiz? or not cbdc-var-mi? [report 0]
report count haneler with [cbdc >= elde-tutma-limiti - 0.000001] / count haneler
end
to-report yuksek-kaygi-cbdc-payi
let group haneler with [gozetim-kaygisi >= 0.5]
if not any? group [report 0]
report mean [cbdc / (mevduat + cbdc + nakit)] of group
end
to-report dusuk-kaygi-cbdc-payi
let group haneler with [gozetim-kaygisi < 0.5]
if not any? group [report 0]
report mean [cbdc / (mevduat + cbdc + nakit)] of group
end
]]>toplam-mevduattoplam-cbdctoplam-nakitstresli-bankalimite-takilan-paykarsilanamayan-talepplot toplam-mevduatplot toplam-cbdcplot toplam-nakit## DIGITAL MONEY IN A CRISIS
A theoretical CBDC-SPAR scenario prototype, not a forecast for Türkiye.
## HOW TO USE
Choose a random seed, crisis intensity and CBDC holding limit. Press Setup, then Run or One step. Cash and CBDC withdrawals consume the same banks’ initial liquid reserves.
## MECHANISMS
Households have deposits, cash, CBDC and heterogeneous behavioural scores. Four banks initially hold a liquid reserve fraction of deposits. The model includes a rewired social ring, social influence, withdrawal thresholds, asymmetric cash/CBDC transaction opportunities and a CBDC appeal term. No central-bank liquidity support, asset sales or interbank funding is modelled.
## INTERPRETATION
The aggregate withdrawal ceiling follows mechanically from the initial reserves. Long-run convergence to that ceiling is not evidence that CBDC independently causes a bank run. Holding limits can change composition and timing. The cash comparison depends on transaction speed, capacity and simulation horizon.
## VALIDATION
Accounting identities are checked at every step. The accompanying mechanism audit compares equalised transfer conditions and removes the CBDC appeal term from withdrawal tendency. Outputs are synthetic. No participant responses are collected.
## LIMITATIONS
Parameters are illustrative, not estimated from Turkish data. Network and bank assignment share an index; bank-specific contagion cannot be identified independently. The unserved-demand counter adds repeated attempts and is not unique unmet wealth. A zero holding limit requires careful interpretation of the cap indicator.
## SOURCES AND REPRODUCIBILITY
NetLogo 7.0.4, Wilensky (1999). The model source, ODD description, licence and fixed-seed experiment outputs are provided on the simulation page. CBDC-SPAR: Surveillance, Privacy, Autonomy, Redress.
setupgotoplam-mevduattoplam-cbdctoplam-nakitstresli-bankalimite-takilan-paykarsilanamayan-talepyuksek-kaygi-cbdc-payidusuk-kaygi-cbdc-payisetupgotoplam-mevduattoplam-cbdctoplam-nakitstresli-bankalimite-takilan-paykarsilanamayan-talepyuksek-kaygi-cbdc-payidusuk-kaygi-cbdc-payisetupgotoplam-mevduattoplam-cbdctoplam-nakit