η

:

Demand coefficient

β

:

Demand constant, β ≥ 1

s

:

Selling price (in ₹/unit)

t_m

:

Time during which there is no deterioration

t₁

:

Time at which inventory level becomes zero

T

:

Duration of cycle

C_HC

:

Holding cost (in ₹/unit)

C_PC

:

Purchase cost (in ₹/unit)

C_DC

:

Deterioration cost (in ₹/unit)

C_OC

:

Ordering cost (in ₹/order)

C_SC

:

Shortage cost (in ₹/unit)

θ (t)

=

γλt^λ−1, Two-parameter Weibull distribution deterioration rate per unit per unit time, where γ represents scale parameter and λ represents shape parameter

I₁ (t)

:

Inventory level, at any time t, during [0, t_m]

I₂ (t)

:

Inventory level, at any time t, during [t_m, t₁]

I₃ (t)

:

Inventory level, at any time t, during [t₁, T]

C (t₁, T)

:

Total inventory cost (in ₹)

$\tilde{\eta }$

:

Fuzzy demand coefficient

$\tilde{\beta }$

:

Fuzzy demand constant

${\tilde{C}}_{HC}$

:

Fuzzy holding cost (in ₹/unit)

${\tilde{C}}_{DC}$

:

Fuzzy deterioration cost (in ₹/unit)

${\tilde{C}}_{OC}$

:

Fuzzy ordering cost (in ₹/order)

${\tilde{C}}_{PC}$

:

Fuzzy purchase cost (in ₹/unit)

${\tilde{C}}_{SC}$

:

Fuzzy shortage cost (in ₹/unit)