Objective function k Thermal conductivity, W/m °C L Length, m M Number of nodes at spatial coordinate N Number of temporal measurements q ′′ (t) Surface heat flux, W/m 2 q m Metabolic heat generation, W/m 3 T (x, t) Temperature, °C �T (x, t) Sensitivity problem, °C t Temporal coordinate, s W (T ) Convective heat exchange with blood flow, W/m 3 x Spatial coordinate, m Y (t) Measured temperature, °C Greek symbols β Search step size γ Conjugate coefficient δ Dirac delta function ε Convergence criterion ζ Transformed time coordinate, s (x, t) Adjoint function µ Random variable ρ Density, kg/m 3 σ Standard deviation of the measurement errors τ Thermal relaxation time, s ω Perfusion rate of blood, m 3 /s/m 3 Subscript b Blood c Conduction heat transfer es Estimated value ex Exact value f Final value initial Initial value