On Nonlinear Inverse Problems of Heat Transfer with Radiation Boundary Conditions: Application to Dehydration of Gypsum Plasterboards Exposed to Fire

Table 2

Method	Notation	Description
Constant step	cst𝜌	𝜌𝑘=𝜌
Decreasing step	dim𝜌	𝜌0=𝜌,  𝜌𝑘=𝜌𝑘−12 if 𝐽𝜂𝑘>𝐽𝜂𝑘−1 (not changed elsewhere)
Minimum step	min	𝜌𝑘1=min1,𝑔^(𝑘)∞
Optimal step	opt	𝜌𝑘 is an approximate solution of min𝜌≥0𝐽𝜂𝑘+𝜌𝑑^(𝑘)