Table 1 Description of the individual adapted models and aggregation methods considered in the case study. \(C_1\) and \(C_2\) correspond to the computational costs of GAM and Kalman variances estimation, respectively. \(m_T\) is the number of targets in the transfer learning context, and \(n_i\) is the number of experts in the three aggregation methods. To give an order of magnitude, in our application, parameters \(n_i\) are inferior to 10 while \(m_T = 1344\).

From: Frugal day-ahead forecasting of multiple local electricity loads by aggregating adaptive models

Characteristics of adapted GAM

GAM + Kalman Static

GAM + Kalman Dynamic

AGG GAM TL

AGG GAM-Kalman TL

AGG Kalman TL

Transfer of GAM

No

No

Yes

Yes

No

Cost

\(C_1 \times m_T\)

\(C_1 \times m_T\)

\(C_1 \times n_1<< C_1 \times m_T\)

\(C_1 \times n_2<< C_1 \times m_T\)

\(C_1 \times m_T\)

Transfer of Kalman variances

No

Yes

Yes

Cost

\(C_2 \times m_T\)

\(C_2 \times n_2<< C_2 \times m_T\)

\(C_2 \times n_3<< C_2 \times m_T\)

Model type

\({\mathscr {M}}_{k,0,k}\)

\({\mathscr {M}}_{k,k,k}\)

\({\mathscr {M}}_{i,\emptyset ,k}\)

\({\mathscr {M}}_{i,i,k}\)

\({\mathscr {M}}_{k,j,k}\)

Total cost

\(C_1 \times m_T\)

\((C_1 + C_2) \times m_T\)

\(C_1 \times n_1\)

\((C_1 + C_2) \times n_2\)

\(C_1 \times m_T + C_2 \times n_3\)