*4.3. Knowledge Transfer*

It is clear that the aforementioned three conditions, e.g., solar irradiation, temperature, and PSC, can be considered as the main similarities between various optimization tasks. On the other hand, the similarity between two adjacent optimization tasks is usually very high, since these weather conditions cannot vary dramatically in a very short time. Hence, the optimal knowledge matrices of the adjacent past task is chosen for knowledge transfer to the new task (See Figure 3), while the similarity described in (11) can be designed as

$$r = 1 - \frac{\left| T\_{\rm c}^{\rm n} - T\_{\rm c}^{\rm P} \right|}{T\_{\rm ref}} - \prod\_{w=1}^{N\_{\rm s} \cdot N\_{\rm P}} \frac{\left| S\_{\rm w}^{\rm n} - S\_{\rm w}^{\rm P} \right|}{S\_{\rm ref}} \tag{13}$$

where *T*ncand *T*pcare the temperatures of the new task and the past task, respectively;
