Table 3.

Efficiency, utilization, and stress criteria included in the multi-objective function.

Criterion	Description
${\displaystyle \sum _{\mathit{i}\in \mathit{I}}}{\displaystyle \sum _{\mathit{j}\in \mathit{J}}}{\mathit{c}}_{\mathit{i}\mathit{j}}{\mathit{x}}_{\mathit{i}\mathit{j}}$	Efficiency of assignment of all robots/caregivers to all elderly
${\displaystyle \sum _{\mathit{i}\in \mathit{I}}}{\displaystyle \sum _{\mathit{j}\in \mathit{J}}}{\mathit{a}}_{\mathit{i}\mathit{j}}{\mathit{x}}_{\mathit{i}\mathit{j}}$	Level of all robots’ utilization, while serving all elderly
${\displaystyle \sum _{\mathit{i}\in \mathit{I}}}{\displaystyle \sum _{\mathit{j}\in \mathit{J}}}{\mathit{b}}_{\mathit{i}\mathit{j}}{\mathit{x}}_{\mathit{i}\mathit{j}}$	All caregivers’ stress level, while helping all elderly