$1.$ Resource Over Allocation occurs where an asset is used to exceed its working limit beyond its normal working hours, which in some cases results in additional use of time and excess costs on the asset. $($Leus $\backslash$& Herroelen, $2004).$

$($a$)$Resource Levelling is one of the techniques of Resource Over Allocation applied in project control. Discuss reasons of Resource Levelling in managing the assets.

$($b$)$Explain with appropriate examples the influential factors in resource levelling for multi$-$projects.