How to invite the lonely employees to participate in collective work , and what means to use to get these workers outside their isolated world?

There are two approaches. Humanitarian and vocational. The first simply can be adopted through building good personal relation with introvert workers that makes them disclose their personal concerns leading them to sit away from others. The technical approach may be adopted through a wellset communication procedure. The good observation of the behaviour, performance, interaction, satisfaction, hardworking, career ambition, response to failure/ successs of the workers help to define the reasons behind isolation and uproot them