Developing an effective social presence system for older adults: The Connected Vitality Network. - Achilleas Achilleos; Christos Mettouris; George A. Papadopoulos; Katja Neureiter; Claudia Rappold; Christiane Moser; Manfred Tscheligi; Lóránt Vajda; Andras Toth; Peter Hanák; Omar Jimenez; Robbert Smit (ITI, 2013)