Gait Speed Measurement for Elderly Patients with Risk of Frailty. - Xavier Ferré; Elena Villalba Mora; Maria-Angeles Caballero-Mora; Alberto Sanchez; Williams Aguilera; Nuria Garcia-Grossocordon; Laura Nuñez-Jimenez; Leocadio Rodríguez-Mañas; Qin Liu 004; Francisco del Pozo-Guerrero (Mob. Inf. Syst., 2017)