Ambient Assisted Living [Guest editors´ introduction]

Ambient assisted living (AAL) can be defined as “the use of information and communication technologies (ICT) in a person´s daily living and working environment to enable them to stay active longer, remain socially connected and live independently into old age” (www.aal-europe.eu). Research in the AAL community covers a wide range of topics, but one of the largest is human activity recognition and behavior understanding, with the objectives of detecting and recognizing actions, activity, and situations within an environment. AAL systems go beyond observing to interact with users. A frequently employed form of human-machine interaction is via prompts-for example, prompting the user to perform the next step in a sequence of actions. Another type of interaction is haptic responses, which have been used in systems for visually impaired people. Two important elements of an appropriate response are an understanding of the user´s context and anticipatory capability. Context awareness underpins much of AAL research-human activities are generally context dependent. In the broader sense, context awareness uses sensor observations to abstract information about the current situation. Endowing a system with predictive capability lets it anticipate and thereby produce a timely and useful response.