I. Introduction
In recent years, much research on ambient assisted living (AAL) [1] has been conducted with the purpose of improving quality of life by supporting users' independent lives while monitoring their safety. For example, in the case of dementia patients, a system can even warn the users if they are skipping their usual activities, such as taking medicines [2]. To reduce the burden of nursing care, a demand for services that monitor living environments has been increasing. AAL systems can detect unusual situations using embedded and distributed sensors. However, monitoring environments is not enough if users want to deal with unusual events to avoid serious emergency situations. Notification of monitoring results is crucial to realize useful AAL support. This support should be less stressful, and it should be easy for users to understand messages, because the AAL systems are constantly used in everyday life. Nevertheless, methods of communicating monitoring status with the users in daily living environments have hardly been discussed.