An ontological approach to lifelog representation for disclosure control

In services using lifelog collected continuously and over a long period of time, disclosure control is essential in order to deal with the privacy because this lifelog includes confidential information which users are unwilling to disclose freely. This paper proposes an ontology model for disclosure control needed to handle each user's lifelog. The user is able to easily set disclosure rules on his/her diverse data collected from various data sources. Features of the proposed model are as follows: (1) Values can be differentiated by their context, (2) Various time expressions can be handled and (3) Disclosure attribute is set on each lifelog item (fine-grained control). We show an example of implementation and the result of experiments using an implemented system.