To manage and utilize huge amount of multimedia contents, various kinds of application software have been provided. However, they manage the contents based upon the property information of a file, such as file type, size, or date, therefore, it is hard to say that they allow us to easily access to the target contents with the only information of a file. In this context, in our study, we propose a method to firstly structurize the contents by using the `time' and `place' information of an event which tends to be naturally remembered in our everyday lives (In this paper, we call this information “Everyday life Ontology”), and then to operate the contents by natural language. In addition to the basic property information of a file, by using the constraints about time and location in order to manage the contents, we will be able to manage the contents considering the situation in which the contents were obtained. And, in order to operate application software by natural language, we have developed an ontology of the operation function of application software, which makes it possible to flexibly connect the user's natural language input with the commands of application software. Furthermore, we can access to the structured contents by using the time and place information used for its structure, this makes us possible to access other contents through the hierarchy and sequence of the structure from the contents currently being focused. We conducted an experiment to test the abilities of users to deal with multimedia contents and these constraints using our natural language interface, and then compared them to manual operations, evaluating them from the viewpoints of necessary time to achieve the given task and of the correctness of result. By this, the usefulness of the system and our proposed method was confirmed.
