8. A method for extending a default model for user context reasoning, the method comprising: generating first relationship information about a relationship between a concept included in the default model and a concept included in a linked model by matching the concept of the default model with the concept of the linked model based on concept relationship information, the concept relationship information comprising at least one of information about identical concepts, information about similar concepts, and information about upper and lower concepts; generating second relationship information about a relationship between a concept included in the linked model and a concept included in linked data by matching the concept of the linked model with the concept of the linked data; combining the default model and the linked model based on the first relationship information; and combining the linked model and the linked data based on the second relationship information.
8. A method for extending a default model for user context reasoning, the method comprising: generating first relationship information about a relationship between a concept included in the default model and a concept included in a linked model by matching the concept of the default model with the concept of the linked model based on concept relationship information, the concept relationship information comprising at least one of information about identical concepts, information about similar concepts, and information about upper and lower concepts; generating second relationship information about a relationship between a concept included in the linked model and a concept included in linked data by matching the concept of the linked model with the concept of the linked data; combining the default model and the linked model based on the first relationship information; and combining the linked model and the linked data based on the second relationship information. 12. The method of claim 8 , wherein the generating of the second relationship information comprises extracting identical concepts from concepts included in the linked model and the linked data using at least one of string matching, structure matching, upper-level ontology-based semantic matching, and WordNet-based matching, and generating the second relationship information that indicates that the extracted concepts are identical.