Study on the user profile of personalized service in digital library

Structure and mechanism of user profile in digital library personalized service is presented. Key problems about the construction of user profile are introduced in details. These problems include the representation, creation and updating of user profile. The user profile is represented by a vector space model (VSM) based ontology. Simple domain ontology of digital library is built up first, and then the user's interests represented by VSM, in which the item of vector is ontology or concept about user's interests. User's interests are extracted by combining classification and clustering algorithms, taking the support vector machine (SVM) and unsupervised clustering (UC) as examples to show their implementation. Updating of user profile is implemented by using hybrid algorithm, containing time window and gradual forgetting.