1. Technical Field
The present invention relates to profile management systems and, in particular, to a method and apparatus for updating user profiles based upon personalized reasoning about user activity.
2. Related Art
It is known to provide online products and services customised in their operation to particular users according to information contained in respective user profiles. It is also known to update user profiles automatically over time to keep track of changes observed in a user's interests, and for application programs implementing products and services to adapt to such changes.
In a co-pending international patent application number PCT/GB02/01421 by the present Applicants, published under reference WO 02/080056, a profile management system is described in which a user profile is generated, the profile comprising a weighted selection of keywords representing the user's interests and attributes of those interests. Interest attributes may include expertise level of the user in respect of a particular interest, an importance rating for the interest, a privacy marking in respect of the interest and a duration factor relating to the duration of the interest. These attributes may be set as appropriate by a user. In addition, weights may be assigned to certain of those attributes, not only to indicate the relevance/importance of the attribute to the interest, but also to suit the individual user, providing a high degree of “fine-tuning” in profiles and hence to products and services that access those profiles. A method is also described for updating a user profile generated by that system, in particular for using a fuzzy inference engine and pre-designed fuzzy sets and fuzzy rules to semi-automatically update weightings associated with keywords and attributes of interests stored within a user's profile, on the basis of the user's information retrieval activity.
A paper entitled “Designing Agents for a Virtual Marketplace” by K. Kamyab, F. Guerin, P. Goulev and E. Mambani, Imperial College of Science, Technology and Medicine, London, describes a multi-agent architecture for a virtual sales assistant, including the idea of using pre-designed fuzzy sets and fuzzy rules to model a user's product preferences (e.g. to model linguistic terms such as “like”, “dislike”) and product descriptions (e.g. qualitative concepts such as “cheap”, “expensive”). Differing user perceptions of the meaning of these terms are modeled by varying the distribution of membership functions within each fuzzy set. An agent captures feedback from a user and uses a fuzzy inference engine to update the model of user preferences in respect of particular products.
Known arrangements for generating updates to a user profile using fuzzy inference may be represented in overview as shown in FIG. 1. Referring to FIG. 1, a fuzzy inference engine 100 is provided to infer updates to a user profile 105 according to predefined fuzzy rules 110 and fuzzy sets 115 on the basis of input event statistics 120, e.g. results from the monitoring of documents accessed by a user and feedback by the user as to the relevance of accessed documents to the user's interests. For example, the fuzzy inference engine 100 may infer from the recent access by a user of documents relating to a particular category of interest, that this interest should be represented in the contents of the user's profile 105, so generating an update to add certain keywords to the profile 105, or to increase the value of a weighting associated with this interest if already represented in the profile 105. Fuzzy inference processes suitable for use in this arrangement are described for example in “Fuzzy Sets” by L. Zadeh, Journal of Information and Control, Volume 8, 1965, pp338-353, and “Fuzzy Logic Controllers”, Parts 1 and 2, by C. Lee, IEEE Transactions on Systems, Management and Cybernetics, Volume 20, 1990, pp404-435.
It is known that user profiles (generated manually or by means of some automatic user modelling process) are essential to providing personalized products, information and services, for example in the context of the Internet or over corporate intranets. It is also known that these user profiles, describing user interests/needs and preferences, may change over time and that automatic systems capable of detecting these changes and making corresponding updates to profile data are highly desirable. However, whereas prior art arrangements are known to employ, for example, fuzzy sets to represent certain user preferences and to employ pre-designed fuzzy rules to infer updates to a user's profile, they offer little in the way of user control and personalisation of the profile update process itself.