Apparatus and method for dynamic meta-tagging of compound documents

Abstract

A method and apparatus to dynamically maintain META-tag information specifying categorization and/or degree of compound documents, which are collections or hierarchy of collections of objects (possibly web pages), for efficient retrieval of leaf or intermediate objects with specific characteristics without the need to search any content of the collection. The specific characteristic and the contents of the collection can change constantly both qualitatively and quantitatively (including the insertion, deletion and update of objects). While dynamically maintaining the META-tag information, there are no inclusion restrictions on these compound documents, i.e., any collection can contain itself either directly or recursively; and all objects within a META-tagged compound document are not required to participate. The PICS protocol may be used to specify this META-tag information with both categorization and degree; to reflect the obsolescence, currency or freshness of an objects; to validate a given object using a digital signature; and to enable charging for the META-tag service. Aggregation methods are provided to enable maximization, minimization, and averaging; to limit the propagation of META-tags; and to handle the time-out of META-tag and information validity.