The new method, increasing efficiency and reliability of change detection in three structures in the Internet data under indetermination of data structure (DTD, XML-Schema) is proposed in this paper. The Boolean linear programming problem was solved in two exact methods - modified Balazs with filter and modified DP method and A modified method for selecting a neural network architecture was proposed. There is also considered publish/subscribe system description enhanced with core module, which provides notifications of changes to subscribers only in case they occurred.