As web sites are getting more complicated, the construction of web information extraction systems becomes more troublesome and time-consuming. A common theme is the difficulty in locating the segments of a page in which the target information is contained, which we call the informative blocks. This article reports on the Recognising Informative Page Blocks algorithm (RIPB), which is able to ide...

The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent the actions as a sequence of temporal isolated instances, denoted primitives. These primitives are ea...

Many data on the Web are XML documents. An XML document is an unranked labelled tree. A schema for XML documents (for instance a DTD) is the specification of their internal structure: a schema is a tree grammar, and validating a document w.r.t. a schema is done by a running of a tree automaton. Given a document, valid w.r.t. a DTD, and a sequence of updates (insertions, deletions and replacemen...

We propose a new method for computing the tree edit distance between two unordered trees by problem encoding. Our method transforms an instance of the computation into an instance of some IP problems and solves it by an efficient IP solver. The tree edit distance is defined as the minimum cost of a sequence of edit operations (either substitution, deletion, or insertion) to transform a tree int...

Many AI tasks require determining whether two knowledge representations encode the same knowledge. For example, rule-based classification requires matching rule antecedents with working memory; information retrieval requires matching queries with documents; and some knowledge-acquisition tasks require matching new information with already encoded knowledge to expand upon and debug both of them....

Graph theory has drawn a lot of attention in the field of Neuroscience during the last decade, mainly due to the abundance of tools that it provides to explore the interactions of elements in a complex network like the brain. The local and global organization of a brain network can shed light on mechanisms of complex cognitive functions, while disruptions within the network can be linked to neu...

An RNA molecule is structured on several layers. The primary and most obvious structure is its sequence of bases, i.e. a word over the alphabet {A, C, G, U}. The higher structure is a set of one-to-one base-pairings resulting in a two-dimensional folding of the one-dimensional sequence. One speaks of a secondary structure if these pairings do not cross and of a tertiary structure otherwise. Sin...

An ordered labeled tree is a tree where the left-to-right order among siblings is significant. Given two ordered labeled trees, the edit distance between them is the minimum cost edit operations that convert one tree to the other. In this thesis, we present an algorithm for the tree edit distance problem by using the optimal tree decomposition strategy. By combining the vertical compression of ...

We consider the setting of Reeb graphs of piecewise linear functions and study distances between them that are stable, meaning that functions which are similar in the supremum norm ought to have similar Reeb graphs. We define an edit distance for Reeb graphs and prove that it is stable and universal, meaning that it provides an upper bound to any other stable distance. In contrast, via a specif...