RCA-Seq: an Original Approach for Enhancing the Analysis of Sequential Data Based on Hierarchies of Multilevel Closed Partially-Ordered Patterns

International audienceMethods for analysing sequential data generally produce a huge number of sequential patterns that have then to be evaluated and interpreted by domain experts. To diminish this number and thus the difficulty of the interpretation task, methods that directly extract a more compact representation of sequential patterns, namely closed partially-ordered patterns (CPO-patterns), were introduced. In spite of the fewer number of obtained CPO-patterns, their analysis is still a challenging task for experts since they are unorgan-ised and besides, do not provide a global view of the discovered regularities. To address these problems, we present and formalise an original approach within the framework of Relational Concept Analysis (RCA), referred to as RCA-Seq, that focuses on facilitating the interpretation task of experts. The hierarchical RCA result allows to directly obtain and organize the relationships between the extracted CPO-patterns. Moreover, a generalisation order on items is also revealed, and multilevel CPO-patterns are obtained. Therefore, a hierarchy of such CPO-patterns guides the interpretation task, helps experts in better understanding the extracted patterns, and minimises the chance of overlooking interesting CPO-patterns. RCA-Seq is compared with another approach that relies on pattern structures. In addition, we highlight the adaptability of RCA-Seq by integrating a user-defined tax-* onomy over the items, and by considering user-specified constraints on the order relations on itemsets

How Hierarchies of Concept Graphs Can Facilitate the Interpretation of RCA Lattices?

International audienceRelational Concept Analysis (RCA) has been introduced in order to allow concept analysis on multi-relational data. It significantly widens the field of application of Formal Concept Analysis (FCA), and it produces richer concept intents that are similar to concept definitions in Description Logics (DL). However, reading and interpreting RCA concept lattices is notoriously difficult. Nica et al have proposed to represent RCA intents by cpo-patterns in the special case of sequence structures. We propose an equivalent representation of a family of RCA concept lattices in the form of a hierarchy of concept graphs. Each concept belongs to one concept graph, and each concept graph exhibits the relationships between several concepts. A concept graph is generally transversal to several lattices, and therefore highlights the relationships between different types of objects. We show the benefits of our approach on several use cases from the RCA litterature