Section: Research Program

User/system interaction

As we pointed out before, there is a strong need to present relevant patterns to the user. This can be done by using more specific constraints, background knowledge and/or tailor-made optimization functions. Due to the difficulty of determining these elements beforehand, one of the most promising solutions is that the system and the user co-construct the definition of most relevant patterns, i.e., to have a human in the loop. This requires to have means to present intermediate results to the user, and to get user feedback in order to guide the search space exploration process in the right direction. This is an important research axis for Lacodam, which will be tackled in several complementary ways:

• Domain Specific Languages: one way to interact with the user is to propose a Domain Specific Language (DSL) tailored to the domain at hand and to the analysis tasks to perform. The challenge is to propose a DSL allowing the users to easily express the required processing workflows, to deploy those workflows for mining large volumes of data and to offer as much automation as possible.

• What if / What for scenarios: we are also investigating the use of scenarios to query results from data mining processes, as well as other complex processes such as complex system simulations or model predictions. Such scenarios are answers to questions of the type “what if [situation]” or “what [should be done] for [expected outcome]”.

• User preferences: in exploratory analysis, users often do not have a precise enough idea of what they want, and are not able to formulate such queries. Lacodam is thus investigating simple ways for letting users express their interests and preferences, either during the mining process to guide the search space exploration, or after, to help in getting the most relevant results.

• Data visualization: most of the research directions presented in this document require users to examine patterns at some point. The output of most pattern mining algorithms is simply a (long) list of patterns. While this presentation can be sufficient in some applications, it is often not enough to provide a complete understanding, especially for non-experts in pattern mining. A transversal research topic that we want to develop in Lacodam is to propose data visualization techniques adequate to understanding output results. Numerous (failed) experiments have shown that data mining and data visualization are fields which require distinct skills, where researchers in one field usually do not make significant advances in the other field (this is detailed in [Keim 2010]). Thus, our strategy is to establish collaborations with prominent data visualization teams for this line of research, with a long term goal to recruit a specialist in data visualization if the opportunity arises.