BLIZAAR - Hybrid Visualization of Dynamic Multilayer Graphs

An international collaborative research project funded jointly by the ANR (Project ANR-15-CE23-0002) and the FNR.

The project involves four partners:

BLIZAAR is an international collaborative project (PRCI) proposal which fits in the “Information and Communication Society” challenge. It involves French and Luxembourgish partners working in collaboration to craft novel ways of exploring and analyzing dynamic multilayer networks.

Our main application domain is digital cultural heritage with DEIS (Digital European Integration Studies). It concerns the collection, preservation, analysis and provision of open access to digitized cultural heritage objects, which may be any man-made object throughout history. In recent years, large amounts of digitized materials have for the first time become freely available to the public and scholars. The range of digital material covers many events and entity types, such political figures and institutions, which can be linked by many different relationship types that change over time. Domain experts often need to inspect various types of information from multiple perspectives to better analyze and grasp complex mechanisms. Our second application domain is life sciences in partnership with researchers from the environmental research and innovation department at LIST (Luxembourg Institute of Science and Technology). In recent years, the improvement in quality of practical experimental techniques has produced vast amounts of biological datasets representing many entities, such as genetic material, proteins and metabolites frequently modeled as multi-level networks. Biological systems are very complex and the levels rarely work in isolation. The experiences and problems in both application domains offer exciting new challenges and opportunities for the development of novel visual analytics (VA) solutions to provide useful tools to experts in each application domain.

Overall, existing VA approaches are limited and cannot be directly used to model complex real-world systems and fully capture their intricacy. Moreover, current visualizations of dynamic and multilayer networks do not convey temporal changes effectively. Thus, new interactive representations need to be investigated to better understand how such (potentially large-scale) networks are structured and evolve over time. The challenges are on the one hand that these networks may model complex phenomena involving multiple dimensions, which makes the analysis and tracking of changes difficult. On the other hand, although there are many ways to represent networks, designers still may not be sure which technique should be used in a given context.

Our first objective is to contribute novel graph visualizations that support the analysis and comprehension of dynamic multilayer network datasets. An important part of this objective is to build a clear understanding of the specific types of tasks that are applicable to multilayer network datasets. These tasks will need to be validated with end users and our novel visualizations evaluated in user studies. A second objective is to craft novel and interactive representations of dynamic and multilayer networks, by designing and combining visualizations. We will adopt an iterative process, mapping the problems of application domain expert users to multilayer dynamic network abstractions, then to interactive visualizations steered by domain experts. The proposal thus aims at expanding the state of the art on dynamic and multilayer network visualizations, by exploring, designing and evaluating new ways of representing these types of networks. We will contribute to (1) exploring and classifying homogeneous and hybrid approaches to visualize dynamic and multilayer networks, (2) designing novel interactive prototypes to explore some of these visualizations, and (3) evaluating these approaches in practice using case studies and user evaluations in the domains of digital cultural heritage and life sciences.

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BLIZAAR organization and work program: