Redefining Event Types and Group Evolution in Temporal Data
This work addresses the gap between theoretical event definitions and real-world group dynamics in data mining, offering a more flexible approach for researchers analyzing temporal data.
The paper tackles the problem of characterizing group evolution in temporal data by moving beyond predefined event types, introducing a framework based on quantitative facets and archetypes, and demonstrates its application on face-to-face interaction datasets for richer and more reliable analysis compared to state-of-the-art methods.
Groups -- such as clusters of points or communities of nodes -- are fundamental when addressing various data mining tasks. In temporal data, the predominant approach for characterizing group evolution has been through the identification of ``events". However, the events usually described in the literature, e.g., shrinks/growths, splits/merges, are often arbitrarily defined, creating a gap between such theoretical/predefined types and real-data group observations. Moving beyond existing taxonomies, we think of events as ``archetypes" characterized by a unique combination of quantitative dimensions that we call ``facets". Group dynamics are defined by their position within the facet space, where archetypal events occupy extremities. Thus, rather than enforcing strict event types, our approach can allow for hybrid descriptions of dynamics involving group proximity to multiple archetypes. We apply our framework to evolving groups from several face-to-face interaction datasets, showing it enables richer, more reliable characterization of group dynamics with respect to state-of-the-art methods, especially when the groups are subject to complex relationships. Our approach also offers intuitive solutions to common tasks related to dynamic group analysis, such as choosing an appropriate aggregation scale, quantifying partition stability, and evaluating event quality.