The document summarizes Serwah Sabetghadam's PhD defense presentation on a graph-based model for multimodal information retrieval. The key points are:
1) It proposes a graph model called Astera to support different modalities, relation types, and faceted representations of information objects for multimodal IR.
2) A hybrid search approach is used that combines standard searches with graph traversal on the Astera model.
3) An example query on images of flying birds is presented to illustrate how the collection is modeled and searched using the proposed approach.