Digitalization throughout the industry leads to rapidly increasing amounts of data captured and stored which brings forth challenges for indexing and ac- cessing large digital repositories. Very often, the data takes form of complex multi-part entities, such as images with relational attributes, photos with ge- ographical coordinates or textual posts with multimedia content and implicit social relationships. The complexity of such entities and lack of fixed struc- ture makes it impossible to use classical information retrieval methods based on attribute filtering, ranking or grouping, as it is not easy or sometimes even possible to define an exact query. In this thesis, we target data exploration as an act of exploring an unfamiliar area via a series of intuitive, effective and efficient system-supported steps. We present methodologies, demo applications and evaluation results targeting different data sources of multimedia data. Fur- thermore, we focus on the ability to utilize multiple modalities within a single session and on integrating the results into widely used software solutions.

Since the early nineteenth-century when Americans began recording their short history in earnest, European explorers have held a central role in the nation's historical narrative, standing alongside the Founding Fathers as symbols of American ingenuity, determination, and fortitude. The nineteenth century also saw an explosion in the number of representations of first contacts between native populations and European and Euro-American explorers. These works range from fine art examples to illustrations in the popular media and were produced by artists across the artistic spectrum. Despite the popularity of the First Contact subject and its longevity within American art history, the importance of these images has, as of yet, been unexplored. This dissertation examines First Contact images created in America during the nineteenth and early twentieth-century by artists Robert Walter Weir, George Catlin, Thomas Moran, Albert Bierstadt, and Charles M. Russell. I argue that the subject's popularity can be attributed not just to their importance as depictions of epic moments of transition in national and cultural history, but to the openness, or the mutability, of the subject itself. The first meeting of two people is an event of great possibility and potential, but, as this extended examination of the subject demonstrates, it can also be transformed to communicate vastly different messages at different moments in history. As Americans simultaneously struggled to create a past, understand the present, and visualize the future, the First Contact subject, with its focus on the ambiguous meeting of two cultures, allowed a site in which to grapple with central questions and anxieties of the period, even as it depicted the past. They are thus complicated paintings that speak not to the facts of contact, but to the purposes served by these constructions and corrupted histories. Reading these First Contact paintings can help to illuminate a nineteenth-century understanding of history and also begin to elucidate the troubled legacy of Native/white relations since Columbus first encountered the New World.