to which they belong that are sensitive to the geo-temporal-cultural context (Keller-McNulty et al., 2006). These methods make extensive use of network science and theory. Data comes from text, gazetteers, maps, and other sources. Often techniques examine links between elements, such as members of social groups or tribes, or identify critical points in networks, such as sequences of ports-of-call for vessels or vulnerable points in network traffic (Prietula et al., 1998). Many different visual display methods are used to examine the networks for these points. Challenges stated by Dr. Carley were getting social scientists to use the many available tools, access to geo-tools such as open-source geobrowsers, combining spatial and social models, the incompleteness of social data and the lack of a central theory, and the accuracy and reliability of self-reported data.
Working Group Reports. In the working group discussions, research issues of interest included the integration and fusion of social data, especially given the modifiable area unit problem and ecological fallacy; the lack of accurate GPS point traces on individuals, and hence reliance on census and other data sources; the need to integrate highly disparate data on economy, sociology, transportation, anthropology, ethnicity, religion, culture, and history; and the large differences in data certainty and reliability.
Fusion challenges identified by the working group participants were integrating data across spatial scales; dealing with semantic interoperability; conflation; dealing with sensors with different resolutions or spatial frameworks; and integrating at the data, information, and knowledge levels. Workshop participants also indicated that data fusion needs are still critical in remote sensing and are complicated by sensor networks. Sensor level fusion, using techniques such as support vector machines and Bayesian modeling, seem to be making advances, but the fusion of hard and soft data is still an unsolved problem. The role of humans as agents of data fusion was thought to be in need of study.
Specific topics outlined by the working groups are summarized in Appendix E.