Frequently, the information collected will not be in a format ready for analysis. For example, consider the collection of electronic health records in a hospital, composed of transcribe dictations from several physicians, structured data from sensors and measurements (possibly with some associated uncertainty), image data such as X-rays, and videos from probes. We cannot leave the data in this form and still effectively analyze it. Rather, we require an information extraction process that pulls out the required information from the underlying sources and expresses it in a structured form suitable for analysis.