DD(X) will require reduced manning of the sonar watch stations to meet its goal of overall reduced manning. However, passive sonar analysis is manpower intensive, particularly in analysis of broadband, narrowband, and LOFAR data. We propose to utilize the technique of Case Based Reasoning to assist passive sonar operators. Case Based Reasoning fits this problem particularly well because, while passive sonar analysis is very experience dependent, subjective, and difficult to reduce to firm rules, there are many interpreted data cases available. This is the type of application for which Case Based Reasoning was developed. Case Based Reasoning operates by extracting from the case library cases most similar to the current data, evaluating those cases to determine how they fit the current data, and adapting the current data case into the case library. Case Based Reasoning is currently being used in a broad range of analysis-heavy applications such as medical diagnosis and mechanical diagnosis, so we consider this to be a very feasible approach
