The purpose of this work is to study the impact due to individual vector sensor element steering patterns on linear array beamforming. Standard, linear beamformers employ cardioid beampatterns for each vector sensor. In this work, a class of vector sensor element steering patterns beyond the standard cardioid was examined. The element weighting is nonlinear but nonadaptive, making it simple to implement in hardware processing. The new sensor steering patterns, referred to as hippioids, are products of cardioids and various powers of hippopedes. The angular resolution of individual sensors, the impact on angular resolution from arrays of varying aperture, and peak-to-sidelobe levels will serve as performance measures. An example of the differences in vector sensor steering patterns is provided using measured directional frequency and recorded buoy data.

Diagnosis of large and complex software systems is a challenging task that can highly benefit from monitoring of the highlevel functional requirements. This work studies the potential of applying requirements monitoring for a software system of high complexity: the combat management system (CMS) of a modern and technologically advanced naval platform. An effort is made to apply the requirements monitoring method for autonomizing of this system while limiting implementation impact. The KAOS goaloriented requirements engineering method is used to extract software system goals from previously documented requirements. With these high-level objectives as a starting point, the ReqMon requirements monitoring framework is applied. An implementation model is defined, identifying what data transformations are needed to apply the ReqMon system. Tests with a requirements monitoring prototype demonstrate that detailed diagnosis of a complex software system as a CMS is feasible and furthermore that comprehensive manual fault analysis can be replaced by an automated process: the first step towards a self-healing autonomic combat management system is taken.

No abstract

The purpose of this report is to study the impact on linear beamforming due to individual vector sensor element steering patterns. Standard, linear beamformers employ cardioid beampatterns for each vector sensor. In this work, we examine a class of vector sensor element steering patterns beyond the standard cardioid. The element weighting is nonlinear but nonadaptive, making it simple to implement in hardware processing. The new sensor steering patterns, referred to as hippioids, are products of cardioids and various orders of hippopedes. The angular resolution of individual sensors, and the impact on angular resolution from arrays of varying aperture, will serve as the performance measure along with peak-to-sidelobe levels. An example of the differences in vector sensor steering patterns is provided using measured, DIFAR buoy data. [Work supported by the Office of Naval Research, Code 321OA, the Naval Postgraduate School, and the Netherlands Defense Academy.]

Chair's Introduction-7:45 Contributed Papers 7:50 5aUW1. Notes on broadband seabed geoacoustic inversion in shallow water.