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A common problem in human movement recognition is the recognition of movements of a particular type (semantic). E.g., grasping movements have a particular semantic (grasping) but the actual movements usually have very different appearances due to, e.g., different grasping directions. In this paper, we develop an exemplar-based parametric hidden Markov model (PHMM) that allows to represent, e.g., movements of a particular type and that compensates for the different appearances and parameterizations of that movement. The PHMM is based on exemplar movements that have to be "demonstrated" to the system. Recognition and synthesis are carried out through locally linear interpolation of the exemplar movements. For a meaningful interpolation, the exemplars have to be in sync, what exhibits certain problems that are resolved in this paper. In our experiments we combine our PHMM approach with our 3D body tracker. Experiments are performed with pointing and grasping movements. Synthesis for grasping is parameterized by the positions of the objects to be grasped. In case of recognition, our approach is able to recover the position of an object at which a human volunteer is pointing. Our experiments show the flexibility of the PHMMs in terms of the amount of training data and its robustness in terms of noisy observation data. In addition, we compare our PHMM to an other kind of PHMM, which has been introduced by Wilson and Bobick.

The challenging demands of pulsed electron beam devices (such as the GESA device) with respect to their pulsed power supply have lead to the development of a new semiconductor-based Marx generator. At a maximum output voltage of 120 kV and 600 A pulse current for a duration of up to 100 µs, step-wise arbitrary output waveforms are desired. A fast rise time of the generator is achieved by using fast switching circuitry, low inductance capacitors and a low inductance stage arrangement. For low jitter triggering of all stages and efficient signal transmission, the generator uses an optical bus system for communication. Due to the inherent dynamic load characteristics of the GESA device, the generator features a fast over-current protection scheme. This work presents selected design aspects of the generator and their validation in a small-scale assembly able of delivering up to 8 kV at 600 A load current.

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