Target State Estimation in a Multitarget Environment Using Multiple Sensors

An approach for target detection/state estimation that views theproblem as one of a finite state search over the target parameterspace is presented. This approach allows for a natural way toassociate different types of measurements, such as frequency andcoherence from multiple sensors, and also for dealing with multipletargets, dropouts, and clutter. We describe our model and present acomputationally efficient search algorithm for target detection andtarget state estimation in a multitarget environment based on thismodel. The results of a two-sensor, multitarget computer simulationare discussed.     

Multimodule parallel series-loaded resonant converters

The design and implementation of a multimodule parallel series-loaded resonant (SLR) converter system is presented. The SLR converter to be paralleled is operated in the n=2 discontinuous mode (DCM). Its dc analysis and dynamic modeling are made. In parallel operation, an average control technique is proposed to compensate the mismatch in current control characteristics of each parallel converter. Good dynamic and static current sharing characteristics are obtained. In addition, to obtain good output voltage regulating control performance, a design procedure is presented to find the parameters of feedback voltage controller according to the prescribed specifications     

Spatio-temporal pattern recognition using hidden Markov models

A spatio-temporal method for identifying objects contained in an image sequence is presented. The Hidden Markov Model (HMM) technique is used as the classification algorithm, making classification decisions based on a spatio-temporal sequence of observed object features. A five class problem is considered. Classification accuracies of 100% and 99.7%, are obtained for sequences of images generated over two separate regions of viewing positions. HMMs trained on image sequences of the objects moving in opposite directions showed a 98.1% successful classification rate by class and direction of movement. The HMM technique proved robust to image corruption with additive correlated noise and had a higher accuracy than a single-look nearest neighbor method. A real image sequence of one of the objects used was successfully recognized with the HMMs trained on synthetic data. This study shows the temporal changes that observed feature vectors undergo due to object motion hold information that can yield superior classification accuracy when compared with single-frame techniques     

Element and Isotopic Fractionation in Closed Magnetic Structures

Recent papers have suggested that the slow solar wind is a super-position of material which is released by reconnection from large coronal loops. This reconnection process is driven by large-scale motions of solar magnetic flux driven by the non-radial expansion of the solar wind from the differentially rotating photosphere into more rigidly rotating coronal holes. The elemental composition of the slow solar wind material is observed to be fractionated and more variable than the fast solar wind from coronal holes. Recently, it has also been reported that fractionation also occurs in 3He/4He. This may be interpreted in the frame-work of an existing model for fractionation on large coronal loops in which wave-particle interactions preferentially heat ions thereby modifying their scale-heights. This revised version was published online in June 2006 with corrections to the Cover Date.     

The Collision of Comet Shoemaker-Levy 9 with Jupiter

The discovery of Comet Shoemaker-Levy 9 in March 1993 opened an extraordinary few years in the study of the history of impacts in the solar system. This review paper offers a background that attempts to set the events of 1993 and 1994 into a historical context, and describes events leading to the discovery and the mounting of a unique and unprecedented international effort to observe the comet's collision with Jupiter. A selection of the results is presented to explore how the fate of Comet Shoemaker-Levy 9 has affected scientific and popular understanding of impacts in the solar system.     

J. A. Docobo,A. Elipe,and H. A. McAlister (eds.), Visual Double Stars: Formation,Dynamics and Evolutionary Trucks

Space Science Reviews -     

Mismatched filtering of odd-periodic binary sequences

Binary sequences with perfect periodic autocorrelation functions, as required in communications, radar, and measuring, are not known for any lengths >4. As a possible remedy, mismatched filtering can be used to entirely suppress any sidelobes of the periodic autocorrelation function at the expense of a reduced signal-to-noise ratio (SNR). In this work, the mismatched filtering method is extended to the odd-periodic autocorrelation function whose technical implementation is no more complex than that of periodic sequences. A new class of odd-periodic binary sequences is constructed that exist for many more lengths and exhibit significantly lower mismatched filtering losses than any known periodic sequences