Gough, M. P. | Search NASA

NASA NTRS1995

PULSAUR 2: A sounding rocket project to study pulsating aurora and related phenomena

The second pulsating aurora (PULSAUR 2) rocket was a comprehensively instrumented rocket for the study of the generating mechanisms of pulsating auroras and their related atmospheric and ionospheric effects. It carried instruments to measure electrons and ions over a wide range of energies and pitch angles, optical emissions and X-rays, direct currents and alternating currents, magnetic fields, electron densities and temperatures. The rocket was flown from Andoeya, Norway on 9 February 1994, during good auroral and optical conditions, and reached an altitude of 291.5 km. Coordinated measurements were made from the rocket range by television cameras, photometers, magnetometers, riometers and very low frequency receivers. Ionospheric parameters were measured by the EISCAT radar. The main objectives and performance of the project are discussed, and some of the data obtained are mentioned.

Maaseide, K.↗

NASA NTRS1995

Geophysical phenomena classification by artificial neural networks

Space science information systems involve accessing vast data bases. There is a need for an automatic process by which properties of the whole data set can be assimilated and presented to the user. Where data are in the form of spectrograms, phenomena can be detected by pattern recognition techniques. Presented are the first results obtained by applying unsupervised Artificial Neural Networks (ANN's) to the classification of magnetospheric wave spectra. The networks used here were a simple unsupervised Hamming network run on a PC and a more sophisticated CALM network run on a Sparc workstation. The ANN's were compared in their geophysical data recognition performance. CALM networks offer such qualities as fast learning, superiority in generalizing, the ability to continuously adapt to changes in the pattern set, and the possibility to modularize the network to allow the inter-relation between phenomena and data sets. This work is the first step toward an information system interface being developed at Sussex, the Whole Information System Expert (WISE). Phenomena in the data are automatically identified and provided to the user in the form of a data occurrence morphology, the Whole Information System Data Occurrence Morphology (WISDOM), along with relationships to other parameters and phenomena.

Gough, M. P.↗