Antony C. Fraser-Smith

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1 2 Abstract This paper presents new measurements of the magnetic field component of naturally–produced electromagnetic radiation in the ELF/VLF range. The measurements are compared to calculations based on modal propagation theory. The nocturnal spectrum below 5 kHz often contains a sharp increase in spectral level at the cutoff frequency of the first mode(More)
We consider the detection in the presence of 1=f noise of a known transient signal of unknown amplitude, scale and delay. We introduce a generalized likelihood ratio test (GLRT) method based on pattern matching in the undec-imated discrete wavelet transform (UDWT) domain. In many cases, the computational complexity of the detector can be reduced with(More)
We address the problem of identifying and removing man-made transients from geomagnetic time series acquired with an array of magnetometers. We model the tran-sients as scaling functions of unknown scales, amplitudes, and delays. We then use an undecimated discrete wavelet transform to identify the transients in the presence of the natural 1=f geomagnetic(More)
A single culture of Chlorella pyrenoidosa (700 ml) was grown continuously under uniform environmental conditions for a period of 11 months. During this time, the culture remained uncontaminated and its oxygen production, carbon dioxide consumption, and photosynthetic quotient (PQ = CO(2)/O(2)) were monitored on a 24-hr basis. The gas exchange(More)
The specific long-term goal of this project is to provide the Navy with greatly improved information about the characteristics of both natural and man-made radio noise and signals in the ELF/VLF bands (frequencies in the range 10 Hz to 32 kHz), with the object of improving the Navy's ELF/VLF radio communications. SCIENTIFIC OBJECTIVES The project has two(More)