Defence Science and Technology Organisation

About: Defence Science and Technology Organisation is a nonprofit organization based out in Canberra, Australian Capital Territory, Australia. It is known for research contribution in the topics: Radar & Clutter. The organization has 2465 authors who have published 3856 publications receiving 90614 citations.

Non-stationary time series analysis — MT applications

Abstract: The EMSLAB data set (Jones et al., 1989) has been processed using time-frequency methods to estimate the apparent resistivities and phases. When compared to the results from traditional methods, the time-frequency analysis has produced different apparent resistivity estimates for the noisier component, while the phases and the apparent resistivity estimates for the component with the stronger signal are very similar. This is consistent with the bias being due to nonstationary effects, and could indicate that this type of analysis will significantly improve the quality of magnetotelluric data.

High resolution long range isar imaging systems

Abstract: The requirements for high resolution, long range ISAR imaging systems capable of recognising targets have been outlined. Systems meeting these requirements and operating at mm-wavelengths have been proposed. The systems consist of N phased locked transmitters feeding as many antennas in phase. Quasi-optical power addition at the target occurs. In the receive mode all antennas are connected in phase. These systems can at least double the range obtained by utilising a system having one transmitter/antenna combination. Several realisation options have been studied including the annular synthesis antenna systems which offer some advantages over more conventional realisations.

Influence of laser processing parameters on microstructure and corrosion of laser surface melted ZE41 magnesium alloy

Abstract: In the present study, surface melting of a magnesium alloy, ZE41, was performed with an Nd:YAG laser, using different laser parameters (scan rate and beam type). The microstructure of the laser treated and untreated specimens were characterised by optical and scanning electron microscopy. The degree of microstructural refinement and melt depth was found to be a function of the laser scan rate. Electrochemical characterisation of the different laser treated specimens along with the untreated alloy was performed using electrochemical impedance spectroscopy. The laser treated specimens and untreated alloy showed similar corrosion resistance.

Improving network performance using active remote node in EPON

Abstract: A simple layer two forwarding scheme is proposed for EPON with active remote node (RN) to increase the network efficiency. The simulation results show a large improvement in latency and capacity with active RN structure without affecting EPON protocol.

Explosives sensing based on suspended core fiber coated with conjugated polymer

Abstract: Suspended core fibers with voids surrounding the core coated with conjugate polymer were used to detect nitroaromatic explosives based on the fluorescence quenching technique. The background Raman signal from a suspended core fiber was used as reference to optimize coupled into the core of the fiber. The fluorescence spectra were integrated across all wavelengths to extract the integrated fluorescence intensity at regular time intervals. Fluorescence decay lifetimes were obtained by fitting a single exponential decay and were used to detect 1,4-dinitrobenzene (DNB), a member of the nitroaromatics family of explosives, in acetone solutions at concentrations as low as 6.3 ppm.