Defence Research Agency

About: Defence Research Agency is a based out in . It is known for research contribution in the topics: Synthetic aperture radar & Radar. The organization has 1211 authors who have published 1109 publications receiving 31542 citations.

Preparation of metal-aromatic diamine complexes and their influence on the cure of a commercial epoxy resin

Abstract: The preparation of metal-aromatic diamine complexes is reported along with their characterisation by infrared spectroscopy. Dynamic viscometry (gel-point determination) was used to assess the reactivity of some of the metal-diamine complexes with a commercial epoxy resin. Significant differences were observed in the viscosity profiles for formulations with different metal contents. These related to the reactivities of the diamines which are themselves a function of metal content.

Nonlinear feature extraction with radial basis functions using a weighted multidimensional scaling stress measure

Abstract: We investigate radial basis functions for nonlinear feature extraction. The parameters of the transformation are determined by minimising a loss term (similar to stress in multidimensional scaling) that weights components of the loss by a nonlinear function of the dissimilarities. Several forms for the nonlinear function are considered and an optimisation scheme based on iterative majorisation is used to determine the parameter values. The technique is illustrated on two data sets.

The UoSAT-5 solar cell experiment: First year in orbit

Abstract: The results for the first year in orbit of the DRA solar cell experiment flying on the Surrey University UoSAT-5 satellite are described. Several problems were identified with the measured data, which are discussed along with the techniques used to remove or minimize the effect of the problems. After 1 year in orbit the majority of the cells flying on the experiment have undergone little or no degradation. The exception to this are all the ITO/InP cells, supplied by two different manufacturers, they are showing more degradation than the GaAs cells. This result is unexpected and currently unexplainable. It will be necessary to retrieve data from the experiment for several years to obtain the best results due to the relatively benign radiation environment.

The estimation of ocean current from /spl omega/-k analysis of radar data

Abstract: 2D Fourier transform analysis was carried out on radar sea clutter data. It was found that the gravity wave dispersion relation and its harmonics were clearly visible in the /spl omega/-k images. The dispersion curve and its harmonics were found to be distorted and rotated from their expected positions due to the existence of ocean currents. Measurements are made from the dispersion curves of both advancing and receding waves, and a significant difference is observed between the two measurements.