Translational motion compensation of ballistic target based on radon transform
Ballistic target translational motion compensation is beneficial to motion parameter extraction. Aiming at the problem of multiple scattering points translational motion compensation, an algorithm is proposed to extract the translational motion parameters of ballistic targets based on using the projection transform of the whole micro-frequency curve by Radon transform in this paper. First, establishing and analyzing the typical ballistic target model and the expressions of scattering points' micro-frequency are solved. Second, target signal is pre-compensated based on radar information and time-frequency transform. And Radon transform is applied to the parameter projection of time-frequency curve. Then translational motion parameters are estimated based on minimum entropy criteria and gauss fitting. Finally, translational motion is compensated by making use of the estimated motion parameters. Simulation results verify the validity of the proposed algorithm.
Research on the Influence of Acceleration on Micro-Doppler and Its Compensation
Micro-Doppler provides a new feature for radar target recognition while the acceleration affects the extraction of micro-Doppler information.Under the case of micro-Doppler modulation induced by a cone-shaped target's wobble,the influence of acceleration on micro-Doppler is studied,and two methods,the peak one based on frequency spectrum and the template one based on time-frequency spectrum,are proposed to compensate the acceleration as well as the comparison between them.The simulating result shows that the two methods can effectively compensate the acceleration.
Urea removal strategies for dialysate regeneration in a wearable artificial kidney.
The availability of a wearable artificial kidney (WAK) that provides dialysis outside the hospital would be an important advancement for dialysis patients. The concept of a WAK is based on regeneration of a small volume of dialysate in a closed-loop. Removal of urea, the primary waste product of nitrogen metabolism, is the major challenge for the realization of a WAK since it is a molecule with low reactivity that is difficult to adsorb while it is the waste solute with the highest daily molar production. Currently, no efficient urea removal technology is available that allows for miniaturization of the WAK to a size and weight that is acceptable for patients to carry. Several urea removal strategies have been explored, including enzymatic hydrolysis by urease, electro-oxidation and sorbent systems. However, thus far, these methods have toxic side effects, limited removal capacity or slow removal kinetics. This review discusses different urea removal strategies for application in a wearable dialysis device, from both a chemical and a medical perspective.