Variational inference (VI) is an approximation of statistically valid Bayesian inference which is well-suited for analog accelerators, and stochastic nanomagnetic devices in particular are a strong candidate to implement this feature by exploiting tunable randomness in magnetic thin-films that can be run quickly and with a low power-draw. In this work, we a) discuss how VI can be reliably implemented with a combination of low-noise nanomagnetic synapses and tunable noise generating sources (magnetic tunnel junctions (MTJs) in a single analog design and b) summarize efforts to characterize the state-dependent noise profiles of various MTJ designs for various applications.
Iron oxide colloidal nanocrystals (ferrofluids) are investigated for application in the treatment of cystic fibrosis lung
infections, the leading cause of mortality in cystic fibrosis patients. We investigate the use of iron oxide nanocrystals to
increase the effectiveness of inhalation aerosol antibiotics therapy through two mechanisms: directed particle movement
in the presence of a static external magnetic field and magnetic hyperthermia. Magnetic hyperthermia is an effective
method for decreasing the viscosity of the mucus and biofilm thereby increasing drug, immune cell, and antibody
penetration to the affected area. Iron oxide nanocrystals of various sizes and morphologies were synthesized and tested
for specific losses (heating power) using frequencies of 111.1 kHz and 629.2 kHz, and corresponding magnetic field
strengths of 9 and 25 mT. Nanocrystals in the superparamagnetic to ferromagnetic size range exhibited excellent heating
power. Additionally, iron oxide-zinc selenide core-shell nanoparticles were prepared in parallel in order to allow
imaging of the iron oxide nanoparticles.
Scannerless laser radar (LADAR) is the next revolutionary step in laser radar technology. It has the potential to dramatically increase the image frame rate over raster-scanned systems while eliminating mechanical moving parts. The system presented here uses a negative lens to diverge the light from a pulsed laser to floodlight illuminate a target. Return light is collected by a commercial camera lens, an image intensifier tube applies a modulated gain, and a relay lens focuses the resulting image onto a commercial CCD camera. To produce range data, a minimum of three snapshots is required while modulating the gain of the image intensifier tube's microchannel plate (MCP) at a MHz rate. Since November 1997 the scannerless LADAR designed by Sandia National Laboratories has undergone extensive testing. It has been taken on numerous field tests and has imaged calibrated panels up to a distance of 1 km on an outdoor range. Images have been taken at ranges over a kilometer and can be taken at much longer ranges with modified range gate settings. Sample imagery and potential applications are presented here. The accuracy of range imagery produced by this scannerless LADAR has been evaluated and the range resolution was found to be approximately 15 cm. Its sensitivity was also quantified and found to be many factors better than raster- scanned direct detection LADAR systems. Additionally, the effect of the number of snapshots and the phase spacing between them on the quality of the range data has been evaluated. Overall, the impressive results produced by scannerless LADAR are ideal for autonomous munitions guidance and various other applications.
Sandia National Laboratories has developed a unique type of portable low-cost range imaging optical radar (laser radar or LADAR). This innovative sensor is comprised of an active floodlight scene illuminator and an image intensified CCD camera receiver. It is a solid-state device (no moving parts) that offers significant size, performance, reliability, and simplicity advantages over other types of 3D imaging sensors. This unique flash LADAR is based on low- cost, commercially available hardware, and is well suited for many government and commercial uses. This paper presents an update of Sandia's development of the Scannerless Range Imager technology and applications, and discusses the progress that has been made in evolving the sensor into a compact, low cost, high-resolution, video rate Laser Dynamic Range Imager.
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