Thomas Higgins

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We consider a class of MIMO radar emissions in which a coherent spatial beam is formed while the direction is modulated during the pulse width. This type of spatial modulation has a direct analog to the rapid, small movements of the human eye during fixation (staring) to enhance contrast and sensitivity to fine detail. To replicate this passive sensing(More)
In three experiments, rats received pairings of flavor conditioned stimuli with polycose unconditioned stimuli, in either a simultaneous or a sequential relation. Both temporal relations produced excellent conditioned increases in consumption of the flavors. Separate presentation of the flavors resulted in extinction in both cases. However, restoring the(More)
This article describes novel phase-separation behavior by a binary mixture of alkanethiols when deposited onto a gold surface using micro- and nanodeposition tools, such as microcontact printing (muCP) and dip-pen nanolithography (DPN). This behavior is significantly different than that observed in the bulk. We demonstrate this behavior using three model(More)
A new spectral-shaping approach is used to design jointly the amplitude window and phase of a tapered NLFM waveform. This approach can produce physical radar emissions with ultra-low sidelobes that support sufficient spectral roll-off to maintain forthcoming spectral compliance requirements. A small SNR loss is traded for a substantial reduction in range(More)
Waveform-diverse radar arrays have been proposed as a method to facilitate single pulse imaging as well as to potentially enable simultaneous multi-mode operation. Transmitting different waveforms on the elements of a uniform linear array consequently raises the spatial and temporal sidelobes of the receiver matched filter. In this paper a recursive minimum(More)
The sensitivity impact of range straddling in the form of mismatch loss is well known. What is less appreciated, however, is the effect upon dynamic range, particularly for receive filtering that seeks to minimize range sidelobes. For FMbased waveforms, which are readily implementable in a highpower radar system, it is shown that least-squares (LS)(More)
Inspired by the fixational movements of the human eye, fast-time spatial modulation was recently demonstrated as a particular physically realizable form of a multiple-input multiple-output (MIMO) radar emission. The attendant coupling of the delay and angle dimensions has been shown to provide a modest improvement in spatial separation, even when using(More)
Mononuclear, dinuclear, and polymeric Ru(II) complexes formed from terthienylalkylphosphino redox-switchable hemilabile ligands demonstrate that this class of ligand provides electrochemical control over the electronic properties, coordination environments, and reactivities of bound transition metals. Specifically,(More)
Gradient descent is an iterative method of determining the minima or maxima of a function. The algorithm can be used to solve a linear system of equations when the computational cost of a matrix inverse is too expensive for an application. Here, gradient descent is applied to Adaptive Pulse Compression (APC), yielding the GraD-APC algorithm. Specifically, a(More)