We analyze the performance of a cell averaging constant false alarm rate (CA-CFAR) receiver that operates in a heavy-tailed clutter environment that is modeled by an alpha-stable distribution. Stable distributions are...
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We analyze the performance of a cell averaging constant false alarm rate (CA-CFAR) receiver that operates in a heavy-tailed clutter environment that is modeled by an alpha-stable distribution. Stable distributions are usually characterized with known characteristic function but their probability distribution are not known in closed form except for some special cases of the characteristic exponent α. Therefore, previous performance studies of CFAR in alpha-stable clutter have been limited to only some very special cases of α that correspond to the Gaussian, Cauchy and Pearson distributions, for which the statistical distribution of the clutter is available in closed-form. In this paper, we derive the distribution of the receiver output for arbitrary values of α in terms of the Fox's H-function. The derived statistical distribution is useful in evaluating the false alarm and detection probabilities of the system.
Neurotechnologies based on electroencephalography (EEG) and other physiological measures to improve task performance in complex environments will require tools and analysis methods that can account for increased envir...
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ISBN:
(纸本)9781479903573
Neurotechnologies based on electroencephalography (EEG) and other physiological measures to improve task performance in complex environments will require tools and analysis methods that can account for increased environmental noise and task complexity compared to traditional neurosciencelaboratory experiments. We propose a bag-of-words (BoW) model to address the difficulties associated with realistic applications in complex environments. In this paper, our proof-of-concept results show that a BoW classifier can discriminate two task-relevant states (high versus low task-load) while an individual performs a simulated security patrol mission with complex, concurrent tasking. Classifier performance is largely consistent across six simulation missions for a given participant, but performance decreases when trying to predict between two individuals. Overall, these initial results suggest that this BoW approach holds promise for detecting task-relevant states in real-world settings.
A Python computer program for calculation of distortion in the wide-band diode bridge track and hold amplifier (THA) is proposed. The computer program calculates the distortion of weekly nonlinear THA based on the KCL...
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We present an adhesive bonding process to fabricate on-chip, double-layer, single crystalline silicon nanomembranes. Inter-layer coupling efficiency of 25% with 35 nm 3dB bandwidth is demonstrated using subwavelength ...
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We present an adhesive bonding process to fabricate on-chip, double-layer, single crystalline silicon nanomembranes. Inter-layer coupling efficiency of 25% with 35 nm 3dB bandwidth is demonstrated using subwavelength nanostructure based grating couplers.
We propose a methodology for the fast analysis of the EM fields generated by the transmit radio-frequency coils when operating in the presence of realistic human body models (RHBM). This work is driven by the need of ...
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ISBN:
(纸本)9781467357067
We propose a methodology for the fast analysis of the EM fields generated by the transmit radio-frequency coils when operating in the presence of realistic human body models (RHBM). This work is driven by the need of fast and accurate specific absorption rate (SAR) prediction and coil design analysis in the context of high-field Magnetic Resonance Imaging (MRI). These RHBM are highly inhomogeneous voxelized models, whose EM analysis can be expensive. In our approach, the electromagnetic effect of the complex RHBM is captured by a numerically generated Green function (GF). For MRI problems, the electric current sources are generally confined to a very small region where the coils could be located. The RHBM GF is required only for that specific source region and can therefore be effectively pre-computed and stored. These GF can be then assembled and combined with standard surface integral equation based solvers to model the actual coil design, allowing for a fast analysis of the complete problem.
We demonstrate an Yb-fiber oscillator based, broadband (~170 nm) laser source centered at 850 nm. The spectrum generated by fiber-optic Cherenkov radiation produces ~11-fs compressed pulses after phase compensation us...
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ISBN:
(纸本)9781467364751
We demonstrate an Yb-fiber oscillator based, broadband (~170 nm) laser source centered at 850 nm. The spectrum generated by fiber-optic Cherenkov radiation produces ~11-fs compressed pulses after phase compensation using 8 double-chirped mirrors.
We report the fabrication and characterization of ultrafast laser triggered nanostructured silicon photo-cathodes for x-ray generation via inverse Compton scattering. A highly uniform array of ~2200 silicon pillars wi...
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We report the fabrication and characterization of ultrafast laser triggered nanostructured silicon photo-cathodes for x-ray generation via inverse Compton scattering. A highly uniform array of ~2200 silicon pillars with 5 μm array pitch, where each pillar is capped by a nanosharp tip, shows stable current emission using 35 fs, 800 nm laser pulses. The cathodes can emit at 3.6 nA average current over 8-million 1.2 pC electron bunches when excited with 9.5 μJ laser pulses with no degradation of the emission characteristic of the cathode, showing that silicon-based photon-triggered cathodes processed with standard CMOS processes and operated at high vacuum can function for extended periods without performance degradation.
We investigate second-harmonic generation, low-threshold multistability, all-optical switching, and inherently nonlocal effects due to the free-electron gas pressure in an epsilon-near-zero (ENZ) metamaterial slab mad...
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We investigate second-harmonic generation, low-threshold multistability, all-optical switching, and inherently nonlocal effects due to the free-electron gas pressure in an epsilon-near-zero (ENZ) metamaterial slab made of cylindrical, plasmonic nanoshells illuminated by TM-polarized light. Damping compensation in the ENZ frequency region, achieved by using gain medium inside the nanoshells’ dielectric cores, enhances the nonlinear properties. Reflection is inhibited, and the electric field component normal to the slab interface is enhanced near the effective pseudo-Brewster angle, where the effective ɛ≈0 condition triggers a nonresonant, impedance-matching phenomenon. We show that the slab displays a strong effective, spatial nonlocality associated with leaky modes that are mediated by the compensation of damping. The presence of these leaky modes then induces further spectral and angular conditions, where the local fields are enhanced, thus opening new windows of opportunity for the enhancement of nonlinear optical processes.
We develop a reduced model using 100 single-shot simulations for the output spectrum from a supercontinuum source using an As 2 S 3 photonic crystal fiber that qualitatively matches the ensemble averaged spectrum exp...
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We develop a reduced model using 100 single-shot simulations for the output spectrum from a supercontinuum source using an As 2 S 3 photonic crystal fiber that qualitatively matches the ensemble averaged spectrum expected in an experiment.
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