David Crouse

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The objective of this paper is to model determinants of intraurban variation in ambient concentrations of nitrogen dioxide (NO2) in Toronto, Canada, with a land use regression (LUR) model. Although researchers have conducted similar studies in Europe, this work represents the first attempt in a North American setting to characterize variation in traffic(More)
Mobile devices can carry large amounts of personal data, but are often left unsecured. PIN locks are inconvenient to use and thus have seen low adoption (33% of users). While biometrics are beginning to be used for mobile device authentication, they are used only for initial unlock. Mobile devices secured with only login authentication are still vulnerable(More)
A rigorous method of modeling the performance of metal-semiconductor-metal photodetectors (MSM-PD) that use several electromagnetic resonance (ER) modes and optical modes to enhance performance is presented. These ER and optical modes include surface plasmons, Wood-Rayleigh anomalies and vertical cavity modes. Five modeling algorithms are integrated(More)
In this work, it is shown how the shapes of surface plasmon dispersion curves can be engineered by manipulating the distribution of the electromagnetic fields in multilayer structures, which themselves are controlled by the free electron density in metal-like materials, such as doped semiconductors in the THz spectral range. By having a nonuniform free(More)
A review and analysis is performed of various resonance effects associated with subwavelength one-dimensional (1-D) metal gratings for transverse electric (TE) and transverse magnetic (TM) polarized incident radiation. It is shown that by tuning the structural geometry (especially the groove width) and material composition of the 1-D gratings, polarization(More)
Lemurs are a unique and diverse group of primates that are endemic to the island of Madagascar. Unfortunately, they are also the world’s most endangered mammals. Habitat loss, hunting pressure, and illegal trafficking for the pet trade are ongoing threats, and population numbers for most lemur species are declining. In order to implement effective(More)
A periodically patterned metal-dielectric composite material is designed, fabricated and characterized that spatially splits incoming microwave radiation into two spectral ranges, individually channeling the separate spectral bands to different cavities within each spatially repeating unit cell. Further, the target spectral bands are absorbed within each(More)
An analysis of several types of one-dimensional transmission gratings structures with different metal contact geometries is used to study the role of horizontally oriented surface plasmons, cavity modes and other optical modes in enhanced transmission. Several competing theories of enhanced transmission are presented and the analysis of the structures in(More)
Beam steering has been traditionally achieved by mechanical means. Even though these mechanical techniques have evolved over the past few decades, non-mechanical approaches, due to benefits such as increased speed, lower costs and reduced complexity, have gained considerable interest. In this work, we propose a non-mechanical beam steering of terahertz(More)