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Representation of multiwinding transformers by equivalent circuits has been recently improved, and it is for the identification of components of these circuits. In this paper, the focus is on magnetic coupling with its related losses. A general method, based on external impedance measurements, is followed to determine inductances, coupling ratios, and resistances included in these equivalent circuits. Justification for impedance measurements, choice of measured impedances, and precautions regarding short-circuit compensation are discussed.For illustration, two components are tested, and their equivalent circuits are established.

We use various laws of classical physics to offer several solutions of Yao's millionaires' problem without using any one-way functions. We also describe several informationally secure public key encryption protocols, i.e., protocols secure against passive computationally unbounded adversary. This introduces a new paradigm of decoy-based cryptography, as opposed to "traditional" complexity-based cryptography. In particular, our protocols do not employ any one-way functions.

In this paper, we present a numerical approach for predicting fluid flows in solid rocket motor (SRM) chambers. We use a novel high-order technique to track the burning grain surface. Spectral convergence toward the exact burning surface is achieved thanks to Fourier differentiation. In addition, we make use of a body-fitted mesh deforming with the burning surface and present a method to avoid manual remeshing. We describe several methods to deform the volume mesh and to keep good mesh element quality during the computation. We then couple the surface and volume approaches. The resulting coupled method is able to handle the formation of geometric singularities on the burning surface while keeping constant surface and volume mesh topology. This geometrical approach is integrated into a complex code for compressible, multi-species, turbulent flow simulations. Applications to the simulation of the internal flow in realistic solid rocket motors with complex grain geometry are then presented.

By taking advantage of the interaction between terahertz polarization and carbonfiber orientation, impact-induced intra-and inter-laminar damages at the same interface are differentiated via terahertz polarization-resolved imaging in three dimensions.

We propose an efficient method that determines the sign of a multivariate polynomial expression with integer coefficients. This is a central operation on which the robustness of many geometric algorithms depends. Our method relies on modular computations, for which comparisons are usually thought to require multiprecision. Our novel technique of {\it recursive relaxation of the moduli} enables us to carry out sign determination and comparisons by using only floating point computations in single precision. This leads us to propose a hybrid symbolic-numeric approach to exact arithmetic. The method is highly parallelizable and is the fastest of all known multiprecision methods \from a complexity point of view. As an application, we show how to compute a few geometric predicates that reduce to matrix determinants and we discuss implementation efficiency, which can be enhanced by arithmetic filters. We substantiate these claims by experimental results and comparisons to other existing approaches. Our method can be used to generate robust and efficient implementations of geometric algorithms (convex hulls, Delaunay triangulations, arrangements) and numerical computer algebra (algebraic representation of curves and points, symbolic perturbation, Sturm sequences and multivariate resultants).

The spectral width observed by Doppler radars can be due to several effects including the atmospheric turbulence within the radar sample volume plus effects associated with the background flow and the radar geometry and configuration. This study re-examines simple models for the effects due to finite beamwidth and vertical shear of the horizontal wind. Analytic solutions of 1- and 2-dimensional models are presented. Comparisons of the simple 2-dimensional model with numerical integrations of a 3-dimensional model with a symmetrical Gaussian beam show that the 2-dimensional model is usually adequate. The solution of the 2-dimensional model gives a formula that can be applied easily to large data sets. Analysis of the analytic solutions of the 2-dimensional model for off-vertical beams reveals a term that has not been included in mathematical formulas for spectral broadening in the past. This term arises from the simultaneous effects of the changing geometry due to curvature within a finite beamwidth and the vertical wind shear. The magnitude of this effect can be comparable to that of the well-known effects of beam-broadening and wind shear, and since it can have either algebraic sign, it can significantly reduce (or increase) the expected spectral broadening, although under typical conditions it is smaller than the beam-broadening effect. The predictions of this simple model are found to be consistent with observations from the VHF radar at White Sands Missile Range, NM.

An abundance of research has demonstrated that the brain is both organized into discrete, highly specialized, regions and that distributed regions work together in the form of large-scale networks. It remains unclear, however, how to reconcile these two views of brain function. In this thesis, I present several projects that investigated the specialized properties of individual regions, how these change depending on cognitive demands and external disruption, and how these changes interact with modulations across large-scale networks. Across these projects, I use a combination of methods including psychophysics, univariate and multivariate modeling of functional Magnetic Resonance Imaging (fMRI) data, Transcranial Magnetic Stimulation (TMS), and the study of patients with focal lesions. The first section of this thesis focuses on visual attention to high-level face stimuli. Here, I demonstrate that highly specialized representations exist for individual faces, but that engaging in sustained top-down attention can cause selective modulations in these representations. This suggests that large-scale networks can interact with, and modify, the properties of local regions in an extremely selective manner. The second section of the thesis examines how disrupting local regions, through focal brain lesions or TMS, impacts the structure of large-scale networks. The first two chapters in this section examine how acute and chronic disruptions modulate the magnitude of interactions throughout cognitive control networks. An additional project explores methodological considerations involving the variability in TMS effects and how these might be measured most effectively. The final project in this section examines how focal brain lesions also affect the organization of distributed networks. This section illustrates how the properties of local regions can modulate both the magnitude and organization of distributed networks.In sum, these projects demonstrate that large-scale networks can both drive and be driven by the highly specialized properties of local regions. This research will hopefully provide some insight into how brain regions may concurrently demonstrate highly specialized brain activity and participate in distributed brain networks, and flexibly modify these interactions, in order to carry out complex behavioral functions.

Tropospheric photochemistry, particularly the formation of ozone (O3), depends not only on pollutant emissions, but also on meteorological conditions. In this study a 3-D chemical transport model CAMx was employed to investigate the O3 formation and its response to emission reductions under three distinctively different meteorological conditions ("Cold Surge", "O3-North" and "O3-South") in the Mexico City Metropolitan Area during the MCMA-2003 field measurement campaign. The O3 formation characteristics and sensitivity to emissions changes were found to be weakly dependent on the meteorological conditions. The evolution of O3 formation and sensitivity were also examined along the photochemical plume transport pathway. The midday O3 production was found to undergo a rapid increase in a narrow range of chemical aging, while plumes in the downwind were characterized with low and constant O3 production, and plumes along their transport pathway were featured by a combination of the two. The O3 formation was more VOC sensitive near the source area, but as the plume became chemically aged, O3 formation became progressively VOC insensitive and more NOx sensitive.

This article reviews ultrasound segmentation methods, in a broad sense, focusing on techniques developed for medical B-mode ultrasound images. First, we present a review of articles by clinical application to highlight the approaches that have been investigated and degree of validation that has been done in different clinical domains. Then, we present a classification of methodology in terms of use of prior information. We conclude by selecting 10 papers which have presented original ideas that have demonstrated particular clinical usefulness or potential specific to the ultrasound segmentation problem.