Scattering

It is shown that the Fraunhofer diffraction pattern of a tilted aperture screen can be interpreted as a ' monocular view of the Ewald sphere. Two of those patterns recorded at opposite tilting angles are used to give a stereoscopic impression of the Ewald sphere. Experimental results are shown, and the approximations involved are discussed.

The realistic performance of a multi-input multi-output (MIMO) communication system depends strongly on the spatial correlation properties introduced by clustering in the propagation environment. Simulating realistic correlated channels is essential to predict the performance of real MIMO systems. Since the modeling method of the correlated channels suggested by the Third Generation Partnership Project (3GPP) channel model can result in considerable implementation complexity for large networks, this paper presents a computationally efficient method to approximately calculate the spatial correlation matrix for channel models such as the 3GPP channel model, which are based on clusters of scatterers. This proposed approximation method is on the basis of using the Taylor series expansion to the steering vectors for uniform linear arrays (ULAs) and a moderate angle spread of the cluster. The approximation method is evaluated in terms of the mean square error (MSE) of the approximated correlation matrix, and by the cumulative distribution function (CDF) of the mutual information of the MIMO channel. This shows that the proposed approximation method is close for angle spread of the cluster within 10 , with high efficiency and low complexity.

Background: Double Charge Exchange (DCE) nuclear reactions have recently attracted much interest as tools to provide experimentally driven information about the Nuclear Matrix Elements of interest in the context of neutrino-less double beta decay. In this framework a good description of the reaction mechanism and a complete knowledge of the initial and final state interactions is mandatory. Presently, not enough is known about the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for future DCE studies. Among these, 20 Ne + 76 Ge DCE reaction is particularly relevant due to its connection with 76 Ge double beta decay. Purpose: Characterization of the initial state interaction for the 20 Ne + 76 Ge reactions at 306 MeV bombarding energy: determination of the optical potential and exploration of the role of the couplings between elastic channel and inelastic transitions to the first low-lying excited states. Methods: Determination of the experimental elastic and inelastic scattering cross section angular distributions. Comparison of the theoretical predictions adopting different models of optical potentials with the experimental data. Evaluation of the coupling effect through the comparison of the Distorted Wave Born Approximation calculations with the Coupled Channels ones. Results: Optical Models fail in the description of the elastic angular distribution above the grazing angle (∼ 9.4 •). A correction in the geometry to effectively account for deformation of the involved nuclear systems improves the agreement up to about 14 •. Coupled channels effects are crucial to obtain a good agreement at large angles in the elastic scattering cross section. Conclusions: The analysis of elastic and inelastic scattering data turned out to be a powerful tool to explore the initial and final state interaction in heavy ion nuclear reactions also at high transferred momenta.

System-on-chip (SoC) architectures are called to be the platform for an ever increasing number of interactive applications. One of the most time- consuming tasks is to define communication interfaces between the different components through a number of scattered heterogeneous processing nodes. That is not only a complex task, but also very specific to a certain implementation, which may limit the flexibility of the system, and makes the solutions difficult to reuse. In this paper, we describe how the distributed systems paradigm can be extended to provide a unified abstraction for both hardware and software components. Moreover, based on that abstraction, we define a low-overhead system-wide communication architecture that offers communication transparency between all kinds of components. Since the architecture is highly compatible with standard distributed object software systems, it also allows seamless interaction with any other kind of external network.

Angular Domain Imaging (ADI) is a high resolution, ballistic imaging method that utilizes the angular spectrum of photons to filter multiply-scattered photons which have a wide distribution of angles from ballistic and quasi-ballistic photons which exit a scattering medium with a small distribution of angles around their original trajectory. Such spatial gating has been previously accomplished using a scanning array of collimating holes micromachined into a silicon wafer section. We now extend that work to include using a wide-beam, full-field, converging lens and pinhole aperture system to capture images in a single exposure. We have developed an analysis of resolution and sensitivity trade-offs of such a system using Fourier optics theory to show that the system resolution is primarily governed by collimation ability at larger aperture sizes and by spatiofrequency (Fourier space-gated) filtering at smaller aperture sizes. It is found that maximum sensitivity is achieved when spatiofrequency resolution and collimation resolution are equal. Planar, high contrast, phantom test objects are observed in 5 cm thick media with effective scattered to ballistic photon ratios >1.25×10 7 :1 using a wide-beam, full-field lens and aperture system. Comparisons are made between ballistic imaging with the lens and aperture system and with the scanning silicon micromachined collimating array. Monte-Carlo simulations with angular tracking validate the experimental results.

Vector formalism for stimulated Brillouin scattering amplification in birefringent fibers is used to model the fiber as an equivalent, pseudo-linear, polarization-dependent gain medium. Implications on slow and fast light setups are discussed.

Tarantula is an aggressive floating point machine targeted at technical, scientific and bioinformatics workloads, originally planned as a follow-on candidate to the EV8 processor [6, 5]. Tarantula adds to the EV8 core a vector unit capable of 32 double-precision flops per cycle. The vector unit fetches data directly from a 16 MByte second level cache with a peak bandwidth of sixty four 64-bit values per cycle. The whole chip is backed by a memory controller capable of delivering over 64 GBytes/s of raw bandwidth. Tarantula extends the Alpha ISA with new vector instructions that operate on new architectural state. Salient features of the architecture and implementation are: (1) it fully integrates into a virtual-memory cache-coherent system without changes to its coherency protocol, (2) provides high bandwidth for non-unit stride memory accesses, (3) supports gather/scatter instructions efficiently, (4) fully integrates with the EV8 core with a narrow, streamlined interface, rather than acting as a co-processor, (5) can achieve a peak of 104 operations per cycle, and (6) achieves excellent "real-computation" per transistor and per watt ratios. Our detailed simulations show that Tarantula achieves an average speedup of 5X over EV8, out of a peak speedup in terms of flops of 8X. Furthermore, performance on gather/scatter intensive benchmarks such as Radix Sort is also remarkable: a speedup of almost 3X over EV8 and 15 sustained operations per cycle. Several benchmarks exceed 20 operations per cycle.

Spotlighting is one illumination field where the application of light emitting diodes (LED) creates many advantages. Commonly, the system for spot lights consists of a LED light engine and collimating secondary optics. Through angular or spatial separated emitted light from the source and imaging optical elements, a non uniform far field appears with colored rings, dots or patterns. Many feasible combinations result in very different spatial color distributions. Several combinations of three multi-chip light sources and secondary optical elements like reflectors and TIR lenses with additional facets or scattering elements were analyzed mainly regarding the color uniformity. They are assessed by the merit function U sl which was derived from human factor experiments and describes the color uniformity based on the visual perception of humans. Furthermore, the optical systems are compared concerning efficiency, peak candela and aspect ratio. Both types of optics differ in the relation between the color uniformity level and other properties. A plain reflector with a slightly color mixing light source performs adequate. The results for the TIR lenses indicate that they need additional elements for good color mixing or blended light source. The most convenient system depends on the requirements of the application.

This paper reports experimental measurements of the radiation characteristics of green algae used for carbon dioxide fixation via photosynthesis. The generated biomass can be used to produce not only biofuels but also feed for animal and food supplements for human consumptions. Particular attention was paid to three widely used species namely Botryococcus braunii, Chlorella sp., and Chlorococcum littorale. Their extinction and absorption coefficients were obtained from normal-normal and normal-hemispherical transmittance measurements over the spectral range from 400 to 800 nm. Moreover, a polar nephelometer was used to measure the scattering phase function of the microorganisms at 632.8 nm. It was observed that for all strains, scattering dominates over absorption. The magnitudes of the extinction and scattering crosssection are functions of the size, shape, and chlorophyll content of each strain in a nontrivial manner. Absorption peaks at 435, 475, and 676 nm corresponding to chlorophyll a and chlorophyll b. The results can be used for scaling and optimization of CO 2 fixation in ponds or photobioreactors as well as in the development of controlled ecological life support systems.

The detection of concealed weapons at a distance is a critical security issue that has been a great challenge for different imaging approaches. In this paper we discuss the use of ultrasonics in a novel way to probe for metallic and non-metallic materials under clothing. Conventional ultrasonics has problems penetrating clothing and produces false positives from specular reflections. Our approach is to use ultrasonics to create a localized zone where nonlinear interactions generate a lower frequency acoustic wave that is able to penetrate clothing better than direct ultrasonics. The generation of a probing beam for concealed weapons is described in this brief summary showing comparisons of the physical models with the experimental data. An imaging scan of concealed improvised weapons seized by officials at corrections institutes is presented to highlight the value of this approach.

Neste trabalho, compósitos de elastômero termoplástico de poliuretano (TPU) foram preparados com diferentes teores de argila (0, 1, 3 e 10% m/m). A argila Cloisite 30B (C30B) foi incorporada na matriz de TPU via processamento por fusão (extrusora de dupla rosca; compósitos TPU-E) e polimerização em massa (compósitos TPU-S). O método de síntese foi a polimerização em duas etapas do poliol poliéster (massa molar de 2000 g mol-1) e do di-isocianato de 4,4' difenil metano (MDI) com 1,4-butanodiol como extensor de cadeia. A dispersão da argila e seu efeito sobre as propriedades mecânicas dos compósitos foram investigadas. A caracterização dos compósitos de TPU com argila foi realizada através da microscopia eletrônica de varredura (MEV) e da difração de raios-X (DRX). As propriedades mecânicas foram avaliadas através da resistência à tração e ao rasgamento. O TPU-E com 3% de argila apresentou os melhores resultados com aumento nos valores de tensão e no alongamento na ruptura (28% e 35%, respectivamente) e na energia (88%), comparado ao TPU-E (amostra sem argila). Palavras-chave: TPU, argila, microscopia eletrônica de varredura, difração de raios-X, propriedades mecânicas. Morphology and Mechanical Properties of TPU Nanoclay Composites In this study thermoplastic polyurethane (TPU) composites were obtained with different nanoclay contents (0, 1, 3 for all cases and 10 wt% in some cases). The nanoclay Cloisite 30B (C30B) was dispersed in the TPU matrix by melt processing (twin-screw extruder; TPU-E composites) and during bulk polymerization (TPU-S composites). The synthesis method involved the two-step bulk polymerization of polyesterpolyol (molecular weight 2.000 g mol-1) and diphenylmethanediisocyanate (MDI) with 1,4-butanediol as the chain extender. The dispersion state of the nanoclay particles and its effect on the mechanical properties of the composites was investigated. The characterization of TPU/nanoclay composites was carried out by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanical characterization was carried out by means of tensile and tear strengths test. The TPU-E 3 wt% composite showed the best improvement with increases in stress and strain at break (28% and 35%, respectively) and energy (88%), compared to the TPU-E (sample without nanoclay).

In this work, we pave the route towards the engineering of strong and spectrally sharp Fano resonances in plasmonic nanostructures and derive analytical formulas for their line shape as a function of their electromagnetic response. Contrary to the original work of Fano, the formalism proposed here includes losses in the materials composing the system. As a result, a more general formula is obtained for the response of the system and general conclusions for the determination of the resonance parameters are drawn, in particular on its width and asymmetry. Using a surface integral simulation technique for electromagnetic scattering on three-dimensional individual and periodic nanostructures, we numerically validate our model for structures that are currently under extensive investigation in the plasmonic and metamaterial communities. The insights into the physical comprehension of Fano resonances gained this way will be of great interest for the design of plasmonic sensing platforms and metamaterials.

Phase velocity of a surface acoustic wave (SAW) varies when the electric field associated with the wave interacts with a conductive material located above the propagation plane. In this paper, we propose a general method to approximate the scattering matrix when the conductive structure has a specific geometry. This structure has reflective properties of SAW. As an example, we considered a previously reported SAW-MEMS microaccelerometer which mainly consists of a slotted beam. By applying this method, we obtained the relationship between acceleration and the reflection and transmission coefficients. The dynamic of the slotted beam was studied using the finite element method (FEM). It was observed that relatively small variations in the size of the microstructure could cause significant changes in the reflection and transmission coefficients. We also show that the slotted beam acts as an acoustic wave bandpass filter, and its response is similar to that of reflective gratings, but with linear phase.

The group theoretical treatment of bound and scattering state problems is extended to include band structure. We show that one can realize Hamiltonians with periodic potentials as dynamical symmetries, where representation theory provides analytic solutions, or which can be treated with more general spectrum generating algebraic methods. We find dynamical symmetries for which we derive the transfer matrices and dispersion relations. Both compact and non-compact groups are found to play a role.

The image quality of electro-optical sensors in the (lower-altitude marine) atmosphere is limited by aerosols, which cause contrast reduction due to transmission losses and impact on the thermal signature of objects by scattering solar radiation. The Advanced Navy Aerosol Model (ANAM) aims at providing a quantitative estimate of the aerosol effects on the basis of standard meteorological parameters such as wind speed and relative humidity. For application in coastal regions, the ANAM includes non-marine aerosols that are governed by an ill-defined tuning parameter: the air mass parameter (AMP). The present paper proposes a new parameterization for assessing the effect of these non-marine particles on the propagation. The new parameterization utilizes the Ångström coefficient, which can be experimentally obtained with a sun photometer, and introduces new types of aerosols in ANAM. The new parameterization was tested against experimental validation data acquired at Porquerolles Island at the French Riviera. The limited test data suggested that the new parameterization is only partially efficient in capturing the aerosol signature of the coastal environment. Nevertheless, the new Ångström coefficient algorithm avoids using the ill-defined AMP, and may thus be useful to the ANAM community.

Starting with the exact solution for the scattering of a plane P wave by a homogeneous spherical inclusion, various types of approximate solutions are developed and discussed. The standard Rayleigh and Mie approximations are extended to the case of inclusions having arbitrary contrasts in material properties. For the low-contrast case, solutions are developed which are valid over a wide frequency range. Several aspects of these solutions are discussed, including the importance of near-field terms and the relative strength of the scattered P and S fields. The various types of approximate solutions are compared with each other and with the exact solution by calculating and displaying their normalized scattering cross-sections.

In this review, we discuss the use of inorganic nanoparticles, mainly zinc oxide (ZnO) and titanium dioxide (TiO 2 ), for sunscreen applications considering their intrinsic physical properties and the Mie theory. These properties cause, from one side, attenuation of the ultraviolet light by absorption and scattering (dependent on a particle size), which is the purpose sunscreens are designed for, and formation of free radicals (i.e., phototoxicity) during this process-from the other. Particle penetration into skin is also an important issue addressed in this review due to possible adverse effects associated with interaction between nanoparticles and skin living cells.

Afrstract-A method is described for enlcrdating the dynamical (frequency-dependent) properties of varions microstrip discontinuities such as unsymmetrical crossings, T junctions, right-angle bends, impedance steps, and filter elements. The method is applied Ito an unsymmetrical T junction with three different linewidths. Using a wavegnide model with frequency-dependent parameters, a field matching method proposed by Kiihn is employed to compute tlhe scattering matrix of the strictures. The elements of the scattering mntrix calculated in this way differ from those derived from static methods by a bigher frequency dependence, especially for frequencies near tlhe cutoff frequencies of the higher order modes on the microstrip lines. The theoretical results are compared with measurements, and theory and experiment are fonnd to correspond closely.

We study planar waves in a circulating, draining fluid flow, which: (i) exhibit an analogue of the Aharonov–Bohm (AB) effect in Quantum Mechanics; (ii) obey a Klein–Gordon equation on an ‘effective spacetime’ which resembles the Kerr spacetime of General Relativity; and (iii) may be observed in the laboratory using gravity waves in a shallow basin. We describe a modified AB effect which depends on two dimensionless parameters, associated with the circulation α and draining β rates; we call this the ‘αβ effect’. We show that the αβ effect is inherently asymmetric even in the low-frequency limit, and that it leads to novel interference patterns which carry the signature of both rotation and absorption.

The detection of concealed weapons at a distance is a critical security issue that has been a great challenge for different imaging approaches. In this paper we discuss the use of ultrasonics in a novel way to probe for metallic and non-metallic materials under clothing. ...

Scattering of an arbitrary elastic wave incident upon a spherically symmetric inclusion is considered and solutions are developed in terms of the spherical vector system of Petrashen, which produces results in terms of displacements rather than displacement potentials and in a form suitable for accurate numerical computations. Analytical expressions for canonical scattering coefficients are obtained for both the cases of incident P waves and incident S waves. Calculations of energy flux in the scattered waves lead to elastic optical theorems for both P and S waves, which relate the scattering cross sections to the amplitude of the scattered fields in the forward direction. The properties of the solutions for a homogeneous elastic sphere, a sphere filled by fluid, and a spherical cavity are illustrated with scattering cross sections that demonstrate important differences between these types of obstacles. A general result is that the frequency dependence of the scattering is defined by the wavelength of the scattered wave rather than the wavelength of the incident wave. This is consistent with the finding that the intensity of the P~S scattering is generally much stronger than the S-~P scattering. When averaged over all scattering angles, the mean intensity of the P -, S converted waves is 2 Vp 2 / V 4 times the mean intensity of the S ~P converted waves, and this ratio is independent of frequency. The exact solutions reduce to simple and easily used expressions in the case of the low frequency (Rayleigh) approximation and the low contrast (Rayleigh-Born) approximation. The case of energy absorbing inclusions can also be obtained by assigning complex values to the elastic parameters, which leads to the result that an increase in attenuation within the inclusion causes an increased scattering cross section with a marked preference for scattered S waves. The complete generality of the results is demonstrated by showing waves scattered by the earth's core in the time domain, an example of high-frequency scattering that reveals a very complex relationship between geometrical arrivals and diffracted waves.

The recently introduced random walker segmentation algorithm of has been shown to have desirable theoretical properties and to perform well on a wide variety of images in practice. However, this algorithm requires user-specified labels and produces a segmentation where each segment is connected to a labeled pixel. We show that incorporation of a nonparametric probability density model allows for an extended random walkers algorithm that can locate disconnected objects and does not require user-specified labels. Finally, we show that this formulation leads to a deep connection with the popular graph cuts method of .

The optical properties of human cranial bones were measured in the wavelength range 800-2000 nm. The measurements were carried out using the commercially available spectrophotometer with an integrating sphere. The inverse addingdoubling method was used to determine the absorption and reduced scattering coefficients from the measurements.

Resonances, which are also described as autoionizing or quasi-bound states, play an important role in the scattering of atoms and ions with electrons. The current article is an overview of the main methods, including a recently-proposed one, that are used to find and analyze resonances.

When the mechanisms of fading channels were first modeled in the 1950s and 1960s, the ideas were primarily applied to over-the-horizon communications covering a wide range of frequency bands. The 3-30 MHz high-frequency (HF) band is used for ionospheric communications, and the 300 MHz-3 GHz ultra-high-frequency (UHF) and 3-30 GHz super-high-frequency (SHF) bands are used for tropospheric scatter. Although the fading effects in a mobile radio system are somewhat different than those in ionospheric and tropospheric channels, the early models are still quite useful to help characterize fading effects in mobile digital communication systems. This tutorial addresses Rayleigh fading primarily in the UHF band. That affects mobile systems such as cellular and personal communication systems (PCS). Part I of the tutorial itemizes the fundamental fading manifestations and types of degradation

because it gave each of their organizations the opportunity and means to upgrade and improve upon existing instrumentation and equipment necessary to support their research reactor's operations as well as their research initiatives. In addition, INIE funding had a direct result in the increasing usage by faculty and researchers at each organization thereby strengthening their respective educational and research goals. The decision to implement the Innovation in Nuclear Infrastructure and Engineering Program (INIE) was an important first step towards ensuring that the United States preserves its worldwide leadership role in the field of nuclear science and engineering. Prior to INIE, university nuclear science and engineering programs were waning, undergraduate student enrollment was down, university research reactors were being shut down, while others faced the real possibility of closure. For too long, cutting edge research in the areas of nuclear medicine, neutron scattering, radiochemistry, and advanced materials was undervalued and therefore underfunded. The INIE program corrected this lapse in focus and direction and started the process of drawing a new blueprint with positive goals and objectives that supports existing as well the next generation of educators, students and researchers.

Many imaging systems deal with phase measurements using coherent radiation in order to illuminate objects. The reflected scattered return carries information on physical and geometrical properties of illuminated objects. It can be information on shape, deformation, movement and structure of the object's surface. We propose a novel phase unwrap filtering for noisy holographic data. Based on the window size adaptive local polynomial approximation it allows dramatically reduce level of noise and in the same time preserve phase variation features. Simulation shows that the technique enables an advanced accuracy for phase reconstruction from wrapped noisy observations.

In this paper, general mixing formulas are derived for discrete scatterers immersed in a host medium. The inclusion particles are assumed to be ellipsoidal. The electric field inside the scatterers is determined by quasi-static analysis, assuming the diameter of the inclusion particles to be much smaller than wavelength. The results are applicable to general multiphase mixtures, and the scattering ellipsoids of the different phases can have different sizes and arbitrary ellipticity distribution and axis orientation, i.e., the mixture may be isotropic or anisotropic. The resulting mixing formula is nonlinear and is especially suitable for iterative solutions. The formula contains a quantity called the apparent permittivity, and with different choices of this quantity, the result leads to the generalized Lorentz-Lorenz formula, the generalized Polder-van Santen formula, and the generalized coherent potential-quasicrystalline approximation formula. Finally, the results are applied to calculating the complex effective permittivity of snow and sea ice.

The theoretical/experimental work done in the area of digital phase-locked loops (DPLL) from 1960 to 1980 is surveyed. The survey is motivated by the fact that microprocessor technology is advancing rapidly to the extent that sophisticated and flexible signal processing algorithms for communications and control can be realized in the digital domain. It is anticipated that the use of this signal processing technology will continue to expand rapidly in the development of advanced communications and tracking receivers, for example, digital modems.

Point defect thermodynamics at the solidevapor equilibrium and point defect diffusion is reviewed in cadmium telluride with an emphasis on recent experimental findings. Principles and benefit of respective experimental methods studying defect structure both in situ in hightemperature thermodynamic equilibrium and frozen at room or lower temperatures are outlined. The comprehensive theory based on quasichemical formalism is presented in a form, which can be easily applied to binary semiconductors. The effect of Fermi level to the point defect concentration and diffusion is demonstrated at length. We argue that in spite of increasing knowledge the understanding of defect structure in CdTe is not satisfactory yet. New experiments on well defined samples with precisely known thermodynamic history and minimized density of unintentional impurities are requested.

Most high-speed multiple-access networks on the market, or those currently under design, operate in a limited geographical environment and are devoted either to data-only or voice-only transmission. However, challenges issued by the marketplace require the full integration of voice, data, and video in a real-time environment. This paper proposes a metropolitan area network that covers a campus environment and truly integrates voice, data, and video under a single transmission medium. Furthermore, the transmission is achieved through a single media-access schema. This paper also presents marketing issues, network requirements, and technology constraints. The proposed mediaaccess schema is also being considered by the IEEE 802.6 MAN Committee for Standardization.

Humanitarian demining aims for a total clearance of all types of landmines from infected areas and infrastructures as efficiently and as safely and as rapidly as possible while keeping cost to minimum. It requires that each individual mine in an area to be located, uncovered and removed or destroyed. The focus is to make these areas economically viable and usable by the people for different activities and to allow people to use their land without fear. The targets of mine detection and sensing technologies are to achieve a high probability of detection rate while maintaining low probability of false alarm. But, the probability of false alarm rate is directly proportional to the time and cost of demining by a large factor. Careful study of the limitations of any detection and sensing capabilities with regard to the location, weather, environment, and soil composition is critical along with the required technical operation and maintenance skills, while keeping in mind that not all high-tech solutions may be workable in different soil and environmental conditions. Wide variety of mine detection and sensor technologies has been developed while others are in varying stages of development. But it is clear that no single available technology has the capability to detect and recognize a variety of mines under all situations. Also most of these methods and techniques are very slow, have low accuracy, complex and large in size, andor expensive and suffer from a high false alarm rate. Due to this, some efforts are even trying combinations of various new technologies, and some are combining their new techniques with ordinary metal detectors and other sensors to increase the sensitivity of their particular methods. This paper presents the landmine problems, the problems facing humanitarian demining, priorities and an evaluation of mine detection techniques and technologies along with their new development potential in the context of humanitarian demining.

Visual appearance of objects comes from the interpretation by the human visual system of a light signal issued from the objects. Describing or predicting appearance is therefore a question of light and requires notions about light propagation and measurement. In this paper, we introduce basic laws of optics, the science of light, and radiometry, the science of light measurement, in the context of colored surfaces. We address light spectrum and illuminants, polarization, notions of reflectance and transmittance based on radiometric definitions, gloss, absorption, scattering, fluorescence and models for light reflection and transmission by flat and rough surfaces, by slabs of nonscattering media and diffusing layers. Throughout the paper, we present the most current methods to assess the different physical quantities by measurement.

this topic of research, and guiding me through to its completion. I also thank my parents who have supported me in every way throughout my education. And a very special thanks to Anne who has supported and encouraged me at all times, but especially during the most trying ones. Sean Cullen greatly aided me in performing the numerical analysis of Chapter V. Roxana Moreland performed the superior technical typing seen within these pages.

This paper presents several methods based on signal strength and wave scattering models for tracking a user. The received-signal level method is first used in combination with maximum likelihood (ML) estimation and triangulation to obtain an estimate of the location of the mobile. Due to nonline-of-sight conditions and multipath propagation environments, this estimate lacks acceptable accuracy for demanding services, as the numerical results reveal. The 3-D wave scattering multipath channel model of Aulin is employed, together with the recursive nonlinear Bayesian estimation algorithms to obtain improved location estimates with high accuracy. Several Bayesian estimation algorithms are considered, such as the extended Kalman filter (EKF), the particle filter (PF), and the unscented PF (UPF). These algorithms cope with nonlinearities in order to estimate mobile location and velocity. Since the EKF is very sensitive to the initial state, we propose the use of the ML estimate as the initial state of the EKF. In contrast to the EKF tracking approach, the PF and UPF approaches do not rely on linearized motion models, measurement relations, and Gaussian assumptions. Numerical results are presented to evaluate the performance of the proposed algorithms when the measurement data do not correspond to the ones generated by the model. This shows the robustness of the algorithm based on modeling inaccuracies.

This paper presents a general strategy for the electrical performance and Signal Integrity assessment of electrically long multi-chip links. A black-box time-domain macromodel is first derived from tabulated frequency responses in scattering form. This model is structured as a combination of ideal delay terms with frequency-dependent rational coefficients. A new identification scheme is presented, based on an initial blind delay estimation process, followed by a refinement loop based on an iterative Delayed Vector Fitting (DVF) process. Two alternative passivity enforcement schemes based on local perturbations are then presented. The result is an accurate and guaranteed passive delay-based macromodel, which is synthesized as a SPICEcompatible netlist for channel analysis. The proposed procedure enables safe and reliable circuit-based transient simulations of complex multi-chip links, including nonlinear drivers and receivers. The performance of the proposed flow is demonstrated on a large number of channel benchmarks.

This paper reports on the use of digitally-enhanced print-based interfaces to support both individual and social information gap tasks. The interactive social nature of language learning can be supported through social scaffolding designed into instruction. Our current work focuses on a well-established information gap task referred to as cloze used under three conditions: individual, dyadic, and whole class. This project investigates enhancing cloze with a patented Cluster Pattern Interface (CLUSPI ® ) . CLUSPI allows digitally encoded information to be embedded in a layer of clustered graphical objects on printed documents and permits paper materials to link with language tools through a point-and-click interface.

Raman spectroscopy has evolved into an important fast, direct and nondestructive technique in pharmaceutical analysis. Usually, the focus in this field is mainly on the active ingredients and not on the excipients present in the drugs. A collection of Raman spectra of widely used pharmaceutical excipients is presented in this article, which can serve as a reference for the interpretation of Raman spectra during drug analysis (including classical qualitative and quantitative pharmaceutical analysis, counterfeit tracing and process analytical technology (PAT) applications). The 43 analyzed excipients can be classified into seven categories: mono-and disaccharides (dextrose, lactitol, maltitol, lactose and sucrose), polysaccharides (microcrystalline cellulose, methylcellulose (MC), carboxymethylcellulose (CMC), hydroxypropyl cellulose (HPC), hydroxypropyl methylcellulose (HPMC), wheat starch, maltodextrin, primojel, tragacanth and pectin), polyalcohols (propylene glycol, erythritol, xylitol, mannitol and sorbitol), carboxylic acids and salts (alginic acid, glycine, magnesium stearate, sodium acetate and sodium benzoate), esters (arachis oil, lubritab, dibutyl sebacate, triacetin, Eudragit E100 and Eudragit RL100), inorganic compounds (calcium phosphate, talc, anatase and rutile (TiO 2 ), calcium carbonate, magnesium carbonate, sodium bicarbonate and calcium sulfate) and some unclassified products [gelatin, macrogol 4000 (polyethylene glycol (PEG), polyvinyl pyrrolidone and sodium lauryl sulfate].