ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / Prognostic technology uses a series of algorithms, combined forms a prognostic-based inference engine (PBIE) for the identification of deterministic behavior embedded in completely normal appearing telemetry from fully functional equipment. The algorithms used to define normal behavior in the PBIE from which deterministic behavior is identified can be adapted to quantify normal spacecraft telemetry behavior while in orbit about a moon or planet or during interplanetary travel. Time-series analog engineering data (telemetry) from orbiting satellites and interplanetary spacecraft are defined by harmonic and non-harmonic influences, which shape it behavior. Spectrum analysis can be used to understand and quantify the fundamental behavior of spacecraft analog telemetry and relate the behavior's frequency and phase to its time-series behavior through Fourier analysis.

ITC/USA 2009 Conference Proceedings / The Forty-Fifth Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2009 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Prognostic technology uses a series of algorithms, combined forms a prognostic-based inference engine (PBIE) for the identification of deterministic behavior embedded in completely normal appearing telemetry from fully functional equipment. The algorithms used to define normal behavior in the PBIE from which deterministic behavior is identified can be adapted to quantify normal spacecraft telemetry behavior while in orbit about a moon or planet or during interplanetary travel. Time-series analog engineering data (telemetry) from orbiting satellites and interplanetary spacecraft are defined by harmonic and non-harmonic influences which shape it behavior. Spectrum analysis can be used to understand and quantify the fundamental behavior of spacecraft analog telemetry and relate the behavior's frequency and phase to its time-series behavior through Fourier analysis.

At the time of writing, stress and stress related disease have become the most common reasons for absence in the workplace in Sweden. The purpose of the work presented here is to identify and notify people managing unhealthy levels of stress. Since symptoms of mental stress manifest through functions of the Sympathetic Nervous System (SNS), they are best measured through monitoring of SNS changes and phenomena. In this study, changes in the sympathetic control of heart rate were recorded and analyzed using heart rate variability analysis and a simple runner’s heart rate sensor connected to a smartphone. Mental stress data was collected through stressful video gaming. This was compared to data from non-stressful activities, physical activity and extremely stressful activities such as public speaking events. By using the period between heartbeats and selecting features from the frequency domain, a simple machine learning algorithm could differentiate between the types of data and thus could effectively recognize mental stress. The study resulted in a collection of 100 data points, an algorithm to extract features and an application to continuously collect and classify sequences of heart periods. It also revealed an interesting relationship in the data between different subjects. The fact that continuous stress monitoring can be achieved using minimally intrusive sensors is the greatest benefit of these results, especially when connsidering its potential value in the identification and prevention of stress related disease.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Prognostic technology uses a series of algorithms, combined forms a prognostic-based inference engine (PBIE) for the identification of deterministic behavior embedded in completely normal appearing telemetry from fully functional equipment. The algorithms used to define normal behavior in the PBIE from which deterministic behavior is identified can be adapted to quantify normal spacecraft telemetry behavior while in orbit about a moon or planet or during interplanetary travel. Time-series analog engineering data (telemetry) from orbiting satellites and interplanetary spacecraft are defined by harmonic and non-harmonic influences, which shape it behavior. Spectrum analysis can be used to understand and quantify the fundamental behavior of spacecraft analog telemetry and relate the behavior's frequency and phase to its time-series behavior through Fourier analysis.

Ultrasound is a commonly used imaging modality in diagnosis and pre-operative assessment of breast masses. However, radiologists often find it very difficult to correctly size masses using conventional ultrasound images. Consequently, there exists a strong need for more accurate sizing tools to avoid either the removal of an over-estimated amount of tissue or a second surgical procedure to remove margins involved by tumour not removed in the primary operation. In this thesis, we propose a new method of processing the backscattered ultrasound signals from breast tissue (based on the Fourier spectral analysis) to better estimate the degree of echogenicity and generate parametric images where the visibility of breast mass boundaries is improved (SPV parametric image). Moreover, an algorithm is proposed to recover some anatomical structures (particularly, Cooper’s ligaments) which are shadowed during the image acquisition process (LWSPV parametric image). The information from both algorithms is combined to generate a final SPV+LWSPV parametric image. A 20-case pilot study was conducted on clinical data, which showed that the SPV+LWSPV parametric image added useful information to the B-mode image for clinical assessment in 85% of the cases (increase in diagnostic confidence in at least one boundary). Moreover, in 35% of the cases, the SPV+LWSPV parametric image provided a better definition of the entire boundary. Note that the radiologist knew the final diagnosis from histopathology. In addition, the SPV+LWSPV method has the advantage that it uses the I/Q data from a standard ultrasound equipment without the need for additional hardware. On the basis of these facts, we believe there to be a case for further investigation of the SPV+LWSPV imaging as a useful clinical tool in the pre-operative assessment of breast mass boundaries.

We studied Heart Rate Variability (HRV) evolution during therapeutic hypothermia in newborns with hypoxic ischemic encephalopathy (HIE) using spectral analysis. We hypothesized that HRV measures are predictive of neurological outcome in babies with HIE. Non-stationarity in the data causes inaccurate quantification of the spectral power. A modification was proposed to power spectral analysis approach to mitigate the effect of non-stationarity. The modified and the standard approaches were applied to cardiac beat-to-beat intervals of newborns receiving hypothermia treatment. The performance of the approaches in distinguishing the RRi dynamics of two groups of newborns was assessed using area under the receiver operating characteristic (ROC) curve. Our results showed that the modified spectral analysis distinguished the two groups of neonates better than the standard approach. These results may be useful in identifying the deteriorating physiology of the infants receiving hypothermia treatment early in time and strategize alternate interventions for them.

Acoustically, teleost swimbladders have been considered resonant underwater bubbles. Contrary results indicating that bladders are tuned less sharply than such a bubble have been explained by damping of surrounding fish tissue. Recent findings in toadfish and weakfish, however, suggest that the bladder is a highly damped structure and that the frequency of the fish sounds is deternlined as a forced response to sonic muscle movement rather than by resonance of the bladder. In this study I examined acoustics and material properties of swimbladders in Tilapia (an auditory generalist) and the channel catfish (an auditory specialist). The swimbladder was struck with a piezoelectric impact hammer. Amplitude and timing characteristics of bladder sound and displacement were compared for strikes of different amplitudes. Most of the first cycle of sound occurs during swimbladder compression, indicating that the bladder rapidly contracts and expands as force increases during the strike. Harder hits are shorter in duration generate a similar displacement duration with an increasing number of shorter cycles and a 12-15 dB increase in sound amplitude. The frequency spectrum is broad, and the dominant frequency is driven by the strike and not the natural frequency of the bladder. The displacement waveform varies between species catfish exhibit a greater structural stiffness and lower amplitude movement and higher sound amplitude for an equivalent hammer strike. Material properties (peak load, stress, strain, Young's modulus), fiber direction (catfish only), and structural stiffiless of bladders exhibit various patterns suggesting that the bladder walls are not uniform structures. Additionally thickness varies regionally. Notably Young's modulus in both species is similar despite large difference in stress and strain. The modulus of catfish bladder increased 1600-fold when dried. Finally the bladder of both species had a high water content averaging about 70%. These data suggest that viscous damping caused by water in the bladder wall is a major factor responsible for acoustic properties of the teleost swimbladder.

Abstract A computer program has been written to simulate the conditions of the early uni- verse and to test a new idea in the mechanism of structure formation observed in our universe today. The model utilises Newtonian hydrodynamic equations includ- ing gravitational and electromagnetic forces in two spatial dimensions. It is proposed that augmenting gravitational forces with plasma forces will complement the prob- lematic Big Bang theory of structure formation which relies on gravity alone. Two sets of initial conditions are tested and the products of the simulation are analysed in a statistical way using power spectra and the two-point correlation function. Differ- ences in the initial conditions were not seen to produce significantly different results. The results show that the Hubble expansion term significantly reduces power in the gravity models but plasma forces can retain power better than similar gravitation- only models. Initial velocity perturbations significantly modify the power spectrum gradient in the higher modes. Some power spectra displayed a definite bend in gra- dient at a scale which is verified by galaxy survey observations. Plasma forces also appear to cluster matter on smaller scales more efficiently than gravity alone. Thus, this simulation lays a foundation for a more detailed and realistic model that may be compared with real matter distribution observations.

Le centre coloré azote-lacune du diamant, appelé centre NV, est comparable à un atome piégé à l’état solide. Ses propriétés de spin, conservées à température ambiante, permettent la détection de résonances magnétiques par voie purement optique. Le travail décrit dans cette thèse est centré sur l’utilisation d’ensembles de centres NV pour répondre à des problématiques à la fois scientifiques et industrielles. Nous avons réalisé un microscope de photoluminescence permettant d’exploiter les propriétés d’une couche nanométrique de centres NV. Les images obtenues ont une résolution spatiale de 500 nm et les fluctuations du signal sont limitées par le bruit de photons. En soumettant les centres NV à un signal hyperfréquence connu, nous pouvons reconstituer la cartographie à l’échelle microscopique des trois composantes d’espace d’un champ magnétique : par exemple, celui produit par un conducteur parcouru par un courant. La sensibilité associée à une surface d’intégration de 1 µm² de la couche de centres NV est de l’ordre du microtesla par racine de hertz. Notre dispositif d’imagerie permet également d’analyser le spectre d’un signal hyperfréquence. En soumettant les centres NV à un gradient de champ magnétique connu, l’information spectrale est transformée en information spatiale. Des résultats préliminaires montrent l’analyse simultanée d’une bande de fréquences de 700 MHz associée à une résolution de 7 MHz et à un taux de rafraîchissement de 4 ms. Ces travaux illustrent les perspectives prometteuses du centre NV du diamant, notamment pour le contrôle de circuits électroniques et l’analyse en temps réel de spectres hyperfréquences pris dans leur ensemble. / The nitrogen-vacancy color center of diamond, called NV center, is an atom like system trapped in a solid lattice. Its spin properties, kept at room temperature, allow the detection of magnetic resonances by purely optical means. The work described in this thesis is focused on the use of NV centers’ ensembles targeting both scientific and industrial issues. We realized a photoluminescence microscope that exploits the properties of a nanoscale layer of NV centers. The spatial resolution of the resulting image is around 500 nm and the fluctuations of the signal is limited by the shot-noise. When the NV centers are submitted to a microwave signal witch frequency is known, the cartography of the three spatial components of the magnetic field, the one produced by a conductor carrying a current for example, can be determined at the microscopic scale. The sensitivity associated to an integration surface on the NV center layer of 1 µm² is in the order of the microtesla per square root of hertz. Our imaging device also leads to the spectral analysis of a microwave signal. When the NV centers are submitted to a known magnetic field gradient, the spectral information is transformed into spatial information. Preliminary results show the simultaneous analysis of a 700 MHz frequency band associated to a resolution of 7 MHz and a refresh rate of 4 ms. These works illustrate promising perspectives for the NV center of diamond, especially for the control of electronic circuits and the real time analysis of a whole microwave spectrum.

Esta tese é composta de três artigos. O primeiro artigo aplica a metodologia proposta por Chari, Kehoe e McGrattan (2003) para decompor as flutuações da indústria brasileira, usualmente medidas por meio da aplicação de filtros mecânicos. Sugere-se que os ciclos encontrados pela utilização do filtro Hodrick Prescott (ou qualquer filtro band pass) englobam oscilações econômicas cuja origem pode ser deslocamentos tanto da demanda quanto da oferta. Em particular, as simulações a partir de dados reais indicam que a maior parte dos ciclos brasileiros têm origem na oferta. Este resultado sugere que a calibração da política monetária a partir da noção usual de “hiato do produto" é potencialmente falha. De fato, estimativas da curva IS a partir dos componentes cíclicos associados à oferta e à demanda mostra que o impacto negativo de uma elevação de juros é relativamente maior sobre a oferta. De certa forma, portanto, há um viés inflacionário no uso da política monetária. Uma estimativa da Curva de Philips com o componente cíclico associado às mudanças de demanda revela coeficiente positivo maior do que o observado em modelos estimados com a medida usual de “hiato do produto". O segundo artigo compara a performance de filtros band pass com a do filtro Hodrick Prescott na determinação dos ciclos do produto brasileiro. Conclui-se, com base em inspeção do desempenho na amostra de dados disponível e em simulações de Monte Carlo, que o filtro Hodrick Prescott é inferior às alternativas consideradas quando o objetivo é extrair os ciclos em “tempo real". Essa conclusão é válida para dois modelos estatísticos alternativos de descrição do PIB: (i) supondo que a variável é I(0) em torno de uma tendência linear com “quebras" e (ii) supondo que a variável é I(1). Há também robustez com relação ao parâmetro de comparação do desempenho dos filtros. O terceiro artigo obtém: (i) uma série do PIB trimestral dessazonalizado perfeitamente compatível com as variações anuais, desde 1980, corrigindo um problema de ajustamento existente na série disponível eletronicamente; (ii) uma série confiável desde 1970, a partir de técnicas de desagregação temporal utilizando indicadores; (iii) uma série trimestral desde 1947 que, provavelmente, preserva uma parcela razoável dos componentes do PIB normalmente associados aos ciclos econômicos e; (iv) uma série alternativa que, provavelmente, incorpora uma parte dos componentes irregulares do período que vai de 1956 a 1969. / The first paper applies the methodology proposed by Chari, Kehoe and McGrattan (2003) to analyze cyclical fluctuations of the Brazilian industry, usually obtained by means of mechanical filters. The results suggest that filter-obtained cycles – using the Hodrick Prescott filter or a band pass filter – include components originated from supply and demand disturbances. Particularly, the simulations indicate that most Brazilian cycles are due to supply movements. This result leads to the conclusion that calibrating monetary policy based on a filter-obtained “output-gap" is potentially flawed. Indeed, IS curve estimations using supply-driven and demand-driven cyclical components show that the impact of monetary policy is more significant in the former than the latter. Thus, it would seem that there is an inflation bias in current monetary policy practice. The paper shows also that a Phillips Curve estimated from demand-driven cyclical components reveals a higher coefficient than one obtained by the usual regressions. The second paper compares the performance of band pass filters with the Hodrick Prescott filter in terms of their ability to extract the cycles of Brazilian GDP in “real time". Using actual and artificial data, the simulations indicate that the Hodrick Prescott filter is inferior. This conclusion holds for two alternative models to describe the GDP dynamics: (i) supposing the series is I(0) around a deterministic trend with a few structural breaks and (ii) supposing the series is I(1). The results are also robust with respect to more than one benchmark chosen to evaluate the performance of the filters. The third paper obtains: (i) a seasonally adjusted quarterly GDP series for the period 1980 to 2002, that is perfectly compatible with the annual National Accounts real variations, correcting a step problem present in the electronically available series; (ii) a reliable series going back to 1970, using temporal disaggregation methods with indicators; (iii) a series going back to 1947 that, most likely, preserves a reasonable amount of the cyclical components of the GDP and (iv) a series going back to 1956 that is likely to include part of the irregular components.