Coherent detection together with multilevel modulation formats has the potential to significantly increase the capacity of existing optical communication systems at no extra cost in signal bandwidth. However, these modulation formats are more susceptible to the impact of different noise sources and distortions as the distance between its constellation points in the complex plane reduces with the modulation index. In this context, digital signal processing (DSP) plays a key role as it allows compensating for the impairments occurring during signal generation, transmission and/or detection relaxing the complexity of the overall system. The transition towards pluggable optical transceivers, offers flexibility for network design/upgrade but sets strict requirements on the power consumption of the DSP thus limiting its complexity. The DSP module complexity however, scales with the modulation order and, in this scenario, low complex yet high performance DSP algorithms are highly desired. In this thesis, we mainly focus on the impact of laser phase noise arising from the transmitter and local oscillator (LO) lasers in coherent optical communication systems employing high order modulation formats. In these systems, the phase noise of the transmitting and LO lasers translate into phase noise in the received constellation impeding the proper recovery of the transmitted data. In order to increase the system phase noise tolerance, we firstly explore the possibility of re-arranging the constellation points in a circularly shaped mQAM (C-mQAM) constellation shape to exploit its inherent phase noise tolerance. Different low-complex carrier phase recovery (CPR) schemes applicable to these constellations are proposed along with a discussion on its performance and implementation complexity. Secondly, the design guidelines of high performance and low complex CPR schemes for conventional square mQAM constellations are presented. We identify the inherent limitation of the state-of-the-art blind phase search (BPS) carrier phase recovery algorithm which hinders its achievable performance and implementation complexity and present a low complex solution to overcome it. The design guidelines of multi-stage CPR schemes for high order modulation formats, where the BPS algorithm is employed at any of the stages, are also provided and discussed. Finally, the interplay between the received dispersed signal and the LO phase noise is analytically investigated to characterize the origin of the equalization enhanced phase noise phenomena. / <p>QC 20170516</p> / EU project ICONE, gr. #608099

Die Grundlage vieler zukünftiger Flüssigszintillator-Neutrinoexperimente (SNO+, Daya Bay, LENA) ist das Lösungsmittel Lineare-Alkyl-Benzene (LAB, C6H5CnH2n+1, n = 10 - 13). Zusammen mit dem weit verbreiteten Szintillator 2,5-Diphenyloxazole (PPO) ist es ein farb- und geruchsloses Detektormaterial mit hohem Flammpunkt. Im Vergleich zu toluol- oder xylolbasierten Szintillatoren ist LAB+PPO preiswert und nicht gesundheitsschädlich. Die Eigenschaften von LAB machen es ebenfalls interessant für die Anwendung an nELBE, die Neutronenfugzeitanlage im Helmholtz-Zentrum Dresden - Rossendorf. Ein neuer Ansatz zur Bestimmung der Lichtausbeute im niederenergetischen Bereich (bis 2 MeV) wird vorgestellt. Kombiniert wurden Messungen mit (quasi) monoenergetischen Gammastrahlungs-Prüfstrahlern und einem in dieser Arbeit aufgebauten Compton-Spektrometer. Letzteres ermöglicht die Bestimmung der Lichtausbeute bis zu 5 keVee. Der Birks-Parameter wurde für eine Lösung von LAB + 3 g/l PPO sowie für den Flüssigszintillator NE-213 bestimmt. Die relative Lichtausbeute in Bezug auf letzteren konnte mit diesen Messmethoden ebenfalls ermittelt werden. Zur spektralen Analyse des Lumineszenzlichtes wurden Messungen an Fluoreszenz- und UV/VIS- Spektrometern durchgeführt. Die Pulsformdiskriminationsfähigkeit auf LAB basierenden Szintillatoren wurde während eines Flugzeitexperiments in einem gemischten n-gamma-Feld eines Cf(252)-Prüfstrahlers ermittelt. Dabei kamen unterschiedliche Algorithmen der semi-analogen und digitalen Pulsformdiskrimination zum Einsatz. / Linear alkyl benzene (LAB, C6H5CnH2n+1, n = 10 - 13) is the proposed solvent for the SNO+, the Daya Bay Neutrino and LENA experiment. In solution with the commonly used scintillator PPO it is a colourless, odourless and cheap liquid scintillator with a high fash point and low health hazard compared to toluene based ones. The properties of LAB make this scintillator interesting also for nELBE, the neutron time-of-fight facility at Helmholtz-Zentrum Dresden - Rossendorf. A new approach to measure the light yield in the low-energy range using a combination of quasi-monoenergetic photon sources and a Compton-spectrometer is described. The latter allows the measurement of the light yield down to 5 keVee (electron equivalent). The Birks- Parameter was determined for a homemade solution (LAB + 3 g/l PPO) and for NE-213. The light yield (relative to this standard scintillator) was confrmed by measurements using a fuorescence spectrometer. The ability of pulse-shape-discrimination in a mixed n-gamma- field of a Cf(252) source was tested using different digital and semi-analogue techniques.

Muitas pesquisas tem sido feitas em processamento digital de sinais (PDS) na tentativa de se avaliar o sinal de fala para diagnosticar doenças da laringe. Medidas acústicas têm sido propostas de forma a avaliar indiretamente o trato glotal por meio do sinal de voz coletado através de microfone convencional. Para isso, o modelo paramétrico Liljencrants-Fant (LF) foi desenvolvido para representar o sinal glotal em condições normais e patológicas. Tais parâmetros apresentam vantagens sobre medidas acústicas por possuírem características fisiológicas reais das pregas vocais. Assim, podendo ser empregados para identificação de doenças da laringe. Além da estimação dos parâmetros LF, no domínio do tempo (parâmetros T), a forma de onda da derivativa glotal também pôde ser quantificada através dos parâmetros identificados na literatura por parâmetros R (Rd, Ra, Rk e Rg), parâmetros quocientes Q (SQ, OQ, CQ, AQ e NAQ), parâmetros B1 e B2 que são as extensões de bandas do pulso derivativo LF, e o parâmetro ece, que relaciona os parâmetros &#946 e Ta. Os parâmetros B1 e B2 e ece apesar de serem propostos na literatura, não são encontrados resultados diferentes a essas duas medidas. Os resultados mostraram que os parâmetros B não foram confiáveis na discriminação entre as vozes, por outro lado, o parâmetro ece mostrou-se ser opção na discriminação entre as vozes normais, nódulo e Reinke. O objetivo deste trabalho é direcionar a atenção sobre o sinal glotal, estimando-o automaticamente mediante técnicas de PDS aplicadas ao sinal de fala, visando extrair parâmetros que identifiquem as condições normais e patológicas da laringe. Por fim foram propostos os parâmetros TRp e TRs, visando dissociar os efeitos de primeira ordem dos de ordem superior na fase de retorno do pulso glotal com a finalidade de estimar a real não-linearidade do sub-sistema glotal, retratando as condições normais e patológicas da laringe. Por fim foram propostos os parâmetros TRp e TRs, visando dissociar os efeitos de primeira ordem dos de ordem superior na fase de retorno do pulso glotal com a finalidade de estimar a real não-linearidade do sub-sistema glotal, retratando as condições fisiológicas do movimento das pregas vocais. Com um nível de confiança de 95%, o parâmetro de primeira ordem (TRp) é efetivo na discriminação do Edema de Reinke, porém mostrou-se ineficaz na detecção do nódulo. Em relação ao parâmetro de ordem superior, conclui-se que o TRs é um excelente detetor de vozes patológicas (nódulo e Edema de Reinke), porém não é capaz de discriminar as patologias. / Many researches has been conducted in digital signal processing (DSP) atempting to evaluate the physiological conditions of larynx. Acoustical parameters have been proposed to evaluate the glotal tract from voice signal. One technique proposed is the Liljencrants-Fant model (LF) developed to represent normal and pathologic conditions of the larynx. Those parameters compare favourably as far as real physiologic characteristic of vocal folds is concerned. So, a primary use of the model is the larynx pathologic identification. Beyond LF parameters estimation, (T parameters in the time domain), the waveform of glotal pulse derivative also can be quantified through, R parameters (Rd, Ra, Rk and Rg), quocient parameters (SQ, OQ, CQ, AQ and NAQ), B parameters (B1 and B2) that are band extension of the LF glotal pulse derivative and the ece parameter that in fact, is a relationship between &#946 and Ta. Although proposed in the literature, no results are found, related to B and ece parameters. Our founds show that B parameters do not present good results in voice discrimination, however, ece parameter seems to be good option to discriminate normal voice, nodulo and Reinke edema. The main purpose of this work is to estimate the glotal signal from the voice signal using DSP techniques in order to obtain parameters that identifies the physiological larynx condition. In order to estimate the shape of return phase of glotal pulse, twoparameters have been proposed in this work. The first one evaluates the pulse (TRp, in other words, the first order component of the return phase. The second is responsible to evaluate superior orders components of the return phase (TRs), i.e, the non-linear component of the glotal pulse. With 95% of confidence level, TRp is effective in Reinke edema discrimination however it is inefficient for nodule e dection. By the other hand, the TRs parameter works well to detect pathologic voice however is unable to discriminated them.

"Non-invasive remote physiological monitoring of soldiers on the battlefield has the potential to provide fast, accurate status assessments that are key to improving the survivability of critical injuries. The development of WPI’s wearable wireless pulse oximeter, designed for field-based applications, has allowed for the optimization of important hardware features such as physical size and power management. However, software-based digital signal processing (DSP) methods are still required to perform physiological assessments. This research evaluated DSP methods that were capable of providing arterial oxygen saturation (SpO2), heart rate (HR), heart rate variability (HRV), and respiration rate (RR) measurements derived from data acquired using a single optical sensor. In vivo experiments were conducted to evaluate the accuracies of the processing methods across ranges of physiological conditions. Of the algorithms assessed, 13 SpO2 methods, 1 HR method, 6 HRV indices, and 4 RR methods were identified that provided clinically acceptable measurement accuracies and could potentially be employed in a wearable pulse oximeter."

<p>Докторска тема описује и анализира развој алата за профилисање и естимацију потрошње енергије наменских апликација. Апликације о којима је реч се развијају за вишејезгарну хетерогену платформу пројектовану са нагласком на ниској потрошњи енергије. Истраживање се односи на изналажење могућности прецизне процене количине енергије коју конзумира наменска DSP аппликација приликом обраде улазног сигнала. Резултат истраживања је израда прецизаног модела потрошње енергије који омогућује директну спрегу између програмског решења које се развија и количине енергије потребне за његово извршавање. Основни циљ истраживања је развој енергетски ефикасних програмских решења. Модел представљен у овом раду остварује зависност између утрошка енергије и програмског решења на инструкционом нивоу. Тестирањем модела кроз реалне апликације је остварена прецизна процена утрошене енергије.</p> / <p>Doktorska tema opisuje i analizira razvoj alata za profilisanje i estimaciju potrošnje energije namenskih aplikacija. Aplikacije o kojima je reč se razvijaju za višejezgarnu heterogenu platformu projektovanu sa naglaskom na niskoj potrošnji energije. Istraživanje se odnosi na iznalaženje mogućnosti precizne procene količine energije koju konzumira namenska DSP applikacija prilikom obrade ulaznog signala. Rezultat istraživanja je izrada precizanog modela potrošnje energije koji omogućuje direktnu spregu između programskog rešenja koje se razvija i količine energije potrebne za njegovo izvršavanje. Osnovni cilj istraživanja je razvoj energetski efikasnih programskih rešenja. Model predstavljen u ovom radu ostvaruje zavisnost između utroška energije i programskog rešenja na instrukcionom nivou. Testiranjem modela kroz realne aplikacije je ostvarena precizna procena utrošene energije.</p> / <p>PhD thesis describes and analyzes an approach to the development of the<br />tool for energy consumption profiling and estimation of embedded<br />applications aimed for multi-core heterogeneous platform designed with an<br />emphasis on low power consumption. The main purpose of this study was to<br />enable prediction of the amount of energy consumed by embedded DSP<br />application, when processing the input signal. The primary goal was to obtain<br />a precise model of energy consumption that will establish a direct link<br />between program solutions and the amount of energy required for its<br />execution, in order to develop energy-efficient software solutions. The model<br />presented in this paper achieves link between energy consumption and<br />program solutions at instructional level. The solution was tested against a<br />real applications and it has been established that prediction of consumed<br />energy have a high degree of accuracy.</p>

<p>A channel change in digital television is usually conducted at a reference frame, which are sent at certain intervals. A higher compression ratio could however be obtained by sending reference frames at arbitrary long intervals. This would on the other hand increase the average channel change time for the end user. This thesis investigates various approaches for reducing the average channel change time while using arbitrary long intervals between reference frames, and presents an implementation and evaluation of one of these methods, called Baydec.</p><p>The approach of Baydec for solving the channel switch problem is to statistically estimate what the original image looked like, starting with an incoming P-frame and estimate an image between the original and current image. Baydec gathers statistical data from typical video sequences and calculates expected likelihood for estimation. Further on it uses the Simulated Annealing search method to maximise the likelihood function.</p><p>This method is more general than the requirements of this thesis. It is not only applicable to channel switches between video streams, but can also be used for random access in general. Baydec could also be used if an I-frame is dropped in a video stream.</p><p>However, Baydec has so far shown only theoretical result, but very small visual improvements. Baydec produces images with better PSNR than without the method in some cases, but the visual impression is not better than for the motion compensated residual images. Some examples of future work to improve Baydec is also presented.</p>

No description available.

Las técnicas de estimación de canal y de adaptación de la transmisión a las condiciones del entorno son temas de interés actual al estudiar la aplicación de técnicas de diversidad en transmisión en la tercera y cuarta generación de sistemas inalámbricos. En esta tesis se realiza un análisis del impacto del error de estimación de canal y la correlación en sistemas OFDM con diversidad en transmisión basados en codificación espacio-tiempo por bloques (STBC), se proponen técnicas de estimación de canal para estos sistemas y se propone una técnica de adaptación de la transmisión mediante la selección de código espacio-tiempo. En primer lugar, una técnica sencilla de mínimos cuadrados en el dominio de la frecuencia permite la estimación de canal en sistemas con dos antenas y constelaciones complejas, y con tres o cuatro antenas y constelaciones reales o complejas, utilizando STBCs ortogonales como bloques de entrenamiento. En segundo lugar, una representación 'sobre-completa' permite hacer una estimación diferencial de canal para un sistema con tres antenas transmisoras mediante la selección a partir de un banco de posibles estimadores, basándose en la redundancia provista por la matriz de transmisión no cuadrada del código ortogonal esporádico de tasa 3/4 para tres antenas transmisoras.En el contexto de sistemas con adaptación del transmisor, la técnica propuesta de diversidad por selección adaptativa de código espacio-tiempo se basa en el estado instantáneo del vector de canal y en un conjunto de niveles umbrales hallados fuera de línea en función del período de realimentación. Los resultados indican que esta técnica proporciona buenas prestaciones en canales correlados e incorrelados. Su aplicación a sistemas OFDM ha sido estudiada, superando a técnicas de selección de antena y a otras técnicas de transmisión adaptativa. / Channel estimation and adaptive transmission techniques are areas of increasing interest these days when considering transmit diversity systems for the 3G and 4G wireless communication systems. In this thesis an analysis of the channel estimation and channel correlation impact on transmit diversity OFDM systems based on space-time block coding (STBC) is presented, two channel estimation techniques are outlined and an adaptive space-time code selection technique is proposed. First, a simple frequency domain least square technique allows channel estimation for two transmitter systems with complex constellation, and three or four transmitter systems with real or complex constellation, using orthogonal STBCs as training blocks. Second, an 'overcomplete' representation allows a di.erential channel estimation for three transmitter systems through the instantaneous selection from a bank of estimators, based on the redundacy provided by the non-square transmission matrix of the sporadic 3/4-rate STBC for three transmitters.In the context of transmit adaptive systems, the proposed adaptive space-time code selection technique is based on both the instantaneous channel vector state and a set of predetermined threshold levels found o.-line as a function of the feedback period. Analytical and simulation results show that the proposed technique has a good performance in the presence of correlated and uncorrelated channels. Its application to OFDM systems has been considered, outperforming classical antenna selection techniques and other closed-loop adaptive transmission techniques.

1.1 Objectius de la tesi.En els últims anys el control del parell i de la velocitat del motor d'inducció ha estat llargament estudiat. Un cop s'ha considerat que les prestacions dinàmiques assolibles eren ja suficientment satisfactòries, els diferents investigadors han reorientat els seus esforços cap a altres enfocs relacionats, ja no únicament amb el MI estrictament parlant, sinó amb tot el sistema que constitueix l'accionament amb si mateix.L'objectiu principal d'aquesta tesi és posar en evidència, l'existència d'unes idealitzacions i limitacions dels controls tradicionals de parell i velocitat del motor d'inducció (bàsicament del Control Vectorial i del DTC), així com a proposar mètodes i algorismes alternatius que superin a les mateixes.1.2 Estructura i contingutEl Capítol 1 conté una introducció al treball.El segon capítol Modelització del motor d'inducció, presenta les principals tècniques i equacions, que porten a descriure d'una forma dinàmica al MI.El tercer capítol, Control de parell i velocitat del MI, es descriuen els Control Vectorial i el Control Directe de Parell (DTC), ja que són els més estudiats en la literatura.El quart capítol, Estudi dels bucles de corrent, tracta més en profunditat una de les limitacions que presenta el Control Vectorial, l'estudi de les interaccions que hi ha entre els dos llaços de regulació de les intensitats de l'estator (la seva component directa i en quadratura).En el cinquè capítol, OSVPWM (Optimized Space Vector PWM), es presenta un estudi detallat dels diferents mètodes d'ondulació (DC/AC) que existeixen. D'entre tots aquests, s'estudia amb molt més deteniment el Space Vector PWM (SVPWM), aportant un nou algorisme d'implementació del mateix (optimitzat per DSP's), així com posant en evidència la negativa influència dels temps morts sobre el mateix.El sisè capítol presenta l'ODTC (Optimized Direct Torque Control), com a resum de tots els capítols anteriors.1.3 Aportacions d'aquesta tesi.En la modelització matemàtica del Motor d'Inducció, s'ha arribat a la formulació d'una equació genèrica, que engloba totes les possibles referències, i totes les definicions d'intensitats magnetitzants.En l'estudi del DTC s'ha presentat una nova taula de commutació, que permet disminuir l'excessiu arrissat de parell que presenta la taula de commutació tradicional.En l'estudi del SVPWM s'ha presentat una nova formulació molt més apta per a la seva implementació en DSP (Digital Signal Processor). Igualment, s'ha posat en evidència la important influència dels temps morts dels interruptors, en la THD (Tasa de Distorsió Harmònica) de l'ona de tensió de sortida de l'ondulador proposant un algorisme de compensació (OSVPWM).S'ha proposat un nou algorisme de control del parell del MI, incorporant les prestacions del DTC en règim transitori (ràpida resposta del parell), i les prestacions del Control Vectorial en règim permanent (petit arrissat de parell), amb la incorporació de l'OSVPWM com a estratègia de modulació.Finalment destacar, l'aportació d'un equip experimental basat en DSP, de disseny molt versàtil i robust, i que incorpora tota una sèrie d'eines de desenvolupament que el fan molt útil per a l'experimentació de noves lleis de control, referides principalment al motor d'inducció, però que també s'ha demostrat eficient alhora de treballar amb altres plantes com és el cas dels SAI's (Sistemes d'Alimentació Ininterrompuda).1.4 Futures línies de recerca.Seguir treballant en l'estudi del OSVPM, però en el cas de la sobremodulació, és a dir, quan la tensió de consigna superi o surti fora dels rangs d'aplicabilitat del mateix.Amb l'obtenció de l'equació que ens permet estimar l'arrissat màxim de parell, associat al conjunt motor-ondulador, estudiar el disseny de controladors per histèresi de banda d'histèresi variable (funció de l'estat de l'accionament).Finalment destacar, que amb el constant augment de la potència de càlcul dels DSP, les possibilitats de noves lleis de control del MI ("fuzzy logic" i "passivity control") són cada dia més possibles, i per tant s'han convertit en una línia de treball molt interessant.

Modern embedded processors with dedicated address generation unit support memory accesses using indirect addressing mode with auto-increment and auto-decrement. The auto-increment/decrement mode, if properly utilized, can save address arithmetic instructions, reduce static and dynamic footprint of the program and speed up the execution as well. We propose an optimization framework for embedded processors based on the auto-increment and decrement addressing modes for address registers. Existing work on this class of optimizations focuses on using an access graph and finding the maximum weight path cover to find an optimized stack variables layout. We take this further by using coalescing, addressing mode selection and offset registers to find further opportunities for reducing the number of load-address instructions required. We also propose an algorithm for building the layout with considerations for memory accesses across basic blocks, because existing work mainly considers intra-basic-block information. We then use the available offset registers to try to further reduce the number of address arithmetic instructions after layout assignment.