La arquitectura de las redes de transporte actuales está basada en la tecnología de transporte SDH (Synchronous Digital Hierarchy). Las redes SDH se han diseñado y están optimizadas básicamente para el transporte del tráfico de voz. Actualmente, se está experimentando un crecimiento exponencial del volumen de tráfico de datos. Este crecimiento se debe a que el protocolo IP se está consolidando como capa de integración para servicios múltiples, algunos de ellos con requerimientos de Calidad de Servicio (QoS) y también a la introducción de tecnología de acceso de alta velocidad. Las características estadísticas del tráfico de datos son diferentes respecto a las del tráfico telefónico. De hecho, el tráfico IP se caracteriza no solo por su asimetría sino por su naturaleza dinámica, ya que presenta fluctuaciones o picos difíciles de predecir a priori.Como consecuencia, ha surgido la necesidad de emigrar desde las actuales redes hacia una estructura más flexible y dinámica, optimizada para el transporte de tráfico de datos.La evolución de las actuales redes de transporte incluye trasladar todas las funcionalidades de SDH (conmutación, monitorización de la calidad de la señal, protección frente a fallos) a nivel óptico. El resultado consistirá en una red de transporte óptica (Optical Transport Network, OTN) basada en tecnología DWDM, con Optical Cross Connects (OXC) para encaminar canales ópticos de forma permanente o conmutada (Automatic Switched Optical Network, ASON).Uno de los principales problemas a solucionar por las operadoras de red es la eficiente gestión de la capacidad disponible, y así evitar por un lado la necesidad de sobredimensionar la red de transporte y por el otro optimizar la utilización de los recursos mediante la definición de estrategias de ingeniería de tráfico.La introducción de las redes de transporte a conmutación automática (ASON), capaces de proporcionar conexiones ópticas bajo demanda, es considerada como la solución de red que puede proporcionar el rápido y flexible aprovisionamiento de ancho de banda. Tal funcionalidad, posible gracias a la definición de un plano de control basado en el paradigma GMPLS, puede ser usada para gestionar de manera dinámica los recursos disponibles, tanto a nivel SDH como a nivel óptico, respondiendo de forma eficiente a las fluctuaciones del tráfico generado por la red cliente. Sin embargo, el problema que surge es el diseño de un mecanismo para disparar automáticamente las peticiones de establecimiento de circuitos SDH/canales ópticos conmutados.En este sentido, la primera contribución de esta Tesis es el diseño de un mecanismo de disparo de peticiones de circuitos SDH/canales ópticos basado en la monitorización y predicción del tráfico de la red cliente (IP). Además, el mecanismo diseñado incluye la definición de políticas de ingeniería de tráfico para la optimización de la utilización del elevado ancho de banda proporcionado por las conexiones ópticas. Concretamente, el mecanismo diseñado se caracteriza por la interoperabilidad entre la capa cliente y la capa de transporte.La Tesis incluye también una contribución sobre el diseño de una metodología para el dimensionado de la redes ASON, basada en la caracterización del tráfico de llegadas de peticiones de establecimiento de conexiones, mediante su valor medio y el factor de peakedness.Por otro lado, la optimización de los recursos disponibles es muy crítica cuando se produce un fallo en la infraestructura de red debido a la necesidad de encontrar rutas alternativas para el tráfico afectado. Debido al gran volumen de tráfico a transportar, un fallo en la infraestructura de red puede tener graves consecuencias económicas. Por ejemplo, un corte de una única fibra óptica produce el fallo de todas las longitudes de onda que transporta; de esta manera la pérdida de cada longitud de onda operante a 2.5 Gbps o 10 Gbps puede resultar en el corte de un enorme número de conexiones en curso. Por lo tanto, a mayor capacidad, mayor es la importancia de la rapidez y rendimiento de los mecanismos de protección y recuperación.Las estrategias de protección frente a fallos deben ser simples, minimizar las pérdidas de tráfico y deben utilizar eficientemente los recursos disponibles.La recién estandardizada tecnología para redes de entornos metropolitanos, Resilient Packet Ring (RPR) se caracteriza por mecanismos de protección optimizados para minimizar el tiempo de recuperación en caso de fallos. Además, tales mecanismos no requieren la asignación a priori de recursos de red a utilizar solamente en caso de fallos.Por lo que respecta a los mecanismos de recuperación, se puede optar por una estrategia de recuperación en una sola capa (single layer recovery) o alternativamente por una estrategia de recuperación en múltiples capas (multi-layer recovery), donde en la recuperación intervienen diferentes capas de la estructura de red. El esquema de recuperación multi-capas más fácil de implementar es el consistente en ejecutar los mecanismos de protección/recuperación de los distintos niveles de manera paralela e independiente. Esta estrategia no es, sin embargo, la más eficiente. La interoperabilidad entre los mecanismos de protección de las diferentes capas permite reaccionar más rápidamente a los fallos que se pueden producir.La segunda contribución de esta Tesis es el diseño de una política de coordinación entre los mecanismos de protección proporcionados por RPR y los mecanismos de protección definidos por la capa óptica. Concretamente, la estrategia diseñada se basa en la interoperabilidad entre la capa RPR y la capa de transporte (OTN) para redes de entornos metropolitanos. La estrategia diseñada permite, además, la optimización de los recursos de red. / The main objective of the traffic engineering (TE) strategies is the efficient mapping of the actual traffic onto the available network resources. Legacy Time Division Multiplexing-based networking architecture was basically designed to transport symmetric voice traffic. However, the volume of data traffic is increasing at explosive rate and already dominates the voice traffic. This is due to a progressive migration of many applications and services over the Internet Protocol (IP) and also to a deeper and deeper introduction of high-speed access technologies. Also there is the convergence towards the IP of real-time applications (i.e. multimedia applications) which have very strict QoS requirements. The statistical characteristics of the data traffic are rather different from those of telephone traffic. Specifically, IP traffic is highly dynamic showing predictable and unpredictable traffic surges/peaks. Such surges are caused by unexpected events such as user' behaviours, weather conditions, accidents, fault, etc. This can cause significant fluctuations of the aggregated data traffic to be carried by the transport networks. The current SONET/SDH transport networks (but also the incoming Optical Transport Networks) tend to be static, which means that connections (SONET/SDH circuits and light paths) are provided manually through the Network Management System. The manual configuration is time consuming, which means that weeks or even months are needed to provide high bandwidth connections.The highly dynamic IP traffic pattern does not match with the static provisioning of capacity of the optical transport networks, leading to non-optimal utilization of the resources (i.e. network congestion or under-utilization of resources).Thus, the problem that arises for Network Operators is how to efficiently manage the network resources in the transport network to efficiently respond to the changes in the traffic demands reaching, in such a way, traffic engineering objectives. The introduction of the Automatic Switched Optical Networks (ASON), which is able to provide dynamically switched connections on demand, is recognized as the enabling solution to meet the requirement of fast and flexible end-to-end bandwidth provisioning. The automatic set up and tear down of optical connections can be used for the dynamic management of the transport network resources to track significant variations in the volume of the network client traffic. In such a context, a mechanism that triggers demands to set up/tear down light paths as a function of the variation of the client traffic to be transported is required. The design of a multi-layer traffic engineering (MTE) strategy for IP/MPLS over ASON/GMPLS networks to face with the dynamic traffic demands is the first contribution of this Ph.D. Thesis. It has to be underlined that the policies for the set up of the light paths are out of the scope of this work. In fact, it is assumed that the set up/tear down of the switched connections is in charge of the ASON control plane, namely the GMPLS-based routing and signalling protocols.As a second contribution, it is presented a practical approach for ASON networks dimensioning purposes based on the approximate characterization of the traffic arrival process, through its mean and the peakedness factor. On the other hand, the optimization of the utilization of network resources is very critical when failures occur in the network as a consequence of the need of rerouting the affected traffic. The increase of the capacity and number of wavelengths that can be multiplexed onto the same fibre, each one carrying 2.5 or 10 Gbps client signals, implies that outages of the network infrastructure can have serious economical and social consequences. Network recovery/resilience, i.e., the capability of the networks to efficiently recover from failures, has become of vital importance. Thus, optical transport networks need to be very robust to face failures. The protection mechanisms should be designed basically with the aim to be simple, to minimize the traffic losses and to optimize the utilization of the network resources.Survivability strategies in current transport networks are based on the pre-allocation of network resources to be used only to switch (route) the affected traffic in case of failures. In legacy multi-layer networks, each layer (e.g. IP, SDH) has its own protection mechanism built in, independent from the other layers. Network recovery basically relies on the SONET/SDH network layer. Indeed, different mechanisms, based on the protection approach, have been proposed that allow fast recovery within the target of 50 ms. Nevertheless, SONET/SDH protection is mainly limited to ring topologies and it is not able to distinguish between different priorities of traffic and it has not vision of higher layer failures.The emerging packet-based Resilient Packet Ring (RPR) technology for metropolitan networks provides powerful protection mechanisms that minimize the time needed to restore the traffic without the pre-allocation of resources.To face to failures, the resilience single-layer strategy (a single layer has the responsibility for the recovery) is very simple from the implementation point of view. However it may not be able to efficiently recover the network from all kind of failures that can occur. Therefore, multi-layer resilience (various network layers can participate to the recovery actions) provides better performance not only in terms of protection but also in terms of resources optimization. Multi-layer resilience strategies require coordinating the recovery mechanisms provided by each layer. In such a context, another contribution of this Ph.D. Thesis is the design and evaluation of a multi-layer resilience mechanism to be used in the IP over RPR over intelligent optical transport network for metropolitan environment to efficiently face with a wide range of network outages, while optimizing the utilization of the network resources. Its novelty relies on the interworking required between the RPR and the optical transport layer. Finally, the fourth contribution of the Thesis deals with the optimization of the bandwidth utlization of the RPR rings taking benefits from the automatic switching of optical connections capabilities of the underlying ASON/GMPLS networks.

A permanent magnet synchronous motor is traditionally controlled from measured values of the angular velocity and position of the rotor. However, there is a wish from SAAB Avitronics to investigate the possibility of estimating this angular velocity and position from the current measurements. The rotating rotor will affect the currents in the motor’s stator depending on the rotor’s angular velocity, and the observer estimates the angular velocity and angular position from this effect. There are several methods proposed in the article database IEEE Xplore to observe this angular velocity and angular position. The methods of observation chosen for study in this thesis are the extended Kalman filter and a phase locked loop algorithm based on the back electro motive force augmented by an injection method at low velocities. The extended Kalman filter was also programmed to be run on a digital signal processor in SAAB Avitronics’ developing hardware. The extended Kalman filter performs well in simulations and shows promise in hardware implementation. The algorithm for hardware implementation suffers from poor resolution in calculations involving the covariance matrices of the Kalman filter due to the use of 16-bit integers, yielding an observer that only functions in certain conditions. As simulations with 32-bit integer algorithm performs well it is likely that a 32- bit implementation of the extended Kalman filter would perform well on a motor, making sensorless control possible in a wide range of operations.

This master’s thesis work was performed at Volvo Powertrain in Köping, Sweden, which manufactures gearboxes and integrated transmission systems for heavy vehicles. The thesis is a continuation of a previous master’s thesis performed at the Köping factory in 2009. After manufacturing and assembly, each gearbox is manually validated to ensure the gearbox quality and functionality. When validating the gearbox gears, the operator shifts the gearbox in a predefined manner and listens for irregularities. If an error sound is heard the operator must then locate the source of error. With numerous of cog wheels rotating at the same time this task requires extensive knowledge and experience of the operator. The main objective is to develop an automatic diagnostic system for detection of cog errors and assist the operator in the process of locating the faulty component. The work consists of two parts. In the first part the automatic diagnostic system is developed and a database of gearbox recordings is stored. The amounts of logged non-faulty gearboxes are significantly much larger (50) than the logged faulty gearboxes (1). Therefore, when determining thresholds needed for the diagnosis, the data obtained from the non-faulty gearboxes are used. Two statistical methods are presented to extract the thresholds. The first method uses an extremevalue distribution and the other method a Gaussian distribution. When validated, both methods did successfully detect on cog faults. In the second part an investigation is made of how shaft imbalance can be detected and implemented in the developed system. Volvo Powertrain continually follows-up all faults found at the validation station to ensure the quality of their work and eliminate the sources of error. During system testing one logged gearbox was found faulty. The automatic diagnostic system did successfully detect and locate the faulty component which later also was confirmed when the gearbox was dismounted. With only one detected error it is difficult to conclude the system performance and further testing is required. However, during the testing no false detections were made.

The nematode Caenorhabditis elegans is a model organism for understanding sensory molecules of multicellular organisms. Ovulating hermaphrodites produce putative pheromone(s) that cause male attraction. Because pheromones are produced in such small quantities, adult conditioned-media from large-scale synchronous culture is necessary to analyze these pheromones. Current protocols for culture synchronization have volume constraints that limit large-scale synchronous cultures and current methodology for adult conditioned-media production is impractical. Modification of Tangential Flow Filtration (TFF) systems was investigated for use as a method to increase the volume limits of bleach egg harvest for C. elegans culture synchronization. Also, an adult retention device built within the culture vessel was investigated to optimize the environment for aseptic conditioned-media production from dense large-scale C. elegans cultures. During this investigation, we have shown that synchronous C. elegans cultures for adult conditioned-media production can be grown at scales larger than reported before, with potential for further scale up. Our growth methodologies have also yielded denser cultures than previously achieved at large scales. Since rapid bleach harvesting appears to be the bottleneck for large-scale production of synchronous C. elegans cultures, our approach of using modified TFF systems with mesh to retain C. elegans eggs increased the amount of eggs that could be bleach harvested at one time. Using this method we have been able to achieve up to 5x103 synchronous C. elegans per mL at a 50L scale. Since scale-up of TFF is straightforward, our results suggest that the technique reported here can easily be applied to larger scale systems for production of adult conditioned-media for C. elegans. Further, the adult retention device within the culture vessel can ensure that the whole process remains aseptic.

This thesis presents an analytical approach using Root-Loci method for designing optimum passive series RC snubbers for continuous-current synchronous buck switch mode power supply (SMPS). Synchronous buck SMPS is the most popular power converter topology found in modern consumer electronics. It offers relatively good efficiency to target the high-current and low-voltage requirements while it is also relatively inexpensive to implement. Passive series RC snubbers are simple, efficient and cost-effective open-loop equalizer circuit for synchronous buck SMPS. Its purpose is to control and to balance between the rate of rise and the overshoots of transient switching waveform in order to optimize efficiency and reliability Existing methods of RC snubber design are solely based on second-order approximation. It is investigated in this research that this approximation is highly inaccurate in SMPS applications because higher order equivalent models are required for the load path of the SMPS. The results using the RC snubbers obtained from existing method are shown to be unsatisfactory without correlation to the calculations and simulations based on second-order approximation. Optimum RC values obtained using Root-Loci approach presented in this thesis are shown to correlate to both Spice simulation and lab measurements.

Sliding mode controllers (SMC) with time delay and a rotor position observer are designed for the sensorless speed control of permanent magnet synchronous motor (PMSM) are proposed in this paper. Based on field-oriented principle, a flux SMC is designed to achieve quick flux control. And then a speed SMC with time delay is presented and compared with PI controller in the direct torque control framework. The effectiveness of the proposed control scheme under the load disturbance and parameter uncertainties is verified by simulation results.

This thesis presented a sensor-less permanent magnet synchronous motor (PMSM) driver for controlling air-conditioner rotary compressor speed. In this thesis, a quasi-sine pulse-width modulation (PWM) driving method was proposed. Furthermore, the current feedback control scheme and rotor magnet pole position detection were included. The system structure was implemented by using a digital signal processing (DSP) platform. The proposed driving scheme was compared with the square-wave driving without current feedback and six-step square-wave driving method with current feedback. Moreover, the passive and shunt semi-active power factor correction (PFC) technique were researched for the air-conditioner application. Experimental results demonstrated that the system power factor could be improved by the proposed shunt semi-active PFC method. Besides, the proposed sensor-less quasi-sine PWM driving method implemented in an air-conditioner compressor driver was capable of reducing the magnitude of rotational speed ripples, compressor vibration, and system power consumption.

BACKGROUND: An important characteristic of transitional cell carcinoma (TCC) is the formation of tumors in multiple sites throughout the whole urinary tracts. Two theories explain the pathophysiologic mechanisms of multifocal tumors: (1) intraluminal seeding, it indicates the multiple tumors come from a single transformed malignant cell with secondary seeding or migration at different sites, and (2) the field cancerization, carcinogens affect the urothelium at multiple sites, leading to numerous mutation and independent growth of multifocal polyclonal tumors. Multifocal urothelial carcinomas could come from intraluminal seeding or from field cancerization. However, the data of clinical behaviors between the two different tumor types are lacking. METHODS: Bilateral synchronous and metachronous primary TCC of the upper urinary tracts were derived from field cancerization. Recurrent bladder cancers following upper-tract tumors mostly come from intraluminal seeding. The recurrence, progression, and prognosis of the two different tumors were analyzed. RESULTS: Bilateral upper-tract urothelial carcinomas derived from field cancerization were frequently associated with renal insufficiency, which were more invasive and had poor prognosis than bladder tumors derived from intraluminal seeding. CONCLUSION: The clinical behaviors of the multiple urothelial tumors derived from field cancerization and from intraluminal seeding should be different.

Synchronous stream ciphers constitute an important class of symmetric ciphers. After the call of the eSTREAM project in 2004, 34 stream ciphers with different design approaches were proposed. In this thesis, we aim to provide a general framework to analyze stream ciphers statistically. Firstly, we consider stream ciphers as pseudo random number generators and study the quality of their output. We propose three randomness tests based on one dimensional random walks. Moreover, we theoretically and experimentally analyze the relations of various randomness tests. We focus on the ideas of algebraic, time memory tradeoff (TMTO) and correlation attacks and propose a number of chosen IV distinguishers. We experimentally observe statistical weaknesses in some of the stream ciphers that are believed to be secure.

Torsional vibration is an oscillatory angular twisting motion in the rotating members of a system. It can be deemed quite dangerous in that it cannot be detected as easily as other forms of vibration, and hence, subsequent failures that it leads to are often abrupt and may cause direct breakage of the shafts of the drive train. The need for sufficient analysis during the design stage of a rotating machine is, thus, well justified in order to avoid expensive modifications during later stages of the manufacturing process. In 1998, a project was initiated by the Turbomachinery Research Consortium (TRC) at Texas A&M University, College Station, TX, to develop a suite of computer codes to model torsional vibration of large drive trains. The author had the privilege of developing some modules in Visual Basic for Applications (VBA-Excel) for this suite of torsional vibration analysis codes, now collectively called XLTRC-Torsion. This treatise parleys the theory behind torsional vibration analysis using both the Transfer Matrix approach and the Finite Element approach, and in particular, validates the results generated by XLTRC-Torsion based on those approaches using experimental data available from tests on a 66,000 HP Air Compressor.