Dynamic dead variable analysis (DDVA) extends traditional static dead variable analysis (SDVA) in the context of model checking through the use of run-time information. The analysis is run multiple times during the course of model checking to create a more precise set of dead variables. The DDVA is evaluated based on the amount of memory used to complete model checking relative to SDVA while considering the extra overhead required to implement DDVA. On several models with a complex control flow graph, DDVA reduces the amount of memory needed by 38-88MB compared to SDVA with a cost of 36 bytes of memory verhead. On several models with loops, DDVA achieved no additional reduction compared to SDVA while requiring no more memory than SDVA.

With gas prices on the rise, the demand for high-mileage and low pollution vehicles has taken on an unprecedented role in our society. The production and implementation of electric and hybrid-electric vehicles has recently been a large focus of all major automobile manufacturers. Although these new vehicles have begun to solve much of the expensive fuel consumption and air pollution problems that our economy faces, the initial cost of these vehicles has proven to still be too expensive to capture a significant portion of the market. The further advancement of this technology must not only continue to focus on better fuel efficient and decreased pollution producing vehicles, but also decrease the cost of these vehicles to make them more available and enticing to the general public. Results from this research include one potential solution to reduce the cost of electric and hybrid-electric vehicles. Previous research performed in this area has led to the investigation and bench-top testing of a special type of mechanical system known as a Planetary Differential (PD). An exploration of the functionality of this system has shown that the PD can simplify expensive and complex electronic control systems for electric and hybrid-electric vehicles, thus reducing the cost to the consumer. In this study, fundamental speed, torque and power relationships for the PD were developed and tested under various loading conditions. Advantages and disadvantages of the PD, as compared to other similar mechanical systems, are identified and outlined. Recommendations for future work and implementation of the PD in electric and/or hybrid-electric vehicles are presented herein.

Research recently conducted at the University of Central Florida involving crashes on Interstate-4 in Orlando, Florida has led to the creation of new statistical and neural networks models that are capable of determining the crash risk on the freeway (Abdel-Aty et al., 2004; 2005, Pande and Abdel-Aty, 2006). These models are able to calculate rear-end and lane-change crash risks along the freeway in real-time through the use of static information at various locations along the freeway as well as real-time traffic data obtained by loop detectors. Since these models use real-time traffic data, they are capable of calculating rear-end and lane-change crash risk values as the traffic flow conditions are changing on the freeway. The objective of this study is to examine the potential benefits of combining two ITS strategies (Ramp Metering and Variable Speed Limits strategies) for reducing the crash risk (both rear-end and lane-change crash risks) along the I-4 freeway. Following this aspect, a 36.25-mile section of I-4 running though Orlando, FL was simulated using the PARAMICS micro-simulation program. Gayah (2006) used the same network to examine the potential benefits of two ITS strategies separately (Route Diversion and Ramp Metering) for reducing the crash risk along the freeway by changing traffic flow parameters. Cunningham (2007) also used the same network to examine the potential benefits of implementing Variable Speed Limits strategy for reducing the crash risk along the freeway. Since the same network is used, the calibration and validation procedures used in this study are the same as these previous two studies. This study simulates three volume loading scenarios on the I-4 freeway. These are 60, 80 and 90 percent loading scenarios. From the final experimental design for the 60 % loading, it was concluded that implementing VSL strategy only was more beneficial to the network than either implementing Ramp Metering everywhere (through the whole network) in conjunction with VSL everywhere or implementing Ramp Metering downtown (in downtown areas only) in conjunction with VSL everywhere. This was concluded from the comparison of the results of this study with the results from Cunningham (2007). However, either implementing Ramp Metering everywhere or downtown in conjunction with VSL everywhere showed safety benefits across the simulated network as well as a reduction in the total travel time. The best case for implementing Ramp Metering everywhere in conjunction with VSL everywhere was using a homogeneous speed zone threshold of 2.5 mph, a speed change distance of half speed zone and a speed change time of 5 minutes in conjunction with a 60 seconds cycle length for the Zone algorithm, a critical occupancy of 0.17 and a 30 seconds cycle length for the ALINEA algorithm. And the best case for implementing Ramp Metering downtown in conjunction with VSL everywhere was using a homogeneous speed zone threshold of 2.5 mph, a speed change distance of half speed zone and a speed change time of 10 minutes in conjunction with a 60 seconds cycle length for the Zone algorithm, a critical occupancy of 0.17 and a 30 seconds cycle length for the ALINEA algorithm. For the 80 % loading, it was concluded that either implementing Ramp Metering everywhere in conjunction with VSL everywhere or implementing Ramp Metering downtown in conjunction with VSL everywhere was more beneficial to the network than implementing VSL strategy only. This was also concluded from the comparison of the results of this study with the results from Cunningham (2007). Moreover, it was concluded that implementing Ramp Metering everywhere in conjunction with VSL everywhere showed higher safety benefits across the simulated network than implementing Ramp Metering downtown in conjunction with VSL everywhere. Also, both of them increased the total travel time a bit, but this was deemed acceptable. Additionally, both of them had successive fluctuations and variations in the average lane-change crash risk vs. time step. The best case for implementing Ramp Metering everywhere in conjunction with VSL everywhere was using a homogeneous speed zone threshold of 5 mph, a speed change distance of half speed zone and a speed change time of 30 minutes in conjunction with a 60 seconds cycle length for the Zone algorithm, a critical occupancy of 0.17 and a 30 seconds cycle length for the ALINEA algorithm. And the best case for implementing Ramp Metering downtown in conjunction with VSL everywhere was using a homogeneous speed zone threshold of 5 mph, a speed change distance of half speed zone and a speed change time of 30 minutes in conjunction with a 60 seconds cycle length for the Zone algorithm, a critical occupancy of 0.17 and a 30 seconds cycle length for the ALINEA algorithm. Searching for the best way to implement both Ramp Metering and VSL strategies in conjunction with each other, an indepth investigation was conducted in order to remove the fluctuations and variations in the crash risk with time step (through the entire simulation period). The entire simulation period is 3 hours, and each time step is 5 minutes, so there are 36 time steps representing the entire simulation period. This indepth investigation led to the idea of not implementing VSL at consecutive zones (using either a gap of one zone or more). Then this idea was applied for the best case of implementing Ramp Metering and VSL everywhere at the 80 % loading, and the successive fluctuations and variations in the crash risk with time step were removed. Moreover, much better safety benefits were found. So, this confirms that this idea was very beneficial to the network. For the 90 % loading, it was concluded that implementing Ramp Metering strategy only (Zone algorithm in downtown areas, and ALINEA algorithm in non downtown areas) was more beneficial to the network than implementing Ramp Metering everywhere in conjunction with VSL everywhere. This was concluded from the comparison of the results of this study with the results from Gayah (2006). However, implementing Ramp Metering everywhere in conjunction with VSL everywhere showed safety benefits across the simulated network as well as a reduction in the total travel time. The best case was using a homogeneous speed zone threshold of 2.5 mph, a speed change distance of the entire speed zone and a speed change time of 20 minutes in conjunction with a 60 seconds cycle length for the Zone algorithm, a critical occupancy of 0.17 and a 30 seconds cycle length for the ALINEA algorithm. In summary, Ramp Metering was more beneficial at congested situations, while Variable Speed Limits were more beneficial at free-flow conditions. At conditions approaching congestion, the combination of Ramp Metering and Variable Speed Limits produced the best benefits. These results illustrate the significant potential of ITS strategies to improve the safety and efficiency of urban freeways.

The purpose of this study was to determine which variables contribute to high school dropout in a north central Mississippi school district’s only high school. The study population consisted of 301 students who enrolled as freshman in a north central Mississippi school district’s only high school during the 2002-2003 academic year and could have graduated from high school in 2006. Student data were obtained from the Mississippi Student Information System (MSIS) database, which contained all relevant information to this study. Data were collected on the following variables: gender, ethnicity, age, disciplinary infractions, whether or not a student was socially promoted, number of grades retained, number of absences, subject area testing scores, ninth grade retention, and special education enrollment. The findings of this study indicated there were relationships between the criterion variable, high school dropout, and the following predictor variables: age, ethnicity, whether or not a student was socially promoted, number of absences, number of grades retained, ninth grade. retention, and disciplinary infractions. The findings from this investigation also suggested that both socially promoted and students with high numbers of absences were more likely to drop out of high school than those who were not socially promoted, or had fewer absences.

Isostatic frameworks are statically determinate trusses that are self contained (Le. they exist independent of support or foundation). Isostatic frameworks have been widely used as supporting structures, and recently they have been used as the structure for parallel manipulators. These truss-based manipulators could potentially solve the problems facing conventional manipulators and could make the design of high-degree-of-freedom manipulators feasible. The rigorous scientific study of isostatic frameworks and manipulators based on their structure has been limited. Recent developments in the design of large space structures and truss-based manipulators, however, demand rigorous design and mathematical tools. This dissertation provides a general theory for the design of structures based on frameworks and methods to analyze the kinematics of truss-based manipulators. The objective of the first part of this dissertation is to solve the problems of identification, generation and classification of isostatic frameworks in greater depth than in any past work in this area. Original methods are discussed for the enumeration and generation of isostatic frameworks. The first part also presents an original method to determine the geometry of general frameworks and an improved method to find the forces in their members. The determination of geometry and forces are critical areas in structural design. The second part of this dissertation presents a case study on one of the candidates for manipulator applications, the double-octahedral manipulator. The kinematic analyses of the double-octahedral manipulator includes methods to perform forward and inverse kinematic analysis, velocity and acceleration analysis, singularity analysis and workspace analysis. The closed-form solution to the inverse analysis presented herein is a major breakthrough in the development of the double-octahedral manipulator. Other analysis, such as velocity and acceleration, singularity, and workspace, depend on the inverse solution. It is believed that these solutions will help narrow the gap between theory and application of truss-based manipulators. The determination of singularities and works paces are application of recent ideas of other researchers. However, original implementations of these ideas have yielded astonishing results. The Jacobian and Hessian matrix presented in this dissertation should help in developing the control scheme for this device. C-Ianguage program codes for several of the methods are also provided. The methods have been tested based on the results obtained from these programs. The position analysis algorithms have also been tested on real hardware. Some of the methods developed here have been successfully employed for simulated and experimental vibration control studies. / Ph. D.

[EN] This Thesis presents a set of tools that allows the improvement of the digital video coding efficiency by exploiting the fundamentals of the state of the art video coding standards. This work has been focused both on research and on the application of the results to the encoding of digital video in real time mobile environments. The first contribution is an automatic shot change detection algorithm integrated in the encoding process. This algorithm is based on the monitoring of the coding mode of the macroblocks of the sequence, and the proper definition of a set of parameters provides excellent detection rates, precision and recall. The results also indicate an improvement on the encoded video quality when these detection techniques are used, which triggers the definition of a content-based keyframe selection algorithm. With this method, the optimal position of reference pictures can be determined. These keyframes are then used by the encoder to perform temporal prediction of the subsequent frames, which improves the compression rate and the encoded video quality (both objective and subjective). This quality improvement is the main objective of this Thesis. In the last part of this work, a rate control algorithm for variable bitrate and frame rate environments has been defined, being able to generate a bitstream that quickly follows the varying conditions of the mobile channel. In parallel to all this work, a set of training and test sequences has been obtained, providing an optimal environment for the design, development, configuration, optimization and test of the algorithms described here. / [ES] Esta tesis presenta un conjunto de herramientas que permiten mejorar la eficiencia de codificación de vídeo mediante la explotación de los fundamentos en los que se basan los principales estándares de codificación actuales. El trabajo se ha orientado tanto a la investigación como a la aplicación de los resultados a la codificación de vídeo en tiempo real en entornos móviles. En primer lugar se ha definido un algoritmo de detección automática de cambios de plano para entornos de tiempo real integrado en el proceso de codificación. Este algoritmo está basado en la monitorización del modo de codificación de los macrobloques de la secuencia y la correcta definición de un conjunto de parámetros consigue unas tasas de detección, una precisión y una eficacia superiores a otros métodos similares existentes en la literatura. Los resultados muestran también una mejora en la calidad del vídeo codificado al aplicar estas técnicas de detección, lo que lleva a la definición de un algoritmo de selección de imágenes de referencia (keyframes) basado en el contenido. Así se pueden obtener las posiciones óptimas para las imágenes de referencia utilizadas por el codificador para realizar predicciones temporales que aumentan la calidad tanto objetiva como subjetiva del vídeo codificado, lo que constituye a su vez el objetivo principal de esta tesis. Por último, se ha diseñado un algoritmo de control de tasa capaz de obtener un bitstream que se adapta rápidamente a los cambios tanto de bitrate como de tasa de imágenes por segundo producidos en el canal móvil. Paralelamente, se ha obtenido un conjunto de secuencias de entrenamiento y test que proporcionan un entorno óptimo para el diseño, desarrollo, configuración, optimización y prueba de los algoritmos aquí descritos. / [CA] Aquesta tesi presenta un conjunt de ferramentes que permeten millorar la eficiència de codificació de vídeo digital mitjançant l'explotació dels fonaments en els que es basen els principals estàndards de codificació actuals. El treball ha estat orientat tant a la investigació com a l'aplicació dels resultats a la codificació de vídeo en temps real en entorns mòbils. En primer lloc s'ha definit un algoritme de detecció automàtica de canvis de plànol integrat en el propi procés de codificació. Aquest algoritme s'ha basat en la monitorització del mode de codificació dels macroblocs de la seqüència, i la correcta definició d'un conjunt de paràmetres de configuració permet aconseguir unes taxes de detecció, una precisió i una eficàcia superiors a altres mètodes similars presents a la literatura. Aquests resultats també indiquen una millora en la qualitat del vídeo codificat al aplicar aquestes tècniques de detecció la qual ens porta a la definició d'un algoritme de selecció d'imatges de referència (keyframes) basada en el contingut. Amb aquest algoritme es poden obtenir les posicions òptimes per a les imatges de referència utilitzades pel codificador per a realitzar prediccions temporals òptimes que augmenten la qualitat tant objectiva com subjectiva del vídeo codificat. Amb esta millora s'assoleix l'objectiu principal d'aquesta tesi. Per últim, s'ha dissenyat un algoritme de control de taxa capaç d'obtenir un bitstream que s'adapta ràpidament als canvis tant de bitrate com de taxa d'imatges per segon requerits per les condicions canviants del canal mòbil. Paral·lelament s'ha obtingut un conjunt de seqüències d'entrenament i test que permet disposar d'un entorn òptim per al disseny, desenvolupament, configuració, optimització i prova dels algoritmes descrits en aquestes fulles. / Usach Molina, P. (2015). TÉCNICAS DE MEJORA DE LA EFICIENCIA DE CODIFICACIÓN DE VÍDEO [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59446

The research presented in this thesis regards walking of quadruped robots, and particularly the walking of the Warp1 robot. The motivation for the robot is to provide a platform for autonomous walking in rough terrain. The thesis contains six papers ranging from development tools to actuation of robot legs. The first paper describes the methods and tools made for control development. These tools feature: programming of the robot without low level coding (C-code); that the controller has to be built only once for simulation and experiments; and that names of variables and constants are unchanged through the chain of software Maple -- Matlab -- Simulink -- Real~Time~Workshop -- xPC--Target. Three controllers, each making the robot walk are presented. The first controller makes the robot walk using the crawl gait. The method uses static stability as method for keeping balance and the instantaneous trunk motions are given by a concept using the so called weight ratios. A method for planning new footholds based on the positions of the existing footholds is also proposed and the controller experimentally verified. The second walking controller shows that the robot also can walk dynamically using the trot gait. The method proposed uses information from ground contact sensors on the feet as input to control balance, instead of, which is common, inertial sensors. It is experimentally verified that Warp1 can trot from level ground onto a slope and turn around while staying balanced. The main ideas of these two walking controllers are fused in the third which enables smooth transitions between crawl and trot. The idea of using the ground contact sensors from the first controller is here used to estimate the position of the center of mass. This controller uses weight ratios in the gait crawl as well as in the dynamic gait trot. Hence, the method of using weight ratios is not only useful for static stability for which it was originally intended. The controller is experimentally verified on Warp1. The Warp1 robot weighs about 60 kg, has 0.6 m long legs with three actuated joints on each. The speed and strength is sufficient only for slow walking, even though the installed power indicates that it should be enough for faster walking. The reason is that a walking robot often needs to be strong but slow when the feet are on the ground and the opposite when in the air. This can not be achieved with the motors and transmissions currently used. A transmission called the passively variable transmission (PVT) is proposed which enhance motor capabilities of robot joints. It is elastic, nonlinear and conservative. Some general properties for elastic transmissions are derived such that they can be compared with conventional transmissions. The PVT gives strong actuation at large loads and fast actuation at small loads. The proposed transmission is compared to a conventional transmission for a specific task, and the result is that a smaller motor can be used. / QC 20100831

Designing CMOS linear transmitter front-end, specially the power amplifiers (PAs), in multi-band wireless transceivers is a major challenge for the single-chip integration of a CMOS radio. In some of the linear PA systems, for example, polar- or predistortion-PA system, amplitude and phase control circuits are used to suppress the distortion produces by the PA core. The requirements of these controlling circuits are much different from their conventional role in a receiver or a phase array system. In this dissertation, the special design issues will be addressed, and the circuit topologies of the amplitude and phase controllers will be proposed. In attempt to control the high-power input signal of a PA system, a highly linear variable attenuator with adaptive body biasing is first introduced. The voltage swing on the signal path is intentionally coupled to the body terminal of the triple-well NMOS devices to reduce their impedance variation. The fabricated variable attenuator shows a significant improvement on linearity as compared to previous CMOS works. The results of this research are then used to build a variable gain amplifier for linear PA systems that requires gain of its amplitude tuning circuits. Different from the conventional attenuator-based VGAs, the high linearity of the suggested attenuator allows it to be put after the gain stage in the presented VGA topology. This arrangement along with the current boosting technique gives the VGA a better noise performance while having a linear-in-dB tuning curve and better worst-case linearity. The following part of the dissertation is about a compact, linear-in-degree tuned variable phase shifter as the phase controller in the PA system. This design uses a modified RC poly-phase filter to produce a set of an orthogonal phase vectors with smaller loss. A specially designed control circuit combines these vectors and generates an output signal with different phases, while having very small gain mismatches at different phase setting. The proposed amplitude and phase control circuits are then verified with a system level analysis. The results show that the proposed designs successfully reduce the non-linear effect of a wireless transmitter.

Master of Science / Department of Architectural Engineering and Construction Science / Julia A. Keen / This report addresses the operation, use, and design of air-to-air variable refrigerant flow systems, also known as VRF. Relatively new to the United States, these HVAC systems have potential to reduce energy consumption and utility costs in the correct applications. Although useful in many applications, the best building types for VRF are those requiring a large number of zones and with low ventilation air requirements. The report explains design and system selection considerations and accordingly presents two flowcharts to help designers implement this system. To show how the system compares to traditional technologies in terms of efficiency and cost, the report presents results from several studies comparing VRF to other systems. In addition, an energy modeling study is conducted to clarify the effect of climate on the system; this study established air-to-air VRF as having highest energy consumption in dry, southern climates, based on energy use and operating costs. With this report, HVAC designers can learn when air-to-air VRF is an acceptable method for providing heating and cooling in a building.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / IRIG-106 Chapter 5 describes a method for encoding voice using a simple circuit to reduce the overall bit rate and still achieve good quality voice. This well described Continuously Variable Slope Delta Modulation (CVSD) circuit can be obtained using analog parts. A more stable implementation of CVSD can be obtained by designing an anti-aliasing input filter, an A/D converter, and logic. This paper describes one implementation of the CVSD using a standard A/D converter and logic.