Analysis of Hardware Descriptions

The design process for integrated circuits requires a lot of analysis of circuit descriptions. An important class of analyses determines how easy it will be to determine if a physical component suffers from any manufacturing errors. As circuit complexities grow rapidly, the problem of testing circuits also becomes increasingly difficult. This thesis explores the potential for analysing a recent high level hardware description language called Ruby. In particular, we are interested in performing testability analyses of Ruby circuit descriptions. Ruby is ammenable to algebraic manipulation, so we have sought transformations that improve testability while preserving behaviour. The analysis of Ruby descriptions is performed by adapting a technique called abstract interpretation. This has been used successfully to analyse functional programs. This technique is most applicable where the analysis to be captured operates over structures isomorphic to the structure of the circuit. Many digital systems analysis tools require the circuit description to be given in some special form. This can lead to inconsistency between representations, and involves additional work converting between representations. We propose using the original description medium, in this case Ruby, for performing analyses. A related technique, called non-standard interpretation, is shown to be very useful for capturing many circuit analyses. An implementation of a system that performs non-standard interpretation forms the central part of the work. This allows Ruby descriptions to be analysed using alternative interpretations such test pattern generation and circuit layout interpretations. This system follows a similar approach to Boute's system semantics work and O'Donnell's work on Hydra. However, we have allowed a larger class of interpretations to be captured and offer a richer description language. The implementation presented here is constructed to allow a large degree of code sharing between different analyses. Several analyses have been implemented including simulation, test pattern generation and circuit layout. Non-standard interpretation provides a good framework for implementing these analyses. A general model for making non-standard interpretations is presented. Combining forms that combine two interpretations to produce a new interpretation are also introduced. This allows complex circuit analyses to be decomposed in a modular manner into smaller circuit analyses which can be built independently

Contributions to the design of power modules for electric and hybrid vehicles: trends, design aspects and simulation techniques

314 p.En la última década, la protección del medio ambiente y el uso alternativo de energías renovables están tomando mayor relevancia tanto en el ámbito social y político, como científico. El sector del transporte es uno de los principales causantes de los gases de efecto invernadero y la polución existente, contribuyendo con hasta el 27 % de las emisiones a nivel global. En este contexto desfavorable, la electrificación de los vehículos de carretera se convierte en un factor crucial. Para ello, la transición de la actual flota de vehículos de carretera debe ser progresiva forzando la investigación y desarrollo de nuevos conceptos a la hora de producir vehículos eléctricos (EV) y vehículos eléctricos híbridos (HEV) más eficientes, fiables, seguros y de menor coste. En consecuencia, para el desarrollo y mejora de los convertidores de potencia de los HEV/EV, este trabajo abarca los siguientes aspectos tecnológicos: - Arquitecturas de la etapa de conversión de potencia. Las principales topologías que pueden ser implementadas en el tren de potencia para HEV/EV son descritas y analizadas, teniendo en cuenta las alternativas que mejor se adaptan a los requisitos técnicos que demandan este tipo de aplicaciones. De dicha exposición se identifican los elementos constituyentes fundamentales de los convertidores de potencia que forman parte del tren de tracción para automoción.- Nuevos dispositivos semiconductores de potencia. Los nuevos objetivos y retos tecnológicos solo pueden lograrse mediante el uso de nuevos materiales. Los semiconductores Wide bandgap (WBG), especialmente los dispositivos electrónicos de potencia basados en nitruro de galio (GaN) y carburo de silicio (SiC), son las alternativas más prometedoras al silicio (Si) debido a las mejores prestaciones que poseen dichos materiales, lo que permite mejorar la conductividad térmica, aumentar las frecuencias de conmutación y reducir las pérdidas.- Análisis de técnicas de rutado, conexionado y ensamblado de módulos de potencia. Los módulos de potencia fabricados con dies en lugar de dispositivos discretos son la opción preferida por los fabricantes para lograr las especificaciones indicadas por la industria de la automoción. Teniendo en cuenta los estrictos requisitos de eficiencia, fiabilidad y coste es necesario revisar y plantear nuevos layouts de las etapas de conversión de potencia, así como esquemas y técnicas de paralelización de los circuitos, centrándose en las tecnologías disponibles.Teniendo en cuenta dichos aspectos, la presente investigación evalúa las alternativas de semiconductores de potencia que pueden ser implementadas en aplicaciones HEV/EV, así como su conexionado para la obtención de las densidades de potencia requeridas, centrándose en la técnica de paralelización de semiconductores. Debido a la falta de información tanto científica como comercial e industrial sobre dicha técnica, una de las principales contribuciones del presente trabajo ha sido la propuesta y verificación de una serie de criterios de diseño para el diseño de módulos de potencia. Finalmente, los resultados que se han extraído de los circuitos de potencia propuestos demuestran la utilidad de dichos criterios de diseño, obteniendo circuitos con bajas impedancias parásitas y equilibrados eléctrica y térmicamente. A nivel industrial, el conocimiento expuesto en la presente tesis permite reducir los tiempos de diseño a la hora de obtener prototipos de ciertas garantías, permitiendo comenzar la fase de prototipado habiéndose realizado comprobaciones eléctricas y térmicas

OPTIMIZING MONARCH BUTTERFLY AND BEE CONSERVATION EFFORTS IN THE URBAN LANDSCAPE

The eastern migratory population of monarch butterflies (Danaus plexippus) is in serious decline. Most of the efforts to conserve this iconic insect focus on habitat restoration in the US Midwest. Often overlooked are small butterfly-centric gardens that can act as stepping stones between urban and rural areas. These studies aim to optimize the conservation value of such gardens. Eight milkweed (Asclepias) species varying in height, form, and leaf shape were compared over two years in a common-garden experiment. I measured milkweed growth, rhizome spread, and bloom periods, conducted bi-weekly counts of monarch eggs and larvae, evaluated suitability for larvae, and quantified bee visitation. More monarchs were found on taller, broad-leaved milkweeds, but there was relatively little difference in larval performance. Asclepias tuberosa attracted the greatest number of bees, whereas bee genus diversity was greatest on A. verticillata. Gardens containing the identical mix of milkweeds, flowering plants, and grasses but arranged in three different spatial configurations were monitored for monarch colonization over two years. Monarch eggs and larvae were 2.5–4 times more abundant in gardens having milkweeds evenly spaced around the perimeter than in gardens in which milkweeds were surrounded by or intermixed with the other plants. Predator populations were similar in all garden designs. In a corollary experiment, female monarchs laid significantly more eggs on plants that were fully accessible than on milkweeds surrounded by non-host grasses. In addition, I monitored monarch use in 22 citizen-planted gardens containing milkweed and nectar plants in relation to their botanical composition, layout, and surrounding hardscape. Significantly more monarchs were found in gardens having milkweeds spatially isolated and in gardens having 100 m north/south access unimpeded by structures. The high-profile model system of milkweeds and monarchs was used to test if cultivars have equal conservation value as native wild-types. In replicated gardens I compared two species of milkweed (A. incarnata and A. tuberosa) and three of their cultivars over two years, measuring plant size, defensive characteristics, colonization by monarchs, suitability as host plants, and the bee assemblages, and Lepidopteran communities of each. I found that horticultural selection enhanced defensive characteristics in some cultivars, but did not influence larval growth and development. I also compared defensive characteristics of non-native milkweeds (A. curassavica and Gomphocarpus physocarpus) and their cultivars in the greenhouse and observed similar results. The European paper wasp or EPW (Polistes dominula) predominantly builds its nests on structures. These invasive wasps forage for soft bodied arthropods, including monarch larvae, which may cause conservation gardens to become ecological traps. I confirmed EPW is the predominant Polistes spp. in urban gardens, documented outcomes between EPW and monarch larvae, and found that predation by EPW was more common in urban gardens than rural grasslands away from structures. I found that the invasive Japanese beetle (Popillia japonica) aggregates and feeds on flowers of A. syriaca, the monarch’s most important host plant, reducing seed set by \u3e90%. The beetle’s ongoing incursion into the monarch’s key breeding grounds in the US Midwest is likely to limit pollination and outcrossing of wild and planted milkweeds, reducing their capacity to colonize new areas via seeds

Wireless sensor networks using network coding for structural health monitoring

Wireless Sensor Networks (WSNs) have been deployed for the purpose of structural health monitoring (SHM) of civil engineering structures, e.g. bridges. SHM applications can potentially produce a high volume of sensing data, which consumes much transmission power and thus decreases the lifetime of the battery-run networks. We employ the network coding technique to improve the network efficiency and prolong its lifetime. By increasing the transmission power, we change the node connectivity and control the number of nodes that can overhear transmitted messages so as to hopefully realize the capacity gain by use of network coding. In Chapter 1, we present the background, to enable the reader to understand the need for SHM, advantages and drawbacks of WSNs and potential the application of network coding techniques has. In Chapter 2 we provide a review of related research explaining how it relates to our work, and why it is not fully applicable in our case. In Chapter 3, we propose to control transmission power as a means to adjust the number of nodes that can overhear a message transmission by a neighbouring node. However, too much of the overhearing by high power transmission consumes aggressively limited battery energy. We investigate the interplay between transmission power and network coding operations in Chapter 4. We show that our solution reduces the overall volume of data transfer, thus leading to significant energy savings and prolonged network lifetime. We present the mathematical analysis of our proposed algorithm. By simulation, we also study the trade-offs between overhearing and power consumption for the network coding scheme. In Chapter 5, we propose a methodology for the optimal placement of sensor nodes in linear network topologies (e.g., along the length of a bridge), that aims to minimise the link connectivity problems and maximise the lifetime of the network. Both simple packet relay and network coding are considered for the routing of the collected data packets towards two sink nodes positioned at both ends of the bridge. Our mathematical analysis, verified by simulation results, shows that the proposed methodology can lead to significant energy saving and prolong the lifetime of the underlying wireless sensor network. Chapter 6 is dedicated to the delay analysis. We analytically calculate the gains in terms of packet delay obtained by the use of network coding in linear multi-hop wireless sensor network topologies. Moreover, we calculate the exact packet delay (from the packet generation time to the time it is delivered to the sink nodes) as a function of the location of the source sensor node within the linear network. The derived packet delay distribution formulas have been verified by simulations and can provide a benchmark for the delay performance of linear sensor networks. In the Chapter 7, we propose an adaptive version of network coding based algorithm. In the case of packet loss, nodes do not necessary retransmit messages as they are able to internally decide how to cope with the situation. The goal of this algorithm is to reduce the power consumption, and decrease delays whenever it can. This algorithm achieves the delay similar to that of three-hop direct-connectivity version of the deterministic algorithm, and consumes power almost like one-hop direct-connectivity version of deterministic algorithm. In very poor channel conditions, this protocol outperforms the deterministic algorithm both in terms of delay and power consumption. In Chapter 8, we explain the direction of our future work. Particularly, we are interested in the application of combined TDMA/FDMA technique to our algorithm.Open Acces

Superwettability fibrous filters for aerosol oil-mist filtration

This study focused on how superwettability affect the aerosol oil mist filtration performance of fibrous filters. It pointed to the surface wettability manipulation, characterization, filtration performance and mechanisms. The findings provided a strategy to largely improve filtration efficiency without increasing the flow resistance

Efficient Execution of Sequential Instructions Streams by Physical Machines

Any computational model which relies on a physical system is likely to be subject to the fact that information density and speed have intrinsic, ultimate limits. The RAM model, and in particular the underlying assumption that memory accesses can be carried out in time independent from memory size itself, is not physically implementable. This work has developed in the field of limiting technology machines, in which it is somewhat provocatively assumed that technology has achieved the physical limits. The ultimate goal for this is to tackle the problem of the intrinsic latencies of physical systems by encouraging scalable organizations for processors and memories. An algorithmic study is presented, which depicts the implementation of high concurrency programs for SP and SPE, sequential machine models able to compute direct-flow programs in optimal time. Then, a novel pieplined, hierarchical memory organization is presented, with optimal latency and bandwidth for a physical system. In order to both take full advantage of the memory capabilities and exploit the available instruction level parallelism of the code to be executed, a novel processor model is developed. Particular care is put in devising an efficient information flow within the processor itself. Both designs are extremely scalable, as they are based on fixed capacity and fixed size nodes, which are connected as a multidimensional array. Performance analysis on the resulting machine design has led to the discovery that latencies internal to the processor can be the dominating source of complexity in instruction flow execution, which adds to the effects of processor-memory interaction. A characterization of instruction flows is then developed, which is based on the topology induced by instruction dependences

Impact of the invasive ant Linepithema humile on native ant assemblages on the western slopes of Table Mountain and implications for ant-butterfly associations

The Argentine Ant, Linepithema humile (Hymenoptera: Formicidae), is one of the world's most successful invasive species and invades undisturbed Fynbos habitats in South Africa, displacing native arthropod species and affecting interspecific associations. In order to assess the impact of Li. humile on native ant assemblages and associations between ants and myrmecophilous butterflies (Lepidoptera: Lycaenidae) on the western slopes of Table Mountain (Cape Town, South Africa), adult butterfly density was scored and distribution of food plants were assessed at two sites

Micro-Scale Flapping Wings for the Advancement of Flying MEMS

This research effort presents conceptual micro scale air vehicles whose total dimensions are less than one millimeter. The initial effort was to advance the understanding of micro aerial vehicles at sub-millimeter dimensions by fabricating and testing micro scale flapping wings. Fabrication was accomplished using a surface micromachining process called PolyMUMPs™. Both rigid mechanical structures and biomimetic devices were designed and fabricated as part of this effort. The rigid mechanical structures focused on out of plane deflections with solid connections and assembling a multiple hinge wing structure through the aid of residual stress. These devices were actuated by double hot arm thermal actuators. The biomimetic structures derived from three different insect wings to include; the dragonfly, house fly, and butterfly were selected based off of an attribute that each insect possesses in nature. The dragonfly was chosen for its high maneuverability and hovering capabilities. The house fly wing was chosen because of its durability and the butterfly wing was chosen because of its flexibility. The fabricated wings utilize a thermal bimorph structure consisting of polysilicon and gold which allows device actuation through joule heating. The released micro wings had an initial upward deflection due to residual stress between the gold and polysilicon material layers. Joule heating, from an applied bias, forces the wing to deflect downward due to the coefficient of thermal expansion mismatch between the material layers. Each fabricated bio-wing structure was tested for deflection range as well as operating frequency. From the experimental testing of the micro scale flapping bio-wings, aerodynamic values were calculated to include; aspect ratio, reduced frequency in a hover, Reynolds number of a hovering device, drag force, and gravitational force. The research verified insect based wings on the micro scale are capable of producing the desired flapping motion

Woodward Willis Building- Fire and Life Safety Evaluation

This project report is an academic exercise, completed as part of the MS Fire Protection Engineering program at California Polytechnic State University. This project is a culminating report with regards to life safety analysis of the Woodward Willis Building located in Detroit Michigan, which utilizes the fundamental and applied courses of the fire protection engineering program. The analysis is based on a prescriptive analysis of the building and its features, and also a performance analysis which entails the life safety aspect of the building. The analysis of the building is performed in accordance with NFPA 101 Life Safety Code 2015 Edition and its references as well as being supplemented by the SFPE Handbook 5th Edition. The building is analyzed as a new structure as it is currently under construction. The Woodward Willis building is three stories and is comprised of a technical college, storefronts, and a parking garage. These areas reveal occupancy classifications of educational, mercantile, and storage to be considered in the analysis. The building is situated on the northwest corner at the intersection of Woodward Avenue and Willis Street with frontage on each road. The north frontage of the building faces a factory and is separated by an alley. This alley is greater than 10 feet wide, which allows a separation distance fire resistance rating of 0 hours along this side of the building. The east side of the building faces a McDonald\u27s property and is also greater than 10 feet, allowing it to have required fire resistance rating on the exterior of the building as well. The prescriptive analysis concludes that, in general the building is in compliance with the applicable codes and standards from a fire protection standpoint. These results are based on the information available at this time and are not taking into consideration any modifications to the construction process beyond this time. A final as built scenario shall include final testing and inspection of all the systems in a typical scenario in which the building will be used. At this point, the building shall have all fire protection systems fully commissioned by a certified fire protection contractor before occupancy. The performance based analysis addressed the life safety of the building in the event of a fire. The building was inspected during a period when the rooms within were partially furnished during construction. In this state, it was determined that the most likely fire scenario would occur via an electrical failure on a makeshift cardboard desk in a classroom on the 3rd floor. The analysis revealed that the building meets the performance criteria of the Life Safety Code in the current stage of the building. In the analyzed fire scenario, the egress capabilities are proven to exceed the potential for occupants to be harmed by the fire. This scenario would need to be confirmed compatible under normal operating conditions to remain true. If the conditions of the building are changed or altered, the scenario would need to be readdressed and analyzed to meet the status of the building