No description available.

No description available.

No description available.

No description available.

No description available.

The oscillometric method for blood pressure measurement has been known for over a century. It was overshadowed by the classic stethoscope and cuff method until more recently when its ease of automation became useful. It is now found in the automated blood pressure cuffs used in hospitals, doctor's offices, pharmacies, and devices sold for home use. It still challenges accurate blood pressure measurement, however, due to its difficulty in compensating for pregnancy, age, hypo-, and hypertension. Global sensitivity analysis methods were used to develop a model that focuses on the most important system parameters. The most influential biological and design parameters were identified allowing the removal or fixing of less influential parameters, and the replacement of subsystems with linear models, with minimal effect on the overall system accuracy. The developed model allows for the investigation and development of new methods for extracting parameter information from the oscillometric signals. This is illustrated by the development of a method to extract the artery's cross-sectional area from standard oscillometric output. The system design requirements for accurate measurement of blood pressure are examined and discussed with recommendations for system parameter adjustment. The model's performance and usefulness is highlighted with modelled case studies of potential real-world applications for subjects with parameters or inputs for which the oscillometric method would find it difficult to compensate. Through the use of the developed model to compensate for the system errors, the measurement error can be reduced by half. Highlighting the important system parameters allows the engineer to focus on choosing the design parameters over which she or he has control. The system model provides the ability to experiment with the cuff design choices and provides information regarding system performance under conditions that are historically difficult to measure accurately. The developed model's usefulness is illustrated by applying it to parameter extraction, and to the compensation of oscillometric blood pressure readings.

This thesis documents the design and analysis of a low-power integrated ultra-wideband (UWB) receiver that is well suited for usage in medium to low rate, location aware communication systems. For the first time, this receiver design explores and exploits the unique properties of UWB pulse technology. By exploiting low emission power limit and pulse based communication, RF circuits have been designed with reduced linearity to achieve low-power operation and better circuit performance. The receiver design in this thesis follows a top-down approach which begins by focusing on UWB-specific issues such as signal characteristics, modulation schemes, potential advantages, and design challenges. Next, different receiver architectures are evaluated in terms of their circuit complexity, power consumption, and levels of integration. The impact of various analog non-idealities on the performance of UWB systems is also analysed in detail. After evaluating the performance of UWB systems operating with non-linear frontends, the use of pulse doublets is introduced, for the first time, to mitigate nonlinearityinduced distortion. Simulation results demonstrate that under non-linear operating conditions, significant BER improvements can be achieved by using filtering, pulse doublet, and direct sequence spread spectrum techniques. When ADC quantization effects are included in the receiver, analysis shows that quantization noise dominates distortion-induced BER degradation when two or three bits ADCs are employed. Consequently, reduced front-end linearity requirements can be tolerated in exchange for improvements in the more critical circuit parameters of the UWB receiver. By adopting the sub-linear circuit design approach, a direct-conversion receiver prototype is implemented in the 0.5 um SOS CMOS technology according to specifications determined from system-level Simulink simulations. This highly integrated receiver prototype contains a low-noise amplifier, a 4-GHz frequency synthesizer, mixers, baseband amplifiers and filters, and 2-GSps two-bit analog-to-digital converters. The receiver prototype consumes 75-mW of power, the lowest amount for reported UWB receivers operating in the 3.1 to 10.6-GHz band. Complete end-to-end simulations of the system are performed in Simulink, revealing an achievable BER of approximately 8x10e-4 Finally, a novel 79-uW 5.6-GHz CMOS frequency divider with on-chip temperature and processing compensation have been designed. The divider, designed in a 0.25 um SOS-CMOS technology, occupies 35 x 25 um2 and achieves an operating frequency of 5.6-GHz while consuming 79-uW at a supply voltage of 0.8V. The power efficiency of 143-GHz/mW is one of the highest achieved among conventional CMOS dividers. When combined with a simple and effective compensation submodule, the proposed divider is shown to achieve process and temperature-insensitive operation in a 5-GHz UNII band frequency synthesizer.

Compressed air has in the past been considered as a free resource in heavy vehicles.The recent years work to minimize fuel consumption has however made airconsumption an interesting topic for the manufactures to investigate further. Compressed air has many different applications in heavy vehicles. One importantconsumer of compressed air is the brake system, which would not work at allwithout compressed air. The compressed air is produced by a compressor attachedto the engine. A leakage in the system will force the compressor to work longer,which leads to an increased fuel consumption. It is of large interest to have a diagnosis system that can detect leakages, and ifpossible also provide information about where in the system the leakage is present.This information can then be used to repair the leakage at the next service stop. The diagnosis system that is developed in this thesis is based on model baseddiagnosis and uses a recursive least mean square method to estimate the leakagearea. The results from the validation show that the algorithm works well forleakages of the size 1-10 litres/minute. The innovative isolation algorithm givesfull fault isolation for a five circuit system with only three pressure sensors. / Tryckluft i lastbilar har tidigare ansetts vara en fri resurs. Den senaste tidens försökatt minimera bränsleförbrukningen har dock lett fram till att även användandetav tryckluft har börjat ses över. Tryckluft används i dagens lastbilar av flera olika förbrukare. En viktig förbrukareav tryckluft är bromsarna som inte fungerar överhuvudtaget utan tryckluft.Tryckluften produceras av en kompressor som sitter kopplad på förbränningsmotorn.Om det finns ett läckage i tryckluftsystemet leder detta till att kompressornmåste arbeta oftare vilket i sin tur leder till en ökad bränsleförbrukning. Det finns stort intresse av att kunna detektera dessa läckage och om möjligtäven avgöra var i systemet som läckaget finns. Informationen kan sedan användasvid nästa servicetillfälle för att laga läckaget. Diagnossystemet som utvecklats i detta examensarbete bygger på modellbaseraddiagnos och använder en rekursiv implementering av minstakvadratmetodenför att skatta läckagets storlek. Resultat från validering av algoritmen visar attdiagnossystemet fungerar bra för läckage i storleksordningen 1-10 liter/minut. Deninnovativa isoleringsalgoritmen ger full felisolerbarhet för ett system med fem kretsarmen bara tre tryckgivare.

This thesis describes a novel harmonic domain approach for assessing the steady state performance of Flexible AC Transmission System (FACTS) devices. Existing harmonic analysis techniques are reviewed and used as the basis for a novel iterative harmonic domain model for PWM FACTS devices. The unified Newton formulation adopted uses a combination of positive frequency real valued harmonic and three-phase fundamental frequency power-flow mismatches to characterise a PWM converter system. A dc side mismatch formulation is employed in order to reduce the solution size, something only possible because of the hard switched nature of PWM converters. This computationally efficient formulation permits the study of generalised systems containing multiple FACTS devices. This modular PWM converter block is applied to series, shunt and multi-converter FACTS topologies, with a variety of basic control schemes. Using a three-phase power-flow initialisation and a fixed harmonic Jacobian provides robust convergence to a solution consistent with time domain simulation. By including the power-flow variables in the full harmonic solution the model avoids unnecessary assumptions regarding a fixed (or linearised) operating point, fully modelling system imbalance and the associated non-characteristic harmonics. The capability of the proposed technique is illustrated by considering a range of harmonic interaction mechanisms, both within and between FACTS devices. In particular, the impact of transmission network modelling and operating point variation is investigated with reference to ac and dc side harmonic interaction. The minor role harmonic distortion and over-modulation play in the PWM switching process is finally considered with reference to the associated reduction in system linearity.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica. / Made available in DSpace on 2012-10-22T14:42:14Z (GMT). No. of bitstreams: 1 229508.pdf: 8067955 bytes, checksum: 459c280bf1e5ed0933280e5060624868 (MD5) / Existe atualmente uma enorme variedade de equipamentos específicos cujo controlador microprocessado está embutido nos mesmos. Tais sistemas computacionais são embutidos como componentes dentro de um sistema maior. Na perspectiva da computação, tais sistemas são conhecidos como sistemas computacionais embutidos (embedded computer system), ou simplesmente sistemas embutidos (embedded systems). A grande maioria dos sistemas embutidos são programados e incluem componentes de hardware e de software. Para suportar o projeto de tais sistemas uma nova metodologia de projeto vem sendo desenvolvida denominada hardware/software co-design. Além do hardware/software co-design, é muito importante uma metodologia que leve a seleção do elemento de processamento ideal para a realização da tarefa específica do sistema embutido. O aumento de complexidade e variedade dos equipamentos com processador embutido gera a necessidade de uma abordagem interdisciplinar no processo de desenvolvimento desses equipamentos, envolvendo as áreas de engenharia de software, mecânica, elétrica e eletrônica. Neste sentido, está sendo especificada pela OMG uma linguagem de modelagem, denominada SysML (System Modelling Language), que pretende incluir em uma única especificação uma visão integrada do sistema, incluindo hardware, software e partes eletro-mecânicas. A dissertação faz um levantamento dos métodos e critérios empregados na seleção do processador a ser utilizado em um sistema embutido. As sugestões e métodos presentes na literatura são descritos, classificados e analisados. São modelados dois estudos de casos utilizando a linguagem de modelagem SysML. A partir da modelagem é realizada uma avaliação prática da atual proposta da linguagem SysML, no sentido de identificar suas capacidades e suas limitações na modelagem de sistemas embutidos, são analisados as possibilidades de extração das informações relevantes à seleção do processador embutido.