861 resultados para POWER QUALITY AND POWER SYSTEM RESTORATION
Resumo:
It is usual to hear a strange short sentence: «Random is better than...». Why is randomness a good solution to a certain engineering problem? There are many possible answers, and all of them are related to the considered topic. In this thesis I will discuss about two crucial topics that take advantage by randomizing some waveforms involved in signals manipulations. In particular, advantages are guaranteed by shaping the second order statistic of antipodal sequences involved in an intermediate signal processing stages. The first topic is in the area of analog-to-digital conversion, and it is named Compressive Sensing (CS). CS is a novel paradigm in signal processing that tries to merge signal acquisition and compression at the same time. Consequently it allows to direct acquire a signal in a compressed form. In this thesis, after an ample description of the CS methodology and its related architectures, I will present a new approach that tries to achieve high compression by design the second order statistics of a set of additional waveforms involved in the signal acquisition/compression stage. The second topic addressed in this thesis is in the area of communication system, in particular I focused the attention on ultra-wideband (UWB) systems. An option to produce and decode UWB signals is direct-sequence spreading with multiple access based on code division (DS-CDMA). Focusing on this methodology, I will address the coexistence of a DS-CDMA system with a narrowband interferer. To do so, I minimize the joint effect of both multiple access (MAI) and narrowband (NBI) interference on a simple matched filter receiver. I will show that, when spreading sequence statistical properties are suitably designed, performance improvements are possible with respect to a system exploiting chaos-based sequences minimizing MAI only.
Resumo:
Nowadays it is requested more investigations on alternative rearing systems that are able to improve poultry welfare and to warrant high-quality and safe meat products. This thesis work was focused on the evaluation of the oxidative stability of poultry meats, obtained with different rearing systems, diets (supplemented with bioactive compounds), and packaging conditions. The thesis work was divided into the following parts: - Evaluation of the effects of different rearing systems on the quality, fatty acid composition and oxidative stability of poultry thigh and breast meat belonging to different product categories (“rotisserie” and “cut-up” carcasses); - Evaluation of the effects of different rearing systems and packaging conditions on the shelf-life of poultry thigh meat stored at 4°C for 14 days, and the effects of feed supplementation with thymol (control diet and diet with 2 different concentration of thymol) and packaging conditions on lipid oxidation of poultry thigh meat shelf-life (stored at 4°C for 14 days). The oxidative stability of poultry meat was studied by means of the spectrophotometric determinations of peroxide value and thiobarbituric acid reactive substances. - Evaluation of anti-inflammatory effects of different flavonoids (thymol, luteolin, tangeretin, sulforaphane, polymethoxyflavones, curcumin derivates) to detect their biological activity in LPS-stimulated RAW 264.7 macrophage cells in vitro, in order to study more in depth their action mechanisms. It was evaluated the cell vitality (MTT assay), nitrite concentration and protein profile. The study was focused on the identification of potential dietary bioactive compounds in order to investigate their biological activity and possible synergic effects, and to develop new suitable strategies for long-term promotion of human health, in particular against cancer.
Resumo:
One of the current trends in governance and legal development in Russia is aimed at establishing a modern, efficient and internationally harmonised system of safeguards of human rights and civil liberties. A fairly recent addition to this system has been the institution of ombudsman as a public authority specialised in promoting and protecting human rights and civil liberties. The introduction of this institution as well as its formalisation at the constitutional and legislative levels has been increasingly relevant and important, as it raises the dealings between the state and the individual to a new level. As an independent public institution resolving conflicts between citizens and government authorities, the ombudsman makes steps, within the scope of his jurisdiction, to restitute individual rights, and helps to enhance the reputation of government. The present work describes and assesses the birth, development and institutionalization process of the Ombudsman Office in the Russian Federation, at federal and regional levels, with a particular emphasis on the role of international references and cooperation for institution building. Ombudsmen have done a magnificent job in demonstrating value with the resolution of individual and systemic complaints; subsequent improvements to government; and economic savings by mitigating litigation costs.
Resumo:
Die Molekularbiologie von Menschen ist ein hochkomplexes und vielfältiges Themengebiet, in dem in vielen Bereichen geforscht wird. Der Fokus liegt hier insbesondere auf den Bereichen der Genomik, Proteomik, Transkriptomik und Metabolomik, und Jahre der Forschung haben große Mengen an wertvollen Daten zusammengetragen. Diese Ansammlung wächst stetig und auch für die Zukunft ist keine Stagnation absehbar. Mittlerweile aber hat diese permanente Informationsflut wertvolles Wissen in unüberschaubaren, digitalen Datenbergen begraben und das Sammeln von forschungsspezifischen und zuverlässigen Informationen zu einer großen Herausforderung werden lassen. Die in dieser Dissertation präsentierte Arbeit hat ein umfassendes Kompendium von humanen Geweben für biomedizinische Analysen generiert. Es trägt den Namen medicalgenomics.org und hat diverse biomedizinische Probleme auf der Suche nach spezifischem Wissen in zahlreichen Datenbanken gelöst. Das Kompendium ist das erste seiner Art und sein gewonnenes Wissen wird Wissenschaftlern helfen, einen besseren systematischen Überblick über spezifische Gene oder funktionaler Profile, mit Sicht auf Regulation sowie pathologische und physiologische Bedingungen, zu bekommen. Darüber hinaus ermöglichen verschiedene Abfragemethoden eine effiziente Analyse von signalgebenden Ereignissen, metabolischen Stoffwechselwegen sowie das Studieren der Gene auf der Expressionsebene. Die gesamte Vielfalt dieser Abfrageoptionen ermöglicht den Wissenschaftlern hoch spezialisierte, genetische Straßenkarten zu erstellen, mit deren Hilfe zukünftige Experimente genauer geplant werden können. Infolgedessen können wertvolle Ressourcen und Zeit eingespart werden, bei steigenden Erfolgsaussichten. Des Weiteren kann das umfassende Wissen des Kompendiums genutzt werden, um biomedizinische Hypothesen zu generieren und zu überprüfen.
Resumo:
To assess the diagnostic accuracy, image quality, and radiation dose of an iterative reconstruction algorithm compared with a filtered back projection (FBP) algorithm for abdominal computed tomography (CT) at different tube voltages.
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To intraindividually compare a low-tube-voltage (80 kVp), high-tube-current (675 mA) computed tomographic (CT) technique with a high-tube-voltage (140 kVp) CT protocol for the detection of pancreatic tumors, image quality, and radiation dose during the pancreatic parenchymal phase.
Resumo:
To investigate whether an adaptive statistical iterative reconstruction (ASIR) algorithm improves the image quality at low-tube-voltage (80-kVp), high-tube-current (675-mA) multidetector abdominal computed tomography (CT) during the late hepatic arterial phase.
Resumo:
The effect of copper (Cu) filtration on image quality and dose in different digital X-ray systems was investigated. Two computed radiography systems and one digital radiography detector were used. Three different polymethylmethacrylate blocks simulated the pediatric body. The effect of Cu filters of 0.1, 0.2, and 0.3 mm thickness on the entrance surface dose (ESD) and the corresponding effective doses (EDs) were measured at tube voltages of 60, 66, and 73 kV. Image quality was evaluated in a contrast-detail phantom with an automated analyzer software. Cu filters of 0.1, 0.2, and 0.3 mm thickness decreased the ESD by 25-32%, 32-39%, and 40-44%, respectively, the ranges depending on the respective tube voltages. There was no consistent decline in image quality due to increasing Cu filtration. The estimated ED of anterior-posterior (AP) chest projections was reduced by up to 23%. No relevant reduction in the ED was noted in AP radiographs of the abdomen and pelvis or in posterior-anterior radiographs of the chest. Cu filtration reduces the ESD, but generally does not reduce the effective dose. Cu filters can help protect radiosensitive superficial organs, such as the mammary glands in AP chest projections.
Resumo:
Early intervention can help to reduce the burden of disability in the older population, but many do not access preventive care. There is uncertainty over what factors influence case finding in older patients in general practice.
Digital signal processing and digital system design using discrete cosine transform [student course]
Resumo:
The discrete cosine transform (DCT) is an important functional block for image processing applications. The implementation of a DCT has been viewed as a specialized research task. We apply a micro-architecture based methodology to the hardware implementation of an efficient DCT algorithm in a digital design course. Several circuit optimization and design space exploration techniques at the register-transfer and logic levels are introduced in class for generating the final design. The students not only learn how the algorithm can be implemented, but also receive insights about how other signal processing algorithms can be translated into a hardware implementation. Since signal processing has very broad applications, the study and implementation of an extensively used signal processing algorithm in a digital design course significantly enhances the learning experience in both digital signal processing and digital design areas for the students.
Resumo:
In this study I will endeavor to show that the American system of health care violates any conception of distributive justice understood as equality of opportunity. This system fails to provide equal access through a lack of universal insurance, a consumer driven conception of quality, and a system wide focus on cost control, leaving millions of Americans exposed to the ravages of disease. However, if health is understood as an antecedent for one's ability to function across a number of categories that have been objectively deemed as vital to engage in a life that is fully human than the commitment our nation has to the protection of fair equality of opportunity, established by our adoption of a Rawlsian conception of justice, necessitates a revision of our nation's conception of quality to encapsulate health outcomes as well as the advent of a system of universal coverage. Quality care will come to be understood as care that returns to the patient the ability to function across those categories of functioning that illness has jeopardized, and this conception of quality will precipitate system wide reform geared at the creation of positive health outcomes. This paper will articulate this argument by reconstructing and synthesizing precepts from the contemporary philosophical sources and then applying these to the practical workings of our healthcare system, while concurrently demonstrating that a system of distributive justice is compatible with the creation of a universal system of healthcare.