Made available in DSpace on 2014-10-09T12:51:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:16Z (GMT). No. of bitstreams: 1 11305.pdf: 5835688 bytes, checksum: 8900e9fd0579d9e4e1a656b613567be9 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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Made available in DSpace on 2014-10-09T12:51:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:43Z (GMT). No. of bitstreams: 0 / Vazamentos em tubos pressurizados geram ondas acústicas que se propagam através das paredes destes tubos, as quais podem ser captadas por acelerômetros ou por sensores de emissão acústica. O conhecimento de como estas paredes podem vibrar, ou de outro modo como as ondas acústicas se propagam neste meio, é fundamental em um processo de detecção e localização da fonte de vazamento. Neste trabalho, foi implementado um modelo analítico, através das equações de movimento da casca cilíndrica, com o objetivo de entender o comportamento da superfície do tubo em função de uma excitação pontual. Como a superfície cilíndrica é um meio fechado na direção circunferencial, ondas que iniciaram sua jornada, a partir de uma fonte pontual sobre a superfície, se encontrarão com outras que já completaram a volta na casca cilíndrica, tanto no sentido horário como no anti-horário, gerando interferências construtivas e destrutivas. Após um tempo suficiente, uma estacionariedade é atingida, criando pontos de picos e vales na superfície da casca, os quais podem ser visualizadas através de uma representação gráfica do modelo analítico criado. Os resultados teóricos foram comprovados através de medidas realizadas em uma bancada de testes composta de um tubo de aço terminado em caixa de areia, simulando a condição de tubo infinito. Para proceder à localização da fonte pontual sobre a superfície, adotou-se o processo de solução inversa, ou seja, conhecidos os sinais dos sensores dispostos na superfície do tubo, determina-se através do modelo teórico onde a fonte que gerou estes sinais pode estar. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:51:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:16Z (GMT). No. of bitstreams: 1 11305.pdf: 5835688 bytes, checksum: 8900e9fd0579d9e4e1a656b613567be9 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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O controle de perdas em sistemas de distribuição de água para abastecimento é uma preocupação constante, e uma tarefa fundamental para a solução do problema é a detecção rápida e confiável dos vazamentos que frequentemente iniciam em qualquer ponto da rede. Uma abordagem promissória é a detecção de vazamentos baseada na análise de sinais adquiridos pelo monitoramento das redes durante sua operação, e dentro dela se enquadra este trabalho. É desenvolvido um sistema de reconhecimento de padrões para análise de sinais de pressão e vazão que permite identificar se durante a aquisição do sinal aconteceu um vazamento ou não. Para a conformação desse sistema diversas técnicas são exploradas, incluindo a extração de características no domínio do tempo (energia, entropia, número de cruzamentos por zero) e na decomposição wavelet (distribuição da energia nas componentes). Também é explorado o uso de algoritmos para classificação de diferentes tipos (vizinhos mais próximos, árvore de decisão, regra de decisão, Naive Bayes, máquina de vetor suporte e rede neural artificial com funções de base radial). Sinais são adquiridos junto ao circuito hidráulico experimental, que permitiu a simulação da ocorrência de um vazamento na rede, para constituir uma amplia base de dados com sinais de exemplo. Além da revisão bibliográfica e os conceitos relativos às metodologias exploradas, são apresentadas neste documento as análises que conduzem à criação do sistema de reconhecimento de padrões mais apropriado para o problema. Das análises dos diferentes métodos considerados é definido o sistema de reconhecimento de padrões, em suas etapas de segmentação e padronização, extração de características e classificação. A avaliação do sistema proposto mostra um desempenho totalmente satisfatório, com reconhecimento acertado de sinais vinculados ou não a um vazamento em mais de 95% dos testes. / Control of losses in water supply systems is a constant concern, and a key to the solution of this problem is the rapid and reliable detection of leaks that often begin anywhere on the network. A promising approach to solve the problem is the leak detection based on the analysis of signals acquired by monitoring the network in operation, and this research fits with that approach. Its developed a pattern recognition system for the analysis of pressure and flow signals, which identifies whether a leak happened during signal acquisition. Several techniques are exploited for forming this system, including the feature extraction in the time domain (energy, entropy, zero crossings count) and in the wavelet decomposition (energy distribution in the components). Also, the use of different types of algorithms for classification (nearest neighbors, decision tree, decision rule, Naive Bayes, support vector machine and artificial neural network with radial basis functions) is explored. Signals are acquired from the experimental hydraulic circuit, allowing the simulation of the onset of a leak in the network, to form a big database of example signals. Besides the literature review and the concepts relating to the considered methods, in this document are shown the analyses leading to the creation of the pattern recognition system most appropriate for the problem. The analysis of the methods considered allows defining the pattern recognition system, which is composed by segmentation and standardization, feature extraction and classification. The evaluation of the proposed system shows a completely satisfactory performance, recognizing rightly the signals as linked or not to a leak in more than 95% of the tests.

LL.M. (International Law) / Before 2006, there had been some movement to expose conspiracy and injustices in government and corporate life but the emergence of Julian Assange and wikileaks would set a new standard in this kind of investigative probe into what the political leaders and heads of major corporations did behind the scenes. Assange’s initial revelations and release of incriminating documents was about to launch his debut as an ‘international man of mystery’ as people who are globally and politically curious will forever wonder what else he would reveal to the world. The first target of his disclosures was Africa then the United States but his actions would unleash a wave of leaks with corporate and government conspiracy at a volume that the world as we know it was previously unaccustomed to. Although some doubted the authenticity of his disclosures, and others criticized his methods, none doubted his right to freedom of expression as enshrined in national, regional and international instruments. Assange’s organization proposes that governments and corporations should be transparent in their dealings, and policies. Although tumultuous at first, leaks from Assange have helped expose some corrupt practices that would not otherwise have come to light. The impact of wikileaks on freedom of expression in the world has been massive and far reaching, the viral way in which the leaks spread are evidence to the fact that people have always been curious about this kind of conspiracy theories and are eager for transparency. It shows also that it is unwise to underestimate the impact that an event in one country could trigger globally. But what does it really mean to global stability and freedom of expression when one man chooses to go against conventional methods and probe into the powers that be? How will this change how the world does business in the area of what people are allowed to freely say or disclose without persecution and how this disclosure affect the laws that govern this kind of freedom of expression?

Excessive memory use may cause severe performance problems and system crashes. Without appropriate tools, it may be difficult or impossible to determine why a program is using too much memory. This applies even though Python provides automatic memory management --- garbage collection can help avoid many memory allocation bugs, but only to a certain extent due to the lack of information during program execution. There is still a need for tools helping the programmer to understand the memory behaviour of programs, especially in complicated situations. The primary motivation for Heapy is that there has been a lack of such tools for Python. The main questions addressed by Heapy are how much memory is used by objects, what are the objects of most interest for optimization purposes, and why are objects kept in memory. Memory leaks are often of special interest and may be found by comparing snapshots of the heap population taken at different times. Memory profiles, using different kinds of classifiers that may include retainer information, can provide quick overviews revealing optimization possibilities not thought of beforehand. Reference patterns and shortest reference paths provide different perspectives of object access patterns to help explain why objects are kept in memory.

<p>Compressed  air  is  a  powerful  source  of  stored  energy  and  is  used  in  a  variety  of  applications varying from painting to pressing, making it a versatile tool for manufacturers.  Due to the high cost and energy consumption associated with producing compressed air and it’s use within industrial manufacturing, it is often referred to as a fourth utility behind electricity, natural gas, and water.  This is the reason why air compressors and associated equipment are often the focus for improvements in the eyes of manufacturing plant managers.</p> <p><br></p> <p>As compressed air can be used in multiple ways, the methods used to extract and transfer the energy from this source vary as well.  Compressed air can flow through different types of piping, such as aluminum, Polyvinyl Chloride (PVC), rubber, etc.  with varying hydraulic diameters, and through different fittings such as 90-degree elbows, T-junctions, valves, etc.which can cause one of the major concerns related to managing the energy consumption of an air compressor, and that is the waste of air through leaks.</p> <p>Air leaks make up a considerable portion of the energy that is wasted in a compressed air system,  as they cause a multitude of problems that the compressor will have to makeup  for  to  maintain  the  steady  operation  of  the  pneumatic  devices  on  the  manufacturing floor that rely on compressed air for their application.  When air leaks are formed within the compressed air piping network,  they act as continuous consumers and cause not only the siphoning off of said compressed air, put also reduce the pressure that is needed within the  pipes.   The  air  compressors  will  have  to  work  harder  to  compensate  for  the  losses  in the pressure and the amount of air itself, causing an over consumption of energy and power.Overworking the air compressor also causes the internal equipment to be stretched beyond its capabilities, especially if they are already running at full loads, reducing their total lifespans considerably.  In addition, if there are multiple leaks close to the pneumatic devices on the manufacturing floor, the immediate loss in pressure and air can cause the devices to operate inefficiently and thus cause a reduction in production.  This will all cumulatively impact the manufacturer considerably when it comes to energy consumption and profits.</p> <p>There are multiple methods of air leak detection and accounting that currently exist so as  to  understand  their  impact  on  the  compressed  air  systems.   The  methods  are  usually conducted when the air compressors are running but during the time when there is no, orminimal, active consumption of the air by the pneumatic devices on the manufacturing floor.This time period is usually called non-production hours and generally occur during breaksor  between  employee  shift  changes.   This  time  is  specifically  chosen  so  that  the  only  air consumption within the piping is that of the leaks and thus, the majority of the energy and power consumed during this time is noted to be used to feed the air leaks.  The collected data is then used to extrapolate and calculate the energy and power consumed by these leaks for the rest of the year.  There are, however, a few problems that arise when using such a method to understand the effects of the leaks in the system throughout the year.  One of the issues is that it is assumed that the air and pressure lost through the found leaks areconstant even during the production hours i.e.  the hours that there is active air consumptionby the pneumatic devices on the floor, which may not be the case due to the increased airflow rates and varying pressure within the line which can cause an increase in the amount of air lost through the same orifices that was initially detected.  Another challenge that arises with using only the data collected during a single non-production time period is that theremay be additional air leaks that may be created later on,  and the energy and power lostdue to the newer air leaks would remain unaccounted for.  As the initial estimates will not include the additional losses, the effects of the air leaks may be underestimated by the plant managers.  To combat said issues, a continuous method of air leak analyses will be required so as to monitor the air compressors’ efficiency in relation to the air leaks in real time.</p> <p>By studying a model that includes both the production, and non-production hours when accounting  for  the  leaks,  it  was  observed  that  there  was  a  50.33%  increase  in  the  energy losses, and a 82.90% increase in the demand losses that were estimated when the effects ofthe air leaks were observed continuously and in real time.  A real time monitoring system canprovide an in-depth understanding of the compressed air system and its efficiency.  Managing leaks within a compressed air system can be challenging especially when the amount of energy wasted through these leaks are unaccounted for.  The main goal of this research was to finda non intrusive way to calculate the amount of air as well as energy lost due to these leaks using time series pressure measurements.  Previous studies have shown a strong relationship between the pressure difference, and the use of air within pneumatic lines, this correlationalong with other factors has been exploited in this research to find a novel and viable methodof leak accounting to develop a Continuous Air Leak Monitoring (CALM) system.</p> <p><br></p>