Orientador: José de Assis Fonseca Faria / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-18T02:06:39Z (GMT). No. of bitstreams: 1 Cardoso_ClaudioFernandes_D.pdf: 26277698 bytes, checksum: d17c520e85b9389e672d2641e795333d (MD5) Previous issue date: 2011 / Resumo: Esta pesquisa teve como objetivo avaliar o desempenho de um sistema asséptico piloto para a produção de leite UHT (Ultra Hight-Temperature), com capacidade de 1.000 L/h, em embalagens flexíveis institucionais do tipo Bag-in-box (BIB). As embalagens estudadas eram compostas de um filme de polietileno de baixa densidade (PEBD) e um filme de polietileno tereftalato metalizado (PETmet), com volume de 2.000 mL, desenvolvido especialmente para o envase asséptico de produtos lácteos. Leite cru refrigerado tipo A foi utilizado como matéria-prima. O envase do leite UHT foi realizado através de uma dosadeira semi-automática dentro de uma Sala Limpa ISO posicionada sobre o bocal de enchimento das embalagens. O sistema foi avaliado através da identificação e monitoramento de pontos de controle do processo, testes de esterilidade comercial, análises sensorial e físico-química do produto, bem como avaliações da embalagem. O desempenho das embalagens BIB foi avaliado através de ensaios de caracterização, integridade do sistema e estudos de estabilidade microbiana e testes de efetividade de esterilização. As embalagens foram esterilizadas com o uso de radiação ionizante (gama), com dose de 15 kGy. Os ensaios foram conduzidos através da produção de 4 lotes experimentais de leite UHT, obtido em trocador de calor a placas (140 °C por 5 s). A taxa de defeito encontrada nos testes de esterilidade comercial variou entre 0 e 6,7%, sendo que a principal causa de defeitos foi associada aos problemas inerentes a operacionalidade da linha, como falhas nas vedações das junções de tubulações e bombas centrífugas. Os resultados da avaliação dos pontos de controle do processo e embalagem indicaram um bom desempenho do sistema, justificado pela ausência de microorganismos viáveis. O leite UHT acondicionado nas embalagens BIB teve sua vida de prateleira estimada em até 27 semanas de estocagem, valor este muito superior quando comparado às amostras controle de leite UHT comercial, acondicionado em embalagens laminadas cartonadas, que teve sua vida de prateleira estimada em 19 semanas. A diferença de estabilidade físico-química, microbiológica e sensorial entre as amostras processadas e a comercial foi associada às propriedades de barreira das estruturas das embalagens à luz e ao oxigênio, bem como pela qualidade da matéria-prima utilizada. O sistema asséptico piloto avaliado correspondeu às expectativas de desempenho e atendeu aos requisitos estabelecidos pelo Codex Alimentarius. Concluiu-se que o sistema apresenta potencial para utilização por indústrias de laticínios visando atender o mercado institucional de leite longa vida / Abstract: The aim of this research was to evaluate the performance of an aseptic pilot system for the production of Ultra High Temperature (UHT) milk, with 1.000 L/h capacity, filled in flexible institutional packages Bag-in-box (BIB) type. The BIB packages were constructed with one layer of low density polyethylene film (LDPE) and another one of metalized polyethylene terephthalate film (PETmet), with 2.000 mL capacity, specially developed for the aseptic filling of dairy products. Type-A milk was used as raw material and the UHT milk filling was made by a semiautomatic machine located inside a ISO Clean room. The system was evaluated by the identification and monitoring of the control points during the process and also by commercial sterility tests, sensorial and physical-chemistry analysis and packages evaluations. The BIB packages were sterilized by gamma radiation with minimum doses of 15 kGy. The assays were conducted by the production of 4 experimental batches processed in a plate heat exchanger (140 °C/5 s). The defect rates founded were between 0 and 6.7% and these values can be explained by problems linked to the pilot plant operation, like failures in the connections of pipes and centrifugal pumps. The results of the control points evaluation and also BIB packages showed a good performance of the entire process, justified by the absence of viable microorganisms. The milk filled in BIB packages targeted until 27 weeks of shelf life, a superior value when it was compared to the commercial UHT samples, which targeted just 19 weeks. The difference of physical-chemistry, microbiology and sensory stability between the processed samples and the commercial one was associated to the oxygen and light barriers properties and also to the raw milk quality used during the processes. The pilot aseptic system evaluated attended to the Codex Alimentarius requirements and it could be concluded that the system showed potential for application in dairy industry in view of the long life milk institutional market / Doutorado / Tecnologia de Alimentos / Doutor em Tecnologia de Alimentos

Made available in DSpace on 2016-03-15T19:37:55Z (GMT). No. of bitstreams: 1 RICARDO RIBANI.pdf: 13475262 bytes, checksum: 1e8f0a623498d0aa2fda9f44449b7325 (MD5) Previous issue date: 2015-02-11 / Fundo Mackenzie de Pesquisa / With the growing amount of multimedia information, the recommender systems have become more present in digital systems. Together with the growth of the internet, more and more people have access to large multimedia collections and consequently the user is often in doubt situations when making a choice. In order to help the user to make their own choices, this research presents a study around the content-based recommender systems applied to art paintings. Here are included approaches on image retrieval algorithms, computer vision and artificial intelligence concepts such as techniques for pattern recognition. One of the goals of this research was the creation of a software for mobile phones, applied to an art paintings database. The application uses an interface developed for mobile phones, where the user can point the phone s camera to a painting and based on this painting the system generates a recommendation of another painting in the same database, considering some parameters such as style, genre or color. / Os sistemas de recomendações estão cada dia mais presentes no meio digital. Com a crescente quantidade de informações e a popularização da internet, cada vez mais as pessoas tem acesso a grandes acervos multimídia. Com isso, consequentemente o usuário se encontra muitas vezes em situações de dúvida ao fazer uma escolha. Com o objetivo de auxiliar o usuário a fazer suas escolhas, o presente trabalho apresenta um estudo em torno dos sistemas de recomendações baseados em conteúdo de imagens. Este estudo engloba uma abordagem a respeito de algoritmos de recuperação de imagens, além da aplicação de conceitos de visão computacional e inteligência artificial, como técnicas para reconhecimento de padrões. Além do estudo teórico, este trabalho teve como objetivo a criação de um sistema computacional aplicado a um banco de dados de imagens de obras de arte. Uma aplicação que utiliza uma interface desenvolvida para telefones celulares, no qual o usuário pode capturar a imagem de uma obra através da câmera do celular e baseado nessa obra o sistema gera uma recomendação de outra dentro do mesmo banco de dados, considerando parâmetros configuráveis como estilo, gênero ou cores.

Plastmaterial har sedan 1950-talet orsakat problem i naturen på grund av materialets slitstarka och svårnedbrytbara egenskaper. Dessa egenskaper är också en anledning till dess popularitet, och varje år tillförs ungefär 100 miljarder plastbärkassar bara till den europeiska marknaden. En stor del av dessa hamnar i hav och andra vattendrag där de påverkar biodiversiteten genom att plastpartiklar förtärs av marina varelser och sedan transporteras upp i näringskedjan. För att minska problemet med marin nedskräpning har Europeiska unionens medlemsstater i en gemensam ansträngning satt ett mål att till år 2025 reducera antalet plastbärkassar som förbrukas per person och år till 40 stycken. För att uppnå detta mål infördes den 1 maj i Sverige en skatt på plastbärkassar som för konsumenter innebär en prishöjning i butiker med 3 SEK per påse. Syftet med denna studie är att identifiera hur konsumenter kan förväntas svara på denna prishöjning, och vilka faktorer som förhindrar en möjlig beteendeförändring. För att få en bättre förståelse för detta intervjuades sju konsumenter från olika typer av hushåll, som ombads redogöra för sina konsumtionsrutiner och förväntade reaktion på införandet av skatten. Resultaten visade att majoriteten av informanterna trots en positiv attityd till införandet av skatten inte har för avsikt att minska den egna konsumtionen av plastbärkassar, och att den främsta anledningen till detta är de många funktioner som materialet möjliggör. / Plastic pollution has been a problem since the 1950s due to the material’s durable and persistant characteristics and slow degradability, and these characteristics are also the reason for the material’s popularity. An estimated 100 billion plastic bags are introduced to the european markets every year, with a significant amount of these ending up in oceans and other bodies of water. Plastic pollution harms biodiversity as marine species consume plastic particles which are then transported through the food chain. To counteract this problem, the European Union member states strive to limit the amount of plastic carrier bags being used to 40 per person and year, by 2025. As a means to achieve this goal, the Swedish government introduced a tax which increased the retail price of plastic carrier bags by 3 SEK as of May 1st 2020. This study aims to identify consumers intended response to this tax, and what factors might prevent a possible change of behaviour. To better understand this, seven interviews were carried out with consumers from different households, in which they were asked to share their shopping routines and expected response to the tax. The results showed that while the majority of the consumers expressed a positive attitude towards the tax, few had any intention of reducing their own consumption of the plastic carrier bag, primarily due to the many irreplacable functions provided by the material.

Tato disertační práce se zabývá vylepšením systémů pro rozpoznávání činností člověka. Současný stav vědění v této oblasti jest prezentován. Toto zahrnuje způsoby získávání digitálních obrazů a videí společně se způsoby reprezentace těchto entit za použití počítače. Dále jest prezentováno jak jsou použity extraktory příznakových vektorů a extraktory pros- torově-časových příznakových vektorů a způsoby přípravy těchto dat pro další zpracování. Příkladem následného zpracování jsou klasifikační metody. Pro zpracování se obecně obvykle používají části videa s proměnlivou délkou. Hlavní přínos této práce je vyřčená hypotéza o optimální délce analýzy video sekvence, kdy kvalita řešení je porovnatelná s řešením bez restrikce délky videosekvence. Algoritmus pro ověření této hypotézy jest navržen, implementován a otestován. Hypotéza byla experimentálně ověřena za použití tohoto algoritmu. Při hledání optimální délky bylo též dosaženo jistého zlepšení kvality klasifikace. Experimenty, výsledky a budoucí využití této práce jsou taktéž prezentovány.

The production of ferrochrome (FeCr) from chromite ore is a reducing process, whereby the Cr(III) and Fe(II) in the ore are reduced to metallic chromium (Cr) and iron (Fe) in the final product. FeCr is mostly used for the production of stainless steel, which is a vital alloy in modern society. It is, however, impossible to exclude oxygen completely from all the high temperature steps during the production process and very small amounts of Cr(VI) are therefore formed, although not intended. The formed Cr(VI) is mostly associated with the off-gas of the high temperature processes, which are cleaned before it is released into the atmosphere by means of venturi scrubbers or bag filter systems. Certain Cr(VI) species are regarded as carcinogenic, with specifically airborne exposure to these Cr(VI) species being associated with cancer of the respiratory system. FeCr smelter facilities generate three main types of waste materials, i.e. slag, venturi sludge and bag filter dust (BFD). Most of the Cr in the waste materials consists mostly of Cr(III). However, BFD generated during the cleaning of the off-gas of open/semi-closed furnaces, could contain more significant levels of Cr(VI) than the slag and sludge. The aim of this study was to determine the solubility of different Cr(VI) species present in BFDs. This would allow that the Cr(VI) in BFD is categorised as water soluble Cr(VI), sparingly soluble and insoluble Cr(VI). These solubility categories can then be related to groups of Cr(VI) compounds, therefore taking the first step in better characterisation of Cr(VI) present in BFD. Four different BFD samples from FeCr producers in South Africa were characterised in detail. Analytical methods such as scanning electron microscope (SEM), SEM with energy-dispersive X-ray spectroscopy (SEM-EDS), particle size analysis, trace metal analysis with inductively coupled plasma with a mass spectrometer detector (ICP-MS) and Cr(VI) analysis with ion chromatography (IC) were utilised in order to characterise and categorise the samples. The results indicated that more Cr(VI) leached with an increase in pH. This was in contrast with the trend for most heavy metals. This was also an indication that not only soluble, but also sparingly- and insoluble Cr(VI) compounds occur in the BFD samples evaluated. Further analysis showed that approximately one third of the Cr(VI) species was insoluble and the remainder consisted of sparingly insoluble and soluble Cr(VI) compounds. The most significant finding was that the current leaching procedures applied by FeCr producers, prior to the chemical reduction of Cr(VI), do not effectively extract the sparingly water insoluble compounds. This results in Cr(VI) leaching from waste facilities at later stages, even if seemingly effective Cr(VI) treatment was applied. Therefore, it should be considered as an extremely important future perspective to develop economically feasible Cr(VI) extraction procedures that will ensure complete extraction of sparing water soluble Cr(VI) compounds together with the water soluble fraction, prior to chemical reduction of Cr(VI) and subsequent storage of the residue on a waste facility. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015

The production of ferrochrome (FeCr) from chromite ore is a reducing process, whereby the Cr(III) and Fe(II) in the ore are reduced to metallic chromium (Cr) and iron (Fe) in the final product. FeCr is mostly used for the production of stainless steel, which is a vital alloy in modern society. It is, however, impossible to exclude oxygen completely from all the high temperature steps during the production process and very small amounts of Cr(VI) are therefore formed, although not intended. The formed Cr(VI) is mostly associated with the off-gas of the high temperature processes, which are cleaned before it is released into the atmosphere by means of venturi scrubbers or bag filter systems. Certain Cr(VI) species are regarded as carcinogenic, with specifically airborne exposure to these Cr(VI) species being associated with cancer of the respiratory system. FeCr smelter facilities generate three main types of waste materials, i.e. slag, venturi sludge and bag filter dust (BFD). Most of the Cr in the waste materials consists mostly of Cr(III). However, BFD generated during the cleaning of the off-gas of open/semi-closed furnaces, could contain more significant levels of Cr(VI) than the slag and sludge. The aim of this study was to determine the solubility of different Cr(VI) species present in BFDs. This would allow that the Cr(VI) in BFD is categorised as water soluble Cr(VI), sparingly soluble and insoluble Cr(VI). These solubility categories can then be related to groups of Cr(VI) compounds, therefore taking the first step in better characterisation of Cr(VI) present in BFD. Four different BFD samples from FeCr producers in South Africa were characterised in detail. Analytical methods such as scanning electron microscope (SEM), SEM with energy-dispersive X-ray spectroscopy (SEM-EDS), particle size analysis, trace metal analysis with inductively coupled plasma with a mass spectrometer detector (ICP-MS) and Cr(VI) analysis with ion chromatography (IC) were utilised in order to characterise and categorise the samples. The results indicated that more Cr(VI) leached with an increase in pH. This was in contrast with the trend for most heavy metals. This was also an indication that not only soluble, but also sparingly- and insoluble Cr(VI) compounds occur in the BFD samples evaluated. Further analysis showed that approximately one third of the Cr(VI) species was insoluble and the remainder consisted of sparingly insoluble and soluble Cr(VI) compounds. The most significant finding was that the current leaching procedures applied by FeCr producers, prior to the chemical reduction of Cr(VI), do not effectively extract the sparingly water insoluble compounds. This results in Cr(VI) leaching from waste facilities at later stages, even if seemingly effective Cr(VI) treatment was applied. Therefore, it should be considered as an extremely important future perspective to develop economically feasible Cr(VI) extraction procedures that will ensure complete extraction of sparing water soluble Cr(VI) compounds together with the water soluble fraction, prior to chemical reduction of Cr(VI) and subsequent storage of the residue on a waste facility. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015

Robust long-term positioning for autonomous mobile robots is essential for many applications. In many environments this task is challenging, as errors accumulate in the robot’s position estimate over time. The robot must also build a map so that these errors can be corrected when mapped regions are re-visited; this is known as Simultaneous Localisation and Mapping, or SLAM. Successful SLAM schemes have been demonstrated which accurately map tracks of tens of kilometres, however these schemes rely on expensive sensors such as laser scanners and inertial measurement units. A more attractive, low-cost sensor is a digital camera, which captures images that can be used to recognise where the robot is, and to incrementally position the robot as it moves. SLAM using a single camera is challenging however, and many contemporary schemes suffer complete failure in dynamic or featureless environments, or during erratic camera motion. An additional problem, known as scale drift, is that cameras do not directly measure the scale of the environment, and errors in relative scale accumulate over time, introducing errors into the robot’s speed and position estimates. Key to a successful visual SLAM system is the ability to continue operation despite these difficulties, and to recover from positioning failure when it occurs. This thesis describes the development of such a scheme, which is known as BoWSLAM. BoWSLAM enables a robot to reliably navigate and map previously unknown environments, in real-time, using only a single camera. In order to position a camera in visually challenging environments, BoWSLAM combines contemporary visual SLAM techniques with four new components. Firstly, a new Bag-of-Words (BoW) scheme is developed, which allows a robot to recognise places it has visited previously, without any prior knowledge of its environment. This BoW scheme is also used to select the best set of frames to reconstruct positions from, and to find efficient wide-baseline correspondences between many pairs of frames. Secondly, BaySAC, a new outlier- robust relative pose estimation scheme based on the popular RANSAC framework, is developed. BaySAC allows the efficient computation of multiple position hypotheses for each frame. Thirdly, a graph-based representation of these position hypotheses is proposed, which enables the selection of only reliable position estimates in the presence of gross outliers. Fourthly, as the robot explores, objects in the world are recognised and measured. These measurements enable scale drift to be corrected. BoWSLAM is demonstrated mapping a 25 minute 2.5km trajectory through a challenging and dynamic outdoor environment in real-time, and without any other sensor input; considerably further than previous single camera SLAM schemes.

<p>The conventional mechanism of fermion mass generation in the Standard Model involves Spontaneous Symmetry Breaking (SSB). In this thesis, we study an alternate mechanism for the generation of fermion masses that does not require SSB, in the context of lattice field theories. Being inherently strongly coupled, this mechanism requires a non-perturbative approach like the lattice approach.</p><p>In order to explore this mechanism, we study a simple lattice model with a four-fermion interaction that has massless fermions at weak couplings and massive fermions at strong couplings, but without any spontaneous symmetry breaking. Prior work on this type of mass generation mechanism in 4D, was done long ago using either mean-field theory or Monte-Carlo calculations on small lattices. In this thesis, we have developed a new computational approach that enables us to perform large scale quantum Monte-Carlo calculations to study the phase structure of this theory. In 4D, our results confirm prior results, but differ in some quantitative details of the phase diagram. In contrast, in 3D, we discover a new second order critical point using calculations on lattices up to size $ 60^3$. Such large scale calculations are unprecedented. The presence of the critical point implies the existence of an alternate mechanism of fermion mass generation without any SSB, that could be of interest in continuum quantum field theory.</p> / Dissertation

A photograph typically depicts an aspect of the real world, such as an outdoor landscape, a portrait, or an event. The task of creating abstract digital representations of images has received a great deal of attention in the computer vision literature because it is rarely useful to work directly with the raw pixel data. The challenge of working with raw pixel data is that small changes in lighting can result in different digital images, which is not typically useful for downstream tasks such as object detection. One approach to representing an image is automatically extracting and quantising visual features to create a bag-of-terms vector. The bag-of-terms vector helps overcome the problems with raw pixel data but this unstructured representation discards potentially useful information about the spatial and semantic relationships between the parts of the image. The central argument of this thesis is that capturing and encoding the relationships between parts of an image will improve the performance of extrinsic tasks, such as image description or search. We explore this claim in the restricted domain of images representing events, such as riding a bicycle or using a computer. The first major contribution of this thesis is the Visual Dependency Representation: a novel structured representation that captures the prominent region–region relationships in an image. The key idea is that images depicting the same events are likely to have similar spatial relationships between the regions contributing to the event. This representation is inspired by dependency syntax for natural language, which directly captures the relationships between the words in a sentence. We also contribute a data set of images annotated with multiple human-written descriptions, labelled image regions, and gold-standard Visual Dependency Representations, and explain how the gold-standard representations can be constructed by trained human annotators. The second major contribution of this thesis is an approach to automatically predicting Visual Dependency Representations using a graph-based statistical dependency parser. A dependency parser is typically used in Natural Language Processing to automatically predict the dependency structure of a sentence. In this thesis we use a dependency parser to predict the Visual Dependency Representation of an image because we are working with a discrete image representation – that of image regions. Our approach can exploit features from the region annotations and the description to predict the relationships between objects in an image. In a series of experiments using gold-standard region annotations, we report significant improvements in labelled and unlabelled directed attachment accuracy over a baseline that assumes there are no relationships between objects in an image. Finally, we find significant improvements in two extrinsic tasks when we represent images as Visual Dependency Representations predicted from gold-standard region annotations. In an image description task, we show significant improvements in automatic evaluation measures and human judgements compared to state-of-the-art models that use either external text corpora or region proximity to guide the generation process. In the query-by-example image retrieval task, we show a significant improvement in Mean Average Precision and the precision of the top 10 images compared to a bag-of-terms approach. We also perform a correlation analysis of human judgements against automatic evaluation measures for the image description task. The automatic measures are standard measures adopted from the machine translation and summarization literature. The main finding of the analysis is that unigram BLEU is less correlated with human judgements than Smoothed BLEU, Meteor, or skip-bigram ROUGE.

The aim of this thesis was to assess the quality of preserved forage in various ways of preserving silage. Sensory evaluation of the fermentation process and laboratory evaluation was used to assess the quality of legume-based silages in various preservation technologies. In addition, forage preservation in silage pressing technology was compared with and without additive (Silafor 2000 Plus). The literature review shows the importance of feed conservation, basic methods of conservation of forage, botanical composition of forage crops, conservation principles and their processes. The following are the advantages and disadvantages of preservation processes. In total, 3 ways of preservation of legume-free mixture - baling of foil, silage trough and silage bag - were evaluated. The evaluation of the results of the technology was based on the best results of the method of preservation in the bag, the preservation in the pit, the package using adiditive and the lower quality preservation of the package without additive. The forage quality was also significantly influenced by the proportion of oats in the mixture and the phenophase of the harvest.