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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Padrões de comportamentos de risco e proteção relacionados a doenças crônicas não transmissíveis entre adolescentes brasileiros / Patterns of risk and protective behaviors related to non-communicable diseases among Brazilian adolescents

Ricardo, Camila Zancheta 29 June 2017 (has links)
Introdução: Um pequeno grupo de fatores de risco modificáveis é responsável por grande parte da mortalidade e morbidade devidas a doenças crônicas não transmissíveis (DCNT). Esses comportamentos de risco, frequentemente, se originam na adolescência e se mantêm na vida adulta, com consequências a curto, médio e longo prazo. Atualmente, além de determinar a prevalência de cada um dos fatores de risco, destaca-se a importância de avaliar como eles se agrupam na população, pois alguns desses comportamentos podem interagir entre si, produzindo um risco ainda maior do que a soma de riscos individuais. Objetivos: Identificar padrões de comportamentos de risco e proteção relacionados a doenças crônicas entre adolescentes brasileiros e verificar sua associação com características socioeconômicas e demográficas; avaliar a coocorrência de múltiplos fatores de risco entre os adolescentes, identificar agrupamentos e verificar a associação do acúmulo de riscos com características da população. Método: A fonte de dados utilizada foi a Pesquisa Nacional de Saúde do Escolar 2012, que coletou informações sobre saúde de adolescentes por meio de questionário autoaplicável em amostra representativa de alunos matriculados no 9º ano do ensino fundamental de escolas públicas e privadas brasileiras. Foram utilizadas informações sobre alimentação, atividade física, tabagismo, consumo de álcool e características socioeconômicas e demográficas. A análise fatorial foi usada para identificar padrões de comportamento a partir de uma lista de fatores de risco e proteção para DCNT. A associação entre os padrões encontrados e as características dos estudantes foi avaliada com modelos de regressão linear. A coocorrência de múltiplos fatores de risco foi avaliada com um escore correspondente à soma de cinco comportamentos: 1) Consumo infrequente de frutas e hortaliças, 2) Consumo frequente de alimentos ultraprocessados; 3) Atividade física insuficiente; 4) Fumo; e 5) Consumo abusivo de álcool. Os agrupamentos foram identificados utilizando a razão entre a prevalência observada e a prevalência esperada (O/E) para cada uma das 32 combinações de fatores de risco possíveis. As razões de prevalência O/E maiores que um foram indicativas de um agrupamento (ou cluster). A associação entre o acúmulo de quatro ou cinco dos fatores de risco e as variáveis socioeconômicas e demográficas foi avaliada com a utilização de modelo de regressão logística. Resultados: Foram encontrados quatro padrões de comportamentos: \"alimentação não saudável\", \"alimentação saudável\", \"atividade física\" e \"álcool e cigarro\". De forma geral, os grupos que apresentaram pior perfil de adesão aos padrões comportamentais encontrados foram: meninas, adolescentes mais velhos, e aqueles que não viviam com a mãe e o pai. Em relação à ocorrência simultânea dos fatores de risco definidos, apenas 2,5% dos adolescentes não apresentou nenhum dos comportamentos, enquanto 38,1% acumulou dois, 34,2%, três, 8,9%, quatro e 1,5%, os cinco fatores de risco estudados. As combinações de comportamentos mais comuns nos adolescentes foram aquelas em que estavam presentes os fatores de risco relacionados a alimentação e atividade física, ainda que as razões O/E fossem próximas a um. As maiores razões O/E foram encontradas para as combinações em que estavam presentes o cigarro e o álcool, indicando a forte correlação entre o uso das duas substâncias, ainda que a prevalência seja baixa nessa faixa etária. As características associadas ao acúmulo de quatro ou cinco fatores de risco foram: sexo feminino, ter mais de 16 anos, não viver com a mãe e o pai, menor escolaridade da mãe, ser aluno de escola pública, viver em municípios que sejam capitais de estado e nas regiões mais desenvolvidas do país. Conclusão: Os comportamentos de risco relacionados a alimentação e atividade física são os mais frequentes e se distribuem de forma independente nessa faixa etária. Por outro lado, o uso de cigarro e álcool é bastante correlacionado, apesar da baixa prevalência. A presença de múltiplos fatores de risco é comum nessa população e a identificação de grupos mais vulneráveis pode auxiliar no direcionamento de estratégias de promoção à saúde e prevenção de agravos relacionadas ao controle de DCNT ainda durante a adolescência / Introduction: A small group of modifiable risk factors accounts for most of the disease burden and mortality due to non-communicable diseases (NCD). These risk behaviors frequently originate in adolescence and remain in adulthood with short-, medium- and long-term consequences. Currently, in addition to determining the prevalence of each of the risk factors, it is important to evaluate how they cluster among the population, since some of these behaviors might interact with each other, producing an even greater risk than the sheer sum of individual risks. Objectives: To identify patterns of risk and protection behaviors related to chronic diseases among Brazilian adolescents and to verify their association with socioeconomic and demographic characteristics; And to assess the co-occurrence of multiple risk factors among adolescents, to investigate the clustering of risk factors, and to verify the association of presence of multiple risk factors with population characteristics. Methods: Our data source was the Brazilian National Survey of School Health (Pesquisa Nacional de Saúde do Escolar - PeNSE) 2012, which collected data on adolescent health through a self-administered questionnaire in a representative sample of students enrolled in the 9th grade of elementary education in public and private Brazilian schools. We used data about diet, physical activity, smoking, alcohol consumption, socioeconomic and demographic characteristics. Factor analysis was used to identify patterns of behavior from a list of risk and protective factors for NCD. The association between the identified patterns and students\' characteristics was evaluated using linear regression models. The co-occurrence of multiple risk factors was evaluated with a score corresponding to the sum of five behaviors: 1) Infrequent consumption of fruits and vegetables, 2) Frequent consumption of ultraprocessed foods; 3) Insufficient physical activity; 4) Smoke; and 5) Abuse of alcohol. The clustering was identified using the ratio between the observed and expected prevalence (O/E) for each of the 32 combinations of risk factors. Observed/expected ratios (O/E) higher than 1 were considered an indicative of clustering. The association between the prevalence of four or five risk factors and the socioeconomic and demographic variables was evaluated using a logistic regression model. Results: Four patterns of behavior were found: \"unhealthy diet\", \"healthy diet\", \"physical activity\" and \"alcohol and cigarette use\". In general, the groups that presented the worst profile of adherence to the behavioral patterns found were: girls, older adolescents, and those who did not live with the mother and the father. Regarding the simultaneous occurrence of defined risk factors, only 2.5% of adolescents did not present any of the behaviors, while 38.1% accumulated two, 34.2%, three, 8.9%, four and 1.5% all of risk factors analyzed. The most common combinations of behaviors in adolescents were those in which risk factors related to diet and physical activity were present, even though O/E ratios were close to one. The highest O/E ratios were found for the combination of cigarette and alcohol, suggesting a strong correlation between the use of both substances, although the prevalence is low in this age group. The characteristics associated with the presence of four or five risk factors were: female, being over 16 years old, not living with the mother and father, lower education of the mother, being a public school student, living in capitals, and living in the more developed regions of the country. Conclusion: The risk behaviors related to diet and physical activity are the most frequent and occur independently in this age group. On the other hand, cigarette and alcohol use is highly correlated, despite the low prevalence. The presence of multiple risk factors is common in this population and the identification of more vulnerable groups can support strategies for health promotion and prevention of diseases related to the control of CNCD even during adolescence
52

O tamanduá-bandeira (Myrmecophaga tridactyla) em áreas protegidas e seus entornos no Cerrado do nordeste do estado de São Paulo / The giant anteater (Myrmecophaga tridactyla) in protected areas and its surroundings in Cerrado of São Paulo state.

Versiani, Natália Fraguas 03 June 2016 (has links)
As áreas protegidas, tanto públicas quanto privadas, e suas áreas de entorno têm desempenhado um papel relevante na sobrevivência de diversas espécies de mamíferos de médio e grande porte. Por essa razão, este estudo teve como primeiro objetivo estimar a riqueza de espécies de mamíferos de médio e grande porte no interior de três áreas de estudo com diferentes níveis de proteção, assim como nas suas respectivas áreas de entorno. Em segundo, e como principal objetivo deste trabalho, foi estimar as probabilidades de ocupação () e detecção (p) de uma espécie ameaçada, o tamanduá-bandeira (Myrmecophaga tridactyla), assim como avaliar se a ocorrência e o período de atividade dessa espécie são afetados pela presença humana. Todos os dados foram coletados por armadilhas fotográficas em três áreas de estudo no nordeste do Estado de São Paulo. A riqueza de mamíferos de médio e grande porte na região de estudo não é diferente entre as áreas com diferentes níveis de proteção ou entre interior e entorno. Quanto às análises de ocupação (uso), todas as covariáveis que influenciaram foram associadas com atividades humanas, positivamente para estradas e para áreas protegidas, e negativamente para proporção de área urbana. A relação positiva com estradas não pavimentadas é inesperada e pode sugerir que a espécie prefere mover-se ao longo da paisagem usando estradas para minimizar o tempo de viagem ou maximizar o forrageamento em paisagens alteradas. A presença humana não afetou positivamente ou negativamente o uso do espaço pelo tamanduá-bandeira, já que ambos ocorreram de maneira independente um do outro ( = 1). Este achado sugere que a falta de influência resulta em parte das características da paisagem de estudo (pressão de caça aparentemente baixa e uma razoável proporção de habitats nativos ainda presentes e protegidos), do desenho amostral empregado (concentrado em áreas protegidas e nas suas zonas de amortecimento) e, provavelmente, da baixa sobreposição nos períodos de atividades encontrada entre ambas espécies. Portanto, esses resultados indicam que tanto a sobrevivência da comunidade de mamíferos como, especificamente, do tamanduá-bandeira na região de estudo é fortemente dependente tanto das unidades de conservação (UC) como das áreas de vegetação nativas existentes em propriedades privadas protegidas pelo Código Florestal Brasileiro, além dos habitats perturbados no entorno dos grandes remanescentes. Todos os resultados encontrados são importantes para embasar a criação de novas áreas protegidas, assim como para o estabelecimento e manejo de zonas de amortecimento, pois indicam que estas têm papel chave na redução dos efeitos das atividades humanas sobre as UCs e na manutenção de populações viáveis das espécies presentes na região. / Protected areas, both public and private areas, and their surroundings have played an important role in the survival of several species of medium and large mammals. For this reason, this study aimed firstly to estimate the species richness of medium and large mammals within three study areas with different levels of protection, as well as their respective surrounding areas. Second, as the main goal of this study, it was to estimate occupancy () and detection (p) probability of an endangered species, the giant anteater (Myrmecophaga tridactyla), also assess if the occurrence and activity period of this species are affected by human presence. All data were collected by camera traps in three study areas in the northeast of São Paulo state. The species richness is not different between areas with different levels of protection or between interior and surroundings. Regarding occupancy analysis (use), all covariates that influenced giant anteater use were associated with human activities, positively to unpaved roads and protected areas, and negatively to proportion of urban area. The positive relationship with unpaved roads is unexpected and may suggest that giant anteater prefers to move along landscape using roads, perhaps to minimize travelling time or maximize foraging in altered landscapes. The human presence did not affect positively or negatively the use of space by giant anteater, since both species occurred independently of each other ( = 1). This finding suggests that lack of influence results in part from the landscape features of study area (apparently low hunting pressure and a reasonable proportion of native habitats still present and protected), the sampling design applied (focused on protected areas and their buffer zones) and probably due to low overlap between activity periods of both two species. Overall, results indicate that both mammals community and, specifically, giant anteater survivorship in the study region are strongly dependent upon the existence of nature reserves and areas of native vegetation existing in private properties which area protected by the Brazilian Forest Code, as well as the disturbed surrounding. All findings are important to support the creation of new protected areas, as well as the establishment and management of buffer zones, because they indicate that these zones have a key role in reducing the effects of human activities on protected areas and in the maintenance of viable species populations in the region.
53

Composição e dinâmica da comunidade de aves em fragmento de mata atlântica no extremo norte do Rio Grande do Sul

Santos, Marcelo Fischer Barcellos dos 27 February 2009 (has links)
Made available in DSpace on 2015-03-05T16:20:40Z (GMT). No. of bitstreams: 0 Previous issue date: 27 / Universidade do Vale do Rio dos Sinos,Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho teve como objetivos caracterizar a estrutura, composição e dinâmica da comunidade de aves em um fragmento de Mata Atlântica localizado no extremo norte do estado do Rio Grande do Sul, bem como realizar análises comparativas entre interior e borda de floresta em relação a (1) composição de espécies, (2) riqueza, (3) abundância de grupos funcionais de aves e (4) abundância de espécies endêmicas de Mata Atlântica. Foram definidos 22 grupos funcionais de aves para descrição geral do fragmento de floresta estudado e comparação entre interior e borda de floresta, entretanto apenas 11 puderam ser comparados a nível estatístico, os demais grupos não obtiveram suficiência amostral para serem incluídos nas análises. Os grupos funcionais utilizados na comparação de abundância entre borda e interior de floresta foram: granívoros/insetívoros generalistas, granívoros/frugívoros de solo, insetívoros de sub-bosque, insetívoros de sub-bosque e estrato médio, insetívoros escaladores de troncos e galhos, ins / The present goal was to characterize structure, composition and dynamics of bird community at an Atlantic Forest remnant at the extreme north of Rio Grande do Sul State as well to compare interior and forest edge related to (1) species composition, (2) richness, (3) abundance of functional groups and (4) Atlantic Forest abundance of endemics bird species. General description of the fragment and comparisons between forest interior and edge were based on 22 defined functional groups, however only 11 could be compared to statistical level, the other groups did not obtain sufficient sample data to be included in the analysis. Functional groups used in the comparison between the abundance of forest edge and interior were: generalist seedeater/insectivores, ground seedeater/frugivores, understory insectivores, mid and understory insectivores, tunk and twig insectivores, bamboo or forest tangle insectivores, canopy insectivores, mid and understory insectivore/frugivores, canopy insectivore/frugivores, nectarivore/in
54

Dynamics of woody vegetation patches in semiarid ecosystems in the southeast of Iberian Peninsula

Amat Martínez, Beatriz 08 May 2015 (has links)
No description available.
55

New Zealand Calanoid Copepod Invasions: Has Artificial Lake Construction Facilitated Invasions, and are our Coastal Waters Uninvaded?

Banks, Christopher Mark January 2007 (has links)
Non-indigenous species have become a global issue of increasing importance in recent years, with many causing significant environmental and economic damage. Identifying locations vulnerable to invasion allows for focus of management efforts towards prevention of invasions at those locations. In order to determine whether constructed water bodies, such as reservoirs, ornamental lakes or retired mines, are more easily invaded environments than natural water bodies, owing to decreased biotic resistance, the distributions of native and non-indigenous freshwater calanoid copepod species in the North Island were examined. Calanoid copepods in ports and other coastal environments were also examined, in order to determine whether ports are more frequently invaded owing to increased propagule supplies from visiting ships and other sources. The distributions of the native freshwater calanoid copepod species Boeckella hamata, B. propinqua, B. delicata and B. tanea are confined in the North Island of New Zealand to specific technostratigraphic terranes when natural waters only are examined, and as such each species can be considered to have a native range. The recently colonised calanoid copepod species Boeckella minuta (6 locations), Skistodiaptomus pallidus (3 locations) and Sinodiaptomus valkanovi (2 locations) are to date confined to constructed water bodies. Boeckella symmetrica (2 locations) may be confined to constructed water bodies, but the status of one location is unclear. Boeckella triarticulata, a species common in the South Island, is known only from a single farm dam in the North Island. The native species Boeckella hamata, B. propinqua and B. delicata were found to occur in constructed waters, but only B. propinqua was found in constructed water bodies outside their natural ranges (9 locations). Calamoecia lucasi is found in lakes throughout most of the North Island, and is not confined to any one terrane. My results indicate that constructed water bodies are more easily invaded by non-indigenous species than natural water bodies, represents a potential pathway for future invaders to establish, and provides locations for species to spread. In order to determine whether recently established freshwater calanoid copepod species have the potential to spread from their present habitats into other water bodies, the prosomal lengths of non-indigenous calanoid copepod species were measured and compared with those for native species. The results suggest that dietary overlap should prevent the non-indigenous species present to date from spreading into any water bodies with established Boeckella populations, although Sinodiaptomus valkanovi and Boeckella triarticulata could potentially spread to lakes containing only Calamoecia lucasi. Data on the co-occurrences of native freshwater calanoid copepod species support the theory of dietary exclusion, as Boeckella species have not been found to coexist. In order to test whether New Zealand marine environments have been invaded by non-indigenous calanoid copepods, and whether ports have been more regularly invaded than non-port areas, calanoid copepods were sampled from various coastal locations around the North Island. With the possible exception of Sulcanus conflictus, no non-indigenous species were found, indicating that non-indigenous marine calanoid copepod species are not establishing in New Zealand despite a history of invasion elsewhere.
56

Resource Lean and Portable Automatic Text Summarization

Hassel, Martin January 2007 (has links)
Today, with digitally stored information available in abundance, even for many minor languages, this information must by some means be filtered and extracted in order to avoid drowning in it. Automatic summarization is one such technique, where a computer summarizes a longer text to a shorter non-rendundant form. Apart from the major languages of the world there are a lot of languages for which large bodies of data aimed at language technology research to a high degree are lacking. There might also not be resources available to develop such bodies of data, since it is usually time consuming and requires substantial manual labor, hence being expensive. Nevertheless, there will still be a need for automatic text summarization for these languages in order to subdue this constantly increasing amount of electronically produced text. This thesis thus sets the focus on automatic summarization of text and the evaluation of summaries using as few human resources as possible. The resources that are used should to as high extent as possible be already existing, not specifically aimed at summarization or evaluation of summaries and, preferably, created as part of natural literary processes. Moreover, the summarization systems should be able to be easily assembled using only a small set of basic language processing tools, again, not specifically aimed at summarization/evaluation. The summarization system should thus be near language independent as to be quickly ported between different natural languages. The research put forth in this thesis mainly concerns three computerized systems, one for near language independent summarization – The HolSum summarizer; one for the collection of large-scale corpora – The KTH News Corpus; and one for summarization evaluation – The KTH eXtract Corpus. These three systems represent three different aspects of transferring the proposed summarization method to a new language. One aspect is the actual summarization method and how it relates to the highly irregular nature of human language and to the difference in traits among language groups. This aspect is discussed in detail in Chapter 3. This chapter also presents the notion of “holistic summarization”, an approach to self-evaluative summarization that weighs the fitness of the summary as a whole, by semantically comparing it to the text being summarized, before presenting it to the user. This approach is embodied as the text summarizer HolSum, which is presented in this chapter and evaluated in Paper 5. A second aspect is the collection of large-scale corpora for languages where few or none such exist. This type of corpora is on the one hand needed for building the language model used by HolSum when comparing summaries on semantic grounds, on the other hand a large enough set of (written) language use is needed to guarantee the randomly selected subcorpus used for evaluation to be representative. This topic briefly touched upon in Chapter 4, and detailed in Paper 1. The third aspect is, of course, the evaluation of the proposed summarization method on a new language. This aspect is investigated in Chapter 4. Evaluations of HolSum have been run on English as well as on Swedish, using both well established data and evaluation schemes (English) as well as with corpora gathered “in the wild” (Swedish). During the development of the latter corpora, which is discussed in Paper 4, evaluations of a traditional sentence ranking text summarizer, SweSum, have also been run. These can be found in Paper 2 and 3. This thesis thus contributes a novel approach to highly portable automatic text summarization, coupled with methods for building the needed corpora, both for training and evaluation on the new language. / Idag, med ett överflöd av digitalt lagrad information även för många mindre språk, är det nära nog omöjligt att manuellt sålla och välja ut vilken information man ska ta till sig. Denna information måste istället filteras och extraheras för att man inte ska drunkna i den. En teknik för detta är automatisk textsammanfattning, där en dator sammanfattar en längre text till en kortare icke-redundant form. Vid sidan av de stora världsspråken finns det många små språk för vilka det saknas stora datamängder ämnade för språkteknologisk forskning. För dessa saknas det också ofta resurser för att bygga upp sådana datamängder då detta är tidskrävande och ofta dessutom kräver en ansenlig mängd manuellt arbete. Likväl behövs automatisk textsammanfattning för dessa språk för att tämja denna konstant ökande mängd elektronsikt producerad text. Denna avhandling sätter således fokus på automatisk sammanfattning av text med så liten mänsklig insats som möjligt. De använda resurserna bör i så hög grad som möjligt redan existera, inte behöva vara skapade för automatisk textsammanfattning och helst även ha kommit till som en naturlig del av en litterär process. Vidare, sammanfattningssystemet bör utan större ansträngning kunna sättas samman med hjälp av ett mindre antal mycket grundläggande språkteknologiska verktyg, vilka inte heller de är specifikt ämnade för textsammanfattning. Textsammanfattaren bör således vara nära nog språkoberoende för att det med enkelhet kunna att flyttas mellan ett språk och ett annat. Den forskning som läggs fram i denna avhandling berör i huvudsak tre datorsystem, ett för nära nog språkoberoende sammanfattning – HolSum; ett för insamlande av stora textmängder – KTH News Corpus; och ett för utvärdering av sammanfattning – KTH eXtract Corpus. Dessa tre system representerar tre olika aspekter av att föra över den framlagda sammanfattningsmetoden till ett nytt språk. En aspekt är den faktiska sammanfattningsmetoden och hur den påverkas av mänskliga språks högst oregelbundna natur och de skillnader som uppvisas mellan olika språkgrupper. Denna aspekt diskuteras i detalj i kapitel tre. I detta kapitel presenteras också begreppet “holistisk sammanfattning”, en ansats tillsjälvutvärderande sammanfattning vilken gör en innehållslig bedömning av sammanfattningen som en helhet innan den presenteras för användaren. Denna ansats förkroppsligas i textsammanfattaren HolSum, som presenteras i detta kapitel samt utvärderas i artikel fem. En andra aspekt är insamlandet av stora textmängder för språk där sådana saknas. Denna typ av datamängder behövs dels för att bygga den språkmodell som HolSum använder sig av när den gör innehållsliga jämförelser sammanfattningar emellan, dels behövs dessa för att ha en tillräckligt stor mängd text att kunna slumpmässigt extrahera en representativ delmängd lämpad för utvärdering ur. Denna aspekt berörs kortfattat i kapitel fyra och i mer önskvärd detalj i artikel ett. Den tredje aspekten är, naturligtvis, utvärdering av den framlagda sammanfattningsmetoden på ett nytt språk. Denna aspekt ges en översikt i kapitel 4. Utvärderingar av HolSum har utförts både med väl etablerade datamängder och utvärderingsmetoder (för engelska) och med data- och utvärderingsmängder insamlade specifikt för detta ändamål (för svenska). Under sammanställningen av denna senare svenska datamängd, vilken beskrivs i artikel fyra, så utfördes även utvärderingar av en traditionell meningsextraherande textsammanfattare, SweSum. Dessa återfinns beskrivna i artikel två och tre. Denna avhandling bidrar således med ett nydanande angreppssätt för nära nog språkoberoende textsammanfattning, uppbackad av metoder för sammansättning av erforderliga datamängder för såväl modellering av som utvärdering på ett nytt språk. / QC 20100712
57

Automated Ice-Water Classification using Dual Polarization SAR Imagery

Leigh, Steve January 2013 (has links)
Mapping ice and open water in ocean bodies is important for numerous purposes including environmental analysis and ship navigation. The Canadian Ice Service (CIS) currently has several expert ice analysts manually generate ice maps on a daily basis. The CIS would like to augment their current process with an automated ice-water discrimination algorithm capable of operating on dual-pol synthetic aperture radar (SAR) images produced by RADARSAT-2. Automated methods can provide mappings in larger volumes, with more consistency, and in finer resolutions that are otherwise impractical to generate. We have developed such an automated ice-water discrimination system called MAGIC. The algorithm first classifies the HV scene using the glocal method, a hierarchical region-based classification method. The glocal method incorporates spatial context information into the classification model using a modified watershed segmentation and a previously developed MRF classification algorithm called IRGS. Second, a pixel-based support vector machine (SVM) using a nonlinear RBF kernel classification is performed exploiting SAR grey-level co-occurrence matrix (GLCM) texture and backscatter features. Finally, the IRGS and SVM classification results are combined using the IRGS approach but with a modified energy function to accommodate the SVM pixel-based information. The combined classifier was tested on 61 ground truthed dual-pol RADARSAT-2 scenes of the Beaufort Sea containing a variety of ice types and water patterns across melt, summer, and freeze-up periods. The average leave-one-out classification accuracy with respect to these ground truths is 95.8% and MAGIC attains an accuracy of 90% or above on 88% of the scenes. The MAGIC system is now under consideration by CIS for operational use.
58

Trajectories of Pure and Co-Occurring Internalizing and Externalizing Problems from Age 2 to Age 12: Findings from the NICHD Study of Early Child Care

Fanti, Kostas Andrea 03 May 2007 (has links)
According to previous research, internalizing and externalizing problems tend to be comorbid or co-occur at different ages in development (Angold, Costello, & Erkanli, 1999). The question that this dissertation addresses is how and why internalizing and externalizing problems, two disorders that represent separate forms of psychopathology, co-occur in children. This is an important question for the developmental psychopathology perspective because an appreciation of the concept of co-occurrence is essential for explaining the development and taxonomy of internalizing and externalizing psychopathology, and for understanding the etiology and course of these symptoms (Achenbach, 1990). Attempts to explain co-occurrence have proposed that co-occurring psychopathology might represent distinct, meaningful syndromes (Angold & Costello, 1992; O’Connor et al., 1998), and in support of this idea, evidence of the existence of pure and co-occurring internalizing and externalizing problems has been found (Keiley et al., 2003). However, no previous study has identified heterogeneous developmental patterns of pure or combined internalizing and externalizing problems within a dynamic framework by taking trajectories of change into account. This dissertation uses data from the NICHD study of Early Child Care to explore the co-occurrence between internalizing and externalizing problems from age 2 to 12 with the use of Latent Class Growth Analysis. The sample included 1232 children (52% male). Different groups of children exhibiting low/normative, pure internalizing, pure externalizing, and co-occurring internalizing and externalizing problems across the 10 year period were identified. The higher risk groups deviated from the low/normative group in terms of antecedents, SES risk, medical risk, difficult temperament, and home environment. Moreover, children who exhibited pure moderate externalizing problems, and children who exhibited chronic externalizing problems, with and without co-occurring internalizing problems, engaged in more risky behaviors and were more likely to have friends who also engaged in risky behaviors. Furthermore, the pure chronic externalizing group and the groups scoring high on internalizing problems, with and without co-occurring externalizing problems, were more asocial with peers. Finally, children exhibiting chronic co-occurring externalizing and internalizing problems were more excluded by peers in comparison to the rest of the sample’s population.
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Spécification d'une architecture émergente fondée sur le raisonnement par analogie. Application aux références bibliographiques

Parmentier, François 09 June 1998 (has links) (PDF)
BAsCET est un système multi-agents à « blackboard », fondé sur l'émergence de concepts dans un modèle dynamique et inspiré de COPYCAT. Pour éviter un raisonnement déterministe unique limitant sa<br />créativité il adapte son comportement en fonction de la solution courante. Nous l'avons appliqué à la reconnaissance automatique de la structure logique (des champs) de références bibliographiques dans les articles scientifiques (en format uniquement physique, c'est-à-dire en PostScript). Le modèle, appelé Réseau de Concepts, s'apparentant à la fois aux réseaux sémantiques et aux réseaux de neurones, est construit automatiquement à partir d'une base de références BIBTeX. Le système utilise les co-occurrences entre les termes des références pour rapprocher dans le modèle ceux qui sont conceptuellement voisins. Le principe de l'analogie est utilisé sur les références de la base : quand le système rencontre une référence inconnue, il fait l'analogie avec la partie physique de la base et essaye de proposer une solution correspondante. Les résultats obtenus, bien que modérés (65,5% de reconnaissance), laissent augurer des résultats encore meilleurs, après optimisation du système.
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Ταξινόμηση δεδομένων ραντάρ συνθετικού ανοίγματος (SAR) με χρήση νευρωνικών δικτύων

Μουστάκα, Μαρία 30 April 2014 (has links)
Η χρήση των δεδομένων Ραντάρ Συνθετικού Ανοίγματος (SAR) σε εφαρμογές απομακρυσμένης παρακολούθησης της Γης έχει ήδη αρχίσει να πρωταγωνιστεί τις τελευταίες δεκαετίες. Τα συστήματα SAR με δυνατότητες μεταξύ άλλων συνεχούς λειτουργίας παντός καιρού, ημέρα και νύχτα, προσφέροντας μεγάλη κάλυψη εδάφους και με δυνατότητα λήψης απεικονίσεων πολλαπλών πολώσεων, έχουν αποτελέσει πηγή πολύτιμων πληροφοριών τηλεπισκόπησης. Έτσι, η χρήση των SAR δεδομένων για την ταξινόμηση κάλυψης γης προσελκύει όλο και περισσότερο την προσοχή των ερευνητών και φαίνεται να είναι πολλά υποσχόμενη. Η παρούσα ειδική επιστημονική εργασία έχει στόχο τη μελέτη και ερμηνεία των δεδομένων SAR μέσω επιβλεπόμενης ταξινόμησης, με τη χρήση νευρωνικών δικτύων (Neural Networks). Αφού πρώτα γίνεται εκτενής αναφορά στη τεχνολογία και τα συστήματα SAR, παρουσιάζεται αναλυτικά η πειραματική διαδικασία ταξινόμησης τριών βασικών δομών κάλυψης γης. Τα δεδομένα προέρχονται από το Προηγμένο Ραντάρ Συνθετικού Ανοίγματος (ASAR) του δορυφόρου ENVISAT από τον Ευρωπαϊκό Οργανισμό Διαστήματος και αφορούν στην ευρύτερη περιοχή του Άμστερνταμ. Πριν την διεξαγωγή της ταξινόμησης, τα δεδομένα δέχθηκαν τις απαραίτητες διαδικασίες προ-επεξεργασίας (ραδιομετρική βαθμονόμηση, γεωαναφορά, φιλτράρισμα θορύβου, συμπροσαρμογή). Όσον αφορά τη διαδικασία της ταξινόμησης, εξετάζεται η συμπεριφορά του ταξινομητή του νευρωνικού δικτύου για μεταβολές ποικίλων παραμέτρων, όπως η επιλογή δεδομένων διαφόρων πολώσεων, το πλήθος των νευρώνων κ.α. και ήδη από τα πρώτα πειράματα λαμβάνονται ικανοποιητικά αποτελέσματα. Στη συνέχεια εφαρμόζονται τεχνικές σύνθεσης πληροφορίας (average rule, majority rule) βελτιώνοντας τις επιδόσεις ταξινόμησης. Τέλος, ένα σημαντικό βήμα που εφαρμόζεται στη διαδικασία ταξινόμησης αποτελεί η εξαγωγή χαρακτηριστικών υφής από τις μήτρες συνεμφάνισης φωτεινοτήτων (Gray Level Co-occurrence Matrix-GLCM) και μήκους διαδρομής φωτεινότητας (Gray Level Run Length Matrix-GLRLM). Η χρήση των χαρακτηριστικών αυτών βελτιστοποιεί το σύστημα ταξινόμησης, δίνοντας εξαιρετικά αποτελέσματα. / The use of Synthetic Aperture Radar (SAR) data in remote sensing applications has become a cutting edge technology during the past few decades. The SAR systems have several capabilities, like day & night and all weather operation and they offer large ground coverage with the ability of multi-polarized imagery; therefore, they have proved to be a valuable source of remote sensing data. As a result, the use of SAR data for land cover classification increasingly attracts the attention of researchers and seems to be highly promising. Goal of this master thesis is the study and interpretation of SAR data through supervised classification, with the use of Neural Networks method. First, there is an extensive presentation of SAR systems and technology and then follows the detailed presentation of the experimental classification process for three basic land cover structures. The available data are from the Advanced SAR (ASAR) radar of the ESA ENVISAT satellite and correspond to the Amsterdam city and suburbs. Prior to the classification process, the data have been appropriately pre-processed (radiometric calibration, geocoding, speckle filtering, co-registration). Regarding the classification process, the response of the neural network classifier with the variation of several parameters (e.g. data polarization and number of neurons) is studied and from the initial test already the results were quite satisfactory. Further on, ensemble classifying methods (average rule, majority rule) are applied to improve the classification performance. Finally, as an essential step applied in the classification process is the textural feature extraction from Gray Level Co-occurrence Matrix (GLCM) and Gray Level Run Length Matrix (GLRLM). The use of these texture features optimizes the classification system, resulting to an exceptional performance.

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