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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.
271

Microbial diversity and metal pollution from a platinum mine tailings dam in the North-West Province (RSA) / by Molemi Evelyn Rauwane.

Rauwane, Molemi Evelyn January 2008 (has links)
The aim of this study was to determine the effects of the heavy metal pollution on microbial diversity along the gradient from a platinum mine tailings dam using culture-dependent (plating methods) and molecular methods. Tailings and soil samples were collected from seven sites (6 samples per site) at increasing distances from the tailings dam. Samples were collected over a two year period and included two rainy and two dry periods. Concentrations of various heavy metals were determined using an inductively coupled plasma mass spectrometer (ICP-MS). The results demonstrated that seasonal variations in metal concentrations occurred and also that concentrations were significantly different'(P < 0.05) between the experimental sites for each metal. The relative relationship between metals was in the following order: Al > Ni > Cu > Cr. Since soil metal concentration benchmarks for South Africa are lacking, the concentrations were compared to the Canadian microbial benchmarks (MB) and Netherlands maximum permissible concentrations (MPC). Concentrations of most of the heavy metals exceeded the MB and MPC. Levels and diversity of culturable fungi and bacteria at each site were determined using plate count methods. Results indicated that levels of bacteria and fungi were not suppressed by high concentrations of heavy metals. Significantly higher levels (P < 0.05) of fungi were found at the sites on the tailings dam (higher concentrations of heavy metals), compared to sites more than 300 m away. A commonly used soil health index (Shannon-Weaver diversity index) was used to compare microbial community diversity at each site and to evaluate whether or not the heavy metal contamination impacted negatively on these soil bacterial and fungal communities. Shannon-Weaver diversity indices were higher at sites on and close to the tailings dam than sites more than 300 m away. However, ratio of fungal to bacterial levels as determined by plate counts was inconsistent. Representatives of bacterial species that were grouped using colony morphology and whole cell protein profiles were identified by 16S rDNA sequences as Bacillus barbaricus (B. barbaricus) and -Paenibacillus lautus {P. Lautus). Restriction enzyme digest, SDS-PAGE and random amplified polymorphic DNA (RAPD) analyses provided supporting evidence that representatives were correctly grouped. Cluster analysis results demonstrated that the RAPD profiles of the metal tolerant P. lautus representatives were sufficiently dissimilar to discriminate between individuals from the spatially separated sites. The spatially separated sites also represented sites with high and low heavy metal concentrations. Observed genetic variability was thus also associated with varying levels of heavy metals. In conclusion, this study demonstrated the potential of using RAPD analysis as biomarkers for genotoxic effects of heavy metals on bacterial genomes. / Masters / Thesis (M.Sc. (Microbiology))--North-West University, Potchefstroom Campus, 2009.
272

The use of diatoms to indicate water quality in wetlands : A South African perspective / by Malebo D. Matlala

Matlala, Malebo Desnet January 2010 (has links)
In a semi-arid country like South Africa, the availability and quality of water has always played an important part in determining not only where people can live, but also their quality of life. The supply of water is also becoming a restriction to the socio-economic development of the country, in terms of both the quality and quantity of what is available. Thus different monitoring techniques should be put in place to help inform the process of conserving this precious commodity and to improve the quality of what is already available. Water quality monitoring has traditionally been by the means of physico-chemical analysis; this has more recently been augmented with the use of biomonitoring techniques. However, since the biota commonly used to indicate aquatic conditions are not always present in wetlands; this study tested the use of diatoms as bio-indicators in wetlands. Diatom samples were collected from thirteen wetlands in the Western Cape Province, and cells from these communities were enumerated and diatom ?based indices were calculated using version 3.1 of OMNIDIA. These indices were useful for indicating water quality conditions when compared to the measured physico-chemical parameters. In addition, most diatom species found were common to those found in riverine environments, making the transfer of ecological optima possible. The objective of the study was to provide a preliminary diatom-based index for wetlands, however, given the relatively small study area and the strong bias towards coastal wetlands it was deemed inadvisable to construct such an index, instead several indices are recommended for interim use until further research that more comprehensively covers wetlands in South Africa has been conducted. It is thus the recommendation of this study that more data is collected for comparison to other wetlands and that in the interim, indices such as SPI be applied for routine biomonitoring of these environments. / Thesis (M.Sc. (Botany))--North-West University, Potchefstroom Campus, 2010.
273

Monthly house price indices and their applications in New Zealand : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy, Department of Economics and Finance, College of Business, Massey University

Shi, Song January 2009 (has links)
Developing timely and reliable house price indices is of interest worldwide, because these measures influence consumer behaviour, inflation targeting, and spot and futures markets. Several techniques for constructing a constant quality price index are available in the literature, but these methods are difficult to apply in localities where market transaction data is limited. Since house price movements are a local phenomena, improving the timeliness of a quality controlled price index at local housing market levels in small countries like New Zealand is a challenge. This thesis comprises three essays that focused on improving the timeliness of reported house price indices at the local market levels. The timeliness issue examined in this thesis has not previously been rigorously investigated and this makes the results of this thesis both important and unique for the benefit of both academic research and practical application. Essay One reviews the sale price appraisal ratio (SPAR) method, which has been applied since the 1960s for producing local house price indices at a semi-annual and quarterly basis in New Zealand. Utilizing a variety of statistical tests and comparing this index with the repeat sales and median price index result in the study highlighting the potential of, as well as the problems associated with, a price index produced by the SPAR method at a monthly level. In the following two essays, monthly price indices are tested using empirical real estate research methods in order to examine their usefulness in exploring the research questions as well as revealing the statistical differences between them. Essay Two studies the relationship between sale price and trading volume, and the ripple effect of local house price comovements. The results show that the trading volume generally leads the sale price in the long-run and the ripple effect is most likely constrained within regions. In Essay Two, the monthly SPAR index produces similar statistical results to those estimated by the repeat sales index for large cities. Essay Three is a study on the market efficiency of housing markets. It is found the local housing market is neither weak-form nor semi-strong form efficient. Local house price movements are strongly correlated and are mean reverting towards their long-run equilibrium. It is further concluded that monthly price indices for small cities are problematic due to the problem of small sample size. Overall, the findings in this thesis show monthly house price indices can be generated by using the SPAR method at local market levels. However, this potential is limited to large cities. Further research can focus on improving the quality of monthly price indices for large cities.
274

Information, rendement, stratégies neutres et limites à l'arbitrage en bourse suisse (1993-2000) /

Ruffa, Michel. January 2004 (has links)
Thèse (Ph. D.)--Université Laval, 2004. / Bibliogr.: f. [95]-101. Publié aussi en version électronique.
275

Απόβλητα ελαιοτριβείου και βιολογικές επιπτώσεις τους σε ιστούς του κοινού μυδιού Mytilus galloprovincialis

Δανελλάκης, Δημήτριος 10 June 2013 (has links)
Στην παρούσα μελέτη διερευνώνται οι πιθανές επιπτώσεις των αποβλήτων που προέρχονται από ελαιοτριβεία τριών φάσεων σε ιστούς του μυδιού Mytilus galloprovincialis. Άτομα που εκτέθηκαν για 5 ημέρες σε διαφορετικές αραιώσεις/συγκεντρώσεις του αποβλήτου παρουσίασαν μεγάλη θνησιμότητα σε αραιώσεις 1/1000 και 1/500, ενώ έκθεση των μυδιών σε μεγαλύτερες αραιώσεις του αποβλήτου (1/1000 και 1/10000), έδειξε μικρότερη θνησιμότητα. Οι υπο-θανατογόνες συγκεντρώσεις του αποβλήτου χρησιμοποιήθηκαν για την εκτίμηση α) της σταθερότητας των λυσοσωμικών μεμβρανών σε αιμοκύτταρα της αιμολέμφου (lysosomal membrane stability/LMS), β) της συχνότητας εμφάνισης μικροπυρήνων (micronuclei frequency/MN) και κυτταρικών ανωμαλιών σε αιμοκύτταρα, γ) της δραστικότητας της ακετυλ-χολινεστεράσης (AChE) στην αιμόλεμφο και τα βράγχια των εκτιθέμενων ατόμων, καθώς και ε) την εκτίμηση των επιπέδων των μεταλλοθειονινών (ΜΤ) στα βράγχια. Σύμφωνα με τα αποτελέσματα, άτομα που εκτέθηκαν σε αραιώσεις 1/1000 και 1/1000 του αποβλήτου, εμφάνισαν σημαντική μείωση του χρόνου αποσταθεροποίησης των λυσοσωμικών μεμβρανών των αιμοκυττάρων τους, με ταυτόχρονη αύξηση της συχνότητας εμφάνισης μικροπυρήνων και κυτταρικών ανωμαλιών. Επιπλέον, σημαντική μείωση της δραστικότητας της AChE παρατηρήθηκε σε όλους τους ιστούς (αιμόλεμφος και βράγχια), σε σχέση με τα αντίστοιχα επίπεδα δραστικότητας που μετρήθηκαν στους ιστούς ατόμων που δεν εκτέθηκαν στο απόβλητο, ενώ σημαντική αύξηση των επιπέδων ΜΤ παρατηρήθηκαν στα βράγχια των εκτιθέμενων ατόμων. Σύμφωνα με τα αποτελέσματα, το υψηλό οργανικό φορτίο, η μεγάλη συγκέντρωση φαινολών, καθώς και η ύπαρξη μεταλλικών στοιχείων μπορεί να ευθύνονται για την πρόκληση των επιβλαβών επιπτώσεων του αποβλήτου σε υδρόβιους οργανισμούς, όπως τα Δίθυρα μαλάκια, προκαλώντας σημαντικές βλάβες τόσο σε κυτταρικό όσο και σε μοριακό επίπεδο. / The present study investigates the biological effects of olive oil mill wastewaters (OMW) on tissues of mussels Mytilus galloprovincialis. Mussels exposed to different quantities of OMW (dilution factors 1/100 and 1/500) for 5 days showed increased levels of mortality, while mussels’ mortality observed after exposure to lower quantities of the OMW (dilution factors 1/1000 and 1/1000) was negligible. According to the latter, prepathological alterations occurred in tissues of mussels exposed to sub-lethal concentrations of OMW were further investigated with the use of stress-indices, such as lysosomal membrane stability (via the neutral red retention time assay/NRRT), acetylcholinesterase (AChE) activity, metallothionein (MT) content and micronuclei frequency (MN). According to the results of the present study, decreased NRR time values and significantly elevated levels of MN and nuclear abnormalities were observed in haemocytes of exposed mussels in each case. Moreover, mussels exposed to either 1/1000 or 1/10000 diluted OMW showed significantly decreased levels of AChE activity in haemolymph and gills, as well as increased MT levels in gills, compared with levels measured in the respective tissues of control mussels. The results of the present study indicates that biological effects of OMW could be due to the high organic loading toxicity of OMW, its high levels of phenolic compounds, as well as the presence of metallic anions, thus giving rise to the hypothesis that short-time exposure of marine organism to OMW could resulted in the induction of severe cytotoxic and genotoxic damage.
276

Implementação e avaliação de modelos de poços em duas e três dimensões para aplicação em simuladores de reservatórios de petróleo

Ribeiro, Gustavo Gondran 25 October 2012 (has links)
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2010 / Made available in DSpace on 2012-10-25T12:13:54Z (GMT). No. of bitstreams: 1 284632.pdf: 2497288 bytes, checksum: 17a080701715be6ce4558367120f3718 (MD5) / Na simulação de reservatórios de petróleo, o maior problema encontrado é a diferença de escalas entre o reservatório e os poços de exploração. O reservatório é da ordem de quilômetros e o diâmetro dos poços é da ordem de centímetros. Portanto, para realizar a simulação de um reservatório nas vizinhanças dos poços seria necessário uma malha muito refinada para poder captar os gradientes próximos aos poços. A utilização de uma malha muito refinada, por sua vez, acarretaria um esforço computacional muito grande e custoso a medida que seriam inseridas no problema as complexidades físicas. Devido a isso, utilizar malhas que tenham um tamanho compatível com a escala do reservatório e inserir os poços como termos fonte nos volumes de controle onde os mesmos estão localizados, apresenta-se como uma solução viável na simulação de reservatórios. Neste caso, é necessário a introdução de um modelo que consiga representar a física nas vizinhanças dos poços. Os modelos mais utilizados na indústria de petróleo empregam uma solução analítica local, na qual a conexão entre a vazão mássica e o gradiente de pressão nas proximidades do poço é feita através da representação de um escoamento radial cilíndrico. Esses modelos, entretanto foram desenvolvidos para aplicação em duas dimensões. Com o desenvolvimento de novas tecnologias na perfuração de poços de petróleo, sugiram os poços horizontais, onde a aplicação dos modelos de poços exige uma nova visão. No presente trabalho foi realizada uma extrapolação dos modelos de poços tradicionais em duas dimensões para três dimensões, utilizando domínios em formato de cubo, ou paralelepípedo, para aplicação em poços horizontais parcialmente penetrante, isto é, onde os poços não atravessam o domínio por inteiro. Para isto foi considerado além da solução analítica local para um fluxo radial cilíndrico, uma solução analítica com fluxo radial esférico nas extremidades dos poços horizontais, devido ao comportamento do fluxo nestas extremidades. Todos os modelos obtiveram bons resultados, mostrando sua capacidade de representar a física na vizinhança dos poços.
277

Estudo de eventos hidrológicos extremos na bacia do Rio do Peixe - SC com aplicação de índice de umidade desenvolvido a partir do tank model

Lindner, Elfride Anrain January 2007 (has links)
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia Ambiental / Made available in DSpace on 2012-10-22T23:49:13Z (GMT). No. of bitstreams: 1 245780.pdf: 8726094 bytes, checksum: c0024a3e3297ddf3c4b30fe86c40ac8c (MD5) / A Bacia Rio do Peixe, no Meio-Oeste do Estado de Santa Catarina, sofre de desastres naturais, causados pelo excesso e pela escassez de precipitação. A bacia foi estudada em quatro áreas incrementais, nas sub-bacias delimitadas pelas estações fluviométricas de Rio das Antas (Pe1, 803 km2); de Tangará (Pe2, 2.018 km2); de Joaçaba (Pe4, 3.708 km2) e de Piratuba (Pe4, 5.238 km2), esta última correspondendo à Bacia Rio do Peixe. Foram utilizados os dados hidrometeorológicos diários de 1977 a 2004. Os valores médios, em mm.d-1, de precipitação (P), de evapotranspiração potencial (ETP), evapotranspiração real (ETR) foram 4,70; 2,83; 2,32 (Pe1); 4,83; 2,85; 2,63 (Pe2); 4,93; 2,90; 2,53 (Pe3) e 4,95; 2,95 e 2,73 (Pe4), respectivamente. O Tank Model, com quatro reservatórios em série e doze parâmetros, foi calibrado e validado para cada uma das quatro bacias. Os valores médios diários de vazões observadas e calculadas, em mm.d-1, foram de: 2,38 e 2,43 (Pe1); 2,20 e 2,19 (Pe2); 2,40 e 2,35 (Pe3); 2,22 e 2,18 (Pe4), respectivamente. Foi utilizado um critério de objetivos múltiplos para calibração e validação, resultando no ajuste adequado do Tank Model. Os coeficientes de Nash-Sutcliffe e logaritmo de Nash foram respectivamente: 73% e 78% (Pe1); 80% e 83% (Pe2); 88 e 88% (Pe3); 84% e 84% (Pe4). O índice de umidade Tank (IUT), foi desenvolvido a partir do Tank Model, considerando o armazenamento diário de água em todos os reservatórios, com o uso de valores de tendência central (média e mediana) de toda a série histórica. O IUT, com intervalos de zero a dez, foi aplicado para analisar 290 decretos municipais de situação de emergência e/ou de calamidade pública provocados por desastres naturais decorrentes de excesso ou de escassez hídrica na bacia, para o período de 1977-2004. Sob o enfoque da mediana, o índice de umidade Tank propiciou melhor ajuste do que o uso da média, correspondendo a 84% para enchentes, em 161 decretos de excesso hídrico, e 90% para estiagem, em 129 decretos de escassez hídrica. O IUTmd e a vazão calculada pelo Tank Model tiveram 0,97 de correlação por regressão segmentada. O presente trabalho mostrou que o IUT, em base diária, é aplicável aos eventos hidrológicos extremos, sendo útil para o alerta de enchentes, como também para a análise da continuidade da estiagem. O IUT, portanto, pode ser uma ferramenta para a tomada de decisões no gerenciamento dos recursos hídricos de uma bacia. Rio do Peixe watershed, southern Brazil, has suffered natural disasters caused by excess and shortage of rainfall. The watershed was studied in four catchments, at the gauging stations of Rio das Antas (Pe1, 803 km2); Tangará (Pe2, 2,018 km2); Joaçaba (Pe4, 3,708 km2) and Piratuba (Pe4, 5,238 km2), the last corresponding to Rio do Peixe watershed. Daily hydro meteorological data were used for the period 1977 to 2004. The mean values [mm.d-1] of precipitation (P), potential evapotranspiration (ETP), real evapotranspiration (ETR) were 4.70; 2.83; 2.32 (Pe1); 4.83; 2.85; 2.63 (Pe2); 4.93; 2.90; 2.53 (Pe3); 4.95; 2.95; 2.73 (Pe4), respectively. The Tank Model, structured with four vertical reservoirs and twelve parameters, was calibrated to the four catchments and validated for the studied period. The mean daily observed and calculated discharges [mm.d-1] were: 2.38 and 2.43 (Pe1); 2.20 and 2.19 (Pe2); 2.40 and 2.35 (Pe3); 2.22 and 2.18 (Pe4), respectively. The successfulness of the optimization technique was shown using multiples objectives. The Nash-Sutcliffe and logarithmic Nash index were, respectively: 73% and 78% (Pe1); 80% and 83% (Pe2); 88 and 88% (Pe3); 84% and 84% (Pe4). The Tank Moisture Index (TMI) was developed from the Tank Model, considering the daily water storage in reservoirs 1 to 4, with the use of central tendency (average and median) of the entire historical series. TMI (range 0 to 10) was applied to analyze 290 declarations of "Emergency Situation" and "Public Calamity State" caused by natural hazards in 25 municipalities in Rio do Peixe watershed, for the period of 1977-2004. The appliance of the median produced higher adjustment compared with the use of the average approach, with TMI reaching 84% for floods, in 161 of water excess decrees, and with 90% for droughts, in 129 decrees of water shortage. TMI (median) and Tank Model calculated discharge have 97% of correlation by "segmented regression". The present study showed that Tank Moisture Index, on daily basis, applied to extreme hydrological events, is useful for floods' warnings, and also for droughts duration and severity analyses. TMI, therefore, can be a tool for making decision on watershed management and for natural hazards prevention.
278

Análise e previsão de eventos críticos de precipitação com base no SPI e em redes neurais artificiais para o Estado de Pernambuco.

GUEDES, Roni Valter de Souza. 14 August 2018 (has links)
Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-08-14T11:48:17Z No. of bitstreams: 1 RONI VALTER DE SOUZA GUEDES - TESE (PPGMet) 2016.pdf: 13257786 bytes, checksum: 624133c9b10421f7ba2d7cf8d0eacf79 (MD5) / Made available in DSpace on 2018-08-14T11:48:17Z (GMT). No. of bitstreams: 1 RONI VALTER DE SOUZA GUEDES - TESE (PPGMet) 2016.pdf: 13257786 bytes, checksum: 624133c9b10421f7ba2d7cf8d0eacf79 (MD5) Previous issue date: 2015-12-18 / CNPq / A identificação e classificação de áreas susceptíveis à ocorrência de eventos críticos, chuvosos ou secos, tornaram-se uma necessidade frequente no contexto da variabilidade climática, responsável por muitos desastres naturais em diversos países do mundo. O diagnóstico com base nos impactos meteorológicos, agrícolas e hidrológicos pode ser aferido através de índices climáticos. O Índice de Precipitação Padronizado (SPI) foi desenvolvido para diagnosticar e categorizar a variabilidade da precipitação com base em diferentes escalas temporais. A aplicação da metodologia do SPI para 57 postos distribuídos sobre o estado de Pernambuco, Nordeste do Brasil, com séries de 1963 a 2015, foi capaz de destacar e classificar as principais anomalias das chuvas através da sua intensidade e duração. As escalas menores do SPI (mensal e trimestral) indicaram o início e tendência de cada evento; a escala semestral identificou o comportamento do período chuvoso e as escalas anual e bienal definiram os eventos mais fortes e duradouros. Foram diagnosticados eventos positivos e negativos nas categorias de fraco, moderado, severo e extremo. Foram analisados os eventos que ocorreram de forma mais generalizada e, portanto, mais significativos. Foram destacados os eventos chuvosos críticos de 1963, 1973, 1984 e os eventos secos de 1993, 1998 e 2012. A análise de agrupamento utilizando a métrica de Ward foi aplicada aos SPIs para delimitar dois grupos bem definidos para qualquer escala temporal do SPI. A divisão do estado de Pernambuco ficou assim: Grupo 1, do Litoral ao Agreste e o Grupo 2 representando todo o Sertão. Os valores das anomalias de temperatura da superfície do mar foram correlacionados com cada escala do SPI e usados como entrada nos modelos baseados em Redes Neurais Artificiais (RNA) para predizer as variações deste índice na área de estudo. Os resultados mostraram que o modelo apresentou uma boa previsão com o padrão de comportamento da escala trimestral do SPI, e não obteve o mesmo nível de desempenho para as escalas mensais e semestrais, porém, o modelo de RNA conseguiu absorver a tendência dos valores destas escalas e encontrar uma boa associação. / The identification and classification of areas susceptible to critical events be it rainy or dry events, has become a frequent need in the current context of climate variability, esponsible for natural disasters in several countries in the world. The diagnosis based on meteorological, agricultural and hydrological impacts can be measured by climatic indices. The Standardized Precipitation Index (SPI) was developed to categorize and make the diagnostic the variability of the rainfall based on different temporal scales. The application of SPI methodology to 57 stations distributed about the state of Pernambuco, Northeastern Brazil, for the years 1963 to 2015, was able to highlight and rank the main anomalies of rainfall through its intensity and duration. Smaller scales the SPI (monthly and quarterly) indicated the start and trend of each event, the semiannual scale identified the behavior of rainy period and the annual and biennial scales it defined the strongest and most enduring events. Positive and negative events were diagnosed in the scale categories: low, moderate, severe and extreme. Were analyzed the events that occurred more widely and thus more significant. Were highlighted the critical rainfall events of 1963, 1973, 1984 and the dry events of 1993, 1998, 2012. The cluster analysis using the metric of Ward was applied to SPIs to delimit the two well-defined groups to any timescale of the SPI. The division of Pernambuco state was as follows: Group 1, from Coast to Agreste and Group 2 represents the entire Sertão. The values of the temperature anomalies of the sea surface were correlated with each SPI scale and used as input in models based on Artificial Neural Networks (ANN) to predict the variations of this index in the study area. The results showed that the model had a good forecast with the standard of behavior of the quarterly SPI scale, but did not get the same level of performance for the monthly and semi-annual scales, but the model the ANN was able to absorb the trend of the values of these scales and find a good association.
279

[en] DATABASE SELF-TUNING WITH PARTIAL INDEXES / [pt] SINTONIA FINA AUTOMÁTICA COM ÍNDICES PARCIAIS

ALAIN DOMINGUEZ FUENTES 27 April 2017 (has links)
[pt] Os índices parciais são estruturas de acesso no nível físico dos bancos de dados que permitem definir um subconjunto das tuplas de uma tabela, através de uma expressão condicional. Nesta dissertação estuda-se a identificação e subsequente criação automática de índices parciais que possam contribuir na melhoria do desempenho de um sistema de banco de dados. É proposto um algoritmo que examina, para cada consulta relevante, os conjuntos de atributos indexáveis para os quais a criação de um índice parcial poderia influenciar o otimizador de consultas na geração de planos mais eficientes. É realizada uma mineração de padrões de atributos indexáveis para se obter atributos correlacionados segundo a frequência das consultas na carga de trabalho considerada. Chega-se a uma proposta para um conjunto de índices parciais candidatos também se considerando uma heurística de benefícios. Realiza-se uma análise de sintonia fina em função da seleção de uma configuração de índices parciais e índices completos. A implementação das técnicas e algoritmos propostos nesta pesquisa é feita no framework DBX, que permite instanciar técnicas de sintonia fina local e global para bancos de dados relacionais. / [en] Partial indexes are access structures on the physical level of the databases. They are indexes that allow the definition of a subset of tuples in a table through a conditional expression. This dissertation studies the identification and subsequent automatic creation of partial indexes that can contribute in improving the performance of a database system. We propose an algorithm that examines, for each relevant query, the indexable attributes set, for which the creation of a partial index could influence the query optimizer to generate plans that are more efficient. We perform data mining on indexable attributes patterns to obtain correlated attributes according to their frequency in queries within the particular workload. We obtain a proposal for a set of candidate partial indexes considering also a benefit heuristics. We may consider a self-tuning analysis of an index configuration with both complete and partial indexes. We have implemented techniques and algorithms proposed in this research into DBX, a framework that allows local and global self-tuning regarding relational databases.
280

Influência da variabilidade climática na dinâmica da vegetação na região da Mata Atlântica Paulista / Influence of climatic variability on vegetation dynamics in the Atlantic Forest region of São Paulo

Carvalho, Suzana Maria Inácio de 04 June 2018 (has links)
Submitted by Suzana Maria Inácio De Carvalho (suzana-carvalho@live.com) on 2018-07-28T15:12:36Z No. of bitstreams: 1 Dissertacao_SMIC_2307_novo_repositorio.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5) / Approved for entry into archive by Lucimara Kurokawa Shinoda null (lucimaraks@sorocaba.unesp.br) on 2018-07-30T18:15:59Z (GMT) No. of bitstreams: 1 carvalho_smi_me_soro.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5) / Made available in DSpace on 2018-07-30T18:15:59Z (GMT). No. of bitstreams: 1 carvalho_smi_me_soro.pdf: 7752307 bytes, checksum: ff8be58adddeedea30e008b00bd7e4b1 (MD5) Previous issue date: 2018-06-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Alterações no clima causam impactos significativos sobre a estrutura e distribuição dos ecossistemas afetando a biodiversidade terrestre. O objetivo da pesquisa foi descrever os padrões da dinâmica da vegetação natural da Mata Atlântica Paulista na região da bacia hidrográfica do rio Paraíba do Sul (UGRHI 2) e identificar a relação que se estabelece entre a variabilidade climática e a vegetação. Dados de imagens de séries temporais de índices de vegetação como o EVI (Índice de Vegetação Melhorado), LSWI (Índice de umidade da vegetação) e LAI (Índice de Área Foliar) derivados de produtos de Sensoriamento Remoto (SR), foram adquiridos do sensor MODIS, pois são poderosas ferramentas indicadoras do desenvolvimento da vegetação. Dados de precipitação pluvial adquiridas por estações pluviométricas disponibilizadas pela ANA foram aplicados para cálculo dos índices climáticos como o SPI (Índice de Precipitação Padronizado) e RAI (Índice de Anomalia de chuva). Os índices conseguiram detectar a variação entre anos extremamente úmidos e anos extremamente secos. Destacaram-se os anos 2009 e 2014, sendo que o ano de 2009 representou um ano de anomalia positiva, com precipitação acima da média climatológica. Já em 2014, foi possível detectar uma condição de anomalia negativa, com condições mais severas com precipitação pluvial abaixo da média climatológica. Com a finalidade de avaliar como essa dinâmica climática influencia na dinâmica da vegetação, os índices EVI, LSWI e LAI foram analisados e mostraram que o comportamento da dinâmica da vegetação natural das regiões da Mata Atlântica Paulista acompanha a variabilidade do clima, já que foram observados padrões de maior produtividade no período da estação chuvosa, época em que a condição hídrica é mais intensa e favorece o verdejamento das folhas, o oposto foi observado quando há o déficit hídrico, que ocorre principalmente na estação seca onde nota-se o declínio dos valores dos índices, ou seja, indicando a queda foliar. Os índices capturaram o padrão esperado, vale destacar que o índice LSWI apresentou maior sensibilidade à condição hídrica, o que era esperado devido às bandas que compõe este índice, sendo possível verificar o potencial das imagens do sensor MODIS em capturar a resposta da floresta e consequentemente contribuir de forma significativa para estudos de mudanças climáticas. / Climate change causes significant impacts on the structure and distribution of ecosystems affecting terrestrial biodiversity. The objective of the research was to describe the patterns of the dynamics of the natural vegetation of the Atlantic forest in the region of the watershed of Rio Paraíba do Sul (UGRHI 2) and to identify the relationship that is established between climatic variability and vegetation. Image data from temporal series of vegetation indices as the improved Vegetation Index (EVI), Vegetation Humidity Index (LSWI) and foliar area index (LAI) derived from remote sensing products (SR), were acquired from the MODIS sensor, as they are Powerful tools indicating the development of vegetation. Rainfall precipitation data acquired by precipitation stations provided by the National Water Agency (ANA) were applied for calculating climatic indexes such as the Standardized Precipitation Index (SPI) and Rain Anomaly Index (RAI). The indexes were able to detect the variation between extremely humid years and extremely dry years. The years 2009 and 2014 were highlighted, and the year 2009 represented a year of positive anomaly, with precipitation above the average climatological. In 2014, it was possible to detect a negative anomaly condition, with harsher conditions with rainfall precipitation below the climatological average. For the purpose of evaluating how this climate dynamics influences the dynamics of vegetation, the indices EVI, LSWI and LAI were analyzed and showed that the behavior of the dynamics of the natural vegetation of the Regions of Atlantic Forest Paulista accompanies the Climate variability, since there were observed higher productivity patterns during the rainy season, when the water condition is more intense and favors the greenishing of the leaves, the opposite was observed when there is the water deficit, which occurs Mainly in the dry season where it is noted the decline of the values of the indices, that is, indicating the foliage fall. The indexes captured the expected pattern, it is worth noting that the LSWI index presented greater sensitivity to the water condition, which was expected due to the bands that make up this index, it is possible to verify the potential of the images of the MODIS sensor in capturing the Forest response and consequently contribute significantly to climate change studies.

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