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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

Calibração de dados agrometeorológicos e estimativa de área e produtividade de culturas agrícolas de verão no estado do Paraná / Calibration of agrometeorological data, area and yield estimation for summer crops in Parana state

Johann, Jerry Adriani 19 August 2018 (has links)
Orientadores: Jansle Vieira Rocha, Rubens Augusto Camargo Lamparelli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-19T17:37:26Z (GMT). No. of bitstreams: 1 Johann_JerryAdriani_D.pdf: 49162183 bytes, checksum: 407391759a8e7315491a3e601e3a1530 (MD5) Previous issue date: 2012 / Resumo: O caráter subjetivo dos levantamentos oficiais de produção não permite uma análise quantitativa dos erros envolvidos nem o conhecimento da sua distribuição espacial. Soluções visando à definição de metodologias mais eficazes, com menor custo, e que permitam um estudo em escala regional das estimativas agrícolas (área cultivada e produtividade) têm sido estudadas com o uso de geotecnologias. Neste trabalho, foram utilizadas imagens multitemporais do índice de vegetação EVI/MODIS, entre os anos-safra 2004/05 e 2007/08 no estado do Paraná, com o objetivo de mapear/estimar as áreas (máscaras) com as culturas de verão mais importantes (soja e milho) e estimar a produtividade da soja com modelos espectrais e mistos regionais. Também foram utilizados dados decendiais da radiação solar global, evapotranspiração de referência, temperatura média do ar e precipitação pluvial do ECMWF e de Superfície (SIMEPAR, INMET, SUDERSHA) para calibração entre as duas fontes, a fim de utilizá-los nos modelos mistos de estimativa de produtividade. Para geração dos modelos de produtividade espectrais e mistos foram selecionados 40 municípios. Para os modelos espectrais, as variáveis foram geradas ao longo do ciclo produtivo, a partir dos perfis temporais de EVI médios municipais. Para os modelos mistos, foram geradas variáveis dos dados calibrados do ECMWF por fase fenológica da soja. A seleção das variáveis deu-se pelo método estatístico stepwise para posteriormente, serem modeladas por regressão. Como resultados, foram geradas máscaras anuais destas culturas de verão, que comparadas por município, com os dados oficiais do IBGE, mostraram bons ajustes (R²>0,84; d >0,95; c>0,85) e ótima exatidão espacial (EG>92,8% e IK>0,86) utilizando com referência terrestre, imagens LANDSAT 5/TM e AWiFS/IRS. O procedimento de calibração dos 303 pixels do ECMWF sobre o estado foi realizado por meio de modelos de regressão linear simples de 10 anos de dados (2000 a 2009). Todas as variáveis agrometeorológicas estudadas, com exceção de precipitação pluvial, apresentaram elevada acurácia (d, MAE, RMSE) e precisão (R2, r) e pequena tendência (ou viés) (Es). A variável com melhor ajuste foi a temperatura média do ar, seguida pela evapotranspiração de referência e radiação solar global, com valores de c iguais a 0,83; 0,81 e 0,76, respectivamente. A calibração dos dados do ECMWF em relação à precipitação pluvial não foi significativa provavelmente devido à alta variabilidade espacial mensurados na superfície. As estimativas de produtividade de soja, obtidas por meio dos modelos espectrais, apresentaram menor acurácia (MAE, RMSE, MAPE) e precisão (r, R²) quando comparados aos obtidos pelos modelos mistos, corroborando com os resultados da literatura que indicam melhora no desempenho dos modelos de produtividade com a inserção de dados agrometeorológicos. Comparado aos dados oficiais, as estimativas realizadas pelos modelos espectrais e mistos não apresentaram tendência de subestimação e superestimação de produtividade. Como conclusões, verificou-se que a metodologia proposta para geração das máscaras foi eficiente e pode ser utilizada para um mapeamento em escala estadual, dentro das limitações da resolução espacial que caracteriza as imagens EVI/MODIS (250m). Foi possível e necessária a calibração dos dados estimados pelo ECMWF para as variáveis radiação solar global, evapotranspiração de referência e temperatura média do ar no Paraná. Não foi possível a calibração dos dados de precipitação pluvial devido à elevada variabilidade espacial mensurada pelas estações de superfície / Abstract: The subjective approach of official crop production surveys doesn't allow the quantification of errors and spatial distribution of crop areas. Studies have been carried out to find solutions for new, more efficient and lower cost methodologies for regional scale crop forecast (area and yield) using geotechnologies. In this study multitemporal EVI/MODIS images were used for the 2004/2005 and 2007/2008 cropping seasons in the Paraná State, Brazil, aiming at mapping/estimating area (masks) of summer crops (soybean and corn) and estimate soybean yield with spectral and regional agrometeorological/spectral (combined) models. Dekadal data of global solar radiation, reference evapotranspiration, mean air temperature and rainfall from the ECMWF model and surface (ground stations) were intercalibrated in order to use in the combined models of yield estimation. The models were applied to 40 municipalities. For the spectral models the variables were generated throughout the crop cycle from the mean EVI temporal profile by municipality. For the combined models the ECMWF calibrated variables were generated for each phenological phase of soybean. The variables selection were carried out using Stepwise method followed by regression. As results summer crop masks were generated by municipality and, comparing to official IBGE figures, reached good fitting (R² > 0,84; d > 0,95; c > 0,85) and very good spatial accuracy (Global Accuracy > 92,8% e Kappa index > 0,86) using as reference Landsat5/TM and AWiFS/IRS images. The calibration procedure of the 303 pixels of the ECMWF data over the state was done by simple linear regression models of 10 year period of data (2000-2009). All agrometeorological variables studied, except rainfall, showed high accuracy (d, MAE, RMSE) and precision (R2, r) and low trend (bias) (Es). The best fit variable was mean air temperature, followed by reference evapotranspiration and global solar radiation, with c values of 0.83; 0.81 and 0.76, respectively. The ECMWF calibration of rainfall were not significant probably due to high spatial variability of surface measurements. The soybean yields estimation obtained using the spectral models showed the worst accuracy (MAE, RMSE, MAPE) and precision (r, R²) compared to combined (spectral and agrometeorological) model approach, in agreement with the literature results that indicate better performance in yield models with the inclusion of agrometeorological data. Estimates by spectral and combined models showed no systematic error compared to official data, once Willmott agreement [d] values were, for all models, near 1, almost on the line 1:1. As conclusions, the proposed methodology for mask generation was efficient and can be used at state level scale, within the limitation of the EVI/MODIS images spatial resolution (250m). It was possible and necessary the calibration of data estimated by ECMWF model for the variables global solar radiation, reference evapotranspiration, and mean air temperature. It was not possible to calibrate rainfall data due to high spatial variability of surface data measured by meteo ground stations / Doutorado / Planejamento e Desenvolvimento Rural Sustentável / Doutor em Engenharia Agrícola
52

Un modèle spatio-temporel sémantique pour la modélisation de mobilités en milieu urbain / A conceptual and semantic modelling approach for the representation and exploration of human trajectories

Jin, Meihan 18 September 2017 (has links)
La croissance rapide et la complexité de nombreuses villes contemporaines offrent de nombreux défis de recherche pour les scientifiques à la recherche d'une meilleure compréhension des mobilités qui se produisent dans l'espace et dans le temps. A l’heure où de très grandes séries de données de trajectoires en milieu urbain sont disponibles grâce à profusion de nombreux capteurs de positionnement et de services de nombreuses et nouvelles opportunités de recherche et d’application nous sont offertes. Cependant, une bonne intégration de ces données de mobilité nécessite encore l'élaboration de cadres méthodologiques et conceptuels tout comme la mise en oeuvre de bases de données spatio-temporelles qui offriront les capacités appropriées de représentation et de manipulation des données. La recherche développée dans cette thèse introduit une modélisation conceptuelle et une approche de gestion de base de données spatio-temporelles pour représenter et analyser des trajectoires humaines dans des espaces urbains. Le modèle considère les dimensions spatiales, temporelles et sémantiques afin de tenir compte de l’ensemble des propriétés issues des informations de mobilité. Plusieurs abstractions de données de mobilité et des outils de manipulation de données sont développés et expérimentés à partir d’une large base de données de trajectoires disponibles dans la ville de Pékin. L'intérêt de l'approche est double: il montre d’une part que de larges ensembles de données de mobilité peuvent être intégrés au sein de SGBD spatiotemporels extensibles; d’autre part des outils de manipulation et d’interrogation spécifiques peuvent être dérivés à partir de fonctions intégrées au sein d’un langage d’interrogation. Le potentiel de l’approche est illustré par une série d’interrogations qui montrent comment à partir d’une large base de données de trajectoires quelques patrons de déplacements peuvent être obtenus. / Massive trajectory datasets generated in modern cities generate not only novel research opportunities but also important methodological challenges for academics and decision-makers searching for a better understanding of travel patterns in space and time. This PhD research is oriented towards the conceptual and GIS-based modeling of human displacements derived from large sets of urban trajectories. The motivation behind this study originates from the necessity to search for and explore travel patterns that emerge from citizens acting in the city. Our research introduces a conceptual modelling framework whose objective is to integrate and analyze human displacements within a GIS-based practical solution. The framework combines conceptual and logical models that represent travel trajectories of citizens moving in a given city. The whole approach has been implemented in a geographical database system, experimented in the context of transportation data, and enriched by a series of query interface manipulations and specific functions that illustrate the potential of our whole framework for urban studies. The whole framework has been experimented on top of the Geolife project and large trajectories datasets available in the city of Beijing. Overall, the findings are twofold: first, it appears that our modelling framework can appropriately act as an extensible geographical database support for the integration of large trajectory datasets; second the approach shows that several emerging human displacements can be explored from the manipulation of large urban trajectories.
53

Porovnání schématu relační databáze a struktur formátu XML / Comparison of relational database schema and XML structures

Vodňanský, Daniel January 2013 (has links)
The work deals with the relationship of the relational model and XML schema document and its technological and pragmatic aspects. It defines the theoretical field of data modeling at conceptual level and the two mentioned possible implementation models at the physical level. The aim is to answer the question when in the design and development of application or system it is appropriate to proceed with one of these models. Furthermore, this work also provides a general procedure for mapping conceptual schema into XML schema structures and solutions to problems that can come across during the mapping process. The problem is solved by analyzing two real issues - timetables of public transportation and the information system of a swimming school, formalized through a mechanism of predicate logic. Unlike most works on a similar topic this one varies in a pragmatic view on the problem - the concept of data, their origin, their target user and structuring.
54

Modelagem de dados climáticos e socioeconômicos em municípios do estado de Pernambuco utilizando análise de componentes principais (ACP).

Silva, Vicente Natanael Lima 10 April 2018 (has links)
Submitted by Biblioteca Central (biblioteca@unicap.br) on 2018-06-05T17:18:37Z No. of bitstreams: 2 vicente_natanael_lima_silva.pdf: 2871330 bytes, checksum: 1730e0371d28b2975de3c999a484a82b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-05T17:18:37Z (GMT). No. of bitstreams: 2 vicente_natanael_lima_silva.pdf: 2871330 bytes, checksum: 1730e0371d28b2975de3c999a484a82b (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES# / #2075167498588264571# / #600 / In the State of Pernambuco, as well as throughout the Northeast region of Brazil, the expressive interaction between climate elements and human activities is evident. Numerous scientific studies have already demonstrated a significant correlation between climate behavior with social, economic, cultural, etc. This work served as a case study of the application of the multivariate statistical technique of Principal Components Analysis (PCA) in the making of socioeconomic diagnoses, where the elements of the climate were used as independent variables on the socioeconomic responses (Gross Domestic Product and Municipal Development Index) Of some municipalities that presented significant development in the State of Pernambuco - Brazil, between 1999 and 2013. Even considering the climatic, socioeconomic and essential dependence of water for the economic development of the municipalities studied, the PCA showed that the socioeconomic indexes of the municipalities located in the Sertão (Petrolina and Arcoverde) will present a higher correlation with the indices of temperature and Insulation, in the Agreste and Zona da Mata (Garanhuns and Surubim) evaporation and temperatures, in the Litoral (Recife) precipitation and humidity. The PCA was also effective in allowing the removal or disposal of variables that presented low variability or were redundant because they were correlated with those of greater importance for the first two main components. Understanding the behavior of climate elements and their consequences on human activities is of fundamental importance in helping public policies to mitigate the adverse effects of environmental change. / No Estado de Pernambuco, assim como em toda a região do Nordeste do Brasil, é evidente a expressiva interação existente entre os elementos do clima e as atividades humanas. Inúmeros estudos científicos já demostraram uma significativa correlação entre o comportamento climático com os aspectos sociais, econômicos, culturais, etc. Este trabalho serviu como estudo de caso da aplicação da técnica estatística multivariada de Análise de Componentes Principais (ACP) na confecção de diagnósticos socioeconômicos, onde foram utilizados os elementos do clima como independentes sobre as variáveis respostas socioeconômicas (Produto Interno Bruto e Índice de Desenvolvimento Municipal) de alguns municípios que apresentaram expressivo desenvolvimento no Estado de Pernambuco – Brasil, entre os anos de 1999 e 2013. Mesmo considerando as diferenças climáticas, socioeconômicas e a imprescindível dependência da água para o desenvolvimento econômico dos municípios estudados, a ACP demostrou que os índices socioeconômicos dos municípios localizados no Sertão (Petrolina e Arcoverde) apresentarão maior correlação com os índices de temperaturas e Insolação, no Agreste e Zona da Mata (Garanhuns e Surubim) a evaporação e temperaturas, no Litoral (Recife) a precipitação e umidade. ACP mostrou-se também efetiva em permitir a retirada ou descarte de variáveis que apresentaram baixa variabilidade ou foram redundantes por estarem correlacionadas com as de maior importância para dois primeiros componentes principais. A compreensão do comportamento dos elementos do clima e de suas consequências sobre as atividades humanas é de fundamental importância no auxílio às políticas públicas, que visem à mitigação de efeitos adversos provocados pelas alterações ambientais.
55

Implicações funcionais de eventos de splicing alternativo no proteoma humano / Functional implications of alternative splicing in the human proteome

Fabio Passetti 16 May 2007 (has links)
A pós-genômica surgiu como um próspero campo para que as infinidades de seqüências provenientes dos projetos genoma tenham os seus significados biológicos elucidados. Um dos mecanismos descritos na literatura capaz de gerar surpreendente diversidade protéica é o splicing alternativo (AS). Próximo de 22% das proteínas com estruturas tridimensionais resolvidas por difração de raios-X ou ressonância magnética nuclear (RMN) são humanas e pouco se sabe dos efeitos de eventos de splicing alternativo em suas funções. Uma vez que estas estruturas tridimensionais (3D) protéicas humanas são de alguma forma redundantes, o conjunto de genes humanos únicos que as correspondem é muito reduzido, em torno de 1%. Hoje em dia ainda são escassos os exemplos de duas isoformas de splicing alternativo de um mesmo gene com estruturas tridimensionais experimentais disponíveis. A variedade de proteínas que este evento pode potencialmente produzir é demasiado grande para que projetos de genômica estrutural em andamento consigam determinar suas estruturas. Isto tem inviabilizado, ainda que temporariamente, estudos sobre implicações funcionais de splicing alternativo no proteoma quando se utilizando dados estruturais experimentais. Entretanto, a bioinformática possibilita estudos deste porte com base nos dados de mapeamento no genoma, tanto de transcritos como de proteínas com estrutura tridimensional (3D) determinada. Torna-se possível, então, a prospecção de genes com isoformas de AS com estruturas 3D contendo informação adicional quando comparada à isoforma de AS. Produzimos para tal finalidade uma nova metodologia para detecção de eventos de AS no transcriptoma humano utilizando matrizes binárias para cada transcrito e estrutura de proteína 3D. Selecionadas as isoformas protéicas putativas, foram construídas 73 estruturas 3D utilizando conceitos de modelagem molecular por homologia. Foram escolhidas aleatoriamente 21 isoformas de AS para simulações por dinâmicas moleculares (SDM), e que cerca de 80% destes modelos se apresentaram estruturalmente estáveis. A anotação biológica relativa a cada fragmento não inserido na seqüência da proteína devido à sua remoção no mRNA resultante do evento de AS foi obtida e mostrou que mais de 80% delas possuem algum tipo de relevância funcional para a proteína. Concluímos que, para o nosso conjunto de dados, os eventos de splicing alternativo produzem isoformas que podem atuar como dominantes negativas, antagonistas ou atenuadoras da sua atividade biológica. / The post-genomic era has emerged as one prosper field to deal with the huge amount of sequences produced by genome projects and increase the understanding of its biological meaning. One of the most surprising mechanisms capable to generate a lot of protein diversity is alternative splicing in immature mRNAs. No more than 22% of the known protein structures elucidated by X-ray diffraction or nuclear magnetic resonance (NMR) were made using human proteins and the knowledge about alternative splicing functional implications is weak. Since those human protein three-dimensional structures (3D) are redundant, the unique number of human genes represented by them is estimated around 1%. Nowadays there are only a few cases describing two isoforms that have their own protein 3D structures done experimentally. The variety that alternative splicing can produce is large enough to structural genome projects undergoing could determinate its structures, fact that have negating, at least for a while, large-scale studies about functional implications of alternative splicing using experimental data. However, bioinformatics turn possible this kind of projects using the mapping onto the genome of transcripts and the sequence of the known protein 3D structures. Using this approach we searched for alternative splicing isoforms which have at least one known protein structure with additional biological information when compared against the isoform. We have produced a new methodology for detecting alternative splicing in the human transcriptoma using binary matrices for each transcript and known 3D protein structure. After the selection of putative isoforms, there were constructed 73 3D protein using concepts of molecular modelling by homology. There were randomly selected 21 of them to the submitted to molecular dynamics simulations and 80% of them showed that they were structurally stable. The biological annotation of each non-inserted fragment due to alternative splicing shows that 80% of them have in some degree functional importance. Then, we conclude that, for our dataset, the alternative splicing events produce isoforms that can act as negative dominants, antagonists or even regulators of their biological activity.
56

Business Intelligence řešení pro společnost 1188 / Business Intelligence Solution for Company 1188

Kříž, Jan January 2015 (has links)
Cílem této diplomové práce je vytvoření Business Intelligence řešení pro společnost 1188. Na základě výsledného Business Intelligence řešení bude umožněno managementu společnosti vykonávat přesnější rozhodnutí, která se budou shodovat se strategií společnosti.
57

Tvorba datového skladu a reportovacích služeb / Creation of Data Warehouse and Reporting Services

Zduba, Andreas January 2016 (has links)
The aim of this master thesis was to design and develop decision making solution (Business Intelligence) for company Toprecepty.cz. Thanks to this solution, company management will have the ability to produce better decisions based on gained analytical information.
58

Détection d’évènements dans des environnements connectés / Event detection in connected environments

Mansour, Elio 18 November 2019 (has links)
L’intérêt croissant pour les environnements connectés (bâtiments, villes, usines intelligents) etl’évolution des réseaux de capteurs, technologies de gestion/communication de données ont ouvertla voie à des applications intéressantes et utiles qui aident les utilisateurs dans leurs tâchesquotidiennes (augmenter la productivité dans une usine, réduire la consommation d’énergie).Cependant, diverses améliorations sont encore nécessaires. Par exemple, comment améliorer lareprésentation de ces environnements complexes, dynamiques et hétérogènes. En outre, commentfaciliter l’interaction entre les utilisateurs et leurs environnements connectés et comment fournir desoutils de surveillance et de gestion de tels environnements.Dans cette thèse, nous nous concentrons sur quatre défis principaux: (i) représenter un ensemblediversifié de composants et d’éléments liés à l’environnement et à son réseau de capteurs; (ii) fournirun langage de requête qui gère les interactions utilisateur/environnement connecté (pour la définitionde l’environnement, la gestion de données, la définition d’événements); (iii) faire face à la dynamiquede l’environnement et à son évolution dans le temps; et (iv) proposer un mécanisme générique dedétection d’événements pour mieux surveiller l’environnement.Pour ce faire, nous présentons d’abord un modèle de données basé sur une ontologie qui représentedes environnements et réseaux de capteurs hybrides. Couvrant ainsi divers capteurs (statique, mobile),environnements (infrastructures, équipements) et données (scalaires, multimédia). Ensuite, nousintroduisons un langage de requête que l’on pourrait utiliser pour diverses tâches (définirl’environnement connecté, la recherche d’informations, la définition d’événements, la gestion dedonnées). De plus, afin de suivre les changements d’environnement, nous fournissons un optimiseurde requêtes qui permet aux requêtes soumises de gérer la dynamique de l’environnement avant leurexécution. Enfin, nous proposons un noyau de détection d’événement qui prend en entrée lesdéfinitions d’événement et détecte les événements ciblés.Nous regroupons les modules susmentionnés dans un framework global pour la détectiond’événements dans des environnements connectés. Notre proposition est générique, extensible, etpourrait être utilisée avec différents environnements connectés tels que des bâtiments, des villes. . . / The rising interest in smart connected environments (e.g., smart buildings, cities, factories) and theevolution of sensors, data management/communication technologies have paved the way forinteresting and useful applications that help users in their every day tasks (e.g. increasing comfort,reducing energy consumption). However, various improvements are still required. For instance, howto enhance the representation of such complex, dynamic, and heterogeneous environments.Moreover, how to facilitate the interaction between users and their connected environments, and howto provide tools for environment monitoring and management.In this thesis, we focus on four main challenges: (i) representing a diverse set of components andelements related to the environment and its sensor network; (ii) providing a query language thathandles user/connected environment interactions (e.g., environment definition, data management,event definition); (iii) coping with the dynamicity of the environment and its evolution over time; and(iv) proposing a generic event detection mechanism for improved environment monitoring.To do so, we first present an ontology-based data model that represents hybrid environments/sensornetworks. Thus covering diverse sensors (e.g., static, mobile), environments (e.g., infrastructures,devices), and data (e.g., scalar, multimedia). Then, we introduce a query language that one might usefor various tasks (e.g., defining the connected environment, information retrieval, event definition,data management). Furthermore, to keep up with the environment changes we provide a queryoptimizer that allows the submitted queries to cope with the dynamicity of the environment prior totheir execution. Finally, we propose an event detection core that takes event definitions as input anddetects the targeted events.We group the aforementioned modules in one global framework for event detection in connectedenvironments. Our proposal is generic, extensible, and could be used with different connectedenvironments such as buildings, cities. . .
59

Pervasive Quantied-Self using Multiple Sensors

January 2019 (has links)
abstract: The advent of commercial inexpensive sensors and the advances in information and communication technology (ICT) have brought forth the era of pervasive Quantified-Self. Automatic diet monitoring is one of the most important aspects for Quantified-Self because it is vital for ensuring the well-being of patients suffering from chronic diseases as well as for providing a low cost means for maintaining the health for everyone else. Automatic dietary monitoring consists of: a) Determining the type and amount of food intake, and b) Monitoring eating behavior, i.e., time, frequency, and speed of eating. Although there are some existing techniques towards these ends, they suffer from issues of low accuracy and low adherence. To overcome these issues, multiple sensors were utilized because the availability of affordable sensors that can capture the different aspect information has the potential for increasing the available knowledge for Quantified-Self. For a), I envision an intelligent dietary monitoring system that automatically identifies food items by using the knowledge obtained from visible spectrum camera and infrared spectrum camera. This system is able to outperform the state-of-the-art systems for cooked food recognition by 25% while also minimizing user intervention. For b), I propose a novel methodology, IDEA that performs accurate eating action identification within eating episodes with an average F1-score of 0.92. This is an improvement of 0.11 for precision and 0.15 for recall for the worst-case users as compared to the state-of-the-art. IDEA uses only a single wrist-band which includes four sensors and provides feedback on eating speed every 2 minutes without obtaining any manual input from the user. / Dissertation/Thesis / Doctoral Dissertation Computer Engineering 2019
60

Efficient Approximate OLAP Querying Over Time Series

Perera, Kasun S., Hahmann, Martin, Lehner, Wolfgang, Pedersen, Torben Bach, Thomsen, Christian 15 June 2023 (has links)
The ongoing trend for data gathering not only produces larger volumes of data, but also increases the variety of recorded data types. Out of these, especially time series, e.g. various sensor readings, have attracted attention in the domains of business intelligence and decision making. As OLAP queries play a major role in these domains, it is desirable to also execute them on time series data. While this is not a problem on the conceptual level, it can become a bottleneck with regards to query run-time. In general, processing OLAP queries gets more computationally intensive as the volume of data grows. This is a particular problem when querying time series data, which generally contains multiple measures recorded at fine time granularities. Usually, this issue is addressed either by scaling up hardware or by employing workload based query optimization techniques. However, these solutions are either costly or require continuous maintenance. In this paper we propose an approach for approximate OLAP querying of time series that offers constant latency and is maintenance-free. To achieve this, we identify similarities between aggregation cuboids and propose algorithms that eliminate the redundancy these similarities present. In doing so, we can achieve compression rates of up to 80% while maintaining low average errors in the query results.

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