22 research outputs found

    A Survey on Array Storage, Query Languages, and Systems

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    Since scientific investigation is one of the most important providers of massive amounts of ordered data, there is a renewed interest in array data processing in the context of Big Data. To the best of our knowledge, a unified resource that summarizes and analyzes array processing research over its long existence is currently missing. In this survey, we provide a guide for past, present, and future research in array processing. The survey is organized along three main topics. Array storage discusses all the aspects related to array partitioning into chunks. The identification of a reduced set of array operators to form the foundation for an array query language is analyzed across multiple such proposals. Lastly, we survey real systems for array processing. The result is a thorough survey on array data storage and processing that should be consulted by anyone interested in this research topic, independent of experience level. The survey is not complete though. We greatly appreciate pointers towards any work we might have forgotten to mention.Comment: 44 page

    IDEAS-1997-2021-Final-Programs

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    This document records the final program for each of the 26 meetings of the International Database and Engineering Application Symposium from 1997 through 2021. These meetings were organized in various locations on three continents. Most of the papers published during these years are in the digital libraries of IEEE(1997-2007) or ACM(2008-2021)

    Benchmarking access methods for time-evolving regional data

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    Large-Scale Spatial Data Management on Modern Parallel and Distributed Platforms

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    Rapidly growing volume of spatial data has made it desirable to develop efficient techniques for managing large-scale spatial data. Traditional spatial data management techniques cannot meet requirements of efficiency and scalability for large-scale spatial data processing. In this dissertation, we have developed new data-parallel designs for large-scale spatial data management that can better utilize modern inexpensive commodity parallel and distributed platforms, including multi-core CPUs, many-core GPUs and computer clusters, to achieve both efficiency and scalability. After introducing background on spatial data management and modern parallel and distributed systems, we present our parallel designs for spatial indexing and spatial join query processing on both multi-core CPUs and GPUs for high efficiency as well as their integrations with Big Data systems for better scalability. Experiment results using real world datasets demonstrate the effectiveness and efficiency of the proposed techniques on managing large-scale spatial data

    The Third NASA Goddard Conference on Mass Storage Systems and Technologies

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    This report contains copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in October 1993. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems involved. Discussion topics include the necessary use of computers in the solution of today's infinitely complex problems, the need for greatly increased storage densities in both optical and magnetic recording media, currently popular storage media and magnetic media storage risk factors, data archiving standards including a talk on the current status of the IEEE Storage Systems Reference Model (RM). Additional topics addressed System performance, data storage system concepts, communications technologies, data distribution systems, data compression, and error detection and correction

    Eight Biennial Report : April 2005 – March 2007

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    Prototype of machine learning “as a service” for CMS physics in signal vs background discrimination

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    Big volumes of data are collected and analysed by LHC experiments at CERN. The success of this scientific challenges is ensured by a great amount of computing power and storage capacity, operated over high performance networks, in very complex LHC computing models on the LHC Computing Grid infrastructure. Now in Run-2 data taking, LHC has an ambitious and broad experimental programme for the coming decades: it includes large investments in detector hardware, and similarly it requires commensurate investment in the R&D in software and com- puting to acquire, manage, process, and analyse the shear amounts of data to be recorded in the High-Luminosity LHC (HL-LHC) era. The new rise of Artificial Intelligence - related to the current Big Data era, to the technological progress and to a bump in resources democratization and efficient allocation at affordable costs through cloud solutions - is posing new challenges but also offering extremely promising techniques, not only for the commercial world but also for scientific enterprises such as HEP experiments. Machine Learning and Deep Learning are rapidly evolving approaches to characterising and describing data with the potential to radically change how data is reduced and analysed, also at LHC. This thesis aims at contributing to the construction of a Machine Learning “as a service” solution for CMS Physics needs, namely an end-to-end data-service to serve Machine Learning trained model to the CMS software framework. To this ambitious goal, this thesis work contributes firstly with a proof of concept of a first prototype of such infrastructure, and secondly with a specific physics use-case: the Signal versus Background discrimination in the study of CMS all-hadronic top quark decays, done with scalable Machine Learning techniques

    Flow time series clustering for demand pattern recognition in drinking water distribution systems: New insights about the most adequate methods

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    This study presents a proposal of clustering methodologies for demand pattern recognition using network flow data collected from a large set of drinking water distribution networks in Portugal. Most of the existing studies about clustering in flow time series rely on hierarchical or k-Means clustering algorithms with inelastic measures distances. This study explores alternative clustering algorithms, distance measures, comparison time windows, internal index metrics and clustering prototypes. The performance of the alternative clustering methodology was assessed in terms of multiple internal index metrics and the characterization of the cluster centroids. The methods with the best performance were Partition Algorithm with DTW distance, PAM prototype with 15 minutes time window and the Partition Algorithm with GAK distance, PAM prototype and 15 minutes time window because they allow a clear partition of flow time series in three clusters. The first method identifies a night consumption pattern, a typical weekend pattern and a typical working day pattern, whereas the second one identifies a pattern with small variability between night and daily consumption. To improve knowledge extraction, in terms of typical and anomalous existing patterns, additional clustering operations were performed with the flow data set that belongs to the cluster with small variability between night and daily consumption. New clusters were identified and characterized regarding weekday, geographical location, and dry months and wet months, showing that patterns associated with garden irrigation are independent of the period of the day and season of the year, which indicates an inefficient water use.Este estudo apresenta uma proposta de metodologias de clustering para reconhecimento de padrões de consumo usando um conjunto de dados de caudal coletados em redes de distribuição de água em Portugal. A maioria dos estudos existentes sobre clustering em séries temporais de caudal baseia-se em algoritmos de clustering hierárquicos ou de k-Means com medidas de distâncias inelásticas. Este estudo explora alternativas de algoritmos de clustering, medidas de distância, janelas temporais de comparação, medidas de índice interno e protótipos de clustering. O desempenho das metodologias de clustering foi avaliado em termos de medidas de índice interno e também através da caracterização dos centroides dos clusters. As metodologias com melhor desempenho foram o Algoritmo de Partição com distância DTW, protótipo PAM e janela de temporal de 15 minutos e o Algoritmo de Partição com distância GAK, protótipo PAM e janela de temporal de 15 minutos, pois permitiram a formação três clusters. O primeiro método identifica um padrão de consumo noturno, um padrão típico de fim-de-semana e um padrão típico de dia útil, enquanto o segundo método destaca-se por apresentar um padrão com pequena variabilidade entre o consumo noturno e diurno. Para melhorar a extração de conhecimento, operações adicionais de clustering foram realizadas ao conjunto de dados que pertence ao cluster com pequena variabilidade entre consumo noturno e diurno. Novos clusters foram identificados e caracterizados, mostrando que os padrões associados à irrigação são independentes do período do dia e da época do ano, o que indica um uso ineficiente da água

    Multi-faceted analytics of social events: Identification, representation and monitoring

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