429 research outputs found
Apache Calcite: A Foundational Framework for Optimized Query Processing Over Heterogeneous Data Sources
Apache Calcite is a foundational software framework that provides query
processing, optimization, and query language support to many popular
open-source data processing systems such as Apache Hive, Apache Storm, Apache
Flink, Druid, and MapD. Calcite's architecture consists of a modular and
extensible query optimizer with hundreds of built-in optimization rules, a
query processor capable of processing a variety of query languages, an adapter
architecture designed for extensibility, and support for heterogeneous data
models and stores (relational, semi-structured, streaming, and geospatial).
This flexible, embeddable, and extensible architecture is what makes Calcite an
attractive choice for adoption in big-data frameworks. It is an active project
that continues to introduce support for the new types of data sources, query
languages, and approaches to query processing and optimization.Comment: SIGMOD'1
Improving the Reliability of an Electric Power System by Biomass-Fueled Gas Engine
This paper shows a practice to raise the reliability of an electric power system by the
installation of distributed generation, taking gasified biomass as fuel. To calculate the reliability index,
a probabilistic load flow was used. This index is determined as the fault probability of the system.
The resolution of this probabilistic load flow combines the method of cumulants and Gram–Charlier
expansion. To achieve the reliability index, simulating a number of contingencies is required; the
greater the number of simulated contingencies, the higher the accuracy of the index obtained. This
probabilistic technique uses the random variables as starting information, so the two generators
and loads are simulated as random variables. The generators of this distributed generation are
biomass-fueled gas engines, commonly found in Spain. The simulations carried out on the IEEE
14-bus Test System, including three biomass generators, show that the inclusion of this type of
generation improves the overall reliability indices of the electrical syste
Sistema electrónico para cuantificar poblaciones de insectos voladores y evaluar atrayentes y repelentes
Número de publicación: ES2235575 A1 (01.07.2005)
También publicado como: ES2235575 B1 (01.11.2006)
Número de Solicitud: Consulta de Expedientes OEPM (C.E.O.) P200202622 (07.11.2002)Esta invención se refiere a un sistema electrónico que permite hacer una evaluación cuantitativa de la cantidad de insectos voladores que intentan atravesar una determina zona del espacio. La zona en donde se realiza el seguimiento de los insectos que intentan atravesarla es una superficie preferentemente plana, donde se ha situado una serie de electrodos conductores, conectados a una fuente de alto voltaje.
La finalidad del sistema es proporcionar, un pulso eléctrico cada vez que sea electrocutado un insecto y este pulso eléctrico tiene unas características que permiten que pueda ser aprovechado y procesado por otros sistemas electrónicos, tales como contadores, autómatas programables, microcontroladores, o ser acoplado a los buses de entrada de un ordenador.Universidad de Almerí
La formación del profesorado en las tecnologías de la información y comunicación
[Resumen] La formación en TICs! y más específicamente
en Internet de los docentes es resaltada
en muchos informes y estudios de casos
nacionales e internacionales como el factor
causal por excelencia para entender la mejor
o peor integración de las TICs en las aulas.
El hecho de que los profesores estén
familiarizados a nivel personal con el uso de
las TICs e Internet, no implica automáticamente
que sepan cómo utilizarlos con fines
pedagógicos.
Con nuestra investigación pretendemos
establecer las especificaciones de un proyecto
de red2 informática educativa del
Municipio de A Coruña dentro del programa
"Descubrir la Informática" que se viene
desarrollando cada curso educativo desde
1998. En este caso nos centramos en una de
las secciones analizadas como es la formación
del profesorado[Abstrac] The formation in Tics and more specifically in Internet of the educational ones is emphasized in many information and studies of national and international cases like the causal factor par excellence to understand best or worse integration of the Tics in the classrooms. The fact that the professors are familiarized
at personal level with the use of the TIC
and Internet, does not imply automatically
that they know how to use them with pedagogical aims. With our investigation we try to establish the specifications of a project of educative computer science network of the Municipality of A Corunna within the program "To discover the Computer science" that comes developing each educative course from 1998. In this case we were centered in one of the analyzed sections as it is the lormation
oft he teaching staf
PigReuse: A Reuse-based Optimizer for Pig Latin
Pig Latin is a popular language which is widely used for parallel processing of massive data sets. Currently, subexpressions occurring repeatedly in Pig Latin scripts are executed as many times as they appear, and the current Pig Latin optimizer does not identify reuse opportunities.We present a novel optimization approach aiming at identifying and reusing repeated subexpressions in Pig Latin scripts. Our optimization algorithm, named PigReuse, operates on a particular algebraic representation of Pig Latin scripts. PigReuse identifies subexpression merging opportunities, selects the best ones to execute based on a cost function, and reuses their results as needed in order to compute exactly the same output as the original scripts. Our experiments demonstrate the effectiveness of our approach
Practical Experiences in Web Engineering
Web Engineering is defined like a new area to propose models, techniques,
processes, architectures, etc. in order to deal correctly with the special characteristics of
the web environment. In the last years, new methodological approaches appeared in this
environment. However, Web Engineering is not often applied in industries and real pro jects. This paper presents a general vision of a web approach, named NDT (Navigational
Development Techniques) and it is focused on the study of its practical applications
Sources of ultrafine particles in Huelva industrial city
Comunicación presentada en: V Reunión Española de Ciencia y Tecnología de Aerosoles – RECTA 2011 celebrada del 27 al 29 de junio de 2011 en CIEMAT, Madrid
Building Large XML Stores in the Amazon Cloud
International audienceIt has been by now widely accepted that an increasing part of the world's interesting data is either shared through the Web or directly produced through and for Web platforms using formats like XML (structured documents). We present a scalable store for managing a large corpora of XML documents built on top of off-the-shelf cloud infrastructure. We implement different indexing strategies to evaluate a query workload over the stored documents in the cloud. Moreover, each strategy presents different trade-offs between efficiency in query answering and cost for storing the index
PAXQuery: A Massively Parallel XQuery Processor
International audienceWe present a novel approach for parallelizing the execution of queries over XML documents, implemented within our system PAXQuery. We compile a rich subset of XQuery into plans expressed in the PArallelization ConTracts (PACT) programming model. These plans are then optimized and executed in parallel by the Stratosphere system. We demonstrate the efficiency and scalability of our approach through experiments on hundreds of GB of XML data
A New Approach to the Modeling of Anisotropic Media with the Transmission Line Matrix Method
A reformulation of the Transmission Line Matrix (TLM) method is presented to model non-dispersive anisotropic media. Two TLM-based solutions to solve this problem can already be found in the literature, each one with an interesting feature. One can be considered a more conceptual approach, close to the TLM fundamentals, which identifies each TLM in Maxwell's equations with a specific line. But this simplicity is achieved at the expense of an increase in the memory storage requirements of a general situation. The second existing solution is a more powerful and general formulation that avoids this increase in memory storage. However, it is based on signal processing techniques and considerably deviates from the original TLM method, which may complicate its dissemination in the scientific community. The reformulation presented in this work exploits the benefits of both methods. On the one hand, it maintains the direct and conceptual approach of the original TLM, which may help to better understand it, allowing for its future use and improvement by other authors. On the other hand, the proposal includes an optimized treatment of the signals stored at the stub lines in order to limit the requirement of memory storage to only one accumulative term per field component, as in the original TLM versions used for isotropic media. The good behavior of the proposed algorithm when applied to anisotropic media is shown by its application to different situations involving diagonal and off-diagonal tensor properties
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