Filters








490 Hits in 2.1 sec

Benchmarking Spatial Data Warehouses [chapter]

Thiago Luís Lopes Siqueira, Ricardo Rodrigues Ciferri, Valéria Cesário Times, Cristina Dutra de Aguiar Ciferri
2010 Lecture Notes in Computer Science  
Spatial data warehouses (SDW) enable analytical multidimensional queries together with spatial analysis. Mainly, three operations are related to SDW query processing performance: (i) joining large fact tables and large spatial and non-spatial dimension tables; (ii) computing one or more costly spatial predicates based on spatial ad hoc query windows; and (iii) aggregating data according to different spatial granularity levels. Several techniques to improve the query processing performance over
more » ... DW have been proposed in the literature. However, we identified the lack of a benchmark to carry out a controlled experimental evaluation of such techniques and, principally, to effectively measure the costs of the aforementioned three complex operations. In this paper, we propose a novel spatial data warehouse benchmark, called Spadawan, to provide performance evaluation environments for SDW and enable a further investigation on spatial data redundancy. The Spadawan benchmark is available at http://gbd.dc.ufscar.br/spadawan. Keywords: spatial data warehouse, benchmarking, performance evaluation, drill-down and roll-up operations. a spatial relationship, e.g. containment, such as (city)  (address). As a result, spatial OLAP (SOLAP) operations are common roll-up and drill-down extended to hold spatial predicates [5] . Also, the well-known star and snowflake schemas may be adequately adapted to support the inclusion of spatial attributes, which introduce new storage costs and might impair query processing performance [3] [6] . Mainly, three operations are related to SDW query processing performance: (i) joining large fact tables and large spatial and non-spatial dimension tables; (ii) computing one or more costly spatial predicates based on spatial ad hoc query windows; and (iii) aggregating data according to different spatial granularity levels. An example of a spatial and multidimensional query is "find out the total revenue earned by suppliers whose addresses are inside a rectangular window". This query mentions a topological relationship and a spatial ad hoc query window that was not previously stored in dimension tables. Another query may be issued to roll-up to the city granularity level by using a larger window that intersects the cities where the suppliers are located, for instance. Indices and materialized views are used to provide efficient query processing over SDW, and the requirements to evaluate their efficiency are datasets with different characteristics of data volume, data distribution and data types, as well as diverse types of query concerning their selectivity. The literature mentions benchmarks for decision support and data warehouses [7] [8] [9] , and for spatial databases [10] [11] , synthetic spatial datasets generators [12] and real spatial datasets (e.g. Tiger/Line, see http://www.census.gov/geo/www/tiger/). However, using them to evaluate SDW query processing requires several adaptations to comprise spatial roll-up and drilldown operations, for instance. Therefore, there is a lack of a SDW benchmark to carry out a controlled experimental evaluation and, principally, to effectively assess the costs of the aforementioned operations. In this paper, we propose a novel spatial data warehouse benchmark, called Spadawan, to address the query processing performance on spatial roll-up and drilldown operations using predefined spatial hierarchies over SDW. As spatial predicates, the Spadawan benchmark focuses on intersection, containment and enclosure range queries. Furthermore, it comprises redundant and non-redundant SDW schemas based on the Star Schema Benchmark (SSB) [8] . Consequently, the Spadawan benchmark provides a further spatial data redundancy investigation and comparison with a non-redundant SDW schema. This paper is organized as follows. Section 2 surveys related work. Section 3 describes the SDW schemas of the Spadawan benchmark, while Section 4 describes data loading operations according to each schema. Section 5 presents the queries of the Spadawan benchmark and their particularities. Section 6 briefly describes a case study and Section 7 concludes the paper. Related Work Benchmarks for spatial databases [10] [11] are not aimed at assessing the efficiency of SOLAP operations, although they focus on the spatial predicate computation. Regarding data warehouses, TPC-D is an obsolete benchmark for decision support
doi:10.1007/978-3-642-15105-7_4 fatcat:qkkaesenhfa2jgqvuqt7jrqxxi

Querying data warehouses efficiently using the Bitmap Join Index OLAP Tool

Anderson Chaves Carniel, Thiago Luís Lopes Siqueira
2012 CLEI Electronic Journal  
Data warehouse and OLAP are core aspects of business intelligence environments, since the former store integrated and time-variant data, while the latter enables multidimensional queries, visualization and analysis. The bitmap join index has been recognized as an efficient mechanism to speed up queries over data warehouses. However, existing OLAP tools does not use strictly this index to improve the performance of query processing. In this paper, we introduce the BJIn OLAP Tool to efficiently
more » ... rform OLAP queries over data warehouses, such as roll-up, drill-down, slice-and-dice and pivoting, by employing the bitmap join index. The BJIn OLAP Tool was implemented and tested through a performance evaluation to assess its efficiency and to corroborate the feasibility of adopting the bitmap join index to execute OLAP queries. The performance results reported that our BJIn OLAP Tool provided a performance gain that ranged from 31% up to 97% if compared to existing solutions regarding the query processing. Our tool has proven not only to efficiently process queries, but also to process OLAP operations on the server and client sides, for different volumes of data and taking into account different operating systems. Besides, it provides a reasonable use of the main memory and enables new rows to be appended to bitmap join indices.
doi:10.19153/cleiej.15.2.7 fatcat:ibrfurd6bzexjkxjrwzk7simf4

The impact of spatial data redundancy on SOLAP query performance

Thiago Luís Lopes Siqueira, Cristina Dutra de Aguiar Ciferri, Valéria Cesário Times, Anjolina Grisi de Oliveira, Ricardo Rodrigues Ciferri
2009 Journal of the Brazilian Computer Society  
Time (s) Disk Accesses Time Reduction Star-join Time Reduction SB-index City 229.11 511 91.74% 15.69% Nation 507.41 57 85.29% 56.93% Region 1214.93 36 80.41% 73.71% Siqueira  ... 
doi:10.1590/s0104-65002009000200003 fatcat:mfqxicoe5jevrma7qwv63pexiq

The impact of spatial data redundancy on SOLAP query performance

Thiago Luís Lopes Siqueira, Cristina Dutra de Aguiar Ciferri, Valéria Cesário Times, Anjolina Grisi de Oliveira, Ricardo Rodrigues Ciferri
2009 Journal of the Brazilian Computer Society  
Time (s) Disk Accesses Time Reduction Star-join Time Reduction SB-index City 229.11 511 91.74% 15.69% Nation 507.41 57 85.29% 56.93% Region 1214.93 36 80.41% 73.71% Siqueira  ... 
doi:10.1007/bf03194499 fatcat:4kct6vsnu5djhfeixqkbckr5m4

Effect of tocilizumab on clinical outcomes at 15 days in patients with severe or critical coronavirus disease 2019: randomised controlled trial

Viviane C Veiga, João A G G Prats, Danielle L C Farias, Regis G Rosa, Leticia K Dourado, Fernando G Zampieri, Flávia R Machado, Renato D Lopes, Otavio Berwanger, Luciano C P Azevedo, Álvaro Avezum, Thiago C Lisboa (+25 others)
2021 BMJ (Clinical Research Edition)  
To determine whether tocilizumab improves clinical outcomes for patients with severe or critical coronavirus disease 2019 (covid-19). Randomised, open label trial. Nine hospitals in Brazil, 8 May to 17 July 2020. Adults with confirmed covid-19 who were receiving supplemental oxygen or mechanical ventilation and had abnormal levels of at least two serum biomarkers (C reactive protein, D dimer, lactate dehydrogenase, or ferritin). The data monitoring committee recommended stopping the trial
more » ... after 129 patients had been enrolled, because of an increased number of deaths at 15 days in the tocilizumab group. Tocilizumab (single intravenous infusion of 8 mg/kg) plus standard care (n=65) versus standard care alone (n=64). The primary outcome, clinical status measured at 15 days using a seven level ordinal scale, was analysed as a composite of death or mechanical ventilation because the assumption of odds proportionality was not met. A total of 129 patients were enrolled (mean age 57 (SD 14) years; 68% men) and all completed follow-up. All patients in the tocilizumab group and two in the standard care group received tocilizumab. 18 of 65 (28%) patients in the tocilizumab group and 13 of 64 (20%) in the standard care group were receiving mechanical ventilation or died at day 15 (odds ratio 1.54, 95% confidence interval 0.66 to 3.66; P=0.32). Death at 15 days occurred in 11 (17%) patients in the tocilizumab group compared with 2 (3%) in the standard care group (odds ratio 6.42, 95% confidence interval 1.59 to 43.2). Adverse events were reported in 29 of 67 (43%) patients who received tocilizumab and 21 of 62 (34%) who did not receive tocilizumab. In patients with severe or critical covid-19, tocilizumab plus standard care was not superior to standard care alone in improving clinical outcomes at 15 days, and it might increase mortality. ClinicalTrials.gov NCT04403685.
doi:10.1136/bmj.n84 pmid:33472855 pmcid:PMC7815251 fatcat:4m4lq2e3pfhi5dheyntslezem4

Elas: introdução à engenharia da computação e além

Thiago Luís Lopes Siqueira
2020 Anais do Women in Information Technology (WIT 2020)   unpublished
"Elas" é um conjunto de intervenções educacionais e de apoio a mulheres no ensino superior em Computação. As intervenções incidem tanto nas atividades curriculares (aula de um componente curricular) quanto nas extracurriculares (mesa-redonda e evento) do curso de bacharelado em Engenharia de Computação. Neste artigo são descritas as intervenções e relatadas as experiências. Em particular, os relatos se referem a uma turma ingressante no primeiro ano de oferecimento do curso.
doi:10.5753/wit.2020.11272 fatcat:vxy2hqjbt5c5vmwxht3d34olja

Revisores que colaboraram no ano de 2016

* * *
2016 Revista Brasileira de Odontologia  
Silva -SP Renata Tucci -RJ Renata Ximenes Lins -RJ Ricardo Machado -PR Roberto Prado -RJ Rubens Spin-Neto -Dinamarca Ruth Tramontani Ramos -RJ Saulo Leonardo Sousa Melo -EUA Sigmar de Mello Rode -SP Thiago  ...  Oliveira -EUA Índia Olinta de Azevedo Queiroz -SP Isis Andréa Venturini Pola Poiate -RJ Issis Virgina Luque Martinez -Chile João Carlos Ramos -Portugal José de Albuquerque Calasans-Maia -RJ José Freitas Siqueira  ... 
doi:10.18363/rbo.v73n4.p.353 fatcat:qjpet7qtqfbj5gxrll3z2mlfue

Relatório de pareceristas da Revista de Sociologia e Política em 2012

2012 Revista de Sociologia e Política  
Ribeiro (UFMG) ad hoc Luis Felipe Miguel (UnB) Luis Fernando Ayerbe (Unesp) ad hoc Luiz Daniel Jatobá França (UnB) ad hoc Luiz Felipe Brandão Osório (UFRJ) ad hoc Luiz Paulo Rouanet (UFSJ) ad hoc Marcelo  ...  (UFPA) ad hoc Ednaldo Ribeiro (UEM) ad hoc Eduardo Lopes Cabral Maia (UFSM) ad hoc Eduardo R.  ... 
doi:10.1590/s0104-44782012000400015 fatcat:uaqqvkkehregnjxryeskuymzui

Expediente

Rubens Elias da Silva
2019 REVISTA CIÊNCIAS DA SOCIEDADE  
Pérola do Maicá, em Santarém Pará Wandicleia Lopes De Sousa, Leila De Fátima De Oliveira Monte, Rubens Elias Da Silva e Thiago Almeida Vieira ARTIGOS ORIGINAIS 162 Territórios de atenção à saúde: dinâmicas  ...  CIÊNCIAS DA SOCIEDADE Designer, Diagramação e Editoração eletrônica Ronilson dos Santos Bezerra Revisão Adailson Viana Soares Manuel Benjamin Monteiro Liberal Sousa Fotografia e Arte de capa Luis  ... 
doi:10.30810/rcs.v2i4.899 fatcat:2ufldsoocvfctoq2whc75fyd7m

Vol.14, Nº 4 - outubro/dezembro 2015

Henrique Cordeiro Martins, Cid Gonçalves Filho, Luiz Claudio Vieira de Oliveira
2015 Faces: Revista de Administração  
Os artigos que compõem este número são: Efeito subprime na distribuição de dividendos em Portugal Luís António Gomes Almeida, Fernando Oliveira Tavares, Elisabeth Teixeira Pereira Posicionamento estratégico  ...  Barros, Israel José dos Santos Felipe Características do trabalho valorizadas por trabalhadoras de diferentes faixas etárias Patrícia Moreira da Rocha Amaral de Souza,Ana Luiza Szuchmacher Verissimo Lopes  ...  , Adriana Victoria Garibaldi de Hilal Motivation and human reliability: an analysis of individual perception Charles Santos Batista, Jair Nascimento Santos The process of creating shared value Siqueira  ... 
doaj:ead3cc24e10441dea07dfa43b27a662d fatcat:y2xw2luyw5fofbkt3zrhlrfwra

Sumário

I WCIDS
2017 Cadernos Ibero-americanos de Direito Sanitário  
Lopes Cardoso Campos 199-207 Educação em saúde na escola: experiência exitosa na prevenção das infecções sexualmente transmissíveis Raylam Rodrigues da Silva, Murilo Lopes, Patricio Almeida 208  ...  saúde: notas sobre o contributo de Michel Foucault para uma visão das práticas de saúde pública Perfil de internações pediátricas por condições sensíveis à atenção primária em um hospital infantil de São Luís  ... 
doi:10.17566/ciads.v6i0.454 fatcat:yeofgwghzfgshkyvmjogh5oqjy

Créditos

Felipe Cordeiro
2019 Em Tese  
Rodrigues INCÊNDIOS: UMA TRAGÉDIA CONTEMPORÂNEA Richard Bertolin de Oliveira Alberto Ferreira da Rocha Junior A HISTÓRIA DO BRASIL COMO UM POT-POURRI ANÁRQUICO: ANÁLISE DO ESPETÁCULO À TARDINHA NO OCIDENTE Thiago  ...  Figueiredo Geison Almeida Gustavo Moreira Alves Henrique Verthenko José Otaviano Mata Machado Júlia Guimarães Júlia Morena Costa Laísa Marra Lisa Vasconcellos Lorenza Guimarães Luciana Sousa Luís  ... 
doi:10.17851/1982-0739.24.1.1-6 fatcat:sod4fo7xsrhjde4dqja7hbi6fi

APRESENTAÇÃO

Leonor Lopes Fávero, Thiago Zilio Passerini, Andréa Pisan Soares Aguiar
2021 VERBUM CADERNOS DE PÓS-GRADUAÇÃO ISSN 2316-3267  
Apresentação do dossiê "História das Ideias Linguísticas" Leonor Lopes Fávero -PUC-SP Thiago Zilio-Passerini -PUC-SP O presente número de Verbum -Cadernos de pós-graduação reúne, na seção temática, artigos  ...  Ainda da mesma seção, consta o artigo "Estudo da Grammatica Analytica e Explicativa de Língua Portuguesa (Pardal e Ortiz -1884)" da Profª Drª Leonor Lopes Fávero, livre-docente em Semiótica e Linguística  ...  do jesuíta Luís Rodrigues, datada de 1563.  ... 
doi:10.23925/2316-3267.2021v10i3p2-6 fatcat:52mrgsg6bbg6xllwq5n4anyad4

CAPA, CONTRACAPA, FICHA CATALOGRÁFICA, SUMÁRIO - VOLUME 9, N. 1, DA REVISTA REAMEC

Dailson Evangelista Costa, Marcel Thiago Damasceno Ribeiro
2021 Revista REAMEC  
CONCEPTS: AN EXPERIENCE WITH HIGH SCHOOL STUDENTS Jadson de Souza Conceição ANÁLISE COMBINATÓRIA: METODOLOGIA DE APOIO AO e21015 PROFESSOR COMBINATORIAL ANALYSIS: TEACHER SUPPORT METHODOLOGY Antonio Luís  ...  PROTAGONISMO DE ESTUDANTES DO ENSINO MÉDIO PARA e21009 UMA EDUCAÇÃO SEXUAL EFICIENTE E APRAZÍVEL THE PROTAGONISM OF HIGH SCHOOL STUDENTS FOR EFFICIENT AND ENJOYABLE SEX EDUCATION Iana Marassi dos Santos, Edna Lopes  ... 
doi:10.26571/reamec.v9i1.12296 doaj:768b016b3bcc4741b4139bed486b2770 fatcat:v4gq4jpqpndtpomqxt7pow7p6q

Expediente e Nota Editorial

Luciano Rocha da Penha
2016 InterEspaço  
Thiago Canettieri, no artigo sobre a epistemologia da Geografia, discute a preocupação para se entender o objeto de estudo da ciência geográfica na atualidade a partir da abordagem marxista nas ópticas  ...  Corrêa Santos (UEPA), Waldemir Lima Santos (UFAC), Zulimar Márita Ribeiro Rodrigues (UFMA/São Luís)  ... 
doaj:07e53c00b9384ca88fbfe995a3ce7ae5 fatcat:rpieitzn3jbutfbolu5aa6miiq
« Previous Showing results 1 — 15 out of 490 results