<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1390-860X</journal-id>
<journal-title><![CDATA[Ingenius. Revista de Ciencia y Tecnología ]]></journal-title>
<abbrev-journal-title><![CDATA[Ingenius]]></abbrev-journal-title>
<issn>1390-860X</issn>
<publisher>
<publisher-name><![CDATA[Universidad Politécnica Salesiana]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1390-860X2021000100050</article-id>
<article-id pub-id-type="doi">10.17163/ings.n25.2021.05</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Algoritmos para el reconocimiento de estructuras de tablas]]></article-title>
<article-title xml:lang="en"><![CDATA[Algorithms for Table Structure Recognition]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Escalona Escalona]]></surname>
<given-names><![CDATA[Yosveni]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,SOLINTEC  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Brasil</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>06</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>06</month>
<year>2021</year>
</pub-date>
<numero>25</numero>
<fpage>50</fpage>
<lpage>61</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://scielo.senescyt.gob.ec/scielo.php?script=sci_arttext&amp;pid=S1390-860X2021000100050&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.senescyt.gob.ec/scielo.php?script=sci_abstract&amp;pid=S1390-860X2021000100050&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://scielo.senescyt.gob.ec/scielo.php?script=sci_pdf&amp;pid=S1390-860X2021000100050&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen Las tablas son una manera muy común de organizar y publicar datos. Por ejemplo, en el Internet se halla un enorme número de tablas publicadas en HTML integradas en documentos PDF, o que pueden ser simplemente descargadas de páginas web. Sin embargo, las tablas no siempre son fáciles de interpretar pues poseen una gran variedad de características y son organizadas en diferentes formatos. De hecho, se han desarrollado muchos métodos y herramientas para la interpretación de tablas. Este trabajo presenta la implementación de un algoritmo, basado en campos aleatorios condicionales (CRF, Conditional Random Fields), para clasificar las filas de una tabla como fila de encabezado, fila de datos y fila metadatos. La implementación se complementa con dos algoritmos para reconocer tablas en hojas de cálculo, específicamente, basados en reglas y detección de regiones. Finalmente, el trabajo describe los resultados y beneficios obtenidos por la aplicación del algoritmo para tablas HTML, obtenidas desde la web y las tablas en forma de hojas de cálculo, descargadas desde el sitio de la Agencia Nacional de Petróleo de Brasil.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract Tables are widely adopted to organize and publish data. For example, the Web has an enormous number of tables, published in HTML, embedded in PDF documents, or that can be simply downloaded from Web pages. However, tables are not always easy to interpret due to the variety of features and formats used. Indeed, a large number of methods and tools have been developed to interpreted tables. This work presents the implementation of an algorithm, based on Conditional Random Fields (CRFs), to classify the rows of a table as header rows, data rows or metadata rows. The implementation is complemented by two algorithms for table recognition in a spreadsheet document, respectively based on rules and on region detection. Finally, the work describes the results and the benefits obtained by applying the implemented algorithm to HTML tables, obtained from the Web, and to spreadsheet tables, downloaded from the Brazilian National Petroleum Agency.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Tabular Data]]></kwd>
<kwd lng="en"><![CDATA[HTML Tables]]></kwd>
<kwd lng="en"><![CDATA[Spreadsheets]]></kwd>
<kwd lng="en"><![CDATA[Conditional Random Fields]]></kwd>
<kwd lng="en"><![CDATA[Machine Learning]]></kwd>
<kwd lng="en"><![CDATA[Algorithm]]></kwd>
<kwd lng="es"><![CDATA[datos tabulados]]></kwd>
<kwd lng="es"><![CDATA[tablas HTML]]></kwd>
<kwd lng="es"><![CDATA[hoja de cálculo]]></kwd>
<kwd lng="es"><![CDATA[campos aleatorios condicionales]]></kwd>
<kwd lng="es"><![CDATA[aprendizaje automático]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[nfogather: Entity augmentation and attribute discovery by holistic matching with web tables]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Yakout]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Ganjam]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Chakrabarti]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Chaudhuri]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the 2012 ACM SIGMOD International Conference on Management of Data, ser. SIGMOD &#8217;12. New York, NY, USA: Association for Computing Machinery,]]></source>
<year>2012</year>
<page-range>97-108</page-range></nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Webtables: Exploring the power of tables on the web]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cafarella]]></surname>
<given-names><![CDATA[M. J.]]></given-names>
</name>
<name>
<surname><![CDATA[Halevy]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Wang]]></surname>
<given-names><![CDATA[D. Z.]]></given-names>
</name>
<name>
<surname><![CDATA[Zhang]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proc. VLDB Endow]]></source>
<year>2008</year>
<volume>1</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>538-49</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="">
<article-title xml:lang=""><![CDATA[Table identification and reconstruction in spreadsheets]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Koci]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Thiele]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Romero]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
<name>
<surname><![CDATA[Lehner]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
</person-group>
<source><![CDATA[dvanced Information Systems Engineering]]></source>
<year>2017</year>
<page-range>527-41</page-range></nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Recovering semantics of tables on the web]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Venetis]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Halevy]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Madhavan]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Pasca]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Shen]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
<name>
<surname><![CDATA[Miao]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proc. VLDB Endow]]></source>
<year>2011</year>
<volume>4</volume>
<numero>9</numero>
<issue>9</issue>
<page-range>528-38</page-range></nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Annotating and searching web tables using entities, types and relationships]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Limaye]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
<name>
<surname><![CDATA[Sarawagi]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Chakrabarti]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proc. VLDB Endow]]></source>
<year>2010</year>
<volume>3</volume>
<numero>1&#8211;2</numero>
<issue>1&#8211;2</issue>
<page-range>1338-47</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Generating Linked Data by Inferring the Semantics of Tables]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Varish Mulwad and A. Joshi]]></surname>
<given-names><![CDATA[T. F.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the First International Workshop on Searching and Integrating New Web Data Sources]]></source>
<year>2011</year>
</nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Unleashing tabular content to open data: A survey on pdf table extraction methods and tools]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Corrêa and P.-O. Zander]]></surname>
<given-names><![CDATA[A. S.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the 18th Annual International Conference on Digital Government Research, ser. dg.o &#8217;17. New York, NY, USA: Association for Computing Machinery]]></source>
<year>2017</year>
<page-range>54-63</page-range></nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[pdf2table: A method to extract table information from pdf files]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Yildiz]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Kaiser]]></surname>
<given-names><![CDATA[K.]]></given-names>
</name>
<name>
<surname><![CDATA[Miksch]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<source><![CDATA[pdf2table:]]></source>
<year></year>
</nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Identifying table boundaries in digital documents via sparse line detection]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Liu]]></surname>
<given-names><![CDATA[Y.]]></given-names>
</name>
<name>
<surname><![CDATA[Mitra]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Giles]]></surname>
<given-names><![CDATA[C. L.]]></given-names>
</name>
</person-group>
<source><![CDATA[CIKM &#8217;08]]></source>
<year>2008</year>
</nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Table structure recognition based on robust block segmentation]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Kieninger]]></surname>
<given-names><![CDATA[T.]]></given-names>
</name>
</person-group>
<source><![CDATA[Kieninger]]></source>
<year>1998</year>
<page-range>22-32</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Infogather+: Semantic matching and annotation of numeric and time-varying attributes in web tables]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zhang and K. Chakrabarti]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the 2013 ACM SIGMOD International Conference on Management of Data, ser. SIGMOD &#8217;13. New York, NY, USA: Association for Computing Machinery, 2013]]></source>
<year>2013</year>
<page-range>145-56</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Towards efficient and effective semantic table interpretation]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zhang]]></surname>
<given-names><![CDATA[Z.]]></given-names>
</name>
</person-group>
<source><![CDATA[he Semantic Web &#8211; ISWC 2014, P. Mika, T. Tudorache, A. Bernstein, C. Welty, C. Knoblock, D. Vrandecic, P. Groth, N. Noy, K. Janowicz, and C. Goble, Eds. Cham: Springer International Publishing]]></source>
<year>2014</year>
<page-range>487-502</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Recognition of html table structure]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Masuda and S. Tsukamoto]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
</person-group>
<source><![CDATA[Tsukamoto]]></source>
<year>2004</year>
</nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Table header detection and classification]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Fang]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<name>
<surname><![CDATA[Mitra]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
<name>
<surname><![CDATA[Tang]]></surname>
<given-names><![CDATA[Z.]]></given-names>
</name>
<name>
<surname><![CDATA[Giles]]></surname>
<given-names><![CDATA[C. L.]]></given-names>
</name>
</person-group>
<source><![CDATA[AAAI]]></source>
<year>2012</year>
</nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Table extraction using conditional random fields]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Pinto]]></surname>
<given-names><![CDATA[D.]]></given-names>
</name>
<name>
<surname><![CDATA[McCallum]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Wei]]></surname>
<given-names><![CDATA[X.]]></given-names>
</name>
<name>
<surname><![CDATA[Croft]]></surname>
<given-names><![CDATA[W. B.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the 26th Annual International ACM SIGIR Conference on Research and Development in Informaion Retrieval, ser. SIGIR &#8217;03. New York, NY, USA: Association for Computing Machinery]]></source>
<year>2003</year>
<page-range>235-42</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Detecting and recognizing tables in spreadsheets]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Doush]]></surname>
<given-names><![CDATA[I. A.]]></given-names>
</name>
<name>
<surname><![CDATA[Pontelli]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the 9th IAPR International Workshop on Document Analysis Systems, ser. DAS &#8217;10. New York, NY, USA: Association for Computing Machinery]]></source>
<year>2010</year>
<page-range>471-8</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Table recognition in spreadsheets via a graph representation]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Koci]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Thiele]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Lehner]]></surname>
<given-names><![CDATA[W.]]></given-names>
</name>
<name>
<surname><![CDATA[Romero]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
</person-group>
<source><![CDATA[2018 13th IAPR International Workshop on Document Analysis Systems (DAS)]]></source>
<year>2018</year>
<page-range>139-44</page-range></nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Conditional random fields: Probabilistic models for segmenting and labeling sequence dat]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lafferty]]></surname>
<given-names><![CDATA[J. D.]]></given-names>
</name>
<name>
<surname><![CDATA[McCallum]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Pereira]]></surname>
<given-names><![CDATA[F. C. N.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proceedings of the Eighteenth International Conference on Machine Learning, ser. ICML &#8217;01. San Francisco, CA, USA: Morgan Kaufmann Publishers Inc]]></source>
<year>2001</year>
<page-range>282-9</page-range></nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="">
<article-title xml:lang=""><![CDATA[Book review: Pattern recognition and machine learning]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Solé]]></surname>
<given-names><![CDATA[J. L.]]></given-names>
</name>
</person-group>
<source><![CDATA[Cristopher M. Bishop. Information Science and Statistics. Springer,]]></source>
<year>2007</year>
</nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="journal">
<article-title xml:lang=""><![CDATA[Schema extraction for tabular data on the web]]></article-title>
<person-group person-group-type="author">
<name>
<surname><![CDATA[Adelfio]]></surname>
<given-names><![CDATA[M. D.]]></given-names>
</name>
<name>
<surname><![CDATA[Samet]]></surname>
<given-names><![CDATA[H.]]></given-names>
</name>
</person-group>
<source><![CDATA[Proc. VLDB Endow]]></source>
<year>2013</year>
<volume>6</volume>
<numero>6</numero>
<issue>6</issue>
<page-range>421-32</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
