{"id":"https://openalex.org/W2889894327","doi":"https://doi.org/10.1007/978-3-030-00671-6_21","title":"Efficient Handling of SPARQL OPTIONAL for OBDA","display_name":"Efficient Handling of SPARQL OPTIONAL for OBDA","publication_year":2018,"publication_date":"2018-01-01","ids":{"openalex":"https://openalex.org/W2889894327","doi":"https://doi.org/10.1007/978-3-030-00671-6_21","mag":"2889894327"},"language":"en","primary_location":{"id":"doi:10.1007/978-3-030-00671-6_21","is_oa":false,"landing_page_url":"https://doi.org/10.1007/978-3-030-00671-6_21","pdf_url":null,"source":{"id":"https://openalex.org/S106296714","display_name":"Lecture notes in computer science","issn_l":"0302-9743","issn":["0302-9743","1611-3349"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319900","host_organization_name":"Springer Science+Business Media","host_organization_lineage":["https://openalex.org/P4310319900","https://openalex.org/P4310319965"],"host_organization_lineage_names":["Springer Science+Business Media","Springer Nature"],"type":"book series"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Lecture Notes in Computer Science","raw_type":"book-chapter"},"type":"book-chapter","indexed_in":["crossref"],"open_access":{"is_oa":false,"oa_status":"closed","oa_url":null,"any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5010550946","display_name":"Guohui Xiao","orcid":"https://orcid.org/0000-0002-5115-4769"},"institutions":[{"id":"https://openalex.org/I171543936","display_name":"Free University of Bozen-Bolzano","ror":"https://ror.org/012ajp527","country_code":"IT","type":"education","lineage":["https://openalex.org/I171543936"]}],"countries":["IT"],"is_corresponding":false,"raw_author_name":"Guohui Xiao","raw_affiliation_strings":["KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy"],"affiliations":[{"raw_affiliation_string":"KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy","institution_ids":["https://openalex.org/I171543936"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5047265550","display_name":"Roman Kontchakov","orcid":"https://orcid.org/0000-0002-9349-9159"},"institutions":[{"id":"https://openalex.org/I98259816","display_name":"Birkbeck, University of London","ror":"https://ror.org/02mb95055","country_code":"GB","type":"education","lineage":["https://openalex.org/I124357947","https://openalex.org/I98259816"]}],"countries":["GB"],"is_corresponding":true,"raw_author_name":"Roman Kontchakov","raw_affiliation_strings":["Department of Computer Science and Information Systems, Birkbeck, University of London, London, UK"],"affiliations":[{"raw_affiliation_string":"Department of Computer Science and Information Systems, Birkbeck, University of London, London, UK","institution_ids":["https://openalex.org/I98259816"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5084080786","display_name":"Benjamin Cogrel","orcid":"https://orcid.org/0000-0002-7566-4077"},"institutions":[{"id":"https://openalex.org/I171543936","display_name":"Free University of Bozen-Bolzano","ror":"https://ror.org/012ajp527","country_code":"IT","type":"education","lineage":["https://openalex.org/I171543936"]}],"countries":["IT"],"is_corresponding":false,"raw_author_name":"Benjamin Cogrel","raw_affiliation_strings":["KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy"],"affiliations":[{"raw_affiliation_string":"KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy","institution_ids":["https://openalex.org/I171543936"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5077723508","display_name":"Diego Calvanese","orcid":"https://orcid.org/0000-0001-5174-9693"},"institutions":[{"id":"https://openalex.org/I171543936","display_name":"Free University of Bozen-Bolzano","ror":"https://ror.org/012ajp527","country_code":"IT","type":"education","lineage":["https://openalex.org/I171543936"]}],"countries":["IT"],"is_corresponding":false,"raw_author_name":"Diego Calvanese","raw_affiliation_strings":["KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy"],"affiliations":[{"raw_affiliation_string":"KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy","institution_ids":["https://openalex.org/I171543936"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5085419553","display_name":"Elena Botoeva","orcid":"https://orcid.org/0000-0001-5881-0258"},"institutions":[{"id":"https://openalex.org/I171543936","display_name":"Free University of Bozen-Bolzano","ror":"https://ror.org/012ajp527","country_code":"IT","type":"education","lineage":["https://openalex.org/I171543936"]}],"countries":["IT"],"is_corresponding":false,"raw_author_name":"Elena Botoeva","raw_affiliation_strings":["KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy"],"affiliations":[{"raw_affiliation_string":"KRDB Research Centre, Free University of Bozen-Bolzano, Bolzano, Italy","institution_ids":["https://openalex.org/I171543936"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":5,"corresponding_author_ids":["https://openalex.org/A5047265550"],"corresponding_institution_ids":["https://openalex.org/I98259816"],"apc_list":{"value":5000,"currency":"EUR","value_usd":5392},"apc_paid":null,"fwci":4.8858,"has_fulltext":false,"cited_by_count":29,"citation_normalized_percentile":{"value":0.96669817,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":90,"max":99},"biblio":{"volume":null,"issue":null,"first_page":"354","last_page":"373"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10215","display_name":"Semantic Web and Ontologies","score":0.9998999834060669,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10215","display_name":"Semantic Web and Ontologies","score":0.9998999834060669,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10317","display_name":"Advanced Database Systems and Queries","score":0.9951000213623047,"subfield":{"id":"https://openalex.org/subfields/1705","display_name":"Computer Networks and Communications"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10679","display_name":"Service-Oriented Architecture and Web Services","score":0.9936000108718872,"subfield":{"id":"https://openalex.org/subfields/1710","display_name":"Information Systems"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/sparql","display_name":"SPARQL","score":0.900675892829895},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.8918581008911133},{"id":"https://openalex.org/keywords/sql","display_name":"SQL","score":0.8083390593528748},{"id":"https://openalex.org/keywords/key","display_name":"Key (lock)","score":0.4768858253955841},{"id":"https://openalex.org/keywords/relational-database-management-system","display_name":"Relational database management system","score":0.45687049627304077},{"id":"https://openalex.org/keywords/tree","display_name":"Tree (set theory)","score":0.4292657971382141},{"id":"https://openalex.org/keywords/database","display_name":"Database","score":0.4282754361629486},{"id":"https://openalex.org/keywords/semantics","display_name":"Semantics (computer science)","score":0.41929495334625244},{"id":"https://openalex.org/keywords/relational-database","display_name":"Relational database","score":0.4103847146034241},{"id":"https://openalex.org/keywords/theoretical-computer-science","display_name":"Theoretical computer science","score":0.4063757658004761},{"id":"https://openalex.org/keywords/rdf","display_name":"RDF","score":0.40490126609802246},{"id":"https://openalex.org/keywords/semantic-web","display_name":"Semantic Web","score":0.38039228320121765},{"id":"https://openalex.org/keywords/information-retrieval","display_name":"Information retrieval","score":0.37776684761047363},{"id":"https://openalex.org/keywords/programming-language","display_name":"Programming language","score":0.3304188847541809}],"concepts":[{"id":"https://openalex.org/C41009113","wikidata":"https://www.wikidata.org/wiki/Q54871","display_name":"SPARQL","level":4,"score":0.900675892829895},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.8918581008911133},{"id":"https://openalex.org/C510870499","wikidata":"https://www.wikidata.org/wiki/Q47607","display_name":"SQL","level":2,"score":0.8083390593528748},{"id":"https://openalex.org/C26517878","wikidata":"https://www.wikidata.org/wiki/Q228039","display_name":"Key (lock)","level":2,"score":0.4768858253955841},{"id":"https://openalex.org/C24394798","wikidata":"https://www.wikidata.org/wiki/Q192588","display_name":"Relational database management system","level":3,"score":0.45687049627304077},{"id":"https://openalex.org/C113174947","wikidata":"https://www.wikidata.org/wiki/Q2859736","display_name":"Tree (set theory)","level":2,"score":0.4292657971382141},{"id":"https://openalex.org/C77088390","wikidata":"https://www.wikidata.org/wiki/Q8513","display_name":"Database","level":1,"score":0.4282754361629486},{"id":"https://openalex.org/C184337299","wikidata":"https://www.wikidata.org/wiki/Q1437428","display_name":"Semantics (computer science)","level":2,"score":0.41929495334625244},{"id":"https://openalex.org/C5655090","wikidata":"https://www.wikidata.org/wiki/Q192588","display_name":"Relational database","level":2,"score":0.4103847146034241},{"id":"https://openalex.org/C80444323","wikidata":"https://www.wikidata.org/wiki/Q2878974","display_name":"Theoretical computer science","level":1,"score":0.4063757658004761},{"id":"https://openalex.org/C147497476","wikidata":"https://www.wikidata.org/wiki/Q54872","display_name":"RDF","level":3,"score":0.40490126609802246},{"id":"https://openalex.org/C2129575","wikidata":"https://www.wikidata.org/wiki/Q54837","display_name":"Semantic Web","level":2,"score":0.38039228320121765},{"id":"https://openalex.org/C23123220","wikidata":"https://www.wikidata.org/wiki/Q816826","display_name":"Information retrieval","level":1,"score":0.37776684761047363},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.3304188847541809},{"id":"https://openalex.org/C134306372","wikidata":"https://www.wikidata.org/wiki/Q7754","display_name":"Mathematical analysis","level":1,"score":0.0},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.0},{"id":"https://openalex.org/C38652104","wikidata":"https://www.wikidata.org/wiki/Q3510521","display_name":"Computer security","level":1,"score":0.0}],"mesh":[],"locations_count":4,"locations":[{"id":"doi:10.1007/978-3-030-00671-6_21","is_oa":false,"landing_page_url":"https://doi.org/10.1007/978-3-030-00671-6_21","pdf_url":null,"source":{"id":"https://openalex.org/S106296714","display_name":"Lecture notes in computer science","issn_l":"0302-9743","issn":["0302-9743","1611-3349"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319900","host_organization_name":"Springer Science+Business Media","host_organization_lineage":["https://openalex.org/P4310319900","https://openalex.org/P4310319965"],"host_organization_lineage_names":["Springer Science+Business Media","Springer Nature"],"type":"book series"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Lecture Notes in Computer Science","raw_type":"book-chapter"},{"id":"pmh:oai:eprints.bbk.ac.uk.oai2:23954","is_oa":false,"landing_page_url":null,"pdf_url":null,"source":{"id":"https://openalex.org/S4306400466","display_name":"BIROn (Birkbeck, University of London)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I98259816","host_organization_name":"Birkbeck, University of London","host_organization_lineage":["https://openalex.org/I98259816"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"acceptedVersion","is_accepted":true,"is_published":false,"raw_source_name":null,"raw_type":"PeerReviewed"},{"id":"pmh:oai:alma.39UBZ_INST:11235166720001241","is_oa":false,"landing_page_url":"https://link.springer.com/chapter/10.1007/978-3-030-00671-6_21","pdf_url":null,"source":{"id":"https://openalex.org/S4210197018","display_name":"View","issn_l":"2688-268X","issn":["2688-268X","2688-3988"],"is_oa":false,"is_in_doaj":true,"is_core":true,"host_organization":"https://openalex.org/P4310320595","host_organization_name":"Wiley","host_organization_lineage":["https://openalex.org/P4310320595"],"host_organization_lineage_names":["Wiley"],"type":"journal"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"text"},{"id":"pmh:oai:kar.kent.ac.uk:91264","is_oa":false,"landing_page_url":"https://kar.kent.ac.uk/91264/","pdf_url":null,"source":{"id":"https://openalex.org/S4377196264","display_name":"Kent Academic Repository (University of Kent)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I20581793","host_organization_name":"University of Kent","host_organization_lineage":["https://openalex.org/I20581793"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"Conference or workshop item"}],"best_oa_location":null,"sustainable_development_goals":[],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":25,"referenced_works":["https://openalex.org/W124764031","https://openalex.org/W273449305","https://openalex.org/W1482134990","https://openalex.org/W1549064707","https://openalex.org/W1563056472","https://openalex.org/W1974068078","https://openalex.org/W1978646358","https://openalex.org/W2006519067","https://openalex.org/W2014575573","https://openalex.org/W2026344425","https://openalex.org/W2027702526","https://openalex.org/W2049578111","https://openalex.org/W2061253631","https://openalex.org/W2095664693","https://openalex.org/W2126717690","https://openalex.org/W2131785201","https://openalex.org/W2137862151","https://openalex.org/W2299775049","https://openalex.org/W2345875610","https://openalex.org/W2515258154","https://openalex.org/W2614913282","https://openalex.org/W2617512245","https://openalex.org/W2751199251","https://openalex.org/W2753439427","https://openalex.org/W4291713285"],"related_works":["https://openalex.org/W2615202182","https://openalex.org/W4206665951","https://openalex.org/W2529794967","https://openalex.org/W2904139343","https://openalex.org/W2604011835","https://openalex.org/W3139465322","https://openalex.org/W2484233589","https://openalex.org/W1575529579","https://openalex.org/W2545844851","https://openalex.org/W3022423983"],"abstract_inverted_index":null,"counts_by_year":[{"year":2025,"cited_by_count":2},{"year":2024,"cited_by_count":2},{"year":2023,"cited_by_count":1},{"year":2022,"cited_by_count":6},{"year":2021,"cited_by_count":5},{"year":2020,"cited_by_count":8},{"year":2019,"cited_by_count":2},{"year":2018,"cited_by_count":3}],"updated_date":"2026-04-05T17:49:38.594831","created_date":"2025-10-10T00:00:00"}
