{"id":"https://openalex.org/W3156322039","doi":"https://doi.org/10.1007/s00521-021-05957-0","title":"Semi-supervised deep learning approach to break common CAPTCHAs","display_name":"Semi-supervised deep learning approach to break common CAPTCHAs","publication_year":2021,"publication_date":"2021-04-12","ids":{"openalex":"https://openalex.org/W3156322039","doi":"https://doi.org/10.1007/s00521-021-05957-0","mag":"3156322039"},"language":"en","primary_location":{"id":"doi:10.1007/s00521-021-05957-0","is_oa":false,"landing_page_url":"https://doi.org/10.1007/s00521-021-05957-0","pdf_url":null,"source":{"id":"https://openalex.org/S147897268","display_name":"Neural Computing and Applications","issn_l":"0941-0643","issn":["0941-0643","1433-3058"],"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":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Neural Computing and Applications","raw_type":"journal-article"},"type":"article","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/A5015933724","display_name":"Ond\u0159ej Bo\u0161t\u00edk","orcid":"https://orcid.org/0000-0002-7856-2084"},"institutions":[{"id":"https://openalex.org/I60587646","display_name":"Brno University of Technology","ror":"https://ror.org/03613d656","country_code":"CZ","type":"education","lineage":["https://openalex.org/I60587646"]}],"countries":["CZ"],"is_corresponding":true,"raw_author_name":"Ondrej Bostik","raw_affiliation_strings":["Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic"],"raw_orcid":"https://orcid.org/0000-0002-7856-2084","affiliations":[{"raw_affiliation_string":"Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic","institution_ids":["https://openalex.org/I60587646"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5049528087","display_name":"Karel Hor\u00e1k","orcid":"https://orcid.org/0000-0002-2280-3029"},"institutions":[{"id":"https://openalex.org/I60587646","display_name":"Brno University of Technology","ror":"https://ror.org/03613d656","country_code":"CZ","type":"education","lineage":["https://openalex.org/I60587646"]}],"countries":["CZ"],"is_corresponding":false,"raw_author_name":"Karel Horak","raw_affiliation_strings":["Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic"],"raw_orcid":"https://orcid.org/0000-0002-2280-3029","affiliations":[{"raw_affiliation_string":"Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic","institution_ids":["https://openalex.org/I60587646"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5080413801","display_name":"Luk\u00e1\u0161 Kratochv\u00edla","orcid":null},"institutions":[{"id":"https://openalex.org/I60587646","display_name":"Brno University of Technology","ror":"https://ror.org/03613d656","country_code":"CZ","type":"education","lineage":["https://openalex.org/I60587646"]}],"countries":["CZ"],"is_corresponding":false,"raw_author_name":"Lukas Kratochvila","raw_affiliation_strings":["Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic"],"raw_orcid":"https://orcid.org/0000-0001-8425-323X","affiliations":[{"raw_affiliation_string":"Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic","institution_ids":["https://openalex.org/I60587646"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5001935828","display_name":"Tom\u00e1\u0161 Zem\u010d\u00edk","orcid":null},"institutions":[{"id":"https://openalex.org/I60587646","display_name":"Brno University of Technology","ror":"https://ror.org/03613d656","country_code":"CZ","type":"education","lineage":["https://openalex.org/I60587646"]}],"countries":["CZ"],"is_corresponding":false,"raw_author_name":"Tomas Zemcik","raw_affiliation_strings":["Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic"],"raw_orcid":"https://orcid.org/0000-0003-4363-4313","affiliations":[{"raw_affiliation_string":"Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic","institution_ids":["https://openalex.org/I60587646"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5000461756","display_name":"\u0160imon Bil\u00edk","orcid":"https://orcid.org/0000-0001-8797-7700"},"institutions":[{"id":"https://openalex.org/I60587646","display_name":"Brno University of Technology","ror":"https://ror.org/03613d656","country_code":"CZ","type":"education","lineage":["https://openalex.org/I60587646"]}],"countries":["CZ"],"is_corresponding":false,"raw_author_name":"Simon Bilik","raw_affiliation_strings":["Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic"],"raw_orcid":"https://orcid.org/0000-0001-8797-7700","affiliations":[{"raw_affiliation_string":"Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, Brno, 61200, Czech Republic","institution_ids":["https://openalex.org/I60587646"]}]}],"institutions":[],"countries_distinct_count":1,"institutions_distinct_count":5,"corresponding_author_ids":["https://openalex.org/A5015933724"],"corresponding_institution_ids":["https://openalex.org/I60587646"],"apc_list":{"value":2390,"currency":"EUR","value_usd":2990},"apc_paid":null,"fwci":5.4102,"has_fulltext":false,"cited_by_count":21,"citation_normalized_percentile":{"value":0.95779281,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":90,"max":99},"biblio":{"volume":"33","issue":"20","first_page":"13333","last_page":"13343"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11800","display_name":"User Authentication and Security Systems","score":0.9998999834060669,"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"}},"topics":[{"id":"https://openalex.org/T11800","display_name":"User Authentication and Security Systems","score":0.9998999834060669,"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"}},{"id":"https://openalex.org/T11241","display_name":"Advanced Malware Detection Techniques","score":0.9894999861717224,"subfield":{"id":"https://openalex.org/subfields/1711","display_name":"Signal Processing"},"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/T11644","display_name":"Spam and Phishing Detection","score":0.9724000096321106,"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/captcha","display_name":"CAPTCHA","score":0.9606291055679321},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.8737927079200745},{"id":"https://openalex.org/keywords/artificial-intelligence","display_name":"Artificial intelligence","score":0.6517625451087952},{"id":"https://openalex.org/keywords/deep-learning","display_name":"Deep learning","score":0.5995428562164307},{"id":"https://openalex.org/keywords/denial-of-service-attack","display_name":"Denial-of-service attack","score":0.5268501043319702},{"id":"https://openalex.org/keywords/convolutional-neural-network","display_name":"Convolutional neural network","score":0.525322675704956},{"id":"https://openalex.org/keywords/classifier","display_name":"Classifier (UML)","score":0.5076719522476196},{"id":"https://openalex.org/keywords/transfer-of-learning","display_name":"Transfer of learning","score":0.4819038212299347},{"id":"https://openalex.org/keywords/machine-learning","display_name":"Machine learning","score":0.4673400819301605},{"id":"https://openalex.org/keywords/pattern-recognition","display_name":"Pattern recognition (psychology)","score":0.3413882255554199},{"id":"https://openalex.org/keywords/the-internet","display_name":"The Internet","score":0.2123117446899414},{"id":"https://openalex.org/keywords/world-wide-web","display_name":"World Wide Web","score":0.0819719135761261}],"concepts":[{"id":"https://openalex.org/C163339463","wikidata":"https://www.wikidata.org/wiki/Q484598","display_name":"CAPTCHA","level":2,"score":0.9606291055679321},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.8737927079200745},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.6517625451087952},{"id":"https://openalex.org/C108583219","wikidata":"https://www.wikidata.org/wiki/Q197536","display_name":"Deep learning","level":2,"score":0.5995428562164307},{"id":"https://openalex.org/C38822068","wikidata":"https://www.wikidata.org/wiki/Q131406","display_name":"Denial-of-service attack","level":3,"score":0.5268501043319702},{"id":"https://openalex.org/C81363708","wikidata":"https://www.wikidata.org/wiki/Q17084460","display_name":"Convolutional neural network","level":2,"score":0.525322675704956},{"id":"https://openalex.org/C95623464","wikidata":"https://www.wikidata.org/wiki/Q1096149","display_name":"Classifier (UML)","level":2,"score":0.5076719522476196},{"id":"https://openalex.org/C150899416","wikidata":"https://www.wikidata.org/wiki/Q1820378","display_name":"Transfer of learning","level":2,"score":0.4819038212299347},{"id":"https://openalex.org/C119857082","wikidata":"https://www.wikidata.org/wiki/Q2539","display_name":"Machine learning","level":1,"score":0.4673400819301605},{"id":"https://openalex.org/C153180895","wikidata":"https://www.wikidata.org/wiki/Q7148389","display_name":"Pattern recognition (psychology)","level":2,"score":0.3413882255554199},{"id":"https://openalex.org/C110875604","wikidata":"https://www.wikidata.org/wiki/Q75","display_name":"The Internet","level":2,"score":0.2123117446899414},{"id":"https://openalex.org/C136764020","wikidata":"https://www.wikidata.org/wiki/Q466","display_name":"World Wide Web","level":1,"score":0.0819719135761261}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1007/s00521-021-05957-0","is_oa":false,"landing_page_url":"https://doi.org/10.1007/s00521-021-05957-0","pdf_url":null,"source":{"id":"https://openalex.org/S147897268","display_name":"Neural Computing and Applications","issn_l":"0941-0643","issn":["0941-0643","1433-3058"],"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":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Neural Computing and Applications","raw_type":"journal-article"},{"id":"pmh:oai:dspace.vutbr.cz:11012/203005","is_oa":false,"landing_page_url":"http://hdl.handle.net/11012/203005","pdf_url":null,"source":{"id":"https://openalex.org/S4306400317","display_name":"Brno University of Technology Digital Library (Brno University of Technology)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I60587646","host_organization_name":"Brno University of Technology","host_organization_lineage":["https://openalex.org/I60587646"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"acceptedVersion","is_accepted":true,"is_published":false,"raw_source_name":"NEURAL COMPUTING & APPLICATIONS. 2021, vol. 33, issue 20, p. 13333-13343.","raw_type":"article"}],"best_oa_location":null,"sustainable_development_goals":[{"display_name":"Industry, innovation and infrastructure","id":"https://metadata.un.org/sdg/9","score":0.6299999952316284}],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":37,"referenced_works":["https://openalex.org/W112869242","https://openalex.org/W182783924","https://openalex.org/W1552934261","https://openalex.org/W1587820067","https://openalex.org/W1603565383","https://openalex.org/W1665214252","https://openalex.org/W1667580224","https://openalex.org/W1693559965","https://openalex.org/W1923586579","https://openalex.org/W1971657180","https://openalex.org/W1987153840","https://openalex.org/W1988790447","https://openalex.org/W2084062832","https://openalex.org/W2099256741","https://openalex.org/W2105523261","https://openalex.org/W2123761123","https://openalex.org/W2145204224","https://openalex.org/W2147019420","https://openalex.org/W2153601419","https://openalex.org/W2168727550","https://openalex.org/W2187250581","https://openalex.org/W2528437680","https://openalex.org/W2595089739","https://openalex.org/W2624413595","https://openalex.org/W2794632300","https://openalex.org/W2890419535","https://openalex.org/W2958415890","https://openalex.org/W2968803003","https://openalex.org/W3010472058","https://openalex.org/W3013161732","https://openalex.org/W3034439144","https://openalex.org/W3044942467","https://openalex.org/W3106430813","https://openalex.org/W3112697749","https://openalex.org/W3124132369","https://openalex.org/W3126360167","https://openalex.org/W4249622775"],"related_works":["https://openalex.org/W3134776999","https://openalex.org/W2028308373","https://openalex.org/W3183901164","https://openalex.org/W3135818718","https://openalex.org/W4290188444","https://openalex.org/W3167935049","https://openalex.org/W3003905048","https://openalex.org/W2253429366","https://openalex.org/W3127975138","https://openalex.org/W2979740303"],"abstract_inverted_index":null,"counts_by_year":[{"year":2025,"cited_by_count":2},{"year":2024,"cited_by_count":4},{"year":2023,"cited_by_count":1},{"year":2022,"cited_by_count":14}],"updated_date":"2026-03-27T05:58:40.876381","created_date":"2025-10-10T00:00:00"}