{"id":"https://openalex.org/W4381802989","doi":"https://doi.org/10.3390/s23135810","title":"Orientation-Independent Human Activity Recognition Using Complementary Radio Frequency Sensing","display_name":"Orientation-Independent Human Activity Recognition Using Complementary Radio Frequency Sensing","publication_year":2023,"publication_date":"2023-06-22","ids":{"openalex":"https://openalex.org/W4381802989","doi":"https://doi.org/10.3390/s23135810","pmid":"https://pubmed.ncbi.nlm.nih.gov/37447660"},"language":"en","primary_location":{"is_oa":true,"landing_page_url":"https://doi.org/10.3390/s23135810","pdf_url":"https://www.mdpi.com/1424-8220/23/13/5810/pdf?version=1687416369","source":{"id":"https://openalex.org/S101949793","display_name":"Sensors","issn_l":"1424-8220","issn":["1424-8220"],"is_oa":true,"is_in_doaj":true,"is_indexed_in_scopus":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true},"type":"article","type_crossref":"journal-article","indexed_in":["crossref","pubmed"],"open_access":{"is_oa":true,"oa_status":"gold","oa_url":"https://www.mdpi.com/1424-8220/23/13/5810/pdf?version=1687416369","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5011415266","display_name":"Muhammad Muaaz","orcid":"https://orcid.org/0000-0001-5225-1926"},"institutions":[{"id":"https://openalex.org/I200650556","display_name":"University of Agder","ror":"https://ror.org/03x297z98","country_code":"NO","type":"funder","lineage":["https://openalex.org/I200650556"]}],"countries":["NO"],"is_corresponding":true,"raw_author_name":"Muhammad Muaaz","raw_affiliation_strings":["Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway"],"affiliations":[{"raw_affiliation_string":"Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway","institution_ids":["https://openalex.org/I200650556"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5020625198","display_name":"Sahil Waqar","orcid":"https://orcid.org/0000-0003-4553-114X"},"institutions":[{"id":"https://openalex.org/I200650556","display_name":"University of Agder","ror":"https://ror.org/03x297z98","country_code":"NO","type":"funder","lineage":["https://openalex.org/I200650556"]}],"countries":["NO"],"is_corresponding":false,"raw_author_name":"Sahil Waqar","raw_affiliation_strings":["Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway"],"affiliations":[{"raw_affiliation_string":"Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway","institution_ids":["https://openalex.org/I200650556"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5042473673","display_name":"Matthias P\u00e4tzold","orcid":"https://orcid.org/0000-0002-6859-5413"},"institutions":[{"id":"https://openalex.org/I200650556","display_name":"University of Agder","ror":"https://ror.org/03x297z98","country_code":"NO","type":"funder","lineage":["https://openalex.org/I200650556"]}],"countries":["NO"],"is_corresponding":false,"raw_author_name":"Matthias P\u00e4tzold","raw_affiliation_strings":["Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway"],"affiliations":[{"raw_affiliation_string":"Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway","institution_ids":["https://openalex.org/I200650556"]}]}],"institution_assertions":[],"countries_distinct_count":1,"institutions_distinct_count":1,"corresponding_author_ids":["https://openalex.org/A5011415266"],"corresponding_institution_ids":["https://openalex.org/I200650556"],"apc_list":{"value":2400,"currency":"CHF","value_usd":2598},"apc_paid":{"value":2400,"currency":"CHF","value_usd":2598},"fwci":2.454,"has_fulltext":true,"fulltext_origin":"pdf","cited_by_count":7,"citation_normalized_percentile":{"value":0.999955,"is_in_top_1_percent":true,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":92,"max":93},"biblio":{"volume":"23","issue":"13","first_page":"5810","last_page":"5810"},"is_retracted":false,"is_paratext":false,"primary_topic":{"id":"https://openalex.org/T11038","display_name":"Advanced SAR Imaging Techniques","score":0.9986,"subfield":{"id":"https://openalex.org/subfields/2202","display_name":"Aerospace Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T11038","display_name":"Advanced SAR Imaging Techniques","score":0.9986,"subfield":{"id":"https://openalex.org/subfields/2202","display_name":"Aerospace Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11196","display_name":"Non-Invasive Vital Sign Monitoring","score":0.9984,"subfield":{"id":"https://openalex.org/subfields/2204","display_name":"Biomedical Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10326","display_name":"Indoor and Outdoor Localization Technologies","score":0.9921,"subfield":{"id":"https://openalex.org/subfields/2208","display_name":"Electrical and Electronic Engineering"},"field":{"id":"https://openalex.org/fields/22","display_name":"Engineering"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/feature","display_name":"Feature (linguistics)","score":0.43102747}],"concepts":[{"id":"https://openalex.org/C16345878","wikidata":"https://www.wikidata.org/wiki/Q107472979","display_name":"Orientation (vector space)","level":2,"score":0.71033585},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6899035},{"id":"https://openalex.org/C554190296","wikidata":"https://www.wikidata.org/wiki/Q47528","display_name":"Radar","level":2,"score":0.65788645},{"id":"https://openalex.org/C100102862","wikidata":"https://www.wikidata.org/wiki/Q2625855","display_name":"Bistatic radar","level":4,"score":0.538011},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.5222605},{"id":"https://openalex.org/C2778559676","wikidata":"https://www.wikidata.org/wiki/Q1334213","display_name":"Doppler radar","level":3,"score":0.5159591},{"id":"https://openalex.org/C62649853","wikidata":"https://www.wikidata.org/wiki/Q199687","display_name":"Remote sensing","level":1,"score":0.46944854},{"id":"https://openalex.org/C142757262","wikidata":"https://www.wikidata.org/wiki/Q76436","display_name":"Doppler effect","level":2,"score":0.45282915},{"id":"https://openalex.org/C134406370","wikidata":"https://www.wikidata.org/wiki/Q832005","display_name":"Radar engineering details","level":4,"score":0.44613603},{"id":"https://openalex.org/C2776401178","wikidata":"https://www.wikidata.org/wiki/Q12050496","display_name":"Feature (linguistics)","level":2,"score":0.43102747},{"id":"https://openalex.org/C59584813","wikidata":"https://www.wikidata.org/wiki/Q1029234","display_name":"Continuous-wave radar","level":4,"score":0.42617047},{"id":"https://openalex.org/C31972630","wikidata":"https://www.wikidata.org/wiki/Q844240","display_name":"Computer vision","level":1,"score":0.41819704},{"id":"https://openalex.org/C153180895","wikidata":"https://www.wikidata.org/wiki/Q7148389","display_name":"Pattern recognition (psychology)","level":2,"score":0.33411932},{"id":"https://openalex.org/C10929652","wikidata":"https://www.wikidata.org/wiki/Q7279985","display_name":"Radar imaging","level":3,"score":0.26484975},{"id":"https://openalex.org/C76155785","wikidata":"https://www.wikidata.org/wiki/Q418","display_name":"Telecommunications","level":1,"score":0.23454341},{"id":"https://openalex.org/C205649164","wikidata":"https://www.wikidata.org/wiki/Q1071","display_name":"Geography","level":0,"score":0.13070387},{"id":"https://openalex.org/C121332964","wikidata":"https://www.wikidata.org/wiki/Q413","display_name":"Physics","level":0,"score":0.09868693},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.09547478},{"id":"https://openalex.org/C41895202","wikidata":"https://www.wikidata.org/wiki/Q8162","display_name":"Linguistics","level":1,"score":0.0},{"id":"https://openalex.org/C2524010","wikidata":"https://www.wikidata.org/wiki/Q8087","display_name":"Geometry","level":1,"score":0.0},{"id":"https://openalex.org/C138885662","wikidata":"https://www.wikidata.org/wiki/Q5891","display_name":"Philosophy","level":0,"score":0.0},{"id":"https://openalex.org/C1276947","wikidata":"https://www.wikidata.org/wiki/Q333","display_name":"Astronomy","level":1,"score":0.0}],"mesh":[{"descriptor_ui":"D011825","descriptor_name":"Radar","qualifier_ui":"","qualifier_name":null,"is_major_topic":true},{"descriptor_ui":"D011846","descriptor_name":"Radio Waves","qualifier_ui":"","qualifier_name":null,"is_major_topic":true},{"descriptor_ui":"D004301","descriptor_name":"Doppler Effect","qualifier_ui":"","qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D006802","descriptor_name":"Human Activities","qualifier_ui":"","qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D006801","descriptor_name":"Humans","qualifier_ui":"","qualifier_name":null,"is_major_topic":false},{"descriptor_ui":"D009038","descriptor_name":"Motion","qualifier_ui":"","qualifier_name":null,"is_major_topic":false}],"locations_count":3,"locations":[{"is_oa":true,"landing_page_url":"https://doi.org/10.3390/s23135810","pdf_url":"https://www.mdpi.com/1424-8220/23/13/5810/pdf?version=1687416369","source":{"id":"https://openalex.org/S101949793","display_name":"Sensors","issn_l":"1424-8220","issn":["1424-8220"],"is_oa":true,"is_in_doaj":true,"is_indexed_in_scopus":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true},{"is_oa":true,"landing_page_url":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10346158","pdf_url":null,"source":{"id":"https://openalex.org/S2764455111","display_name":"PubMed Central","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_indexed_in_scopus":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":["National Institutes of Health"],"type":"repository"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true},{"is_oa":false,"landing_page_url":"https://pubmed.ncbi.nlm.nih.gov/37447660","pdf_url":null,"source":{"id":"https://openalex.org/S4306525036","display_name":"PubMed","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_indexed_in_scopus":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":["National Institutes of Health"],"type":"repository"},"license":null,"license_id":null,"version":null,"is_accepted":false,"is_published":false}],"best_oa_location":{"is_oa":true,"landing_page_url":"https://doi.org/10.3390/s23135810","pdf_url":"https://www.mdpi.com/1424-8220/23/13/5810/pdf?version=1687416369","source":{"id":"https://openalex.org/S101949793","display_name":"Sensors","issn_l":"1424-8220","issn":["1424-8220"],"is_oa":true,"is_in_doaj":true,"is_indexed_in_scopus":true,"is_core":true,"host_organization":"https://openalex.org/P4310310987","host_organization_name":"Multidisciplinary Digital Publishing Institute","host_organization_lineage":["https://openalex.org/P4310310987"],"host_organization_lineage_names":["Multidisciplinary Digital Publishing Institute"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true},"sustainable_development_goals":[{"score":0.77,"display_name":"Peace, justice, and strong institutions","id":"https://metadata.un.org/sdg/16"}],"grants":[{"funder":"https://openalex.org/F4320323299","funder_display_name":"Norges Forskningsr\u00e5d","award_id":"300638"}],"datasets":[],"versions":[],"referenced_works_count":44,"referenced_works":["https://openalex.org/W2139212933","https://openalex.org/W2146194630","https://openalex.org/W2147517352","https://openalex.org/W2242223225","https://openalex.org/W2330328119","https://openalex.org/W2518968691","https://openalex.org/W2594230123","https://openalex.org/W2602548784","https://openalex.org/W2736707111","https://openalex.org/W2783961853","https://openalex.org/W2793554752","https://openalex.org/W2794401018","https://openalex.org/W2886672175","https://openalex.org/W2887191090","https://openalex.org/W2899145720","https://openalex.org/W2901295840","https://openalex.org/W2942065897","https://openalex.org/W2946093721","https://openalex.org/W2990006904","https://openalex.org/W3003646123","https://openalex.org/W3028008698","https://openalex.org/W3038200748","https://openalex.org/W3039610325","https://openalex.org/W3083822387","https://openalex.org/W3083870581","https://openalex.org/W3088179323","https://openalex.org/W3111396112","https://openalex.org/W3113920925","https://openalex.org/W3131883848","https://openalex.org/W3179595057","https://openalex.org/W3192376676","https://openalex.org/W3214232625","https://openalex.org/W3216847402","https://openalex.org/W4205647331","https://openalex.org/W4205848449","https://openalex.org/W4210553182","https://openalex.org/W4210974251","https://openalex.org/W4213253019","https://openalex.org/W4214685247","https://openalex.org/W4214857016","https://openalex.org/W4224072860","https://openalex.org/W4225324732","https://openalex.org/W4283705653","https://openalex.org/W4285300395"],"related_works":["https://openalex.org/W4380451819","https://openalex.org/W3080858538","https://openalex.org/W3012040388","https://openalex.org/W2569610252","https://openalex.org/W2548354930","https://openalex.org/W2541915404","https://openalex.org/W2387710128","https://openalex.org/W2387210280","https://openalex.org/W2165657214","https://openalex.org/W2125716714"],"abstract_inverted_index":{"RF":[0,79,227],"sensing":[1,80,228],"offers":[2],"an":[3,125,194,231],"unobtrusive,":[4],"user-friendly,":[5],"and":[6,13,99,140,159,163,165,178,252],"privacy-preserving":[7],"method":[8],"for":[9],"detecting":[10],"accidental":[11],"falls":[12],"recognizing":[14],"human":[15,29,70,97,186,196],"activities.":[16,30,71,187],"Contemporary":[17],"RF-based":[18],"HAR":[19,91,251],"systems":[20,92],"generally":[21],"employ":[22],"a":[23,32,41,44,61,77,104,179,246],"single":[24,33,62,88,248],"monostatic":[25,34,63,89,117,249],"radar":[26,35,64,108],"to":[27,48,56,66,93,121,173,183,238],"recognize":[28,68,95],"However,":[31],"cannot":[36],"detect":[37],"the":[38,49,53,84,132,150,156,175,242],"motion":[39],"of":[40,52,86,208,214,245],"target,":[42],"e.g.,":[43],"moving":[45,133],"person,":[46],"orthogonal":[47,120],"boresight":[50],"axis":[51],"radar.":[54],"Owing":[55],"this":[57,73],"inherent":[58,243],"physical":[59],"limitation,":[60],"fails":[65],"efficiently":[67],"orientation-independent":[69,96,185,195],"In":[72],"work,":[74],"we":[75,192],"present":[76],"complementary":[78,226],"approach":[81,102,229],"that":[82,110,218],"overcomes":[83],"limitation":[85],"existing":[87],"radar-based":[90,250],"robustly":[94],"activities":[98,217],"falls.":[100],"Our":[101],"used":[103,193],"distributed":[105],"mmWave":[106],"MIMO":[107],"system":[109],"was":[111,200],"set":[112],"up":[113],"as":[114],"two":[115,129,136,143],"separate":[116],"radars":[118,130],"placed":[119],"each":[122],"other":[123],"in":[124,221],"indoor":[126],"environment.":[127],"These":[128],"illuminated":[131],"person":[134],"from":[135,155,202,236],"different":[137,216,222],"aspect":[138],"angles":[139],"consequently":[141],"produced":[142],"time-variant":[144],"micro-Doppler":[145,157],"signatures.":[146],"We":[147,168],"first":[148],"computed":[149],"mean":[151],"Doppler":[152],"shifts":[153],"(MDSs)":[154],"signatures":[158],"then":[160],"extracted":[161,176],"statistical":[162],"time-":[164],"frequency-domain":[166],"features.":[167],"adopted":[169],"feature-level":[170],"fusion":[171],"techniques":[172],"fuse":[174],"features":[177],"support":[180],"vector":[181],"machine":[182],"classify":[184],"To":[188],"evaluate":[189],"our":[190],"approach,":[191],"activity":[197,212],"dataset,":[198],"which":[199],"collected":[201],"six":[203],"volunteers.":[204],"The":[205,224],"dataset":[206],"consisted":[207],"more":[209],"than":[210],"1350":[211],"trials":[213],"five":[215],"were":[219],"performed":[220],"orientations.":[223],"proposed":[225],"achieved":[230],"overall":[232],"classification":[233],"accuracy":[234],"ranging":[235],"98.31":[237],"98.54%.":[239],"It":[240],"overcame":[241],"limitations":[244],"conventional":[247],"outperformed":[253],"it":[254],"by":[255],"6%.":[256]},"abstract_inverted_index_v3":null,"cited_by_api_url":"https://api.openalex.org/works?filter=cites:W4381802989","counts_by_year":[{"year":2025,"cited_by_count":1},{"year":2024,"cited_by_count":5},{"year":2023,"cited_by_count":1}],"updated_date":"2025-03-22T14:02:28.526966","created_date":"2023-06-24"}