{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T19:07:04Z","timestamp":1780427224010,"version":"3.54.1"},"reference-count":66,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2021,10,8]],"date-time":"2021-10-08T00:00:00Z","timestamp":1633651200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000030","name":"Centers for Disease Control and Prevention","doi-asserted-by":"publisher","award":["1 R21OH011749-01"],"award-info":[{"award-number":["1 R21OH011749-01"]}],"id":[{"id":"10.13039\/100000030","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Pilot Projects Research Training Program of the NY and NJ Education and Research Center, National Institute for Occupational Safety and Health","award":["T42 OH 008422"],"award-info":[{"award-number":["T42 OH 008422"]}]},{"name":"GE Research","award":["NA"],"award-info":[{"award-number":["NA"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Human activity recognition has been extensively used for the classification of occupational tasks. Existing activity recognition approaches perform well when training and testing data follow an identical distribution. However, in the real world, this condition may be violated due to existing heterogeneities among training and testing data, which results in degradation of classification performance. This study aims to investigate the impact of four heterogeneity sources, cross-sensor, cross-subject, joint cross-sensor and cross-subject, and cross-scenario heterogeneities, on classification performance. To that end, two experiments called separate task scenario and mixed task scenario were conducted to simulate tasks of electrical line workers under various heterogeneity sources. Furthermore, a support vector machine classifier equipped with domain adaptation was used to classify the tasks and benchmarked against a standard support vector machine baseline. Our results demonstrated that the support vector machine equipped with domain adaptation outperformed the baseline for cross-sensor, joint cross-subject and cross-sensor, and cross-subject cases, while the performance of support vector machine equipped with domain adaptation was not better than that of the baseline for cross-scenario case. Therefore, it is of great importance to investigate the impact of heterogeneity sources on classification performance and if needed, leverage domain adaptation methods to improve the performance.<\/jats:p>","DOI":"10.3390\/s21196677","type":"journal-article","created":{"date-parts":[[2021,10,10]],"date-time":"2021-10-10T21:37:49Z","timestamp":1633901869000},"page":"6677","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Investigation of Heterogeneity Sources for Occupational Task Recognition via Transfer Learning"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1905-7328","authenticated-orcid":false,"given":"Sahand","family":"Hajifar","sequence":"first","affiliation":[{"name":"Department of Industrial & Systems Engineering, University at Buffalo, Buffalo, NY 14260, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4122-3548","authenticated-orcid":false,"given":"Saeb Ragani","family":"Lamooki","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY 14260, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4717-8378","authenticated-orcid":false,"given":"Lora A.","family":"Cavuoto","sequence":"additional","affiliation":[{"name":"Department of Industrial & Systems Engineering, University at Buffalo, Buffalo, NY 14260, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2194-5110","authenticated-orcid":false,"given":"Fadel M.","family":"Megahed","sequence":"additional","affiliation":[{"name":"Farmer School of Business, Miami University, Oxford, OH 45056, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2871-5502","authenticated-orcid":false,"given":"Hongyue","family":"Sun","sequence":"additional","affiliation":[{"name":"Department of Industrial & Systems Engineering, University at Buffalo, Buffalo, NY 14260, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Romero, D., Bernus, P., Noran, O., Stahre, J., and Fast-Berglund, \u00c5. 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