{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T06:17:19Z","timestamp":1788157039957,"version":"build-2803163510"},"reference-count":24,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,29]],"date-time":"2026-08-29T00:00:00Z","timestamp":1787961600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004735","name":"Natural Science Foundation of Hunan Province","doi-asserted-by":"publisher","award":["2025JJ50418"],"award-info":[{"award-number":["2025JJ50418"]}],"id":[{"id":"10.13039\/501100004735","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Emergency and operating procedures in nuclear power plants usually require operators to search for information, judge system states, and make control decisions across several linked interfaces. Conventional TACOM assessment quantifies the structural complexity of such procedure-guided tasks, but it does not directly show how operators visually process the task during execution. This study examined whether eye-tracking features can provide preliminary process-level evidence for TACOM-based assessment, rather than replace the TACOM framework. We extracted 25 eye-tracking features from 21 nuclear engineering graduate students while they completed 17 SGTR\/SLOCA procedure fragments in an M310 full-scope simulator. A partial least-squares regression model predicted task-level TACOM scores, with RMSE = 0.357, MAE = 0.300, and R2 = 0.538 under leave-one-task-out cross-validation. The RMSE corresponded to 18.3% of the observed TACOM range (2.070\u20134.017), and prediction was more strongly associated with observed task ranking (Spearman\u2019s rho = 0.775) than with exact linear calibration (Pearson\u2019s r = 0.750). Feature analyses suggested that fixation\u2013duration variability, fixation dwell, pupil response, gaze dynamics, and spatial sampling jointly carried TACOM-related information. Exploratory subdimension analyses further indicated that task scope was most consistently associated with fixation dwell and fixation-time proportion, whereas task uncertainty was more closely associated with pupil variability and spatial entropy. These findings suggest that eye tracking may complement TACOM by describing execution-process demands, although the evidence remains correlational and limited by the small task set, graduate student sample, and task interface variability. Future studies should validate the signatures with licensed operators, larger multi-scenario task sets, independent TACOM scoring, and step-level AOI analyses.<\/jats:p>","DOI":"10.3390\/s26175487","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T05:55:56Z","timestamp":1788155756000},"page":"5487","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Eye-Tracking Evidence for TACOM-Based Assessment of Procedural Task Complexity in a Nuclear Power Plant Full-Scope Simulator"],"prefix":"10.3390","volume":"26","author":[{"given":"Huan","family":"Xiao","sequence":"first","affiliation":[{"name":"School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"given":"Pengcheng","family":"Li","sequence":"additional","affiliation":[{"name":"Graduate School, University of South China, Hengyang 421002, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"given":"Wenming","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Nuclear Science and Technology, University of South China, Hengyang 421001, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"given":"Jiayuan","family":"He","sequence":"additional","affiliation":[{"name":"School of Nuclear Science and Technology, University of South China, Hengyang 421001, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"data-curation","vocabulary":"credit"},{"role":"software","vocabulary":"credit"}]},{"given":"Zetian","family":"Tao","sequence":"additional","affiliation":[{"name":"School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ress.2012.01.003","article-title":"Investigating the effect of communication characteristics on crew performance under the simulated emergency condition of nuclear power plants","volume":"101","author":"Park","year":"2012","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/j.ress.2006.01.007","article-title":"OPERA\u2014A human performance database under simulated emergencies of nuclear power plants","volume":"92","author":"Park","year":"2007","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"107704","DOI":"10.1016\/j.ress.2021.107704","article-title":"Investigating the Effect of Task Complexity on the Occurrence of Human Errors observed in a Nuclear Power Plant Full-Scope Simulator","volume":"214","author":"Jang","year":"2021","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1016\/j.ssci.2015.03.005","article-title":"Task complexity as a performance shaping factor: A review and recommendations in Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) adaption","volume":"76","author":"Rasmussen","year":"2015","journal-title":"Saf. Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"111685","DOI":"10.1016\/j.ress.2025.111685","article-title":"Applicability of the TACOM measure as a tool to identify a high workload task in a proceduralized task environment","volume":"266","author":"Park","year":"2026","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"107890","DOI":"10.1016\/j.ress.2021.107890","article-title":"Analysis of dependencies among performance shaping factors in human reliability analysis based on a system dynamics approach","volume":"215","author":"Liu","year":"2021","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1102","DOI":"10.1016\/j.ress.2006.03.009","article-title":"A study on the development of a task complexity measure for emergency operating procedures of nuclear power plants","volume":"92","author":"Park","year":"2007","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.1016\/j.anucene.2010.05.001","article-title":"Investigating the effect of task complexities on the response time of human operators to perform the emergency tasks of nuclear power plants","volume":"37","author":"Park","year":"2010","journal-title":"Ann. Nucl. Energy"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2962","DOI":"10.1109\/TNS.2006.882149","article-title":"A Study on the Validity of a Task Complexity Measure for Emergency Operating Procedures of Nuclear Power Plants\u2014Comparing with a Subjective Workload","volume":"53","author":"Park","year":"2006","journal-title":"IEEE Trans. Nucl. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1016\/j.ress.2014.04.027","article-title":"Investigating the TACOM measure as a general tool for quantifying the complexity of procedure guided tasks","volume":"129","author":"Park","year":"2014","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"106415","DOI":"10.1016\/j.ress.2019.03.022","article-title":"Effects of digitalization of nuclear power plant control rooms on human reliability analysis\u2014A review","volume":"194","author":"Porthin","year":"2020","journal-title":"Reliab. Eng. Syst. Saf."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"114037","DOI":"10.1016\/j.eswa.2020.114037","article-title":"Eye tracking algorithms, techniques, tools, and applications with an emphasis on machine learning and Internet of Things technologies","volume":"166","author":"Klaib","year":"2021","journal-title":"Expert Syst. Appl."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1080\/00295450.2019.1620055","article-title":"Using Artificial Neural Networks for Predicting Mental Workload in Nuclear Power Plants Based on Eye Tracking","volume":"206","author":"Wu","year":"2020","journal-title":"Nucl. Technol."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Martinez-Marquez, D., Pingali, S., Panuwatwanich, K., Stewart, R.A., and Mohamed, S. (2021). Application of Eye Tracking Technology in Aviation, Maritime, and Construction Industries: A Systematic Review. Sensors, 21.","DOI":"10.3390\/s21134289"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2335","DOI":"10.1080\/00295639.2024.2306105","article-title":"Research on Nuclear Power Plant Operational Task Complexity Assessment Method Based on Group Decision Making and Deep Learning of EEG Signals","volume":"198","author":"Zhang","year":"2024","journal-title":"Nucl. Sci. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Keskin, M., Ooms, K., Dogru, A.O., and De Maeyer, P. (2020). Exploring the Cognitive Load of Expert and Novice Map Users Using EEG and Eye Tracking. ISPRS Int. J. Geo-Inf., 9.","DOI":"10.3390\/ijgi9070429"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0003-2670(86)80028-9","article-title":"Partial least-squares regression: A tutorial","volume":"185","author":"Geladi","year":"1986","journal-title":"Anal. Chim. Acta"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/S0169-7439(01)00155-1","article-title":"PLS-regression: A basic tool of chemometrics","volume":"58","author":"Wold","year":"2001","journal-title":"Chemom. Intell. Lab. Syst."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"735","DOI":"10.1137\/0905052","article-title":"The Collinearity Problem in Linear Regression. The Partial Least Squares (PLS) Approach to Generalized Inverses","volume":"5","author":"Wold","year":"1984","journal-title":"SIAM J. Sci. Stat. Comput."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1111\/j.2517-6161.1974.tb00994.x","article-title":"Cross-Validatory Choice and Assessment of Statistical Predictions","volume":"36","author":"Stone","year":"1974","journal-title":"J. R. Stat. Soc. Ser. B Stat. Methodol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1518\/001872095779049543","article-title":"Toward a Theory of Situation Awareness in Dynamic Systems","volume":"37","author":"Endsley","year":"1995","journal-title":"Hum. Factors"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1016\/0010-0285(76)90015-3","article-title":"Eye fixations and cognitive processes","volume":"8","author":"Just","year":"1976","journal-title":"Cogn. Psychol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1583","DOI":"10.1126\/science.154.3756.1583","article-title":"Pupil diameter and load on memory","volume":"154","author":"Kahneman","year":"1966","journal-title":"Science"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"202","DOI":"10.3758\/BF03200774","article-title":"Guided Search 2.0: A revised model of visual search","volume":"1","author":"Wolfe","year":"1994","journal-title":"Psychon. Bull. Rev."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/17\/5487\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T05:59:44Z","timestamp":1788155984000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/26\/17\/5487"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,29]]},"references-count":24,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["s26175487"],"URL":"https:\/\/doi.org\/10.3390\/s26175487","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,29]]}}}