{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T16:27:25Z","timestamp":1776097645947,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,12]],"date-time":"2021-03-12T00:00:00Z","timestamp":1615507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"This research was supported by the MISP (Ministry of Science, ICT &amp; Future Planning), Korea, under the National Program for Excellence in SW (2017-0-00137) supervised by the IITP (Institute of Information &amp; communications Technology Planing &amp; Evaluation)","award":["(2017-0-00137)"],"award-info":[{"award-number":["(2017-0-00137)"]}]},{"name":"This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)","award":["(No. 2019R1F1A1041186)."],"award-info":[{"award-number":["(No. 2019R1F1A1041186)."]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Emotion information represents a user\u2019s current emotional state and can be used in a variety of applications, such as cultural content services that recommend music according to user emotional states and user emotion monitoring. To increase user satisfaction, recommendation methods must understand and reflect user characteristics and circumstances, such as individual preferences and emotions. However, most recommendation methods do not reflect such characteristics accurately and are unable to increase user satisfaction. In this paper, six human emotions (neutral, happy, sad, angry, surprised, and bored) are broadly defined to consider user speech emotion information and recommend matching content. The \u201cgenetic algorithms as a feature selection method\u201d (GAFS) algorithm was used to classify normalized speech according to speech emotion information. We used a support vector machine (SVM) algorithm and selected an optimal kernel function for recognizing the six target emotions. Performance evaluation results for each kernel function revealed that the radial basis function (RBF) kernel function yielded the highest emotion recognition accuracy of 86.98%. Additionally, content data (images and music) were classified based on emotion information using factor analysis, correspondence analysis, and Euclidean distance. Finally, speech information that was classified based on emotions and emotion information that was recognized through a collaborative filtering technique were used to predict user emotional preferences and recommend content that matched user emotions in a mobile application.<\/jats:p>","DOI":"10.3390\/s21061997","type":"journal-article","created":{"date-parts":[[2021,3,14]],"date-time":"2021-03-14T23:52:06Z","timestamp":1615765926000},"page":"1997","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":54,"title":["Modeling of Recommendation System Based on Emotional Information and Collaborative Filtering"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1644-1869","authenticated-orcid":false,"given":"Tae-Yeun","family":"Kim","sequence":"first","affiliation":[{"name":"National Program of Excellence in Software Center, Chosun University, Gwangju 61452, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4604-1735","authenticated-orcid":false,"given":"Hoon","family":"Ko","sequence":"additional","affiliation":[{"name":"IT Research Institute, Chosun University, Gwangju 61452, Korea"}]},{"given":"Sung-Hwan","family":"Kim","sequence":"additional","affiliation":[{"name":"National Program of Excellence in Software Center, Chosun University, Gwangju 61452, Korea"}]},{"given":"Ho-Da","family":"Kim","sequence":"additional","affiliation":[{"name":"National Program of Excellence in Software Center, Chosun University, Gwangju 61452, Korea"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"177","DOI":"10.14695\/KJSOS.2018.21.1.177","article-title":"Classification of Negative Emotions based on Arousal Score and Physiological Signals using Neural Network","volume":"21","author":"Kim","year":"2018","journal-title":"Sci. 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