[1] Webpage, “Worldometers: Real Time World Statistics,” 2022. https://www.worldometers.info/coronavirus/?zarsrc=130.
[2] U.S. CDC, “CDC COVID Data Tracker,” U.S. Centers for Disease Control and Prevention, 2022. https://covid.cdc.gov/covid-data-tracker/#datatracker-home.
[3] X. Wang, S. Hegde, C. Son, B. Keller, A. Smith, and F. Sasangohar, “Investigating mental health of US college students during the COVID-19 pandemic: Cross-sectional survey study,” J. Med. Internet Res., vol. 22, no. 9, p. e22817, Sep. 2020, doi: 10.2196/22817.
[4] A. Zandifar and R. Badrfam, “Iranian mental health during the COVID-19 epidemic,” Asian Journal of Psychiatry, vol. 51. Elsevier B.V., p. 101990, Jun. 2020, doi: 10.1016/j.ajp.2020.101990.
[5] A. Rafea and N. A. Gaballah, “Topic Detection Approaches in Identifying Topics and Events from Arabic Corpora,” Procedia Comput. Sci., vol. 142, pp. 270–277, 2018, doi: 10.1016/j.procs.2018.10.492.
[6] F. Atefeh and W. Khreich, “A survey of techniques for event detection in Twitter,” Comput. Intell., vol. 31, no. 1, pp. 133–164, Feb. 2015, doi: 10.1111/coin.12017.
[7] M. Hasan, M. A. Orgun, and R. Schwitter, “A survey on real-time event detection from the Twitter data stream,” J. Inf. Sci., vol. 44, no. 4, pp. 443–463, 2018, doi: 10.1177/0165551517698564.
[8] R. Ibrahim, A. Elbagoury, M. S. Kamel, and F. Karray, “Tools and approaches for topic detection from Twitter streams: survey,” Knowl. Inf. Syst., vol. 54, no. 3, pp. 511–539, 2018, doi: 10.1007/s10115-017-1081-x.
[9] Z. Mottaghinia, M.-R. Feizi-Derakhshi, L. Farzinvash, and P. Salehpour, “A review of approaches for topic detection in Twitter,” J. Exp. Theor. Artif. Intell., pp. 1–27, Jun. 2020, doi: 10.1080/0952813X.2020.1785019.
[10] M. Asgari-Chenaghlu, N. Nikzad-Khasmakhi, and S. Minaee, “Covid-Transformer: Detecting Trending Topics on Twitter Using Universal Sentence Encoder,” Sep. 2020, [Online]. Available: http://arxiv.org/abs/2009.03947.
[11] S. R. Nayak, D. R. Nayak, U. Sinha, V. Arora, and R. B. Pachori, “Application of deep learning techniques for detection of COVID-19 cases using chest X-ray images: A comprehensive study,” Biomed. Signal Process. Control, vol. 64, p. 102365, Feb. 2021, doi: 10.1016/j.bspc.2020.102365.
[12] M. Ahishali et al., “Advance Warning Methodologies for COVID-19 Using Chest X-Ray Images,” IEEE Access, vol. 9, pp. 41052–41065, 2021, doi: 10.1109/ACCESS.2021.3064927.
[13] M. S. Iraji, M.-R. Feizi-Derakhshi, and J. Tanha, “COVID-19 Detection Using Deep Convolutional Neural Networks and Binary Differential Algorithm-Based Feature Selection from X-Ray Images,” Complexity, vol. 2021, pp. 1–10, Oct. 2021, doi: 10.1155/2021/9973277.
[14] V. Ravi, H. Narasimhan, C. Chakraborty, and T. D. Pham, “Deep learning-based meta-classifier approach for COVID-19 classification using CT scan and chest X-ray images,” Multimed. Syst., Jul. 2021, doi: 10.1007/s00530-021-00826-1.
[15] L. L. Wang et al., “CORD-19: The COVID-19 Open Research Dataset,” Apr. 2020, [Online]. Available: http://arxiv.org/abs/2004.10706.
[16] X. Guo, H. Mirzaalian, E. Sabir, A. Jaiswal, and W. Abd-Almageed, “CORD19STS: COVID-19 Semantic Textual Similarity Dataset,” Jul. 2020, [Online]. Available: http://arxiv.org/abs/2007.02461.
[17] S. Zong, A. Baheti, W. Xu, and A. Ritter, “Extracting COVID-19 Events from Twitter,” Jun. 2020, [Online]. Available: http://arxiv.org/abs/2006.02567.
[18] C. E. Lopez, M. Vasu, and C. Gallemore, “Understanding the perception of COVID-19 policies by mining a multilanguage Twitter dataset,” Mar. 2020, [Online]. Available: http://arxiv.org/abs/2003.10359.
[19] E. Chen, K. Lerman, and E. Ferrara, “Tracking Social Media Discourse About the COVID-19 Pandemic: Development of a Public Coronavirus Twitter Data Set,” JMIR Public Heal. Surveill., vol. 6, no. 2, p. e19273, May 2020, doi: 10.2196/19273.
[20] R. Tang et al., “Rapidly Bootstrapping a Question Answering Dataset for COVID-19,” Apr. 2020, [Online]. Available: http://arxiv.org/abs/2004.11339.
[21] D. Dimitrov et al., “TweetsCOV19 - A Knowledge Base of Semantically Annotated Tweets about the COVID-19 Pandemic,” in Proceedings of the 29th ACM International Conference on Information & Knowledge Management, Oct. 2020, pp. 2991–2998, doi: 10.1145/3340531.3412765.
[22] R. K. Gupta, A. Vishwanath, and Y. Yang, “COVID-19 Twitter Dataset with Latent Topics, Sentiments and Emotions Attributes,” 2020. http://arxiv.org/abs/2007.06954.
[23] R. Lamsal, “Design and analysis of a large-scale COVID-19 tweets dataset,” Appl. Intell., pp. 1–15, Nov. 2020, doi: 10.1007/s10489-020-02029-z.
[24] J. Samuel, G. G. M. N. Ali, M. M. Rahman, E. Esawi, and Y. Samuel, “COVID-19 Public Sentiment Insights and Machine Learning for Tweets Classification,” Information, vol. 11, no. 6, p. 314, Jun. 2020, doi: 10.3390/info11060314.
[25] H. Jelodar, Y. Wang, R. Orji, and H. Huang, “Deep Sentiment Classification and Topic Discovery on Novel Coronavirus or COVID-19 Online Discussions: NLP Using LSTM Recurrent Neural Network Approach,” IEEE J. Biomed. Heal. Informatics, pp. 1–1, Jun. 2020, doi: 10.1109/jbhi.2020.3001216.
[26] J. Xue, J. Chen, C. Chen, C. Zheng, S. Li, and T. Zhu, “Public discourse and sentiment during the COVID-19 pandemic: using Latent Dirichlet Allocation for topic modeling on Twitter,” May 2020.
[27] H. Yin, S. Yang, and J. Li, “Detecting Topic and Sentiment Dynamics Due to COVID-19 Pandemic Using Social Media,” Lect. Notes Comput. Sci. (including Subser. Lect. Notes Artif. Intell. Lect. Notes Bioinformatics), vol. 12447 LNAI, pp. 610–623, Jul. 2020, doi: 10.1007/978-3-030-65390-3_46.
[28] R. Chandrasekaran, V. Mehta, T. Valkunde, and E. Moustakas, “Topics, Trends, and Sentiments of Tweets about the COVID-19 Pandemic: Temporal Infoveillance Study,” J. Med. Internet Res., vol. 22, no. 10, p. e22624, Oct. 2020, doi: 10.2196/22624.
[29] A. Kruspe, M. Häberle, I. Kuhn, and X. X. Zhu, “Cross-language sentiment analysis of European Twitter messages during the COVID-19 pandemic,” 2020.
[30] O. Gencoglu, “Large-Scale, Language-Agnostic Discourse Classification of Tweets During COVID-19,” Mach. Learn. Knowl. Extr., vol. 2, no. 4, pp. 603–616, Nov. 2020, doi: 10.3390/make2040032.
[31] L. Li et al., “Characterizing the Propagation of Situational Information in Social Media during COVID-19 Epidemic: A Case Study on Weibo,” IEEE Trans. Comput. Soc. Syst., vol. 7, no. 2, pp. 556–562, Apr. 2020, doi: 10.1109/TCSS.2020.2980007.
[32] Q. Jiao and S. Zhang, “A Brief Survey of Word Embedding and Its Recent Development,” IAEAC 2021 - IEEE 5th Adv. Inf. Technol. Electron. Autom. Control Conf., vol. 2021, pp. 1697–1701, 2021, doi: 10.1109/IAEAC50856.2021.9390956.
[33] T. Mikolov, I. Sutskever, K. Chen, G. Corrado, and J. Dean, “Distributed Representations of Words and Phrases and their Compositionality,” Adv. Neural Inf. Process. Syst., Oct. 2013.
[34] D. Nabergoj, A. D’Alconzo, D. Valerio, and E. Štrumbelj, “Topic extraction by clustering word embeddings on short online texts,” Elektroteh. Vestnik/Electrotechnical Rev., vol. 89, no. 1–2, pp. 64–72, 2022.
[35] P. Bojanowski, E. Grave, A. Joulin, and T. Mikolov, “Enriching Word Vectors with Subword Information,” Trans. Assoc. Comput. Linguist., vol. 5, pp. 135–146, Dec. 2017, doi: 10.1162/tacl_a_00051.
[36] A. Joulin, E. Grave, P. Bojanowski, and T. Mikolov, “Bag of Tricks for Efficient Text Classification,” 2017.
[37] J. Pennington, R. Socher, and C. D. Manning, “GloVe: Global Vectors for Word Representation,” in Empirical Methods in Natural Language Processing (EMNLP), 2014, pp. 1532–1543.
[38] J. Devlin, M.-W. Chang, K. Lee, and K. Toutanova, “BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding,” in NAACL HLT 2019 - 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Oct. 2019, vol. 1, pp. 4171–4186, doi: 10.18653/v1/N19-1423.
[39] M. T. Luong, H. Pham, and C. D. Manning, “Effective approaches to attention-based neural machine translation,” in Conference Proceedings - EMNLP 2015: Conference on Empirical Methods in Natural Language Processing, Aug. 2015, pp. 1412–1421, doi: 10.18653/v1/d15-1166.
[40] C. Raffel et al., “Exploring the Limits of Transfer Learning with a Unified Text-to-Text Transformer,” 2020.
[41] A. Vaswani et al., “Attention is all you need,” in Advances in Neural Information Processing Systems, Jun. 2017, vol. 2017-Decem, pp. 5999–6009.
[42] M. Ester, H.-P. Kriegel, J. Sander, and X. Xu, “A Density-Based Algorithm for Discovering Clusters in Large Spatial Databases with Noise,” 1996.
[43] M. Ankerst, M. M. Breunig, H. P. Kriegel, and J. Sander, “OPTICS: Ordering Points to Identify the Clustering Structure,” SIGMOD Rec. (ACM Spec. Interes. Gr. Manag. Data), vol. 28, no. 2, pp. 49–60, Jun. 1999, doi: 10.1145/304181.304187.
[44] A. Y. Ng and M. I. Jordan, “On Spectral Clustering: Analysis and an algorithm,” in Advances in neural information processing systems, 2002, pp. 849–856.
[45] E. A. Patrick, “Clustering Using a Similarity Measure Based on Shared Near Neighbors,” IEEE Trans. Comput., vol. C–22, no. 11, pp. 1025–1034, 1973, doi: 10.1109/T-C.1973.223640.
[46] A. Mirzal, “Statistical Analysis of Microarray Data Clustering using NMF, Spectral Clustering, Kmeans, and GMM,” IEEE/ACM Trans. Comput. Biol. Bioinforma., vol. 19, no. 2, pp. 1173–1192, 2022, doi: 10.1109/TCBB.2020.3025486.
[47] M. Asgari-Chenaghlu, M.-R. Feizi-Derakhshi, L. Farzinvash, M.-A. Balafar, and C. Motamed, “TopicBERT: A Transformer transfer learning based memory-graph approach for multimodal streaming social media topic detection,” Aug. 2020.
[48] S. Dehghani, V. Derhami, A. M. Zare Bidoki, and M. E. Basiri, “Persian Opinion Mining based on Transfer Learning,” Tabriz J. Electr. Eng., vol. 50, no. 3, pp. 1215–1224, 2020.
[49] M. A. Z. C. S. Sharifatzadeh, “Compilation Instance Transfer and Feature-representation Transfer for Cross Project Defect Prediction,” Tabriz J. Electr. Eng., vol. 48, no. 1, pp. 101–112, 2018.
[50] S. Smith, “Coronavirus (covid19) Tweets - early April,” Kaggle.com, 2020. https://www.kaggle.com/smid80/coronavirus-covid19-tweets-early-april.
[51] S. Smith, “Coronavirus (covid19) Tweets - late April | Kaggle,” 2020. https://www.kaggle.com/smid80/coronavirus-covid19-tweets-late-april.