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The purpose of this study is to explore the subject structure and hidden knowledge and development of new research subjects. This research is applied from the point of purpose and type, descriptive and from the point of method, trend analysis. The population of this study is the all of articles indexed in Scopus and written by Iranian authors in the field of knowledge and information science from 1992-2019, Then take the targeted sample in 2008-2019.Data analysis tool is software R which abstract the papers were analyzed after applying pre - processing steps with Topic modeling and LDA algorithm. The result of study to identification topic development process showed Hot topics & Cold topics to identifying the process of knowledge and information science by determining the p-level (0/05) and identify alpha, beta and theta parameters. The Hot topics that have a more popularity is: Library services on Social Networks, Research Models, Social Capital, Data Base, Data Mining, Trend of Scientific Publication, Interdisciplinary Fields, Cyberspace Algorithms, Knowledge Management and Cold topic that have a less popularity is: Electronic Resources, Information management System, Search Engine, Book loan Services, Distance Library Services, E learning, E Government, Journal Evaluation Indicators, Web sources Evaluation, Digital Library. The result of this research showed that the field of knowledge and information science can growth up with globalization and new global issues and this field ability to develop and expand in data mining, artificial intelligence, semantic retrieval, information architecture, digital publishing, social networking and information technology.

: The purpose of this study is to explore the thematic trend analysis of Iranian articles in Library and Information Science based on Topic modeling (LDA) and linear regression model. The population of this study consists of 709 articles indexed in Scopus during 2008- 2009. In order to achieve the research objectives, the data were analyzed using text mining algorithms, especially LDA thematic modeling algorithms using R software. The results showed that among the extracted topics, there are topics that have high research popularity and are considered as hot topics. These topics include library services on social media, research models, social capital, medical databases, data mining, scientific production trends, interdisciplinary studies, cyberspace algorithms, knowledge management, social media studies, research approaches, and future studies. Also, topics that are less popular and are considered as cold topics include areas such as electronic resources, information management system, search engines, book loan services, distance services, e-learning, e-government, journal evaluation indicators, evaluation of web resources, and digital libraries. The results indicated that Library and Information Science research in Iran has developed in line with the growth of technologies and global topics and has established the relationship between Library and Information Science subject area and new fields of data mining, artificial intelligence, semantic retrieval, ontologies, information architecture, digital publishing, social networks, and databases. [ABSTRACT FROM AUTHOR]

Diatoms are fundamental carbon sources in a wide range of aquatic food webs and have the potential for wide application in addressing environmental change. Understanding the evolution of topics in diatom research will provide a clear and needed guide to strengthen research on diatoms. However, such an overview remains unavailable. In this study, we used Latent Dirichlet Allocation (LDA), a generative model, to identify topics and determine their trends (i.e., cold and hot topics) by analyzing the abstracts of 19,000 publications from the Web of Science that were related to diatoms during 1991−2018. A total of 116 topics were identified from a Bayesian model selection. The hot topics (diversity, environmental indicator, climate change, land use, and water quality) that were identified by LDA indicated that diatoms are increasingly used as indicators to assess water quality and identify modern climate change impacts due to intensive anthropogenic activities. In terms of cold topics (growth rate, culture growth, cell life history, copepod feeding, grazing by microzooplankton, zooplankton predation, and primary productivity) and hot topics (spatial-temporal distribution, morphology, molecular identification, gene expression, and review), we determined that basic studies on diatoms have decreased and that studies tend to be more comprehensive. This study notes that future directions in diatom research will be closely associated with the application of diatoms in environmental management and climate change to cope with environmental challenges, and more comprehensive issues related to diatoms should be considered.

Diatoms are fundamental carbon sources in a wide range of aquatic food webs and have the potential for wide application in addressing environmental change. Understanding the evolution of topics in diatom research will provide a clear and needed guide to strengthen research on diatoms. However, such an overview remains unavailable. In this study, we used Latent Dirichlet Allocation (LDA), a generative model, to identify topics and determine their trends (i.e., cold and hot topics) by analyzing the abstracts of 19,000 publications from the Web of Science that were related to diatoms during 1991–2018. A total of 116 topics were identified from a Bayesian model selection. The hot topics (diversity, environmental indicator, climate change, land use, and water quality) that were identified by LDA indicated that diatoms are increasingly used as indicators to assess water quality and identify modern climate change impacts due to intensive anthropogenic activities. In terms of cold topics (growth rate, culture growth, cell life history, copepod feeding, grazing by microzooplankton, zooplankton predation, and primary productivity) and hot topics (spatial-temporal distribution, morphology, molecular identification, gene expression, and review), we determined that basic studies on diatoms have decreased and that studies tend to be more comprehensive. This study notes that future directions in diatom research will be closely associated with the application of diatoms in environmental management and climate change to cope with environmental challenges, and more comprehensive issues related to diatoms should be considered. [ABSTRACT FROM AUTHOR]