Crack StatPlanet Plus 3 0
Sandrine Willert
The explosive growing number of data from mobile devices, social media, Internet of Things and other applications has highlighted the emergence of big data. This paper aims to determine the worldwide research trends on the field of big data and its most relevant research areas. A bibliometric approach was performed to analyse a total of 6572 papers including 28 highly cited papers and only papers that were published in the Web of ScienceTM Core Collection database from 1980 to 19 March 2015 were selected. The results were refined by all relevant Web of Science categories to computer science, and then the bibliometric information for all the papers was obtained. Microsoft Excel version 2013 was used for analyzing the general concentration, dispersion and movement of the pool of data from the papers. The t test and ANOVA were used to prove the hypothesis statistically and characterize the relationship among the variables. A comprehensive analysis of the publication trends is provided by document type and language, year of publication, contribution of countries, analysis of journals, analysis of research areas, analysis of web of science categories, analysis of authors, analysis of author keyword and keyword plus. In addition, the novelty of this study is that it provides a formula from multi-regression analysis for citation analysis based on the number of authors, number of pages and number of references.
Highly cited papers have a greater chance of visibility, thus attracting greater attention among researchers [25]. Evaluating the top cited publications content is very useful for obtaining information about the trends of specific fields in the perspective of research progress [26]. It can reveal to researchers how they can find the best field or best journal to succeed in their publication. Although, the citation is not a scientific tool to assess the publication, it is a valuable metric that recognizes research parameters [27]. The citation index, as a type of bibliometric method, shows the number of times an article has been used by other papers [28]. Hence, citation analysis helps researchers to obtain a preliminary idea about the articles and research that has an impact in a particular field of interest and it deals with the examination of the documents cited by scholarly works [29, 30]. In addition, there are various bibliometric studies has been evaluated based on different metrics and applications such as forecasting emerging technologies by using bibliometric and patent analysis [31], multiple regression analysis for Japanese patent case [32], medical innovation using medical subject headings [33], based on region or countries [34,35,36], number of authors [37, 38] and a bibliometric analysis based on number publications and cited references [39].
Besides the highly cited papers, which were reported by ESI, the citations per year were calculated as a division of the total citations by life year of the article. The citations per year are more accurate and more scientific than the total citations to identify the top cited papers [44, 45]. Citation statistics produced for a period of less than 3 years may not be sufficiently stable [46, 47]. Therefore, we only select the papers published up to 19 March 2015 for citation analysis. The rest of the analyses were based on the whole dataset. The emphasis of the research was to describe trends in physical activity and ageing research from the following five aspects:
The research will provide a guideline based on the publication trend and impact for future research. After classifying and extracting the data, the process of analyzing was started and the observations include statistical analysis, statistical descriptions, statistical tests, ANOVA, and regression analysis of some of the factors chosen. The ANOVA table was constructed using Microsoft Excel version 2013 [48], which can be used to show the statistical relationship between two variables. In addition, a free version of StatPlanet Plus [49] software was used in this study for creating the interactive world map to visualize the distribution of all papers among different countries.
The last part of the analysis focused on the multiple regressions of three factors concerning the number of citations. The three independent variables in this regression were number of authors, number of pages and number of references, form each of the 6572 papers, and the dependent variable was the number of citations of each paper (out of 6572). By using Microsoft Excel 2013, the t-test was constructed to analyze how strongly these three factors contribute to the number of citations. At the end of this analysis, this study produced a multiple regression equation, which could be used to forecast the number of citations giving the number of pages, authors and references.
As discussed above, the total of 6572 papers was refined by all WoS categories relevant to computer science (Additional file 1). Hence, various bibliometric tools to evaluate the different metrics were selected to determine the research trends based on the two groups that extracted from WoS: All Papers (6572) and Highly Cited Papers (28) groups. In addition, we have not discounted double counting in papers co-authored from multi countries; therefore, the results shown below or in other tables might be counted more than the real data as 28 papers for highly cited papers and 6572 papers for all papers.
Table 5 illustrates the main distribution of document types in both groups (all and highly cited papers). In the all papers group, proceeding papers (62.73%) and articles (38.61%) are the main contributors, whereas in the highly cited papers, articles (89.28%) is only the highest contributor. We found that English was the dominant language with 6549 records (99.65%). Other less significant outputs for all papers were editorial material, review, meeting abstract, news item, book review, letter, correction, software review, book chapter, item about an individual, note, and reprint; for highly cited papers it was the same with lower significant percentages for review and proceeding paper (Table 5).
Even though, proceeding paper and article were the most used document types, we also considered all the document types, as shown in Table 5. We believe that each document type has its own intrinsic value and would provide insight on the research trend.
The recent research concentration is reflected in its publication output [76, 77]. Figure 3 shows the number of published items spanning 36 years from 1980 to 19 March 2015. In general, the number of publications increased over the period studies. A huge positive jump from 1 year to another can be seen from 2012 to 2013, with a difference of 395 publications. If the last three recent years is excluded from the observation, the highest drop can be observed between 2009 and 2010, the published items dropped by 146 items. In the first 16 years in Fig. 3, the count movement of publications steadily increased but with a very small increment. It can be clearly seen from the trend of the graph that there is a sudden jump in the initial period after a long steady movement, which was between 1993 and 1994. On average, the number of papers published every year was 182.56 with a standard deviation of 280.03. It can be concluded that, the shape of the graph is skewed to the right, which consistently agrees with the huge value for standard deviation generated from Excel.
In general, the number of publications is increasing over the years considered. But, in 2009, 2012 and 2013 we observed sudden spikes in the number of publications. Further analysis we found, there were more research activities reporting on proceeding papers in those years compared to their previous year. For instance, there were 556 proceeding papers in 2012 and 260 proceeding papers in 2011.
The geographical world map shows that there has been a gradual increase in the number of publications in North and South America, and that it has a higher impact in the world. We found that among the 196 countries in the world, 96 countries such as South Africa and a few countries in the Middle East have no publications. The present results show that big data is a growing area of research in most countries.
The comparison of the top ten countries with the highest publications for all and highly cited papers are shown in (Additional file 1). The top three countries for both groups were the USA, China and Germany with the combined total numbering over 3000 publications produced. Over 36 years, the average for the USA was 51.44 meaning that there were more than 51 publications. In other words, this was over 22 publications (22.02) higher than China for each year. Our analysis shows that there was huge positive correlation between the number of publications by country in all and highly cited papers. The coefficient of determination between these two groups was 0.90. The ANOVA table, which was extracted from Excel, is shown in (Additional file 1). The F-value retrieved from the ANOVA table was 10.54; this was higher than its F-crit. (3.88), which was set at the 5% level of significance. Based on the result obtained from the ANOVA test, the null hypothesis was rejected and there was strong evidence to show that the number of publications for each country for all papers had an impact on the number of publications of the country in highly cited papers.
The comparison the top ten WoS categories based on the total number of publications in all and highly cited papers are shown in (Additional file 1). In total, there were 96 WoS categories for which the Computer Science Theory Methods (2624) had the highest number of publications in the all papers group, while, in the highly cited group, the first category of WoS was Computer Science Artificial Intelligence (10). It is evident that computer science categories and related subjects are the leading fields in big data research.
Table 6 depicts the top 10 Journals between all and highly cited papers by their impact factor for 2012 and 2013. Commonly, researchers believe that the high journal impact factor shows the high value of the journals. But, we found that there were some journals with a lower impact factor that contained the highly cited papers.
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