This paper presents the growth and development of mobile technology research across the world publications output on Web of Science during the period 2000 to 2013. A total of 10638 publications were published in the field and an average number of publications published per year was 759.86. The highest number of publications 1495 was published in 2013 and the lowest number of publications is 270 in 2000. The relative growth rates (RGR) has decreased from 2001 (0.78) to 2013 (0.15) in the span of 13 years. The doubling time (DT) has gradually increased from 0.89 in 2001 to 4.62 in 2013. Out of total publications, 4597 were produced by multi authors and 2593 by mega authors. Pattern of co-authorship revealed the improving trend of co-authored publications. The average value of collaboration co-efficient for mobile technology is 0.56. The top 10 countries listed from USA to Spain contributed to 81 % of total output of the literature, USA topped the list with highest share of publications (2738) followed by UK (890), China (823), and South Korea (802) publications, etc. University of California System (USA) is the highly contributed institution with 243 publications followed by University of London (UK) with 149 publications.

Keywords:   Mobile technology  , scientometric analysis  author productivity  relative growth rates

The present paper is furtherance of author's earlier study on mobile technology ‘Mapping of Mobile Technology Publications: A Scientometric Approach’ in DESIDOC Journal of Library and Information Technology 34(4) 2014. The major facts of the study are postulated to mobile technology research in engineering index database. The research shows that mobile technology researcher’s preferred medium of communication is conference articles with the majority of publications were published in English language and a total of 144567 publications were published during 2003 to 2012. The RGR has decreased from 2004 (0.98) to 2012 (0.13) in the span of 10 years. The DT has gradually increased from 0.71 in 2004 to 5.15 in 2012. A total of 1337 authors had contributed entire research output of the period. The research is mainly focused on the growth of literature in the field of mobile technology, identify the prolific authors in the mobile technology, analyse country-wise contributions of the publications and quantify the publications as per the Engineering Index subject fields. Thus the purpose of the present study is to analyse the growth and development of mobile technology research across the world publications output on Web of Science using relative growth rate and doubling time, pattern of co-authorship using co-authorship index and collaboration coefficient, citations per publication and relative citation impact of highly productive countries and most prolific authors along with their origin of the country. ”

The main objective of this study is to analyse the global research performance in the field of mobile technology as reflected in the publication output during 2000 to 2013. The study focuses on the following aspects:

(a) Forms of publications;

(b) Language-wise distribution of publications;

(c) Relative growth rate and doubling time of publications;

(d) Co-authorship pattern of the authors;

(e) Citations per publication and relative citation impact of highly productive countries;

(f) Share of publications of highly productive institutes;

(g) Most prolific authors;

(h) Highly preferred source titles for publication in the field; and

(i) Subject-wise distribution of mobile technology research output.

The Web of Science database was used for retrieving data on mobile technology during 2000-2013, using search term namely ‘mobile technology’ in ‘topic field’. A total of 10638 publications and 138297 citations received to these publications were transferred to spread sheet application and analysed the data as per objectives of the study.

A total of 10638 publications were published in mobile technology during 2000-2013. The highest numbers of publications 8474 (79.66 %) were published as journal articles, followed by conference proceedings with 1418 (13.33 %) publications. Review papers ranks the 3rd position with 417 (3.92 %) and letters in the fourth place with 162 (1.52 %).

Publications on mobile technology are spread over 23 languages. The most predominant language used for communication was English. The English language articles were about 97.80 % and the rest of 2.20 % were scattered in other 22 languages.

The Relative Growth Rate (RGR) is the increase in number of articles or pages per unit of time. The mean RGR over the specific period of interval can be calculated from the following equation.

Relative Growth Rate (RGR)= 1 - 2R = logeW2 – logeW1/T2-T1

where, 1-2R is mean relative growth rate over the specific period of interval; loge W1 is log of initial number of articles; logeW2 is log of final number of articles after a specific period of interval and; T2-T1is the unit difference between the initial time and the final time.

The year can be taken here as the unit of time. Therefore

1-2R (aa-1 year-1) can represent the mean relative growth rate per unit of articles per unit of year over a specific period of interval.

Doubling Time (DT) = 0.693/R

Doubling time for articles DT (a) = 0.693/1-2R (aa-1 year-1)

The analysis of data on the mobile technology output has been done with parameters such as RGR and DT. The data has been analysed and presented in Table 1.

It has been observed from Table 1, RGR decreased from 0.78 in 2001 to 0.16 in 2009. In 2010 to 2012, it remained constant (0.16) which is less than the earlier years. In 2013, of RGR was decreased to 0.15. The value of of publications increased from 0.89 in 2001 to 4.33 in 2009. In 2010 to 2012, it remained constant (4.33) which is more than the earlier years. In 2013, the value of DT was increased to 4.62. The relative growth rate and doubling time for research output is shown in Figure 1.

Table 1 clearly indicates that, the RGR is decreased from 0.78 in 2001 to 0.15 in 2013. Correspondingly, the of DT of the publications gradually increased from 0.89 in 2001 to 4.62 in 2013.

Table 2 presents the distribution of output by single, two, multi and mega authored papers besides the values of the co-authorship index (CAI) and collaboration coefficient (CC) for the entire data was divided into 3 blocks-2000 to 2004, 2005 to 2009 and 2010 to 2013. The average value of CC for mobile technology is 0.56. The calculated value of collaborative coefficient for the study period does not vary much for different years. The value of CC is highest (0.58) for 2002 and 2008 and lowest (0.52) in 2004. However, the value of CC is showing increasing and decreasing trend in the three block year periods.

Table 2 reveals that the result of co authorship index and it is observed that the value of CAI for increasing and decreasing trend in the three block year periods. The values of CAI for two, megapapers. This implies that the collaborative pattern in mobile technology field is mainly characterised by co-authored papers not by single authored papers.

There were 101 countries involved in research in mobile technology field and which published at least one publication as per the database. Table 3 shows that top 20 countries (=130 publications) actively pursuing research in the field. It was observed that top 10 countries listed from USA to Spain 81 % of total output of the research. The USA topped the list with highest share of 25.74 % publications with 47175 citations and citation per publications is 17.23. UK ranked second with 8.37 % share of publications with 11143 citations and its CPP is 12.52, followed by China with 7.74 percent share of publications with 8145 citations and CPP is 9.91.

Among the counties listed in Table 3 only four countries viz. USA, Switzerland, Sweden and Singapore have more than average value of CPP. The remaining 16 countries are less than the average value of CPP. India is the lowest value of CPP. The average value of CPP for the entire research output in the field is 13.

Regarding relative citation impact (RCI) it is observed that USA, Switzerland, Sweden and Singapore have >1 values of RCI and remaining 16 countries values are <1. This indicates that papers published by these four countries were cited more than the average of other countries papers. The value of RCI is highest for Switzerland and lowest for India.

Table 4 shows the top 10 institutions that are contributing more than 40 publications. It is seen form the table that the top ranking institutions viz., University of California System, USA contributed 243 publications and its CPP is 5.14 followed by this, University of London, UK contributed with 149 publications and its CPP is 3.90. Remaining institutions listed in the table contributed less than hundred publications with minimum citations. It is interesting to note that the highest value of CPP 10.52 is belongs to Pennsylvania Commonwealth System for Higher Education (PCSHE), USA contributed 83 publications. Among the institutions listed in Table 4, out of 10 institutions, four institutionsare from USA, and two from China and one each from UK, Taiwan, South Korea, and Finland. A total of 827 individual institutions were involved in producing 10638 articles during the study period.

Table 5 presents rank list of authors who have contributed more than 20 articles are taken into account to avoid a long list. It reveals that Kim, S. University of Rochester, USA is the most productive author contributing 42 articles (0.39 %) followed by Kim, H. Korea University, South Korea with 36 articles (0.34 %) and Kim, J. Kyung Hee University, South Korea with 36 articles (0.3 4 %).

Table 6 shows top 10 source titles along with their country, impact factor and h index for contributing mobile technology articles in Web of Science. The publications on mobile technology were spread over 341 journals. It is found that Lecture Notes in Computer Science, Germany top the list with the highest number of publications of 591 (5.55 %) and the impact factor is 0.51, h index is 118. Followed by this, IEEE Communications Magazine, USA with a share of 216 (2.03 %) with their impact factor 4.46 and h index is 144 and Wireless Personal Communications, Netherlands occupy the third position with 127 (1.19 %) publications with impact factor 0.43 and h index is 29. Highest impact factor of the source titles are IEEE Communications Magazine, USA (4.46) followed by Journal of Chromatography A, Netherlands (4.258).

Table 7 shows high productivity subjects which are contributing more than 300 articles. It is observed that subject Engineering has highest number of articles, i.e, 3600 with 38699 citations and CPP is 10.75. Followed by Computer Science contributing 3430 articles with 29674 citations and citation per publication is 8.65. Telecommunications occupy the third position with 2509 articles along with 17279 citations and CPP is 6.88. The fourth highest articles belonged to the subject Business Economics 552 articles with 7916 citations and CPP is 14.34.

The present paper shows the mobile technology publication output on Web of Science during the period 2000 to 2013. A total of 10638 publications were published in the field and an average number of publications published per year was 759.86. But in the earlier study mobile technology publication output as reflected in Engineering Index database during 2003 to 2012 and a total of 144567 publications were published in the field and an average number of publications published per year was 14456.7. The highest numbers of publications 8474 (79.66 %) were published in journal articles, followed by conference proceedings with 1418 (13.33 %) publications. But in the earlier study conference articles with 94205 (65.16 %) followed by journal articles with 48363 publications (33.45 %).

As per language distribution, in the present paper it is spread over 23 languages. But in the earlier study, there are 20 languages. More than 95 % of publications are published in English in both studies.

The RGR is decreased from 0.78 in 2001 to 0.15 in 2013 and DT of the publications gradually increased from 0.89 in 2001 to 4.62 in 2013 in the span of 14 years of this study. But in earlier study, the RGR has decreased from 2003 (0.98) to 2012 (0.13) and the DT increased from 0.71 in 2003 to 5.15 in 2012 in the span of 10 years.

In this study, there were 101 countries involved in research in mobile technology field. The USA topped the list with 2738 publications followed by UK with 890 publications. China ranked 3rd position with 823 publications and India stood 16th rank with 202 publications. But in the earlier study, there are 75 countries involved in carrying out research in the field. China ranked 1st 33010 publications followed by USA with 19166 publications. Japan ranked third position with 11730 publications and India stood 7th rank with 6150 publications.

A total of 1337 authors had contributed entire research output of the earlier study. Wang, Wei is the most productive author contributing 223 articles followed by Barolli, Leonard with 160 articles and Wong, Kin Lu with 154 articles respectively. The analysis on author affiliation reveals that in the earlier paper the Institute of Electrical and Electronics Engineering of USA tops the list with 1248 articles followed by National Mobile Communications Research Laboratory, Southeast University, China with 508 publications. But in the current paper the University of California System, USA tops the list with 243 articles followed by University of London, UK with 149 publications.

The high productive subjects areas identified this paper is Engineering with 3600 publications and CPP is 10.75, followed by Computer Science contributing 3430 publications and CPP is 8.65. The highest number of articles contributed on Wireless Telecommunication Systems with 20585 publications followed by Mobile Telecommunication Systems with 18423 publications in the earlier study.

The present paper is mobile technology publication output on Web of Science during the period 2000 to 2013. The highest numbers of publications 8474 (79.66 %) were published in journal articles, followed by conference proceedings with 1418 (13.33 %) publications. Kim, S. University of Rochester, USA is the most productive author contributing 42 articles (0.39 %) followed by Kim, H. Korea University, South Korea with 36 articles (0.34 %) and Kim, J. Kyung Hee University, South Korea with 36 articles (0.34 %) respectively. Lecture Notes in Computer Science, Germany gets top rank in terms of number of publications and IEEE Communications Magazine, USA gets top rank in terms of impact factor. As usual, journal articles were the preferred medium of authors in the field to communicate their research works and English was the most predominant language in which 98 % of the articles was published. The pattern of authorship indicates that the discipline of mobile technology is dominated by multi authored publications. The findings of the present Scientometric study will be beneficial for the researchers, who are engaged in research on various disciplines of mobile technology in future.

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Mr R. Santhakumar is presently working as Librarian in SKR Engineering College, Chennai. He obtained MSc (Physics) from Alagappa University, Karaikudi, MLIS, MPhil and PGDCA from Madurai Kamaraj University. He has published 12 journal articles in national and international journals and presented 16 articles both in national and international conferences.