Liming Liang

H-index sequence and h-index matrix : Constructions and applications

SummaryThe calculation of Hirschs h-index is a detail-ignoring way, therefore, single h-index could not reflect the difference of time spans for scientists to accumulate their papers and citations. In this study the h-index sequence and the h-index matrix are constructed, which complement the absent details of single h-index, reveal different increasing manner and the increasing mechanism of the h-index, and make the scientists at different scientific age comparable.

The role of Chinese universities in enterprise---university research collaboration

In this paper the role of Chinese universities in enterprise–university research collaboration is investigated. This study focuses on a special aspect of the collaboration—co-authored articles. The two cases are analyzed: (1) research collaboration between Baosteel Group Corporation and Chinese universities; (2) research collaboration between China Petroleum & Chemical Corporation and Chinese universities. The co-authorship data over the period 1998–2007 were searched from CNKI database, the largest Chinese publication and citation database. The main findings are as follows: the number of articles co-authored by enterprise and university scientists has been increasing rapidly; the share of co-authored articles has been growing; the authors from universities are more possible to be the first authors; as a whole, enterprise–university co-authored articles tend to receive more citations and get downloaded more frequently; a mathematical orientation emerges in the enterprise–university articles. To reveal and describe such a trend the methods of keywords analysis and co-occurrence analysis are applied. The Chinese government’s policy instruments and substantial supports for pushing and improving enterprise–university research collaboration are introduced and analyzed.

Age Structures of Scientific Collaboration in Chinese Computer Science

This paper is a scientometric study of the age structure of scientific collaboration in Chinese computer science. Analysis reveals some special age structures in scientific collaboration in Chinese computer science. Most collaborations are composed of scientists younger than thirty-six (Younger) or older than fifty (Elder). For two-dimensional collaboration formed by first and second authors, Younger-Elder and Younger-Younger are the predominant age structures. For three-dimensional collaboration formed by first, second and third authors, Younger-Younger-Elder and Younger-Younger-Younger are the most important age structures. Collaboration between two authors older than 38 amounts to only 6.4 percent of all two-person collaborations. Collaboration between two middle-aged scientists is seldom seen.Why do such types of age structure in Chinese computer science exist? We suggest a tentative explanation based on analyses of the age composition of all authors, the age distributions of the authors in different ranks, and the name-ordering of authors in articles written by professors and their students.

Non-English journals and papers in physics and chemistry: bias in citations?

This study investigates, at the journal as well as the article level, if there is a difference in citations between English-language and non-English publications. The Web of Knowledge is used as data source. The investigation focuses on the fields of physics and chemistry. Using a precise definition of a “non-English journal”, we filter out nine physics and thirty-four chemistry non-English journals, scattered over six physics and seven chemistry subfields. Average received citations per paper (CpP) of the non-English journal(s) are compared with the CpP of pure English journals, and this in the same subfield. We clearly observe that non-English journals are inferior—in number of citations received—to pure English journals and this in all physics and chemistry subfields studied. Further, twelve physics journals and ten chemistry journals were chosen as sample journals to compare the CpP of non-English papers with that of English language papers in the same journal. The result of this comparison is that for the majority of these journals and for most of the publication years the CpP of non-English papers is lower than that of the English language papers. Finally, analyzing linguistic characteristics of the citing literature confirms the own-language preference in non-English physics and chemistry journals.

R‐sequences: Relative indicators for the rhythm of science

Like most activities in the world, scientific evolution has its own rhythm. How can this evolutionary rhythm be described and made visible? Do different fields have different rhythms, and how can they be measured? In order to answer these questions a relative indicator, called R-sequence, was designed. This indicator is time dependent, derived from publication and citation data, but independent of the absolute number of publications, as well as the absolute number of citations, and can therefore be used in a comparison of different scientific fields, nations, institutes, or journals. Two calculation methods of the R-sequence - the triangle method and the parallelogram method - are introduced. As a case study JASIS(T)s R-sequence has been obtained.

Yield sequences as journal attractivity indicators: “payback times” for Science and Nature

Purpose – The yield period of a journal is defined as the time needed to accumulate the same number of citations as the number of references included during the period of study. Yield sequences are proposed as journal attractivity indicators describing dynamic characteristics of a journal. This paper aims to investigate their use.Design/methodology/approach – As a case study the yield sequences of the journals Nature and Science from 1955 onward are determined. Similarities and dissimilarities between these sequences are discussed and factors affecting yield periods are determined.Findings – The study finds that yield sequences make dynamic aspects of a journal visible, as reflected through citations. Exceptional circumstances (here the publication of Laemmlis paper in 1970 in the journal Nature) become clearly visible. The average number of references per article, the citation distribution and the size of the database used to collect citations are factors influencing yield sequences.Originality/value – ...

Structural similarities between science growth dynamics in China and in western countries

SummaryTo compare science growth of different countries is both, of theoretical and of pragmatic interest. Using methods for the analysis of complex growth processes introduced by H. E. Stanley and others, we exhibit quantitative features of Chinese science growth from 1986 to 1999 and compare them with corresponding features of western countries. Patterns of growth dynamics of Chinese universities publication output do not differ significantly from those found in the case of western countries. The same is valid for Chinese journals when compared to international journals. In nearly all cases the size distribution of output over universities or journals is near to a lognormal one, the growth rate distribution is Laplace-like, and the standard deviations of the corresponding conditional distributions with regard to size decay according to a power law. This means that regarding some structural-dynamical properties Chinas recent science system cannot be distinguished from a western one - despite different prehistory and different political and economic environment.

A rhythm indicator for science and the rhythm of Science

SummaryThe rhythm of science may be compared to the rhythm of music. The R-indicator studied in this article is a complex indicator, trying to reflect part of this rhythm. The R-indicator interweaves publication and citation data over a long period. In this way R-sequences can be used to describe the evolutionary rhythm of science considered in a novel way. As an example the R-sequence of the journal Science from 1945 on is calculated.

Uncited papers, uncited authors and uncited topics: A case study in library and information science

In this article we study three types of uncitedness in Library and Information Science journals: uncitedness for articles, authors and topics. One important aspect in this study is giving accurate definitions of the indicators for measuring uncited papers, uncited authors and uncited topics. It is found that for the period 1991–2010 ratios of uncited papers fluctuate within the interval [0,0.1]. This ratio is relatively stable and not very high. Comparison of average number of pages, average number of references, average number of authors per paper and percentage of single-authored papers between cited and uncited papers shows that no matter the journal, the first three indicators’ values for uncited papers are lower, while the values of the fourth indicator are higher, than the corresponding values for cited papers. The fact that almost all uncited authors in a journal published only one paper in this journal illustrates that a journals uncited authors are the least productive authors in this journal. Yet, productive and highly cited authors also publish uncited papers. As to why some topics fall into the group of uncited topics, the hypothesis is that the combination of unfamiliar keywords forms an unfamiliar topic, a topic authors have elected not to study further. Another assumption is that some uncited topics fall outside the field of Library and Information Science. Retrieval results in the Web of Science for a set of uncited keywords and keyword combinations support this assumption.

Transformations of basic publication–citation matrices

Basic publication–citation matrices are used to calculate informetric indicators such as journal impact factors or R-sequences. Transforming these publication–citation matrices clarifies the construction of other indicators. In this article, some transformations are highlighted together with some of their invariants. Such invariants offer a rigorous mathematically founded way of comparing informetric matrices before and after a transformation.