# On the structure of graphs with path-width at most two

Authors: János Barát, Péter Hajnal, Yixun Lin and Aifeng Yang

Kinnersley and Langston used a computer search to characterize the class of graphs with path-width at most two. The excluded minor list consists of 110 graphs. This set is fairly large, and the list gives little insight to structural properties of the targeted graph class. We take a different route here. We concentrate on the building blocks of the graphs with path-width at most two and how they are glued together. In this way, we get a short and compact characterization of 2-connected and 2-edge-connected graphs with path-width at most two.

Restricted access

# Pointwise convergence of Marcinkiewicz-Fejér means of two-dimensional Walsh-Fourier series

Authors: Ushangi Goginava and Ferenc Weisz

In this paper we characterize the set of convergence of the Marcinkiewicz-Fejér means of two-dimensional Walsh-Fourier series.

Restricted access

# Strong approximation of two-dimensional Walsh-Fourier series

Authors: Ushangi Goginava and Larry Gogoladze

In this paper we study the exponential uniform strong approximation of two-dimensional Walsh-Fourier series. In particular, it is proved that the two-dimensional Walsh-Fourier series of the continuous function f is uniformly strong summable to the function f exponentially in the power 1/2. Moreover, it is proved that this result is best possible.

Restricted access

# w-overrings of w-Noetherian rings

Authors: Huayu Yin and Youhua Chen

In this paper, we concern the w-analogue of Matijevic’s result. We show that if R is a w-Noetherian ring and T a w-overring of R such that TR wg. Then T has ACC on regular w-ideals.

Restricted access

# Blockmodeling of co-authorship networks in library and information science in Argentina: a case study

Authors: Zaida Chinchilla-Rodríguez, Anuska Ferligoj, Sandra Miguel, Luka Kronegger and Félix de Moya-Anegón

## Abstract

The paper introduces the use of blockmodeling in the micro-level study of the internal structure of co-authorship networks over time. Variations in scientific productivity and researcher or research group visibility were determined by observing authors’ role in the core-periphery structure and crossing this information with bibliometric data. Three techniques were applied to represent the structure of collaborative science: (1) the blockmodeling; (2) the Kamada-Kawai algorithm based on the similarities in co-authorships present in the documents analysed; (3) bibliometrics to determine output volume, impact and degree of collaboration from the bibliographic data drawn from publications. The goal was to determine the extent to which the use of these two complementary approaches, in conjunction with bibliometric data, provides greater insight into the structure and characteristics of a given field of scientific endeavour. The paper describes certain features of Pajek software and how it can be used to study research group composition, structure and dynamics. The approach combines bibliometric and social network analysis to explore scientific collaboration networks and monitor individual and group careers from new perspectives. Its application on a small-scale case study is intended as an example and can be used in other disciplines. It may be very useful for the appraisal of scientific developments.

Restricted access

# Erratum to: Journal report card

Author: Judit Bar-Ilan
Restricted access

# On moduli of p-continuity

Authors: V. I. Kolyada and M. Lind

## Abstract

Moduli of p-continuity provide a measure of fractional smoothness of functions via p-variation. We prove a sharp estimate of the modulus of p-continuity in terms of the modulus of q-continuity (1<p<q<∞).

Restricted access

# The ultrafilter number for singular cardinals

Authors: Shimon Garti and Saharon Shelah

## Abstract

We prove the consistency of a singular cardinal λ with small value of the ultrafilter number , and arbitrarily large value of 2λ.

Restricted access

# Grim tales about the impact factor and the h-index in the Web of Science and the Journal Citation Reports databases: reflections on Vanclay's criticism

Author: Peter Jacso

## Abstract

This paper reflects on the most current and some of the recent contributions of JK Vanclay, focusing on his methods, findings, and criticism about the journal citations reports and the web of science databases, the journal impact factor and the h-index. It is argued and demonstrated that some of the recent papers of the author about scientometric issues, measures and sources show so much demagoguery, ignorance and arrogance, have so much prejudice and bias, so profound errors in using the databases, calculating metrics, and interpreting search results that the papers are very unlikely to be meant as a genuine contribution from an academic who is a graduate of—among others—Oxford University, professor and dean in a respected university, a well-published and well-cited author and a recipient of the Queen's Award (all the above in forest science). The papers are much more likely to serve as props for a staged, mock-up scenario based on slipshod research in an experiment, to illustrate the deficiencies in the processes and in the assessment of scholarly publishing productivity and impact in order to present the idealized solution of Vanclay: using the h-index, portrayed as the Prince, mounted on the shoulder of the White Horse, Google Scholar.

Restricted access

# Participation of women in software engineering publications

Authors: Belén Vela, Paloma Cáceres and José María Cavero

## Abstract

To the best of our knowledge, no works analyzing the participation of women as authors and editors in software engineering research publications currently exist. We have therefore followed a well-defined procedure in order to conduct an empirical study of female participation in 12 leading software engineering journals. We have analyzed the gender of the authors, editorial board members, associate editors and editors-in-chief over a two-year period in order to analyze, on the one hand, the rate of participation of women as authors and as editors in software engineering publications, and on the other, whether women are underrepresented. We have also analyzed the female distribution of authors and editors according to the geographical location of their institutions. This was done by first selecting the journals to be used as the population for data collection which then allowed us to identify female authors of papers and female editors, including the country in which their institutions are located. This eventually led to an analysis of female participation in order to understand representation rates. We analyzed 3,546 authors of 1,266 papers in 61 different countries, and 363 members of editorial boards in 30 different countries. The results of this analysis provide quantitative data concerning the participation of women as authors and editors in major software engineering journals including their distribution per country, in which important differences have been found. The results obtained were first used to compare the participation of women as authors and editors and were then used to carry out a series of simulations in order to be able to statistically confirm whether women are underrepresented. The study shows, amongst other things, that women are not underrepresented as editorial boards members and as editors-in-chief of the journals studied, although their representation as editors-in-chief is low.

Restricted access

# The d-index: Discovering dependences among scientific collaborators from their bibliographic data records

Authors: Luigi Di Caro, Mario Cataldi and Claudio Schifanella

## Abstract

The evaluation of the work of a researcher and its impact on the research community has been deeply studied in literature through the definition of several measures, first among all the h-index and its variations. Although these measures represent valuable tools for analyzing researchers’ outputs, they usually assume the co-authorship to be a proportional collaboration between the parts, missing out their relationships and the relative scientific influences. In this work, we propose the d-index, a novel measure that estimates the dependence degree between authors on their research environment along their entire scientific publication history. We also present a web application that implements these ideas and provides a number of visualization tools for analyzing and comparing scientific dependences among all the scientists in the DBLP bibliographic database. Finally, relying on this web environment, we present case and user studies that highlight both the validity and the reliability of the proposed evaluation measure.

Restricted access

# A general framework for describing diversity within systems and similarity between systems with applications in informetrics

Authors: Qiuju Zhou, Ronald Rousseau, Liying Yang, Ting Yue and Guoliang Yang

## Abstract

Building on the ideas of Stirling (J R Soc Interface, 4(15), 707–719, ) and Rafols and Meyer (Scientometrics, 82(2), 263–287, ), we borrow models of genetic distance based on gene diversity and propose a general conceptual framework to investigate the diversity within and among systems and the similarity between systems. This framework can be used to reveal the relationship of systems weighted by the similarity of the corresponding categories. Application of the framework to scientometrics is explored to evaluate the balance of national disciplinary structures, and the homogeneity of disciplinary structures between countries.

Restricted access

# An Inno-Qual performance system for higher education

Authors: Jui-Kuei Chen and I-Shuo Chen

## Abstract

Due to the overall decrease in quality of Taiwanese universities in recent years and the resulting drastic loss of competitive advantage against foreign countries, improving the Taiwanese university system has become an urgent issue requiring immediate attention. Evidence suggests focusing on total quality management (TQM) and that innovation is the key way to effectively upgrade the operation performance and is thus highly advised. Although there are a number of measurement models for TQM and innovation, early models evaluate the performance of each element separately, making evaluation inefficient and inappropriate for practice. There is a new measurement system, the network hierarchical feedback system (NHFS), which integrates the concept and characteristics of both elements; however, the major concern is that the NHFS does not take external organization-oriented improvement into account, such as service quality in higher education, especially in innovation orientation. Additionally, due to the above dilemmas faced by Taiwanese universities, attracting more students has now been a major priority. Thus, we argue that in order to successfully attract potential students, improving TQM and innovation cannot just focus on internal organization-oriented improvement, and we further extend the effectiveness and suitability of the NHFS to a novel and more utilizable performance measurement system, the solid Inno-Qual performance system (IQPS). A hybrid model based on a decision-making trial and evaluation laboratory, a fuzzy analytic network process (FANP), an importance–performance analysis along with in-depth interviews; a fuzzy analytic hierarchical process, and a technique for order preference according to similarity to an ideal solution were adopted to complete the construction. The IQPS is the first measurement system with the most effective characteristics of TQM and innovation embedded for both new and traditional universities of different types. It is intended to enhance and evaluate performance on both external and internal organization-oriented levels, generating synergy and performance improvement.

Restricted access

# Prescribed practices of authorship: review of codes of ethics from professional bodies and journal guidelines across disciplines

Authors: Lana Bošnjak and Ana Marušić

## Abstract

Guidelines on authorship requirements are common in biomedical journals but it is not known how authorship is defined by journals and scholarly professional organizations across research disciplines. Prevalence of authorship statements, their specificity and tone, and contributions required for authorship were assessed in 185 journals from Science Citation Index (SCI) and Social Science Citation Index (SSCI), 260 journals from Arts & Humanities Citation Index (A&HCI) and 651 codes of ethics from professional organizations from the online database of the Center for the Study of Ethics in the Profession, USA. In SCI, 53 % of the top-ranked journals had an authorship statement, compared with 32 % in SSCI. In a random sample of A&HCI-indexed journals, only 6 % of the journals addressed authorship. Only 71 (11 %) codes of ethics carried a statement on authorship. Almost all journals had defined authorship criteria compared with 33 % of the ethics codes ( = 75.975; P < 0.001). The tone of the statements in the journals was aspirational, whereas ethics codes used a normative language for defining authorship ( = 51.709, P < 0.001). Journals mostly required both research and writing contributions for authorship, while two-thirds of the ethics codes defined only research as a mandatory contribution. In conclusion, the lack of and variety of authorship definitions in journals and professional organizations across scientific disciplines may be confusing for the researchers and lead to poor authorship practices. All stakeholders in research need to collaborate on building the environment where ethical behaviour in authorship is a norm.

Restricted access

# S&T publications output of Nepal: a quantitative analysis, 2001–10

Authors: B. M. Gupta and Adarsh Bala

## Abstract

This study analyses the research output of Nepal in S&T during 2001–10 on several parameters including its growth and country publications share in the world's research output, country publications share in various subjects in the national and global context, pattern of research communication in core domestic and international journals, geographical distribution of publications, share of international collaborative publications at the national level as well as across subjects and characteristics of high productivity institutions, authors and cited papers. The Scopus Citation Database has been used to retrieve the publication data for 10 years.

Restricted access

# Erdős-Zaks all divisor sets

Authors: Scott Chapman and William Smith

## Abstract

Let ℤn be the finite cyclic group of order n and S ⊆ ℤn. We examine the factorization properties of the Block Monoid B(ℤn, S) when S is constructed using a method inspired by a 1990 paper of Erdős and Zaks. For such a set S, we develop an algorithm in Section 2 to produce and order a set {M i}i=1 n−1 which contains all the non-primary irreducible Blocks (or atoms) of B(ℤn, S). This construction yields a weakly half-factorial Block Monoid (see [9]). After developing some basic properties of the set {M i}i=1 n−1, we examine in Section 3 the connection between these irreducible blocks and the Erdős-Zaks notion of “splittable sets.” In particular, the Erdős-Zaks notion of “irreducible” does not match the classic notion of “irreducible” for the commutative cancellative monoids B(ℤn, S). We close in Sections 4 and 5 with a detailed discussion of the special properties of the blocks M1 with an emphasis on the case where the exponents of M 1 take on extreme values. The work of Section 5 allows us to offer alternate arguments for two of the main results of the original paper by Erdős and Zaks.

Restricted access

# Multiplicative character sums and products of sparse integers in residue classes

Authors: Alina Ostafe and Igor Shparlinski

## Abstract

We estimate multiplicative character sums over the integers with a fixed sum of binary digits and apply these results to study the distribution of products of such integers in residues modulo a prime p. Such products have recently appeared in some cryptographic algorithms, thus our results give some quantitative assurances of their pseudorandomness which is crucial for the security of these algorithms.

Restricted access

# Multiplicative character sums of Fermat quotients and pseudorandom sequences

Authors: Domingo Gomez and Arne Winterhof

## Abstract

We prove a bound on sums of products of multiplicative characters of shifted Fermat quotients modulo p. From this bound we derive results on the pseudorandomness of sequences of modular discrete logarithms of Fermat quotients modulo p: bounds on the well-distribution measure, the correlation measure of order , and the linear complexity.

Restricted access

# On the best approximation of periodic functions by trigonometric polynomials and the exact values of widths of function classes in L 2

Authors: М. Шлбоэов and С. Влклрчук

## Реэюме

Получены точные неравенства типа Джексона-Стечкина для ос-редненных с весом модулей непрерывности m-го (m ∈ ℕ) порядка. Для классов функций, определенных при помоши мажорант и укаэанных осредненных величин, вычислены точные эначения раэличных n-поперечников при выполнении определенных ограничений на мажоранты.

Restricted access

# On the Davenport constant and on the structure of extremal zero-sum free sequences

Authors: Alfred Geroldinger, Manfred Liebmann and Andreas Philipp

## Abstract

Let

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$G = C_{n_1 } \oplus \cdots \oplus C_{n_r }$$ \end{document}
with 1 < n 1 | … | n r be a finite abelian group, d*(G) = n 1 +…+n rr, and let d(G) denote the maximal length of a zerosum free sequence over G. Then d(G) ≥ d*(G), and the standing conjecture is that equality holds for G = C n r. We show that equality does not hold for C 2C 2n r, where n ≥ 3 is odd and r ≥ 4. This gives new information on the structure of extremal zero-sum free sequences over C 2n r.

Restricted access

# Optimal reparametrization and large sample likelihood inference for the location-scale skew-normal model

Authors: Rolando Cavazos-Cadena and Graciela González-Farías

## Abstract

Motivated by results in Rotnitzky et al. (2000), a family of parametrizations of the location-scale skew-normal model is introduced, and it is shown that, under each member of this class, the hypothesis H 0: λ = 0 is invariant, where λ is the asymmetry parameter. Using the trace of the inverse variance matrix associated to a generalized gradient as a selection index, a subclass of optimal parametrizations is identified, and it is proved that a slight variant of Azzalini’s centred parametrization is optimal. Next, via an arbitrary optimal parametrization, a simple derivation of the limit behavior of maximum likelihood estimators is given under H 0, and the asymptotic distribution of the corresponding likelihood ratio statistic for this composite hypothesis is determined.

Restricted access

# Sumsets of sparse sets

Authors: Artūras Dubickas and Paulius Šarka

## Abstract

Let σ be a constant in the interval (0, 1), and let A be an infinite set of positive integers which contains at least c 1 x σ and at most c 2 x σ elements in the interval [1, x] for some constants c 2 > c 1 > 0 independent of x and each xx 0. We prove that then the sumset A + A has more elements than A (counted up to x) by a factor

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${{c\left( \sigma \right)\sqrt {\log x} } \mathord{\left/ {\vphantom {{c\left( \sigma \right)\sqrt {\log x} } {\log }}} \right. \kern-\nulldelimiterspace} {\log }}$$ \end{document}
log x for x large enough. An example showing that this function cannot be greater than ɛ log x is also given. Another example shows that there is a set of positive integers A which contains at least x σ and at most x σ+ɛ elements in [1, x] such that A + A is greater than A only by a constant factor. The proof of the main result is based on an effective version of Freiman’s theorem due to Mei-Chu Chang.

Restricted access

# Абсолютная сходимость простых и двойных рядов Фурье по мультипликативным системам

Authors: B. Golubov and S. Volosivets

## Abstract

Several sufficient conditions for generalized absolute convergence of single and double Vilenkin-Fourier series of bounded type are obtained. These conditions give multiplicative analogues of results due to L. Gogoladze and R. Meskhia, F. Móricz and A. Veres, M. Izumi and S. Izumi. Some of them are sharp in a certain sense.

Restricted access

# О сходимости синус-рядов в L 1

Author: László Leindler

## Abstract

Our aim is to find the source why the logarithm sequences play the crucial role in the L 1-convergence of sine series. We define three new classes of sequences; one of them has the character of the logarithm sequences, the other two are the extensions of the class defined by Zhou and named Logarithm Rest Bounded Variation Sequences. In terms of these classes, extended analogues of Zhou’s theorems are proved.

Restricted access

# Об условии средней ограниченной вариации и его применении в двойных тригонометрических рядах

Authors: Dansheng Yu, Ping Zhou and Songping Zhou

## Abstract

We introduce a new kind of double sequences named MVBVDS and some new classes of weight functions to study the weighted integrability of the double trigonometric series. Several results of Chen, Marzuq, Móricz, Ram and Singh Bhatia (see [2]–[10]) are generalized and some new results are established.

Restricted access

# Улучшенное обобщение одного неравенства типа Гёльдера

Authors: Josip Pečarić and Ksenija Smoljak

## Abstract

In this paper an extension of a Hölder-type inequality given in [C. E. M. Pearce and J. Pečarić, On an extension of Hölder’s inequality, Bull. Austral. Math. Soc., 51(1995), 453–458] is improved using log-convexity. Furthermore, new Cauchy-type means are defined and their monotonicity property is proven.

Restricted access

# Comparison of trends in the quantity and variety of Science Citation Index (SCI) literature on human pathogens between China and the United States

Authors: Deqiao Tian, Yunzhou Yu, Yumin Wang and Tao Zheng

## Abstract

The proportion of pathogenic microorganisms in the microbial world is relatively small, while their threat to human health, economic development and social stability is severe. The quantity and variation of Science Citation Index (SCI) literature related to pathogenic microorganisms may reflect the level of relevant research and the degree of attention. Here we compared trends in the quantity and variety of SCI literature relating to certain important pathogenic microorganisms published by scientists from United States and China from 1996 to 2010 by searching the Science Citation Index database. The pathogenic microorganisms in this study comprise two categories of pathogens: Bacillus anthracis, Yersinia pestis, Francisella tularensis, Ebola virus, Burkholderia pseudomallei, which belong to biodefense-associated pathogens (BDAPs) and the human immunodeficiency virus (HIV), SARS coronavirus, hepatitis B virus (HBV), Mycobacterium tuberculosis, influenza virus, which belong to the commonly encountered health-threatening pathogens. Our results showed that the United States (US) published much more SCI literature on these pathogens than China. Furthermore, literature on BDAPs published by scientists from the US has increased sharply since 2002. However, the numbers of literature relating to CEHTPs from China has demonstrated a gradual increase from 1996 to 2010. Research into pathogenic microorganisms requires three balance to be achieved: investment in BDAP and CEHTP studies; basic and applied research; a faster pace of research into pathogens and fulfilling biosafety and biosecurity requirements.

Restricted access

# Discovery of factors influencing citation impact based on a soft fuzzy rough set model

Authors: Mingyang Wang, Guang Yu, Shuang An and Daren Yu

## Abstract

In this paper, the machine learning tools were used to identify key features influencing citation impact. Both the papers’ external and quality information were considered in constructing papers’ feature space. Based on the feature space, the soft fuzzy rough set was used to generate a series of associated feature subsets. Then, the KNN classifier was used to find the feature subset with the best classification performance. The results show that citation impact could be predicted by objectively assessed factors. Both the papers’ quality and external features, mainly represented as the reputation of the first author, are contributed to future citation impact.

Restricted access

# A new approach for automatizing the analysis of research topics dynamics: application to optoelectronics research

Author: Jean-Charles Lamirel

## Abstract

The objective of this paper is to propose a new unsupervised incremental approach in order to follow the evolution of research themes for a given scientific discipline in terms of emergence or decline. Such behaviors are detectable by various methods of filtering. However, our choice is made on the exploitation of neural clustering methods in a multi-view context. This new approach makes it possible to take into account the incremental and chronological aspects of information by opening the way to the detection of convergences and divergences of research themes at a large scale.

Restricted access

# On the convergence of Kergin and Hakopian interpolants at Leja sequences for the disk

Author: Van Manh Phung

## Abstract

We prove that Kergin interpolation polynomials and Hakopian interpolation polynomials at the points of a Leja sequence for the unit disk D of a sufficiently smooth function f in a neighbourhood of D converge uniformly to f on D. Moreover, when fC (D), all the derivatives of the interpolation polynomials converge uniformly to the corresponding derivatives of f.

Restricted access

# Parallel subtraction of nonnegative forms

Authors: Zoltán Sebestyén and Tamás Titkos

## Abstract

The notions of parallel sum and parallel difference of two nonnegative forms were introduced and studied by Hassi, Sebestyén, and de Snoo in [13] and [14]. In this paper we consider the parallel subtraction with much circumstances. Criteria are established for the solvability of the equation with an unknown when and are given. We identify as the minimal solution, and characterize all the solutions under the assumption where λ>1. The Galois correspondence induced by the map is also studied. We show that if the equation is solvable, then there is a unique -closed solution, namely . Finally, we consider some extremal problems such as the extreme points of the interval , and the characterization of the minimal forms in terms of the parallel sum.

Restricted access

# Planar zero divisor graphs of partially ordered sets

Authors: M. Afkhami, Z. Barati and K. Khashyarmanesh

## Abstract

We associate a graph G (P) to a partially ordered set (poset, briefly) with the least element 0, as an undirected graph with vertex set P =P∖{0} and, for two distinct vertices x and y, x is adjacent to y in G (P) if and only if {x,y}={0}, where, for a subset S of P, S is the set of all elements xP with xs for all sS. We study some basic properties of G (P). Also, we completely investigate the planarity of G (P).

Restricted access

# Polynomial perturbations of transcendental entire functions in the Laguerre–Pólya class

Authors: George Csordas and Chung-Chun Yang

## Abstract

The principal goal of this paper is to investigate and report results concerning the following problem. Determine the family of all real entire functions of positive order, φ, in the Laguerre–Pólya class, such that if p is an arbitrary, non-constant real polynomial which has no zeros in common with φ, then the entire function f=φ+p possesses some non-real zeros. Ramifications of the results obtained are also considered in relation to the Hermite–Poulain Theorem and the theory of multiplier sequences.

Restricted access

Authors: Daniel Ceretto, Esther García and Miguel Gómez Lozano

## Abstract

For an arbitrary group G and a G-graded Lie algebra L over a field of characteristic zero we show that the Kostrikin radical of L is graded and coincides with the graded Kostrikin radical of L. As an important tool for our proof we show that the graded Kostrikin radical is the intersection of all graded-strongly prime ideals of L. In particular, graded-nondegenerate Lie algebras are subdirect products of graded-strongly prime Lie algebras.

Restricted access

# Separation properties at p for the topological category of Cauchy spaces

Author: Muammer Kula

## Abstract

An explicit characterization of each of the separation properties T i, i=0,1, , and T 2 at a point p is given in the topological category of Cauchy spaces. Moreover, specific relationships that arise among the various T i, i=0,1, , and T 2 structures at p are examined in this category. Finally, we investigate the relationships between generalized separation properties and separation properties at a point p in this category.

Restricted access

# Editorial

Author: Tibor Braun
Restricted access

# A bibliometric analysis of solar power research from 1991 to 2010

Authors: Bensi Dong, Guoqiang Xu, Xiang Luo, Yi Cai and Wei Gao

## Abstract

A bibliometric analysis was performed on solar power-related research between 1991 and 2010 in journals of all the subject categories of the Science Citation Index. “Solar cell”, “solar energy”, “solar power”, “solar radiation” and “solar thermal” were selected as keywords to search in a part of the title, abstract or keywords. The trends were analyzed with the retrieved results in the publication type and language, characters of scientific output, publication distribution by countries, subject categories and journals, and the frequency of title-words and keywords used. Articles on solar power showed a significant growth along with more participation of countries, while the percentage of international papers reduced. The USA was the country with the most related articles and the most-frequent partner among all the international collaborative articles. Articles of Mainland China and South Korea grew much faster than other countries in the latest 5 years. Chemistry and material fields gradually became the mainstream of the solar power research. Synthetically analyzing three kinds of keywords, it showed that thin film solar photovoltaic technology was a hot spot of the solar power research in the past 20 years. “Dye-sensitized solar cell” and “organic” had extremely high increasing rates, which indicated that more attention was paid to kinds of organic solar cells. It could be concluded that the materials of solar cells would be the emphasis of solar power research in the twenty-first century.

Restricted access

# Effects of war on scientific production: mathematics in Croatia from 1968 to 2008

Author: Jasna Dravec Braun

## Abstract

Since 1968 the Croatian Mathematical Society has issued annual reports on activities of its members in the scientific journal Glasnik Matematički. Based on these data was analysed production of mathematical scientific articles published in national and international journals in the period of forty years. A rough estimate of the intensity and dynamics of the publication shows that the publication of the reference period can be divided into two stages separated by the War in Croatia. After a period of uncertainty of the 2nd World war the period preceding was characterized by establishing new institutes, colleges and university departments. After the War in Croatia a gradual but large increase in the number of published articles was evident, especially in foreign journals. The War diminished technical writing almost to the zero while increase of scientific production was 9 times greater in 2008 than in 1968.

Restricted access

# Deformation of and -modules of symbols

Authors: Imed Basdouri and Mabrouk Ben Ammar

## Abstract

We consider the -module structure on the spaces of symbols of differential operators acting on the spaces of weighted densities. We compute the necessary and sufficient integrability conditions of a given infinitesimal deformation of this structure and prove that any formal deformation is equivalent to its infinitesimal part. We study also the super analogue of this problem getting the same results.

Restricted access

# Divisibility of class numbers of imaginary quadratic fields whose discriminant has only three prime factors

## Abstract

We prove the existence of infinitely many imaginary quadratic fields whose discriminant has exactly three distinct prime factors and whose class group has an element of a fixed large order. The main tool we use is solving an additive problem via the circle method.

Restricted access

# Erratum to: Research evaluation. Part II: gender effects of evaluation: are men more productive and more cited than women?

Authors: Hildrun Kretschmer, Alexander Pudovkin and Johannes Stegmann
Restricted access

# A generalization of the unit and unitary Cayley graphs of a commutative ring

Authors: Kazem Khashyarmanesh and Mahdi Reza Khorsandi

## Abstract

Let R be a commutative ring with non-zero identity and G be a multiplicative subgroup of U(R), where U(R) is the multiplicative group of unit elements of R. Also, suppose that S is a non-empty subset of G such that S −1={s −1sS}⫅S. Then we define Γ(R,G,S) to be the graph with vertex set R and two distinct elements x,yR are adjacent if and only if there exists sS such that x+syG. This graph provides a generalization of the unit and unitary Cayley graphs. In fact, Γ(R,U(R),S) is the unit graph or the unitary Cayley graph, whenever S={1} or S={−1}, respectively. In this paper, we study the properties of the graph Γ(R,G,S) and extend some results in the unit and unitary Cayley graphs.

Restricted access

# Multiplier sequences for simple sets of polynomials

Authors: T. Forgács, J. Tipton and B. Wright

## Abstract

We give a new characterization of simple sets of polynomials B with the property that the set of B-multiplier sequences contains all Q-multiplier sequences for every simple set Q. We characterize sequences of real numbers which are multiplier sequences for every simple set Q, and obtain some results toward the partitioning of the set of classical multiplier sequences.

Restricted access

# On a question of V. I. Arnol'd

Author: Imre Bárány

## Abstract

We show by a construction that there are at least exp {cV (d−1)/(d+1)} convex lattice polytopes in ℝd of volume V that are different in the sense that none of them can be carried to an other one by a lattice preserving affine transformation.

Restricted access

# Ultracompleteness of hyperspaces of compact sets

Author: Daniel Jardón

## Abstract

A space X is called ultracomplete if it has countable character in its Stone–Čech compactification βX. A space X is called almost locally compact if the set of all points at which X is not locally compact is contained in a compact set of countable outer character. For a given Tychonoff space X let 2X be the hyperspace of all nonempty compact subsets of X endowed with the Vietoris topology. We prove that 2X is almost locally compact if and only if X is locally compact. We also prove that for a countably compact ultracomplete space X the hyperspace F n(X)={K∊2XK has at most n points} is also countably compact ultracomplete for every natural number n. We also analyse ultracompleteness of F n(X) and 2X.

Restricted access

# The contingent nature of brain gain and brain circulation: their foreign context and the impact of return scientists on the scientific community in their country of origin

Author: Thijs A. Velema

## Abstract

The recent literature on high skilled labor migration has taken a turn from analyzing processes of ‘brain drain’ to processes of ‘brain gain’ and ‘brain circulation’. Returning scientists, having been affiliated to foreign institutes, are able to facilitate knowledge exchanges between the two locations, and facilitate the linkage of the national scientific community to international scientific cooperation projects. In this way, return scientists can have a disproportionate impact on the development of the scientific community in their country of origin. However, not all flows of return migrants have had such a positive impact. Returnees failed to affect developments in some localities, while producing ambiguous effects in others. These studies typically argue that the impact of return migrants is dependent on the absorptive capacity and the local social, cultural, and institutional context in the country of origin. Using data on return migrants within the Taiwanese economic academic community, this paper seeks to add to this literature by arguing that the impact of return migrants is not only dependent on the circumstances in their country of origin, but is also contingent on the nature and quality of the context in which they acquired their international labor experience. Skills and access to knowledge networks are heterogeneously spread over geographical space, so that the context in which a return migrant acquired his or her international labor experience matters.

Restricted access

# Gender differences in scientific productivity: a persisting phenomenon?

Authors: Pleun van Arensbergen, Inge van der Weijden and Peter van den Besselaar

## Abstract

There is substantial literature on research performance differences between male and female researchers, and its explanation. Using publication records of 852 social scientists, we show that performance differences indeed exist. However, our case study suggests that in the younger generation of researchers these have disappeared. If performance differences exist at all in our case, young female researchers outperform young male researchers. The trend in developed societies, that women increasingly outperform men in all levels of education, is also becoming effective in the science system.

Restricted access

# In public peer review of submitted manuscripts, how do reviewer comments differ from comments written by interested members of the scientific community? A content analysis of comments written for Atmospheric Chemistry and Physics

Authors: Lutz Bornmann, Hanna Herich, Hanna Joos and Hans-Dieter Daniel

## Abstract

Whereas in traditional peer review a few selected researchers (peers) are included in the manuscript review process, public peer review includes both invited reviewers (who write ‘reviewer comments’) and interested members of the scientific community who write comments (‘short comments’). Available to us for this investigation are 390 reviewer comments and short comments assessing 119 manuscripts submitted to the journal Atmospheric Chemistry and Physics (ACP). We conducted a content analysis of these comments to determine differences in the main thematic areas considered by the scientists in their assessment comments. The results of the analysis show that in contrast to interested members of the scientific community, reviewers focus mainly on (1) the formal qualities of a manuscript, such as writing style, (2) the conclusions drawn in a manuscript, and (3) the future “gain” that could result from publication of a manuscript. All in all, it appears that ‘reviewer comments’ better than ‘short comments’ by interested members of the scientific community support the two main functions of peer review: selection and improvement of what is published.

Restricted access

# Papers written by Nobel Prize winners in physics before they won the prize: an analysis of their language and journal of publication

Authors: Caifeng Ma, Cheng Su, Junpeng Yuan and Yishan Wu

## Abstract

In this paper, we analyzed data relating to the language of papers written by winners of Nobel Prizes in physics before they won the prize and their journals of publication, and we identified the change in scientific language corresponding with shifts of the center of the scientific world. Using the science citation index as the main data source, we also collected information on the distribution of prize-winning scientists by country, by each scientist's number of published papers, and by language. We then analyzed their papers in terms of the different journals based in different countries. The results are presented in three parts: (1) the main languages used in the papers are English and German. The proportion of papers in English is gradually increasing, while that of papers in German is decreasing. (2) The prize winning scientists’ papers have been published mainly in journals in their own nation and in the United States. (3) Journals based in their own countries are very helpful to these scientists early in their careers.

Restricted access

# Properties of journal impact in relation to bibliometric research group performance indicators

Author: Anthony F. J. van Raan

## Abstract

In this paper we present a compilation of journal impact properties in relation to other bibliometric indicators as found in our earlier studies together with new results. We argue that journal impact, even calculated in a sufficiently advanced way, becomes important in evaluation practices based on bibliometric analysis only at an aggregate level. In the relation between average journal impact and actual citation impact of groups, the influence of research performance is substantial. Top-performance as well as lower performance groups publish in more or less the same range of journal impact values, but top-performance groups are, on average, more successful in the entire range of journal impact. We find that for the high field citation-density groups a larger size implies a lower average journal impact. For groups in the low field citation-density regions however a larger size implies a considerably higher average journal impact. Finally, we found that top-performance groups have relatively less self-citations than the lower performance groups and this fraction is decreasing with journal impact.

Open access

# Ranking of research output of universities on the basis of the multidimensional prestige of influential fields: Spanish universities as a case of study

Authors: J. A. García, Rosa Rodriguez-Sánchez, J. Fdez-Valdivia, Daniel Torres-Salinas and Francisco Herrera

## Abstract

A university may be considered as having dimension-specific prestige in a scientific field (e.g., physics) when a particular bibliometric research performance indicator exceeds a threshold value. But a university has multidimensional prestige in a field of study only if it is influential with respect to a number of dimensions. The multidimensional prestige of influential fields at a given university takes into account that several prestige indicators should be used for a distinct analysis of the influence of a university in a particular field of study. After having identified the multidimensionally influential fields of study at a university their prestige scores can be aggregated to produce a summary measure of the multidimensional prestige of influential fields at this university, which satisfies numerous properties. Here we use this summary measure of multidimensional prestige to assess the comparative performance of Spanish Universities during the period 2006–2010.

Restricted access

# A reassessment of Asian pacific excellence programs in higher education: the Taiwan experience

Authors: Angela Yung-Chi Hou, Martin Ince and Chung-Lin Chiang

## Abstract

With the growth of competition between nations in our knowledge-based world economy, excellence programs are becoming a national agenda item in developing as well as developed Asian countries. The main purpose of this paper is to compare the goals, funding policies and selection criteria of excellence programs in China, Japan, Korea and Taiwan and to analyze the academic achievement of their top ranked universities in three areas: research output, internationalization, and excellence, by using data from the Shanghai Jiao Tong, QS, and HEEACT rankings. The effectiveness of Taiwan's “Development Plan for World Class Universities and Research Centers of Excellence” was assessed as a case study in the paper via a survey targeting on 138 top administrators from 11 Taiwan's universities and 30 reviewers. The study found that more funding nations had, the more outputs and outcomes they would gain, for example China. The Taiwan case demonstrates that world-class universities and research centers are needed in Asian nations despite the concerns for inequality which they raise.

Restricted access

# Visibility in international rankings. Strategies for enhancing the competitiveness of Spanish universities

Authors: Daniel De Filippo, Fernando Casani, Carlos García-Zorita, Preiddy Efraín-García and Elías Sanz-Casado

## Abstract

The world-wide popularity of university rankings has spurred the debate about the quality and performance of higher education systems and has had a considerable impact on global society in light of the internationalisation of higher education. While useful for policy makers, such rankings also furnish information on an institution's “prestige”, which may in turn contribute to more effective resource capture (students, funding, projects). Certain university profiles and missions may prevent many universities from climbing to higher positions, however. One important question in this regard is: how many of a country's universities can stand at the top of international rankings? The present article attempts to answer this question on the grounds of a study of the Spanish higher education system, and more specifically of an institutional alliance consisting of four high quality universities. A series of research activity indicators drawn from the IUNE Observatory are used to compare this alliance to leading Spanish and international universities and explore whether their visibility and consequently their position in international rankings would be enhanced if they were able to appear under a joint identity. This prospective study also addresses a series of strategies that the Spanish higher education system might implement to successfully rise to the challenges posed by future scenarios.

Restricted access

# Strategic partnership and its effect on external learning of technology descendants

Authors: Jennifer H. Chen, Shihmin Lo, Show-Ling Jang and Chi-Cho Huang

## Abstract

We examine how strategic partnership affects external learning of technology descendants from emerging markets under the context of Taiwan's flat panel display industry. The study takes patent citation as a trail of knowledge flow, and incorporates 1,726 pairs relations of the cited and citing firms. Our empirical evidence shows positive pattern of external learning through strategic technology partnership. After controlling the quality factor of the knowledge, technology descendants do learn more from their alliance partners than other non-allied firms; particularly, trading type of partnerships characterized by the asymmetric relations appears to bring more impact. Furthermore, a focused approach in extrapolating knowledge from strategic partners seems to be the dominant practice.

Restricted access

# Scientific production and citation impact: a bibliometric analysis in acupuncture over three decades

Authors: Jun-Ying Fu, Xu Zhang, Yun-Hua Zhao, He-Feng Tong, Dar-Zen Chen and Mu-Hsuan Huang

## Abstract

Acupuncture, the most important nonpharmacological therapy in traditional Chinese medicine, has attracted significant attention since its introduction to the Western world. This study employs bibliometric analysis to examine the profile of publication activity related to it. The data are retrieved from the database of Science Citation Index Expanded during 1980–2009, and 7,592 papers are identified for analysis. This study finds that almost 20 % of papers are published in CAM journals, and the average cited times per acupuncture paper is 8.69. While the most cited article has been cited 2,109 times, however, 38.15 % of total publications have never been cited. Europe has the largest amount of authored papers with high h-index values; the USA has the largest number of publications on and citations of acupuncture based on country distribution, and this has continued as a significant rising trend. The proportion of collaborative papers shows this upward trend on the worldwide scale while the percentage shares of national collaborations are the highest. The USA produces the most international collaborative documents, although South Korea occupies the highest percentage figure for international collaborative papers. International collaborative papers are the most frequently cited. The average number of authors per paper is 3.69 in the top eight countries/regions. Papers contributed by South Korea are authored by the most people. International collaboration papers are authored by more people, except in Taiwan. South Korea's Kyung Hee University is ranked first in terms of number of papers while Harvard University in the USA accounts for the largest proportion of citations. The University of Exeter, Harvard University and Karolinska Institute have the highest h-index values.

Restricted access

# Bibliometric characteristics of highly cited papers from Taiwan, 2000–2009

Authors: Nobuko Miyairi and Han-Wen Chang

## Abstract

The present study analyzes bibliometric characteristics of Taiwan's highly cited papers published from 2000 to 2009. During this period, Taiwan ranked within the top 30 countries by number of highly cited papers, defined in Thomson Reuters’ Essential Science Indicators (ESI) as those that rank in the top 1 % by citations for their category and year of publication. Taiwan made notable progress in world-class research in the two consecutive 5-year periods 2000–2004 and 2005–2009. For the group of highly cited papers from Taiwan, USA, China, Germany, and Japan were the top collaborating countries over the decade. In recent years, Taiwan has increasingly collaborated with European countries whose output of highly cited papers is relatively high and increasing, rather than with its neighboring countries in Asia. Overall, Taiwan produced highly cited papers in all the 22 ESI subject categories during the 10-year period. Taiwan's output of highly cited papers was greatest in the categories of Engineering, Clinical Medicine, and Physics, while those in Agricultural Sciences and Mathematics exceeded the expected output level in relative terms. More detailed analyses would be useful for a holistic understanding of Taiwan's research landscape and their progress in world-class research, combining both bibliometric and non-bibliometric data, such as researcher mobility, research grants, and output from internationally-collaborated research programs.

Restricted access

# The growth of science and database coverage

Authors: Carolin Michels and Ulrich Schmoch

## Abstract

Recently there has been huge growth in the number of articles displayed on the Web of Science (WoS), but it is unclear whether this is linked to a growth of science or simply additional coverage of already existing journals by the database provider. An analysis of the category of journals in the period of 2000–2008 shows that the number of basic journals covered by Web of Science (WoS) steadily decreased, whereas the number of new, recently established journals increased. A rising number of older journals is also covered. These developments imply a crescive number of articles, but a more significant effect is the enlargement of traditional, basic journals in terms of annual articles. All in all it becomes obvious that the data set is quite instable due to high fluctuation caused by the annual selection criteria, the impact factor. In any case, it is important to look at the structures at the level of specific fields in order to differentiate between “real” and “artificial” growth. Our findings suggest that even-though a growth of about 34 % can be measured in article numbers in the period of 2000–2008, 17 % of this growth stems from the inclusion of old journals that have been published for a longer time but were simply not included in the database so far.

Restricted access

# Patent litigation precaution method: analyzing characteristics of US litigated and non-litigated patents from 1976 to 2010

Authors: Hsin-Ning Su, Carey Ming-Li Chen and Pei-Chun Lee

## Abstract

This study aims to propose an early precaution method which allows predicting probability of patent infringement as well as evaluating patent value. To obtain the purposes, a large-scale analysis on both litigated patents and non-litigated patents issued between 1976 and 2010 by USPTO are conducted. The holistic scale analysis on the two types of patents (3,878,852 non-litigated patents and 31,992 litigated patents in total) issued by USPTO from 1976 to 2010 has not been conducted in literatures and need to be investigated to allow patent researchers to understand the overall picture of the USPTO patents. Also, by comparing characteristics of all litigated patents to that of non-litigated patents, a precaution method for patent litigation can be obtained. Both litigated patents and non-litigated patents are analyzed to understand the differences between the two types of patents in terms of different variables. It is found that there are statistically significant differences for the two types of patents in the following 11 variables: (1) No. of Assignee, (2) No. of Assignee Country, (3) No. of Inventor, (4) Inventor Country, (5) No. of Patent Reference, (6) No. of Patent Citation Received, (7) No. of IPC, (8) No. of UPC, (9) No. of Claim, (10) No. of Non-Patent Reference, and (11) No. of Foreign Reference. Finally, logistic regression is used for predicting the probability of occurrence of a patent litigation by fitting the 11 characteristics of 3,910,844 USPTO patents to a logistic function curve.

Restricted access

# The development and empirical study of a literature review aiding system

Author: Tsung Teng Chen

## Abstract

Literature review is an important but time-consuming task that involves many disparate steps. A simple query to a library database may return voluminous literature that often bewilders novices. We believe the bibliographic techniques developed by the information scientists provide useful process and methods that facilitate literature analysis and review. We thereby developed a citation-based literature analyzing and structuring system, which may facilitate novices to perform tasks that are usually carried out by trained professionals. A field study was carried out to gauge the utility as well as users’ perception using a questionnaire adopted from relevant empirical studies. Graduate students participated in the field study are able to publish papers in their first semester by utilizing this system. The utility and usefulness of the intellectual structuring system are demonstrated by the objective evidence of the high acceptance rate of papers utilizing the system as well as the subjective positive response from the users. A system utilization model utilizing the structure equation modeling technique found the task characteristics construct affects the information quality construct, which in turn affects the perceive usefulness of the system.

Restricted access

# Economic, linguistic, and political factors in the scientific productivity of countries

Author: Ernesto R. Gantman

## Abstract

This paper examines the influence of economic, linguistic, and political factors in the scientific productivity of countries across selected scientific disciplines. Using a negative binomial regression model, I show that the effect of these determinants is contingent upon the scientific field under analysis. The only variable that exerts a positive and significant effect across all disciplines is the size of the economy. The linguistic variable only has a positive influence in the social sciences as well as in medicine and agricultural sciences. In addition, it is also demonstrated that the degree of political authoritarianism has a negative and statistically significant effect in some of the selected fields.

Restricted access

# Evaluating journal performance metrics

Author: Gangan Prathap