Formal vs self-organised knowledge systems: a network approach

In this work we consider the topological analysis of symbolic formal systems in the framework of network theory. In particular we analyse the network extracted by Principia Mathematica of B. Russell and A.N. Whitehead, where the vertices are the statements and two statements are connected with a directed link if one statement is used to demonstrate the other one. We compare the obtained network with other directed acyclic graphs, such as a scientific citation network and a stochastic model. We also introduce a novel topological ordering for directed acyclic graphs and we discuss its properties in respect to the classical one. The main result is the observation that formal systems of knowledge topologically behave similarly to self-organised systems.Comment: research pape

Life, Death and Preferential Attachment

Scientific communities are characterized by strong stratification. The highly skewed frequency distribution of citations of published scientific papers suggests a relatively small number of active, cited papers embedded in a sea of inactive and uncited papers. We propose an analytically soluble model which allows for the death of nodes. This model provides an excellent description of the citation distributions for live and dead papers in the SPIRES database. Further, this model suggests a novel and general mechanism for the generation of power law distributions in networks whenever the fraction of active nodes is small.Comment: 5 pages, 2 figure

Maps of random walks on complex networks reveal community structure

To comprehend the multipartite organization of large-scale biological and social systems, we introduce a new information theoretic approach that reveals community structure in weighted and directed networks. The method decomposes a network into modules by optimally compressing a description of information flows on the network. The result is a map that both simplifies and highlights the regularities in the structure and their relationships. We illustrate the method by making a map of scientific communication as captured in the citation patterns of more than 6000 journals. We discover a multicentric organization with fields that vary dramatically in size and degree of integration into the network of science. Along the backbone of the network -- including physics, chemistry, molecular biology, and medicine -- information flows bidirectionally, but the map reveals a directional pattern of citation from the applied fields to the basic sciences.Comment: 7 pages and 4 figures plus supporting material. For associated source code, see http://www.tp.umu.se/~rosvall

Society's needs in scientific and technical information

Processa-se, presentemente, uma segunda revolução na transmissão da informação científica, comparável, talvez, ao advento do periódico científico. A rapidez de comunicação na frente de pesquisa não mais depende do sistema de comunicação da literatura periódica, que permanece, no entanto, o principal veículo para o registro do conhecimento científico. Um sistema moderno poderia incluir um periódico diário, para rápida disseminação, e também um conjunto de periódicos baseado em uma coleção de documentos reestruturado em classes, de acordo com correlação de citações. Desta forma, os processos de utilização, e validade seriam separados dos cie acumulação do registro científico, em vez de combinados, como acontece no presente sistema. As técnicas bibliométricas atuais tornam tal estrutura possível. Abstract A second revolution in the transmission of scientific information, perhaps comparable to the advent of the scientific journal is presently underway. Rapid research front communication is no longer dependent upon the journal communication system which remains, however, the key record of the accumulation of scientific knowledge. A modern system might well include a daily newspaper format for high speed dissemination and a restructured set of journals based on the collection of papers into classes on the basis of their citation linkages. The processes of use and validation would thus be separated from that of the cumulation of scientific record, rather than combined as in the present system. Current bibliometric techniques make such a structure possible

Studies in Scientometrics I Transience and Continuance in Scientific Authorship

Estuda o fenômeno de transiência/permanência na frente de pesquisa pela análise do fluxo anual de autores de uma população amostrada derivada do banco de dados resultante de sete anos de publicação de "Science Citation Index" e "Who is publishing in Science". Para o período total analisado (1964-1970) foram encontrados 281 autores transientes e 19 autores permanentes, numa população total de 506 autores. Derivou-se, a seguir, um modelo para análise quantitativa do fluxo padrão de autores, verificando-se que há uma taxa de natalidade ("annual recruitment") e uma taxa de mortalidade ("annual terminatio") de cuja superposição resulta uma taxa de mortalidade infantil (transiência). O modelo final permite definir a existência de um núcleo de autores altamente permanentes, correspondente a 20% da população. Os autores transientes constituem 22% da população anual e 2/3 dos autores novos ("newcomers"). Foram ainda identificadas outras categorias de autores na comunidade científica. Há uma clara correlação entre estas propriedades demográficas e as taxas (maior e menor) de produtividade dos autores, cuja distribuição é consistente com as leis de Lotka e Price. Isto permite derivar a expectativa de permanência na frente de pesquisa, que será proporcional ao tempo ativo de publicação. Temos de um lado da escala, a maioria dos autores com uma expectativa de vida mínima e taxa de produtividade baixa (75% dos autores produzindo 25% dos trabalhos); no lado oposto estão os autores do núcleo permanente (20%), com menor taxa de mortalidade e maior taxa de produtividade (mais que a metade dos trabalhos). Esta situação é resultante de um feedback positivo ou efeito Matthew — e parece ser tão intrínseca que, tudo leva a crer, nossa sociedade deve atingir de modo a adaptar sua estrutura institucional à feição da produtividade e demografia científicas. Abstract Investigation of the transience / continuance phenomenon occurring at a research front. The annual output of authors in a random sample derived from seven years data from Science Citation Index and Who is publishing in Science was analysed. In the whole period (1964-1970) there are 281 transient authors and 19 continuant authors, for a total population of 506 authors. By deriving a quantitative model for the author flow pattern analysis, it was shown that there is a birth rate (annual recruitment) and a death rate (annual termination) which overlap to give an infant mortality (transience). By refining the model, it was possible to define a core of continuant authors, which amounts to 20% of those publishing. The transient authors constitute 22% of the annual population and 2/3 of the newcomers to publication. The other identified components of a scientific community are the recruits, terminators, non-core publishing continuants and non-publishing continuants. These demographic properties are clearly associated with the lowest and highest rates of  authors' productivity, the distributions of which folkw Lotka's and Price's laws with great regularity. Thus it was possible to derive a lifetime expectancy at the research front which will be proportional to the time of active publication. On one end of the scale there is a majority of authors with a minimum life expectancy and a low average productivity (75% of the authors produce 25% of the papers); at the opposite extreme there are authors in the permanent nucleus (20%) with less average mortality and greater average productivity (more than half of the papers) All this is a result of the positive feedback or Mathew Principle in scientific publication. This situation seems so intrinsic that it must be regarded at the way in which society has adjusted its institutional structure to fit the cloth of scientific productivity and demography

Studies in scientometrics II. The relation between source author and cited author populations

Uma sequência anual de Citation Indexes mantém um padrão de comportamento em muito semelhante a uma sequência de Source Indexes. Cinco anos do Source Index (1964-1968) foram considerados como suficientes para distinguir, entre os autores, as classes de transientes e permanentes, e três anos do Citation Index (1966-1968) para identificar referências a autores iniciando publicação no começo do período. O arquivo listou 640 autores, dos quais 381 estavam incluídos nos cinco Source Indexes e 442 nos três Citation Indexes, sendo 183 nomes comuns a ambas categorias de índices. Dos autores transientes que aparecem apenas em um único Source Index, 71% não são citados, 19% são transitoriamente citados e somente 10% parecem ser permanentes em citação.Um autor transiente tem cerca de 30% de chance de ser citado em qualquer ano. Do núcleo de 22 autores permanentes que publicam nos cinco anos registrados,19 são também citados em todos os três anos. É importante notar que esses mesmos 19 autores são também aqueles que continuam não apenas por um períodode 5 anos mas pelo período de 7 anos registrados noestudo anterior. Os autores permanentes do Sourcetendem a ser permanentes também em citação. Um grupo de 259 autores que são citados não aparece entre os autores-fonte. Desses, 80% são transientes e 20%são permanentes. Com a edição de novos dados de citação e de características de grupos de autores não incluídos no Source, os grupos demográficos são distribuídos nas seguintes categorias: a) transientes, b) permanentes que não fazem parte do núcleo, c) permanentes integrantes ao núcleo, d) permanentes que continuam a ser citados embora não mais publiquem,e) antigos transientes e f) novos permanentes. Abstract A sequence of annual Citation Indexes behaves in very much the same way as the sequence of Source Indexes. Five years o f Source Index were regarded (1964-1968) as sufficient to distinguish the transient and continuant classes amongst the authors,and three years o f the Citation Index (1966-1968) to pick up references to authors commencing publication at the begining of the period. The file listed 640 authors of which 381 were in the five Source Indexes and 442 in the three Citation Indexes with 183 names being common to both sets of index.O f the transient authors who appear in only a single Source Index 71% are uncited, 19% are transiently cited and only 10% seem to be continuants in citation. A transient author has about 30% chance of being cited in any year. Of the core continuant authors who publish in ali five years of record, 19 of the 22 are also cited in all the three years. It's worth noting that these 19 authors are also those who continue not merely for a five year span but for the seven years recorded in the previous study. Continuant source authors have astrong tendency to be continuants also in citation.A considerable group of 259 names in Citation Index do not appear amongst the source authors. Of the 259 names 80% are transiently cited and 20% are continuants. With the addition of new citation data and the characteristics oft he non-sourcegroups, not before detected, the demographic groups now become as: a) transients b) non-core continuants c) core continuants d) terminated continuants e) former transients f) newly recruited continuants

Correlations in Networks associated to Preferential Growth

Combinations of random and preferential growth for both on-growing and stationary networks are studied and a hierarchical topology is observed. Thus for real world scale-free networks which do not exhibit hierarchical features preferential growth is probably not the main ingredient in the growth process. An example of such real world networks includes the protein-protein interaction network in yeast, which exhibits pronounced anti-hierarchical features.Comment: 4 pages, 4 figure

Matching authors and readers of scientific papers

A novel service is proposed to help authors of scientific papers to select journals to which to submit their manuscripts. The aim of the service is to optimize the common interests of authors, readers/users, and science, by providing the authors with a tool for reaching those readers who can most benefit from the news of their accomplishments. The five basic factors which intervene in the choice of a journal are analyzed: relevance, acceptance rate, circulation, prestige and publication lag. With the help of a mathematical model, we show how these five variables can be used in a plausible decision procedure leading to the selection of journals suitable for the publication of given papers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22360/1/0000806.pd

A bibliometric analysis of the Journal of Molecular Graphics and Modelling

This paper reviews the articles published in Volumes 2-24 of the Journal of Molecular Graphics and Modelling (formerly the Journal of Molecular Graphics), focusing on the changes that have occurred in the subject over the years, and on the most productive and most cited authors and institutions. The most cited papers are those describing systems or algorithms, but the proportion of these types of article is decreasing as more applications of molecular graphics and molecular modelling are reported

A stochastic model for the evolution of the Web

Recently several authors have proposed stochastic models of the growth of the Web graph that give rise to power-law distributions. These models are based on the notion of preferential attachment leading to the "rich get richer" phenomenon. However, these models fail to explain several distributions arising from empirical results, due to the fact that the predicted exponent is not consistent with the data. To address this problem, we extend the evolutionary model of the Web graph by including a non-preferential component, and we view the stochastic process in terms of an urn transfer model. By making this extension, we can now explain a wider variety of empirically discovered power-law distributions provided the exponent is greater than two. These include: the distribution of incoming links, the distribution of outgoing links, the distribution of pages in a Web site and the distribution of visitors to a Web site. A by-product of our results is a formal proof of the convergence of the standard stochastic model (first proposed by Simon)