Presents definitions of convolutions, mathematical operations between sequences or between functions, and gives examples of their use in information science. In particular they can be used to explain the decline in the use of older literature (obsolescence) or the influence of publication delays on the aging of scientific literature. (Author/LRW)

Discusses graph theory in information science, focusing on measures for the cohesion of networks. Illustrates how a set of weights between connected nodes can be transformed into a set of dissimilarity measures and presents an example of the new compactness measures for a cocitation and a bibliographic coupling network. (Author/LRW)

Examines the notions of aging, obsolescence, impact, growth, utilization, and related concepts in information science. Illustrates the influence of growth on aging, how aging rates can be corrected for growth, and the relation with impact measures. Presents mathematical results, practical calculations, and examples of these concepts. Gives a brief…

Discusses topological aspects of theoretical information retrieval, including retrieval topology; similarity topology; pseudo-metric topology; document spaces as topological spaces; Boolean information retrieval as a subsystem of any topological system; and proofs of theorems. (LRW)

Proposes a mathematical model to explain the observed concentration or diversity of nominal classes in information retrieval systems. The Lorenz Curve is discussed, Information Production Process (IPP) is explained, and a heuristic explanation of circumstances in which the model might be used is offered. (30 references) (LRW)

Duality is an important topic in informetrics, often less studied in information retrieval where it relates to the unification or symmetry of queries and documents, search formulation versus indexing, and relevant versus retrieved documents. This article examines duality in information retrieval and highlights its connection with hypergeometric…

Discusses science evaluation studies that seek to determine quantitatively the contribution of different authors, departments, or countries to the whole system, and suggests that different scoring methods can yield totally different rankings. Presents formulas for counting procedures, nontrivial examples of anomalies, and possible solutions.…

Discusses synchronous impact factors and theoretical models derived from observations based on "Science Citation Index", and presents an exception to the general rules based on data from the "Chinese Science Citation Database". Considers that the observed discrepancies could be statistical fluctuations of the basic…

This article offers comments and clarifications of Egghe's paper, which dealt with information production processes (IPP) and the Gini index. Topics addressed include the length of the Lorenz curve as a concentration measure, the discrete duality operator, and a Bradford-Leimkuhler distribution. (10 references) (LRW)

Discussion of impact factors for "Journal Citation Reports" subject categories focuses on the difference between an average of quotients and a global average, obtained as a quotient of averages. Applications in the context of informetrics and scientometrics are given, including journal prices and subject discipline influence scores.…

Reformulates the success-breeds-success (SBS) principle in informetrics in order to generate a general theory of source-item relationships. Topics include a time-dependent probability, a new model for the expected probability that is compared with the SBS principle with exact combinatorial calculations, classical frequency distributions, and…

Discusses the influence of publication delays on the aging of scientific literature and explains how the undisturbed aging function and the publication delay combine to give the observed aging function through a mathematical operation called convolution. Shows the convolution of various distributions and considers a paradox between theory and real…

Relative own-language preference (ROLP) depends on: the publication share of the language and the self-citing rate. ROLP and the openness of one language with respect to another can be represented by partial order. Logarithmic dependence on the language share(s) seems a natural additional requirement for measuring language preferences. Gives…

Describes a direct linear relation between the number of articles in a journal and the journal's impact factor. Hypotheses are presented; theoretical considerations are discussed; and results are described that show exceptions for review journals and translation journals, as well as for journals in mathematics and chemistry. (Author/LRW)

Demonstrates how the addition of a third "hidden" variable to the two parameters in Lotka's law makes this law equivalent, in a strictly logical sense, with Mandelbrot's law. Similarly, Lotka's inverse square law is made equivalent with Leimkuhler's law. It is also shown how Pareto's law fits into this framework. (29 references)…