Egghe, L (Egghe, L.) Item-time-dependent Lotkaian informetrics and applications to the calculation of the time-dependent h-index and g-index MATHEMATICAL AND COMPUTER MODELLING, 45 (7-8): 864-872 APR 2007

[Eugene Garfield]

E-mail Address: leo.egghe at uhasselt.be 

Author(s): Egghe, L (Egghe, L.) 

Title: Item-time-dependent Lotkaian informetrics and applications to the 
calculation of the time-dependent h-index and g-index 

Source: MATHEMATICAL AND COMPUTER MODELLING, 45 (7-8): 864-872 APR 2007 

Language: English 

Document Type: Article 

Author Keywords: Lotka; Lotkaian informetrics; time-dependent; h-index; 
Hirsch; g-index 

Keywords Plus: HIRSCH-INDEX; INDICATORS; SCIENTISTS; RANKING 

Abstract: The model for the cumulative nth citation distribution, as 
developed in [L. Egghe, I.K. Ravichandra Rao, Theory of first-citation 
distributions and applications, Mathematical and Computer Modelling 34 
(2001) 81-90] is extended to the general source-item situation. This 
yields a time-dependent Lotka function based on a given (static) Lotka 
function (considered to be valid for time t = infinity). Based on this 
function, a time-dependent Lotkaian informetrics theory is then further 
developed by e.g. deriving the corresponding time-dependent rank-frequency 
function.
These tools are then used to calculate the dynamical (i.e. time-dependent) 
g-index (of Egghe) while also an earlier proved result on the time-
dependent h-index (of Hirsch) is refound. It is proved that both indexes 
are concavely increasing to their steady state values for t = infinity. 
(c) 2006 Elsevier Ltd. All rights reserved. 

Addresses: Univ Hasselt, B-3590 Diepenbeek, Belgium; Univ Antwerp, B-2610 
Antwerp, Belgium 

Reprint Address: Egghe, L, Univ Hasselt, Campus Diepenbeek, B-3590 
Diepenbeek, Belgium. 

Cited Reference Count: 17 

Times Cited: 0 

Publisher: PERGAMON-ELSEVIER SCIENCE LTD 

Publisher Address: THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 
1GB, ENGLAND 

ISSN: 0895-7177 

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