## LSU Historical Dissertations and Theses

#### Title

On Information Usage Modeling.

1994

Dissertation

#### Degree Name

Doctor of Philosophy (PhD)

Ye-Sho Chen

#### Abstract

Although it is well-known that the usage of information usually follows the 80/20 rule and concentrates on a few items, there has not been an analytical model to depict this skew distribution. This dissertation provides a theoretical foundation, based on Simon's modeling of empirical phenomena and Chen's index approach, to identify the factors which shape this usage pattern. Using Chen's index approach, we conclude that the distance and slope of the data points determine the shape of the distribution. We further examine the critical parameters in Simon's model through computer simulations, and we find the probability of new entry ($\alpha$) and the rate of "decay" ($\beta$) to be two predominant factors that affect the patterns of information usage. Based on the effects of these two parameters we can establish the limiting conditions under which these empirical phenomena hold true. Finally, we show how our findings can be applied to enhance the weeding process in libraries--a procedure that can be extended to the archive management of information systems.

143

COinS