Representation for Evolution of Epidemic Models

Abstract

Creating a representation capable of generating personal contact networks that are most likely to exhibit specific epidemic behavior is difficult due to the inherit volatility of an epidemic and the numerous parameters accompanying the problem. To surpass these hurdles, evolutionary algorithms are used to create a generative solution which generates personal contact networks, modeling human populations, to satisfy the epidemic duration and epidemic profile matching problems. This representation is entitled the Local THADS-N representation. Two new operators are added to the original THADS-N system, and tested with a traditional parameter sweep and a parameter selection method known as point packing on nine epidemic profiles. Additionally, a new epidemic model is implemented in order to allow for lost immunity within a population thus increasing the length of an epidemic.

Modelling of Vaccination Strategies for Epidemics using Evolutionary Computation

“…These added operations improved performance, leading to exploration of several new operations. Beneficial ones were incorporated into the representation [8], [10]- [12]. The newest operations added are local edge operations as they ensure that the triples of vertices involved within the operation will maintain a minimum distance of two from one another before and after the editing operation is applied.…”

“…To run this algorithm, a researcher must choose a value for the minimum allowable distance between parameter settings. The 29 parameter settings used here come from [12], and correspond to a minimum distance of 0.535.…”

“…One change to the tournament selection used in this paper is the re-evaluation of the fitness of the two chromosomes after being copied to make the parent chromosomes. This procedure, known as skeptical tournament selection, was first described in [21] and has been shown to be useful in [10]- [12]. This process does not indicate the absolute quality of a network, but instead its relative quality, permitting successive solutions to converge to graphs which are more likely to create epidemics satisfying the problem at hand.…”

“…The epidemic duration (ED) problem [4] seeks to find graphs which promote longer-lasting epidemics. In considering the epidemic duration problem, previous work [12] generated a large number of graphs. As a first step in the current study, we take the best 30 of these, i.e.…”

“…The mean epidemic length, with 95% confidence interval, of epidemics unleashed on the 30 best personal contact networks for each of the 29 parameter settings with the specified vaccination strategy. The personal contact networks are from [12]. Fig.…”