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Architecture of Computing Systems (Lecture Notes in Computer ...

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Ad-Hoc Information Spread between Mobile<br />

Devices: A Case Study <strong>in</strong> Analytical Model<strong>in</strong>g <strong>of</strong><br />

Controlled Self-organization <strong>in</strong> IT <strong>Systems</strong><br />

Kamil Kloch 1 ,JanW.Kantelhardt 2 ,PaulLukowicz 1 ,PatrickWüchner 3 ,<br />

and Hermann de Meer 3<br />

1 Embedded <strong>Systems</strong> Lab, University <strong>of</strong> Passau, Innstraße 43,<br />

D-94032 Passau Germany<br />

2 Institut für Physik, Mart<strong>in</strong>-Luther-Universität Halle-Wittenberg,<br />

D-06099 Halle (Saale) Germany<br />

3 <strong>Computer</strong> Networks and <strong>Computer</strong> Communications, University <strong>of</strong> Passau,<br />

Innstraße 43, D-94032 Passau Germany<br />

Abstract. We present an example <strong>of</strong> the use <strong>of</strong> analytical models to predict<br />

global properties <strong>of</strong> large-scale <strong>in</strong>formation technology systems from<br />

the parameters <strong>of</strong> simple local <strong>in</strong>teractions. The example is <strong>in</strong>tended as<br />

a first step towards us<strong>in</strong>g complex systems model<strong>in</strong>g methods to control<br />

self-organization <strong>in</strong> organic systems. It is motivated by a concrete application<br />

scenario <strong>of</strong> <strong>in</strong>formation distribution <strong>in</strong> emergency situations, but is<br />

relevant to other doma<strong>in</strong>s such as malware spread or social <strong>in</strong>teractions.<br />

Specifically, we show how the spread <strong>of</strong> <strong>in</strong>formation through ad-hoc <strong>in</strong>teractions<br />

between mobile devices depends on simple local <strong>in</strong>teraction rules<br />

and parameters such as user mobility and physical <strong>in</strong>teraction range. We<br />

show how three qualitatively different regimes <strong>of</strong> <strong>in</strong>formation ‘<strong>in</strong>fection<br />

rate’ can be analytically derived and validate our model <strong>in</strong> extensive<br />

simulations.<br />

1 Introduction<br />

In this paper we present a specific example <strong>of</strong> the adaptation <strong>of</strong> an analytical<br />

complex system model to a self-organiz<strong>in</strong>g IT system. We show how logistic<br />

models from epidemiology can be applied to describe the spread <strong>of</strong> <strong>in</strong>formation<br />

or malware between mobile phones carried by people mov<strong>in</strong>g <strong>in</strong> a crowd. We<br />

derive the dependence <strong>of</strong> <strong>in</strong>formation penetration on crowd density, radio range,<br />

and motion speed. We show a ‘phase transition’-like behavior: <strong>in</strong>formation is<br />

be<strong>in</strong>g spread with the speed either l<strong>in</strong>early <strong>in</strong>creas<strong>in</strong>g with the radio range,<br />

almost constant, or approximately exponentially. Another parameter-dependent<br />

emergent effect is the transition between local but dy<strong>in</strong>g ‘<strong>in</strong>formation bubbles’<br />

and a cont<strong>in</strong>uous spread <strong>of</strong> <strong>in</strong>formation. The model is validated us<strong>in</strong>g extensive<br />

simulations show<strong>in</strong>g good agreement with analytical predictions.<br />

The value <strong>of</strong> the research presented <strong>in</strong> this paper is threefold:<br />

First, on application level, it is part <strong>of</strong> a large, <strong>in</strong>terdiscipl<strong>in</strong>ary EU project (SO-<br />

CIONICAL, http://socionical.eu) to understand and exploit self-organization <strong>in</strong><br />

C. Müller-Schloer, W. Karl, and S. Yehia (Eds.): ARCS 2010, LNCS 5974, pp. 101–112, 2010.<br />

c○ Spr<strong>in</strong>ger-Verlag Berl<strong>in</strong> Heidelberg 2010

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