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Automn 2006-2009

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Levy Walk Model

Levy walk is similar to random walk, but its walk time (flight time) and pause time are more complex. Each step is a tuple S=(l,q,Dtf,Dtp). In this model, each node takes a random direction q, and a flight length l. These values specify a destination point in or out the map. Dtf indicates the flight duration and picked for each flight from a probability distribution p(l). Using the Dtf and l, the model calculates speed of flight. Dtp specifies pause time at the end of a flight and it will be calculated using a configurable distribution y(Dtp).

In order to create random numbers for needed distributions, I used random generator algorithm presented in MATLAB codes that model creators uploaded in http://netsrv.csc.ncsu.edu/twiki/bin/view/Main/MobilityModelsDnld. The random generator needs some parameters which follow:

  • minflight & maxflight: specifying the range of flight length.
  • alpha
  • beta
  • minpausetime & maxpausetime: specifying the range of pause time at the end of flight.
  • flightscale.

Levy Walk

Figure 29: Traveling pattern of nodes in Levy Walk model

Levy Walk

Figure 30: Spatial node distribution in Levy Walk model

 
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Masoud Moshref Javadi © 2007