CRESCO SPIII.5 Project status 06-07-07

Dip. Di Informatica Sistemi e Produzione Università di Roma Tor Vergata

E. Casalicchio, E.Galli, S.Tucci

CRESCO SPIII.5Project status 06-07-07

Università di Roma "Tor Vergata" - CRESCO-SPIII

What's an Agent

2

It's a software process able to work asynchrounsly and autonously in an particular environment

An agent is identifiable, a discrete individual with a set of characteristics and rules governing its behaviors and decision-making capability.

It can perceive and interact with the world (environment and other agents)Agents have protocols for interaction with other

agents Every agent is identified by an own location,

capabilities and memory.Can adapt its behaviours according to its

experience Every agent has its own goal.

Intelligent agent can evaluate different plans and choose the best one


What is ABM&S

3

ABMS has its direct historical roots in complex adaptive systems (CAS)Systems are built from the ground-up

Important results can emerge in systems that are completely described by simple rules that are based on only local information

Results that may develop can be extremely sensitive to the initial conditions.

Simple rules can be used to understand much of the complexity observed in the real world


Why ABM&S

4

I. Allow to simulate a complex system composed by many subsystem

organize system hierarchicallydecomposition of an agent in multi-agentssimplify interactions between entities when it's to hard to represent them with equations

II. Customize the target system as required by the case under studyIII. Allow to study of unexpected pertubations on the interconnected infrastructuresIV. Study the behaviour of an infrastructure for a certain input more than a equationsV. Allow to give a whole picture of the system behaviourVI. Allow to use external specific simulators, wrapping them with a agent


Independent or sequential simulation

E.g.:• Simulation of the effect of

fault in the power grid in [t1, t2].

• From the output i know that Roma-Est city’s area will experiment a blackout [t1’,t2’]

• I use such result to build a scenario for the simulation of the communication network behavior in [t1,t2] introducing a blackout starting at t1’ and ending at t2’

5

Sim i

Output processing

and analysis

Sim j

Output processing

and analysis

Sim k

Output processing

and analysis

IN_i OUT_i

OUT’_i

IN_j

IN_i,j

OUT_j

OUT_k

OUT’_j

IN_k

IN_i,k

IN’_k

OUT’_k


Interdependent or distributed simulation

E.g.: simulation of the transportation net., the power grid and the comm. net. in Roma in [t1,t2]

• At time t’>t1 the power grid experiment a failure.• Such failure propagates and have a direct effect at time t’+dt on a

node of the comm. net.• The failure of a comm. net. node has an impact on a not well known

simulated system that directly or indirectly use the CommNet, e.g. the transp. net.6

Local Ouputs e_i(t)

SIM a

RMI

SIM b

RMI

SIM d

RMI

SIM c

RMI

GRID and/or SOA communication

infrastructure relying on the internet

e_i(t)

e_i(t)

e_i(t)

Local input parameters

Collector

RMI

Database

Output processing

and visualization

o_c(t)

o_a(t) o_b(t)

o_d(t)

o_a(t), o_b(t) o_c(t) o_d(t)


Advantages & Disadvantages

Università di Roma "Tor Vergata" - CRESCO-SPIII7

Sequential:-/+ macroscopic

int. analysis- Do not emerge

unknown interdependencies

+ Does not require simulators re-engineering

Distributed:+ microscopic int.

analysis+ could emerge

unknown interdependency

- Requires simulators re-engineering or adaptation

Introduction to a custom approach with Repast and Omnet


We have used Repast as Toolkit for ABM&SWe have modeled both some Infrastructure

and simple users which use themWe have used OMNeT++ as framework

DES (discrete event simulation) to simulate Communication Network

We have developed a distributed approach with Repast and OMNeT to study an our defined simple scenario

Introduction to a custom approach with Repast and Omnet (cont.)


In Repast has been simulated interaction between different infrastructures.Every Infrastructure is an agent with its behaviour, memory and so on.The communication network is modelled using a specialized simulator:

OmnetThe agents which communicate using the Communication networks

use specific calls of the: CommunicationNetworkAgent V.Cardellini, E. Casalicchio, E. Galli. Agent-based Modelling of

Interdependencies in Critical Infrastructures through UML. In Proc. of Spring Simulation Multiconference 2007 (SpringSim07)

REPAST OMNET

InternetR1

R2

R3

R4R5IS4CEM

Wounded

CMN

HCC1Soccurer

Wounded

Soccurer

IS4CEM

HCC1

Implementation of model: Network


Based on two level:Interactions between infrastructures are controlled by

agents of RepastSimulation of communication network developped with

OMNet++ Developped an interface between Repast and

OMNet++The communication network is built in OMNet++

Setting of capacity of lynks between agentsSimulation of workload

The CommunicationNetwork Class of Repast control failure and can set new capacity for a link

Agents use CommunicationsNetwork’s method to send message to other agents on network

Implementation of model:Network (cont)


Example of sending of a message:Every agent that wants to send a message on network

comunicates its necessity to Communication Network Class

Communication Network prepares messages to send and uses the interface with OMNet++. Simulation is paused.

OMNet++ calculates routing and time for every new message and informs Communication Network, if any message is arrived at destination. The Communication Network Class determine if there is a failure in the communication (e.g. with a timeout).

Communication Network schedules reception of messages for every receiver-agents and the simulation restarts

Some screenshots: Repast & Omnet


Some screenshots: Graphs with Omnet


Some screenshots: GUI of Omnet


Conclusions


Study of the common scenarioCreate an interface for every Infrastructure

Simulator Study of interdependency between

different infrastructuresMapping every infrastructure to a

geographic locationUse of GIS or Google's API

Introduce a more complex fuzzy-set rules for every actors that we want to model

CRESCO SPIII.5 Project status 06-07-07

Documents

roma tor vergata cresco

roma tor vergatae

agent universit

romaest citys area

intelligent agent

blackout t1

system behaviour

complex system