Evaluating a Bio-Inspired Approach for the Design of a Grid Information System - Advancing Artificial Intelligence Through Biological Process Applications - page 302

Figure 5. SO-Grid portal: Overall architecture

flooding or random walks techniques) is simple
to implement but has limited performance and
can cause an excessive network load, whereas
a pure informed approach generally requires a
very structured resource organization which is
impractical in a large, heterogeneous and dy-
namic Grid.

back-end, which includes the So-Grid controller, a
database and a file repository and (3) the So-Grid
event-based simulator.
In the following, the portal components will be
briefly described, in a right to left order, starting
from the simulator.

The SO-Grid Simulator

THE SO-GRID PORTAL The performances of the ARMAP and ARDIP

protocols have been evaluated through an event-
based simulator written in Java. Simulation objects
are used to emulate Grid hosts and bio-inspired
agents. Each object reacts to external events ac-
cording to a finite state automaton and responds
by performing specific operations and/or by
generating new messages/events to be delivered
to other objects.
For example, a peer visited by an agent gives
it information about the descriptors that this peer
maintains; afterwards the agent uses the prob-
ability functions define in formulas (1) and (2) to
decide whether or not to pick descriptors from or
drop descriptors into the peer. Finally, the agent
sets the simulation time in which it will perform
its next movement on the Grid and creates a related
event that will be delivered at the specified time
to the peer to which the agent will move. Events
are ordered in a general queue by a simulation

The ICAR research institute of the Italian CNR
recently developed the So-Grid (Self Organizing
Grid) Portal, available at the URL http://so-grid.
icar.cnr.it , in order to allow remote users to ex-
perience and evaluate the bio-inspired protocols
described in this chapter. The portal, designed
according to the Java J2EE technology and built
upon the JBoss application server, provide users
with a Web interface through which it is pos-
sible to run a remote simulation, after setting its
parameters, graphically monitor the simulation
execution at run time and compare the results of
several simulations in order to perform “parameter
sweep” analysis.
The overall architecture of the portal is de-
picted in Figure 5. The portal is composed of
three main tiers: (1) the portal front-end, which
gives access to the Web interface; (2) the portal