• Sensor Networks
• Non-Linear Convex Problem.
• Real-Time
• Wireless
• Collaborative Resource Allocation
• Wireless Sensor Netwoks

<P ALIGN=CENTER><FONT SIZE=5><B>Collaborative Resource Allocation in
Wireless Sensor Networks</B></FONT></P>
<P ALIGN=CENTER>&nbsp;</P>
<P>The new millennium heralds the convergence of communication,
computing and intelligent control of the physical environment. The
rapid advancement of computing and wireless technologies will enable
us to employ cooperative real-time nodes in hostile environments in
order to accomplish different tasks ranging from space monitoring and
surveillance, to environmental protection without human intervention.
Under this challenging vision, there will be an extensive deployment
of highly dynamic and physically constrained real-time nodes
connected together.
</P>
<P>Let us consider the following examples:</P>
<UL TYPE=DISC>
<LI><P>Cooperative mobile robots, equipped with visual sensing,

used
in hostile/dangerous environments to clean up highly polluted

spots
or to remove mines or to defuse bombs.
</P>
<LI><P>Cooperative real-time nodes, equipped with acoustic and
visual sensing, used for surveillance in wide open spaces.
</P>
<LI><P>Network of multifunction phase array radars (this is an
example of real-time systems with physical constraints) used for
air-traffic control or for military purpose such as
detecting/tracking hostile targets.
</P>
</UL>
<P>&nbsp;</P>
<P>It&rsquo;s worth noting that all the applications mentioned above
are characterized by a high degree of fluctuation in terms of
computational and/or networking resource requirements. However, the
causes of such a dynamic behavior are different in fact; for example,
visual tracking is the main cause of highly variable workload in
cooperative robots equipped with visual sensing, while, on the other
hand, variable number of tracked targets and state dependent tasks
cause highly dynamic workload in radar systems.</P>
<P>&nbsp;</P>
<P>When several real-time nodes are connected together, the need for
collaboration in a timely manner creates the following challenging
problems:</P>
<P>&nbsp;</P>
<UL TYPE=DISC>
<LI><P>Handling highly dynamic workloads among collaborative

nodes.
</P>
<LI><P>Providing real-times wireless communication.&nbsp;</P>
</UL>
<P>&nbsp;</P>
<P>Under the three major problems above identified, this thesis will
focus primarily on issues like collaborative scheduling and
prioritized medium access protocols.</P>
<P>Specifically, the guidelines of this work are the followings:</P>
<UL TYPE=DISC>
<LI><P><B>Collaborative Scheduling:</B> tasks running on

different
nodes can be tightly coupled in a system where several real-time
nodes cooperate. The goal is to develop distributed rate

adaptation
and collaborative resource reclaiming techniques aimed at

mitigating
the effects of highly dynamic workloads in distributed real-time
system composed of collaborative nodes. It is worth noting that

the
degradation of performance of one task might affect the

performance
of other tasks running on different nodes (<B>bottleneck</B>

task
problem due to local rate adaptation), or locally reclaimed
resources could increase a task rate without improving the

overall
system performance.
</P>
<LI><P><B>Prioritized Medium Access with rate adaptive

messages</B>:
traditional medium access control (MAC) are not suitable to

build
wireless sensor networks of collaborative real-time nodes

because
messages exchanged inside the network are mainly periodic and

need
guaranteed bounded delay. As a consequence, we will try to

address
the following medium access issues:
</P>
</UL>
<UL TYPE=DISC>
<UL>
<UL>
<LI><P>Prioritizing the medium access to provide

messages with
bounded delay, and
</P>
<LI><P>Providing rate adaptive messages in order

to achieve the
concept of distributed rate adaptation.
</P>
</UL>
</UL>
</UL>
<P><BR><BR>
</P>