Tesi di laurea vecchio ordinamento
Collaborative Resource Allocation in Wireless Sensor Networks.
Corso di studi
Relatore Ancilotti, Paolo
- Non-Linear Convex Problem.
- Sensor Networks
- Wireless Sensor Netwoks
- Collaborative Resource Allocation
Data inizio appello
<br><br><br><P ALIGN=CENTER><FONT SIZE=5><B>Collaborative Resource Allocation in<br>Wireless Sensor Networks</B></FONT></P><br><P ALIGN=CENTER>&nbsp;</P><br><P>The new millennium heralds the convergence of communication,<br>computing and intelligent control of the physical environment. The<br>rapid advancement of computing and wireless technologies will enable<br>us to employ cooperative real-time nodes in hostile environments in<br>order to accomplish different tasks ranging from space monitoring and<br>surveillance, to environmental protection without human intervention.<br>Under this challenging vision, there will be an extensive deployment<br>of highly dynamic and physically constrained real-time nodes<br>connected together. <br></P><br><P>Let us consider the following examples:</P><br><UL TYPE=DISC><br> <LI><P>Cooperative mobile robots, equipped with visual sensing, <br><br>used<br> in hostile/dangerous environments to clean up highly polluted <br><br>spots<br> or to remove mines or to defuse bombs. <br> </P><br> <LI><P>Cooperative real-time nodes, equipped with acoustic and<br> visual sensing, used for surveillance in wide open spaces. <br> </P><br> <LI><P>Network of multifunction phase array radars (this is an<br> example of real-time systems with physical constraints) used for<br> air-traffic control or for military purpose such as<br> detecting/tracking hostile targets. <br> </P><br></UL><br><P>&nbsp;</P><br><P>It&rsquo;s worth noting that all the applications mentioned above<br>are characterized by a high degree of fluctuation in terms of<br>computational and/or networking resource requirements. However, the<br>causes of such a dynamic behavior are different in fact; for example,<br>visual tracking is the main cause of highly variable workload in<br>cooperative robots equipped with visual sensing, while, on the other<br>hand, variable number of tracked targets and state dependent tasks<br>cause highly dynamic workload in radar systems.</P><br><P>&nbsp;</P><br><P>When several real-time nodes are connected together, the need for<br>collaboration in a timely manner creates the following challenging<br>problems:</P><br><P>&nbsp;</P><br><UL TYPE=DISC><br> <LI><P>Handling highly dynamic workloads among collaborative <br><br>nodes. <br> </P><br> <LI><P>Providing real-times wireless communication.&nbsp;</P><br></UL><br><P>&nbsp;</P><br><P>Under the three major problems above identified, this thesis will<br>focus primarily on issues like collaborative scheduling and<br>prioritized medium access protocols.</P><br><P>Specifically, the guidelines of this work are the followings:</P><br><UL TYPE=DISC><br> <LI><P><B>Collaborative Scheduling:</B> tasks running on <br><br>different<br> nodes can be tightly coupled in a system where several real-time<br> nodes cooperate. The goal is to develop distributed rate <br><br>adaptation<br> and collaborative resource reclaiming techniques aimed at <br><br>mitigating<br> the effects of highly dynamic workloads in distributed real-time<br> system composed of collaborative nodes. It is worth noting that <br><br>the<br> degradation of performance of one task might affect the <br><br>performance<br> of other tasks running on different nodes (<B>bottleneck</B> <br><br>task<br> problem due to local rate adaptation), or locally reclaimed<br> resources could increase a task rate without improving the <br><br>overall<br> system performance. <br> </P><br> <LI><P><B>Prioritized Medium Access with rate adaptive <br><br>messages</B>:<br> traditional medium access control (MAC) are not suitable to <br><br>build<br> wireless sensor networks of collaborative real-time nodes <br><br>because<br> messages exchanged inside the network are mainly periodic and <br><br>need<br> guaranteed bounded delay. As a consequence, we will try to <br><br>address<br> the following medium access issues: <br> </P><br></UL><br><UL TYPE=DISC><br> <UL><br> <UL><br> <LI><P>Prioritizing the medium access to provide <br><br>messages with<br> bounded delay, and <br> </P><br> <LI><P>Providing rate adaptive messages in order <br><br>to achieve the<br> concept of distributed rate adaptation. <br> </P><br> </UL><br> </UL><br></UL><br><P><BR><BR><br></P>