Ph.D. Dissertation Defense

Relay Node Placement for
Federating Segmented Wireless Sensor Networks

Fatih Senel

2:00pm Tuesday, 10 July 2012, ITE 325b

Recent years have witnessed a growing interest in the applications of Wireless Sensor Networks (WSNs). Most notable among these applications are those operating in hostile environments space exploration, border protection, combat field reconnaissance, and search and rescue. Due to the harsh surroundings, WSNs may suffer from a large scale damage that causes many nodes to fail simultaneously and the network to get partitioned into multiple disjoint segments and its services become very limited. In such a case, restoring the network connectivity is very important in order to avoid negative effects on the applications. Linking disjoint segments may not be feasible through coordinated repositioning of some set of nodes as the scope of the damage is so wide that cannot be determined. One of the viable solutions for federating damaged WSNs is to deploy additional resources, i.e. relay nodes, to form inter-segment multi-hop paths.

In this dissertation, we tackle technical challenges related to the federation of segmented WSNs. We present a set of effective techniques that for repairing the damaged WSN using the least number of relay nodes (RNs) as well as maintaining some desirable topology features such as robustness against failures, network coverage and balanced traffic load. The correctness and time-complexity of all proposed approaches are analyzed and their performance is validated through extensive simulation experiments.

Committee: Drs. Mohamed Younis (Chair), Charles Nicholas, Samuel Lomonaco, Tim Oates, Kemal Akkaya and Waleed Youssef

1 John 4:9-17 (NLT)

9 God showed how much he loved us by sending his one and only Son into the world so that we might have eternal life through him.
10 This is real love—not that we loved God, but that he loved us and sent his Son as a sacrifice to take away our sins.
11 Dear friends, since God loved us that much, we surely ought to love each other. 12 No one has ever seen God. But if we love each other, God lives in us, and his love is brought to full expression in us.
13 And God has given us his Spirit as proof that we live in him and he in us. 14 Furthermore, we have seen with our own eyes and now testify that the Father sent his Son to be the Savior of the world. 15 All who confess that Jesus is the Son of God have God living in them, and they live in God. 16 We know how much God loves us, and we have put our trust in his love.
God is love, and all who live in love live in God, and God lives in them. 17 And as we live in God, our love grows more perfect. So we will not be afraid on the day of judgment, but we can face him with confidence because we live like Jesus here in this world.

Reflection:

We are called to live with the roots of our lives planted deep in the love of Christ for us. Being loved by Christ and knowing His love is the ground for becoming loving, and the root we put into that ground is the trust we put in His love. By His Spirit, we have come to know His love, and as we believe more and more in His love for us, love for one another and for others will grow and deepen.

Response:

May we consider the depth of Christ’s love for us – the cost, how little we deserve it, and all that we have received from His love. Let’s ask God to transform our hearts even more to receive and believe in this love – this love He demonstrated by sending His Son as a sacrifice to take away our sins. Let’s also ask to be rooted in His love and so become more like Him.