Browsing by Author "Erciyes K."

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Citation - WoS: 13
Citation - Scopus: 12
Distributed Algorithms To Form Cluster Based Spanning Trees in Wireless Sensor Networks
(2008) Erciyes K.; Ozsoyeller D.; Dagdeviren O.
We propose two algorithms to form spanning trees in sensor networks. The first algorithm forms hierarchical clusters of spanning trees with a given root, the sink. All of the nodes in the sensor network are then classified iteratively as subroot, intermediate or leaf nodes. At the end of this phase, the local spanning trees are formed, each having a unique subroot (clusterhead) node. The communication and data aggregation towards the sink by an ordinary node then is accomplished by sending data to the local subroot which routes data towards the sink. A modified version of the first algorithm is also provided which ensures that the obtained tree is a breadth-first search tree where a node can modify its parent to yield shorter distances to the root. Once the sub-spanning trees in the clusters are formed, a communication architecture such as a ring can be formed among the subroots. This hybrid architecture which provides co-existing spanning trees within clusters yields the necessary foundation for a two-level communication protocol in a sensor network as well as providing a structure for a higher level abstraction such as the ? synchronizer where communication between the clusters is performed using the ring similar to an ? synchronizer and the intra cluster communication is accomplished using the sub-spanning trees as in the ? synchronizers. We discuss the model along with the algorithms, compare them and comment on their performances. © 2008 Springer-Verlag Berlin Heidelberg.
Citation - Scopus: 3
Distributed Weighted Node Shortest Path Routing for Wireless Sensor Networks
(2010) Yilmaz O.; Erciyes K.
Routing in Wireless Sensor Networks contains challenges, including limited energy constraints, network density, wireless channel errors. Different approaches exist in literature to overcome these challenges, such as data centric, location based and hierarchical routing. Most routing protocols in Wireless Sensor Networks are dealing with energy efficiency and network lifetime. In this paper, we present a shortest path routing algorithm based on Chandy-Misra's distributed shortest path algorithm regarding both node weight and edge weight. X percent of edge's weight and (100 - X) percent of node's weight form a total cost between neighbor and source node which is used in order to generate the shortest paths and construct a spanning tree. Variation of X percent, node weight and edge weight provide resilience for shaping needed paths and change the spanning tree's structure. When at least one node is close to critical energy level or a fault occurs, the routing algorithm is re-executed and new paths are generated. In order to obtain energy efficient paths, high network lifetime and finding out the overheads, we analyze the simulation results by assigning the battery level to node weight, communication cost to edge weight and %10, %30, %60 and %80 to X separately. © Springer-Verlag Berlin Heidelberg 2010.
A Hierarchical Architecture To Implement a ? Synchronizer in Wireless Sensor Networks
(2008) Ozsoyeller D.; Erciyes K.
A synchronizer provides synchronous execution of asynchronous algorithms in an asynchronous network. We provide an architecture for a ? synchronizer in a wireless sensor network. The sensor network is partitioned into clusters of connected sub-spanning trees by an algorithm described in[1] in the first phase. Once the sub-spanning trees in the clusters are formed, the Ring Formation Algorithm provides bands of rings among the clusterheads of the same levels. This structure provides the necessary architecture for the ? synchronizer where communication between the clusters is performed using the ring similar to a ? synchronizer and the intra cluster communication is accomplished using the sub-spanning tree as in ? synchronizers. We discuss the model along with the algorithms and show that this architecture provides scalable operation of a ? synchronizer in a sensor network of significant size. © 2008 IEEE.