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Cognitive radio (CR) technology is a promising emerging technology that enables a more efficient usage of already assigned spectrum. However, before CR networks can be deployed, new algorithms and protocols need to be developed. When forming an ad-hoc cognitive radio network (CRN), one of the fundamental tasks is to determine the neighbors of each node and(More)
Wormhole attack is a type of replay attack in wireless networks that has serious consequences and is hard to defend against. This is because the attacker does not need to modify packets or compromise wireless nodes. This paper introduces Wormeros, a new framework to detect wormhole attacks in wireless networks. The framework contains two phases namely(More)
Detecting termination of a distributed computation is a fundamental problem in distributed systems. We present two optimal algorithms for detecting termination of a non-diffusing distributed computation for an arbitrary topology. Both algorithms are optimal in terms of message complexity and detection latency. The first termination detection algorithm has(More)
Termination detection in distributed systems has been a popular problem of study. It involves determining whether a computation running on multiple nodes has ceased all its activities. A large number of termination detection algorithms have been proposed for static distributed systems in which the number of nodes present in the system is fixed and never(More)
The termination detection problem involves detecting whether an ongoing distributed computation has ceased all its activities. We investigate the termination detection problem in an asynchronous distributed system under crash-recovery model. It has been shown that the problem is impossible to solve under crash-recovery model in general. We identify two(More)
Message aggregation can be used to reduce the communication overhead in a network where many messages have the "same" content. However, it may make the network less secure because, once the aggregator is compromised, the data correctness cannot be ensured. In this paper, we present a new scheme THIS that allows a base station to accept the aggregated data(More)
Determining order relationship between events of a distributed computation is a fundamental problem in distributed systems which has applications in many areas including debugging, visualization, checkpointing and recovery. Fidge/Mattern's vector-clock mechanism captures the order relationship using a vector of size N in a system consisting of N processes.(More)
We introduce the notion of a slice of a distributed computation. A slice of a distributed computation with respect to a global predicate is a computation which captures those and only those consistent cuts of the original computation which satisfy the global predicate. We show that a slice exists for a global predicate iff the predicate is a regular(More)