James A. Malcolm

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Researchers have used extensive simulation and experimental studies to understand TCP performance in adhoc wireless networks. In contrast, the objective of this paper is to theoretically analyze TCP performance in this environment. By examining the case of running one TCP session over a string topology, a system model for analyzing TCP performance in adhoc(More)
Over the past few years, several local search algorithms have been proposed for various problems related to multicast routing in the off-line mode. We describe a population-based search algorithm for cost minimisation of multicast routing. The algorithm utilises the partially mixed crossover operation (PMX) under the elitist model: for each element of the(More)
The unique characteristics of a mobile ad hoc network (MANET), such as dynamic topology, shared wireless medium and open peer-to-peer network architecture, pose various security challenges. This paper compares three routing protocols, DSDV, DSR, and AODV under security attack where two types of node misbehaviour have been investigated. Network performance(More)
Ferret is a fast and effective tool for detecting similarities in a group of files. Applying it to the PAN’09 corpus required modifications to meet the requirements of the competition, mainly to deal with the very large number of files, the large size of some of them, and to automate some of the decisions that would normally be made by a human operator.(More)
Public key cryptography is often used to verify the integrity of a piece of data, or more generally to ensure that operations which modify the data have been requested and carried out by principals who are authorized to do so. This requires keys to be bound to principals in an unforgeably veriiable manner. Cryptographic bit patterns such as electronic key(More)
Wireless sensor networks (WSNs) have attracted considerable interest in the research community, because of their wide range of applications. However, due to the distributed nature of WSNs and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. Resource constraints(More)
Text-based approaches to the analysis of software evolution are attractive because of the fine-grained, token-level comparisons they can generate. The use of such approaches has, however, been constrained by the lack of an efficient implementation. In this paper we demonstrate the ability of Ferret, which uses n-grams of 3 tokens, to characterise the(More)
If we are to use electronic plagiarism detectors on student work, it would be interesting to know how much similarity should be expected in independently written documents on a similar topic. If our measure is coarse, the answer should be zero, but a finer grained analysis (such as would be needed to detect inadequate paraphrasing) is likely to detect some(More)