Bruce Christianson

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Background: The NASA Metrics Data Program data sets have been heavily used in software defect prediction experiments. Aim: To demonstrate and explain why these data sets require significant pre-processing in order to be suitable for defect prediction. Method: A meticulously documented data cleansing process involving all 13 of the original NASA data sets.(More)
Background: The NASA metrics data program (MDP) data sets have been heavily used in software defect prediction research. Aim: To highlight the data quality issues present in these data sets, and the problems that can arise when they are used in a binary classification context. Method: A thorough exploration of all 13 original NASA data sets, followed by(More)
The automated detection of defective modules within software systems could lead to reduced development costs and more reliable software. In this work the static code metrics for a collection of modules contained within eleven NASA data sets are used with a Support Vector Machine classifier. A rigorous sequence of pre-processing steps were applied to the(More)
A number of security systems, from Chip-and-PIN payment cards to contactless subway and train tokens, as well as secure localization systems, are vulnerable to relay attacks. Encrypting the communication between the honest endpoints does not protect against such attacks. The main solution that has been o ered to date is distance bounding, in which a tightly(More)
We apply reverse accumulation to obtain automatic gradients and error estimates of func tions which include in their computation a convergent iteration of the form y y u where y and u are vectors We suggest an implementation approach which allows this to be done by a fairly routine extension of existing reverse accumulation code We show how to re use the(More)
Let n be the number of independent variables of a function f and let W S respectively be the time and space bounds for the joint evaluation of ff rfg using automatic di eren tiation with reverse accumulation In this note we examine an extension of the technique of reverse accumulation which allows the automatic extraction of the Hessian of f The method(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)
Sometimes two parties who share a weak secret k such as a password wish to share a strong secret s such as a session key without revealing information about k to an active attacker. We assume that both parties can generate strong random numbers and forget secrets, and present three protocols for secure strong secret sharing, based on RSA, Diffie-Hellman,(More)
Computer n the spring of 1989, students at the University of Cambridge successfully penetrated the Computer Laboratory system. The attack on I computers used as public area terminals was intricate and involved physically dismantling and replacing components with new firmware that recorded user passwords for later replay.’ The laboratory responded by(More)