John T. Lewis

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Logarithmic asymptotics are proved for the tail of the supremum of a stochastic process, under the assumption that the process satisfies a restricted large deviation principle on regularly varying scales. The formula for the rate of decay of the tail of the supremum, in terms of the underlying rate function, agrees with that stated by Duffield and O’Connell(More)
Fiducial markers are reference points used in the registration of image space(s) with physical (patient) space. As applied to interactive, image-guided surgery, the registration of image space with physical space allows the current location of a surgical tool to be indicated on a computer display of patient-specific preoperative images. This intrasurgical(More)
Our algorithm, called Mosquito 3 , allows sources to be ignorant of their statistics but ooers near-optimal utilisation of the network. Our approach is based on Large Deviation Theory : the large deviation rate-function (entropy) of bursty ATM traac can be estimated from measurements of traac activity. The entropy can be used to determine the bandwidth(More)
Quantum channels can be described via a unitary coupling of system and environment, followed by a trace over the environment state space. Taking the trace instead over the system state space produces a different mapping which we call the conjugate channel. We explore the properties of conjugate channels and describe several different methods of(More)
The thermodynamic entropy of an ATM traac stream is a useful tool for predicting cell-loss ratios and cell-delay. In 1] it was proposed that the entropy of a cell stream be estimated directly at a multiplexer; from this data, predictions can be made rapidly using algorithms which are simple enough to be executed on-they. Preliminary investigations using(More)
Registration of image space and physical space lies at the heart of any interactive, image-guided neurosurgery system. This paper, in conjunction with the previous companion paper [1], describes a localization technique that enables bone-implanted fiducial markers to be used for the registration of these spaces. The nature of these subcutaneous markers(More)
The thermodynamic entropy of an ATM tra c stream is a useful tool for predicting cell-loss ratios and cell-delay. In [1] it was proposed that the entropy of a cell stream be estimated directly at a multiplexor; from this data, predictions can be made rapidly using algorithms which are simple enough to be executed on-they. Preliminary investigations using(More)
In this paper, a technique based on the on-line estimation of the entropy of a traac stream is proposed for the prediction of bandwidth requirements. We report on the results of experiments designed to test the method. These experiments show that conservative estimates, within 3% of the true value as determined experimentally, can be achieved for Ethernet(More)