John MacLaren Walsh

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Channel shortening is often employed as a means of mitigating intersymbol and intercarrier interference (ISI and ICI) in systems using multicarrier modulation. The Multicarrier Equalization by Restoration of RedundancY (MERRY) algorithm has previously been shown to blindly and adaptively shorten a channel to the length of the guard interval in a(More)
The Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) instruments were evaluated for the identification of nonfermenting gram-negative bacilli (NFGNB) by a blinded comparison to conventional biochemical or molecular methods. Two hundred NFGNB that were recovered from cultures from(More)
Resource allocation and link adaptation in long term evolution (LTE) and LTE Advanced are discussed with a focus on the location and formatting of the pertinent reference and control signals, as well as the decisions they enable. In particular, after reviewing the units for resource allocation and the time frequency resource grid, the enabled resource(More)
The turbo decoder was not originally introduced as a solution to an optimization problem, which has impeded attempts to explain its excellent performance. Here it is shown, that the turbo decoder is an iterative method seeking a solution to an intuitively pleasing constrained optimization problem. In particular, the turbo decoder seeks the(More)
Rapid identification of microorganisms causing bloodstream infections directly from a positive blood culture would decrease the time to directed antimicrobial therapy and greatly improve patient care. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) is a fast and reliable method for identifying microorganisms(More)
Many previous attempts at analyzing the convergence behavior of turbo and iterative decoding, such as EXIT style analysis [1] and density evolution [2], ultimately appeal to results which become valid only when the block length grows rather large, while still other attempts, such as connections to factor graphs [3] and belief propagation [4], have been(More)
Via multiterminal information theory, we present fundamental rate delay tradeoffs that delay mitigating codes must have when utilized over multipath routed and network coded networks. We formulate plotting the rate delay tradeoff as a calculus problem on a capacity region of a related abstracted broadcast channel. This calculus problem simplifies to an(More)
The turbo decoder was not originally introduced as a solution to an optimization problem. This has made explaining just why the turbo decoder performs as well as it does very difficult. Many authors have attempted to explain both the performance and convergence of the decoder, with varied success. In this document we show that the turbo decoder admits an(More)
Expectation propagation defines a family of algorithms for approximate Bayesian statistical inference which generalize belief propagation on factor graphs with loops. As is the case for belief propagation in loopy factor graphs, it is not well understood why the stationary points of expectation propagation can yield good estimates. In this paper, given a(More)