jourpubs.bib
@article{rozell.06d,
author = {Rozell, C.J. and Johnson, D.H.},
title = {Resource allocation and control in redundant wireless sensor and actuator networks},
note = {In preparation.}
}
@article{rozell.06c,
author = {Rozell, C.J. and Johnson, D.H and Baraniuk, R.G. and Olshausen, B.A.},
title = {Sparse coding via thresholding and local competition in neural circuits},
journal = {Neural Computation},
year = {2008},
volume = {20},
number = {10},
pages = {2526--2563},
month = {October},
abstract = {While evidence indicates that neural systems may be
employing sparse approximations to represent sensed
stimuli, the mechanisms underlying this ability are
not understood. We describe a local ly competitive
algorithm (LCA) that solves a collection of sparse
coding principles minimizing a weighted combination
of mean-squared error (MSE) and a coefficient cost
function. LCAs are designed to be implemented in a
dynamical system composed of many neuron-like
elements operating in parallel. These algorithms use
thresholding functions to induce local (usually
one-way) inhibitory competitions between nodes to
produce sparse representations. LCAs produce
coefficients with sparsity levels comparable to the
most popular centralized sparse coding algorithms
while being readily suited for neural
implementation. Addi- tionally, LCA coefficients for
video sequences demonstrate inertial properties that
are both qualitatively and quantitatively more
regular (i.e., smoother and more predictable) than
the coefficients produced by greedy algorithms. },
url = {http://www.ece.rice.edu/~crozell/pubs/rozellNeuralComp2008.pdf}
}
@article{bishnoi.06,
author = {Bishnoi,S.W. and Rozell,C.J. and Levin,C.S. and Gheith,M.K. and Johnson,B.R. and Johnson,D.H. and Halas, N.J},
title = {All-optical nanoscale {pH} meter},
journal = {Nano Letters},
year = {2006},
volume = {6},
number = {8},
pages = {1687--1692},
month = {August},
abstract = {We show that an Au nanoshell with a pH sensitive
molecular adsorbate functions as a standalone, all-optical nanoscale
pH meter that monitors its local environment through the
pH-dependent surface enhanced Raman scattering (SERS) spectra of the
adsorbate molecules. Moreover, we also show how the performance of
such a functional nanodevice can be quantitatively assessed. The
complex spectral output is reduced to a simple device characteristic
by application of a locally linear manifold approximation
algorithm. The average accuracy of the nano-``meter'' was found to
be ± 0.10 pH units across its operating range.}
}
@article{rozell.05,
author = {Rozell, C.J. and Johnson, D.H.},
title = {Analyzing the robustness of redundant population codes in sensory and feature extraction systems},
journal = {Neurocomputing},
year = {2006},
volume = {69},
number = {10--12},
pages = {1215--1218},
month = {June},
note = {Also appears in {\it Proceedings of the Computational Neuroscience Meeting (CNS)}, Madison, WI, July 2005.},
abstract = {Sensory systems often use groups of redundant neurons to represent
stimulus information both during transduction and population coding of
features. This redundancy makes the system more robust to corruption
in the representation. We approximate neural coding as a projection of
the stimulus onto a set of vectors, with the result encoded by spike
trains. We use the formalism of frame theory to quantify the inherent
noise reduction properties of such population codes. Additionally,
computing features from the stimulus signal can also be thought of as
projecting the coefficients of a sensory representation onto another
set of vectors specific to the feature of interest. The conditions
under which a combination of different features form a complete
representation for the stimulus signal can be found through a recent
extension to frame theory called ``frames of subspaces.'' We extend
the frame of subspaces theory to quantify the noise reduction
properties of a collection of redundant feature spaces.},
url = {http://www.ece.rice.edu/~crozell/pubs/rozellCNS2005.pdf}
}
@article{rozell.04c,
author = {Rozell, C.J. and Johnson, D.H.},
title = {Examining methods for estimating mutual information in spiking neural systems},
journal = {Neurocomputing},
year = {2005},
volume = {65--66C},
pages = {429--434},
month = {June},
note = {Also appears in {\it Proceedings of the Computational Neuroscience Meeting (CNS)}, Baltimore, MD, July 2004.},
abstract = {Mutual information enjoys wide use in the computational neuroscience community for
analyzing spiking neural systems. Its direct calculation is difficult
because estimating the joint stimulus-response distribution requires a
prohibitive amount of data. Consequently, several techniques have
appeared for bounding mutual information that rely on less data. We
examine two upper bound techniques and find that they are either
unreliable or introduce strong assumptions about the neural code. We also
examine two lower bounds, showing that they can be very loose and
possibly bear little relation to the mutual information's actual value.},
url = {http://www.ece.rice.edu/~crozell/pubs/rozellCNS2004.pdf}
}
@article{rozell.04,
author = {Rozell, C.J. and Johnson, D.H. and Glantz, R.M.},
title = {Measuring information transfer in crayfish sustaining fiber spike generators},
journal = {Biological Cybernetics},
year = {2004},
volume = {90},
number = {2},
pages = {89--97},
month = {February},
webnote = {Copyright held by Springer-Verlag. The original
publication is available at springerlink.com. DOI:10.1007/s00422-003-0458-y},
abstract = {We present a method based
on information-theoretic distances for measuring the information
transfer efficiency of voltage to impulse encoders. In response to light
pulses, we simultaneously recorded the EPSP and spiking output of
crayfish sustaining fibers. To measure the distance between analog
EPSP responses, we developed a membrane noise model that accurately
captures stimulus-induced nonstationarities. By comparing the EPSP
and spike responses, we found encoding efficiencies on the order
of $10^{-4}$, with interesting dynamics occurring during initial
transients. A simple analog to point-process converter predicted the small
information transfer efficiencies and dynamic properties we measured.},
url = {http://www.ece.rice.edu/~crozell/pubs/rozellBC2004.pdf}
}
@article{rozell.03,
author = {Rozell, C.J. and Johnson, D.H. and Glantz, R.M.},
title = {Information processing during transient responses in the crayfish visual system},
journal = {Neurocomputing},
year = {2003},
volume = {52--54},
pages = {53--58},
month = {June},
note = {Also appears in {\it Proceedings of the Computational Neuroscience Meeting (CNS)}, Chicago, IL, July 2002.},
abstract = {We analyzed sustaining fiber
responses in the crayfish visual system to light pulses using information
processing techniques. The light pulse stimuli elicited a transient and
a steady-state component in the EPSP input and in the firing rate
of the spike train output. The overall information transfer of the
system was very low ($10^{-4}$), with a sharp increase during the
transient portion of the response followed by a steady decrease. The
information transfer dynamics are consistent with a simple spike
generator model that depends explicitly on stimulus changes. The
present analysis also corroborates the observed light reflex behavior.},
url = {http://www.ece.rice.edu/~crozell/pubs/rozellCNS2002.pdf}
}