2,333 research outputs found
Dissecting the Biological Motherboard (Systems Biology and Beyond)
Genome-scale molecular networks, including gene pathways, gene regulatory networks and protein interactions, are central to the investigation of the nascent disciplines of systems biology and bio-complexity. Dissecting these genome-scale molecular networks in its all-possible manifestations is paramount in our quest for a genotype-input phenotype-output application which will also take environment-genome interactions into account.

Machine learning approaches are now increasingly being used for reverse engineering such networks. Our work stresses the importance of a system approach in biological research and how artificial neural networks are at the forefront of Artificial Intelligence techniques that are increasingly being used to construct as well as dissect molecular networks, the building blocks of the living system.

Our paper will show the application of artificial neural networks to reverse engineer a temporal gene pathway 
In this paper we will also explore the pruning of nodes of these artificial neural networks to simulate gene silencing and thus generate novel biological insight into these molecular networks (The Biological Motherboard).

The research described is novel, in that this may be the first time that the application of neural networks to temporal gene expression data is described. It will be shown that a trained artificial neural network, with pruning, can also be described as a gene network with minimal re-interpretation, where the weights on links between nodes reflect the probability of one gene affecting another gene in time
Multilevel Coding Schemes for Compute-and-Forward with Flexible Decoding
We consider the design of coding schemes for the wireless two-way relaying
channel when there is no channel state information at the transmitter. In the
spirit of the compute and forward paradigm, we present a multilevel coding
scheme that permits computation (or, decoding) of a class of functions at the
relay. The function to be computed (or, decoded) is then chosen depending on
the channel realization. We define such a class of functions which can be
decoded at the relay using the proposed coding scheme and derive rates that are
universally achievable over a set of channel gains when this class of functions
is used at the relay. We develop our framework with general modulation formats
in mind, but numerical results are presented for the case where each node
transmits using the QPSK constellation. Numerical results with QPSK show that
the flexibility afforded by our proposed scheme results in substantially higher
rates than those achievable by always using a fixed function or by adapting the
function at the relay but coding over GF(4).Comment: This paper was submitted to IEEE Transactions on Information Theory
in July 2011. A shorter version also appeared in the proceedings of the
International Symposium on Information Theory in August 2011 without the
proof of the main theore
Joint Compute and Forward for the Two Way Relay Channel with Spatially Coupled LDPC Codes
We consider the design and analysis of coding schemes for the binary input
two way relay channel with erasure noise. We are particularly interested in
reliable physical layer network coding in which the relay performs perfect
error correction prior to forwarding messages. The best known achievable rates
for this problem can be achieved through either decode and forward or compute
and forward relaying. We consider a decoding paradigm called joint compute and
forward which we numerically show can achieve the best of these rates with a
single encoder and decoder. This is accomplished by deriving the exact
performance of a message passing decoder based on joint compute and forward for
spatially coupled LDPC ensembles.Comment: This paper was submitted to IEEE Global Communications Conference
201
Iterative Soft Input Soft Output Decoding of Reed-Solomon Codes by Adapting the Parity Check Matrix
An iterative algorithm is presented for soft-input-soft-output (SISO)
decoding of Reed-Solomon (RS) codes. The proposed iterative algorithm uses the
sum product algorithm (SPA) in conjunction with a binary parity check matrix of
the RS code. The novelty is in reducing a submatrix of the binary parity check
matrix that corresponds to less reliable bits to a sparse nature before the SPA
is applied at each iteration. The proposed algorithm can be geometrically
interpreted as a two-stage gradient descent with an adaptive potential
function. This adaptive procedure is crucial to the convergence behavior of the
gradient descent algorithm and, therefore, significantly improves the
performance. Simulation results show that the proposed decoding algorithm and
its variations provide significant gain over hard decision decoding (HDD) and
compare favorably with other popular soft decision decoding methods.Comment: 10 pages, 10 figures, final version accepted by IEEE Trans. on
Information Theor
A Decision Feedback Based Scheme for Slepian-Wolf Coding of sources with Hidden Markov Correlation
We consider the problem of compression of two memoryless binary sources, the
correlation between which is defined by a Hidden Markov Model (HMM). We propose
a Decision Feedback (DF) based scheme which when used with low density parity
check codes results in compression close to the Slepian Wolf limits.Comment: Submitted to IEEE Comm. Letter
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