2,305 research outputs found
Identifying DNA motifs based on match and mismatch alignment information
The conventional way of identifying DNA motifs, solely based on match
alignment information, is susceptible to a high number of spurious sites. A
novel scoring system has been introduced by taking both match and mismatch
alignment information into account. The mismatch alignment information is
useful to remove spurious sites encountered in DNA motif searching. As an
example, a correct TATA box site in Homo sapiens H4/g gene has successfully
been identified based on match and mismatch alignment information
Fourier-based classification of protein secondary structures
The correct prediction of protein secondary structures is one of the key
issues in predicting the correct protein folded shape, which is used for
determining gene function. Existing methods make use of amino acids properties
as indices to classify protein secondary structures, but are faced with a
significant number of misclassifications. The paper presents a technique for
the classification of protein secondary structures based on protein
"signal-plotting" and the use of the Fourier technique for digital signal
processing. New indices are proposed to classify protein secondary structures
by analyzing hydrophobicity profiles. The approach is simple and
straightforward. Results show that the more types of protein secondary
structures can be classified by means of these newly-proposed indices
Achieving Covert Wireless Communications Using a Full-Duplex Receiver
Covert communications hide the transmission of a message from a watchful
adversary while ensuring a certain decoding performance at the receiver. In
this work, a wireless communication system under fading channels is considered
where covertness is achieved by using a full-duplex (FD) receiver. More
precisely, the receiver of covert information generates artificial noise with a
varying power causing uncertainty at the adversary, Willie, regarding the
statistics of the received signals. Given that Willie's optimal detector is a
threshold test on the received power, we derive a closed-form expression for
the optimal detection performance of Willie averaged over the fading channel
realizations. Furthermore, we provide guidelines for the optimal choice of
artificial noise power range, and the optimal transmission probability of
covert information to maximize the detection errors at Willie. Our analysis
shows that the transmission of artificial noise, although causes
self-interference, provides the opportunity of achieving covertness but its
transmit power levels need to be managed carefully. We also demonstrate that
the prior transmission probability of 0.5 is not always the best choice for
achieving the maximum possible covertness, when the covert transmission
probability and artificial noise power can be jointly optimized.Comment: 13 pages, 11 figures, Accepted for publication in IEEE Transactions
on Wireless Communication
Quantum spin Hall effect induced by electric field in silicene
We investigate the transport properties in a zigzag silicene nanoribbon in
the presence of an external electric field. The staggered sublattice potential
and two kinds of Rashba spin-orbit couplings can be induced by the external
electric field due to the buckled structure of the silicene. A bulk gap is
opened by the staggered potential and gapless edge states appear in the gap by
tuning the two kinds of Rashba spin-orbit couplings properly. Furthermore, the
gapless edge states are spin-filtered and are insensitive to the non-magnetic
disorder. These results prove that the quantum spin Hall effect can be induced
by an external electric field in silicene, which may have certain practical
significance in applications for future spintronics device.Comment: 4 pages, 5 figure
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