3,238 research outputs found
Ferromagnetism of an all-carbon composite composed of a carbon nanowire nside a single-walled carbon nanotube
Using the first-principles spin density functional approach, we have studied
magnetism of a new type of all-carbon nanomaterials, i.e., the carbon nanowires
inserted into the single-walled carbon nanotubes. It is found that if the 1D
carbon nanowire density is not too higher, the ferromagnetic ground state will
be more stable than the antiferromagnetic one, which is caused by weak coupling
between the 1D carbon nanowire and the single-walled carbon nanotube. Also,
both dimerization of the carbon nanowire and carbon vacancy on the tube-wall
are found to enhance the magnetic moment of the composite.Comment: 3 figure
Building user interest profiles from wikipedia clusters
Users of search systems are often reluctant to explicitly build profiles to indicate their search interests. Thus automatically building user profiles is an important research area for personalized search. One difficult component of doing this is accessing a knowledge system which provides broad coverage of user search interests. In this work, we describe a
method to build category id based user profiles from a user's
historical search data. Our approach makes significant use
of Wikipedia as an external knowledge resource
A Modified KZ Reduction Algorithm
The Korkine-Zolotareff (KZ) reduction has been used in communications and
cryptography. In this paper, we modify a very recent KZ reduction algorithm
proposed by Zhang et al., resulting in a new algorithm, which can be much
faster and more numerically reliable, especially when the basis matrix is ill
conditioned.Comment: has been accepted by IEEE ISIT 201
A Linearithmic Time Algorithm for a Shortest Vector Problem in Compute-and-Forward Design
We propose an algorithm with expected complexity of \bigO(n\log n)
arithmetic operations to solve a special shortest vector problem arising in
computer-and-forward design, where is the dimension of the channel vector.
This algorithm is more efficient than the best known algorithms with proved
complexity.Comment: It has been submitted to ISIT 201
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