11,929 research outputs found
Knowledge-based Query Expansion in Real-Time Microblog Search
Since the length of microblog texts, such as tweets, is strictly limited to
140 characters, traditional Information Retrieval techniques suffer from the
vocabulary mismatch problem severely and cannot yield good performance in the
context of microblogosphere. To address this critical challenge, in this paper,
we propose a new language modeling approach for microblog retrieval by
inferring various types of context information. In particular, we expand the
query using knowledge terms derived from Freebase so that the expanded one can
better reflect users' search intent. Besides, in order to further satisfy
users' real-time information need, we incorporate temporal evidences into the
expansion method, which can boost recent tweets in the retrieval results with
respect to a given topic. Experimental results on two official TREC Twitter
corpora demonstrate the significant superiority of our approach over baseline
methods.Comment: 9 pages, 9 figure
Generalization Bounds for Representative Domain Adaptation
In this paper, we propose a novel framework to analyze the theoretical
properties of the learning process for a representative type of domain
adaptation, which combines data from multiple sources and one target (or
briefly called representative domain adaptation). In particular, we use the
integral probability metric to measure the difference between the distributions
of two domains and meanwhile compare it with the H-divergence and the
discrepancy distance. We develop the Hoeffding-type, the Bennett-type and the
McDiarmid-type deviation inequalities for multiple domains respectively, and
then present the symmetrization inequality for representative domain
adaptation. Next, we use the derived inequalities to obtain the Hoeffding-type
and the Bennett-type generalization bounds respectively, both of which are
based on the uniform entropy number. Moreover, we present the generalization
bounds based on the Rademacher complexity. Finally, we analyze the asymptotic
convergence and the rate of convergence of the learning process for
representative domain adaptation. We discuss the factors that affect the
asymptotic behavior of the learning process and the numerical experiments
support our theoretical findings as well. Meanwhile, we give a comparison with
the existing results of domain adaptation and the classical results under the
same-distribution assumption.Comment: arXiv admin note: substantial text overlap with arXiv:1304.157
NRQCD Predictions of D-Wave Quarkonia Decay into Light Hadrons at Order
In this paper, in the framework of NRQCD we study the light hadron (LH)
decays of the spin-triplet (S=1) D-wave heavy quarkonia. The short distance
coefficients of all Fock states in the quarkonia including
D-wave color-singlet, P-wave color-octet and S-wave color-singlet and
color-octet are calculated perturbatively at order. The operator
evolution equations of the four-fermion operators are also derived and are used
to estimate the numerical values of the long distance matrix elements. We find
that for the system, the LH decay widths of predicted
by NRQCD is about times larger than the phenomenological potential
model results, while for the system the two theoretical estimations
of are in coincidence with each other. Our
predictions for LH decay widths are MeV for J=1,2,3; and for ,
KeV for J=1,2,3.Comment: 12 figures, references added, published version in PR
Recovering Multiplexing Loss Through Successive Relaying Using Repetition Coding
In this paper, a transmission protocol is studied for a two relay wireless
network in which simple repetition coding is applied at the relays.
Information-theoretic achievable rates for this transmission scheme are given,
and a space-time V-BLAST signalling and detection method that can approach them
is developed. It is shown through the diversity multiplexing tradeoff analysis
that this transmission scheme can recover the multiplexing loss of the
half-duplex relay network, while retaining some diversity gain. This scheme is
also compared with conventional transmission protocols that exploit only the
diversity of the network at the cost of a multiplexing loss. It is shown that
the new transmission protocol offers significant performance advantages over
conventional protocols, especially when the interference between the two relays
is sufficiently strong.Comment: To appear in the IEEE Transactions on Wireless Communication
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