336,858 research outputs found
Theoretical Limits on Agegraphic Quintessence from Weak Gravity Conjecture
In this paper, we investigate the possible theoretical constraint on the
parameter of the agegraphic quintessence model by considering the
requirement of the weak gravity conjecture that the variation of the
quintessence scalar field should be less than the Planck mass
. We obtain the theoretical upper bound that is
inconsistent with the current observational constraint result
(95.4% CL). The possible implications of the tension between observational and
theoretical constraint results are discussed.Comment: 14 pages, 3 figure
FiBiNET: Combining Feature Importance and Bilinear feature Interaction for Click-Through Rate Prediction
Advertising and feed ranking are essential to many Internet companies such as
Facebook and Sina Weibo. Among many real-world advertising and feed ranking
systems, click through rate (CTR) prediction plays a central role. There are
many proposed models in this field such as logistic regression, tree based
models, factorization machine based models and deep learning based CTR models.
However, many current works calculate the feature interactions in a simple way
such as Hadamard product and inner product and they care less about the
importance of features. In this paper, a new model named FiBiNET as an
abbreviation for Feature Importance and Bilinear feature Interaction NETwork is
proposed to dynamically learn the feature importance and fine-grained feature
interactions. On the one hand, the FiBiNET can dynamically learn the importance
of features via the Squeeze-Excitation network (SENET) mechanism; on the other
hand, it is able to effectively learn the feature interactions via bilinear
function. We conduct extensive experiments on two real-world datasets and show
that our shallow model outperforms other shallow models such as factorization
machine(FM) and field-aware factorization machine(FFM). In order to improve
performance further, we combine a classical deep neural network(DNN) component
with the shallow model to be a deep model. The deep FiBiNET consistently
outperforms the other state-of-the-art deep models such as DeepFM and extreme
deep factorization machine(XdeepFM).Comment: 8 pages,5 figure
Cooperative Precoding with Limited Feedback for MIMO Interference Channels
Multi-antenna precoding effectively mitigates the interference in wireless
networks. However, the resultant performance gains can be significantly
compromised in practice if the precoder design fails to account for the
inaccuracy in the channel state information (CSI) feedback. This paper
addresses this issue by considering finite-rate CSI feedback from receivers to
their interfering transmitters in the two-user multiple-input-multiple-output
(MIMO) interference channel, called cooperative feedback, and proposing a
systematic method for designing transceivers comprising linear precoders and
equalizers. Specifically, each precoder/equalizer is decomposed into inner and
outer components for nulling the cross-link interference and achieving array
gain, respectively. The inner precoders/equalizers are further optimized to
suppress the residual interference resulting from finite-rate cooperative
feedback. Further- more, the residual interference is regulated by additional
scalar cooperative feedback signals that are designed to control transmission
power using different criteria including fixed interference margin and maximum
sum throughput. Finally, the required number of cooperative precoder feedback
bits is derived for limiting the throughput loss due to precoder quantization.Comment: 23 pages; 5 figures; this work was presented in part at Asilomar 2011
and will appear in IEEE Trans. on Wireless Com
Envelope Word and Gap Sequence in Doubling Sequence
Let be a factor of Doubling sequence , then
it occurs in the sequence infinitely many times. Let be the -th
occurrence of and be the gap between and
. In this paper, we discuss the structure of the gap sequence
. We prove that all factors can be divided into two
types, one type has exactly two distinct gaps and ,
the other type has exactly three distinct gaps , and
. We determine the expressions of gaps completely. And also give
the substitution of each gap sequence. The main tool in this paper is "envelope
word", which is a new notion, denoted by . As an application, we
determine the positions of all , discuss some combinatorial
properties of factors, and count the distinct squares beginning in
for .Comment: 14 pages, 7 figures. arXiv admin note: text overlap with
arXiv:1408.372
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