31,114 research outputs found
The log term of Szego Kernel
In this paper, we study the relations between the log term of the Szeg\"o
kernel of the unit circle bundle of the dual line bundle of an ample line
bundle over a compact K\"ahlermanifold. We proved a local rigidity theorem. The
result is related to the classical Ramadanov Conjecture.Comment: We corrected a typo in the title in this versio
Metric Learning in Codebook Generation of Bag-of-Words for Person Re-identification
Person re-identification is generally divided into two part: first how to
represent a pedestrian by discriminative visual descriptors and second how to
compare them by suitable distance metrics. Conventional methods isolate these
two parts, the first part usually unsupervised and the second part supervised.
The Bag-of-Words (BoW) model is a widely used image representing descriptor in
part one. Its codebook is simply generated by clustering visual features in
Euclidian space. In this paper, we propose to use part two metric learning
techniques in the codebook generation phase of BoW. In particular, the proposed
codebook is clustered under Mahalanobis distance which is learned supervised.
Extensive experiments prove that our proposed method is effective. With several
low level features extracted on superpixel and fused together, our method
outperforms state-of-the-art on person re-identification benchmarks including
VIPeR, PRID450S, and Market1501
Phase-Aligned Spectral Filtering for Decomposing Spatiotemporal Dynamics
Spatiotemporal dynamics is central to a wide range of applications from
climatology, computer vision to neural sciences. From temporal observations
taken on a high-dimensional vector of spatial locations, we seek to derive
knowledge about such dynamics via data assimilation and modeling. It is assumed
that the observed spatiotemporal data represent superimposed lower-rank smooth
oscillations and movements from a generative dynamic system, mixed with
higher-rank random noises. Separating the signals from noises is essential for
us to visualize, model and understand these lower-rank dynamic systems. It is
also often the case that such a lower-rank dynamic system have multiple
independent components, corresponding to different trends or functionalities of
the system under study. In this paper, we present a novel filtering framework
for identifying lower-rank dynamics and its components embedded in a high
dimensional spatiotemporal system. It is based on an approach of structural
decomposition and phase-aligned construction in the frequency domain. In both
our simulated examples and real data applications, we illustrate that the
proposed method is able to separate and identify meaningful lower-rank
movements, while existing methods fail.Comment: 29 pages, 10 figure
Constructing virtual Euler cycles and classes
The constructions of the virtual Euler (or moduli) cycles and their
properties are explained and developed systematically in the general abstract
settings.Comment: 181 pages, V2; Section 2.1 is rewritten; a new Section 2.2 is added;
the original Section 2.2-Section 2.7 become Section 2.3-Section 2.8; Sections
3,4 are rewritten; other places have also some small change
Extending PPTL for Verifying Heap Evolution Properties
In this paper, we integrate separation logic with Propositional Projection
Temporal Logic (PPTL) to obtain a two-dimensional logic, namely
PPTL^{\tiny\mbox{SL}}. The spatial dimension is realized by a decidable
fragment of separation logic which can be used to describe linked lists, and
the temporal dimension is expressed by PPTL. We show that PPTL and
PPTL^{\tiny\mbox{SL}} are closely related in their syntax structures. That
is, for any PPTL^{\tiny\mbox{SL}} formula in a restricted form, there exists
an "isomorphic" PPTL formula. The "isomorphic" PPTL formulas can be obtained by
first an equisatisfiable translation and then an isomorphic mapping. As a
result, existing theory of PPTL, such as decision procedure for satisfiability
and model checking algorithm, can be reused for PPTL^{\tiny\mbox{SL}}
Evaluating Surrogate Marker Information using Censored Data
Given the long follow-up periods that are often required for treatment or
intervention studies, the potential to use surrogate markers to decrease the
required follow-up time is a very attractive goal. However, previous studies
have shown that using inadequate markers or making inappropriate assumptions
about the relationship between the primary outcome and surrogate marker can
lead to inaccurate conclusions regarding the treatment effect. Currently
available methods for identifying and validating surrogate markers tend to rely
on restrictive model assumptions and/or focus on uncensored outcomes. The
ability to use such methods in practice when the primary outcome of interest is
a time-to-event outcome is difficult due to censoring and missing surrogate
information among those who experience the primary outcome before surrogate
marker measurement. In this paper, we propose a novel definition of the
proportion of treatment effect explained by surrogate information collected up
to a specified time in the setting of a time-to-event primary outcome. Our
proposed approach accommodates a setting where individuals may experience the
primary outcome before the surrogate marker is measured. We propose a robust
nonparametric procedure to estimate the defined quantity using censored data
and use a perturbation-resampling procedure for variance estimation. Simulation
studies demonstrate that the proposed procedures perform well in finite
samples. We illustrate the proposed procedures by investigating two potential
surrogate markers for diabetes using data from the Diabetes Prevention Program.Comment: This article has been submitted to Statistics in Medicin
WeText: Scene Text Detection under Weak Supervision
The requiring of large amounts of annotated training data has become a common
constraint on various deep learning systems. In this paper, we propose a weakly
supervised scene text detection method (WeText) that trains robust and accurate
scene text detection models by learning from unannotated or weakly annotated
data. With a "light" supervised model trained on a small fully annotated
dataset, we explore semi-supervised and weakly supervised learning on a large
unannotated dataset and a large weakly annotated dataset, respectively. For the
unsupervised learning, the light supervised model is applied to the unannotated
dataset to search for more character training samples, which are further
combined with the small annotated dataset to retrain a superior character
detection model. For the weakly supervised learning, the character searching is
guided by high-level annotations of words/text lines that are widely available
and also much easier to prepare. In addition, we design an unified scene
character detector by adapting regression based deep networks, which greatly
relieves the error accumulation issue that widely exists in most traditional
approaches. Extensive experiments across different unannotated and weakly
annotated datasets show that the scene text detection performance can be
clearly boosted under both scenarios, where the weakly supervised learning can
achieve the state-of-the-art performance by using only 229 fully annotated
scene text images.Comment: accepted by ICCV201
Amplitude Space Sharing among the Macro-Cell and Small-Cell Users
The crushing demand for wireless data services will soon exceed the
capability of the current homogeneous cellular architecture. An emerging
solution is to overlay small-cell networks with the macro-cell networks. In
this paper, we propose an amplitude space sharing (ASS) method among the
macro-cell user and small-cell users. By transmit layer design and data-rate
optimization, the signals and interferences are promised to be separable at
each receiver and the network sum-rate is maximized. The Han-Koboyashi coding
is employed and optimal power allocation is derived for the one small-cell
scenario, and a simple ASS transmission scheme is developed for the multiple
small-cells scenarios. Simulation results show great superiority over other
interference management schemes.Comment: 6 pages, 5 figures, submitted to IEEE Int. Conf. on Communications
(ICC) 201
A note on uniformization of Riemann surfaces by Ricci flow
In this note we clarify that the Rcci flow can be used to give an independent
proof of the uniformization theorem of Riemann surfaces.Comment: 3 pages, no figure, minor change
An interpretable LSTM neural network for autoregressive exogenous model
In this paper, we propose an interpretable LSTM recurrent neural network,
i.e., multi-variable LSTM for time series with exogenous variables. Currently,
widely used attention mechanism in recurrent neural networks mostly focuses on
the temporal aspect of data and falls short of characterizing variable
importance. To this end, our multi-variable LSTM equipped with tensorized
hidden states is developed to learn variable specific representations, which
give rise to both temporal and variable level attention. Preliminary
experiments demonstrate comparable prediction performance of multi-variable
LSTM w.r.t. encoder-decoder based baselines. More interestingly, variable
importance in real datasets characterized by the variable attention is highly
in line with that determined by statistical Granger causality test, which
exhibits the prospect of multi-variable LSTM as a simple and uniform end-to-end
framework for both forecasting and knowledge discovery
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