230 research outputs found
Learning with Augmented Features for Heterogeneous Domain Adaptation
We propose a new learning method for heterogeneous domain adaptation (HDA),
in which the data from the source domain and the target domain are represented
by heterogeneous features with different dimensions. Using two different
projection matrices, we first transform the data from two domains into a common
subspace in order to measure the similarity between the data from two domains.
We then propose two new feature mapping functions to augment the transformed
data with their original features and zeros. The existing learning methods
(e.g., SVM and SVR) can be readily incorporated with our newly proposed
augmented feature representations to effectively utilize the data from both
domains for HDA. Using the hinge loss function in SVM as an example, we
introduce the detailed objective function in our method called Heterogeneous
Feature Augmentation (HFA) for a linear case and also describe its
kernelization in order to efficiently cope with the data with very high
dimensions. Moreover, we also develop an alternating optimization algorithm to
effectively solve the nontrivial optimization problem in our HFA method.
Comprehensive experiments on two benchmark datasets clearly demonstrate that
HFA outperforms the existing HDA methods.Comment: ICML201
MiniMax Entropy Network: Learning Category-Invariant Features for Domain Adaptation
How to effectively learn from unlabeled data from the target domain is
crucial for domain adaptation, as it helps reduce the large performance gap due
to domain shift or distribution change. In this paper, we propose an
easy-to-implement method dubbed MiniMax Entropy Networks (MMEN) based on
adversarial learning. Unlike most existing approaches which employ a generator
to deal with domain difference, MMEN focuses on learning the categorical
information from unlabeled target samples with the help of labeled source
samples. Specifically, we set an unfair multi-class classifier named
categorical discriminator, which classifies source samples accurately but be
confused about the categories of target samples. The generator learns a common
subspace that aligns the unlabeled samples based on the target pseudo-labels.
For MMEN, we also provide theoretical explanations to show that the learning of
feature alignment reduces domain mismatch at the category level. Experimental
results on various benchmark datasets demonstrate the effectiveness of our
method over existing state-of-the-art baselines.Comment: 8 pages, 6 figure
Electronic structure of self-assembled InAs/InP quantum dots: A Comparison with self-assembled InAs/GaAs quantum dots
We investigate the electronic structure of the InAs/InP quantum dots using an
atomistic pseudopotential method and compare them to those of the InAs/GaAs
QDs. We show that even though the InAs/InP and InAs/GaAs dots have the same dot
material, their electronic structure differ significantly in certain aspects,
especially for holes: (i) The hole levels have a much larger energy spacing in
the InAs/InP dots than in the InAs/GaAs dots of corresponding size. (ii)
Furthermore, in contrast with the InAs/GaAs dots, where the sizeable hole ,
intra-shell level splitting smashes the energy level shell structure, the
InAs/InP QDs have a well defined energy level shell structure with small ,
level splitting, for holes. (iii) The fundamental exciton energies of the
InAs/InP dots are calculated to be around 0.8 eV ( 1.55 m), about
200 meV lower than those of typical InAs/GaAs QDs, mainly due to the smaller
lattice mismatch in the InAs/InP dots. (iii) The widths of the exciton
shell and shell are much narrower in the InAs/InP dots than in the
InAs/GaAs dots. (iv) The InAs/GaAs and InAs/InP dots have a reversed light
polarization anisotropy along the [100] and [10] directions
Learning Motion Refinement for Unsupervised Face Animation
Unsupervised face animation aims to generate a human face video based on the
appearance of a source image, mimicking the motion from a driving video.
Existing methods typically adopted a prior-based motion model (e.g., the local
affine motion model or the local thin-plate-spline motion model). While it is
able to capture the coarse facial motion, artifacts can often be observed
around the tiny motion in local areas (e.g., lips and eyes), due to the limited
ability of these methods to model the finer facial motions. In this work, we
design a new unsupervised face animation approach to learn simultaneously the
coarse and finer motions. In particular, while exploiting the local affine
motion model to learn the global coarse facial motion, we design a novel motion
refinement module to compensate for the local affine motion model for modeling
finer face motions in local areas. The motion refinement is learned from the
dense correlation between the source and driving images. Specifically, we first
construct a structure correlation volume based on the keypoint features of the
source and driving images. Then, we train a model to generate the tiny facial
motions iteratively from low to high resolution. The learned motion refinements
are combined with the coarse motion to generate the new image. Extensive
experiments on widely used benchmarks demonstrate that our method achieves the
best results among state-of-the-art baselines.Comment: NeurIPS 202
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