1,901 research outputs found
Jointly Learning Non-negative Projection and Dictionary with Discriminative Graph Constraints for Classification
Sparse coding with dictionary learning (DL) has shown excellent
classification performance. Despite the considerable number of existing works,
how to obtain features on top of which dictionaries can be better learned
remains an open and interesting question. Many current prevailing DL methods
directly adopt well-performing crafted features. While such strategy may
empirically work well, it ignores certain intrinsic relationship between
dictionaries and features. We propose a framework where features and
dictionaries are jointly learned and optimized. The framework, named joint
non-negative projection and dictionary learning (JNPDL), enables interaction
between the input features and the dictionaries. The non-negative projection
leads to discriminative parts-based object features while DL seeks a more
suitable representation. Discriminative graph constraints are further imposed
to simultaneously maximize intra-class compactness and inter-class
separability. Experiments on both image and image set classification show the
excellent performance of JNPDL by outperforming several state-of-the-art
approaches.Comment: To appear in BMVC 201
Supervised Dictionary Learning and Sparse Representation-A Review
Dictionary learning and sparse representation (DLSR) is a recent and
successful mathematical model for data representation that achieves
state-of-the-art performance in various fields such as pattern recognition,
machine learning, computer vision, and medical imaging. The original
formulation for DLSR is based on the minimization of the reconstruction error
between the original signal and its sparse representation in the space of the
learned dictionary. Although this formulation is optimal for solving problems
such as denoising, inpainting, and coding, it may not lead to optimal solution
in classification tasks, where the ultimate goal is to make the learned
dictionary and corresponding sparse representation as discriminative as
possible. This motivated the emergence of a new category of techniques, which
is appropriately called supervised dictionary learning and sparse
representation (S-DLSR), leading to more optimal dictionary and sparse
representation in classification tasks. Despite many research efforts for
S-DLSR, the literature lacks a comprehensive view of these techniques, their
connections, advantages and shortcomings. In this paper, we address this gap
and provide a review of the recently proposed algorithms for S-DLSR. We first
present a taxonomy of these algorithms into six categories based on the
approach taken to include label information into the learning of the dictionary
and/or sparse representation. For each category, we draw connections between
the algorithms in this category and present a unified framework for them. We
then provide guidelines for applied researchers on how to represent and learn
the building blocks of an S-DLSR solution based on the problem at hand. This
review provides a broad, yet deep, view of the state-of-the-art methods for
S-DLSR and allows for the advancement of research and development in this
emerging area of research
Discriminative Supervised Hashing for Cross-Modal similarity Search
With the advantage of low storage cost and high retrieval efficiency, hashing
techniques have recently been an emerging topic in cross-modal similarity
search. As multiple modal data reflect similar semantic content, many
researches aim at learning unified binary codes. However, discriminative
hashing features learned by these methods are not adequate. This results in
lower accuracy and robustness. We propose a novel hashing learning framework
which jointly performs classifier learning, subspace learning and matrix
factorization to preserve class-specific semantic content, termed
Discriminative Supervised Hashing (DSH), to learn the discrimative unified
binary codes for multi-modal data. Besides, reducing the loss of information
and preserving the non-linear structure of data, DSH non-linearly projects
different modalities into the common space in which the similarity among
heterogeneous data points can be measured. Extensive experiments conducted on
the three publicly available datasets demonstrate that the framework proposed
in this paper outperforms several state-of -the-art methods.Comment: 7 pages,3 figures,4 tables;The paper is under consideration at Image
and Vision Computin
Graph Embedding Techniques, Applications, and Performance: A Survey
Graphs, such as social networks, word co-occurrence networks, and
communication networks, occur naturally in various real-world applications.
Analyzing them yields insight into the structure of society, language, and
different patterns of communication. Many approaches have been proposed to
perform the analysis. Recently, methods which use the representation of graph
nodes in vector space have gained traction from the research community. In this
survey, we provide a comprehensive and structured analysis of various graph
embedding techniques proposed in the literature. We first introduce the
embedding task and its challenges such as scalability, choice of
dimensionality, and features to be preserved, and their possible solutions. We
then present three categories of approaches based on factorization methods,
random walks, and deep learning, with examples of representative algorithms in
each category and analysis of their performance on various tasks. We evaluate
these state-of-the-art methods on a few common datasets and compare their
performance against one another. Our analysis concludes by suggesting some
potential applications and future directions. We finally present the
open-source Python library we developed, named GEM (Graph Embedding Methods,
available at https://github.com/palash1992/GEM), which provides all presented
algorithms within a unified interface to foster and facilitate research on the
topic.Comment: Submitted to Knowledge Based Systems for revie
Triplet-Based Deep Hashing Network for Cross-Modal Retrieval
Given the benefits of its low storage requirements and high retrieval
efficiency, hashing has recently received increasing attention. In
particular,cross-modal hashing has been widely and successfully used in
multimedia similarity search applications. However, almost all existing methods
employing cross-modal hashing cannot obtain powerful hash codes due to their
ignoring the relative similarity between heterogeneous data that contains
richer semantic information, leading to unsatisfactory retrieval performance.
In this paper, we propose a triplet-based deep hashing (TDH) network for
cross-modal retrieval. First, we utilize the triplet labels, which describes
the relative relationships among three instances as supervision in order to
capture more general semantic correlations between cross-modal instances. We
then establish a loss function from the inter-modal view and the intra-modal
view to boost the discriminative abilities of the hash codes. Finally, graph
regularization is introduced into our proposed TDH method to preserve the
original semantic similarity between hash codes in Hamming space. Experimental
results show that our proposed method outperforms several state-of-the-art
approaches on two popular cross-modal datasets
A Comprehensive Survey of Graph Embedding: Problems, Techniques and Applications
Graph is an important data representation which appears in a wide diversity
of real-world scenarios. Effective graph analytics provides users a deeper
understanding of what is behind the data, and thus can benefit a lot of useful
applications such as node classification, node recommendation, link prediction,
etc. However, most graph analytics methods suffer the high computation and
space cost. Graph embedding is an effective yet efficient way to solve the
graph analytics problem. It converts the graph data into a low dimensional
space in which the graph structural information and graph properties are
maximally preserved. In this survey, we conduct a comprehensive review of the
literature in graph embedding. We first introduce the formal definition of
graph embedding as well as the related concepts. After that, we propose two
taxonomies of graph embedding which correspond to what challenges exist in
different graph embedding problem settings and how the existing work address
these challenges in their solutions. Finally, we summarize the applications
that graph embedding enables and suggest four promising future research
directions in terms of computation efficiency, problem settings, techniques and
application scenarios.Comment: A 20-page comprehensive survey of graph/network embedding for over
150+ papers till year 2018. It provides systematic categorization of
problems, techniques and applications. Accepted by IEEE Transactions on
Knowledge and Data Engineering (TKDE). Comments and suggestions are welcomed
for continuously improving this surve
Attribute-Guided Network for Cross-Modal Zero-Shot Hashing
Zero-Shot Hashing aims at learning a hashing model that is trained only by
instances from seen categories but can generate well to those of unseen
categories. Typically, it is achieved by utilizing a semantic embedding space
to transfer knowledge from seen domain to unseen domain. Existing efforts
mainly focus on single-modal retrieval task, especially Image-Based Image
Retrieval (IBIR). However, as a highlighted research topic in the field of
hashing, cross-modal retrieval is more common in real world applications. To
address the Cross-Modal Zero-Shot Hashing (CMZSH) retrieval task, we propose a
novel Attribute-Guided Network (AgNet), which can perform not only IBIR, but
also Text-Based Image Retrieval (TBIR). In particular, AgNet aligns different
modal data into a semantically rich attribute space, which bridges the gap
caused by modality heterogeneity and zero-shot setting. We also design an
effective strategy that exploits the attribute to guide the generation of hash
codes for image and text within the same network. Extensive experimental
results on three benchmark datasets (AwA, SUN, and ImageNet) demonstrate the
superiority of AgNet on both cross-modal and single-modal zero-shot image
retrieval tasks.Comment: 9 pages, 8 figure
Joint Label Prediction based Semi-Supervised Adaptive Concept Factorization for Robust Data Representation
Constrained Concept Factorization (CCF) yields the enhanced representation
ability over CF by incorporating label information as additional constraints,
but it cannot classify and group unlabeled data appropriately. Minimizing the
difference between the original data and its reconstruction directly can enable
CCF to model a small noisy perturbation, but is not robust to gross sparse
errors. Besides, CCF cannot preserve the manifold structures in new
representation space explicitly, especially in an adaptive manner. In this
paper, we propose a joint label prediction based Robust Semi-Supervised
Adaptive Concept Factorization (RS2ACF) framework. To obtain robust
representation, RS2ACF relaxes the factorization to make it simultaneously
stable to small entrywise noise and robust to sparse errors. To enrich prior
knowledge to enhance the discrimination, RS2ACF clearly uses class information
of labeled data and more importantly propagates it to unlabeled data by jointly
learning an explicit label indicator for unlabeled data. By the label
indicator, RS2ACF can ensure the unlabeled data of the same predicted label to
be mapped into the same class in feature space. Besides, RS2ACF incorporates
the joint neighborhood reconstruction error over the new representations and
predicted labels of both labeled and unlabeled data, so the manifold structures
can be preserved explicitly and adaptively in the representation space and
label space at the same time. Owing to the adaptive manner, the tricky process
of determining the neighborhood size or kernel width can be avoided. Extensive
results on public databases verify that our RS2ACF can deliver state-of-the-art
data representation, compared with other related methods.Comment: Accepted at IEEE TKD
A Tale of Three Probabilistic Families: Discriminative, Descriptive and Generative Models
The pattern theory of Grenander is a mathematical framework where patterns
are represented by probability models on random variables of algebraic
structures. In this paper, we review three families of probability models,
namely, the discriminative models, the descriptive models, and the generative
models. A discriminative model is in the form of a classifier. It specifies the
conditional probability of the class label given the input signal. A
descriptive model specifies the probability distribution of the signal, based
on an energy function defined on the signal. A generative model assumes that
the signal is generated by some latent variables via a transformation. We shall
review these models within a common framework and explore their connections. We
shall also review the recent developments that take advantage of the high
approximation capacities of deep neural networks
Information Extraction from Scientific Literature for Method Recommendation
As a research community grows, more and more papers are published each year.
As a result there is increasing demand for improved methods for finding
relevant papers, automatically understanding the key ideas and recommending
potential methods for a target problem. Despite advances in search engines, it
is still hard to identify new technologies according to a researcher's need.
Due to the large variety of domains and extremely limited annotated resources,
there has been relatively little work on leveraging natural language processing
in scientific recommendation. In this proposal, we aim at making scientific
recommendations by extracting scientific terms from a large collection of
scientific papers and organizing the terms into a knowledge graph. In
preliminary work, we trained a scientific term extractor using a small amount
of annotated data and obtained state-of-the-art performance by leveraging large
amount of unannotated papers through applying multiple semi-supervised
approaches. We propose to construct a knowledge graph in a way that can make
minimal use of hand annotated data, using only the extracted terms,
unsupervised relational signals such as co-occurrence, and structural external
resources such as Wikipedia. Latent relations between scientific terms can be
learned from the graph. Recommendations will be made through graph inference
for both observed and unobserved relational pairs.Comment: Thesis Proposal. arXiv admin note: text overlap with arXiv:1708.0607
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