601 research outputs found
Constructing Hierarchical Image-tags Bimodal Representations for Word Tags Alternative Choice
This paper describes our solution to the multi-modal learning challenge of
ICML. This solution comprises constructing three-level representations in three
consecutive stages and choosing correct tag words with a data-specific
strategy. Firstly, we use typical methods to obtain level-1 representations.
Each image is represented using MPEG-7 and gist descriptors with additional
features released by the contest organizers. And the corresponding word tags
are represented by bag-of-words model with a dictionary of 4000 words.
Secondly, we learn the level-2 representations using two stacked RBMs for each
modality. Thirdly, we propose a bimodal auto-encoder to learn the
similarities/dissimilarities between the pairwise image-tags as level-3
representations. Finally, during the test phase, based on one observation of
the dataset, we come up with a data-specific strategy to choose the correct tag
words leading to a leap of an improved overall performance. Our final average
accuracy on the private test set is 100%, which ranks the first place in this
challenge.Comment: 6 pages, 1 figure, Presented at the Workshop on Representation
Learning, ICML 201
Role of the effective payoff function in evolutionary game dynamics
In most studies regarding evolutionary game dynamics, the effective payoff, a
quantity that translates the payoff derived from game interactions into
reproductive success, is usually assumed to be a specific function of the
payoff. Meanwhile, the effect of different function forms of effective payoff
on evolutionary dynamics is always left in the basket. With introducing a
generalized mapping that the effective payoff of individuals is a non-negative
function of two variables on selection intensity and payoff, we study how
different effective payoff functions affect evolutionary dynamics in a
symmetrical mutation-selection process. For standard two-strategy two-player
games, we find that under weak selection the condition for one strategy to
dominate the other depends not only on the classical {\sigma}-rule, but also on
an extra constant that is determined by the form of the effective payoff
function. By changing the sign of the constant, we can alter the direction of
strategy selection. Taking the Moran process and pairwise comparison process as
specific models in well-mixed populations, we find that different fitness or
imitation mappings are equivalent under weak selection. Moreover, the sign of
the extra constant determines the direction of one-third law and risk-dominance
for sufficiently large populations. This work thus helps to elucidate how the
effective payoff function as another fundamental ingredient of evolution affect
evolutionary dynamics.Comment: This paper has been accepted to publish on EP
Influence of initial distributions on robust cooperation in evolutionary Prisoner's Dilemma
We study the evolutionary Prisoner's Dilemma game on scale-free networks for
different initial distributions. We consider three types of initial
distributions for cooperators and defectors: initially random distribution with
different frequencies of defectors; intentional organization with defectors
initially occupying the most connected nodes with different fractions of
defectors; intentional assignment for cooperators occupying the most connected
nodes with different proportions of defectors at the beginning. It is shown
that initial configurations for cooperators and defectors can influence the
stationary level of cooperation and the evolution speed of cooperation.
Organizations with the vertices with highest connectivity representing
individuals cooperators could exhibit the most robust cooperation and drive
evolutionary process to converge fastest to the high steady cooperation in the
three situations of initial distributions. Otherwise, we determine the critical
initial frequencies of defectors above which the extinction of cooperators
occurs for the respective initial distributions, and find that the presence of
network loops and clusters for cooperators can favor the emergence of
cooperation.Comment: Submitted to EP
Training Group Orthogonal Neural Networks with Privileged Information
Learning rich and diverse representations is critical for the performance of
deep convolutional neural networks (CNNs). In this paper, we consider how to
use privileged information to promote inherent diversity of a single CNN model
such that the model can learn better representations and offer stronger
generalization ability. To this end, we propose a novel group orthogonal
convolutional neural network (GoCNN) that learns untangled representations
within each layer by exploiting provided privileged information and enhances
representation diversity effectively. We take image classification as an
example where image segmentation annotations are used as privileged information
during the training process. Experiments on two benchmark datasets -- ImageNet
and PASCAL VOC -- clearly demonstrate the strong generalization ability of our
proposed GoCNN model. On the ImageNet dataset, GoCNN improves the performance
of state-of-the-art ResNet-152 model by absolute value of 1.2% while only uses
privileged information of 10% of the training images, confirming effectiveness
of GoCNN on utilizing available privileged knowledge to train better CNNs.Comment: Proceedings of the IJCAI-1
Deep Self-Taught Learning for Weakly Supervised Object Localization
Most existing weakly supervised localization (WSL) approaches learn detectors
by finding positive bounding boxes based on features learned with image-level
supervision. However, those features do not contain spatial location related
information and usually provide poor-quality positive samples for training a
detector. To overcome this issue, we propose a deep self-taught learning
approach, which makes the detector learn the object-level features reliable for
acquiring tight positive samples and afterwards re-train itself based on them.
Consequently, the detector progressively improves its detection ability and
localizes more informative positive samples. To implement such self-taught
learning, we propose a seed sample acquisition method via image-to-object
transferring and dense subgraph discovery to find reliable positive samples for
initializing the detector. An online supportive sample harvesting scheme is
further proposed to dynamically select the most confident tight positive
samples and train the detector in a mutual boosting way. To prevent the
detector from being trapped in poor optima due to overfitting, we propose a new
relative improvement of predicted CNN scores for guiding the self-taught
learning process. Extensive experiments on PASCAL 2007 and 2012 show that our
approach outperforms the state-of-the-arts, strongly validating its
effectiveness.Comment: Accepted as spotlight paper by CVPR 201
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