10,128 research outputs found
Recurrent Pixel Embedding for Instance Grouping
We introduce a differentiable, end-to-end trainable framework for solving
pixel-level grouping problems such as instance segmentation consisting of two
novel components. First, we regress pixels into a hyper-spherical embedding
space so that pixels from the same group have high cosine similarity while
those from different groups have similarity below a specified margin. We
analyze the choice of embedding dimension and margin, relating them to
theoretical results on the problem of distributing points uniformly on the
sphere. Second, to group instances, we utilize a variant of mean-shift
clustering, implemented as a recurrent neural network parameterized by kernel
bandwidth. This recurrent grouping module is differentiable, enjoys convergent
dynamics and probabilistic interpretability. Backpropagating the group-weighted
loss through this module allows learning to focus on only correcting embedding
errors that won't be resolved during subsequent clustering. Our framework,
while conceptually simple and theoretically abundant, is also practically
effective and computationally efficient. We demonstrate substantial
improvements over state-of-the-art instance segmentation for object proposal
generation, as well as demonstrating the benefits of grouping loss for
classification tasks such as boundary detection and semantic segmentation
Continuous non-revisiting genetic algorithm
The non-revisiting genetic algorithm (NrGA) is extended to handle continuous search space. The extended NrGA model, Continuous NrGA (cNrGA), employs the same tree-structure archive of NrGA to memorize the evaluated solutions, in which the search space is divided into non-overlapped partitions according to the distribution of the solutions. cNrGA is a bi-modulus evolutionary algorithm consisting of the genetic algorithm module (GAM) and the adaptive mutation module (AMM). When GAM generates an offspring, the offspring is sent to AMM and is mutated according to the density of the solutions stored in the memory archive. For a point in the search space with high solution-density, it infers a high probability that the point is close to the optimum and hence a near search is suggested. Alternatively, a far search is recommended for a point with low solution-density. Benefitting from the space partitioning scheme, a fast solution-density approximation is obtained. Also, the adaptive mutation scheme naturally avoid the generation of out-of-bound solutions. The performance of cNrGA is tested on 14 benchmark functions on dimensions ranging from 2 to 40. It is compared with real coded GA, differential evolution, covariance matrix adaptation evolution strategy and two improved particle swarm optimization. The simulation results show that cNrGA outperforms the other algorithms for multi-modal function optimization.published_or_final_versio
Separation of pulsar signals from noise with supervised machine learning algorithms
We evaluate the performance of four different machine learning (ML)
algorithms: an Artificial Neural Network Multi-Layer Perceptron (ANN MLP ),
Adaboost, Gradient Boosting Classifier (GBC), XGBoost, for the separation of
pulsars from radio frequency interference (RFI) and other sources of noise,
using a dataset obtained from the post-processing of a pulsar search pi peline.
This dataset was previously used for cross-validation of the SPINN-based
machine learning engine, used for the reprocessing of HTRU-S survey data
arXiv:1406.3627. We have used Synthetic Minority Over-sampling Technique
(SMOTE) to deal with high class imbalance in the dataset. We report a variety
of quality scores from all four of these algorithms on both the non-SMOTE and
SMOTE datasets. For all the above ML methods, we report high accuracy and
G-mean in both the non-SMOTE and SMOTE cases. We study the feature importances
using Adaboost, GBC, and XGBoost and also from the minimum Redundancy Maximum
Relevance approach to report algorithm-agnostic feature ranking. From these
methods, we find that the signal to noise of the folded profile to be the best
feature. We find that all the ML algorithms report FPRs about an order of
magnitude lower than the corresponding FPRs obtained in arXiv:1406.3627, for
the same recall value.Comment: 14 pages, 2 figures. Accepted for publication in Astronomy and
Computin
Large-scale Land Cover Classification in GaoFen-2 Satellite Imagery
Many significant applications need land cover information of remote sensing
images that are acquired from different areas and times, such as change
detection and disaster monitoring. However, it is difficult to find a generic
land cover classification scheme for different remote sensing images due to the
spectral shift caused by diverse acquisition condition. In this paper, we
develop a novel land cover classification method that can deal with large-scale
data captured from widely distributed areas and different times. Additionally,
we establish a large-scale land cover classification dataset consisting of 150
Gaofen-2 imageries as data support for model training and performance
evaluation. Our experiments achieve outstanding classification accuracy
compared with traditional methods.Comment: IGARSS'18 conference pape
Deep Learning for User Comment Moderation
Experimenting with a new dataset of 1.6M user comments from a Greek news
portal and existing datasets of English Wikipedia comments, we show that an RNN
outperforms the previous state of the art in moderation. A deep,
classification-specific attention mechanism improves further the overall
performance of the RNN. We also compare against a CNN and a word-list baseline,
considering both fully automatic and semi-automatic moderation
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