516 research outputs found
Distributed Representations of Signed Networks
Recent successes in word embedding and document embedding have motivated
researchers to explore similar representations for networks and to use such
representations for tasks such as edge prediction, node label prediction, and
community detection. Such network embedding methods are largely focused on
finding distributed representations for unsigned networks and are unable to
discover embeddings that respect polarities inherent in edges. We propose
SIGNet, a fast scalable embedding method suitable for signed networks. Our
proposed objective function aims to carefully model the social structure
implicit in signed networks by reinforcing the principles of social balance
theory. Our method builds upon the traditional word2vec family of embedding
approaches and adds a new targeted node sampling strategy to maintain
structural balance in higher-order neighborhoods. We demonstrate the
superiority of SIGNet over state-of-the-art methods proposed for both signed
and unsigned networks on several real world datasets from different domains. In
particular, SIGNet offers an approach to generate a richer vocabulary of
features of signed networks to support representation and reasoning.Comment: Published in PAKDD 201
Structural Material Property Tailoring Using Deep Neural Networks
Advances in robotics, artificial intelligence, and machine learning are
ushering in a new age of automation, as machines match or outperform human
performance. Machine intelligence can enable businesses to improve performance
by reducing errors, improving sensitivity, quality and speed, and in some cases
achieving outcomes that go beyond current resource capabilities. Relevant
applications include new product architecture design, rapid material
characterization, and life-cycle management tied with a digital strategy that
will enable efficient development of products from cradle to grave. In
addition, there are also challenges to overcome that must be addressed through
a major, sustained research effort that is based solidly on both inferential
and computational principles applied to design tailoring of functionally
optimized structures. Current applications of structural materials in the
aerospace industry demand the highest quality control of material
microstructure, especially for advanced rotational turbomachinery in aircraft
engines in order to have the best tailored material property. In this paper,
deep convolutional neural networks were developed to accurately predict
processing-structure-property relations from materials microstructures images,
surpassing current best practices and modeling efforts. The models
automatically learn critical features, without the need for manual
specification and/or subjective and expensive image analysis. Further, in
combination with generative deep learning models, a framework is proposed to
enable rapid material design space exploration and property identification and
optimization. The implementation must take account of real-time decision cycles
and the trade-offs between speed and accuracy
Convolutional LSTM Networks for Subcellular Localization of Proteins
Machine learning is widely used to analyze biological sequence data.
Non-sequential models such as SVMs or feed-forward neural networks are often
used although they have no natural way of handling sequences of varying length.
Recurrent neural networks such as the long short term memory (LSTM) model on
the other hand are designed to handle sequences. In this study we demonstrate
that LSTM networks predict the subcellular location of proteins given only the
protein sequence with high accuracy (0.902) outperforming current state of the
art algorithms. We further improve the performance by introducing convolutional
filters and experiment with an attention mechanism which lets the LSTM focus on
specific parts of the protein. Lastly we introduce new visualizations of both
the convolutional filters and the attention mechanisms and show how they can be
used to extract biological relevant knowledge from the LSTM networks
Adaptive Sampling for Nonlinear Dimensionality Reduction Based on Manifold Learning
We make use of the non-intrusive dimensionality reduction method Isomap in order to emulate nonlinear parametric flow problems that are governed by the Reynolds-averaged Navier-Stokes equations. Isomap is a manifold learning approach that provides a low-dimensional embedding space that is approximately isometric to the manifold that is assumed to be formed by the high-fidelity Navier-Stokes flow solutions under smooth variations of the inflow conditions. The focus of the work at hand is the adaptive construction and refinement of the Isomap emulator: We exploit the non-Euclidean Isomap metric to detect and fill up gaps in the sampling in the embedding space. The performance of the proposed manifold filling method will be illustrated by numerical experiments, where we consider nonlinear parameter-dependent steady-state Navier-Stokes flows in the transonic regime
Photometric stereo for 3D face reconstruction using non-linear illumination models
Face recognition in presence of illumination changes, variant pose and different facial expressions is a challenging problem. In this paper, a method for 3D face reconstruction using photometric stereo and without knowing the illumination directions and facial expression is proposed in order to achieve improvement in face recognition. A dimensionality reduction method was introduced to represent the face deformations due to illumination variations and self shadows in a lower space. The obtained mapping function was used to determine the illumination direction of each input image and that direction was used to apply photometric stereo. Experiments with faces were performed in order to evaluate the performance of the proposed scheme. From the experiments it was shown that the proposed approach results very accurate 3D surfaces without knowing the light directions and with a very small differences compared to the case of known directions. As a result the proposed approach is more general and requires less restrictions enabling 3D face recognition methods to operate with less data
A Joint Local and Global Deep Metric Learning Method for Caricature Recognition
Caricature recognition is a novel, interesting, yet challenging problem. Due to the exaggeration and distortion, there is a large cross-modal gap between photographs and caricatures, making it nontrivial to match the features of photographs and caricatures. To address the problem, a joint local and global metric learning method (LGDML) is proposed. First, joint local and global feature representation is learnt with convolutional neural networks to find both discriminant features of local facial parts and global distinctive features of the whole face. Next, in order to fuse the local and global similarities of features, a unified feature representation and similarity measure learning framework is proposed. Various methods are evaluated on the caricature recognition task. We have verified that both local and global features are crucial for caricature recognition. Moreover, experimental results show that, compared with the state-of-the-art methods, LGDML can obtain superior performance in terms of Rank-1 and Rank-10
A network analysis to identify pathophysiological pathways distinguishing ischaemic from non-ischaemic heart failure
Aims
Heart failure (HF) is frequently caused by an ischaemic event (e.g. myocardial infarction) but might also be caused by a primary disease of the myocardium (cardiomyopathy). In order to identify targeted therapies specific for either ischaemic or nonâischaemic HF, it is important to better understand differences in underlying molecular mechanisms.
Methods and results
We performed a biological physical proteinâprotein interaction network analysis to identify pathophysiological pathways distinguishing ischaemic from nonâischaemic HF. First, differentially expressed plasma protein biomarkers were identified in 1160 patients enrolled in the BIOSTATâCHF study, 715 of whom had ischaemic HF and 445 had nonâischaemic HF. Second, we constructed an enriched physical proteinâprotein interaction network, followed by a pathway overârepresentation analysis. Finally, we identified key network proteins. Data were validated in an independent HF cohort comprised of 765 ischaemic and 100 nonâischaemic HF patients. We found 21/92 proteins to be upâregulated and 2/92 downâregulated in ischaemic relative to nonâischaemic HF patients. An enriched network of 18 proteins that were specific for ischaemic heart disease yielded six pathways, which are related to inflammation, endothelial dysfunction superoxide production, coagulation, and atherosclerosis. We identified five key network proteins: acid phosphatase 5, epidermal growth factor receptor, insulinâlike growth factor binding proteinâ1, plasminogen activator urokinase receptor, and secreted phosphoprotein 1. Similar results were observed in the independent validation cohort.
Conclusions
Pathophysiological pathways distinguishing patients with ischaemic HF from those with nonâischaemic HF were related to inflammation, endothelial dysfunction superoxide production, coagulation, and atherosclerosis. The five key pathway proteins identified are potential treatment targets specifically for patients with ischaemic HF
Application of Machine Learning Techniques to Parameter Selection for Flight Risk Identification
In recent years, the use of data mining and machine learning techniques for safety analysis,
incident and accident investigation, and fault detection has gained traction among the aviation
community. Flight data collected from recording devices contains a large number of heterogeneous
parameters, sometimes reaching up to thousands on modern commercial aircraft. More
data is being collected continuously which adds to the ever-increasing pool of data available for
safety analysis. However, among the data collected, not all parameters are important from a
risk and safety analysis perspective. Similarly, in order to be useful for modern analysis techniques
such as machine learning, using thousands of parameters collected at a high frequency
might not be computationally tractable. As such, an intelligent and repeatable methodology to
select a reduced set of significant parameters is required to allow safety analysts to focus on the
right parameters for risk identification. In this paper, a step-by-step methodology is proposed
to down-select a reduced set of parameters that can be used for safety analysis. First, correlation
analysis is conducted to remove highly correlated, duplicate, or redundant parameters
from the data set. Second, a pre-processing step removes metadata and empty parameters.
This step also considers requirements imposed by regulatory bodies such as the Federal Aviation
Administration and subject matter experts to further trim the list of parameters. Third,
a clustering algorithm is used to group similar flights and identify abnormal operations and
anomalies. A retrospective analysis is conducted on the clusters to identify their characteristics
and impact on flight safety. Finally, analysis of variance techniques are used to identify which
parameters were significant in the formation of the clusters. Visualization dashboards were
created to analyze the cluster characteristics and parameter significance. This methodology is
employed on data from the approach phase of a representative single-aisle aircraft to demonstrate
its application and robustness across heterogeneous data sets. It is envisioned that this
methodology can be further extended to other phases of flight and aircraft
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