Deep Learning
TensorFlow review: The best deep learning library gets better
If you looked at TensorFlow as a deep learning framework last year and decided that it was too hard or too immature to use, it might be time to give it another look. Since I reviewed TensorFlow r0.10 in October 2016, Google's open source framework for deep learning has become more mature, implemented more algorithms and deployment options, and become easier to program. TensorFlow is now up to version r1.4.1 (stable version and web documentation), r1.5 (release candidate), and pre-release r1.6 (master branch and daily builds). The TensorFlow project has been quite active. As a crude measure, the TensorFlow repository on GitHub currently has about 27 thousand commits, 85 thousand stars, and 42 thousand forks.
As China Marches Forward on A.I., the White House Is Silent
But six months after China seemed to mimic that Obama-era road map, A.I. experts in industry and academia in the United States say that the Trump White House has done little to follow through on the previous administration's economic call to arms. "We are still waiting on the White House to provide some direction" on how to respond to the competition, said Tim Hwang, who worked on A.I. policy at Google and is now the director of the Ethics and Governance of AI Initiative, a new organization created by the LinkedIn founder Reid Hoffman and others to fund ethical research in artificial intelligence. China's embrace of A.I. comes at a crucial time in the development of the technology and just as the lead long enjoyed by the United States has started to dwindle. For decades, artificial intelligence was more fiction than science. In the past few years, however, dramatic improvements have prompted some of the biggest companies in Silicon Valley and Detroit -- and China -- to invest billions on everything from self-driving cars to home appliances that can have a conversation with a human.
Artificial Intelligence (AI) Business Directory โ Adaptive Toolbox
This is a list of key companies worldwide with products, services, and applications in the fields related to the Artificial Intelligence (AI) & Optimization. Feel free to submit a listing and maintain it for your own business. The listing service is free. Any additional questions and comments should be submitted here. Typical AI fields include, but not limited to: Machine Learning (ML), Deep Learning, Cognitive Computing, Natural Language Processing (NLP), Computer Vision, Pattern Recognition, Autonomous Agents and Multi-Agent Systems, Automated Planning and Scheduling, Robotics, Predictive Analytics, etc.
Matrix Completion via Factorizing Polynomials
Shah, Vatsal, Rao, Nikhil, Ding, Weicong
Predicting unobserved entries of a partially observed matrix has found wide applicability in several areas, such as recommender systems, computational biology, and computer vision. Many scalable methods with rigorous theoretical guarantees have been developed for algorithms where the matrix is factored into low-rank components, and embeddings are learned for the row and column entities. While there has been recent research on incorporating explicit side information in the low-rank matrix factorization setting, often implicit information can be gleaned from the data, via higher-order interactions among entities. Such implicit information is especially useful in cases where the data is very sparse, as is often the case in real-world datasets. In this paper, we design a method to learn embeddings in the context of recommendation systems, using the observation that higher powers of a graph transition probability matrix encode the probability that a random walker will hit that node in a given number of steps. We develop a coordinate descent algorithm to solve the resulting optimization, that makes explicit computation of the higher order powers of the matrix redundant, preserving sparsity and making computations efficient. Experiments on several datasets show that our method, that can use higher order information, outperforms methods that only use explicitly available side information, those that use only second-order implicit information and in some cases, methods based on deep neural networks as well.
Continuous-Time Flows for Efficient Inference and Density Estimation
Chen, Changyou, Li, Chunyuan, Chen, Liqun, Wang, Wenlin, Pu, Yunchen, Carin, Lawrence
Two fundamental problems in unsupervised learning are efficient inference for latent-variable models and robust density estimation based on large amounts of unlabeled data. Algorithms for the two tasks, such as normalizing flows and generative adversarial networks (GANs), are often developed independently. In this paper, we propose the concept of {\em continuous-time flows} (CTFs), a family of diffusion-based methods that are able to asymptotically approach a target distribution. Distinct from normalizing flows and GANs, CTFs can be adopted to achieve the above two goals in one framework, with theoretical guarantees. Our framework includes distilling knowledge from a CTF for efficient inference, and learning an explicit energy-based distribution with CTFs for density estimation. Both tasks rely on a new technique for distribution matching within amortized learning. Experiments on various tasks demonstrate promising performance of the proposed CTF framework, compared to related techniques.
Edge Attention-based Multi-Relational Graph Convolutional Networks
Shang, Chao, Liu, Qinqing, Chen, Ko-Shin, Sun, Jiangwen, Lu, Jin, Yi, Jinfeng, Bi, Jinbo
Graph convolutional network (GCN) is generalization of convolutional neural network (CNN) to work with arbitrarily structured graphs. A binary adjacency matrix is commonly used in training a GCN. Recently, the attention mechanism allows the network to learn a dynamic and adaptive aggregation of the neighborhood. We propose a new GCN model on the graphs where edges are characterized in multiple views or precisely in terms of multiple relationships. For instance, in chemical graph theory, compound structures are often represented by the hydrogen-depleted molecular graph where nodes correspond to atoms and edges correspond to chemical bonds. Multiple attributes can be important to characterize chemical bonds, such as atom pair (the types of atoms that a bond connects), aromaticity, and whether a bond is in a ring. The different attributes lead to different graph representations for the same molecule. There is growing interests in both chemistry and machine learning fields to directly learn molecular properties of compounds from the molecular graph, instead of from fingerprints predefined by chemists. The proposed GCN model, which we call edge attention-based multi-relational GCN (EAGCN), jointly learns attention weights and node features in graph convolution. For each bond attribute, a real-valued attention matrix is used to replace the binary adjacency matrix. By designing a dictionary for the edge attention, and forming the attention matrix of each molecule by looking up the dictionary, the EAGCN exploits correspondence between bonds in different molecules. The prediction of compound properties is based on the aggregated node features, which is independent of the varying molecule (graph) size. We demonstrate the efficacy of the EAGCN on multiple chemical datasets: Tox21, HIV, Freesolv, and Lipophilicity, and interpret the resultant attention weights.
DVAE++: Discrete Variational Autoencoders with Overlapping Transformations
Vahdat, Arash, Macready, William G., Bian, Zhengbing, Khoshaman, Amir
Training of discrete latent variable models remains challenging because passing gradient information through discrete units is difficult. We propose a new class of smoothing transformations based on a mixture of two overlapping distributions, and show that the proposed transformation can be used for training binary latent models with either directed or undirected priors. We derive a new variational bound to efficiently train with Boltzmann machine priors. Using this bound, we develop DVAE++, a generative model with a global discrete prior and a hierarchy of convolutional continuous variables. Experiments on several benchmarks show that overlapping transformations outperform other recent continuous relaxations of discrete latent variables including Gumbel-Softmax (Maddison et al., 2016; Jang et al., 2016), and discrete variational autoencoders (Rolfe 2016).
Quantifying Uncertainty in Discrete-Continuous and Skewed Data with Bayesian Deep Learning
Vandal, Thomas, Kodra, Evan, Dy, Jennifer, Ganguly, Sangram, Nemani, Ramakrishna, Ganguly, Auroop R.
Deep Learning (DL) methods have been transforming computer vision with innovative adaptations to other domains including climate change. For DL to pervade Science and Engineering (S\&E) applications where risk management is a core component, well-characterized uncertainty estimates must accompany predictions. However, S\&E observations and model-simulations often follow heavily skewed distributions and are not well modeled with DL approaches, since they usually optimize a Gaussian, or Euclidean, likelihood loss. Recent developments in Bayesian Deep Learning (BDL), which attempts to capture uncertainties from noisy observations, aleatoric, and from unknown model parameters, epistemic, provide us a foundation. Here we present a discrete-continuous BDL model with Gaussian and lognormal likelihoods for uncertainty quantification (UQ). We demonstrate the approach by developing UQ estimates on "DeepSD", a super-resolution based DL model for Statistical Downscaling (SD) in climate applied to precipitation, which follows an extremely skewed distribution. We find that the discrete-continuous models outperform a basic Gaussian distribution in terms of predictive accuracy and uncertainty calibration. Furthermore, we find that the lognormal distribution, which can handle skewed distributions, produces quality uncertainty estimates at the extremes. Such results may be important across S\&E, as well as other domains such as finance and economics, where extremes are often of significant interest. Furthermore, to our knowledge, this is the first UQ model in SD where both aleatoric and epistemic uncertainties are characterized.
Neural Relational Inference for Interacting Systems
Kipf, Thomas, Fetaya, Ethan, Wang, Kuan-Chieh, Welling, Max, Zemel, Richard
Interacting systems are prevalent in nature, from dynamical systems in physics to complex societal dynamics. The interplay of components can give rise to complex behavior, which can often be explained using a simple model of the system's constituent parts. In this work, we introduce the neural relational inference (NRI) model: an unsupervised model that learns to infer interactions while simultaneously learning the dynamics purely from observational data. Our model takes the form of a variational auto-encoder, in which the latent code represents the underlying interaction graph and the reconstruction is based on graph neural networks. In experiments on simulated physical systems, we show that our NRI model can accurately recover ground-truth interactions in an unsupervised manner. We further demonstrate that we can find an interpretable structure and predict complex dynamics in real motion capture and sports tracking data.
Barista - a Graphical Tool for Designing and Training Deep Neural Networks
Klemm, Soeren, Scherzinger, Aaron, Drees, Dominik, Jiang, Xiaoyi
In recent years, the importance of deep learning has significantly increased in pattern recognition, computer vision, and artificial intelligence research, as well as in industry. However, despite the existence of multiple deep learning frameworks, there is a lack of comprehensible and easy-to-use high-level tools for the design, training, and testing of deep neural networks (DNNs). In this paper, we introduce Barista, an open-source graphical high-level interface for the Caffe deep learning framework. While Caffe is one of the most popular frameworks for training DNNs, editing prototext files in order to specify the net architecture and hyper parameters can become a cumbersome and error-prone task. Instead, Barista offers a fully graphical user interface with a graph-based net topology editor and provides an end-to-end training facility for DNNs, which allows researchers to focus on solving their problems without having to write code, edit text files, or manually parse logged data.