October 20, 2019

2985 words 15 mins read

Paper Group AWR 228

Paper Group AWR 228

Distributed Prioritized Experience Replay. Parallel Architecture and Hyperparameter Search via Successive Halving and Classification. Certified Robustness to Adversarial Examples with Differential Privacy. DATA Agent. Learning Symmetric and Low-energy Locomotion. Full deep neural network training on a pruned weight budget. Implementing Neural Turin …

Distributed Prioritized Experience Replay

Title Distributed Prioritized Experience Replay
Authors Dan Horgan, John Quan, David Budden, Gabriel Barth-Maron, Matteo Hessel, Hado van Hasselt, David Silver
Abstract We propose a distributed architecture for deep reinforcement learning at scale, that enables agents to learn effectively from orders of magnitude more data than previously possible. The algorithm decouples acting from learning: the actors interact with their own instances of the environment by selecting actions according to a shared neural network, and accumulate the resulting experience in a shared experience replay memory; the learner replays samples of experience and updates the neural network. The architecture relies on prioritized experience replay to focus only on the most significant data generated by the actors. Our architecture substantially improves the state of the art on the Arcade Learning Environment, achieving better final performance in a fraction of the wall-clock training time.
Tasks Atari Games
Published 2018-03-02
URL http://arxiv.org/abs/1803.00933v1
PDF http://arxiv.org/pdf/1803.00933v1.pdf
PWC https://paperswithcode.com/paper/distributed-prioritized-experience-replay
Repo https://github.com/Lyusungwon/apex_dqn_pytorch
Framework pytorch

Parallel Architecture and Hyperparameter Search via Successive Halving and Classification

Title Parallel Architecture and Hyperparameter Search via Successive Halving and Classification
Authors Manoj Kumar, George E. Dahl, Vijay Vasudevan, Mohammad Norouzi
Abstract We present a simple and powerful algorithm for parallel black box optimization called Successive Halving and Classification (SHAC). The algorithm operates in $K$ stages of parallel function evaluations and trains a cascade of binary classifiers to iteratively cull the undesirable regions of the search space. SHAC is easy to implement, requires no tuning of its own configuration parameters, is invariant to the scale of the objective function and can be built using any choice of binary classifier. We adopt tree-based classifiers within SHAC and achieve competitive performance against several strong baselines for optimizing synthetic functions, hyperparameters and architectures.
Tasks
Published 2018-05-25
URL http://arxiv.org/abs/1805.10255v1
PDF http://arxiv.org/pdf/1805.10255v1.pdf
PWC https://paperswithcode.com/paper/parallel-architecture-and-hyperparameter
Repo https://github.com/titu1994/pyshac
Framework tf

Certified Robustness to Adversarial Examples with Differential Privacy

Title Certified Robustness to Adversarial Examples with Differential Privacy
Authors Mathias Lecuyer, Vaggelis Atlidakis, Roxana Geambasu, Daniel Hsu, Suman Jana
Abstract Adversarial examples that fool machine learning models, particularly deep neural networks, have been a topic of intense research interest, with attacks and defenses being developed in a tight back-and-forth. Most past defenses are best effort and have been shown to be vulnerable to sophisticated attacks. Recently a set of certified defenses have been introduced, which provide guarantees of robustness to norm-bounded attacks, but they either do not scale to large datasets or are limited in the types of models they can support. This paper presents the first certified defense that both scales to large networks and datasets (such as Google’s Inception network for ImageNet) and applies broadly to arbitrary model types. Our defense, called PixelDP, is based on a novel connection between robustness against adversarial examples and differential privacy, a cryptographically-inspired formalism, that provides a rigorous, generic, and flexible foundation for defense.
Tasks
Published 2018-02-09
URL https://arxiv.org/abs/1802.03471v4
PDF https://arxiv.org/pdf/1802.03471v4.pdf
PWC https://paperswithcode.com/paper/certified-robustness-to-adversarial-examples
Repo https://github.com/locuslab/smoothing
Framework pytorch

DATA Agent

Title DATA Agent
Authors Michael Cerny Green, Gabriella A. B. Barros, Antonios Liapis, Julian Togelius
Abstract This paper introduces DATA Agent, a system which creates murder mystery adventures from open data. In the game, the player takes on the role of a detective tasked with finding the culprit of a murder. All characters, places, and items in DATA Agent games are generated using open data as source content. The paper discusses the general game design and user interface of DATA Agent, and provides details on the generative algorithms which transform linked data into different game objects. Findings from a user study with 30 participants playing through two games of DATA Agent show that the game is easy and fun to play, and that the mysteries it generates are straightforward to solve.
Tasks
Published 2018-09-28
URL https://arxiv.org/abs/1810.02251v1
PDF https://arxiv.org/pdf/1810.02251v1.pdf
PWC https://paperswithcode.com/paper/data-agent
Repo https://github.com/michaelbrave/Procedural-Generation-And-Generative-Systems-Resources
Framework none

Learning Symmetric and Low-energy Locomotion

Title Learning Symmetric and Low-energy Locomotion
Authors Wenhao Yu, Greg Turk, C. Karen Liu
Abstract Learning locomotion skills is a challenging problem. To generate realistic and smooth locomotion, existing methods use motion capture, finite state machines or morphology-specific knowledge to guide the motion generation algorithms. Deep reinforcement learning (DRL) is a promising approach for the automatic creation of locomotion control. Indeed, a standard benchmark for DRL is to automatically create a running controller for a biped character from a simple reward function. Although several different DRL algorithms can successfully create a running controller, the resulting motions usually look nothing like a real runner. This paper takes a minimalist learning approach to the locomotion problem, without the use of motion examples, finite state machines, or morphology-specific knowledge. We introduce two modifications to the DRL approach that, when used together, produce locomotion behaviors that are symmetric, low-energy, and much closer to that of a real person. First, we introduce a new term to the loss function (not the reward function) that encourages symmetric actions. Second, we introduce a new curriculum learning method that provides modulated physical assistance to help the character with left/right balance and forward movement. The algorithm automatically computes appropriate assistance to the character and gradually relaxes this assistance, so that eventually the character learns to move entirely without help. Because our method does not make use of motion capture data, it can be applied to a variety of character morphologies. We demonstrate locomotion controllers for the lower half of a biped, a full humanoid, a quadruped, and a hexapod. Our results show that learned policies are able to produce symmetric, low-energy gaits. In addition, speed-appropriate gait patterns emerge without any guidance from motion examples or contact planning.
Tasks Motion Capture
Published 2018-01-24
URL http://arxiv.org/abs/1801.08093v3
PDF http://arxiv.org/pdf/1801.08093v3.pdf
PWC https://paperswithcode.com/paper/learning-symmetric-and-low-energy-locomotion
Repo https://github.com/jyf588/lrle-rl-examples
Framework tf

Full deep neural network training on a pruned weight budget

Title Full deep neural network training on a pruned weight budget
Authors Maximilian Golub, Guy Lemieux, Mieszko Lis
Abstract We introduce a DNN training technique that learns only a fraction of the full parameter set without incurring an accuracy penalty. To do this, our algorithm constrains the total number of weights updated during backpropagation to those with the highest total gradients. The remaining weights are not tracked, and their initial value is regenerated at every access to avoid storing them in memory. This can dramatically reduce the number of off-chip memory accesses during both training and inference, a key component of the energy needs of DNN accelerators. By ensuring that the total weight diffusion remains close to that of baseline unpruned SGD, networks pruned using our technique are able to retain state-of-the-art accuracy across network architectures – including networks previously identified as difficult to compress, such as Densenet and WRN. With ResNet18 on ImageNet, we observe an 11.7$\times$ weight reduction with no accuracy loss, and up to 24.4$\times$ with a small accuracy impact.
Tasks
Published 2018-06-11
URL https://arxiv.org/abs/1806.06949v2
PDF https://arxiv.org/pdf/1806.06949v2.pdf
PWC https://paperswithcode.com/paper/dropback-continuous-pruning-during-training
Repo https://github.com/snownus/COOP
Framework none

Implementing Neural Turing Machines

Title Implementing Neural Turing Machines
Authors Mark Collier, Joeran Beel
Abstract Neural Turing Machines (NTMs) are an instance of Memory Augmented Neural Networks, a new class of recurrent neural networks which decouple computation from memory by introducing an external memory unit. NTMs have demonstrated superior performance over Long Short-Term Memory Cells in several sequence learning tasks. A number of open source implementations of NTMs exist but are unstable during training and/or fail to replicate the reported performance of NTMs. This paper presents the details of our successful implementation of a NTM. Our implementation learns to solve three sequential learning tasks from the original NTM paper. We find that the choice of memory contents initialization scheme is crucial in successfully implementing a NTM. Networks with memory contents initialized to small constant values converge on average 2 times faster than the next best memory contents initialization scheme.
Tasks
Published 2018-07-23
URL http://arxiv.org/abs/1807.08518v3
PDF http://arxiv.org/pdf/1807.08518v3.pdf
PWC https://paperswithcode.com/paper/implementing-neural-turing-machines
Repo https://github.com/MarkPKCollier/NeuralTuringMachine
Framework tf

Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actor

Title Soft Actor-Critic: Off-Policy Maximum Entropy Deep Reinforcement Learning with a Stochastic Actor
Authors Tuomas Haarnoja, Aurick Zhou, Pieter Abbeel, Sergey Levine
Abstract A platform for Applied Reinforcement Learning (Applied RL)
Tasks Continuous Control, Decision Making, Q-Learning
Published 2018-01-04
URL http://arxiv.org/abs/1801.01290v2
PDF http://arxiv.org/pdf/1801.01290v2.pdf
PWC https://paperswithcode.com/paper/soft-actor-critic-off-policy-maximum-entropy
Repo https://github.com/facebookresearch/Horizon
Framework pytorch

Learning a Representation Map for Robot Navigation using Deep Variational Autoencoder

Title Learning a Representation Map for Robot Navigation using Deep Variational Autoencoder
Authors Kaixin Hu, Peter O’Connor
Abstract The aim of this work is to use Variational Autoencoder (VAE) to learn a representation of an indoor environment that can be used for robot navigation. We use images extracted from a video, in which a camera takes a tour around a house, for training the VAE model with a 4 dimensional latent space. After the model is trained, each real frame has a corresponding representation point on manifold in the latent space, and each representation point has corresponding reconstructed image. For the navigation problem, we map the starting image and destination image to the latent space, then optimize a path on the learned manifold connecting the two points, and finally map the path back through decoder to a sequence of images. The ideal sequence of images should correspond to a route that is spatially continuous - i.e. neighbor images in the route should correspond to neighbor locations in physical space. Such a route could be used for navigation with computer vision techniques, i.e. a robot could follow the image sequence from starting location to destination in the environment step by step. We implement this algorithm, but find in our experimental results that the resulting route is not satisfactory. The route consist of several discontinuous image frames along the ideal routes, so that the route could not be followed by a robot with computer vision techniques in practice. In our evaluation, we propose two reasons for our failure to automatically find continuous routes: (1) The VAE tends to capture global structures, but discard the details; (2) the Euclidean similarity metric used for measuring continuity between house images is sub-optimal. For further work, we propose: trying other generative models like VAE-GANs which may be better at reconstructing the details to learn the representation map, and adjusting the similarity metric in the path selecting algorithm.
Tasks Robot Navigation
Published 2018-07-05
URL http://arxiv.org/abs/1807.02401v2
PDF http://arxiv.org/pdf/1807.02401v2.pdf
PWC https://paperswithcode.com/paper/learning-a-representation-map-for-robot
Repo https://github.com/augustkx/VAE_learning-a-representation-for-navigation
Framework none

Evolution of a Functionally Diverse Swarm via a Novel Decentralised Quality-Diversity Algorithm

Title Evolution of a Functionally Diverse Swarm via a Novel Decentralised Quality-Diversity Algorithm
Authors Emma Hart, Andreas S. W. Steyven, Ben Paechter
Abstract The presence of functional diversity within a group has been demonstrated to lead to greater robustness, higher performance and increased problem-solving ability in a broad range of studies that includes insect groups, human groups and swarm robotics. Evolving group diversity however has proved challenging within Evolutionary Robotics, requiring reproductive isolation and careful attention to population size and selection mechanisms. To tackle this issue, we introduce a novel, decentralised, variant of the MAP-Elites illumination algorithm which is hybridised with a well-known distributed evolutionary algorithm (mEDEA). The algorithm simultaneously evolves multiple diverse behaviours for multiple robots, with respect to a simple token-gathering task. Each robot in the swarm maintains a local archive defined by two pre-specified functional traits which is shared with robots it come into contact with. We investigate four different strategies for sharing, exploiting and combining local archives and compare results to mEDEA. Experimental results show that in contrast to previous claims, it is possible to evolve a functionally diverse swarm without geographical isolation, and that the new method outperforms mEDEA in terms of the diversity, coverage and precision of the evolved swarm.
Tasks
Published 2018-04-20
URL http://arxiv.org/abs/1804.07655v1
PDF http://arxiv.org/pdf/1804.07655v1.pdf
PWC https://paperswithcode.com/paper/evolution-of-a-functionally-diverse-swarm-via
Repo https://github.com/asteyven/EDQD-GECCO2018
Framework none

Neural Network-Hardware Co-design for Scalable RRAM-based BNN Accelerators

Title Neural Network-Hardware Co-design for Scalable RRAM-based BNN Accelerators
Authors Yulhwa Kim, Hyungjun Kim, Jae-Joon Kim
Abstract Recently, RRAM-based Binary Neural Network (BNN) hardware has been gaining interests as it requires 1-bit sense-amp only and eliminates the need for high-resolution ADC and DAC. However, RRAM-based BNN hardware still requires high-resolution ADC for partial sum calculation to implement large-scale neural network using multiple memory arrays. We propose a neural network-hardware co-design approach to split input to fit each split network on a RRAM array so that the reconstructed BNNs calculate 1-bit output neuron in each array. As a result, ADC can be completely eliminated from the design even for large-scale neural network. Simulation results show that the proposed network reconstruction and retraining recovers the inference accuracy of the original BNN. The accuracy loss of the proposed scheme in the CIFAR-10 testcase was less than 1.1% compared to the original network. The code for training and running proposed BNN models is available at: https://github.com/YulhwaKim/RRAMScalable_BNN.
Tasks
Published 2018-11-06
URL http://arxiv.org/abs/1811.02187v2
PDF http://arxiv.org/pdf/1811.02187v2.pdf
PWC https://paperswithcode.com/paper/neural-network-hardware-co-design-for
Repo https://github.com/YulhwaKim/RRAMScalable_BNN
Framework none

The committee machine: Computational to statistical gaps in learning a two-layers neural network

Title The committee machine: Computational to statistical gaps in learning a two-layers neural network
Authors Benjamin Aubin, Antoine Maillard, Jean Barbier, Florent Krzakala, Nicolas Macris, Lenka Zdeborová
Abstract Heuristic tools from statistical physics have been used in the past to locate the phase transitions and compute the optimal learning and generalization errors in the teacher-student scenario in multi-layer neural networks. In this contribution, we provide a rigorous justification of these approaches for a two-layers neural network model called the committee machine. We also introduce a version of the approximate message passing (AMP) algorithm for the committee machine that allows to perform optimal learning in polynomial time for a large set of parameters. We find that there are regimes in which a low generalization error is information-theoretically achievable while the AMP algorithm fails to deliver it, strongly suggesting that no efficient algorithm exists for those cases, and unveiling a large computational gap.
Tasks
Published 2018-06-14
URL https://arxiv.org/abs/1806.05451v2
PDF https://arxiv.org/pdf/1806.05451v2.pdf
PWC https://paperswithcode.com/paper/the-committee-machine-computational-to
Repo https://github.com/benjaminaubin/TheCommitteeMachine
Framework none

Treepedia 2.0: Applying Deep Learning for Large-scale Quantification of Urban Tree Cover

Title Treepedia 2.0: Applying Deep Learning for Large-scale Quantification of Urban Tree Cover
Authors Bill Yang Cai, Xiaojiang Li, Ian Seiferling, Carlo Ratti
Abstract Recent advances in deep learning have made it possible to quantify urban metrics at fine resolution, and over large extents using street-level images. Here, we focus on measuring urban tree cover using Google Street View (GSV) images. First, we provide a small-scale labelled validation dataset and propose standard metrics to compare the performance of automated estimations of street tree cover using GSV. We apply state-of-the-art deep learning models, and compare their performance to a previously established benchmark of an unsupervised method. Our training procedure for deep learning models is novel; we utilize the abundance of openly available and similarly labelled street-level image datasets to pre-train our model. We then perform additional training on a small training dataset consisting of GSV images. We find that deep learning models significantly outperform the unsupervised benchmark method. Our semantic segmentation model increased mean intersection-over-union (IoU) from 44.10% to 60.42% relative to the unsupervised method and our end-to-end model decreased Mean Absolute Error from 10.04% to 4.67%. We also employ a recently developed method called gradient-weighted class activation map (Grad-CAM) to interpret the features learned by the end-to-end model. This technique confirms that the end-to-end model has accurately learned to identify tree cover area as key features for predicting percentage tree cover. Our paper provides an example of applying advanced deep learning techniques on a large-scale, geo-tagged and image-based dataset to efficiently estimate important urban metrics. The results demonstrate that deep learning models are highly accurate, can be interpretable, and can also be efficient in terms of data-labelling effort and computational resources.
Tasks Semantic Segmentation
Published 2018-08-14
URL http://arxiv.org/abs/1808.04754v1
PDF http://arxiv.org/pdf/1808.04754v1.pdf
PWC https://paperswithcode.com/paper/treepedia-20-applying-deep-learning-for-large
Repo https://github.com/billcai/treepedia_dl_public
Framework tf

Post-Processing of Word Representations via Variance Normalization and Dynamic Embedding

Title Post-Processing of Word Representations via Variance Normalization and Dynamic Embedding
Authors Bin Wang, Fenxiao Chen, Angela Wang, C. -C. Jay Kuo
Abstract Although embedded vector representations of words offer impressive performance on many natural language processing (NLP) applications, the information of ordered input sequences is lost to some extent if only context-based samples are used in the training. For further performance improvement, two new post-processing techniques, called post-processing via variance normalization (PVN) and post-processing via dynamic embedding (PDE), are proposed in this work. The PVN method normalizes the variance of principal components of word vectors while the PDE method learns orthogonal latent variables from ordered input sequences. The PVN and the PDE methods can be integrated to achieve better performance. We apply these post-processing techniques to two popular word embedding methods (i.e., word2vec and GloVe) to yield their post-processed representations. Extensive experiments are conducted to demonstrate the effectiveness of the proposed post-processing techniques.
Tasks
Published 2018-08-20
URL http://arxiv.org/abs/1808.06305v3
PDF http://arxiv.org/pdf/1808.06305v3.pdf
PWC https://paperswithcode.com/paper/post-processing-of-word-representations-via
Repo https://github.com/BinWang28/PVN-Post-Processing-of-word-representation-via-variance-normalization
Framework none

Text-to-Image-to-Text Translation using Cycle Consistent Adversarial Networks

Title Text-to-Image-to-Text Translation using Cycle Consistent Adversarial Networks
Authors Satya Krishna Gorti, Jeremy Ma
Abstract Text-to-Image translation has been an active area of research in the recent past. The ability for a network to learn the meaning of a sentence and generate an accurate image that depicts the sentence shows ability of the model to think more like humans. Popular methods on text to image translation make use of Generative Adversarial Networks (GANs) to generate high quality images based on text input, but the generated images don’t always reflect the meaning of the sentence given to the model as input. We address this issue by using a captioning network to caption on generated images and exploit the distance between ground truth captions and generated captions to improve the network further. We show extensive comparisons between our method and existing methods.
Tasks
Published 2018-08-14
URL http://arxiv.org/abs/1808.04538v1
PDF http://arxiv.org/pdf/1808.04538v1.pdf
PWC https://paperswithcode.com/paper/text-to-image-to-text-translation-using-cycle
Repo https://github.com/CSC2548/text2image2textGAN
Framework pytorch
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