Generative AI
Dynamic Action Selection in OpenAI Using Spiking Neural Networks
Peters, Chad (Carleton University) | Stewart, Terrence C. (University of Waterloo) | West, Robert L. (Carleton University) | Esfandiari, Babak
Modelling biologically-plausible neural structures for intelligent agents presents a unique challenge when operating in real-time domains. Neurons in our brains have different response properties, firing rates, and propagation lengths, creating noise that cannot be reliably decoded. This research explores the strengths and limitations of LIF spiking neuron ensembles for application in OpenAI virtual environments. Topics discussed include how we represent arbitrary environmental signals from multiple senses, choosing between equally viable actions in a given scenario, and how one can create a generic model that can learn and operate in a verity of situations.
A Deep Reinforcement Learn-Based FIFA Agent with Naive State Representations and Portable Connection Interfaces
Faria, Matheus Prado Prandini (Federal University of Uberlรขndi) | Julia, Rita Maria Silva (Federal University of Uberlรขndi) | Tomaz, Lรญdia Bononi Paiva (Federal University of Triรขngulo Mineiroi)
Video games have proved to be a very defying laboratory to study machine-learning techniques, such as Deep Reinforcement Learning (DRL) algorithms. This paper presents a new approach for a DRL-based agent trained through Deep Q-Network (DQN) technique to perform free kicks in FIFA 18 game. The main motivation for choosing this case study is the fact that, like in many situations of the real life, FIFA represents a stochastic environment. Coping with this task, the main contributions of the present paper consist on: inspired on the OpenAI Gym and on the OpenAI Universe platforms, implementing a new user-friendly interface (in terms of portability and use simplicity) to connect the learning module with the 3D FIFA's game environment; implementing a DRL-based agent for free kicks in FIFA that uses two distinct data representations retrieved from lower cost computational procedures. The results were validated through two evaluative parameters: score of well succeed kicks and training time.
Modelling urban networks using Variational Autoencoders
Kempinska, Kira, Murcio, Roberto
A long-standing question for urban and regional planners pertains to the ability to describe urban patterns quantitatively. Cities' transport infrastructure, particularly street networks, provides an invaluable source of information about the urban patterns generated by peoples' movements and their interactions. With the increasing availability of street network datasets and the advancements in deep learning methods, we are presented with an unprecedented opportunity to push the frontiers of urban modelling towards more data-driven and accurate models of urban forms. In this study, we present our initial work on applying deep generative models to urban street network data to create spatially explicit urban models. We based our work on Variational Autoencoders (VAEs) which are deep generative models that have recently gained their popularity due to the ability to generate realistic images. Initial results show that VAEs are capable of capturing key high-level urban network metrics using low-dimensional vectors and generating new urban forms of complexity matching the cities captured in the street network data.
Ian Goodfellow: Generative Adversarial Networks (GANs) MIT Artificial Intelligence (AI) Podcast
Ian Goodfellow is an author of the popular textbook on deep learning (simply titled "Deep Learning"). He invented Generative Adversarial Networks (GANs) and with his 2014 paper is responsible for launching the incredible growth of research on GANs. He got his BS and MS at Stanford, his PhD at University of Montreal with Yoshua Bengio and Aaron Courville. He held several research positions including at OpenAI, Google Brain, and now at Apple as director of machine learning. This recording happened while Ian was still at Google Brain.
Deep Generative Models for Sparse, High-dimensional, and Overdispersed Discrete Data
Zhao, He, Rai, Piyush, Du, Lan, Buntine, Wray, Zhou, Mingyuan
Many applications, such as text modelling, high-throughput sequencing, and recommender systems, require analysing sparse, high-dimensional, and overdispersed discrete (count/binary) data. With the ability of handling high-dimensional and sparse discrete data, models based on probabilistic matrix factorisation and latent factor analysis have enjoyed great success in modeling such data. Of particular interest among these are hierarchical Bayesian count/binary matrix factorisation models and nonlinear latent variable models based on deep neural networks, such as recently proposed variational autoencoders for discrete data. However, unlike the extensive research on sparsity and high-dimensionality, another important phenomenon, overdispersion, which large-scale discrete data exhibit, is relatively less studied. It can be shown that most existing latent factor models do not capture overdispersion in discrete data properly due to their ineffectiveness of modelling self- and cross-excitation (e.g., word burstiness in text), which may lead to inferior modelling performance. In this paper, we provide an in-depth analysis on how self- and cross-excitation are modelled in existing models and propose a novel variational autoencoder framework, which is able to explicitly capture self-excitation and also better model cross-excitation. Our model construction is originally designed for count-valued observations with the negative-binomial data distribution (and an equivalent representation with the Dirichlet-multinomial distribution) and it also extends seamlessly to binary-valued observations via a link function to the Bernoulli distribution. To demonstrate the effectiveness of our framework, we conduct extensive experiments on both large-scale bag-of-words corpora and collaborative filtering datasets, where the proposed models achieve state-of-the-art results.
A Deep Generative Model for Graph Layout
As different layouts can characterize different aspects of the same graph, finding a "good" layout of a graph is an important task for graph visualization. In practice, users often visualize a graph in multiple layouts by using different methods and varying parameter settings until they find a layout that best suits the purpose of the visualization. However, this trial-and-error process is often haphazard and time-consuming. To provide users with an intuitive way to navigate the layout design space, we present a technique to systematically visualize a graph in diverse layouts using deep generative models. We design an encoder-decoder architecture to learn a model from a collection of example layouts, where the encoder represents training examples in a latent space and the decoder produces layouts from the latent space. In particular, we train the model to construct a two-dimensional latent space for users to easily explore and generate various layouts. We demonstrate our approach through quantitative and qualitative evaluations of the generated layouts. The results of our evaluations show that our model is capable of learning and generalizing abstract concepts of graph layouts, not just memorizing the training examples. In summary, this paper presents a fundamentally new approach to graph visualization where a machine learning model learns to visualize a graph from examples without manually-defined heuristics.
AI defeated a top-tier 'Dota 2' esports team
So much for the best Dota 2 players having the skill to fend off cutting-edge AI. OpenAI Five has beaten five players from OG, the veteran team that won Valve's 2018 International, in a best-of-three exhibition match. The Verge noted that the deep learning system thrived by relying on aggressive and unconventional methods, including instant revivals for heroes in the early stages, and picking valuable heroes. While OG put up a fight (the first round lasted over 30 minutes), it couldn't hold out. OpenAI also used the exhibition to show that Five could play alongside human players and learn from their play styles.
Deep Generative Models for Reject Inference in Credit Scoring
Mancisidor, Rogelio A., Kampffmeyer, Michael, Aas, Kjersti, Jenssen, Robert
Credit scoring models based on accepted applications may be biased and their consequences can have a statistical and economic impact. Reject inference is the process of attempting to infer the creditworthiness status of the rejected applications. In this research, we use deep generative models to develop two new semi-supervised Bayesian models for reject inference in credit scoring, in which we model the data generating process to be dependent on a Gaussian mixture. The goal is to improve the classification accuracy in credit scoring models by adding reject applications. Our proposed models infer the unknown creditworthiness of the rejected applications by exact enumeration of the two possible outcomes of the loan (default or non-default). The efficient stochastic gradient optimization technique used in deep generative models makes our models suitable for large data sets. Finally, the experiments in this research show that our proposed models perform better than classical and alternative machine learning models for reject inference in credit scoring.
What I learned using GPT-2 to write a novel
On February the 14th 2019 Open AI posted their peculiar love-letter to the AI community. They shared a 21-minute long blog talking about their new language model named GPT-2, examples of the text it had generated, and a slight warning. The blog ends with a series of possible policy implications and a release strategy. While we have grown accustomed to OpenAI sharing their full code bases alongside announcements, OpenAI is committed to making AI safe. On this occasion, releasing the full code was deemed unsafe, citing concerns around impersonation, misleading news, fake content, and spam/phishing attacks.