Oceania
Temporal Convolutional Networks and Dynamic Time Warping can Drastically Improve the Early Prediction of Sepsis
Moor, Michael, Horn, Max, Rieck, Bastian, Roqueiro, Damian, Borgwardt, Karsten
Motivation: Sepsis is a life-threatening host response to infection associated with high mortality, morbidity and health costs. Its management is highly time-sensitive since each hour of delayed treatment increases mortality due to irreversible organ damage. Meanwhile, despite decades of clinical research robust biomarkers for sepsis are missing. Therefore, detecting sepsis early by utilizing the affluence of high-resolution intensive care records has become a challenging machine learning problem. Recent advances in deep learning and data mining promise a powerful set of tools to efficiently address this task. Results: This paper proposes two approaches for the early detection of sepsis: a new deep learning model (MGP-TCN) and a data mining model (DTW-KNN). MGP-TCN employs a temporal convolutional network as embedded in a Multitask Gaussian Process Adapter framework, making it directly applicable to irregularly spaced time series data. Our DTW-KNN is an ensemble approach that employs dynamic time warping. We then frame the timely detection of sepsis as a supervised time series classification task. For this, we derive the most recent sepsis definition in an hourly resolution to provide the first fully accessible early sepsis detection environment. Seven hours before sepsis onset, our methods MGP-TCN/DTW-KNN improve area under the precision--recall curve from 0.25 to 0.35/0.40 over the state of the art. This demonstrates that they are well-suited for detecting sepsis in the crucial earlier stages when management is most effective.
Autonomous drones that can 'see' and fly intelligently
Drones have been given'eyes' and a new algorithm to help them fly intelligently, reaching their target position when GPS is not available. Dr. Jiefei Wang, a researcher from UNSW Canberra Trusted Autonomy Group, used an Xbox Kinect sensor as an input camera to help drones'see' their environment. Jiefei developed algorithms to process the video footage image by image, to help the drones know their own speed, motion, and to detect obstacles so they can reach their target position--a completely autonomous system. "Depth information is crucial for locating objects," Jiefei says. "Human beings can use one eye to see the world but need two eyes to locate. For example, try closing one eye, then point your index fingers towards each other and bring them together. Most people will find this difficult."
DeepIrisNet2: Learning Deep-IrisCodes from Scratch for Segmentation-Robust Visible Wavelength and Near Infrared Iris Recognition
Gangwar, Abhishek, Joshi, Akanksha, Joshi, Padmaja, Raghavendra, R.
We first, introduce a deep learning based framework named as DeepIrisNet2 for visible spectrum and NIR Iris representation. The framework can work without classical iris normalization step or very accurate iris segmentation; allowing to work under non-ideal situation. The framework contains spatial transformer layers to handle deformation and supervision branches after certain intermediate layers to mitigate overfitting. In addition, we present a dual CNN iris segmentation pipeline comprising of a iris/pupil bounding boxes detection network and a semantic pixel-wise segmentation network. Furthermore, to get compact templates, we present a strategy to generate binary iris codes using DeepIrisNet2. Since, no ground truth dataset are available for CNN training for iris segmentation, We build large scale hand labeled datasets and make them public; i) iris, pupil bounding boxes, ii) labeled iris texture. The networks are evaluated on challenging ND-IRIS-0405, UBIRIS.v2, MICHE-I, and CASIA v4 Interval datasets. Proposed approach significantly improves the state-of-the-art and achieve outstanding performance surpassing all previous methods.
Fast Hyperparameter Tuning using Bayesian Optimization with Directional Derivatives
Joy, Tinu Theckel, Rana, Santu, Gupta, Sunil, Venkatesh, Svetha
In this paper we develop a Bayesian optimization based hyperparameter tuning framework inspired by statistical learning theory for classifiers. We utilize two key facts from PAC learning theory; the generalization bound will be higher for a small subset of data compared to the whole, and the highest accuracy for a small subset of data can be achieved with a simple model. We initially tune the hyperparameters on a small subset of training data using Bayesian optimization. While tuning the hyperparameters on the whole training data, we leverage the insights from the learning theory to seek more complex models. We realize this by using directional derivative signs strategically placed in the hyperparameter search space to seek a more complex model than the one obtained with small data. We demonstrate the performance of our method on the tasks of tuning the hyperparameters of several machine learning algorithms.
Tsallis Reinforcement Learning: A Unified Framework for Maximum Entropy Reinforcement Learning
Lee, Kyungjae, Kim, Sungyub, Lim, Sungbin, Choi, Sungjoon, Oh, Songhwai
In this paper, we present a new class of Markov decision processes (MDPs), called Tsallis MDPs, with Tsallis entropy maximization, which generalizes existing maximum entropy reinforcement learning (RL). A Tsallis MDP provides a unified framework for the original RL problem and RL with various types of entropy, including the well-known standard Shannon-Gibbs (SG) entropy, using an additional real-valued parameter, called an entropic index. By controlling the entropic index, we can generate various types of entropy, including the SG entropy, and a different entropy results in a different class of the optimal policy in Tsallis MDPs. We also provide a full mathematical analysis of Tsallis MDPs, including the optimality condition, performance error bounds, and convergence. Our theoretical result enables us to use any positive entropic index in RL. To handle complex and large-scale problems, we propose a model-free actor-critic RL method using Tsallis entropy maximization. We evaluate the regularization effect of the Tsallis entropy with various values of entropic indices and show that the entropic index controls the exploration tendency of the proposed method. For a different type of RL problems, we find that a different value of the entropic index is desirable. The proposed method is evaluated using the MuJoCo simulator and achieves the state-of-the-art performance.
Latent Space Cartography: Generalised Metric-Inspired Measures and Measure-Based Transformations for Generative Models
Frenzel, Max F., Teleaga, Bogdan, Ushio, Asahi
Deep generative models are universal tools for learning data distributions on high dimensional data spaces via a mapping to lower dimensional latent spaces. We provide a study of latent space geometries and extend and build upon previous results on Riemannian metrics. We show how a class of heuristic measures gives more flexibility in finding meaningful, problem-specific distances, and how it can be applied to diverse generator types such as autoregressive generators commonly used in e.g. language and other sequence modeling. We further demonstrate how a diffusion-inspired transformation previously studied in cartography can be used to smooth out latent spaces, stretching them according to a chosen measure. In addition to providing more meaningful distances directly in latent space, this also provides a unique tool for novel kinds of data visualizations. We believe that the proposed methods can be a valuable tool for studying the structure of latent spaces and learned data distributions of generative models.
Deep Reinforcement Learning for Multi-Agent Systems: A Review of Challenges, Solutions and Applications
Nguyen, Thanh Thi, Nguyen, Ngoc Duy, Nahavandi, Saeid
Reinforcement learning (RL) algorithms have been around for decades and employed to solve various sequential decision-making problems. These algorithms however have faced great challenges when dealing with high-dimensional environments. The recent development of deep learning has enabled RL methods to drive optimal policies for sophisticated and capable agents, which can perform efficiently in these challenging environments. This paper addresses an important aspect of deep RL related to situations that require multiple agents to communicate and cooperate to solve complex tasks. A survey of different approaches to problems related to multi-agent deep RL (MADRL) is presented, including non-stationarity, partial observability, continuous state and action spaces, multi-agent training schemes, multi-agent transfer learning. The merits and demerits of the reviewed methods will be analyzed and discussed, with their corresponding applications explored. It is envisaged that this review provides insights about various MADRL methods and can lead to future development of more robust and highly useful multi-agent learning methods for solving real-world problems.
iFair: Learning Individually Fair Data Representations for Algorithmic Decision Making
Lahoti, Preethi, Gummadi, Krishna P., Weikum, Gerhard
People are rated and ranked, towards algorithmic decision making in an increasing number of applications, typically based on machine learning. Research on how to incorporate fairness into such tasks has prevalently pursued the paradigm of group fairness: giving adequate success rates to specifically protected groups. In contrast, the alternative paradigm of individual fairness has received relatively little attention, and this paper advances this less explored direction. The paper introduces a method for probabilistically mapping user records into a low-rank representation that reconciles individual fairness and the utility of classifiers and rankings in downstream applications. Our notion of individual fairness requires that users who are similar in all task-relevant attributes such as job qualification, and disregarding all potentially discriminating attributes such as gender, should have similar outcomes. We demonstrate the versatility of our method by applying it to classification and learning-to-rank tasks on a variety of real-world datasets. Our experiments show substantial improvements over the best prior work for this setting.
Consultation Human Rights and Technology
The Australian Human Rights Commission is conducting a project on Human Rights and New Technology (the Project). As part of the Project, the Commission and the World Economic Forum are working together to explore models of governance and leadership on artificial intelligence (AI) in Australia. This White Paper has been produced to support a consultation process that aims to identify how Australia can simultaneously foster innovation and protect human rights – as we see unprecedented growth in new technologies, such as AI. The White Paper complements the broader issues raised in the Commission's Human Rights and Technology Issues Paper. The consultation conducted on the Issues Paper and White Paper will inform the Commission's proposals for reform, to be released in mid-2019. The White Paper asks whether Australia needs an organisation to take a central role in promoting responsible innovation in AI and related technology and, if so, what that organisation could look like.
A Generalized Framework for Population Based Training
Li, Ang, Spyra, Ola, Perel, Sagi, Dalibard, Valentin, Jaderberg, Max, Gu, Chenjie, Budden, David, Harley, Tim, Gupta, Pramod
Previous PBT implementations have been synchronized glass-box systems. We propose a general, black-box PBT framework that distributes many asynchronous "trials" (a small number of training steps with warm-starting) across a cluster, coordinated by the PBT controller. The black-box design does not make assumptions on model architectures, loss functions Figure 1: Black-box Service for Population Based Training or training procedures. Our system supports dynamic hyperparameter based on a Worker-Controller framework. Each solid blue schedules to optimize both differentiable and non-differentiable circle represents a training trial. A black arrow represents a metrics. We apply our system to train a state-of-the-art WaveNet trial dependency (usually for warm-starting the model from generative model for human voice synthesis. We show that our PBT a parent's checkpoint) and a gray arrow represents an unselected system achieves better accuracy and faster convergence compared parent trial which loses in a tournament and fails to existing methods, given the same computational resource.