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EEG-based Drowsiness Estimation for Driving Safety using Deep Q-Learning
Ming, Yurui, Wu, Dongrui, Wang, Yu-Kai, Shi, Yuhui, Lin, Chin-Teng
Fatigue is the most vital factor of road fatalities and one manifestation of fatigue during driving is drowsiness . In this paper, we propose using deep Q - learning to analyze an electroencephalogram (EEG) dataset captured during a simulated endurance drivi ng test . By measur ing the correlation between drowsiness and driving performance, t h is experiment represents an important brain - computer interface (BCI) paradigm especially from an application perspective. We adapt the terminologies in the driving test to fit the reinforcement learning framework, thus formulate the drowsiness estimation problem as an optimization of a Q - learning task . B y referring to the latest deep Q - Learning technologies and attending to the characteristics of EEG data, we tailor a deep Q - network for action proposition that can indirectly estimate drowsiness . Our results show that the trained model can trace the variations of mind state in a satisfactory way against the testing EEG data, which demonstrates the feasibility and practicab ilit y of this new computation paradigm . We also show that our method outperforms the supervised learning counterpart and is superior for real applications. To the best of our knowledge, we are the first to introduce the deep reinforcement learning method to th is BCI scenario, and our method can be potentially generalized to other BCI cases . Fatigue is regarded as the most severe factor causing road fatalities [1] . To understand the correlation between fatigue and driving performance, both from theory to practice, is of persistent interest for researchers.
Convolutional Networks with Dense Connectivity
Huang, Gao, Liu, Zhuang, Pleiss, Geoff, van der Maaten, Laurens, Weinberger, Kilian Q.
Recent work has shown that convolutional networks can be substantially deeper, more accurate, and efficient to train if they contain shorter connections between layers close to the input and those close to the output. In this paper, we embrace this observation and introduce the Dense Convolutional Network (DenseNet), which connects each layer to every other layer in a feed-forward fashion.Whereas traditional convolutional networks with L layers have L connections - one between each layer and its subsequent layer - our network has L(L+1)/2 direct connections. For each layer, the feature-maps of all preceding layers are used as inputs, and its own feature-maps are used as inputs into all subsequent layers. DenseNets have several compelling advantages: they alleviate the vanishing-gradient problem, encourage feature reuse and substantially improve parameter efficiency. We evaluate our proposed architecture on four highly competitive object recognition benchmark tasks (CIFAR-10, CIFAR-100, SVHN, and ImageNet). DenseNets obtain significant improvements over the state-of-the-art on most of them, whilst requiring less parameters and computation to achieve high performance.
MACER: Attack-free and Scalable Robust Training via Maximizing Certified Radius
Zhai, Runtian, Dan, Chen, He, Di, Zhang, Huan, Gong, Boqing, Ravikumar, Pradeep, Hsieh, Cho-Jui, Wang, Liwei
Adversarial training is one of the most popular ways to learn robust models but is usually attack-dependent and time costly. In this paper, we propose the MACER algorithm, which learns robust models without using adversarial training but performs better than all existing provable l2-defenses. Recent work shows that randomized smoothing can be used to provide a certified l2 radius to smoothed classifiers, and our algorithm trains provably robust smoothed classifiers via MAximizing the CErtified Radius (MACER). The attack-free characteristic makes MACER faster to train and easier to optimize. In our experiments, we show that our method can be applied to modern deep neural networks on a wide range of datasets, including Cifar-10, ImageNet, MNIST, and SVHN. For all tasks, MACER spends less training time than state-of-the-art adversarial training algorithms, and the learned models achieve larger average certified radius.
PaRoT: A Practical Framework for Robust Deep Neural Network Training
Ayers, Edward, Eiras, Francisco, Hawasly, Majd, Whiteside, Iain
Deep Neural Networks (DNNs) are finding important applications in safety-critical systems such as Autonomous Vehicles (AVs), where perceiving the environment correctly and robustly is necessary for safe operation. Raising unique challenges for assurance due to their black-box nature, DNNs pose a fundamental problem for regulatory acceptance of these types of systems. Robust training --- training to minimize excessive sensitivity to small changes in input --- has emerged as one promising technique to address this challenge. However, existing robust training tools are inconvenient to use or apply to existing codebases and models: they typically only support a small subset of model elements and require users to extensively rewrite the training code. In this paper we introduce a novel framework, PaRoT, developed on the popular TensorFlow platform, that greatly reduces the barrier to entry. Our framework enables robust training to be performed on arbitrary DNNs without any rewrites to the model. We demonstrate that our framework's performance is comparable to prior art, and exemplify its ease of use on off-the-shelf, trained models and on a real-world industrial application: training a robust traffic light detection network.
Backtracking Gradient Descent allowing unbounded learning rates
In unconstrained optimisation on an Euclidean space, to prove convergence in Gradient Descent processes (GD) $x_{n+1}=x_n-\delta _n \nabla f(x_n)$ it usually is required that the learning rates $\delta _n$'s are bounded: $\delta _n\leq \delta $ for some positive $\delta $. Under this assumption, if the sequence $x_n$ converges to a critical point $z$, then with large values of $n$ the update will be small because $||x_{n+1}-x_n||\lesssim ||\nabla f(x_n)||$. This may also force the sequence to converge to a bad minimum. If we can allow, at least theoretically, that the learning rates $\delta _n$'s are not bounded, then we may have better convergence to better minima. A previous joint paper by the author showed convergence for the usual version of Backtracking GD under very general assumptions on the cost function $f$. In this paper, we allow the learning rates $\delta _n$ to be unbounded, in the sense that there is a function $h:(0,\infty)\rightarrow (0,\infty )$ such that $\lim _{t\rightarrow 0}th(t)=0$ and $\delta _n\lesssim \max \{h(x_n),\delta \}$ satisfies Armijo's condition for all $n$, and prove convergence under the same assumptions as in the mentioned paper. It will be shown that this growth rate of $h$ is best possible if one wants convergence of the sequence $\{x_n\}$. A specific way for choosing $\delta _n$ in a discrete way connects to Two-way Backtracking GD defined in the mentioned paper. We provide some results which either improve or are implicitly contained in those in the mentioned paper and another recent paper on avoidance of saddle points.
Scalable Gradients for Stochastic Differential Equations
Li, Xuechen, Wong, Ting-Kam Leonard, Chen, Ricky T. Q., Duvenaud, David
The adjoint sensitivity method scalably computes gradients of solutions to ordinary differential equations. We generalize this method to stochastic differential equations, allowing time-efficient and constant-memory computation of gradients with high-order adaptive solvers. Specifically, we derive a stochastic differential equation whose solution is the gradient, a memory-efficient algorithm for caching noise, and conditions under which numerical solutions converge. In addition, we combine our method with gradient-based stochastic variational inference for latent stochastic differential equations. We use our method to fit stochastic dynamics defined by neural networks, achieving competitive performance on a 50-dimensional motion capture dataset.
Addressing Value Estimation Errors in Reinforcement Learning with a State-Action Return Distribution Function
Duan, Jingliang, Guan, Yang, Ren, Yangang, Li, Shengbo Eben, Cheng, Bo
In current reinforcement learning (RL) methods, function approximation errors are known to lead to the overestimated or underestimated state-action values Q, which further lead to suboptimal policies. We show that the learning of a state-action return distribution function can be used to improve the estimation accuracy of the Q-value. We combine the distributional return function within the maximum entropy RL framework in order to develop what we call the Distributional Soft Actor-Critic algorithm, DSAC, which is an off-policy method for continuous control setting. Unlike traditional distributional Q algorithms which typically only learn a discrete return distribution, DSAC can directly learn a continuous return distribution by truncating the difference between the target and current return distribution to prevent gradient explosion. Additionally, we propose a new Parallel Asynchronous Buffer-Actor-Learner architecture (PABAL) to improve the learning efficiency. We evaluate our method on the suite of MuJoCo continuous control tasks, achieving the state of the art performance.
On Interpretability of Artificial Neural Networks
Fan, Fenglei, Xiong, Jinjun, Wang, Ge
Deep learning has achieved great successes in many important areas to dealing with text, images, video, graphs, and so on. However, the black-box nature of deep artificial neural networks has become the primary obstacle to their public acceptance and wide popularity in critical applications such as diagnosis and therapy. Due to the huge potential of deep learning, interpreting neural networks has become one of the most critical research directions. In this paper, we systematically review recent studies in understanding the mechanism of neural networks and shed light on some future directions of interpretability research (This work is still in progress).
Questioning the AI: Informing Design Practices for Explainable AI User Experiences
Liao, Q. Vera, Gruen, Daniel, Miller, Sarah
A surge of interest in explainable AI (XAI) has led to a vast collection of algorithmic work on the topic. While many recognize the necessity to incorporate explainability features in AI systems, how to address real-world user needs for understanding AI remains an open question. By interviewing 20 UX and design practitioners working on various AI products, we seek to identify gaps between the current XAI algorithmic work and practices to create explainable AI products. To do so, we develop an algorithm-informed XAI question bank in which user needs for explainability are represented as prototypical questions users might ask about the AI, and use it as a study probe. Our work contributes insights into the design space of XAI, informs efforts to support design practices in this space, and identifies opportunities for future XAI work. We also provide an extended XAI question bank and discuss how it can be used for creating user-centered XAI.
From Natural Language Instructions to Complex Processes: Issues in Chaining Trigger Action Rules
Ito, Nobuhiro, Suzuki, Yuya, Aizawa, Akiko
Automation services for complex business processes usually require a high level of information technology literacy. There is a strong demand for a smartly assisted process automation (IPA: intelligent process automation) service that enables even general users to easily use advanced automation. A natural language interface for such automation is expected as an elemental technology for the IPA realization. The workflow targeted by IPA is generally composed of a combination of multiple tasks. However, semantic parsing, one of the natural language processing methods, for such complex workflows has not yet been fully studied. The reasons are that (1) the formal expression and grammar of the workflow required for semantic analysis have not been sufficiently examined and (2) the dataset of the workflow formal expression with its corresponding natural language description required for learning workflow semantics did not exist. This paper defines a new grammar for complex workflows with chaining machine-executable meaning representations for semantic parsing. The representations are at a high abstraction level. Additionally, an approach to creating datasets is proposed based on this grammar.