由于交通的固有复杂性和不确定性,自主驾驶决策是一项具有挑战性的任务。例如,相邻的车辆可能随时改变其车道或超越,以通过慢速车辆或帮助交通流量。预期周围车辆的意图,估算其未来状态并将其整合到自动化车辆的决策过程中,可以提高复杂驾驶场景中自动驾驶的可靠性。本文提出了一种基于预测的深入强化学习(PDRL)决策模型,该模型在公路驾驶决策过程中考虑了周围车辆的操纵意图。该模型是使用真实流量数据训练的,并通过模拟平台在各种交通条件下进行了测试。结果表明,与深入的增强学习(DRL)模型相比,提出的PDRL模型通过减少碰撞数量来改善决策绩效,从而导致更安全的驾驶。
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我们考虑一个平台从隐私敏感用户收集数据的问题,以估计潜在的感兴趣的参数。我们将这个问题作为贝叶斯的最佳机制设计问题,其中个人可以共享她的(可验证的)数据以换取货币奖励或服务,但同时有一个(私人)的异构隐私成本,我们量化使用差异隐私。我们考虑两个流行的差异隐私设置,为用户提供隐私保障:中央和本地。在两个设置中,我们为估计错误建立Minimax下限,并导出(接近)用户的异构隐私损失水平的最佳估计器。在这个特征上构建,我们将机制设计问题构成为最佳选择,以估计和支付将引起用户隐私敏感性的真实报告。在隐私敏感性分布的规律性条件下,我们开发有效的算法机制来解决两个隐私设置中的这个问题。我们在中央设置中的机制可以在时间$ \ mathcal {o}(n \ log n)$,其中$ n $是当地设置中的用户数以及我们的机制承认多项式时间近似方案(PTA)。
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在本文中,我们研究了模型 - 不可知的元学习(MAML)算法的泛化特性,用于监督学习问题。我们专注于我们培训MAML模型超过$ M $任务的设置,每个都有$ n $数据点,并从两个视角表征其泛化错误:首先,我们假设测试时间的新任务是其中之一培训任务,我们表明,对于强烈凸的客观函数,预期的多余人口损失是由$ {\ mathcal {o}}(1 / mn)$的界限。其次,我们考虑MAML算法的概念任务的泛化,并表明产生的泛化误差取决于新任务的底层分布与培训过程中观察到的任务之间的总变化距离。我们的校对技术依赖于算法稳定性与算法的泛化界之间的连接。特别是,我们为元学习算法提出了一种新的稳定性定义,这使我们能够捕获每项任务的任务数量的任务数量的角色$ N $对MAML的泛化误差。
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我们考虑用于加强学习(RL)问题的模型 - 不可知的元学习(MAML)方法,其中目标是找到使用来自Markov决策过程(MDP)表示的多个任务的策略,该方法可以由随机的一步更新实现MDP的政策梯度。特别地,在MAML更新步骤中使用随机梯度对于RL问题至关重要,因为精确梯度的计算需要访问大量可能的轨迹。对于这种制剂,我们提出了一种名为随机梯度元增强学习(SG-MRL)的MAML方法的变型,并研究其收敛性。我们派生了SG-MRL的迭代和样本复杂性,以查找$ \ epsilon $ - 据我们所知,这为模型不可知的元增强学习算法提供了第一个收敛保证。我们进一步展示了我们的结果延伸到在测试时间使用多于一个随机政策梯度方法的情况的情况。最后,我们在几个深入的RL环境中凭证比较SG-MRL和MAML。
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The main objective of Prognostics and Health Management is to estimate the Remaining Useful Lifetime (RUL), namely, the time that a system or a piece of equipment is still in working order before starting to function incorrectly. In recent years, numerous machine learning algorithms have been proposed for RUL estimation, mainly focusing on providing more accurate RUL predictions. However, there are many sources of uncertainty in the problem, such as inherent randomness of systems failure, lack of knowledge regarding their future states, and inaccuracy of the underlying predictive models, making it infeasible to predict the RULs precisely. Hence, it is of utmost importance to quantify the uncertainty alongside the RUL predictions. In this work, we investigate the conformal prediction (CP) framework that represents uncertainty by predicting sets of possible values for the target variable (intervals in the case of RUL) instead of making point predictions. Under very mild technical assumptions, CP formally guarantees that the actual value (true RUL) is covered by the predicted set with a degree of certainty that can be prespecified. We study three CP algorithms to conformalize any single-point RUL predictor and turn it into a valid interval predictor. Finally, we conformalize two single-point RUL predictors, deep convolutional neural networks and gradient boosting, and illustrate their performance on the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) data sets.
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Vehicle-to-Everything (V2X) communication has been proposed as a potential solution to improve the robustness and safety of autonomous vehicles by improving coordination and removing the barrier of non-line-of-sight sensing. Cooperative Vehicle Safety (CVS) applications are tightly dependent on the reliability of the underneath data system, which can suffer from loss of information due to the inherent issues of their different components, such as sensors failures or the poor performance of V2X technologies under dense communication channel load. Particularly, information loss affects the target classification module and, subsequently, the safety application performance. To enable reliable and robust CVS systems that mitigate the effect of information loss, we proposed a Context-Aware Target Classification (CA-TC) module coupled with a hybrid learning-based predictive modeling technique for CVS systems. The CA-TC consists of two modules: A Context-Aware Map (CAM), and a Hybrid Gaussian Process (HGP) prediction system. Consequently, the vehicle safety applications use the information from the CA-TC, making them more robust and reliable. The CAM leverages vehicles path history, road geometry, tracking, and prediction; and the HGP is utilized to provide accurate vehicles' trajectory predictions to compensate for data loss (due to communication congestion) or sensor measurements' inaccuracies. Based on offline real-world data, we learn a finite bank of driver models that represent the joint dynamics of the vehicle and the drivers' behavior. We combine offline training and online model updates with on-the-fly forecasting to account for new possible driver behaviors. Finally, our framework is validated using simulation and realistic driving scenarios to confirm its potential in enhancing the robustness and reliability of CVS systems.
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Fuzzy logic has been proposed in previous studies for machine diagnosis, to overcome different drawbacks of the traditional diagnostic approaches used. Among these approaches Failure Mode and Effect Critical Analysis method(FMECA) attempts to identify potential modes and treat failures before they occur based on subjective expert judgments. Although several versions of fuzzy logic are used to improve FMECA or to replace it, since it is an extremely cost-intensive approach in terms of failure modes because it evaluates each one of them separately, these propositions have not explicitly focused on the combinatorial complexity nor justified the choice of membership functions in Fuzzy logic modeling. Within this context, we develop an optimization-based approach referred to Integrated Truth Table and Fuzzy Logic Model (ITTFLM) that smartly generates fuzzy logic rules using Truth Tables. The ITTFLM was tested on fan data collected in real-time from a plant machine. In the experiment, three types of membership functions (Triangular, Trapezoidal, and Gaussian) were used. The ITTFLM can generate outputs in 5ms, the results demonstrate that this model based on the Trapezoidal membership functions identifies the failure states with high accuracy, and its capability of dealing with large numbers of rules and thus meets the real-time constraints that usually impact user experience.
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With the advent of deep learning application on edge devices, researchers actively try to optimize their deployments on low-power and restricted memory devices. There are established compression method such as quantization, pruning, and architecture search that leverage commodity hardware. Apart from conventional compression algorithms, one may redesign the operations of deep learning models that lead to more efficient implementation. To this end, we propose EuclidNet, a compression method, designed to be implemented on hardware which replaces multiplication, $xw$, with Euclidean distance $(x-w)^2$. We show that EuclidNet is aligned with matrix multiplication and it can be used as a measure of similarity in case of convolutional layers. Furthermore, we show that under various transformations and noise scenarios, EuclidNet exhibits the same performance compared to the deep learning models designed with multiplication operations.
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Performance metrics-driven context caching has a profound impact on throughput and response time in distributed context management systems for real-time context queries. This paper proposes a reinforcement learning based approach to adaptively cache context with the objective of minimizing the cost incurred by context management systems in responding to context queries. Our novel algorithms enable context queries and sub-queries to reuse and repurpose cached context in an efficient manner. This approach is distinctive to traditional data caching approaches by three main features. First, we make selective context cache admissions using no prior knowledge of the context, or the context query load. Secondly, we develop and incorporate innovative heuristic models to calculate expected performance of caching an item when making the decisions. Thirdly, our strategy defines a time-aware continuous cache action space. We present two reinforcement learning agents, a value function estimating actor-critic agent and a policy search agent using deep deterministic policy gradient method. The paper also proposes adaptive policies such as eviction and cache memory scaling to complement our objective. Our method is evaluated using a synthetically generated load of context sub-queries and a synthetic data set inspired from real world data and query samples. We further investigate optimal adaptive caching configurations under different settings. This paper presents, compares, and discusses our findings that the proposed selective caching methods reach short- and long-term cost- and performance-efficiency. The paper demonstrates that the proposed methods outperform other modes of context management such as redirector mode, and database mode, and cache all policy by up to 60% in cost efficiency.
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We propose a framework in which multiple entities collaborate to build a machine learning model while preserving privacy of their data. The approach utilizes feature embeddings from shared/per-entity feature extractors transforming data into a feature space for cooperation between entities. We propose two specific methods and compare them with a baseline method. In Shared Feature Extractor (SFE) Learning, the entities use a shared feature extractor to compute feature embeddings of samples. In Locally Trained Feature Extractor (LTFE) Learning, each entity uses a separate feature extractor and models are trained using concatenated features from all entities. As a baseline, in Cooperatively Trained Feature Extractor (CTFE) Learning, the entities train models by sharing raw data. Secure multi-party algorithms are utilized to train models without revealing data or features in plain text. We investigate the trade-offs among SFE, LTFE, and CTFE in regard to performance, privacy leakage (using an off-the-shelf membership inference attack), and computational cost. LTFE provides the most privacy, followed by SFE, and then CTFE. Computational cost is lowest for SFE and the relative speed of CTFE and LTFE depends on network architecture. CTFE and LTFE provide the best accuracy. We use MNIST, a synthetic dataset, and a credit card fraud detection dataset for evaluations.
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