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A Global Transport Capacity Risk Prediction Method for Rail Transit Based on Gaussian Bayesian Network

arXiv.org Artificial Intelligence

Rail transit plays an increasingly important role in modern Since transport capacity risks at the rail transit network level urban transportation with its advantages of large capacity, good have a large influence surface and propagation inertia, different punctuality, high safety, environmental friendliness and low cost, passenger flow conditions will also have different impacts on the and has become the backbone and important support of modern safety of the network, if effective preventive measures are not transportation. Although the safety of rail transit is higher than taken, once the risk propagation starts, it can easily lead to a that of conventional road traffic, due to the large scale of rail rapid decline in the safety of the whole network and eventually transit network, heavy transportation tasks and close coupling lead to safety accidents. Therefore, the prediction of transport between lines, once a failure or safety accident occurs, it will capacity risk on the basis of transport capacity risk assessment have a great impact on urban transportation. For example, on has important practical significance for the safe operation of rail December 22, 2009, around 7:00 a.m., a collision occurred on transit network.


Causal Discovery from Temporal Data: An Overview and New Perspectives

arXiv.org Artificial Intelligence

Temporal data, representing chronological observations of complex systems, has always been a typical data structure that can be widely generated by many domains, such as industry, medicine and finance. Analyzing this type of data is extremely valuable for various applications. Thus, different temporal data analysis tasks, eg, classification, clustering and prediction, have been proposed in the past decades. Among them, causal discovery, learning the causal relations from temporal data, is considered an interesting yet critical task and has attracted much research attention. Existing causal discovery works can be divided into two highly correlated categories according to whether the temporal data is calibrated, ie, multivariate time series causal discovery, and event sequence causal discovery. However, most previous surveys are only focused on the time series causal discovery and ignore the second category. In this paper, we specify the correlation between the two categories and provide a systematical overview of existing solutions. Furthermore, we provide public datasets, evaluation metrics and new perspectives for temporal data causal discovery.


Learning from Data Streams: An Overview and Update

arXiv.org Artificial Intelligence

The literature on machine learning in the context of data streams is vast and growing. However, many of the defining assumptions regarding data-stream learning tasks are too strong to hold in practice, or are even contradictory such that they cannot be met in the contexts of supervised learning. Algorithms are chosen and designed based on criteria which are often not clearly stated, for problem settings not clearly defined, tested in unrealistic settings, and/or in isolation from related approaches in the wider literature. This puts into question the potential for real-world impact of many approaches conceived in such contexts, and risks propagating a misguided research focus. We propose to tackle these issues by reformulating the fundamental definitions and settings of supervised data-stream learning with regard to contemporary considerations of concept drift and temporal dependence; and we take a fresh look at what constitutes a supervised data-stream learning task, and a reconsideration of algorithms that may be applied to tackle such tasks. Through and in reflection of this formulation and overview, helped by an informal survey of industrial players dealing with real-world data streams, we provide recommendations. Our main emphasis is that learning from data streams does not impose a single-pass or online-learning approach, or any particular learning regime; and any constraints on memory and time are not specific to streaming. Meanwhile, there exist established techniques for dealing with temporal dependence and concept drift, in other areas of the literature. For the data streams community, we thus encourage a shift in research focus, from dealing with often-artificial constraints and assumptions on the learning mode, to issues such as robustness, privacy, and interpretability which are increasingly relevant to learning in data streams in academic and industrial settings.


Confident Neural Network Regression with Bootstrapped Deep Ensembles

arXiv.org Artificial Intelligence

With the rise of the popularity and usage of neural networks, trustworthy uncertainty estimation is becoming increasingly essential. One of the most prominent uncertainty estimation methods is Deep Ensembles (Lakshminarayanan et al., 2017) . A classical parametric model has uncertainty in the parameters due to the fact that the data on which the model is build is a random sample. A modern neural network has an additional uncertainty component since the optimization of the network is random. Lakshminarayanan et al. (2017) noted that Deep Ensembles do not incorporate the classical uncertainty induced by the effect of finite data. In this paper, we present a computationally cheap extension of Deep Ensembles for the regression setting, called Bootstrapped Deep Ensembles, that explicitly takes this classical effect of finite data into account using a modified version of the parametric bootstrap. We demonstrate through an experimental study that our method significantly improves upon standard Deep Ensembles


A Probabilistic Approach to Self-Supervised Learning using Cyclical Stochastic Gradient MCMC

arXiv.org Artificial Intelligence

In this paper we present a practical Bayesian self-supervised learning method with Cyclical Stochastic Gradient Hamiltonian Monte Carlo (cSGHMC). Within this framework, we place a prior over the parameters of a self-supervised learning model and use cSGHMC to approximate the high dimensional and multimodal posterior distribution over the embeddings. By exploring an expressive posterior over the embeddings, Bayesian self-supervised learning produces interpretable and diverse representations. Marginalizing over these representations yields a significant gain in performance, calibration and out-of-distribution detection on a variety of downstream classification tasks. We provide experimental results on multiple classification tasks on four challenging datasets. Moreover, we demonstrate the effectiveness of the proposed method in out-of-distribution detection using the SVHN and CIFAR-10 datasets.


Machine Learning Small Molecule Properties in Drug Discovery

arXiv.org Artificial Intelligence

Machine learning (ML) is a promising approach for predicting small molecule properties in drug discovery. Here, we provide a comprehensive overview of various ML methods introduced for this purpose in recent years. We review a wide range of properties, including binding affinities, solubility, and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity). We discuss existing popular datasets and molecular descriptors and embeddings, such as chemical fingerprints and graph-based neural networks. We highlight also challenges of predicting and optimizing multiple properties during hit-to-lead and lead optimization stages of drug discovery and explore briefly possible multi-objective optimization techniques that can be used to balance diverse properties while optimizing lead candidates. Finally, techniques to provide an understanding of model predictions, especially for critical decision-making in drug discovery are assessed. Overall, this review provides insights into the landscape of ML models for small molecule property predictions in drug discovery. So far, there are multiple diverse approaches, but their performances are often comparable. Neural networks, while more flexible, do not always outperform simpler models. This shows that the availability of high-quality training data remains crucial for training accurate models and there is a need for standardized benchmarks, additional performance metrics, and best practices to enable richer comparisons between the different techniques and models that can shed a better light on the differences between the many techniques.


An enhanced motion planning approach by integrating driving heterogeneity and long-term trajectory prediction for automated driving systems

arXiv.org Artificial Intelligence

The benefits of ADSs can be guaranteed by making the driving experience in complex driving environments more comfortable and safer (Sarker et al., 2019). New perception technologies enable ADSs to detect the surrounding traffic. When surrounding traffic, such as other vehicles, pedestrians, and cyclists, is detected, a motion-planning algorithm can generate a safe path for the ADS (Frazzoli, 2000; Shiller and Gwo, 1991). The generated path is continuously updated using decision and control technologies based on the surrounding environment. One of the greatest challenges for ADSs is the uncertainty of the surrounding dynamic environment (González et al., 2016). An ADS must adapt to these changing conditions and make decisions that prioritize safety and efficiency.


Empirical Translation Process Research: Past and Possible Future Perspectives

arXiv.org Artificial Intelligence

By the mid-1980s a branch in of this field now often referred to as Cognitive Translation Studies (CTS, or more recently CTIS, Cognitive Translation and Interpretation Studies) started to investigate and model how the translators' minds work -how translators create meaning, how they arrive at strategies and translation choices, how translation competence develops, how cultural and linguistic factors impact translated text, etc. (see, e.g., Risku 2012). Studies in this line of research "refer to and expand" (Risku 2012, 675) models of the mind as developed in Cognitive Science, to explain translators' behavior and translation processes. While the first attempts to study translation as a cognitive activity date back to the 1960s and 1970s (e.g., Albir 2015, Muñoz 2017), Translation Process Research (TPR) is often said to To be published in Translation, Cognition and Behavior: "Translation and cognition in the 21st century: Goals met, goals ahead" begin in the 1980s with the analysis of thinking aloud protocols (TAP) and to investigate "What happens in the minds of translators" (Krings 1986; 2001; see also Königs 1987) and to assess "by what observable and presumed mental processes do translators arrive at their translations?"


Reward Shaping for Building Trustworthy Robots in Sequential Human-Robot Interaction

arXiv.org Artificial Intelligence

Trust-aware human-robot interaction (HRI) has received increasing research attention, as trust has been shown to be a crucial factor for effective HRI. Research in trust-aware HRI discovered a dilemma -- maximizing task rewards often leads to decreased human trust, while maximizing human trust would compromise task performance. In this work, we address this dilemma by formulating the HRI process as a two-player Markov game and utilizing the reward-shaping technique to improve human trust while limiting performance loss. Specifically, we show that when the shaping reward is potential-based, the performance loss can be bounded by the potential functions evaluated at the final states of the Markov game. We apply the proposed framework to the experience-based trust model, resulting in a linear program that can be efficiently solved and deployed in real-world applications. We evaluate the proposed framework in a simulation scenario where a human-robot team performs a search-and-rescue mission. The results demonstrate that the proposed framework successfully modifies the robot's optimal policy, enabling it to increase human trust at a minimal task performance cost.


An Auction-based Coordination Strategy for Task-Constrained Multi-Agent Stochastic Planning with Submodular Rewards

arXiv.org Artificial Intelligence

Abstract--In many domains such as transportation and logistics, search and rescue, or cooperative surveillance, tasks are pending to be allocated with the consideration of possible execution uncertainties. Existing task coordination algorithms either ignore the stochastic process or suffer from the computational intensity. Taking advantage of the'weakly coupled' feature of the problem and the opportunity for coordination in advance, we propose a decentralized auction-based coordination strategy using a newly formulated score function which is generated by forming the problem into task-constrained Markov decision processes (MDPs). The proposed method guarantees convergence and at least 50% optimality in the premise of a submodular reward function. Furthermore, for the implementation on large-scale applications, an approximate variant of the proposed method, namely Deep Auction, is also suggested with the use of neural networks, which is evasive of the troublesome for constructing MDPs. Inspired by the well-known actor-critic architecture, two Transformers are used to map observations to action probabilities and cumulative rewards respectively. Finally, we demonstrate the performance of the two proposed approaches in the context of drone deliveries, where the stochastic planning for the drone league is cast into a stochastic price-collecting Vehicle Routing Problem (VRP) with time windows. Simulation results are compared with state-of-the-art methods in terms of solution quality, planning efficiency and scalability. Cooperative systems of multiple agents, which features a flexible structure, parallel-processing ability, and scalability, are of great interest, especially for those operating on the unmanned aerial platform [1], such as cooperative surveillance, search and rescue [2][3], border patrolling, etc. Among its various instantiations, there is a specific but widespread category of assigning tasks among team members with a global goal, followed by an independent and possibly stochastic task execution. For example, in deliveries of parcels [4], tasks are allocated to individual vehicles, and the vehicles deliver their allocated items in sequence, without interference from other executors. However, the delivery may subject to stochastic travel delays between destinations. Also, in multi-target tracking [5], agents decide the tracking targets and the best action to track based on the estimation of targe manoeuvring.