由于道路上越来越多的车辆,城市的交通管理已成为一个主要问题。智能交通系统(其)可以帮助城市交通管理者通过提供准确的流量预测来解决问题。为此,它需要一种可靠的业务预测算法,其可以基于过去和当前的业务数据在多个时间步骤中提供准确的流量预测。近年来,已经提出了许多不同的交通预测方法,这些方法已经证明了它们在准确性方面的有效性。然而,这些方法中的大多数都认为仅包括空间信息或时间信息并忽略了其他的效果。在本文中,为了解决上述问题,使用空间和时间依赖性开发了基于深度学习的方法。要考虑时空依赖项,基于交通相似度和距离等属性选择特定即时的附近的道路传感器。使用潜在空间映射的概念交叉连接两个预训练的深度自动编码器,并且使用从所选附近传感器的流量数据培训所得模型作为输入。使用从洛杉矶和湾区的不同高速公路上安装的Loop Detector传感器收集的现实世界交通数据培训了所提出的深度学习方法。来自加利福尼亚州运输绩效测量系统(PEMS)的网络门户网站自由提供交通数据。通过将其与许多机/深度学习方法进行比较来验证所提出的方法的有效性。已经发现,所提出的方法即使对于比其他技术最小的误差,即使超过60分钟的前方预测也提供了准确的流量预测结果。
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Spatiotemporal forecasting has various applications in neuroscience, climate and transportation domain. Traffic forecasting is one canonical example of such learning task. The task is challenging due to (1) complex spatial dependency on road networks, (2) non-linear temporal dynamics with changing road conditions and (3) inherent difficulty of long-term forecasting. To address these challenges, we propose to model the traffic flow as a diffusion process on a directed graph and introduce Diffusion Convolutional Recurrent Neural Network (DCRNN), a deep learning framework for traffic forecasting that incorporates both spatial and temporal dependency in the traffic flow. Specifically, DCRNN captures the spatial dependency using bidirectional random walks on the graph, and the temporal dependency using the encoder-decoder architecture with scheduled sampling. We evaluate the framework on two real-world large scale road network traffic datasets and observe consistent improvement of 12% -15% over state-of-the-art baselines.
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As ride-hailing services become increasingly popular, being able to accurately predict demand for such services can help operators efficiently allocate drivers to customers, and reduce idle time, improve congestion, and enhance the passenger experience. This paper proposes UberNet, a deep learning Convolutional Neural Network for short-term prediction of demand for ride-hailing services. UberNet empploys a multivariate framework that utilises a number of temporal and spatial features that have been found in the literature to explain demand for ride-hailing services. The proposed model includes two sub-networks that aim to encode the source series of various features and decode the predicting series, respectively. To assess the performance and effectiveness of UberNet, we use 9 months of Uber pickup data in 2014 and 28 spatial and temporal features from New York City. By comparing the performance of UberNet with several other approaches, we show that the prediction quality of the model is highly competitive. Further, Ubernet's prediction performance is better when using economic, social and built environment features. This suggests that Ubernet is more naturally suited to including complex motivators in making real-time passenger demand predictions for ride-hailing services.
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Traffic state prediction in a transportation network is paramount for effective traffic operations and management, as well as informed user and system-level decision-making. However, long-term traffic prediction (beyond 30 minutes into the future) remains challenging in current research. In this work, we integrate the spatio-temporal dependencies in the transportation network from network modeling, together with the graph convolutional network (GCN) and graph attention network (GAT). To further tackle the dramatic computation and memory cost caused by the giant model size (i.e., number of weights) caused by multiple cascaded layers, we propose sparse training to mitigate the training cost, while preserving the prediction accuracy. It is a process of training using a fixed number of nonzero weights in each layer in each iteration. We consider the problem of long-term traffic speed forecasting for a real large-scale transportation network data from the California Department of Transportation (Caltrans) Performance Measurement System (PeMS). Experimental results show that the proposed GCN-STGT and GAT-STGT models achieve low prediction errors on short-, mid- and long-term prediction horizons, of 15, 30 and 45 minutes in duration, respectively. Using our sparse training, we could train from scratch with high sparsity (e.g., up to 90%), equivalent to 10 times floating point operations per second (FLOPs) reduction on computational cost using the same epochs as dense training, and arrive at a model with very small accuracy loss compared with the original dense training
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Long-term traffic prediction is highly challenging due to the complexity of traffic systems and the constantly changing nature of many impacting factors. In this paper, we focus on the spatio-temporal factors, and propose a graph multi-attention network (GMAN) to predict traffic conditions for time steps ahead at different locations on a road network graph. GMAN adapts an encoder-decoder architecture, where both the encoder and the decoder consist of multiple spatio-temporal attention blocks to model the impact of the spatio-temporal factors on traffic conditions. The encoder encodes the input traffic features and the decoder predicts the output sequence. Between the encoder and the decoder, a transform attention layer is applied to convert the encoded traffic features to generate the sequence representations of future time steps as the input of the decoder. The transform attention mechanism models the direct relationships between historical and future time steps that helps to alleviate the error propagation problem among prediction time steps. Experimental results on two real-world traffic prediction tasks (i.e., traffic volume prediction and traffic speed prediction) demonstrate the superiority of GMAN. In particular, in the 1 hour ahead prediction, GMAN outperforms state-of-the-art methods by up to 4% improvement in MAE measure. The source code is available at https://github.com/zhengchuanpan/GMAN.
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近年来,图形神经网络(GNN)与复发性神经网络(RNN)的变体相结合,在时空预测任务中达到了最先进的性能。对于流量预测,GNN模型使用道路网络的图形结构来解释链接和节点之间的空间相关性。最近的解决方案要么基于复杂的图形操作或避免预定义的图。本文提出了一种新的序列结构,以使用具有稀疏体系结构的GNN-RNN细胞在多个抽象的抽象上提取时空相关性,以减少训练时间与更复杂的设计相比。通过多个编码器编码相同的输入序列,并随着编码层的增量增加,使网络能够通过多级抽象来学习一般和详细的信息。我们进一步介绍了来自加拿大蒙特利尔的街道细分市场流量数据的新基准数据集。与高速公路不同,城市路段是循环的,其特征是复杂的空间依赖性。与基线方法相比,一小时预测的实验结果和我们的MSLTD街道级段数据集对我们的模型提高了7%以上,同时将计算资源要求提高了一半以上竞争方法。
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流量预测在智能运输系统中交通控制和调度任务的实现中起着重要作用。随着数据源的多元化,合理地使用丰富的流量数据来对流量流中复杂的时空依赖性和非线性特征进行建模是智能运输系统的关键挑战。此外,清楚地评估从不同数据中提取的时空特征的重要性成为一个挑战。提出了双层 - 空间时间特征提取和评估(DL -STFEE)模型。 DL-STFEE的下层是时空特征提取层。流量数据中的空间和时间特征是通过多画图卷积和注意机制提取的,并生成了空间和时间特征的不同组合。 DL-STFEE的上层是时空特征评估层。通过高维自我注意力发项机制产生的注意力评分矩阵,空间特征组合被融合和评估,以便获得不同组合对预测效应的影响。在实际的流量数据集上进行了三组实验,以表明DL-STFEE可以有效地捕获时空特征并评估不同时空特征组合的重要性。
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Accurate short-term traffic prediction plays a pivotal role in various smart mobility operation and management systems. Currently, most of the state-of-the-art prediction models are based on graph neural networks (GNNs), and the required training samples are proportional to the size of the traffic network. In many cities, the available amount of traffic data is substantially below the minimum requirement due to the data collection expense. It is still an open question to develop traffic prediction models with a small size of training data on large-scale networks. We notice that the traffic states of a node for the near future only depend on the traffic states of its localized neighborhoods, which can be represented using the graph relational inductive biases. In view of this, this paper develops a graph network (GN)-based deep learning model LocaleGN that depicts the traffic dynamics using localized data aggregating and updating functions, as well as the node-wise recurrent neural networks. LocaleGN is a light-weighted model designed for training on few samples without over-fitting, and hence it can solve the problem of few-sample traffic prediction. The proposed model is examined on predicting both traffic speed and flow with six datasets, and the experimental results demonstrate that LocaleGN outperforms existing state-of-the-art baseline models. It is also demonstrated that the learned knowledge from LocaleGN can be transferred across cities. The research outcomes can help to develop light-weighted traffic prediction systems, especially for cities lacking historically archived traffic data.
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检测,预测和减轻交通拥堵是针对改善运输网络的服务水平的目标。随着对更高分辨率的更大数据集的访问,深度学习对这种任务的相关性正在增加。近年来几篇综合调查论文总结了运输领域的深度学习应用。然而,运输网络的系统动态在非拥挤状态和拥塞状态之间变化大大变化 - 从而需要清楚地了解对拥堵预测特异性特异性的挑战。在这项调查中,我们在与检测,预测和缓解拥堵相关的任务中,介绍了深度学习应用的当前状态。重复和非经常性充血是单独讨论的。我们的调查导致我们揭示了当前研究状态的固有挑战和差距。最后,我们向未来的研究方向提出了一些建议,因为所确定的挑战的答案。
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作为自然现象的地震,历史上不断造成伤害和人类生活的损失。地震预测是任何社会计划的重要方面,可以增加公共准备,并在很大程度上减少损坏。然而,由于地震的随机特征以及实现了地震预测的有效和可靠模型的挑战,迄今为止努力一直不足,需要新的方法来解决这个问题。本文意识到​​这些问题,提出了一种基于注意机制(AM),卷积神经网络(CNN)和双向长短期存储器(BILSTM)模型的新型预测方法,其可以预测数量和最大幅度中国大陆各地区的地震为基于该地区的地震目录。该模型利用LSTM和CNN具有注意机制,以更好地关注有效的地震特性并产生更准确的预测。首先,将零阶保持技术应用于地震数据上的预处理,使得模型的输入数据更适当。其次,为了有效地使用空间信息并减少输入数据的维度,CNN用于捕获地震数据之间的空间依赖性。第三,使用Bi-LSTM层来捕获时间依赖性。第四,引入了AM层以突出其重要的特征来实现更好的预测性能。结果表明,该方法具有比其他预测方法更好的性能和概括能力。
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最近,深度学习方法在交通预测方面取得了长足的进步,但它们的性能取决于大量的历史数据。实际上,我们可能会面临数据稀缺问题。在这种情况下,深度学习模型无法获得令人满意的性能。转移学习是解决数据稀缺问题的一种有前途的方法。但是,流量预测中现有的转移学习方法主要基于常规网格数据,这不适用于流量网络中固有的图形数据。此外,现有的基于图的模型只能在道路网络中捕获共享的流量模式,以及如何学习节点特定模式也是一个挑战。在本文中,我们提出了一种新颖的传输学习方法来解决流量预测,几乎可以将知识从数据富的源域转移到数据范围的目标域。首先,提出了一个空间图形神经网络,该网络可以捕获不同道路网络的节点特异性时空交通模式。然后,为了提高转移的鲁棒性,我们设计了一种基于模式的转移策略,我们利用基于聚类的机制来提炼源域中的常见时空模式,并使用这些知识进一步提高了预测性能目标域。现实世界数据集的实验验证了我们方法的有效性。
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Traffic forecasting has attracted widespread attention recently. In reality, traffic data usually contains missing values due to sensor or communication errors. The Spatio-temporal feature in traffic data brings more challenges for processing such missing values, for which the classic techniques (e.g., data imputations) are limited: 1) in temporal axis, the values can be randomly or consecutively missing; 2) in spatial axis, the missing values can happen on one single sensor or on multiple sensors simultaneously. Recent models powered by Graph Neural Networks achieved satisfying performance on traffic forecasting tasks. However, few of them are applicable to such a complex missing-value context. To this end, we propose GCN-M, a Graph Convolutional Network model with the ability to handle the complex missing values in the Spatio-temporal context. Particularly, we jointly model the missing value processing and traffic forecasting tasks, considering both local Spatio-temporal features and global historical patterns in an attention-based memory network. We propose as well a dynamic graph learning module based on the learned local-global features. The experimental results on real-life datasets show the reliability of our proposed method.
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Wind power forecasting helps with the planning for the power systems by contributing to having a higher level of certainty in decision-making. Due to the randomness inherent to meteorological events (e.g., wind speeds), making highly accurate long-term predictions for wind power can be extremely difficult. One approach to remedy this challenge is to utilize weather information from multiple points across a geographical grid to obtain a holistic view of the wind patterns, along with temporal information from the previous power outputs of the wind farms. Our proposed CNN-RNN architecture combines convolutional neural networks (CNNs) and recurrent neural networks (RNNs) to extract spatial and temporal information from multi-dimensional input data to make day-ahead predictions. In this regard, our method incorporates an ultra-wide learning view, combining data from multiple numerical weather prediction models, wind farms, and geographical locations. Additionally, we experiment with global forecasting approaches to understand the impact of training the same model over the datasets obtained from multiple different wind farms, and we employ a method where spatial information extracted from convolutional layers is passed to a tree ensemble (e.g., Light Gradient Boosting Machine (LGBM)) instead of fully connected layers. The results show that our proposed CNN-RNN architecture outperforms other models such as LGBM, Extra Tree regressor and linear regression when trained globally, but fails to replicate such performance when trained individually on each farm. We also observe that passing the spatial information from CNN to LGBM improves its performance, providing further evidence of CNN's spatial feature extraction capabilities.
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交通流量预测是智能运输系统的重要组成部分,从而受到了研究人员的关注。但是,交通道路之间的复杂空间和时间依赖性使交通流量的预测具有挑战性。现有方法通常是基于图形神经网络,使用交通网络的预定义空间邻接图来建模空间依赖性,而忽略了道路节点之间关系的动态相关性。此外,他们通常使用独立的时空组件来捕获时空依赖性,并且不会有效地对全局时空依赖性进行建模。本文提出了一个新的时空因果图形注意网络(STCGAT),以解决上述挑战。在STCGAT中,我们使用一种节点嵌入方法,可以在每个时间步骤中自适应生成空间邻接子图,而无需先验地理知识和对不同时间步骤动态生成图的拓扑的精细颗粒建模。同时,我们提出了一个有效的因果时间相关成分,其中包含节点自适应学习,图形卷积以及局部和全局因果关系卷积模块,以共同学习局部和全局时空依赖性。在四个真正的大型流量数据集上进行的广泛实验表明,我们的模型始终优于所有基线模型。
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交通速度预测是许多有价值应用程序的关键,由于其各种影响因素,它也是一项具有挑战性的任务。最近的工作试图通过各种混合模型获得更多信息,从而提高了预测准确性。但是,这些方法的空间信息采集方案存在两级分化问题。建模很简单,但包含很少的空间信息,或者建模是完整的,但缺乏灵活性。为了基于确保灵活性引入更多空间信息,本文提出了IRNET(可转让的交叉点重建网络)。首先,本文将相交重建为与相同结构的虚拟交集,从而简化了道路网络的拓扑结构。然后,将空间信息细分为交叉信息和交通流向的序列信息,并通过各种模型获得时空特征。第三,一种自我发项机制用于融合时空特征以进行预测。在与基线的比较实验中,不仅预测效应,而且转移性能具有明显的优势。
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为了减少乘客等候时间和驾驶员搜索摩擦,骑行公司需要准确地预测时空需求和供需差距。然而,由于乘坐乘车系统中的需求和供需差距有关的时空依赖性,对需求和供需差距的准确预测是一项艰巨的任务。此外,由于机密性和隐私问题,乘车通过删除区域的空间邻接信息,有时会向研究人员发布,这阻碍了时空依赖的检测。为此,本文提出了一种新颖的时空深度学习架构,用于预测具有匿名空间邻接信息的乘车 - HaIning系统中的需求和供需差距,其与时空深度学习架构集成了特征重要性层含有一维卷积神经网络(CNN)和区域分布独立的复发性神经网络(INDRNN)。开发的架构与DIDI Chuxing的真实世界数据集进行了测试,这表明我们的模型基于所提出的体系结构可以优于传统的时间序列模型(例如,Arima)和机器学习模型(例如,梯度升压机,分布式随机林,广义线性模型,人工神经网络)。另外,该特征重要层通过揭示预测中使用的输入特征的贡献提供了模型的解释。
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准确预测网络范围的交通状况对于智能运输系统至关重要。在过去十年中,机器学习技术已被广泛用于此任务,导致最先进的性能。我们提出了一种新颖的深入学习模型,图卷积出的经常性神经网络(GCGRNN),预测网络范围,多步交通量。 GCGRNN可以在历史流量数据中自动捕获交通传感器和时间依赖性之间的空间相关性。我们已经使用加利福尼亚州洛杉矶的150个传感器中提取的两个交通数据集进行了评估我们的模型,分别在一小时和15分钟的时间分辨率。结果表明,我们的模型在预测准确性方面优于其他五个基准模型。例如,与使用每小时数据集的最新的扩散卷积经常性神经网络(DCRNN)模型相比,我们的模型将MAE减少25.3%,RMSE以29.2%,并用20.2%的MAPE。我们的模型还可以比DCRNN更快的培训达52%。 GCGRNN的数据和实现可以在https://github.com/leilin-research/gcgrnn找到。
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预测交通状况非常具有挑战性,因为每条道路在空间和时间上都高度依赖。最近,为了捕获这种空间和时间依赖性,已经引入了专门设计的架构,例如图形卷积网络和时间卷积网络。尽管流量预测取得了显着进展,但我们发现基于深度学习的流量预测模型仍然在某些模式中失败,主要是在事件情况下(例如,快速速度下降)。尽管通常认为这些故障是由于不可预测的噪声造成的,但我们发现可以通过考虑以前的失败来纠正这些故障。具体而言,我们观察到这些失败中的自相关错误,这表明仍然存在一些可预测的信息。在这项研究中,为了捕获错误的相关性,我们引入了Rescal,Rescal是流量预测的剩余估计模块,作为广泛适用的附加模块,用于现有的流量预测模型。我们的恢复通过使用以前的错误和图形信号来估算未来错误,从而实时校准现有模型的预测。对METR-LA和PEMS-BAY进行的广泛实验表明,我们的恢复可以正确捕获错误的相关性,并在事件情况下纠正各种流量预测模型的故障。
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通过准确,及时的流量预测,可以预先预测受影响的交通状况,以指导机构和居民适当地应对交通模式的变化。但是,例如,关于交通预测的现有作品主要依赖于仅在1小时以下的短期预测的历史流量模式。为了更好地管理未来的道路能力并适应社会和人类的影响,提出一个灵活而全面的框架以预测公共用户和运输机构的长期交通状况至关重要。在本文中,考虑到社交媒体的功能,弥合了强大的长期交通预测的差距。首先实施了相关研究和线性回归模型,以评估两个时间序列数据,流量强度和Twitter数据强度之间的相关性的重要性。然后将两个时间序列数据提供给我们提出的社会意识框架,即交通扭转变压器,该框架将大自然语言表示形式集成到时间序列记录中以进行长期流量预测。大西雅图地区的实验结果表明,我们提出的模型在所有评估矩阵中都优于基线模型。这个由NLP加入的社会感知框架可以成为交通代理机构的网络交通预测和管理的宝贵实现。
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使用图形卷积网络(GCN)构建时空网络已成为预测交通信号的最流行方法之一。但是,当使用GCN进行交通速度预测时,常规方法通常将传感器之间的关系作为均匀图,并使用传感器累积的数据来学习邻接矩阵。但是,传感器之间的空间相关性并未指定为一个,而是从各种观点方面定义不同。为此,我们旨在研究流量信号数据中固有的异质特征,以以各种方式学习传感器之间的隐藏关系。具体而言,我们设计了一种方法来通过将传感器之间的空间关系分为静态和动态模块来构造每个模块的异质图。我们提出了一个基于网络分散注意力的基于异质性 - 感知图形卷积网络(HAGCN)方法,该方法通过在异质图中考虑每个通道的重要性来汇总相邻节点的隐藏状态。实际流量数据集的实验结果验证了所提出的方法的有效性,比现有模型取得了6.35%的改善,并实现了最先进的预测性能。
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