Transportation mode classification, the process of predicting the class labels of moving objects transportation modes, has been widely applied to a variety of real world applications, such as traffic management, urban computing, and behavior study. However, existing studies of transportation mode classification typically extract the explicit features of trajectory data but fail to capture the implicit features that affect the classification performance. In addition, most of the existing studies also prefer to apply RNN-based models to embed trajectories, which is only suitable for classifying small-scale data. To tackle the above challenges, we propose an effective and scalable framework for transportation mode classification over GPS trajectories, abbreviated Estimator. Estimator is established on a developed CNN-TCN architecture, which is capable of leveraging the spatial and temporal hidden features of trajectories to achieve high effectiveness and efficiency. Estimator partitions the entire traffic space into disjointed spatial regions according to traffic conditions, which enhances the scalability significantly and thus enables parallel transportation classification. Extensive experiments using eight public real-life datasets offer evidence that Estimator i) achieves superior model effectiveness (i.e., 99% Accuracy and 0.98 F1-score), which outperforms state-of-the-arts substantially; ii) exhibits prominent model efficiency, and obtains 7-40x speedups up over state-of-the-arts learning-based methods; and iii) shows high model scalability and robustness that enables large-scale classification analytics.
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人和车辆轨迹体现了运输基础设施的重要信息,轨迹相似性计算是许多涉及轨迹数据分析的现实世界应用中的功能。最近,基于深度学习的轨迹相似性技术使得能够提高传统相似性技术提高效率和适应性。然而,现有的轨迹相似度学习提案强调了时间相似性的空间相似性,使得它们次开用于时光分析。为此,我们提出了ST2VEC,这是一种基于轨迹表示的学习架构,其考虑了道路网络中的时空相似度学习的对轨迹对之间的细粒度的空间和时间相关性。据我们所知,这是第一个用于时空轨迹相似性分析的深学习建议。具体而言,ST2VEC包含三个阶段:(i)培训选择代表性培训样本的数据准备; (ii)设计轨迹的空间和时间建模,其中设计了通用时间建模模块(TMM)的轨迹的空间和时间特征; (iii)时空共关节融合(STCF),其中开发了统一的融合(UF)方法,以帮助产生统一的时空轨迹嵌入,以捕获轨迹之间的时空相似关系。此外,由课程概念启发,ST2VEC采用课程学习进行模型优化,以提高融合和有效性。实验研究提供了证据表明,ST2VEC显着胜过了所有最先进的竞争对手,在有效性,效率和可扩展性方面,同时显示出低参数敏感性和良好的模型稳健性。
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GPS trajectories are the essential foundations for many trajectory-based applications, such as travel time estimation, traffic prediction and trajectory similarity measurement. Most applications require a large amount of high sample rate trajectories to achieve a good performance. However, many real-life trajectories are collected with low sample rate due to energy concern or other constraints.We study the task of trajectory recovery in this paper as a means for increasing the sample rate of low sample trajectories. Currently, most existing works on trajectory recovery follow a sequence-to-sequence diagram, with an encoder to encode a trajectory and a decoder to recover real GPS points in the trajectory. However, these works ignore the topology of road network and only use grid information or raw GPS points as input. Therefore, the encoder model is not able to capture rich spatial information of the GPS points along the trajectory, making the prediction less accurate and lack spatial consistency. In this paper, we propose a road network enhanced transformer-based framework, namely RNTrajRec, for trajectory recovery. RNTrajRec first uses a graph model, namely GridGNN, to learn the embedding features of each road segment. It next develops a spatial-temporal transformer model, namely GPSFormer, to learn rich spatial and temporal features along with a Sub-Graph Generation module to capture the spatial features for each GPS point in the trajectory. It finally forwards the outputs of encoder model into a multi-task decoder model to recover the missing GPS points. Extensive experiments based on three large-scale real-life trajectory datasets confirm the effectiveness of our approach.
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“轨迹”是指由地理空间中的移动物体产生的迹线,通常由一系列按时间顺序排列的点表示,其中每个点由地理空间坐标集和时间戳组成。位置感应和无线通信技术的快速进步使我们能够收集和存储大量的轨迹数据。因此,许多研究人员使用轨迹数据来分析各种移动物体的移动性。在本文中,我们专注于“城市车辆轨迹”,这是指城市交通网络中车辆的轨迹,我们专注于“城市车辆轨迹分析”。城市车辆轨迹分析提供了前所未有的机会,可以了解城市交通网络中的车辆运动模式,包括以用户为中心的旅行经验和系统范围的时空模式。城市车辆轨迹数据的时空特征在结构上相互关联,因此,许多先前的研究人员使用了各种方法来理解这种结构。特别是,由于其强大的函数近似和特征表示能力,深度学习模型是由于许多研究人员的注意。因此,本文的目的是开发基于深度学习的城市车辆轨迹分析模型,以更好地了解城市交通网络的移动模式。特别是,本文重点介绍了两项研究主题,具有很高的必要性,重要性和适用性:下一个位置预测,以及合成轨迹生成。在这项研究中,我们向城市车辆轨迹分析提供了各种新型模型,使用深度学习。
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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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旨在预测人群进入或离开某些地区的人群的预测是智能城市的一项基本任务。人群流数据的关键属性之一是周期性:一种按常规时间间隔发生的模式,例如每周模式。为了捕获这种周期性,现有研究要么将周期性的隐藏状态融合到网络中,以学习或将额外的定期策略应用于网络体系结构。在本文中,我们设计了一个新颖的定期残差学习网络(PRNET),以更好地建模人群流数据中的周期性。与现有方法不同,PRNET通过建模输入(上一个时期)和输出(未来时间段)之间的变化来将人群流动预测作为周期性的残差学习问题。与直接预测高度动态的人群流动相比,学习更多的固定偏差要容易得多,从而有助于模型训练。此外,学到的变化使网络能够在每个时间间隔内产生未来条件及其相应每周观察的残差,因此有助于更准确的多步骤预测。广泛的实验表明,PRNET可以轻松地集成到现有模型中,以增强其预测性能。
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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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由于流量大数据的增加,交通预测逐渐引起了研究人员的注意力。因此,如何在交通数据中挖掘复杂的时空相关性以预测交通状况更准确地成为难题。以前的作品组合图形卷积网络(GCNS)和具有深度序列模型的自我关注机制(例如,复发性神经网络),分别捕获时空相关性,忽略时间和空间的关系。此外,GCNS受到过平滑问题的限制,自我关注受到二次问题的限制,导致GCN缺乏全局代表能力,自我注意力效率低下捕获全球空间依赖性。在本文中,我们提出了一种新颖的交通预测深入学习模型,命名为多语境意识的时空关节线性关注(STJLA),其对时空关节图应用线性关注以捕获所有时空之间的全球依赖性节点有效。更具体地,STJLA利用静态结构上下文和动态语义上下文来提高模型性能。基于Node2VEC和单热编码的静态结构上下文丰富了时空位置信息。此外,基于多头扩散卷积网络的动态空间上下文增强了局部空间感知能力,并且基于GRU的动态时间上下文分别稳定了线性关注的序列位置信息。在两个现实世界交通数据集,英格兰和PEMSD7上的实验表明,我们的Stjla可以获得高达9.83%和3.08%,在最先进的基线上的衡量标准的准确性提高。
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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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准确的交通预测对于智能城市实现交通控制,路线计划和流动检测至关重要。尽管目前提出了许多时空方法,但这些方法在同步捕获流量数据的时空依赖性方面缺陷。此外,大多数方法忽略了随着流量数据的变化而产生的道路网络节点之间的动态变化相关性。我们建议基于神经网络的时空交互式动态图卷积网络(STIDGCN),以应对上述流量预测的挑战。具体而言,我们提出了一个交互式动态图卷积结构,该结构将序列划分为间隔,并通过交互式学习策略同步捕获流量数据的时空依赖性。交互式学习策略使StidGCN有效地预测。我们还提出了一个新颖的动态图卷积模块,以捕获由图生成器和融合图卷积组成的流量网络中动态变化的相关性。动态图卷积模块可以使用输入流量数据和预定义的图形结构来生成图形结构。然后将其与定义的自适应邻接矩阵融合,以生成动态邻接矩阵,该矩阵填充了预定义的图形结构,并模拟了道路网络中节点之间的动态关联的产生。在四个现实世界流量流数据集上进行的广泛实验表明,StidGCN的表现优于最先进的基线。
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Time series anomaly detection has applications in a wide range of research fields and applications, including manufacturing and healthcare. The presence of anomalies can indicate novel or unexpected events, such as production faults, system defects, or heart fluttering, and is therefore of particular interest. The large size and complex patterns of time series have led researchers to develop specialised deep learning models for detecting anomalous patterns. This survey focuses on providing structured and comprehensive state-of-the-art time series anomaly detection models through the use of deep learning. It providing a taxonomy based on the factors that divide anomaly detection models into different categories. Aside from describing the basic anomaly detection technique for each category, the advantages and limitations are also discussed. Furthermore, this study includes examples of deep anomaly detection in time series across various application domains in recent years. It finally summarises open issues in research and challenges faced while adopting deep anomaly detection models.
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交通预测是智能交通系统的问题(ITS),并为个人和公共机构是至关重要的。因此,研究高度重视应对准确预报交通系统的复杂的时空相关性。但是,有两个挑战:1)大多数流量预测研究主要集中在造型相邻传感器的相关性,而忽略远程传感器,例如,商务区有类似的时空模式的相关性; 2)使用静态邻接矩阵中曲线图的卷积网络(GCNs)的现有方法不足以反映在交通系统中的动态空间依赖性。此外,它采用自注意所有的传感器模型动态关联细粒度方法忽略道路网络分层信息,并有二次计算复杂性。在本文中,我们提出了一种新动态多图形卷积递归网络(DMGCRN),以解决上述问题,可以同时距离的空间相关性,结构的空间相关性,和所述时间相关性进行建模。那么,只使用基于距离的曲线图来捕获空间信息从节点是接近距离也构建了一个新潜曲线图,其编码的道路之间的相关性的结构来捕获空间信息从节点在结构上相似。此外,我们在不同的时间将每个传感器的邻居到粗粒区域,并且动态地分配不同的权重的每个区域。同时,我们整合动态多图卷积网络到门控重复单元(GRU)来捕获时间依赖性。三个真实世界的交通数据集大量的实验证明,我们提出的算法优于国家的最先进的基线。
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Accurate activity location prediction is a crucial component of many mobility applications and is particularly required to develop personalized, sustainable transportation systems. Despite the widespread adoption of deep learning models, next location prediction models lack a comprehensive discussion and integration of mobility-related spatio-temporal contexts. Here, we utilize a multi-head self-attentional (MHSA) neural network that learns location transition patterns from historical location visits, their visit time and activity duration, as well as their surrounding land use functions, to infer an individual's next location. Specifically, we adopt point-of-interest data and latent Dirichlet allocation for representing locations' land use contexts at multiple spatial scales, generate embedding vectors of the spatio-temporal features, and learn to predict the next location with an MHSA network. Through experiments on two large-scale GNSS tracking datasets, we demonstrate that the proposed model outperforms other state-of-the-art prediction models, and reveal the contribution of various spatio-temporal contexts to the model's performance. Moreover, we find that the model trained on population data achieves higher prediction performance with fewer parameters than individual-level models due to learning from collective movement patterns. We also reveal mobility conducted in the recent past and one week before has the largest influence on the current prediction, showing that learning from a subset of the historical mobility is sufficient to obtain an accurate location prediction result. We believe that the proposed model is vital for context-aware mobility prediction. The gained insights will help to understand location prediction models and promote their implementation for mobility applications.
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随着移动通信技术的快速发展,人类的移动轨迹由互联网服务提供商(ISP)和应用服务提供商(ASP)大规模收集。另一方面,知识图(kg)的上升范式为我们提供了一个有希望的解决方案,可以从大规模轨迹数据提取结构化的“知识”。在本文中,我们基于知识图技术专注于建模用户的时空移动模式,并根据从多个源以凝聚力的方式提取的“知识”,预测用户的未来运动。具体来说,我们提出了一种新型知识图中,即时空城市知识图(STKG),其中活动轨迹,场地的类别信息和时间信息都是由STKG中不同关系类型的事实共同建模。移动预测问题转换为知识图表在STKG中完成问题。此外,提出了一种具有精心设计的评分功能的复杂嵌入模型,以衡量STKG中的事实的合理性,以解决知识图形完成问题,这考虑了移动性模式的时间动态,并利用POI类别作为辅助信息和背景知识。广泛的评估确认我们模型在预测用户方面的高精度与最先进的算法相比,S'Mobility,即,提高了5.04%的准确性。此外,POI类别作为背景知识和辅助信息被证实通过在准确性方面提高了3.85%的性能,有助于提高。另外,实验表明,与现有方法相比,我们的所提出的方法通过将计算时间降低43.12%以上。
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人口级社会事件,如民事骚乱和犯罪,往往对我们的日常生活产生重大影响。预测此类事件对于决策和资源分配非常重要。由于缺乏关于事件发生的真实原因和潜在机制的知识,事件预测传统上具有挑战性。近年来,由于两个主要原因,研究事件预测研究取得了重大进展:(1)机器学习和深度学习算法的开发和(2)社交媒体,新闻来源,博客,经济等公共数据的可访问性指标和其他元数据源。软件/硬件技术中的数据的爆炸性增长导致了社会事件研究中的深度学习技巧的应用。本文致力于提供社会事件预测的深层学习技术的系统和全面概述。我们专注于两个社会事件的域名:\ Texit {Civil unrest}和\ texit {犯罪}。我们首先介绍事件预测问题如何作为机器学习预测任务制定。然后,我们总结了这些问题的数据资源,传统方法和最近的深度学习模型的发展。最后,我们讨论了社会事件预测中的挑战,并提出了一些有希望的未来研究方向。
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估计路径的旅行时间是智能运输系统的重要主题。它是现实世界应用的基础,例如交通监控,路线计划和出租车派遣。但是,为这样的数据驱动任务构建模型需要大量用户的旅行信息,这与其隐私直接相关,因此不太可能共享。数据所有者之间的非独立和相同分布的(非IID)轨迹数据也使一个预测模型变得极具挑战性,如果我们直接应用联合学习。最后,以前关于旅行时间估算的工作并未考虑道路的实时交通状态,我们认为这可以极大地影响预测。为了应对上述挑战,我们为移动用户组引入GOF-TTE,生成的在线联合学习框架以进行旅行时间估计,这是我)使用联合学习方法,允许在培训时将私人数据保存在客户端设备上,并设计设计和设计。所有客户共享的全球模型作为在线生成模型推断实时道路交通状态。 ii)除了在服务器上共享基本模型外,还针对每个客户调整了一个微调的个性化模型来研究其个人驾驶习惯,从而弥补了本地化全球模型预测的残余错误。 %iii)将全球模型设计为所有客户共享的在线生成模型,以推断实时道路交通状态。我们还对我们的框架采用了简单的隐私攻击,并实施了差异隐私机制,以进一步保证隐私安全。最后,我们对Didi Chengdu和Xi'an的两个现实世界公共出租车数据集进行了实验。实验结果证明了我们提出的框架的有效性。
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我们研究了具有动态,可能的周期性的流量的预测问题和区域之间的关节空间依赖关系。鉴于从时隙0到T-1的城市中区的聚合流入和流出流量,我们预测了任何区域的时间t的流量。该地区的现有技术通常以脱钩的方式考虑空间和时间依赖性,或者在具有大量超参数曲调的训练中是相当的计算密集。我们提出了ST-TIS,一种新颖,轻巧和准确的空间变压器,具有信息融合和区域采样进行交通预测。 ST-TIS将规范变压器与信息融合和区域采样延伸。信息融合模块捕获区域之间的复杂空间依赖关系。该区域采样模块是提高效率和预测精度,将计算复杂性切割为依赖性学习从$ O(n ^ 2)$到$ O(n \ sqrt {n})$,其中n是区域的数量。比最先进的模型的参数较少,我们模型的离线培训在调整和计算方面明显更快(培训时间和网络参数减少高达90±90 \%)。尽管存在这种培训效率,但大量实验表明,ST-TIS在网上预测中大幅度更准确,而不是最先进的方法(平均改善高达11 \%$ 11 \%$ ON MAPE上的$ 14 \%$ 14 \%$ 14 \%$ ON MAPE) 。
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通过深度学习(DL)大大扩展了数据驱动故障诊断模型的范围。然而,经典卷积和反复化结构具有计算效率和特征表示的缺陷,而基于注意机制的最新变压器架构尚未应用于该字段。为了解决这些问题,我们提出了一种新颖的时变电片(TFT)模型,其灵感来自序列加工的香草变压器大规模成功。特别是,我们设计了一个新的笨蛋和编码器模块,以从振动信号的时频表示(TFR)中提取有效抽象。在此基础上,本文提出了一种基于时变电片的新的端到端故障诊断框架。通过轴承实验数据集的案例研究,我们构建了最佳变压器结构并验证了其故障诊断性能。与基准模型和其他最先进的方法相比,证明了所提出的方法的优越性。
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Due to the issue that existing wireless sensor network (WSN)-based anomaly detection methods only consider and analyze temporal features, in this paper, a self-supervised learning-based anomaly node detection method based on an autoencoder is designed. This method integrates temporal WSN data flow feature extraction, spatial position feature extraction and intermodal WSN correlation feature extraction into the design of the autoencoder to make full use of the spatial and temporal information of the WSN for anomaly detection. First, a fully connected network is used to extract the temporal features of nodes by considering a single mode from a local spatial perspective. Second, a graph neural network (GNN) is used to introduce the WSN topology from a global spatial perspective for anomaly detection and extract the spatial and temporal features of the data flows of nodes and their neighbors by considering a single mode. Then, the adaptive fusion method involving weighted summation is used to extract the relevant features between different models. In addition, this paper introduces a gated recurrent unit (GRU) to solve the long-term dependence problem of the time dimension. Eventually, the reconstructed output of the decoder and the hidden layer representation of the autoencoder are fed into a fully connected network to calculate the anomaly probability of the current system. Since the spatial feature extraction operation is advanced, the designed method can be applied to the task of large-scale network anomaly detection by adding a clustering operation. Experiments show that the designed method outperforms the baselines, and the F1 score reaches 90.6%, which is 5.2% higher than those of the existing anomaly detection methods based on unsupervised reconstruction and prediction. Code and model are available at https://github.com/GuetYe/anomaly_detection/GLSL
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Deep learning approaches for spatio-temporal prediction problems such as crowd-flow prediction assumes data to be of fixed and regular shaped tensor and face challenges of handling irregular, sparse data tensor. This poses limitations in use-case scenarios such as predicting visit counts of individuals' for a given spatial area at a particular temporal resolution using raster/image format representation of the geographical region, since the movement patterns of an individual can be largely restricted and localized to a certain part of the raster. Additionally, current deep-learning approaches for solving such problem doesn't account for the geographical awareness of a region while modelling the spatio-temporal movement patterns of an individual. To address these limitations, there is a need to develop a novel strategy and modeling approach that can handle both sparse, irregular data while incorporating geo-awareness in the model. In this paper, we make use of quadtree as the data structure for representing the image and introduce a novel geo-aware enabled deep learning layer, GA-ConvLSTM that performs the convolution operation based on a novel geo-aware module based on quadtree data structure for incorporating spatial dependencies while maintaining the recurrent mechanism for accounting for temporal dependencies. We present this approach in the context of the problem of predicting spatial behaviors of an individual (e.g., frequent visits to specific locations) through deep-learning based predictive model, GADST-Predict. Experimental results on two GPS based trace data shows that the proposed method is effective in handling frequency visits over different use-cases with considerable high accuracy.
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