Spatial-temporal

时空
  • 文章类型: Journal Article
    最近,图神经网络(GNNs)在脑网络自动分类任务中得到了广泛的应用,由于它们能够直接捕获非欧几里得结构中的关键信息。然而,这个领域仍然存在两个主要挑战。首先,在临床神经医学领域,来自大脑区域的信号不可避免地受到来自生理或外部因素的噪音的污染。大脑网络的构建在很大程度上依赖于大脑区域内的设定阈值和特征信息,使其容易受到将这些噪声并入大脑拓扑结构的影响。此外,人工构建的脑网络相邻结构的静态特性限制了脑拓扑的实时变化。第二,基于GNN的主流方法倾向于只关注捕获最近邻节点的信息交互,俯瞰高阶拓扑特征。为了应对这些挑战,我们提出了一种自适应无监督的时空动态超图信息瓶颈(ST-DHIB)框架,用于动态优化大脑网络。具体来说,采用信息论的观点,图信息瓶颈(GIB)用于纯化图结构,并动态更新处理后的输入大脑信号。从图论的角度来看,我们利用设计的超图神经网络(HGNN)和Bi-LSTM来捕获大脑通道之间的高阶时空关联。已经在两个可用的数据集上进行了全面的患者特异性和跨患者实验。结果证明了所提出的框架的进步和推广。
    Recently, Graph Neural Networks (GNNs) have gained widespread application in automatic brain network classification tasks, owing to their ability to directly capture crucial information in non-Euclidean structures. However, two primary challenges persist in this domain. First, within the realm of clinical neuro-medicine, signals from cerebral regions are inevitably contaminated with noise stemming from physiological or external factors. The construction of brain networks heavily relies on set thresholds and feature information within brain regions, making it susceptible to the incorporation of such noises into the brain topology. Additionally, the static nature of the artificially constructed brain network\'s adjacent structure restricts real-time changes in brain topology. Second, mainstream GNN-based approaches tend to focus solely on capturing information interactions of nearest neighbor nodes, overlooking high-order topology features. In response to these challenges, we propose an adaptive unsupervised Spatial-Temporal Dynamic Hypergraph Information Bottleneck (ST-DHIB) framework for dynamically optimizing brain networks. Specifically, adopting an information theory perspective, Graph Information Bottleneck (GIB) is employed for purifying graph structure, and dynamically updating the processed input brain signals. From a graph theory standpoint, we utilize the designed Hypergraph Neural Network (HGNN) and Bi-LSTM to capture higher-order spatial-temporal context associations among brain channels. Comprehensive patient-specific and cross-patient experiments have been conducted on two available datasets. The results demonstrate the advancement and generalization of the proposed framework.
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  • 文章类型: Journal Article
    空气污染是首要问题,每年导致约700万人过早死亡,与交通相关的来源占排放量的23%-45%。虽然一些研究已经调查了车辆排放模型,它们要么过时,要么专注于特定的数据驱动模型。本文系统地回顾了汽车排放预测模型,将传统方法与数据驱动的排放模型进行比较。传统的排放模型可以分为平均速度,模态,和其他型号,注意到他们依赖于经验假设和参数,这些假设和参数可能并不普遍适用。相比之下,我们深入研究了利用测功机和道路测试数据进行时间序列和时空预测的数据驱动模型。这些模型的应用在各种场景中进行了讨论,突出进步和差距。我们观察到传统模型,主要估算研究区域的总交通排放量,缺乏对量身定制的决策至关重要的微观细节。道路排放模型准确性与输入数据质量之间的直接联系在分解道路车辆排放清单方面提出了挑战。由于独特的运输工具,交通车队组件,和模式,探索减排政策在特定城市或地区的效果迫在眉睫。车辆特性,环境条件,交通场景,预测尺度是共同的影响因素,而瞬时驱动曲线在模型校准中被证明是有效的。在数据驱动模型中,ANN在估算低功率柴油发动机的排放和性能方面表现出色,误差不超过5%。然而,没有单一的数据驱动方法在预测所有污染物方面表现优异。此外,利用LSTM的集成方法,GRU,和RNN优于单个模型。考虑到路网的固有连通性和车辆排放的时空变化模式,提高预测精度。GCN是一种基于遥感数据捕获时空关系的新兴方法。此外,已经进行了有限的数据驱动研究来预测颗粒物的排放,城市污染的主要贡献者,呼吁对未来的研究给予更多关注。
    Air pollution is a primary concern, causing around 7 million premature deaths annually, with traffic-related sources contributing 23 %-45 % of emissions. While several studies have surveyed vehicle emission models, they are either outdated or focus on specific data-driven models. This paper systematically reviews vehicle emission prediction models, comparing traditional approaches with data-driven emission models. The traditional emission models can be divided into average-speed, modal, and other models, noting their reliance on empirical assumptions and parameters that may not be universally applicable. In contrast, we delve into data-driven models utilizing dynamometer and on-road test data for time-series and spatial-temporal predictions. The application of these models is discussed across various scenarios, highlighting the progress and gap. We observed that traditional models, primarily estimating total traffic emissions in study regions, lack micro-level detail crucial for tailored decisions. The direct link between road emission model accuracy and input data quality poses challenges in disaggregating on-road vehicle emission inventories. Due to unique transportation instruments, traffic fleet components, and patterns, exploring the effects of emission-reduction policies in specific cities or regions is urgent. Vehicle characteristics, environmental conditions, traffic scenarios, and prediction scales are common effect factors, while instantaneous driving profiles prove effective in model calibration. In data-driven models, ANN outperforms in estimating emissions and performance of low-power diesel engines with errors not exceeding 5 %. However, no single data-driven method performed excellently in predicting all pollutants. Besides, integrated methods utilizing LSTM, GRU, and RNN outperform individual models. To enhance prediction accuracy considering the inherent connectivity of road networks and spatiotemporal variation patterns of vehicle emissions, GCN is an emerging approach for capturing spatial-temporal relationships based on remote sensing data. Moreover, limited data-driven studies have been performed to forecast particle matter emissions, the main contributors to urban pollution, calling for more attention for future research.
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  • 文章类型: Journal Article
    我们研究视频绘画,其目的是从损坏的帧恢复逼真的纹理。通过将其他帧作为参考,从而可以将相关纹理转移到损坏的帧,从而取得了最新进展。然而,现有的视频修复方法忽略了模型提取信息和重建内容的能力,导致无法重建应准确转移的纹理。在本文中,我们提出了一种新颖有效的时空纹理变换网络(STTTN)用于视频修补。STTTN由六个紧密相关的模块组成,这些模块针对视频修补任务进行了优化:特征相似性度量,以实现更准确的帧预修复,具有强大信息提取能力的编码器,用于查找相关性的嵌入模块,粗低频特征传递,精化高频特征传递,和解码器具有准确的内容重建能力。这样的设计鼓励跨输入和参考帧的联合特征学习。为了证明该模型的先进性和有效性,我们通过使用标准的固定掩模和更真实的移动对象掩模,对多个数据集进行全面的消融学习和定性和定量实验。良好的实验结果证明了STTTN的真实性和可靠性。
    We study video inpainting, which aims to recover realistic textures from damaged frames. Recent progress has been made by taking other frames as references so that relevant textures can be transferred to damaged frames. However, existing video inpainting approaches neglect the ability of the model to extract information and reconstruct the content, resulting in the inability to reconstruct the textures that should be transferred accurately. In this paper, we propose a novel and effective spatial-temporal texture transformer network (STTTN) for video inpainting. STTTN consists of six closely related modules optimized for video inpainting tasks: feature similarity measure for more accurate frame pre-repair, an encoder with strong information extraction ability, embedding module for finding a correlation, coarse low-frequency feature transfer, refinement high-frequency feature transfer, and decoder with accurate content reconstruction ability. Such a design encourages joint feature learning across the input and reference frames. To demonstrate the advancedness and effectiveness of the proposed model, we conduct comprehensive ablation learning and qualitative and quantitative experiments on multiple datasets by using standard stationary masks and more realistic moving object masks. The excellent experimental results demonstrate the authenticity and reliability of the STTTN.
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  • 文章类型: Journal Article
    COVID-19大流行对人类健康和社会经济产生了重大影响。一些研究检查了与COVID-19相关的健康风险因素的时空格局,但尚未充分考虑人口流动溢出效应。在本文中,开发了基于人口流的时空特征向量滤波模型(FLOW-ESTF),以同时考虑时空模式和人口流连通性。提出的FLOW-ESTF方法有效地提高了模型预测精度,这可以帮助政府了解感染风险水平并制定适当的控制政策。选定的人口流动时空特征向量对建模贡献最大,相应特征向量集的可视化有助于探索潜在的时空模式和大流行传播节点。模型系数可以反映健康风险因素如何有助于建立州级COVID-19每周增加病例的模型,以及它们的影响如何随时间变化,这可以帮助人们和政府更好地意识到潜在的健康风险,并在不同阶段调整控制措施。提取的人口流动时空特征向量不仅代表了人口流动的影响及其溢出效应,而且还代表了一些可能被忽略的健康风险因素。这可以为解决COVID-19建模中的空间和时间自相关问题提供有效的途径,并且可以直观地发现潜在的空间模式,这将部分弥补潜在风险变量考虑不足和数据缺失的问题。
    The COVID-19 pandemic has had great impact on human health and social economy. Several studies examined spatial and temporal patterns of health risk factors associated with COVID-19, but population flow spillover effect has not been sufficiently considered. In this paper, a population flow-based spatial-temporal eigenvector filtering model (FLOW-ESTF) was developed to consider spatial-temporal patterns and population flow connectivity simultaneously. The proposed FLOW-ESTF method efficiently improved model prediction accuracy, which could help the government aware of the infection risk level and to make suitable control policies. The selected population flow spatial-temporal eigenvector contributed most to modeling and the visualization of corresponding eigenvector set helped to explore the underlying spatial-temporal patterns and pandemic transmission nodes. The model coefficients could reflect how health risk factors contribute the modeling of state-level COVID-19 weekly increased cases and how their influence changed through time, which could help people and government to better aware the potential health risks and to adjust control measures at different stage. The extracted population flow spatial-temporal eigenvector not only represents influence of population flow and its spillover effects but also represents some possible omitted health risk factors. This could provide an efficient path to solve the problem of spatial and temporal autocorrelation in COVID-19 modeling and an intuitive way to discover underlying spatial patterns, which will partially compensate for the problems of insufficient consideration of potential risk variables and missing data.
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  • 文章类型: Journal Article
    阿巴的地形,天气,气候使它容易发生山体滑坡,泥石流,和其他自然灾害,这限制了经济和社会的增长。评估和提高区域复原力对于减轻自然灾害和实现可持续发展至关重要。在本文中,采用熵权法将现有框架与地点抗灾能力(DROP)模型相结合,计算了阿坝2010-2018年多灾害压力下的抗灾能力。然后基于变异系数和探索性空间数据分析(ESDA)分析时空特征。最后,偏最小二乘(PLS)回归用于识别对灾害弹性的关键影响。结果表明:(1)阿坝的抗灾能力在2010年至2018年期间有所增加,但在2013年和2017年由于大规模灾害而有所下降。(2)各阿坝县发展水平存在时空差异。从2010年到2016年,东部和西部的低低(LL)聚集显示出明显的正空间关联和高(HH)聚集。然后空间聚集在2017年后减弱。本文提出整合区域发展,加强发展水平建设,并强调阿坝的灾害管理。
    Aba\'s topography, weather, and climate make it prone to landslides, mudslides, and other natural disasters, which limit economic and social growth. Assessing and improving regional resilience is important to mitigate natural disasters and achieve sustainable development. In this paper, the entropy weight method is used to calculate the resilience of Aba under multi-hazard stress from 2010 to 2018 by combining the existing framework with the disaster resilience of the place (DROP) model. Then spatial-temporal characteristics are analyzed based on the coefficient of variation and exploratory spatial data analysis (ESDA). Finally, partial least squares (PLS) regression is used to identify the key influences on disaster resilience. The results show that (1) the disaster resilience in Aba increased from 2010 to 2018 but dropped in 2013 and 2017 due to large-scale disasters. (2) There are temporal and spatial differences in the level of development in each of the Aba counties. From 2010 to 2016, disaster resilience shows a significant positive spatial association and high-high (HH) aggregation in the east and low-low (LL) aggregation in the west. Then the spatial aggregation weakened after 2017. This paper proposes integrating regional development, strengthening the development level building, and emphasizing disaster management for Aba.
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  • 文章类型: Journal Article
    目的:明确肌萎缩侧索硬化症(ALS)的传播模式具有挑战性,但了解这些对个体预测和临床试验设计有意义.然而,缺乏这方面的系统知识。这项研究的目的是表征ALS中传播模式的时空特征,并评估传播模式与生存之间的关联。
    方法:833名ALS患者的队列,分析了在2018年1月至2019年12月之间诊断并随访至2021年8月。传播模式的空间和时间特征是根据所涉及的功能区域(Bulbar,子宫颈,胸/呼吸和腰部)按时间顺序。在涉及至少三个功能区的患者中鉴定了最终的传播模式。进行Kaplan-Meier分析和Cox回归分析。
    结果:在21.2个月的中位随访期间,在657例患者中确定了19种最终的传播模式(78.9%)。在生存分析中,我们发现呼吸功能区参与得越早,死亡风险越高(时间顺序:第1:危险比[HR],3.35,95%置信区间[CI]1.23-9.15;第二:HR2.45,95%CI1.55-3.87;第三:HR1.94,95%CI1.52-2.49),调整年龄,性别,诊断延迟,修订后的ALS功能评定量表评分,认知障碍和利鲁唑。受累区域间隔时间越短是一个独立的不良预后因素。
    结论:ALS的传播模式各不相同。呼吸区域参与的顺序以及功能区参与之间的间隔时间是预后的预测因子。
    OBJECTIVE: Clarification of propagation patterns in amyotrophic lateral sclerosis (ALS) is challenging, but understanding these has implications for individual prognostication and clinical trial design. However, systematic knowledge in this area is lacking. The aim of this study was to characterize the spatial and temporal features of propagation patterns in ALS, and to evaluate the association between propagation patterns and survival.
    METHODS: A cohort of 833 patients with ALS, diagnosed between January 2018 and December 2019 and followed to August 2021, was analysed. Spatial and temporal features of propagation patterns were determined based on the involved functional regions (bulbar, cervical, thoracic/respiratory and lumbar) in time order. The final propagation pattern was identified in patients with at least three functional regions involved. Kaplan-Meier analysis and Cox regression analysis were performed.
    RESULTS: During a median follow-up of 21.2 months, 19 final propagation patterns were identified in 657 patients (78.9%). In survival analysis, we found that the earlier the respiratory functional region becomes involved, the higher the risk of death (time order: 1st: hazard ratio [HR], 3.35, 95% confidence interval [CI] 1.23-9.15; 2nd: HR 2.45, 95% CI 1.55-3.87; 3rd: HR 1.94, 95% CI 1.52-2.49), adjusting for age, sex, diagnostic delay, revised ALS Functional Rating Scale score, cognitive impairment and riluzole. Shorter interval time between involved regions was an independent adverse prognostic factor.
    CONCLUSIONS: The propagation patterns of ALS are varied. The order in which the respiratory region becomes involved and the interval time between involvement of functional regions are predictors for prognosis.
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  • 文章类型: Journal Article
    目的:这是一项长期的回顾性研究,为了解武威市1995-2016年肝硬化的时空变化趋势,找出高发地区。为制定武威市肝硬化综合防治策略提供理论依据。方法:这里,我们提取了在武威市12家哨点医院接受治疗的肝硬化患者的病历数据。我们使用SAS和Joinpoint回归程序进行数据分析,SaTScan9.4软件,用于聚类区域检测,和ArcGIS10.2软件进行地理分布制图。结果:3308例肝硬化患者(平均年龄,55.34年)纳入本研究,15.9%的人年龄在50-54岁之间。大多数是男性(2716,65.8%),性别比为1.92:1,按职业划分的农民(1369,60.3%)。基本社会医疗保险制度覆盖了1271名患者(63%)的医疗费用。1995-2016年进行的Joinpoint回归分析显示,在2010年,2013年和2016年,标准化肝硬化率[平均年度变化百分比(AAPC)=16.7%(95%CI,10.2-23.5%)]增加了三个连接点。1995年至2010年的年度百分比变化(APC)为11.13%(95%CI:6.5-16.0),2010年至2013年的APC为66.48%(95%CI:16.0-138.9);相反,从2013年到2016年,APC为4.4%(95%CI,-7.5-17.8%).洪沙岗镇平均发病率最高。2010年以后,各乡镇的发病率逐渐上升。结果显示,在每个乡镇,肝硬化发病率有一定的空间聚集性,且是非随机的.武威市75个乡镇有4个肝硬化集群。数据收集自2011年至2016年。结论:1995-2016年武威市肝硬化发病率仍呈逐年上升趋势,但自2013年以来增速放缓。在武威,女性患者的肝硬化标准化率稳步上升,并且比男性患者快。有必要加强诊断,治疗,预防,肝硬化相关疾病的防治措施。空间扫描的结果,基本空间分布,聚合时间,和时间趋势分析是一致的。
    Objectives: This was a long-term retrospective study, aiming to understand the temporal and spatial trend of cirrhosis in Wuwei from 1995 to 2016, explore its spatio-temporal aggregation, and find out the high incidence areas. To provide theoretical basis for the formulation of comprehensive prevention and treatment strategy of cirrhosis in Wuwei. Methods: Herein, we extracted data of cirrhosis patients who were treated in 12 sentinel hospitals in Wuwei from their medical records. We used SAS and Joinpoint Regression Program for data analysis, SaTScan 9.4 software for clustering area detection, and ArcGIS 10.2 software for geographical distribution mapping. Results: Among 3308 patients with liver cirrhosis (average age, 55.34 years) included in this study, 15.9% were aged 50-54 years. The majority were men (2716, 65.8%), with a sex ratio of 1.92:1 and peasants by occupation (1369, 60.3%). The basic social medical insurance system covered the healthcare costs of 1271 patients (63%). A Joinpoint regression analysis done for 1995-2016 revealed an increase in the standardized cirrhosis rate [average annual percent change (AAPC) = 16.7% (95% CI, 10.2-23.5%)] with three joinpoints in 2010, 2013, and 2016. The annual percent change (APC) from 1995 to 2010 was 11.13% (95% CI: 6.5-16.0), and APC from 2010 to 2013 was 66.48% (95% CI:16.0-138.9); conversely, from 2013 to 2016, APC was 4.4% (95% CI, -7.5-17.8%). Hongshagang Town showed the highest average incidence. Each township showed a gradual increase in the incidence after 2010. The results revealed that in each township, liver cirrhosis incidence had some spatial aggregation and was nonrandom. Four liver cirrhosis clusters were noted in 75 townships in Wuwei. Data were gathered from 2011 to 2016. Conclusions: From 1995 to 2016, the incidence of cirrhosis in Wuwei still showed an increasing trend, but the growth rate slowed down since 2013. In Wuwei, the rate of standardization of cirrhosis in female patients increased steadily and faster than in male patients. It is necessary to strengthen the diagnosis, treatment, prevention, and control measures of cirrhosis-related diseases. The results of spatial scanning, basic spatial distribution, aggregation time, and time trend analysis were consistent.
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  • 文章类型: Journal Article
    基于骨架的人体动作识别已经取得了很大的进展,特别是随着图卷积网络(GCN)的发展。最重要的工作是ST-GCN,从骨架序列中自动学习空间和时间模式。然而,这种方法仍然存在一些缺陷:只有短程相关性得到重视,由于图卷积的接受场有限。然而,长期依赖对于识别人类行为至关重要。在这项工作中,我们建议使用时空相对变换器(ST-RT)来克服这些缺陷。通过引入中继节点,ST-RT避免了变压器架构,打破了空间上固有的骨架拓扑和时间维度上骨架序列的顺序。此外,我们挖掘运动中包含的不同尺度的动态信息。最后,四个ST-RT,从四种骨架序列中提取时空特征,融合形成最终模型,多流时空相对变换器(MSST-RT),以提高性能。广泛的实验在基于骨架的动作识别的三个基准上评估了所提出的方法:NTURGBD,NTURGB+D120和UAV-Human。结果表明,MSST-RT在性能方面与SOTA相当。
    Skeleton-based human action recognition has made great progress, especially with the development of a graph convolution network (GCN). The most important work is ST-GCN, which automatically learns both spatial and temporal patterns from skeleton sequences. However, this method still has some imperfections: only short-range correlations are appreciated, due to the limited receptive field of graph convolution. However, long-range dependence is essential for recognizing human action. In this work, we propose the use of a spatial-temporal relative transformer (ST-RT) to overcome these defects. Through introducing relay nodes, ST-RT avoids the transformer architecture, breaking the inherent skeleton topology in spatial and the order of skeleton sequence in temporal dimensions. Furthermore, we mine the dynamic information contained in motion at different scales. Finally, four ST-RTs, which extract spatial-temporal features from four kinds of skeleton sequence, are fused to form the final model, multi-stream spatial-temporal relative transformer (MSST-RT), to enhance performance. Extensive experiments evaluate the proposed methods on three benchmarks for skeleton-based action recognition: NTU RGB+D, NTU RGB+D 120 and UAV-Human. The results demonstrate that MSST-RT is on par with SOTA in terms of performance.
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  • 文章类型: Journal Article
    Geometry-based properties and characteristics of drug molecules play an important role in drug development for virtual screening in computational chemistry. The 3D characteristics of molecules largely determine the properties of the drug and the binding characteristics of the target. However, most of the previous studies focused on 1D or 2D molecular descriptors while ignoring the 3D topological structure, thereby degrading the performance of molecule-related prediction. Because it is very time-consuming to use dynamics to simulate molecular 3D conformer, we aim to use machine learning to represent 3D molecules by using the generated 3D molecular coordinates from the 2D structure.
    We proposed Drug3D-Net, a novel deep neural network architecture based on the spatial geometric structure of molecules for predicting molecular properties. It is grid-based 3D convolutional neural network with spatial-temporal gated attention module, which can extract the geometric features for molecular prediction tasks in the process of convolution. The effectiveness of Drug3D-Net is verified on the public molecular datasets. Compared with other deep learning methods, Drug3D-Net shows superior performance in predicting molecular properties and biochemical activities.
    https://github.com/anny0316/Drug3D-Net.
    Supplementary data are available online at https://academic.oup.com/bib.
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  • 文章类型: Journal Article
    Exploring the spatial patterns and temporal dynamics of human brain activity has been of great interest, in the quest to better understand connectome-scale brain networks. Though modeling spatial and temporal patterns of functional brain networks have been researched for a long time, the development of a unified and simultaneous spatial-temporal model has yet to be realized. For instance, although some deep learning methods have been proposed recently in order to model functional brain networks, most of them can only represent either spatial or temporal perspective of functional Magnetic Resonance Imaging (fMRI) data and rarely model both domains simultaneously. Due to the recent success in applying sequential auto-encoders for brain decoding, in this paper, we propose a deep sparse recurrent auto-encoder (DSRAE) to be applied unsupervised to learn spatial patterns and temporal fluctuations of brain networks at the same time. The proposed DSRAE was evaluated and validated based on three tasks of the publicly available Human Connectome Project (HCP) fMRI dataset, resulting with promising evidence. To the best of our knowledge, the proposed DSRAE is among the early efforts in developing unified models that can extract connectome-scale spatial-temporal networks from 4D fMRI data simultaneously.
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