BCCLR:A Skeleton-Based Action Recognition with Graph Convolutional Network Combining Behavior Dependence and Context Clues

In recent years,skeleton-based action recognition has made great achievements in Computer Vision.A graph convolutional network(GCN)is effective for action recognition,modelling the human skeleton as a spatio-temporal graph.Most GCNs define the graph topology by physical relations of the human joints.However,this predefined graph ignores the spatial relationship between non-adjacent joint pairs in special actions and the behavior dependence between joint pairs,resulting in a low recognition rate for specific actions with implicit correlation between joint pairs.In addition,existing methods ignore the trend correlation between adjacent frames within an action and context clues,leading to erroneous action recognition with similar poses.Therefore,this study proposes a learnable GCN based on behavior dependence,which considers implicit joint correlation by constructing a dynamic learnable graph with extraction of specific behavior dependence of joint pairs.By using the weight relationship between the joint pairs,an adaptive model is constructed.It also designs a self-attention module to obtain their inter-frame topological relationship for exploring the context of actions.Combining the shared topology and the multi-head self-attention map,the module obtains the context-based clue topology to update the dynamic graph convolution,achieving accurate recognition of different actions with similar poses.Detailed experiments on public datasets demonstrate that the proposed method achieves better results and realizes higher quality representation of actions under various evaluation protocols compared to state-of-the-art methods.

Nonuniform Dependence on the Initial Data for Solutions of Conservation Laws

In this paper,we study systems of conservation laws in one space dimension.We prove that for classical solutions in Sobolev spaces H^(s),with s>3/2,the data-to-solution map is not uniformly continuous.Our results apply to all nonlinear scalar conservation laws and to nonlinear hyperbolic systems of two equations.

Trees species’ dispersal mode and habitat heterogeneity shape negative density dependence in a temperate forest

Conspecific negative density dependence(CNDD)is a potentially important mechanism in maintaining species diversity.While previous evidence showed habitat heterogeneity and species’dispersal modes affect the strength of CNDD at early life stages of trees(e.g.,seedlings),it remains unclear how they affect the strength of CNDD at later life stages.We examined the degree of spatial aggregation between saplings and trees for species dispersed by wind and gravity in four topographic habitats within a 25-ha temperate forest dynamic plot in the Qinling Mountains of central China.We used the replicated spatial point pattern(RSPP)analysis and bivariate paircorrelation function(PCF)to detect the spatial distribution of saplings around trees at two scales,15 and 50 m,respectively.Although the signal was not apparent across the whole study region(or 25-ha),it is distinct on isolated areas with specific characteristics,suggesting that these characteristics could be important factors in CNDD.Further,we found that the gravity-dispersed tree species experienced CNDD across habitats,while for wind-dispersed species CNDD was found in gully,terrace and low-ridge habitats.Our study suggests that neglecting the habitat heterogeneity and dispersal mode can distort the signal of CNDD and community assembly in temperate forests.

Understand anisotropy dependence of damage evolution and material removal during nanoscratch of MgF_(2) single crystals

To understand the anisotropy dependence of the damage evolution and material removal during the machining process of MgF_(2) single crystals,nanoscratch tests of MgF_(2) single crystals with different crystal planes and directions were systematically performed,and surface morphologies of the scratched grooves under different conditions were analyzed.The experimental results indicated that anisotropy considerably affected the damage evolution in the machining process of MgF_(2) single crystals.A stress field model induced by the scratch was developed by considering the anisotropy,which indicated that during the loading process,median cracks induced by the tensile stress initiated and propagated at the front of the indenter.Lateral cracks induced by tensile stress initiated and propagated on the subsurface during the unloading process.In addition,surface radial cracks induced by the tensile stress were easily generated during the unloading process.The stress change led to the deflection of the propagation direction of lateral cracks.Therefore,the lateral cracks propagated to the workpiece surface,resulting in brittle removal in the form of chunk chips.The plastic deformation parameter indicated that the more the slip systems were activated,the more easily the plastic deformation occurred.The cleavage fracture parameter indicated that the cracks propagated along the activated cleavage planes,and the brittle chunk removal was owing to the subsurface cleavage cracks propagating to the crystal surface.Under the same processing parameters,the scratch of the(001)crystal plane along the[100]crystal-orientation was found to be the most conducive to achieving plastic machining of MgF_(2) single crystals.The theoretical results agreed well with the experimental results,which will not only enhance the understanding of the anisotropy dependence of the damage evolution and removal process during the machining of MgF_(2) crystals,but also provide a theoretical foundation for achieving the high-efficiency and low-damage processing of anisotropic single crystals.

Optimization of extended warranty cost for multi-component systems with economic dependence based on group maintenance

During extended warranty(EW)period,maintenance events play a key role in controlling the product systems within normal operations.However,the modelling of failure process and maintenance optimization is complicated owing to the complex features of the product system,namely,components of the multi-component system are interdependent with each other in some form.For the purpose of optimizing the EW pricing decision of the multi-component system scientifically and rationally,taking the series multi-component system with economic dependence sold with EW policy as a research object,this paper optimizes the imperfect preventive maintenance(PM)strategy from the standpoint of EW cost.Taking into consideration adjusting the PM moments of the components in the system,a group maintenance model is developed,in which the system is repaired preventively in accordance with a specified PM base interval.In order to compare with the system EW cost before group maintenance,the system EW cost model before group maintenance is developed.Numerical example demonstrates that offering group maintenance programs can reduce EW cost of the system to a great extent,thereby reducing the EW price,which proves to be a win-win strategy to manufacturers and users.

A Hybrid Spatial Dependence Model Based on Radial Basis Function Neural Networks (RBFNN) and Random Forest (RF)

The majority of spatial data reveal some degree of spatial dependence. The term “spatial dependence” refers to the tendency for phenomena to be more similar when they occur close together than when they occur far apart in space. This property is ignored in machine learning (ML) for spatial domains of application. Most classical machine learning algorithms are generally inappropriate unless modified in some way to account for it. In this study, we proposed an approach that aimed to improve a ML model to detect the dependence without incorporating any spatial features in the learning process. To detect this dependence while also improving performance, a hybrid model was used based on two representative algorithms. In addition, cross-validation method was used to make the model stable. Furthermore, global moran’s I and local moran were used to capture the spatial dependence in the residuals. The results show that the HM has significant with a R2 of 99.91% performance compared to RBFNN and RF that have 74.22% and 82.26% as R2 respectively. With lower errors, the HM was able to achieve an average test error of 0.033% and a positive global moran’s of 0.12. We concluded that as the R2 value increases, the models become weaker in terms of capturing the dependence.

Estimating the Components of a Mixture of Extremal Distributions under Strong Dependence

In this paper, we provide a method based on quantiles to estimate the parameters of a finite mixture of Fréchet distributions, for a large sample of strongly dependent data. This is a situation that appears when dealing with environmental data and there was a real need of such method. We validate our approach by means of estimation and goodness-of-fit testing over simulated data, showing an accurate performance.

多重连接探针扩增技术在食品安全检测中的应用研究进展

阐述了多重连接探针扩增(MLPA)技术在食品过敏原检测、食品掺假、食源性致病菌和转基因食品检测中的应用现状,并对该技术在食品安全检测领域的发展趋势和挑战进行展望。

miR-567通过调控CDK8在NSCLC增殖、迁移和细胞周期中的作用及其临床相关性研究

目的探讨微小RNA(miR)-567通过调控周期蛋白依赖性激酶8(CDK8)在非小细胞肺癌(NSCLC)增殖、迁移和细胞周期中的作用及其临床相关性研究。方法收集40例NSCLC患者的肿瘤组织和临近癌旁组织,采用实时荧光定量PCR(qRT-PCR)检测miR-567和CDK8的表达。将miR-NC mimic、miR-567 mimic、oe-NC和oe-CDK8转染至A549和H1975细胞中,使用qRT-PCR检测miR-567和CDK8的表达,CCK-8法检测细胞增殖水平,Transwell法检测细胞迁移水平,流式细胞术检测细胞周期变化。通过荧光素酶报告基因实验检测miR-567与CDK8的靶向性。结果在NSCLC患者的肿瘤组织中,miR-567表达降低,而CDK8表达升高,二者呈负相关(P<0.05)。在A549和H1975细胞中,miR-567 mimic组相较于miR-NC mimic组,miR-567表达升高,CDK8表达降低,细胞增殖和迁移水平降低,细胞G1期比例升高,S期比例降低;miR-567 mimic组在正常型CDK8中,荧光强度低于miR-NC mimic组;miR-567 mimic+oe-CDK8组相较于miR-567 mimic+oe-NC组,CDK8表达升高,细胞增殖和迁移水平升高,细胞G1期比例降低,S期比例升高。结论miR-567通过靶向抑制CDK8表达,控制肿瘤细胞在S期阻滞,从而抑制NSCLC的增殖和迁移能力。

微服务系统服务依赖发现技术综述

微服务架构得到了广泛的部署与应用,提升了软件系统开发的效率,降低了系统更新与维护的成本,提高了系统的可扩展性.但微服务变更频繁、异构融合等特点使得微服务故障频发、其故障传播快且影响大,同时微服务间复杂的调用依赖关系或逻辑依赖关系又使得其故障难以被及时、准确地定位与诊断,对微服务架构系统的智能运维提出了挑战.服务依赖发现技术从系统运行时数据中识别并推断服务之间的调用依赖关系或逻辑依赖关系,构建服务依赖关系图,有助于在系统运行时及时、精准地发现与定位故障并诊断根因,也有利于如资源调度、变更管理等智能运维需求.首先就微服务系统中服务依赖发现问题进行分析,其次,从基于监控数据、系统日志数据、追踪数据等3类运行时数据的角度总结分析了服务依赖发现技术的技术现状;然后,以基于服务依赖关系图的故障根因定位、资源调度与变更管理等为例,讨论了服务依赖发现技术应用于智能运维的相关研究.最后,对服务依赖发现技术如何准确地发现调用依赖关系和逻辑依赖关系,如何利用服务依赖关系图进行变更治理进行了探讨并对未来的研究方向进行了展望.

酒依赖患者的腹侧苍白球改变及其与复饮的关系

目的:探讨酒依赖患者腹侧苍白球(VP)的体积变化及其与复饮的关系。方法:采用横断面与队列研究相结合的方法,选取符合美国精神障碍诊断与统计手册第4版(DSM-IV)酒精依赖综合征诊断标准的患者33例,在停酒14~28 d内进行头部磁共振成像检查,采用自制调查问卷、临床机构酒精戒断症状评定量表(CIWA)、酒精使用障碍筛查量表(AUDIT)进行评估,采用自制随访问卷评估半年内治疗结局。比较酒依赖组与对照组,复饮组与非复饮组间VP体积。结果:酒依赖组的VP体积小于正常对照组[(1749±492)mm^(3) vs.(2116±189)mm^(3),P<0.05],复饮组的VP体积较非复饮组大[(1956±452)mm^(3) vs.(1555±458)mm^(3),P<0.05]。结论:酒依赖患者的VP可能参与病理性奖赏环路功能,并与复饮有关。

再生粗骨料混凝土应力-应变关系

再生粗骨料混凝土应力-应变关系是实现其材料到结构力学分析的桥梁纽带,成为再生粗骨料混凝土结构基础理论的基石。介绍了作者团队多年来在再生粗骨料混凝土应力-应变关系方面取得的研究进展:采用模型化再生粗骨料方法,研究了复杂界面过渡区对再生粗骨料混凝土破坏行为的影响,揭示了再生粗骨料混凝土细观损伤本质与演化机理;从静力作用到动力作用,系统地开展了不同工况下再生粗骨料混凝土应力-应变行为试验研究,探明了载荷条件对再生粗骨料混凝土应力与变形的影响规律并建立了相适应的力学与数学模型;进一步考虑再生粗骨料性能时空变异性,发现了再生粗骨料混凝土力学响应的概率分布特征,提出了再生粗骨料混凝土随机损伤本构关系;基于获得的本构模型,完成了再生粗骨料混凝土构件时变可靠度分析和结构动力非线性分析,为再生粗骨料混凝土在实际工程中的安全应用提供了理论支撑;提炼了相关研究结论并对未来研究工作进行了展望。

机械通气脓毒症患者肺部超声重力依赖失充气表型与不良预后的相关性

目的分析脓毒症机械通气患者不同肺部超声表型的临床特征,探讨肺部超声重力依赖肺失充气表型对脓毒症机械通气患者不良预后的相关性。方法回顾性分析2019年4月至2020年10月四川大学华西医院重症医学科收治的机械通气脓毒症患者155例,按照28 d预后情况分为生存组(n=124)和死亡组(n=31),通过单因素和多因素Cox回顾分析肺部超声重力依赖失充气表型对患者28 d预后结局的影响。绘制Kaplan-Meier曲线分析重力依赖性和非重力依赖失充气表型与28 d预后生存的关系。结果单因素Cox回归分析发现,白细胞介素-6、SOFA评分、机械通气时间(h)、间质性失充气、实变性失充气、不张性失充气、存在重力依赖性失充气改变与患者28 d预后结局相关(P<0.05),进一步通过多因素Cox分析校正后发现存在间质性失充气肺部超声模式、机械通气时间和存在重力依赖性失充气改变与患者不良预后结局相关(P<0.05),重力依赖肺失充气表型的死亡风险是非重力依赖肺失充气表型的的2.003倍(HR=2.003,P=0.028,95%CI=1.112-6.387)。结论重力依赖肺失充气肺部超声表型可作为脓毒症机械通气患者不良预后的预测指标。

深空探测自主运行的一种可信性技术体系

未认知与不确定性是深空探测任务的基本特征.本文基于战略导向的体系化基础研究,建立了一种面向科学价值最大化的探测场景和以可靠性为核心技术基础的深空探测自主运行可信性技术体系.分析研究了深空探测场景下的可靠性概念;面向精确感知、最优计算、准确决策、快精准执行的目标要素,提出了深空探测自主运行的可信性体系框架以及“需求-认知-工程”总体技术架构;针对自主运行可信性的关键技术难点,开展了可靠性导向的多物理场、强耦合白盒建模,复杂网络故障传播机制分析,COTS元器件深空探测应用的高可靠保证,以及“模型+数据+知识”一体的融合机制分析等研究.对该技术体系的关键技术验证策略及其最小系统在卫星星座中的应用进行了验证,结果表明,所提出的技术体系具有较高的工程价值.

比较蛋白质组学揭示茉莉酸甲酯诱导的雷公藤甲素生物合成

目的:探索雷公藤甲素生物合成途径,以提高其产量或用于合成生物学异源生产。方法:使用无标记(lable-free)比较蛋白质组学对茉莉酸甲酯(MeJA)诱导的雷公藤悬浮细胞进行测序,通过京都基因与基因组百科全书(KEGG)、基因本体(GO)分析等方法,结合基因转录表达分析和基因体内功能研究,逐步筛选参与雷公藤甲素生物合成的功能基因。结果:MeJA诱导不同时间的样品组鉴定得到376个差异蛋白质,包括8个细胞色素P450酶(CYP450)、3个转录因子(TF)和2-氧戊二酸依赖的双加氧酶(2ODD)。其中CYP71BE89、CYP82AQ2和Tw2ODD基因在MeJA诱导及植物不同组织部位中,均与已知参与雷公藤甲素母核环化的二萜合酶TwTPS7(v2)和TwTPS27(v2)基因具有相似的表达模式,表明其可能与雷公藤甲素生物合成相关。进一步利用植物细胞体内功能研究,验证了CYP71BE89、CYP82AQ2和Tw2ODD基因干扰使雷公藤甲素积累分别降低了24.1%、41.4%和71.4%,表明了3个基因与雷公藤甲素生物合成直接相关。结论:利用比较蛋白质组学技术揭示了几种与雷公藤甲素生物合成相关的蛋白,进一步表征了雷公藤甲素生物合成与外源激素刺激之间的关系,并为发掘中药活性成分生物合成途径提供了一种有效方法。

京津多机场系统容量损失影响分析

全球范围内多机场系统数量和规模都在不断增长。由于终端区内有限资源的限制,邻近机场的运行存在一定的相关性,这导致多机场系统运行效率低下。为了估计多机场运行产生的限制,以北京终端区为例提出一种统计分析框架对多机场系统的容量损失进行整体分析。首先,根据理论容量模型分别计算出北京终端区各机场的理论容量,并进一步确定各机场独立运行下的实际容量;其次,以北京终端区的历史运行数据为基础,估计出3个机场及终端区系统的具有鲁棒性的Pareto容量包络曲线;最后,基于独立运行容量与相关运行容量量化出终端区各机场及多机场系统的实际容量损失。为进一步提高多机场终端区的运行效率提供建议与参考。

深部直墙半圆拱巷道围岩时效损伤劣化特征与动态补强技术

随着煤矿开采向深部逐渐延伸,巷道的大变形和长时间持续流变特性已成为支护中极具挑战的课题之一。为了探究深部巷道围岩损伤劣化的时效特征及动态补强技术,基于实验室试验,并结合理论分析、数值模拟及现场工业试验进行了研究。研究结果表明:(1)基于Laplace逆变换推导出圆形轴对称巷道的变形规律解析解,结合理论分析、非圆形巷道等效变换和现场试验确定塑性区半径为1.5~2.1m,进一步得到直墙半圆拱巷道时效变形解析解;(2)基于弹性与弹塑性巷道模型,采用能量耗散表征了围岩损伤劣化的时效特征与塑性区演化趋势,并提出了一次支护的时机;(3)阐明了围岩在一次支护后的时效性损伤劣化的演化趋势,基于垂直应力峰值比率,提出了二次支护方案与时机,进一步分析围岩剪应力与垂直应力,确定了二次支护锚杆的长度为3.0 m,支护时机为40~70 d。研究结果可为深部煤矿巷道的设计与维护提供理论依据和实践指导。

活性依赖性神经保护蛋白在肿瘤中的研究进展

活性依赖性神经保护蛋白(ADNP)是一种转录因子。近些年来研究发现,ADNP具有染色质重塑、细胞周期与增殖调控、DNA损伤与修复、细胞运动与转移、化疗耐药等肿瘤相关生物学功能,在多种肿瘤中均存在不同程度的突变及异常表达,与肿瘤的发生、发展密切相关。本文综述了ADNP的分子结构、功能特点及其在多种肿瘤发生、发展中的研究进展,旨在为肿瘤的诊治研究方向提供新思路。

融合情感语义与句法结构的中文开放域事理图谱构建研究

为解决大规模开放域事理图谱构建过程中缺少标注数据以及事件类型未知导致的限定域事理图谱构建方法难以迁移的问题,利用规则匹配方法高效识别开放域文本中包含的多种事件逻辑关系,融合情感语义与句法结构信息分析提高事件抽取准确性,以更好完成事理图谱的构建任务。首先,总结并扩展因果、顺承、条件、转折等多种逻辑关系抽取模板,并基于规则模板、依存句法信息筛选逻辑关系事件句;其次,创新性地引入情感语义分析方法,在句法结构信息的基础上,通过捕获事件及事件间关系的情感语义精准识别事件类型,进而抽取事件论元;再次,计算语义相似度,进行事件融合,构建<前序事件,事件逻辑关系,后序事件>三元组,得到事件事理图谱,并进一步进行事件泛化以构建抽象事理图谱;最后,以事件发展较完整的“2022年猴痘事件”为数据源,通过实证分析证明开放域事理图谱构建方法可以实现不同类型事件的识别、事件间逻辑关系的揭露,其有效性、可行性得到验证。研究不仅弥补了现有事理图谱构建理论的不足,也为决策支持、事件发展预测等提供有力的数据支持。

装配式建筑结构顶升逆作法原理与技术发展

顶升逆作法综合了顶升和逆作法两种技术的不同特性,是一种在邻近地面对建筑逐层建造并逐层顶升的新型建造工艺。通过对顶升各阶段的原理分析,结合强时变结构特点,对顶升点选择等关键技术进行研究,分析了竖向顶升位移不同步工况下的结构受力机理,厘清了装配式建筑结构顶升逆作法的受力特点,梳理了现有的相关配套技术,指出了目前装配式建筑结构顶升逆作法待解决的技术难题。针对新型建造工艺的强时变特征,提出了结合数字孪生和人工智能两种技术进行智能调控的发展趋势,构建了面向减碳优化的综合目标函数,并通过算例证明合理的顶升方案对减少建造阶段构件内力的作用。结果表明:依托装配式建筑结构顶升逆作法原理,采用机械化施工取代人工作业、大重量顶升替换高空吊运,减少设备的层间转运和材料的竖向运输,能够在提高施工建造效率的同时,将工艺流程控制在临近地面的有效高度范围内,有望降低环境影响、减少碳排放、提高建筑结构在未来服役末期的资源化可行性,助力建筑业绿色低碳发展。