An integrated emotional and physiological assessment for VR-based active shooter incident experiments

Unfortunately, active shooter incidents are on the rise in the United States. With the recent technological advancements, virtual reality (VR) experiments could serve as an effective method to prepare civilians and law enforcement personnel for such scenarios. However, for VR experiments to be effective for active shooter training and research, such experiments must be able to evoke emotional and physiological responses as live active shooter drills and events do. The objective of this study is thus to test the effectiveness of an active shooter VR experiment on emotional and physiological responses. Additionally, we consider different locomotion techniques (i.e., walk-in-place and controller) and explore their impact on users’ sense of presence. The results suggest that the VR active shooter experiment in this study can induce emotional arousal and increase heart rate of the participants immersed in the virtual environment. Furthermore, compared to the controller, the walk-in-place technique resulted in a higher emotional arousal in terms of negative emotions and a stronger sense of presence. The study presents a foundation for future active shooter experiments as it supports the ecological validity using VR for active shooter incident related work for the purposes of training or research.     

Evolutionary digital twin: A new approach for intelligent industrial product development

To fulfill increasingly difficult and demanding tasks in the ever-changing complex world, intelligent industrial products are to be developed with higher flexibility and adaptability. Digital twin (DT) brings about a possible means, due to its ability to provide candidate behavior adjustments based on received “feedbacks” from its physical part. However, such candidate adjustments are deterministic, and thus lack of flexibility and adaptability. To address such problem, in this paper an extended concept – evolutionary digital twin (EDT) and an EDT-based new mode for intelligent industrial product development has been proposed. With our proposed EDT, a more precise approximated model of the physical world could be established through supervised learning, based on which the collaborative exploration for optimal policies via parallel simulation in multiple cyberspaces could be performed through reinforcement learning. Hence, more flexibility and adaptability could be brought to industrial products through machine learning (such as supervised learning and reinforcement learning) based self-evolution. As a primary verification of the effectiveness of our proposed approach, a case study has been carried out. The experimental results have well confirmed the effectiveness of our EDT based development mode.     

面向交通流量预测的时空超关系图卷积网络

交通流量预测是智能交通系统中的重要研究课题,然而,交通对象（如站点、传感器）之间存在的复杂局部时空关系使得这项研究颇具挑战。尽管以往的一些研究将流量预测问题转化为一个时空图预测问题从而取得了较大的进展,但是它们忽略了交通对象们跨时空维度的直接关联性。目前仍缺乏一种全面建模局部时空关系的方法。针对这一问题,首先提出一种新颖的时空超图建模方案,通过构造一种时空超关系来全面地建模复杂的局部时空关系;然后提出一种时空超关系图卷积网络（STHGCN）预测模型来捕获这些关系用于交通流量预测。在四个公开交通数据集上进行了大量对比实验,结果表明,相比ASTGCN、时空同步图卷积网络（STSGCN）等时空预测模型,STHGCN在均方根误差（RMSE）、平均绝对误差（MAE）、平均绝对百分比误差（MAPE）这三个评价指标上均取得了更优的结果,不同模型运行时间的对比结果也表明,STHGCN有着更高的推理速度。     

框支密肋复合墙体拟静力试验研究

为研究底部大空间框支密肋复合墙结构的抗震性能,结合新型斜交肋格密肋复合墙板结构,进行2榀底部框架-剪力墙上部密肋复合墙体结构1/2比例模型拟静力试验.分析正交肋格和斜交肋格框支密肋复合墙体在低周反复荷载作用下的破坏过程、传力机理,探讨结构层间位移滞回特性,各构件钢筋的荷载-应变曲线,墙体的残余变形率.试验结果表明:框支密肋复合墙结构抗震性能优越,墙板独特的斜交式肋格构造形式有效提高结构的延性、变形性能,抗倒塌能力和可修复性.     

活性粉末混凝土冻融循环前后NaCl溶液的吸入特性

为更好地理解混凝土盐冻破坏机理,研究了NaCl溶液中NaCl质量分数对活性粉末混凝土溶液吸入量的影响规律,并比较了试件表面及芯部吸入面溶液吸入特性的差异;分析了冻融循环1 000次对溶液吸入特性的影响,给出了不同吸入面的毛细吸液系数.研究表明:活性粉末混凝土毛细吸液量随着NaCl质量分数的增大而减小;15~180 min和180~540 min两阶段溶液吸入量均与t1/2呈线性关系;试件表面毛细吸液系数远小于芯部;冻融循环1 000次后溶液吸入量显著降低,仅为冻融循环前的0.33倍;冻融循环1 000次后距离试件表面越远的吸入面毛细吸液系数越大.     

建筑用热轧奥氏体304不锈钢管力学性能

为了解热轧无缝不锈钢管材料性能,分别对取材自奥氏体304 Φ216×16 mm热轧不锈钢管的光滑和缺口圆棒试件进行单调和循环加载两类试验,获取了应力-应变关系及基本材料参数,得到滞回和骨架曲线,标定钢材循环强化参数,并观察了断面微观破坏特征．研究表明:国产热轧不锈钢管加工工艺对中厚管材性影响不大;奥氏体304不锈钢在循环荷载作用下具有良好强化效应和耗能性能;宜采用随动-等向混合强化材料模型描述其行为,所标定循环强化参数可用于复杂应力状态下的数值模拟;不锈钢材微观破坏特征异于普通低合金或低碳钢．     

组合塔式结构及其效能研究

提出组合塔式结构的设计理念与基本形式,并对其受力机理进行了深入研究。组合塔式结构的基本特征是在塔楼之间设置多道连接桁架,形成由多个单塔与连接桁架构成的巨型结构,使结构的整体抗倾覆性能显著提高。深入研究了连接桁架刚度对结构效能的影响,引入了组合塔式结构的整体弯矩系数。研究结果表明：与传统的结构形式相比,组合塔式结构的抗侧力效能显著提高,可以大大突破单塔的高宽比限值,在现有建筑材料与施工技术条件下,能够建造更高的超高层建筑,并成为未来超高层建筑发展的主要方向之一。     

高校工会主席胜任力模型研究

胜任力是工作表现背后所蕴含的个人能力和行为总和,它能够有效反映出个体对于某一岗位的适应性及耦合度.运用行为事件访谈技术、质性研究及问卷调查方法构建了高校工会主席胜任力模型,研究结果显示个人特质、领导能力、协调变通能力、战略管理能力、服务关怀意识、学习创新能力是高校工会主席的核心胜任力.     

潜水搅拌器安装角度对搅拌效果的影响

研究潜水搅拌器水平安装角度对搅拌池内流场的影响,建立不同的水平安装角度,通过Fluent对潜水搅拌机的搅拌槽内流场进行三维数值模拟,得出不同方案的速度分布情况.利用UDF模块,分别计算流场中流速达到搅拌效果的有效搅拌流体体积及其占整个流场体积的百分比,通过比较,选出最优的潜水搅拌器安装方案,提出了评价潜水搅拌器效能及其安装布置优劣的新方法——有效搅拌域法,利用此方法,使潜水搅拌器的搅拌效果分析更加准确.     

大数据时代科技期刊出版面临的发展机遇与保密挑战

本文将在介绍大数据基本概念、特点及其价值的基础上,探讨大数据分析与传统数据分析的异同,研究大数据分析对科技期刊选题优化的支撑意义以及给科技期刊保密工作带来的挑战,提出加强科技期刊保密工作的建议。