雷击对碳纤维增强型航空复合材料损伤的影响

依据有限元仿真软件ABAQUS,建立碳纤维增强型复合材料(CFRP)层合板雷击损伤热-电耦合有限元仿真模型。利用叠加温度场的方法来近似表示内部受损状态,通过对比实验验证热-电耦合仿真方法的正确性与有效性。利用回归统计分析技术,定量分析雷电参数与CFRP雷击损伤的相关性,并绘制相关曲线。结果表明:雷电流比能是决定CFRP雷击损伤的关键因素,纤维破坏面积、分层面积与比能具有线性相关性,树脂破坏面积、分层厚度与比能具有对数相关性。     

标准有关信息对公众产品质量认知影响研究

标准支撑经济社会健康发展的作用显著提高了公众对标准问题的关注和标准与产品质量相关性的探索意愿.但受标准技术性和专业性的影响,其对一般公众而言知识的可及性相对较差,因此可能导致标准有关信息的引入对公众的产品认知与其他外部信息的影响有不同的发展规律.本文以标准作为兼具技术性和公众相关性话题的代表,通过实验分析的方法,观察不同信息叠加对公众的产品态度的影响,讨论了标准对产品质量认知的影响方式.     

关于推广现场混装炸药车技术的一些思考

我国是工业炸药的生产和使用大国,连续多年的产量都超过了400万t,同时工业炸药作为典型的危险物品,与公共安全息息相关,是社会治安管理的重点监管对象。工业炸药现场混装车技术彻底改变了传统商品炸药的生产、供营和使用模式,本质安全性高是其最突出的特点。大力推广应用现场混装车技术无论是对于提高工业炸药的安全生产管理水平,还是对于提升社会治安管理水平,都具有重要意义,因此受到国家法规政策的鼓励。分析了工业炸药现场混装技术的优势,尤其是对于公共安全的有利作用,研究了现行管理模式存在的弊端,提出为促进工业炸药现场混装技术在我国顺利推广,贯彻创新驱动发展战略,通过体制机制创新,建立由公安机关对工业炸药现场混装技术进行统一管理的更有利的监管模式。鼓励有条件的爆破公司购买和使用现场混装车,大幅度减少工业炸药固定生产点、库房和成品炸药运输等危险源。     

不同炮孔堵塞材料对矿山露天爆破效果的影响

通过矿山目前采用的单一材料堵塞的冲孔分析,利用控制变量法和对比分析法,定性地研究炮孔中应力和时间的变化规律,结合现场爆破试验,将炮孔堵塞分6种情况进行试验研究,最终得出:混合材料的炮孔堵塞相比单一材料的炮孔堵塞,具有抗剪强度高、炸药能量在炮孔中作用时间长和炸药做功能力增大等特点。现场混合材料堵塞能有效地降低冲孔现象的发生,提高炸药利用率和减少炮孔上部大块的产生。     

The use of social media in impact assessment: experiences among national infrastructure developers in Denmark

Social media plays an increasingly prominent role in the interaction between impact assessments and society. Impact assessment is thus becoming part of social networks that are claimed to be able to improve interaction between actors in impact assessment processes. By investigating the use of social media in impact assessment and planning processes of national linear infrastructure development, we explore how social media impinge on participatory practices and how the potential of social media is realized in the current use related to public participation processes. The study focuses on experiences among national developers working in road, rail, electricity, gas, and metro infrastructures in Denmark. The article shows that the current use of social media in public participatory practices is limited to branding and on-way communication and that the increasing use of social media in linear infrastructure planning gives rise to a variety of concerns among developers that are related to especially organizational cultures, perception of the target groups, and prioritization of resources.     

一种基于分层的人类动作识别和定位算法研究

人类动作识别在视频自动分析、视频检索等领域获得广泛应用,是目前的研究热点。然而现有的动作识别方法重点关注视频的非静态部分而忽略大部分静态部分,从而影响了动作识别和定位的效果。本文提出一种新的分层空间-时间分段表示法,以分层方式实现部位和整个身体的多分辨率表示,可用于运动识别和定位。该算法分为3个步骤。第一步,首先对每个视频帧进行分层分段,以得到一组分段树,每颗树是身体分段树的候选。第二步,利用视频的轮廓、接合对象结构、全局前景色等信息对候选分段树进行修剪。第三步,在时域上对剩余分段层的每个分段进行前向和后向跟踪。我们以难度较大的UCF-Sports和HighFive数据集为实验对象,对本文方法进行性能评估,实验结果表明,本文方法的性能要优于当前最新运动检测算法性能,运动定位性能与当前最新算法相当。     

Feature Fusion-Based Deep Learning Network to Recognize Table Tennis Actions

A system for classifying four basic table tennis strokes using wearable devices and deep learning networks is proposed in this study. The wearable device consisted of a six-axis sensor, Raspberry Pi 3, and a power bank. Multiple kernel sizes were used in convolutional neural network (CNN) to evaluate their performance for extracting features. Moreover, a multiscale CNN with two kernel sizes was used to perform feature fusion at different scales in a concatenated manner. The CNN achieved recognition of the four table tennis strokes. Experimental data were obtained from 20 research participants who wore sensors on the back of their hands while performing the four table tennis strokes in a laboratory environment. The data were collected to verify the performance of the proposed models for wearable devices. Finally, the sensor and multi-scale CNN designed in this study achieved accuracy and F1 scores of 99.58% and 99.16%, respectively, for the four strokes. The accuracy for five-fold cross validation was 99.87%. This result also shows that the multi-scale convolutional neural network has better robustness after five-fold cross validation.     

Reasoning about action and change

Reasoning about change is a central issue in research on human and robot planning. We study an approach to reasoning about action and change in a dynamic logic setting and provide a solution to problems which are related to the Frame problem. Unlike most work on the frame problem the logic described in this paper is monotonic. It (implicitly) allows for the occurrence of actions of multiple agents by introducing non-stationary notions of waiting and test. The need to state a large number of frame axioms is alleviated by introducing a concept of chronological preservation to dynamic logic. As a side effect, this concept permits the encoding of temporal properties in a natural way. We compare the relative merits of our approach and non-monotonic approaches as regards different aspects of the frame problem. Technically, we show that the resulting extended systems of propositional dynamic logic preserve (weak) completeness, finite model property and decidability.     

一种基于椭圆曲线的序列号软件保护方案

这里提出了一种基于椭圆曲线公钥密码算法的序列号生成方案,结合签名技术,可以防止敌手代码被篡改或者跳过某些重要代码,因此该方案构成一种安全有效的软件保护方案,最后分析了该方案的安全性,并进行了方案的有效性实验.     

基于粗糙集理论在公安工作中的研究

文章将基于粗糙集理论的数据挖掘算法引入公安情报工作,论述了基于粗糙集的关联规则挖掘在刑事案件中的应用实例,证明该算法在公安情报分析工作中的可行性,为公安情报工作提供新的解决方法,对于提高情报分析预测的效率、准确性,以及警力分配具有重要辅助作用。