基于邻层数据匹配的工业 CT 图像生成 G 代码方法

针对目前工业CT图像转换为3D打印G代码方法效率低的问题,提出一种基于邻层数据匹配的工业CT图像直接转换成G代码的方法。首先采用Canny算子提取工业CT图像的轮廓,然后处理轮廓分叉问题,实现邻层间几何信息数据匹配,其次进行邻层间轮廓插值以满足3D打印层间厚度要求,从而避免"阶梯效应",最后通过填充编码得到用于3D打印的G代码。使用本文提出的方法,轮毂CT图像转换为G代码的时间为10.5 s,耗时远小于其他间接转换方法;3D打印出的轮毂无"阶梯效应",平均尺寸误差率为0.25%。实验结果表明,该方法不涉及中间格式,转换效率高,转换误差与传统方法相当,适用于具有复杂内腔结构的零件。     

复合顶板动压巷道围岩应力演化和支护技术研究

三交河矿10_^#下煤层顶板为典型复合岩层,从已掘巷道来看,10_^#下煤层巷道顶板成型不佳,容易风化破碎,受采动影响下易出现顶板离层破碎下沉等破坏现象。10-2032巷为复合顶板条件采掘对穿巷道,支护难度较大,在分析地质条件的基础上,通过数值模拟,对10-2032巷与10-201回采面对穿前后的应力状态进行了分析。结合应力演化情况和锚杆支护原理,根据工程类比和数值模拟结果,提出10-2032巷锚杆锚索支护设计。顶板采用长短锚索组合支护,两帮采用单体锚杆搭配W钢护板支护,井下实践证明,与相邻回采面对穿后,2032巷仍能保持较好的支护效果。     

基于微博用户兴趣话题的相似用户挖掘

相似用户挖掘是提高社交网络服务质量的重要途径，在面向大数据的社交网络时代，准确的相似用户挖掘对于用户和互联网企业等都有重要的意义，而根据用户自己的兴趣话题挖掘的相似用户更符合相似用户的要求。提出了一种基于用户兴趣话题进行相似用户挖掘的方法。该方法首先使用TextRank话题提取方法对用户进行兴趣话题提取，再对用户发表内容进行训练，计算出所有词之间的相似度。提出CP（Corresponding Position similarity）、CPW（Corresponding Position Weighted similarity）、AP（All Position similarity）、APW（All Position Weighted similarity）四种用户兴趣话题词相似度计算方法，通过用户和相似用户间关注、粉丝重合率验证相似用户挖掘效果，APW similarity的相似用户的关注/粉丝重合百分比为1.687%，优于提出的其他三种算法，分别提高了26.3%、2.8%、12.4%，并且比传统的文本相似度方法Jaccard相似度、编辑距离算法、余弦相似度分别提高了20.4%、21.2%、45.0%。因此APW方法可以更加有效地挖掘出用户的相似用户。     

Collective institutional work: the case of Airbnb in Amsterdam,London and New York

ABSTRACT

Given that online platforms disrupt established industries and challenge existing institutions, they can only be successful if their innovation becomes both legal and legitimate. This requires ‘institutional work’ that changes perceptions and regulations within society. Rather than only focussing on the online platform as the sole agent engaging in institutional work, our study analyses institutional work as a collective process. We investigate the case of home-sharing platform Airbnb and the process of institutional change its introduction prompted regarding short-term rental in Amsterdam, London and New York. We find, contrary to the popular view of online platforms as disruptive entrepreneurs, that the platform mainly focusses on creating new institutions rather than disrupting existing ones, and that users and non-users undertake most of the institutional work activities. We also show that different types of actors carry out different types of institutional work suggesting that the process of institutional work is highly distributed.     

相邻雷达回波强度差异分析

文章选用2017-12-13的青浦站和南通站体扫数据和单站格点CAPPI数据,利用时空一致性匹配法和单站格点数据等距离线法对两站雷达回波强度差异情况进行了研究,并分析了两种算法可能存在的误差,结果表明:单站格点数据等距离线法要优于时空一致性匹配法,更适用于单部雷达体扫数据的相邻雷达回波差异对比;在雷达基数据正确的情况下,时空一致性匹配法误差主要来源于做不到真正的时空匹配一致,格点数据等距离线法误差主要来源于生成格点数据时插值算法不完善。     

Users in the design of Hydrogen Energy Systems: A systematic review

The energy transition is a major societal issue to which hydrogen energy can make an important contribution. If the technical aspects of hydrogen energy seem paramount, it is also important to focus on the end users of these future systems. Indeed, users play an important role in the success of energy systems: they may not accept it, they may not use it as intended. But not only, users can also be a source of innovation. Thus, it is possible to mobilize different approaches, which if they are all legitimate, do not have the same efficiency. In this systematic review of the literature, which combines lexical analysis and data analysis of 152 publications, we identify the approaches implemented to take into account users in Hydrogen Energy Systems. Our results indicate that final users are mostly perceived as a barrier to the deployment of Hydrogen Energy Systems, or as a parameter to be assessed rather than as a resource for the design. Researches have mainly the aim of improving technology adoption. Since Hydrogen Energy Systems are emerging, we recommend focusing studies on upstream user research aimed at stimulating and enhancing technologies and systems design. We also recommend increasing the share of study which focus on the case of hydrogen energy stationary applications and buildings.     

售电市场环境下售电公司与电力用户双层博弈模型研究

售电市场放开是我国售电侧改革的发展方向,竞争性售电市场中用户选择权放开,用户选择结果影响售电公司的售电策略,售电公司售电策略又会直接影响用户选择。构建售电公司与电力用户间双层博弈模型,下层模型为用户层演化博弈,上层模型为售电公司间非合作博弈。首先分析影响用户选择售电公司的因素,建立用户效用模型,采用演化博弈理论构建不同类型用户群体选择售电公司的多群体动态演化模型。在构建用户选择模型的基础上,分析售电公司的购售电策略,计及售电公司面临的风险因素,建立售电公司和电力用户的双层博弈模型并给出了博弈均衡的求解算法。算例分析结果表明,所构建的模型和算法具有可行性和有效性。     

Fake news and COVID-19: modelling the predictors of fake news sharing among social media users

Fake news dissemination on COVID-19 has increased in recent months, and the factors that lead to the sharing of this misinformation is less well studied. Therefore, this paper describes the result of a Nigerian sample (n = 385) regarding the proliferation of fake news on COVID-19. The fake news phenomenon was studied using the Uses and Gratification framework, which was extended by an “altruism” motivation. The data were analysed with Partial Least Squares (PLS) to determine the effects of six variables on the outcome of fake news sharing. Our results showed that altruism was the most significant factor that predicted fake news sharing of COVID-19. We also found that social media users’ motivations for information sharing, socialisation, information seeking and pass time predicted the sharing of false information about COVID-19. In contrast, no significant association was found for entertainment motivation. We concluded with some theoretical and practical implications.     

基于心智模型的新闻资讯APP适老化设计探究

目的 针对乐龄用户常用新闻资讯APP的适老化问题，通过构建和运用乐龄用户心智模型，探讨符合老年用户使用需求的新闻资讯APP设计。方法 通过对现有新闻资讯APP适老化设计存在的问题进行分析，以使用APP获取新闻资讯为行动目标，将“执行”“评估”行为作为获取乐龄用户心智信息的维度，对维度属性进行发散并拟定用户访谈提纲。应用亲和图法对用户的受访回答进行聚类分析，构建乐龄用户使用APP获取新闻资讯的心智模型。据此提出适老性新闻资讯APP设计策略，并进行“易新闻”APP的设计。结果 选择现有主流新闻资讯APP与“易新闻”APP进行可用性测试对比，USE量表测试结果“易新闻”设计在易用性、易学性、满意度三个方面的指标高于现有APP;任务测试显示“易新闻”设计较现有APP完成时间更短，完成率更高。结论 从乐龄用户行为的“执行”与“评估”维度获取心智信息，运用亲和图法构建乐龄用户心智模型，能够帮助设计者发掘用户需求并指导设计实践，实现提高APP适老性的目的。     

晋陕蒙接壤区露天矿不同质地土壤水分运动特征与模拟

分析了晋陕蒙接壤区不同质地土壤水分运动规律，为构造一种理想的层状土体提供参考依据。设置沙土、砒砂岩、黄绵土和红黏土4种均质土柱，利用室内土柱自动观测系统测定4种矿区土壤入渗及蒸发过程，结合HYDRUS-1D模型反解土壤水力参数，并利用反解的参数模拟土壤的入渗与蒸发过程。通过湿润峰运移、入渗速率、累积入渗量评价土壤入渗性能，对比蒸发强度和移动能力评价土壤蒸发性能。研究结果表明，不同质地土壤入渗性能与蒸发性能差异较大，入渗性能从大到小排序为：沙土、砒砂岩、黄绵土、红黏土，蒸发性能从大到小排序为：黄绵土、红黏土、沙土、砒砂岩。4种土壤入渗过程模拟结果的Re（相对误差）绝对值都在11.0%以下，R2在0.90以上，沙土、黄绵土、红黏土蒸发过程模拟结果Re（相对误差）绝对值在6.1%以下，R2在0.94以上，砒砂岩因质地特殊，蒸发过程模拟结果Re（相对误差）绝对值为14.0%，R2仅为0.44，整体评价利用HYDRUS-1D结合入渗、蒸发过程剖面含水量变化反演土壤水力参数具有较高的精度。不同质地土壤水分运动特征的测定与模拟，对指导露天矿区排土场新土体构筑提供了参考。