基于ICWGT和灰色关联分析法的起重机安全评价     

肖汉斌  熊楚宸  祝锋  刘敏 《上海海事大学学报》2020,41(2):117-122

针对目前起重机安全评价过于依赖主观权重且忽视起重机安全状态变化趋势的问题，建立基于改进博弈论组合赋权法（improved combination weighting method of game theory，ICWGT）和灰色关联分析法的起重机安全评价体系。在该评价体系中，收集样本数据以确定评价值，构建评价等级空间来计算起重机行为特征序列与标准行为特征序列的关联系数。运用ICWGT在层次分析法和信息熵 未确知测度理论确定的主、客观权重中寻找平衡。充分考虑专家经验和样本数据，确定优化权重以改善关联系数的分配问题，从而获取起重机灰色关联度评价值和安全等级，旨在对起重机安全状态变化趋势进行更加准确的定量描述和定性分析。实例分析验证了该评价体系的有效性。  相似文献   

图书情报学领域学科交叉及其国家差异的动态分析     

王思茗  滕广青 《图书情报知识》2020,(3):109-118,F0003

[目的/意义]领域知识的跨学科交叉研究能够打破学科间的壁垒,有助于发现重大科学问题的解决方案。[研究设计/方法]基于图书情报学领域文献题录信息构建轻量级领域知识图谱,从中提取学科信息、国家信息、时间信息及其关联,采用时间与空间相结合的多维度分析方法,对学科交叉的演化进程以及国家差异进行跟踪与分析。[结论/发现]图书情报学领域内学科交叉现象日渐显著,各国家的学科交叉程度与倾向存在差异,一些目前尚不突出的交叉学科方向值得关注。[创新/价值]采用多维度视角分析学科交叉现象,相关结论可以为国家科技战略制定及学科发展规划提供有益参考。  相似文献   

Digital Module 16: Longitudinal Data Analysis     

Jeffrey R. Harring  Tessa L. Johnson 《Educational Measurement》2020,39(3):137-138

In this digital ITEMS module, Dr. Jeffrey Harring and Ms. Tessa Johnson introduce the linear mixed effects (LME) model as a flexible general framework for simultaneously modeling continuous repeated measures data with a scientifically defensible function that adequately summarizes both individual change as well as the average response. The module begins with a nontechnical overview of longitudinal data analyses drawing distinctions with cross-sectional analyses in terms of research questions to be addressed. Nuances of longitudinal designs, timing of measurements, and the real possibility of missing data are then discussed. The three interconnected components of the LME model—(1) a model for individual and mean response profiles, (2) a model to characterize the covariation among the time-specific residuals, and (3) a set of models that summarize the extent that individual coefficients vary—are discussed in the context of the set of activities comprising an analysis. Finally, they demonstrate how to estimate the linear mixed effects model within an open-source environment (R). The digital module contains sample R code, diagnostic quiz questions, hands-on activities in R, curated resources, and a glossary.  相似文献   

Contextual factors on physical demands in professional women’s soccer: Female Athletes in Motion study     

Jason D. Vescovi  Olesya Falenchuk 《European Journal of Sport Science》2019,19(2):141-146

The aim of this study was to examine the impact of contextual factors on relative locomotor and metabolic power distances during professional female soccer matches. Twenty-eight players (forwards, n?=?4; midfielders, n?=?12; defenders, n?=?12) that competed in a 90-min home and away match (regular season only). The generalised estimating equations (GEE) was used to evaluate relative locomotor and metabolic power distances for three contextual factors: location (home vs. away), type of turf (natural vs. artificial), and match outcome (win, loss and draw). No differences were observed for home vs. away matches. Moderate-intensity running (20.0?±?1.0?m?min^?1 and 16.4?±?0.9?m?min^?1), high-intensity running (8.6?±?0.4?m?min^?1 and 7.3?±?0.4?m?min^?1) and high-metabolic power (16.3?±?0.5?m?min^?1 and 14.4?±?0.5?m?min^?1) distances were elevated on artificial turf compared to natural grass, respectively. Relative sprint distance was greater during losses compared with draws (4.3?±?0.4?m?min^?1 and 3.4?±?0.3?m?min^?1). Overall physical demands of professional women’s soccer were not impacted by match location. However, the elevation of moderate and high-intensity demands while playing on artificial turf may have implications on match preparations as well as recovery strategies.  相似文献   

Olfaction and emotion: The quest for olfactory restoration in two speech communities     

Sally O. Hastings  Trudy Milburn 《Journal of International and Intercultural Communication》2019,12(2):190-207

ABSTRACT

Olfaction has been described as one of the least studied of the senses. This has certainly proven true in Communication. This project applies Ethnography of Communication and Cultural Discourse Analysis to examine the role that olfaction plays in the cultural meaning systems of two speech communities: residents surrounding the Gowanus Canal and bereaved parents. The cultural hub used to explore the cultural significance of olfaction in both speech communities is feeling. The analyses illustrate how emotions are tied to associated sensations and further become activated through radiants of dwelling, relating and acting. The analysis also shows how olfaction may serve to unify and separate members of a community. The significance of this research encourages stretching the boundaries of communication studies by examining the less studied physical senses and the boundaries of Cultural Discourse Analysis by providing distinctions that others can incorporate when examining feelings.  相似文献   

多旋翼无人机微多普勒特性分析与特征提取     

马娇  董勇伟  李原  李凌霄  杨杰芳 《中国科学院大学学报》2019,36(2):235-243

针对多旋翼无人机目标的识别问题，提出一种基于伽柏（Gabor）变换的瞬时频率估计与快速傅里叶变换（FFT）相结合的微多普勒特征提取算法。首先建立多旋翼无人机旋翼回波模型，并通过仿真分析叶片数目、旋翼转速和初始相位等参数对微多普勒特征的影响，利用Gabor变换得到时频特征。在此基础上通过瞬时频率极大值法提取微多普勒频率，并对瞬时频率采用FFT提取旋翼数和转动频率，从而获得叶片长度估计值。实测数据验证了该算法较为准确地提取无人机的微多普勒参数。  相似文献   

Martin to Brown     

Danielle K. Kilgo  Rachel R. Mourao  George Sylvie 《Journalism Practice》2019,13(4):413-430

The rise of the modern Black Lives Matter movement can be traced back to two key events, the 2012 death of Trayvon Martin and the 2014 death of Michael Brown. Research routinely showed that mainstream media’s narrative choices marginalize and delegitimize protesters and their causes, a pattern known as the protest paradigm. This study provides a longitudinal examination of how the same mainstream media system varied in their coverage of similar events and the degree to which journalists challenged the predicted paradigms conceptualized in other academic work. A content analysis of national newspaper coverage revealed that news before the judicial rulings focused on protesters’ tactics (violence versus peaceful) and changed to the realm of ideas (grievances and demands) after the assailants were considered not guilty of wrongdoing. No progression was found in legitimizing coverage of protests between the two cases.  相似文献   

Digital Module 07: Subscores: Evaluation and Reporting https://ncme.elevate.commpartners.com     

Sandip Sinharay 《Educational Measurement》2019,38(3):114-115

  相似文献   

The influence of water depth on kinematic and spatiotemporal gait parameters during aquatic treadmill walking     

Taeyou Jung  Yumi Kim  Hyosok Lim  Konstantinos Vrongistinos 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):297-307

The purpose of this study was to investigate kinematic and spatiotemporal variables of aquatic treadmill walking at three different water depths. A total of 15 healthy individuals completed three two-minute walking trials at three different water depths. The aquatic treadmill walking was conducted at waist-depth, chest-depth and neck-depth, while a customised 3-D underwater motion analysis system captured their walking. Each participant’s self-selected walking speed at the waist level was used as a reference speed, which was applied to the remaining two test conditions. A repeated measures ANOVA showed statistically significant differences among the three walking conditions in stride length, cadence, peak hip extension, hip range of motion (ROM), peak ankle plantar flexion and ankle ROM (All p values < 0.05). The participants walked with increased stride length and decreased cadence during neck level as compared to waist and chest level. They also showed increased ankle ROM and decreased hip ROM as the water depth rose from waist and chest to the neck level. However, our study found no significant difference between waist and chest level water in all variables. Hydrodynamics, such as buoyancy and drag force, in response to changes in water depths, can affect gait patterns during aquatic treadmill walking.  相似文献   

The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献