The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling     

Samuel J. Callaghan  Robert G. Lockie  Warren A. Andrews  Robert F. Chipchase  Sophia Nimphius 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(3):307-321

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.  相似文献   

Using an interactive platform to recognize the intersection of social and spatial inequalities     

Lisa Poling  Travis Weiland 《Teaching Statistics》2020,42(3):108-116

With the creation of interactive tasks that allow students to explore spatial ways of knowing in conjunction with their other ways of knowing the world, we create a space where students can make sense of information as they organize these new ideas into their already existing schema. Through the use of a Common Online Data Analysis Platform (CODAP) and data from Public Use Microdata Areas (PUMA), students can explore the communities in which they live and work, critically examining opportunities and challenges within a defined space.  相似文献   

睡美人文献识别方法研究进展     

宗张建 《图书情报工作》2019,63(16):132-142

[目的/意义]睡美人文献是一类蕴藏着巨大科学价值的文献。对国内外睡美人文献识别方法的相关研究成果进行总结与梳理，形成比较完整的综述内容，为国内该领域研究提供参考与借鉴。[方法/过程]按方法属性将识别方法总结为4类，概括各识别方法的基本思路、识别标准、优点及局限性，并参照睡美人文献识别方法的4条原则进行对比，指出各识别方法的适用范围。[结果/结论]睡美人文献识别方法已由单一逐渐丰富，从主观参数向客观指标演变，从单一引文曲线向多种形式曲线并用发展。未来睡美人文献识别研究可从睡眠深度标准再定义、识别方法再组合上深入。此外，还需重视睡美人文献的定性研究和识别方法的验证性研究，重视睡美人引文价值的测度以及预测性研究。  相似文献   

用户动机视角下的Altmetrics指标研究     

刘晓娟  王晨琳 《图书情报知识》2020,(3):63-70,96

[目的/意义]从用户动机视角对Altmetrics指标的本质和价值进行分析,使Altmetrics的应用更为科学合理。[研究设计/方法]首先对相关文献中的动机进行组织提炼与规范化表述。在此基础上引入用户行为理论解释和分析用户动机体现的指标价值。再选取Twitter提及量指标,使用内容分析法进行案例研究。[结论/发现]提炼出19种用户动机,其中有6种动机会降低指标应用价值。[创新/价值]探索Altmetrics数据的产生机制,在一定程度上回答了Altmetrics指标可用性问题。  相似文献   

The effects of limb dominance and a short term,high intensity exercise protocol on both landings of the vertical drop jump: implications for the vertical drop jump as a screening tool     

Enda F. Whyte  Patrick Kennelly  Oliver Milton  Chris Richter  Siobhán O’Connor  Kieran A. Moran 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(4):541-553

The effectiveness of vertical drop jumps (VDJs) to screen for non-contact ACL injuries is unclear. This may be contributed to by discrete point analysis, which does not evaluate patterns of movement. Also, limited research exists on the second landing of VDJs, potential lower limb performance asymmetries and the effect of fatigue. Statistical parametric mapping investigated the main effects of landing, limb dominance and a high intensity, intermittent exercise protocol (HIIP) on VDJ biomechanics. Twenty-two male athletes (21.9 ± 1.1 years, 180.5 ± 5.5 cm, 79.4 ± 7.8 kg) performed VDJs pre- and post-HIIP. Repeated measures ANOVA identified pattern differences during the eccentric phases of the first and second landings bilaterally. The first landing displayed greater (internal) knee flexor (η² = 0.165), external rotator (η² = 0.113) and valgus (η² = 0.126) moments and greater hip (η² = 0.062) and knee (η² = 0.080) flexion. The dominant limb generated greater knee flexor (η² = 0.062), external rotator (η² = 0.110) and valgus (η² = 0.065) moments. The HIIP only had one effect, increased thoracic flexion relative to the pelvis (η² = 0.088). Finally, the dominant limb demonstrated greater knee extensor moments during the second landing (η² = 0.100). ACL injury risk factors were present in both landings of VDJs with the dominant limb at potentially greater injury risk. Therefore, VDJ screenings should analyse both landings bilaterally.  相似文献   

主客观信息融合的港口综合能源系统评价指标体系     

何大春  谈健  苏宜强  解翔  宋天立  蔡超  陈曦 《上海海事大学学报》2020,41(3):110-116

为建立绿色港口，实现港口的节能环保，对港口综合能源系统(port integrated energy system，PIES)的评价方法进行研究，提出一种主客观信息融合的PIES评价指标体系，将主观评价与数理统计模型进行结合，兼顾评价过程中的主客观因素，并采用基于马氏距离的统计检验方法对评分矩阵进行修正，实现对PIES的全面评价。通过青岛港董家口港区的调研数据，验证该方法的有效性。  相似文献   

The role of pelvis-thorax coupling in controlling within-golf club swing speed     

Peter F. Lamb  Todd C. Pataky 《Journal of sports sciences》2018,36(19):2164-2171

Pelvis-thorax coordination has been recognised to be associated with swing speed. Increasing angular separation between the pelvis and thorax has been thought to initiate the stretch shortening cycle and lead to increased clubhead speed. The purpose of this study was to determine whether pelvis-thorax coupling played a significant role in regulating clubhead speed, in a group of low-handicap golfers (mean handicap = 4.1). Sixteen participants played shots to target distances determined based on their typical 5- and 6-iron shot distances. Half the difference between median 5- and 6-iron distance for each participant was used to create three swing effort conditions: “minus”, “norm”, and “plus”. Ten shots were played under each swing effort condition using both the 5-iron and 6-iron, resulting in six shot categories and 60 shots per participant. No significant differences were found for X-factor for club or swing effort. X-factor stretch showed significant differences for club and swing effort. Continuous relative phase (CRP) results mainly showed evidence of the stretch shortening cycle in the downswing and that it was more pronounced late in the downswing as swing effort increased. Substantial inter-individual CRP variability demonstrated the need for individual analyses when investigating coordination in the golf swing.  相似文献   

初生期创业企业商业模式预评价指标体系构建研究   总被引：1，自引：1，他引：0       下载免费PDF全文

王雪冬  田明昊  匡海波 《科研管理》2018,39(9):159-168

鉴于当前初创企业商业模式预评价的理论和实践难题，本研究综合运用R-聚类和变异系数分析等多种定性和定量研究方法，建立了定量的、层次化的初创企业商业模式预评价指标体系。该指标体系共包括目标层、准则层和指标层等三个层次，以商业模式竞争力为目标层，以创新度、成长度、效率度、稳定度、盈利度、区隔度、包容度等为准则层，并包括新颖性、差异化程度等29个指标层衡量指标。本研究丰富了商业模式预评价研究，在当前多样化、分散的商业模式预评价研究中建立起了初步的沟通桥梁，为初创企业在诸多商业模式潜在预案中做出抉择提供了可操作的评价指标体系依据，有助于商业模式理论研究和实践探索的深入。  相似文献   

论数字图书馆评估   总被引：3，自引：0，他引：3  

杨慕莲 《情报科学》2005,23(11):1663-1667

评估是图书馆发展中的必不可少的一部分，数字图书馆是传统图书馆发展的高级阶段，其评估的内涵与外延相应具有一些新的特征，甚至在某些地方要重新诠释。本文试就数字图书馆评估的相关理念提出了一点拙见以供广大同仁探讨。  相似文献   

美国校企合作案例及评价标准研究   总被引：4，自引：0，他引：4  

于惊涛  武春友 《研究与发展管理》2004,16(5):89-96

校企合作在提高企业技术竞争力,拓展企业技术资源方面起着重要作用。校企合作还加快了新技术市场化的进程,20世纪90年代美国的校企合作取得了巨大的成功。通过四个典型案例重点介绍了当代美国大学与企业合作研究的情况,并对校企合作中的关键问题进行了探讨。  相似文献