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51.
Martin Weiss Alexandra Newman Ceri Whitmore Stephan Weiss 《European Journal of Sport Science》2016,16(4):393-401
Sprint and distance running have experienced remarkable performance improvements over the past century. Attempts to forecast running performances share an almost similarly long history but have relied so far on relatively short data series. Here, we compile a comprehensive set of season-best performances for eight Olympically contested running events. With this data set, we conduct (1) an exponential time series analysis and (2) a power-law experience curve analysis to quantify the rate of past performance improvements and to forecast future performances until the year 2100. We find that the sprint and distance running performances of women and men improve exponentially with time and converge at yearly rates of 4% ± 3% and 2% ± 2%, respectively, towards their asymptotic limits. Running performances can also be modelled with the experience curve approach, yielding learning rates of 3% ± 1% and 6% ± 2% for the women's and men's events, respectively. Long-term trends suggest that: (1) women will continue to run 10–20% slower than men, (2) 9.50 s over 100 m dash may only be broken at the end of this century and (3) several middle- and long-distance records may be broken within the next two to three decades. The prospects of witnessing a sub-2 hour marathon before 2100 remain inconclusive. Our results should be interpreted cautiously as forecasting human behaviour is intrinsically uncertain. The future season-best sprint and distance running performances will continue to scatter around the trends identified here and may yield unexpected improvements of standing world records. 相似文献
52.
周绍平 《江苏广播电视大学学报》2005,16(6):58-60
单片机开发应用中经常用到延时控制,延时控制的基本方法有纯软件、纯硬件及软硬件结合方法,它们都有各自的特点及应用范围,以1秒延时为例给出用三种方法实现的过程,并介绍了软硬件结合延时的应用实例。 相似文献
53.
李建栋 《阜阳师范学院学报(社会科学版)》2006,(3):1-3
文章通过对《文馆词林》所存两篇残敕的文本进行分析,并将其与历史资料对照验证,得出此二敕的作者均为唐太宗,此二敕的写作时间分别为贞观二年(528)正月、三月。 相似文献
54.
55.
李萍 《黄河科技大学学报》2003,5(2):124-126
网络时代,高校师生的学习方式和生活方式发生了深刻变化。互联网在促进教育发展和人才培养的同时,对学生的消极影响不容忽视。要多方面加强思想政治工作,如开辟网上“思想政治教育课堂”、设置“网上德育阵地”、建立信息监控等。 相似文献
56.
研究“与时俱进”范畴的创造过程,考察其如何从中华元典中走采,有助于理解马克思主义的理论自身的发展路数。在马克思主义经典著作家中,是江泽民将“与时俱进”语词从中华文化类似词组中提升出来,对其进行元典式的发展,即赋予其原创性、经典性、大众性意义,使其成为马克思主义发展史上的重要范畴。 相似文献
57.
中国古代职业技术教育之方法 总被引:1,自引:0,他引:1
艺徒训练制贯穿中国古代职业教育历史进程,无论是世承制、官工作坊制,还是官工业制、民间师承制,都倡导或坚持了技艺、规范和就业道德融为一体,注重示范与模仿、总结与交流。案例教育方法不仅体现在职医、职官教育之中,也体现在吏员训练和艺徒训练等方面。算学教育渗透于天文历算、冶炼铸造、纺织制器、赋税徭役、商贾买卖等职业技术教育之中,坚持联系生产、生活实际于始终。 相似文献
58.
介绍利用相关技术对运动物体速度进行测量的原理和实验方法,通过相关测速实验装置及其软件操作界面的介绍,进一步阐明“软件即仪器”的思想。 相似文献
59.
Larry E. Suter 《International Journal of Science Education》2016,38(4):663-687
Elementary and secondary students spend more hours outside of class than in formal school and thus have more time for interaction with everyday science. However, evidence from a large international survey, Program of International Student Assessment (PISA) (OECD 2012), found a negative relationship between number of hours attending after-school science and science assessment scores in many countries, raising questions about why. The secondary analysis of the 2006, 2009, and 2012 PISA surveys found that in most Western countries the longer students attended after-school science programs (in a typical week), the lower their PISA standardized science test score, but the higher their positive attitudes toward future science careers, interest in science, and self-confidence in science. Several potential hypotheses for this relationship are examined and rejected. Further analysis of a causal relationship between frequent attendance in after-school programs and student achievement and attitudes should clearly identify the content of the program so that the analysis could distinguish experiences closely related to regular school curricula from the informal science activities that are not. A new analysis also should include carefully designed longitudinal surveys to test the effectiveness of informal experiences on later life choices in career and study. 相似文献
60.
针对线性离散系统,研究了开环动态迭代学习控制律的设计问题.首先给出了闭环系统的收敛充分条件,然后把迭代控制转化为H∞设计问题,最后利用线性矩阵不等式(LMI)方法求解迭代学习控制器.通过仿真实例表明了设计方法的有效性. 相似文献