基于正态云可拓理论的锚泊安全评价     

鲁峰  李伟  宁君  于仁海 《上海海事大学学报》2020,41(4):30-35

为提高锚泊安全评价精度，保障船舶锚泊安全，针对传统锚泊安全评价方法未考虑评价等级界限的不确定性和模糊性等问题，将正态云可拓理论应用于锚泊安全评价中。采用层次分析法和基于可拓学的简单关联函数确定权重的方法分别确定锚泊安全评价指标的主观和客观权重，通过经验因子将主观与客观权重进行结合。构建基于正态云可拓理论的锚泊安全评价模型，计算待评物元与标准可拓物元的关联度，通过信息熵理论确定锚泊安全等级。根据信息熵理论定义可信因子，使得评价结果的可信度易于定量计算。实例计算验证了本模型的有效性和优越性。  相似文献   

熵的微分统计法     

肖红 《六盘水师范高等专科学校学报》2003,15(4):22-24

运用累加局城熵的思路,参考经典统计和量子统计原理,建立一种通俗、直观、朴实的统计法,依据它可顺利地求得体系的熵。  相似文献   

生态经济谈略     

姚云珍  马国军 《扬州教育学院学报》2006,24(4):44-46

指出了传统经济的痼疾,阐述了生态经济产生的历史背景及其重要意义。  相似文献   

基于熵权-TOPSIS模型的大风浪条件下引航员登船水域选址     

周宁  范中洲  赵羿 《上海海事大学学报》2020,41(1):46-50

为保障大风浪条件下引航员登船安全、周边船和被引船的安全以及港口的安全高效运营,选取合理的引航员登船水域至关重要。综合考虑熵权法和TOPSIS法的优点,基于熵权-TOPSIS模型对大风浪条件下引航员登船水域进行优选研究。以大风浪条件下广州港引航员登船水域选址为例,运用该模型对3个备选方案进行评价,求得方案2的相对贴近度最大。该方案所述的引航员登船水域为大风浪条件下最优登船水域,且与实际选址一致。经实例验证,该模型较为可靠,实用性强。  相似文献   

Timescales for exploratory tactical behaviour in football small-sided games     

Angel Ric  Robert Hristovski  Bruno Gonçalves  Lorena Torres  Jaime Sampaio  Carlota Torrents 《Journal of sports sciences》2016,34(18):1723-1730

The aim of this study was to identify the dynamics of tactical behaviour emerging on different timescales in football small-sided games and to quantify short- and long-term exploratory behaviour according to the number of opponents. Two teams of four professional male footballers played small-sided games against two different teams with a variable number of opponents (3, 5 and 7). Data were collected using a combination of systematic observation and a non-differential global positioning system (15 Hz). The temporal diversity and structural flexibility of the players were determined by calculating the dynamic overlap order parameter q, entropy and trapping strength. Analysis of the exploratory dynamics revealed two different timescales, forming a different metastable landscape of action for each constraint. Fast dynamics lasted on average a few seconds and consisted of changes in tactical patterns. The long timescale corresponded to the shared tasks of offence and defence lasting tens of seconds. The players’ tactical diversity decreased with an increasing number of opponents, especially in defence. Manipulating numerical imbalance is likely to promote changes in the diversity, unpredictability and flexibility of tactical solutions. The fact that the temporally nested structure of constraints shaped the emergence of tactical behaviour provides a new rationale for practice task design. The manipulation of numerical imbalance on the timescale of a few tens of seconds, on which the exploratory behaviour of players saturates, may help coaches to optimise the exploratory efficiency of the small-sided games.  相似文献   

广义马氏过程及其熵率     

张景晓  连秀国  李光芹  姜曰华 《临沂师范学院学报》2004,26(3):26-28

讨论了k步广义马氏过程及其时间不变性和平稳性，给出了熵率的两种定义，说明了其等价性，还给出了平稳的广义马氏链熵率的计算公式．  相似文献   

山东省会城市群经济圈科技投入与产出评价体系研究     

岳海鸥张彦奇  吕芳芳王红芬 《中国科技资源导刊 (中国信息导报)》2016,(5):19-26

通过构建科技创新体系评价指标,研究山东省会城市群经济圈科技投入与发展现状。运用熵值法确定指标 权重,对科技创新的核心因素进行深入分析,结合聚类分析法对经济圈内各地市的科技投入与产出情况进行比较评价 和分类研究,并给出提升经济圈科技投入与产出水平的对策建议。  相似文献   

Alterations in autonomic cardiac modulation in response to normobaric hypoxia     

David Giles  John Kelly 《European Journal of Sport Science》2016,16(8):1023-1031

Purpose: The present study aimed to determine if autonomic cardiac modulation was influenced by acute exposure to normobaric hypoxia. Method: Ten healthy male lowland dwellers completed five block-randomised single-blinded, crossed-over acute exposures to a normobaric hypoxic environment, each separated by 24 hours’ recovery (20.3%, 17.4%, 14.5%, 12.0% and 9.8% F_IO₂). Supine recordings were made of arterial oxygen saturation and electrocardiogram (ECG). RR intervals from the ECG trace were analysed for time (SDNN, lnrMSSD), frequency (lnVLF, lnLF, lnHF, lnTP, LFnu, and HFnu), and nonlinear (DFA-α1 and SampEn) heart rate variability components. Results: A significant reduction in arterial SaO₂ occurred with reduced F_IO₂, along with a rise in heart rate (Cohen’s d?=?1.16, 95% Confidence Interval [2.64–6.46]), significant at 9.8% F_IO₂. A decrease in autonomic cardiac modulation was also found as shown by a statistically significant (at 9.8% F_IO₂) decrease in lnTP (d?=?1.84 [1.74–1.94]), and SampEn (d?=?0.98 [0.83–1.12]) and an increase in DFA-α₁ (d?=?0.72 [0.60–0.84]) from normoxia at 9.8% F_IO₂. Conclusion: The decrease in variability indicated a reduction in autonomic cardiac modulation. There appears to be a threshold ～9.8% F_IO₂ (～6000?m equiv.), below which significant alterations in autonomic control occur.  相似文献   

关于熵的几点注记     

潘留仙  左伟明 《湖南城市学院学报》2003,24(6):70-74

对熵概念的泛化进行了诠释.  相似文献   

随机变量的熵与标准熵     

王雪琴 《三门峡职业技术学院学报》2003,2(4):33-34

本文研究随机变量的熵与标准熵、标准差之间的关系,得出的结论是:对于离散型的随机变量熵与标准熵相等,与标准差无关;对于连续型随机变量ξ(ξ是的ξ标准化随机变量),熵H(ξ)等于它的标准熵H(ξ)加标准差的对数σ。从而揭示出两类常见的随机变量之间的本质性差异:离散型随机变量的不确定度与离散度无关,连续型随机变量的不确定度与离散度(标准差)呈对数关系。  相似文献