前交叉韧带损伤发生率逐年增加,给个人的生活和职业发展带来消极的影响。目的分析国内外前交叉韧带损伤相关研究的热点和趋势。方法文献检索自Web of Science(WOS)核心数据库和中国知网(CNKI)数据库,检索时间设为2011-2021年,对前交叉...前交叉韧带损伤发生率逐年增加,给个人的生活和职业发展带来消极的影响。目的分析国内外前交叉韧带损伤相关研究的热点和趋势。方法文献检索自Web of Science(WOS)核心数据库和中国知网(CNKI)数据库,检索时间设为2011-2021年,对前交叉韧带损伤为主题的相关文献进行CiteSpace知识图谱的绘制及可视化分析。结果与结论1)共纳入8114篇文献,近11年该领域国内外的发文量都呈现增长趋势。2)发文量排名前5的国家依次是美国、中国、日本、澳大利亚、德国,发文量前5的研究机构都属于美国,其中俄亥俄州立大学发文量居于榜首,发文最多的作者是来自该大学的TIMOTHY E HEWETT团队,其主要的研究方向是神经肌肉训练促进前叉韧带重建后的恢复,在该领域具有较高的影响力。国内发文量排名首位的机构是北京大学第三医院运动医学科,该院的敖英芳团队在该领域深耕多年,其主要研究方向为前交叉韧带重建后膝关节的生物力学和步态分析。3)关键词共现分析和聚类表明,前交叉韧带重建和康复是目前该领域研究的热点内容,关键词突现提示前交叉韧带重建后联合治疗促进重返运动可能是未来的研究趋势。展开更多
Forecasting returns for the Artificial Intelligence and Robotics Index is of great significance for financial market stability,and the development of the artificial intelligence industry.To provide investors with a mo...Forecasting returns for the Artificial Intelligence and Robotics Index is of great significance for financial market stability,and the development of the artificial intelligence industry.To provide investors with a more reliable reference in terms of artificial intelligence index investment,this paper selects the NASDAQ CTA Artificial Intelligence and Robotics(AIRO)Index as the research target,and proposes innovative hybrid methods to forecast returns by considering its multiple structural characteristics.Specifically,this paper uses the ensemble empirical mode decomposition(EEMD)method and the modified iterative cumulative sum of squares(ICSS)algorithm to decompose the index returns and identify the structural breakpoints.Furthermore,it combines the least-square support vector machine approach with the particle swarm optimization method(PSO-LSSVM)and the generalized autoregressive conditional heteroskedasticity(GARCH)type models to construct innovative hybrid forecasting methods.On the one hand,the empirical results indicate that the AIRO index returns have complex structural characteristics,and present time-varying and nonlinear characteristics with high complexity and mutability;on the other hand,the newly proposed hybrid forecasting method(i.e.,the EEMD-PSO-LSSVM-ICSS-GARCH models)which considers these complex structural characteristics,can yield the optimal forecasting performance for the AIRO index returns.展开更多
文摘前交叉韧带损伤发生率逐年增加,给个人的生活和职业发展带来消极的影响。目的分析国内外前交叉韧带损伤相关研究的热点和趋势。方法文献检索自Web of Science(WOS)核心数据库和中国知网(CNKI)数据库,检索时间设为2011-2021年,对前交叉韧带损伤为主题的相关文献进行CiteSpace知识图谱的绘制及可视化分析。结果与结论1)共纳入8114篇文献,近11年该领域国内外的发文量都呈现增长趋势。2)发文量排名前5的国家依次是美国、中国、日本、澳大利亚、德国,发文量前5的研究机构都属于美国,其中俄亥俄州立大学发文量居于榜首,发文最多的作者是来自该大学的TIMOTHY E HEWETT团队,其主要的研究方向是神经肌肉训练促进前叉韧带重建后的恢复,在该领域具有较高的影响力。国内发文量排名首位的机构是北京大学第三医院运动医学科,该院的敖英芳团队在该领域深耕多年,其主要研究方向为前交叉韧带重建后膝关节的生物力学和步态分析。3)关键词共现分析和聚类表明,前交叉韧带重建和康复是目前该领域研究的热点内容,关键词突现提示前交叉韧带重建后联合治疗促进重返运动可能是未来的研究趋势。
基金support from National Natural Science Foundation of China(Nos.71774051,72243003)National Social Science Fund of China(No.22AZD128)the seminar participants in Center for Resource and Environmental Management,Hunan University,China.
文摘Forecasting returns for the Artificial Intelligence and Robotics Index is of great significance for financial market stability,and the development of the artificial intelligence industry.To provide investors with a more reliable reference in terms of artificial intelligence index investment,this paper selects the NASDAQ CTA Artificial Intelligence and Robotics(AIRO)Index as the research target,and proposes innovative hybrid methods to forecast returns by considering its multiple structural characteristics.Specifically,this paper uses the ensemble empirical mode decomposition(EEMD)method and the modified iterative cumulative sum of squares(ICSS)algorithm to decompose the index returns and identify the structural breakpoints.Furthermore,it combines the least-square support vector machine approach with the particle swarm optimization method(PSO-LSSVM)and the generalized autoregressive conditional heteroskedasticity(GARCH)type models to construct innovative hybrid forecasting methods.On the one hand,the empirical results indicate that the AIRO index returns have complex structural characteristics,and present time-varying and nonlinear characteristics with high complexity and mutability;on the other hand,the newly proposed hybrid forecasting method(i.e.,the EEMD-PSO-LSSVM-ICSS-GARCH models)which considers these complex structural characteristics,can yield the optimal forecasting performance for the AIRO index returns.
