Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective funct...Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective function,and an air route network node(ARNN)optimization model was developed to circumvent the restrictions imposed by″three areas″,also known as prohibited areas,restricted areas,and dangerous areas(PRDs),by creating agrid environment.And finally the objective function was solved by means of an adaptive ant colony algorithm(AACA).The A593,A470,B221,and G204 air routes in the busy ZSHA flight information region,where the airspace includes areas with different levels of PRDs,were taken as an example.Based on current flight patterns,a layout optimization of the ARNN was computed using this model and algorithm and successfully avoided PRDs.The optimized result reduced the total length of routes by 2.14% and the total cost by 9.875%.展开更多
Isopaxametric quadrilateral elements are widely used in the finite element method. However, they have a disadvantage of accuracy loss when elements are distorted. Spline functions have properties of simpleness and con...Isopaxametric quadrilateral elements are widely used in the finite element method. However, they have a disadvantage of accuracy loss when elements are distorted. Spline functions have properties of simpleness and conformality. A 17onode quadrilateral element has been developed using the bivaxiate quaxtic spline interpolation basis and the triangular area coordinates, which can exactly model the quartic displacement fields. Some appropriate examples are employed to illustrate that the element possesses high precision and is insensitive to mesh distortions.展开更多
针对快速扩展随机树(Rapidly-exploring Random Tree,RRT)算法及其衍生算法路径规划时间长且规划效率低的问题,提出RRT算法与人工势场法结合的PAAPF-RRT机械臂路径规划算法,旨在最短的时间、最小的迭代次数内,在静态环境中找到连接起始...针对快速扩展随机树(Rapidly-exploring Random Tree,RRT)算法及其衍生算法路径规划时间长且规划效率低的问题,提出RRT算法与人工势场法结合的PAAPF-RRT机械臂路径规划算法,旨在最短的时间、最小的迭代次数内,在静态环境中找到连接起始点与终点的最优路径。首先,引入基于地图障碍物分布评估策略和采样区域优化策略,根据地图的障碍物分布、数量调整算法的步长以及偏向概率。然后,伴随随机树的生长,更新随机点的采样区域,保证随机树向目标点生长。其次,将RRT算法与人工势场法结合,当随机树与障碍物发生碰撞时,使用人工势场法引导随机树节点生长避开障碍物,解决了RRT算法随机树生长到障碍物附近且朝目标点生长的方向被障碍物遮挡时随机树无法生长的问题。最后,利用节点修剪策略,把算法生成的初始路径中的冗余节点进行修剪,得到拐点更少、路径更简洁的优化路径。实验结果表明,PAAPF-RRT算法在路径规划时间上对于RRT算法、GB-RRT算法以及RRT*算法分别减少了93.64%、73.58%、93.28%,在迭代次数方面分别下降了91.40%、79.64%、90.58%,在路径长度方面只占其他3种算法的79.34%、86.21%、95.58%。展开更多
目的:探索希氏束-浦肯野传导系统起搏[HPCSP,包括希氏束起搏(HBP)和左束支区域起搏(LBBAP)]联合房室结消融治疗心房颤动(房颤)合并心力衰竭(心衰)的有效性及安全性。方法:在PubMed、Cochrane图书馆、Web of Science、Embase、中国知网...目的:探索希氏束-浦肯野传导系统起搏[HPCSP,包括希氏束起搏(HBP)和左束支区域起搏(LBBAP)]联合房室结消融治疗心房颤动(房颤)合并心力衰竭(心衰)的有效性及安全性。方法:在PubMed、Cochrane图书馆、Web of Science、Embase、中国知网、万方数据库、维普网、中华医学期刊全文数据库检索关于HPCSP联合房室结消融治疗房颤合并心衰患者的研究,检索时间为各数据库建库到2024年7月31日。采用纽卡斯尔-渥太华(NOS)量表对纳入的队列研究进行质量评价,使用Cochrane偏倚风险评价方法评估随机对照研究的质量,并用RevMan 5.4、Stata 15.1软件进行Meta分析。结果:共纳入13项研究,共1071例患者。HPCSP联合房室结消融成功率为93.1%。Meta分析结果显示,在有效性方面,与基线相比,随访时患者的左心室舒张末期内径(LVEDD)[均数差(MD)=-3.11,95%CI:-4.16~-2.06,P<0.00001)]及纽约心脏协会(NYHA)心功能分级(MD=-1.36,95%CI:-1.48~-1.24,P<0.00001)明显改善,左心室射血分数(LVEF)(MD=9.86,95%CI:7.02~12.69,P<0.00001)明显提高,房室结消融后,起搏QRS波时限(QRSd)较基线延长(MD=7.83,95%CI:2.79~12.87,P=0.002);在安全性方面,HPCSP术中及随访时的起搏阈值保持稳定(MD=0.07,95%CI:-0.01~0.15,P=0.11),阻抗较围术期明显下降(MD=-78.84,95%CI:-120.21~-37.47,P=0.0002),并发症发生率为7.9%,心衰再住院率为4.5%,死亡率为5.8%。与双心室起搏相比,HPCSP明显缩短起搏QRSd(MD=-39.08,95%CI:-62.35~-15.80,P=0.001),改善随访LVEF(MD=4.38,95%CI:0.37~8.40,P=0.030),二者LVEDD变化(MD=-9.11,95%CI:-19.93~1.72,P=0.100)差异无统计学意义。随访期间,LBBAP起搏阈值低于HBP(MD=0.61,95%CI:0.23~1.00,P=0.002);LBBAP与HBP终点事件发生率差异无统计学意义(RR=1.47,95%CI:0.83~2.60,P=0.190)。结论:HPCSP联合房室结消融治疗房颤合并心衰有效、安全。HPCSP较双心室起搏可更好的促进心电同步并进一步改善患者心功能,LBBAP起搏参数优于HBP。展开更多
基金supported by the the Youth Science and Technology Innovation Fund (Science)(Nos.NS2014070, NS2014070)
文摘Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe operation.Here,the ARN shortest path was taken as the objective function,and an air route network node(ARNN)optimization model was developed to circumvent the restrictions imposed by″three areas″,also known as prohibited areas,restricted areas,and dangerous areas(PRDs),by creating agrid environment.And finally the objective function was solved by means of an adaptive ant colony algorithm(AACA).The A593,A470,B221,and G204 air routes in the busy ZSHA flight information region,where the airspace includes areas with different levels of PRDs,were taken as an example.Based on current flight patterns,a layout optimization of the ARNN was computed using this model and algorithm and successfully avoided PRDs.The optimized result reduced the total length of routes by 2.14% and the total cost by 9.875%.
基金supported by the Natural Science Foundation of China China (Nos. 60533060, 10672032, and 10726067)the Science Foundation of Dalian University of Technology (No. SFDUT07001)
文摘Isopaxametric quadrilateral elements are widely used in the finite element method. However, they have a disadvantage of accuracy loss when elements are distorted. Spline functions have properties of simpleness and conformality. A 17onode quadrilateral element has been developed using the bivaxiate quaxtic spline interpolation basis and the triangular area coordinates, which can exactly model the quartic displacement fields. Some appropriate examples are employed to illustrate that the element possesses high precision and is insensitive to mesh distortions.
文摘针对快速扩展随机树(Rapidly-exploring Random Tree,RRT)算法及其衍生算法路径规划时间长且规划效率低的问题,提出RRT算法与人工势场法结合的PAAPF-RRT机械臂路径规划算法,旨在最短的时间、最小的迭代次数内,在静态环境中找到连接起始点与终点的最优路径。首先,引入基于地图障碍物分布评估策略和采样区域优化策略,根据地图的障碍物分布、数量调整算法的步长以及偏向概率。然后,伴随随机树的生长,更新随机点的采样区域,保证随机树向目标点生长。其次,将RRT算法与人工势场法结合,当随机树与障碍物发生碰撞时,使用人工势场法引导随机树节点生长避开障碍物,解决了RRT算法随机树生长到障碍物附近且朝目标点生长的方向被障碍物遮挡时随机树无法生长的问题。最后,利用节点修剪策略,把算法生成的初始路径中的冗余节点进行修剪,得到拐点更少、路径更简洁的优化路径。实验结果表明,PAAPF-RRT算法在路径规划时间上对于RRT算法、GB-RRT算法以及RRT*算法分别减少了93.64%、73.58%、93.28%,在迭代次数方面分别下降了91.40%、79.64%、90.58%,在路径长度方面只占其他3种算法的79.34%、86.21%、95.58%。
文摘目的:探索希氏束-浦肯野传导系统起搏[HPCSP,包括希氏束起搏(HBP)和左束支区域起搏(LBBAP)]联合房室结消融治疗心房颤动(房颤)合并心力衰竭(心衰)的有效性及安全性。方法:在PubMed、Cochrane图书馆、Web of Science、Embase、中国知网、万方数据库、维普网、中华医学期刊全文数据库检索关于HPCSP联合房室结消融治疗房颤合并心衰患者的研究,检索时间为各数据库建库到2024年7月31日。采用纽卡斯尔-渥太华(NOS)量表对纳入的队列研究进行质量评价,使用Cochrane偏倚风险评价方法评估随机对照研究的质量,并用RevMan 5.4、Stata 15.1软件进行Meta分析。结果:共纳入13项研究,共1071例患者。HPCSP联合房室结消融成功率为93.1%。Meta分析结果显示,在有效性方面,与基线相比,随访时患者的左心室舒张末期内径(LVEDD)[均数差(MD)=-3.11,95%CI:-4.16~-2.06,P<0.00001)]及纽约心脏协会(NYHA)心功能分级(MD=-1.36,95%CI:-1.48~-1.24,P<0.00001)明显改善,左心室射血分数(LVEF)(MD=9.86,95%CI:7.02~12.69,P<0.00001)明显提高,房室结消融后,起搏QRS波时限(QRSd)较基线延长(MD=7.83,95%CI:2.79~12.87,P=0.002);在安全性方面,HPCSP术中及随访时的起搏阈值保持稳定(MD=0.07,95%CI:-0.01~0.15,P=0.11),阻抗较围术期明显下降(MD=-78.84,95%CI:-120.21~-37.47,P=0.0002),并发症发生率为7.9%,心衰再住院率为4.5%,死亡率为5.8%。与双心室起搏相比,HPCSP明显缩短起搏QRSd(MD=-39.08,95%CI:-62.35~-15.80,P=0.001),改善随访LVEF(MD=4.38,95%CI:0.37~8.40,P=0.030),二者LVEDD变化(MD=-9.11,95%CI:-19.93~1.72,P=0.100)差异无统计学意义。随访期间,LBBAP起搏阈值低于HBP(MD=0.61,95%CI:0.23~1.00,P=0.002);LBBAP与HBP终点事件发生率差异无统计学意义(RR=1.47,95%CI:0.83~2.60,P=0.190)。结论:HPCSP联合房室结消融治疗房颤合并心衰有效、安全。HPCSP较双心室起搏可更好的促进心电同步并进一步改善患者心功能,LBBAP起搏参数优于HBP。
