A linear-time algorithm was recently published (International Conference Proceedings ofPacific Graphics' 94/CADDM' 94, August 26-29 , 1994 , Beijing , China) for computing the convexhull of a simple polygon. I...A linear-time algorithm was recently published (International Conference Proceedings ofPacific Graphics' 94/CADDM' 94, August 26-29 , 1994 , Beijing , China) for computing the convexhull of a simple polygon. In this note we present a counter-example to that algorithm by exhibiting afamily of polygons for which the algorithm discards vertices that are on the convex hull.展开更多
针对启发式算法在无人机不规则复杂地形和多重威胁环境下进行三维航迹规划时,存在路径波动大和优化性能不足的问题,提出结合高程数据的凸包策略以及一种改进的樽海鞘群算法(ISSA)。首先,基于ASTER GDEMV3和Open Street Map数据,构建杭...针对启发式算法在无人机不规则复杂地形和多重威胁环境下进行三维航迹规划时,存在路径波动大和优化性能不足的问题,提出结合高程数据的凸包策略以及一种改进的樽海鞘群算法(ISSA)。首先,基于ASTER GDEMV3和Open Street Map数据,构建杭州某处山区和纽约城市区域的高程模型;其次,结合地形高程信息,采用凸包策略编码并通过B样条曲线构建路径;最后,对樽海鞘群算法在个体位置更新公式上加入自适应Alpha稳定分布策略与非线性扰动策略,以平衡算法的全局开发能力与局部探索能力,并引入贪婪策略和鱼类聚集装置策略,提高算法搜索效率和精度。利用CEC2020测试函数对所提算法进行实验对比,验证了改进算法的性能。实验结果表明,凸包策略能有效提升算法规划能力,且与传统算法相比,改进后的算法能够使无人机的寻优精度更高,代价函数更小。展开更多
为了准确地描述新能源输出功率的波动性和随机性对多能互补微网系统运行的影响,提出了基于数据驱动的多能微网鲁棒优化方法。首先,在传统区间集合的基础上对新能源出力的不确定参数进行多面体集合建模,然后利用具有时空相关性的新能源...为了准确地描述新能源输出功率的波动性和随机性对多能互补微网系统运行的影响,提出了基于数据驱动的多能微网鲁棒优化方法。首先,在传统区间集合的基础上对新能源出力的不确定参数进行多面体集合建模,然后利用具有时空相关性的新能源出力历史数据建立椭球不确定集合,通过连接高维椭球顶点,建立了数据驱动的凸包多面体集合,接着通过放缩凸包集合更好地对不确定参数进行包络。进一步建立了基于数据驱动的多能互补微网鲁棒优化模型,并采用列与约束生成算法(Column and constraint generation,C&CG)对该模型进行求解。最后通过算例进行仿真对比,结果表明,基于数据驱动的多能互补微网鲁棒优化方法可以减少保守性,提高优化结果鲁棒性,证明了所提方法的有效性。展开更多
This paper presents a new and simple scheme to describe the convex hull in R^d,which only uses three kinds of the faces of the convex hull,i.e.,the d-1-faces,d-2-faces and 0-faces.Thus,we develop an efficient new algo...This paper presents a new and simple scheme to describe the convex hull in R^d,which only uses three kinds of the faces of the convex hull,i.e.,the d-1-faces,d-2-faces and 0-faces.Thus,we develop an efficient new algorithm for constructing the convex hull of a finite set of points incrementally. This algorithm employs much less storage and time than that of the previously-existing approaches.The analysis of the running time as well as the storage for the new algorithm is also theoretically made.The algorithm is optimal in the worst case for even d.展开更多
Arc grounding faults occur frequently in the power grid with small resistance grounding neutral points.The existing arc fault identification technology only uses the fault line signal characteristics to set the identi...Arc grounding faults occur frequently in the power grid with small resistance grounding neutral points.The existing arc fault identification technology only uses the fault line signal characteristics to set the identification index,which leads to detection failure when the arc zero-off characteristic is short.To solve this problem,this paper presents an arc fault identification method by utilizing integrated signal characteristics of both the fault line and sound lines.Firstly,the waveform characteristics of the fault line and sound lines under an arc grounding fault are studied.After that,the convex hull,gradient product,and correlation coefficient index are used as the basic characteristic parameters to establish fault identification criteria.Then,the logistic regression algorithm is employed to deal with the reference samples,establish the machine discrimination model,and realize the discrimination of fault types.Finally,simulation test results and experimental results verify the accuracy of the proposed method.The comparison analysis shows that the proposed method has higher recognition accuracy,especially when the arc dissipation power is smaller than 2×103 W,the zero-off period is not obvious.In conclusion,the proposed method expands the arc fault identification theory.展开更多
摘要A linear-time algorithm was recently published (International Conference Proceedings ofPacific Graphics' 94/CADDM' 94, August 26-29 , 1994 , Beijing , China) for computing the convexhull of a simple polygon. In this note we present a counter-example to that algorithm by exhibiting afamily of polygons for which the algorithm discards vertices that are on the convex hull.
摘要针对启发式算法在无人机不规则复杂地形和多重威胁环境下进行三维航迹规划时,存在路径波动大和优化性能不足的问题,提出结合高程数据的凸包策略以及一种改进的樽海鞘群算法(ISSA)。首先,基于ASTER GDEMV3和Open Street Map数据,构建杭州某处山区和纽约城市区域的高程模型;其次,结合地形高程信息,采用凸包策略编码并通过B样条曲线构建路径;最后,对樽海鞘群算法在个体位置更新公式上加入自适应Alpha稳定分布策略与非线性扰动策略,以平衡算法的全局开发能力与局部探索能力,并引入贪婪策略和鱼类聚集装置策略,提高算法搜索效率和精度。利用CEC2020测试函数对所提算法进行实验对比,验证了改进算法的性能。实验结果表明,凸包策略能有效提升算法规划能力,且与传统算法相比,改进后的算法能够使无人机的寻优精度更高,代价函数更小。
摘要为了准确地描述新能源输出功率的波动性和随机性对多能互补微网系统运行的影响,提出了基于数据驱动的多能微网鲁棒优化方法。首先,在传统区间集合的基础上对新能源出力的不确定参数进行多面体集合建模,然后利用具有时空相关性的新能源出力历史数据建立椭球不确定集合,通过连接高维椭球顶点,建立了数据驱动的凸包多面体集合,接着通过放缩凸包集合更好地对不确定参数进行包络。进一步建立了基于数据驱动的多能互补微网鲁棒优化模型,并采用列与约束生成算法(Column and constraint generation,C&CG)对该模型进行求解。最后通过算例进行仿真对比,结果表明,基于数据驱动的多能互补微网鲁棒优化方法可以减少保守性,提高优化结果鲁棒性,证明了所提方法的有效性。
基金This work is supported by the National Natural Science Foundation of China.
摘要This paper presents a new and simple scheme to describe the convex hull in R^d,which only uses three kinds of the faces of the convex hull,i.e.,the d-1-faces,d-2-faces and 0-faces.Thus,we develop an efficient new algorithm for constructing the convex hull of a finite set of points incrementally. This algorithm employs much less storage and time than that of the previously-existing approaches.The analysis of the running time as well as the storage for the new algorithm is also theoretically made.The algorithm is optimal in the worst case for even d.
基金This work was supported in part by the Natural Science Foundation of Henan Province,and the specific grant number is 232300420301。
摘要Arc grounding faults occur frequently in the power grid with small resistance grounding neutral points.The existing arc fault identification technology only uses the fault line signal characteristics to set the identification index,which leads to detection failure when the arc zero-off characteristic is short.To solve this problem,this paper presents an arc fault identification method by utilizing integrated signal characteristics of both the fault line and sound lines.Firstly,the waveform characteristics of the fault line and sound lines under an arc grounding fault are studied.After that,the convex hull,gradient product,and correlation coefficient index are used as the basic characteristic parameters to establish fault identification criteria.Then,the logistic regression algorithm is employed to deal with the reference samples,establish the machine discrimination model,and realize the discrimination of fault types.Finally,simulation test results and experimental results verify the accuracy of the proposed method.The comparison analysis shows that the proposed method has higher recognition accuracy,especially when the arc dissipation power is smaller than 2×103 W,the zero-off period is not obvious.In conclusion,the proposed method expands the arc fault identification theory.