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
The algorithms of convex hull have been extensively studied in literature, principally because of their wide range of applications in different areas. This article presents an efficient algorithm to construct approxim...The algorithms of convex hull have been extensively studied in literature, principally because of their wide range of applications in different areas. This article presents an efficient algorithm to construct approximate convex hull from a set of n points in the plane in O(n+k) time, where k is the approximation error control parameter. The proposed algorithm is suitable for applications preferred to reduce the computation time in exchange of accuracy level such as animation and interaction in computer graphics where rapid and real-time graphics rendering is indispensable.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
We consider the problem of guillotine cutting a rectangular sheet into rectangular pieces with two heights. A polynomial time algorithm for this problem is constructed.
面向基于冷热电联供系统和热网构建的多区域综合能源系统(integrated energy system,IES),该文提出计及热网蓄热特性的多区域IES多元储能规划方法。首先,基于能量守恒方程推导热网蓄热模型,以量化热网的缓冲能力;在此基础上,以年综合成...面向基于冷热电联供系统和热网构建的多区域综合能源系统(integrated energy system,IES),该文提出计及热网蓄热特性的多区域IES多元储能规划方法。首先,基于能量守恒方程推导热网蓄热模型,以量化热网的缓冲能力;在此基础上,以年综合成本最小为目标,建立计及热网蓄热特性的多区域IES多元储能规划模型;然后,针对区域互联热网管道流量变化导致模型非凸的问题,利用凸包方法将模型转凸,并设计自适应求解策略,提出凸包自适应优化算法以实现模型的有效求解。最后,天津某实际多区域IES的规划仿真和分析验证了该文所提模型和算法的有效性。展开更多
文摘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.
文摘The algorithms of convex hull have been extensively studied in literature, principally because of their wide range of applications in different areas. This article presents an efficient algorithm to construct approximate convex hull from a set of n points in the plane in O(n+k) time, where k is the approximation error control parameter. The proposed algorithm is suitable for applications preferred to reduce the computation time in exchange of accuracy level such as animation and interaction in computer graphics where rapid and real-time graphics rendering is indispensable.
基金This work was supported in part by the Natural Science Foundation of Henan Province,and the specific grant number is 232300420301。
文摘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.
文摘We consider the problem of guillotine cutting a rectangular sheet into rectangular pieces with two heights. A polynomial time algorithm for this problem is constructed.
文摘面向基于冷热电联供系统和热网构建的多区域综合能源系统(integrated energy system,IES),该文提出计及热网蓄热特性的多区域IES多元储能规划方法。首先,基于能量守恒方程推导热网蓄热模型,以量化热网的缓冲能力;在此基础上,以年综合成本最小为目标,建立计及热网蓄热特性的多区域IES多元储能规划模型;然后,针对区域互联热网管道流量变化导致模型非凸的问题,利用凸包方法将模型转凸,并设计自适应求解策略,提出凸包自适应优化算法以实现模型的有效求解。最后,天津某实际多区域IES的规划仿真和分析验证了该文所提模型和算法的有效性。