为进一步提高电动车辆队列行驶的经济性、降低车用动力电池的容量衰减,对某电动货车队列开展了行驶速度规划研究.首先建立了电动货车的单车能耗模型;然后基于此单车能耗模型、固定车头间距的跟车间距策略,以及拟合得到的不同间距下队列...为进一步提高电动车辆队列行驶的经济性、降低车用动力电池的容量衰减,对某电动货车队列开展了行驶速度规划研究.首先建立了电动货车的单车能耗模型;然后基于此单车能耗模型、固定车头间距的跟车间距策略,以及拟合得到的不同间距下队列中各车的气动阻力系数,建立了队列的能耗模型;接着以队列能量消耗最低为优化目标,以行程时间和道路限速为约束,采用交替方向乘子法(Alternating Direction Method of Multipliers,ADMM)对队列进行了行驶速度规划;最后仿真研究了规划速度对队列行驶能耗和车辆动力电池容量衰减的影响.研究结果表明:相比于队列按定速巡航与基于坡度加速度的二次规划车速行驶,队列按ADMM规划车速行驶可分别使电动汽车节能9.29%和7.75%,且随着行驶里程的增加,以ADMM规划车速行驶的节能效果愈加明显;车辆队列运行1年后,ADMM规划车速行驶的电池容量衰减相比其他2种规划行驶分别下降9.69%和2.54%,即采用ADMM规划车速行驶可以减缓电池的老化速度,且随着时间的推移,在这3种行驶速度下的电池容量衰减差异越来越大.展开更多
By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the e...By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the economic dispatch problem(EDP) in power systems. Different from most of the existing distributed ED approaches which neglect the effects of packet drops or/and time delays, this paper takes into account both packet drops and time delays which frequently occur in communication networks. Moreover, directed and possibly unbalanced graphs are considered in our algorithms, over which many distributed approaches fail to converge. Furthermore, the proposed schemes can address the EDP with local constraints of generators and nonquadratic convex cost functions, not just quadratic ones required in some existing ED approaches. Both theoretical analyses and simulation studies are provided to demonstrate the effectiveness of the proposed schemes.展开更多
This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the charac...This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the characteristics of nonlinear, non-convex and non-smooth. Consequently, the numerical computation with the curvature regularization is difficult. In order to conquer the computation problem, the proposed model is transformed into an alternating optimization problem by importing auxiliary variables. Furthermore, based on alternating direction method of multipliers, we design a fast numerical approximation iterative scheme for proposed model. Finally, numerous experiments are implemented to indicate the advantages of the proposed model in image edge preserving, image contrast and corners preserving. Meanwhile, the high computational efficiency of the designed model is verified by comparing with traditional models, including the total variation(TV) and total Laplace(TL) model.展开更多
为加快故障发生后配电网供电恢复方法的求解效率,文中提出了一种基于改进交替方向乘子法(alternating direction method of multipliers,ADMM)的配电网多时段分布式供电恢复方法。以故障后最大化负荷恢复量和系统损耗最低为目标,建立了...为加快故障发生后配电网供电恢复方法的求解效率,文中提出了一种基于改进交替方向乘子法(alternating direction method of multipliers,ADMM)的配电网多时段分布式供电恢复方法。以故障后最大化负荷恢复量和系统损耗最低为目标,建立了配电网多时段供电恢复模型。引入超松弛技术和惩罚参数动态调整技术对ADMM进行改进,提出了基于自适应松弛惩罚参数ADMM的配电网多时段分布式供电恢复方法。最后在改进的IEEE-33节点系统上进行算例分析,结果表明文中所提基于自适应松弛惩罚参数ADMM具有较好的分布式计算性能。展开更多
This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation techno...This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation technologies:Area 1 combines thermal,hydro,and distributed generation;Area 2 utilizes a blend of thermal units,distributed solar technologies(DST),and hydro power;andThird control area hosts geothermal power station alongside thermal power generation unit and hydropower units.The suggested control system employs a multi-layered approach,featuring a blended methodology utilizing the Tilted Integral Derivative controller(TID)and the Fractional-Order Integral method to enhance performance and stability.The parameters of this hybrid TID-FOI controller are finely tuned using an advanced optimization method known as the Walrus Optimization Algorithm(WaOA).Performance analysis reveals that the combined TID-FOI controller significantly outperforms the TID and PID controllers when comparing their dynamic response across various system configurations.The study also incorporates investigation of redox flow batteries within the broader scope of energy storage applications to assess their impact on system performance.In addition,the research explores the controller’s effectiveness under different power exchange scenarios in a deregulated market,accounting for restrictions on generation ramp rates and governor hysteresis effects in dynamic control.To ensure the reliability and resilience of the presented methodology,the system transitions and develops across a broad range of varying parameters and stochastic load fluctuation.To wrap up,the study offers a pioneering control approach-a hybrid TID-FOI controller optimized via the Walrus Optimization Algorithm(WaOA)-designed for enhanced stability and performance in a complex,three-region hybrid energy system functioning within a deregulated framework.展开更多
稀疏重建是当前CT(computed tomography)领域的研究热点,其实质是用稀疏视角下的投影来重建图像,以减少扫描过程中对病患的辐射剂量。随着压缩感知理论的提出,稀疏重建算法已经被广泛应用到了医学CT中。TV(total variation)算法是可以...稀疏重建是当前CT(computed tomography)领域的研究热点,其实质是用稀疏视角下的投影来重建图像,以减少扫描过程中对病患的辐射剂量。随着压缩感知理论的提出,稀疏重建算法已经被广泛应用到了医学CT中。TV(total variation)算法是可以实现稀疏重建的一种有效方法。本文设计了一种基于ADMM(alternating direction method of multipliers)的TV算法,先将非约束的优化问题转换为约束形式,然后引入乘子,最后通过交替方向法实现迭代过程。该方法将复杂的优化问题分解为了若干个具有闭合形式的子优化问题,故迭代速度较快。仿真实验表明,与传统的滤波反投影算法相比,该算法可以实现稀疏角度下的高精度图像重建。同时还初步探讨了平衡因子在不同噪声情形下对重建精度的影响。展开更多
文摘针对具有星间链路(inter-satellite links,ISL)的低轨(low earth orbit,LEO)多卫星系统,提出了一种基于多卫星协作传输的和速率(sum rate,SR)最大化预编码算法.传统的预编码算法需要复杂的星上计算来得到数值解,这导致低轨卫星系统面临较大的计算开销和延迟问题.为解决上述关键问题,设计了一种基于交替方向乘子法(alternating direction method of multipliers,ADMM)的高吞吐量、低复杂度、具有闭式解的分布式预编码算法.该算法通过构建辅助变量和问题分解,将预编码设计问题转化为多个子问题并行求解,每个子问题仅有一个约束条件,并在每次迭代后仅通过星间链路交换设计的数据矩阵,从而有效实现分布式预编码.仿真结果表明,与典型的两步和速率最大化算法相比,所提出的算法可以实现更高的和速率,同时大幅降低计算复杂度.
文摘为进一步提高电动车辆队列行驶的经济性、降低车用动力电池的容量衰减,对某电动货车队列开展了行驶速度规划研究.首先建立了电动货车的单车能耗模型;然后基于此单车能耗模型、固定车头间距的跟车间距策略,以及拟合得到的不同间距下队列中各车的气动阻力系数,建立了队列的能耗模型;接着以队列能量消耗最低为优化目标,以行程时间和道路限速为约束,采用交替方向乘子法(Alternating Direction Method of Multipliers,ADMM)对队列进行了行驶速度规划;最后仿真研究了规划速度对队列行驶能耗和车辆动力电池容量衰减的影响.研究结果表明:相比于队列按定速巡航与基于坡度加速度的二次规划车速行驶,队列按ADMM规划车速行驶可分别使电动汽车节能9.29%和7.75%,且随着行驶里程的增加,以ADMM规划车速行驶的节能效果愈加明显;车辆队列运行1年后,ADMM规划车速行驶的电池容量衰减相比其他2种规划行驶分别下降9.69%和2.54%,即采用ADMM规划车速行驶可以减缓电池的老化速度,且随着时间的推移,在这3种行驶速度下的电池容量衰减差异越来越大.
基金supported by the National Natural Science Foundation of China(61673077)。
文摘By virtue of alternating direction method of multipliers(ADMM), Newton-Raphson method, ratio consensus approach and running sum method, two distributed iterative strategies are presented in this paper to address the economic dispatch problem(EDP) in power systems. Different from most of the existing distributed ED approaches which neglect the effects of packet drops or/and time delays, this paper takes into account both packet drops and time delays which frequently occur in communication networks. Moreover, directed and possibly unbalanced graphs are considered in our algorithms, over which many distributed approaches fail to converge. Furthermore, the proposed schemes can address the EDP with local constraints of generators and nonquadratic convex cost functions, not just quadratic ones required in some existing ED approaches. Both theoretical analyses and simulation studies are provided to demonstrate the effectiveness of the proposed schemes.
基金supported by the National Natural Science Foundation of China(No.61602269)the China Postdoctoral Science Foundation(No.2015M571993)+1 种基金the Shandong Provincial Natural Science Foundation of China(No.ZR2017MD004)the Qingdao Postdoctoral Application Research Funded Project
文摘This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the characteristics of nonlinear, non-convex and non-smooth. Consequently, the numerical computation with the curvature regularization is difficult. In order to conquer the computation problem, the proposed model is transformed into an alternating optimization problem by importing auxiliary variables. Furthermore, based on alternating direction method of multipliers, we design a fast numerical approximation iterative scheme for proposed model. Finally, numerous experiments are implemented to indicate the advantages of the proposed model in image edge preserving, image contrast and corners preserving. Meanwhile, the high computational efficiency of the designed model is verified by comparing with traditional models, including the total variation(TV) and total Laplace(TL) model.
文摘为加快故障发生后配电网供电恢复方法的求解效率,文中提出了一种基于改进交替方向乘子法(alternating direction method of multipliers,ADMM)的配电网多时段分布式供电恢复方法。以故障后最大化负荷恢复量和系统损耗最低为目标,建立了配电网多时段供电恢复模型。引入超松弛技术和惩罚参数动态调整技术对ADMM进行改进,提出了基于自适应松弛惩罚参数ADMM的配电网多时段分布式供电恢复方法。最后在改进的IEEE-33节点系统上进行算例分析,结果表明文中所提基于自适应松弛惩罚参数ADMM具有较好的分布式计算性能。
文摘This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation technologies:Area 1 combines thermal,hydro,and distributed generation;Area 2 utilizes a blend of thermal units,distributed solar technologies(DST),and hydro power;andThird control area hosts geothermal power station alongside thermal power generation unit and hydropower units.The suggested control system employs a multi-layered approach,featuring a blended methodology utilizing the Tilted Integral Derivative controller(TID)and the Fractional-Order Integral method to enhance performance and stability.The parameters of this hybrid TID-FOI controller are finely tuned using an advanced optimization method known as the Walrus Optimization Algorithm(WaOA).Performance analysis reveals that the combined TID-FOI controller significantly outperforms the TID and PID controllers when comparing their dynamic response across various system configurations.The study also incorporates investigation of redox flow batteries within the broader scope of energy storage applications to assess their impact on system performance.In addition,the research explores the controller’s effectiveness under different power exchange scenarios in a deregulated market,accounting for restrictions on generation ramp rates and governor hysteresis effects in dynamic control.To ensure the reliability and resilience of the presented methodology,the system transitions and develops across a broad range of varying parameters and stochastic load fluctuation.To wrap up,the study offers a pioneering control approach-a hybrid TID-FOI controller optimized via the Walrus Optimization Algorithm(WaOA)-designed for enhanced stability and performance in a complex,three-region hybrid energy system functioning within a deregulated framework.
文摘稀疏重建是当前CT(computed tomography)领域的研究热点,其实质是用稀疏视角下的投影来重建图像,以减少扫描过程中对病患的辐射剂量。随着压缩感知理论的提出,稀疏重建算法已经被广泛应用到了医学CT中。TV(total variation)算法是可以实现稀疏重建的一种有效方法。本文设计了一种基于ADMM(alternating direction method of multipliers)的TV算法,先将非约束的优化问题转换为约束形式,然后引入乘子,最后通过交替方向法实现迭代过程。该方法将复杂的优化问题分解为了若干个具有闭合形式的子优化问题,故迭代速度较快。仿真实验表明,与传统的滤波反投影算法相比,该算法可以实现稀疏角度下的高精度图像重建。同时还初步探讨了平衡因子在不同噪声情形下对重建精度的影响。
