基于二阶锥规划的共形阵列宽带方向图综合

针对目前共形阵列方向图综合算法中全局优化算法计算复杂度高,已有凸优化算法不能处理宽带信号的问题,提出了一种基于二阶锥规划的共形阵列宽带恒定束宽方向图综合方法。该算法首先推导并建立了更为简单的共形阵列宽带信号模型;然后在频域上构造空间响应变化约束,并在空域上构造方向图的目标函数和约束条件;最后利用二阶锥规划求得最优权矢量,实现宽带信号方向图综合。理论分析和仿真结果表明,该方法能够有效地获得期望信号并抑制干扰信号,在计算复杂度上低于全局优化算法,且阵列响应具有良好的频率一致性。     

基于双迭代与二阶锥规划的机载雷达稳健降维STAP方法

针对机载雷达空时自适应处理（STAP）中期望目标导向矢量的失配问题,提出一种基于双迭代与二阶锥规划的稳健降维STAP方法。该方法首先将权矢量分解为空域与时域两个低维权矢量的Kronecker积,然后分别限定实际空域、时域导向矢量与假定导向矢量之间的误差范数边界,并通过对各自最差性能进行优化,转化为相应的SOCP形式,进而利用双迭代算法实现了对两个低维权矢量的分别求解,最终合成全维STAP权矢量。该方法在保证稳健STAP性能的同时,通过双迭代降维处理,能够有效降低训练样本数需求与运算复杂度,因此更具有实际应用价值。仿真结果验证了算法的有效性。     

计及VSC和DFIG的电网动态无功优化模型

近年来,一系列特高压直流工程的投运和大型风电场等新能源的并网给特高压近区电网无功控制带来了新的挑战。为解决含柔性直流的交直流混联电网的无功优化控制问题,提出了含电压源换流器(Voltage Source Converter, VSC)并考虑双馈感应风机(Doubly-Fed Induction Generator, DFIG)无功支撑的动态无功优化模型。该模型以交直流电网全天网损最小为目标函数,约束包括交直流系统的潮流约束、直流变量的控制约束、离散控制变量动态调节次数约束及节点电压的安全约束。原模型是一个多时段非线性混合整数规划问题,缺乏快速有效的求解方法,通过线性化技术将原模型转化为能有效求解的二阶锥规划(Second Order Cone Programming, SOCP)问题。以IEEE30节点系统为例,通过仿真计算验证了所建模型和算法的有效性。     

一种二阶锥规划通带线性相位FIR滤波器的设计

在有限冲激响应（Finite Impulse Response,FIR）滤波器设计中,如果系统只要求通带或某个频域区间具有线性相位而其他频域区间相位非线性,则系数对称的FIR滤波器设计方法不再适用。为此,提出了一种基于二阶锥规划（Second-Order Cone Programming,SOCP）的通带线性相位FIR滤波器设计方法。该方法使用二阶锥规划实现滤波器设计,其中优化目标为通带最小群延迟,约束条件为全频域振幅误差。实验结果显示,所提方法设计的FIR滤波器有着很好的幅频特性和通带线性相位,通带群延迟误差很小。该方法实现简单,计算复杂度低,可以广泛应用于数字信号处理领域。     

Lift-and-project MVEE based convex hull for robust SCED with wind power integration using historical data-driven modeling approach

This paper presents an adjustable robust security constrained economic dispatch (SCED) model with wind power uncertainties. First, the scenario based adjustable robust SCED model is presented. It considers multiple scenarios from historical data as well as the spatial correlation among wind farms. Then, the proposed SCED model becomes an optimization problem with a large amount of constraints which is skillfully solved using a lift-and-project minimum volume enclosing ellipsoid (MVEE) based convex hull. Furthermore, the proposed model is transformed into a second order cone programming (SOCP) model by the use of participation factors to generate adjustable generation outputs and thus guarantee the energy balance. In order to further reduce the computational complexity, the inactive constraints reduction strategy is proposed to quickly eliminate inactive SOC security constraints before solving the model. Numerical results of IEEE 14-bus and 118-bus test systems as well as the practical Polish power systems with several wind farms show that the proposed model can achieve better economies. Moreover, more than 82% of security constraints are identified as inactive in various cases of the simulation, and the proposed inactive constraints reduction strategy is promising for improving the computational performance.     

Distributed algorithm for target localization in wireless sensor networks using RSS and AoA measurements

This paper addresses target localization problem in a cooperative 3-D wireless sensor network (WSN). We employ a hybrid system that fuses distance and angle measurements, extracted from the received signal strength (RSS) and angle-of-arrival (AoA) information, respectively. Based on range measurement model and simple geometry, we derive a novel non-convex estimator based on the least squares (LS) criterion. The derived non-convex estimator tightly approximates the maximum likelihood (ML) one for small noise levels. We show that the developed non-convex estimator is suitable for distributed implementation, and that it can be transformed into a convex one by applying a second-order cone programming (SOCP) relaxation technique. We also show that the developed non-convex estimator can be transformed into a generalized trust region sub-problem (GTRS) framework, by following the squared range (SR) approach. The proposed SOCP algorithm for known transmit powers is then generalized to the case where the transmit powers are different and not known. Furthermore, we provide a detailed analysis of the computational complexity of the proposed algorithms. Our simulation results show that the new estimators have excellent performance in terms of the estimation accuracy and convergence, and they confirm the effectiveness of combining two radio measurements.     

Extended finite element method for plastic limit load computation of cracked structures

The extended finite element method is extended to allow computation of the limit load of cracked structures. In the paper, it is demonstrated that the linear elastic tip enrichment basis with and without radial term may be used in the framework of limit analysis, but the six‐function enrichment basis based on the well‐known Hutchinson–Rice–Rosengren asymptotic fields appears to be the best. The discrete kinematic formulation is cast in the form of a second‐order cone problem, which can be solved using highly efficient interior‐point solvers. Finally, the proposed numerical procedure is applied to various benchmark problems, showing that the present results are in good agreement with those in the literature. Copyright © 2015 John Wiley & Sons, Ltd.     

基于迭代二阶锥的唯相位波束形成

唯相位自适应波束形成技术对普通相控阵雷达自适应干扰抑制是非常重要的,在数字阵列雷达中,唯相位技术则可以充分利用各阵元发射模块微波功率从而提高雷达的威力。该文提出了一种新的唯相位波束形成方法,假定初始唯相位权重矢量有个较小的相位扰动,将唯相位模型的目标函数和约束函数在该相位扰动区域内分别用泰勒一阶展开式来近似,则可以将原来的非凸问题转化为凸优化问题,通过二阶锥规划方法(SOCP)求得使当前目标函数最小的扰动矢量,然后更新得到新的权重矢量并代替原来的权重矢量,重复上述迭代过程直到满足停止条件,可以得到满足要求的唯相位权重。计算机仿真结果验证了该方法的正确性和有效性。     

一种基于高分辨距离像数据的稳健检测算法

摘要：针对逆合成孔径雷达目标的检测问题,提出了一种对高分辨距离像数据检测的稳健算法.本文采用改进的二阶锥规划对各个距离单元的信号进行估计,并推导出改进的稳健广义似然比检测算子.分析了新算法的计算复杂度,证明了恒虚警率性,并估计了检测门限.三类飞机实测数据的多个实验结果表明,在严重导向矢量失配的情况下,本文算法性能相对与传统的广义似然比算法有明显的提高.     

基于二阶锥规划的HRTF波束形成合成方法

利用宽带波束形成器输出合成了HRTF数据.确立了波束形成器结构,建立了HRTF合成的最优问题,采用二阶锥规划最优方法得到了波束形成器的最优权向量,进而利用波束形成器的输出得到HRTF合成数据.同时结合MIT实验室的HRTF测量数据的基本特性,在求解最优问题的过程中利用了HRTF的最小相位表示,进一步降低了滤波器阶次,简化了波束形成器结构.计算机仿真和主观听觉定位实验表明,在一定频段内该方法得到的HRTF合成近似值和测量数据具有较好的一致性,验证了该方法的有效性.