Choosing particular solution source and its position have great influence on accu- racy of sound field prediction in distributed source boundary point method. An optimization method for determining the position of par...Choosing particular solution source and its position have great influence on accu- racy of sound field prediction in distributed source boundary point method. An optimization method for determining the position of particular solution sources is proposed to get high accu- racy prediction result. In this method, tripole is chosen as the particular solution. The upper limit frequency of calculation is predicted by setting 1% volume velocity relative error limit using vibration velocity of structure surface. Then, the optimal position of particular solution sources, in which the relative error of volume velocity is minimum, is determined within the range of upper limit frequency by searching algorithm using volume velocity matching. The transfer matrix between pressure and surface volume velocity is constructed in the optimal position. After that, the sound radiation of structure is calculated by the matrix. The results of numerical simulation show that the calculation error is significantly reduced by the proposed method. When there are vibration velocity measurement errors, the calculation errors can be controlled within 5% by the method.展开更多
We present a new method to determine the optimal regularity of positive solutions u∈C^(4)(Ω\{0})∩C^(0)(Ω) of the Hénon-Hardy equation,i.e.,Δ^(2)u=|x|^(α)u^(p)inΩ,(0,1) where Ω■RN(N≥4) is a bounded smoot...We present a new method to determine the optimal regularity of positive solutions u∈C^(4)(Ω\{0})∩C^(0)(Ω) of the Hénon-Hardy equation,i.e.,Δ^(2)u=|x|^(α)u^(p)inΩ,(0,1) where Ω■RN(N≥4) is a bounded smooth domain with 0∈Ω,α>-4,and p∈R.It is clear that 0 is an isolated singular point of solutions of(0.1) and the optimal regularity of u in Ω relies on the parameter α.It is also important to see that the regularity of u at x=0 determines the regularity of u in Ω.We first establish asymptotic expansions up to arbitrary orders at x=0 of prescribed positive solutions u ∈C^(4)(Ω{0}) ∩ C^(0)(Ω)of(0.1).Then we show that the regularity at x=0 of each positive solution u of(0.1) can be determined by some terms in asymptotic expansions of the related positive radial solution of the equation(0.1) with Ω=B,where B is the unit ball of R^(N).The main idea works for more general equations with singular weights.展开更多
为了解决传统光伏阵列最大功率点追踪(maximum power point tracking,MPPT)算法易陷入局部最大功率点(local maximum power point,LMPP)的问题,本文提出一种基于自适应位置调节的飞蛾扑火(adaptive position adjustment for moth-flame ...为了解决传统光伏阵列最大功率点追踪(maximum power point tracking,MPPT)算法易陷入局部最大功率点(local maximum power point,LMPP)的问题,本文提出一种基于自适应位置调节的飞蛾扑火(adaptive position adjustment for moth-flame optimization algorithm,AMFO)MPPT控制方法,该方法在飞蛾的位置更新机制中引入自适应位置插值策略和自适应权重因子策略,提高了算法的求解精度和优化速度,使之不易陷入局部最大功率点。将改进后的算法应用于光伏系统MPPT中,仿真实验结果表明:改进后的算法相较于传统的飞蛾扑火优化(moth-flame optimization,MFO)算法、灰狼优化(grey wolf optimizer,GWO)算法和粒子群优化(particle swarm optimization,PSO)算法,在均匀光照和局部遮阴条件下的追踪速率和精度均有较大提升。展开更多
文摘Choosing particular solution source and its position have great influence on accu- racy of sound field prediction in distributed source boundary point method. An optimization method for determining the position of particular solution sources is proposed to get high accu- racy prediction result. In this method, tripole is chosen as the particular solution. The upper limit frequency of calculation is predicted by setting 1% volume velocity relative error limit using vibration velocity of structure surface. Then, the optimal position of particular solution sources, in which the relative error of volume velocity is minimum, is determined within the range of upper limit frequency by searching algorithm using volume velocity matching. The transfer matrix between pressure and surface volume velocity is constructed in the optimal position. After that, the sound radiation of structure is calculated by the matrix. The results of numerical simulation show that the calculation error is significantly reduced by the proposed method. When there are vibration velocity measurement errors, the calculation errors can be controlled within 5% by the method.
基金supported by National Natural Science Foundation of China (Grant No. 11571093)supported by the Fundamental Research Funds for the Central Universities (Grant No. WK0010000064)Anhui Provincial Natural Science Foundation (Grant No. BJ0010000026)。
文摘We present a new method to determine the optimal regularity of positive solutions u∈C^(4)(Ω\{0})∩C^(0)(Ω) of the Hénon-Hardy equation,i.e.,Δ^(2)u=|x|^(α)u^(p)inΩ,(0,1) where Ω■RN(N≥4) is a bounded smooth domain with 0∈Ω,α>-4,and p∈R.It is clear that 0 is an isolated singular point of solutions of(0.1) and the optimal regularity of u in Ω relies on the parameter α.It is also important to see that the regularity of u at x=0 determines the regularity of u in Ω.We first establish asymptotic expansions up to arbitrary orders at x=0 of prescribed positive solutions u ∈C^(4)(Ω{0}) ∩ C^(0)(Ω)of(0.1).Then we show that the regularity at x=0 of each positive solution u of(0.1) can be determined by some terms in asymptotic expansions of the related positive radial solution of the equation(0.1) with Ω=B,where B is the unit ball of R^(N).The main idea works for more general equations with singular weights.
文摘为了解决传统光伏阵列最大功率点追踪(maximum power point tracking,MPPT)算法易陷入局部最大功率点(local maximum power point,LMPP)的问题,本文提出一种基于自适应位置调节的飞蛾扑火(adaptive position adjustment for moth-flame optimization algorithm,AMFO)MPPT控制方法,该方法在飞蛾的位置更新机制中引入自适应位置插值策略和自适应权重因子策略,提高了算法的求解精度和优化速度,使之不易陷入局部最大功率点。将改进后的算法应用于光伏系统MPPT中,仿真实验结果表明:改进后的算法相较于传统的飞蛾扑火优化(moth-flame optimization,MFO)算法、灰狼优化(grey wolf optimizer,GWO)算法和粒子群优化(particle swarm optimization,PSO)算法,在均匀光照和局部遮阴条件下的追踪速率和精度均有较大提升。
