共查询到20条相似文献,搜索用时 156 毫秒
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针对放大转发(AF)的多源多中继两跳协作通信网络模型,提出了一种基于轮询分组调度算法的节点选择与用户调度策略.与之前所提出的中继选择选择算法相比,所提出的中继节点轮询分组调度算法,不需要额外的信令开销,复杂度低,并保证中继间的负载均衡.此外,为保证用户传输的公平性,提出一种结合多用户分集的轮询分组调度算法.最后在已选择的中继节点和所调度的源节点用户中引入分布式空时编码.仿真结果表明,该节点选择和用户调度算法能保证所有节点使用的公平性,并且结合分布式空时编码之后,可以提高频谱利用率,从而提高了系统性能. 相似文献
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针对正交频分多址接入(OFDMA)系统下行链路的混合业务调度问题,提出了一种基于队列等待时间的跨层调度算法.该算法联合利用了MAC层的队列等待时间与物理层的信道状态信息作为调度参数,通过队列等待时间反映用户的服务质量要求,并利用多用户分集增益提高系统性能;针对实时和非实时用户的不同服务质量要求,在队列等待时间的计算上采取了不同的策略;在子载波的分配过程中根据分配状态及时更新队列等待时间,使资源的利用更为有效.仿真结果表明,提出的算法可显著降低实时用户的平均时延和最大延时违反概率,同时保证了非实时用户的吞吐量需求,能够有效地支持下一代网络中混合业务的多种服务质量要求. 相似文献
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针对多用户协同无线网络中的中继选择问题,提出了两种基于不同系统开销的半分布式中继选择算法。这两种算法以中断概率为优化目标,充分利用多用户协同无线网络的特点,以较低的系统开销和计算复杂度获取使系统中断概率达到最小的中继选择问题(指派问题)的次优解。仿真结果表明,两种算法均可以较好地逼近中断概率性能的下界,并保证用户公平性,而算法2以较大的系统开销换取优于算法1的容量性能。提出的两种半分布式算法在性能和系统开销之间获得了较好的折衷,可以大幅简化中继选择在实际无线通信系统中的应用,尤其适用于稠密人口地区的应用。 相似文献
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为克服正交频分复用(OFDM)系统中因时变多径衰落信道破坏子载波的正交性引起载波间干扰(ICI),从而导致系统性能下降的问题,提出了一种基于最小均方误差(MMSE)估计和迭代算法相结合的迭代干扰抵消算法.为了消除一般MMSE均衡方法将载波间干扰当作加性高斯白噪声(AWGN)所带来的误差,该算法先使用MMSE方法对传输信号进行初值估计,再通过迭代干扰抵消和MMSE均衡相结合,来消除由时变信道所带来的载波间干扰.多次仿真表明,在时变多径衰落信道中使用本算法能够有效地消除载波间干扰,使系统性能得到很好的改善. 相似文献
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Chuanli Wang En Zhu Xinwang Liu Jiaohua Qin Jianping Yin Kaikai Zhao 《计算机、材料和连续体(英文)》2019,61(1):409-421
Multiple kernel clustering based on local kernel alignment has achieved outstanding clustering performance by applying local kernel alignment on each sample. However, we observe that most of existing works usually assume that each local kernel alignment has the equal contribution to clustering performance, while local kernel alignment on different sample actually has different contribution to clustering performance. Therefore this assumption could have a negative effective on clustering performance. To solve this issue, we design a multiple kernel clustering algorithm based on self-weighted local kernel alignment, which can learn a proper weight to clustering performance for each local kernel alignment. Specifically, we introduce a new optimization variable- weight-to denote the contribution of each local kernel alignment to clustering performance, and then, weight, kernel combination coefficients and cluster membership are alternately optimized under kernel alignment frame. In addition, we develop a three-step alternate iterative optimization algorithm to address the resultant optimization problem. Broad experiments on five benchmark data sets have been put into effect to evaluate the clustering performance of the proposed algorithm. The experimental results distinctly demonstrate that the proposed algorithm outperforms the typical multiple kernel clustering algorithms, which illustrates the effectiveness of the proposed algorithm. 相似文献
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模拟退火和并行遗传算法是两种较好的改进进化算法性能的方法。将这两种思想有机地结合起来,利用遗传算法能全局寻优的优势和模拟退火算法的爬山性能,提出了一种基于模拟退火并行遗传算法的Otsu双阈值医学图像分割算法。在该算法中,进化在多个不同的子群中并行进行,利用模拟退火算法的爬山性能,避免单种群进化过程中出现的过早收敛现象,提高整个算法的收敛速度。实验证明,这种新的图像分割算法与并行遗传算法相比,不仅能够对图像进行准确的分割,而且具有更强的精确性和稳定性。其收敛速度明显比并行遗传算法的Otsu双阈值医学图像分割快。 相似文献
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目的为了解决传统单PID控制优化算法仅关注跟踪性能,无法满足在纸浆浓度控制系统等工业生产环节中控制品质和成品良率的需求。方法将PID控制系统离散化以计算在高斯扰动下的输出方差作为扰动抑制的依据,并结合ITAE指标通过差分进化算法优化PID性能。结果仿真表明,该整定方法可以通过权值选取优化的偏好,自由调节PID控制器的性能表现,对比基于Z-N法的PID控制和基于PSO算法优化的PID控制,基于扰动抑制差分进化算法的PID控制的ITAE指标为14.3495,输出方差为31.8530,均优于其他2种算法。结论基于扰动抑制的差分进化算法可以通过用户自定义权重来协调纸浆浓度的输出方差和跟踪性能,从更实际的角度整定纸浆浓度控制系统的PID控制器参数,使得控制系统的性能指标满足工业生产要求。 相似文献
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Experiments with hybrid Bernstein global optimization algorithm for the OPF problem in power systems
Bhagyesh V. Patil L.P.M.I. Sampath Ashok Krishnan J. M. Maciejowski K. V. Ling H. B. Gooi 《工程优选》2019,51(8):1446-1461
This article presents an algorithm based on the Bernstein form of polynomials for solving the optimal power flow (OPF) problem in electrical power networks. The proposed algorithm combines local and global optimization methods and is therefore referred to as a ‘hybrid’ Bernstein algorithm in the context of this work. The proposed algorithm is a branch-and-bound procedure wherein a local search method is used to obtain a good upper bound on the global minimum at each branching node. Subsequently, the Bernstein form of polynomials is used to obtain a lower bound on the global minimum. The performance of the proposed algorithm is compared with the previously reported Bernstein algorithm to demonstrate its efficacy in terms of the chosen performance metrics. Furthermore, the proposed algorithm is tested on the OPF problem for several benchmark IEEE power system examples and its performance is compared with generic global optimization solvers such as BARON and COUENNE. The test results demonstrate that the hybrid Bernstein global optimization algorithm delivers satisfactory performance in terms of solution optimality. 相似文献
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R. Venkata Rao 《工程优选》2017,49(1):60-83
This article presents the performance of a very recently proposed Jaya algorithm on a class of constrained design optimization problems. The distinct feature of this algorithm is that it does not have any algorithm-specific control parameters and hence the burden of tuning the control parameters is minimized. The performance of the proposed Jaya algorithm is tested on 21 benchmark problems related to constrained design optimization. In addition to the 21 benchmark problems, the performance of the algorithm is investigated on four constrained mechanical design problems, i.e. robot gripper, multiple disc clutch brake, hydrostatic thrust bearing and rolling element bearing. The computational results reveal that the Jaya algorithm is superior to or competitive with other optimization algorithms for the problems considered. 相似文献
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Fernando Hernando Michael O’Sullivan Diego Ruano 《Applicable Algebra in Engineering, Communication and Computing》2013,24(3-4):237-253
Assuming that we have a soft-decision list decoding algorithm of a linear code, a new hard-decision list decoding algorithm of its repeated code is proposed in this article. Although repeated codes are not used for encoding data, due to their parameters, we show that they have a good performance with this algorithm. We compare, by computer simulations, our algorithm for the repeated code of a Reed–Solomon code against a decoding algorithm of a Reed–Solomon code. Finally, we estimate the decoding capability of the algorithm for Reed–Solomon codes and show that performance is somewhat better than our estimates. 相似文献
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滤波-x最小均方(Filtered-x Least Mean Square,FxLMS)算法是主动噪声控制的经典算法,其存在收敛速度与稳态误差不可兼得的问题,解决方法之一是采用变步长FxLMS算法。总结了现有的基于误差非线性函数的变步长模型,并将其应用于FxLMS算法以改善算法性能。用三种常见的噪声作为参考输入信号进行仿真试验,对比了不同非线性函数变步长算法的性能。结果表明,变步长FxLMS算法能有效改善参考信号为高斯白噪声和正弦波时的收敛速度和稳态误差,且不同噪声环境下最优算法不同,但此类算法无法提升噪声源为冲击噪声时的性能。这为不同应用场景下算法的选取提供了参考。将变步长FxLMS算法应用于某车型的发动机主动噪声控制,结果表明,变步长FxLMS能显著提高定速工况的系统性能,但对急加速工况效果并不明显。 相似文献