共查询到19条相似文献,搜索用时 62 毫秒
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When the current Grover algorithm is applied to searching some targets in an unsorted quantum database, the differences of the significance for each target are not taken into consideration. When the targets are more than a quarter of the total items, the probability of finding targets rapidly falls with the increase of the targets, and when the targets are more than half of the total items, the algorithm will be invalidated. Aiming at these problems, flrstly, an improvement based on the weighted targets is proposed in which each target is endowed a weight coefficient according to its significance. Using these different weight coefficients, we give a quantum superposition of all target states, which may make the probability for each target equal to its weight coefficient. Secondly, an improved phase matching is proposed in which two directions of phase rotation are same, and two magnitudes are determined by the inner product of the superposition of target states and the initial system state. When this inner product is more than 1/2, using the improved phase matching. The targets can be found with a probability of 100% and by the only one Grover iteration. Finally, the validity of these measures is validated by a simple searching example. 相似文献
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量子菌群算法是将量子计算与菌群觅食优化算法相融合而得到的一种量子智能算法,但该算法存在鲁棒性比较差和寻优时间比较长的缺陷。为解决该问题,本文设计了一种旋转相位自适应调整的量子旋转门,并用其完成细菌的趋化操作,提出了一种自适应相位旋转的量子菌群算法。通过16个不同类型的标准测试函数对其优化性能进行研究,统计结果表明该算法在低维时,对于多种种类的测试函数,在收敛精度和稳定性上都要优于改进前的量子菌群算法,且优化结果要明显优于经典的菌群觅食优化算法和量子遗传算法。进一步研究表明,在达到指定收敛精度的情况下,该算法的平均收敛概率是最高的,平均运行时间和平均迭代步数是最短的。而在高维情况下,该算法则对碗状和碟状类型的测试函数比较适用。 相似文献
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LUO Wenjun LIU Guanli 《中国通信》2014,(9):104-111
Quantum cryptography and quantum search algorithm are considered as two important research topics in quantum information science. An asymmetrical quantum encryption protocol based on the properties of quantum one-way function and quantum search algorithm is proposed. Depending on the no-cloning theorem and trapdoor one-way functions of the public- key, the eavesdropper cannot extract any private-information from the public-keys and the ciphertext. Introducing key-generation randomized logarithm to improve security of our proposed protocol, i.e., one private- key corresponds to an exponential number of public-keys. Using unitary operations and the single photon measurement, secret messages can be directly sent from the sender to the receiver. The security of the proposed protocol is proved that it is informationtheoretically secure. Furthermore, compared the symmetrical Quantum key distribution, the proposed protocol is not only efficient to reduce additional communication, but also easier to carry out in practice, because no entangled photons and complex operations are required. 相似文献
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DNA复制和蛋白质合成过程中的核苷酸基配对过程可以看成是无序数据项的搜索问题.量子搜索与经典搜索相比,具有平方根数量级的加速.本文通过符合Grover量子搜索算法的经典谐振子系统和量子隧道效应建立了核甘酸基配对和氢键形成的模型,并从维持量子相干性的角度探讨了DNA聚合酶的催化作用,从信息学的角度论证了生物信息处理的优化. 相似文献
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一种有效的基于并行量子进化算法的图像边缘检测方法 总被引:14,自引:0,他引:14
本文基于费用函数最小化方法,提出一种混合并行量子进化算法用于文本图像的边缘检测。量子进化算法是一种基于量予计算的概念和理论(诸如量子比特和量子叠加态)的进化算法,它采用了量子编码来表征染色体,由于量子比特的概率表示,能够表示出解的线性叠加状态。此外,量子进化算法具有收敛快和好的全局搜索特性,因此它比传统的进化算法更适于并行结构的实现。我们将这一算法和局部搜索算法相结合,用于图像的边缘检测问题,得到了令人满意的检测效果,并对噪声有较好的抑制作用。 相似文献
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提出了一种多宇宙并行量子遗传算法,并从理论上证明了算法的全局收敛性.算法中将所有的个体按照一定的拓扑结构分成一个个独立的子群体,称为宇宙;采用多状态基因量子比特编码方式来表达宇宙中的个体;采用通用的量子旋转门策略和动态调整旋转角机制对个体进行演化;采用量子非门实现量子变异以阻止早熟收敛;各宇宙独立演化,宇宙之间采用最佳移民和量子交叉操作来交换信息,提高算法的执行效率.将该算法与独立分量分析算法相结合,提出一种盲源分离新方法.仿真结果表明:新方法比采用常规遗传算法和量子遗传算法的盲源分离方法具有明显的高效性. 相似文献
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运动估计中一种基于分级搜索的快速菱形算法 总被引:1,自引:1,他引:0
文章在分析菱形算法的基础上,设计了一种区分出运动剧烈和缓慢的视频帧分析方法.在此基础上针对大部分的运动缓慢帧提出了一种新的搜索模板。实验结果表明,该方法同菱形搜索算法相比.可在基本不降低搜索效果的情况下极大的提高搜索效率。 相似文献
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