For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. ...For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. [Phys. Rev. Lett.113 210501(2014)] claimed that the quadratic speedup over classical algorithms has been achieved. However, in this paper, we point out that this is not the case, because the query complexity of Yoder’s algorithm is actually in O(1/λ01/2)rather than O(1/λ1/2), where λ0 is a known lower bound of λ.(ii) In terms of the trail-and-error method, currently the algorithm without randomness has to take more than 1 times queries or iterations than the algorithm with randomly selected parameters. For the above problems, we provide the first hybrid quantum search algorithm based on the fixed-point and trail-and-error methods, where the matched multiphase Grover operations are trialed multiple times and the number of iterations increases exponentially along with the number of trials. The upper bound of expected queries as well as the optimal parameters are derived. Compared with Yoder’s algorithm, the query complexity of our algorithm indeed achieves the optimal scaling in λ for quantum search, which reconfirms the practicality of the fixed-point method. In addition, our algorithm also does not contain randomness, and compared with the existing deterministic algorithm, the query complexity can be reduced by about 1/3. Our work provides a new idea for the research on fixed-point and trial-and-error quantum search.展开更多
为了提高对管制物品的检测精度,本文提出一种结合RFB(receptive field block)网络结构和特征融合的目标检测算法。首先对采集的安检数据进行无效内容剔除、滤波;接着对安检数据进行人工标注和数据增强;然后在MobileNetV3-SSD算法的基础...为了提高对管制物品的检测精度,本文提出一种结合RFB(receptive field block)网络结构和特征融合的目标检测算法。首先对采集的安检数据进行无效内容剔除、滤波;接着对安检数据进行人工标注和数据增强;然后在MobileNetV3-SSD算法的基础上,通过引入RFB网络改进其网络结构,以加强网络的特征提取能力,并利用特征融合的方法提高模型的小目标检测能力;最后,构建了一个安检数据集SCCI2020来验证算法的性能,该数据集包含91767张图片。实验结果表明,本算法在安检数据集SCCI2020上的检测精度为87.0%,比MobileNetV3-SSD算法的检测精度高2.7个百分点;在COCO2014和COCO2017通用数据集上的检测精度分别为21.9%和23%,相对于VGG16-SSD、MobileNetV3-SSD算法均有一定提升。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11504430 and 61502526)the National Basic Research Program of China(Grant No.2013CB338002)
文摘For the unsorted database quantum search with the unknown fraction λ of target items, there are mainly two kinds of methods, i.e., fixed-point and trail-and-error.(i) In terms of the fixed-point method, Yoder et al. [Phys. Rev. Lett.113 210501(2014)] claimed that the quadratic speedup over classical algorithms has been achieved. However, in this paper, we point out that this is not the case, because the query complexity of Yoder’s algorithm is actually in O(1/λ01/2)rather than O(1/λ1/2), where λ0 is a known lower bound of λ.(ii) In terms of the trail-and-error method, currently the algorithm without randomness has to take more than 1 times queries or iterations than the algorithm with randomly selected parameters. For the above problems, we provide the first hybrid quantum search algorithm based on the fixed-point and trail-and-error methods, where the matched multiphase Grover operations are trialed multiple times and the number of iterations increases exponentially along with the number of trials. The upper bound of expected queries as well as the optimal parameters are derived. Compared with Yoder’s algorithm, the query complexity of our algorithm indeed achieves the optimal scaling in λ for quantum search, which reconfirms the practicality of the fixed-point method. In addition, our algorithm also does not contain randomness, and compared with the existing deterministic algorithm, the query complexity can be reduced by about 1/3. Our work provides a new idea for the research on fixed-point and trial-and-error quantum search.
文摘为了提高对管制物品的检测精度,本文提出一种结合RFB(receptive field block)网络结构和特征融合的目标检测算法。首先对采集的安检数据进行无效内容剔除、滤波;接着对安检数据进行人工标注和数据增强;然后在MobileNetV3-SSD算法的基础上,通过引入RFB网络改进其网络结构,以加强网络的特征提取能力,并利用特征融合的方法提高模型的小目标检测能力;最后,构建了一个安检数据集SCCI2020来验证算法的性能,该数据集包含91767张图片。实验结果表明,本算法在安检数据集SCCI2020上的检测精度为87.0%,比MobileNetV3-SSD算法的检测精度高2.7个百分点;在COCO2014和COCO2017通用数据集上的检测精度分别为21.9%和23%,相对于VGG16-SSD、MobileNetV3-SSD算法均有一定提升。
