共查询到20条相似文献,搜索用时 31 毫秒
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The effectiveness of deep learning networks in detecting small objects is limited, thereby posing challenges in addressing practical object detection tasks. In this research, we propose a small object detection model that operates at multiple scales. The model incorporates a multi-level bidirectional pyramid structure, which integrates deep and shallow networks to simultaneously preserve intricate local details and augment global features. Moreover, a dedicated multi-scale detection head is inte... 相似文献
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Kawther M Musthaf Azura Hamzah Ooi Wei Ling Ahmad Haziq Aiman Rosol Norliza Mohame Sulaiman Wadi Harun 《光电子快报》2024,20(6):321-329
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Deep learning (DL) based semantic segmentation methods can extract object information including category, location and shape. In this paper, the identification of prohibited items is regarded as a task of semantic segmentation, and proposes a universal model with automatic identification of prohibited items. This model has two improvements based on the general semantic segmentation network. Firstly, the N-type encoding structure is applied to enlarge the receptive field of the network aiming at reducing the misclassification. Secondly, consider the lack of surface texture in X-ray security images. Inspired by feature reuse in Densenet, shallow semantic information is reused to improve the segmentation accuracy. With the use of this model, when using input images of size 512×512, we could achieve 0.783 mean intersection over union (mIoU) for a seven-class object recognition problem. 相似文献
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安检是保障人民生命财产安全的第一道防线,智能安检是安检行业未来发展的必然趋势。X光安检图像存在背景复杂、违禁品尺度多样以及相互遮挡现象,导致传统的目标检测算法无法获得满意的效果。本文在一阶段目标检测网络SSD框架的基础上,提出了适用于X光安检图像多尺度违禁品检测网络——非对称卷积多视野神经网络ACMNet(Asymmetrical Convolution Multi-View Neural Network)。检测网络增加了三个模块:小卷积非对称模块(Asymmetrical Tiny Convolution Module,ATM)、空洞多视野卷积模块(Dilated Convolution Multi-View Module,DCM)、多尺度特征图融合策略(Fusion strategy of multi-scale feature map,MF)。 ATM学习到的细节特征有助于小尺度违禁品的识别;DCM通过提供局部与全局之间的上下文特征信息来解决遮挡问题;MF则是通过融合高、低层特征图以提高模型在背景干扰情况下违禁品的检测精度。在仿真实验中,采用X光安检领域公开的数据集与自建的数据集,ACMNet在精确度上取得了令人满意的效果。 相似文献
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基于深度学习的语义分割算法可以实现安检违禁品自动识别,并获得违禁品的位置、类别及形状信息。但传统的语义分割算法在面对违禁品尺寸不一且目标多样的识别任务时表现较差。针对该问题,本文提出了一种基于语义分割技术的多目标违禁品识别算法。编码阶段,设计使用空洞空间金字塔卷积模块(Atrous Spatial Pyramid Convolution Block, ASPC),提升网络对于特征图多尺度信息的挖掘能力。同时引入注意力机制,对ASPC模块的特征提取过程进行监督,进一步提升模块的特征提取能力。解码阶段,受U-Net模型启发,采用逐级上采样操作,同时加入1×1卷积实现通道降维,减少计算量,提升模型运行速度。实验结果显示,本文提出的算法在多目标违禁品识别任务中表现良好,平均交并比(mIoU)得分78.62,处理单张图片用时(Time)68ms。 相似文献
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自动化安检技术是维护公共安全、提升安检效率的一项有效措施。在实际场景中很难获得充足的违禁品标注样本用于神经网络的训练,并且在不同场景和安全级别下违禁品的类别也有所不同。为解决基于神经网络的违禁品检测方法所面临的样本不均衡问题,以及避免模型在分割新的违禁品类别时需重新训练的现象,文中提出一种基于图匹配网络的小样本违禁物品分割算法。文中模型将测试图像与参考图像并行输入到图匹配网络中,并根据匹配结果从测试图像中分割出违禁品。所设计的图匹配模块不仅从图间节点的相似性考虑匹配问题,并利用DeepEMD算法建立全局概念,进一步提高测试图和参考图的匹配结果。在SIXray数据集和Xray-PI数据集上的实验表明:本模型在单样本分割任务中得到36.4%和51.2%的类平均交并比,分别比目前先进的单样本分割方法提高2.5%和2.3%。由此表明所设计的算法能有效提升小样本X光图像分割算法的精确度。 相似文献
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RSA Full Domain Hash (RSA-FDH) is a digital signature scheme, secure against chosen message attacks in the random oracle model. The best known security reduction from the RSA assumption is non-tight, i.e., it loses a factor of \(q_s\), where \(q_s\) is the number of signature queries made by the adversary. It was furthermore proven by Coron (Advances in cryptology—EUROCRYPT 2002, Lecture notes in computer science, vol 2332. Springer, Berlin, pp 272–287, 2002) that a security loss of \(q_s\) is optimal and cannot possibly be improved. In this work, we uncover a subtle flaw in Coron’s impossibility result. Concretely, we show that it only holds if the underlying trapdoor permutation is certified. Since it is well known that the RSA trapdoor permutation is (for all practical parameters) not certified, this renders Coron’s impossibility result moot for RSA-FDH. Motivated by this, we revisit the question whether there is a tight security proof for RSA-FDH. Concretely, we give a new tight security reduction from a stronger assumption, the Phi-Hiding assumption introduced by Cachin et al. (Advances in Cryptology—EUROCRYPT’99. Lecture notes in computer science, vol 1592. Springer, Berlin, pp 402–414, 1999). This justifies the choice of smaller parameters in RSA-FDH, as it is commonly used in practice. All of our results (positive and negative) extend to the probabilistic signature scheme PSS (with message recovery). 相似文献
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Wireless local area networks (LANs) are vulnerable to malicious attacks due to their shared medium in unlicensed frequency
spectrum, thus requiring security features for a variety of applications even at the cost of quality of service (QoS). However,
there is very little work on investigating to what extent system performance is affected by security configurations with respect
to mobility scenarios, heterogeneous networks, and different applications. In order to exploit the full potential of existing
security solutions, we present a detailed experimental study to demonstrate the impacts of security features on performance
by integrating cross-layer security protocols in a wireless LAN testbed with IP mobility. We introduce a quality of protection (QoP) model to indicate the benefits of security protocols and then measure the performance cost of security protocols in terms
of authentication time, cryptographic overhead and throughput. Our measurements demonstrate that the effects of security protocols
on QoS parameters span a wide range; for example, authentication time is between 0.11 and 6.28 s, which can potentially affect
packet loss dramatically. We also find that for the same security protocol throughput in non-roaming scenarios can be up to
two times higher than that in roaming scenarios. However, some protocols are robust against mobility with little variation
in system performance; thus, it is possible to provision steady service by choosing security protocols when users’ mobility
pattern is unknown. Furthermore, we provide observations on cross-layer security protocols and suggestions to the design of
future security protocols for real-time services in wireless LANs.
相似文献
Wenye WangEmail: |
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Goldwasser and Micali (J Comput Syst Sci 28(2):270–299, 1984) highlighted the importance of randomizing the plaintext for public-key encryption and introduced the notion of semantic security. They also realized a cryptosystem meeting this security notion under the standard complexity assumption of deciding quadratic residuosity modulo a composite number. The Goldwasser–Micali cryptosystem is simple and elegant but is quite wasteful in bandwidth when encrypting large messages. A number of works followed to address this issue and proposed various modifications. This paper revisits the original Goldwasser–Micali cryptosystem using \(2^k\)-th power residue symbols. The so-obtained cryptosystems appear as a very natural generalization for \(k \ge 2\) (the case \(k=1\) corresponds exactly to the Goldwasser–Micali cryptosystem). Advantageously, they are efficient in both bandwidth and speed; in particular, they allow for fast decryption. Further, the cryptosystems described in this paper inherit the useful features of the original cryptosystem (like its homomorphic property) and are shown to be secure under a similar complexity assumption. As a prominent application, this paper describes an efficient lossy trapdoor function-based thereon. 相似文献
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Restoration in wavelength-routed optical networks by means of ant colony optimization 总被引:1,自引:0,他引:1
Because of the distributed control of the network, the dynamic nature of the traffic and the unpredictability of a failure
event, the flexibility and robustness of ant colony optimization (ACO) make it a suitable candidate for provisioning lightpaths
in an optical network. In this work, we propose a fault-tolerant dynamic routing and wavelength assignment (RWA) algorithm
based on the ACO framework, presenting its integration into the Generalized multi-protocol label switching (GMPLS) control
plane. By simulating two different scenarios, we demonstrate the effectiveness of this algorithm when a single link or node
failure occurs.
相似文献
Helio WaldmanEmail: |