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Advanced geometry surface coding for dynamic point cloud compression

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arXiv 2021年

作者： Xiong, Jian Gao, Hao Wang, Miaohui Li, Hongliang Ngan, King Ngi Lin, Weisi College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Nanjing210003 China College of Artificial Intelligence Nanjing University of Posts and Telecommunications Nanjing210003 China School of Computer Science and Cyberspace Security Hainan University China Guangdong Key Laboratory of Intelligent Information Processing Shenzhen University China School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu611731 China School of Computer Science and Engineering Nanyang Technological University Singapore639798 Singapore

In video-based dynamic point cloud compression (V-PCC), 3D point clouds are projected onto 2D images for compressing with the existing video codecs. However, the existing video codecs are originally designed for natural visual signals, and it fails to account for the characteristics of point clouds. Thus, there are still problems in the compression of geometry information generated from the point clouds. Firstly, the distortion model in the existing rate-distortion optimization (RDO) is not consistent with the geometry quality assessment metrics. Secondly, the prediction methods in video codecs fail to account for the fact that the highest depth values of a far layer is greater than or equal to the corresponding lowest depth values of a near layer. This paper proposes an advanced geometry surface coding (AGSC) method for dynamic point clouds (DPC) compression. The proposed method consists of two modules, including an error projection model-based (EPM-based) RDO and an occupancy map-based (OM-based) merge prediction. Firstly, the EPM model is proposed to describe the relationship between the distortion model in the existing video codec and the geometry quality metric. Secondly, the EPM-based RDO method is presented to project the existing distortion model on the plane normal and is simplified to estimate the average normal vectors of coding units (CUs). Finally, we propose the OM-based merge prediction approach, in which the prediction pixels of merge modes are refined based on the occupancy map. Experiments tested on the standard point clouds show that the proposed method achieves an average 9.84% bitrate saving for geometry compression. Copyright © 2021, The Authors. All rights reserved.

关键词： Signal distortion

A Analysis of Attack and Defense Mobile Ad Hoc Network Based on OPNET

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A Analysis of Attack and Defense Mobile Ad Hoc Network Based...

作者： Jiahao Dai Xiaofeng Xu Science and Technology on Communication Information Security Control Laboratory China Electronic Group Corporation No.36 Institute

Due to the broadcast nature of wireless communications, the damage to mobile ad hoc networks is becoming more and more common. We propose a network stability model that can effectively reflect the network performance when the network is damaged in real time. The Ad Hoc network model is built by using the node model supporting the IEEE802.11 standard provided by OPNET software to simulate the network performance of the network under different degrees of damage. This model provides an effective way for the simulation analysis of network performance under the condition of Ad Hoc network damage.

关键词： OPNET Ad Hoc networks stability network defense

On the regularization and optimization in quantum detector tomography

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arXiv 2022年

作者： Xiao, Shuixin Wang, Yuanlong Zhang, Jun Dong, Daoyi Yokoyama, Shota Petersen, Ian R. Yonezawa, Hidehiro University of Michigan Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong University Shanghai200240 China School of Engineering and Information Technology University of New South Wales CanberraACT2600 Australia Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China Centre for Quantum Computation and Communication Technology Australian Research Council Centre for Quantum Dynamics Griffith University BrisbaneQLD4111 Australia Centre for Quantum Computation and Communication Technology Australian Research Council CanberraACT2600 Australia School of Engineering Australian National University CanberraACT2601 Australia

Quantum detector tomography (QDT) is a fundamental technique for calibrating quantum devices and performing quantum engineering tasks. In this paper, we utilize regularization to improve the QDT accuracy whenever the probe states are informationally complete or informationally incomplete. In the informationally complete scenario, without regularization, we optimize the resource (probe state) distribution by converting it to a semidefinite programming problem. Then in both the informationally complete and informationally incomplete scenarios, we discuss different regularization forms and prove the mean squared error scales as O(1/N) or tends to a constant with N state copies under the static assumption. We also characterize the ideal best regularization for the identifiable parameters, accounting for both the informationally complete and informationally incomplete scenarios. Numerical examples demonstrate the effectiveness of different regularization forms and a quantum optical experiment test shows that a suitable regularization form can reach a reduced mean squared error. Copyright © 2022, The Authors. All rights reserved.

关键词： Tomography

A Novel Localization Method Based on FDA Beam Intersection

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A Novel Localization Method Based on FDA Beam Intersection

International Conference on Computer and communications (ICCC)

作者： Yezi Ma Ping Wei Huaguo Zhang School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China Science and Technology on Communication Information Security Control Laboratory School of Information and Communication Engineering University of Electronic Science and Technology of China Chengdu China

ISBN: (数字)9781728147437

ISBN: (纸本)9781728147444

In the past localization methods, both mechanical and phased array radars require angle scanning because their beampatterns are only angle-dependent, resulting in the echo time difference only contains the range information of the target. It will cause some ambiguity problems and limitations. Since Frequency Diverse Array (FDA) was proposed, its range-angle dependent beampattern provided more degrees of freedom (DoFs) to obtain more information in array signal processing. However, how to use these increased DoFs to get more information still needs to be studied. In this paper, we propose a novel localization method using FDA beam intersection. In this proposed method, part of the FDA beampattern approximates a straight line and propagates throughout the range axis. This moving beam line can capture the target like a fast-moving net and the echo time difference contains both the angle and range information of the target. By a simple straight-line intersection, we can obtain the whole position information, where two FDA beam lines intersect at the target. A simulation diagram is provided to illustrate the proposed localization process.

关键词： Radar Array signal processing Frequency diversity Radar antennas Phased arrays Mathematical model Receivers

Twin-field quantum key distribution with passive-decoy state

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arXiv 2020年

作者： Teng, Jun Lu, Feng-Yu Yin, Zhen-Qiang Fan-Yuan, Guan-Jie Wang, Rong Wang, Shuang Chen, Wei Huang, Wei Xu, Bing-Jie Guo, Guang-Can Han, Zheng-Fu CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China HefeiAnhui230026 China State Key Laboratory of Cryptography P. O. Box 5159 Beijing100878 China Science and Technology on Communication Security Laboratory Institute of Southwestern Communication ChengduSichuan610041 China

Twin-Field quantum key distribution (TF-QKD) and its variants, e.g. Phase-Matching QKD, Sending-or-not-sending QKD, and No Phase Post-Selection TFQKD promise high key rates at long distance to beat the rate distance limit without a repeater. The security proof of these protocols are based on decoy-state method, which is usually performed by actively modulating a variable optical attenuator together with a random number generator in practical experiments, however, active-decoy schemes like this may lead to side channel and could open a security loophole. To enhance the source security of TF-QKD, in this paper, we propose passive-decoy based TF-QKD, in which we combine TF-QKD with the passive-decoy method. And we present a simulation comparing the key generation rate with that in active-decoy, the result shows our scheme performs as good as active decoy TF-QKD, and our scheme could reach satisfactory secret key rates with just a few photon detectors. This shows our work is meaningful in practice. © 2020, CC-BY.

关键词： Random number generation

Finite-key analysis for twin-field quantum key distribution based on generalized operator dominance condition

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arXiv 2020年

作者： Wang, Rui-Qiang Yin, Zhen-Qiang Lu, Feng-Yu Wang, Rong Wang, Shuang Chen, Wei Huang, Wei Xu, Bing-Jie Guo, Guang-Can Han, Zheng-Fu CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Synergetic Innovation Center of Quantum Information & Quantum Physics University of Science and Technology of China HefeiAnhui230026 China State Key Laboratory of Cryptography P. O. Box 5159 Beijing100878 China Science and Technology on Communication Security Laboratory Institute of Southwestern Communication ChengduSichuan610041 China

Quantum key distribution (QKD) can help two distant peers to share secret key bits, whose security is guaranteed by the law of physics. In practice, the secret key rate of a QKD protocol is always lowered with the increasing of channel distance, which severely limits the applications of QKD. Recently, twin-field (TF) QKD has been proposed and intensively studied, since it can beat the rate-distance limit and greatly increase the achievable distance of QKD. Remarkalebly, K. Maeda et. al. proposed a simple finite-key analysis for TF-QKD based on operator dominance condition. Although they showed that their method is sufficient to beat the rate-distance limit, their operator dominance condition is not general, i.e. it can be only applied in three decoy states scenarios, which implies that its key rate cannot be increased by introducing more decoy states, and also cannot reach the asymptotic bound even in case of preparing infinite decoy states and optical pulses. Here, to bridge this gap, we propose an improved finite-key analysis of TF-QKD through devising new operator dominance condition. We show that by adding the number of decoy states, the secret key rate can be furtherly improved and approach the asymptotic bound. Our theory can be directly used in TF-QKD experiment to obtain higher secret key rate. Our results can be directly used in experiments to obtain higher key rates. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum cryptography

Topologically Enhanced Circular Dichroism from Metasurfaces

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Physical Review Applied 2021年第3期16卷 L031001-L031001页

作者： Jiaxin Chen Lishuan Wang Wei Wu Wei Cai Huasong Liu Mengxin Ren Jingjun Xu Key Laboratory of Weak-Light Nonlinear Photonics Ministry of Education School of Physics and TEDA Applied Physics Institute Nankai University Tianjin 300071 People’s Republic of China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300308 People’s Republic of China Tianjin Key Laboratory of Optical Thin Film Tianjin Jinhang Technical Physics Institute Tianjin 300080 People’s Republic of China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan Shanxi 030006 People’s Republic of China

Circular dichroism (CD) is one of the most distinctive properties of chiral materials. In recent decades, chiral metasurfaces have been regarded as a promising framework to realize chiral optical devices with ultrathin thickness and compact footprints. Various efforts have been devoted to increase the CD response from such metasurfaces. Here we present a method to enhance the CD effect from metasurfaces utilizing a topological concept. Two multilayered photonic crystals with different topological invariants are adopted and put in contact leading to the appearance of a topological edge state and a distinct electromagnetic field concentration at the interface. By embedding L-shaped chiral metasurfaces into the interface, the CD response is observed to be obviously boosted. We find that due to the robustness feature of the topological edge state, the spectral position of the CD peak is fixed at the edge-state wavelength and is immune to structural variation of the metasurface array. Considering that the multilayered films are easy to fabricate, such a topological concept could act as a simple and feasible strategy for enhancing chiral optical response from nanoscales, and could find wide applications in realizing ultracompact polarization-selective optical components.

关键词： Edge states Metamaterials Optical & microwave phenomena Photonics Topological effects in photonic systems Devices

An Integration Testing Framework and Evaluation Metric for Vulnerability Mining Methods

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China communications 2018年第2期15卷 190-208页

作者： Jin Li Jinfu Chen Minhuan Huang Minmin Zhou Wanggen Xie Zhifeng Zeng Shujie Chen Zufa Zhang National key laboratory of science and technology on information system security Beijing institute of system engineering School of Computer Science and Communication Engineering Jiangsu University

Software an important way to vulnerability mining is detect whether there are some loopholes existing in the software, and also is an important way to ensure the secu- rity of information systems. With the rapid development of information technology and software industry, most of the software has not been rigorously tested before being put in use, so that the hidden vulnerabilities in software will be exploited by the attackers. Therefore, it is of great significance for us to actively de- tect the software vulnerabilities in the security maintenance of information systems. In this paper, we firstly studied some of the common- ly used vulnerability detection methods and detection tools, and analyzed the advantages and disadvantages of each method in different scenarios. Secondly, we designed a set of eval- uation criteria for different mining methods in the loopholes evaluation. Thirdly, we also proposed and designed an integration testing framework, on which we can test the typical static analysis methods and dynamic mining methods as well as make the comparison, so that we can obtain an intuitive comparative analysis for the experimental results. Final- ly, we reported the experimental analysis to verify the feasibility and effectiveness of the proposed evaluation method and the testingframework, with the results showing that the final test results will serve as a form of guid- ance to aid the selection of the most appropri- ate and effective method or tools in vulnera- bility detection activity.

关键词： software vulnerability detection loopholes information security evaluationmethod testing framework

MILP-aided bit-based division property for ARX ciphers

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science China(information sciences) 2018年第11期61卷 229-231页

作者： Ling SUN Wei WANG Ru LIU Meiqin WANG Key Laboratory of Cryptologic Technology and Information Security Ministry of EducationShandong University Science and Technology on Communication Security Laboratory No.30 Research Institute of China Electronics Technology Group Corporation State Key Laboratory of Cryptology

Division property, which was proposed by Todo [1]at EUROCRYPT 2015, is a new technique to detect integral property. It could explicitly depict the hidden properties between the traditional ALL and BALANCE properties in integral cryptanalysis [2], which made it an effective method to search integral distinguishers. The definition is given as follows.

关键词： MILP-aided bit-based division property for ARX ciphers ARX