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A Visualization System of Ship Navigation Environment Based on OSG

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A Visualization System of Ship Navigation Environment Based ...

International Conference on Image, Vision and Computing (ICIVC)

作者： Chengcheng Zhang Jianxin Chen Wei Guo Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China

ISBN: (纸本)9781728123264

Maritime safety has become a hot topic over the past few years and ocean supervision is one of the most important parts for the maritime safety administration. Traditional ocean supervision technology usually uses two-dimensional (2D) images information to detect the illegal invasions. However, it is incomplete to represent the complex navigation environment for ships. Fortunately, with the development of virtual reality technology and deep learning, we are able to build a visualization system to establish the virtual 3D ocean scene for ship navigation with obtained information such as image and video in real time. In this paper, we design and implement such a visualization platform, which enables us to establish the 3D scene originated from images in real time, with the use of OSG, 3D modeling and deep learning network.

关键词： Virtual reality OSG 3D modeling Deep learning visualization system three-dimensional displays Ship navigators virtual reality Maritime safety virtual reality technology Time of use images oceans

Long-Distance Entanglement Purification for Quantum communication

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Physical Review Letters 2021年第1期126卷 010503-010503页

作者： Xiao-Min Hu Cen-Xiao Huang Yu-Bo Sheng Lan Zhou Bi-Heng Liu Yu Guo Chao Zhang Wen-Bo Xing Yun-Feng Huang Chuan-Feng Li Guang-Can Guo CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei 230026 People’s Republic of China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 People’s Republic of China Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 People’s Republic of China School of Science Nanjing University of Posts and Telecommunications Nanjing 210003 People’s Republic of China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing 210003 People’s Republic of China

High-quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in tabletop. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled state. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gates, the total purification efficiency can be estimated as 6.6×103 times than the experiment using two pairs of entangled states with spontaneous parametric down-conversion sources. Our results offer the potential to be implemented as part of a full quantum repeater and large-scale quantum network.

关键词： Entanglement manipulation Optical quantum information processing Quantum communication Quantum optics Quantum protocols

Experimental three-state measurement-device-independent quantum key distribution with uncharacterized sources

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arXiv 2020年

作者： Zhou, Xing-Yu Ding, Hua-Jian Zhang, Chun-Hui Li, Jian Zhang, Chun-Mei Wang, Qin Institute of quantum information and technology Nanjing University of Posts and Telecommunications Nanjing210003 China " Broadband Wireless Communication and Sensor Network Technology" Key Lab of Ministry of Education NUPT Nanjing210003 China "Telecommunication and Networks" National Engineering Research Center NUPT Nanjing210003 China

The measurement-device-independent quantum key distribution (MDI-QKD) protocol plays an important role in quantum communications due to its high level of security and practicability. It can be immune to all side-channel attacks directed on the detecting devices. However, the protocol still contains strict requirements during state preparation in most existing MDI-QKD schemes, e.g., perfect state preparation or perfectly characterized sources, which are very hard to realize in practice. In this letter, we investigate uncharacterized MDI-QKD by utilizing a three-state method, greatly reducing the finite-size effect. The only requirement for state preparation is that the state are prepared in a bidimensional Hilbert space. Furthermore, a proof-of-principle demonstration over a 170 km transmission distance is achieved, representing the longest transmission distance under the same security level on record. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum cryptography

280-km experimental demonstration of quantum digital signature with one decoy state

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arXiv 2020年

作者： Ding, Hua-Jian Chen, Jing-Jing Ji, Liang Zhou, Xing-Yu Zhang, Chun-Hui Zhang, Chun-Mei Wang, Qin Institute of quantum information and technology Nanjing University of Posts and Telecommunications Nanjing210003 China "Broadband Wireless Communication and Sensor Network Technology" Key Lab of Ministry of Education NUPT Nanjing210003 China "Telecommunication and Networks" National Engineering Research Center NUPT Nanjing210003 China

Quantum digital signature (QDS) guarantee the unforgeability, nonrepudiation and transferability of signature messages with information-theoretical security, and hence has attracted much attention recently. However, most previous implementations of QDS showed relatively low signature rates or/and short transmission distance. In this paper, we report a proof-of-principle phase-encoding QDS demonstration using only one decoy state. Firstly, such method avoids the modulation of vacuum state, thus reducing experimental complexity and random number consumption. Moreover, incorporating with low-loss asymmetric Mach-Zehnder interferometers and real-time polarization calibration technique, we have successfully achieved higher signature rate, e.g., 0.98 bit/s at 103 km, and to date a record-breaking transmission distance over 280-km installed fibers. Our work represents a significant step towards real-world applications of QDS. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum theory

Universal multi-source domain adaptation

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arXiv 2020年

作者： Yin, Yueming Yang, Zhen Hu, Haifeng Wu, Xiaofu Nanjing University of Posts and Telecommunications Nanjing210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing210003 China National Engineering Research Center of Communications and Networking Nanjing University of Posts and Telecommunications Nanjing210003 China

Unsupervised domain adaptation enables intelligent models to transfer knowledge from a labeled source domain to a similar but unlabeled target domain. Recent study reveals that knowledge can be transferred from one source domain to another unknown target domain, called Universal Domain Adaptation (UDA). However, in the real-world application, there are often more than one source domain to be exploited for domain adaptation. In this paper, we formally propose a more general domain adaptation setting, universal multi-source domain adaptation (UMDA), where the label sets of multiple source domains can be different and the label set of target domain is completely unknown. The main challenges in UMDA are to identify the common label set between each source domain and target domain, and to keep the model scalable as the number of source domains increases. To address these challenges, we propose a universal multi-source adaptation network (UMAN) to solve the domain adaptation problem without increasing the complexity of the model in various UMDA settings. In UMAN, we estimate the reliability of each known class in the common label set via the prediction margin, which helps adversarial training to better align the distributions of multiple source domains and target domain in the common label set. Moreover, the theoretical guarantee for UMAN is also provided. Massive experimental results show that existing UDA and multi-source DA (MDA) methods cannot be directly applied to UMDA and the proposed UMAN achieves the state-of-the-art performance in various UMDA settings. Copyright © 2020, The Authors. All rights reserved.

关键词： Machine learning

Measurement-device-independent quantum key distribution of multiple degrees of freedom of a single photon

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arXiv 2020年

作者： Yan, Yu-Fei Zhou, Lan Zhong, Wei Sheng, Yu-Bo Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 China Schoool of Science Nanjing University of Posts and Telecommunications Nanjing210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 China

Measurement-device-independent quantum key distribution (MDI-QKD) provides us a powerful approach to resist all attacks at detection side. Besides the unconditional security, people also seek for high key generation rate, but MDI-QKD has relatively low key generation rate. In this paper, we provide an efficient approach to increase the key generation rate of MDI-QKD by adopting multiple degrees of freedom (DOFs) of single photons to generate keys. Compared with other high-dimension MDI-QKD protocols encoding in one DOF, our protocol is more flexible, for our protocol generating keys in independent subsystems and the detection failure or error in a DOF not affecting the information encoding in other DOFs. Based on above features, our MDI-QKD protocol may have potential application in future quantum communication field. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum cryptography

Long-distance entanglement purification for quantum communication

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arXiv 2021年

作者： Hu, Xiao-Min Huang, Cen-Xiao Sheng, Yu-Bo Zhou, Lan Liu, Bi-Heng Guo, Yu Zhang, Chao Xing, Wen-Bo Huang, Yun-Feng Li, Chuan-Feng Guo, Guang-Can CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 China College of Mathematics & Physics Nanjing University of Posts and Telecommunications Nanjing210003 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 China

High quality long-distance entanglement is essential for both quantum communication and scalable quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in table-top. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled state. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt (CHSH) inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gate, the total purification efficiency can be estimated as 6.6 × 103 times than the experiment using two pairs of entangled states with spontaneous parametric down conversion (SPDC) sources. Our results offer the potential to be implemented as part of a full quantum repeater and large scale quantum network. Copyright © 2021, The Authors. All rights reserved.

关键词： Quantum communication

Improving the Performance of Practical Decoy-State Measurement-Device-Independent Quantum key Distribution with Biased Basis Choice

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communications in Theoretical Physics 2018年第9期69卷 331-336页

作者： Chun-Hui Zhang Chun-Mei Zhang Qin Wang Institute of Signal Processing Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network TechnologyNanjing University of Posts and TelecommunicationsMinistry of EducationNanjing 210003China

Statistical fluctuations are unavoidable in realistic quantum key distribution (QKD) due to finite-size effect. Based on the four-intensity proposal on measurement-device-independent QKD (MDI-QKD) in [Phys. Rev. A93 (2016) 042324], we particularly analyze the scenario that only three intensities are used, namely a three-intensity decoy-state MDI-QKD with biased basis choice. After performing full parameter optimization method, simulations results demonstrate that this scenario can obtain distinct enhancement compared with the conventional unbiased threeintensity decoy-state method, e.g. Xu et al.’s [Phys. Rev. A 89 (2014) 052333]. Furthermore, results also show that it works more efficiently by using HSPS than using WCS at longer transmission distance.

关键词： measurement-device-independent quantum key distribution statistical fluctuations biased basis choice

Average Channel Capacity Analysis for Visible Light communications with Random Receivers

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Average Channel Capacity Analysis for Visible Light Communic...

International Conference on wireless communications and Signal Processing (WCSP)

作者： Xian-Tao Fu Rong-Rong Lu Sheng-Hong Lin Jin-Yuan Wang Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China Shanghai Key Laboratory of Trustworthy Computing East China Normal University Shanghai China Key Laboratory of Opto-technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University Lanzhou China National Local Joint Engineering Research Center for Communication and Network Technologies Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (数字)9781728172361

ISBN: (纸本)9781728172378

For indoor visible light communications (VLC), the receivers are usually set to be fixed ones in previous studies. However, the locations and orientations of receivers are affected by random factors in practical VLC systems. In this paper, the performance of VLC with random receivers is investigated. We consider an VLC system, which consists of a transmitter and a receiver. The main noise is additive white Gaussian noise. Two random factors (i.e., random location and random orientation) of the receiver are considered. Based on the established system model, closed-form expressions of the average channel capacity for systems with random location and random orientation are derived, respectively. Numerical results verify the accuracy of the derived theoretical expressions. Moreover, the impacts of the nominal optical intensity, the dimming target, the transmitter height and the Lambertian emission order on system performance are also discussed.

关键词： Visible light communication Optical transmitters Optical receivers Light emitting diodes Channel capacity High-speed optical techniques wireless communication