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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

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

arXiv

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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

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Resource Allocation for Outage Probability Minimization in Cognitive wireless Powered communication networks

Resource Allocation for Outage Probability Minimization in C...

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International Conference on communication technology (ICCT)

作者： Qun Li Ding Xu Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China

This paper considers a cognitive wireless powered communication network (CWPCN) consisting of a cognitive base station (CBS) and a set of secondary users (SUs) sharing spectrum with a primary user (PU). The transmission time is assumed to be divided into two parts, where the CBS transfers energy in the downlink during the first time part, and the SUs use the harvested energy to transmit in the uplink based on the time-division multiple access (TDMA) during the second time part. We investigate the problem for minimizing the average outage probability of the SUs by jointly optimizing the time allocation and the downlink transmit power allocation under the interference power and the transmit power constraints and propose a heuristic algorithm to solve it. Simulations show that the proposed algorithm greatly outperforms the benchmark algorithms.

关键词： Resource management wireless communication Interference Power system reliability Probability wireless sensor networks Downlink

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QoE Optimization for Traffic Offloading from LTE to WiFi

QoE Optimization for Traffic Offloading from LTE to WiFi

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IEEE Global Conference on Consumer Electronics (GCCE)

作者： Feng Tian Yue Yu Dapeng Li Jingwu Cui Yue Dong Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China

ISBN: (数字)9781728135755

ISBN: (纸本)9781728135762

In this paper, a novel QoE (Quality of Experience) optimization mechanism is proposed for the coexistence between LTE and WiFi networks, where traffic offloading is enabled from LTE to WiFi. Firstly, the throughput models of LTE and WiFi are analyzed, respectively. And then the users' satisfaction function is introduced to measure QoE. An optimal problem that maximizing the QoE of LTE network with guaranteeing the QoE of WiFi network, is formulated and solved by transformation and simplification. Simulation results indicate that traffic offloading can greatly improve the QoE of LTE network.

关键词： wireless fidelity Long Term Evolution Quality of experience Optimization Throughput wireless communication Interference

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Moving Object Distance Estimation Method Based on Target Extraction with a Stereo Camera

Moving Object Distance Estimation Method Based on Target Ext...

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International Conference on Image, Vision and Computing (ICIVC)

作者： Jingyi Zhang Jianxin Chen Qingyu Lin Liming Cheng 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

Real-time distance estimation with high accuracy is crucial to robot applications such as navigation and obstacle negotiation. However, considering the truth that high accuracy brings huge computation, the previous work either accelerates the distance estimation process through hardware, or only estimates the static objects, or sacrifices accuracy to realize real-time. In order to improve the trade-off between speed and accuracy, in this paper we propose a stereovision-based method that integrates the object detection and tracking into stereo matching. We utilize kernelized correlation filter (KCF) to track the moving object, and then extract target regions from image pair as input images to compute disparity map. In addition, we update each pixel's disparity by a simple but effective approach to further refine disparity map. Eventually, distance is calculated with disparity by triangulation. Experimental results show that our proposed method is suitable for dynamic environment, the extraction method improves the speed of the entire system, and the average accuracy of distance estimation can achieve over 95% from 88 cm to 300 cm when baseline is 151 mm.

关键词： Distance estimation Stereo vision KCF tracking Target region extraction Disparity refinement Triangulation Stereo cameras triangulation Stereoviews extraction of object Object detection object distance Static objects

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Geometry Based LM of Robot to Imitate Human Motion with Kinect

Geometry Based LM of Robot to Imitate Human Motion with Kine...

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International Conference on Image, Vision and Computing (ICIVC)

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

ISBN: (纸本)9781728123264

Humanoid robots are easily accepted by people because they have a body shape and appearance close to human. Humanoid robots have many application scenarios and great application potentials. Nevertheless, it is not easy to realize robot simulation due to the different physical structures of human bodies and robots. In this paper, we propose a geometry based LM algorithm for the robot to imitate the human motion of upper limb in real time. This method greatly improves the joint angle similarity under the premise of ensuring the similarity of the end trajectories. We designed a comprehensive and unrestricted motion simulation experiment to verify this method.

关键词： Kinect Inverse kinematic Nao Levenberg-Marquardt Geometry game player geometry Robot Human motion Humanoid robots Human Body

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A Reliable Hand Tracking Method Using Kinect

A Reliable Hand Tracking Method Using Kinect

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International Conference on Image, Vision and Computing (ICIVC)

作者： Qinyu Lin Jianxin Chen Jiangyi Zhang Ling Yao Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781728123264

Hand tracking has been focused over years in the field of human-computer interaction. But there are still some challenges such as reliability and accuracy due to the highly articulated and deformable of hand. In this paper we propose a real time hand tracking method with the depth information of the Kinect sensor. In this method, we preprocessed the depth information with a pixel filter to deal with the noise. Then we isolated the hand region from the depth image by using the KCF (Kernelized Correlation Filters) to the confined minimum depth area, which can release the limitation of hand movement range. Then the forearm region is segmented with assistance of PCA (Principle Component Analysis). And, to accurately locate the fingertip position, we integrate the maximum geodesic distance to hand centroid into EIC (Extended Inscribed Circle). And by labelling each finger to avoid mistaken fingertip determination. Experimental results verify the accuracy and reliability of our solution.

关键词： Real-time systems Human computer interaction Tracking Covariance matrices Principal component analysis Wrist Reliability

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Ternary Weighted networks with Equal Quantization Levels

Ternary Weighted Networks with Equal Quantization Levels

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Asia-Pacific Conference on communications

作者： Yuanyuan Chang Xiaofu Wu Suofei Zhang Jun Yan Key Lab of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (数字)9781728136790

ISBN: (纸本)9781728136806

Recent progress in deep convolutional neural networks has considerably changed the landscape of speech recognition, computer vision, natural language processing and so on. However, limited by the large number of parameters, the memory space and high computational complexity, it is a challenging task to deploy the deep neural network model in embedded system. To solve this problem, we propose Equal Trained Ternary Quantization (ETTQ), a ternary quantization method by improving Trained Ternary Quantization, which uses only a full-precision scaling coefficient for each layer, and quantize the weights to three levels. These positive and negative weights have same absolute values that are trainable parameters. Experiments show that the performance of ETTQ is only slightly worse than TTQ, but can converge faster and more stable during the training over CIFAR-10 and CIFAR-100 datasets.

关键词： Quantization (signal) Neural networks Training Computational modeling Solid modeling Computer vision Backpropagation

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Face Recognition Based on Two-stage CNN Combined with Transfer Learning

Face Recognition Based on Two-stage CNN Combined with Transf...

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International Conference on Image, Vision and Computing (ICIVC)

作者： Anqi Zhou Jianxin Chen Jie Ding Zhaolai Pan 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

In recent years, pattern recognition has received wide attention, especially face recognition. Research shows that traditional methods have limits in face recognition under unrestricted environment because of illumination, facial expression, pose and so on. Deep learning is chosen to solve these problems. In this paper, we propose a complete method for face recognition under unrestricted environment by deep learning. First, we design a novel two-stage convolutional neural network for face detection and alignment. The first stage of the network aims at searching face windows and their bounding box regression vector. The second stage merges facial candidates which are covered highly. Then, the network finishes the task of face detection and alignment whose outputs are face regions and the position of the five facial landmarks. It achieves great performance on angle of faces in image and obtains accuracy of 96.1% on AFW and 98.9% on FDDB. Then faces are sent to convolutional neural network for transfer learning because of limited training samples. On the testing dataset, the accuracy of face recognition reaches to 95.3%, comparing with 89.1% of the original network. What' more, our method is better than the traditional algorithms and general CNN.

关键词： Face detection Face recognition Deep learning Transfer learning Facial Recognition Transfer (Psychology) AUXILIARY FEEDWATER

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3D Modeling of the Rotationally Symmetric Objects Using Kinect

3D Modeling of the Rotationally Symmetric Objects Using Kine...

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International Conference on Image, Vision and Computing (ICIVC)

作者： Jie Ding Jianxin Chen Anqi Zhou Zhimin Chen 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

With the appearance of RGB-D cameras, 3D reconstruction becomes convenient. Previous studies focused on the objects with strong structural features. But for the objects with weak structure, such as rotationally symmetric objects. There is no solution. In this paper, we propose a method to model the rotationally symmetric objects. In this method, we scan the object in one view and the point cloud is projected to the 2D space. Then, we extract the boundary of the point cloud. And the Least Square is adopted to fit the extracted boundary to improve the accuracy of the boundary. At last, we rotate the fitting boundary and get the model. To verify the effectiveness of our method, several experiments have been performed to evaluate the error of the models. In addition, we use it to reconstruct the object with the hole on one side. And the results show the efficiency and computational complexity of our method.

关键词： Three-dimensional displays Fitting Computational modeling Solid modeling Mathematical model Strain Cameras

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