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Study on the Segmentation Method of Multi-Phase CT Liver Tumor Based on Dual Channel U-Nets

Journal of Physics: Conference Series 2021年第1期1828卷

作者： Changchang Xu Dong Hu YaoDong Zhang Yuwei Pang Jiangsu Province's Key Lab of Image Procession and Image Communications Nanjing University of Posts and Telecommunications Nanjing 210003 China Education Ministry's Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Education Ministry's Engineering Research Center of Ubiquitous Network and Heath Service Nanjing University of Posts and Telecommunications Nanjing 210003 China The first clinical medical college of Nanjing Medical University Nanjing University of Posts and Telecommunications Nanjing 210003 China

As a common malignant tumor disease, hepatocellular carcinoma is the most common cancers in the world. The incidence of hepatocellular carcinoma in China is higher than that in the world. Therefore, it is very important for doctors to separate liver and tumor from CT images by means of computer-aided diagnosis and treatment. In this paper, a multiscale DC-CUNets network liver tumor segmentation method is proposed to enhance the fusion of multi-phase image features in CT, the scale of liver tumors, and the optimization of network training process. (1) A multistage CT liver tumor segmentation method based on two-channel cascaded U-Nets (DC-CUNets) is proposed. The liver was segmented using the first-order U-Net, and then the segmented area of interest of the liver was input into the second-order U-Net network to segment liver tumors. We designed two-channel U-Nets to learn the image characteristics of CT images in arterial and venous phases respectively, and to achieve two-channel feature fusion through feature cascade to improve the overall accuracy of liver tumor segmentation.(2) A multistage CT liver tumor segmentation method based on multiscale DC-CUNets was proposed. For the scale problem of liver tumors, we designed a two-layer multiscale void convolution module to obtain image features at different scales for large, medium and small tumors, and fuse the multiscale features at the output of the module. We have replaced the convolution layer of the fourth module in the second-order two-channel liver tumor segmentation U-Nets by the two-layer multiscale cavity convolution module to implement multiscale DC-CUNets.

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On the secrecy performance of Random VLC networks with imperfect CSI and protected zone

arXiv

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arXiv 2019年

作者： Wang, Jin-Yuan Qiu, Yu Lin, Sheng-Hong Wang, Jun-Bo Lin, Min Liu, Cheng Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Vertical Industry Development Department Baidu China Co. Ltd. Shanghai201210 China

This paper investigates the physical-layer security for a random indoor visible light communication (VLC) network with imperfect channel state information (CSI) and a protected zone. The VLC network consists of three nodes, i.e., a transmitter (Alice), a legitimate receiver (Bob), and an eavesdropper (Eve). Alice is fixed in the center of the ceiling, and the emitted signal at Alice satisfies the non-negativity and the dimmable average optical intensity constraint. Bob and Eve are randomly deployed on the receiver plane. By employing the protected zone and considering the imperfect CSI, the stochastic characteristics of the channel gains for both the main and the eavesdropping channels is first analyzed. After that, the closed-form expressions of the average secrecy capacity and the lower bound of secrecy outage probability are derived, respectively. Finally, Monte-Carlo simulations are provided to verify the accuracy of the derived theoretical expressions. Moreover, the impacts of the nominal optical intensity, the dimming target, the protected zone and the imperfect CSI on secrecy performance are discussed, respectively. Copyright © 2019, The Authors. All rights reserved.

关键词： Visible light communication

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A network Adaptive Fragmentation Algorithm for P2P-Based CDN 9

A Network Adaptive Fragmentation Algorithm for P2P-Based CDN

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2017 9th IEEE International Conference on communication Software and networks (ICCSN 2017)

作者： Yunyi Zheng Jianxin Chen Yi Cheng Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications

ISBN: (纸本)9781509038237;9781509038220

P2 P-based content request has been widely used because of its numerous advantages, such as flexibility, load distribution, efficiency and so on. However, there are still some problems to be solved such as service stability, adaptation and so on. The fragmentation methods used in existing P2 P systems are generally fixed block-size method or fixed duration method,which have significantly different performances in different network conditions and cannot adjust to the change of network conditions. In this paper, a novel method is presented to provide adaptive adjustment of fragmentation size for enhancing the performance and service stability. To calculate the adaptive size of fragmentation, several factors are taken into consideration including transmission rate, packet loss rate, file distributions and different peers. The simulation results show that the presented method performs better than the other methods in most network conditions.

关键词： P2P fragmentation adaptive fixed block size fixed duration transmission rate packet loss rate file distributions different peers

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Robust and Passive Motion Detection with COTS WiFi Devices

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Tsinghua Science and technology 2017年第4期22卷 345-359页

作者： Hai Zhu Fu Xiao Lijuan Sun Xiaohui Xie Panlong Yang Ruchuan Wang the College of Computer Nanjing University of Posts and Telecommunications the Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education and College of Computer Nanjing University of Posts and Telecommunications the College of Computer Science and Technology University of Science and Technology of China

Device-free Passive（DfP） detection has received increasing attention for its ability to support various pervasive applications. Instead of relying on variable Received Signal Strength（RSS）, most recent studies rely on finer-grained Channel State Information（CSI）. However, existing methods have some limitations, in that they are effective only in the Line-Of-Sight（LOS） or for more than one moving individual. In this paper, we analyze the human motion effect on CSI and propose a novel scheme for Robust Passive Motion Detection（R-PMD）. Since traditional low-pass filtering has a number of limitations with respect to data denoising, we adopt a novel Principal Component Analysis（PCA）-based filtering technique to capture the representative signals of human motion and extract the variance profile as the sensitive metric for human detection. In addition, existing schemes simply aggregate CSI values over all the antennas in MIMO systems. Instead, we investigate the sensing quality of each antenna and aggregate the best combination of antennas to achieve more accurate and robust detection. The R-PMD prototype uses off-the-shelf WiFi devices and the experimental results demonstrate that R-PMD achieves an average detection rate of 96.33% with a false alarm rate of 3.67%.

关键词： device-free passive detection Received Signal Strength（RSS） channel state information MIMO

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Influence of oceanic turbulence on propagation of Airy vortex beam carrying orbital angular momentum

arXiv

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arXiv 2018年

作者： Wang, Xinguang Yang, Zhen Zhao, Shengmei Nanjing210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education NUPT Nanjing210003 China

With Rytov approximation theory, we derive the analytic expression of de- tection probability of Airy vortex beam carrying orbital angular momentum (OAM) through an anisotropic weak oceanic turbulence. We investigate the influences of turbulence parameters and beam parameters on the propagation properties of Airy-OAM beam. The numerical simulation results show that the anisotropic oceanic turbulence with a lower dissipation rate of temperature vari- ance, smaller ratio of temperature and salinity contributions to the refractive index spectrum, higher dissipation rate of kinetic energy per unit mass of fluid, bigger inner scale factor, larger anisotropic coefficient causes the larger detection probability of Airy-OAM beam. Moreover, the Airy-OAM beam with a smaller topological charge, larger main ring radius and longer wavelength, has strong resistance to oceanic turbulent interference. Additionally, the detection proba- bility decreases with the increase of receiving aperture size. In comparison with Laguerre-Gaussian-OAM beam, Airy-OAM beam has more anti-interference to turbulence when its topological charge is larger than 5 due to its non-diffraction and self-healing characteristics. The results are useful for underwater optical communication link using Airy-OAM beam. Copyright © 2018, The Authors. All rights reserved.

关键词： Anisotropy

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Experimental verification of steerability via geometric Bell-like inequalities

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Physical Review A 2018年第3期97卷 032107-032107页

作者： Jian Li Cen-Yang Wang Tong-Jun Liu Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing 210003 China

Quantum steering is one form of quantum correlations interpolating between entanglement and Bell nonlocality, which in some cases can be detected by various steering inequalities. Recently, a remarkable and useful steerability criterion via geometric Bell-like inequalities was established [M. Zukowski, A. Dutta, and Z. Yin, Phys. Rev. A 91, 032107 (2015)]. We report an experimental investigation of this steering criterion and verify the geometric Bell-like steering inequality experimentally by using of the Werner states. The results demonstrate that the geometric Bell-like steering inequality is a convenient tool to detect quantum steering both theoretically and practically.

关键词： Quantum correlations in quantum information

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Modulating the Lasing Performance of the Quantum Dot-Cavity System by Adding a Resonant Driving Field

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Chinese Physics Letters 2017年第1期34卷 115-119页

作者：秦利国王琴 Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003 Key Lab of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003

We propose a new scheme on modulating the lasing performance of a quantum dot-cavity system. Compared to the conventional above-band pump, in our new scheme an additional resonant driving field is applied on the quantum dot-cavity system. By employing the master equation theory and the Jaynes-Cummings model, we are able to study the interesting phenomenon of the coupling system. To compare the different behaviors between using our new scheme and the conventional method,we carry out investigatioin for both the 'good system'and 'more realistic system', characterizing several important parameters, such as the cavity population, exciton population and the second-order correlation function at zero time delay. Through numerical simulations,we demonstrate that for both the good system and more realistic system, their lasing regimes can be displaced into other regimes in the presence of a resonant driving field.

关键词： Modulating the Lasing Performance of the Quantum Dot-Cavity System by Adding a Resonant Driving Field

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Three-step three-party quantum secure direct communication

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中国科学（物理学力学天文学） 2018年第9期61卷 26-30页

作者： Shan-Shan Chen Lan Zhou Wei Zhong Yu-Bo Sheng Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China College of Mathematics & Physics Nanjing University of Posts and Telecommunications Nanjing 210003 China Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsMinistry of Education Nanjing 210003 China

We propose a three-party quantum secure direct communication (QSDC) protocol with hyperentanglement in both spatial-mode and polarization degrees of *** secret message can be encoded independently with desired unitary operations in two degrees of *** this protocol,a party can synchronously obtain the other two parties' *** with previous three-party QSDC protocols,our protocol has several ***,the single photons in our protocol are only required to transmit for three *** advantage makes this protocol simple and ***,Alice and Bob can send different secret messages to Charlie,***,with hyperentanglement,this protocol has a higher information capacity than other protocols.

关键词： quantum communication quantum secure direct communication hyperentanglement

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Power allocation optimization in MC-NOMA systems for maximizing weighted sum-rate 24

Power allocation optimization in MC-NOMA systems for maximiz...

引用

24th Asia-Pacific Conference on communications, APCC 2018

作者： Chen, Ruilu Wang, Xiaoming Xu, Youyun School of Telecommunication and Information Engineering Nanjing Univ. of Posts and Telecom. Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing Univ. of Posts and Telecom. Nanjing China National Engineering Research Center of Comm. and Network Nanjing Univ. of Posts and Telecom. Nanjing China

ISBN: (纸本)9781538669280

In this paper, we investigate a power allocation scheme in downlink multi-carrier non-orthogonal multiple access (MC-NOMA) systems for maximizing weighted sum-rate. Taking user-priority into account, we add the weighting factors into the formulated optimization problem. Firstly, we give sufficient and necessary concavity conditions that should be satisfied by the proposed weighted sum-rate maximization problem. Then, for more generally non-concave case, we use a first order approximation to convert the optimization problem and provide an iterative power allocation algorithm to find the globally optimal solution. Simulation results show that our proposed algorithm is superior to orthogonal frequency division multiple access (OFDMA) scheme and average power allocation scheme. © 2018 IEEE.

关键词： Frequency division multiple access

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Secure beamformer design for cognitive satellite terrestrial networks 4

Secure beamformer design for cognitive satellite terrestrial...

引用

4th IEEE International Conference on Computer and communications, ICCC 2018

作者： Yin, Chunyan Lin, Zhi Tao, Xiangshuai Ouyang, Jian Lin, Min Panagopoulos, Athanasios D. Ministry of Education Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing China College of Communications Engineering Army Engineering University of PLA Nanjing China Nanjing Institute of Telecommunication Technology Nanjing China School of Electrical and Computer Engineering National Technical University of Athens Zografou15780 Greece

ISBN: (纸本)9781538683392

This paper proposes a beamforming (BF) scheme based on multi-objective optimization (MOO) for a cognitive satellite-terrestrial network (CSTN), where the eavesdroppers (Eves) attempt to intercept the private message conveyed to an intended user. By considering that the maximization of achievable secrecy rate (ASR) and the minimization of transmit power can not be achieved simultanesouly, we adopt artificial noise (AN) and apply the weighted Tchebycheff approach to formulate a multi-object optimization problem. Then, by introducing several auxiliary variables, applying semidefinite programming (SDP) and means of Taylor approximation, the original nonconvex MOO problem is transformed into a convex one with a series of linear constraints, and the BF weight vector and AN vector can be obtained. Finally, simulation results are given to illustrate the tradeoff between the conflicting objectives and the superiority of the proposed algorithm in comparison with the commonly used schemes. © 2018 IEEE.

关键词： Beamforming

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