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

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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A RGB-D face recognition approach without confronting the camera

A RGB-D face recognition approach without confronting the ca...

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IEEE International Conference on Computer and communications, ICCC 2015

作者： Zhou, Wei Chen, Jian-Xin Wang, Lei Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing210003 China

ISBN: (纸本)9781467381253

Face recognition research mainly focuses on traditional 2D color images, which is extremely susceptible to be affected by external factors such as various viewpoints and has limited recognition accuracy. In order to achieve improved recognition performance, as well as the 3D face holds more abundant information than 2D, we present a 3D human face recognition algorithm using the Microsoft's Kinect. The proposed approach integrates the depth data with the RGB data to generate 3D face raw data and then extracts feature points, identifies the target via a two-level cascade classifier. Also, we build a 3D-face database including 16 individuals captured exclusively using Kinect. The experimental results indicate that the introduced algorithm can not only achieve better recognition accuracy in comparison to existing 2D and 3D face recognition algorithms when the probe face is exactly in front of Kinect sensor, but also can increase 9.3% of recognition accuracy compared to the PCA-3D algorithm when it is not confronting the camera. © 2015 IEEE.

关键词： Face recognition

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Modeling and analysis of anti-worm in P2P networks

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The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 112-118页

作者： TANG Xin WANG Ru-chuan SHAO Xing College of computer Nanjing University of Posts and Telecommunications Nanjing 210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology N anjing University of Posts and Telecommunications Ministry of Education Nanjing 210003 China

Anti-worm is an effective way to fight against malicious worm and has been followed closely by malicious worm researchers recently. However, active and passive confronting technologies in peer-to-peer （P2P） networks have not been studied in depth. This paper introduces both of them to fight against malicious worm in P2P networks. To study their effectiveness in P2P networks, this paper takes the topology degree in P2P networks into consideration and puts forward a four-state propagation model for active anti-worm and a five-state propagation model for passive anti-worm respectively. Both of the models are simplified in the case that size of a P2P network is large enough. The simulation results have not only validated the effectiveness of our propagation models but also evaluated the excellent performance of both active anti-worm and passive anti-worm.

关键词： P2P network anti-worm worm propagation model

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Quality-Aware Massive Content Delivery in Digital Twin-Enabled Edge networks

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China communications 2023年第2期20卷 1-13页

作者： Yun Gao Junqi Liao Xin Wei Liang Zhou School of Communications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

Massive content delivery will become one of the most prominent tasks of future B5G/6G ***,various multimedia applications possess huge differences in terms of object oriented(i.e.,machine or user)and corresponding quality evaluation metric,which will significantly impact the design of encoding or decoding within content delivery *** get over this dilemma,we firstly integrate the digital twin into the edge networks to accurately and timely capture Quality-of-Decision(QoD)or Quality-of-Experience(QoE)for the guidance of content ***,in terms of machinecentric communication,a QoD-driven compression mechanism is designed for video analytics via temporally lightweight frame classification and spatially uneven quality assignment,which can achieve a balance among decision-making,delivered content,and encoding ***,in terms of user-centric communication,by fully leveraging haptic physical properties and semantic correlations of heterogeneous streams,we develop a QoE-driven video enhancement scheme to supply high data *** results demonstrate the remarkable performance improvement of massive content delivery.

关键词： content delivery digital twin edge networks QoD QoE

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Spectrum allocation based on interference management in femtocell networks

Spectrum allocation based on interference management in femt...

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International Conference on Automatic Control and Artificial Intelligence, ACAI 2012

作者： Shi, Ju-Rong Zhu, Qi Jiangsu Key Lab of Wireless Communications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Jiangsu Nanjing 210003 China

ISBN: (纸本)9781849195379

In order to mitigate the interference between macrocell mobile stations (mMSs) and femtocells and allocate the spectrum efficiently, a graph coloring based clustering algorithm for channel allocation is proposed in this paper. Under the premise of guaranteeing the SINR requirements of mMSs, the algorithm determines the initial set of subchannels which can be used for each femtocell. Then according to the constructed interference graph of the femtocell networks, each femtocell mobile station(fMS) is allocated all the available spectrum resources dynamically. In this paper, we use an improved cluster algorithm to ensure the SINR of mMSs and maximize the femtocell throughput. Simulation results show that the proposed algorithm can reduce the outage probability of mMSs as well as improve the total throughput.

关键词： Graph theory

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Arbitrary-Oriented Ship Detection Based on Rotation Region Locating networks in Large Scale Remote Sensing Images 4

Arbitrary-Oriented Ship Detection Based on Rotation Region L...

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4th IEEE International Conference on Image, Vision and Computing, ICIVC 2019

作者： Liu, Xipeng Chen, Jianxin Kang, Bin Zhang, Xuguang Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing China

ISBN: (纸本)9781728123257

Although deep learning has dominated the ship detection domain, it still has two challenges: arbitrary-oriented densely arranged ships cause detection omissions and large scale image contains redundant areas. This paper proposes an effective convolutional neural network framework for arbitrary-oriented ship detection in large scale and complex scenes. In this framework, we propose Cumulative Feature Pyramid networks for multi-receptive-field feature fusion, which enhances high-level semantic information at all scales. Based on the outputs of Region Proposal networks, Rotation Region Locating network predicts rotation bounding box of arbitrary-oriented ships and adopts rotation intersection over union to avoid the effect of ship dense arrangement. For large scale scenes, No-Ship Area Suppression uses OTSU algorithm to generate binary mask and then filter out non-ship regions to reduce redundant computations. Additionally, we firstly build a remote sensing image dataset for ship detection, which contains 4237 images and over 21200 ships. Experimental comparisons with the state-of-the-art approaches validate the effectiveness, accuracy and robustness of the proposed method. © 2019 IEEE.

关键词： Ships

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Rapid computation of i-vector

Rapid computation of i-vector

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Speaker and Language Recognition Workshop, Odyssey 2016

作者： Xu, Longting Lee, Kong Aik Li, Haizhou Yang, Zhen Broadband Wireless Communication and Sensor Network Technology Key Lab Nanjing University of Posts and Telecommunications China Singapore

I-vector has been one of the state-of-the-art techniques in speaker recognition. The main computational load of the standard i-vector extraction is to evaluate the posterior covariance matrix, which is required in estimating the i-vector. This limits the potential use of i-vector on handheld devices and for large-scale cloud-based applications. Previous fast approaches focus on simplifying the posterior covariance computation. In this paper, we propose a method for rapid computation of i-vector which bypasses the need to evaluate a full posterior covariance thereby speeds up the extraction process with minor impact on the recognition accuracy. This is achieved by the use of subspace-orthonormalizing prior and the uniform-occupancy assumption that we introduce in this paper. From the experiments conducted on the extended core task of NIST SRE'10, we obtained significant speed-up with modest degradation in performance over the standard i-vector. © Odyssey 2016: Speaker and Language Recognition Workshop. All rights reserved.

关键词： Covariance matrix

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Compressive Wideband Spectrum Sensing Based on Random Matrix Theory

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Journal of Donghua University(English Edition) 2015年第2期32卷 248-251页

作者：曹开田戴林燕杭燚灵张蕾顾凯冬 Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and Telecommunications College of Overseas Education Nanjing University of Posts and Telecommunications

Spectrum sensing in a wideband regime for cognitive radio network(CRN) faces considerably technical challenge due to the constraints on analog-to-digital converters(ADCs).To solve this problem,an eigenvalue-based compressive wideband spectrum sensing(ECWSS) scheme using random matrix theory(RMT) was proposed in this *** ECWSS directly utilized the compressive measurements based on compressive sampling(CS) theory to perform wideband spectrum sensing without requiring signal recovery,which could greatly reduce computational complexity and data acquisition *** the ECWSS,to alleviate the communication overhead of secondary user(SU),the sensors around SU carried out compressive sampling at the sub-Nyquist rate instead of ***,the exact probability density function of extreme eigenvalues was used to set the *** analyses and simulation results show that compared with the existing eigenvalue-based sensing schemes,the ECWSS has much lower computational complexity and cost with no significant detection performance degradation.

关键词： compressive wideband Spectrum overhead exact eigenvalue utilized instead considerably constraints

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Improved medical image registration based on mutual information and gradient information

Improved medical image registration based on mutual informat...

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2013 International Conference on Human Health and Medical Engineering, HHME 2013

作者： Zhang, Dengyin Tan, Liping Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781845648923

Image registration based on mutual information is widely employed in medical image processing. But this method may lead to the wrong result of registration due to the excessive local maximum points and low accuracy. As the imaging parameters of the same organs are changeless, the gray values from different images are related. Thus this paper constructed the weighted factors for the different gray pairs that represent the different registration accurate levels to improve the registration accuracy and robustness. Meanwhile, this paper introduced the difference between gradient modules which can reflect intensity of gray change on the basis of traditional gradient similarity metric function to improve accuracy. Tests prove that this new method has an improved attribute in aspects of the more obvious climaxes of parameters' curves, the finding of the extreme point, higher accuracy, and stronger robustness. © 2014 WIT Press.

关键词： Image registration

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BIPR: A new TCP variant over satellite networks

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Journal of China Universities of Posts and Telecommunications 2011年第SUPPL. 1期18卷 34-39页

作者： Xiao, Fu Sun, Li-Juan Wang, Ru-Chuan Fang, Yue-Chao College of Computer Science and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China

Standard TCP perform poorly in satellite networks since the long delay, high bit error ratio and other characters. A new TCP variant, called BIPR for satellite networks is presented in this paper. Using the binary increase of window growth function, long bandwidth-delay product can be overcome, while probe method is also adopted in BIPR for conquer the high bit error rates in satellite links. Simulation results show that good performances in terms of throughput, link utilization and RTT fairness can be achieved in satellite networks using our method. © 2011 The Journal of China Universities of Posts and Telecommunications.

关键词： Satellites

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