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Uncertainties of clock and shift operators for an electron in one-dimensional nonuniform lattice systems

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Chinese Physics B 2017年第11期26卷 441-445页

作者：巩龙延丁友根邓永强 Department of Applied Physics Nanjing University of Posts and Telecommunications institute of {1. processing and transmission Nanjing University of Posts and Telecommunications National Laboratory of Solid State Microstructures Nanjing University

The clock operator U and shift operator V are higher-dimensional Pauli operators. Just recently, tighter uncertainty relations with respect to U and V were derived, and we apply them to study the electron localization properties in several typical one-dimensional nonuniform lattice systems. We find that uncertainties △U^2 are less than, equal to, and greater than uncertainties △V^2 for extended, critical, and localized states, respectively. The lower bound LB of the uncertainty relation is relatively large for extended states and small for localized states. Therefore, in combination with traditional quantities,for instance inverse participation ratio, these quantities can be as novel indexes to reflect Anderson localization.

关键词： uncertainties Anderson localization nonuniform lattice systems mobility edge

A novel multi-relay cross-layer cooperative communication strategy based on Jackson queuing model

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Science China(Information Sciences) 2010年第4期53卷 842-853页

作者： XU XiaoRong1.2* & ZHENG BaoYu1.1.0} of {1. processing and transmission, Nanjing University of Posts and Telecommunications, Nanjing 21.003, China 2College of Telecommunication Engineering, Hangzhou Dianzi University, Hangzhou 31.01., China institute of {1. processing and transmission Nanjing University of Posts and Telecommunications Nanjing China College of Telecommunication Engineering Hangzhou Dianzi University Hangzhou China

A novel multi-relay cooperative communication strategy based on Jackson queuing model is pro-posed, which is implemented via a cross-layer design between the physical (PHY) layer and the medium access control (MAC) layer. In the PHY layer, we focus mainly on system outage performance by analyzing in detail the relationship between the SNR threshold and the outage probabilities. While in the MAC layer, system model is treated as a Jackson queuing network, and the queue discipline for each node is assumed to be GI/M/1.model. System throughput and delay performance for the proposed strategy are also illustrated. Simulation results of the proposed cross-layer scheme are presented to validate our theoretical derivations. It is revealed that, the number of cooperative nodes influences system outage performance at high spectral efficiency regimes in the PHY layer while the proposed strategy provides a better throughput and delay performance than conventional schemes in the MAC layer.

关键词： multi-relay cooperative communication cross-layer design Jackson queuing model outage prob- abilities GI/M/1.model system throughput delay performance

Phase diagram of a family of one-dimensional nearest-neighbor tight-binding models with an exact mobility edge

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Chinese Physics B 2017年第7期26卷 323-327页

作者：巩龙延赵小新 Department of Applied Physics Nanjing University of Posts and Telecommunications institute of {1. processing and transmission Nanjing University of Posts and Telecommunications National Laboratory of Solid State Microstructures Nanjing University

Recently, an interesting family of quasiperiodic models with exact mobility edges（MEs） has been proposed（***. Lett. 1.4 1.6601.201.））. It is self-dual under a generalized duality transformation. However, such transformation is not obvious to map extended（localized） states in the real space to localized（extended） ones in the Fourier space. Therefore,it needs more convictive evidences to confirm the existence of MEs. We use the second moment of wave functions, Shannon information entropies, and Lypanunov exponents to characterize the localization properties of the eigenstates, ***, we obtain the phase diagram of the model. Our numerical results support the existing analytical findings.

关键词： Anderson localization quasiperiodic model mobility edge

Micro-flow structure at regime transition from bubbling to turbulent fluidization in a fluidized bed

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Particuology 2024年第6期89卷 117-130页

作者： Chaoyu Yan Yue Yuan Xiaoyang Wei Jesse Zhu State Key Laboratory of Heavy Oil processing Beijing Key Laboratory of Process Fluid Filtration and SeparationCollege of Mechanical and Transportation EngineeringChina University of PetroleumBeijing 102249China China Beacons institute The University of NottinghamNingbo315100China Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioN6A 5B9Canada

Gas-solid fluidized beds have found extensive utilization in frontline manufacturing,in particular as low-velocity *** fluidization status,the bubbling or turbulent flow regime and the transition in between,determine the system performance in practical *** the convoluted hydrodynamics are quantitively evaluated through numerous data-processing methodologies,none of them alone can reflect all the critical information to identify the transition from the bubbling to the turbulent ***,this study was to exploit a coupling data processing methodology,in the combination of standard deviation,power spectrum density,probability density function,wavelet transform,and wavelet multiresolution method,to jointly explain the micro-flow structure at the regime transition from bubbling to turbulent *** transient differential pressure fluctuation was measured for the evaluation in a fluidized bed(0.267 m i.d.×2.5 m height)with FCC catalysts(d_(p)=65μm,ρ_(p)=1.80kg/m^(3))at different superficial gas velocities(0.02–1.4 m/s).The results show that the onset of turbulent fluidization starts earlier in the top section of the bed than in the bottom *** wavelet decomposition displays that the fluctuation of differential pressure mainly concentrates on the sub-signals with an intermediate frequency *** sub-signals could be synthesized into three types of scales(micro-scale,meso-scale,and macro-scale),representing the multi-scale hydrodynamics in the fluidized *** micro-scale signal has the characteristic information of bubbling fluidization,and the characteristic information of turbulent fluidization is mainly represented by the meso-scale *** work provides a systematic comprehension of fluidization status assessment and serves as an impetus for more coupling analysis in this sector.

关键词： Flow regime transition Bubbling fluidization Turbulent fluidization Micro-flow structure Differential pressure fluctuation

Bounds and constructions of optimal optical orthogonal codes with low correlation zone

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Science China(Information Sciences) 2019年第10期62卷 214-216页

作者： Chengqian XU School of Information Science and Engineering Yanshan University Hebei Key Laboratory of Information transmission and {1. processing Yanshan University

Dear editor,In optical code division multiple access (CDMA)systems, optical orthogonal codes (OOC) should exhibit the following correlations to reduce multiple access interference:the non-trivial correlation between a sequence and its shift sequence and the correlation between sequence and shift sequence of other sequences should be as low as possible [1. 2].Herein, the shift values of a sequence are randomly

关键词： Bounds and constructions of optimal optical orthogonal codes with low correlation zone Hamming

Handwritten digit recognition based on ghost imaging with deep learning

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Chinese Physics B 2021年第5期30卷 367-372页

作者： Xing He Sheng-Mei Zhao Le Wang institute of {1. processing and transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing 210003China

We present a ghost handwritten digit recognition method for the unknown handwritten digits based on ghost imaging(GI)with deep neural network,where a few detection signals from the bucket detector,generated by the cosine transform speckle,are used as the characteristic information and the input of the designed deep neural network(DNN),and the output of the DNN is the *** results show that the proposed scheme has a higher recognition accuracy(as high as 98%for the simulations,and 91.for the experiments)with a smaller sampling ratio(say 1..76%).With the increase of the sampling ratio,the recognition accuracy is *** with the traditional recognition scheme using the same DNN structure,the proposed scheme has slightly better performance with a lower complexity and non-locality *** proposed scheme provides a promising way for remote sensing.

关键词： ghost imaging handwritten digit recognition ghost handwritten recognition deep learning

QoS-guaranteed packet scheduling in wireless networks

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The Journal of China Universities of Posts and Telecommunications 2009年第2期16卷 63-67页

作者： ZHANG Deng-yin JIANG Juan ANANI Adi LI Hai-bo institute of {1. processing and transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China Department of Applied Physics and Electronics Umea University Umea 90187 Sweden

To guarantee the quality of service （QoS） of a wireless network, a new packet scheduling algorithm using cross-layer design technique is proposed in this article. First, the demand of packet scheduling for multimedia transmission in wireless networks and the deficiency of the existing packet scheduling algorithms are analyzed. Then the model of the QoS-gnaranteed packet scheduling （QPS） algorithm of high speed downlink packet access （HSDPA） and the cost function of packet transmission are designed. The calculation method of packet delay time for wireless channels is expounded in detail, and complete steps to realize the QPS algorithm are also given. The simulation results show that the QPS algorithm that provides the scheduling sequence of packets with calculated values can effectively improve the performance of delay and throughput.

关键词： packet scheduling QoS wireless network cross-layer design

Phase-matching quantum key distribution with light source monitoring

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Chinese Physics B 2022年第5期31卷 165-172页

作者： Wen-Ting Li Le Wang Wei Li Sheng-Mei Zhao institute of {1. processing transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing 210003China

The transmission loss of photons during quantum key distribution(QKD)process leads to the linear key rate bound for practical QKD systems without quantum *** matching quantum key distribution(PM-QKD)protocol,an novel QKD protocol,can overcome the constraint with a measurement-device-independent structure,while it still requires the light source to be *** assumption is not guaranteed in practice,leading to practical secure *** this paper,we propose a modified PM-QKD protocol with a light source monitoring,named PM-QKD-LSM protocol,which can guarantee the security of the system under the non-ideal source *** results show that our proposed protocol performs almost the same as the ideal PM-QKD protocol even considering the imperfect factors in practical ***-LSM protocol has a better performance with source fluctuation,and it is robust in symmetric or asymmetric cases.

关键词： phase-matching quantum key distribution source fluctuation light source monitoring

Design and implementation of improved watermarking system in WT domain

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 58-63页

作者： ZHANG Deng-yin CHEN Jia-ping SUN Jun-cai institute of Digital {1. and transmission Nanjing University of Posts s Nanjing 210003 China

This article presents a watermarking algorithm based on one-dimensional （1.D） chaotic map in wavelet transform （WT） domain. Traditional encryption and watermarking technologies in the WT domain are combined in this algorithm. First, the watermark is encoded by a chaotic sequence, which is generated by a key. On the basis of human visual system （HVS）, it is then divided into two parts and embedded into the low- and intermediate-frequency bands of three-layer WT domain. The encryption of the watermark and the choice of embedded areas based on the perceptivity not only confer the watermark with good invisibility but also with good robustness. Meanwhile, it is difficult to decrypt the watermark extracted from the WT domain.

关键词： watermarking chaotic map WT invisibility robustness