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Full-duplex two-way AF relaying systems with imperfect interference cancellation in Nakagami-m fading channels

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Science China(Information Sciences) 2021年第8期64卷 143-155页

作者： Jianping tong Caijun ZHONG College of Science Zhejiang University of Technology Department of Information and Communication Engineering Zhejiang University

Full-duplex(FD) two-way relaying has the potential to substantially improve the spectral efficiency of the system, and is regarded as an enabling technology for the next generation wireless communication systems. Nevertheless, the joint effect of residual interference and channel fading condition on the fundamental performance of FD two-way relaying systems remains unclear. Motivated by this, this study considers a general FD two-way amplify-and-forward(AF) relaying system with imperfect interference cancellation in the versatile Nakagami-m fading channels, and presents a detailed analytical investigation on the outage performance of the system. The findings of the paper suggest that the performance of the FD two-way AF relaying system depends heavily on the residual interference strength, fading condition parameter m, and signal-to-noise ratio(SNR). The FD scheme outperforms the half-duplex(HD) two-way relaying counterpart in the low and moderate SNR regime, while becomes inferior in the high SNR regime, owing to strong residual interference. Also, compared to the channel fading condition of the information transmission channels, the impact of the channel fading condition of the interference channel on the system performance is relatively insignificant. Moreover, it is desirable to deploy the FD scheme when the channel fading condition of the information transmission channels is good, since it can effectively alleviate the detrimental effect of residual interference.

关键词： full-duplex two-way relaying Nakagami-m fading outage probability sum throughput

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Application of Eigenkets of Bosonic Creation Operator in Deriving Some New Formulas of Associated Laguerre Polynomials

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Communications in Theoretical Physics 2008年第8期50卷 315-320页

作者： FAN Hong-Yi WANG tong-tong Department of Material Science and Engineering University of Science and Technology of China Hefei 230026 China Department of Physics Shanghai Jiao Tong University Shanghai 200030 China

Using the resolution of unity composed of bosonic creation operator＇s eigenkets and annihilation operator＇s un-normalized eigenket, which is a new quantum mechanical representation in contour integration form, we derive new contour integration expression of associated Laguerre polynomials L^ρm （｜z｜^2） and its generalized generating function formula. A series of recursive relations regarding to L^ρm （｜z｜^2） are also deduced in the context of the Fock representation by algebraic method.

关键词： bosonic creation operator Laguerre polynomials contour integration

Experimental Study on Inducement and Development of Flow Instabilities in a Centrifugal Compressor with Different Diffuser Types

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Journal of Thermal Science 2020年第2期29卷 435-444页

作者： XUE Xiang WANG tong Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai 200240China

A centrifugal compressor is a typical compressed air energy storage device. In order to ensure the safety of the compressed energy storage process in the compressor, the internal unsteady flow phenomena need to be closely monitored, especially some serious ones like stall and surge. It is necessary to explore the mechanism of flow instabilities under different conditions. A centrifugal air compressor was tested with a vaneless diffuser and a variable vaned diffuser with five different vane setting angles, respectively. Various diffuser types resulted in various modes of flow instabilities prior to surge. The vaneless region between the impeller and the diffuser was focused on. Multiple high-speed sensors were arranged along the circumferential direction. The pressure signals at all these positions were being measured and collected in real time as the compressor was slowly throttled into surge. This paper emphasizes on the influence of matching between the impeller and the diffuser on the flow instability. The experimental results showed that the diffuser vane setting angle affected the stall characteristics. Due to the asymmetry of the volute, the circumferential pressure distribution was always severely distorted prior to surge. A high-pressure region appeared near the volute tongue, and a low-pressure region was formed away from the volute tongue. In the case of the vaned diffuser with non-design installation angle and the vaneless diffuser, the rotating stall signal was originated in the low-pressure region and propagated circumferentially. However, in the case of the vaned diffuser with the design installation angle, the circumferential high-pressure region became the most sensitive region for the generation of stall, and another form of instability occurred there. Both the inducement and development of these flow instabilities have been studied. The dynamic experimental research on the compressor matching different types of diffusers could be a good case supple

关键词： compressed air energy storage centrifugal compressor flow instability stall

Real-time detection network for tiny traffic sign using multi-scale attention module

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Science China(Technological Sciences) 2022年第2期65卷 396-406页

作者： YANG TingTing tong Chao School of Computer Science&Engineering Beihang UniversityBeijing 100191China

As one of the key technologies of intelligent vehicles, traffic sign detection is still a challenging task because of the tiny size of its target object. To address the challenge, we present a novel detection network improved from yolo-v3 for the tiny traffic sign with high precision in real-time. First, a visual multi-scale attention module(MSAM), a light-weight yet effective module, is devised to fuse the multi-scale feature maps with channel weights and spatial masks. It increases the representation power of the network by emphasizing useful features and suppressing unnecessary ones. Second, we exploit effectively fine-grained features about tiny objects from the shallower layers through modifying backbone Darknet-53 and adding one prediction head to yolo-v3. Finally, a receptive field block is added into the neck of the network to broaden the receptive field. Experiments prove the effectiveness of our network in both quantitative and qualitative aspects. The m AP@0.5 of our network reaches 0.965 and its detection speed is55.56 FPS for 512 × 512 images on the challenging Tsinghua-Tencent 100 k(TT100 k) dataset.

关键词： tiny object detection traffic sign detection multi-scale attention module real-time

Neurocognitive Correlates of Statistical Learning of Orthographic-Semantic Connections in Chinese Adult Learners

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Neuroscience Bulletin 2020年第8期36卷 895-906页

作者： Xiuhong tong Yi Wang Shelley Xiuli tong Department of Psychology The Education University of Hong KongHong KongChina Institute of Psychological Sciences Hangzhou Normal UniversityHangzhou 310000China Human Communication Developmentand Information SciencesFaculty of EducationThe University of Hong KongHong KongChina

We examined the neural correlates of the statistical learning of orthographic-semantic connections in Chinese adult *** event-related potentials(ERPs) were recorded while participants were exposed to a sequence of artificial logographic characters containing semantic radicals carrying low,moderate,or high levels of semantic *** behavioral results showed that the mean accuracy of participants’ recognition of previously exposed characters was 63.1% that was significantly above chance level(50%),indicating the statistical learning of the regularities of semantic *** ERP data revealed a temporal sequence of the neural process of statistical learning of orthographic-semantic connections,and different brain indexes were found to be associated with this processing,i.e.,a clear N170-P200-N400 *** N170,the larger negative amplitudes were evoked by the high and moderate consistency than the low *** P200,the mean amplitudes elicited by the moderate and low consistency were larger than the high *** contrast,a larger N400 amplitude was observed in the low than moderate and high consistency;and more negative amplitude was elicited by the moderate than high *** propose that the initial potential shifts(N170 and P200) may reflect orthographic or graphic form identification,while the later component(N400) may be associated with semantic information analysis.

关键词： Orthography-semantic connection Statistical learning N170 P200 N400

A dynamic algorithm for trust inference based on double DQN in the internet of things

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Digital Communications and Networks 2024年第4期10卷 1024-1034页

作者： Xiaodong Zhuang Xiangrong tong School of Computer and Control Engineering Yantai UniversityYantai264005China

The development of the Internet of Things(IoT)has brought great convenience to ***,some information security problems such as privacy leakage are caused by communicating with risky *** is a challenge to choose reliable users with which to interact in the ***,trust plays a crucial role in the IoT because trust may avoid some *** usually choose reliable users with high trust to maximize their own interests based on reinforcement ***,trust propagation is time-consuming,and trust changes with the interaction process in social *** track the dynamic changes in trust values,a dynamic trust inference algorithm named Dynamic Double DQN Trust(Dy-DDQNTrust)is proposed to predict the indirect trust values of two users without direct contact with each *** proposed algorithm simulates the interactions among users by double ***,CurrentNet and TargetNet networks are used to select users for *** users with high trust are chosen to interact in future ***,the trust value is updated dynamically until a reliable trust path is found according to the result of the ***,the trust value between indirect users is inferred by aggregating the opinions from multiple users through a Modified Collaborative Filtering Averagebased Similarity(SMCFAvg)aggregation *** are carried out on the FilmTrust and the Epinions *** with TidalTrust,MoleTrust,DDQNTrust,DyTrust and Dynamic Weighted Heuristic trust path Search algorithm(DWHS),our dynamic trust inference algorithm has higher prediction accuracy and better scalability.

关键词： Internet of things Information security Reinforcement learning Trust propagation Trust inference

The Impact of Oil Shocks on Systemic Risk of the Commodity Markets

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Journal of Systems Science & Complexity 2024年第6期37卷 2697-2720页

作者： DAI Zhifeng WU tong College of Mathematics and Statistics Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in EngineeringChangsha University of Science and TechnologyChangsha 410114China

This study examines the influence of oil shocks on systemic risk spillover among the commodity ***,this paper uses the DCC-GARCH approach combined with the TVP-VAR model to calculate risk connectedness and the GARCH-MIDAS model to explore how oil shocks from different sources affect the risk spillover effects among the commodity *** results are the following:First,there are significant risk spillovers among the commodity markets with important time-varying characteristics and with sharp changes in times of *** industrial metals,agriculture,precious metals,and light energy commodity markets are risk recipients,and the energy and livestock commodity markets are risk ***,oil price shocks,particularly oil aggregate demand shocks,prominently affect the total risk connectedness among the commodity *** particular,the impact on the net risk spillover effect of different commodity market differs.

关键词： Commodity markets connectedness GARCH-MIDAS model oil price shocks systemic risk

Optimal Location Allocation Strategy of Gas-fired Unit in Transmission Network

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 229-237页

作者： Jiale Fan Xiaoyang tong the School of Electrical Engineering Southwest Jiaotong UniversityChengduChina

The gas-fired generation has recently become an important power source for power *** increasing integration of gas-fired units(GFUs)brings a problem of location allocation strategy for power system *** paper proposes a bi-level maximum-minimum optimal placement model of GFUs to improve the static voltage stability in the transmission *** the first stage,the locations of installed GFUs are optimized to improve the static voltage stability *** optimal installed capacity of GFUs is determined to minimize the operation costs and power losses in the second *** proposed mixed-integer nonlinear programming(MINLP)model is solved by second-order cone programming *** results in the IEEE 118-bus test system demonstrate the effectiveness of the proposed method and the static voltage stability can be improved.

关键词： Integrated energy systems gas-fired unit(GFU) static voltage stability optimal power flow

An accreting low magnetic field magnetar for the ultraluminous X-ray source in M82

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Research in Astronomy and Astrophysics 2015年第4期15卷 517-524页

作者： Hao tong Xinjiang Astronomical Observatory Chinese Academy of Sciences

One ultraluminous X-ray source in M82 has recently been identified as an accreting neutron star （named NuSTAR J095551＋6940.8）. It has a super-Eddington luminosity and is spinning up. An aged magnetar is more likely to be a low magnetic field magnetar. An accreting low magnetic field magnetar may explain both the super- Eddington luminosity and the rotational behavior of this source. Considering the effect of beaming, the spin-up rate is understandable using the traditional form of accretion torque. The transient nature and spectral properties of M82 X-2 are discussed. The theoretical range of periods for accreting magnetars is provided. Three observational appearances of accreting magnetars are summarized.

关键词： accretion -- pulsars: individual (NuSTAR J095551+6940.8) -- stars:magnetars -- stars: neutron