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Pulse Amplification in Dispersion-Decreasing Fibers with Symbolic Computation

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communications in Theoretical Physics 2009年第12期52卷 1076-1080页

作者： lIU Wen-jun TIAN Bo XU Tao CAI Ke-Jie ZHANG Huan school of Science Beijing University of Posts and Telecommunications P.O. Box 122 Beijing 100876 China State Key laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100083 China Key laboratory of information Photonics and Optical communication （BUPT） Ministry of Education Beijing University of Posts and Telecommunications P.O. Box 128 Beijing 100876 China

The pulse amplification in the dispersion-decreasing fiber （DDF） is investigated via symbolic computation to solve the variable-coefficient higher-order nonlinear Schrfdinger equation with the effects of third-order dispersion, self-steepening, and stimulated Raman scattering. The analytic one-soliton solution of this model is obtained with a set of parametric conditions. Based on this solution, the fundamental soliton is shown to be amplified in the DDF. The comparison of the amplitude of pulses for different dispersion profiles of the DDF is also performed through the graphical analysis. The results of this paper would be of certain value to the study of signal amplification and pulse compression.

关键词： fundamental soliton pulse amplication variable-coefficient higher-order nonlinear Schrodingerequation symbolic computation dispersion-decreasing fiber

High-Performance Photo-Modulated Thin-Film Transistor Based on Quantum dots/Reduced Graphene Oxide Fragment-Decorated ZnO Nanowires

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Nano-Micro letters 2016年第3期8卷 247-253页

作者： Zhi Tao Yi-an Huang xiang liu Jing Chen Wei lei Xiaofeng Wang lingfeng Pan Jiangyong Pan Qianqian Huang Zichen Zhang school of Electronic Science and engineering Southeast University State Key laboratory of Precision Measurement Technology and Instruments Collaborative Innovation Center for Micro/Nano Fabrication Device and System Department of Precision Instrument Tsinghua University school of information and communication engineering Beijing University of Posts and Telecommunications Institute of Semiconductors Chinese Academy of Science

In this paper, a photo-modulated transistor based on the thin-film transistor structure was fabricated on the flexible substrate by spin-coating and magnetron sputtering. A novel hybrid material that composed of Cd Se quantum dots and reduced graphene oxide(RGO) fragment-decorated ZnO nanowires was synthesized to overcome the narrow optical sensitive waveband and enhance the photo-responsivity. Due to the enrichment of the interface and heterostructure by RGO fragments being utilized, the photo-responsivity of the transistor was improved to 2000 AW^(-1) and the photo-sensitive wavelength was extended from ultraviolet to visible. In addition, a positive back-gate voltage was employed to reduce the Schottky barrier width of RGO fragments and ZnO nanowires. As a result, the amount of carriers was increased by 10 folds via the modulation of back-gate voltage. With these inherent properties, such as integrated circuit capability and wide optical sensitive waveband, the transistor will manifest great potential in the future applications in photodetectors.

关键词： Thin-film transistor Quantum dots Reduced graphene oxide ZnO nanowires

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基于音视频特征融合的情感识别方法研究

重庆理工大学学报（自然科学） 2022年第1期36卷 120-127页

作者：帖云程慧杰靳聪李小兵齐林郑州大学信息工程学院郑州450001 中国传媒大学信息与通信工程学院北京100024 中央音乐学院北京100031

传统的视频情感识别工作主要集中在面部表情、人体的动作行为等,忽略了场景和对象中包含大量的情感线索及不同对象之间的情感关联。因此,提出了一个基于视觉关系推理和跨模态信息学习的音视频特征融合网络模型用于预测视频情感。模型主... 详细信息

传统的视频情感识别工作主要集中在面部表情、人体的动作行为等,忽略了场景和对象中包含大量的情感线索及不同对象之间的情感关联。因此,提出了一个基于视觉关系推理和跨模态信息学习的音视频特征融合网络模型用于预测视频情感。模型主要包括三部分:对象间的情感关系推理、声学特征提取、跨模态交互融合。首先,采用Mask R-CNN模型提取出包含物体的区域并提取出相应的特征序列,利用图注意力网络对视频帧中的不同区域之间的情感关联进行推理,找到视频帧中的关键区域;然后,利用双向长短时记忆网络提取对数梅尔频谱片段的帧级上下文信息,对视觉信息进行补充;最后,将多头注意力机制应用到跨模态交互融合模块中去学习不同模态信息之间的隐藏关联,并将利用跨模态注意得到的音视频特征利用门控神经网络进行融合。所提出的模型在数据集Video Emotion-8和Ekman上具有较好的精确度。

关键词：情感识别情感关系推理跨模态交互图卷积神经网络多头注意力机制

Distributed interference suppression scheme for multi-cell uplink OFDMA system based on non-cooperative game

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The Journal of china Universities of posts and telecommunications 2011年第2期18卷 65-71页

作者： CHANG ling-jun TANG Bi-hua XIE Gang ZENG ling-kang lIU Kai-ming school of Electronic engineering Beijing University of Posts and Telecommunications Beijing 100876 China school of information and communication engineering Beijing University of Posts and Telecommunications Beijing 100876 China

In this paper,a distributed interference suppression scheme is proposed for multi-cell uplink orthogonal frequency division multiple access（OFDMA） ***,we model resource allocation process as a non-cooperative *** we show the concept of Nash equilibrium（NE） and investigate its existence and uniqueness in *** enhance the performance of multi-cell OFDMA system,the further improvement process based on NE is *** adjustable parameters are set to make the system achieve different tradeoffs between the total capacity and *** results show that the proposed scheme can greatly improve the system performance comparing with conventional scheme.

关键词： multi-cell non-cooperative game OFDMA uplink ICI

Multicast resource allocation with min-rate requirements in OFDM systems

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The Journal of china Universities of posts and telecommunications 2010年第3期17卷 24-30,51页

作者： XU Wen-jun HE Zhi-qiang NIU Kai lIN Jia-ru WU Wei-ling school of information and communication engineering Beijing University of Posts and Telecommunications Beijing 100876 China

This article addresses the multicast resource allocation problem with min-rate requirement constraints in orthogonal frequency division multiplexing （OFDM） systems. Due to the prohibitively high complexity for nonlinear and combinatorial optimization, the original problem is relaxed and reformulated to form a standard optimization problem. By theoretical derivation according to the Karush-Kuhn-Tucker （KKT） conditions, two propositions are presented as the necessary criteria for optimality. Furthermore, a two-step resource allocation scheme, including subcarrier assignment and power allocation, is proposed on a basis of the propositions for practical implementation. With the rain-rate based multicast group order, subcarriers are assigned in a greedy fashion to maximize the capacity. When subcarrier assignment is determined, the proposed power allocation can achieve the optimal performance for the rain-rate constrained capacity maximization with an acceptable complexity. Simulation results indicate that the proposed scheme approximates to optimal resource allocation obtained by exhaustive search with a negligible capacity gap, and considerably outperforms equal power distribution. Meanwhile, multicast is remarkably beneficial to resource utilization in OFDM systems.

关键词： OFDM multicast resource allocation min-rate requirements

基于贝叶斯网络的多方关联数据访问安全风险识别模型研究

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电子技术应用 2024年第9期50卷 9-17页

作者：齐俊周小明许超赵景宏刘大禾沈阳工业大学电气工程学院辽宁沈阳110000 国网辽宁省电力有限公司信息通信分公司辽宁沈阳110000 国网辽宁省电力有限公司辽宁沈阳110000 北京邮电大学计算机学院北京100876

对于现代电力系统的数据中台而言,识别用户访问数据过程中的数据推断风险尤为关键。特别是多个用户合谋窃取数据的行为,可能会造成从非敏感数据推断出敏感数据,导致敏感数据泄露,严重威胁电力调度和国家安全。传统的访问控制机制无法识... 详细信息

对于现代电力系统的数据中台而言,识别用户访问数据过程中的数据推断风险尤为关键。特别是多个用户合谋窃取数据的行为,可能会造成从非敏感数据推断出敏感数据,导致敏感数据泄露,严重威胁电力调度和国家安全。传统的访问控制机制无法识别这种风险。为此,提出一种基于贝叶斯网络的多方关联数据安全风险识别模型MPA-BN,综合考虑用户访问行为、时间模式、接口类型和数据交互方式,利用贝叶斯网络分析用户与服务接口之间的访问关系,深入挖掘数据之间的依赖关系和概率特征,识别数据中台对外服务接口的相关性以及用户组合的潜在风险。本研究使用的数据集来自电力公司数据中台的脱敏日志,其中包含10000个访问用户,生成日志的条目约100万。实验结果表明,该模型能够有效识别多用户合谋窃取敏感数据的风险,为电力系统数据安全提供更有力的保障。

关键词：数据中台数据推断风险贝叶斯网络隐私保护

Performance analysis of cooperative diversity for two-way multi-relay system with channel estimation error

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The Journal of china Universities of posts and telecommunications 2011年第3期18卷 41-46页

作者： WANG Si-ye XU Wen-jun HE Zhi-qiang NIU Kai WU Wei-ling school of information and Telecommunication engineering Beijing University of Posts and Telecommunications Beijing 100876 China

In this work, we consider an amplify-and-forward two-way multi-relay system for wireless communication and mvesngate me effect of channel estimation error on the error rate performance. With the derivation of effective signal-to-noise ratio at the transceiver and its probability density function, we can get approximate expression for average bit error rate. Simulation results are performed to verify the analytical results.

关键词： cooperative diversity two-way multi-relay Rayleigh fading channels amplify-and-forward relaying channel estimation error error probability

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一种低空遮挡场景感知增强方案研究

移动通信 2024年第4期48卷 61-65页

作者：相天麒陈蔚燕范雯周娇高月红张欣北京邮电大学信息与通信工程学院北京100876 中国移动通信有限公司研究院北京100032

随着低空无人机业务的稳步快速增长,低空场景的通感一体化已成为低空经济发展中必不可少的关键一环,利用现有5G基站进行低空通感一体改造也成为研究热点。对于低空覆盖感知中的遮挡问题,提出利用一种电磁可控智能面及边缘提高感知性能,... 详细信息

随着低空无人机业务的稳步快速增长,低空场景的通感一体化已成为低空经济发展中必不可少的关键一环,利用现有5G基站进行低空通感一体改造也成为研究热点。对于低空覆盖感知中的遮挡问题,提出利用一种电磁可控智能面及边缘提高感知性能,并提出了性能评估框架,以分析不同的感知方式和电磁操控机制的性能。仿真验证表明,在所研究的低空场景通感一体感知任务中,电磁操控机制的加入可以有效提升无人机感知概率,同时被动感知方式优于主动感知方式,而典型空-地场景下所提出的绕射增强结构的性能表现也优于智能反射面。

关键词：智能反射面及边缘感知增强低空无人机

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Image label transfer: Short video labelling by using frame auto-encoder

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The Journal of china Universities of posts and telecommunications 2020年第1期27卷 92-99页

作者： lü Chaohui Huang Yiyang school of information and communication engineering Communication University of ChinaBeijing 100024China beijing Key laboratory of Modern Entertainment Technology Communication University of ChinaBeijing 100024China Key laboratory of Acoustic Visual Technology and Intelligent Control System Ministry of Culture and TourismBeijing 100024China

Short videos on the Internet have a huge amount, but most of them are unlabeled. In this paper, a rough short video labelling method based on the image classification neural network is proposed. Convolutional auto-encoder is applied to train and learn unlabeled video frames, in order to obtain feature in the specific level. With these features, the video key-frames are extracted by the feature clustering method. These key-frames which represent the video content are put into an image classification network, so that the labels of every video clip can be got. In addition, the different architectures of convolutional auto-encoder are estimated, and a better performance architecture through the experiment result is selected. In the final experiment, the video frame features from the convolutional auto-encoder are compared with those from other extraction methods, where it illustrates remarkable results by the proposed method.

关键词： image feature video labelling convolutional neural network auto-encoder cluster key-frame