检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

双特征层次嵌入的多维时序异常检测方法

计算机工程与应用 2024年第21期60卷 142-153页

作者：陈文礼苏宇陈玲俐高欣程瑛颖邹波国网重庆市电力公司营销服务中心计量技术部重庆400023 北京邮电大学人工智能学院北京100876 国网重庆市电力公司市场营销部重庆400014

开展多维时序特征下的工业实体设备实时运行状态在线异常检测,对维护复杂工业系统稳定运行、推动国家经济发展提质增效具有重要意义。针对现有异常检测方法对时序数据高度非线性的时间依赖关系及其模式多样的维度耦合关系分析不足的问题... 详细信息

开展多维时序特征下的工业实体设备实时运行状态在线异常检测,对维护复杂工业系统稳定运行、推动国家经济发展提质增效具有重要意义。针对现有异常检测方法对时序数据高度非线性的时间依赖关系及其模式多样的维度耦合关系分析不足的问题,综合考虑监控数据分布未知导致训练数据中可能掺杂噪声或异常数据的情况,提出双特征层次嵌入的多维时序异常检测方法。通过循环神经网络对时序特征数据进行处理,引入流模型仿射机制拓展数据分布并得到时间嵌入变量,捕捉长时间序列的全局及局部特征;与此同时,利用变分自编码器将多维输入映射到潜空间,共享时间嵌入的流模型参数,基于门控循环单元对维度间的耦合关系进一步关联分析,充分挖掘多维时序数据的时间依赖性和维度相关性,提高异常检测准确率。在5个权威公开的多维时序数据集上开展实验,与12种典型时序异常检测方法进行对比,所提算法在多种评价指标上的平均排名均位列第一,验证了所提方法的先进性和有效性。

关键词：多维时序异常检测循环神经网络变分自编码器流模型层次特征嵌入

Simulating robust far-field coupling to traveling waves in large three-dimensional nanostructured high-Q microresonators

在线全文

学校读者我要写书评

暂无评论

photonics research 2019年第9期7卷 967-976页

作者： LEI CHEN cheng li YU-MIN liU JUDITH {3. EUAN MCLEOD State Key Laboratory of Information photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing100876China College of Optical Sciences University of ArizonaTucsonArizona85721USA Dep.r.ment of Biomedical Engineering University of ArizonaTucsonArizona85721USA

Ultra-high quality(Q) whisp.r.ng gallery mode(WGM) microtoroid optical resonators have demonstrated highly sensitive biomolecular detection down to the single molecule limit;however, the lack of a robust coupling method has prevented their widespread adoption outside the laboratory. We demonstrate through simulation that a phased array of nanorods can enable free-space coupling of light both into and out of a microtoroid while maintaining a high Q. To simulate large nanostructured WGM resonators, we developed a new ap.r.ach known as FloWBEM,which is an efficient and compact 3. wedge model with custom boundary conditions that accurately simulate the resonant Fano interference between the traveling WGM waves and a nanorod array. Depending on the excitation conditions, we find loaded Q factors of the driven system as high as 2.1 × 10~7 and signal-to-background ratios as high as 3.86%, greater than the noise levels of many commercial detectors. These results can drive future exp.r.mental implementation.

关键词： domain Simulating robust far-field coupling to traveling waves in large three-dimensional nanostructured high-Q microresonators WGM

Formation and causes of NO_x pollution on the east side of the Taihang Mountains in china

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2011年第19期56卷 2044-2049页

作者： TIAN HeZhong WANG Yan ZHAO Dan CHAI FaHe xing ZiShan cheng Ke State Key Joint Laboratory of Environmental Simulation & pollution Control School of Environment Beijing Normal University Beijing 100875 China Chinese research Academy of Environmental Sciences Beijing 100012 China School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China

Tropospheric column amounts of NO 2 from OMI/Aura products were applied to investigate the seasonal variation of NO x on the east side of the Taihang Mountains (ESTM) in china. The NO 2 concentration varied seasonally, with winter maxima and summer minima. To explore the causes of the heavy NO 2 pollution in this region, wind field simulations were conducted by using the Fifth-Generation NCAr/penn State Mesoscale Model (MM5). MM5 simulations showed that wind directions in the ESTM region were dominated by northeasterly and northwesterly winds throughout the year and to a lesser degree by southwesterlies. Elevated NO 2 concentrations (higher than 50×10 15 molec/cm 2 ) occurred in three meteorological situations: convergent wind fields (5 days), northeasterly winds (2 days), and calm days (1 day) in January. Although the local anthropogenic NO x emission strength was not so high as that in other developed areas, the calms and frequent occurrence of convergent wind fields, as well as unfavorable terrains for diffusion, resulted in the accumulation of atmospheric pollutants and hence heavy NO x pollution. Furthermore, long-distance NO x transp.r.ation from the beijing-Tianjin-Tangshan region to the ESTM area could be seen when the wind was from a northeasterly direction, especially under high wind speeds.

关键词：氮氧化物氮污染原因山东中国二氧化氮浓度宾夕法尼亚州立大学 ESTM

Low-overhead fault-tolerant error correction scheme based on quantum stabilizer codes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese physics B 2022年第4期31卷 143-150页

作者： Xiu-Bo Chen li-Yun Zhao Gang Xu xing-Bo pan Si-Yi Chen Zhen-Wen cheng Yi-Xian Yang Information Security Center State Key Laboratory of Networking and Switching TechnologyBeijing University of Posts and TelecommunicationsBeijing 100876China School of Information Science and Technology North China University of TechnologyBeijing 100144China Advanced Cryptography and System Security Key Laboratory of Sichuan province Chengdu 610025China

Fault-tolerant error-correction(FTEC)circuit is the foundation for achieving reliable quantum computation and remote ***,designing a fault-tolerant error correction scheme with a solid error-correction ability and low overhead remains a significant *** this pa{3.a low-overhead fault-tolerant error correction scheme is proposed for quantum communication ***,syndrome ancillas are pre{3.d into Bell states to detect errors caused by channel *** propose a detection a{3.ach that reduces the propagation path of quantum gate fault and reduces the circuit depth by splitting the stabilizer generator into X-type and ***,a syndrome extraction circuit is equipped with two flag qubits to detect quantum gate faults,which may also introduce errors into the code block during the error detection ***,analytical results are provided to demonstrate the fault-tolerant {3.ormance of the proposed FTEC scheme with the lower overhead of the ancillary qubits and circuit depth.

关键词： fault-tolerant error correction quantum stabilizer code gate fault quantum circuit

Few-mode vertical-cavity surface-emitting lasers for space-division multiplexing

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2017年第9期38卷 42-47页

作者： Yaman su lijuan Yu Xia Guo xing Zhang Jianguo liu Ninghua Zhu State Key Laboratory of Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

In order to choose the prop.r.radius of oxide ap.r.ure for few-mode vertical-cavity surface-emitting lasers （VCSELs）, the influences of oxide ap.r.ure size on the multi-transverse-mode behaviors are investigated in detail. By establishing the effective refractive index model to simulate VCSELs with different radii of oxide ap.r.ures, the wavelength and corresponding order of different modes are obtained. VCSELs with three kinds of oxide ap.r.ures are manufactured. Then the multi-transverse-mode spectra and near-field are measured. It is found that when the radius is between 1.5 and 4.5μm, few-mode VCSELs can be implemented. The 2.5μm VCSEL manufactured in this pap.r.only emits Lp01 mode and Lp21 mode. Since the space distance between the two modes is 2μm, it is expected to realize direct-modulation few-mode VCSELs by channel etching or ion implantation between the two modes.

关键词： few-mode VCSELs oxide ap.r.ure space-division multiplexing

基于中继选择和协作MIMO的两跳WSNs能效性能

在线全文

学校读者我要写书评

暂无评论

北京邮电大学学报 2018年第3期41卷 63-68页

作者：易晓庆苏少花刘星成邹恩中山大学电子与信息工程学院广州510006 中山大学新华学院信息科学学院广州510520

为解决无线传感器网络（WSNs）的能量效率问题,构建了两跳（WSNs）系统模型.针对两跳模型中的中继选择策略进行了优化,分别提出了切换检测合并、带后验选择的切换检测合并中继选择策略,节省了中继节点的检测次数,从而节省了系统能耗.在... 详细信息

为解决无线传感器网络（WSNs）的能量效率问题,构建了两跳（WSNs）系统模型.针对两跳模型中的中继选择策略进行了优化,分别提出了切换检测合并、带后验选择的切换检测合并中继选择策略,节省了中继节点的检测次数,从而节省了系统能耗.在中继处加入协作多输入多输出（MIMO）的思想,进一步提升了系统的能效性能.理论和仿真结果表明,提出的切换检测合并和切换检测合并中继选择策略在能效性能上均比传统的选择合并策略优越,特别是切换检测合并策略在牺牲中断概率性能的情况下能效性能最好.

关键词：无线传感器网络多输入多输出中继选择中断概率能量效率

在线全文

学校读者我要写书评

暂无评论

云原生数据湖服务平台的设计与实现

计算机技术与发展 2024年第2期34卷 17-22页

作者：魏文定鄂海红王曦宋美娜宿兴辉北京邮电大学计算机学院(国家示范性软件学院) 北京100876 中国科学院信息工程研究所北京100085 联洋国融(北京)科技有限公司北京100088

云原生数据湖已经成为数据管理和分析领域的研究热点,相关技术和应用也得到了广泛的关注和探索。数据湖部署存在着成本高、组件之间兼容性差等问题,存算不分离制约着数据湖平台延展性,缺乏完备的数据入湖体系容易引起数据湖沼泽的形成,... 详细信息

云原生数据湖已经成为数据管理和分析领域的研究热点,相关技术和应用也得到了广泛的关注和探索。数据湖部署存在着成本高、组件之间兼容性差等问题,存算不分离制约着数据湖平台延展性,缺乏完备的数据入湖体系容易引起数据湖沼泽的形成,导致用户无法从中提取数据价值。该文设计并实现了云原生数据湖服务平台,平台以Kubernetes为底层构建云原生环境,结合容器技术将数据湖组件镜像化,同时设计数据湖存算分离方案来提高数据湖平台的可扩展性和可移植性,并配合监控、组装生产线将镜像容器化,实现数据湖上云操作。并建立用户入湖作业与云原生计算引擎之间的桥梁,对入湖信息进行预处理,提供多类型作业以满足多元化入湖场景,以统一catalog的方式将数据写入数据湖中。实际运行结果表明,该平台既提高了数据湖平台的灵活性和可靠性,又确保了元数据和数据资产的规范性存储。

关键词：云原生数据湖大数据生产线数据湖上云

Wronskian Form of N-Solitonic Solution for a Variable-Coefficient Korteweg-de Vries Equation with Nonuniformities

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical physics 2008年第11期50卷 1185-1188页

作者： CAI Ke-Jie TIAN Bo ZHANG cheng ZHANG Huan MENG Xiang-Hua LU xing GENG Tao liU Wen-Jun School of Science P.O. Box 122 Beijing University of Posts and Telecommunications Beijing 100876 China State Key Laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100083 China Key Laboratory of Optical Communication and lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

By the symbolic computation and Hirota method, the bilinear form and an auto-Backlund transformation for a variable-coemcient Korteweg-de Vries equation with nonuniformities are given. Then, the N-solitonic solution in terms of Wronskian form is obtained and verified. In addition, it is shown that the （N - 1）- and N-solitonic solutions satisfy the auto-Backlund transformation through the Wronskian technique.

关键词： variable-coefficient KdV equation bilinear auto-Bocklund transformation N-solitonic solution Wronskian determinant

在线全文

学校读者我要写书评

暂无评论

基于LSTM的多站点协作波束切换算法

中国电子科学研究院学报 2024年第3期19卷 239-247页

作者：王海洋何兴文孙海蓬王其盛苏俊浩张志龙山东电力工程咨询院有限公司山东济南250100 中兴通讯股份有限公司上海200120 北京邮电大学信息与通信工程学院北京100876

毫米波频段拥有非常丰富的频谱资源,支持更高速的数据传输,因此成为通信领域近年来的研究热点。基于大规模输入输出(Massive Multiple Input Multiple Output,mMIMO)的波束成形技术可以有效补偿毫米波的高路损,是5G毫米波通信中的一项... 详细信息

毫米波频段拥有非常丰富的频谱资源,支持更高速的数据传输,因此成为通信领域近年来的研究热点。基于大规模输入输出(Massive Multiple Input Multiple Output,mMIMO)的波束成形技术可以有效补偿毫米波的高路损,是5G毫米波通信中的一项关键技术。但是在高速移动场景下,信道变化加速,必须进行频繁的波束切换才能保证良好的通信质量,故而大大增加了信令开销与资源消耗。如何在高动态场景下降低波束切换开销、提升波束切换速度与效率成为关键问题。针对直射径(light of Sight,LOS)被遮挡情况下的复杂信道环境,文中提出了一种基于长短期记忆(Long Short Term Memory,LSTM)网络的多站点协作波束切换算法,根据过去一段时间的波束信息,学习信道环境与服务波束序号的内在联系,并预测当前时刻切换的最佳波束。仿真结果表明,与基于当前信道环境信息的遍历搜索算法相比,所提波束切换算法在上行发射功率较高时性能接近,在上行发送功率较低时,性能更优,体现了所提算法的优势。

关键词：波束切换站点协作长短期记忆网络