检索结果-南通市图书馆

Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation

Photonics Research 2024年第08期12卷 1785-1793页

作者： HUI LIU mingyang guo TIAN ZHANG JIAN DAI KUN XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications School of Electronic Engineering Beijing University of Posts and Telecommunications

Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources. Among these, optoelectronic oscillators（OEOs） and coupled optoelectronic oscillators（COEOs） have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase ***, the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters, presenting challenges in achieving both wide and rapid tuning capabilities. Here, we present a COEO featuring ultralow phase noise, flexible tuning capability, and high robustness. This is achieved through a quiet point（QP）-operated harmonic mode-locked fiber laser, which effectively mitigates optical amplifier noise and supermode competition, thus significantly diminishing the necessity for ultra-narrow electronic filters. Due to the liberated tuning ability, we present an oscillator that can be tuned from 2 GHz to 18 GHz, with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP operation. We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz, hopping resolution of 1.25 MHz, and fractional frequency stability below 6.1 × 10-12at 1 s averaging time when locked to a reference. The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.

关键词： Bandpass filters Beam splitters Microwave photonics Mode-locked fiber lasers Optical amplifiers Phase noise

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

发达国家高等教育数字化转型的新动向

引用

中国教育信息化 2024年第2期30卷 62-70页

作者：郭明旸华中师范大学教育学院湖北武汉430079

数字技术的发展和新冠疫情的冲击为高等教育机构带来新的机遇和挑战,高等教育数字化转型已经成为高等教育机构的优先事项。多个发达国家出台相关政策以支持高等教育机构的转型:通过基础设施建设提高高等教育的可获得性;维护高等教育中... 详细信息

数字技术的发展和新冠疫情的冲击为高等教育机构带来新的机遇和挑战,高等教育数字化转型已经成为高等教育机构的优先事项。多个发达国家出台相关政策以支持高等教育机构的转型:通过基础设施建设提高高等教育的可获得性;维护高等教育中的数字安全;加强高等教育机构和其他部门的协作。在发达国家政策的推动下,各国和高校纷纷采取数字化转型新举措和尝试,例如,打破单一的学分学位认证体系,利用技术改革高等教育评价体系以及促进混合式学习中教师和学生的发展。我国应积极借鉴发达国家的经验,制定高等教育数字化转型指南,积极推进高等院校教育教学革新,加强高等教育机构与信息技术企业的合作,走出高等教育数字化转型的中国特色实施路径,实现我国高等教育从学习革命到质量革命再到高质量发展的突破。

关键词：发达国家高等教育政策数字化转型新动向

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

基于A2C的匝道相联交叉口信号控制优化

引用

深圳大学学报（理工版） 2024年第2期41卷 192-201页

作者：宋太龙郭明洋陈一凡贺玉龙山东省交通科学研究院山东济南250031 北京市市政专业设计院股份公司北京100037 北京工业大学城市建设学部北京100124

城市快速路的交通运行效率对于整个城市的顺畅通行至关重要,在早晚高峰期间,受限于相连接辅路的交通承载能力,快速路上较大的交通流量无法顺利从出口匝道驶入目标路段,在匝道上形成排队现象,严重时会导致匝道回溢,使快速路上车道由于被... 详细信息

城市快速路的交通运行效率对于整个城市的顺畅通行至关重要,在早晚高峰期间,受限于相连接辅路的交通承载能力,快速路上较大的交通流量无法顺利从出口匝道驶入目标路段,在匝道上形成排队现象,严重时会导致匝道回溢,使快速路上车道由于被占用而产生交通瓶颈,造成较大的交通出行损失.利用深度强化学习算法进行出口匝道相关联的道路交叉口信号控制优化,将信号灯设为智能体,通过设置检测器,将快速路出口匝道及交叉口的交通运行情况作为智能体获取的状态信息,引入以辅路与出口匝道剩余通行能力之比为动态修正参数的奖励函数,在保证匝道交通运行效率下,完成交叉口信号优化过程.以中国北京市东三环快速路及某关联交叉口为例,借助交通仿真平台SUMO(simulation of urban mobility)及Traci库搭建仿真环境进行实验.结果表明,基于改进A2C(advantage actor critic)算法的信号控制方法在控制效果上优于传统信号控制以及基于深度Q网络(deep Q-network,DQN)算法的信号控制方法,在出行高峰期间能够有效降低匝道回溢的发生概率,有效改善辅道相联交叉口的通行效率.

关键词：智能交通匝道交叉口信号控制优化深度学习强化学习

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于图像显著性的空中光学伪装效果评估方法

引用

兵工自动化 2024年第9期43卷 7-12页

作者：张祥沙建军郭铭洋黄倩温远征哈尔滨工程大学智能科学与工程学院哈尔滨150001 哈尔滨工程大学青岛创新发展基地青岛266000 哈尔滨工程大学信息与通信工程学院哈尔滨150001

针对传统伪装效果评估在大场景空中图像不适用问题,提出一种基于图像显著性的空中光学伪装效果评估方法。采用频率调谐(frequency-tuned,FT)模型生成全局显著图和显著区域图,使用残余谱(spectrum residual,SR)模型生成局部显著图;根据... 详细信息

针对传统伪装效果评估在大场景空中图像不适用问题,提出一种基于图像显著性的空中光学伪装效果评估方法。采用频率调谐(frequency-tuned,FT)模型生成全局显著图和显著区域图,使用残余谱(spectrum residual,SR)模型生成局部显著图;根据显著图计算全局显著均值、显著区域占比和局部显著均值3个指标;通过熵权法综合3个指标得到综合显著性评估系数来量化评估,在林地和雪地背景下获取伪装目标空中光学图像进行实验验证。结果表明:该方法能较好地体现不同伪装效果的差异,优于目标背景相似度加权模型,且可根据显著图优化伪装方案。

关键词：图像显著性熵权法伪装评估空中光学图像

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

船舶超大空间火灾环境下人员疏散模型

引用

哈尔滨工程大学学报 2024年第1期45卷 53-61页

作者：张海鹏李语松陈淼郭明阳哈尔滨工程大学船舶工程学院黑龙江哈尔滨150001 哈尔滨工程大学烟台研究院山东烟台264000

针对船舶超大空间火灾对人员疏散能力的影响难以量化问题,本文基于元胞自动机理论,构建了一种行人个体自主分析火灾环境下温度和能见度影响的疏散模型(cellular automata model considering visibility and temperature, CAVT)。CAVT模... 详细信息

针对船舶超大空间火灾对人员疏散能力的影响难以量化问题,本文基于元胞自动机理论,构建了一种行人个体自主分析火灾环境下温度和能见度影响的疏散模型(cellular automata model considering visibility and temperature, CAVT)。CAVT模型采用Sigmoid函数和历史实验数据建立温度、能见度与人员运动能力的映射关系,基于FDS数值模拟结果建立火灾环境场对人员个体运动能力影响的时空耦合关系,使用熵值法计算温度场和能见度场在火灾环境场中的权重。以某客船超大空间为例开展研究分析,结果表明:火灾环境下人员疏散时间受火源功率影响较大,火源位置影响较小,出口宽度大于3 m,不影响疏散效率。与Pathfinder软件相比,CAVT模型可更准确模拟人员因高温和低能见度导致的运动能力的动态下降反馈。

关键词：船舶超大空间火灾 Sigmoid函数人员疏散熵值法元胞自动机能见度

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Curve Reconstruction Algorithm Based on Discrete Data Points and Normal Vectors

引用

Journal of Mathematical Research with Applications 2020年第1期40卷 87-100页

作者： mingyang guo Chongjun LI Department of Mathematics Dalian University of Technology

This paper presents a curve reconstruction algorithm based on discrete data points and normal vectors using B-splines. The proposed algorithm has been improved in three steps:parameterization of the discrete data points with tangent vectors, the B-spline knot vector determination by the selected dominant points based on normal vectors, and the determination of the weight to balancing the two errors of the data points and normal vectors in fitting ***, we transform the B-spline fitting problem into three sub-problems, and can obtain the B-spline curve adaptively. Compared with the usual fitting method which is based on dominant points selected only by data points, the B-spline curves reconstructed by our approach can retain better geometric shape of the original curves when the given data set contains high strength noises.

关键词： curve reconstruction curve fitting normal vector B-spline dominant point

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Effect of hand-ear acupuncture on chronic low-back pain: a randomized controlled trial

引用

Journal of Traditional Chinese Medicine 2019年第4期39卷 587-594页

作者： Luo Yong Yang Min Liu Tao Zhong Xiaolong Tang Wen guo mingyang Hu Yonghe Graduate College The People's Liberation Army Naval Medical UniversityShanghai 200433China Traditional Chinese Medicine Department The General Hospital of Western Theater CommandChengdu 610083China Traditional Chinese Medicine Department The General Hospital of Western Theater CommandChengdu 610083China The People's Liberation Army 32357 troops Chengdu 611630China

OBJECTIVE: To evaluate the effect of hand-ear acupuncture on chronic low-back pain(cLBP).METHODS: This was an open, randomized and controlled trial in The General Hospital of Western Theater Command, Sichuan Province. The trial was registered with ***, NCT02260284. All the 152 participates with cLBP were randomly assigned to hand-ear acupuncture(n = 54), standard acupuncture(n = 50), or usual care groups(n = 48).Eighteen treatments were provided over 7 ***-related dysfunction and symptom severity were assessed by the Roland-Morris Disability Questionnaire(RMDQ) and the Visual Analogue Scale(VAS), which were collected at baseline, 2 months and 6 months post to the ***: At 6 months, the RMDQ scores improved by 7.74 points of hand-ear acupuncture group. Significant improvement of VAS and RMDQ was observed in hand-ear acupuncture group(P < 0.001),but no significant changes of RMDQ were observed in both standard acupuncture group and usual care group. We also observed an overall efficacy rate of 88.89% in hand-ear acupuncture group, as evaluated by Diagnosis and Curative Effect Standard for Symptom pattern of Traditional Chinese Medicine, which was much higher than 45.84% in the usual care group(H = 16.000, P < 0.001).CONCLUSION: Both of the hand-ear acupuncture and standard acupuncture modes have beneficial and persistent effectiveness against cLBP compared with the usual care. Furthermore, hand-ear acupuncture is significantly more effective than the standardized acupuncture, especially in the long term.

关键词： Low back pain Acupuncture Visual analogue scale Questionnaire Randomized controlled trial

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Sanhuangwuji powder,anti-rheumatic drugs,and ginger-partitioned acupoint stimulation on the treatment of rheumatoid arthritis with peptic ulcer:a randomized controlled study

引用

Journal of Traditional Chinese Medicine 2015年第3期35卷 273-280页

作者： Liu Defang guo mingyang Hu Yonghe Liu Taihua Yan Jiao Luo Yong Yun Mingdong Yang Min Zhang Jun guo Linglin Department of Integrated Traditional and Western Medicinem on Rheumatism General Hospital of Chengdu Military Area Command PLA Department of Dermatology General Hospital of Chengdu Military Area Command Chinese People's Liberation Army

OBjECTIVE:To observe the efficacy and safety of oral Sanhuangwuji powder,anti-rheumatic drugs(ARDs),and ginger-partitioned acupoint stimulation at Zusanli(ST 36) on the treatment of rheumatoid arthritis(RA) complicated by peptic ***:This prospective randomized controlled study included 180 eligible inpatients and outpatients randomly assigned to an ARD treatment(n = 60),ginger-partitioned stimulation(n =60),or combination treatment(n = 60).Patients assigned to the ARD group were given oral celecoxib,methotrexate,and *** assigned to theginger-partitioned stimulation group were given ginger-partitioned acupoint stimulation at Zusanli(ST 36) in addition to the *** in the combination treatment group were given oral Sanhuangwuji powder,ginger-partitioned acupoint stimulation at Zusanli(ST 36),and *** patients were followed up for 2 months to evaluate clinical effects and *** study was registered in the World Health Organization database at the General Hospital of Chengdu Military Area Command Chinese People's Liberation Army(ChiCTR-TCC12002824).RESULTS:The combination treatment group had significantly greater improvements in RA symptoms,laboratory outcomes,and gastrointestinal symptom scores,compared with the other groups(P < 0.05).The peptic ulcer healing rate in the combination treatment group was significantly greater than that in the ARD treatment group(x^2 = 16.875,P < 0.05) and the ginger-partitioned stimulation group(x^2 = 6.171,P<0.05).CONCLUSION:Combination treatment with ginger-partitioned acupoint stimulation at Zusanli(ST36),oral Sanhuangwuji powder,and ARDs had a better clinical effect for RA with complicated peptic ulcer,compared with ARD treatmentalone or in combination with ginger-partitioned acupoint stimulation.

关键词： Arthritis,rheumatoid Peptic ulcer Point ST 36(Zusanli) Sanhuangwuji powder Randomized controlled trial

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A new state of matter of quantum droplets

引用

Frontiers of physics 2021年第3期16卷 3-6页

作者： mingyang guo Tilman Pfau 5.Physikalisches Institut and Center for Integrated Quantum Science and Technology Universität StuttgartPfaffenwaldring 5770569StuttgartGermany

Since the realization of Bose Einstein condensation(BEC)[1-3]and degenerate Fermi gases[4],ultracold quantum gases have become important platforms to study quantum phenomena and novel states of matter with precise control over both internal and external degrees of *** quantum gases arc typically dilute and weakly interacting,the interactions intrinsically determine their essential properties,such as the superfluidity of a BEC.

关键词： quantum gases dilute

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Exact Box-Constrained Economic Operating Region for Power Grids Considering Renewable Energy Sources

引用

Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 514-523页

作者： Huating Xu Bin Feng Chutong Wang Chuangxin guo Jian Qiu mingyang Sun College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

The growing integration of renewable energy sources manifests as an effective strategy for reducing carbon emissions. This paper strives to efficiently approximate the set of optimal scheduling plans(OSPs) to enhance the performance of the steady-state adaptive cruise method(SACM) of power grid, improving the ability of dealing with operational uncertainties. Initially, we provide a mathematical definition of the exact boxconstrained economic operating region(EBC-EOR) for the power grid and its dispatchable components. Following this, we introduce an EBC-EOR formulation algorithm and the corresponding bi-level optimization models designed to explore the economic operating boundaries. In addition, we propose an enhanced big-M method to expedite the computation of the EBCEOR. Finally, the effectiveness of the EBC-EOR formulation, its economic attributes, correlation with the scheduling plan underpinned by model predictive control, and the significant improvement in computational efficiency(over twelvefold) are verified through case studies conducted on two test systems..

关键词： Exact box-constrained economic operating region(EBC-EOR) big-M method intelligent scheduling steady-state adaptive cruise uncertainty renewable energy source

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：