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基于改进YOLOv5的水下目标检测模型

现代计算机 2024年第7期30卷 1-8,63页

作者：张征鑫张笃振江苏师范大学计算机科学与技术学院徐州221116

在复杂的深海环境中,精准地检测和识别目标是海洋探索和保护的关键。此研究对YOLOv5目标检测算法进行了优化,以提升水下目标的检测效果和效率。为了增强模型的特征提取能力,对YOLOv5的关键卷积结构——C3模块进行了替换。此外,引入SEAtt... 详细信息

在复杂的深海环境中,精准地检测和识别目标是海洋探索和保护的关键。此研究对YOLOv5目标检测算法进行了优化,以提升水下目标的检测效果和效率。为了增强模型的特征提取能力,对YOLOv5的关键卷积结构——C3模块进行了替换。此外,引入SEAttention模块,这种模块利用空间注意力机制,使模型更专注于重要目标的识别。评估时,采用EIoU作为标准以准确地衡量目标检测的表现。实验主要在DeepTrash数据集上进行,与原始YOLOv5相比,优化后的模型在精确度上提高了3.1个百分点,召回率提高了1.8个百分点,mAP@0.5提高了2.4个百分点。而且,优化后的模型参数量也减少了17.4个百分点,从而提升了计算效率。即使与最新的YOLOv8相比,优化后的模型也展现出了优越的性能。

关键词：水下目标目标检测注意力机制 YOLOv5 深度学习

数据驱动的闭环控制系统剩余寿命预测方法综述

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中北大学学报（自然科学版） 2024年第1期45卷 1-11页

作者：冯磊张正新李天梅张建勋司小胜火箭军工程大学智剑实验室陕西西安710025

随着先进传感与监测技术的快速发展,数据驱动的设备剩余寿命(RUL)预测技术已成为可靠性和自动化领域的研究前沿,并在设备运维决策中得到广泛应用,提高了设备运行的安全性、可靠性与经济性。关于数据驱动的设备剩余寿命预测方法,多数文... 详细信息

随着先进传感与监测技术的快速发展,数据驱动的设备剩余寿命(RUL)预测技术已成为可靠性和自动化领域的研究前沿,并在设备运维决策中得到广泛应用,提高了设备运行的安全性、可靠性与经济性。关于数据驱动的设备剩余寿命预测方法,多数文献主要聚焦于部件级剩余寿命预测技术,并没有关注闭环控制系统剩余寿命预测技术。不同于部件级的预测,利用数据驱动的方法预测闭环控制系统剩余寿命,需要考虑控制器及反馈控制机制对系统性能退化及剩余寿命预测结果的影响。本文系统综述了数据驱动的闭环控制系统剩余寿命预测及基于预测信息的延寿控制方法的发展动态,剖析了基于Poisson过程的方法、基于Gamma过程的方法、基于Wiener过程的方法和基于混合模型方法的原理、特点与局限性。同时,对于未来数据驱动的闭环控制系统剩余寿命预测及延寿控制,在健康状态表征与综合健康指标构建、多退化部件系统剩余寿命预测及基于预测信息的延寿控制理论和验证应用等方向进行了展望。

关键词：剩余寿命预测闭环控制系统数据驱动退化过程延寿控制

An Age-Dependent and State-Dependent Adaptive Prognostic Approach for Hidden Nonlinear Degrading System

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IEEE/CAA Journal of Automatica Sinica 2022年第5期9卷 907-921页

作者： Zhenan Pang Xiaosheng Si Changhua Hu zhengxin zhang Department of Automation Rocket Force University of EngineeringXi’an 710025China

Remaining useful life(RUL)estimation approaches on the basis of the degradation data have been greatly developed,and significant advances have been *** an applicable degradation model of the system is the foundation and key to accurately estimating its *** current researches focus on age-dependent degradation models,but it has been found that some degradation processes in engineering are also related to the degradation states *** addition,due to different working conditions and complex environments in engineering,the problems of the unit-to-unit variability in the degradation process of the same batch of systems and actual degradation states cannot be directly observed will affect the estimation accuracy of the *** order to solve the above issues jointly,we develop an age-dependent and state-dependent nonlinear degradation model taking into consideration the unit-to-unit variability and hidden degradation ***,the Kalman filter(KF)is utilized to update the hidden degradation states in real time,and the expectation-maximization(EM)algorithm is applied to adaptively estimate the unknown model ***,the approximate analytical RUL distribution can be obtained from the concept of the first hitting *** the new observation is available,the RUL distribution can be updated adaptively on the basis of the updated degradation states and model *** effectiveness and accuracy of the proposed approach are shown by a numerical simulation and case studies for Li-ion batteries and rolling element bearings.

关键词： Expectation-maximization(EM) hidden degradation state Kalman filter(KF) remaining useful life(RUL) unit-to-unit variability.

基于开放数据的城市内涝点空间分布特征及集群识别分析——以昆明市主城区为例

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云南大学学报（自然科学版） 2024年第4期46卷 697-708页

作者：罗兴云赵筱青张正欣罗桑扎西云南大学地球科学学院云南昆明650500 云南大学建筑与规划学院云南昆明650500 江苏省智慧城市设计仿真与可视化技术工程实验室江苏南京210093

以城市内涝点空间分布特征和同质性内涝点集群的识别及其孕灾环境分析为核心,选取昆明市主城区为案例地展开研究.以2020年新闻媒体公布的内涝点信息作为数据源,首先使用核密度和K函数分析内涝点的整体分布和集聚程度;其次,采用HDBSCAN... 详细信息

以城市内涝点空间分布特征和同质性内涝点集群的识别及其孕灾环境分析为核心,选取昆明市主城区为案例地展开研究.以2020年新闻媒体公布的内涝点信息作为数据源,首先使用核密度和K函数分析内涝点的整体分布和集聚程度;其次,采用HDBSCAN空间聚类算法识别昆明市主城区不同类型的内涝点集群,并分析其集群特征;最后,结合孕灾环境数据,以集群为最小研究单元,探讨其孕灾环境的差异性.研究结果显示:①内涝点分布在空间上存在显著的尺度分异,呈现出大离散、小集聚的空间分布模式;②昆明市内涝点可划分为8种类型,每种类型至少有2个集群,最多有4个集群;③不同内涝点集群的孕灾环境存在一定差异,其中地形起伏对内涝点分布的影响最大,即集群范围内地形越崎岖不平,其发生内涝灾害的可能性越大.在城市内涝防治工作中可依据集群空间范围及孕灾特征制定差异化的防治措施,从而科学合理的分配防治力度,提高城市内涝治理工作的科学性及精细度.

关键词：城市内涝空间分布集群特征开放数据昆明

城市滨水公园活力时空特征及影响因素研究——以昆明市为例

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南方建筑 2024年第8期 69-77页

作者：罗桑扎西张正欣杨子江罗兴云云南大学建筑与规划学院云南大学地球科学学院

滨水公园是城市蓝色空间的重要组成部分,其活力的提升对宜居性城市建设具有重要意义。以昆明市24个典型的滨水公园为例,利用手机信令数据分析其不同时段的活力时空特征及影响因素。在已有的研究基础上提出活力峰度和偏度,分析不同时段... 详细信息

滨水公园是城市蓝色空间的重要组成部分,其活力的提升对宜居性城市建设具有重要意义。以昆明市24个典型的滨水公园为例,利用手机信令数据分析其不同时段的活力时空特征及影响因素。在已有的研究基础上提出活力峰度和偏度,分析不同时段滨水公园活力的时空分布特征;从服务、交通、景观三个维度利用地理探测器分析滨水公园的活力驱动因子及其交互作用。结果表明:(1)昆明市滨水公园活力时间分布呈现出“早晚低谷,午后高峰”的特征,活力高峰都出现在下午,但工作日的活力高峰较休息日向后推迟;工作日滨水公园活力集聚明显,高峰突出;休息日则高峰分散,活力较为均衡;在空间上活力值围绕滇池呈现“北高南低,东部聚集”的特征。(2)在活力影响因素方面,滨水公园1000m内各类设施的功能混合度是影响不同时段活力的共性因素,此外,工作日500m的交通路网密度以及公交站点数量的影响较为显著,而在休息日与CBD的距离以及水域面积的影响较为显著;滨水公园活力的受到多维度因子共同作用的影响,景观维度的影响因子与其他维度的影响因子交互作用最显著。基于此为进一步提升昆明市滨水公园活力从功能完善、空间协调、设施配置、景观提升角度提出了优化建议。

关键词：滨水公园活力时空特征影响因素昆明

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高频局放带电指示器设计

现代制造技术与装备 2024年第6期60卷 182-184页

作者：王骅张正昕潘莹王哲斐贺润平国网上海市电力公司市南供电公司上海201199 上海沐芸科技有限公司上海201613

文章首先分析高频局部放电(以下简称局放)的原理,其次探讨高频局放信号的特征和传播与衰减规律,最后阐述高频局放带电指示器的设计,包括总体架构设计、信号处理电路设计和信号处理算法与软件系统开发。所设计的高频局放带电指示器能够... 详细信息

文章首先分析高频局部放电(以下简称局放)的原理,其次探讨高频局放信号的特征和传播与衰减规律,最后阐述高频局放带电指示器的设计,包括总体架构设计、信号处理电路设计和信号处理算法与软件系统开发。所设计的高频局放带电指示器能够实现对设备带电状态的精准监测,可以快速响应设备带电状态的变化,为电力系统的安全监测和故障预警提供了有效手段。

关键词：高频局放带电指示器带电状态监测

A combination of straw incorporation and polymer-coated urea offsets soil ammonia and nitrous oxide emissions in winter wheat fields

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Journal of Integrative Agriculture 2024年第5期23卷 1718-1736页

作者： Xiaoyun Wang Yajie Tian Qianhui zhang zhengxin Zhao Rui Wang Huanjie Cai Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas of Ministry of Education Northwest A&F UniversityYangling712100China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China

The combined effects of straw incorporation(SI)and polymer-coated urea(PCU)application on soil ammonia(NH_(3))and nitrous oxide(N_(2)O)emissions from agricultural fields have not been comprehensively evaluated in Northwest *** conducted a two-year field experiment to assess the effects of combining SI with either uncoated urea(U)or PCU on soil NH_(3)emissions,N_(2)O emissions,winter wheat yields,yield-scaled NH_(3)(/NH_(3)),and yield-scaled N_(2)O(/N_(2)O).Five treatments were investigated,no nitrogen(N)fertilizer(N_(0)),U application at 150 kg N ha-1 with and without SI(SI+U and S_(0)+U),and PCU application at 150 kg N ha^(-1) with and without SI(SI+PCU and S_(0)+PCU).The results showed that the NH_(3);emissions increased by 20.98-34.35%following Sl compared to straw removal,mainly due to increases in soil ammonium(NH_(4)^(+)-N)content and water-flled pore space(WFPS).SI resulted in higher N_(2)O emissions than under the So scenario by 13.31-49.23%due to increases in soil inorganic N(SIN)contents,WFPS,and soil microbial *** contrast,the PCU application reduced the SIN contents compared to the U application,reducing the NH_(3)and N_(2)O emissions by 45.99-58.07 and 18.08-53.04%,***,no significant positive effects of the SI or PCU applications on the winter wheat yield were *** lowest /NH_(3) and /N_(2)O values were observed under the S_(0)+PCU and SI+PCU *** results suggest that single PCU applications and their combination with straw are the optimal agricultural strategies for mitigating gaseous N emissions and maintaining optimal winter wheat yields in Northwest China.

关键词： straw incorporation polymer-coated urea NH_(3)and N_(2)O emissions winter wheat yields

Highly selective photocatalytic reduction of CO_(2) to CH_(4) on electron-rich Fe species cocatalyst under visible light irradiation

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Carbon Energy 2024年第1期6卷 255-266页

作者： Qianying Lin Jiwu Zhao Pu zhang Shuo Wang Ying Wang Zizhong zhang Na Wen zhengxin Ding Rusheng Yuan Xuxu Wang Jinlin Long State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhouChina

Efficient photocatalytic reduction of CO_(2) to high-calorific-value CH4,an ideal target product,is a blueprint for C_(1)industry relevance and carbon neutrality,but it also faces great ***,we demonstrate unprecedented hybrid SiC photocatalysts modified by Fe-based cocatalyst,which are prepared via a facile impregnation-reduction method,featuring an optimized local electronic *** exhibits a superior photocatalytic carbon-based products yield of 30.0μmol g^(−1) h^(−1) and achieves a record CH_(4) selectivity of up to 94.3%,which highlights the effectiveness of electron-rich Fe cocatalyst for boosting photocatalytic performance and ***,the synergistic effects of directional migration of photogenerated electrons and strongπ-back bonding on low-valence Fe effectively strengthen the adsorption and activation of reactants and intermediates in the CO_(2)→CH_(4) *** study inspires an effective strategy for enhancing the multielectron reduction capacity of semiconductor photocatalysts with low-cost Fe instead of noble metals as cocatalysts.

关键词： artificial synthesis of CH_(4) electronic structure optimization Fe species cocatalyst photocatalytic CO_(2) reduction SiC

A novel silver-doped nickel oxide hole-selective contact for crystalline silicon heterojunction solar cells

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Frontiers of Chemical Science and Engineering 2024年第2期18卷 93-101页

作者： Junfeng Zhao Xudong Yang Zhongqing zhang Shengpeng Xie Fangfang Liu Anjun Han zhengxin Liu Yun Sun Wei Liu Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin Engineering Research Center of Thin Film Photoelectronic TechnologyInstitute of Photoelectronic Thin Film Devices and Technology of Nankai University(Ministry of Education)Tianjin 300350China Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 201800China

Based on its band alignment,p-type nickel oxide(NiO_(x))is an excellent candidate material for hole transport layers in crystalline silicon heterojunction solar cells,as it has a smallΔEV and largeΔEC with crystalline ***,to overcome the poor hole selectivity of stoichiometric NiO_(x) due to its low carrier concentration and conductivity,silver-doped nickel oxide(NiO_(x):Ag)hole transport layers with high carrier concentrations were prepared by co-sputtering high-purity silver sheets and pure NiO_(x) *** improved electrical conductivity of NiO_(x) was attributed to the holes generated by the Ag^(+)substituents for Ni^(2+),and moreover,the introduction of Ag^(+)also increased the amount of Ni^(3+)present,both of which increased the carrier concentration in NiO_(x).Ag^(+)doping also reduced the c-Si/NiO_(x) contact resistivity and improved the hole-selective contact with NiO_(x).Furthermore,the problems of particle clusters and interfacial defects on the surfaces of NiO_(x):Ag films were solved by UV-ozone oxidation and high-temperature annealing,which facilitated separation and transport of carriers at the c-Si/NiO_(x) *** constructed c-Si/NiO_(x):Ag solar cell exhibited an increase in open-circuit voltage from 490 to 596 mV and achieved a conversion efficiency of 14.4%.

关键词： band alignment nickel oxide hole transport layer silver-doped nickel oxide UV-ozone