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DAFPN-YOLO: An Improved UAV-Based Object Detection Algorithm Based on YOLOv8s
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作者 Honglin Wang Yaolong Zhang Cheng Zhu 《Computers, Materials & Continua》 2025年第5期1929-1949,共21页
UAV-based object detection is rapidly expanding in both civilian and military applications,including security surveillance,disaster assessment,and border patrol.However,challenges such as small objects,occlusions,comp... UAV-based object detection is rapidly expanding in both civilian and military applications,including security surveillance,disaster assessment,and border patrol.However,challenges such as small objects,occlusions,complex backgrounds,and variable lighting persist due to the unique perspective of UAV imagery.To address these issues,this paper introduces DAFPN-YOLO,an innovative model based on YOLOv8s(You Only Look Once version 8s).Themodel strikes a balance between detection accuracy and speed while reducing parameters,making itwell-suited for multi-object detection tasks from drone perspectives.A key feature of DAFPN-YOLO is the enhanced Drone-AFPN(Adaptive Feature Pyramid Network),which adaptively fuses multi-scale features to optimize feature extraction and enhance spatial and small-object information.To leverage Drone-AFPN’smulti-scale capabilities fully,a dedicated 160×160 small-object detection head was added,significantly boosting detection accuracy for small targets.In the backbone,the C2f_Dual(Cross Stage Partial with Cross-Stage Feature Fusion Dual)module and SPPELAN(Spatial Pyramid Pooling with Enhanced LocalAttentionNetwork)modulewere integrated.These components improve feature extraction and information aggregationwhile reducing parameters and computational complexity,enhancing inference efficiency.Additionally,Shape-IoU(Shape Intersection over Union)is used as the loss function for bounding box regression,enabling more precise shape-based object matching.Experimental results on the VisDrone 2019 dataset demonstrate the effectiveness ofDAFPN-YOLO.Compared to YOLOv8s,the proposedmodel achieves a 5.4 percentage point increase inmAP@0.5,a 3.8 percentage point improvement in mAP@0.5:0.95,and a 17.2%reduction in parameter count.These results highlight DAFPN-YOLO’s advantages in UAV-based object detection,offering valuable insights for applying deep learning to UAV-specific multi-object detection tasks. 展开更多
关键词 YOLOv8 UAV-based object detection AFPN small-object detection head SPPELAN DualConv loss function
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Enhanced Multi-Scale Object Detection Algorithm for Foggy Traffic Scenarios
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作者 Honglin Wang Zitong Shi Cheng Zhu 《Computers, Materials & Continua》 2025年第2期2451-2474,共24页
In foggy traffic scenarios, existing object detection algorithms face challenges such as low detection accuracy, poor robustness, occlusion, missed detections, and false detections. To address this issue, a multi-scal... In foggy traffic scenarios, existing object detection algorithms face challenges such as low detection accuracy, poor robustness, occlusion, missed detections, and false detections. To address this issue, a multi-scale object detection algorithm based on an improved YOLOv8 has been proposed. Firstly, a lightweight attention mechanism, Triplet Attention, is introduced to enhance the algorithm’s ability to extract multi-dimensional and multi-scale features, thereby improving the receptive capability of the feature maps. Secondly, the Diverse Branch Block (DBB) is integrated into the CSP Bottleneck with two Convolutions (C2F) module to strengthen the fusion of semantic information across different layers. Thirdly, a new decoupled detection head is proposed by redesigning the original network head based on the Diverse Branch Block module to improve detection accuracy and reduce missed and false detections. Finally, the Minimum Point Distance based Intersection-over-Union (MPDIoU) is used to replace the original YOLOv8 Complete Intersection-over-Union (CIoU) to accelerate the network’s training convergence. Comparative experiments and dehazing pre-processing tests were conducted on the RTTS and VOC-Fog datasets. Compared to the baseline YOLOv8 model, the improved algorithm achieved mean Average Precision (mAP) improvements of 4.6% and 3.8%, respectively. After defogging pre-processing, the mAP increased by 5.3% and 4.4%, respectively. The experimental results demonstrate that the improved algorithm exhibits high practicality and effectiveness in foggy traffic scenarios. 展开更多
关键词 Deep learning object detection foggy scenes traffic detection YOLOv8
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YOLO-LFD: A Lightweight and Fast Model for Forest Fire Detection
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作者 Honglin Wang Yangyang Zhang Cheng Zhu 《Computers, Materials & Continua》 2025年第2期3399-3417,共19页
Forest fires pose a serious threat to ecological balance, air quality, and the safety of both humans and wildlife. This paper presents an improved model based on You Only Look Once version 5 (YOLOv5), named YOLO Light... Forest fires pose a serious threat to ecological balance, air quality, and the safety of both humans and wildlife. This paper presents an improved model based on You Only Look Once version 5 (YOLOv5), named YOLO Lightweight Fire Detector (YOLO-LFD), to address the limitations of traditional sensor-based fire detection methods in terms of real-time performance and accuracy. The proposed model is designed to enhance inference speed while maintaining high detection accuracy on resource-constrained devices such as drones and embedded systems. Firstly, we introduce Depthwise Separable Convolutions (DSConv) to reduce the complexity of the feature extraction network. Secondly, we design and implement the Lightweight Faster Implementation of Cross Stage Partial (CSP) Bottleneck with 2 Convolutions (C2f-Light) and the CSP Structure with 3 Compact Inverted Blocks (C3CIB) modules to replace the traditional C3 modules. This optimization enhances deep feature extraction and semantic information processing, thereby significantly increasing inference speed. To enhance the detection capability for small fires, the model employs a Normalized Wasserstein Distance (NWD) loss function, which effectively reduces the missed detection rate and improves the accuracy of detecting small fire sources. Experimental results demonstrate that compared to the baseline YOLOv5s model, the YOLO-LFD model not only increases inference speed by 19.3% but also significantly improves the detection accuracy for small fire targets, with only a 1.6% reduction in overall mean average precision (mAP)@0.5. Through these innovative improvements to YOLOv5s, the YOLO-LFD model achieves a balance between speed and accuracy, making it particularly suitable for real-time detection tasks on mobile and embedded devices. 展开更多
关键词 Forest fire detection YOLOv5 LIGHTWEIGHT small object detection
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A Multifunctional Hydrogel with Multimodal Self-Powered Sensing Capability and Stable Direct Current Output for Outdoor Plant Monitoring Systems
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作者 Xinge Guo Luwei Wang +1 位作者 Zhenyang Jin Chengkuo Lee 《Nano-Micro Letters》 2025年第4期1-24,共24页
Smart farming with outdoor monitoring systems is critical to address food shortages and sustainability challenges.These systems facilitate informed decisions that enhance efficiency in broader environmental management... Smart farming with outdoor monitoring systems is critical to address food shortages and sustainability challenges.These systems facilitate informed decisions that enhance efficiency in broader environmental management.Existing outdoor systems equipped with energy harvesters and self-powered sensors often struggle with fluctuating energy sources,low durability under harsh conditions,non-transparent or non-biocompatible materials,and complex structures.Herein,a multifunctional hydrogel is developed,which can fulfill all the above requirements and build selfsustainable outdoor monitoring systems solely by it.It can serve as a stable energy harvester that continuously generates direct current output with an average power density of 1.9 W m^(-3)for nearly 60 days of operation in normal environments(24℃,60%RH),with an energy density of around 1.36×10^(7)J m^(-3).It also shows good self-recoverability in severe environments(45℃,30%RH)in nearly 40 days of continuous operation.Moreover,this hydrogel enables noninvasive and self-powered monitoring of leaf relative water content,providing critical data on evaluating plant health,previously obtainable only through invasive or high-power consumption methods.Its potential extends to acting as other self-powered environmental sensors.This multifunctional hydrogel enables self-sustainable outdoor systems with scalable and low-cost production,paving the way for future agriculture. 展开更多
关键词 Self-powered sensor HYDROGEL Energy harvester Outdoor farming Self-sustainable IoT
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Wood Gasification in Catastrophes: Electricity Production from Light-Duty Vehicles
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作者 Baxter L.M.Williams Henri Croft +8 位作者 James Hunt Josh Viloria Nathan Sherman James Oliver Brody Green Alexey Turchin Juan B.Garcia Martinez Joshua M.Pearce David Denkenberger 《Energy Engineering》 2025年第4期1265-1285,共21页
Following global catastrophic infrastructure loss(GCIL),traditional electricity networks would be damaged and unavailable for energy supply,necessitating alternative solutions to sustain critical services.These altern... Following global catastrophic infrastructure loss(GCIL),traditional electricity networks would be damaged and unavailable for energy supply,necessitating alternative solutions to sustain critical services.These alternative solutions would need to run without damaged infrastructure and would likely need to be located at the point of use,such as decentralized electricity generation from wood gas.This study explores the feasibility of using modified light duty vehicles to self-sustain electricity generation by producing wood chips for wood gasification.A 2004 Ford Falcon Fairmont was modified to power a woodchipper and an electrical generator.The vehicle successfully produced wood chips suitable for gasification with an energy return on investment(EROI)of 3.7 and sustained a stable output of 20 kW electrical power.Scalability analyses suggest such solutions could provide electricity to the critical water sanitation sector,equivalent to 4%of global electricity demand,if production of woodchippers was increased postcatastrophe.Future research could investigate the long-term durability of modified vehicles and alternative electricity generation,and quantify the scalability of wood gasification in GCIL scenarios.This work provides a foundation for developing resilient,decentralized energy systems to ensure the continuity of critical services during catastrophic events,leveraging existing vehicle infrastructure to enhance disaster preparedness. 展开更多
关键词 Global catastrophic infrastructure loss decentralized energy systems wood gasification energy resilience
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Technical and economic feasibility assessment for hybrid energy system electricity and hydrogen generation: A case study
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作者 Paul C.Okonkwo Samuel Chukwujindu Nwokolo +7 位作者 El Manaa Barhoumi Ibrahim B.Mansir Usman Habu Taura Barun Kumar Das Ahmed Bahgat Radwan Wilfred Emori Ephraim Bonah Agyekum Khalid Al Kaaf 《Global Energy Interconnection》 2025年第1期62-81,共20页
Hydrogen is emerging as a promising alternative to fossil fuels in the transportation sector.This study evaluated the feasibility of estab-lishing hydrogen refueling stations in five cities in Oman,Duqm,Haima,Sur,Al B... Hydrogen is emerging as a promising alternative to fossil fuels in the transportation sector.This study evaluated the feasibility of estab-lishing hydrogen refueling stations in five cities in Oman,Duqm,Haima,Sur,Al Buraymi,and Salalah,using Hybrid Optimization of Multiple Electric Renewables(HOMER)software.Three hybrid energy systems,photovoltaic-wind turbine-battery,photovoltaic-battery,and wind turbine-battery were analyzed for each city.Results indicated that Duqm offers the lowest net present cost(NPC),levelized cost of energy,and levelized cost of hydrogen,making it the most cost-effective location.Additionally,Sensitivity analysis showed that as the life of electrolyzer increases during operation,the initial capital expenditure is distributed over a longer operational period,leading to a reduction in the NPC.More so,renewable energy systems produced no emissions which supports Oman’s mission target.This comprehensive analysis confirms the feasibility of establishing a hydrogen refueling station in Duqm,Oman,and highlights advanced optimization techniques’superior capability in designing cost-effective,sustainable energy systems. 展开更多
关键词 CITIES Economic indicator Hydrogen production Optimization SOLAR
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离子液体界面修饰的高效稳定FAPbI_(3)钙钛矿太阳能电池
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作者 Yameen Ahmed 封想想 +8 位作者 高远基 丁洋 龙操玉 Mustafa Haider 李恒月 李专 黄誓成 Makhsud I.Saidaminov 阳军亮 《物理化学学报》 SCIE CAS CSCD 北大核心 2024年第6期34-37,共4页
碘铅甲眯(FAPbI_(3))钙钛矿太阳能电池因其优异的光伏性能而受到广泛关注,但器件的长期稳定性仍然是FAPbI_(3)太阳能电池的关键问题。FAPbI_(3)黑色钙钛矿相在室温下会相变为黄色非钙钛矿相,且水分会加速这一相变。界面工程是提高钙钛... 碘铅甲眯(FAPbI_(3))钙钛矿太阳能电池因其优异的光伏性能而受到广泛关注,但器件的长期稳定性仍然是FAPbI_(3)太阳能电池的关键问题。FAPbI_(3)黑色钙钛矿相在室温下会相变为黄色非钙钛矿相,且水分会加速这一相变。界面工程是提高钙钛矿太阳能电池稳定性的常用方法之一。作为绿色溶剂,离子液体被认为是有毒界面修饰剂的潜在替代品,这也提高了它们的商业可行性,并加速了它们在可再生能源市场的应用。本研究利用具有低挥发性、低毒性、高导电性和高热稳定性的离子液体1-乙基-3-甲基咪唑四氟硼酸盐(EMIM[BF_(4)])来修饰钙钛矿太阳能电池的电子传输层和钙钛矿层之间的界面。离子液体的引入不仅减少了界面缺陷,而且提高了钙钛矿薄膜的质量。密度泛函理论计算表明,离子液体与钙钛矿表面之间存在较强的界面相互作用,有利于降低钙钛矿表面缺陷态密度,稳定钙钛矿晶格。除钙钛矿薄膜缺陷外,溶液处理的SnO_(2)也存在表面缺陷。在SnO_(2)表面的缺陷产生缺陷态,也会导致能带对准问题和稳定性问题。密度泛函理论计算表明,有离子液体的表面间隙态比没有离子液体的表面间隙态小,这种减弱的表面间隙态表明表面区域载流子复合减少,有利于提高器件性能。因此,我们实现了功率转换效率大于22%的离子液体修饰的FAPbI_(3)钙钛矿太阳能电池(对照21%)。在相对湿度~20%的干箱中存放1800h以上后,冠军器件保留了初始状态的~90%,而控制器件降解为非钙钛矿黄色六方相(δ-FAPbI_(3))。 展开更多
关键词 FAPbI_(3) 相稳定性 SnO_(2) 钙钛矿太阳能电池 离子液体 界面工程
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Metaheuristic-Driven Two-Stage Ensemble Deep Learning for Lung/Colon Cancer Classification
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作者 Pouyan Razmjouei Elaheh Moharamkhani +2 位作者 Mohamad Hasanvand Maryam Daneshfar Mohammad Shokouhifar 《Computers, Materials & Continua》 SCIE EI 2024年第9期3855-3880,共26页
This study investigates the application of deep learning,ensemble learning,metaheuristic optimization,and image processing techniques for detecting lung and colon cancers,aiming to enhance treatment efficacy and impro... This study investigates the application of deep learning,ensemble learning,metaheuristic optimization,and image processing techniques for detecting lung and colon cancers,aiming to enhance treatment efficacy and improve survival rates.We introduce a metaheuristic-driven two-stage ensemble deep learning model for efficient lung/colon cancer classification.The diagnosis of lung and colon cancers is attempted using several unique indicators by different versions of deep Convolutional Neural Networks(CNNs)in feature extraction and model constructions,and utilizing the power of various Machine Learning(ML)algorithms for final classification.Specifically,we consider different scenarios consisting of two-class colon cancer,three-class lung cancer,and fiveclass combined lung/colon cancer to conduct feature extraction using four CNNs.These extracted features are then integrated to create a comprehensive feature set.In the next step,the optimization of the feature selection is conducted using a metaheuristic algorithm based on the Electric Eel Foraging Optimization(EEFO).This optimized feature subset is subsequently employed in various ML algorithms to determine the most effective ones through a rigorous evaluation process.The top-performing algorithms are refined using the High-Performance Filter(HPF)and integrated into an ensemble learning framework employing weighted averaging.Our findings indicate that the proposed ensemble learning model significantly surpasses existing methods in classification accuracy across all datasets,achieving accuracies of 99.85%for the two-class,98.70%for the three-class,and 98.96%for the five-class datasets. 展开更多
关键词 Lung cancer colon cancer feature selection electric eel foraging optimization deep learning ensemble learning
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Assistive techniques and their added value for tremor classification in multiple sclerosis
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作者 Nabin Koirala Abdulnasir Hossen +2 位作者 Ioannis U.Isaias Jens Volkmann Muthuraman Muthuraman 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第5期977-978,共2页
Tremor occurs in about half of multiple sclerosis(MS)patients.MS tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tre... Tremor occurs in about half of multiple sclerosis(MS)patients.MS tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tremor may affect the upper and lower extremities,head,and trunk,and may even affect the vocal cords in isolated cases of palatal tremor.MS tremor is classically attributed to lesions of the brain stem,cerebellum,or cerebellar peduncles,and tremor intensity has been shown to correlate with the number of lesions or their functional connections.However,recent work has demonstrated that inflammatory damage to the cerebello-thalamic and cortico-thalamic pathways might also play an important role in causing tremor,as it co-occurs with other signs and symptoms of MS such as dysarthria,dysmetria,dysdiadochokinesia,and dystonia(Alusi et al.,2001). 展开更多
关键词 TREMOR SCLEROSIS
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Performance Evaluation ofMulti-Agent Reinforcement Learning Algorithms
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作者 Abdulghani M.Abdulghani Mokhles M.Abdulghani +1 位作者 Wilbur L.Walters Khalid H.Abed 《Intelligent Automation & Soft Computing》 2024年第2期337-352,共16页
Multi-Agent Reinforcement Learning(MARL)has proven to be successful in cooperative assignments.MARL is used to investigate how autonomous agents with the same interests can connect and act in one team.MARL cooperation... Multi-Agent Reinforcement Learning(MARL)has proven to be successful in cooperative assignments.MARL is used to investigate how autonomous agents with the same interests can connect and act in one team.MARL cooperation scenarios are explored in recreational cooperative augmented reality environments,as well as realworld scenarios in robotics.In this paper,we explore the realm of MARL and its potential applications in cooperative assignments.Our focus is on developing a multi-agent system that can collaborate to attack or defend against enemies and achieve victory withminimal damage.To accomplish this,we utilize the StarCraftMulti-Agent Challenge(SMAC)environment and train four MARL algorithms:Q-learning with Mixtures of Experts(QMIX),Value-DecompositionNetwork(VDN),Multi-agent Proximal PolicyOptimizer(MAPPO),andMulti-Agent Actor Attention Critic(MAA2C).These algorithms allow multiple agents to cooperate in a specific scenario to achieve the targeted mission.Our results show that the QMIX algorithm outperforms the other three algorithms in the attacking scenario,while the VDN algorithm achieves the best results in the defending scenario.Specifically,the VDNalgorithmreaches the highest value of battle wonmean and the lowest value of dead alliesmean.Our research demonstrates the potential forMARL algorithms to be used in real-world applications,such as controllingmultiple robots to provide helpful services or coordinating teams of agents to accomplish tasks that would be impossible for a human to do.The SMAC environment provides a unique opportunity to test and evaluate MARL algorithms in a challenging and dynamic environment,and our results show that these algorithms can be used to achieve victory with minimal damage. 展开更多
关键词 Reinforcement learning RL MULTI-AGENT MARL SMAC VDN QMIX MAPPO
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Design and micromanufacturing technologies of focused piezoelectric ultrasound transducers for biomedical applications
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作者 Xingyu Bai Daixu Wang +5 位作者 Liyun Zhen Meng Cui Jingquan Liu Ning Zhao Chengkuo Lee Bin Yang 《International Journal of Extreme Manufacturing》 CSCD 2024年第6期24-48,共25页
Piezoelectric ultrasonic transducers have shown great potential in biomedical applications due to their high acoustic-to-electric conversion efficiency and large power capacity.The focusing technique enables the trans... Piezoelectric ultrasonic transducers have shown great potential in biomedical applications due to their high acoustic-to-electric conversion efficiency and large power capacity.The focusing technique enables the transducer to produce an extremely narrow beam,greatly improving the resolution and sensitivity.In this work,we summarize the fundamental properties and biological effects of the ultrasound field,aiming to establish a correlation between device design and application.Focusing techniques for piezoelectric transducers are highlighted,including material selection and fabrication methods,which determine the final performance of piezoelectric transducers.Numerous examples,from ultrasound imaging,neuromodulation,tumor ablation to ultrasonic wireless energy transfer,are summarized to highlight the great promise of biomedical applications.Finally,the challenges and opportunities of focused ultrasound transducers are presented.The aim of this review is to bridge the gap between focused ultrasound systems and biomedical applications. 展开更多
关键词 piezoelectric ultrasonic transducers focusing techniques preparation method biomedical applications
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聚类有效性评价综述 被引量:117
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作者 杨燕 靳蕃 KAMEL Mohamed 《计算机应用研究》 CSCD 北大核心 2008年第6期1630-1632,1638,共4页
在聚类分析应用中,迫切需要一种客观公正的质量评价方法来评判聚类结果的有效性。为此,从外部评价法、内部评价法和相对评价法三个方面,归纳综述了常用的聚类有效性评价方法,并讨论了模糊聚类评价法和聚类最佳类别数的自动确定问题。
关键词 聚类 聚类评价 有效性指数
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基于粒子谱分布的无线紫外光通信散射传输特性研究 被引量:5
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作者 宋鹏 蔡媛敏 +3 位作者 耿晓军 郭华 冀汉武 张国青 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2022年第3期970-977,共8页
在非直视无线紫外光通信中,利用大气中的粒子对紫外光进行散射作用来传递信息,非直视紫外光通信在近距离隐蔽通信中有广阔的应用前景。雾霾粒子属于气溶胶范畴,由空气中的灰尘、硫化物、有机碳氢化合物等粒子组成。雾霾粒子的尺度、浓... 在非直视无线紫外光通信中,利用大气中的粒子对紫外光进行散射作用来传递信息,非直视紫外光通信在近距离隐蔽通信中有广阔的应用前景。雾霾粒子属于气溶胶范畴,由空气中的灰尘、硫化物、有机碳氢化合物等粒子组成。雾霾粒子的尺度、浓度、形状等因素均会对无线紫外光散射通信的传输特性产生较大的影响。首先,基于蒙特卡罗方法建立了非直视紫外光多次散射模型,将霾粒子的半径和浓度这两个物理量引入该模型中,通过模拟大量光子在雾霾条件下经多次散射到达接收端的概率,进而仿真分析了系统路径损耗与粒子半径和浓度之间的关系。结果表明,(1)在无线紫外光近距离通信条件下,雾霾浓度越大,路径损耗越小,系统通信性能越好;(2)通信距离大于500 m时,增加雾霾粒子浓度,系统路径损耗总体先减小再增大;(3)在粒子浓度一定情况下,增大粒子半径,路径损耗先减小后增大,且随着通信距离的增大,路径损耗极小值的位置不断向粒子半径小的一侧移动。其次,在模型中引入粒子尺度谱分布的概念,对粒子尺度谱分布进行分割,分别求出不同粒径及其所对应浓度。假定粒子尺度谱分布中不同粒径的粒子依次对光子产生散射作用,对相应光子到达接收端的概率求和,得到光子到达接收端的总概率,进而求得多种粒径的粒子共同存在情况下系统的路径损耗,使仿真模型更加逼近实际大气信道中多种半径雾霾粒子共同存在的事实。最后,搭建实验平台,分别在良好、严重雾霾、极严重雾霾三种不同天气条件下,实验测量了系统路径损耗和通信距离、收发仰角之间的关系,并与考虑粒子尺度谱分布模型中计算得到的路径损耗进行对比,实验数据与仿真结果趋势一致,雾霾天气下的通信质量优于良好天气,收发仰角越大对应的路径损耗也越大。 展开更多
关键词 紫外光 雾霾粒子 粒子谱分布 路径损耗
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实时监测的混合式无线传感器网络多路径路由研究 被引量:2
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作者 杨玺 刘少强 +1 位作者 樊晓平 瞿志华 《计算机应用研究》 CSCD 北大核心 2008年第4期1237-1239,共3页
在考虑节点从环境获取能量的基础上,提出了一种用于实时监测的混合无线传感器网络的多路径路由算法。分析了货运列车脱轨车载式无线监测这类实时监测的混合式无线传感器网络系统的应用需求,在设计路由协议时根据节能和传输延时来选择路... 在考虑节点从环境获取能量的基础上,提出了一种用于实时监测的混合无线传感器网络的多路径路由算法。分析了货运列车脱轨车载式无线监测这类实时监测的混合式无线传感器网络系统的应用需求,在设计路由协议时根据节能和传输延时来选择路由。节点通过环境振动采集能量的同时对其能量水平进行等级划分,将传输的数据划分为不同的优先级,每个节点根据自身的能量水平对不同优先级的数据包采用不同的路由策略。仿真实验表明,该路由算法在满足了网络应用需求的基础上具有节能特性,并缩短了传输延时。 展开更多
关键词 无线传感器网络 能量采集 列车脱轨 数据优先级 传输延时
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水平层状介质中基于DTA的三维电磁波逆散射快速模拟算法 被引量:14
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作者 魏宝君 LIU Q H 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2007年第5期1595-1605,共11页
为提高水平层状介质中三维电磁波散射和逆散射数值模拟的效率,在对角张量近似(DTA)的基础上根据不同回代方式得到了求解积分方程的DTA1和DTA2两种近似.这两种近似可以作为计算积分方程稳定型双共轭梯度快速Fourier变换(BCGS-FFT)算法的... 为提高水平层状介质中三维电磁波散射和逆散射数值模拟的效率,在对角张量近似(DTA)的基础上根据不同回代方式得到了求解积分方程的DTA1和DTA2两种近似.这两种近似可以作为计算积分方程稳定型双共轭梯度快速Fourier变换(BCGS-FFT)算法的初始猜测值和预条件因子,从而形成效率更高的混合DTA-BCGS算法.散射实例说明了DTA2的高精度和混合DTA-BCGS算法尤其是混合DTA2-BCGS算法的高效率.由于DTA2近似程度更高,将DTA2与变型Born迭代反演方法(DBIM)相结合形成了一种对三维异常体进行重构的快速电磁波逆散射技术.文中的逆散射实例说明所开发的逆散射技术对重构水平层状介质中的任意三维异常体是非常有效的. 展开更多
关键词 积分方程 对角张量近似(DTA) 稳定型双共轭梯度 快速FOURIER变换 水平层状介质 逆散射 变型Born迭代方法(DBIM)
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一个可用于机器人定位的映射变换 被引量:1
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作者 唐琎 白涛 +1 位作者 陈玥 杨安平 《控制工程》 CSCD 2005年第S2期103-105,156,共4页
在摄像机以某一角度俯拍地面的情形下,根据透视透影的成像原理,推导了一个从地面各点到摄像机图像间的变换公式,也得到了从摄像机图像中各点到地面的变换公式。只要知道世界坐标系中两个点之间的相对位置及其在摄像机图像的位置,就可以... 在摄像机以某一角度俯拍地面的情形下,根据透视透影的成像原理,推导了一个从地面各点到摄像机图像间的变换公式,也得到了从摄像机图像中各点到地面的变换公式。只要知道世界坐标系中两个点之间的相对位置及其在摄像机图像的位置,就可以得到从摄像机图像到地面坐标系变换关系,这两个变换互为逆变换,它们可以在机器人定位及其他应用过程中发挥重要作用。 展开更多
关键词 图像处理 映射变换 透视投影 机器人定位
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机载真实孔径雷达在中小尺度区域海洋遥感中的应用 被引量:1
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作者 张雪虎 David McLaughlin +3 位作者 Elisabeth M Twarog Mark A Sletten 罗立 晏磊 《遥感技术与应用》 CSCD 2005年第1期127-132,共6页
详细介绍一个适用于中小尺度区域海洋遥感图像采集和科学研究的双极化X波段机载真实孔径雷达。这个真实孔径雷达曾参加1996年度、1997年度和1999年度美国海军实验室主持的切萨皮克湾(ChesapeakeBay)淡水层实地考察实验。实验结果表明应... 详细介绍一个适用于中小尺度区域海洋遥感图像采集和科学研究的双极化X波段机载真实孔径雷达。这个真实孔径雷达曾参加1996年度、1997年度和1999年度美国海军实验室主持的切萨皮克湾(ChesapeakeBay)淡水层实地考察实验。实验结果表明应用民用产品集成的廉价机载实孔径雷达可以成为研究中小型海洋现象,如油层污染,内波和海口淡水层及其边缘等的高性价比的有力遥感工具。文章还探讨了应用于海洋表面遥感的机载真实孔径雷达的系统设计,最优参数和实践中的局限性。 展开更多
关键词 机载雷达 真实孔径雷达 海洋遥感
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层状介质中三维物体重构的对比源反演算法 被引量:1
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作者 魏宝君 LIU Q H 《中国石油大学学报(自然科学版)》 EI CAS CSCD 北大核心 2007年第4期38-45,共8页
对比源反演(CSI)算法将反演问题转化为求解成本泛函的极小值问题,从而形成重构对比源和对比度的迭代序列。开发了一种三维CSI算法对层状介质中的三维物体进行重构,该算法是对二维对比源反演算法的推广。该算法无须正演计算,亦无须人为... 对比源反演(CSI)算法将反演问题转化为求解成本泛函的极小值问题,从而形成重构对比源和对比度的迭代序列。开发了一种三维CSI算法对层状介质中的三维物体进行重构,该算法是对二维对比源反演算法的推广。该算法无须正演计算,亦无须人为地选择正则化参数,反演过程更稳定。CSI的每一次迭代过程均采用快速Fourier变换技术计算并矢Green函数算子及其共轭算子,确保了该算法在三维层状介质情况下的高效率。复杂模型的反演结果说明,CSI算法对重构层状介质中的任意三维异常体是非常有效的。 展开更多
关键词 对比源反演(CSI)算法 层状介质 三维物体重构 并矢Green函数 快速FOURIER变换
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水平层状介质并矢Green函数的递推矩阵方法
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作者 魏宝君 张庚骥 LIU Q H 《大学物理》 北大核心 2008年第6期6-12,共7页
采用递推矩阵方法计算任意数目水平层状介质的并矢Green函数.根据层界面处电场和磁场的连续性条件得到3个确定Sommerfeld积分待定系数的矩阵方程组,分别对应于垂向单位电偶极子产生的TM波、水平方向单位电偶极子产生的TE波和TM波,这些... 采用递推矩阵方法计算任意数目水平层状介质的并矢Green函数.根据层界面处电场和磁场的连续性条件得到3个确定Sommerfeld积分待定系数的矩阵方程组,分别对应于垂向单位电偶极子产生的TM波、水平方向单位电偶极子产生的TE波和TM波,这些方程组均可通过递推方法快速求解.只需改变3个方程组中源项元素的位置,就可以方便地得到当源点和场点在任意层时的并矢Green函数.本文给出的并矢Green函数表达式形式简洁且不含指数增加项,计算时不会出现溢出现象. 展开更多
关键词 并矢Green函数 层状介质 递推矩阵方法 Sommerfeld积分
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Granular Computing for Data Analytics:A Manifesto of Human-Centric Computing 被引量:16
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作者 Witold Pedrycz 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第6期1025-1034,共10页
In the plethora of conceptual and algorithmic developments supporting data analytics and system modeling,humancentric pursuits assume a particular position owing to ways they emphasize and realize interaction between ... In the plethora of conceptual and algorithmic developments supporting data analytics and system modeling,humancentric pursuits assume a particular position owing to ways they emphasize and realize interaction between users and the data.We advocate that the level of abstraction,which can be flexibly adjusted,is conveniently realized through Granular Computing.Granular Computing is concerned with the development and processing information granules–formal entities which facilitate a way of organizing knowledge about the available data and relationships existing there.This study identifies the principles of Granular Computing,shows how information granules are constructed and subsequently used in describing relationships present among the data. 展开更多
关键词 AGGREGATION CLUSTERING design of information granules fuzzy sets granular computing information granules principle of justifiable granularity.
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