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A Lightweight Network with Dual Encoder and Cross Feature Fusion for Cement Pavement Crack Detection
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作者 Zhong Qu Guoqing Mu Bin Yuan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期255-273,共19页
Automatic crack detection of cement pavement chiefly benefits from the rapid development of deep learning,with convolutional neural networks(CNN)playing an important role in this field.However,as the performance of cr... Automatic crack detection of cement pavement chiefly benefits from the rapid development of deep learning,with convolutional neural networks(CNN)playing an important role in this field.However,as the performance of crack detection in cement pavement improves,the depth and width of the network structure are significantly increased,which necessitates more computing power and storage space.This limitation hampers the practical implementation of crack detection models on various platforms,particularly portable devices like small mobile devices.To solve these problems,we propose a dual-encoder-based network architecture that focuses on extracting more comprehensive fracture feature information and combines cross-fusion modules and coordinated attention mechanisms formore efficient feature fusion.Firstly,we use small channel convolution to construct shallow feature extractionmodule(SFEM)to extract low-level feature information of cracks in cement pavement images,in order to obtainmore information about cracks in the shallowfeatures of images.In addition,we construct large kernel atrous convolution(LKAC)to enhance crack information,which incorporates coordination attention mechanism for non-crack information filtering,and large kernel atrous convolution with different cores,using different receptive fields to extract more detailed edge and context information.Finally,the three-stage feature map outputs from the shallow feature extraction module is cross-fused with the two-stage feature map outputs from the large kernel atrous convolution module,and the shallow feature and detailed edge feature are fully fused to obtain the final crack prediction map.We evaluate our method on three public crack datasets:DeepCrack,CFD,and Crack500.Experimental results on theDeepCrack dataset demonstrate the effectiveness of our proposed method compared to state-of-the-art crack detection methods,which achieves Precision(P)87.2%,Recall(R)87.7%,and F-score(F1)87.4%.Thanks to our lightweight crack detectionmodel,the parameter count of the model in real-world detection scenarios has been significantly reduced to less than 2M.This advancement also facilitates technical support for portable scene detection. 展开更多
关键词 Shallow feature extraction module large kernel atrous convolution dual encoder lightweight network crack detection
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Remaining Useful Life Prediction of Rail Based on Improved Pulse Separable Convolution Enhanced Transformer Encoder
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作者 Zhongmei Wang Min Li +2 位作者 Jing He Jianhua Liu Lin Jia 《Journal of Transportation Technologies》 2024年第2期137-160,共24页
In order to prevent possible casualties and economic loss, it is critical to accurate prediction of the Remaining Useful Life (RUL) in rail prognostics health management. However, the traditional neural networks is di... In order to prevent possible casualties and economic loss, it is critical to accurate prediction of the Remaining Useful Life (RUL) in rail prognostics health management. However, the traditional neural networks is difficult to capture the long-term dependency relationship of the time series in the modeling of the long time series of rail damage, due to the coupling relationship of multi-channel data from multiple sensors. Here, in this paper, a novel RUL prediction model with an enhanced pulse separable convolution is used to solve this issue. Firstly, a coding module based on the improved pulse separable convolutional network is established to effectively model the relationship between the data. To enhance the network, an alternate gradient back propagation method is implemented. And an efficient channel attention (ECA) mechanism is developed for better emphasizing the useful pulse characteristics. Secondly, an optimized Transformer encoder was designed to serve as the backbone of the model. It has the ability to efficiently understand relationship between the data itself and each other at each time step of long time series with a full life cycle. More importantly, the Transformer encoder is improved by integrating pulse maximum pooling to retain more pulse timing characteristics. Finally, based on the characteristics of the front layer, the final predicted RUL value was provided and served as the end-to-end solution. The empirical findings validate the efficacy of the suggested approach in forecasting the rail RUL, surpassing various existing data-driven prognostication techniques. Meanwhile, the proposed method also shows good generalization performance on PHM2012 bearing data set. 展开更多
关键词 Equipment Health Prognostics Remaining Useful Life Prediction Pulse Separable Convolution Attention Mechanism Transformer encoder
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Virus-Encoded MicroRNAs Reveal How Ranavirus Interacts with Amphibian Immune Defense
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作者 Aaron Yang 《Journal of Biomedical Science and Engineering》 2024年第10期179-184,共6页
Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has ... Ranaviruses are harmful viruses that infect amphibians, fish, and reptiles, and have caused particularly devastating declines in amphibian populations. One particular type of ranavirus, called Frog Virus 3 (FV3), has been extensively studied due to its prevalence and impact on amphibians. Previous research has primarily focused on the virus’s genes, but little attention has been given to the non-coding regions of its genome. This article reviews recent studies that reveal the ability of ranaviruses, including FV3, to encode microRNA (miRNA), a type of regulatory RNA. These viral miRNAs play a crucial role in suppressing frog immune genes, modulating the virus-host interaction, and promoting viral infection. Understanding how ranaviruses use miRNAs to control disease progression is essential for addressing the health threat they pose to wildlife and ecosystems. 展开更多
关键词 Ranaviruses AMPHIBIANS Virus-encoded MicroRNA Frog Virus 3 Virus-Host Interaction
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ENCODE计划和功能基因组研究 被引量:5
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作者 丁楠 渠鸿竹 方向东 《遗传》 CAS CSCD 北大核心 2014年第3期237-247,共11页
人类基因组计划完成以来,科学家们一直在努力阐释基因组信息所代表的生物学意义。自2003年开始,美国国家人类基因组研究所(National Human Genome Research Institute,NHGRI)投资近3亿美元启动"DNA元件百科全书(Encyclopedia of DN... 人类基因组计划完成以来,科学家们一直在努力阐释基因组信息所代表的生物学意义。自2003年开始,美国国家人类基因组研究所(National Human Genome Research Institute,NHGRI)投资近3亿美元启动"DNA元件百科全书(Encyclopedia of DNA Elements,ENCODE)"计划,集结了来自美国、中国、英国、日本、西班牙和新加坡等国家的32个实验室的440余名科学家,共同鉴定并分析人类基因组中所有的功能调控元件。高通量测序技术等实验手段的发展和生物信息学技术的不断完善使得ENCODE计划取得了丰硕的成果:确定了甲基化和组蛋白修饰等表观修饰区域及其对染色质结构的作用,进而确定染色质结构的改变影响基因表达;确定了转录因子及其结合位点的信息,并构建了转录因子调控网络;进一步修订更新了假基因和非编码RNA数据库;并确定了调控序列的单核苷酸多态性(Single nucleotide polymorphism,SNP)并与疾病相关联。这些发现一方面有助于系统解析基因和基因组信息、调控元件的调控作用以及非编码区转录调控等分子机制;同时也将为转化医学等生命科学研究领域提供丰富的数据来源。文章综述了高通量测序技术等实验手段的发展和生物信息学技术的不断完善对ENCODE计划的贡献、表观遗传学研究与ENCODE计划的关联性、ENCODE计划的主要科学成果等,同时展望了ENCODE计划对基础医学、临床医学和转化医学等生命科学研究领域的巨大推动作用。 展开更多
关键词 encode 表观遗传学 新一代测序技术 转录调控
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ASP源代码加密程序Script Encoder算法研究 被引量:2
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作者 陈莲娜 《中国计量学院学报》 2001年第3期66-70,共5页
微软为了保护脚本代码的安全性 ,以 COM组件的形式提供了一种对脚本代码进行编码加密的技术 .但其安全性到底如何呢 ?本文将通过“反编译”的方式对其加密。
关键词 ASP SCRIPT encodeR 加密算法 反编译
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一种融合AutoEncoder与CNN的混合算法用于图像特征提取 被引量:19
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作者 刘兴旺 王江晴 徐科 《计算机应用研究》 CSCD 北大核心 2017年第12期3839-3843,3847,共6页
深度学习方法在图像的特征提取方面具有优势。针对传统特征提取方法需要先验知识的不足,提出一种自动编码器(Auto Encoder)与卷积神经网络(convolutional neural network,CNN)相结合的深度学习特征提取方法。该方法给Auto Encoder加入... 深度学习方法在图像的特征提取方面具有优势。针对传统特征提取方法需要先验知识的不足,提出一种自动编码器(Auto Encoder)与卷积神经网络(convolutional neural network,CNN)相结合的深度学习特征提取方法。该方法给Auto Encoder加入快速稀疏性控制,据此对图像训练出基本构件,并初始化CNN的卷积核;同时,给CNN加入了滤波机制,使输出特征保持稀疏性。实验结果表明,在Minist手写数字库和Yale人脸库的识别效果上,提出的特征提取方法均取得了较好的结果,实验进一步通过交叉验证T检验指出,引入滤波机制的特征提取模型优于没有采用滤波机制的模型。 展开更多
关键词 深度学习 卷积神经网络 自动编码器 滤波 稀疏控制
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基于Windows Media Encoder实现流媒体同步控制 被引量:4
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作者 毕野 施珺 《淮海工学院学报(自然科学版)》 CAS 2008年第4期24-27,共4页
基于Windows Media技术的流媒体同步控制需要ASF的支持。现有方法要求直接修改ASF文件的头对象而不易编程实现。通过对比研究,提出了一种基于Windows Media Encoder编码器后处理过程间接修改ASF文件的方法,并探讨了该方法的基本原理。... 基于Windows Media技术的流媒体同步控制需要ASF的支持。现有方法要求直接修改ASF文件的头对象而不易编程实现。通过对比研究,提出了一种基于Windows Media Encoder编码器后处理过程间接修改ASF文件的方法,并探讨了该方法的基本原理。实际系统中的成功应用证明了该方法能有效降低编程难度并易于集成,对实现流媒体同步控制具有一定的参考价值。 展开更多
关键词 流媒体 同步控制 ASF WINDOWS MEDIA Eneoder
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基于ENCODER_ATT机制的远程监督关系抽取
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作者 王健 郑七凡 +1 位作者 李超 石晶 《广西师范大学学报(自然科学版)》 CAS 北大核心 2019年第4期53-60,共8页
在信息抽取中,关系抽取是一项准确识别自然语言中实体间关系的关键技术。针对关系抽取模型中容易丢失关键语义特征问题及远程监督的基本假设容易引入噪声数据的问题,本文提出一种基于远程监督的ENCODER_ATT关系抽取模型。基于循环神经... 在信息抽取中,关系抽取是一项准确识别自然语言中实体间关系的关键技术。针对关系抽取模型中容易丢失关键语义特征问题及远程监督的基本假设容易引入噪声数据的问题,本文提出一种基于远程监督的ENCODER_ATT关系抽取模型。基于循环神经网络构造的ENCODER模型在以词级别进行特征记忆提取,并在句子层面进行语义特征信息整合,保证不遗失关键语义特征的同时去除冗余特征。然后在句子层面引入了注意力机制来降低噪声数据对实验结果的影响。在真实的数据集上进行实验,并绘制准确率-召回率曲线,实验结果表明ENCODER_ATT模型对比同类型的关系抽取方法有明显的提升。 展开更多
关键词 关系抽取 远程监督 encodeR 注意力机制
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基于encoder-decoder框架的城镇污水厂出水水质预测 被引量:1
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作者 史红伟 陈祺 +1 位作者 王云龙 李鹏程 《中国农村水利水电》 北大核心 2023年第11期93-99,共7页
由于污水厂的出水水质指标繁多、污水处理过程中反应复杂、时序非线性程度高,基于机理模型的预测方法无法取得理想效果。针对此问题,提出基于深度学习的污水厂出水水质预测方法,并以吉林省某污水厂监测水质为来源数据,利用多种结合encod... 由于污水厂的出水水质指标繁多、污水处理过程中反应复杂、时序非线性程度高,基于机理模型的预测方法无法取得理想效果。针对此问题,提出基于深度学习的污水厂出水水质预测方法,并以吉林省某污水厂监测水质为来源数据,利用多种结合encoder-decoder结构的神经网络预测水质。结果显示,所提结构对LSTM和GRU网络预测能力都有一定提升,对长期预测能力提升更加显著,ED-GRU模型效果最佳,短期预测中的4个出水水质指标均方根误差(RMSE)为0.7551、0.2197、0.0734、0.3146,拟合优度(R2)为0.9013、0.9332、0.9167、0.9532,可以预测出水质局部变化,而长期预测中的4个指标RMSE为1.7204、1.7689、0.4478、0.8316,R2为0.4849、0.5507、0.4502、0.7595,可以预测出水质变化趋势,与顺序结构相比,短期预测RMSE降低10%以上,R2增加2%以上,长期预测RMSE降低25%以上,R2增加15%以上。研究结果表明,基于encoder-decoder结构的神经网络可以对污水厂出水水质进行准确预测,为污水处理工艺改进提供技术支撑。 展开更多
关键词 污水厂出水 encoder-decoder 多指标水质预测 GRU模型
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基于Auto Encoder的智能监控指纹识别系统
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作者 常峰 贺元骅 《中国测试》 CAS 北大核心 2015年第8期71-74,93,共5页
针对目前已有的嵌入式指纹识别系统往往采用手工提取,不能自动学习并提取识别所需的特征及识别正确率仍然不高的缺点,提出一种基于自动编码器(Auto Encoder)和LSSVM的指纹识别系统。首先,提出采用FPS200作为指纹传感器采集指纹数据,然... 针对目前已有的嵌入式指纹识别系统往往采用手工提取,不能自动学习并提取识别所需的特征及识别正确率仍然不高的缺点,提出一种基于自动编码器(Auto Encoder)和LSSVM的指纹识别系统。首先,提出采用FPS200作为指纹传感器采集指纹数据,然后将采集的数据经过滤波和二值化等预处理,通过比较差异算法获得Auto Encoder中的权值和偏置等参数,从而得到训练好的Auto Encoder用于指纹图像特征提取。最后,将自动提取的特征进行训练和分类,将投票最多的分类作为指纹识别的结果。通过测试表明,系统能较精确地实现指纹识别,具有收敛速度快、正确识别率高和匹配时间短的优点。 展开更多
关键词 指纹 识别率 匹配 自动编码器
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在Flash中基于Adobe Media Encoder组件的视频导入与应用方法
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作者 张佳丽 《电脑知识与技术》 2018年第7Z期215-216,共2页
在flash cs6的默认情况下,Flash cs6只支持flv和f4v格式的视频.如果不是这种格式的视频,我们可以使用Flash cs6自带的视频转换组件Adobe Media Encoder将其他视频格式转换成FLV和F4V格式.本文主要讲解如何使用flash自带的Adobe Media En... 在flash cs6的默认情况下,Flash cs6只支持flv和f4v格式的视频.如果不是这种格式的视频,我们可以使用Flash cs6自带的视频转换组件Adobe Media Encoder将其他视频格式转换成FLV和F4V格式.本文主要讲解如何使用flash自带的Adobe Media Encoder组件进行视频文件的转换,导入和使用. 展开更多
关键词 FLASH ADOBE MEDIA encoder组件 视频
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基于时空特征融合的Encoder-Decoder多步4D短期航迹预测
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作者 石庆研 张泽中 韩萍 《信号处理》 CSCD 北大核心 2023年第11期2037-2048,共12页
航迹预测在确保空中交通安全、高效运行中扮演着至关重要的角色。所预测的航迹信息是航迹优化、冲突告警等决策工具的输入,而预测准确性取决于模型对航迹序列特征的提取能力。航迹序列数据是具有丰富时空特征的多维时间序列,其中每个变... 航迹预测在确保空中交通安全、高效运行中扮演着至关重要的角色。所预测的航迹信息是航迹优化、冲突告警等决策工具的输入,而预测准确性取决于模型对航迹序列特征的提取能力。航迹序列数据是具有丰富时空特征的多维时间序列,其中每个变量都呈现出长短期的时间变化模式,并且这些变量之间还存在着相互依赖的空间信息。为了充分提取这种时空特征,本文提出了基于融合时空特征的编码器-解码器(Spatio-Temporal EncoderDecoder,STED)航迹预测模型。在Encoder中使用门控循环单元(Gated Recurrent Unit,GRU)、卷积神经网络(Convolutional Neural Network,CNN)和注意力机制(Attention,AT)构成的双通道网络来分别提取航迹时空特征,Decoder对时空特征进行拼接融合,并利用GRU对融合特征进行学习和递归输出,实现对未来多步航迹信息的预测。利用真实的航迹数据对算法性能进行验证,实验结果表明,所提STED网络模型能够在未来10 min预测范围内进行高精度的短期航迹预测,相比于LSTM、CNN-LSTM和AT-LSTM等数据驱动航迹预测模型具有更高的精度。此外,STED网络模型预测一个航迹点平均耗时为0.002 s,具有良好的实时性。 展开更多
关键词 4D航迹预测 时空特征 encoder-Decoder 门控循环单元
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Blind recognition of k/n rate convolutional encoders from noisy observation 被引量:13
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作者 Li Huang Wengu Chen +1 位作者 Enhong Chen Hong Chen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第2期235-243,共9页
Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context. This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noi... Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context. This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noisy context based on Walsh-Hadamard transformation and block matrix (WHT-BM). The proposed algorithm constructs a system of noisy linear equations and utilizes all its coefficients to recover parity check matrix. It is able to make use of fault-tolerant feature of WHT, thus providing more accurate results and achieving better error performance in high raw bit error rate (BER) regions. Moreover, it is more computationally efficient with the use of the block matrix (BM) method. © 2017 Beijing Institute of Aerospace Information. 展开更多
关键词 Cognitive radio CONVOLUTION Convolutional codes Error correction Hadamard matrices Hadamard transforms Linear transformations Mathematical transformations Matrix algebra Signal encoding
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基于AutoEncoder的油气管道控制系统异常状态监测方法 被引量:6
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作者 梁凤勤 高媛 +3 位作者 刘功银 黄建国 周权 盛瀚民 《电子测量与仪器学报》 CSCD 北大核心 2019年第12期10-18,共9页
压缩机控制电路的健康状态管理在管道运输中至关重要。通常油气管道压缩机系统部署地点远离城市,环境恶劣,且负荷高、工作时间长,因此故障频发。构建可靠的健康状态检测模型通常需要大量的故障样本,然而在实际数据中,故障样本相对稀缺... 压缩机控制电路的健康状态管理在管道运输中至关重要。通常油气管道压缩机系统部署地点远离城市,环境恶劣,且负荷高、工作时间长,因此故障频发。构建可靠的健康状态检测模型通常需要大量的故障样本,然而在实际数据中,故障样本相对稀缺。采用一种基于自编码器(auto encoder,AE)的单分类方法对油气管道控制系统的异常状态进行辨识。该模型仅需对系统的正常工作状态进行学习,通过编码器可实现特征的自适应提取,从而对数据进行抽象表示,并获得较好的非线性映射能力;当数据分布异常时,系统可区分其与正常信号间的差异,并进行预警。实验部分采用西部输油管道控制系统中实地获取的通信解码信号以及电源信号进行验证,并以单分类支持向量机方法作对比实验,表明了所提出方法的有效性。 展开更多
关键词 故障预警 故障诊断和健康管理 单分类学习 自编码器 深度学习
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基于Encoder-CNN的土壤氮含量光谱预测模型研究 被引量:2
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作者 冀荣华 赵迎迎 +1 位作者 李民赞 郑立华 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2022年第5期1372-1377,共6页
基于光谱的土壤氮含量预测模型泛化能力弱是制约其推广应用的瓶颈。鉴于特征提取及非线性表达能力方面的优势,深度学习模型具有较强的泛化能力。提出一种融合自动编码器和卷积神经网络(Encoder-CNN)的土壤氮含量光谱预测模型,探索模型... 基于光谱的土壤氮含量预测模型泛化能力弱是制约其推广应用的瓶颈。鉴于特征提取及非线性表达能力方面的优势,深度学习模型具有较强的泛化能力。提出一种融合自动编码器和卷积神经网络(Encoder-CNN)的土壤氮含量光谱预测模型,探索模型结构和参数对模型性能的影响。根据以往研究成果和相关性分析,获得180个与氮含量强相关的波长,将其作为Encoder-CNN模型输入,而将土壤氮含量作为模型输出。Encoder-CNN模型利用自动编码器的编码部分进行光谱数据降维,然后输入到卷积神经网络进行土壤氮含量预测。设计2种网络结构,每种网络结构包含2种不同参数设置,共4个模型,用以探索Encoder-CNN土壤氮含量光谱预测模型结构和参数对模型性能的影响。利用公开数据集LUCAS对模型进行训练。按3σ原则对公开数据集LUCAS进行异常值检测与处理,获得20791个数据,其中18711个样本作为训练集,2080个样本作为测试集,对Encoder-CNN模型进行训练。结果表明:对于自动编码器,在相同隐含层数下,最后的隐含层神经元个数为30时,复现效果最优。增加隐含层数,会提升复现效果。增加卷积核数量,特别是尺寸为1×1卷积核,能够提高模型的预测性能与可靠性。增加池化层的网络结构,模型预测精度提升至0.90以上。增加全连接层神经元数量也会提升模型性能。利用自采集的黑龙江黑土实时光谱数据集进行模型迁移,观察模型泛化能力。当模型迭代100次后,在黑龙江数据集上的预测精度即可达到0.90以上;当迭代次数为900时,模型在训练集和测试集上的预测精度可以达到0.98。结果表明,所构建的Encoder-CNN土壤氮含量光谱预测模型具有较好的泛化能力。 展开更多
关键词 土壤 氮含量 光谱预测 卷积神经网络 自动编码器
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Upconversion Nanoparticles-Encoded Hydrogel Microbeads-Based Multiplexed Protein Detection 被引量:4
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作者 Swati Shikha Xiang Zheng Yong Zhang 《Nano-Micro Letters》 SCIE EI CAS 2018年第2期135-150,共16页
Fluorescently encoded microbeads are in demand for multiplexed applications in different fields.Compared to organic dye-based commercially available Luminex's x MAP technology, upconversion nanoparticles(UCNPs) ar... Fluorescently encoded microbeads are in demand for multiplexed applications in different fields.Compared to organic dye-based commercially available Luminex's x MAP technology, upconversion nanoparticles(UCNPs) are better alternatives due to their large antiStokes shift, photostability, nil background, and single wavelength excitation. Here, we developed a new multiplexed detection system using UCNPs for encoding poly(ethylene glycol) diacrylate(PEGDA) microbeads as well as for labeling reporter antibody. However, to prepare UCNPs-encoded microbeads, currently used swellingbased encapsulation leads to non-uniformity, which is undesirable for fluorescence-based multiplexing. Hence,we utilized droplet microfluidics to obtain encoded microbeads of uniform size, shape, and UCNPs distribution inside. Additionally, PEGDA microbeads lack functionality for probe antibodies conjugation on their surface.Methods to functionalize the surface of PEGDA microbeads(acrylic acid incorporation, polydopamine coating)reported thus far quench the fluorescence of UCNPs. Here,PEGDA microbeads surface was coated with silica followed by carboxyl modification without compromising the fluorescence intensity of UCNPs. In this study, droplet microfluidics-assisted UCNPs-encoded microbeads of uniform shape, size, and fluorescence were prepared.Multiple color codes were generated by mixing UCNPs emitting red and green colors at different ratios prior to encapsulation. UCNPs emitting blue color were used to label the reporter antibody. Probe antibodies were covalently immobilized on red UCNPs-encoded microbeads for specific capture of human serum albumin(HSA) as a model protein. The system was also demonstrated for multiplexed detection of both human C-reactive protein(hCRP) and HSA protein by immobilizing anti-h CRP antibodies on green UCNPs. 展开更多
关键词 Upconversion nanoparticles PEGDA microbeads encodING Multiplexed bio-detection Single wavelength excitation
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A correction method of encoder bias in satellite laser ranging system 被引量:3
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作者 Wang Peiyuan Zhu Wei +1 位作者 Zou Tong Guo Tangyong 《Geodesy and Geodynamics》 2013年第3期61-64,共4页
In a satellite laser ranging telescope system, well-aligned encoders of the elevation and azimuth axes are essential for tracking objects. However, it is very difficult and time-consuming to correct the bias between t... In a satellite laser ranging telescope system, well-aligned encoders of the elevation and azimuth axes are essential for tracking objects. However, it is very difficult and time-consuming to correct the bias between the absolute-position indices of the encoders and the astronomical coordinates, especially in the absence of a finder scope for our system. To solve this problem, a method is presented based on the phenomenon that all stars move anti-clockwise around Polaris in the northern hemisphere. Tests of the proposed adjustment procedure in a satellite laser ranging (SLR)system demonstrated the effectiveness and the time saved by using the approach, which greatly facilitates the optimization of a trackin~ svstem. 展开更多
关键词 CORRECTION encoder index TELESCOPE satellite laser ranging
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Determination of optimal period of absolute encoders with single track cyclic gray code 被引量:1
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作者 张帆 朱衡君 《Journal of Central South University》 SCIE EI CAS 2008年第S2期362-366,共5页
Low cost and miniaturized rotary encoders are important in automatic and precise production. Presented here is a code called Single Track Cyclic Gray Code (STCGC) that is an image etched on a single circular track of ... Low cost and miniaturized rotary encoders are important in automatic and precise production. Presented here is a code called Single Track Cyclic Gray Code (STCGC) that is an image etched on a single circular track of a rotary encoder disk read by a group of even spread reading heads to provide a unique codeword for every angular position and features such that every two adjacent words differ in exactly one component, thus avoiding coarse error. The existing construction or combination methods are helpful but not sufficient in determining the period of the STCGC of large word length and the theoretical approach needs further development to extend the word length. Three principles, such as the seed combination, short code removal and ergodicity examination were put forward that suffice determination of the optimal period for such absolute rotary encoders using STCGC with even spread heads. The optimal periods of STCGC in 3 through 29 bit length were determined and listed. 展开更多
关键词 ROTARY encodeR ABSOLUTE encodeR single track GREY code CYCLIC reliability
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基于Encoder-Decoder注意力网络的异常驾驶行为在线识别方法 被引量:2
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作者 唐坤 戴语琴 +2 位作者 徐永能 郭唐仪 邵飞 《兵器装备工程学报》 CAS CSCD 北大核心 2023年第8期63-71,共9页
异常驾驶行为是车辆安全运行的重大威胁,其对人员与物资的安全高效投送造成严重危害。以低成本非接触式的手机多传感器数据为基础,通过对驾驶行为特性进行数据分析,提出一种融合Encoder-Decoder深度网络与Attention机制的异常驾驶行为... 异常驾驶行为是车辆安全运行的重大威胁,其对人员与物资的安全高效投送造成严重危害。以低成本非接触式的手机多传感器数据为基础,通过对驾驶行为特性进行数据分析,提出一种融合Encoder-Decoder深度网络与Attention机制的异常驾驶行为的在线识别方法。该方法由基于LSTM(long short-term memory)的Encoder-Decoder、Attention机制与基于SVM(support vector machine)的分类器3个模块构成。该系统识别方法包括:输入编码、注意力学习、特征解码、序列重构、残差计算与驾驶行为分类等6个步骤。该技术方法利用自然驾驶条件下所采集的手机传感器数据进行实验。实验结果表明:①手机多传感器数据融合方法对驾驶行为识别具备有效性;②异常驾驶行为必然会造成数据异常波动;③Attention机制有助于提升模型学习效果,对所提出模型的识别准确率F1-score为0.717,与经典同类模型比较,准确率得到显著提升;④对于汽车异常驾驶行为来说,SVM比Logistic与随机森林算法具有更优越的识别效果。 展开更多
关键词 异常驾驶 深度学习 编码器-解码器 长短时记忆网络 注意力机制
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Application of Instantaneous Rotational Speed to Detect Gearbox Faults Based on Double Encoders 被引量:1
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作者 Lin Liang Fei Liu +2 位作者 Xiangwei Kong Maolin Li Guanghua Xu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2019年第1期54-64,共11页
Considerable studies have been carried out on fault diagnosis of gears, with most of them concentrated on conventional vibration analysis. However, besides the complexity of gear dynamics, the diagnosis results in ter... Considerable studies have been carried out on fault diagnosis of gears, with most of them concentrated on conventional vibration analysis. However, besides the complexity of gear dynamics, the diagnosis results in terms of vibration signal are easily misjudged owing to the interference of sensor position or other components. In this paper, an alternative gearbox fault detection method based on the instantaneous rotational speed is proposed because of its advantages over vibration analysis. Depending on the timer/counter-based method for the pulse signal of the optical encoder, the varying rotational speed can be obtained e ectively. Owing to the coupling and meshing of gears in transmission, the excitations are the same for the instantaneous rotational speed of the input and output shafts. Thus, the di erential signal of instantaneous rotational speeds can be adopted to eliminate the e ect of the interference excitations and extract the associated feature of the localized fault e ectively. With the experiments on multistage gearbox test system, the di erential signal of instantaneous speeds is compared with other signals. It is proved that localized faults in the gearbox generate small angular speed fluctuations, which are measurable with an optical encoder. Using the di erential signal of instantaneous speeds, the fault characteristics are extracted in the spectrum where the deterministic frequency component and its harmonics corresponding to crack fault characteristics are displayed clearly. 展开更多
关键词 Instantaneous ROTATIONAL speed Optical encodeR Localized fault MULTISTAGE GEARBOX
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