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Blind recognition of k/n rate convolutional encoders from noisy observation 被引量:14
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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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Application of Instantaneous Rotational Speed to Detect Gearbox Faults Based on Double Encoders 被引量:2
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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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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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Distantly Supervised Relation Extraction Based On Collaborative Encoders with Hierarchy Relations
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作者 Jianxia Chen Xu Jin +2 位作者 Yu Cheng Chenglin Zhang Maohuan Zhang 《Data Intelligence》 2025年第4期997-1015,共19页
Since extracting structured information with automatic annotation,distantly supervised relation extraction(DSRE)reduces the cost of labor greatly and has become a remarkable approach to relation extraction.However,DSR... Since extracting structured information with automatic annotation,distantly supervised relation extraction(DSRE)reduces the cost of labor greatly and has become a remarkable approach to relation extraction.However,DSRE also produces a lot of mislabeled data in automatic annotation.To address this issue,this paper proposes a novel DSRE model,based on collaborative encoders with hierarchy relation of relations,namely CEH-RORs.In particular,CEH-RORs proposes collaborative encoders,which not only dynamically control the amount of information but also select useful information as effectively as possible.Moreover,this paper constructs the hierarchical graph based on the graph attention network(GAT)to aggregate the node information,in which each relation in the hierarchy of relations forms a node in the input graph.In addition,this paper further improves the performance by using pre-trained relational embeddings.Extensive experiments demonstrate that our approach improved AUC by 4.69%and average P@N to 1.78%compared to its sub-optimal value of existing remarkable models. 展开更多
关键词 Distantly supervised relation extraction Collaborative encoders Hierarchy relations Graph attention network Relational embeddings
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Fast acquisition of high resolution liquid NMR spectroscopy
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作者 Wen Zhu Mengjie Qiu +3 位作者 Yao Luo Xiaoqi Shi Zhong Chen Yanqin Lin 《Magnetic Resonance Letters》 2026年第1期32-42,共11页
Nuclear magnetic resonance(NMR)spectroscopy is a powerful tool for analyzing molecular structure and composition.However,traditional NMR experiments suffer from long acquisition times,especially in multidimensional NM... Nuclear magnetic resonance(NMR)spectroscopy is a powerful tool for analyzing molecular structure and composition.However,traditional NMR experiments suffer from long acquisition times,especially in multidimensional NMR spectroscopy.This problem,to some extent,limits broader applications of NMR techniques.Various methods have been proposed to accelerate sampling,including non-uniform sampling(NUS),multi-FID acquisition(MFA),Hadamard encoding,Fourier encoding,spatial encoding Ultrafast 2D NMR(UF2DNMR),and so on.The review focuses on rapid sampling methods developed in contemporary China,introducing their fundamental principles and applications while discussing their respective advantages and disadvantages. 展开更多
关键词 Nuclear magnetic resonance(NMR) Fast acquisition Non-uniform sampling(NUS) Multi-FID acquisition(MFA) Hadamard encoding Fourier encoding Spatial encoding ultrafast 2D NMR (UF-2DNMR) Spin echo chain sampling Chemical shifts refocusing
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A Fine-Grained RecognitionModel based on Discriminative Region Localization and Efficient Second-Order Feature Encoding
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作者 Xiaorui Zhang Yingying Wang +3 位作者 Wei Sun Shiyu Zhou Haoming Zhang Pengpai Wang 《Computers, Materials & Continua》 2026年第4期946-965,共20页
Discriminative region localization and efficient feature encoding are crucial for fine-grained object recognition.However,existing data augmentation methods struggle to accurately locate discriminative regions in comp... Discriminative region localization and efficient feature encoding are crucial for fine-grained object recognition.However,existing data augmentation methods struggle to accurately locate discriminative regions in complex backgrounds,small target objects,and limited training data,leading to poor recognition.Fine-grained images exhibit“small inter-class differences,”and while second-order feature encoding enhances discrimination,it often requires dual Convolutional Neural Networks(CNN),increasing training time and complexity.This study proposes a model integrating discriminative region localization and efficient second-order feature encoding.By ranking feature map channels via a fully connected layer,it selects high-importance channels to generate an enhanced map,accurately locating discriminative regions.Cropping and erasing augmentations further refine recognition.To improve efficiency,a novel second-order feature encoding module generates an attention map from the fourth convolutional group of Residual Network 50 layers(ResNet-50)and multiplies it with features from the fifth group,producing second-order features while reducing dimensionality and training time.Experiments on Caltech-University of California,San Diego Birds-200-2011(CUB-200-2011),Stanford Car,and Fine-Grained Visual Classification of Aircraft(FGVC Aircraft)datasets show state-of-the-art accuracy of 88.9%,94.7%,and 93.3%,respectively. 展开更多
关键词 Fine-grained recognition feature encoding data augmentation second-order feature discriminative regions
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Near-infrared Spectroscopy Detection of Rice Protein Content Based on Stacking Multi-model Fusion
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作者 Shengye WANG Siting WU +2 位作者 Jinming LIU Chunqi WANG Zhijiang LI 《Agricultural Biotechnology》 2026年第1期42-46,共5页
[Objectives]This study was conducted to achieve rapid and accurate detection of protein content in rice with a particle size of 1.0 mm.[Methods]A multi-model fusion strategy was proposed on the basis of Stacking ensem... [Objectives]This study was conducted to achieve rapid and accurate detection of protein content in rice with a particle size of 1.0 mm.[Methods]A multi-model fusion strategy was proposed on the basis of Stacking ensemble learning.A base learner pool was constructed,containing Partial Least Squares(PLS),Support Vector Machine(SVM),Deep Extreme Learning Machine(DELM),Random Forest(RF),Gradient Boosting Decision Tree(GBDT),and Multilayer Perceptron(MLP).PLS,DELM,and Linear Regression(LR)were used as meta-learner candidates.Employing integer coding technology,systematic dynamic combinations of base learners and meta-learners were generated,resulting in a total of 40 non-repetitive fusion models.The optimal combination was selected through a comprehensive evaluation based on multiple assessment indicators.[Results]The combination"PLS-DELM-MLP-LR"(code 1367)achieved coefficients of determination of 0.9732 and 0.9780 on the validation set and independent test set,respectively,with relative root mean square errors of 2.35%and 2.36%,and residual predictive deviations of 6.1075 and 6.7479,respectively.[Conclusions]The Stacking fusion model significantly enhances the predictive accuracy and robustness of spectral quantitative analysis,providing an efficient and feasible solution for modeling complex agricultural product spectral data. 展开更多
关键词 Rice protein Near-infrared spectroscopy Stacking ensemble learning Multi-model fusion Integer encoding
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Similarities and Differences in Interpreting Multimodal Discourses Between"Decoders"and"Encoders"
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作者 Rui-lan Cheng 《Language and Semiotic Studies》 2018年第1期102-124,共23页
In order to explore the gaps between decoders' interpretations and encoders' designing intentions with respect to the same multimodal discourses, thirty linguistic and thirty art graphic participants were chos... In order to explore the gaps between decoders' interpretations and encoders' designing intentions with respect to the same multimodal discourses, thirty linguistic and thirty art graphic participants were chosen as decoders and encoders, respectively.The participants were required to interpret the same research data in terms of the best and the worst major colors, as well as the best and the worst synergetic patterns formed by major modes.It was found that the complete unanimity in terms of both color and spatial arrangements among the interpretations between participants only reached 43.3%.The unanimity in the interpretations from the perspective of color alone reached 46.7%.Moreover, the interpretations from the perspective of spatial arrangements present high unanimity, with a rate up to 70%.It is concluded that there are both differences and similarities between the interpretations made by encoders and decoders.The possible reasons underlying both differences and similarities are probed in the present study as well. 展开更多
关键词 encoders DECODERS SIMILARITIES DIFFERENCES multimodal discourses
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Ensemble Encoder-Based Attack Traffic Classification for Secure 5G Slicing Networks
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作者 Min-Gyu Kim Hwankuk Kim 《Computer Modeling in Engineering & Sciences》 2025年第5期2391-2415,共25页
This study proposes an efficient traffic classification model to address the growing threat of distributed denial-of-service(DDoS)attacks in 5th generation technology standard(5G)slicing networks.The proposed method u... This study proposes an efficient traffic classification model to address the growing threat of distributed denial-of-service(DDoS)attacks in 5th generation technology standard(5G)slicing networks.The proposed method utilizes an ensemble of encoder components from multiple autoencoders to compress and extract latent representations from high-dimensional traffic data.These representations are then used as input for a support vector machine(SVM)-based metadata classifier,enabling precise detection of attack traffic.This architecture is designed to achieve both high detection accuracy and training efficiency,while adapting flexibly to the diverse service requirements and complexity of 5G network slicing.The model was evaluated using the DDoS Datasets 2022,collected in a simulated 5G slicing environment.Experiments were conducted under both class-balanced and class-imbalanced conditions.In the balanced setting,the model achieved an accuracy of 89.33%,an F1-score of 88.23%,and an Area Under the Curve(AUC)of 89.45%.In the imbalanced setting(attack:normal 7:3),the model maintained strong robustness,=achieving a recall of 100%and an F1-score of 90.91%,demonstrating its effectiveness in diverse real-world scenarios.Compared to existing AI-based detection methods,the proposed model showed higher precision,better handling of class imbalance,and strong generalization performance.Moreover,its modular structure is well-suited for deployment in containerized network function(NF)environments,making it a practical solution for real-world 5G infrastructure.These results highlight the potential of the proposed approach to enhance both the security and operational resilience of 5G slicing networks. 展开更多
关键词 5G slicing networks attack traffic classification ensemble encoders autoencoder AI-based security
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基于机器学习的槽型结构动态变形场重构
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作者 白金川 胡高波 +2 位作者 陈三桂 肖汉林 张涛 《舰船科学技术》 北大核心 2025年第22期38-45,共8页
针对目前多数重构位移场的方法在实际工程应用中存在测点数量多、位置要求高等问题,引入机器学习建立了应变与位移之间的关系,实现了位移场的重构。分析LSTM、Transformer Encoder在动态变形重构中的精度和鲁棒性;然后设计加工槽型结构... 针对目前多数重构位移场的方法在实际工程应用中存在测点数量多、位置要求高等问题,引入机器学习建立了应变与位移之间的关系,实现了位移场的重构。分析LSTM、Transformer Encoder在动态变形重构中的精度和鲁棒性;然后设计加工槽型结构搭建实验平台,对槽道侧壁进行动态加载,通过采集系统和激光位移传感器对应变、位移信息进行采集,对比分析测试集的动态预测结果与传感器的测试结果;最后,融合LSTM和Transformer Encoder这2种神经网络,提出一种新的LSTM-Transformer Encoder(LTE)网络。结果表明:测试集上LSTM网络重构的节点最大平均误差为0.610%,Transformer Encoder重构的节点最大平均相对误差为1.010%。LSTM网络相比Transformer Encoder网络具有更好鲁棒性的同时重构精度更高,提出的LTE网络在测试集上具有更小的MSE(均方误差)及更大的R^(2)(模型拟合系数),在整体的表现上优于LSTM和Transformer Encoder。 展开更多
关键词 结构健康监测 位移场重构 LSTM Transformer Encoder
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基于语义分割的输送带跑偏智能检测方法 被引量:1
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作者 李南雁 廖辉 +3 位作者 赵龙 苏金辉 蓝武生 陈夕松 《科技风》 2025年第3期59-61,共3页
受设备老化与表面受力不均匀的影响,带式输送机易跑偏,导致故障和物料撒落。传统监测方法成本高且安装复杂,为此,本研究提出基于深度学习的智能检测方法,构建皮带线语义分割数据集并标注;使用Unet模型检测皮带线,并通过MiT编码器优化;... 受设备老化与表面受力不均匀的影响,带式输送机易跑偏,导致故障和物料撒落。传统监测方法成本高且安装复杂,为此,本研究提出基于深度学习的智能检测方法,构建皮带线语义分割数据集并标注;使用Unet模型检测皮带线,并通过MiT编码器优化;引入像素位置感知损失强化训练;利用概率霍夫变换提取皮带线的直线位置,定量分析偏移程度。试验结果显示,本模型在皮带线预测上IoU达61.34%,仅占12.93GFlops,具备高效实时性,适用于多种输送带场景。 展开更多
关键词 深度学习 语义分割 MiT Encoder 机器视觉
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基于Transformer编码器和手工特征的航空发动机剩余寿命预测
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作者 陈栋 黄国勇 《机床与液压》 北大核心 2025年第22期54-60,共7页
为了更准确地预测航空涡扇发动机剩余寿命(RUL),充分提取利用不同维度传感器数据之间的相关性和手工筛选特征,提出一种基于多层Transformer编码器(Encoder)和多个手工筛选特征融合的预测模型。利用多层编码器(Encoder)进行特征筛选,利... 为了更准确地预测航空涡扇发动机剩余寿命(RUL),充分提取利用不同维度传感器数据之间的相关性和手工筛选特征,提出一种基于多层Transformer编码器(Encoder)和多个手工筛选特征融合的预测模型。利用多层编码器(Encoder)进行特征筛选,利用编码器多头注意力机制同时处理发动机整个特征序列,提取各维度传感器数据之间的相关性并重新分配权重,使模型能够捕捉到各维度不同特征之间的相互依赖关系;利用模型提取每个特征维度的均值、线性回归趋势系数及传感器数据与真实剩余寿命的协方差3个手工筛选特征,将编码器的输出进行展平和多层全连接处理,然后与手工筛选特征进行拼接,经过全连接层对RUL进行预测。将所提模型在公开数据集C-MAPSS的FD001上进行验证,对比未加入手工筛选特征的模型,文中模型的RMSE降低了18.4%,Score降低了30.3%;对比未对Encoder输入数据进行转置操作的模型,文中模型的RMSE降低了20.8%,Score降低了44.9%,编码器(Encoder)提取了不同维度传感器之间的相关性,通过融合不同手工筛选特征提高了发动机剩余寿命预测准确性。针对相对复杂的数据集FD004,该模型也获得了较好的预测结果,表明所提模型具有较好的稳定性及泛化性。 展开更多
关键词 发动机剩余寿命 编码器(Encoder) 自注意力机制 特征融合
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Joint Feature Encoding and Task Alignment Mechanism for Emotion-Cause Pair Extraction
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作者 Shi Li Didi Sun 《Computers, Materials & Continua》 SCIE EI 2025年第1期1069-1086,共18页
With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant importance.Emotion-cause pair extraction enables the identification of causal relationships between emotions... With the rapid expansion of social media,analyzing emotions and their causes in texts has gained significant importance.Emotion-cause pair extraction enables the identification of causal relationships between emotions and their triggers within a text,facilitating a deeper understanding of expressed sentiments and their underlying reasons.This comprehension is crucial for making informed strategic decisions in various business and societal contexts.However,recent research approaches employing multi-task learning frameworks for modeling often face challenges such as the inability to simultaneouslymodel extracted features and their interactions,or inconsistencies in label prediction between emotion-cause pair extraction and independent assistant tasks like emotion and cause extraction.To address these issues,this study proposes an emotion-cause pair extraction methodology that incorporates joint feature encoding and task alignment mechanisms.The model consists of two primary components:First,joint feature encoding simultaneously generates features for emotion-cause pairs and clauses,enhancing feature interactions between emotion clauses,cause clauses,and emotion-cause pairs.Second,the task alignment technique is applied to reduce the labeling distance between emotion-cause pair extraction and the two assistant tasks,capturing deep semantic information interactions among tasks.The proposed method is evaluated on a Chinese benchmark corpus using 10-fold cross-validation,assessing key performance metrics such as precision,recall,and F1 score.Experimental results demonstrate that the model achieves an F1 score of 76.05%,surpassing the state-of-the-art by 1.03%.The proposed model exhibits significant improvements in emotion-cause pair extraction(ECPE)and cause extraction(CE)compared to existing methods,validating its effectiveness.This research introduces a novel approach based on joint feature encoding and task alignment mechanisms,contributing to advancements in emotion-cause pair extraction.However,the study’s limitation lies in the data sources,potentially restricting the generalizability of the findings. 展开更多
关键词 Emotion-cause pair extraction interactive information enhancement joint feature encoding label consistency task alignment mechanisms
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Dual encoding feature filtering generalized attention UNET for retinal vessel segmentation
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作者 ISLAM Md Tauhidul WU Da-Wen +6 位作者 TANG Qing-Qing ZHAO Kai-Yang YIN Teng LI Yan-Fei SHANG Wen-Yi LIU Jing-Yu ZHANG Hai-Xian 《四川大学学报(自然科学版)》 北大核心 2025年第1期79-95,共17页
Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited t... Retinal blood vessel segmentation is crucial for diagnosing ocular and cardiovascular diseases.Although the introduction of U-Net in 2015 by Olaf Ronneberger significantly advanced this field,yet issues like limited training data,imbalance data distribution,and inadequate feature extraction persist,hindering both the segmentation performance and optimal model generalization.Addressing these critical issues,the DEFFA-Unet is proposed featuring an additional encoder to process domain-invariant pre-processed inputs,thereby improving both richer feature encoding and enhanced model generalization.A feature filtering fusion module is developed to ensure the precise feature filtering and robust hybrid feature fusion.In response to the task-specific need for higher precision where false positives are very costly,traditional skip connections are replaced with the attention-guided feature reconstructing fusion module.Additionally,innovative data augmentation and balancing methods are proposed to counter data scarcity and distribution imbalance,further boosting the robustness and generalization of the model.With a comprehensive suite of evaluation metrics,extensive validations on four benchmark datasets(DRIVE,CHASEDB1,STARE,and HRF)and an SLO dataset(IOSTAR),demonstrate the proposed method’s superiority over both baseline and state-of-the-art models.Particularly the proposed method significantly outperforms the compared methods in cross-validation model generalization. 展开更多
关键词 Vessel segmentation Data balancing Data augmentation Dual encoder Attention Mechanism Model generalization
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基于VMD-MPE和并行双支路的变压器局部放电模式识别方法
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作者 陈康裕 王飞 +1 位作者 曾龙兴 陈尔佳 《电工电能新技术》 北大核心 2025年第9期100-110,共11页
针对变压器局部放电信号的非平稳性和非线性特点,本文提出了一种基于变分模态分解(VMD)和多尺度排列熵(MPE)以及并行双支路的变压器局部放电模式识别方法。首先,利用VMD技术对局部放电波形进行层次分解,分离出若干带限本征模态函数(IMF)... 针对变压器局部放电信号的非平稳性和非线性特点,本文提出了一种基于变分模态分解(VMD)和多尺度排列熵(MPE)以及并行双支路的变压器局部放电模式识别方法。首先,利用VMD技术对局部放电波形进行层次分解,分离出若干带限本征模态函数(IMF),并基于MPE提取各阶IMF分量的深层特征信息,构建特征向量样本集。接着,设计了一个并行双支路模型,其中支路一通过Transformer Encoder的多头注意力机制提取全局特征,支路二利用堆叠的一维卷积神经网络(1D-CNN)结合挤压与激励网络(SENet)进一步提取局部特征信息。通过特征融合拼接策略,将双支路提取的全局与局部特征信息有效融合,从而增强模式识别的表现力。实验结果表明,本文所提出的方法在变压器局部放电模式识别中的准确率达到96.37%,且具有较高的识别效率,能够有效提升变压器局部放电故障的诊断性能,为变压器设备的维护工作提供了坚实的技术保障。 展开更多
关键词 变压器局部放电 变分模态分解 多尺度排列熵 Transformer Encoder 一维卷积神经网络 挤压与激励网络 故障诊断
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Encoding converters for quantum communication networks
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作者 Hua-Xing Xu Shao-Hua Wang +2 位作者 Ya-Qi Song Ping Zhang Chang-Lei Wang 《Chinese Physics B》 2025年第5期64-69,共6页
Quantum communication networks,such as quantum key distribution(QKD)networks,typically employ the measurement-resend mechanism between two users using quantum communication devices based on different quantum encoding ... Quantum communication networks,such as quantum key distribution(QKD)networks,typically employ the measurement-resend mechanism between two users using quantum communication devices based on different quantum encoding types.To achieve direct communication between the devices with different quantum encoding types,in this paper,we propose encoding conversion schemes between the polarization bases(rectilinear,diagonal and circular bases)and the time-bin phase bases(two phase bases and time-bin basis)and design the quantum encoding converters.The theoretical analysis of the encoding conversion schemes is given in detail,and the basis correspondence of encoding conversion and the property of bit flip are revealed.The conversion relationship between polarization bases and time-bin phase bases can be easily selected by controlling a phase shifter.Since no optical switches are used in our scheme,the converter can be operated with high speed.The converters can also be modularized,which may be utilized to realize miniaturization in the future. 展开更多
关键词 quantum communication networks encoding conversion polarization encoding time-bin phase encoding
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Graphene-Metal Hybrid Metasurface for Broadband Terahertz Logic Encoder Induced by Near-Field Coupling
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作者 Yufan Zhang Longhui Zhang +6 位作者 Mingzhu Jiang Chenyue Xi Fangrong Hu Yatao Zhou Shangjun Lin Xinlong Xu Zengxiu Zhao 《Chinese Physics Letters》 2025年第10期101-116,共16页
High-performance terahertz(THz)logic gate devices are crucial components for signal processing and modulation,playing a significant role in the application of THz communication and imaging.Here,we propose a THz broadb... High-performance terahertz(THz)logic gate devices are crucial components for signal processing and modulation,playing a significant role in the application of THz communication and imaging.Here,we propose a THz broadband NOR logic encoder based on a graphene-metal hybrid metasurface.The unit structure consists of two symmetrical dual-gap metal split-ring resonators(DSRRs)arranged in a staggered configuration,with graphene strips embedded in their gaps.The NOR logic gate metadevice is controlled by the bias voltages independently applied to the two electrodes.Experiments show that when the bias voltages are applied to both electrodes,the metadevice achieves the NOR logic gate within a 0.52 THz bandwidth,with an average modulation depth above 80%.The experimental results match well with theoretical simulations.Additionally,the strong near-field coupling induced by the staggered DSRRs causes redshift at both LC resonance and dipole resonance.This phenomenon was demonstrated by coupled mode theory.Besides,we analyze the surface current distribution at resonances and propose four equivalent circuit models to elucidate the physical mechanisms of modulation under distinct loaded voltage conditions.The results not only advance modulation and logic gate designs for THz communication but also demonstrate significant potential applications in 6G networks,THz imaging,and radar systems. 展开更多
关键词 signal processing Broadband terahertz logic encoder Near field coupling thz broadband logic encoder Graphene metal hybrid metasurface bias vo Modulation Terahertz logic gate
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A Blockchain-Based Covert Communication Model Based on Dynamic Base-K Encoding
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作者 Wang Zhujun Zhang Lejun +7 位作者 Li Xueqing Tian Zhihong Su Shen Qiu Jing Chen Huiling Qiu Tie Sergey Gataullin Guo Ran 《China Communications》 2025年第6期319-333,共15页
Blockchain,as a distributed ledger,inherently possesses tamper-resistant capabilities,creating a natural channel for covert communication.However,the immutable nature of data storage might introduce challenges to comm... Blockchain,as a distributed ledger,inherently possesses tamper-resistant capabilities,creating a natural channel for covert communication.However,the immutable nature of data storage might introduce challenges to communication security.This study introduces a blockchain-based covert communication model utilizing dynamic Base-K encoding.The proposed encoding scheme utilizes the input address sequence to determine K to encode the secret message and determines the order of transactions based on K,thus ensuring effective concealment of the message.The dynamic encoding parameters enhance flexibility and address issues related to identical transaction amounts for the same secret message.Experimental results demonstrate that the proposed method maintains smooth communication and low susceptibility to tampering,achieving commendable concealment and embedding rates. 展开更多
关键词 base-K encoding blockchain CONCEALMENT covert communication
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An Auto Encoder-Enhanced Stacked Ensemble for Intrusion Detection in Healthcare Networks
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作者 Fatma S.Alrayes Mohammed Zakariah +2 位作者 Mohammed K.Alzaylaee Syed Umar Amin Zafar Iqbal Khan 《Computers, Materials & Continua》 2025年第11期3457-3484,共28页
Healthcare networks prove to be an urgent issue in terms of intrusion detection due to the critical consequences of cyber threats and the extreme sensitivity of medical information.The proposed Auto-Stack ID in the st... Healthcare networks prove to be an urgent issue in terms of intrusion detection due to the critical consequences of cyber threats and the extreme sensitivity of medical information.The proposed Auto-Stack ID in the study is a stacked ensemble of encoder-enhanced auctions that can be used to improve intrusion detection in healthcare networks.TheWUSTL-EHMS 2020 dataset trains and evaluates themodel,constituting an imbalanced class distribution(87.46% normal traffic and 12.53% intrusion attacks).To address this imbalance,the study balances the effect of training Bias through Stratified K-fold cross-validation(K=5),so that each class is represented similarly on training and validation splits.Second,the Auto-Stack ID method combines many base classifiers such as TabNet,LightGBM,Gaussian Naive Bayes,Histogram-Based Gradient Boosting(HGB),and Logistic Regression.We apply a two-stage training process based on the first stage,where we have base classifiers that predict out-of-fold(OOF)predictions,which we use as inputs for the second-stage meta-learner XGBoost.The meta-learner learns to refine predictions to capture complicated interactions between base models,thus improving detection accuracy without introducing bias,overfitting,or requiring domain knowledge of the meta-data.In addition,the auto-stack ID model got 98.41% accuracy and 93.45%F1 score,better than individual classifiers.It can identify intrusions due to its 90.55% recall and 96.53% precision with minimal false positives.These findings identify its suitability in ensuring healthcare networks’security through ensemble learning.Ongoing efforts will be deployed in real time to improve response to evolving threats. 展开更多
关键词 Intrusion detection auto encoder stacked ensemble WUSTL-EHMS 2020 dataset class imbalance XGBoost
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Image encoding-based bearing fault diagnosis:Review and challenges for high-speed trains
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作者 Huimin Li Lingfeng Li +1 位作者 Bin Liu Ge Xin 《High-Speed Railway》 2025年第3期251-259,共9页
High-Speed Trains (HSTs) have emerged as a mainstream mode of transportation in China, owing to their exceptional safety and efficiency. Ensuring the reliable operation of HSTs is of paramount economic and societal im... High-Speed Trains (HSTs) have emerged as a mainstream mode of transportation in China, owing to their exceptional safety and efficiency. Ensuring the reliable operation of HSTs is of paramount economic and societal importance. As critical rotating mechanical components of the transmission system, bearings make their fault diagnosis a topic of extensive attention. This paper provides a systematic review of image encoding-based bearing fault diagnosis methods tailored to the condition monitoring of HSTs. First, it categorizes the image encoding techniques applied in the field of bearing fault diagnosis. Then, a review of state-of-the-art studies has been presented, encompassing both monomodal image conversion and multimodal image fusion approaches. Finally, it highlights current challenges and proposes future research directions to advance intelligent fault diagnosis in HSTs, aiming to provide a valuable reference for researchers and engineers in the field of intelligent operation and maintenance. 展开更多
关键词 High-speed trains Image encoding Fault diagnosis Rotating machinery Condition monitoring
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