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Optimizing BERT for Bengali Emotion Classification: Evaluating Knowledge Distillation, Pruning, and Quantization
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作者 Md Hasibur Rahman Mohammed Arif Uddin +1 位作者 Zinnat Fowzia Ria Rashedur M.Rahman 《Computer Modeling in Engineering & Sciences》 2025年第2期1637-1666,共30页
The rapid growth of digital data necessitates advanced natural language processing(NLP)models like BERT(Bidi-rectional Encoder Representations from Transformers),known for its superior performance in text classificati... The rapid growth of digital data necessitates advanced natural language processing(NLP)models like BERT(Bidi-rectional Encoder Representations from Transformers),known for its superior performance in text classification.However,BERT’s size and computational demands limit its practicality,especially in resource-constrained settings.This research compresses the BERT base model for Bengali emotion classification through knowledge distillation(KD),pruning,and quantization techniques.Despite Bengali being the sixth most spoken language globally,NLP research in this area is limited.Our approach addresses this gap by creating an efficient BERT-based model for Bengali text.We have explored 20 combinations for KD,quantization,and pruning,resulting in improved speedup,fewer parameters,and reduced memory size.Our best results demonstrate significant improvements in both speed and efficiency.For instance,in the case of mBERT,we achieved a 3.87×speedup and 4×compression ratio with a combination of Distil+Prune+Quant that reduced parameters from 178 to 46 M,while the memory size decreased from 711 to 178 MB.These results offer scalable solutions for NLP tasks in various languages and advance the field of model compression,making these models suitable for real-world applications in resource-limited environments. 展开更多
关键词 Bengali NLP black-box distillation emotion classification model compression post-training quantization unstructured pruning
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Activation Redistribution Based Hybrid Asymmetric Quantization Method of Neural Networks 被引量:1
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作者 Lu Wei Zhong Ma Chaojie Yang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期981-1000,共20页
The demand for adopting neural networks in resource-constrained embedded devices is continuously increasing.Quantization is one of the most promising solutions to reduce computational cost and memory storage on embedd... The demand for adopting neural networks in resource-constrained embedded devices is continuously increasing.Quantization is one of the most promising solutions to reduce computational cost and memory storage on embedded devices.In order to reduce the complexity and overhead of deploying neural networks on Integeronly hardware,most current quantization methods use a symmetric quantization mapping strategy to quantize a floating-point neural network into an integer network.However,although symmetric quantization has the advantage of easier implementation,it is sub-optimal for cases where the range could be skewed and not symmetric.This often comes at the cost of lower accuracy.This paper proposed an activation redistribution-based hybrid asymmetric quantizationmethod for neural networks.The proposedmethod takes data distribution into consideration and can resolve the contradiction between the quantization accuracy and the ease of implementation,balance the trade-off between clipping range and quantization resolution,and thus improve the accuracy of the quantized neural network.The experimental results indicate that the accuracy of the proposed method is 2.02%and 5.52%higher than the traditional symmetric quantization method for classification and detection tasks,respectively.The proposed method paves the way for computationally intensive neural network models to be deployed on devices with limited computing resources.Codes will be available on https://github.com/ycjcy/Hybrid-Asymmetric-Quantization. 展开更多
关键词 quantization neural network hybrid asymmetric ACCURACY
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Landau quantization effects on damping Kawahara solitons in electron–positron–ion plasma in rotating ionized medium
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作者 E I El-Awady S Hussain N Akhtar 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第10期141-150,共10页
For the dynamics of three-dimensional electron–positron–ion plasmas,a fluid quantum hydrodynamic model is proposed by considering Landau quantization effects in dense plasma.Ion–neutral collisions in the presence o... For the dynamics of three-dimensional electron–positron–ion plasmas,a fluid quantum hydrodynamic model is proposed by considering Landau quantization effects in dense plasma.Ion–neutral collisions in the presence of the Coriolis force are also considered.The application of the reductive perturbation technique produces a wave evolution equation represented by a damped Korteweg–de Vries equation.This equation,however,is insufficient for describing waves in our system at very low dispersion coefficients.As a result,we considered the highest-order perturbation,which resulted in the damped Kawahara equation.The effects of the magnetic field,Landau quantization,the ratio of positron density to electron density,the ratio of positron density to ion density,and the direction cosine on linear dispersion laws as well as soliton and conoidal solutions of the damped Kawahara equation are explored.The understanding from this research can contribute to the broader field of astrophysics and aid in the interpretation of observational data from white dwarfs. 展开更多
关键词 Kawahara equation solitary and cnoidal waves quantum plasma magnetoplasmas Landau quantization Coriolis force
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In situ calibrated angle between the quantization axis and the propagating direction of the light field for trapping neutral atoms
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作者 郭瑞军 何晓东 +7 位作者 盛诚 王坤鹏 许鹏 刘敏 王谨 孙晓红 曾勇 詹明生 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期318-323,共6页
The recently developed magic-intensity trapping technique of neutral atoms efficiently mitigates the detrimental effect of light shifts on atomic qubits and substantially enhances the coherence time. This technique re... The recently developed magic-intensity trapping technique of neutral atoms efficiently mitigates the detrimental effect of light shifts on atomic qubits and substantially enhances the coherence time. This technique relies on applying a bias magnetic field precisely parallel to the wave vector of a circularly polarized trapping laser field. However, due to the presence of the vector light shift experienced by the trapped atoms, it is challenging to precisely define a parallel magnetic field, especially at a low bias magnetic field strength, for the magic-intensity trapping of85Rb qubits. In this work, we present a method to calibrate the angle between the bias magnetic field and the trapping laser field with the compensating magnetic fields in the other two directions orthogonal to the bias magnetic field direction. Experimentally, with a constantdepth trap and a fixed bias magnetic field, we measure the respective resonant frequencies of the atomic qubits in a linearly polarized trap and a circularly polarized one via the conventional microwave Rabi spectra with different compensating magnetic fields and obtain the corresponding total magnetic fields via the respective resonant frequencies using the Breit–Rabi formula. With known total magnetic fields, the angle is a function of the other two compensating magnetic fields.Finally, the projection value of the angle on either of the directions orthogonal to the bias magnetic field direction can be reduced to 0(4)° by applying specific compensating magnetic fields. The measurement error is mainly attributed to the fluctuation of atomic temperature. Moreover, it also demonstrates that, even for a small angle, the effect is strong enough to cause large decoherence of Rabi oscillation in a magic-intensity trap. Although the compensation method demonstrated here is explored for the magic-intensity trapping technique, it can be applied to a variety of similar precision measurements with trapped neutral atoms. 展开更多
关键词 quantization axis trapping laser ANGLE compensating magnetic fields
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Network-Assisted Full-Duplex Cell-Free mmWave Massive MIMO Systems with DAC Quantization and Fronthaul Compression
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作者 Li Jiamin Fan Qingrui +4 位作者 Zhang Yu Zhu Pengcheng Wang Dongming Wu Hao You Xiaohu 《China Communications》 SCIE CSCD 2024年第11期75-87,共13页
In this paper,we investigate networkassisted full-duplex(NAFD)cell-free millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems with digital-to-analog converter(DAC)quantization and fronthaul compre... In this paper,we investigate networkassisted full-duplex(NAFD)cell-free millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)systems with digital-to-analog converter(DAC)quantization and fronthaul compression.We propose to maximize the weighted uplink and downlink sum rate by jointly optimizing the power allocation of both the transmitting remote antenna units(T-RAUs)and uplink users and the variances of the downlink and uplink fronthaul compression noises.To deal with this challenging problem,we further apply a successive convex approximation(SCA)method to handle the non-convex bidirectional limited-capacity fronthaul constraints.The simulation results verify the convergence of the proposed SCA-based algorithm and analyze the impact of fronthaul capacity and DAC quantization on the spectral efficiency of the NAFD cell-free mmWave massive MIMO systems.Moreover,some insightful conclusions are obtained through the comparisons of spectral efficiency,which shows that NAFD achieves better performance gains than cotime co-frequency full-duplex cloud radio access network(CCFD C-RAN)in the cases of practical limited-resolution DACs.Specifically,their performance gaps with 8-bit DAC quantization are larger than that with1-bit DAC quantization,which attains a 5.5-fold improvement. 展开更多
关键词 cell-free massive MIMO DAC quantization millimeter-wave network-assisted full-duplex
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Learning Vector Quantization-Based Fuzzy Rules Oversampling Method
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作者 Jiqiang Chen Ranran Han +1 位作者 Dongqing Zhang Litao Ma 《Computers, Materials & Continua》 SCIE EI 2024年第6期5067-5082,共16页
Imbalanced datasets are common in practical applications,and oversampling methods using fuzzy rules have been shown to enhance the classification performance of imbalanced data by taking into account the relationship ... Imbalanced datasets are common in practical applications,and oversampling methods using fuzzy rules have been shown to enhance the classification performance of imbalanced data by taking into account the relationship between data attributes.However,the creation of fuzzy rules typically depends on expert knowledge,which may not fully leverage the label information in training data and may be subjective.To address this issue,a novel fuzzy rule oversampling approach is developed based on the learning vector quantization(LVQ)algorithm.In this method,the label information of the training data is utilized to determine the antecedent part of If-Then fuzzy rules by dynamically dividing attribute intervals using LVQ.Subsequently,fuzzy rules are generated and adjusted to calculate rule weights.The number of new samples to be synthesized for each rule is then computed,and samples from the minority class are synthesized based on the newly generated fuzzy rules.This results in the establishment of a fuzzy rule oversampling method based on LVQ.To evaluate the effectiveness of this method,comparative experiments are conducted on 12 publicly available imbalance datasets with five other sampling techniques in combination with the support function machine.The experimental results demonstrate that the proposed method can significantly enhance the classification algorithm across seven performance indicators,including a boost of 2.15%to 12.34%in Accuracy,6.11%to 27.06%in G-mean,and 4.69%to 18.78%in AUC.These show that the proposed method is capable of more efficiently improving the classification performance of imbalanced data. 展开更多
关键词 OVERSAMPLING fuzzy rules learning vector quantization imbalanced data support function machine
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Reinforcement Learning Based Quantization Strategy Optimal Assignment Algorithm for Mixed Precision
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作者 Yuejiao Wang Zhong Ma +2 位作者 Chaojie Yang Yu Yang Lu Wei 《Computers, Materials & Continua》 SCIE EI 2024年第4期819-836,共18页
The quantization algorithm compresses the original network by reducing the numerical bit width of the model,which improves the computation speed. Because different layers have different redundancy and sensitivity to d... The quantization algorithm compresses the original network by reducing the numerical bit width of the model,which improves the computation speed. Because different layers have different redundancy and sensitivity to databit width. Reducing the data bit width will result in a loss of accuracy. Therefore, it is difficult to determinethe optimal bit width for different parts of the network with guaranteed accuracy. Mixed precision quantizationcan effectively reduce the amount of computation while keeping the model accuracy basically unchanged. In thispaper, a hardware-aware mixed precision quantization strategy optimal assignment algorithm adapted to low bitwidth is proposed, and reinforcement learning is used to automatically predict the mixed precision that meets theconstraints of hardware resources. In the state-space design, the standard deviation of weights is used to measurethe distribution difference of data, the execution speed feedback of simulated neural network accelerator inferenceis used as the environment to limit the action space of the agent, and the accuracy of the quantization model afterretraining is used as the reward function to guide the agent to carry out deep reinforcement learning training. Theexperimental results show that the proposed method obtains a suitable model layer-by-layer quantization strategyunder the condition that the computational resources are satisfied, and themodel accuracy is effectively improved.The proposed method has strong intelligence and certain universality and has strong application potential in thefield of mixed precision quantization and embedded neural network model deployment. 展开更多
关键词 Mixed precision quantization quantization strategy optimal assignment reinforcement learning neural network model deployment
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Image Steganography by Pixel-Value Differencing Using General Quantization Ranges
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作者 Da-Chun Wu Zong-Nan Shih 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期353-383,共31页
A new steganographic method by pixel-value differencing(PVD)using general quantization ranges of pixel pairs’difference values is proposed.The objective of this method is to provide a data embedding technique with a ... A new steganographic method by pixel-value differencing(PVD)using general quantization ranges of pixel pairs’difference values is proposed.The objective of this method is to provide a data embedding technique with a range table with range widths not limited to powers of 2,extending PVD-based methods to enhance their flexibility and data-embedding rates without changing their capabilities to resist security attacks.Specifically,the conventional PVD technique partitions a grayscale image into 1×2 non-overlapping blocks.The entire range[0,255]of all possible absolute values of the pixel pairs’grayscale differences in the blocks is divided into multiple quantization ranges.The width of each quantization range is a power of two to facilitate the direct embedding of the bit information with high embedding rates.Without using power-of-two range widths,the embedding rates can drop using conventional embedding techniques.In contrast,the proposed method uses general quantization range widths,and a multiple-based number conversion mechanism is employed skillfully to implement the use of nonpower-of-two range widths,with each pixel pair being employed to embed a digit in the multiple-based number.All the message bits are converted into a big multiple-based number whose digits can be embedded into the pixel pairs with a higher embedding rate.Good experimental results showed the feasibility of the proposed method and its resistance to security attacks.In addition,implementation examples are provided,where the proposed method adopts non-power-of-two range widths and employsmultiple-based number conversion to expand the data-hiding and steganalysis-resisting capabilities of other PVD methods. 展开更多
关键词 STEGANOGRAPHY pixel-value differencing multiple-based number conversion general quantization range
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A Novel Quantization and Model Compression Approach for Hardware Accelerators in Edge Computing
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作者 Fangzhou He Ke Ding +3 位作者 DingjiangYan Jie Li Jiajun Wang Mingzhe Chen 《Computers, Materials & Continua》 SCIE EI 2024年第8期3021-3045,共25页
Massive computational complexity and memory requirement of artificial intelligence models impede their deploy-ability on edge computing devices of the Internet of Things(IoT).While Power-of-Two(PoT)quantization is pro... Massive computational complexity and memory requirement of artificial intelligence models impede their deploy-ability on edge computing devices of the Internet of Things(IoT).While Power-of-Two(PoT)quantization is pro-posed to improve the efficiency for edge inference of Deep Neural Networks(DNNs),existing PoT schemes require a huge amount of bit-wise manipulation and have large memory overhead,and their efficiency is bounded by the bottleneck of computation latency and memory footprint.To tackle this challenge,we present an efficient inference approach on the basis of PoT quantization and model compression.An integer-only scalar PoT quantization(IOS-PoT)is designed jointly with a distribution loss regularizer,wherein the regularizer minimizes quantization errors and training disturbances.Additionally,two-stage model compression is developed to effectively reduce memory requirement,and alleviate bandwidth usage in communications of networked heterogenous learning systems.The product look-up table(P-LUT)inference scheme is leveraged to replace bit-shifting with only indexing and addition operations for achieving low-latency computation and implementing efficient edge accelerators.Finally,comprehensive experiments on Residual Networks(ResNets)and efficient architectures with Canadian Institute for Advanced Research(CIFAR),ImageNet,and Real-world Affective Faces Database(RAF-DB)datasets,indicate that our approach achieves 2×∼10×improvement in the reduction of both weight size and computation cost in comparison to state-of-the-art methods.A P-LUT accelerator prototype is implemented on the Xilinx KV260 Field Programmable Gate Array(FPGA)platform for accelerating convolution operations,with performance results showing that P-LUT reduces memory footprint by 1.45×,achieves more than 3×power efficiency and 2×resource efficiency,compared to the conventional bit-shifting scheme. 展开更多
关键词 Edge computing model compression hardware accelerator power-of-two quantization
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Hierarchical Controller Synthesis Under Linear Temporal Logic Specifications Using Dynamic Quantization
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作者 Wei Ren Zhuo-Rui Pan +1 位作者 Weiguo Xia Xi-Ming Sun 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第10期2082-2098,共17页
Linear temporal logic(LTL)is an intuitive and expressive language to specify complex control tasks,and how to design an efficient control strategy for LTL specification is still a challenge.In this paper,we implement ... Linear temporal logic(LTL)is an intuitive and expressive language to specify complex control tasks,and how to design an efficient control strategy for LTL specification is still a challenge.In this paper,we implement the dynamic quantization technique to propose a novel hierarchical control strategy for nonlinear control systems under LTL specifications.Based on the regions of interest involved in the LTL formula,an accepting path is derived first to provide a high-level solution for the controller synthesis problem.Second,we develop a dynamic quantization based approach to verify the realization of the accepting path.The realization verification results in the necessity of the controller design and a sequence of quantization regions for the controller design.Third,the techniques of dynamic quantization and abstraction-based control are combined together to establish the local-to-global control strategy.Both abstraction construction and controller design are local and dynamic,thereby resulting in the potential reduction of the computational complexity.Since each quantization region can be considered locally and individually,the proposed hierarchical mechanism is more efficient and can solve much larger problems than many existing methods.Finally,the proposed control strategy is illustrated via two examples from the path planning and tracking problems of mobile robots. 展开更多
关键词 Abstraction-based control design dynamic quantization formal methods linear temporal logic(LTL)
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Rate distortion optimization for adaptive gradient quantization in federated learning
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作者 Guojun Chen Kaixuan Xie +4 位作者 Wenqiang Luo Yinfei Xu Lun Xin Tiecheng Song Jing Hu 《Digital Communications and Networks》 CSCD 2024年第6期1813-1825,共13页
Federated Learning(FL)is an emerging machine learning framework designed to preserve privacy.However,the continuous updating of model parameters over uplink channels with limited throughput leads to a huge communicati... Federated Learning(FL)is an emerging machine learning framework designed to preserve privacy.However,the continuous updating of model parameters over uplink channels with limited throughput leads to a huge communication overload,which is a major challenge for FL.To address this issue,we propose an adaptive gradient quantization approach that enhances communication efficiency.Aiming to minimize the total communication costs,we consider both the correlation of gradients between local clients and the correlation of gradients between communication rounds,namely,in the time and space dimensions.The compression strategy is based on rate distortion theory,which allows us to find an optimal quantization strategy for the gradients.To further reduce the computational complexity,we introduce the Kalman filter into the proposed approach.Finally,numerical results demonstrate the effectiveness and robustness of the proposed rate-distortion optimization adaptive gradient quantization approach in significantly reducing the communication costs when compared to other quantization methods. 展开更多
关键词 Federated learning Communication efficiency Adaptive quantization Rate distortion
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Quantization of Action for Elementary Particles and the Principle of Least Action
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作者 Shuming Wen 《Journal of Modern Physics》 2024年第9期1430-1447,共18页
The uncertainty principle is a fundamental principle of quantum mechanics, but its exact mathematical expression cannot obtain correct results when used to solve theoretical problems such as the energy levels of hydro... The uncertainty principle is a fundamental principle of quantum mechanics, but its exact mathematical expression cannot obtain correct results when used to solve theoretical problems such as the energy levels of hydrogen atoms, one-dimensional deep potential wells, one-dimensional harmonic oscillators, and double-slit experiments. Even after approximate treatment, the results obtained are not completely consistent with those obtained by solving Schrödinger’s equation. This indicates that further research on the uncertainty principle is necessary. Therefore, using the de Broglie matter wave hypothesis, we quantize the action of an elementary particle in natural coordinates and obtain the quantization condition and a new deterministic relation. Using this quantization condition, we obtain the energy level formulas of an elementary particle in different conditions in a classical way that is completely consistent with the results obtained by solving Schrödinger’s equation. A new physical interpretation is given for the particle eigenfunction independence of probability for an elementary particle: an elementary particle is in a particle state at the space-time point where the action is quantized, and in a wave state in the rest of the space-time region. The space-time points of particle nature and the wave regions of particle motion constitute the continuous trajectory of particle motion. When an elementary particle is in a particle state, it is localized, whereas in the wave state region, it is nonlocalized. 展开更多
关键词 Elementary Particle quantization of Action Deterministic Relation Inherent State Nonprobabilistic Interpretation Localization Region Nonlocalization Region
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Does There Exist the Applicability Limit of PDE to Describe Physical Phenomena?—A Personal Survey of Quantization, QED, Turbulence
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作者 Atsushi Inoue 《World Journal of Mechanics》 2024年第6期97-142,共46页
What does it mean to study PDE (Partial Differential Equation)? How and what to do “to claim proudly that I’m studying a certain PDE”? Newton mechanic uses mainly ODE (Ordinary Differential Equation) and describes ... What does it mean to study PDE (Partial Differential Equation)? How and what to do “to claim proudly that I’m studying a certain PDE”? Newton mechanic uses mainly ODE (Ordinary Differential Equation) and describes nicely movements of Sun, Moon and Earth etc. Now, so-called quantum phenomenum is described by, say Schrödinger equation, PDE which explains both wave and particle characters after quantization of ODE. The coupled Maxwell-Dirac equation is also “quantized” and QED (Quantum Electro-Dynamics) theory is invented by physicists. Though it is said this QED gives very good coincidence between theoretical1 and experimental observed quantities, but what is the equation corresponding to QED? Or, is it possible to describe QED by “equation” in naive sense? 展开更多
关键词 SUPERSPACE Grassmann Variables Hamilton-Jacobi Equation quantization
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传感信号宽带噪声实时自适应抑制方法 被引量:1
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作者 文玉梅 朱宇 《电子与信息学报》 北大核心 2025年第8期2746-2756,共11页
自适应滤波是滤除传感输出中宽带噪声的常用方法。自适应过程跟随传感信号统计特征的变化进行调整,收敛时自适应滤波器输出为传感信号的最优估计,而收敛前的调整过程中输出并非最优,且会产生畸变引入额外噪声。该文根据噪声标准差σ对... 自适应滤波是滤除传感输出中宽带噪声的常用方法。自适应过程跟随传感信号统计特征的变化进行调整,收敛时自适应滤波器输出为传感信号的最优估计,而收敛前的调整过程中输出并非最优,且会产生畸变引入额外噪声。该文根据噪声标准差σ对传感输出进行实时量化变换,变换结果基本保持平稳,且保留传感信号和噪声信息。以变换结果为待滤波信号,自适应滤波器一旦收敛就始终处于收敛状态。对实际传感输出的处理表明,该方法适用于各类传感输出的宽带噪声实时抑制,输出不会产生畸变引入额外噪声。 展开更多
关键词 宽带噪声 噪声抑制 量化 实时滤波 自适应算法
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智能物联网中高效安全的自适应量化联邦学习 被引量:2
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作者 马海英 沈金宇 +2 位作者 杨天玲 仇健 王占君 《计算机应用研究》 北大核心 2025年第8期2503-2510,共8页
针对现有自适应量化联邦学习存在参与者本地模型参数隐私泄露的问题,提出一种适合智能物联网的高效安全的自适应量化联邦学习方案。该方案利用自适应量化技术减少参与者的通信开销,设置两个聚合服务器,将Diffie-Hellman密钥交换协议、... 针对现有自适应量化联邦学习存在参与者本地模型参数隐私泄露的问题,提出一种适合智能物联网的高效安全的自适应量化联邦学习方案。该方案利用自适应量化技术减少参与者的通信开销,设置两个聚合服务器,将Diffie-Hellman密钥交换协议、秘密共享方案和不经意传输协议相结合,构造一种保护本地模型参数隐私的安全聚合协议,并在合理假设下证明所提方案的安全性。实验结果表明该方案能够获得较高准确率的全局模型,极大减少了参与者的通信开销和隐私保护计算开销,非常适用于智能物联网中资源受限的轻量级物联网设备。 展开更多
关键词 联邦学习 隐私保护 自适应量化 秘密共享 不经意传输协议
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基于改进人工势场法的欠驱动无人船编队协同避碰避障 被引量:1
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作者 李伟 张永超 +3 位作者 宁君 马昊冉 刘陆 彭周华 《控制与决策》 北大核心 2025年第1期252-260,共9页
提出一种基于改进人工势场法且带有输入量化的欠驱动无人船编队协同避碰避障策略.借鉴导弹制导与控制机理,分层设计无人船运动学制导律与动力学控制律.首先,基于辅助变量法在无人船运动学子系统中设计分布式制导律,并引入改进人工势场... 提出一种基于改进人工势场法且带有输入量化的欠驱动无人船编队协同避碰避障策略.借鉴导弹制导与控制机理,分层设计无人船运动学制导律与动力学控制律.首先,基于辅助变量法在无人船运动学子系统中设计分布式制导律,并引入改进人工势场法的斥力函数.通过重构制导律实现运动学层面的协同避碰避障以及欠驱动无人船期望轨迹的跟踪;其次,通过使用径向基神经网络对无人船动力学子系统中的外界干扰和系统未建模动态进行逼近,采用均匀量化器对输入变量进行量化并对量化过程进行线性描述,使得底层量化控制器无需预测关于量化参数的具体信息;在稳定性分析中,利用李雅普诺夫稳定性理论证明所设计USV编队跟踪控制系统的稳定性;最后,采用Matlab对理论策略进行仿真实验,仿真结果验证了所提出策略的有效性. 展开更多
关键词 欠驱动无人船 人工势场法 分布式编队 输入量化 RBF神经网络 避障
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带有状态/输入量化的无人船有限时间航向跟踪控制
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作者 宁君 马一帆 +1 位作者 李志慧 李伟 《哈尔滨工程大学学报》 北大核心 2025年第9期1701-1708,共8页
针对在无人船航向跟踪控制过程中海上通信带宽受限的问题,本文依据Terminal滑模控制方法,利用扩张状态观测器估计量化状态系统未建模动态及外界干扰,基于估计信息设计系统控制律,提出一种考虑状态和输入量化的无人船有限时间航向跟踪控... 针对在无人船航向跟踪控制过程中海上通信带宽受限的问题,本文依据Terminal滑模控制方法,利用扩张状态观测器估计量化状态系统未建模动态及外界干扰,基于估计信息设计系统控制律,提出一种考虑状态和输入量化的无人船有限时间航向跟踪控制策略。仿真结果表明:在基于量化的控制环境下,所设计的航向跟踪控制方法能够保证无人船在快速跟踪理想航向的同时,跟踪误差收敛,且控制输入经过量化后执行器执行次数明显减少。因此,所设计的带有状态量化和输入量化的船舶航向跟踪控制策略是可行的,在实现有限时间内有效跟踪的同时,减轻了海上通信信号传输负担。 展开更多
关键词 无人船 航向跟踪控制 扩张状态观测器 状态量化 输入量化 量化误差 TERMINAL滑模控制 有限时间
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基于改进EFD-小波去噪算法的岩石压裂声发射信号分类 被引量:1
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作者 王婷婷 霍雨佳 +2 位作者 赵万春 史晓东 李方 《无损检测》 2025年第1期52-59,共8页
为准确识别岩石破裂过程中不同阶段产生的声发射信号,提出了一种改进经验傅里叶分解(Empirical Fourier decomposition,EFD)-小波去噪算法,对采集的声发射信号进行降噪处理后,将提取特征输入学习向量量化(Learning vector quantization,... 为准确识别岩石破裂过程中不同阶段产生的声发射信号,提出了一种改进经验傅里叶分解(Empirical Fourier decomposition,EFD)-小波去噪算法,对采集的声发射信号进行降噪处理后,将提取特征输入学习向量量化(Learning vector quantization,LVQ)算法中进行识别分类。首先,使用改进后的EFD算法将岩心破裂的声发射信号进行分解,设定方差贡献率为筛选条件,用小波阈值去噪法进一步滤除噪声后重构信号;然后,用高斯混合模型得到特征向量概率分布,对破裂过程的不同阶段进行分析;最后,提取声发射信号的参数构造特征向量,根据LVQ算法对岩心破裂声发射信号进行分类识别。试验结果表明,该方法可以依据声发射信号准确识别岩心破裂的不同阶段。 展开更多
关键词 岩石破裂声发射信号 傅里叶分解 谱峭度 高斯混合模型 学习向量量化
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无人机载单比特NanoSAR系统
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作者 王伟 龙天尧 黄磊 《雷达科学与技术》 北大核心 2025年第1期32-38,66,共8页
本研究旨在开发一种基于调频连续波的无人机载单比特微型合成孔径雷达(NanoSAR)系统。该系统具有微型化和低功耗等优势,能够在低空遥感作业中快速获取高分辨率图像。在保持成像质量的前提下,为了降低系统功耗,本文对单比特成像技术进行... 本研究旨在开发一种基于调频连续波的无人机载单比特微型合成孔径雷达(NanoSAR)系统。该系统具有微型化和低功耗等优势,能够在低空遥感作业中快速获取高分辨率图像。在保持成像质量的前提下,为了降低系统功耗,本文对单比特成像技术进行研究,通过一位量化减少数据量,并结合频谱偏移技术有效抑制高次谐波对成像质量的影响。我们将NanoSAR系统搭载于中小型无人机进行数据采集,采用基于距离徙动校准的距离多普勒算法对回波数据进行成像处理,并对单比特数据的SAR成像效果进行了验证。 展开更多
关键词 调频连续波 微型合成孔径雷达 单比特量化 雷达信号处理
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基于多尺度量化特征的视频异常行为检测算法
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作者 马建红 王亚辉 +1 位作者 靳岩 卫权岗 《郑州大学学报(理学版)》 北大核心 2025年第5期39-45,共7页
视频异常行为检测在监控安防领域具有很高的应用价值。针对生成视频帧的自编码器模型在编码器与解码器间进行跳跃连接时会导致异常信息泛化的问题,提出一种基于多尺度量化特征的视频异常行为检测算法。首先,编码器学习正常帧并分层进行... 视频异常行为检测在监控安防领域具有很高的应用价值。针对生成视频帧的自编码器模型在编码器与解码器间进行跳跃连接时会导致异常信息泛化的问题,提出一种基于多尺度量化特征的视频异常行为检测算法。首先,编码器学习正常帧并分层进行矢量量化,解码器根据量化后的特征进行视频帧生成,避免了编码器和解码器之间直接进行信息传递,显著降低了泛化影响,提高帧生成质量。其次,对生成的帧使用金字塔变形模块进行多样性测量,通过计算生成帧和原始帧的变形来测量异常的严重程度。最后,融合生成帧的重建误差计算得到异常评分。在公共数据集上测试了算法的异常检测性能,实验结果显示,所提算法的AUC值均高于同类算法。 展开更多
关键词 视频异常检测 多尺度 矢量量化 变分自编码器
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