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Fractal autoencoder with redundancy regularization for unsupervised feature selection

Science China(Information Sciences) 2025年第2期68卷 89-102页

作者： Meiting SUN Fangyu LI Honggui HAN School of Information Science and Technology Beijing University of Technology Beijing Key Laboratory of Computational Intelligence and Intelligent System Engineering Research Center of Digital Community Ministry of Education Beijing Institute of Artificial Intelligence

Feature selection is a crucial step in data preprocessing because feature selection reduces the dimensionality of data by eliminating irrelevant and redundant features. Since manual labeling is expensive, unsupervised feature selection has received increasing attention in recent years. However, existing unsupervised feature selection methods tend to prioritize selecting highly correlated features over exploring feature diversity. Thus, a regularized fractal autoencoder(RFAE) method is proposed to select informative features in an unsupervised way. Specifically, the fractal autoencoder network extends autoencoders to construct a correspondence neural network and a selection neural network. The correspondence neural network exploits interfeature correlations and the selection neural network selects the informative features. A redundancy regularization strategy consists of a redundancy elimination regularization term based on the dependency between features and a sparse regularization term based on the group lasso. The redundancy regularization strategy eliminates feature subset redundancy and enhances network generalization ability. Extensive experimental results on six publicly available datasets show that the proposed RFAE outperforms the compared methods regarding clustering accuracy and classification accuracy. Moreover, the proposed RFAE achieves acceptable computation efficiency.

关键词： unsupervised feature selection fractal autoencoder correspondence neural network selection neural network redundancy regularization strategy

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Design of off-axis reflective holographic optical elements in a holographic near-eye display system

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Optics Letters 2025年第9期50卷 3022-3025页

作者： Zhang, Shijie Tian, Yifan Liu, Juan Beijing Engineering Research Center for Mixed Reality and Advanced Display MoE Key Lab of Photoelectronic Imaging Technology and System School of Optics and Photonics Beijing Institute of Technology Beijing100081 China

Holographic optical elements (HOEs) span a wide application, such as virtual reality and augmented reality displays. However, due to the complex aperiodic structures in lens-type HOEs, the phase design faces difficulties in aberration optimization. Here, we present a method for the design of the off-axis reflective lens-type HOE. Considering the varying degrees of aberrations introduced by the varying object distances across different regions of the object plane, a straightforward yet effective local aberration compensation method is carried out through superimposing different mutually perpendicular cylindrical lens phases at different positions of the HOE. The optimized phase distribution of the HOE can be directly obtained for fabrication like holographic printing. The numerical results show that the field curvature (FC) and the interval of the imaging distance between the meridional plane and the sagittal plane are significantly reduced to 1% of their initial values, and the astigmatism is alleviated. The optical experiments are conducted using two spatial light modulators (SLMs), and the experimental results are in good agreement with the optimized ones. It is expected that the proposed method could be further applied for the development of holographic near-eye display (NED) devices. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

关键词： Augmented reality

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Fuzzy Terminal Sliding-Mode Control With Adaptive Switching Gain

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IEEE Transactions on Fuzzy systems 2025年第5期33卷 1499-1509页

作者： Feng, Cheng-Cheng Sun, Hao-Yuan Han, Hong-Gui Du, Sheng-Li Beijing University of Technology School of Information Science and Technology Beijing Key Laboratory of Computational Intelligence and Intelligent System Beijing Laboratory for Smart Environmental Protection Engineering Research Center of Digital Community Ministry of Education Beijing Artificial Intelligence Institute Beijing100124 China

For complex dynamic systems, it is a great challenge to design an appropriate control strategy to achieve stable tracking control. To solve this problem, a fuzzy terminal sliding-mode control method with adaptive switching gain (FTSC-ASG) is designed to improve the control performance in this article. First, an adaptive interval type-2 fuzzy prediction model (AIT2-FPM) is designed to approximate the complex nonlinearity and parameter uncertainty. Specifically, the state prediction error evaluated by predictor is utilized to design the weight adaptive law to improve the accuracy of the AIT2-FPM. Second, a terminal sliding-mode controller is utilized to obtain control input of the system in a finite time. To suppress the chattering phenomenon, the switching gain is designed based on the output of AIT2-FPM and the changes of control input information can be utilized to evaluate the degree of chattering. Furthermore, a parameter adaptive strategy is designed to adjust the parameter of equivalent control law. Third, FTSC-ASG can achieve fast convergence of tracking error, and the finite time stability of FTSC-ASG is proven in detail. Finally, the simulation studies in the third-order nonlinear system and the inverted pendulum systems are given to evaluate the effectiveness of FTSC-ASG. © 1993-2012 IEEE.

关键词： Sliding mode control

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Attribute-Based Access Control Encryption

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IEEE Transactions on Dependable and Secure Computing 2025年第3期22卷 2227-2242页

作者： Wang, Xiuhua Yu, Mengyang Wang, Yaohui Pi, Yinjia Xu, Peng Wang, Shuai Jin, Hai Han, Min Huazhong University of Science and Technology Hubei Key Laboratory of Distributed System Security School of Cyber Science and Engineering Wuhan430074 China State Key Laboratory of Cryptology Beijing100878 China Huazhong University of Science and Technology National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Hubei Key Laboratory of Distributed System Security Hubei Engineering Research Center on Big Data Security School of Cyber Science and Engineering Wuhan430074 China University of Electronic Science and Technology of China National Key Laboratory of Wireless Communications Chengdu611731 China Huazhong University of Science and Technology National Engineering Research Center for Big Data Technology and System Services Computing Technology and System Lab Cluster and Grid Computing Lab School of Computer Science and Technology Wuhan430074 China

The burgeoning complexity of communication necessitates a high demand for security. Access control encryption is a promising primitive to meet the security demand but the bulk of its constructions rely on formulating the access control policy with identities. Attribute-based access control policy in attribute-based encryption (ABE) is known to be more expressive without relying on enumerating identities. We propose a generic framework to build attribute-based access control encryption from ciphertext-policy ABE. Our instantiations prioritize different emphases on expressiveness and efficiency. The first instantiation supports multi-valued AND-gate access control structures, while the second supports the linear-secret-sharing access structure. Both are prototyped with efficiency validated empirically. © 2024 IEEE.

关键词： Ciphertext

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Using an optical fiber passive depolarizer to suppress the polarization dependence of stimulated Raman scattering gain in hydrogen sensor system 4

Using an optical fiber passive depolarizer to suppress the p...

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4th International Computational Imaging Conference, CITA 2024

作者： Shuzhi, Yao Xuan, Zheng Yong, Yang Meng, Jiang Hui, Gao Meng, Zhang Xuefeng, Wang Beijing Institute of Aerospace Control Device Beijing100094 China Beijing Optical Fiber Sensing System Engineering Technology Research Center Beijing100094 China

ISBN: (纸本)9781510688834

Optical fiber hydrogen sensors have recently received great attention because of the advantages of essential safety, anti-electromagnetic interference, corrosion resistance, suitable for long distance detection and so on. A new type of optical fiber hydrogen sensors based on stimulated Raman scattering spectroscopy and nanofiber was proposed several yeas ago which can realize ultra-fast, ultra-sensitive hydrogen detection with ultra-wide dynamic range. However, the Raman gain depends on the polarization states of the pump and Stokes beams and the Raman signal will drift when the fiber status or the environment temperature are changed. In this paper, we propose and demonstrate an optical fiber passive depolarizer to suppress the polarization dependence of stimulated Raman scattering gain in the aforementioned hydrogen sensor system. The depolarizer mainly consists of two fiber polarization beam splitters(PBSs) and a piece of delay fiber. The angle of incidence for any PBS is 45° and the delay fiber length is much longer than the coherent length of the input beam. The input beam is split into two beams by PBS1 one of which transfers through the delay fiber. Then these two beams are combined by PBS2 to obtain the output beam composed of two orthogonal beams with equal power, and their phase relationship changes randomly. By inserting the depolarizer into the pump beam path, the Raman signal will not be influenced by the changes of the fiber status or the environment temperature. This achievement would be very useful for real application of the hydrogen sensor in long distance detection and multi-channel sensing system. © 2025 SPIE.

关键词： Stimulated Raman scattering

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Development of a high-resolution near-surface meteorological forcing dataset for the Third Pole region

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Science China Earth Sciences 2025年第4期68卷 1274-1290页

作者： Yaozhi JIANG Wenjun TANG Kun YANG Jie HE Changkun SHAO Xu ZHOU Hui LU Yingying CHEN Xin LI Jiancheng SHI School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu611731China Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing100084China National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth SystemEnvironment and ResourcesInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Tsinghua University(Department of Earth System Science)-Xi’an Institute of Surveying and Mapping Joint Research Center for Next-Generation Smart Mapping Beijing100084China National Space Science Center Chinese Academy of SciencesBeijing100190China

Recently,the Third Pole(TP)region has experienced rapid environmental *** data are essential for hydrometeorological and ecological applications but still have large uncertainties on the TP owing to the heterogeneous land surface,complex terrain,and sparse weather *** this study,a long-term(1979–2020)high-resolution(1/30°)meteorological forcing dataset for the TP(TPMFD)was developed,as a sister to the widely used China Meteorological Forcing Dataset(CMFD).The TPMFD comprises seven components necessary for driving land surface *** have previously contributed precipitation and downward shortwave radiation data for the TPMFD,and this study presents the development of five other components and focuses on validations for all ***,2-meter air temperature,2-meter specific humidity,10-meter wind speed,and surface air pressure were generated by combining the fifth-generation atmospheric reanalysis for European center for Medium-Range Weather Forecasts(ERA5),a short-term high-resolution atmospheric simulation,and in situ observations,and the downward longwave radiation was calculated using semi-physical *** cross-validation and independent-validation demonstrated that most variables in the developed dataset outperformed those in widely used reanalysis datasets,including ERA5,ERA5-Land,and the Global Land Data Assimilation system(GLDAS).This dataset is expected to be beneficial for climate analyses and modeling applications of land-surface processes on the TP.

关键词： Meteorological data Third Pole High-resolution Data downscaling and merging

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AdaptHM: A Fully Adaptive Data Migration Strategy for Hybrid Memory systems

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IEEE Transactions on Computer-Aided Design of Integrated Circuits and systems 2025年第3期44卷 923-936页

作者： Peng, Zhouxuan Feng, Dan Chen, Jianxi Hu, Jing Liu, Yachun Hu, Jinlei Zhang, Jintong Wan, Tianyu Chen, Zuoning Huazhong University of Science and Technology Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System Engineering Research Center of Data Storage Systems and Technology MoE of China Wuhan430074 China Chinese Academy of Engineering Beijing100088 China

Data migration strategies (DMSs) improve the overall performance of hybrid memory systems by migrating frequently accessed (hot) data to faster memory. However, designing an efficient DMS is challenging since the key metrics of DMS - hot data selection, migration granularity, and migration frequency - are sensitive to access patterns of workloads. Most existing strategies focus on only one of these metrics and often overlook the crucial impact of access patterns, resulting in suboptimal performance and unnecessary migration traffic. In this article, we propose AdaptHM, a fully access-pattern-aware Adaptive DMS for Hybrid Memory systems. AdaptHM achieves adaptability on all three metrics through its unique multilevel data framework. First, AdaptHM adopts a group-level competition policy to select hot blocks, which responds faster to access patterns than threshold-based policies. Second, AdaptHM enables segment-level dynamic migration granularity by decoupling migration from remapping, which shows better-access pattern resilience than existing schemes with fixed-size global migration granularity. Third, AdaptHM adjusts the migration frequency at set-level by periodically assessing the migration benefit, avoiding unnecessary migrations. Experimental results demonstrate that AdaptHM improves the performance by an average of 12.78% and reduces energy consumption by up to 37.24% compared to the state-of-the-art scheme. © 1982-2012 IEEE.

关键词： Frequency modulation

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Reinforced Prescribed Performance Control for Virtually-coupled Trains with Saltatory Targets and Switching Constraints

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IEEE Transactions on Automation Science and engineering 2025年 22卷 15251-15263页

作者： Si, Wenxiao Gao, Shigen Zhang, Miao Zhang, Hang Wang, Hongwei Beijing Jiaotong University School of Automation and Intelligence Beijing100044 China China Academy of Railway Science Center of National Railway Intelligent Transportation System Engineering and Technology Beijing100081 China National Railway Administration of the People’s Republic of China Planning and Standard Research Institute Beijing100055 China

Virtual Coupling (VC) has emerged as a promising strategy for railway system control, offering significant enhancements to rail-line capacity and addressing uneven transport demand by dynamically minimizing the headway distance between trains when necessary. Consequently, the operating targets of VC rear trains, which can be influenced by operational environments and railway line conditions, must be promptly adjusted based on the spacing from the adjacent leading train. This adjustment ensures operational safety within the train movement authority. Different from traditional continuous prescribed performance control (PPC), this paper proposes a discontinuous reinforced prescribed performance control (RPPC) strategy, which takes into account both actual and converted errors and introduces innovative segmented dynamic control strategies designed for continuous operation time periods and discontinuous impulse points. To prevent unnecessary disruptive switching during transient moments, switching constraints (SCs), based on the speed and position of the rear train, are established. Additionally, leveraging Lyapunov theory, the stability of the closed-loop system for train operation is rigorously proven. Finally, a simulation scenario for a 3-train formation, along with a further data-based semi-physical simulation of a 2-train system, are presented for demonstrating the feasibility of the main results. © 2004-2012 IEEE.

关键词： Railroad transportation

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Resource Allocation for Fairness Enhancement in Multi-Cell Vehicular VLC system With Optical IRS: A Cooperative Transmission Approach

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IEEE Internet of Things Journal 2025年第11期12卷 16931-16946页

作者： An, Nan Yang, Fang Liu, Chang Cheng, Ling Song, Jian Han, Zhu Tsinghua University Beijing National Research Center for Information Science and Technology Department of Electronic Engineering Beijing100084 China Center of National Railway Intelligent Transportation System Engineering and Technology Beijing100081 China China Academy of Railway Sciences Corporation Limited Signal and Communication Research Institute Beijing100081 China University of the Witwatersrand School of Electrical and Information Engineering Johannesburg2050 South Africa Tsinghua University Department of Electronic Engineering Beijing National Research Center for Information Science and Technology Beijing100084 China Tsinghua University Shenzhen International Graduate School Shenzhen518055 China University of Houston Department of Electrical and Computer Engineering HoustonTX77004 United States Kyung Hee University Department of Computer Science and Engineering Seoul446-701 Korea Republic of

In multi-cell downlink vehicular visible light communication (VLC) systems, vehicles at a cell edge experience lower achievable data rates compared with those at a cell center, primarily due to the weaker channel gain and inter-cell interference, leading to unfairness among vehicles. In this paper, a cooperative transmission approach is proposed for a vehicular VLC system with optical intelligent reflecting surface (OIRS) to enhance the max-min fairness of the system by leveraging the additional OIRS-reflected channels and the interference-mitigating capabilities of cooperative transmission. To this end, the system model is established, followed by the formulation of a resource allocation problem aiming at enhancing max-min fairness, in which the minimum achievable data rate among vehicles is optimized. Then, an effective resource algorithm is proposed, transforming the original problem into an equivalent form and subsequently decomposing it into three subproblems, focusing on OIRS assignment, subchannel allocation, and power adjustment, respectively. By employing a block coordinate descent algorithm, the three subproblems are solved iteratively until convergence. In addition, simulation results confirm the improvement in max-min fairness brought by OIRS and the proposed cooperative transmission approach. Moreover, compared with various baselines, the proposed resource allocation algorithm significantly enhances in the max-min fairness for the vehicular VLC system, crucial for this application. © 2014 IEEE.

关键词： Resource allocation

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Temperature Behaviors of Receptor of Urban Rail Vehicle in Electrical Contact with Contact Rail

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IEEE Access 2025年 13卷 82291-82301页

作者： Xing, Tong Chen, Jianhua Yu, Zhiqiang Pan, Like Sun, Jianxiang Jin, An Cui, Yuehua Feng, Tao Yan, Wenxia Yi, Xudong Zhao, Zimeng China Academy of Railway Sciences Corporation Limited National Engineering Research Center of System Technology for High-Speed Railway and Urban Rail Transit Beijing100081 China China Academy of Railway Sciences Corporation Limited Standards & Metrology Research Institute Beijing100081 China Shijiazhuang Tiedao University School of Electrical and Electronic Engineering Shijiazhuang050043 China Railway Science & Technology Research & Development Center China Academy of Railway Sciences Corporation limited Beijing10081 China

Currently, many urban rail or subway vehicles obtain electrical energy through their receptors in contact with the contact rail linked to the traction network. As urban rail vehicles arrive at the station frequently or stop temporarily on the rail line, the contact rail still needs to provide the electric power for the on-board equipments. At this point, the receptor is in a static state, where the local overheating happens. This could lead to the damage of the receptor, even causing the vehicle to stop running. Based on the electrical contact theory and Fourier's law, this paper establishes a three-dimensional thermal field finite element model for the receptor and contact rail (referred to as the boot and rail, BAR). Using the model, the change of the contact resistance under the working conditions is investigated. And the effects of the contact force, transmitted (or power supply) current and receptor wear on the temperature behaviors of the receptor are discussed. The results show that the temperature is negatively related to the contact force but closely related to the contact resistance. When the contact force is less than 100 N, the contact resistance is larger and the temperature is obviously enhanced, with the rise rate of 0.05 ℃/s. The temperature of the receptor is positively related to the transmitted current. The larger the current, the higher the temperature, more intense the temperature rise;the smaller the current, the more obvious the saturation phenomenon of the temperature, i.e. the rapid attainment of the thermal equilibrium. The larger the wear area of the BAR, the larger the convective heat flux of the receptor, leading to a lower temperature in its steady state. The innovation of this paper is to establish a three-dimensional thermal field model that can more accurately characterize the BAR system under the static electrical contact, by applying the electrical contact theory to the finite element method. Its contribution is to provide a method

关键词： Urban transportation

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