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State-sensitive convolutional sparse coding for potential biomarker identification in brain signals

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Science China(Information Sciences) 2024年第5期67卷 270-286页

作者： Puli WANG Yu QI Gang pan College of Computer Science and Technology Zhejiang University State Key Laboratory of Brain-Machine Intelligence Zhejiang University MOE Frontier Science Center for Brain Science and Brain-machine Integration Zhejiang University Affiliated Mental Health Center & Hangzhou Seventh People's Hospital Zhejiang University School of Medicine

The identification of prototypical waveforms, such as sleep spindles and epileptic spikes, is crucial for the diagnosis of neurological disorders. These prototypical waveforms are usually recurrently presented in certain brain states, serving as potential biomarkers for clinical evaluations. Convolutional sparse coding(CSC) approaches have demonstrated strength in identifying recurrent patterns in time-series. However,existing CSC approaches do not explicitly explore state-specific patterns, making it difficult to identify state-related biomarkers. To address this problem, we propose state-sensitive CSC to learn state-specific prototypical waveforms. Specifically, we model signals of a certain state with specific waveforms that only appear frequently in this state and background waveforms that are independent of states. Based on this,state-sensitive CSC separates state-specific waveforms from background ones explicitly by incorporating incoherence constraints into optimizations. Experiments with epilepsy brain signals demonstrate that our approach can effectively identify prototypical waveforms in pre-ictal states, providing potential biomarkers for seizure prediction. Our approach provides a promising tool for automatic biomarker candidate identification.

关键词： convolutional sparse coding prototypical waveforms state-specific dictionary biomarker identification neural signal processing

A numerical simulation strategy for a compressor’s underlying axisymmetric characteristic and its application in body force model

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Chinese Journal of Aeronautics 2024年第8期37卷 79-90页

作者： Shijie LIU Tianyu pan Qiushi LI School of Energy and Power Engineering Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China Key Laboratory of Fluid and Power Machinery Ministry of EducationXihua UniversityChengdu 610039China

Accurate prediction of the aerodynamic response of a compressor under inlet distortion is crucial for next-generation civil aircraft,such as Boundary Layer Ingestion(BLI)silent ***,research on the Body Force(BF)model plays a significant role in achieving this ***,distorted inlet airflow can lead to varying operating conditions across different spatial locations of the compressor,which may cause some regions to operate outside the stability ***,the accuracy of BF model simulations might be *** address this issue,this paper proposes a numerical simulation strategy for acquiring the steady axisymmetric three-dimensional flow field of a compressor operating at low mass flow rates,which is known as the Underlying Axisymmetric Pressure Rise Characteristic(UAPRC).The proposed simulation accounts for two different rotor speeds of a transonic compressor and identifies initial positions in the flow field where deterioration occurs based on prior experimental ***,simulation results are incorporated into the BF model to replicate hub instability observed in *** results demonstrate that this strategy provides valid predictions of the UAPRC of the compressor,thereby addressing the limitations associated with the BF model.

关键词： Compressor partial instability Performance at low mass flow rates Underlying axisymmetric pressure rise characteristic Novel simulation strategy Body force model

2-local unstable homotopy groups of indecomposable A3～2-complexes

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Science China Mathematics 2024年第3期67卷 607-626页

作者： Zhongjian Zhu Jianzhong pan College of Mathematics and Physics Wenzhou University Hua Loo-Keng Key Laboratory of Mathematics Institute of MathematicsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper,we calculate the 2-local unstable homotopy groups of indecomposable A3～*** main technique used is analysing the homotopy property of J（A,X）,defined by Gray（1973） for a CW-pair（X,A）,which is homoto... 详细信息

关键词： homotopy groups A 2 n -complexes fibration sequence relative James construction 55P15

Determination method of mesh size for numerical simulation of blast load in near-ground detonation

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Defence Technology（防务技术） 2024年第8期38卷 111-125页

作者： Doudou Si Zuanfeng pan Haipeng Zhang College of Civil Engineering Tongji UniversityShanghai 200092China State Key Lab of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

In order to improve the overall resilience of the urban infrastructures, it is required to conduct blast resistant design for important building structures in the city. For complex terrain in the city, it is recommended to determine the blast load on the structures via numerical simulation. Since the mesh size of the numerical model highly depends on the explosion scenario, there is no generally applicable approach for the mesh size selection. An efficient method to determine the mesh size of the numerical model of near-ground detonation based on explosion scenarios is proposed in this study. The effect of mesh size on the propagation of blast wave under different explosive weights was studied, and the correlations between the mesh size effect and the charge weight or the scaled distance was described. Based on the principle of the finite element method and Hopkinson-Cranz scaling law, a mesh size measurement unit related to the explosive weight was proposed as the criterion for determining the mesh size in the numerical simulation. Finally, the applicability of the method proposed in this paper was verified by comparing the results from numerical simulation and the explosion tests and was verified in AUTODYN.

关键词： Blast load Mesh size effect Numerical simulation Scaled mesh size Verification

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Thermal-hydraulic performance analysis and multi-objective optimization of a microchannel with staggered semi-elliptical ribs

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Science China Technological Sciences 2024年第10期67卷 3152-3167页

作者： CUI pan LIU Wei LIU ZhiChun School of Energy and Power Engineering Huazhong University of Science and Technology

To enhance the cooling capacity of traditional microchannels for high heat flux electronic devices,a microchannel design with staggered semi-elliptical ribs is proposed in this *** numerical simulations,the flow characteristics of the designed microchannel are compared with those of a smooth one,and the effects of rib width（Wr）,rib height（Hr）,and rib length（Lr）,on the thermal-hydraulic performance are investigated under laminar flow *** results show that the periodically arranged ribs induce periodic vortices within the microchannel,effectively promoting fluid mixing and enhancing heat *** Hrhave similar effects on microchannel performance,with an increase in them leading to an enhanced thermal performance at the expense of deteriorated hydraulic ***,Lrhas a comparatively weaker influence,with both the heat transfer and flow resistance initially growing with increasing Lrand then *** strike a balance between the two performances,a multi-objective optimization on the three geometrical parameters is conducted at a Reynolds number（Re） *** with simulation data,artificial neural networks are trained as surrogate models,and a multi-objective genetic algorithm is employed to derive the Pareto *** the TOPSIS decision-making method,an optimal compromise solution is determined as Wr=0.2415 mm,Hr=0.0976 mm,and Lr=0.6486 *** testing on the optimized microchannel reveals that it exhibits high heat transfer,middle flow resistance,and excellent overall performance,with the performance evaluation criterion（PEC） falling between 1.572 and 1.723 within the Re range of 220–660.

关键词： heat transfer enhancement microchannel semi-elliptical rib numerical simulation multi-objective optimization

Multiscale method for identifying and marking the multiform fractures from visible-light rock-mass images

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Underground Space 2024年第3期16卷 279-300页

作者： Yongbo pan Junzhi Cui Zhenhao Xu School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China The State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China Geotechnical and Structural Engineering Research Center Shandong UniversityJinan 250100China

Multiform fractures have a direct impact on the mechanical performance of rock *** accurately identify multiform fractures,the distribution patterns of grayscale and the differential features of fractures in their neighborhoods are *** on this,a multiscale processing algorithm is *** multiscale process is as *** the neighborhood of pixels,a grayscale continuous function is constructed using bilinear interpolation,the smoothing of the grayscale function is realized by Gaussian local filtering,and the grayscale gradient and Hessian matrix are calculated with high *** small-scale blocks,the pixels are classified by adaptively setting the grayscale threshold to identify potential line segments and *** the global image,potential line segments and mini-fillings are spliced together by progressing the block frontier layer-by-layer to identify and mark multiform *** accuracy of identifying multiform fractures is improved by constructing a grayscale continuous function and adaptively setting the grayscale thresholds on small-scale *** the layer-by-layer splicing algorithm is performed only on the domain of the 2-layer small-scale blocks,reducing the *** using rock mass images with different fracture types as examples,the identification results show that the proposed algorithm can accurately identify the multiform fractures,which lays the foundation for calculating the mechanical parameters of rock masses.

关键词： Visible light rock-mass images Continuous grayscale function Small-scale blocks Multiform fractures

Event-triggered predefined-time control for full-state constrained nonlinear systems: A novel command filtering error compensation method

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Science China(Technological Sciences) 2024年第9期67卷 2867-2880页

作者： pan YingNan CHEN YiLin LIANG HongJing College of Control Science and Engineering Bohai UniversityJinzhou 121013China School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing 100089China

In this paper, a command filter-based adaptive fuzzy predefined-time event-triggered tracking control problem is investigated for uncertain nonlinear systems with time-varying full-state constraints. By designing a sliding mode differentiator, the inherent computational complexity problem within the predefined-time backstepping framework is solved. Different from the existing command filter-based finite-time and fixed-time control strategies that the convergence time of the filtering error is adjusted through the system initial value or numerous parameters, a novel command filtering error compensation method is presented,which tunes one control parameter to make the filtering error converge in the predefined time, thereby reducing the complexity of design and analysis of processing the filtering error. Then, an improved event-triggered mechanism(ETM) that builds upon the switching threshold strategy, in which an inverse cotangent function is designed to replace the residual term of the ETM,is proposed to gradually release the controller's dependence on the residual term with increasing time. Furthermore, a tan-type nonlinear mapping technique is applied to tackle the time-varying full-state constraints problem. By the predefined-time stability theory, all signals in the uncertain nonlinear systems exhibit predefined-time stability. Finally, the feasibility of the proposed algorithm is substantiated through two simulation results.

关键词： predefined-time control command filtering error compensation method event-triggered mechanism time-varying full-state constraints uncertain nonlinear systems

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基于电力大数据的企业复工电力指数研究与应用

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浙江电力 2021年第2期40卷 26-32页

作者：尹积军潘巍巍国网浙江省电力有限公司杭州310007

疫情期间,企业复工情况不仅关系到地方税收和就业,还能深刻反映地方的经济和社会运转状况。准确掌握地区企业复工情况,既可帮助地方政府有效推动复工复产,也可辅助政府制定针对性防疫措施。通过收集浙江省内企业近3年春节期间电量相关... 详细信息

疫情期间,企业复工情况不仅关系到地方税收和就业,还能深刻反映地方的经济和社会运转状况。准确掌握地区企业复工情况,既可帮助地方政府有效推动复工复产,也可辅助政府制定针对性防疫措施。通过收集浙江省内企业近3年春节期间电量相关基础数据,提出了一种基于GMM(高斯混合模型)和Knee Point算法的企业复工电力指数计算方法。首先,利用GMM对企业进行聚类分析,将其分为春节停工企业和春节不停工企业;其次,利用Knee Point算法分析企业的用电曲线,对春节停工企业是否复工进行判断;最后,基于研究得到的企业复工电力指数模型计算浙江省内各地区复工电力指数,并将计算结果用于辅助政府进行复工复产决策。

关键词：复工复产电力大数据企业复工电力指数

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A blockchain-based data auditing scheme with key-exposure resistance for IIoT

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Science China(Information Sciences) 2024年第2期67卷 327-328页

作者： pan YANG Jingli REN Henan Academy of Big Data Zhengzhou University

The Industrial Internet of Things(IIoT) enables enterprises to collect data from end devices and outsource the data to cloud servers for flexible data sharing. Public auditing plays an important role in ensuring the integrity of the *** are blockchain-based public auditing schemes that utilize smart contracts to achieve decentralized verification(such as [1]),

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