期刊文献+
共找到245,374篇文章
< 1 2 250 >
每页显示 20 50 100
Pharmacological Investigation on the Qi-Invigorating Action of Schisandrin B: Effects on Mitochondrial ATP Generation in Multiple Tissues and Innate/Adaptive Immunity in Mice
1
作者 Hoi Yan Leung Suen Chit Sze Kam Ming Ko 《Chinese Medicine》 CAS 2024年第2期15-26,共12页
Schisandrae Fructus, containing schisandrin B (Sch B) as its main active component, is recognized in traditional Chinese medicine (TCM) for its Qi-invigorating properties in the five visceral organs. Our laboratory ha... Schisandrae Fructus, containing schisandrin B (Sch B) as its main active component, is recognized in traditional Chinese medicine (TCM) for its Qi-invigorating properties in the five visceral organs. Our laboratory has shown that the Qi-invigorating action of Chinese tonifying herbs is linked to increased mitochondrial ATP generation and an enhancement in mitochondrial glutathione redox status. To explore whether Sch B can exert Qi-invigorating actions across various tissues, we investigated the effects of Sch B treatment on mitochondrial ATP generation and glutathione redox status in multiple mouse tissues ex vivo. In line with TCM theory, which posits that Zheng Qi generation relies on the Qi function of the visceral organs, we also examined Sch B’s impact on natural killer cell activity and antigen-induced splenocyte proliferation, both serving as indirect measures of Zheng Qi. Our findings revealed that Sch B treatment consistently enhanced mitochondrial ATP generation and improved mitochondrial glutathione redox status in mouse tissues. This boost in mitochondrial function was associated with stimulated innate and adaptive immune responses, marked by increased natural killer cell activity and antigen-induced T/B cell proliferation, potentially through the increased generation of Zheng Qi. 展开更多
关键词 Zheng qi Schisandrin B MITOCHONDRIA ATP generation Glutathione Redox Innate Immunity Adaptive Immunity Natural Killer Cell Activity Splenocyte Proliferation
下载PDF
基于System Generator的卷积加速结构设计与实现
2
作者 成鸿群 刘宜成 +2 位作者 涂海燕 徐金鹏 王广泰 《计算机应用与软件》 北大核心 2024年第4期224-227,274,共5页
为解决卷积神经网络中卷积运算耗时长、运算复杂的问题,针对卷积运算的并行性特征,提出一种基于分块的流水线加速方法,并基于该方法在System Generator上进行了电路设计。通过在FPGA(Field-programmable Gate Array)上进行实验验证,该... 为解决卷积神经网络中卷积运算耗时长、运算复杂的问题,针对卷积运算的并行性特征,提出一种基于分块的流水线加速方法,并基于该方法在System Generator上进行了电路设计。通过在FPGA(Field-programmable Gate Array)上进行实验验证,该设计模型能正确输出卷积运算结果;在结构和输入数据相同的情况下,该设计模型在计算速度上相比于普通CPU最高可加速258倍,相比于服务器级CPU提高了近40倍,具有良好的加速效果。 展开更多
关键词 卷积神经网络 卷积运算 SYSTEM generATOR 现场可编程门阵列
下载PDF
类Chen-Qi混沌系统的固定时间自适应同步控制
3
作者 王院生 《动力学与控制学报》 2024年第7期80-86,共7页
类Chen-Qi四维混沌系统的渐近稳定控制的同步误差不能在有限时间内收敛到零,有限时间控制的同步误差收敛到零的状况与初值有关.因此,本文应用固定时间控制技术,设计了自适应控制器和参数估计律,试图使得驱动系统与同类型的参数未知的响... 类Chen-Qi四维混沌系统的渐近稳定控制的同步误差不能在有限时间内收敛到零,有限时间控制的同步误差收敛到零的状况与初值有关.因此,本文应用固定时间控制技术,设计了自适应控制器和参数估计律,试图使得驱动系统与同类型的参数未知的响应系统在固定时间内达到同步,完成了理论证明.应用数值仿真考察同步误差收敛到零的状况.选取不同参数值,不同状态初值,考察状态时程图、同步误差曲线等.结果表明:混沌运动时,固定时间内同步误差收敛到零的效果较好,与状态初值无关,收敛时间符合理论计算值;周期运动时,固定时间内前三个状态的同步误差收敛到零的效果较好,收敛时间符合理论计算值,但第四个状态的同步误差的收敛时间不符合理论计算值,其原因是系统存在的三次非线性项的不平衡、不匹配. 展开更多
关键词 类Chen-qi超混沌系统 固定时间同步 自适应控制器 同步误差 数值仿真
下载PDF
Computational Experiments for Complex Social Systems:Experiment Design and Generative Explanation 被引量:2
4
作者 Xiao Xue Deyu Zhou +5 位作者 Xiangning Yu Gang Wang Juanjuan Li Xia Xie Lizhen Cui Fei-Yue Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期1022-1038,共17页
Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a nove... Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a novel approach for the design,analysis,management,control,and integration of CPSS,which can realize the causal analysis of complex systems by means of“algorithmization”of“counterfactuals”.However,because CPSS involve human and social factors(e.g.,autonomy,initiative,and sociality),it is difficult for traditional design of experiment(DOE)methods to achieve the generative explanation of system emergence.To address this challenge,this paper proposes an integrated approach to the design of computational experiments,incorporating three key modules:1)Descriptive module:Determining the influencing factors and response variables of the system by means of the modeling of an artificial society;2)Interpretative module:Selecting factorial experimental design solution to identify the relationship between influencing factors and macro phenomena;3)Predictive module:Building a meta-model that is equivalent to artificial society to explore its operating laws.Finally,a case study of crowd-sourcing platforms is presented to illustrate the application process and effectiveness of the proposed approach,which can reveal the social impact of algorithmic behavior on“rider race”. 展开更多
关键词 Agent-based modeling computational experiments cyber-physical-social systems(CPSS) generative deduction generative experiments meta model
下载PDF
Correcting Climate Model Sea Surface Temperature Simulations with Generative Adversarial Networks:Climatology,Interannual Variability,and Extremes 被引量:2
5
作者 Ya WANG Gang HUANG +6 位作者 Baoxiang PAN Pengfei LIN Niklas BOERS Weichen TAO Yutong CHEN BO LIU Haijie LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第7期1299-1312,共14页
Climate models are vital for understanding and projecting global climate change and its associated impacts.However,these models suffer from biases that limit their accuracy in historical simulations and the trustworth... Climate models are vital for understanding and projecting global climate change and its associated impacts.However,these models suffer from biases that limit their accuracy in historical simulations and the trustworthiness of future projections.Addressing these challenges requires addressing internal variability,hindering the direct alignment between model simulations and observations,and thwarting conventional supervised learning methods.Here,we employ an unsupervised Cycle-consistent Generative Adversarial Network(CycleGAN),to correct daily Sea Surface Temperature(SST)simulations from the Community Earth System Model 2(CESM2).Our results reveal that the CycleGAN not only corrects climatological biases but also improves the simulation of major dynamic modes including the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole mode,as well as SST extremes.Notably,it substantially corrects climatological SST biases,decreasing the globally averaged Root-Mean-Square Error(RMSE)by 58%.Intriguingly,the CycleGAN effectively addresses the well-known excessive westward bias in ENSO SST anomalies,a common issue in climate models that traditional methods,like quantile mapping,struggle to rectify.Additionally,it substantially improves the simulation of SST extremes,raising the pattern correlation coefficient(PCC)from 0.56 to 0.88 and lowering the RMSE from 0.5 to 0.32.This enhancement is attributed to better representations of interannual,intraseasonal,and synoptic scales variabilities.Our study offers a novel approach to correct global SST simulations and underscores its effectiveness across different time scales and primary dynamical modes. 展开更多
关键词 generative adversarial networks model bias deep learning El Niño-Southern Oscillation marine heatwaves
下载PDF
Demonstration of a small‐scale power generator using supercritical CO_(2) 被引量:1
6
作者 Ligeng Li Hua Tian +7 位作者 Xin Lin Xianyu Zeng Yurong Wang Weilin Zhuge Lingfeng Shi Xuan Wang Xingyu Liang Gequn Shu 《Carbon Energy》 SCIE EI CAS CSCD 2024年第4期269-290,共22页
The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting th... The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting thermal energy into mechanical work and electric power.The operation of the generator encounters challenges,including high temperature,high pressure,high rotational speed,and other engineering problems,such as leakage.Experimental studies of sCO_(2)turbines are insufficient because of the significant difficulties in turbine manufacturing and system construction.Unlike most experimental investigations that primarily focus on 100 kW‐or MW‐scale power generation systems,we consider,for the first time,a small‐scale power generator using sCO_(2).A partial admission axial turbine was designed and manufactured with a rated rotational speed of 40,000 rpm,and a CO_(2)transcritical power cycle test loop was constructed to validate the performance of our manufactured generator.A resistant gas was proposed in the constructed turbine expander to solve the leakage issue.Both dynamic and steady performances were investigated.The results indicated that a peak electric power of 11.55 kW was achieved at 29,369 rpm.The maximum total efficiency of the turbo‐generator was 58.98%,which was affected by both the turbine rotational speed and pressure ratio,according to the proposed performance map. 展开更多
关键词 generATOR performance map power generation supercritical CO_(2) TURBINE
下载PDF
Design of Protograph LDPC-Coded MIMO-VLC Systems with Generalized Spatial Modulation 被引量:1
7
作者 Dai Lin Fang Yi +1 位作者 Guan Yongliang Mohsen Guizani 《China Communications》 SCIE CSCD 2024年第3期118-136,共19页
This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID ... This paper investigates the bit-interleaved coded generalized spatial modulation(BICGSM) with iterative decoding(BICGSM-ID) for multiple-input multiple-output(MIMO) visible light communications(VLC). In the BICGSM-ID scheme, the information bits conveyed by the signal-domain(SiD) symbols and the spatial-domain(SpD) light emitting diode(LED)-index patterns are coded by a protograph low-density parity-check(P-LDPC) code. Specifically, we propose a signal-domain symbol expanding and re-allocating(SSER) method for constructing a type of novel generalized spatial modulation(GSM) constellations, referred to as SSERGSM constellations, so as to boost the performance of the BICGSM-ID MIMO-VLC systems.Moreover, by applying a modified PEXIT(MPEXIT) algorithm, we further design a family of rate-compatible P-LDPC codes, referred to as enhanced accumulate-repeat-accumulate(EARA) codes,which possess both excellent decoding thresholds and linear-minimum-distance-growth property. Both analysis and simulation results illustrate that the proposed SSERGSM constellations and P-LDPC codes can remarkably improve the convergence and decoding performance of MIMO-VLC systems. Therefore, the proposed P-LDPC-coded SSERGSM-mapped BICGSMID configuration is envisioned as a promising transmission solution to satisfy the high-throughput requirement of MIMO-VLC applications. 展开更多
关键词 bit-interleaved coded modulation generalized spatial modulation multiple-input multipleoutput protograph LDPC codes visible light communication
下载PDF
Generating Time-Series Data Using Generative Adversarial Networks for Mobility Demand Prediction
8
作者 Subhajit Chatterjee Yung-Cheol Byun 《Computers, Materials & Continua》 SCIE EI 2023年第3期5507-5525,共19页
The increasing penetration rate of electric kickboard vehicles has been popularized and promoted primarily because of its clean and efficient features.Electric kickboards are gradually growing in popularity in tourist... The increasing penetration rate of electric kickboard vehicles has been popularized and promoted primarily because of its clean and efficient features.Electric kickboards are gradually growing in popularity in tourist and education-centric localities.In the upcoming arrival of electric kickboard vehicles,deploying a customer rental service is essential.Due to its freefloating nature,the shared electric kickboard is a common and practical means of transportation.Relocation plans for shared electric kickboards are required to increase the quality of service,and forecasting demand for their use in a specific region is crucial.Predicting demand accurately with small data is troublesome.Extensive data is necessary for training machine learning algorithms for effective prediction.Data generation is a method for expanding the amount of data that will be further accessible for training.In this work,we proposed a model that takes time-series customers’electric kickboard demand data as input,pre-processes it,and generates synthetic data according to the original data distribution using generative adversarial networks(GAN).The electric kickboard mobility demand prediction error was reduced when we combined synthetic data with the original data.We proposed Tabular-GAN-Modified-WGAN-GP for generating synthetic data for better prediction results.We modified The Wasserstein GAN-gradient penalty(GP)with the RMSprop optimizer and then employed Spectral Normalization(SN)to improve training stability and faster convergence.Finally,we applied a regression-based blending ensemble technique that can help us to improve performance of demand prediction.We used various evaluation criteria and visual representations to compare our proposed model’s performance.Synthetic data generated by our suggested GAN model is also evaluated.The TGAN-Modified-WGAN-GP model mitigates the overfitting and mode collapse problem,and it also converges faster than previous GAN models for synthetic data creation.The presented model’s performance is compared to existing ensemble and baseline models.The experimental findings imply that combining synthetic and actual data can significantly reduce prediction error rates in the mean absolute percentage error(MAPE)of 4.476 and increase prediction accuracy. 展开更多
关键词 Machine learning generative adversarial networks electric vehicle time-series TGAN WGAN-GP blend model demand prediction regression
下载PDF
The Essential Role of Zheng Qi in Promoting Health: From the Perspective of Chinese Medicine and Modern Medicine
9
作者 Kam Ming Ko Hoi Yan Leung 《Chinese Medicine》 CAS 2024年第2期27-33,共7页
The concept of Zheng Qi in traditional Chinese medicine (TCM) refers to the vital energy produced by the interaction of Yin and Yang forces in the body. Zheng Qi performs two main functions: Wei Qi (defensive Qi), whi... The concept of Zheng Qi in traditional Chinese medicine (TCM) refers to the vital energy produced by the interaction of Yin and Yang forces in the body. Zheng Qi performs two main functions: Wei Qi (defensive Qi), which shields the body from external pathogens, and Ying Qi (nutritive Qi), which sustains the internal organs and enhances their functionality. In TCM, Chinese tonifying herbs can help restore the balance of Yin/Yang and Qi/Blood function in visceral organs (i.e., optimal physiological functions), thereby fostering the efficient production of Zheng Qi and enhancing health. To ensure the quality of Chinese herbal products, functional assays to measure Yin/Yang, Qi/Blood functions, and Zheng Qi production should be implemented. The efficacy of Yang and Qi herbs can be evaluated by their ability to increase mitochondrial ATP in cultured mouse cardiomyocytes, while Yin and Blood herbs are tested through their immunostimulatory effects on antigen-induced T/B cell proliferation in mouse splenocytes and the production of erythropoietin/nitric oxide in hepatocytes/vascular endothelial cells, respectively. Additionally, Zheng Qi’s effect can be gauged by examining natural killer cell activity and antigen-induced T/B cell proliferation in mice ex vivo. These assays act as biomarkers for assessing the quality and effectiveness of herbal health products within TCM theory. 展开更多
关键词 Traditional Chinese Medicine Zheng qi IMMUNITY Biomarkers Functional Assays
下载PDF
TCM-HIN2Vec:A strategy for uncovering biological basis of heart qi deficiency pattern based on network embedding and transcriptomic experiment
10
作者 Lihong Diao Xinyi Fan +5 位作者 Jiang Yu Kai Huang Edouard C.Nice Chao Liu Dong Li Shuzhen Guo 《Journal of Traditional Chinese Medical Sciences》 CAS 2024年第3期264-274,共11页
Objective To elucidate the biological basis of the heart qi deficiency(HQD)pattern,an in-depth understanding of which is essential for improving clinical herbal therapy.Methods We predicted and characterized HQD patte... Objective To elucidate the biological basis of the heart qi deficiency(HQD)pattern,an in-depth understanding of which is essential for improving clinical herbal therapy.Methods We predicted and characterized HQD pattern genes using the new strategy,TCM-HIN2Vec,which involves heterogeneous network embedding and transcriptomic experiments.First,a heterogeneous network of traditional Chinese medicine(TCM)patterns was constructed using public databases.Next,we predicted HQD pattern genes using a heterogeneous network-embedding algorithm.We then analyzed the functional characteristics of HQD pattern genes using gene enrichment analysis and examined gene expression levels using RNA-seq.Finally,we identified TCM herbs that demonstrated enriched interactions with HQD pattern genes via herbal enrichment analysis.Results Our TCM-HIN2Vec strategy revealed that candidate genes associated with HQD pattern were significantly enriched in energy metabolism,signal transduction pathways,and immune processes.Moreover,we found that these candidate genes were significantly differentially expressed in the transcriptional profile of mice model with heart failure with a qi deficiency pattern.Furthermore,herbal enrichment analysis identified TCM herbs that demonstrated enriched interactions with the top 10 candidate genes and could potentially serve as drug candidates for treating HQD.Conclusion Our results suggested that TCM-HIN2Vec is capable of not only accurately identifying HQD pattern genes,but also deciphering the basis of HQD pattern.Furthermore our finding indicated that TCM-HIN2Vec may be further expanded to develop other patterns,leading to a new approach aimed at elucidating general TCM patterns and developing precision medicine. 展开更多
关键词 qi deficiency pattern Heart failure Biological basis Network embedding Transcriptome
下载PDF
IGED:Towards Intelligent DDoS Detection Model Using Improved Generalized Entropy and DNN
11
作者 Yanhua Liu Yuting Han +3 位作者 HuiChen Baokang Zhao XiaofengWang Ximeng Liu 《Computers, Materials & Continua》 SCIE EI 2024年第8期1851-1866,共16页
As the scale of the networks continually expands,the detection of distributed denial of service(DDoS)attacks has become increasingly vital.We propose an intelligent detection model named IGED by using improved general... As the scale of the networks continually expands,the detection of distributed denial of service(DDoS)attacks has become increasingly vital.We propose an intelligent detection model named IGED by using improved generalized entropy and deep neural network(DNN).The initial detection is based on improved generalized entropy to filter out as much normal traffic as possible,thereby reducing data volume.Then the fine detection is based on DNN to perform precise DDoS detection on the filtered suspicious traffic,enhancing the neural network’s generalization capabilities.Experimental results show that the proposed method can efficiently distinguish normal traffic from DDoS traffic.Compared with the benchmark methods,our method reaches 99.9%on low-rate DDoS(LDDoS),flooded DDoS and CICDDoS2019 datasets in terms of both accuracy and efficiency in identifying attack flows while reducing the time by 17%,31%and 8%. 展开更多
关键词 DDOS REAL-TIME improved generalized entropy DNN
下载PDF
Rare-earth Magnet Free Flux-switching Generator for Wind Turbines in Micro-grids:A Review
12
作者 Tugberk Ozmen BatıEren Ergun +1 位作者 Mehmet Onur Gulbahce Nevzat Onat 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第3期295-309,共15页
In traditional electricity generation plants,large powerful synchronous,induction,and direct current generators were used.With the proliferation of microgrids focused on electricity generation from renewable energy so... In traditional electricity generation plants,large powerful synchronous,induction,and direct current generators were used.With the proliferation of microgrids focused on electricity generation from renewable energy sources in today’s power grids,studies have been conducted on different types of generators.Instead of the traditional generator architecture,generators with brushless structures,particularly those utilizing magnets for excitation,have found broad applications.Fluxswitching generators(FSGs)are innovative types owing to their robust structure,active stator design,and high power density capabilities.However,designs have typically relied on rare-earth element magnets.Rare-earth magnets possess negative characteristics such as price uncertainty,the potential risk of scarcity in the future,and limited geographical production,leading to research on FSGs that do not depend on rare-earth magnets.This study comprehensively examines FSGs that do not use rare-earth element magnets.The study delves into the usage areas,operational mechanisms,structural diversities,and counterparts in the literature of these generators. 展开更多
关键词 FLUX-SWITCHING generATOR MICRO-GRID Wind energy
下载PDF
Necessary and Sufficient Conditions for Oscillations of the Generalized Liénard Systems
13
作者 Hongtao Zhang Xiaolin Liu Ping Yan 《Applied Mathematics》 2024年第6期391-405,共15页
In this paper, we study the second-order nonlinear differential systems of Liénard-type x˙=1a(x)[ h(y)−F(x) ], y˙=−a(x)g(x). Necessary and sufficient conditions to ensure that all nontrivial solutions are oscil... In this paper, we study the second-order nonlinear differential systems of Liénard-type x˙=1a(x)[ h(y)−F(x) ], y˙=−a(x)g(x). Necessary and sufficient conditions to ensure that all nontrivial solutions are oscillatory are established by using a new nonlinear integral inequality. Our results substantially extend and improve previous results known in the literature. 展开更多
关键词 generalized Liénard System Nonlinear Integral Inequality OSCILLATION
下载PDF
General multi-attack detection for continuous-variable quantum key distribution with local local oscillator
14
作者 康茁 刘维琪 +1 位作者 齐锦 贺晨 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期255-262,共8页
Continuous-variable quantum key distribution with a local local oscillator(LLO CVQKD)has been extensively researched due to its simplicity and security.For practical security of an LLO CVQKD system,there are two main ... Continuous-variable quantum key distribution with a local local oscillator(LLO CVQKD)has been extensively researched due to its simplicity and security.For practical security of an LLO CVQKD system,there are two main attack modes referred to as reference pulse attack and polarization attack presently.However,there is currently no general defense strategy against such attacks,and the security of the system needs further investigation.Here,we employ a deep learning framework called generative adversarial networks(GANs)to detect both attacks.We first analyze the data in different cases,derive a feature vector as input to a GAN model,and then show the training and testing process of the GAN model for attack classification.The proposed model has two parts,a discriminator and a generator,both of which employ a convolutional neural network(CNN)to improve accuracy.Simulation results show that the proposed scheme can detect and classify attacks without reducing the secret key rate and the maximum transmission distance.It only establishes a detection model by monitoring features of the pulse without adding additional devices. 展开更多
关键词 CVQKD generative adversarial network attack classification
下载PDF
EDU-GAN:Edge Enhancement Generative Adversarial Networks with Dual-Domain Discriminators for Inscription Images Denoising
15
作者 Yunjing Liu Erhu Zhang +2 位作者 Jingjing Wang Guangfeng Lin Jinghong Duan 《Computers, Materials & Continua》 SCIE EI 2024年第7期1633-1653,共21页
Recovering high-quality inscription images from unknown and complex inscription noisy images is a challenging research issue.Different fromnatural images,character images pay more attention to stroke information.Howev... Recovering high-quality inscription images from unknown and complex inscription noisy images is a challenging research issue.Different fromnatural images,character images pay more attention to stroke information.However,existingmodelsmainly consider pixel-level informationwhile ignoring structural information of the character,such as its edge and glyph,resulting in reconstructed images with mottled local structure and character damage.To solve these problems,we propose a novel generative adversarial network(GAN)framework based on an edge-guided generator and a discriminator constructed by a dual-domain U-Net framework,i.e.,EDU-GAN.Unlike existing frameworks,the generator introduces the edge extractionmodule,guiding it into the denoising process through the attention mechanism,which maintains the edge detail of the restored inscription image.Moreover,a dual-domain U-Net-based discriminator is proposed to learn the global and local discrepancy between the denoised and the label images in both image and morphological domains,which is helpful to blind denoising tasks.The proposed dual-domain discriminator and generator for adversarial training can reduce local artifacts and keep the denoised character structure intact.Due to the lack of a real-inscription image,we built the real-inscription dataset to provide an effective benchmark for studying inscription image denoising.The experimental results show the superiority of our method both in the synthetic and real-inscription datasets. 展开更多
关键词 Dual-domain discriminators inscription images DENOISING edge-guided generator
下载PDF
A Coordinate-Free Approach to the Design of Generalized Griffis-Duffy Platforms
16
作者 Chengwei Shen Xu Pei +1 位作者 Lubin Hang Jingjun Yu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第3期95-103,共9页
Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes uncontrollable.PMs remaining permanently in a singularity are beneficial... Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes uncontrollable.PMs remaining permanently in a singularity are beneficial for linearto-rotary motion conversion.Griffis-Duffy(GD)platform is a mobile structure admitting a Bricard motion.In this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed base.The generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same constraints.Owing to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD platform.Moreover,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis. 展开更多
关键词 generalized Griffis-Duffy platforms SELF-MOTION INVERSION Coordinate-free determination Manipulator design
下载PDF
Numerical Study on the Effect of Vortex Generators on the Aerodynamic Drag of a High-Speed Train
17
作者 Tian Li Hao Liang +1 位作者 Zerui Xiang Jiye Zhang 《Fluid Dynamics & Materials Processing》 EI 2024年第2期463-473,共11页
A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains.Using the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator typ... A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains.Using the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator types on the aerodynamic characteristics of an ICE2(Inter-city Electricity)train has been investigated.The results indi-cate that the vortex generators with wider triangle,trapezoid,and micro-ramp arranged on the surface of the tail car can significantly change the distribution of surface pressure and affect the vorticity intensity in the wake.This alteration effectively reduces the resistance of the tail car.Meanwhile,the micro-ramp vortex generator with its convergent structure at the rear exhibits enhancedflow-guiding capabilities,resulting in a 15.4%reduction in the drag of the tail car. 展开更多
关键词 Vortex generator aerodynamic drag REDUCTION numerical simulation
下载PDF
A generalization of Banach's lemma and its applications to perturbations of bounded linear operators
18
作者 WANG Zi DING Jiu WANG Yu-wen 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第2期363-369,共7页
Let X be a Banach space and let P:X→X be a bounded linear operator.Using an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear ... Let X be a Banach space and let P:X→X be a bounded linear operator.Using an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear operator on X,and a bound on its spectral radius is also obtained.This generalizes the classic Banach lemma.We apply the result to the perturbation analysis of general bounded linear operators on X with commutative perturbations. 展开更多
关键词 Banach lemma spectral radius generalized inverse perturbation analysis
下载PDF
Generalized load graphical forecasting method based on modal decomposition
19
作者 Lizhen Wu Peixin Chang +1 位作者 Wei Chen Tingting Pei 《Global Energy Interconnection》 EI CSCD 2024年第2期166-178,共13页
In a“low-carbon”context,the power load is affected by the coupling of multiple factors,which gradually evolves from the traditional“pure load”to the generalized load with the dual characteristics of“load+power su... In a“low-carbon”context,the power load is affected by the coupling of multiple factors,which gradually evolves from the traditional“pure load”to the generalized load with the dual characteristics of“load+power supply.”Traditional time-series forecasting methods are no longer suitable owing to the complexity and uncertainty associated with generalized loads.From the perspective of image processing,this study proposes a graphical short-term prediction method for generalized loads based on modal decomposition.First,the datasets are normalized and feature-filtered by comparing the results of Xtreme gradient boosting,gradient boosted decision tree,and random forest algorithms.Subsequently,the generalized load data are decomposed into three sets of modalities by modal decomposition,and red,green,and blue(RGB)images are generated using them as the pixel values of the R,G,and B channels.The generated images are diversified,and an optimized DenseNet neural network was used for training and prediction.Finally,the base load,wind power,and photovoltaic power generation data are selected,and the characteristic curves of the generalized load scenarios under different permeabilities of wind power and photovoltaic power generation are obtained using the density-based spatial clustering of applications with noise algorithm.Based on the proposed graphical forecasting method,the feasibility of the generalized load graphical forecasting method is verified by comparing it with the traditional time-series forecasting method. 展开更多
关键词 Load forecasting generalized load Image processing DenseNet Modal decomposition
下载PDF
Image segmentation of exfoliated two-dimensional materials by generative adversarial network-based data augmentation
20
作者 程晓昱 解晨雪 +6 位作者 刘宇伦 白瑞雪 肖南海 任琰博 张喜林 马惠 蒋崇云 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期112-117,共6页
Mechanically cleaved two-dimensional materials are random in size and thickness.Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production.Deep learning algorithms have b... Mechanically cleaved two-dimensional materials are random in size and thickness.Recognizing atomically thin flakes by human experts is inefficient and unsuitable for scalable production.Deep learning algorithms have been adopted as an alternative,nevertheless a major challenge is a lack of sufficient actual training images.Here we report the generation of synthetic two-dimensional materials images using StyleGAN3 to complement the dataset.DeepLabv3Plus network is trained with the synthetic images which reduces overfitting and improves recognition accuracy to over 90%.A semi-supervisory technique for labeling images is introduced to reduce manual efforts.The sharper edges recognized by this method facilitate material stacking with precise edge alignment,which benefits exploring novel properties of layered-material devices that crucially depend on the interlayer twist-angle.This feasible and efficient method allows for the rapid and high-quality manufacturing of atomically thin materials and devices. 展开更多
关键词 two-dimensional materials deep learning data augmentation generating adversarial networks
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部