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Designing a Protection Scheme in Micro-Grid Systems with DG Using Central Protection Unite and Multiple Setting Group Protection Relays
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作者 Mostafa I. Saleh Gaber El-Saady +1 位作者 Ali M. Yousef El-Noby A. Ibrahim 《Journal of Power and Energy Engineering》 2024年第9期37-49,共13页
Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this... Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains. 展开更多
关键词 Directional Overcurrent Relay Protection Coordination Distributed generators Central Protection Unite multiple Setting Group Protection Relay
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Dynamic weighted voting for multiple classifier fusion:a generalized rough set method 被引量:9
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作者 Sun Liang Han Chongzhao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第3期487-494,共8页
To improve the performance of multiple classifier system, a knowledge discovery based dynamic weighted voting (KD-DWV) is proposed based on knowledge discovery. In the method, all base classifiers may be allowed to ... To improve the performance of multiple classifier system, a knowledge discovery based dynamic weighted voting (KD-DWV) is proposed based on knowledge discovery. In the method, all base classifiers may be allowed to operate in different measurement/feature spaces to make the most of diverse classification information. The weights assigned to each output of a base classifier are estimated by the separability of training sample sets in relevant feature space. For this purpose, some decision tables (DTs) are established in terms of the diverse feature sets. And then the uncertainty measures of the separability are induced, in the form of mass functions in Dempster-Shafer theory (DST), from each DTs based on generalized rough set model. From the mass functions, all the weights are calculated by a modified heuristic fusion function and assigned dynamically to each classifier varying with its output. The comparison experiment is performed on the hyperspectral remote sensing images. And the experimental results show that the performance of the classification can be improved by using the proposed method compared with the plurality voting (PV). 展开更多
关键词 multiple classifier fusion dynamic weighted voting generalized rough set hyperspectral.
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Generalized multiple time windows model based parallel machine scheduling for TDRSS 被引量:1
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作者 LIN Peng KUANG Lin-ling +3 位作者 CHEN Xiang YAN Jian LU Jian-hua WANG Xiao-juan 《Journal of Beijing Institute of Technology》 EI CAS 2016年第3期382-391,共10页
The scheduling efficiency of the tracking and data relay satellite system(TDRSS)is strictly limited by the scheduling degrees of freedom(DoF),including time DoF defined by jobs' flexible time windows and spatial ... The scheduling efficiency of the tracking and data relay satellite system(TDRSS)is strictly limited by the scheduling degrees of freedom(DoF),including time DoF defined by jobs' flexible time windows and spatial DoF brought by multiple servable tracking and data relay satellites(TDRSs).In this paper,ageneralized multiple time windows(GMTW)model is proposed to fully exploit the time and spatial DoF.Then,the improvements of service capability and job-completion probability based on the GMTW are theoretically proved.Further,an asymmetric path-relinking(APR)based heuristic job scheduling framework is presented to maximize the usage of DoF provided by the GMTW.Simulation results show that by using our proposal 11%improvement of average jobcompletion probability can be obtained.Meanwhile,the computing time of the time-to-target can be shorten to 1/9 of the GRASP. 展开更多
关键词 parallel machine scheduling problem with generalized multiple time windows (PMGMTW) positive/negative adaptive subsequence adjustment (p/n-ASA) evolutionary asymmetric key-path-relinking (EvAKPR)
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Multiple attractors and generalized synchronization in delayed Mackey-Glass systems
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作者 李栋 郑志刚 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第11期4009-4013,共5页
Nonlinear dynamics of the time-delayed Mackey-Glass systems is explored. Coexistent multiple chaotic attractors are found. Attractors with double-scroll structures can be well classified in terms of different return t... Nonlinear dynamics of the time-delayed Mackey-Glass systems is explored. Coexistent multiple chaotic attractors are found. Attractors with double-scroll structures can be well classified in terms of different return times within one period of the delay time by constructing the Poincare section. Synchronizations of the drive-response Mackey-Glass oscillators are investigated. The critical coupling strength for the emergence of generalized synchronization against the delay time exhibits the interesting resonant behaviour. We reveal that stronger resonance effect may be observed when different attractors are applied to the drivers, i.e., more resonance peaks can be found. 展开更多
关键词 time-delayed Mackey-Glass system multiple chaotic attractors return numbers generalized synchronization
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Using Multiple Risk Factors and Generalized Linear Mixed Models with 5-Fold Cross-Validation Strategy for Optimal Carotid Plaque Progression Prediction
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作者 Qingyu Wang Dalin Tang +5 位作者 Liang Wang Gador Canton Zheyang Wu Thomas SHatsukami Kristen L Billiar Chun Yuan 《医用生物力学》 EI CAS CSCD 北大核心 2019年第A01期74-75,共2页
Background Cardiovascular diseases are closely linked to atherosclerotic plaque development and rupture.Plaque progression prediction is of fundamental significance to cardiovascular research and disease diagnosis,pre... Background Cardiovascular diseases are closely linked to atherosclerotic plaque development and rupture.Plaque progression prediction is of fundamental significance to cardiovascular research and disease diagnosis,prevention,and treatment.Generalized linear mixed models(GLMM)is an extension of linear model for categorical responses while considering the correlation among observations.Methods Magnetic resonance image(MRI)data of carotid atheroscleroticplaques were acquired from 20 patients with consent obtained and 3D thin-layer models were constructed to calculate plaque stress and strain for plaque progression prediction.Data for ten morphological and biomechanical risk factors included wall thickness(WT),lipid percent(LP),minimum cap thickness(MinCT),plaque area(PA),plaque burden(PB),lumen area(LA),maximum plaque wall stress(MPWS),maximum plaque wall strain(MPWSn),average plaque wall stress(APWS),and average plaque wall strain(APWSn)were extracted from all slices for analysis.Wall thickness increase(WTI),plaque burden increase(PBI)and plaque area increase(PAI) were chosen as three measures for plaque progression.Generalized linear mixed models(GLMM)with 5-fold cross-validation strategy were used to calculate prediction accuracy for each predictor and identify optimal predictor with the highest prediction accuracy defined as sum of sensitivity and specificity.All 201 MRI slices were randomly divided into 4 training subgroups and 1 verification subgroup.The training subgroups were used for model fitting,and the verification subgroup was used to estimate the model.All combinations(total1023)of 10 risk factors were feed to GLMM and the prediction accuracy of each predictor were selected from the point on the ROC(receiver operating characteristic)curve with the highest sum of specificity and sensitivity.Results LA was the best single predictor for PBI with the highest prediction accuracy(1.360 1),and the area under of the ROC curve(AUC)is0.654 0,followed by APWSn(1.336 3)with AUC=0.6342.The optimal predictor among all possible combinations for PBI was the combination of LA,PA,LP,WT,MPWS and MPWSn with prediction accuracy=1.414 6(AUC=0.715 8).LA was once again the best single predictor for PAI with the highest prediction accuracy(1.184 6)with AUC=0.606 4,followed by MPWSn(1. 183 2)with AUC=0.6084.The combination of PA,PB,WT,MPWS,MPWSn and APWSn gave the best prediction accuracy(1.302 5)for PAI,and the AUC value is 0.6657.PA was the best single predictor for WTI with highest prediction accuracy(1.288 7)with AUC=0.641 5,followed by WT(1.254 0),with AUC=0.6097.The combination of PA,PB,WT,LP,MinCT,MPWS and MPWS was the best predictor for WTI with prediction accuracy as 1.314 0,with AUC=0.6552.This indicated that PBI was a more predictable measure than WTI and PAI. The combinational predictors improved prediction accuracy by 9.95%,4.01%and 1.96%over the best single predictors for PAI,PBI and WTI(AUC values improved by9.78%,9.45%,and 2.14%),respectively.Conclusions The use of GLMM with 5-fold cross-validation strategy combining both morphological and biomechanical risk factors could potentially improve the accuracy of carotid plaque progression prediction.This study suggests that a linear combination of multiple predictors can provide potential improvement to existing plaque assessment schemes. 展开更多
关键词 multiple Risk FACTORS generalized Linear 5-Fold Cross-Validation STRATEGY AUC
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Near-field multiple super-resolution imaging from Mikaelian lens to generalized Maxwell's fish-eye lens
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作者 Yangyang Zhou Huanyang Chen 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第10期153-158,共6页
Super-resolution imaging is vital for optical applications, such as high capacity information transmission, real-time bio-molecular imaging, and nanolithography. In recent years, technologies and methods of super-reso... Super-resolution imaging is vital for optical applications, such as high capacity information transmission, real-time bio-molecular imaging, and nanolithography. In recent years, technologies and methods of super-resolution imaging have attracted much attention. Different kinds of novel lenses, from the superlens to the super-oscillatory lens, have been designed and fabricated to break through the diffraction limit. However, the effect of the super-resolution imaging in these lenses is not satisfactory due to intrinsic loss, aberration, large sidebands, and so on. Moreover, these lenses also cannot realize multiple super-resolution imaging. In this research, we introduce the solid immersion mechanism to Mikaelian lens(ML) for multiple super-resolution imaging. The effect is robust and valid for broadband frequencies. Based on conformal transformation optics as a bridge linking the solid immersion ML and generalized Maxwell's fish-eye lens(GMFEL), we also discovered the effect of multiple super-resolution imaging in the solid immersion GMFEL. 展开更多
关键词 multiple super-resolution imaging Mikaelian lens generalized Maxwell's fish-eye lens conformal transformation optics
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Distributed Control of Multiple-Bus Microgrid With Paralleled Distributed Generators 被引量:4
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作者 Bo Fan Jiangkai Peng +2 位作者 Jiajun Duan Qinmin Yang Wenxin Liu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2019年第3期676-684,共9页
A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed.In this paper, a distributed, two-level... A microgrid is hard to control due to its reduced inertia and increased uncertainties. To overcome the challenges of microgrid control, advanced controllers need to be developed.In this paper, a distributed, two-level, communication-economic control scheme is presented for multiple-bus microgrids with each bus having multiple distributed generators(DGs) connected in parallel. The control objective of the upper level is to calculate the voltage references for one-bus subsystems. The objectives of the lower control level are to make the subsystems' bus voltages track the voltage references and to enhance load current sharing accuracy among the local DGs. Firstly, a distributed consensusbased power sharing algorithm is introduced to determine the power generations of the subsystems. Secondly, a discrete-time droop equation is used to adjust subsystem frequencies for voltage reference calculations. Finally, a Lyapunov-based decentralized control algorithm is designed for bus voltage regulation and proportional load current sharing. Extensive simulation studies with microgrid models of different levels of detail are performed to demonstrate the merits of the proposed control scheme. 展开更多
关键词 COORDINATE CONTROL DECENTRALIZED CONTROL multiple-bus MICROGRID paralleled distributed generations power sharing algorithm
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Application of Multiple Mean Generational Function Method to Typhoon Prediction over the Western North Pacific
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作者 Qing Chen Shuyun Yang +1 位作者 Yufang Liao Nengjin Chen 《Meteorological and Environmental Research》 CAS 2013年第4期26-28,共3页
[ Objective] The multiple mean generational function (MMGF) method was applied to forecast the annual number of typhoons (TYs) over the Western North Pacific (WNP). [Method]The method yields a number of predicto... [ Objective] The multiple mean generational function (MMGF) method was applied to forecast the annual number of typhoons (TYs) over the Western North Pacific (WNP). [Method]The method yields a number of predictors by mean generational function based on the rolling 50- year data of TYs frequency and sunspot number, and was repeated to generate forecasts year after year by optimal subset regression. [ Result] The results showed a reasonably high predictive ability dudng period 2000 -2010, with an average root mean square (RMSE) value of 1.92 and a mean absolute error (MAE) value of 1.64. [ Conclusion] Although the MMGF method needs further validation in the practical operation, it already has strong potential for the improvement of skill at forecasting annual frequency of TYs in the WNP. 展开更多
关键词 TYPHOONS multiple mean generational function PREDICTION China
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QTL mapping for fiber quality and yieldrelated traits across multiple generations in segregating population of CCRI 70 被引量:3
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作者 DENG Xiaoying GONG Juwu +7 位作者 LIU Aiying SHI Yuzhen GONG Wankui GE Qun LI Junwen SHANG Haihong WU Yuxiang YUAN Youlu 《Journal of Cotton Research》 2019年第2期112-121,共10页
Background:Cotton is a significant economic crop that plays an indispensable role in many domains.Gossypium hirsutum L.is the most important fiber crop worldwide and contributes to more than 95%of global cotto n produ... Background:Cotton is a significant economic crop that plays an indispensable role in many domains.Gossypium hirsutum L.is the most important fiber crop worldwide and contributes to more than 95%of global cotto n production.Identifying stable quantitative trait locus(QTLs)controlling fiber quality and yield related traits are necessary prerequisites for marker-assisted selection(MAS).Results:A genetic linkage map was constructed with 312 simple sequence repeat(SSR)loci and 35 linkage groups using JoinMap 4.0;the map spanned 1 929.9 cM,with an average interval between two markers of 6.19 cM,and covered approximately 43.37%of the cotton genome.A total of 74 QTLs controlling fiber quality and 41 QTLs controlling yield-related traits were identified in 4 segregating generations.These QTLs were distributed across 20 chromosomes and collectively explained 1.01%?27.80%of the observed phenotypic variations.In particular,35 stable QTLs could be identified in multiple generations,25 common QTLs were con sistent with those in previous studies,and 15 QTL clusters were found in 11 chromosome segments.Conclusion:These studies provide a theoretical basis for improving cotton yield and fiber quality for molecular marker-assisted selection. 展开更多
关键词 QTL mapping Fiber quality Yield QUALITY multiple generations UPLAND cotton(Gossypium hirsutum L.)
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Emotional dialog generation via multiple classifiers based on a generative adversarial network
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作者 Wei CHEN Xinmiao CHEN Xiao SUN 《Virtual Reality & Intelligent Hardware》 2021年第1期18-32,共15页
Background Human-machine dialog generation is an essential topic of research in the field of natural language processing.Generating high-quality,diverse,fluent,and emotional conversation is a challenging task.Based on... Background Human-machine dialog generation is an essential topic of research in the field of natural language processing.Generating high-quality,diverse,fluent,and emotional conversation is a challenging task.Based on continuing advancements in artificial intelligence and deep learning,new methods have come to the forefront in recent times.In particular,the end-to-end neural network model provides an extensible conversation generation framework that has the potential to enable machines to understand semantics and automatically generate responses.However,neural network models come with their own set of questions and challenges.The basic conversational model framework tends to produce universal,meaningless,and relatively"safe"answers.Methods Based on generative adversarial networks(GANs),a new emotional dialog generation framework called EMC-GAN is proposed in this study to address the task of emotional dialog generation.The proposed model comprises a generative and three discriminative models.The generator is based on the basic sequence-to-sequence(Seq2Seq)dialog generation model,and the aggregate discriminative model for the overall framework consists of a basic discriminative model,an emotion discriminative model,and a fluency discriminative model.The basic discriminative model distinguishes generated fake sentences from real sentences in the training corpus.The emotion discriminative model evaluates whether the emotion conveyed via the generated dialog agrees with a pre-specified emotion,and directs the generative model to generate dialogs that correspond to the category of the pre-specified emotion.Finally,the fluency discriminative model assigns a score to the fluency of the generated dialog and guides the generator to produce more fluent sentences.Results Based on the experimental results,this study confirms the superiority of the proposed model over similar existing models with respect to emotional accuracy,fluency,and consistency.Conclusions The proposed EMC-GAN model is capable of generating consistent,smooth,and fluent dialog that conveys pre-specified emotions,and exhibits better performance with respect to emotional accuracy,consistency,and fluency compared to its competitors. 展开更多
关键词 Emotional dialog generation Sequence-to-sequence model Emotion classification generative adversarial networks multiple classifiers
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Characterization of hot carrier cooling and multiple exciton generation dynamics in PbS QDs using an improved transient grating technique
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作者 Qing Shen Kenji Katayama Taro Toyoda 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2015年第6期712-716,共5页
Multiple exciton generation (MEG) dynamics in colloidal PbS quantum dots (QDs) characterized with an im- proved transient grating (TG) technique will be reported. Only one peak soon after optical absorption and ... Multiple exciton generation (MEG) dynamics in colloidal PbS quantum dots (QDs) characterized with an im- proved transient grating (TG) technique will be reported. Only one peak soon after optical absorption and a fast decay within 1 ps can be observed in the TG kinetics when the photon energy of the pump light hv is smaller than 2.7Eg (Eg: band gap between LUMO and HOMO in the QDs), which corresponds to hot carrier cooling. When hv is greater than 2.7Eg, however, after the initial peak, the TG signal decreases first and soon increases, and then a new peak appears at about 2 to 3 ps. The initial peak and the new peak correspond to hot carriers at the higher excited state and MEG at the lowest excited state, respectively. By proposing a theoretical model, we can calculate the hot carrier cooling time constant and MEG occurrence time constant quantitatively. When MEG does not happen for hv smaller than 2.7Eg, hot carrier cools with a time con- stant of 400 fs. When MEG occurs for hv larger than 2.7Eg, hot carrier cools with a time constant as small as 200 fs, while MEG occurs with a time constant of 600 fs. The detailed hot carrier cooling and MEG occurrence dynamics characterized in this work would shed light on the further understanding of MEG mechanism of various type of semiconductor QDs. 展开更多
关键词 PbS Quantum dots multiple exciton generation Hot carrier cooling Transient grating
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Automatic Generation of Multiple-Choice Items for Prepositions Based on Word2vec
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作者 Wenyan Xiao Mingwen Wang +2 位作者 Chenlin Zhang Yiming Tan Zhiming Chen 《国际计算机前沿大会会议论文集》 2018年第2期8-8,共1页
关键词 multiple-choice ITEM AUTOMATIC generATION Word2vec
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Optimizing Packet Generation Rate for Multiple Hops WBAN with CSMA/CA Based on IEEE802.15.6
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作者 Pham Thanh Hiep Ryuji Kohno 《Communications and Network》 2014年第2期112-123,共12页
Wireless Body Area Network (WBAN) is considered to apply to both medical healthcare and entertainment applications. A requirement for each application is different, i.e. high reliability for medical healthcare whereas... Wireless Body Area Network (WBAN) is considered to apply to both medical healthcare and entertainment applications. A requirement for each application is different, i.e. high reliability for medical healthcare whereas high throughput for entertainment application. However, for both applications, low energy consumption is requested. Multiple hops technics have been researching in many fields of wireless system, e.g., ad hod, mobile, ITS etc. and its energy-efficiency is reported to be high. We propose the multiple hops technic for WBAN, however, WBAN is different to another systems, almost sensors forward the vital data packet of another sensors while sensing and generating the data packet of itself. Therefore, according to a packet generation rate of all sensors, probabilities of successful transmission and packet loss because of collision, timeout and overflow, are changed. It means that the vital data is lost and the transmit power is wasted due to packet loss. In order to obtain the highest throughput and save the power, the successful transmission probability is analyzed and the packet generation rate is optimized for multiple hops WBAN that using CSMA/CA based on IEEE802.15.6. The numerical calculation result indicates that the optimized packet generation rate depends on the system model. Moreover, the relation between the system model, the optimized packet generation rate and the throughput is discussed in the paper. 展开更多
关键词 multiple HOPS Body Area Network Optimal PACKET generation Rate Successful PROBABILITY COLLISION PROBABILITY CSMA/CA of IEEE802.15.6
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Knowledge discovery method for feature-decision level fusion of multiple classifiers 被引量:1
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作者 孙亮 韩崇昭 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期222-227,共6页
To improve the performance of the multiple classifier system, a new method of feature-decision level fusion is proposed based on knowledge discovery. In the new method, the base classifiers operate on different featur... To improve the performance of the multiple classifier system, a new method of feature-decision level fusion is proposed based on knowledge discovery. In the new method, the base classifiers operate on different feature spaces and their types depend on different measures of between-class separability. The uncertainty measures corresponding to each output of each base classifier are induced from the established decision tables (DTs) in the form of mass function in the Dempster-Shafer theory (DST). Furthermore, an effective fusion framework is built at the feature-decision level on the basis of a generalized rough set model and the DST. The experiment for the classification of hyperspectral remote sensing images shows that the performance of the classification can be improved by the proposed method compared with that of plurality voting (PV). 展开更多
关键词 multiple classifier fusion knowledge discovery Dempster-Shafer theory generalized rough set HYPERSPECTRAL
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Nonlinear Decoupling PID Control Using Neural Networks and Multiple Models 被引量:8
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作者 Lianfei ZHAI Tianyou CHAI 《控制理论与应用(英文版)》 EI 2006年第1期62-69,共8页
For a class of complex industrial processes with strong nonlinearity, serious coupling and uncertainty, a nonlinear decoupling proportional-integral-differential (PID) controller is proposed, which consists of a tra... For a class of complex industrial processes with strong nonlinearity, serious coupling and uncertainty, a nonlinear decoupling proportional-integral-differential (PID) controller is proposed, which consists of a traditional PID controller, a decoupling compensator and a feedforward compensator for the unmodeled dynamics. The parameters of such controller is selected based on the generalized minimum variance control law. The unmodeled dynamics is estimated and compensated by neural networks, a switching mechanism is introduced to improve tracking performance, then a nonlinear decoupling PID control algorithm is proposed. All signals in such switching system are globally bounded and the tracking error is convergent. Simulations show effectiveness of the algorithm. 展开更多
关键词 NONLINEAR Decoupling control PID Neural networks multiple models generalized minimum variance
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Band structure calculation of scalar waves in two-dimensional phononic crystals based on generalized multipole technique 被引量:4
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作者 史志杰 汪越胜 张传增 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第9期1123-1144,共22页
A multiple monopole (or multipole) method based on the generalized mul- tipole technique (GMT) is proposed to calculate the band structures of scalar waves in two-dimensional phononic crystals which are composed o... A multiple monopole (or multipole) method based on the generalized mul- tipole technique (GMT) is proposed to calculate the band structures of scalar waves in two-dimensional phononic crystals which are composed of arbitrarily shaped cylinders embedded in a host medium. In order to find the eigenvalues of the problem, besides the sources used to expand the wave field, an extra monopole source is introduced which acts as the external excitation. By varying the frequency of the excitation, the eigenvalues can be localized as the extreme points of an appropriately chosen function. By sweeping the frequency range of interest and sweeping the boundary of the irreducible first Brillouin zone, the band structure is obtained. Some numerical examples are presented to validate the proposed method. 展开更多
关键词 phononic crystal generalized multipole technique multiple multipolemethod multiple monopole method band structure eigenvalue problem
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Refined Jensen-Based Multiple Integral Inequality and Its Application to Stability of Time-Delay Systems 被引量:5
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作者 Jidong Wang Zhanshan Wang +1 位作者 Sanbo Ding Huaguang Zhang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第3期758-764,共7页
This paper investigates the stability of time-delay systems via a multiple integral approach. Based on the refined Jensen-based inequality, a novel multiple integral inequality is proposed. Applying the multiple integ... This paper investigates the stability of time-delay systems via a multiple integral approach. Based on the refined Jensen-based inequality, a novel multiple integral inequality is proposed. Applying the multiple integral inequality to estimate the derivative of Lyapunov-Krasovskii functional(LKF) with multiple integral terms, a novel stability condition is formulated for the linear time-delay systems. Two numerical examples are employed to demonstrate the improvements of our results. 展开更多
关键词 multiple integral approach refined Jensen-based multiple integral inequality(RJMII) stability analysis time-delay systems
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MULTIPLE SOLUTIONS FOR NONAUTONOMOUS SECOND ORDER PERIODIC SYSTEMS 被引量:1
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作者 Zdzislaw Denkowski Leszek Gasiński Nikolaos S.Papageorgiou 《Acta Mathematica Scientia》 SCIE CSCD 2010年第1期350-358,共9页
We study nonautonomonus second order periodic systems with a nonslnooth potential. Using the nonsmooth critical theory, we establish the existence of at least two nontrivial solutions. Our framework incorporates large... We study nonautonomonus second order periodic systems with a nonslnooth potential. Using the nonsmooth critical theory, we establish the existence of at least two nontrivial solutions. Our framework incorporates large classes of both subquadratic and superquadratic potentials at infinity. 展开更多
关键词 locally Lipschitz potential generalized subdifferentiM coercive functional critical point local linking theorem nonsmooth Palais-Smale condition multiple nontrivial solutions
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Stability criteria for linear systems with multiple time-varying delays 被引量:1
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作者 Bugong XU(Laboratory of Real-Time Control Through Internet and Fieldbuses, College of Automation Science and Engineering, South China University of Technology, Guangzhou Guangdong 510640, China) 《控制理论与应用(英文版)》 EI 2003年第1期65-69,共5页
New delay-independent and delay-dependent stability criteria for linear systems with multiple time-varying delays are established by using the time-domain method. The results are derived based on a new-type stability ... New delay-independent and delay-dependent stability criteria for linear systems with multiple time-varying delays are established by using the time-domain method. The results are derived based on a new-type stability theorem for general retarded dynamical systems and new analysis techniques developed in the author's previous work. Unlike some results in the literature, all of the established results do not depend on the derivative of time-varying delays. Therefore, they are suitable for the case with very fast time-varying delays. In addition, some remarks are also given to explain the obtained results and to point out the limitations of the previous results in the literature. Keywords Stability - Delay-independent criteria - Delay-dependent criteria - Linear time-delay systems - Multiple time-varying delays This work was supported by NSFC Key-Project (No. 60334010) and Guangdong Province Natural Science Foundation of China (No. 31406). 展开更多
关键词 STABILITY Delay-independent criteria Delay-dependent criteria Linear time-delay systems multiple time-varying delays
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Accuracy of radar-based precipitation measurement: An analysis of the influence of multiple scattering and non-spherical particle shape 被引量:1
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作者 Hao Chen JinHu Wang +1 位作者 Ming Wei HongBin Chen 《Earth and Planetary Physics》 2018年第1期40-51,共12页
Two assumptions are typically made when radar echo signals from precipitation are analyzed to determine the micro-physical parameters of raindrops:(1) the raindrops are assumed to be spherical;(2) multiple scattering ... Two assumptions are typically made when radar echo signals from precipitation are analyzed to determine the micro-physical parameters of raindrops:(1) the raindrops are assumed to be spherical;(2) multiple scattering effects are ignored. Radar cross sections(RCS) are usually calculated using Rayleigh's scattering equation with the simple addition method in the radar meteorological equation.We investigate the extent to which consideration of the effects of multiple scattering and of the non-spherical shapes within actual raindrop swarms would result in RCS values significantly different from those obtained by conventional analytical methods. First, we establish spherical and non-spherical raindrop models, with Gamma, JD, JT, and MP size distributions, respectively. We then use XFDTD software to calculate the radar cross sections of the above raindrop models at the S, C, X and Ku radar bands. Our XFDTD results are then compared to RCS values calculated by the Rayleigh approximation with simple addition methods. We find that:(1) RCS values calculated using multiple scattering XFDTD software differ significantly from those calculated by the simple addition method at the same band for the same model. In particular, for the spherical raindrop models, the relative differences in RCS values between the methods range from a maximum of 89.649% to a minimum of 43.701%; for the non-spherical raindrop models, the relative differences range from a maximum of 85.868% to a minimum of 11.875%.(2) Our multiple scattering XFDTD results, compared to those obtained from the Rayleigh formula,again differ at all four size distributions, by relative errors of 169.522%, 37.176%, 216.455%, and 63.428%, respectively. When nonspherical effects are considered, differences in RCS values between our XFDTD calculations and Rayleigh calculations are smaller; at the above four size distributions the relative errors are 0.213%, 0.171%, 7.683%, and 44.514%, respectively. RCS values computed by considering multiple scattering and non-spherical particle shapes are larger than Rayleigh RCS results, at all of the above four size distributions; the relative errors between the two methods are 220.673%, 129.320%, 387.240%, and 186.613%, respectively. After changing the arrangement of particles at four size distributions in the case of multiple scattering effect and non-spherical effect, the RCS values of Arrangement 2 are smaller than those of Arrangement 1; the relative errors for Arrangement 2, compared to Rayleigh, are 60.558%, 76.263%, 85.941%,64.852%, respectively. We have demonstrated that multiple scattering, non-spherical particle shapes, and the arrangement within particle swarms all affect the calculation of RCS values. The largest influence appears to be that of the multiple scattering effect.Consideration of particle shapes appears to have the least influence on computed RCS values. We conclude that multiple scattering effects must be considered in practical meteorological detection. 展开更多
关键词 Finite difference time domain(FDTD) generalized LORENZ MIE theory raindrops RCS multiple scattering oblate ELLIPSOID particle
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