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Dynamic Constraint-Driven Event-Triggered Control of Strict-Feedback Systems Without Max/Min Values on Irregular Constraints
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作者 Zhuwu Shao Yujuan Wang +1 位作者 Zeqiang Li Yongduan Song 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期569-580,共12页
This work proposes an event-triggered adaptive control approach for a class of uncertain nonlinear systems under irregular constraints.Unlike the constraints considered in most existing papers,here the external irregu... This work proposes an event-triggered adaptive control approach for a class of uncertain nonlinear systems under irregular constraints.Unlike the constraints considered in most existing papers,here the external irregular constraints are considered and a constraints switching mechanism(CSM)is introduced to circumvent the difficulties arising from irregular output constraints.Based on the CSM,a new class of generalized barrier functions are constructed,which allows the control results to be independent of the maximum and minimum values(MMVs)of constraints and thus extends the existing results.Finally,we proposed a novel dynamic constraint-driven event-triggered strategy(DCDETS),under which the stress on signal transmission is reduced greatly and no constraints are violated by making a dynamic trade-off among system state,external constraints,and inter-execution intervals.It is proved that the system output is driven to close to the reference trajectory and the semi-global stability is guaranteed under the proposed control scheme,regardless of the external irregular output constraints.Simulation also verifies the effectiveness and benefits of the proposed method. 展开更多
关键词 Adaptive control dynamic constraint-driven event-triggered control irregular output constraints nonlinear strict-feed-back systems
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Irregular initial solidification by mold thermal monitoring in the continuous casting of steels:A review
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作者 Qiuping Li Guanghua Wen +3 位作者 Fuhang Chen Ping Tang Zibing Hou Xinyun Mo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期1003-1015,共13页
Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the ... Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the high-efficiency continuous casting of steels.The application of mold thermal monitoring(MTM) systems,which use thermocouples to detect and respond to temperature variations in molds,has become an effective method to address irregular initial solidification phenomena.Such systems are widely applied in numerous steel companies for sticker breakout prediction.However,monitoring the surface defects of strands remains immature.Hence,indepth research is necessary to utilize the potential advantages and comprehensive monitoring of MTM systems.This paper summarizes what is included in the irregular initial solidification phenomena and systematically reviews the current state of research on these phenomena by the MTM systems.Furthermore,the influences of mold slag behavior on monitoring these phenomena are analyzed.Finally,the remaining problems of the formation mechanisms and investigations of irregular initial solidification phenomena are discussed,and future research directions are proposed. 展开更多
关键词 irregular initial solidification mold thermal monitoring continuous casting mold slag THERMOCOUPLE
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Kneadable dough-type hydrogel transforming from dynamic to rigid network to repair irregular bone defects
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作者 Ningtao Wang Jie Chen +8 位作者 Yanyang Chen Liang Chen Luhan Bao Zhengmei Huang Xiaoyu Han Jiangkuo Lu Zhengwei Cai Wenguo Cui Zhengwei Huang 《Bioactive Materials》 SCIE CSCD 2024年第10期430-444,共15页
Irregular bone defects,characterized by unpredictable size,shape,and depth,pose a major challenge to clinical treatment.Although various bone grafts are available,none can fully meet the repair needs of the defective ... Irregular bone defects,characterized by unpredictable size,shape,and depth,pose a major challenge to clinical treatment.Although various bone grafts are available,none can fully meet the repair needs of the defective area.Here,this study fabricates a dough-type hydrogel(DR-Net),in which the first dynamic network is generated by coordination between thiol groups and silver ions,thereby possessing kneadability to adapt to various irregular bone defects.The second rigid covalent network is formed through photocrosslinking,maintaining the osteogenic space under external forces and achieving a better match with the bone regeneration process.In vitro,an irregular alveolar bone defect is established in the fresh porcine mandible,and the dough-type hydrogel exhibits outstanding shape adaptability,perfectly matching the morphology of the bone defect.After photocuring,the storage modulus of the hydrogel increases 8.6 times,from 3.7 kPa(before irradiation)to 32 kPa(after irradiation).Furthermore,this hydrogel enables effective loading of P24 peptide,which potently accelerates bone repair in Sprague–Dawley(SD)rats with critical calvarial defects.Overall,the dough-type hydrogel with kneadability,space-maintaining capability,and osteogenic activity exhibits exceptional potential for clinical translation in treating irregular bone defects. 展开更多
关键词 Kneadable Dough-type hydrogel Dynamic network Rigid network irregular bone defect
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Performance and Complexity Trade-Off between Short-Length Regular and Irregular LDPC
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作者 Ziyuan Peng Ruizhe Yang 《Journal of Computer and Communications》 2024年第9期208-215,共8页
In this paper, both the high-complexity near-ML list decoding and the low-complexity belief propagation decoding are tested for some well-known regular and irregular LDPC codes. The complexity and performance trade-of... In this paper, both the high-complexity near-ML list decoding and the low-complexity belief propagation decoding are tested for some well-known regular and irregular LDPC codes. The complexity and performance trade-off is shown clearly and demonstrated with the paradigm of hybrid decoding. For regular LDPC code, the SNR-threshold performance and error-floor performance could be improved to the optimal level of ML decoding if the decoding complexity is progressively increased, usually corresponding to the near-ML decoding with progressively increased size of list. For irregular LDPC code, the SNR-threshold performance and error-floor performance could only be improved to a bottle-neck even with unlimited decoding complexity. However, with the technique of CRC-aided hybrid decoding, the ML performance could be greatly improved and approached with reasonable complexity thanks to the improved code-weight distribution from the concatenation of CRC and irregular LDPC code. Finally, CRC-aided 5GNR-LDPC code is evaluated and the capacity-approaching capability is shown. 展开更多
关键词 Regular LDPC irregular LDPC Near-ML Decoding List Decoding Belief Propagation Algorithm Sum-Product Algorithm CRC-Aided Hybrid Decoding
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Design of Irregular QC-LDPC Code Based Multi-Level Coded Modulation Scheme for High Speed Optical Communication Systems 被引量:7
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作者 Liqian Wang Dongdong Wang +3 位作者 Yongjing Ni Xue Chen Midou Cui Fu Yang 《China Communications》 SCIE CSCD 2019年第5期106-120,共15页
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon... In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems. 展开更多
关键词 quasi-cyclic LOW-DENSITY parity check (QC-LDPC) code irregular extrinsic INFORMATION transfer(EXIT) chart generalized mutual information(GMI) MULTI-LEVEL coded modulation(MLCM)
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Seismic analysis of high-speed railway irregular bridge–track system considering V-shaped canyon effect 被引量:4
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作者 Zhihui Zhu Yongjiu Tang +2 位作者 Zhenning Ba Kun Wang Wei Gong 《Railway Engineering Science》 2022年第1期57-70,共14页
To explore the effect of canyon topography on the seismic response of railway irregular bridge-track system that crosses a V-shaped canyon, seismic ground motions of the horizontal site and V-shaped canyon site were s... To explore the effect of canyon topography on the seismic response of railway irregular bridge-track system that crosses a V-shaped canyon, seismic ground motions of the horizontal site and V-shaped canyon site were simulated through theoretical analysis with 12 earthquake records selected from the Pacific Earthquake Engineering Research Center(PEER) Strong Ground Motion Database matching the site condition of the bridge.Nonlinear seismic response analyses of an existing 11-span irregular simply supported railway bridge-track system were performed under the simulated spatially varying ground motions. The effects of the V-shaped canyon topography on the peak ground acceleration at bridge foundations and seismic responses of the bridge-track system were analyzed. Comparisons between the results of horizontal and V-shaped canyon sites show that the top relative displacement between adjacent piers at the junction of the incident side and the back side of the V-shaped site is almost two times that of the horizontal site, which also determines the seismic response of the fastener. The maximum displacement of the fastener occurs in the V-shaped canyon site and is 1.4 times larger than that in the horizontal site. Neglecting the effect of V-shaped canyon leads to the inappropriate assessment of the maximum seismic response of the irregular high-speed railway bridge-track system. Moreover, engineers should focus on the girder end to the left or right of the two fasteners within the distance of track seismic damage. 展开更多
关键词 V-shaped canyon Nonlinear seismic response irregular bridge Simply supported railway bridge Analytical solution Topography effect
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Deep learning-based fault diagnostic network of high-speed train secondary suspension systems for immunity to track irregularities and wheel wear 被引量:3
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作者 Yunguang Ye Ping Huang Yongxiang Zhang 《Railway Engineering Science》 2022年第1期96-116,共21页
Fault detection and isolation of high-speed train suspension systems is of critical importance to guarantee train running safety. Firstly, the existing methods concerning fault detection or isolation of train suspensi... Fault detection and isolation of high-speed train suspension systems is of critical importance to guarantee train running safety. Firstly, the existing methods concerning fault detection or isolation of train suspension systems are briefly reviewed and divided into two categories, i.e., model-based and data-driven approaches. The advantages and disadvantages of these two categories of approaches are briefly summarized. Secondly, a 1D convolution network-based fault diagnostic method for highspeed train suspension systems is designed. To improve the robustness of the method, a Gaussian white noise strategy(GWN-strategy) for immunity to track irregularities and an edge sample training strategy(EST-strategy) for immunity to wheel wear are proposed. The whole network is called GWN-EST-1 DCNN method. Thirdly, to show the performance of this method, a multibody dynamics simulation model of a high-speed train is built to generate the lateral acceleration of a bogie frame corresponding to different track irregularities, wheel profiles, and secondary suspension faults. The simulated signals are then inputted into the diagnostic network, and the results show the correctness and superiority of the GWN-EST-1DCNN method. Finally,the 1DCNN method is further validated using tracking data of a CRH3 train running on a high-speed railway line. 展开更多
关键词 High-speed train suspension system Fault diagnosis Track irregularities Wheel wear Deep learning Literature review
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Mei symmetry and conservation laws of discrete nonholonomic dynamical systems with regular and irregular lattices 被引量:1
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作者 赵纲领 陈立群 +1 位作者 傅景礼 洪方昱 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期50-56,共7页
In this paper,Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated.Firstly,the equations of motion of discrete nonholonomic systems are ... In this paper,Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated.Firstly,the equations of motion of discrete nonholonomic systems are introduced for regular and irregular lattices.Secondly,for cases of the two lattices,based on the invariance of the Hamiltomian functional under the infinitesimal transformation of time and generalized coordinates,we present the quasi-extremal equation,the discrete analogues of Noether identity,Noether theorems,and the Noether conservation laws of the systems.Thirdly,in cases of the two lattices,we study the Mei symmetry in which we give the discrete analogues of the criterion,the theorem,and the conservative laws of Mei symmetry for the systems.Finally,an example is discussed for the application of the results. 展开更多
关键词 regular and irregular lattice nonholonomic system Noether symmetry Mei symmetry
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An optimized finite difference method based on a polar coordinate system for regional-scale irregular topography 被引量:1
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作者 Jianxia Xu Wei Zhang Xiaofei Chen 《Earthquake Science》 2021年第4期334-343,共10页
The finite difference method(FDM)is an important numerical approach for simulating the propagation of seismic waves,and some FDMs can be used to study the impact of the Earth’s curvature and topography over large dis... The finite difference method(FDM)is an important numerical approach for simulating the propagation of seismic waves,and some FDMs can be used to study the impact of the Earth’s curvature and topography over large distances.To efficiently model the effects of the Earth’s irregular topography on the propagation of seismic waves,here we optimize a previously proposed grid mesh method and develop a novel two-dimensional boundary-conforming FDM based on a curvilinear polar coordinate system.This method efficiently simulates the propagation of seismic waves in an arc-shaped model with large variations in surface topography.Our method was benchmarked against other reported methods using several global-scale models.The consistency of the results confirms the validity of our proposed optimization strategy.Furthermore,our findings indicate that the proposed optimization strategy improves computational efficiency. 展开更多
关键词 finite difference irregular topography polar coordinate system.
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Strength and deformation characteristics of irregular columnar jointed rock mass: A combined experimental and theoretical study 被引量:2
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作者 Xiangcheng Que Zhende Zhu +2 位作者 Yanxin He Zihao Niu Haonan Huang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期429-441,共13页
The irregularity of jointed network poses a challenge to the determination of field mechanical param-eters of columnar jointed rock mass(CJRM),and a reasonable prediction of deformation and strength characteristics of... The irregularity of jointed network poses a challenge to the determination of field mechanical param-eters of columnar jointed rock mass(CJRM),and a reasonable prediction of deformation and strength characteristics of CJRM is important for engineering construction.The Voronoi diagram and three-dimensional printing technology were used to make an irregular columnar jointed mold,and the irregular CJRM(ICJRM)specimens with different dip directions and dip angles were prepared.Uniaxial compression tests were performed,and the anisotropic strength and deformation characteristics of ICJRM were described.The failure modes and mechanisms were revealed in accordance with the final appearances of the ICJRM specimens.Based on the model test results,the empirical correlations for determining the field deformation and strength parameters of CJRM were derived using the dip angle and modified joint factor.The proposed empirical equations were used in the Baihetan Project,and the calculated mechanical parameters were compared with the field test results and those obtained from the tunneling quality index method.Results showed that the deformation parameters determined by the two proposed methods are all consistent with the field test results,and these two methods can also estimate the strength parameters effectively. 展开更多
关键词 irregular columnar jointed rock mass (ICJRM) Physical model test Anisotropic characteristic Empirical relations Dip angle Modified joint factor
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Elastic simulation method in an irregular polar coordinate system
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作者 Yang Yu Ran Qi +3 位作者 Chen Kang Lei Cheng Zhang Yu-sheng Han Song 《Applied Geophysics》 SCIE CSCD 2022年第3期378-394,471,共18页
When simulating the propagation of seismic waves in some special structures,such as tunnels and boreholes,finite difference forward modeling in the polar system has higher accuracy than the traditional Cartesian syste... When simulating the propagation of seismic waves in some special structures,such as tunnels and boreholes,finite difference forward modeling in the polar system has higher accuracy than the traditional Cartesian system.In actual situations,the polar space is the most irregular.To solve this problem,a forward modeling method for an irregular polar coordinate system is proposed to improve the simulation accuracy.First,an irregular surface of the polar space was meshed into an irregular polar system.After the transformation,the undulating surface was mapped into a plane one,and the wavefield was then computed in an irregular polar system.The Lebedev staggered grid was used to solve the wave equations in the irregular polar system.In addition,the artificial absorption boundary,cylindrical free boundary,and circumferential boundary conditions were used to absorb the boundary reflection.We selected three polar space models to demonstrate the new method in this study.The results show that the proposed elastic simulation method in an irregular polar coordinate system can produce more accurate and stable simulation results when modeling seismic wave propagation in an irregular polar space.Elastic full waveform inversion further shows that the irregular polar system elastic simulation method can accurately simulate the wavefield in an undulating polar space. 展开更多
关键词 irregular polar system Elastic wave Lebedev staggered grid Polar coordinate system boundary conditions
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Irregularly red-cell antibody detection and subgroup typing of ABO,Rh systemsin donors of Shanghai-recently reports
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《中国输血杂志》 CAS CSCD 2001年第S1期363-,共1页
关键词 ABO RH irregularly red-cell antibody detection and subgroup typing of ABO Rh systemsin donors of Shanghai-recently reports cell
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A Class of Generalized Approximate Inverse Solvers for Unsymmetric Linear Systems of Irregular Structure Based on Adaptive Algorithmic Modelling for Solving Complex Computational Problems in Three Space Dimensions
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作者 Anastasia-Dimitra Lipitakis 《Applied Mathematics》 2016年第11期1225-1240,共17页
A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex... A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex computational problems in three space dimensions. The proposed class of approximate inverse is chosen as the basis to yield systems on which classic and preconditioned iterative methods are explicitly applied. Optimized versions of the proposed approximate inverse are presented using special storage (k-sweep) techniques leading to economical forms of the approximate inverses. Application of the adaptive algorithmic methodologies on a characteristic nonlinear boundary value problem is discussed and numerical results are given. 展开更多
关键词 Adaptive Algorithms Algorithmic Modelling Approximate Inverse Incomplete LU Factorization Approximate Decomposition Unsymmetric Linear systems Preconditioned Iterative Methods systems of irregular Structure
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Influence of Random Track Irregularities on Dynamic Response of Bridge/Track Structure/High-Speed Train Systems
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作者 Marian Klasztomy Monika Podwoma 《Journal of Civil Engineering and Architecture》 2014年第10期1335-1352,共18页
Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process... Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process. The study presents the results of numerical dynamic analysis of advanced virtual models of composite BTT (bridge/ballasted track structure/high-speed train) systems. The analysis has been conducted for a series of types of single-span simply-supported railway composite (steel-concrete) bridges, with a symmetric platform, located on lines with ballasted track structure adapted for high-speed trains. The bridges are designed according to Polish bridge standards. A new methodology of numerical modeling and simulation of dynamic processes in BTT systems has been applied. The methodology takes into consideration viscoelastic suspensions of rail-vehicles, nonlinear Hertz wheel-rail contact stiffness and one-side wheel-rail contact, physically nonlinear elastic-damping properties of the track structure, random vertical track irregularities, approach slabs and other features. Computer algorithms of FE (finite element) modeling and simulation were programmed in Delphi. Both static and dynamic numerical investigations of the bridges forming the series of types have been carried out. It has been proved that in the case of common structural solutions of bridges and ballasted track structures, it is necessary to put certain limitations on operating speeds, macadam ballast and vertical track roughness. 展开更多
关键词 Steel-concrete composite bridge ballasted track structure high-speed passenger train random vertical track irregularities numerical analysis.
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Generation of irregular particle packing with prescribed statistical distribution, spatial arrangement, and volume fraction
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作者 Libing Du Xinrong Liu +1 位作者 Yafeng Han Zhiyun Deng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期375-394,共20页
A method for packing irregular particles with a prescribed volume fraction is proposed.Furthermore,the generated granular material adheres to the prescribed statistical distribution and satisfies the desired complex s... A method for packing irregular particles with a prescribed volume fraction is proposed.Furthermore,the generated granular material adheres to the prescribed statistical distribution and satisfies the desired complex spatial arrangement.First,the irregular geometries of the realistic particles were obtained from the original particle images.Second,the Minkowski sum was used to check the overlap between irregular particles and place an irregular particle in contact with other particles.Third,the optimised advance front method(OAFM)generated irregular particle packing with the prescribed statistical dis-tribution and volume fraction based on the Minkowski sum.Moreover,the signed distance function was introduced to pack the particles in accordance with the desired spatial arrangement.Finally,seven biaxial tests were performed using the UDEC software,which demonstrated the accuracy and potential usefulness of the proposed method.It can model granular material efficiently and reflect the meso-structural characteristics of complex granular materials.This method has a wide range of applications where discrete modelling of granular media is necessary. 展开更多
关键词 Minkowski sum Optimised advance front method(OAFM) Spatial arrangement irregular particle packing Statistical distribution
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On the problem of the dynamical reactions of a rolling wheelset to real track irregularities
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作者 Hans True Lasse Engbo Christiansen +2 位作者 Andreas Lindhardt Plesner Andreas Lønstrup Ammitzbøll Bjørn Jerram Dahl 《Railway Engineering Science》 2023年第1期1-19,共19页
We investigate numerically the dynamical reactions of a moving wheelset model to real measured track irregularities.The background is to examine whether the dynamics are suitable as the input to the inverse problem:de... We investigate numerically the dynamical reactions of a moving wheelset model to real measured track irregularities.The background is to examine whether the dynamics are suitable as the input to the inverse problem:determine the true track geometry from measured wheelset dynamical reactions.It is known that the method works well for the vertical position of the rails but the computed lateral position is often flawed.We find that the lateral motion of the wheelset often may differ from the track geometry.The cases are investigated closely but the reasons remain unknown.While the wheelset dynamics reflect the larger(>4-6 mm)aperiodic track disturbances and single large disturbances quite well,this does not seem to be the case for general smaller or periodic track irregularities or sections behind single large disturbances.The resulting dynamics of a wheelset to lateral track irregularities are in general not sufficiently accurate to be used as the basis for a description of the track irregularities. 展开更多
关键词 Track monitoring Vehicle dynamical response Inverse problem Numerical analysis Estimate of errors Track irregularity
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Influence of Vertical Irregularity on the Seismic Behavior of Base Isolated RC Structures with Lead Rubber Bearings under Pulse-Like Earthquakes
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作者 Ali Mahamied Amjad AYasin +2 位作者 Yazan Alzubi Jamal Al Adwan Issa Mahamied 《Structural Durability & Health Monitoring》 EI 2023年第6期501-519,共19页
Nowadays,an extensive number of studies related to the performance of base isolation systems implemented in regular reinforced concrete structures subjected to various types of earthquakes can be found in the literatu... Nowadays,an extensive number of studies related to the performance of base isolation systems implemented in regular reinforced concrete structures subjected to various types of earthquakes can be found in the literature.On the other hand,investigations regarding the irregular base-isolated reinforced concrete structures’performance when subjected to pulse-like earthquakes are very scarce.The severity of pulse-like earthquakes emerges from their ability to destabilize the base-isolated structure by remarkably increasing the displacement demands.Thus,this study is intended to investigate the effects of pulse-like earthquake characteristics on the behavior of low-rise irregular base-isolated reinforced concrete structures.Within the study scope,investigations related to the impact of the pulse-like earthquake characteristics,irregularity type,and isolator properties will be conducted.To do so,different values of damping ratios of the base isolation system were selected to investigate the efficiency of the lead rubber-bearing isolator.In general,the outcomes of the study have shown the significance of vertical irregularity on the performance of base-isolated structures and the considerable effect of pulse-like ground motions on the buildings’behavior. 展开更多
关键词 Reinforced concrete low-rise structure vertical irregularity the influence of pulse-like earthquake characteristics lead rubber bearing isolators nonlinear response history analysis
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Refined disturbance observer based prescribed performance fixed-time control of high-speed EMS trains with track irregularities
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作者 Yiran Xie Boyang Zhao Xiuming Yao 《High-Speed Railway》 2023年第3期171-178,共8页
High-speed Electromagnetic Suspension(EMS)train is continuously impacted by the irregularity of the track,which worsens the levitation performance of the train.In this paper,a composite control scheme for the EMS is p... High-speed Electromagnetic Suspension(EMS)train is continuously impacted by the irregularity of the track,which worsens the levitation performance of the train.In this paper,a composite control scheme for the EMS is proposed to suppress track irregularities by integrating a Refined Disturbance Observer(RDO)and a Prescribed Performance Fixed-Time Controller(PPFTC).The RDO is designed to estimate precisely the track irregularities and lumped disturbances with uncertainties and exogenous disturbances in the suspension system,and reduce input chattering by applying to the disturbance compensation channel.PPFTC is designed to converge the suspension air gap error to equilibrium point with prescribed performance by completing error conversion,and solve the fast dynamic issue of EMS.And the boundary of overshoot and steady-state is limited in the ranged prescribed.A theoretical analysis is conducted on the stability of the proposed control method.Finally,the effectiveness and reasonability of the proposed composite anti-disturbance control scheme is verified by simulation results. 展开更多
关键词 High-speed electromagnetic suspension train Track irregularity Refined disturbance observer Prescribed performance Fixed-time control
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Use of Irregular Wood Components to Design Non-Standard Structures
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作者 Jean Claude Bignon 《Journal of Civil Engineering and Architecture》 2023年第6期307-313,共7页
This project deals with architecture and engineering involved in the process of architectural design.Based on native irregular components,it aims at developing an innovative approach in the conception and rationalizat... This project deals with architecture and engineering involved in the process of architectural design.Based on native irregular components,it aims at developing an innovative approach in the conception and rationalization of non-standard structures.Contemporary architecture and its non-classical structures require the design of customized pieces.This process which is highly energy and resources consumptive does not always take into account the inherent material properties.This project develops a way of optimizing,in architectural structures,the use of native wood pieces that are not industrially transformed(e.g.boughs)or of reused pieces of carpentry.As a consequence,the ecological footprint of the structures would be reduced. 展开更多
关键词 Architecture timber structure native irregular resources environmental foot-print
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防空作战中多边形责任区预警机空域配置方法
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作者 祁炜 王海杰 +1 位作者 程东升 郑澳粤 《现代防御技术》 北大核心 2024年第1期74-82,共9页
针对防空作战中不规则多边形责任区预警机空域配置问题,基于预警机巡逻航线最短直飞距离和最小转弯直径所形成的实时探测区,通过寻优算法确定预警机责任子区和相应的预警机巡逻可用空域,再基于预警机稳定覆盖度评估准则,对其空域配置进... 针对防空作战中不规则多边形责任区预警机空域配置问题,基于预警机巡逻航线最短直飞距离和最小转弯直径所形成的实时探测区,通过寻优算法确定预警机责任子区和相应的预警机巡逻可用空域,再基于预警机稳定覆盖度评估准则,对其空域配置进一步寻优,得到预警机空域配置优化方案。通过算例仿真验证了此种方法在不规则多边形责任区中规划预警机空域配置的可行性和提升作战效能的有效性,其方法具有较强的实用价值和军事价值。 展开更多
关键词 不规则多边形 预警机 责任子区 可用空域 作战效能
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