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A multi-input and multi-output design on automotive engine management system
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作者 翟禹嘉 孙研 +1 位作者 钱科军 LEE Sang-hyuk 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第12期4687-4692,共6页
Lookup table is widely used in automotive industry for the design of engine control units(ECU).Together with a proportional-integral controller,a feed-forward and feedback control scheme is often adopted for automotiv... Lookup table is widely used in automotive industry for the design of engine control units(ECU).Together with a proportional-integral controller,a feed-forward and feedback control scheme is often adopted for automotive engine management system(EMS).Usually,an ECU has a structure of multi-input and single-output(MISO).Therefore,if there are multiple objectives proposed in EMS,there would be corresponding numbers of ECUs that need to be designed.In this situation,huge efforts and time were spent on calibration.In this work,a multi-input and multi-out(MIMO) approach based on model predictive control(MPC) was presented for the automatic cruise system of automotive engine.The results show that the tracking of engine speed command and the regulation of air/fuel ratio(AFR) can be achieved simultaneously under the new scheme.The mean absolute error(MAE) for engine speed control is 0.037,and the MAE for air fuel ratio is 0.069. 展开更多
关键词 neural network spark-ignition engine dynamical system modeling system identification multi-input and mult-output(MIMO) control system
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APPLICATION OF FRF ESTIMATOR BASED ON ERRORS-IN-VARIABLES MODEL IN MULTI-INPUT MULTI-OUTPUT VIBRATION CONTROL SYSTEM
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作者 GUAN Guangfeng CONG Dacheng HAN Junwei LI Hongren 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第4期101-105,共5页
The FRF estimator based on the errors-in-variables (EV) model of multi-input multi-output (MIMO) system is presented to reduce the bias error of FRF HI estimator. The FRF HI estimator is influenced by the noises i... The FRF estimator based on the errors-in-variables (EV) model of multi-input multi-output (MIMO) system is presented to reduce the bias error of FRF HI estimator. The FRF HI estimator is influenced by the noises in the inputs of the system and generates an under-estimation of the true FRF. The FRF estimator based on the EV model takes into account the errors in both the inputs and outputs of the system and would lead to more accurate FRF estimation. The FRF estimator based on the EV model is applied to the waveform replication on the 6-DOF (degree-of-freedom) hydraulic vibration table. The result shows that it is favorable to improve the control precision of the MIMO vibration control system. 展开更多
关键词 multi-input multi-output(MIMO) system Errors-in-variables(EV) model 6-DOF hydraulic vibration table Waveform replication
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Multi-output Gaussian Process Regression Model with Combined Kernel Function for Polyester Esterification Processes
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作者 王恒骞 耿君先 陈磊 《Journal of Donghua University(English Edition)》 CAS 2023年第1期27-33,共7页
In polyester fiber industrial processes,the prediction of key performance indicators is vital for product quality.The esterification process is an indispensable step in the polyester polymerization process.It has the ... In polyester fiber industrial processes,the prediction of key performance indicators is vital for product quality.The esterification process is an indispensable step in the polyester polymerization process.It has the characteristics of strong coupling,nonlinearity and complex mechanism.To solve these problems,we put forward a multi-output Gaussian process regression(MGPR)model based on the combined kernel function for the polyester esterification process.Since the seasonal and trend decomposition using loess(STL)can extract the periodic and trend characteristics of time series,a combined kernel function based on the STL and the kernel function analysis is constructed for the MGPR.The effectiveness of the proposed model is verified by the actual polyester esterification process data collected from fiber production. 展开更多
关键词 seasonal and trend decomposition using loess(STL) multi-output Gaussian process regression combined kernel function polyester esterification process
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An Industrial Intrusion Detection Method Based on Hybrid Convolutional Neural Networks with Improved TCN
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作者 Zhihua Liu Shengquan Liu Jian Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第1期411-433,共23页
Network intrusion detection systems(NIDS)based on deep learning have continued to make significant advances.However,the following challenges remain:on the one hand,simply applying only Temporal Convolutional Networks(... Network intrusion detection systems(NIDS)based on deep learning have continued to make significant advances.However,the following challenges remain:on the one hand,simply applying only Temporal Convolutional Networks(TCNs)can lead to models that ignore the impact of network traffic features at different scales on the detection performance.On the other hand,some intrusion detection methods considermulti-scale information of traffic data,but considering only forward network traffic information can lead to deficiencies in capturing multi-scale temporal features.To address both of these issues,we propose a hybrid Convolutional Neural Network that supports a multi-output strategy(BONUS)for industrial internet intrusion detection.First,we create a multiscale Temporal Convolutional Network by stacking TCN of different scales to capture the multiscale information of network traffic.Meanwhile,we propose a bi-directional structure and dynamically set the weights to fuse the forward and backward contextual information of network traffic at each scale to enhance the model’s performance in capturing the multi-scale temporal features of network traffic.In addition,we introduce a gated network for each of the two branches in the proposed method to assist the model in learning the feature representation of each branch.Extensive experiments reveal the effectiveness of the proposed approach on two publicly available traffic intrusion detection datasets named UNSW-NB15 and NSL-KDD with F1 score of 85.03% and 99.31%,respectively,which also validates the effectiveness of enhancing the model’s ability to capture multi-scale temporal features of traffic data on detection performance. 展开更多
关键词 Intrusion detection industrial internet channel spatial attention multiscale features dynamic fusion multi-output learning strategy
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Walsh Spectral Characteristics and the Auto-Correlation Function Characteristics of Forming Orthomorphic Permutations of Multi-Output Functions 被引量:4
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作者 ZHAO Yaqun WANG Jue 《Wuhan University Journal of Natural Sciences》 CAS 2006年第6期1895-1898,共4页
Orthomorphic permutations have good characteristics in cryptosystems. In this paper, by using of knowledge about relation between orthomorphic permutations and multi-output functions, and conceptions of the generalize... Orthomorphic permutations have good characteristics in cryptosystems. In this paper, by using of knowledge about relation between orthomorphic permutations and multi-output functions, and conceptions of the generalized Walsh spectrum of multi-output functions and the auto-correlation function of multi-output functions to investigate the Walsh spectral characteristics and the auto-correlation function characteristics of orthormophic permutations, several results are obtained. 展开更多
关键词 orthomorphic permutation multi-output functions walsh spectral auto-correlation function
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Relationship between Multi-Output Partially Bent Functions and Multi-Output Bent Functions 被引量:2
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作者 ZHAO Yaqun JU Guizhi WANG Jue 《Wuhan University Journal of Natural Sciences》 CAS 2006年第6期1887-1890,共4页
In this paper, the definition of multl-output partially Bent functions is presented and some properties are discussed. Then the relationship between multi-output partially Bent functions and multi-output Bent function... In this paper, the definition of multl-output partially Bent functions is presented and some properties are discussed. Then the relationship between multi-output partially Bent functions and multi-output Bent functions is given in Theorem 4, which includes Walsh spectrum expression and function expression. This shows that multi-output partially Bent functions and multi-output Bent functions can define each other in principle. So we obtain the general method to construct multi-output partially Bent functions from multi-output Bent functions. 展开更多
关键词 multi-output partially Bent functions multi-output Bent functions Walsh spectrum CONSTRUCTING
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Application of multi-outputs LSSVR by PSO to the aero-engine model 被引量:5
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作者 Lu Feng Huang Jinquan Qiu Xiaojie 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第5期1153-1158,共6页
Considering the modeling errors of on-board self-tuning model in the fault diagnosis of aero-engine, a new mechanism for compensating the model outputs is proposed. A discrete series predictor based on multi-outputs l... Considering the modeling errors of on-board self-tuning model in the fault diagnosis of aero-engine, a new mechanism for compensating the model outputs is proposed. A discrete series predictor based on multi-outputs least square support vector regression (LSSVR) is applied to the compensation of on-board self-tuning model of aero-engine, and particle swarm optimization (PSO) is used to the kernels selection of multi-outputs LSSVR. The method need not reconstruct the model of aero-engine because of the differences in the individuals of the same type engines and engine degradation after use. The concrete steps for the application of the method are given, and the simulation results show the effectiveness of the algorithm. 展开更多
关键词 AERO-ENGINE on-board self-tuning model multi-outputs least square support vector regression particle swarm optimization.
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Cloud removal of remote sensing image based on multi-output support vector regression 被引量:3
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作者 Gensheng Hu Xiaoqi Sun +1 位作者 Dong Liang Yingying Sun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第6期1082-1088,共7页
Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-... Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-scale decomposition of the area of thin cloud cover on remote sensing images. Through enhancing coefficients of high frequency and suppressing coefficients of low frequency, the thin cloud is removed. For thick cloud cover, if the areas of thick cloud cover on multi-source or multi-temporal remote sensing images do not overlap, the multi-output support vector regression learning method is used to remove this kind of thick clouds. If the thick cloud cover areas overlap, by using the multi-output learning of the surrounding areas to predict the surface features of the overlapped thick cloud cover areas, this kind of thick cloud is removed. Experimental results show that the proposed cloud removal method can effectively solve the problems of the cloud overlapping and radiation difference among multi-source images. The cloud removal image is clear and smooth. 展开更多
关键词 remote sensing image cloud removal support vector regression multi-output
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IMPROVEMENT OF THE ALGORITHM PRINCIPLES FOR MINIMIZATION OF MULTI-OUTPUT FUNCTIONS
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作者 陈苏 许道荣 《Journal of Electronics(China)》 1993年第2期116-123,共8页
In this paper,the application of extraction principle for logic function minimiza-tion to multi-output case is studied.A defect in original algorithm in dealing with multi-outputextrema is made up,and on this base,thr... In this paper,the application of extraction principle for logic function minimiza-tion to multi-output case is studied.A defect in original algorithm in dealing with multi-outputextrema is made up,and on this base,three kinds of less-than terms in different conditions aredefined.In addition,three kinds of generalized definition of less-than terms are given,so as to findout more efficiently the covers with minimal number of terms and irredundant function outputs.This work makes the multi-output extraction principle closer to perfection.An algorithm basedon the work is presented. 展开更多
关键词 multi-output function MINIMIZATION Reduction of PLA MINIMAL AND-OR expression
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Spectral Characteristics of the Best Affine Approach of Multi-Output m-Valued Logical Functions
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作者 ZHAO Yaqun YING Dinghai FENG Dengguo 《Wuhan University Journal of Natural Sciences》 CAS 2007年第1期185-188,共4页
This paper discusses the best affine approach (BAA) of multi-output m-valued logical functions. First, it gives the spectra of rate of accordance between multi-output m-valued logical functions and their affine func... This paper discusses the best affine approach (BAA) of multi-output m-valued logical functions. First, it gives the spectra of rate of accordance between multi-output m-valued logical functions and their affine functions, then analyzes the BAA of multi-output m-valued logical functions and finally gives the spectral characteristics of BAA of multi-output m-valued logical functions. 展开更多
关键词 multi-output m-valued logical functions linear spectrum cyclic spectrum BAA(best affine approach)
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A TSE based design for MMSE and QRD of MIMO systems based on ASIP
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作者 冯雪林 SHI Jinglin +3 位作者 CHEN Yang FU Yanlu ZHANG Qineng XIAO Feng 《High Technology Letters》 EI CAS 2023年第2期166-173,共8页
A Taylor series expansion(TSE) based design for minimum mean-square error(MMSE) and QR decomposition(QRD) of multi-input and multi-output(MIMO) systems is proposed based on application specific instruction set process... A Taylor series expansion(TSE) based design for minimum mean-square error(MMSE) and QR decomposition(QRD) of multi-input and multi-output(MIMO) systems is proposed based on application specific instruction set processor(ASIP), which uses TSE algorithm instead of resource-consuming reciprocal and reciprocal square root(RSR) operations.The aim is to give a high performance implementation for MMSE and QRD in one programmable platform simultaneously.Furthermore, instruction set architecture(ISA) and the allocation of data paths in single instruction multiple data-very long instruction word(SIMD-VLIW) architecture are provided, offering more data parallelism and instruction parallelism for different dimension matrices and operation types.Meanwhile, multiple level numerical precision can be achieved with flexible table size and expansion order in TSE ISA.The ASIP has been implemented to a 28 nm CMOS process and frequency reaches 800 MHz.Experimental results show that the proposed design provides perfect numerical precision within the fixed bit-width of the ASIP, higher matrix processing rate better than the requirements of 5G system and more rate-area efficiency comparable with ASIC implementations. 展开更多
关键词 multi-input and multi-output(MIMO) minimum mean-square error(MMSE) QR decomposition(QRD) Taylor series expansion(TSE) application specific instruction set processor(ASIP) instruction set architecture(ISA) single instruction multiple data(SIMD) very long instruction word(VLIW)
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用于5G多波束MIMO系统的先进低温共烧陶瓷封装的39 GHz双信道收发器芯片组 被引量:1
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作者 尹宇明 Zhilin Chen +4 位作者 赵晨曦 刘辉华 吴韵秋 Wen-Yan Yin 康凯 《Engineering》 SCIE EI CAS CSCD 2023年第3期125-140,共16页
本文介绍了一种用于5G多输入多输出(MIMO)应用的39 GHz收发器前端芯片组。每个芯片包括两个可变增益的频率转换通道,可以同时支持两个独立波束,芯片还集成了一个本地振荡器链和数字模块,用于多芯片扩展和增益状态控制。为了提高射频性能... 本文介绍了一种用于5G多输入多输出(MIMO)应用的39 GHz收发器前端芯片组。每个芯片包括两个可变增益的频率转换通道,可以同时支持两个独立波束,芯片还集成了一个本地振荡器链和数字模块,用于多芯片扩展和增益状态控制。为了提高射频性能,对前端系统的关键模块提出了几种电路级改进技术。此外,开发了一种先进的低温共烧陶瓷工艺来封装39 GHz双通道收发器芯片组,实现了低封装损耗和两个发射(TX)/接收(RX)通道之间的高隔离。进行了芯片级和系统级封装(SIP)测量,以演示收发器芯片组的性能。测量结果表明,TX SIP的最大增益为11 dB,饱和输出功率为10 dBm;RX SIP的最大增益为52 dB,噪声系数为5.4 dB,输出压缩点为7.2 dBm。该收发器的单通道通信链路测试表明,64正交调幅(QAM)调制的误差矢量幅度(EVM)为3.72%,频谱效率为3.25 bit·s^(−1)·Hz^(−1);256-QAM调制在1 m距离上的误差矢量幅度(EVM)为3.76%,频谱效率为3.9 bit·s^(−1)·Hz^(−1)。基于该芯片组,还开发了39 GHz多波束原型,用于执行5G毫米波应用的MIMO操作。单流和双流传输的空中通信链路表明,多波束原型机可以覆盖5~150 m的距离,吞吐量相当。 展开更多
关键词 5G MULTI-BEAM multi-input multi-output MILLIMETER-WAVE TRANSCEIVER Wireless communication
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Evaluation of Linear Precoding Schemes for Cooperative Multi-Cell MU MIMO in Future Mobile Communication Systems
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作者 Juma Said Ally 《Journal of Computer and Communications》 2023年第6期28-42,共15页
In Mobile Communication Systems, inter-cell interference becomes one of the challenges that degrade the system’s performance, especially in the region with massive mobile users. The linear precoding schemes were prop... In Mobile Communication Systems, inter-cell interference becomes one of the challenges that degrade the system’s performance, especially in the region with massive mobile users. The linear precoding schemes were proposed to mitigate interferences between the base stations (inter-cell). These schemes are categorized into linear and non-linear;this study focused on linear precoding schemes, which are grounded into three types, namely Zero Forcing (ZF), Block Diagonalization (BD), and Signal Leakage Noise Ratio (SLNR). The study included the Cooperative Multi-cell Multi Input Multi Output (MIMO) System, whereby each Base Station serves more than one mobile station and all Base Stations on the system are assisted by each other by shared the Channel State Information (CSI). Based on the Multi-Cell Multiuser MIMO system, each Base Station on the cell is intended to maximize the data transmission rate by its mobile users by increasing the Signal Interference to Noise Ratio after the interference has been mitigated due to the usefully of linear precoding schemes on the transmitter. Moreover, these schemes used different approaches to mitigate interference. This study mainly concentrates on evaluating the performance of these schemes through the channel distribution models such as Ray-leigh and Rician included in the presence of noise errors. The results show that the SLNR scheme outperforms ZF and BD schemes overall scenario. This implied that when the value of SNR increased the performance of SLNR increased by 21.4% and 45.7% for ZF and BD respectively. 展开更多
关键词 Precoding Schemes Cooperative Networks Interference multi-input multi-output (MIMO) Multi-Cell and Multiuser
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一种复数球形译码算法的仿真 被引量:4
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作者 李颖 王欣 魏急波 《系统仿真学报》 EI CAS CSCD 北大核心 2006年第10期2980-2983,共4页
球形译码算法作为实现最大似然检测的一种有效快速算法受到了学者们的广泛关注。在通信理论中经常使用到复数信号模型,但目前尚未有文献给出在该模型下明晰的算法流程。利用信号星座图的几何特点,推导了一种保持原信号维数的复数球形译... 球形译码算法作为实现最大似然检测的一种有效快速算法受到了学者们的广泛关注。在通信理论中经常使用到复数信号模型,但目前尚未有文献给出在该模型下明晰的算法流程。利用信号星座图的几何特点,推导了一种保持原信号维数的复数球形译码算法;考虑到算法中涉及对整数环的特殊处理,给出了清晰的算法流程。该流程适用于各种复数矩阵信道模型与典型二维信号星座图,为复数模型下球形译码算法的研究提供了一个有效的仿真平台。 展开更多
关键词 复数球形译码 最大似然检测 MIMO(multi-input Multi—output) V-BLAST(Vertical-Bell LABS LAYERED Space-Time)
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Design and Implementation of T-Shaped Planar Antenna for MIMO Applications
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作者 T.Prabhu S.Chenthur Pandian 《Computers, Materials & Continua》 SCIE EI 2021年第11期2549-2562,共14页
This paper proposes,demonstrates,and describes a basic T-shaped Multi-Input and Multi-Output(MIMO)antenna with a resonant frequency of 3.1 to 10.6 GHz.Compared with the U-shaped antenna,the mutual coupling is minimize... This paper proposes,demonstrates,and describes a basic T-shaped Multi-Input and Multi-Output(MIMO)antenna with a resonant frequency of 3.1 to 10.6 GHz.Compared with the U-shaped antenna,the mutual coupling is minimized by using a T-shaped patch antenna.The T-shaped patch antenna shapes filter properties are tested to achieve separation over the 3.1 to 10.6 GHz frequency range.The parametric analysis,including width,duration,and spacing,is designed in the MIMO applications for good isolation.On the FR4 substratum,the configuration of MIMO is simulated.The appropriate dielectric material ε_(r)=4.4 is introduced using this contribution and application array feature of the MIMO systems.In this paper,FR4 is used due to its high dielectric strength and low cost.For 3.1 to 10.6 GHz and 3SRR,T-shaped patch antennas are used in the field to increase bandwidth.The suggested Tshaped MIMO antenna is calculated according to the HFSS 13.0 program simulation performances.The antenna suggested is,therefore,a successful WLAN candidate. 展开更多
关键词 multi-input and multi-output FR4 substratum t-shaped patch antennas ISM band HFSS 13.0 WLAN
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Matrix Power Control Algorithm for Multi-input Multi-output Random Vibration Test 被引量:11
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作者 CUI Xuli CHEN Huaihai HE Xudong JIANG Shuangyan 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2011年第6期741-748,共8页
Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output (MIMO) random vibration test. During the control process with the difference control algorithm (DCA), a lower tri... Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output (MIMO) random vibration test. During the control process with the difference control algorithm (DCA), a lower triangular matrix is derived from Cholesky decomposition of a reference spectrum matrix. The diagonal elements of the lower triangular matrix (DELTM) may become negative. These negative values have no meaning in physical significance and can cause divergence of auto-power spectrum control. A proportional root mean square control algorithm (PRMSCA) provides another method to avoid the divergence caused by negative values of DELTM, but PRMSCA cannot control the cross-power spectrum. A new control algorithm named matrix power control algorithm (MPCA) is proposed in the paper. MPCA can guarantee that DELTM is always positive in the auto-power spectrum control. MPCA can also control the cross-power spectrum. After these three control algorithms are analyzed, three-input three-output random vibration control tests are implemented on a three-axis vibration shaker. The results show the validity of the proposed MPCA. 展开更多
关键词 multi-input multi-output environmental testing vibration control random vibration auto-power spectrum cross-power spectrum
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Control method for multi-input multi-output non-Gaussian random vibration test with cross spectra consideration 被引量:10
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作者 Ronghui ZHENG Huaihai CHEN Xudong HE 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2017年第6期1895-1906,共12页
A control method for Multi-Input Multi-Output(MIMO) non-Gaussian random vibration test with cross spectra consideration is proposed in the paper. The aim of the proposed control method is to replicate the specified ... A control method for Multi-Input Multi-Output(MIMO) non-Gaussian random vibration test with cross spectra consideration is proposed in the paper. The aim of the proposed control method is to replicate the specified references composed of auto spectral densities, cross spectral densities and kurtoses on the test article in the laboratory. It is found that the cross spectral densities will bring intractable coupling problems and induce difficulty for the control of the multioutput kurtoses. Hence, a sequential phase modification method is put forward to solve the coupling problems in multi-input multi-output non-Gaussian random vibration test. To achieve the specified responses, an improved zero memory nonlinear transformation is utilized first to modify the Fourier phases of the signals with sequential phase modification method to obtain one frame reference response signals which satisfy the reference spectra and reference kurtoses. Then, an inverse system method is used in frequency domain to obtain the continuous stationary drive signals. At the same time, the matrix power control algorithm is utilized to control the spectra and kurtoses of the response signals further. At the end of the paper, a simulation example with a cantilever beam and a vibration shaker test are implemented and the results support the proposed method very well. 展开更多
关键词 Cross spectra Kurtosis control multi-input multi-output NON-GAUSSIAN Random vibration test
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Multi-input multi-output random vibration control using Tikhonov filter 被引量:4
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作者 Cui Song Chen Huaihai +1 位作者 He Xudong Zheng Wei 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第6期1649-1663,共15页
Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces w... Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces will be amplified and the response spectral lines may awfully exceed their tolerances. Most of the major biases between the response spectra and the reference spectra are produced by the amplified noises. However, ordinary control algorithms can hardly reduce the level of noises. The influences of the noises on both the auto- and cross-power spectra are analyzed in this paper. As a conventional frequency domain method on the inverse problem, the Tikhonov filter is adopted in the environment test to suppress the exceeding spectral lines. By altering regularization parameters gradually, the auto-power spectra can be improved in a closed control loop. Instead of using the traditional way of selecting regularization parameters, we observe the coherence change to estimate noise eliminations. Incidentally, the requirement of coherence control can be realized. The errors of the phase are then studied and a phase control algorithm is introduced at the end as a supplement of cross-power spectra control. The Tikhonov filter and the proposed phase control algorithm are tested numerically and experimentally. The results show that the noises in the vicinity of lightly damped resonant peaks are more stubborn. The response spectra are able to be greatly improved by the combination of these two methods. 展开更多
关键词 COHERENCE Environmental testing multi-input multi-output(MIMO) Noise Phase control Tikhonov filter
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Strategies for multi-step-ahead available parking spaces forecasting based on wavelet transform 被引量:4
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作者 季彦婕 高良鹏 +1 位作者 陈晓实 郭卫红 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第6期1503-1512,共10页
A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of avail... A new methodology for multi-step-ahead forecasting was proposed herein which combined the wavelet transform(WT), artificial neural network(ANN) and forecasting strategies based on the changing characteristics of available parking spaces(APS). First, several APS time series were decomposed and reconstituted by the wavelet transform. Then, using an artificial neural network, the following five strategies for multi-step-ahead time series forecasting were used to forecast the reconstructed time series: recursive strategy, direct strategy, multi-input multi-output(MIMO) strategy, DIRMO strategy(a combination of the direct and MIMO strategies), and newly proposed recursive multi-input multi-output(RECMO) strategy which is a combination of the recursive and MIMO strategies. Finally, integrating the predicted results with the reconstructed time series produced the final forecasted available parking spaces. Three findings appear to be consistently supported by the experimental results. First, applying the wavelet transform to multi-step ahead available parking spaces forecasting can effectively improve the forecasting accuracy. Second, the forecasting resulted from the DIRMO and RECMO strategies is more accurate than that of the other strategies. Finally, the RECMO strategy requires less model training time than the DIRMO strategy and consumes the least amount of training time among five forecasting strategies. 展开更多
关键词 available PARKING SPACES MULTI-STEP AHEAD time series forecasting wavelet transform forecasting STRATEGIES recursive multi-input multi-output strategy
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MIMO Channel Measurement and Characterization at 6.0-6.4 GHz Under Typical Classroom Environment 被引量:3
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作者 Ji-Liang Zhang Yang Wang +2 位作者 Li-Qin Ding Xiao-Min Huang Nai-Tong Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第1期69-76,共8页
An extensive 4 × 4 MIMO channel measurement is carried out at 6. 0- 6. 4 GHz under a typical classroom environment with channel sounder based on vector network analyzer. Both LOS and NLOS scenarios are considered... An extensive 4 × 4 MIMO channel measurement is carried out at 6. 0- 6. 4 GHz under a typical classroom environment with channel sounder based on vector network analyzer. Both LOS and NLOS scenarios are considered. The results on path loss,delay spread and spatial correlation are presented. The measurement shows that,for corridor coverage,2×2 MIMO is more economical than 4×4 MIMO due to high correlation. In order to identify the unique characteristics at the high frequency band,the measured channel parameters at 6. 0-6. 4 GHz are compared with those at 2. 45 GHz. The comparison shows that the shortened wavelength of this higher frequency band results in a great difference of channel characteristics. Therefore,our measurement results provide new guidance for the design and development of the system working on 6. 0-6. 4 GHz band. 展开更多
关键词 6.0-6.4 GHz multi-input multi-output(MIMO) channel measurement channel characteristics
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