Based on detail analysis of clutch engaging process control targets and adaptive demands, a control strategy which is based on speed signal, different from that of based on main clutch displacement signal, is put forw...Based on detail analysis of clutch engaging process control targets and adaptive demands, a control strategy which is based on speed signal, different from that of based on main clutch displacement signal, is put forward. It considers both jerk and slipping work which are the most commonly used quality evaluating indexes of vehicle starting phase. The adaptive control system and its reference model are discussed profoundly. Taking the adaptability to different starting gears and different road conditions as examples, some proving field test records are shown to illustrate the main clutch adaptive control strategy at starting phase. Proving field test gives acceptable results.展开更多
The traditional communication system is effectively designed for the worst-case channel state and it can not use the spectral efficiently over the time-varying multipath channel. In order to improve the spectral effic...The traditional communication system is effectively designed for the worst-case channel state and it can not use the spectral efficiently over the time-varying multipath channel. In order to improve the spectral efficiency and ensure robust and spectrally-efficient transmission over the time-varying multipath channel,a joint rate control and adaptive modulation and coding ( AMC) algorithm for adaptive transmission systems is proposed in this paper. Firstly,the proposed algorithm can formulate a modulation and coding scheme ( MCS) switching table according to the offline simulation results and the target bit error rate ( BER) . Then,the optimal MCS is selected in MCS switching table according to the channel state information ( CSI) and then passes to the transmitter and receiver to implement. So the adaptive system which always uses the optimal MCS to transmit signals uses the spectral efficiently. The simulation results validate the proposed algorithm and show that under the premise of meeting the target BER,the adaptive system performing the proposed algorithm has a higher average spectral efficiency ( ASE) than that of the non-adaptive system.展开更多
Due to the rapid development of electronic countermeasures(ECMs),the corresponding means of electronic counter countermeasures(ECCMs)are urgently needed.In this paper,an act-ive anti-jamming method based on frequency ...Due to the rapid development of electronic countermeasures(ECMs),the corresponding means of electronic counter countermeasures(ECCMs)are urgently needed.In this paper,an act-ive anti-jamming method based on frequency diverse array radar is proposed.By deriving the closed form of the phase center in a uniform line array FDA,we establish a model of the FDA signal based on adaptive weights and derive the effect of active anti-jamming in this regime.The pro-posed active anti-jamming method makes it difficult for jammers to detect or locate our radar.Fur-thermore,the effectiveness of the two frequency increment schemes in terms of anti-jamming is ana-lyzed by comparing the deviation of phase center.Finally,the simulation results verify the effective-ness and superiority of the proposed method.展开更多
There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great ...There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks. This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.展开更多
A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristi...A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43 Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.展开更多
In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of E...In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of ELF-EM signal and the signal to noise ratio(SNR)at the receiving end,the DQPSK modulation was proposed as the modulation method for the communication of electromagnetic wave system.Different from the traditional IQ orthogonal modulation and coherent demodulation methods,the proposed phase selection modulation and correlation algorithm demodulation are easier to implement and more practical.With regard to the communication synchronization,a fast algorithm,which based on the normalized cross-relation number,was used for waveform matching,and the maximum point of the correlation coefficient was used as the starting point of communication synchronization.The communication simulation results show that the proposed DQPSK modulation signal based on the adaptive combined filtering algorithm has better terminal error rate and transmission rate than the traditional modulation method.Under the same carrier frequency and code width,the transmission rate of DQPSK modulation is 4 to 5 times and 2 times that of PPM modulation and 2DPSK modulation respectively.The communication modulation and demodulation modes as well as the decoding algorithm with combined adaptive filter proposed in this paper can effectively solve practical engineering problems.展开更多
Power sharing among multiterminal high voltage direct current terminals(MT-HVDC)is mainly developed based on a priority or sequential manners,which uses to prevent the problem of overloading due to a predefined contro...Power sharing among multiterminal high voltage direct current terminals(MT-HVDC)is mainly developed based on a priority or sequential manners,which uses to prevent the problem of overloading due to a predefined controller coefficient.Furthermore,fixed power sharing control also suffers from an inability to identify power availability at a rectification station.There is a need for a controller that ensures an efficient power sharing among the MT-HVDC terminals,prevents the possibility of overloading,and utilizes the available power sharing.A new adaptive wireless control for active power sharing among multiterminal(MT-HVDC)systems,including power availability and power management policy,is proposed in this paper.The proposed control strategy solves these issues and,this proposed controller strategy is a generic method that can be applied for unlimited number of converter stations.The rational of this proposed controller is to increase the system reliability by avoiding the necessity of fast communication links.The test system in this paper consists of four converter stations based on three phase-two AC voltage levels.The proposed control strategy for a multiterminal HVDC system is conducted in the power systems computer aided design/electromagnetic transient design and control(PSCAD/EMTDC)simulation environment.The simulation results significantly show the flexibility and usefulness of the proposed power sharing control provided by the new adaptive wireless method.展开更多
In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS)stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quali...In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS)stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quality variation and increasing available bandwidth usage rate. Under the condition that the whole bandwidth evolution is known, we design an optimal algorithm to select layer. When the knowledge of future bandwidth is not available, we also develop an online algorithm based on the optimal algorithm. Simulation showed that both optimal algorithm and online algorithm can offer smoothed video quality evolution.展开更多
One optical fiber transmission system is designed. The modularization optical fiber transmission adapters were utilized in the system, so the system structure could be flexibly sealable. The sub-array adapter and sign...One optical fiber transmission system is designed. The modularization optical fiber transmission adapters were utilized in the system, so the system structure could be flexibly sealable. The sub-array adapter and signal processor adapter were designed and realized utilizing the new field programmable gate array (FP- GA) which could drive the optical transceiver. The transmission agreement was designed based on the data stream. In order to solve the signal synchronization problem of the optical fiber transmitted phased array radar, a method named synchronous clock was designed. The fiber transmission error code rate of the system was zero with an experimental transmission velocity of 800 Mbit/s. The phased array radar system has detected the airplane target, thus validated the feasibility of the design method.展开更多
On the simple continuously variable transmission (CVT) driveline model, the design of adaptive fuzzy control system for CVT vehicle is presented. The adaptive fuzzy control system consists of a scaling factor self-t...On the simple continuously variable transmission (CVT) driveline model, the design of adaptive fuzzy control system for CVT vehicle is presented. The adaptive fuzzy control system consists of a scaling factor self-tuning fuzzy-PI throttle controller, and a hybrid fuzzy-PID CVT ratio and brake controller. The presented adaptive fuzzy control strategy is vehicle model independent, which depends only on the instantaneous vehicle states, but does not depend on vehicle parameters. So it has good robustness against uncertain vehicle parameters and exogenous load disturbance. Simulation results show that the proposed adaptive fuzzy strategy has good adaptability and practicality value.展开更多
The multi-tone interference suppression in HF serial data transmission systemsis analyzed.Analytic expression for the tap weights and minimum mean square errors of theadaptive equalizer in HF serial systems are obtain...The multi-tone interference suppression in HF serial data transmission systemsis analyzed.Analytic expression for the tap weights and minimum mean square errors of theadaptive equalizer in HF serial systems are obtained.The rate of convergence of equalizer indicatethat the equalizer in HF serial system can not only track the rapid variation of HF channel butalso suppress the multi-tone interferences perfectly.展开更多
Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is propos...Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is proposed to promote adaption accuracy at relay. The instantaneous Bit Error Probability (BEP) is calculated according to the LLR of the received signals firstly, then based on it, the equivalent Signal-to-Noise Ratio (SNR) is employed to operate dynamic power scaling by relay. It is theoretically proved that the full diversity order can be attained by the scheme. Besides, the power sensitivity is also analyzed. Simulation results show that the proposed scheme outperform the conventional LAR and can achieve full diversity order. Moreover, its strong adaptation to SNR fluctuation is validated.展开更多
Spiking neurons usually change their membrane properties, especially ion channel activity, during adaptation or synaptic modification to improve information processing and transmission. Using simple and biophysically ...Spiking neurons usually change their membrane properties, especially ion channel activity, during adaptation or synaptic modification to improve information processing and transmission. Using simple and biophysically realistic models, our analyses reveal that activity-dependent regulation of membrane properties contributes to sensitivity adaptation that improves the neuron ability of detecting sub-threshold signals in the presence of background noises. The improvement is achieved by regulating the conductance of ion channels on the membrane, dependent on the neuron firing activity.展开更多
文摘Based on detail analysis of clutch engaging process control targets and adaptive demands, a control strategy which is based on speed signal, different from that of based on main clutch displacement signal, is put forward. It considers both jerk and slipping work which are the most commonly used quality evaluating indexes of vehicle starting phase. The adaptive control system and its reference model are discussed profoundly. Taking the adaptability to different starting gears and different road conditions as examples, some proving field test records are shown to illustrate the main clutch adaptive control strategy at starting phase. Proving field test gives acceptable results.
基金Sponsored by the National Natural Science Foundation and Civil Aviation Administration of China(Grant No.61101122 and 61071104)the Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory(Grant No.ITD-U12004/K1260010)
文摘The traditional communication system is effectively designed for the worst-case channel state and it can not use the spectral efficiently over the time-varying multipath channel. In order to improve the spectral efficiency and ensure robust and spectrally-efficient transmission over the time-varying multipath channel,a joint rate control and adaptive modulation and coding ( AMC) algorithm for adaptive transmission systems is proposed in this paper. Firstly,the proposed algorithm can formulate a modulation and coding scheme ( MCS) switching table according to the offline simulation results and the target bit error rate ( BER) . Then,the optimal MCS is selected in MCS switching table according to the channel state information ( CSI) and then passes to the transmitter and receiver to implement. So the adaptive system which always uses the optimal MCS to transmit signals uses the spectral efficiently. The simulation results validate the proposed algorithm and show that under the premise of meeting the target BER,the adaptive system performing the proposed algorithm has a higher average spectral efficiency ( ASE) than that of the non-adaptive system.
基金the National Natural Science Foundation of China(No.61971438)the Natural Science Founda-tion of Shaanxi Province(No.2019JM-155).
文摘Due to the rapid development of electronic countermeasures(ECMs),the corresponding means of electronic counter countermeasures(ECCMs)are urgently needed.In this paper,an act-ive anti-jamming method based on frequency diverse array radar is proposed.By deriving the closed form of the phase center in a uniform line array FDA,we establish a model of the FDA signal based on adaptive weights and derive the effect of active anti-jamming in this regime.The pro-posed active anti-jamming method makes it difficult for jammers to detect or locate our radar.Fur-thermore,the effectiveness of the two frequency increment schemes in terms of anti-jamming is ana-lyzed by comparing the deviation of phase center.Finally,the simulation results verify the effective-ness and superiority of the proposed method.
文摘There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks. This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.
基金National Nature Science Foundation of China(60320130174)
文摘A simple two-section polarization mode dispersion(PMD) compensator is proposed for multichannel PMD compensation, which can compensate two or even more channels simultaneously. Because of the statistical characteristics and the frequency-dependence of PMD, for current single mode fiber with moderate PMD, the probability that all channels are severely degraded at the same time is extremely small, which makes it possible to compensate a dense wavelength division multiplexing(DWDM) transmission system with moderate PMD using this compensator. It is shown that the outage probability of a 40×43 Gb/s DWDM transmission system using this compensator is decreased significantly from 3.6×10-3 to 3.6×10-5.
基金supported by National Natural Science Foundation of China(No.61771366)Stable-Support Scientific Project of China Research Institute of Radiowave Propagation(Grant No.A132201068 and No.A132107W08)。
文摘In terms of the electromagnetic wave measurement while drilling,the extremely low frequency electromagnetic(ELF-EM)signal below 20Hz is usually chosen as the downhole data carrier.To improve the transmission rate of ELF-EM signal and the signal to noise ratio(SNR)at the receiving end,the DQPSK modulation was proposed as the modulation method for the communication of electromagnetic wave system.Different from the traditional IQ orthogonal modulation and coherent demodulation methods,the proposed phase selection modulation and correlation algorithm demodulation are easier to implement and more practical.With regard to the communication synchronization,a fast algorithm,which based on the normalized cross-relation number,was used for waveform matching,and the maximum point of the correlation coefficient was used as the starting point of communication synchronization.The communication simulation results show that the proposed DQPSK modulation signal based on the adaptive combined filtering algorithm has better terminal error rate and transmission rate than the traditional modulation method.Under the same carrier frequency and code width,the transmission rate of DQPSK modulation is 4 to 5 times and 2 times that of PPM modulation and 2DPSK modulation respectively.The communication modulation and demodulation modes as well as the decoding algorithm with combined adaptive filter proposed in this paper can effectively solve practical engineering problems.
文摘Power sharing among multiterminal high voltage direct current terminals(MT-HVDC)is mainly developed based on a priority or sequential manners,which uses to prevent the problem of overloading due to a predefined controller coefficient.Furthermore,fixed power sharing control also suffers from an inability to identify power availability at a rectification station.There is a need for a controller that ensures an efficient power sharing among the MT-HVDC terminals,prevents the possibility of overloading,and utilizes the available power sharing.A new adaptive wireless control for active power sharing among multiterminal(MT-HVDC)systems,including power availability and power management policy,is proposed in this paper.The proposed control strategy solves these issues and,this proposed controller strategy is a generic method that can be applied for unlimited number of converter stations.The rational of this proposed controller is to increase the system reliability by avoiding the necessity of fast communication links.The test system in this paper consists of four converter stations based on three phase-two AC voltage levels.The proposed control strategy for a multiterminal HVDC system is conducted in the power systems computer aided design/electromagnetic transient design and control(PSCAD/EMTDC)simulation environment.The simulation results significantly show the flexibility and usefulness of the proposed power sharing control provided by the new adaptive wireless method.
基金Project supported by the National Natural Science Foundation of China (No. 60432030) and the NatIonal Science Fund for Distinguished Young Scholars (No. 60525111), China
文摘In this paper, we propose a novel optimal quality adaptation algorithm for MPEG-4 fine granular scalability (FGS)stream over wired network. Our algorithm can maximize perceptual video quality by minimizing video quality variation and increasing available bandwidth usage rate. Under the condition that the whole bandwidth evolution is known, we design an optimal algorithm to select layer. When the knowledge of future bandwidth is not available, we also develop an online algorithm based on the optimal algorithm. Simulation showed that both optimal algorithm and online algorithm can offer smoothed video quality evolution.
基金the Ministerial Level Advanced Research Foundation(30507060)
文摘One optical fiber transmission system is designed. The modularization optical fiber transmission adapters were utilized in the system, so the system structure could be flexibly sealable. The sub-array adapter and signal processor adapter were designed and realized utilizing the new field programmable gate array (FP- GA) which could drive the optical transceiver. The transmission agreement was designed based on the data stream. In order to solve the signal synchronization problem of the optical fiber transmitted phased array radar, a method named synchronous clock was designed. The fiber transmission error code rate of the system was zero with an experimental transmission velocity of 800 Mbit/s. The phased array radar system has detected the airplane target, thus validated the feasibility of the design method.
文摘On the simple continuously variable transmission (CVT) driveline model, the design of adaptive fuzzy control system for CVT vehicle is presented. The adaptive fuzzy control system consists of a scaling factor self-tuning fuzzy-PI throttle controller, and a hybrid fuzzy-PID CVT ratio and brake controller. The presented adaptive fuzzy control strategy is vehicle model independent, which depends only on the instantaneous vehicle states, but does not depend on vehicle parameters. So it has good robustness against uncertain vehicle parameters and exogenous load disturbance. Simulation results show that the proposed adaptive fuzzy strategy has good adaptability and practicality value.
文摘The multi-tone interference suppression in HF serial data transmission systemsis analyzed.Analytic expression for the tap weights and minimum mean square errors of theadaptive equalizer in HF serial systems are obtained.The rate of convergence of equalizer indicatethat the equalizer in HF serial system can not only track the rapid variation of HF channel butalso suppress the multi-tone interferences perfectly.
基金Supported by the National Natural Science Foundationsof China(No.61071090,No.61171093)the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province(CXZZ11_0388,CXLX11_0404)+2 种基金Jiangsu Province Natural Science Foundation Key Projects(11-KJA510001)National Science and Technology KeyProjects(2011ZX03005-004-003)Jiangsu 973 Projects(BK2011027)
文摘Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is proposed to promote adaption accuracy at relay. The instantaneous Bit Error Probability (BEP) is calculated according to the LLR of the received signals firstly, then based on it, the equivalent Signal-to-Noise Ratio (SNR) is employed to operate dynamic power scaling by relay. It is theoretically proved that the full diversity order can be attained by the scheme. Besides, the power sensitivity is also analyzed. Simulation results show that the proposed scheme outperform the conventional LAR and can achieve full diversity order. Moreover, its strong adaptation to SNR fluctuation is validated.
基金Supported by the National Basic Research Programme of China under Grant No 2005CB724301, the National Natural Science Foundation of China under Grant No 60375039, and the Ministry of Education of China under Grant No 20040248062. The authors thank Mr Huang Shi-Yong for helpful discussion.
文摘Spiking neurons usually change their membrane properties, especially ion channel activity, during adaptation or synaptic modification to improve information processing and transmission. Using simple and biophysically realistic models, our analyses reveal that activity-dependent regulation of membrane properties contributes to sensitivity adaptation that improves the neuron ability of detecting sub-threshold signals in the presence of background noises. The improvement is achieved by regulating the conductance of ion channels on the membrane, dependent on the neuron firing activity.