This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear syst...This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear systems are expanded in the space spanned by DPOFs,and two recurrence formulas for the expansion coefficients of the system’s state variables are obtained.Then,a modified Arnoldi process is applied to both recurrence formulas to construct the orthogonal projection matrices,by which the reduced-order systems are obtained.Theoretical analysis shows that the output variables of the reducedorder systems can match a certain number of the expansion coefficients of the original system’s output variables.Finally,two numerical examples illustrate the feasibility and effectiveness of the proposed methods.展开更多
In this paper we study the degenerate differential system with delay:E(t)=Ax(t)+Bx(t-1)+f(t),give the canonical form of this systems and study this form of degeneration system with delay,have some results for the so...In this paper we study the degenerate differential system with delay:E(t)=Ax(t)+Bx(t-1)+f(t),give the canonical form of this systems and study this form of degeneration system with delay,have some results for the solvability of such systems and the uniqueness of their solutions.展开更多
For orthogonal frequency division multiplexing (OFDM) wireless communication, the system throughput and data rate are usually limited by pilots, especially in a high mobility environment. In this paper, an enhanced it...For orthogonal frequency division multiplexing (OFDM) wireless communication, the system throughput and data rate are usually limited by pilots, especially in a high mobility environment. In this paper, an enhanced iterative joint channel estimation and symbol detection algorithm is proposed to enhance the system throughput and data rate. With lower pilot power, the proposed scheme increases system throughput firstly, and then the channel estimation and symbol detection proceed iteratively within one OFDM symbol to improve the BER performance. In the proposed algorithm, the original channel estimate of each OFDM symbol is based on the channel estimate of the previous OFDM symbol, thus the variation of the mobile channel is traced efficiently, so the number of pilots in the time domain can be reduced greatly. Besides reducing the system overhead, the proposed algorithm is also shown by simulation to give much better BER performance than the conventional iterative algorithm does.展开更多
A new system-corrected CMOS audio power AMP is presented. Consisting of four single-end OPAs,this structure is a pseudo-differential system. Compared to conventional CMOS power AMPs, it has the merits of low power con...A new system-corrected CMOS audio power AMP is presented. Consisting of four single-end OPAs,this structure is a pseudo-differential system. Compared to conventional CMOS power AMPs, it has the merits of low power consumption, extremely low THD,easy compensation, and good driving capability. With 1st silicon 0.25μm 1P4M CMOS technology and a 3V power supply,the output range can be 4Vpp when driving an 8Ω‖ 300pF load, while its power dissipation is less than 3mW. The THD is better than 0. 003% at 1kHz. A new over-current protection circuit, which can effectively protect the power output circuits on the chip, is also demonstrated.展开更多
The performance of an OFDM/OQAM system under phase noise is analyzed. The analysis helps to direct the design of low cost tuners through specifying the required phase noise characteristics. Discrete time formulation o...The performance of an OFDM/OQAM system under phase noise is analyzed. The analysis helps to direct the design of low cost tuners through specifying the required phase noise characteristics. Discrete time formulation of OFDM/OQAM is first derived with the square root raised cosine (SRRC) filter as the pulse-shaping filter. Then the effect of multiplicative phase noise is equivalently represented as additive white Gaussian noise (AWGN), the variance of which is given analytically. We can observe that the same result as OFDM/QAM system is derived. Lastly, all the analytical results are verified by the bit error rate (BER) degradation through Monte Carlo simulation.展开更多
A new algorithm for constructing an inverse of a multivariable linear system is presented. This algorithm makes the constructing an inverse of the higher order matrices into searching for the equivalent normal form o...A new algorithm for constructing an inverse of a multivariable linear system is presented. This algorithm makes the constructing an inverse of the higher order matrices into searching for the equivalent normal form of the lower order matrices. Consequently, the calculation is more simple efficient and programmed than previous methods. Another result of the paper is that the lower reduced inverse system is obtained, by selecting special bases of the observable space of the original systems, it reveals the effect of the observability of the original systems on the order of the inverse systems.展开更多
Based on the orthodox theory,a model of a single electron transistor （SET） of metallic tunneling junctions is built using the master equation method. Several parameters of the device, such as capacitance, resistance...Based on the orthodox theory,a model of a single electron transistor （SET） of metallic tunneling junctions is built using the master equation method. Several parameters of the device, such as capacitance, resistance and temperature,are input into the model and thus the I-V curves are attained. These curves are consistent with those from other experiments; therefore, the model is verified. However, there still exists a difference between simulated results and experimental results,mainly comes from the stationary case of the master equation. In other words, precision of simulated results would be increased if the transient case of the master equation is considered. Moreover, the current increases exponentially at higher drain voltages, which is due to the fact that the barrier suppression is caused by the image charge potential.展开更多
Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the opti...Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the optimal number of receiving traces in field geometry using a numerical simulation based on a field test conducted in previous research （Zhu et al., 2011）. A mathematical model is established for total energy and average efficiency energy using fixed trace spacing and optimal receiving traces are estimated. Seismic data acquired in a complex work area are used to verify the correctness of the proposed method. Results of model data calculations and actual data processing show that results are in agreement. This indicates that the proposed method is reasonable, correct, sufficiently scientific, and can be regarded as a novel method for use in seismic geometry design in complex geological regions.展开更多
By summing geophone and hydrophone data with opposite polarity responses to water layer reverberation,the ocean bottom cable dual-sensor acquisition technique can effectively eliminate reverberation,broaden the freque...By summing geophone and hydrophone data with opposite polarity responses to water layer reverberation,the ocean bottom cable dual-sensor acquisition technique can effectively eliminate reverberation,broaden the frequency bandwidth,and improve both the resolution and fidelity of the seismic data.It is thus widely used in industry.However,it is difficult to ensure good coupling of the geophones with the seabed because of the impact of ocean flow,seafloor topography,and field operations;therefore,geophone data are seriously affected by the transfer function of the geophone-seabed coupling system.As a result,geophone data frequently have low signal-to-noise ratios（S/N）,which causes large differences in amplitude,frequency,and phases between geophone and hydrophone data that severely affect dual-sensor summation.In contrast,the hydrophone detects changes in brine pressure and has no coupling issues with the seabed;thus,hydrophone data always have good S/N.First,in this paper,the mathematical expression of the transfer function between geophone and seabed is presented.Second,the transfer function of the geophone-seabed is estimated using hydrophone data as reference traces,and finally,the coupling correction based on the estimated transfer function is implemented.Using this processing,the amplitude and phase differences between geophone and hydrophone data are removed,and the S/N of the geophone data are improved.Synthetic and real data examples then show that our method is feasible and practical.展开更多
Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can...Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can cause a series of misstatements and false positives on the monitoring system, which will severely hamper the safe production of coal industry. In this paper, first, the frequency characteristics of the interference source on the power line are extracted when equipment runs normally. Then the finite difference time domain method is introduced to analyze the effects of the electromagnetic interference parameters on the security monitoring signal line. And the interference voltage of the two terminal sides on the single line is taken as evaluating indexes. Finally, the electromagnetic interference parameters are optimized by orthogonal experimental design based on the MATLAB simulation on the normal operation of equipment.展开更多
基金supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region of China“Research on model order reduction methods based on the discrete orthogonal polynomials”(2023D01C163)The Tianchi Talent Introduction Plan Project of Xinjiang Uygur Autonomous Region of China“Research on orthogonal decomposition model order reduction methods for discrete control systems”.
文摘This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear systems are expanded in the space spanned by DPOFs,and two recurrence formulas for the expansion coefficients of the system’s state variables are obtained.Then,a modified Arnoldi process is applied to both recurrence formulas to construct the orthogonal projection matrices,by which the reduced-order systems are obtained.Theoretical analysis shows that the output variables of the reducedorder systems can match a certain number of the expansion coefficients of the original system’s output variables.Finally,two numerical examples illustrate the feasibility and effectiveness of the proposed methods.
文摘In this paper we study the degenerate differential system with delay:E(t)=Ax(t)+Bx(t-1)+f(t),give the canonical form of this systems and study this form of degeneration system with delay,have some results for the solvability of such systems and the uniqueness of their solutions.
文摘For orthogonal frequency division multiplexing (OFDM) wireless communication, the system throughput and data rate are usually limited by pilots, especially in a high mobility environment. In this paper, an enhanced iterative joint channel estimation and symbol detection algorithm is proposed to enhance the system throughput and data rate. With lower pilot power, the proposed scheme increases system throughput firstly, and then the channel estimation and symbol detection proceed iteratively within one OFDM symbol to improve the BER performance. In the proposed algorithm, the original channel estimate of each OFDM symbol is based on the channel estimate of the previous OFDM symbol, thus the variation of the mobile channel is traced efficiently, so the number of pilots in the time domain can be reduced greatly. Besides reducing the system overhead, the proposed algorithm is also shown by simulation to give much better BER performance than the conventional iterative algorithm does.
文摘A new system-corrected CMOS audio power AMP is presented. Consisting of four single-end OPAs,this structure is a pseudo-differential system. Compared to conventional CMOS power AMPs, it has the merits of low power consumption, extremely low THD,easy compensation, and good driving capability. With 1st silicon 0.25μm 1P4M CMOS technology and a 3V power supply,the output range can be 4Vpp when driving an 8Ω‖ 300pF load, while its power dissipation is less than 3mW. The THD is better than 0. 003% at 1kHz. A new over-current protection circuit, which can effectively protect the power output circuits on the chip, is also demonstrated.
文摘The performance of an OFDM/OQAM system under phase noise is analyzed. The analysis helps to direct the design of low cost tuners through specifying the required phase noise characteristics. Discrete time formulation of OFDM/OQAM is first derived with the square root raised cosine (SRRC) filter as the pulse-shaping filter. Then the effect of multiplicative phase noise is equivalently represented as additive white Gaussian noise (AWGN), the variance of which is given analytically. We can observe that the same result as OFDM/QAM system is derived. Lastly, all the analytical results are verified by the bit error rate (BER) degradation through Monte Carlo simulation.
文摘A new algorithm for constructing an inverse of a multivariable linear system is presented. This algorithm makes the constructing an inverse of the higher order matrices into searching for the equivalent normal form of the lower order matrices. Consequently, the calculation is more simple efficient and programmed than previous methods. Another result of the paper is that the lower reduced inverse system is obtained, by selecting special bases of the observable space of the original systems, it reveals the effect of the observability of the original systems on the order of the inverse systems.
文摘Based on the orthodox theory,a model of a single electron transistor （SET） of metallic tunneling junctions is built using the master equation method. Several parameters of the device, such as capacitance, resistance and temperature,are input into the model and thus the I-V curves are attained. These curves are consistent with those from other experiments; therefore, the model is verified. However, there still exists a difference between simulated results and experimental results,mainly comes from the stationary case of the master equation. In other words, precision of simulated results would be increased if the transient case of the master equation is considered. Moreover, the current increases exponentially at higher drain voltages, which is due to the fact that the barrier suppression is caused by the image charge potential.
基金supported by the National Natural Science Foundation of China(No.41304115)National Key S&T Special Projects(No.2016ZX050 24001-003)+2 种基金Open Fund for Sichuan Province Key Laboratory of Natural Gas Geology(No.2015trqdz02)the Research Project,CNPC(No.2016A-33)"Young and Middle-aged Key Teachers"Training Program in Southwest Petroleum University
文摘Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the optimal number of receiving traces in field geometry using a numerical simulation based on a field test conducted in previous research （Zhu et al., 2011）. A mathematical model is established for total energy and average efficiency energy using fixed trace spacing and optimal receiving traces are estimated. Seismic data acquired in a complex work area are used to verify the correctness of the proposed method. Results of model data calculations and actual data processing show that results are in agreement. This indicates that the proposed method is reasonable, correct, sufficiently scientific, and can be regarded as a novel method for use in seismic geometry design in complex geological regions.
文摘By summing geophone and hydrophone data with opposite polarity responses to water layer reverberation,the ocean bottom cable dual-sensor acquisition technique can effectively eliminate reverberation,broaden the frequency bandwidth,and improve both the resolution and fidelity of the seismic data.It is thus widely used in industry.However,it is difficult to ensure good coupling of the geophones with the seabed because of the impact of ocean flow,seafloor topography,and field operations;therefore,geophone data are seriously affected by the transfer function of the geophone-seabed coupling system.As a result,geophone data frequently have low signal-to-noise ratios（S/N）,which causes large differences in amplitude,frequency,and phases between geophone and hydrophone data that severely affect dual-sensor summation.In contrast,the hydrophone detects changes in brine pressure and has no coupling issues with the seabed;thus,hydrophone data always have good S/N.First,in this paper,the mathematical expression of the transfer function between geophone and seabed is presented.Second,the transfer function of the geophone-seabed is estimated using hydrophone data as reference traces,and finally,the coupling correction based on the estimated transfer function is implemented.Using this processing,the amplitude and phase differences between geophone and hydrophone data are removed,and the S/N of the geophone data are improved.Synthetic and real data examples then show that our method is feasible and practical.
文摘Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can cause a series of misstatements and false positives on the monitoring system, which will severely hamper the safe production of coal industry. In this paper, first, the frequency characteristics of the interference source on the power line are extracted when equipment runs normally. Then the finite difference time domain method is introduced to analyze the effects of the electromagnetic interference parameters on the security monitoring signal line. And the interference voltage of the two terminal sides on the single line is taken as evaluating indexes. Finally, the electromagnetic interference parameters are optimized by orthogonal experimental design based on the MATLAB simulation on the normal operation of equipment.
