针对某铁路局应急通信系统转发视频流至国铁集团应急通信系统时出现视频卡顿的问题,利用数据网业务质量智能感知系统对应急通信视频业务进行监控分析,确定视频卡顿原因,提出采用RTP+实时传输控制协议(Real-Time Control Protocol,RTCP)...针对某铁路局应急通信系统转发视频流至国铁集团应急通信系统时出现视频卡顿的问题,利用数据网业务质量智能感知系统对应急通信视频业务进行监控分析,确定视频卡顿原因,提出采用RTP+实时传输控制协议(Real-Time Control Protocol,RTCP)传输UDP数据包以保证视频流数据传输可靠有序的解决方案。展开更多
A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving ...A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving 50 ft transmission lines and a pair of feedback networks for offset cancellation. At a positive supply voltage of 2 V and a negative supply voltage of - 2V, the power dissipation is about 280 mW. The small-signal gain is higher than 46 dB and the input dynamic range is about 40 dB with a constant single-ended output voltage swing of 400 mV. Satisfactory eye-diagrams are obtained at the bit rate of 12 Gbit/s limited by the test set-up. The chip area is 1.15 mm ×0.7 mm.展开更多
Traffic wave theory is used to study the critical conditions for traffic jams according to their features. First, the characteristics of traffic wave propagation is analyzed for the simple signal-controlled lane and t...Traffic wave theory is used to study the critical conditions for traffic jams according to their features. First, the characteristics of traffic wave propagation is analyzed for the simple signal-controlled lane and the critical conditions for oversaturation is established. Then, the basic road is decomposed into a series of one-way links according to its topological characteristics. Based on the decomposition, traffic wave propagation under complex conditions is studied. Three complicated factors are considered to establish the corresponding critical conditions of jam formation, namely, dynamic and insufficient split, channelized section spillover and endogenous traffic flow. The results show that road geometric features, traffic demand structures and signal settings influence the formation and propagation of traffic congestion. These findings can serve as a theoretical basis for future network jam control.展开更多
The dynamic performance and the stability are essential for a system. A new circuit topology used for electrical discharge machining (EDM) power and made up of complex-pulse (voltage-pulse and current-pulse) is presen...The dynamic performance and the stability are essential for a system. A new circuit topology used for electrical discharge machining (EDM) power and made up of complex-pulse (voltage-pulse and current-pulse) is presented. The large-signal model of it is also derived. Based on the comprehensive analysis of the system model, the compensator is designed to make the system match better and to improve its dynamic performance and the stability under perturbations. Finally, the design methods and the analysis are verified by simulation and experimental results.展开更多
A neuronal signal detecting circuit and a neuronal signal stimulating circuit designed for a monolithic integrated MEA（micro-electrode array） system are described. As a basic cell of the circuits, an OPA（ operation...A neuronal signal detecting circuit and a neuronal signal stimulating circuit designed for a monolithic integrated MEA（micro-electrode array） system are described. As a basic cell of the circuits, an OPA（ operational amplifier） is designed with low power, low noise, small size and high gain. The detecting circuit has a chip area of 290 μm × 400 μm, a power dissipation of 2.02 mW, an equivalent input noise of 17.72 nV/ Hz, a gain of 60. 5 dB, and an output voltage from - 2. 48 to ＋ 2. 5 V. The stimulating circuit has a chip area of 130 μm × 290 μm, a power dissipation of 740 μW, and an output voltage from - 2. 5 to 2. 04 V. The parameters show that two circuits are suitable for a monolithic integrated MEA system. The detecting circuit and MEA have been fabricated. The test results show that the detecting circuit works well.展开更多
A capacity model of multi-phase signalized intersections is derived by a stopping-line method. It is simplified with two normal situations： one situation involves one straight lane and one left-turn lane; the other s...A capacity model of multi-phase signalized intersections is derived by a stopping-line method. It is simplified with two normal situations： one situation involves one straight lane and one left-turn lane; the other situation involves two straight lanes and one left-turn lane. The results show that the capacity is mainly relative to signal cycle length, phase length, intersection layout and following time. With regard to the vehicles arrival rates, the optimal model is derived based on each phase＇s remaining time balance, and it is solved by Lagrange multipliers. Therefore, the calculation models of the optimal signal cycle length and phase lengths are derived and simplified. Compared to the existing models, the proposed model is more convenient and practical. Finally, a practical intersection is chosen and its signal cycles and phase lengths are calculated by the proposed model.展开更多
In this paper,a low complexity ESPRIT algorithm based on power method and Orthogo- nal-triangular (QR) decomposition is presented for direction finding,which does not require a priori knowledge of source number and th...In this paper,a low complexity ESPRIT algorithm based on power method and Orthogo- nal-triangular (QR) decomposition is presented for direction finding,which does not require a priori knowledge of source number and the predetermined threshold (separates the signal and noise ei- gen-values).Firstly,according to the estimation of noise subspace obtained by the power method,a novel source number detection method without eigen-decomposition is proposed based on QR de- composition.Furthermore,the eigenvectors of signal subspace can be determined according to Q matrix and then the directions of signals could be computed by the ESPRIT algorithm.To determine the source number and subspace,the computation complexity of the proposed algorithm is approximated as (2log_2 n+2.67)M^3,where n is the power of covariance matrix and M is the number of array ele- ments.Compared with the Single Vector Decomposition (SVD) based algorithm,it has a substantial computational saving with the approximation performance.The simulation results demonstrate its effectiveness and robustness.展开更多
A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the...A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables, such as polymerization temperature, the ratio of hydrogen to ethylene, the ratio of co-monomer to ethylene, feed rate of catalyst, and bed level. A new performance index, the ratio of melt flow (MFR), is included in the objective function, for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resin. It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product. This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system. The grade transition model is extended to a high space time yield (STY) process with the so-called condensed model operation. In the end, an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the basis of the optimal grade transition model. A sequential transition of six commercial polyethylene grades is illustrated for an optimal multi-product operation.展开更多
Power-line interference is one of the most common noises in magnetotelluric(MT)data.It usually causes distortion at the fundamental frequency and its odd harmonics,and may also affect other frequency bands.Although tr...Power-line interference is one of the most common noises in magnetotelluric(MT)data.It usually causes distortion at the fundamental frequency and its odd harmonics,and may also affect other frequency bands.Although trap circuits are designed to suppress such noise in most of the modern acquisition devices,strong interferences are still found in MT data,and the power-line interference will fluctuate with the changing of load current.The fixed trap circuits often fail to deal with it.This paper proposes an alternative scheme for power-line interference removal based on frequency-domain sparse decomposition.Firstly,the fast Fourier transform of the acquired MT signal is performed.Subsequently,a redundant dictionary is designed to match with the power-line interference which is insensitive to the useful signal.Power-line interference is separated by using the dictionary and a signal reconstruction algorithm of compressive sensing called improved orthogonal matching pursuit(IOMP).Finally,the frequency domain data are switched back to the time domain by the inverse fast Fourier transform.Simulation experiments and real data examples from Lu-Zong ore district illustrate that this scheme can effectively suppress the power-line interference and significantly improve data quality.Compared with time domain sparse decomposition,this scheme takes less time consumption and acquires better results.展开更多
文摘针对某铁路局应急通信系统转发视频流至国铁集团应急通信系统时出现视频卡顿的问题,利用数据网业务质量智能感知系统对应急通信视频业务进行监控分析,确定视频卡顿原因,提出采用RTP+实时传输控制协议(Real-Time Control Protocol,RTCP)传输UDP数据包以保证视频流数据传输可靠有序的解决方案。
文摘A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving 50 ft transmission lines and a pair of feedback networks for offset cancellation. At a positive supply voltage of 2 V and a negative supply voltage of - 2V, the power dissipation is about 280 mW. The small-signal gain is higher than 46 dB and the input dynamic range is about 40 dB with a constant single-ended output voltage swing of 400 mV. Satisfactory eye-diagrams are obtained at the bit rate of 12 Gbit/s limited by the test set-up. The chip area is 1.15 mm ×0.7 mm.
基金The National Basic Research Program of China(973 Program)(No.2006CB705505)the Basic Scientific Research Fund of Jilin University(No.200903209)
文摘Traffic wave theory is used to study the critical conditions for traffic jams according to their features. First, the characteristics of traffic wave propagation is analyzed for the simple signal-controlled lane and the critical conditions for oversaturation is established. Then, the basic road is decomposed into a series of one-way links according to its topological characteristics. Based on the decomposition, traffic wave propagation under complex conditions is studied. Three complicated factors are considered to establish the corresponding critical conditions of jam formation, namely, dynamic and insufficient split, channelized section spillover and endogenous traffic flow. The results show that road geometric features, traffic demand structures and signal settings influence the formation and propagation of traffic congestion. These findings can serve as a theoretical basis for future network jam control.
文摘The dynamic performance and the stability are essential for a system. A new circuit topology used for electrical discharge machining (EDM) power and made up of complex-pulse (voltage-pulse and current-pulse) is presented. The large-signal model of it is also derived. Based on the comprehensive analysis of the system model, the compensator is designed to make the system match better and to improve its dynamic performance and the stability under perturbations. Finally, the design methods and the analysis are verified by simulation and experimental results.
基金The National Natural Science Foundation of China (No.90307013,90707005)the Natural Science Foundation of Jiangsu Province(No. BK2008032)Open Foundation of State Key Laboratory of Bio-Electronics of Southeast University
文摘A neuronal signal detecting circuit and a neuronal signal stimulating circuit designed for a monolithic integrated MEA（micro-electrode array） system are described. As a basic cell of the circuits, an OPA（ operational amplifier） is designed with low power, low noise, small size and high gain. The detecting circuit has a chip area of 290 μm × 400 μm, a power dissipation of 2.02 mW, an equivalent input noise of 17.72 nV/ Hz, a gain of 60. 5 dB, and an output voltage from - 2. 48 to ＋ 2. 5 V. The stimulating circuit has a chip area of 130 μm × 290 μm, a power dissipation of 740 μW, and an output voltage from - 2. 5 to 2. 04 V. The parameters show that two circuits are suitable for a monolithic integrated MEA system. The detecting circuit and MEA have been fabricated. The test results show that the detecting circuit works well.
基金China Postdoctoral Science Foundation(No.2004035208)Jiangsu Communication Science Foundation (No.06Y36)
文摘A capacity model of multi-phase signalized intersections is derived by a stopping-line method. It is simplified with two normal situations： one situation involves one straight lane and one left-turn lane; the other situation involves two straight lanes and one left-turn lane. The results show that the capacity is mainly relative to signal cycle length, phase length, intersection layout and following time. With regard to the vehicles arrival rates, the optimal model is derived based on each phase＇s remaining time balance, and it is solved by Lagrange multipliers. Therefore, the calculation models of the optimal signal cycle length and phase lengths are derived and simplified. Compared to the existing models, the proposed model is more convenient and practical. Finally, a practical intersection is chosen and its signal cycles and phase lengths are calculated by the proposed model.
基金Supported by the National Natural Science Foundation of China (No.60102005).
文摘In this paper,a low complexity ESPRIT algorithm based on power method and Orthogo- nal-triangular (QR) decomposition is presented for direction finding,which does not require a priori knowledge of source number and the predetermined threshold (separates the signal and noise ei- gen-values).Firstly,according to the estimation of noise subspace obtained by the power method,a novel source number detection method without eigen-decomposition is proposed based on QR de- composition.Furthermore,the eigenvectors of signal subspace can be determined according to Q matrix and then the directions of signals could be computed by the ESPRIT algorithm.To determine the source number and subspace,the computation complexity of the proposed algorithm is approximated as (2log_2 n+2.67)M^3,where n is the power of covariance matrix and M is the number of array ele- ments.Compared with the Single Vector Decomposition (SVD) based algorithm,it has a substantial computational saving with the approximation performance.The simulation results demonstrate its effectiveness and robustness.
文摘A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process. The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables, such as polymerization temperature, the ratio of hydrogen to ethylene, the ratio of co-monomer to ethylene, feed rate of catalyst, and bed level. A new performance index, the ratio of melt flow (MFR), is included in the objective function, for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resin. It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product. This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system. The grade transition model is extended to a high space time yield (STY) process with the so-called condensed model operation. In the end, an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the basis of the optimal grade transition model. A sequential transition of six commercial polyethylene grades is illustrated for an optimal multi-product operation.
基金Project(2014AA06A602)supported by the National High-Tech Research and Development Program of ChinaProjects(41404111,41304098)supported by the National Natural Science Foundation of ChinaProject(2015JJ3088)supported by the Natural Science Foundation of Hunan Province,China
文摘Power-line interference is one of the most common noises in magnetotelluric(MT)data.It usually causes distortion at the fundamental frequency and its odd harmonics,and may also affect other frequency bands.Although trap circuits are designed to suppress such noise in most of the modern acquisition devices,strong interferences are still found in MT data,and the power-line interference will fluctuate with the changing of load current.The fixed trap circuits often fail to deal with it.This paper proposes an alternative scheme for power-line interference removal based on frequency-domain sparse decomposition.Firstly,the fast Fourier transform of the acquired MT signal is performed.Subsequently,a redundant dictionary is designed to match with the power-line interference which is insensitive to the useful signal.Power-line interference is separated by using the dictionary and a signal reconstruction algorithm of compressive sensing called improved orthogonal matching pursuit(IOMP).Finally,the frequency domain data are switched back to the time domain by the inverse fast Fourier transform.Simulation experiments and real data examples from Lu-Zong ore district illustrate that this scheme can effectively suppress the power-line interference and significantly improve data quality.Compared with time domain sparse decomposition,this scheme takes less time consumption and acquires better results.
