共查询到20条相似文献，搜索用时 31 毫秒
1.
针对单一预测模型精度不高以及预测结果不能体现经济变量关系的不足,将灰色GM(1,1)模型与多元线性计量经济模型加以耦合,建立了灰色多元线性计量经济模型,并利用该模型对湖南省农村居民人均纯收入进行了预测。灰色多元线性计量经济模型的预测精度不仅明显高于单一的灰色GM(1,1)模型和多元线性回归模型,而且预测结果也能体现经济变量之间的关系。预测结果表明,未来几年湖南省农村居民人均纯收入逐年增长,但增长的速度较为缓慢。最后,给出了几点调控湖南省农村居民收入差距的建议。 相似文献
2.
Motion estimation is the most complex part in H.264. Intra prediction is an important part of motion estimation. There are a number of intra prediction modes in H.264, which no doubt greatly increase encoding complexity. In intra prediction, the way of choosing prediction method is rate distortion optimization or using correlation properties. For complexity problem, the paper provides an improved intra prediction mode selection algorithm. This algorithm uses a new detection method to detect the pixel correlation in the direction of mode selection. Test results show that the algorithm has reduced the computational complexity and increased the encoding speed highly in the premise of ensuring video quality. 相似文献
3.
WANG Ru-yan 《保鲜与加工》2005,(11):24
The author analyzs computational complexity of previous MPEG-4 video codec system in terms of data processing, memory accessing and address computation, and optimizs the performance of data processing and data transfer of MPEG-4 video coding and decoding algorithm. The architecture model of the real-time MPEG-4 video codec is proposed based on the analyses. This architecture can effectively utilize computational resource in software and improve the performance of MPEG-4 video codec system. 相似文献
4.
The study for dealing with the load model in composite system reliability evaluation is almost at a standstill because of the inherent computational complexity. In this paper, an algorithm for composite system reliability evaluation considering load model is proposed. This method is powerful in computation because it can avoid unnecessary state enumeration by means of the relationship among basic reliability informations of load levels. As an example, the IEEE 24-node Reliability Test System is tested on VAX-11/750 computer. The average CPU time to calculate the reliability indices of the system corresponding to a load level is about 5 seconds. 相似文献
5.
In order to consider the feasibility of practical implementation and reduce the complexity of OFDM systems, an improved SLM algorithm is proposed. The original data are segmented and scrambled, which breaks the correlation of the original data sequences, and reduces all sub-carrier phase coherence, thereby reducing the OFDM system PAPR. Following the linear nature of the Fourier transform, the obtained IFFT data sequences are linearly combined to get the new scrambling code sequences, such that strictly controlling the IFFT number, while getting more data sequences, which further reduces the system PAPR, and significantly reduces the computational complexity of the system. Theoretical analysis and simulation results show that the improved SLM algorithm can effectively suppress PAPR, while reducing the algorithm complexity and system complexity. 相似文献
6.
The intense coupled and nonlinear behaviors were observed on the tall long span tower line systems which were under the icing and wind loads in heavy icing areas. A set of stiffness equations of insulator, conductor and boundary conditions was deduced. Taking the ±800 kV UHV DC transmission line from Xiangjiaba to Shanghai as an example, the simplified numerical model of transmission tower, conductor, insulator and constraint was developed. The long span transmission tower line system models under seven loads conditions were analyzed by static nonlinear methods. It was found that the P Δ effect of tower components was small when the covered ice was uniformly distributed. The unbalanced wire loads on the tower would lead to twist effect when the covered ice was uneven distributed. The axial forces, moments at restraint nodes and the longest cantilever member were greatly affected by the P Δ effect, under which the unfavorable effect on the structure should be considered. 相似文献
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In order to improve the rate control performance of video encoder, video frames are segmented into two regions according to the video content, i.e. the foreground region containing the main moving objects and the background region containing the relatively static scene. The rate-distortion properties of the two regions are analyzed. Based on the analyses, a novel region-based macroblock layer rate control method for H.264/AVC is proposed. For the bit allocation process, more target bits can be assigned to the important macroblocks by employing an adaptive factor determined by the region information. Then, the quantization parameter (QP) is computed by using the quadratic model with different parameters related to the two regions. The computed QP is further adjusted to suppress the coding quality fluctuation between the two regions, as well as the quality fluctuation among the consecutive macroblocks. Finally, the rate control parameters are updated after coding the current macroblock. Experimental results demonstrate the mismatches between the actual coding bit-rates and the target bit-rates are reduced, while the coding performance of the encoder and the subjective visual quality of the reconstructed video are improved. 相似文献
9.
渗透系数是控制地下水流动的重要参数,对渗透系数的空间分布规律进行研究具有重要的意义。基于Gardner模型获取了一维稳态流非饱和土渗透系数沿垂直分布模型,该模型用指数函数描述,受饱和渗透系数和无量纲的深度与流动率等因素的控制;该模型表明一维稳态流条件下均质典型土类的渗透系数其沿垂直方向变化趋势主要受比流量与饱和渗流系数的负数值二者之间的相对大小影响。分别采用泰勒级数方法和以地下水位处及地表处的渗透系数作为控制条件方法对一维稳态流非饱和土渗透系数沿垂直分布模型进行线性近似简化。采用泰勒级数方法获取的简化模型其计算误差随无量纲的深度增大而增大。简化后的模型具有形式简单、参数少等特点。通过算例对比简化模型与原模型的差异,计算结果表明:采用以地下水位处及地表处的渗透系数作为控制条件的方法进行线性近似简化的模型计算误差比采用泰勒级数方法获得的线性近似简化模型的计算误差小。 相似文献
10.
It is very difficult to build the accurate mathematical model of the wind turbine generator system because of the uncertainty of air kinetics and the complexity of power electronics, especially when the wind speed changes abruptly or there is a disturbance. But the classical control needs the model. Using neural network controller to the wind turbine generator system can overcome these difficulties. The wind speed can be followed and the maximum power can be obtained under low wind speed by using the power coefficient curve BP neural network and the optimum pitch angle BP neural network. The maximum power can be kept and under the allowed range in the condition of high wind speed. The simulation model and result are given under the environment of MATLAB. The fluctuation of wind speed can be controlled and the disturbance can be cancelled by BP neural network controller. 相似文献
11.
For high precise frequency estimation of the short sinusoid signal at low signal-to-noise ratio (SNR), a weighted fusion algorithm for frequency estimation of the short signal with the same frequency and length (SFL-Signal) is proposed. The spectrum model of SFL-Signal and the phase compensation matrix with phase coherent and noise cancellation are constructed. Secondly, the SFL-signal spectrum is weight-fused with the phase compensation matrix to obtain the result almost the same as that of the spectrum of the phase-coherent sinusoid signal. Consequently, high frequency estimation precision is obtained with spectral peak searching of the weight-fusion spectrum. Algorithm analysis and simulation results show that, compared with the existing methods,the proposed algorithm works better in term of precision, calculation complexity, noise immunity, and fits for any type of SFL-Signal. 相似文献
12.
CHEN Deng-fu~ SUN Hai-feng~ FENG Ke~ BAI Chen-guang~ DONG Ling-yan~ WEN Liang-ying~ ZHAO Zhan-feng~ 《保鲜与加工》2004,(7):56-59
A dynamic control arithmetic and mathematic model of secondary cooling system for ROKOP billet concasting has been developed in view of the changes of casting speed during concasting process and the high fluctuation of surface temperature due to the use of static control method. By means of computer simulation and by comparison between static and dynamic control method, it proves that the latter one is more adaptive to the changes of casting speed, which leads to lower fluctuation of surface temperature. 相似文献
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By combining a driver model, a vehicle system dynamics model, and a vehicle lateral stability control system, the performance of the driver vehicle road closed loop system through a pylon course slalom test was simulated. The simulation was done in accordance with the GB/T6323.1-94 standard. Vehicle stability control system effectiveness was evaluated by measuring the mean maximum yaw rate and the mean maximum steering wheel angle. The simulation results showed the slalom test value with lateral stability control was approximately 4% higher than without a stability control system. This indicates the controlling system improves vehicle handling stability. 相似文献
14.
A drift error nonlinear compensation algorithm for Fiber Optic Gyro (FOG) is presented based on T-S fuzzy model with the antecedent parameters identified by G-K clustering algorithm and the error model of T-S fuzzy model with the consequent parameters identified by least square algorithm. The computed results show that this model can compensate the original data effectively, while the error principles of FOG do not need to be understood well. Comparing with the original data, compensation with linear fitting and compensation with neural network, the absolute error of the proposed model reduces by 99%, 96% and 10%, respectively. The error variance reduces by 99%, 98% and 20%, respectively. The results indicate that this proposed algorithm can be simply operated with high precision and easy to realize in engineering. 相似文献
15.
中国生猪价格波动的经济学解释 总被引：1，自引：1，他引：0
生猪养殖业在中国具有举足轻重的地位。近年来生猪市场价格波动频繁,对国民经济平稳运行和产业良性发展具有一定影响。对相关文献进行梳理可知,生猪价格波动具有内生性因素和外生性因素,进而文章提出以经济学理论研究生猪价格波动的成因。蛛网模型是解释农产品价格波动的主要工具。以2000年1月至2012年7月的数据为分析对象,发现中国生猪价格波动呈现出整体发散,但局部封闭、收敛的“蛛网紊乱”状态,认为这与中国宏观经济环境的变化,尤其是以利率为代表的货币政策的变化有密切关联。通过仔猪和饲料价格变化分析养殖户的行为,以及根据宏观劳动需求与产量供给分析真实工资与生猪养殖行业之间的关系,是2种探索性的解释,有助于弥补蛛网模型的不足。 相似文献
16.
Cai KunbaoYang RuifangLu XiaoYu JihuiWang Gongrui 《保鲜与加工》1996,(5):42-47
The duality principle in electrical network was generalized to establish the one to one correspondence between generalized linear viscoelastic model and RC electrical network.On this basis,a guess was proved to be true that any generalized linear viscoelastic model with arbitrary complexity can be simplified as generalized Voigt chain equivalently. 相似文献
17.
In system controlled,Sampling these parameters and with parameters for controller in time, it is an object to adaptive control. The article presents a scheme that the structure parameters on it's model and model parameters is robust identified by on line, while to optimal of algorithm on adaptive control is fulfilled. In control scheme, method of intelligent identifying to the structure parameters(levels of model) and algorithm of robust pole placement are introduced also It is advancer for already mentioned scheme. Whole scheme presents new model on adaptive control. 相似文献
18.
In view of the vehicle cornering or path changing under ultimate handling maneuver, a 3-DOF nonlinear vehicle dynamics model which takes the vehicle lateral velocity, yaw rate and body roll angle as the State variables is presented. Based on the dynamic analysis, the method which using additional yaw moment produced by different longitudinal braking force among each wheels to improving vehicle handling stability in emergency situations is discussed. Considering the sideslip angle as one of the vehicle state variables is difficult to measuring, the sideslip angle estimation based on vehicle dynamic model and kinematics is designed. And then, based on the theory of siding model control, the combining sliding model control system is founded, which taking the vehicle yaw rate and body side-slip angle errors between the estimated and the real as the input variables, and taking the braking torque and the steering angle as control aims. The simulation results indicate that the control method can effectively improve the vehicle lateral handling stability. 相似文献
19.
The filtered back-projection algorithm of magnetic induction tomography with uniform magnetic excitation 
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下载免费PDF全文 Helmholtz coils produce uniform sinusoidal magnetic field in the center region, and the direction of magnetic field is approximate straight line, to help simplify the complexity of inverse problems. The simulation models of an 8-channel magnetic induction tomography measurement system are built, reconstructing conductivity distribution with filtered back projection algorithm. In the filtered back projection algorithm, the detected data is supplemented by the linear interpolation first, and then filtered by the Hamming filter, while adding a window filter to reduce the impact of around the coil from the divergence of the magnetic field. The different noise ratio of noise is added in the detected data to test noise suppression ability of the algorithm. The experiment results show that this filtered back projection algorithm can reconstruct the conductivity distribution under this model. 相似文献
20.
This paper presents a new rnethod for analysis and computation of steady-statereal power security region by linear programming.In this method based on the D.C load flow,theupper and lower bounds of the hyper-cuboid explicit steady-state security region are chosen asunknown variables.The objective function is the total amount of the adjustable generations withweighting factors.The model of the steady-state real power security region is changed in to the proposed linearprogramming methed for ealculation.The numerieal exarnples are tested on IEEE 6-bus and 30-bussample systems.The computational resuIts showed the proposed model a nd algorithm feasible andeffective. 相似文献