For the high altitude cruising flight phase of a hypersonic cruise missile （HCM）, a relative motion mod- el between the missile and the target is established by defining virtual target and combining the theory of th...For the high altitude cruising flight phase of a hypersonic cruise missile （HCM）, a relative motion mod- el between the missile and the target is established by defining virtual target and combining the theory of the dif- ferential geometry with missile motion equations. Based on the model, the motion between the missile and the tar- get is considered as a single target differential game problem, and a new open-loop differential game midcourse guidance law （DGMGL） is deduced by solving the corresponding Hamiltonian Function. Meanwhile, a new struc- ture of a closed-loop DGMGL is presented and the training data for back propagation neural network （BPNN） are designed. By combining the theory of BPNN with the open-loop DGMGL obtained above, the law intelligence is realized. Finally, simulation is carried out and the validity of the law is testified.展开更多
By combining fractal theory with D-S evidence theory, an algorithm based on the fusion of multi-fractal features is presented. Fractal features are extracted, and basic probability assignment function is designed. Com...By combining fractal theory with D-S evidence theory, an algorithm based on the fusion of multi-fractal features is presented. Fractal features are extracted, and basic probability assignment function is designed. Comparison and simulation are performed on the new algorithm, the old algorithm based on single feature and the algorithm based on neural network. Results of the comparison and simulation illustrate that the new algorithm is feasible and valid.展开更多
The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is h...The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is helpful for commercial exploitation of CBM. Affected by wellbore flow pressure, initial reservoir pressure, relative permeability, Langmuir pressure and other factors, the trend of declining production of a single CBM well agrees, by and large, with a hyperbolic pattern of decline. Based on Arps’s equation, nearly 200 wells production with different peak yields and initial rates of were simulated. Given the present cost of drill- ing, gas production and engineering on the ground, the gross investment for the development of a single coalbed methane well was estimated for the Fanzhuang block in central China. Considering the current industrial policies for CBM, we established an eco- nomic assessment model and analyzed economic peaks. The results show the economic benefits with or without government subsi- dies at different peak yields of a single CBM well. The results of the evaluation can be directly applied in the Fanzhuang block. The evaluation method, formulated in our study, can be used to other areas with similar conditions.展开更多
An algorithm for estimating the cross-bispectrum of an acoustic vector signal was formulated. Composed features of sound pressure and acoustic vector signals are extracted by the proposed algorithm and other estimatin...An algorithm for estimating the cross-bispectrum of an acoustic vector signal was formulated. Composed features of sound pressure and acoustic vector signals are extracted by the proposed algorithm and other estimating algorithms for secondary and higher order spectra. Its effectiveness was tested with lake and sea trial data. These features can be used to construct an input vector set for a radial basis function neural network. The classification of vessels can then be made based on the extracted features. It was shown that the composed features of acoustic vector signals are more easily divided into categories than those of pressure signals. When using the composed features of acoustic vector signals, the recognition rate of underwater acoustic targets improves.展开更多
When a group of mobile agents track a target,they can locate themselves and the target in a cooperative manner.To maximize the group advantage,a parallel integration strategy of cooperative target-localization(CTL)and...When a group of mobile agents track a target,they can locate themselves and the target in a cooperative manner.To maximize the group advantage,a parallel integration strategy of cooperative target-localization(CTL)and cooperative self-localization(CSL)is designed.Firstly,a global cost function containing the agents’positions and the target’s position is established.Secondly,along with the agents’positions being re-estimated during CTL,the Utransform is employed to propagate the error covariance of the position estimations among the agents.The simulation results show that,the proposal exploits more information for locating the target and the agents than the cases where CTL and CSL run separately,and the global optimal position estimations of the agents and the target are obtained.展开更多
As one of the largest enterprises in China, Zhongyuan Petroleum Exploration Bureau. Sinopec （ZPEB） has become a medium-sized onshore oilfield with its exploration and development for more than thirty years. Its annu...As one of the largest enterprises in China, Zhongyuan Petroleum Exploration Bureau. Sinopec （ZPEB） has become a medium-sized onshore oilfield with its exploration and development for more than thirty years. Its annual output with crude oil of several milliontons and natnral gas of several billion cubicmeters has been kept for two decades.展开更多
文摘For the high altitude cruising flight phase of a hypersonic cruise missile （HCM）, a relative motion mod- el between the missile and the target is established by defining virtual target and combining the theory of the dif- ferential geometry with missile motion equations. Based on the model, the motion between the missile and the tar- get is considered as a single target differential game problem, and a new open-loop differential game midcourse guidance law （DGMGL） is deduced by solving the corresponding Hamiltonian Function. Meanwhile, a new struc- ture of a closed-loop DGMGL is presented and the training data for back propagation neural network （BPNN） are designed. By combining the theory of BPNN with the open-loop DGMGL obtained above, the law intelligence is realized. Finally, simulation is carried out and the validity of the law is testified.
文摘By combining fractal theory with D-S evidence theory, an algorithm based on the fusion of multi-fractal features is presented. Fractal features are extracted, and basic probability assignment function is designed. Comparison and simulation are performed on the new algorithm, the old algorithm based on single feature and the algorithm based on neural network. Results of the comparison and simulation illustrate that the new algorithm is feasible and valid.
基金Project supported by the Creative Foundation for Young-Middle-Aged Researchers from CNPC 2006–2008
文摘The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is helpful for commercial exploitation of CBM. Affected by wellbore flow pressure, initial reservoir pressure, relative permeability, Langmuir pressure and other factors, the trend of declining production of a single CBM well agrees, by and large, with a hyperbolic pattern of decline. Based on Arps’s equation, nearly 200 wells production with different peak yields and initial rates of were simulated. Given the present cost of drill- ing, gas production and engineering on the ground, the gross investment for the development of a single coalbed methane well was estimated for the Fanzhuang block in central China. Considering the current industrial policies for CBM, we established an eco- nomic assessment model and analyzed economic peaks. The results show the economic benefits with or without government subsi- dies at different peak yields of a single CBM well. The results of the evaluation can be directly applied in the Fanzhuang block. The evaluation method, formulated in our study, can be used to other areas with similar conditions.
基金Supported by the National Natural Science Foundation under Grant No.40827003
文摘An algorithm for estimating the cross-bispectrum of an acoustic vector signal was formulated. Composed features of sound pressure and acoustic vector signals are extracted by the proposed algorithm and other estimating algorithms for secondary and higher order spectra. Its effectiveness was tested with lake and sea trial data. These features can be used to construct an input vector set for a radial basis function neural network. The classification of vessels can then be made based on the extracted features. It was shown that the composed features of acoustic vector signals are more easily divided into categories than those of pressure signals. When using the composed features of acoustic vector signals, the recognition rate of underwater acoustic targets improves.
文摘When a group of mobile agents track a target,they can locate themselves and the target in a cooperative manner.To maximize the group advantage,a parallel integration strategy of cooperative target-localization(CTL)and cooperative self-localization(CSL)is designed.Firstly,a global cost function containing the agents’positions and the target’s position is established.Secondly,along with the agents’positions being re-estimated during CTL,the Utransform is employed to propagate the error covariance of the position estimations among the agents.The simulation results show that,the proposal exploits more information for locating the target and the agents than the cases where CTL and CSL run separately,and the global optimal position estimations of the agents and the target are obtained.
文摘As one of the largest enterprises in China, Zhongyuan Petroleum Exploration Bureau. Sinopec （ZPEB） has become a medium-sized onshore oilfield with its exploration and development for more than thirty years. Its annual output with crude oil of several milliontons and natnral gas of several billion cubicmeters has been kept for two decades.
