In mine ventilation networks, the reasonable airflow distribution is very important for the production safety and economy. Three basic problems of the natural, full-controlled and semi-controlled splitting were review...In mine ventilation networks, the reasonable airflow distribution is very important for the production safety and economy. Three basic problems of the natural, full-controlled and semi-controlled splitting were reviewed in the paper. Aiming at the high difficulty semi-controlled splitting problem, the general nonlinear multi-objectives optimization mathematical model with constraints was established based on the theory of mine ventilation networks. A new algorithm, which combined the improved differential evaluation and the critical path method （CPM） based on the multivariable separate solution strategy, was put forward to search for the global optimal solution more efficiently. In each step of evolution, the feasible solutions of air quantity distribution are firstly produced by the improved differential evolu- tion algorithm, and then the optimal solutions of regulator pressure drop are obtained by the CPM. Through finite steps iterations, the optimal solution can be given. In this new algorithm, the population of feasible solutions were sorted and grouped for enhancing the global search ability and the individuals in general group were randomly initialized for keeping diversity. Meanwhile, the individual neighbor- hood in the fine group which may be closely to the optimal solutions were searched locally and slightly for achieving a balance between global searching and local searching, thus improving the convergence rate. The computer program was developed based on this method. Finally, the two ventilation networks with single-fan and multi-fans were solved. The results show that this algorithm has advantages of high effectiveness, fast convergence, good robustness and flexibility. This computer program could be used to solve lar^e-scale ~eneralized ventilation networks o^timization problem in the future.展开更多
A new method to obtain the real height profile of ionospheric electron density is described, which is called 'approximation with network'. Also it has been demonstrated how to solve the group path integral equ...A new method to obtain the real height profile of ionospheric electron density is described, which is called 'approximation with network'. Also it has been demonstrated how to solve the group path integral equation with Back Propagation(BP) neural network, and given the computation results with this method for a parabolic model.Simulation results show that the proposed method is effective.展开更多
The three dimensional ray-path equation considering the effect of the horizontal gradient of the ionospheric electron density is obtained. By integrating in upgoing and downgoing stage, the point on the raypath can be...The three dimensional ray-path equation considering the effect of the horizontal gradient of the ionospheric electron density is obtained. By integrating in upgoing and downgoing stage, the point on the raypath can be determined and the propagation channel in HF radio telecommunication may be recknoed and predicted. Considering the effect of the electron density slope the ray-path is asymmetric about the reflecting point, and the wave is no longer in the great circle determined by the original wave vector. The group path and the phase path can also be solved.展开更多
The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as wel...The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as well as to show severe diseases, abnormal fluctuation, misplaced way and versatile environment confronted by pig breeding in China. The paper establishes ＂double-hug mode＂, from which pig breeding industry transforms and upgrades to modern breeding industry. Combing with the designed multi-party cooperation mechanism of advantageous regions, urban sale areas and group corporations, it sets up three paths for development of pig healthy agriculture in China, i.e., strategic paths of advantageous regions, urban sale areas and group corporations oriented, with an attempt to provide strategic path reference for transformation and upgrading of pig breeding in China and mode reference for breakthrough of development strategy for pig healthy industry.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51134023)
文摘In mine ventilation networks, the reasonable airflow distribution is very important for the production safety and economy. Three basic problems of the natural, full-controlled and semi-controlled splitting were reviewed in the paper. Aiming at the high difficulty semi-controlled splitting problem, the general nonlinear multi-objectives optimization mathematical model with constraints was established based on the theory of mine ventilation networks. A new algorithm, which combined the improved differential evaluation and the critical path method （CPM） based on the multivariable separate solution strategy, was put forward to search for the global optimal solution more efficiently. In each step of evolution, the feasible solutions of air quantity distribution are firstly produced by the improved differential evolu- tion algorithm, and then the optimal solutions of regulator pressure drop are obtained by the CPM. Through finite steps iterations, the optimal solution can be given. In this new algorithm, the population of feasible solutions were sorted and grouped for enhancing the global search ability and the individuals in general group were randomly initialized for keeping diversity. Meanwhile, the individual neighbor- hood in the fine group which may be closely to the optimal solutions were searched locally and slightly for achieving a balance between global searching and local searching, thus improving the convergence rate. The computer program was developed based on this method. Finally, the two ventilation networks with single-fan and multi-fans were solved. The results show that this algorithm has advantages of high effectiveness, fast convergence, good robustness and flexibility. This computer program could be used to solve lar^e-scale ~eneralized ventilation networks o^timization problem in the future.
文摘A new method to obtain the real height profile of ionospheric electron density is described, which is called 'approximation with network'. Also it has been demonstrated how to solve the group path integral equation with Back Propagation(BP) neural network, and given the computation results with this method for a parabolic model.Simulation results show that the proposed method is effective.
文摘The three dimensional ray-path equation considering the effect of the horizontal gradient of the ionospheric electron density is obtained. By integrating in upgoing and downgoing stage, the point on the raypath can be determined and the propagation channel in HF radio telecommunication may be recknoed and predicted. Considering the effect of the electron density slope the ray-path is asymmetric about the reflecting point, and the wave is no longer in the great circle determined by the original wave vector. The group path and the phase path can also be solved.
基金Acknowledgments The authors thank for the support by National Natural Science Foundation of China ＂The Study of Benefits Safeguards of Healthy Pig Breeding Industry and Exemplified Promotion Mechanism＂ （70873125） and by the collaborative project of Scientific Research and Graduate Training of Beijing Municipal Education Commission （Grant 201502911110426）.
文摘The objective of study in the paper was to analyze advantages, disadvantages, opportunities and threats of development of pig healthy agriculture in China, using systematic analysis and SWOT strategic analysis, as well as to show severe diseases, abnormal fluctuation, misplaced way and versatile environment confronted by pig breeding in China. The paper establishes ＂double-hug mode＂, from which pig breeding industry transforms and upgrades to modern breeding industry. Combing with the designed multi-party cooperation mechanism of advantageous regions, urban sale areas and group corporations, it sets up three paths for development of pig healthy agriculture in China, i.e., strategic paths of advantageous regions, urban sale areas and group corporations oriented, with an attempt to provide strategic path reference for transformation and upgrading of pig breeding in China and mode reference for breakthrough of development strategy for pig healthy industry.
