For the deficiency that the traditional single forecast methods could not forecast electronic equipment states, a combined forecast method based on the hidden Markov model（HMM） and least square support vector machin...For the deficiency that the traditional single forecast methods could not forecast electronic equipment states, a combined forecast method based on the hidden Markov model（HMM） and least square support vector machine（LS-SVM） is presented. The multi-agent genetic algorithm（MAGA） is used to estimate parameters of HMM to overcome the problem that the Baum-Welch algorithm is easy to fall into local optimal solution. The state condition probability is introduced into the HMM modeling process to reduce the effect of uncertain factors. MAGA is used to estimate parameters of LS-SVM. Moreover, pruning algorithms are used to estimate parameters to get the sparse approximation of LS-SVM so as to increase the ranging performance. On the basis of these, the combined forecast model of electronic equipment states is established. The example results show the superiority of the combined forecast model in terms of forecast precision,calculation speed and stability.展开更多
The accurate and timely traffic state prediction has become increasingly important for the traffic participants,especially for the traffic managements. In this paper,the traffic state is described by Micro-LOS,and a d...The accurate and timely traffic state prediction has become increasingly important for the traffic participants,especially for the traffic managements. In this paper,the traffic state is described by Micro-LOS,and a direct prediction method is introduced. The development of the proposed method is based on Maximum Entropy (ME) models trained for multiple modes. In the Multimode Maximum Entropy (MME) framework,the different features like temporal and spatial features of traffic systems,regional traffic state are integrated simultaneously,and the different state behaviors based on 14 traffic modes defined by average speed according to the date-time division are also dealt with. The experiments based on the real data in Beijing expressway prove that the MME models outperforms the already existing model in both effectiveness and robustness.展开更多
This paper focuses on the “state of the art” research of the Argentinian zonda wind at the beginning of 2015. Zonda (similar to foehn) is a strong, warm, very dry wind associated with adiabatic compression upon desc...This paper focuses on the “state of the art” research of the Argentinian zonda wind at the beginning of 2015. Zonda (similar to foehn) is a strong, warm, very dry wind associated with adiabatic compression upon descending the eastern slopes of the Andes Cordillera in western central Argentina. Particularly, hourly surface meteorological information obtained from the Argentine National Weather Service (Servicio Meteorológico Nacional, SMN) from Mendoza Aero (32?50’S, 68?47’W, 704 m ASL) and San Juan Aero (31?34’S, 68?25’W, 598 m ASL) airport meteorological stations was used. The paper contains a history of zonda research mentioning the principal papers since the 1950s, the characteristics of zonda wind (conceptual model, a classic event, intensities categories) and examples of non-classical episodes. Also zonda dynamics, zonda climatology and forecasting problems are considered. A probabilistic method and the model forecast that are running in operative way are commented. Also the climate impact, air quality and damages caused are mentioned. There has been substantial progress in the understanding of this kind of complex wind during the last years, especially since the last decade, accelerated using different models. This paper has highlighted some of these advances by synthesizing some of the major findings. The probabilistic prediction method developed in the 1980s is still very useful to predict zonda in the cities of San Juan and Mendoza. This as well as the new available tools, such as the eta/PRM and GEM models running operatively (continuously) at PRM (Mendoza Regional Meteorology Program), offered the community the possibility to generate an Early Warning System to warn the population particularly in its severe manifestations. The answer to questions regarding time of onset of the event, place where it will occur first, duration, intensity and offset still poses a great challenge for researchers and forecasters in the region.展开更多
Land use change is a very complex process of evolution.On the basis of the principle of cellular automata,this article presents a kind of method that we can first mine state transition rule from historical map data,an...Land use change is a very complex process of evolution.On the basis of the principle of cellular automata,this article presents a kind of method that we can first mine state transition rule from historical map data,and then conduct forecast by virtue of Monte-Carlo method,achieving spatial dynamic forecast from map to map.We interpret TM remote sensing image in Ji'nan City in 2004 and 2006 to get present land use map for empirical research,and forecast land use map in 2012 and 2016,respectively.Studies show that this method of using spatial data to mine state transition rule,has advantages of simpleness,accuracy,strong real-time characteristic etc.in the simulation of dynamic change of land use,the results of which are roughly in line with the actual results,therefore,it can provide reference for land use planning.展开更多
文摘For the deficiency that the traditional single forecast methods could not forecast electronic equipment states, a combined forecast method based on the hidden Markov model（HMM） and least square support vector machine（LS-SVM） is presented. The multi-agent genetic algorithm（MAGA） is used to estimate parameters of HMM to overcome the problem that the Baum-Welch algorithm is easy to fall into local optimal solution. The state condition probability is introduced into the HMM modeling process to reduce the effect of uncertain factors. MAGA is used to estimate parameters of LS-SVM. Moreover, pruning algorithms are used to estimate parameters to get the sparse approximation of LS-SVM so as to increase the ranging performance. On the basis of these, the combined forecast model of electronic equipment states is established. The example results show the superiority of the combined forecast model in terms of forecast precision,calculation speed and stability.
基金supported by Beijing Science Foundation Plan Project(Grant No.D07020601400707)the National High Technology Re-search and Development Program of China(Grant NO.2006AA11Z231)
文摘The accurate and timely traffic state prediction has become increasingly important for the traffic participants,especially for the traffic managements. In this paper,the traffic state is described by Micro-LOS,and a direct prediction method is introduced. The development of the proposed method is based on Maximum Entropy (ME) models trained for multiple modes. In the Multimode Maximum Entropy (MME) framework,the different features like temporal and spatial features of traffic systems,regional traffic state are integrated simultaneously,and the different state behaviors based on 14 traffic modes defined by average speed according to the date-time division are also dealt with. The experiments based on the real data in Beijing expressway prove that the MME models outperforms the already existing model in both effectiveness and robustness.
文摘This paper focuses on the “state of the art” research of the Argentinian zonda wind at the beginning of 2015. Zonda (similar to foehn) is a strong, warm, very dry wind associated with adiabatic compression upon descending the eastern slopes of the Andes Cordillera in western central Argentina. Particularly, hourly surface meteorological information obtained from the Argentine National Weather Service (Servicio Meteorológico Nacional, SMN) from Mendoza Aero (32?50’S, 68?47’W, 704 m ASL) and San Juan Aero (31?34’S, 68?25’W, 598 m ASL) airport meteorological stations was used. The paper contains a history of zonda research mentioning the principal papers since the 1950s, the characteristics of zonda wind (conceptual model, a classic event, intensities categories) and examples of non-classical episodes. Also zonda dynamics, zonda climatology and forecasting problems are considered. A probabilistic method and the model forecast that are running in operative way are commented. Also the climate impact, air quality and damages caused are mentioned. There has been substantial progress in the understanding of this kind of complex wind during the last years, especially since the last decade, accelerated using different models. This paper has highlighted some of these advances by synthesizing some of the major findings. The probabilistic prediction method developed in the 1980s is still very useful to predict zonda in the cities of San Juan and Mendoza. This as well as the new available tools, such as the eta/PRM and GEM models running operatively (continuously) at PRM (Mendoza Regional Meteorology Program), offered the community the possibility to generate an Early Warning System to warn the population particularly in its severe manifestations. The answer to questions regarding time of onset of the event, place where it will occur first, duration, intensity and offset still poses a great challenge for researchers and forecasters in the region.
基金Supported by National Natural Science Foundation (40571119)Shandong Natural Science Foundation (Y2007E05)
文摘Land use change is a very complex process of evolution.On the basis of the principle of cellular automata,this article presents a kind of method that we can first mine state transition rule from historical map data,and then conduct forecast by virtue of Monte-Carlo method,achieving spatial dynamic forecast from map to map.We interpret TM remote sensing image in Ji'nan City in 2004 and 2006 to get present land use map for empirical research,and forecast land use map in 2012 and 2016,respectively.Studies show that this method of using spatial data to mine state transition rule,has advantages of simpleness,accuracy,strong real-time characteristic etc.in the simulation of dynamic change of land use,the results of which are roughly in line with the actual results,therefore,it can provide reference for land use planning.
