Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensi...Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.展开更多
The China’s Earthquake Cases and Disaster Information System based on GIS (MapECDIS 2002 for Windows) is a GIS system developed to provide a tool for the government and the public to inquire and learn about disaster ...The China’s Earthquake Cases and Disaster Information System based on GIS (MapECDIS 2002 for Windows) is a GIS system developed to provide a tool for the government and the public to inquire and learn about disaster information (since 2221BC) and case study results (since 1966) of destructive earthquakes in China. The system is expected to be helpful, as an applied supplementary tool, for scientists and management personnel in earthquake prediction practice, seismological research and earthquake disaster research. The design idea and main functions of the system are introduced in the paper.展开更多
The optimization models and algorithms with their implementations on flow over time problems have been an emerging field of research because of largely increasing human-created and natural disasters worldwide.For an o...The optimization models and algorithms with their implementations on flow over time problems have been an emerging field of research because of largely increasing human-created and natural disasters worldwide.For an optimal use of transportation network to shift affected people and normalize the disastrous situation as quickly and efficiently as possible,contraflow configuration is one of the highly applicable operations research(OR)models.It increases the outbound road capacities by reversing the direction of arcs towards the safe destinations that not only minimize the congestion and increase the flow but also decrease the evacuation time significantly.In this paper,we sketch the state of quickest flow solutions and solve the quickest contraflow problem with constant transit times on arcs proving that the problem can be solved in strongly polynomial time O(nm^2(long n)~2)where n and m are number of nodes and number of arcs,respectively in the network.This contraflow solution has the same computational time bound as that of the best min-cost flow solution.Moreover,we also introduce the contraflow approach with load dependent transit times on arcs and present an efficient algorithm to solve the quickest contraflow problem approximately.Supporting the claim,our computational experiments on Kathmandu road network and on randomly generated instances perform very well matching the theoretical results.For a sufficiently large number of evacuees,about double flow can be shifted with the same evacuation time and about half time is sufficient to push the given flow value with contraflow reconfiguration.展开更多
基金Projects 50574072, 50874089 and 50534049 supported by the National Natural Science Foundation of China08JK366 by the Special Scientific Foundation of Educational Committee of Shaanxi Province
文摘Based on catastrophe theory,we used the catastrophe progression method to predict the risk of coal and gas outbursts in coal mines.According to the major factors affecting coal and gas outbursts,we built a comprehensive evaluation index system and a coal and gas outburst prediction model.In addition,we performed a standard transformation for each index system;based on the degree the various indices affect the risk of an outburst,to make the data dimensionless.Based on the outburst data from eight mines,we determined catastrophe progression values and verified these values.The results show that:1) converting multi-dimensional problems into one-dimensional problems using this catastrophe progression method can simplify the steps of predicting coal and gas outbursts;2) when pre-determined catastrophe progression values are used to predict coal and gas outbursts,the predicting accuracy rate can be as high as 87.5%;3) the various coal mines have different factors inducing outbursts with varying importance of these factors and 4) the catastrophe progression values,calculated based on these factors,can be used effectively to predict the risk of outbursts in coal mines.
文摘The China’s Earthquake Cases and Disaster Information System based on GIS (MapECDIS 2002 for Windows) is a GIS system developed to provide a tool for the government and the public to inquire and learn about disaster information (since 2221BC) and case study results (since 1966) of destructive earthquakes in China. The system is expected to be helpful, as an applied supplementary tool, for scientists and management personnel in earthquake prediction practice, seismological research and earthquake disaster research. The design idea and main functions of the system are introduced in the paper.
基金supported by Deutscher Akademischer Austauschdienst (German Academic Exchange Service) Partnership Program (with University of Kaiserslautern, Germany and Mindanao State University, Iligan Institute of Technology, Iligan, Philippines)Av H Research Group Linkage Program (with Technische Universitt Bergakademie Freiberg) in Graph Theory and Optimization at Central Department of Mathematics, Tribhuvan University, Kathmandu, Nepalsupported by the Av H Foundation for the Georg Forster Research Fellowship for post doctoral researchers at Technische Universitt Bergakademie Freiberg Germany
文摘The optimization models and algorithms with their implementations on flow over time problems have been an emerging field of research because of largely increasing human-created and natural disasters worldwide.For an optimal use of transportation network to shift affected people and normalize the disastrous situation as quickly and efficiently as possible,contraflow configuration is one of the highly applicable operations research(OR)models.It increases the outbound road capacities by reversing the direction of arcs towards the safe destinations that not only minimize the congestion and increase the flow but also decrease the evacuation time significantly.In this paper,we sketch the state of quickest flow solutions and solve the quickest contraflow problem with constant transit times on arcs proving that the problem can be solved in strongly polynomial time O(nm^2(long n)~2)where n and m are number of nodes and number of arcs,respectively in the network.This contraflow solution has the same computational time bound as that of the best min-cost flow solution.Moreover,we also introduce the contraflow approach with load dependent transit times on arcs and present an efficient algorithm to solve the quickest contraflow problem approximately.Supporting the claim,our computational experiments on Kathmandu road network and on randomly generated instances perform very well matching the theoretical results.For a sufficiently large number of evacuees,about double flow can be shifted with the same evacuation time and about half time is sufficient to push the given flow value with contraflow reconfiguration.
