Saudi Arabia every year receives more than two million Muslims from all over the world to perform the Hajj, the Muslim pilgrimage to Makkah. It must take place during a specific period of the year in a specific and li...Saudi Arabia every year receives more than two million Muslims from all over the world to perform the Hajj, the Muslim pilgrimage to Makkah. It must take place during a specific period of the year in a specific and limited space. In spite of the effort government agencies devote to this event, a variety of disasters usually take place each year. As the number of pilgrims is increasing every year the problem is becoming an alarming one. More and more resources are allocated to eliminate the occurrence of such disasters. More than one strategy has been proposed to make the Hajj as safe as possible. Knowing that the problem is very complex as it involves numerous actors, and many entangled criteria and elements, the question is which strategy is best. This paper presents the Analytic Network Process as a sound methodology for structuring the Hajj problem by designing an analytical model to find which strategy to focus on to make the pilgrimage as safe as possible.展开更多
Under the demand of strategic air traffic flow management and the concept of trajectory based operations（TBO）,the network-wide 4D flight trajectories planning（N4DFTP） problem has been investigated with the purpose...Under the demand of strategic air traffic flow management and the concept of trajectory based operations（TBO）,the network-wide 4D flight trajectories planning（N4DFTP） problem has been investigated with the purpose of safely and efficiently allocating 4D trajectories（4DTs）（3D position and time） for all the flights in the whole airway network.Considering that the introduction of large-scale 4DTs inevitably increases the problem complexity,an efficient model for strategiclevel conflict management is developed in this paper.Specifically,a bi-objective N4 DFTP problem that aims to minimize both potential conflicts and the trajectory cost is formulated.In consideration of the large-scale,high-complexity,and multi-objective characteristics of the N4DFTP problem,a multi-objective multi-memetic algorithm（MOMMA） that incorporates an evolutionary global search framework together with three problem-specific local search operators is implemented.It is capable of rapidly and effectively allocating 4DTs via rerouting,target time controlling,and flight level changing.Additionally,to balance the ability of exploitation and exploration of the algorithm,a special hybridization scheme is adopted for the integration of local and global search.Empirical studies using real air traffic data in China with different network complexities show that the proposed MOMMA is effective to solve the N4 DFTP problem.The solutions achieved are competitive for elaborate decision support under a TBO environment.展开更多
文摘Saudi Arabia every year receives more than two million Muslims from all over the world to perform the Hajj, the Muslim pilgrimage to Makkah. It must take place during a specific period of the year in a specific and limited space. In spite of the effort government agencies devote to this event, a variety of disasters usually take place each year. As the number of pilgrims is increasing every year the problem is becoming an alarming one. More and more resources are allocated to eliminate the occurrence of such disasters. More than one strategy has been proposed to make the Hajj as safe as possible. Knowing that the problem is very complex as it involves numerous actors, and many entangled criteria and elements, the question is which strategy is best. This paper presents the Analytic Network Process as a sound methodology for structuring the Hajj problem by designing an analytical model to find which strategy to focus on to make the pilgrimage as safe as possible.
基金co-supported by the National Science Foundation for Young Scientists of China(No.61401011)the National Key Technologies R&D Program of China(No.2015BAG15B01)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.61521091)
文摘Under the demand of strategic air traffic flow management and the concept of trajectory based operations（TBO）,the network-wide 4D flight trajectories planning（N4DFTP） problem has been investigated with the purpose of safely and efficiently allocating 4D trajectories（4DTs）（3D position and time） for all the flights in the whole airway network.Considering that the introduction of large-scale 4DTs inevitably increases the problem complexity,an efficient model for strategiclevel conflict management is developed in this paper.Specifically,a bi-objective N4 DFTP problem that aims to minimize both potential conflicts and the trajectory cost is formulated.In consideration of the large-scale,high-complexity,and multi-objective characteristics of the N4DFTP problem,a multi-objective multi-memetic algorithm（MOMMA） that incorporates an evolutionary global search framework together with three problem-specific local search operators is implemented.It is capable of rapidly and effectively allocating 4DTs via rerouting,target time controlling,and flight level changing.Additionally,to balance the ability of exploitation and exploration of the algorithm,a special hybridization scheme is adopted for the integration of local and global search.Empirical studies using real air traffic data in China with different network complexities show that the proposed MOMMA is effective to solve the N4 DFTP problem.The solutions achieved are competitive for elaborate decision support under a TBO environment.
