This paper focuses on the 2-median location improvement problem on tree networks and the problem is to modify the weights of edges at the minimum cost such that the overall sum of the weighted distance of the vertices...This paper focuses on the 2-median location improvement problem on tree networks and the problem is to modify the weights of edges at the minimum cost such that the overall sum of the weighted distance of the vertices to the respective closest one of two prescribed vertices in the modified network is upper bounded by a given value.l1 norm and l∞norm are used to measure the total modification cost. These two problems have a strong practical application background and important theoretical research value. It is shown that such problems can be transformed into a series of sum-type and bottleneck-type continuous knapsack problems respectively.Based on the property of the optimal solution two O n2 algorithms for solving the two problems are proposed where n is the number of vertices on the tree.展开更多
The Paris Agreement introduced a 1.5 ℃ target to control the rise in global temperature, but clear arrangements for feasible implementation pathways were not made. Achieving the 1.5 ℃ target imposes high requirement...The Paris Agreement introduced a 1.5 ℃ target to control the rise in global temperature, but clear arrangements for feasible implementation pathways were not made. Achieving the 1.5 ℃ target imposes high requirements on global emission reduction. Nationally Determined Con- tributions of all Parties are far from the 1.5 ℃ target, and conventional emission reduction technologies and policies will also have difficulty in fulfilling this task. In this context, geoengineering is gaining interest in the international arena. The Paris Agreement includes afforestation, carbon capture, utilization and storage, and negative emission technologies such as bio-energy with carbon capture and store. All of these techniques are CO2 removal technologies that belong to geoengineering. Solar radiation management, which is highly controversial, has also attracted increased attention in recent years. Although the outline of the IPCC Special Report on 1.5 ℃ does not include a specific section on geoengineering issues yet, geoengineering is an unconventional technical option that cannot be avoided in research and discussions on impact assessment, technical options, ethics, and international governance under the 1.5 ℃ target. On the basis of analyzing and discussing abovementioned issues, this paper proposes several policy suggestions for China to strengthen research on and response to geoengineering.展开更多
In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in t...In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in the set of optimal control variables.展开更多
基金The National Natural Science Foundation of China(No.10801031)
文摘This paper focuses on the 2-median location improvement problem on tree networks and the problem is to modify the weights of edges at the minimum cost such that the overall sum of the weighted distance of the vertices to the respective closest one of two prescribed vertices in the modified network is upper bounded by a given value.l1 norm and l∞norm are used to measure the total modification cost. These two problems have a strong practical application background and important theoretical research value. It is shown that such problems can be transformed into a series of sum-type and bottleneck-type continuous knapsack problems respectively.Based on the property of the optimal solution two O n2 algorithms for solving the two problems are proposed where n is the number of vertices on the tree.
文摘The Paris Agreement introduced a 1.5 ℃ target to control the rise in global temperature, but clear arrangements for feasible implementation pathways were not made. Achieving the 1.5 ℃ target imposes high requirements on global emission reduction. Nationally Determined Con- tributions of all Parties are far from the 1.5 ℃ target, and conventional emission reduction technologies and policies will also have difficulty in fulfilling this task. In this context, geoengineering is gaining interest in the international arena. The Paris Agreement includes afforestation, carbon capture, utilization and storage, and negative emission technologies such as bio-energy with carbon capture and store. All of these techniques are CO2 removal technologies that belong to geoengineering. Solar radiation management, which is highly controversial, has also attracted increased attention in recent years. Although the outline of the IPCC Special Report on 1.5 ℃ does not include a specific section on geoengineering issues yet, geoengineering is an unconventional technical option that cannot be avoided in research and discussions on impact assessment, technical options, ethics, and international governance under the 1.5 ℃ target. On the basis of analyzing and discussing abovementioned issues, this paper proposes several policy suggestions for China to strengthen research on and response to geoengineering.
文摘In this paper, we discuss relations between optimal stopping problems over tree sets and partially ordered sets, prove that there is a 1-1 correspondence between them and so every optimal strategy can be obtained in the set of optimal control variables.
