Parallel machine scheduling problems, which are important discrete optimization problems, may occur in many applications. For example, load balancing in network communication channel assignment, parallel processing in...Parallel machine scheduling problems, which are important discrete optimization problems, may occur in many applications. For example, load balancing in network communication channel assignment, parallel processing in large-size computing, task arrangement in flexible manufacturing systems, etc., are multiprocessor scheduling problem. In the traditional parallel machine scheduling problems, it is assumed that the problems are considered in offline or online environment. But in practice, problems are often not really offline or online but somehow in-between. This means that, with respect to the online problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi-online ones. In this paper, the semi-online problem P2|decr|lp (p>1) is considered where jobs come in non-increasing order of their processing times and the objective is to minimize the sum of the lp norm of every machine’s load. It is shown that LS algorithm is optimal for any lp norm, which extends the results known in the literature. Furthermore, randomized lower bounds for the problems P2|online|lp and P2|decr|lp are presented.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
The optimality of a fuzzy logic alternative to the usual treatment of uncertainties in a scheduling system using fuzzy numbers is examined formally. Processing times and due dates are fuzzified and presented by fuzzy ...The optimality of a fuzzy logic alternative to the usual treatment of uncertainties in a scheduling system using fuzzy numbers is examined formally. Processing times and due dates are fuzzified and presented by fuzzy numbers. With introducing the necessity measure, we compare fuzzy completion times of jobs with fuzzy due dates to decide whether jobs are tardy. The object is to minimize the numbers of tardy jobs. The efficient solution method for this problem is proposed. And deterministic counterpart of this single machine scheduling problem is a special case of fuzzy version.展开更多
It is considered here for an improved ant algorithm to minimize the delivery time of VRP （Vehicle Routing Problem） in distribution center. Firstly VRP which objective is to minimize the delivery time is given, then ...It is considered here for an improved ant algorithm to minimize the delivery time of VRP （Vehicle Routing Problem） in distribution center. Firstly VRP which objective is to minimize the delivery time is given, then the optimal vehicle distributionroute-division approach of distribution center for given customer array is defined, and the ant colony algorithm for VRP with objective to minimize the delivery time is presented. The research of this paper is based on the information and application case of tobacco network in Hangzhou city. By investigating, we created two different system models. One is division of distribution route of distribution center, and the other is optimization of single vehicle route. The computational example tests and verifys the solution.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 10271110 10301028) and the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE+2 种基金 China Project supported by the National Natural Science Foundation of China (Nos. 10271110 10301028) and the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE China
文摘Parallel machine scheduling problems, which are important discrete optimization problems, may occur in many applications. For example, load balancing in network communication channel assignment, parallel processing in large-size computing, task arrangement in flexible manufacturing systems, etc., are multiprocessor scheduling problem. In the traditional parallel machine scheduling problems, it is assumed that the problems are considered in offline or online environment. But in practice, problems are often not really offline or online but somehow in-between. This means that, with respect to the online problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi-online ones. In this paper, the semi-online problem P2|decr|lp (p>1) is considered where jobs come in non-increasing order of their processing times and the objective is to minimize the sum of the lp norm of every machine’s load. It is shown that LS algorithm is optimal for any lp norm, which extends the results known in the literature. Furthermore, randomized lower bounds for the problems P2|online|lp and P2|decr|lp are presented.
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The optimality of a fuzzy logic alternative to the usual treatment of uncertainties in a scheduling system using fuzzy numbers is examined formally. Processing times and due dates are fuzzified and presented by fuzzy numbers. With introducing the necessity measure, we compare fuzzy completion times of jobs with fuzzy due dates to decide whether jobs are tardy. The object is to minimize the numbers of tardy jobs. The efficient solution method for this problem is proposed. And deterministic counterpart of this single machine scheduling problem is a special case of fuzzy version.
文摘It is considered here for an improved ant algorithm to minimize the delivery time of VRP （Vehicle Routing Problem） in distribution center. Firstly VRP which objective is to minimize the delivery time is given, then the optimal vehicle distributionroute-division approach of distribution center for given customer array is defined, and the ant colony algorithm for VRP with objective to minimize the delivery time is presented. The research of this paper is based on the information and application case of tobacco network in Hangzhou city. By investigating, we created two different system models. One is division of distribution route of distribution center, and the other is optimization of single vehicle route. The computational example tests and verifys the solution.
