The technology of production planning and scheduling is one of the critical technologies that decide whether the automated manufacturing systems can get the expected economy. Job shop scheduling belongs to the special...The technology of production planning and scheduling is one of the critical technologies that decide whether the automated manufacturing systems can get the expected economy. Job shop scheduling belongs to the special class of NP-hard problems. Most of the algorithms used to optimize this class of problems have an exponential time; that is, the computation time increases exponentially with problem size. In scheduling study, makespan is often considered as the main objective. In this paper, makespan, the due date request of the key jobs, the availability of the key machine, the average wait-time of the jobs, and the similarities between the jobs and so on are taken into account based on the application of mechanical engineering. The job shop scheduling problem with multi-objectives is analyzed and studied by using genetic algorithms based on the mechanics of genetics and natural selection. In this research, the tactics of the coding and decoding and the design of the genetic operators, along with the description of the mathematic model of the multi-objective functions, are presented. Finally an illu-strative example is given to testify the validity of this algorithm.展开更多
In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(...In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(AF-NC), in which each relay adaptively calculates the number of packets having innovative information according to the feedback from the sink. With AF-NC, duplicate packets are not sent, and the total number of time slots needed to complete transmission can be significantly reduced. The second scheme, named adaptive forwarding with network coding and retransmission(AFR-NC), combines AF-NC with automatic repeat request(ARQ) to guarantee reliable end-to-end communication with limited resource occupation. Numerical results show that compared with simple forwarding with network coding(F-NC), AF-NC has close successful delivery rate with dramatically less time slots, while AFR-NC achieves strict reliability with limited resource cost.展开更多
基金Supported by National Information Industry Department (01XK310020)Shanghai Natural Science Foundation (No. 01ZF14004)
文摘The technology of production planning and scheduling is one of the critical technologies that decide whether the automated manufacturing systems can get the expected economy. Job shop scheduling belongs to the special class of NP-hard problems. Most of the algorithms used to optimize this class of problems have an exponential time; that is, the computation time increases exponentially with problem size. In scheduling study, makespan is often considered as the main objective. In this paper, makespan, the due date request of the key jobs, the availability of the key machine, the average wait-time of the jobs, and the similarities between the jobs and so on are taken into account based on the application of mechanical engineering. The job shop scheduling problem with multi-objectives is analyzed and studied by using genetic algorithms based on the mechanics of genetics and natural selection. In this research, the tactics of the coding and decoding and the design of the genetic operators, along with the description of the mathematic model of the multi-objective functions, are presented. Finally an illu-strative example is given to testify the validity of this algorithm.
基金the National Natural Science Foundation of China(Nos.61102051,61221001 and 61301117)the National High Technology Research and Development Program(863)of China(Nos.2012AA011701 and 2012AA121601)+1 种基金the Shanghai Jiao Tong University Science and Technology Innovation Foundation(No.AF0300021)the Shanghai Key Laboratory Funding(No.12DZ2272600)
文摘In this paper, we propose two novel efficient scheduling schemes with network coding in multi-relay wireless network to maximize the transmission efficiency. The first one uses adaptive forwarding with network coding(AF-NC), in which each relay adaptively calculates the number of packets having innovative information according to the feedback from the sink. With AF-NC, duplicate packets are not sent, and the total number of time slots needed to complete transmission can be significantly reduced. The second scheme, named adaptive forwarding with network coding and retransmission(AFR-NC), combines AF-NC with automatic repeat request(ARQ) to guarantee reliable end-to-end communication with limited resource occupation. Numerical results show that compared with simple forwarding with network coding(F-NC), AF-NC has close successful delivery rate with dramatically less time slots, while AFR-NC achieves strict reliability with limited resource cost.
