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
Animals grouping together is one of the most interesting phenomena in population dynamics and different functional responses as a result of prey-predator forming groups have been considered by many authors in their mo...Animals grouping together is one of the most interesting phenomena in population dynamics and different functional responses as a result of prey-predator forming groups have been considered by many authors in their models. In the present paper we have considered a model for one prey and two competing predator populations with time lag and square root functional response on account of herd formation by prey. It is shown that due to the inclusion of another competing predator, the underlying system without delay becomes more stable and limit cycles do not occur naturally. However, after considering the effect of time lag in the basic system, limit cycles appear in the case of all equilibrium points when delay time crosses some critical value. From the numerical simulation, it is observed that the length of delay is minimum when only prey population survives and it is maximum when all the populations coexist.展开更多
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.
文摘Animals grouping together is one of the most interesting phenomena in population dynamics and different functional responses as a result of prey-predator forming groups have been considered by many authors in their models. In the present paper we have considered a model for one prey and two competing predator populations with time lag and square root functional response on account of herd formation by prey. It is shown that due to the inclusion of another competing predator, the underlying system without delay becomes more stable and limit cycles do not occur naturally. However, after considering the effect of time lag in the basic system, limit cycles appear in the case of all equilibrium points when delay time crosses some critical value. From the numerical simulation, it is observed that the length of delay is minimum when only prey population survives and it is maximum when all the populations coexist.
