Parham Azimi,; Mohammad Reza ghanbari,*
Volume 13, Issue 38 , October 2015, , Pages 133-161
Abstract
Considering the increasing demand for operational activities in ports, ports managers are facing the challenge of optimal usage of port facilities and equipment. (In the last two decades, maritime transportation systems have been experienced an increasing development. Now the rate of development in this ...
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Considering the increasing demand for operational activities in ports, ports managers are facing the challenge of optimal usage of port facilities and equipment. (In the last two decades, maritime transportation systems have been experienced an increasing development. Now the rate of development in this section has been reached 8 percent per year. Nowadays, the port managers are faced with the challenge of optimal use of equipment and facilities). One of these challenges is to reduce the waiting times of ships at the ports.so that in this study, placing the buffer area for loading and unloading cereals has been investigated using a simulation optimization model based on queuing theory at SHAHID RAJAEE port. Three important criteria of the port performance have been considered including the ship turn-around time, number of loaded ships and loading norm. The results indicate that optimization of cereal transportation between the buffer area and the port can increase the capacity of transportation and loading- unloading capacity up to (The results show that the proposed model can increase the capacity of loading and unloading of the system up to %15.5between the port and buffer area.)
Hasan Shavandi; Mehdi Mardane Khameneh
Volume 8, Issue 20 , March 2011, , Pages 27-48
Abstract
On the networks existing servers and customers, each node indicates a customer demand and demand rate is estimated for them. The edges of the network indicate connective ways among the nods which is usually shown with the distance of two nods or the time of travelling. In the covering location problems, ...
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On the networks existing servers and customers, each node indicates a customer demand and demand rate is estimated for them. The edges of the network indicate connective ways among the nods which is usually shown with the distance of two nods or the time of travelling. In the covering location problems, the objective is locating some of the servers on the network in a way that the customers' demand supported by the maximum covering of the servers and optimized objective criterion. In this research the location model with Probability Structure, which the probability of choosing servers by customer is estimated based on their distance, is developed. In the presented model, supposing there is a competitive market, lost demand is considered, too. And according to the mentioned matter the objective of the model is to minimize the cost of losing demands or to maximize the earned profits of responding to the demands. Then, we propose a genetic algorithm (GA) to solve this model. In addition, we employ design of experiments and response surface methodology to both tune the GA parameters and to evaluate the performance of the proposed method in 45 test problems. The results of the performance analysis show that the efficiency of the proposed GA method is very well.
