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Showing 2 results for Gravity Model
Approximation Methods for Solving the Equitable Location Problem with Probabilistic Customer Behavior
Jafar Bagherinejad, Maryam Omidbakhsh,
Volume 24, Issue 3 (9-2013)
Abstract
Location-allocation of facilities in service systems is an essential factor of their performance. One of the considerable situations which less addressed in the relevant literature is to balance service among customers in addition to minimize location-allocation costs. This is an important issue, especially in the public sector. Reviewing the recent researches in this field shows that most of them allocated demand customer to the closest facility. While, using probability rules to predict customer behavior when they select the desired facility is more appropriate. In this research, equitable facility location problem based on the gravity rule was investigated. The objective function has been defined as a combination of balancing and cost minimization, keeping in mind some system constraints. To estimate demand volume among facilities, utility function(attraction function) added to model as one constraint. The research problem is modeled as one mixed integer linear programming. Due to the model complexity, two heuristic and genetic algorithms have been developed and compared by exact solutions of small dimension problems. The results of numerical examples show the heuristic approach effectiveness with good-quality solutions in reasonable run time.
An Analysis of the Impacts of COVID-19 and Freight Cost on Trade of the Economic Belt and the Maritime Silk Road
Abd Alwahed Dagestani,
Volume 33, Issue 3 (9-2022)
Abstract
The Coronavirus Disease 2019 (COVID-19) epidemic in China has been controlled periodically. However, we are now in a period of rapid outbreaks worldwide, the situation of epidemic prevention and control in all countries is still tense. Due to the COVID-19 outbreak, objectively, international trade has a higher risk of infection. At this stage, the prevention and control of the epidemic have become a responsibility for the countries worldwide. This study aims to measure the potential economic impacts of COVID-19 on trade volume between China and One Belt One Road countries (OBOR). The economic impacts assessments of (COVID-19) on trade are based on a Gravity model and speed of convergence (SC) method by changes in trading behavior and cost of (COVID -19) outbreak by in affected countries. The results reveal that potential trade values between China and European Union (EU) will drop by 11.5%, China and East Asia and Pacific (EAP) by 6,7%, China and the Middle East and North Africa (MENA) by 8.9%, China and South Asia (SAR) by15%, China and Europe and Central Asia (ECA) by 9%.
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