An optimization approach for green tourist trip design

In this paper, the Multi-Objective Multi-Modal Green Tourist Trip Design Problem (MO-MM-GTTDP) as the multi-modal variant of the orienteering problem is investigated. For this problem, a Multi-Objective mixed-integer linear model is formulated, which maximizes the total score of the Trip, minimizes the total cost of the trip as well as the total emission produced in the trip. Various transportation modes are considered for the tourist to choose to move between points of interest (POIs). The tourist choice may be affected by the transportation time and cost. Moreover, choosing the transportation mode will have an impact on the amount of trip pollutants. The cost of visiting POIs, as well as the cost of transportation between POIs, is considered as the total cost of the tour. In addition, a Multi-Objective Variable Neighborhood Search (MOVNS) algorithm is designed to solve instances of this problem. Moreover, a, E - constraint method is implemented in CPLEX and used to evaluate the performance of the presented MOVNS. New instances of the problem are generated based on the existed benchmark OP instances. The conclusion is the high quality of the proposed MOVNS algorithm solutions in practically acceptable computation time (few seconds). Finally, a small case study based on real data on several POIs in the city of Tehran is generated and used to demonstrate the performance of the proposed model and algorithm in practice. For this case study, by using the multi-attribute decision-making method of TOPSIS, the obtained non-dominated solutions are ranked, and the best ones are presented to the tourist.