A Travel Recommender System for Combining Multiple Travel Regions to a Composite Trip

Internet-based services are available to recommend destinations and activities for organized trips. Only few systems support travelers when creating composite trips consisting of multiple destinations or activities. The idea in this work is to select travel regions that maximize the value of the composite trip for the user while still respecting her limitations in time and money. The value of a travel region can be determined by the similarity between a specified user query and the cases in a travel region database. The recommendation algorithm needs to find a decent routing between the regions while still satisfying diversity of the whole trip. We developed an algorithm based on an approximation for the knapsack problem and extended it to recognize dependencies between the regions while calculating best combinations. It is able to determine the optimal duration of stay per region and its performance improves when benefiting from the hierarchical structure of our travel database. In an expert study, we verified the results of our approach. The study proves that our algorithm for composite trips delivers good recommendations which satisfied an expert user more than baseline algorithms. Regions in the composite trip fit together better and a decent routing between the regions can be ensured. Nevertheless, the algorithm leaves room for improvement by combining less similar regions in a composite trip, thus leading to a higher diversity of the recommendation.