Cédric Verbeeck

A fast solution method for the time-dependent orienteering problem

This paper introduces a fast solution procedure to solve 100-node instances of the time-dependent orienteering problem (TD-OP) within a few seconds of computation time. Orienteering problems occur in logistic situations were an optimal combination of locations needs to be selected and the routing between the selected locations needs to be optimized. In the time-dependent variant, the travel time between two locations depends on the departure time at the first location. Next to a mathematical formulation of the TD-OP, the main contribution of this paper is the design of a fast and effective algorithm to tackle this problem. This algorithm combines the principles of an ant colony system (ACS) with a time-dependent local search procedure equipped with a local evaluation metric. Additionally, realistic benchmark instances with varying size and properties are constructed. The average score gap with the known optimal solution on these test instances is only 1.4% with an average computation time of 0.5seconds. An extensive sensitivity analysis shows that the performance of the algorithm is insensitive to small changes in its parameter settings.

Solving the stochastic time-dependent orienteering problem with time windows

This paper introduces the stochastic time-dependent orienteering problem with time windows. The orienteering problem occurs in logistic situations where an optimal combination of locations must first be selected and then the routing between these selected locations must be optimized. In the stochastic time-dependent variant, the travel time between two locations is a stochastic function that depends on the departure time at the first location. The main contribution of this paper lies in the design of a fast and effective algorithm to solve this challenging problem. To validate the performance and the practical relevance of this proposed algorithm, several experiments were carried out on realistic benchmark instances of varying size and properties. These benchmark instances are constructed based on an actual large road network in Belgium with historic travel time profiles for every road segment.

The Time-Dependent Orienteering Problem with Time Windows: A Fast Ant Colony System

This paper proposes a fast ant colony system based solution method to solve realistic instances of the time-dependent orienteering problem with time windows within a few seconds of computation time. Orienteering problems occur in logistic situations where an optimal combination of locations needs to be selected and the routing between these selected locations needs to be optimized. For the time-dependent problem, the travel time between two locations depends on the departure time at the first location. The main contribution of this paper is the design of a fast and effective algorithm for this problem. Numerous experiments on realistic benchmark instances with varying size confirm the state-of-the-art performance and practical relevance of the algorithm.