Tuesday, February 13, 2018
2:00 – 3:00 pm
Speaker: Dr. Jaemyung Ahn, Korea Advanced Institute of Science and Technology
This seminar introduces two routing problems arising in the space exploration applications - the planetary surface exploration and the active debris removal. The first topic deals with a routing problem class referred to as the vehicle routing problem with vector profits (VRPVP). Given a network composed of a depot/sites and arcs among them, the problem determines routes that depart from the depot, visit sites, and return to the depot. It is assumed that there are multiple stakeholders interested in the routing. Each site is associated with a vector whose ith component corresponds to the profit value obtained by the ith stakeholder. The objective of the problem, which is a max-min type, is to maximize the profit sum for the least satisfied stakeholder. An approach based on the linear program (LP) relaxation and the column-generation technique to solve this max-min type routing problem was developed and validated through numerical experiments. Two cases studies - the planetary surface exploration and the Rome tour cases – are presented to demonstrate the effectiveness of the proposed problem formulation and solution methodology.
The second topic is on multi-target rendezvous problem. A two-phase framework to obtain a near-optimal solution of multi-target Lambert rendezvous problem is introduced. The objective of the problem is to determine the minimum-cost/maximum-profit-sum rendezvous sequence and trajectories to visit all/part of a set of targets within given mission duration. The first phase solves a series of single-target rendezvous problems for all departure-arrival object pairs to generate the elementary solutions, which provides candidate rendezvous trajectories. The second phase formulates a variant of routing problem using the elementary solutions prepared in the first phase and determines the final rendezvous sequence and trajectories of the multi-target rendezvous problem. Two case studies on the asteroid exploration and active debris removal are presented to demonstrate the effectiveness of the proposed framework.
Jaemyung Ahn is currently an associate professor of aerospace engineering at the Korea Advanced Institute of Science and Technology (KAIST; Daejeon, South Korea). His research interests include 1) conceptual design of aerospace missions/systems, 2) methodologies to analyze large and complex systems, and 3) flight dynamics of aerial and space vehicles. He worked for Bain & Company as a management consultant helping strategic decisions of clients in various industrial fields (2008 – 2010), and worked for the Korea Aerospace Research Institute involved in the research and development of the first liquid propellant rocket (KSR-III) and launch vehicle (KSLV-I) of South Korea as a systems engineer (1999 – 2004). He received his B.S. and M.S. degrees from Seoul National University in 1997 and 1999, respectively, and a Ph.D. in aeronautics and astronautics from MIT in 2008.