Engineering combinatorial optimization algorithms to improve the lifetime of OLED displays

In this thesis, we consider an optimization problem arising in the design of controllers for OLED displays. Our objective is to minimize amplitude of the electrical current through the diodes which has a direct impact on the lifetime of such a display. To this end, we model this problem as an integer linear program. Subsequently, we refine this formulation by exploiting the combinatorial structure of the problem. We establish a general approximation framework based on network flow techniques. We apply an algorithm engineering approach to improve our heuristics by interacting experimental evaluations and theoretical investigations. For example on the theoretical side, we present a fully combinatorial linear-time algorithm for the MAXFLOW problem on graphs with bounded bandwidth and accordingly numbered nodes. With respect to our application, we implement a custom-made version of this algorithm to solve an important subproblem. Finally, we develop fully combinatorial approximation algorithms well suited for being implemented in the hardware of a control device that drives an OLED display. Moreover, our algorithms achieve near optimal solutions in practice yielding significantly longer lifetimes of passive matrix OLED displays.