I. Introduction
Distributed constraint optimization (DCOP) problems are problems where agents need to coordinate their value assignments to minimize the sum of the resulting constraint costs [1], [2], [3], [4]. They are well-suited for modeling multiagent coordination problems where the primary interactions are between local subsets of agents, such as the scheduling of meetings [5], the coordination of sensors in networks [6], and the generation of coalition structures [7]. Unfortunately, DCOP problems only model static problems or, in other words, problems that do not change over time. In the above mentioned coordination problems, various events that change the problem can occur. For example, in the scheduling of meetings, new meetings might need to be scheduled, time constraints of meeting participants could have changed, or the priorities of meetings could have changed.