@Unpublished{2018:Pandey:Hybrid,
      AUTHOR = {Pandey, Ashutosh and Ruchkin, Ivan and Schmerl, Bradley and C\'{a}mara, Javier and Garlan, David},
      TITLE = {Formalizing the Hybrid Planning Problem for Self-Adaptation},
      YEAR = {2019},
      ABSTRACT = {Planning approaches in self-adaptation face the fundamental trade-off between quality and timeliness of adaptation plans. Due to this trade-off, today designers often have to compromise between a planning approach that is quick to find a plan and an approach that is slow but finds a quality plan. To deal with this trade-off, researchers have proposed a hybrid planning approach that combines more than one planning approaches to find a balance between quality and timeliness. However, the diversity of planning approaches makes the problem of hybrid planning complex and multi-faceted. This paper advances the theory of hybrid planning by formalizing the central concepts and four subproblems of hybrid planning. This formalization can serve as a foundation for not only understanding and comparing existing hybrid planners, but also for developing new hybrid planners in the future. Moreover, to illustrate practicality of the formal model, the paper uses it to analyze two hybrid planning instantiations that have shown to effective in their respective contexts. Furthermore, grounded on the formal model, the paper formalizes explicit/implicit assumptions about these instantiations that must hold for them to be sound.},
      NOTE = {Submitted for publication},
      KEYWORDS = {Formal Methods, Planning, Self-adaptation}
}