Topic B.2: Multi-objective decision support for hierarchical production planning in recycling cascades

Since decision-making models with multiple objectives often describe reality better than a single objective-oriented decision-making model, various approaches to multi-criteria decision support were developed, which are often tailor-made for concrete problem formulations. Multi-objective decision models are generally divided into two classes, namely multi-attribute decision making (MADM) for discrete alternatives, and multi-objective decision making (MODM) for continuous solution spaces (Figueira et al., 2005). There are suitable MODM methods (Miettinen, 1999; Jahn, 2004) to describe the various criteria for designing innovative production processes and networks, as well as assessing their resource efficiency. Since there are strategic as well as operational planning issues in the production networks that need solving, the hierarchical production planning offers a suitable conceptual framework (Kistner, Steven, 1991; Walther, 2005; Walther, 2010). These methods have, however, not yet been applied to the operational planning of innovative production processes and value-creating networks for renewable resources.

Consequently, hierarchical production planning models are applied for selected key products’ cascade utilization (see topic A.4) and are extended and implemented with regard to multiple objective targets (see topic C.4). From a mathematical standpoint, the development of algorithms (see topic B.6) that find efficient solutions within a reasonable computing time is a challenge, as a sound (manageable) representative system must be selected from a large number of efficient solutions. In this context, we can partially draw on our preliminary work, such as the simultaneous planning of biogas power plants and heating systems in bioenergy villages (Schmehl et al., 2010), multi-criteria assessments in the energy sector (Ludwig et al., 2009; Oberschmidt et al., 2010), in the transport sector networks (Ginkel, Schöbel, 2007), as well as in comparison to integrated and hierarchical planning in the transport sector (Schmidt, Schöbel, 2010). Close and methodical co-operation with topics B.1, B.3, and B.6 regarding adequate consideration of planning uncertainty is essential.