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## Description

The
project „Multicriteria Optimisation“ considers mathematical
questions and discrete problems within the CRC 1026 „Sustainable
Manufacturing“. The three sustainability dimensions „economic“,
„environmental“ and „social“, respectively, are considered as
different objective functions by the project A5. Hence, discrete
problems and mathematical questions are modelled by a feasible space
of solutions and several objectives which have to be optimised
simultaneously. In contrast to the single-criteria case, it is
generally not possible to find a solution which optimises all
considered objectives simultaneously. Instead one has to deal with
trade-offs. For example, the cheapest way to manufacture a certain
amount of bicycle frames might not be the environmentally friendliest.
A solution that can be improved in at least one objective without
getting worse off in the other is called inefficient and will
generally be neglected by a decision maker. Hence, only the efficient
solutions are interesting from a decision maker’s point of view.
Besides the mathematical questions about the existence and number of
efficient solutions and the algorithmic approaches of how to compute
them, the project A5 is also concerned with the modelling of
quantitative problems within the CRC 1026. With respect to models the
focus and expertise is on mixed integer programming.

We have
developed PolySCIP, an open-source and freely available solver which
aims at solving multicriteria mixed integer programs with an arbitrary
number of objectives. With respect to scenario analysis two tools,
tech-con and field-con, were implemented. Exemplary applications like
the optimization of process chains for bicycle frame manufacturing,
the selection of sustainable welding processes and design decision
support are documented.

Mehr zu Herausforderungen, Ansätzen und
Ergebnissen von Projekt A5 finden Sie in dieser
Powerpoint-Präsentation (englisch)

**Results from the first funding period**

Project A5 develops PolySCIP (link), a solver for multicriteria
linear and multicriteria (mixed) integer problems.

Scenario
Tool

Two software-tools for the creation of surrounding
field scenarios on the one hand (Clustering with „FieldCon“) and
creation of technology scenarios (system creation with „TechCon“)
on the other hand can be downloaded. These tools have been developed
in cooperation of the projects A1 and A5.

„FieldCon“
for creation of surrounding field scenarios

Surrounding field
scenarios are used to depict different future developments, the so
called scenarios. For this purpose the approach of clustering of key
factors of the surrounding field, which show a strong connection, is
used.

„TechCon“ for creation of technology scenarios

Technology scenarios are used to find useful and sustainable
combinations of system elements to systems. This allows for example
the technical reasonable and sustainable combination of alternative
technologies.

Please click here to download the tools.

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