Ulrich Junker

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Over-constrained problems can have an exponential number of conflicts, which explain the failure, and an exponential number of relaxations, which restore the consistency. A user of an interactive application, however, desires explanations and relaxations containing the most important constraints. To address this need, we define preferred explanations and(More)
Preference programming provides a new paradigm for expressing (default) decisions, preferences between decisions, and search strategies in a declarative and unified way and for embedding them in a constraint and rule language. Business experts can thus directly specify preferences and search directives in form of rules without needing to program search(More)
Column generation is a state of the art method for optimally solving di cult large scale optimization problems such as airline crew as signment We show how to apply column generation even if those prob lems have complex constraints that are beyond the scope of pure OR methods We achieve this by formulating the subproblem as a constraint satisfaction problem(More)
In this pa.per we develop a proof procedure for autoepistemic (AEL) and defalrlt logics (DL), based on translating them into a. Truth Maintenance System (TMS). The translation is decidable if t,he theory consists of a finite number of defaults a.nd premises and classical derivability for the base language is decida.ble. To determine all extensions of a(More)
Many real-world AI problems (e.g. in configuration) are weakly constrained, thus requiring a mechanism for characterizing and finding the preferred solutions. Preference-based search (PBS) exploits preferences between decisions to focus search to preferred solutions, but does not efficiently treat preferences on defined criteria such as the total price or(More)
This paper describes the logic of ILOG (J)Configurator, a powerful configuration system combining constraint programming with a description logic. This combination is based on two key ideas: 1. Constraints are embedded into a logical language and can thus be applied to logical terms formed with the vocabulary of the description logic. 2. When solving the(More)
Preference-based search (PBS) is a new search procedure for solving combinatorial optimization problems. Given a set of preferences between search decisions, PBS searches through a space of preferred solutions, which is tighter than the space of all solutions. The definition of preferred solutions is based on work in non-monotonic reasoning (Brewka 1989;(More)
The European air traffic flow management problem poses particular challenges on optimization technology as it requires detailed modelling and rapid online optimization capabilities. Constraint programming proved successful in addressing these challenges for departure time slot allocation by offering fine-grained modelling of resource constraints and fast(More)