6 research outputs found
Human-Centred Feasibility Restoration
Decision systems for solving real-world combinatorial problems must be able to report infeasibility in such a way that users can understand the reasons behind it, and understand how to modify the problem to restore feasibility. Current methods mainly focus on reporting one or more subsets of the problem constraints that cause infeasibility. Methods that also show users how to restore feasibility tend to be less flexible and/or problem-dependent. We describe a problem-independent approach to feasibility restoration that combines existing techniques from the literature in novel ways to yield meaningful, useful, practical and flexible user support. We evaluate the resulting framework on two real-world applications
Using Small MUSes to Explain How to Solve Pen and Paper Puzzles
In this paper, we present Demystify, a general tool for creating
human-interpretable step-by-step explanations of how to solve a wide range of
pen and paper puzzles from a high-level logical description. Demystify is based
on Minimal Unsatisfiable Subsets (MUSes), which allow Demystify to solve
puzzles as a series of logical deductions by identifying which parts of the
puzzle are required to progress. This paper makes three contributions over
previous work. First, we provide a generic input language, based on the Essence
constraint language, which allows us to easily use MUSes to solve a much wider
range of pen and paper puzzles. Second, we demonstrate that the explanations
that Demystify produces match those provided by humans by comparing our results
with those provided independently by puzzle experts on a range of puzzles. We
compare Demystify to published guides for solving a range of different pen and
paper puzzles and show that by using MUSes, Demystify produces solving
strategies which closely match human-produced guides to solving those same
puzzles (on average 89% of the time). Finally, we introduce a new randomised
algorithm to find MUSes for more difficult puzzles. This algorithm is focused
on optimised search for individual small MUSes
Taming complexity of industrial printing systems using a constraint-based DSL: An industrial experience report
Flexible printing systems are highly complex systems that consist of printers, that print individual sheets of paper, and finishing equipment, that processes sheets after printing, for example, assembling a book. Integrating finishing equipment with printers involves the development of control software that configures the devices, taking hardware constraints into account. This control software is highly complex to realize due to (1) the intertwined nature of printing and finishing, (2) the large variety of print products and production options for a given product, and (3) the large range of finishers produced by different vendors. We have developed a domain-specific language called CSX that offers an interface to constraint solving specific to the printing domain. We use it to model printing and finishing devices and to automatically derive constraint solver-based environments for automatic configuration. We evaluate CSX on its coverage of the printing domain in an industrial context, and we report on lessons learned on using a constraint-based DSL in an industrial context