Sascha Van Cauwelaert

Understanding the Potential of Propagators

Propagation is at the very core of Constraint Programming (CP): it can provide significant performance boosts as long as the search space reduction is not outweighed by the cost for running the propagators. A lot of research effort in the CP community is directed toward improving this trade-off, which for a given type of filtering amounts to reducing the computation cost. This is done chiefly by 1) devising more efficient algorithms or by 2) using on-line control policies to limit the propagator activations. In both cases, obtaining improvements is a long and demanding process with uncertain outcome. We propose a method to assess the potential gain of both approaches before actually starting the endeavor, providing the community with a tool to best direct the research efforts. Our approach is based on instrumenting the constraint solver to collect statistics, and we rely on replaying search trees to obtain more realistic assessments. The overall approach is easy to setup and is showcased on the Energetic Reasoning (ER) and the Revisited Cardinality Reasoning for BinPacking (RCRB) propagators.

Simplifying the development of cross-platform web user interfaces by collaborative model-based design

Ensuring responsive design of web applications requires their user interfaces to be able to adapt according to different contexts of use, which subsume the end users, the devices and platforms used to carry out the interactive tasks, and also the environment in which they occur. To address the challenges posed by responsive design, aiming to simplify their development by factoring out the common parts from the specific ones, this paper presents Quill, a web-based development environment that enables various stakeholders of a web application to collaboratively adopt a model-based design of the user interface for cross-platform deployment. The paper establishes a series of requirements for collaborative model-based design of cross-platform web user interfaces motivated by the literature, observational and situational design. It then elaborates on potential solutions that satisfy these requirements and explains the solution selected for Quill. A user survey has been conducted to determine how stakeholders appreciate model-based design user interface and how they estimate the importance of the requirements that lead to Quill.

The Unary Resource with Transition Times

Transition time constraints are ubiquitous in scheduling problems. They are said to be sequence-dependent if their durations depend on both activities between which they take place. In this context, we propose to extend the

How efficient is a global constraint in practice

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A Visual Web Tool to Perform What-If Analysis of Optimization Approaches.

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A Project-Based Introduction to Agile Software Development

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