Learning Interpretable Error Functions for Combinatorial Optimization Problem Modeling

In Constraint Programming, constraints are usually represented as predicates allowing or forbidding combinations of values. However, some algorithms exploit a finer representation: error functions. Their usage comes with a price though: it makes problem modeling significantly harder. Here, we propose a method to automatically learn an error function corresponding to a constraint, given a function deciding if assignments are valid or not. This is, to the best of our knowledge, the first attempt to automatically learn error functions for hard constraints. Our method uses a variant of neural networks we named Interpretable Compositional Networks, allowing us to get interpretable results, unlike regular artificial neural networks. Experiments on 5 different constraints show that our system can learn functions that scale to high dimensions, and can learn fairly good functions over incomplete spaces

Multiplex flows in citation networks

Abstract Knowledge is created and transmitted through generations, and innovation is often seen as a process generated from collective intelligence. There is rising interest in studying how innovation emerges from the blending of accumulated knowledge, and from which path an innovation mostly inherits. A citation network can be seen as a perfect example of one generative process leading to innovation. However, the impact and influence of scientific publication are always difficult to capture and measure. We offer a new take on investigating how the knowledge circulates and is transmitted, inspired by the notion of “stream of knowledge”. We propose to look at this question under the lens of flows in directed acyclic graphs (DAGs). In this framework inspired by the work of Strahler, we can also account for other well known measures of influence such as the h-index. We propose then to analyze flows of influence in a citation networks as an ascending flow. From this point on, we can take a finer look at the diffusion of knowledge through the lens of a multiplex network. In this network, each citation of a specific work constitutes one layer of interaction. Within our framework, we design three measures of multiplex flows in DAGs, namely the aggregated, sum and selective flow, to better understand how citations are influenced. We conduct our experiments with the arXiv HEP-Th dataset, and find insights through the visualization of these multiplex networks

GHOST: A Combinatorial Optimization Solver for RTS-related Problems

This paper presents GHOST, a combinatorial optimization solver an RTS AI developer can use as a blackbox to solve any problems encoded by a constraint satisfaction/optimization problem. We show a way to model three very different RTS problems by a constraint satisfaction/optimization problem, each problem belonging to a specific level of abstraction, and test our solver on them, using StarCraft as a testbed. For the three problems (the target selection problem, the wall-ion problem and the build order planning problem), GHOST shows very good results computed within some tens of milliseconds. Game AI

A 36,000-Year-Old Volcanic Eruption Depicted in the Chauvet-Pont d'Arc Cave (Ardèche, France)?

International audienceAmong the paintings and engravings found in the Chauvet-Pont d'Arc cave (Ardèche, France), several peculiar spray-shape signs have been previously described in the Megalo-ceros Gallery. Here we document the occurrence of strombolian volcanic activity located 35 km northwest of the cave, and visible from the hills above the cave entrance. The volcanic eruptions were dated, using 40 Ar/ 39 Ar, between 29 ± 10 ka and 35 ± 8 ka (2σ), which overlaps with the 14 C AMS and thermoluminescence ages of the first Aurignacian occupations of the cave in the Megaloceros Gallery. Our work provides the first evidence of an intense volcanic activity between 40 and 30 ka in the Bas-Vivarais region, and it is very likely that Humans living in the Ardèche river area witnessed one or several eruptions. We propose that the spray-shape signs found in the Chauvet-Pont d'Arc cave could be the oldest known depiction of a volcanic eruption, predating by more than 34 ka the description by Pliny the Younger of the Vesuvius eruption (AD 79) and by 28 ka the Çatalhöyük mural discovered in central Turkey

The Chauvet-Pont d’Arc cave and the Bas-Vivarais volcanic field.

<p>(A) Digital elevation model of France (Courtesy NASA/JPL-Caltech) showing the MIS 2–3 active volcanoes and the Chauvet-Pont d’Arc cave; C.P: Chaîne de Puys; B.V: Bas-Vivarais. (B) Digital elevation model of the Bas-Vivarais and Ardèche (Courtesy NASA/JPL-Caltech). The volcanic centers investigated are highlighted in bold italic fonts. (C) Detail of the spray-shape sign engraving from the Megaloceros panel. (D) View from the plateau above the Chauvet-Pont d’Arc cave showing several strombolian cones located 35 km Northwest (Courtesy NASA/JPL-Caltech).</p

Plateau spectra for the three volcanic centers dated.

<p>Uncertainties are given at the 2σ level. Plateau steps are plotted at the 1σ level.</p

Example of a spray-shape sign from Chauvet-Pont d’Arc cave compared to the oldest known depictions of volcanic eruptions.

<p>(A) Map of the Chauvet-Pont d’Arc cave. (B) General view of the Megaloceros panel. The green dot marks the location of the ¹⁴C AMS date [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146621#pone.0146621.ref008" target="_blank">8</a>] (picture credit D. Genty). (C) Detail of the Megaloceros panel chronological succession [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146621#pone.0146621.ref008" target="_blank">8</a>] (pictures credit V. Feruglio-D. Baffier). (D) Petroglyphs depicting the Porak volcano eruption and dated from the 5^th millennium BC in the Syunik region of Armenia [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146621#pone.0146621.ref003" target="_blank">3</a>]. The figure is similar to [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146621#pone.0146621.ref003" target="_blank">3</a>] but not identical to the original image, and is therefore for illustrative purposes only. (E) Çatalhöyük mural painting (Turkey) considered the oldest depiction of a volcanic eruption dated from the 8^th/7^th millennium BC [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146621#pone.0146621.ref001" target="_blank">1</a>].</p