3 Février - 9 Février

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Mardi 4 Février
Heure: 12:00 - 13:30
Lieu: Salle B107, bâtiment B, Université de Villetaneuse
Résumé: Capacity Planning for Natural Gas Transmission Networks
Description: Jesco Humpola We present a procedure for capacity planning of large-scale real-world
natural gas distribution networks. It decides which combination of
network extensions such as additional pipelines, compressors or valves
should be added to increase the network's capacity or enhance its
operational flexibility. We formulate this as a mixed-integer nonlinear
problem. A sub-problem has different convex reformulations. Hence we use
a combination of linear outer approximation and NLP solution techniques
to solve the MINLP. We show that every dual solution of the convex
reformulations allows to generate capacity inequalities (or cutting
planes) which reduce the overall solution time when added to the
formulation. The dual solution also enables the measurement of
infeasibility level of the scenario. Furthermore we give a primal
heuristic for our model. We present computational results that are
obtained by a special tailored version of the solvers SCIP and IPOPT.
Vendredi 7 Février
Heure: 00:59 - 12:00
Lieu: Salle B107, bâtiment B, Université de Villetaneuse
Résumé: Models of a Non-Associative Composition
Description: Guillaume Munch-Maccagnoni We characterise the
polarised evaluation order through a categorical structure where the
hypothesis that composition is associative is relaxed. Duploid is
the name of the structure, as a reference to Jean-Louis Loday's duplicial
algebras. The main result is a reflection Adj→Dupl where Dupl
is a category of duploids and duploid functors, and Adj is the
category of adjunctions and pseudo maps of adjunctions. The result suggests
that the various biases in denotational semantics:
indirect, call-by-value, call-by-name... are a way of hiding the fact that
composition is not always associative.