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Séminaires à venir


- Daniel GONCALVES - LIRMM à Montpellier - Every 3-colorable planar graphs is the intersection graph of some segments having slope in (0 , pi/3 , 2 pi/3)

Jeudi 29 juin 2017 - 13 h 00 - Salle du Conseil - Bâtiment ISIMA

Possibilité de visio-conférence

We will present the proof of the above theorem, which partially answers a question raised by De Fraysseix and Ossona de Mendez. Their open problem is, "Is every $k$-colorable planar graph the intersection graph of segments using $k$ slopes ?". It was known to hold for $k=2$. Here we prove the case $k=3$. The case $k=4$ is open and is also known as West’s conjecture. As in these intersection models, parallel segments are expected to be pairwise disjoint, this conjecture generalizes both the 4-color theorem and the fact that every planar graph is an intersection graph of segments.

A crucial point in our proof is the use of a system of linear equations, which provides a scheme of the solution. It is shown that this system always has a (unique) solution by studying the perfect matchings of some related planar graph.

At the end of the talk we will briefly discuss how West’s conjecture could be tackled using a similar approach.


- Anan Phonphoem - KU, Thaïlande - Wireless Network Application for Wildlife Conservation and Disaster Monitoring

Jeudi 9 juillet 2017 - 13 h 00 - Salle du Conseil - Bâtiment ISIMA

Possibilité de visio-conférence

This talk will provide the examples of wireless application in the
Wildlife Conservation and Disaster Monitoring. For Wildlife
Conservation, the camera trap with wireless trigger capability and
smart patrol system will be presented. The landslides
monitoring/alarming system deployed in Krabi province, Thailand, will
be explained as the example of wireless sensor network deployment in
Disaster area.


- Oscar Salviano Silva Filho - PUC, Brésil -

Jeudi 9 juillet 2017 - 14 h 00 - Salle du Conseil - Bâtiment ISIMA

Possibilité de visio-conférence


- Frédéric Andres - NII, Japon -

Jeudi 9 juillet 2017 - 14 h 30 - Salle du Conseil - Bâtiment ISIMA

Possibilité de visio-conférence