Everyone is welcome to attend the GCOE Colloquium
- Meiji institute for Advanced Study of Mathematical Science (MIMS)
- GCOE Colloquium is partly supported by, the Meiji University Global COE program “Formation and Development of Mathematical Sciences Based on Modeling and Analysis”
Access to IKUTA Campus:
- http://www.meiji.ac.jp/koho/campus_guide/ikuta/access.html (in Japanese)
- http://gcoe.mims.meiji.ac.jp/eng/access/index.html (in English)
GCOE Colloquium (No. 025) 
Date: Feb. 15. 2013 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
Campus map in Japanese in EnglishYong Jung KIM
(Korea Advanced Institute of Science and Technology, KAIST)"Starvation driven dispersal as a survival strategy for biological organisms"
Abstract:
Dispersal strategy is a key element in the evolution of biological species and each of them has developed its own strategy. The actual ecological dispersal strategies of species are results of exceptionally long history of evolution and hence are all successful ones that provide the species a chance to survive. The motility of species is changed considerably depending on the needs of food or mating and such a change is the key to understand the role of dispersal. In this talk we will discuss how to model such a dispersal and what properties do such models have. Numerical simulations are also compared.
GCOE Colloquium (No. 024)
Date: Nov. 29. 2012 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Pascal CHOSSAT
(Directeur de Recherche au CNRS Laboratoire Jean-Alexandre Dieudonné)"Modelling the perception of textures by the visual cortex :
a structure tensor approach."Abstract:
Experiments conducted 40 years ago have shown that the images formed on the retina of mammals such as cat and primates are isomorphically mapped through a complicated pathway to a region of the visual cortex called primary V1 area. Moreover it has been shown that this region is paved with small domains called "hypercolumns", in which neurons are selectively sensitive to the orientation of contours in the portion of image mapped to the hypercolumn. This has led to the so-called "ring model" of Wilson and Cowan (1973), which is a neural field equation on V1 with an additional angular variable accounting for the orientation. Recently I proposed with Olivier Faugeras (INRIA Sophia Antipolis) to improve this model by replacing the angular variable with the "structure tensor", an object widely used in image processing and artificial vision to better take account of the texture of the images: contours, corners, contrast... Structure tensors live in a Riemann space with a hyperbolic structure. This new model leads to a Wilson-Cowan type of equations which however is now defined on the hyperbolic space of structure tensors (in addition to the position coordinates). The analysis of these equations can be further reduced to the hyperbolic plane (or Poincaré disc). Their bifurcation analysis then requires the use of Helgason's theory of Fourier analysis in the Poincaré disc and Fuchsian group formalism. It leads to original results on pattern formation.
I shall present the model, the methodology and some results as well as open questions about this new approach to texture perception by the visual cortex.
GCOE Colloquium (No. 023)
Date: Oct. 17. 2012 14:40-16:10
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Campus map in Japanese in EnglishHisao Honda (Hyogo University)
GCOE Colloquium (No. 022)
Date: Jul. 30. 2012 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Juan Manuel García-Ruiz
(Instituto Andaluz de Ciencias de la Tierra / CSIC-Universidad de Granada)"Inorganic routes to self-assembled materials with complex shapes"
Abstract:
The morphology of crystals is controlled by their growth environment and their crystal structure. The structural control restricts the symmetry of any crystal shape to one of the 32 point-symmetry groups (35 when quasicrystals are considered). Crystal structure also imposes discrete angles between faces and discards the possibility of shapes with continuous curvature. To break this constriction, life has developed several strategies to built crystalline complex morphologies with continuous curvature but hierarchical textural organization. The formation of such architectures is usually directed by organic molecules or matrices and it is thought they are privative of life and distinguish biogenic shapes from their inanimate, mostly euhedral counterparts. In this lecture, I will review the existence of chemical routes to complex shapes with continuous curvature made of purely inorganic materials. One of them, called silica biomorphs, are simply made by precipitation of alkaline-earth carbonates in silica-rich media. Thus, aggregates of highly oriented carbonate nanocrystals can be obtained, which display striking non-crystallographic morphologies that mimic primitive life forms [1]. These precipitates are made of millions of nanocrystals that self-assemble expanding the symmetry of the crystalline phase 2/m 2/m 2/m, and forming first fractal aggregates, then two-dimensional lamellae and finally threedimensional complex morphologies with non-crystallographic symmetry. I will present the details of the morphogenesis of these materials at a phenomenological level [2,3] and will propose a plausible physico-chemical explication based on coupling of silica-carbonate precipitation. Finally, I will comment new advances in other type of inorganic route to materials with complex shapes, such as silica gardens [4] and Liesegang rings.[1] J.M. García-Ruiz, et al., Science 302 (2003) 1194.
[2] J. M. García-Ruiz, et al., Science 323 (2009) 362.
[3] M. Kellermeier, et al, Chemistry A European Journal, 18 (2012) 2272.
[4] F. Glaab et al., Angewandte Chemie, 124 (2012) 4316.
GCOE Colloquium (No. 021)
Date: Jul. 11. 2012 17:00-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A306
Ryohei Kanzaki
(Research Center for Advanced Science and Technology, the University of Tokyo)
GCOE Colloquium (No. 020)
Date: June. 19. 2012 17:30-18:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A302
Hideki Takayasu
(Meiji University /Sony Computer Science Laboratories, Inc.)
GCOE Colloquium (No. 019)
Date: Jan 12. 2012 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A206
Jong-Shenq GUO (Meiji University / Tamkang University, Taiwan)
PROPAGATION AND BLOCKING IN PERIODICALLY HOSTILE ENVIRONMENTS
Abstract:
We study the persistence and propagation (or blocking) phenomena for a species in periodically hostile environments. The problem is described by a reactiondiffusion equation with zero Dirichlet boundary condition. We first derive the existence of a minimal nonnegative nontrivial stationary solution and study the large-time behavior of the solution of the initial boundary value problem. Then we provide a simple geometric condition for the blocking of propagation and we derive the asymptotic behavior of the approximated pulsating traveling fronts. Moreover, for the case of constant diffusion matrix, we provide two conditions for which the limit of approximated minimal speeds is positive.
This talk is based on a joint work with Francois Hamel.
GCOE Colloquium (No. 018)
Date: Dec. 8. 2011 17:00-18:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A416
Hiroshi FUJITA (Professor emeritus at the University of Tokyo)
GCOE Colloquium (No. 017)
Date: Oct. 24. 2011 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
Masafumi KAMACHI (Meteorological Research Institute)
GCOE Colloquium (No. 016)
Date: Sep. 26. 2011 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
Campus map in Japanese in EnglishMasako BANDO (NPO network; "EINSTEIN")
GCOE Colloquium (No. 015)
【CANCELLED】
Date: Mar 24. 2011 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A306
"SINGLE PHYTOPLANKTON SPECIES GROWTH WITH LIGHT AND ADVECTION IN A WATER COLUMN" - Joint work with Yuan Lou -
Sze-Bi Hsu (National Tsing-HuaUniversity)
GCOE Colloquium (No. 014)
Date: Dec. 10. 2010 16:30-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A306
Campus map in Japanese in EnglishTakashi WASHIO (Osaka University)
Satoshi HARA (Graduate School, Osaka University)
GCOE Colloquium (No. 013)
Date: Nov 29. 2010 16:30-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A306
Toru OHIRA (Sony Computer Science Laboratories, Inc.)
GCOE Colloquium (No. 012)
Date: Jul 23. 2010 16:30-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Norio KONNO (Yokohama National University)
GCOE Colloquium (No. 011)
Date: May 21. 2010 16:30-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
Masahisa TABATA (Waseda University)
GCOE Colloquium (No. 010)
Date: Apr 15. 2010 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
16:30-17:30
Kazuyuki AIHARA (University of Tokyo)
GCOE Colloquium (No. 009)
Date: Mar 9. 2010 15:30-17:40
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
15:30-16:30
Genshiro KITAGAWA (The Institute of Statistical Mathematics)16:40-17:40
Kohei OHTSU (Tokyo University of Marine Science and Technology)
GCOE Colloquium (No. 008)
Date: Feb 19. 2010 16:00-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A206
16:00-16:45
Hiroshi KOIZUMI (Graduate School, The University of Tokyo)17:00-18:00
Kokichi SUGIHARA (Meiji University)
GCOE Colloquium (No. 007)
Date: Jan 26. 2010 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Yoh IWASA (Kyushu University)
GCOE Colloquium (No. 006)
Date: Dec 7. 2009 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
Shin-ichi UYE (Hiroshima University)
GCOE Colloquium (No. 005)
Date: Nov 6. 2009 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
Homei MIYASHITA (Meiji University)
GCOE Colloquium (No. 004)
Date: Oct 23. 2009 16:30-17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A309
Kaoru ARAKAWA (Meiji University)
GCOE Colloquium (No. 003)
Date: Aug 27. 2009 16:00-18:00
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A401
16:00-17:00
Akihiko OHBA (Nomura Securities Global Quantitative Research)17:00-18:00
Mitsugu MATSUSHITA (Chuo University)
GCOE Colloquium (No. 002)
Date: Jul 27. 2009 15:00-16:30
Location: Shikon-Kan, Surugadai Campus (Tokyo), Meiji Univ.
Takashi YANAGAWA (Kurume University)
GCOE Colloquium (No. 001)
Date: Jun 23. 2009 15:00~17:30
Location: Meiji Univ. Ikuta Campus Build 2 Annex A Room A207
15:00 ー16:00
Hidenori YASUDA (Josai University)16:30 ー17:30
Chiyori URABE (Meiji University, Research Promoter)
