CEOC had finished its activities in the end of 2009


CEOC (Centre for Research on Optimization and Control) had finished its activities in the end of 2009 and this webpage contains an archive of the work that had been done.

CEOC was a research unit created in 2002 and a member of the Research Institute of the University of Aveiro since 2003. It was working until the end of 2009 when, joining the Mathematics and Applications Research Unit, started in 2010 a new research center:


CIDMA - Center for Research & Development in Mathematics and Applications

Seminar "Funções Especiais do Cálculo Fraccionário e a Função de Mittag-Leffler com Três Parâmetros"

Em 30 de Outubro de 2009, (Departamento de Matemática, sala Sousa Pinto,
11:30-12:30)
Orador: Edmundo Capelas de Oliveira, Departamento de Matemática Aplicada,
Universidade de Campinas, Brasil.
Abstract: Apresentamos uma demonstração formal de um novo teorema envolvendo
a função de Mittag-Leffler com três parâmetros. Como consequência,
recuperamos resultados conhecidos e discutimos um corolário que emerge
naturalmente. Como uma aplicação obtemos a solução de uma equação
diferencial fracionária associada ao circuito elétrico RLC numa forma
fechada envolvendo uma função de Mittag-Leffler com dois parâmetros.

seminar "Eigenvalue statistics of non-Hermitian random"

22 de Outubro de 2009 (Departamento de Matemática, sala Sousa Pinto,
10:00-11:00)
Boris Khoruzhenko, Queen Mary, University of London.
Abstract: In this talk I intend to discuss generic patterns of the
eigenvalue distribution in the complex plane for Gaussian random matrices
with no symmetry conditions imposed. For such matrices the mean eigenvalue
density and higher order correlation functions can be exactly reduced to
twopoint kernels. This makes it possible to analyse the eigenvalue
distribution in the strongly and weakly non-Hermitian limits of large matrix
size. No previous knowledge of random matrix theory will be assumed.

Seminar "Machine Learning and Neuroscience"

6 de Outubro, Departamento de Matemática, sala Sousa Pinto, 12:00-13:00

Title: "Machine Learning and Neuroscience*

Speakers: Concha Bielza and Pedro Larrañaga  (Universidad Politécnica de Madrid

Abstract

Reverse-engineer the human brain has been identified by the National Academy of Engineering in 2009 as one of the 14 challenges that will influence science and technology for the next decade. This calls engineers and neuroscientists to work together. As participants of the Blue Brain international project, in this talk we will describe a number of interesting problems where Machine Learning and Neuroscience can collaborate. They are briefly explained below.

*A.* Define distinct populations of neurons in the brain cortex according to electrophysiological, molecular and morphological features.

This involves a supervised classification to distinguish between the common pyramidal neurons and interneurons or an unsupervised classification that discovers new groups of neurons inside these two classes, whose identity remains unclear.

*B.* Construct models that can simulate the huge variety of dendritic morphology, the shape of brain cells. Dendritic branching is poorly understood due to be driven by a complex process but understanding how these trees are formed in the brain, we can learn more about their normal function and why they are often malformed in neurological diseases. Virtual trees can be created by measuring from real cells different parameters controlling branching behaviour. These measures can be modelled as statistical distributions and a global simulation model accounts for all the parameters together.

*C.* Accurately reconstruct (semi-)automatically the 3D structure and connectivity of neurological tissue and label dendrites, axons and synapses unambiguously from electron microscope images that can provide a level of detail never reached before. It requires a huge amount of data to be processed (hundreds of terabytes) where machine learning and image processing techniques have to be combined.

*D.* The technique of functional magnetic resonance imaging (fMRI) provides high-contrast images of neuronal activity indicating variations in oxygen consumption. The source data are 3D pixels (voxels) representing different intensities. With brain images, we can identify regions of the ventral-occipital cortex involved in visual processing of objects or faces and predict neural activation while identifying pictures and words. A visionary approach would be to use fMRI to diagnose neurodegenerative diseases like Alzheimer's. Difficulties arise due to the joint use of clinical data and spatial, temporal and function information.

*E.* In the same spirit, Alzheimer's disease data and results from different -omics (genomics, proteomics, metabolomics) may be integrated into a single research to study the possible influences and interactions among them. These include DNA microarrays, SNP chips, mass spectrometry runs... that when combined, can open a major degree of knowledge discovery for the Alzheimer's disease.

*F.* Identify and solve some classes of optimization problems in neuronal modelling. The difficulty of the problems may lead to use evolutionary computation based on machine learning models. We identify three classes: (1) neuronal parameter optimization, where we search for the parameter values that yield a desired electrical activity pattern in a neuron (or neuronal network); (2) neuronal model selection, where besides the parameters we also optimize some of the structural components of the model (useful when an accurate formulation of the neuronal model is unavailable); and (3) structural optimization problems in brain networks, where a network topology satisfying a number of constraints has to be found. Brain activity can be modelled as a dynamic process acting on a network, with brain areas, groups of neurons or individual cells as vertices. Its topology may be a key element in understanding the behaviour of the process.

 

(online publication) Isoperimetric problems on time scales with nabla derivatives

Ricardo Almeida and Delfim F. M. Torres, Isoperimetric problems on time
scales with nabla derivatives, Journal of Vibration and Control 2009,
doi:10.1177/1077546309103268

[Seminarios-CEOC] CONNECTED GRAPHS OF FIXED ORDER AND SIZE WITH MAXIMAL Q-INDEX: SOME SPECTRAL BOUNDS.

Orador: Milica Anđelić, Universidade de Aveiro.
The Q−index (or spectral radius) of a simple graph is the largest eigenvalue of its signless Laplacian matrix. There are many results in the literature where, for some fixed class of graphs, all graphs whose index is maximal are identified. For connected graphs of fixed order and size this problem is not yet completely resolved (in contrast to the more general class when connectivity is not required). It is only known (for a long time) that the graphs with maximal Q−index in the former class (and the latter one) are the nested split graphs.
Focusing our attention on eigenvector techniques we got some new (lower and upper) bounds on the Q−index of nested split graphs.
2000 Mathematical Subject Classification: 05C50
Key words and phrases: signless Laplacian spectrum, largest eigenvalue,
spectral radius, graph Q−index, spectral bounds.
13 de Março de 2009, 11:30 - 12:30 - Sala Sousa Pinto, DMat, Universidade de Aveiro

(dissertação de mestrado) Computação no Cálculo das Variações

A aluna Célia Teresa Ligeiro Mendes Pereira defendeu com sucesso a sua dissertação
orientada por João Pedro Cruz e Delfim F.M. Torres em 05/Março/2009.

(regular seminar) eXVisXML, uma ferramenta emblemática na análise documental

Oradores: Pedro Henriques e Daniela da Cruz, Departamento de Informática,
Univ. do Minho
A análise de documentos estruturados, como é o caso dos documentos anotados
em XML, é fundamental para a sua compreensão que é requerida em todas as
tarefas de manutenção e reutilização. A manutenção é exigida no dia-a-dia
para corrigir defeitos, precaver problemas e adicionar funcionalidades. A
reutilização mostra-se relevante para economia de custos e rentabilização.
(...)
6 de Março de 2009, (Departamento de Matemática, sala Sousa Pinto,
11:30-12:30)

(local seminar) Report on my recent visit to Acoustics Research

Evgeny Lakshtanov, Univ. de Aveiro
Abstract: Recently I had a short scientific visit to the acoustics research
institute in Vienna. My objective was to communicate
with mathematicians who work closely with sound engineers in order to pick
up some statements of interesting mathematical problems. During this talk I
intend to share the results of this experience.
27 de Fevereiro de 2009, (Departamento de Matemática, sala Sousa Pinto,
11:30-12:30)

(regular seminar) An asymptotic approach to conjugate time for bangbang

Orador: Cristiana J. Silva, Univ. de Aveiro.
Resumo: We focus on the minimal time control problem for
single-input control-affine systems dx/dt = X(x) + u1 Y1(x) in Rn, where the
scalar control u1 fulfills the constraint |u1()|=<1.
We recall the concept of conjugate time for the bang-bang case in these
systems and propose an asymptotic approach, based on a penalized procedure,
which allows the application of the well-known results (theoretical and
practical) on the conjugate times for the smooth case into the bang-bang
case.
SEMINÁRIO - 20 de Fevereiro de 2009 (Departamento de Matemática, sala Sousa
Pinto, 11:30-12:30)

(computer application) A Computational Approach to Essential and Nonessential Objective Functions in Linear Multicriteria Optimization

Agnieszka B. Malinowska and Delfim F. M. Torres, A Computational Approach to
Essential and Nonessential Objective Functions in Linear Multicriteria
Optimization, Application Type: Maple Worksheet; Publish date: December,
2008; Published by: Maplesoft, a division of Waterloo Maple Inc.
http://www.maplesoft.com/applications/app_center_view.aspx?AID=2374

The Control Theory Group (cotg)

The Control Theory Group (cotg)
receives two new post-docs beginning March 1, 2009:

1) Dr. Ewa Pawluszewicz,
Assistant Professor at the Institute
of Mathematics of Bialystok Technical University, Poland,
Programa da FCT Ciência 2007,
(Concurso Internacional para a Contratação de 1000 Doutorados
para Instituições Científicas Portuguesas, referência C2007-UA/CEOC/03),
Title of the working programme: Control Theory on Time Scales.
Responsible: Delfim F. M. Torres

2) Dr. Ewa Girejko,
Post-doctoral Grant from FCT: SFRH/BPD/48439/2008
Title of the working programme:
Generalized differentials in dynamical inclusions
on time scales and optimal control
Responsible: Delfim F. M. Torres

(seminar) Calculus of Variations on Time Scales,

Delfim F. M. Torres, Calculus of Variations on Time Scales,
Seminários de Matemática,
Seminário de Análise, Geometria e Física-Matemática,
Universidade do Minho, Campus de Gualtar, Braga,
22 de Janeiro de 2009.

(publication) Existence of solutions to a "water-oil" system

M. R. Sidi Ammi, Existence of solutions to a "water-oil" system, PAMM,
Volume 7, Issue 1 , Pages2040081 - 2040082 Copyright C 2007 WILEY-VCH Verlag
GmbH & Co. KGaA, Weinheim
(http://www3.interscience.wiley.com/journal/121560471/abstract)
Published Online: Dec 12 2008 7:37AM
DOI: 10.1002/pamm.200701109

invited talk: "Transversality conditions in the calculus of variations on time scales"

Agnieszka B. Malinowska will give an invited talk at the conference PROGRESS
ON DIFFERENCE EQUATIONS 2009 (PODE09), CONFERENCE IN HONOUR OF PROFESSOR
GERASIMOS LADAS, entitled
Transversality conditions in the calculus of variations on time scales
PODE09 conference will take place in The Mathematical Research and
Conference Center in Bedlewo, Poland, from May 25th to May 29th 2009.
The conference will be locally supported by Stefan Banach International
Mathematical Center, and by Poznan University of Technology.
The proceedings of PODE09 will be published as a special issue of FASCICULI
MATHEMATICI.

invited talk at the conference PROGRESS ON DIFFERENCE EQUATIONS 2009

Delfim F. M. Torres will give an invited talk at the conference PROGRESS ON
DIFFERENCE EQUATIONS 2009 (PODE09), CONFERENCE IN HONOUR OF PROFESSOR
GERASIMOS LADAS, entitled
Unifying the Unifiable Calculus of Variations on Time Scales
PODE09 conference will take place in The Mathematical Research and
Conference Center in Bedlewo, Poland, from May 25th to May 29th 2009.
The conference will be locally supported by Stefan Banach International
Mathematical Center, and by Poznan University of Technology.
The proceedings of PODE09 will be published as a special issue of FASCICULI
MATHEMATICI.

(Project) Approximate Resolution of Geometric Optimization Problems

Project approved from "Acções Integradas Luso-Espanholas, 2009-2010"
coordinated by Belen Palop (Universidad de Valladolid) and António Leslie
Bajuelos (Universidade de Aveiro).

CEOC obteve "Very Good" na avaliação de 2007

Os resultados das várias UI&D portuguesas encontram-se aqui:
http://www.fct.mctes.pt/unidades/08/default.asp?p=1

Foi realizada uma reunião do Conselho do CEOC no dia 17/Dezembro/2008, após
a recepção da avaliação da unidade.

6th Iberian Workshop on Computational Geometry

The 6th IWCG intends to bring together, in an informal setting, researchers and students working in geometric computation. Its purpose is learning from each other of recent evolution on problems of common interest, leaving sufficient time for discussion and posing of new problems.
January 28-30,2009, Universidade de Aveiro, Portugal more details...

Arquivo

ceoc

Centre for Research on Optimization and Control
http://ceoc.mat.ua.pt