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.
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)
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)
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)
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
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:
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.
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
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.
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.
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).
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
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...
January 28-30,2009, Universidade de Aveiro, Portugal more details...
Lecture at foreigner university: Scattering by obstacles
Evgeny Lakshtanov will give an invited lecture in Mathematics Institut in
Munique.
http://www.mathematik.uni-muenchen.de/~lerdos/os0809/
Munique.
http://www.mathematik.uni-muenchen.de/~lerdos/os0809/
Recent publications and communications from Tatiana Tchemisova (CEOC Member)
Publications:
1) Kostyukova O.I., Tchemisova T.V, Yermalinskaya S.A.
{\it On One Optimality Criterion for the Problem of Convex Semi-Infinite
Programming}, proceedings of International Scientific Conference "X
Belarusian Mathematical Conference", Minsk, Belarus, 3-7 of November 2008,
pp.
101-102 (proceedings with referee).
2)Ozogur-Akyuz S., Akteke-Ozturk B., Tchemisova T., and Weber G.-W., {\it
New Optimization Methods in Data Mining}, proceedings of International
Conference "Operations Research 2008", Augsburg, Germany, September 3-5,
2008,(Accepted for proceedings with referee).
3)Kostyukova O.I., Tchemisova T.V., {\it Sufficient Optimality Conditions
for Convex Semi-Infinite Programming}, accepted to publication in Special
Issue of "Optimization Methods and Software", 2008.
4) Tchemisova T.V., Yermalinskaya S.A., {\it Algorithm of Determination of
the Orders of Immobile Indices and Implicit Optimality Criterion for the
Problems of Convex Semi-Infinite Programming}, proceedings of the
International Conference "Dynamic Systems: Stability, Control,
Optimization", devoted to 90-th anniversary of academician E.A.Barbashin,
p.165-166, Minsk, Belarus, 29
September-4 October, 2008 (proceedings with referee), pp.165-166.
1) Kostyukova O.I., Tchemisova T.V, Yermalinskaya S.A.
{\it On One Optimality Criterion for the Problem of Convex Semi-Infinite
Programming}, proceedings of International Scientific Conference "X
Belarusian Mathematical Conference", Minsk, Belarus, 3-7 of November 2008,
pp.
101-102 (proceedings with referee).
2)Ozogur-Akyuz S., Akteke-Ozturk B., Tchemisova T., and Weber G.-W., {\it
New Optimization Methods in Data Mining}, proceedings of International
Conference "Operations Research 2008", Augsburg, Germany, September 3-5,
2008,(Accepted for proceedings with referee).
3)Kostyukova O.I., Tchemisova T.V., {\it Sufficient Optimality Conditions
for Convex Semi-Infinite Programming}, accepted to publication in Special
Issue of "Optimization Methods and Software", 2008.
4) Tchemisova T.V., Yermalinskaya S.A., {\it Algorithm of Determination of
the Orders of Immobile Indices and Implicit Optimality Criterion for the
Problems of Convex Semi-Infinite Programming}, proceedings of the
International Conference "Dynamic Systems: Stability, Control,
Optimization", devoted to 90-th anniversary of academician E.A.Barbashin,
p.165-166, Minsk, Belarus, 29
September-4 October, 2008 (proceedings with referee), pp.165-166.
Communications:
1)Kostyukova O.I., Tchemisova T.V, Yermalinskaya S.A. {\it On One Optimality
Criterion for the Problem of Convex Semi-Infinite Programming},
International Scientific Conference "X Belarusian Mathematical Conference",
Minsk, Belarus, 3-7 of November 2008.
(regular seminar) Necessary optimality conditions and implicit function
Orador: ARAM ARUTYUNOV, Peoples Friendship University of Russia, Moscow.
Resumo: The talk consists of two parts. The first part is devoted to the abstract minimization problem with constraints, which is called the mathematical programming problem. In the second part we discuss local properties of smooth nonlinear mappings in a neighborhood of an abnormal point. The problems that are studied in this talk (of course, in addition to their extremal nature) are united by the fact that we are mainly interested in studying the so-called abnormal or nonlinearized problems.
Resumo: The talk consists of two parts. The first part is devoted to the abstract minimization problem with constraints, which is called the mathematical programming problem. In the second part we discuss local properties of smooth nonlinear mappings in a neighborhood of an abnormal point. The problems that are studied in this talk (of course, in addition to their extremal nature) are united by the fact that we are mainly interested in studying the so-called abnormal or nonlinearized problems.
Computer Application available from the Maple Application Centre
Title: Computing ODE symmetries as abnormal variational symmetries.
Authors: Paulo D. F. Gouveia and Delfim F. M. Torres
Application Type: Maple Worksheet Publish date: November, 2008
URL:
http://www.maplesoft.com/applications/app_center_view.aspx?AID=2326&CID=1&SC
ID=94
Authors: Paulo D. F. Gouveia and Delfim F. M. Torres
Application Type: Maple Worksheet Publish date: November, 2008
URL:
http://www.maplesoft.com/applications/app_center_view.aspx?AID=2326&CID=1&SC
ID=94
(local seminar) Rotas Seguras usando a 2-cobertura
Inês Pereira deMatos, Estudante de Doutoramento, Universidade de Aveiro.
Resumo: Dados n discos de raio r no plano, que representam
antenas, radares, sensores ou outros equipamentos de
vigilância com alcance limitado. Um ponto no plano está
2-coberto se estiver coberto por pelo menos dois destes discos.
Na sequência da importância prática desta classe de
problemas e dos resultados obtidos para minimizar o alcance
dos equipamentos de vigilância para 2-cobrir um ponto, apresentaremos
alguns resultados relacionados com o cálculo do
alcance mínimo para a 2-cobertura de um segmento de recta,
uma linha poligonal, um polígono arbitrário e um conjunto
de pontos no plano. Como último caso, analisaremos como
encontrar a melhor rota segura (2-coberta) entre duas localizações
(vértices) num grafo não dirigido, grafo esse que
representa um mapeamento de estradas.
21 de Novembro de 2008 (Departamento de Matemática, sala Sousa Pinto,
11:00-12:00)
Resumo: Dados n discos de raio r no plano, que representam
antenas, radares, sensores ou outros equipamentos de
vigilância com alcance limitado. Um ponto no plano está
2-coberto se estiver coberto por pelo menos dois destes discos.
Na sequência da importância prática desta classe de
problemas e dos resultados obtidos para minimizar o alcance
dos equipamentos de vigilância para 2-cobrir um ponto, apresentaremos
alguns resultados relacionados com o cálculo do
alcance mínimo para a 2-cobertura de um segmento de recta,
uma linha poligonal, um polígono arbitrário e um conjunto
de pontos no plano. Como último caso, analisaremos como
encontrar a melhor rota segura (2-coberta) entre duas localizações
(vértices) num grafo não dirigido, grafo esse que
representa um mapeamento de estradas.
21 de Novembro de 2008 (Departamento de Matemática, sala Sousa Pinto,
11:00-12:00)
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Centre for Research on Optimization and Control
http://ceoc.mat.ua.pt