Seminários do CEAUL

Sala 6.2.50, FCUL, Lisboa

Extreme Value Laws and Point Processes of Rare Events for Chaotic Dynamical Systems

Ana Cristina Moreira Freitas
FEP and CMUP, Universidade do Porto

We consider discrete time dynamical systems and show the linking between Extreme Value Laws and Hitting Time Statistics. The stochastic processes arise from dynamical systems by evaluating an observable function (which achieves a global maximum at a single point of the phase space) along the orbits of the system. We exploit the connection between these two approaches both in the absence and presence of clustering. We associate the existence of an Extremal Index less than 1 to the occurrence of periodic phenomena. We show that, under certain conditions, in the absence of clustering, the point processes of exceedances converge to a standard Poisson process. In the presence of clustering, the point processes converge to a compound Poisson process, so instead of single exceedances, we have entire clusters of exceedances occurring at Poisson times with a geometric distribution ruling its multiplicity. We will also consider observables achieving a global maximum at multiple points which are correlated by belonging to the same orbit of a certain chosen point. We will see that this is a mechanism capable of creating clustering without an underlying periodic phenomenon and with different types of patterns.

Complete Convergence of Rare Events Point Processes and Records with Clustering

Jorge Milhazes de Freitas
FCUP and CMUP, Universidade do Porto

We consider time series corresponding to the evaluation of given potential along the orbits of systems with `nice' first return induced maps. Nice, here, means good memory loss properties. We are particularly interested in events corresponding to exceedances of high thresholds, i.e. instants at which the potential reaches abnormally high values, and, more specifically, when these exceedances have a tendency to appear in clusters. This clustering effect is known to be related to some form of underlying periodicity and we study its effects in the convergence of conveniently normalised point processes that count the number of exceedances in a certain time frame. We consider bidimensional point processes marking the exceedance instants in the x-axis and their severity in the y-axis. The convergence of these bidimensional processes is then used to obtain information about records.

CEAUL - Centro de Estatística e Aplicações da Universidade de Lisboa

This meeting is part of a series of successful field symposiums that started in the early 2000’s. The meeting in Lisbon and the Algarve (3-7 September 2017) will follow this tradition and will provide an opportunity for fruitful scientific discussions.&nbs

The aim of the EMAPI 2017 is to promote the opportunity to share findings and experiences - research, management, and policy - with professionals from around the world.

This meeting aims to develop interactions between mathematicians working in Functional Analysis, Group Representation Theory, Matrix Theory and Linear Systems, and other relevant areas. Participation is open to anyone with interests in these and other related areas.

Optimization 2017 is the ninth edition of a series of Optimization international conferences held every three or four years, in Portugal.

Submissão de propostas a decorrer até 07 de setembro de 2017 (12:00 CET).

Ana Raquel Duque Gonçalves Fernandes apresenta a dissertação "Identificação de padrões alimentares na dieta de doentes com degenerescência macular relacionada com a idade".

Estudar e analisar os pavimentos de uma cidade tão antiga quanto Lisboa permite-nos conhecer a história e evolução da cidade de Lisboa ao longo dos tempos.

O encontro, a decorrer de 20 a 22 de setembro de 2017, tem como tópicos principais o desenvolvimento de técnicas instrumentais avançadas, a proteómica, a metabolómica, a análise de pequenas moléculas, e a espectrometria de massa estrutural e nativa.

Candidaturas a Bolsas de Doutoramento a decorrer até 02 de outubro de 2017.

Programa de Formação Contínua de Professores do Ensino Básico (3.º ciclo) e Secundário, grupos 420 e 520.

Adaptationism, i.e. the claim that natural selection provides a sufficient explanation for the evolution of most traits, pervades all aspects of biological thinking.

The European Symposium on Nanofluids (ESNf) will be a series of international conferences to be organized in Europe and the very first one (1st ESNf) will be held in Lisbon, Portugal during 8-10 October 2017.

A iniciativa conta com a participação de Henrique Leitão (FCUL), decorrendo as expressões de interesse até 12 de maio de 2017.

For understanding Nature, modern science has turned to mathematical and physical models that dramatically simplified the complexity of natural phenomena and processes.

There are thousands of totally sequenced genomes freely available in the Internet. The number keeps on growing as at least one genome sequence is released every day.

The objective of the symposium is to present new approaches to deal with Big Data Applications in finance, retail and commerce bringing together professionals from companies in these areas and researchers who generate sound methods and tools to handle such data.

ECCA 2017 will be a unique meeting place where the people driving climate adaptation on the ground, from business, civil society and national and local governments, can share ideas and experience with the world’s leading researchers and policymakers.

Natural history museums are privileged spaces for seminal research on different subjects of biological sciences such as biodiversity, evolution, ecology, biogeography and taxonomy.

A diversidade biológica, em todas as suas formas e níveis de organização, garante importantes serviços ecológicos dos quais, em última instância, depende o bem-estar humano.

Objectives: To introduce participants to the details of communicating science to non-specialized audiences, including, but not exclusive to, public and private stakeholders, students and teachers, and media professionals.

Evolutionary theory provides a framework for understanding all living systems. Nevertheless, throughout the 20th century, with a few exceptions, evolutionary biologists have “avoided” using evolution to address problems related to our own species.

Under the general framework of Global Change Ecology, the goal of this course is to provide the participants with the most recent and practical knowledge on the use of Functional Diversity.

During recent decades we have witnessed a great development of bioinformatics that has led to the accumulation of a huge amount of biological information.

The objective of this course is to introduce participants to the details of communication and writing scientific publications. The main emphasis is on the most common form, the “primary scientific paper”, but other forms will be covered.

Phylogenetics is one of the scientific areas of Biology that has grown fast and evolved in methodological terms in the last years.