On the degeneracy phenomenon for nonlinear optimal control problems with higher index state constraints

Relatório Técnico do Núcleo de Investigação Officina Mathematica.Necessary conditions of optimality (NCO) play an important role in optimization problems. They are the major tool to select a set of candidates to minimizers. In optimal control theory, the NCO appear in the form of a Maximum Principle (MP). For certain optimal control problems with state constraints, it might happen that the MP are unable to provide useful information --- the set of all admissible solutions coincides with the set of candidates that satisfy the MP. When this happens, the MP is said to degenerate. In the recent years, there has been some literature on fortified forms of the MP in such way that avoid degeneracy. These fortified forms involve additional hypotheses --- Constraint Qualifications. Whenever the state constraints have higher index (i.e. their first derivative with respect to time does not depend on control), the current constraint qualifications are not adequate. So, the main purpose here is fortify the maximum principle for optimal control problems with higher index constraints, for which there is a need to develop new constraint qualifications. The results presented here are a generalization to nonlinear problems of a previous work.The financial support from Projecto FCT POSC/EEA-SRI/61831/2004 is gratefully acknowledged

Web-based access control system

This article describes a web-based system to control and manage the access to the ESTCB, which it is under development as a student’s final project. Beyond an important pedagogical and technological value, we believe that this work is an important step towards offering strong and efficient security management for access control systems. We make use of standard technologies in use on the Web, to make an effective campus-wide security system. The system management and configuration, the consultation of access information for schedules, users, spaces, among others, will be carried out through the Internet. The proposed model is based on the use of two data nets: a CAN field bus to which are connected magnetic cards readers, door locks and sensors of each access place and the Ethernet that establishes connection between different CAN field bus and servers, which contain information about users and access rules

Angiogenesis and Breast Cancer

Angiogenesis is an essential step for breast cancer progression and dissemination. The development of new blood vessels in cancer setting (angiogenesis) is conducted by numerous physiological and pathological stimuli, where the main stimulus is hypoxia. The knowledge of different molecular pathways regulating angiogenesis is constantly growing. An increased and complex scenario of angiogenesis is nowadays available in breast cancer, specifically, and permits not only to understand most of the important phases of neoplastic growth but also offer an exciting perspective for new therapeutic proposals based on blocking new blood vessels sprouting. This review focused on historical and recent understanding of angiogenesis occurrence in breast cancer

Cenozoic seismic stratigraphy and tectonic evolution of the Algarve margin (offshore Portugal, southwestern Iberian Peninsula)

The Cenozoic seismic stratigraphy and tectonic evolution of the Algarve margin (southwestern border of the Iberian Peninsula) are documented from multichannel seismic reflection data, isochron and time-structure maps.http://www.sciencedirect.com/science/article/B6V6M-4KJV3F0-1/1/141771fd1c5ee441b6f226a499be5e2

An integral-type constraint qualification for optimal control problems with state constraints

Relatório Técnico do Núcleo de Investigação Officina Mathematica.Standard necessary conditions of optimality (NCO) for constrained optimal control problems -- Maximum Principle type onditions -- may fail to provide useful information to select candidates to minimizers among the overall set of admissible solutions. This phenomenon is known as the degeneracy phenomenon and there has been continuing interest in the literature in proposing stronger forms of NCO that can be informative in such cases: the so-called nondegenerate NCO. The nondegenerate NCO proposed here are validunder a different set of hypothesis and under a constraint qualification of an integral-type that, in relation to some previous literature, can be verified for more problems.Fundação para a Ciência e a Tecnologia (FCT) Projecto FCT POSC/EEA-SRI/61831/200

On the relation between inward pointing velocity conditions

Inward pointing velocity conditions are important in the study of whether trajectories remain within sets (the so-called invariance or viability) and also to establish constraint qualifications (CQ) under which necessary conditions of optimality for control problem can be guaranteed to be nondegenerate NCO or normal. In our research on nondegenerate NCO we have studied different types of CQs in the form of inward pointing velocity (IPV) conditions, and, in particular, in which situation one type implies other type of IPV. Such findings are reported in the article.FCT Project PTDC/EEA -CRO/116014/2009 "Optimal Control in Constrained and Hybrid Nonlinear Systems

Computational micromechanics of the transverse and shear behavior of unidirectional fiber reinforced polymers including environmental effects

Qualification of Fiber Reinforced Polymer materials (FRP’s) for manufacturing of structural components in the aerospace industry is usually associated with extensive and costly experimental campaigns. The burden of testing is immense and materials should be characterized under different loading states (tension, compression, shear) and environmental conditions (temperature, humidity) to probe their structural integrity during service life. Recent developments in multiscale simulation, together with increased computational power and improvements in modeling tools, can be used to alleviate this scenario. In this work, high-fidelity simulations of the material behavior at the micro level are used to predict ply properties and ascertain the effect of ply constituents and microstructure on the homogenized ply behavior. This approach relies on the numerical analysis of representative volume elements equipped with physical models of the ply constituents. Its main feature is the ability to provide fast predictions of ply stiffness and strength properties for different environmental conditions of temperature and humidity, in agreement with the experimental results, showing the potential to reduce the time and costs required for material screening and characterization.The authors would like to acknowledge the support provided by AIRBUS SAS through the project SIMSCREEN (Simulation for Screening Composite Materials Properties). Additionally, C.S. Lopes acknowledges the support of the Spanish Ministry of Economy and Competitiveness through the Ramón y Cajal program. The help of Dr. Miguel Monclús and Dr. Jon Molina in the experimental work is also gratefully acknowledged

Interface characterization in fiber-reinforced polymer-matrix composites

A novel methodology is presented and applied to measure the shear interface strength of fiber-reinforced polymers. The strategy is based in fiber push-in tests carried out on the central fiber of highly-packed fiber clusters with hexagonal symmetry, and it is supported by a detailed finite element analysis of the push-in test to account for the influence of hygrothermal residual stresses, fiber constraint and fiber anisotropy on the interface strength. Examples of application are presented to determine the shear interface strength in carbon and glass fiber composites reinforced with either thermoset or thermoplastic matrices. In addition, the influence of the environment (either dry or wet conditions) on the interface strength in C/epoxy composites is demonstrated.This investigation was supported by the Ministerio de Ciencia e Innovación of Spain through the Grant MAT2012-37552, by the Comunidad de Madrid through the program DIMMAT (P2013/MIT2775), and by the European Community's Seventh Framework Programme FP7/2007-2013 under Grant Agreement 213371 (MAAXIMUS, www.maaximus.eu). In addition, the support of Airbus through the project SIMSCREEN ("Simulation for Screening Properties of Materials") is gratefully acknowledged

Organização de comunidades de besouros rola-bosta (Coleoptera, Scarabaeidae) em áreas de re-estabelecimento de vegetação em Feira de Santana, Bahia, Brasil

The present work refers to the study of colonization of four vegetation physiognomies considered as succession stages by Scarabaeidae beetles in Feira de Santana, Brazil. The four environments present structures of 1) herbs, 2) herbs and bushes, 3) bushes, and 4) bushes and trees. The last one has similar vegetation elements to the original vegetation of the area (Caatinga, in transition with deciduous forest). Beetles’ richness was not statistically different in the three structurally simpler habitats, the composition, as well as the abundance structure of the communities of the four sites were very similar. Guild structure changed in number and proportion of specimens, with an increase in the number of tunnelers as the vegetation grew in complexity. The positive/negatives effects on the composition and beetles’s community structure were related to the interference with the dissemination of odor plumes or maintenance of sources of resources (vertebrates). The organization of the functional structure in the beetles’ community should be related to the time needed for the establishment of complex ecological connections.O presente trabalho refere-se ao estudo de colonização de quatro fisionomias de vegetação consideradas como estágios sucessionais, em Feira de Santana, Brasil, por besouros Scarabaeidae. Os quatro ambientes possuem estruturas: 1) herbácea, 2) herbácea/arbustiva, 3) arbustivo/arbórea e 4) arbórea. Esta última com elementos de vegetação similares à vegetação original da área (Caatinga, em transição com floresta decídua). A riqueza de besouros não foi estatisticamente diferente nos três ambientes estruturalmente mais simples, e tanto a composição quanto a estrutura de abundância das comunidades dos quatro sítios foram muito semelhantes. A estrutura de guildas mudou em número e proporção de espécies, com aumento no número de “escavadores” com o aumento na complexidade estrutural da vegetação, cujos efeitos positivos / negativos sobre a composição e estrutura da comunidade de besouros foi relacionado à interferência sobre a disseminação de plumas de odor ou manutenção de fontes de recursos (vertebrados). A organização da estrutura funcional da comunidade de besouros deve ser relacionada ao tempo necessário para o estabelecimento de conexões ecológicas complexas.O presente trabalho refere-se ao estudo de colonização de quatro fisionomias de vegetação consideradas como estágios sucessionais, em Feira de Santana, Brasil, por besouros Scarabaeidae. Os quatro ambientes possuem estruturas: 1) herbácea, 2) herbácea/arbustiva, 3) arbustivo/arbórea e 4) arbórea. Esta última com elementos de vegetação similares à vegetação original da área (Caatinga, em transição com floresta decídua). A riqueza de besouros não foi estatisticamente diferente nos três ambientes estruturalmente mais simples, e tanto a composição quanto a estrutura de abundância das comunidades dos quatro sítios foram muito semelhantes. A estrutura de guildas mudou em número e proporção de espécies, com aumento no número de “escavadores” com o aumento na complexidade estrutural da vegetação, cujos efeitos positivos / negativos sobre a composição e estrutura da comunidade de besouros foi relacionado à interferência sobre a disseminação de plumas de odor ou manutenção de fontes de recursos (vertebrados). A organização da estrutura funcional da comunidade de besouros deve ser relacionada ao tempo necessário para o estabelecimento de conexões ecológicas complexas

Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment

Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucária, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin