Structured Linearization of Discrete Mechanical Systems for Analysis and Optimal Control

Variational integrators are well-suited for simulation of mechanical systems because they preserve mechanical quantities about a system such as momentum, or its change if external forcing is involved, and holonomic constraints. While they are not energy-preserving they do exhibit long-time stable energy behavior. However, variational integrators often simulate mechanical system dynamics by solving an implicit difference equation at each time step, one that is moreover expressed purely in terms of configurations at different time steps. This paper formulates the first- and second-order linearizations of a variational integrator in a manner that is amenable to control analysis and synthesis, creating a bridge between existing analysis and optimal control tools for discrete dynamic systems and variational integrators for mechanical systems in generalized coordinates with forcing and holonomic constraints. The forced pendulum is used to illustrate the technique. A second example solves the discrete LQR problem to find a locally stabilizing controller for a 40 DOF system with 6 constraints.Comment: 13 page

Os Jesuítas no Espírito Santo 1549-1759: contactos confrontos e encontros

Este trabalho analisa a acção missionária jesuíta na capitania do Espírito Santo entre 1549 e 1759no quadro geral do Brasil colónia dentro do estruturado espaço colonial português, comummente chamado Império. O objectivo principal deste trabalho é o levantamento de dados sobre a sua actuação no processo geopolítico religioso na capitania onde se cruzam colonizadores, indígenas de diferentes etnias, estrangeiros e religiosos. Do encontro dos dogmas cristãos com o pensamento indígena e a intenção dos colonizadores surge o confronto. Os jesuítas elaboram então um conjunto de propostas que contribuíram para a evolução do pensamento político moderno e mudaram as regras dentro da própria Companhia. Destacam-se as missões indígenas e as fazendas, como polos de surgimento duma nova cultura que resulta do cruzamento dos diferentes agentes envolvidos e o seu papel na permuta e consolidação da presença portuguesa: ABSTRACT: Jesuits in Espírito Santo 1549-1759: contacts, confrontations and encounters This work analyzes Jesuit missionary activities in the Captaincy of Espírito Santo (1549-1759) in colonial Brazil (1500-1822) within the framework of the Portuguese colonial Empire (1415-1974). This work is based on data found on the religious geo-political process in the Captaincy of Espírito Santo whereby European colonizers, indigenous people from different ethnic groups, foreigners, and members of many religious groups lived and interacted with one another, at times peacefully, at times not-so-peacefully. Eventually the Catholic dogmas of the Europeans clashed against native beliefs; hence, conflicts with the European colonizers arose. In order to protect the native population from "European" cultural and physical aggressions, the Jesuits elaborated a complex system that eventually opened the doors to modern thought, thus changing the rules of their own organization, i.e., the Society of Jesus. Special attention is paid to the Jesuit missions to the native population and to the fazendas (plantation-type farms) since both functioned as platforms of a new culture: the coming together of different people and their role in negotiating and consolidating Portuguese presence in colonial Brazil

Who is the one I find different from me?

Comunicação apresentada no Congresso internacional "Inclusive and Supportive Education", na Universidade de Strathclyde (Glasgow), em Agosto de 2005.Difference and Diversity are concepts upon which inclusive school development should be rooted. However, when one talks about difference, the meaning attributed to that concept assumes a great spectrum of possible explanations, certainly based on individual experience and one’s framework of analysis, expressed through a particular world view. The main goal of this research project is to understand how school children and youngsters conceive difference, in other words, what kind of characteristics are stressed when they describe someone they find much different from them and what kind of relationships they think possible to establish with that person. The population was chosen among children and youngsters of all the public schools of Beja (Portugal), constituting three age groups of 9, 12 and 15 years old. In this research we used the written narrative as a method of analysis. What is proposed in this paper is to discuss some of the preliminary results and reflect upon some questions raised, which may bring a different perspective on inclusive education

Integrating Ecohydraulics in River Restoration: Advances in Science and Applications

Rivers have been intensively degraded due to increasing anthropogenic impacts from a growing population in a continuously developing world. Accordingly, most rivers suffer from pressures as a result of increasing dam and weir construction, habitat degradation, flow regulation, water pollution/abstraction, and the spread of invasive species. Science-based knowledge regarding solutions to counteract the effects of river degradation, and melding principles of aquatic ecology and engineering hydraulics, is thus urgently needed to guide present and future river restoration actions. This Special Issue gathers a coherent set of studies from different geographic contexts, on fundamental and applied research regarding the integration of ecohydraulics in river restoration, ranging from field studies to laboratory experiments that can be applied to real-world challenges. It contains 13 original papers covering ecohydraulic issues such as river restoration technologies, sustainable hydropower, fish passage designs and operational criteria, and habitat modeling. All papers were reviewed by international experts in ecology, hydraulics, aquatic biology, engineering, geomorphology, and hydrology. The papers herein well represent the wide applicability of ecohydraulics in river restoration and serve as a basis to improve current knowledge and management and to reduce arguments between different interests and opinions

Trends in employment and HRM practices: the influence of new technologies

Trabalho apresentado no 3rd ISA Forum of Sociology, 10-14 de julho de 2016, Vienna, AustriaN/

The social side of fertility in Portugal and Spain: evidence from the European Social Survey (Round 2)

info:eu-repo/semantics/publishedVersio

Returning to active life after aphasia rehabilitation

Aphasia is an acquired language disability caused by brain damage, usually stroke, that affects the person’s ability to communicate with others since it may compromise speaking, understanding, reading, and writing. Aphasia affects the biopsychosocial integrity of the individuals compromising their social relationships (SR), their participation in activities, their emotional status and their QOL. Usually people with aphasia have difficulties in returning to previous activities and roles, specially returning to work.info:eu-repo/semantics/publishedVersio

Is the decrease of fertility a consequence of the postponement of the Entrance in the labour market?

As the postponement in the age of entrance into the labour market and the fertility decline in Portugal are a primary concern in Society it is important to understand the patterns associated with this issue. Data from the Portuguese Labour Force Survey (LFS) - data source: National Statistical Institute - from 1998 to 2004 was utilised in order to study the evolution of the entrance age into the labour market and the relationships between entrance age, sex and education level. The multinomial logit model evidenced that being a woman, being younger or having a higher qualification implied a later entrance age into the labour market, while being a man, being older or having lower qualifications were involved in an earlier entrance into the labour market.info:eu-repo/semantics/publishedVersio