Desenvolvimento de um simulador de uma máquina florestal em realidade virtual

Computer-aided design (CAD) software is used in the product design and development to design complex and detailed prototypes. It provides good assistance and solid data generation to designers and engineers. In order to remain competitive, industry is always seeking for higher process efficiency and product quality enhancement in the shortest period of time. Continuous research keeps going to make it possible. Virtual reality has been one of the research focus in the recent years. It is studied and applied to be used as an assistant tool in the product lifecyle management, particularly in facilitating the development phase. However, the implementation process from CAD to virtual reality remains a challenge due to time consumption and technology complexibility. In this work a real-time virtual reality harvester simulator was developed. The start point was a 3D harvester CAD model. It was used the CAD simulator AGX Momentum, a game engine Unity and the physics engine AGX Dynamics to create dynamics simulation, to design a virtual forest environment and to enable physical controllers interact with the model. With the capabilities of AGX Momentum, it was added dynamics motion directly in the CAD software, creating fast CAD simulations. A virtual scene was designed with Unity to simulate an environment and the immersion of the user on it with Oculus Rift device. The harvester model was imported to the Unity scene with AGX Dynamics. In the end it was obtained a real size virtual prototype, with the possibility of interacting and control it using physical controllers. The user can visualise the scene in real-time through a head mounted display, providing him the experience of a real machine operator. Driving the harvester in a simulated forest, allowed to test the model in a hypothetical real scenario. The process of implementing the CAD model in virtual reality used in this work, revealed to be efficient and intuitive. However, because it is a complex and large model, it was necessary to remove certain bodies (without dynamics effect) and reduce the number of contact points between components in order to balance the speed and performance of the simulator. Following the same method used in this work, Other CAD models can be imported to virtual reality and be dynamically simulated.Software de desenho assistido por computador – do inglês, computer aided design (CAD) é usado no processo de desenvolvimento e design de produto para projetar protótipos complexos e detalhados. Este tipo de software fornece boa assistência e gera consistentes dados de modelos para designers e engenheiros. Com vista a manter-se competitiva, a indústria está sempre à procura de uma maior eficiência do processo e de uma melhoria da qualidade do produto a desenvolver no menor perı́odo de tempo possı́vel. A investigacão, nos últimos anos e em curso, tem tentado tornar isto possı́vel. A realidade virtual tem sido um dos focos dessa investigação. Tem sido estudada e aplicada para ser usada como ferramenta auxiliar na gestão do ciclo de vida do produto, em particular na facilitação da fase de desenvolvimento. Contudo, o processo de implementação do CAD em realidade virtual continua a ser um desafio devido quer à complexidade tecnológica envolvida, quer ao tempo requerido. Neste trabalho foi desenvolvido um simulador de tempo real a partir de uma máquina florestal harvester em realidade virtual. O ponto de partida consistiu num modelo CAD da máquina. Para isso, foi utilizado o simulador CAD AGX Momentum, o motor de jogo Unity e o motor de fı́sica AGX Dynamics para adicionar dinâmica ao modelo, criar um ambiente virtual de uma floresta e permitir que controladores fı́sicos interagissem com o protótipo. Com os recursos de AGX Momentum, foi adicionado movimento dinâmico diretamente no software CAD, criando rápidas simulações. Através do Unity, foi projetado um cenário virtual para simular um ambiente virtual e promover a imersão do utilizador com o dispositivo Oculus Rift. O modelo da harvester foi, depois, importado para a “cena” com AGX Dynamics. No final, foi obtido um protótipo virtual em tamanho real, com a possibilidade de interagir e ser controlado usando comandos fı́sicos. O utilizador pode visualizar a cena em tempo real através de um dispositivo de realidade virtual, proporcionando-lhe a experiência de um real operador da máquina. Ao conduzir a harvester numa floresta virtual, permitiu testar o modelo num cenário hipoteticamente real. O processo de implementação do modelo CAD em realidade virtual utilizado neste trabalho revelou-se eficiente e intuitivo. No entanto, por se tratar de um modelo complexo e extenso, foi necessário remover determinados sólidos (sem interferência dinâmica) e reduzir o número de pontos de contacto entre componentes para equilibrar a velocidade e desempenho do simulador. Seguindo o mesmo método utilizado neste trabalho, outros modelos CAD podem ser importados para a realidade virtual e ser dinamicamente simulados.Mestrado em Engenharia Mecânic

Private equity challenge: Vidrala as a potential Lbo target

The goal of this thesis is to assess Vidrala as a potential leveraged buyout target. Market and company overviews were performedto evaluate the company ́s positioning and financial performance, as well as future trends within the glass packaging industry, the respective end-markets and other packaging solutions. This analysis was used to select the most suitable investment strategies and quantify the resulting business plan in financial terms. Finally, a valuation using several methods was conducted from which a capital structured was designed and potential returns calculated. This part will cover returns, exit strategies and risks and due diligence

Antibiotics and extracorporeal circulation - one size does not fit all

Dosing of antibiotics in critically ill patients is a significant challenge. The increasing number of patients undergoing extracorporeal membrane oxygenation further complicates the issue due to inflammatory activation and to drug sequestration in the circuit. Since patients receiving extracorporeal membrane oxygenation commonly face severe infections, appropriate antibiotic selection and correct dosing is of paramount importance to improve survival. Therapeutic drug monitoring (whenever available) or population pharmacokinetics, based on readily available clinical and laboratory data, should help tailor antibiotic dosing to the individual patient.publishersversionpublishe

How strong is this 'strong' evidence?

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Rede neuronal artificial para o reconhecimento de caracteres com interface gráfica

Os propósitos deste trabalho são meramente académicos e visam a experimentação das Redes Neuronais Artificiais numa situação típica de reconhecimento de caracteres. Adicionalmente foi experimentada a utilização concomitante do LabVIEW e do Matlab, tirando partido da interface gráfica do LabVIEW e da facilidade de utilização das RNA no Matlab. Os caracteres reconhecidos são os números de 0 a 9 e as letras maiúsculas de A a Z. Cada símbolo é codificado numa matriz booleana de 5×5. Como existem 36 caracteres no total, resulta uma matriz de 25×36 (dados de entrada da rede). Para a correspondência de cada vector de entrada, é usada uma matriz de saída de 36×36 que toma valores ‘0’ ou ‘1’. Para a RNA foi adoptada uma tipologia feedforward com duas camadas escondidas, funções de activação tansig, e trainrp como função de treino [1]. Para o treino da rede recorreu-se à Neural Network Toolbox™ do Matlab®, e ao LabVIEW™ para o desenvolvimento da interface gráfica. Deste modo, resultou um ambiente gráfico muito amigável e de grande utilidade, devido à troca de dados entre estes dois ambientes de programação. A rede apresenta uma boa tolerância a falhas e bom desempenho

A methodological approach to evaluate elderly-robot interactions

The relevance in the study of interaction between elderly and robots may depend on the choice of activities that robots can be developed to perform and the assessment of their impact and importance for older people. This research requires coordinated research between computer engineers and specialists in the humanities and social sciences. Being a recent research area, it is particularly relevant to carefully select the behavioural variables to be analyzed, the methodology adopted and the instruments that allow for a rigorous evaluation. Based on these assumptions, the present study aims to develop Innovative Initiatives for the Promotion of Active Aging in the EUROACE Region. The authors propose an appropriate methodology and instruments to evaluate the impact of the human-robot interaction in the promotion of a more active aging in a group of elderly in a nursing home. The analyzed variables focus on the involvement of the elderly in the activities, their capacity for initiative and to establish social interactions, indicators of well-being and a proactive attitude. The methodology of the study is mixed (qualitative and quantitative), organized as an exploratory case study. Data collection is based on naturalistic observation but variables are quantitatively assessed in a pre/post-test design. The research design identified the narratives of the elderly and the staff of the institution regarding the needs and interests of each elderly person, classified the participants according to the levels of prevailing social interactions, involvement and initiative in activities, considered important variables for an active ageing and, in this sense, demonstrated its adequacy to be used to evaluate the results of the intervention using social assistive robots.info:eu-repo/semantics/publishedVersio

Identificação de caracteres com rede neuronal artificial com interface gráfica

O presente artigo aborda uma metodologia para efectuar o reconhecimento de caracteres utilizando redes neuronais artificiais, com recurso da Toolbox Neural Network do Matlab®. Cada caractere é desenhado numa matriz 5x5, em que os pontos escuros do caractere tomam o valor de ´1´ e os pontos claros equivalem a ´0´. Posteriormente, esta matriz é reorganizada numa única coluna, de modo que cada coluna da matriz de input para a função de treino da rede represente um único caractere. As colunas da matriz de output determinam os caracteres correspondentes às colunas da matriz de input, com uma representação de um ‘1’ para o caractere desejado e ’0’ nos outros casos. Foi desenvolvida uma interface gráfica utilizando o GUIDE (Graphical User Interface Development Environment) do Matlab®. Deste modo, é possível escolher os parâmetros para criar a rede neuronal, treiná-la e proceder à sua simulação, de uma forma interactiva e agradável

User-hosted SOA infrastructure over XMPP

The principles of Service-Oriented Architecture (SOA) argue for the design of systems composed of re-usable coarse-grained software components which consume and provide services in a service ecosystem. Despite being commonly mentioned in an enterprise context, these are very present in the web - most web applications expose some of their data via APIs, which are then used by other web and mobile applications. The proliferation of user-owned connected devices has brought value to mobile application developers which can make use of locally-available sensors and capabilities and send their information to the web, centralizing the data flows. A more distributed approach would have device capabilities offered directly on the network as services hosted by the user. These pervasive user-hosted services could be made discoverable and available over a public federated service infrastructure. The infrastructure would provide transport over an identity layer, where endpoints are addressed by their identities instead of network identifiers, and on top of which services can be exposed to be consumed by trusted friends or anonymous users, as the hosting user prefers. The work presented in this paper explores the possibility of implementing a distributed social SOA over Extensible Messaging and Presence Protocol (XMPP). It differs from traditional SOA because it attempts to counter relative centralization of the web, in favour of a fully-distributed service ecosystem where each peer can behave both as service consumer and provider. Finally, an analysis is done on how suitable XMPP is to serve as a base protocol for such infrastructure

Quality of Work Life and Contribution to Productivity: Assessing the Moderator Effects of Burnout Syndrome

This study is focused on assessing the effects of burnout as a moderator of the relationship between employees’ quality of work life (QWL) and their perceptions of their contribution to the organization’s productivity by integrating the QWL factors into the trichotomy of (de)motivators of productivity in the workplace. The empirical findings resulting from an OLS multiple regression, with interaction terms, applied to a survey administered at 514 employees in 6 European countries, point out two important insights: (i) QWL hygiene factors (e.g., safe work environment and occupational healthcare) positively and significantly influence the contribution to productivity; and (ii) burnout de-motivator factors (that is, low effectiveness, cynicism, and emotional exhaustion) significantly moderate the relationship between QWL and the contribution to productivity. Combining burnout with other QWL components, such as occupational health, safe work, and appropriate salary, new insights are provided concerning the restricting (i.e., low effectiveness and cynicism) and catalyzing (emotional exhaustion) burnout components of contribution to productivity. These findings are particularly relevant given the increased weight of burnout, mental disorders and absenteeism in the labor market, affecting individuals’ quality of life and organizations’ performance and costs.info:eu-repo/semantics/publishedVersio