Exploração inteligente de objetos por manipulador robótico

The end goal of this dissertation is to develop an autonomous exploration robot that is capable of choosing the Next Best View which reveals the most amount of information about a given volume. The exploration solution is based on a robotic manipulator, a RGB-D sensor and ROS. The manipulator provides movement while the sensor evaluates the scene in its Field of View. Using an OcTree implementation to reconstruct the environment, the portions of the de ned exploration volume where no information has been gathered yet are segmented. This segmentation (or clustering) will help on the pose sampling operation in the sense that all generated poses are plausible. Ray casting is performed, either based on the sensor's resolution or the characteristics of the unknown scene, to assess the pose quality. The pose that is estimated to provide the evaluation of the highest amount of unknown space is the one chosen to be visited next, i.e., the Next Best View. The exploration reaches its end when all the unknown voxels have been evaluated or, those who were not, are not possible to be measured by any reachable pose. Two case studies are presented to test the performance and adaptability of this work. The developed system is able to explore a given scene which, initially, it has no information about. The solution provided is, not only, adaptable to changes in the environment during the exploration, but also, portable to other manipualtors rather than the one used in the development.O objetivo nal desta dissertação é desenvolver um robot de exploração autônomo capaz de escolher a Próxima Melhor Vista que revela a maior quantidade de informações sobre um determinado volume. A solução de exploração é baseada num manipulador robótico, num sensor RGB-D e em ROS. O manipulador proporciona movimento enquanto o sensor avalia a cena no seu campo de visão. Usando uma implementação Oc- Tree para reconstruir o ambiente, as partes do volume de exploração de nido onde nenhuma informação ainda foi recolhida são segmentadas. Esta segmenta ção (ou agrupamento) ajudará na operação de amostragem de poses no sentido em que todas as poses geradas são plausíveis. Ray casting é realizado, seja com base na resolução do sensor ou nas características da cena desconhecida, para avaliar a qualidade da pose. A pose que é estimado fornecer a avaliação da maior quantidade de espaço desconhecido é a escolhida para ser visitada em seguida, ou seja, a Próxima Melhor Vista. A exploração chega ao m quando todos os voxels desconhecidos tiverem sido avaliados ou, aqueles que não o foram, não sejam possíveis de serem medidos por qualquer pose alcançável. Dois casos de estudo são apresentados para testar o desempenho e adaptabilidade deste trabalho. O sistema desenvolvido é capaz de explorar uma determinada cena sobre a qual, inicialmente, não tem informação. A solução apresentada é, não só, adaptável às mudanças no ambiente durante a explora ção, mas também, portável para outros manipuladores que não o utilizado no desenvolvimento.Mestrado em Engenharia Mecânic

Youth Unemployment Determinants and Interactions with Inequality

Youth unemployment rates are significantly and consistently higher than total unemployment rates, hitting particularly high values in a crisis context. The aim of this work is to assess the determinants of youth unemployment in developed countries, relying on a youth to total unemployment ratio, and investigate its impact on income inequality. Using data from 18 OECD countries from 1990 to 2019, the results of the estimations indicate a widening effect of labor market flexibilization and economic growth on the gap between youth and total unemployment rates, with a narrowing effect from postsecondary educational attainment. Moreover, this work shows no evidence of a significant impact of youth unemployment on income inequality.As taxas de desemprego jovem são significativa e consistentemente mais elevadas em comparação com as taxas de desemprego totais, atingindo valores particularmente altos em contexto de crise. O objetivo deste trabalho é aferir os determinantes do desemprego jovem em países desenvolvidos, recorrendo ao rácio entre as taxas de desemprego jovem e total, e investigar o seu impacto na desigualdade de rendimentos. Utilizando dados de 18 países da OCDE entre 1990 e 2019, os resultados das estimações demonstram que a flexibilização dos mercados de trabalho e o crescimento económico ampliam a disparidade entre as taxas de desemprego jovem e total, enquanto o nível educacional pós-secundário a reduz. Adicionalmente, este trabalho não demonstra evidências de que exista um impacto significativo do desemprego jovem na desigualdade de rendimentos

Encounter management

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 200

Práticas de Responsabilidade Social Corporativa nos municípios do distrito de Setúbal: exemplo de quatro municípios

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Ciências Empresariais – Ramo Gestão de PMEO debate sobre a “Responsabilidade Social Corporativa” estendeu-se nos últimos anos para outros setores de atividade, para além do setor privado, alargando-se para o setor público. Com essa evolução, surgiram novas questões face à “Responsabilidade Social Corporativa”, sendo que essas questões debatam-se em primeiro lugar se existem diferenças no conceito de “Responsabilidade Social Corporativa” dentro do setor privado e público e em segundo lugar, quais as práticas que poderão ser consideradas no setor público. Deste modo, a presente dissertação pretende analisar quais as práticas de “Responsabilidade Social Corporativa” aplicadas em municípios do distrito de Setúbal, com o objetivo de perceber se existem diferenças na Responsabilidade Social entre o setor público e privado. A metodologia utilizada nesta investigação foi o estudo de caso, através da realização de inquéritos e entrevistas semiestruturadas em quatro municípios do distrito de Setúbal. Esta opção deve-se à necessidade de estudar a temática de forma aprofundada e como um todo.Abstract: In recent years the debate around "Corporate Social Responsibility" has spread from the private sector the public sector. While it was mainly a concept applied in the private sector, it has shifted to the public sector as well. With that, new questions have arisen. First of all, one has to wonder if there are differences in "Corporate Social Responsibility" within the private and public sectors. Secondly, which practices may be considered in the public sector. Therefore, this thesis’ aim is to analyze the practices applied in Setúbal district's municipalities. Furthermore, we expect to understand whether there are differences in "Corporate social responsibility" between the public and private sector. The methodology used in this research was the case study. This methodology was applied through the realization of questionnaires and semi structured interviews in four municipalities from Setúbal's district. This option is due to the need to study the issue in depth and as a whole

Análise de fiabilidade de sistemas e componentes de helicópteros

Este trabalho ocorre face à necessidade da empresa Helisuporte ter uma perspectiva a nível de fiabilidade das suas aeronaves. Para isso, foram traçados como objectivos de estudo a criação de uma base de dados de anomalias; identificação de sistemas e componentes problemáticos; caracterização dos mesmos, avaliar a condição de falha e, com isto, apresentar soluções de controlo de anomalias. Assim, foi desenvolvida uma metodologia que proporciona tratamento de dados com recurso a uma análise não-paramétrica, tendo sido escolhida a estatística de amostra. Esta irá permitir a identificação dos sistemas problemáticos e seus componentes anómalos. Efectuado o tratamento de dados, passamos para a caracterização fiabilística desses componentes, assumindo o tempo de operação e a vida útil específica de cada um. Esta foi possível recorrendo ao cálculo do nível de fiabilidade, MTBF, MTBUR e taxa de avarias. De modo a identificar as diferentes anomalias e caracterizar o “know-how” da equipa de manutenção, implementou-se a análise de condição de falha, mais propriamente a análise dos modos e efeitos de falha. Tendo isso em atenção, foi construído um encadeamento lógico simples, claro e eficaz, face a uma frota complexa. Implementada essa metodologia e analisados os resultados podemos afirmar que os objectivos foram alcançados, concluindo-se que os valores de fiabilidade que caracterizam alguns dos componentes das aeronaves pertencentes à frota em estudo não correspondem ao esperado e idealizado como referência de desempenho dos mesmos. Assim, foram sugeridas alterações no manual de manutenção de forma a melhorar estes índices. Com isto conseguiu-se desenvolver, o que se poderá chamar de, “fiabilidade na óptica do utilizador”.This research is due to the need of the company Helisuporte have a perspective on the reliability of their aircraft. For that were created as objectives of study the creation of data base, identification of Systems and components with anomalies associated, reliability characterization for the same items, failure mode’s evaluation and solution’s presentation. The methodology used as the sample’s statistic as a method for data processing. This is a noparametrical analysis. It will identify the systems and components with failures. Than we characterize the components with reliability elements, which were reliability, MTBF, MTBUR and failure rate. Were assumed mission time and operation life of witch component. To characterize the anomalies and evaluate the maintenance crew’s “know-how” was implanted a failure mode’s analysis using the failure mode and effect analysis (FMEA). With that in mind, we built a simple logical sequence, clear and efficient, compared to a complex fleet. With the implementation of this ideology and analyzed the results, we conclude that the reliability values that characterize some of the components of aircraft within the fleet under study, do not correspond to the expected and designed as a reference for their performance. As a solution for this were suggested improvements in the maintenance manual of this aircraft. With this, we had developed what one might call ”reliability in a user’s perspective

Osteotomy at low-speed drilling without irrigation versus high-speed drilling with irrigation: an experimental study

"Introduction: Excessively traumatic surgery can adversely affect the maturation of bone tissue and consequently diminish the predictability of osseointegration so the mechanical and thermal damage should be minimized during surgical procedure. The purpose of this study is to evaluate immediate histological alterations in rabbit tibias, produced by low speed drilling (50 rpm) without irrigation and conventional drilling (800 rpm) under profuse irrigation. Material and Methods: Thirty-six implant osteotomies were created in the tibias of 6 White female rabbits. Drilling began with a 1.5 mm round bur, followed by 2.0 mm, 2.5 mm and 3.5 mm helical drills. The posterior tibial cortex was evaluated as the positive control, and it was preserved during the surgical procedure. The receptor beds were collected for histological analysis. Results: All defects showed regular edges. Hematoxylin eosin (HE) sections showed that both techniques preserved the bone structure and the presence of living cells. No histological differences between the two surgical drilling techniques were found. Conclusions: Based on our results, we can conclude that the effects of implant site preparation on bone by low speed drilling (50 rpm) without irrigation and conventional drilling (800 rpm) under abundant irrigation are similar. Both surgical drilling techniques preserve bone-cell viability and the clinician can decide which drilling technique to use, based on other criteria. Keywords: Osteotomy; Osseointegration; Rabbits; Therapeutic Irrigation; Tibia; Wound Healing.

MONITORIA ACADÊMICA EM ZOOLOGIA DOS INVERTEBRADOS: UM RELATO DE EXPERIÊNCIA

In the discipline of zoology of invertebrates, it is up to the monitor, in the practical part, to perform its functions of assisting, mediating, socializing, teaching and researching. The article aims to report the experiences experienced in the academic monitoring of zoology of invertebrates, reporting, mainly, on the methodologies developed. Thus, to facilitate the understanding of the contents of zoology, a practical class was made available after the theoretical study of each phylum of the animal kingdom. Most of these practices were developed in the multidisciplinary laboratory of the university and in this article, five of them were described, related to the following contents: Protozoa. Porifera, Mollusca and Arthropoda. Students enrolled in the zoology disciplines of invertebrates I and II participated in the classes, these students showed interest, curiosity and attention during the moments of visualization under the microscope, revision, dissection and mount of the arthropod collection. Therefore, it is concluded that monitoring contributes both to the academic training of monitors and to a better progress of the discipline, favoring the development of applied methodologies.En la disciplina de zoología de los invertebrados, corresponde al monitor, en la parte práctica, desempeñar sus funciones de auxiliar, mediación, socialización, enseñanza e investigación. El artículo tiene como objetivo informar experiencias experimentadas en el seguimiento académico de la zoología de los invertebrados, principalmente sobre las metodologías desarrolladas. En este sentido, se puso a disposición una clase práctica después del estudio teórico de cada filo del reino animal. La mayoría de estas prácticas se desarrollaron en el laboratorio multidisciplinario de la universidad y en este artículo, cinco de ellos fueron descritos, relacionados con los siguientes contenidos: Protozoa. Porifera, Mollusca y Arthropoda. Los estudiantes matriculados en las disciplinas de zoología de los invertebrados I y II participaron en las clases, estos mostraron interés, curiosidad y atención durante los momentos de visualización bajo el microscopio, revisión, disección y montaje de la colección de artrópodos. Por lo tanto, se concluye que el monitoreo contribuye tanto a la formación académica de los monitores como a un mejor progreso de la disciplina, favoreciendo el desarrollo de las metodologías aplicadas.Na disciplina de zoologia dos invertebrados, compete ao monitor, na parte prática, exercer suas funções de auxiliar, mediar, socializar, lecionar e pesquisar. O artigo objetiva relatar experiências vivenciadas na monitoria acadêmica de zoologia dos invertebrados, discorrendo, principalmente, acerca das metodologias desenvolvidas. Nesse sentido, foi disponibilizada uma aula prática após o estudo teórico de cada filo do reino animal. A maioria dessas práticas foram desenvolvidas no laboratório multidisciplinar da universidade e neste artigo foram descritas cinco delas, relacionadas com os seguintes conteúdos: Protozoa, Porifera, Mollusca e Arthropoda. Participaram das aulas os alunos matriculados nas disciplinas de zoologia dos invertebrados I e II. Estes mostraram interesse, curiosidade e atenção durante os momentos de visualização no microscópio, revisão, dissecação e montagem da coleção dos artrópodes. Portanto, conclui-se que a monitoria contribui tanto para a formação acadêmica dos monitores quanto para um melhor andamento da disciplina, favorecendo o desenvolvimento das metodologias aplicadas

Effects of industrial noise on circumpulpar dentin - a field emission scanning electron microscopy and energy dispersive spectroscopy analysis

"Chronic exposure to Industrial Noise (IN), rich in Low Frequency Noise (LFN), causes systemic fibrotic transformation and sustained stress. Dental wear, significantly increased with exposure to LFN, affects the teeth particularly through the circumpulpar dentin. Our goal is to understand the consequences of IN exposure on the circumpulpar dentin of Wistar rats. 10 Wistar rats were exposed to IN for 4 months, according to an occupationally simulated time schedule and 10 animals were used as age-matched controls. The first and the second upper and lower molars of each animal were processed for observation by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDS) analysis was performed. In exposed animals FESEM showed a 2.0 to 6.0 μm-dense mineral band between dentin and the pulp with no regular continuity with the tubules. This structure had a few tubules where the odontoblasts processes could be observed embedded within the band and collagen fibers were trapped inside. EDS analysis revealed that it was hydroxyapatite similar to dentin, with a higher carbon content. FESEM results show that the band may be tertiary reparative dentin formed by odontoblast-like cells, but the increased amount of carbon (EDS) could mean that it is sclerotic dentin. IN should be acknowledge as a strong stimulus, able to cause an injury to odontoblasts and to the formation of reparative tertiary dentin, in a process that may accelerate the aging of the teeth, either by direct impact of acoustic pressure pulsations or by increased stress and dental wear.

Effects of large pressure amplitude low frequency noise in the parotid gland perivasculo-ductal connective tissue

"Introduction: In tissues and organs exposed to large pressure amplitude low frequency noise fibrosis occurs in the absence of inflammatory signs, which is thought to be a protective response. In the parotid gland the perivasculo-ductal connective tissue surrounds arteries, veins and the ductal tree. Perivasculo-ductal connective tissue is believed to function as a mechanical stabilizer of the glandular tissue. Material and Methods: In order to quantify the proliferation of perivasculo-ductal connective tissue in large pressure amplitude low frequency noise-exposed rats we used sixty Wistar rats which were equally divided into 6 groups. One group kept in silence, and the remaining five exposed to continuous large pressure amplitude low frequency noise: g1-168h (1 week); g2-504h (3 weeks); g3-840h (5 weeks); g4-1512h (9 weeks); and g5-2184h (13 weeks). After exposure, parotid glands were removed and the perivasculo-ductal connective tissue area was measured in all groups. We applied ANOVA statistical analysis, using SPSS 13.0. Results: The global trend is an increase in the average perivasculo-ductal connective tissue areas, that develops linearly and significantly with large pressure amplitude low frequency noise exposure time (p < 0.001). Discussion: It has been suggested that the biological response to large pressure amplitude low frequency noise exposure is associated with the need to maintain structural integrity. The structural reinforcement would be achieved by increased perivasculo-ductal connective tissue. Conclusions: Hence, these results show that in response to large pressure amplitude low frequency noise exposure, rat parotid glands increase their perivasculo-ductal connective tissue.