Control a 2-Axis Servomechanism by Gesture Recognition using a Generic WebCam
- João Manuel R. S. Tavares; Ricardo Ferreira; Francisco Freitas
This paper presents two approaches used to control a 2-axis servomechanism by gesture recognition. For both approaches, the adopted control philosophy was: In the system’s learning phase, the control images are acquired by a generic webcam and associated to the desired orders. On the other hand, in the working phase, each control image is acquired, by the same webcam and, by comparison with the stored orders images, the desired order is recognized and processed by the servomechanism in quasi real time. In this paper, the used servomechanism and both implemented approaches are described, and are indicated some advantages and weakness...
Improvement of Modal Matching Image Objects in Dynamic Objects Matching Improvement using Optimization Techniques in a Geometric Modal Methodology
- Luísa F. Bastos; João Manuel R. S. Tavares
This work was based on a previously developed methodology using shape modal description for matching image objects. With this methodology, the objects points were matched using a local search approach. This paper presents a global search methodology using optimization techniques to establish the correspondences between two objects. It was also developed a solution to match excess points after the usual "one to one" matching, if the number of nodes that compose both objects is not the same. It is also briefly presented the method used for the determination of the rigid transformation between two objects, which facilitates the results analysis.
Matching Contours in Images using Curvature Information and Optimization based on Dynamic Programming
- F. P. M. Oliveira; João Manuel R. S. Tavares
This paper presents a novel methodology to match
contours of objects represented in images. In the matching, we
use sets of ordered points extracted from the external contours of
the objects. Each of these points defines a vertex of a polygon to
be associated to the correspondent contour. To establish the
matching, we compute a cost matching matrix by comparing the
amplitudes of the angles defined by the vertices of one of the
contours with the amplitudes of the angles defined by the vertices
of the other contour. Afterwards, the optimal global matching
that preserves the contours points orders is determined using an
optimization algorithm based on dynamic programming;
Drilling of carbon fibre reinforced laminates – a comparative analysis of five different drills on thrust force, roughness and delamination
- L.M.P. Durão; D.J.S. Gonçalves; J.M.R.S. Tavares; V.H.C. Albuquerque; A.T. Marques; A.M. Baptista
The distinguishing characteristics of carbon fibre reinforced laminates, like low weight, high strength or stiffness, had resulted in the increase of their use during the last decades. Although parts are normally produced to "near-net" shape, machining operations like drilling are still needed. In result of composites non-homogeneity, this operation can lead to delamination, considered the most serious kind of damage as it can reduce the load carrying capacity of the joint. A proper choice of tool and cutting parameters can reduce delamination substantially. In this work, the results obtained with five different tool geometries are compared. Conclusions show that the...
A prototype system for acquisition and analysis of 3D mandibular movement
- Isa C. T. Santos; João Manuel R. S. Tavares; Joaquim Mendes; Manuel P. F. Paulo
This paper presents the development of a new prototype system for acquisition and analysis of the 3D mandibular movement.
In Dental Medicine, the study of the mandibular movement is very important in oral rehabilitation treatments, since it allows the diagnosis of clinical pathologies in the temporomandibular joints and therefore, it helps medical doctors to select the most adequate treatment plan and its future assessment.
In this work, a facial arc commonly used in Dental Medicine, was adapted to incorporate electromagnetic sensors to measure the movement of the mandible. Thus, some parts of the arc were redesigned, in order to ensure the best...
Calibration of bi-planar radiography with a minimal-size calibration object
- Daniel C. Moura; Jorge G. Barbosa; João Manuel R. S. Tavares; Ana M. Reis
Thermal Aging Effects on the microstructure of Nb-bearing nickel based superalloy weld overlays using ultrasound techniques
- Victor Hugo C. de Albuquerque; Cleiton Carvalho Silva; Paulo G. Normando; Elineudo P. Moura; João Manuel R. S. Tavares
Secondary phases such as Laves and carbides are formed during the final stages of solidification of the nickel based superalloy Inconel 625 coatings deposited during the gas tungsten arc welding (GTAW) cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the ´´ and phases. The aim of this work was to evaluate the different phases formed during thermal aging of the as-welded material through ultrasound inspection, as well as the influence of background echo and backscattered ultrasound signals on the computational classification of the microstructures involved. The experimental conditions employed an...
La democratización de la investigación biomédica
- Silveira Gorski, Héctor Claudio
La tecnociencia biomédica debe abrir sus puertas a la democracia. Elpoder político y el derecho deben redefinir sus relaciones con la tecnocienciapara que los científicos, expertos y ejecutivos de las empresas tecnocientíficasno sigan teniendo sólo en sus manos las decisiones sobre la orientaciónde las investigaciones y las prioridades científico-tecnológicas. La políticade la ciencia y sus aplicaciones técnicas deben abrirse a la participaciónciudadana, pasar a formar parte de la opinión pública y a ser tratados comoasuntos transversales de las políticas públicas. Para ello es necesario que elprincipio democrático se instale en el seno de la tecnociencia. La libertad deinvestigación no es...
Seismic Analysis and Strengthening of Pico Island Churches
- Arêde, António; Aníbal Costa; Domingos Moreira; Nuno Neves
The proposed study addresses the development of an integrated strategy for modelling, experimental calibration, numerical analysis and seismic strengthening carried out in two churches of the Pico Island, Azores, namely the Bandeiras and the Madalena churches. Following an initial description of the observed damages resulting from the 1998 earthquake, the modelling option for the churches’ structures is outlined. Reference is made to the use of ambient vibration tests that led to the definition of the experimental vibration frequencies and mode shapes which were then compared to the numerical ones for calibration purposes. Seismic analyses were carried out using the actual...
A comparative analysis of energy dissipation and equivalent viscous damping of RC columns subjected to uniaxial and biaxial loading
- Rodrigues, Hugo; Humberto Varum; António Arêde; Aníbal Costa
The hysteretic behaviour of RC columns has been object of many experimental studies over the past years. However, the majority of these studies are focused on unidirectional loading. An experimental program was carried out where 24 columns were tested for different loading histories, under uniaxial and biaxial conditions. The experimental results are presented in this paper and are discussed in terms of global column behaviour, and particularly with regards to energy dissipation and damping capacity. The energy dissipation capacity of the columns was evaluated in terms of cumulative dissipated energy, comparing uniaxial and biaxial test results, and individual cycle dissipated...
Monitoring of a RTM Prototype using Fiber Bragg Grating Sensors
- Célia Novo; Clara Frias; José Luís Soares Esteves; Orlando Frazão; Fábio Neto
Desenvolvimento e caracterização de novos extensómetros de embeber no betão
- Helder Sousa; Carlos Félix; Joaquim Figueiras; António Torres Marques; Pedro Vieira; José Luís Soares Esteves
Seismic Analysis of a Building Block. Bulletin of Earthquake Engineering
- Nuno Neves; António Arêde; Aníbal Costa
This paper reports on the study of the seismic response of an urban building
block located in Faial, a town of the Horta Island of the Azores, Portugal. The work fits within the framework of studying strengthening schemes suitable for the reconstruction process of a town damaged by an earthquake action and includes numerical modelling of all the building blocks with calibration of material and structural parameters based on ambiente vibration tests. The study aims at understanding a number of issues that are likely to influence the global behaviour of the block and the local response of individual buildings, namely the...
Out-of-plane behaviour of existing stone masonry buildings: experimental evaluation
- Costa, Alexandre A.; António Arêde; Aníbal Costa; Carlos Sousa Oliveira
Masonry structures can be considered as the simplest type of structures concerning its assemblage but, at the same time, it is one of the most complex construction materials in terms of mechanical properties and correct behaviour assessment. In this context, the work herein presented aims at describing an experimental testing campaign recently carried out in
order to characterize the out-of-plane behaviour of traditional masonry constructions. Taking advantage of the existence of a traditional two-storey masonry building abandoned after the 1998 Azores earthquake, several in-situ testswere defined and performed with the application of quasi-static cyclic loads at the building top level in...
Retrofit of RC Hollow Piers with CFRP Sheets
- Delgado, Pedro; António Arêde; Nelson Vila Pouca; Patricio Rocha; Aníbal Costa; Raimundo Delgado
Hollow bridge piers, particularly those built before the seventies, often have insufficient shear capacity due to inadequate transverse reinforcement details. Therefore, special attention must be given to this very important aspect when reinforced concrete (RC) piers with hollow sections are analysed and retrofitted. This paper covers the experimental analysis of retrofit solutions using CFRP sheets along the piers’ entire height to prevent shear failure. Experimental cyclic tests were carried out to evaluate the shear retrofit strategy efficiency on a set of RC piers with square hollow sections. This work also covers the study of design procedures for CFRP shear retrofitting...
Multi-master Profibus DP modelling and worst case analysis-based evaluation
- Salvatore Monforte; Eduardo Tovar; Francisco Vasques
Enciclopedismo venezolano del siglo XVIII: de la cosmología filosófica al encanto de las máquinas
- Knabenschuh de Porta, Sabine
Este artículo busca evaluar las exposicionesfisicas y astronómicas que el filósofo,
teólogo y enciclopedista venezolano Fray Juan Antonio Navarrete presenta
en su Arca de Letras y Teatro Universal, redactada a partir de 1783. Se evidencia,
junto con el abandono de los temas pertenecientes a la cosmología escolástica y de
la polémica propiamente filosófica entre escotistas y tomistas, un especial interés
por los avances tecnológicos derivados de la Nueva Ciencia. Con ello se muestra
que, terminando el siglo XVIII, la superación del escolasticismo ha encontrado finalmente
su oportunidad de libre expresión y desenvolvimiento entre los intelectuales
de la Venezuela colonial.
Strengthening and Reinforcement of Concrete Beams by the Application of CFRP Using the Filament Winding Method
- Pedro Vieira; Nuno Loureiro; José Luís Soares Esteves; António Torres Marques
Mechanical Characterisation of Natural Reinforced Plastics
- Pedro Vieira; Cristina Romão; António Torres Marques; José Luís Soares Esteves
A formação tecnológica nos cursos de Ciências da Informação e da Documentação em Portugal : Ronaldo Ferreira de Araújo, Armando Malheiro da Silva, Marlene Oliveira
- Araújo, Ronaldo Ferreira de; Silva, Armando Barreiros Malheiro da; Oliveira, Marlene
Discusses the science of information in Portugal with a focus on technology training in this area. Presents the preliminary results of a survey that aims to draw the landscape of information technology and communication while content training in information science in this country. For both analyzes the technological component in the teaching field from seven courses from undergraduate programs in information science and documentation of Portugal. From the document analysis characterizes the technological bases of the courses through the menus, objectives and program content of the disciplines of technology and also analyzes the teaching methods and evaluation procedures employed. The...