A calculus for modeling and analyzing conversations in service-oriented computing

Dissertação apresentada para a obtenção do Grau de Doutor em Informática pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Strengthening to seismic action of reinforced columns with rectangular cross-section

The first part of this research work regards the assessment of the mathematical modelling of reinforced concrete columns confined with carbon fibre (CFRP) sheets under axial loading. The purpose was to evaluate existing analytical models, contribute to possible improvements and choose the best model(s) to be part of a new model for the prediction of the behaviour of confined columns under bending and compression. For circular columns, a wide group of authors have proposed several models specific for FRP-confined concrete. The analysis of some of the existing models was carried out by comparing these with several tested columns. Although several models predict fairly the peak load only few can properly estimate the load-strain and dilation behaviour of the columns. Square columns confined with CFRP show a more complex interpretation of their behaviour. Accordingly, the analysis of two experimental programs was carried out to propose new modelling equations for the whole behaviour of columns. The modelling results show that the analytical curves are in general agreement with the presented experimental curves for a wide range of dimensions. An analysis similar to the one done for circular columns was this turn carried out for square columns. Few models can fairly estimate the whole behaviour of the columns and with less accuracy at all levels when compared with circular columns. The second part of this study includes seven experimental tests carried out on reinforced concrete rectangular columns with rounded corners, different damage condition and with confinement and longitudinal strengthening systems. It was concluded that the use of CFRP confinement is viable and of effective performance enhancement alone and combined with other techniques, maintaining a good ductile behaviour for established threshold displacements. As regards the use of external longitudinal strengthening combined with CFRP confinement, this system is effective for the performance enhancement and viable in terms of execution. The load capacity was increased significantly, preserving also in this case a good ductile behaviour for threshold displacements. As to the numerical nonlinear modelling of the tested columns, the results show a variation of the peak load of 1% to 10% compared with tests results. The good results are partly due to the inclusion of the concrete constitutive model by Mander et al. modified by Faustino, Chastre & Paula taking into account the confinement effect. Despite the reasonable approximation to tests results, the modelling results showed higher unloading, which leads to an overestimate dissipated energy and residualdisplacement.

Cognitive models for the concept of angle

Tese de doutoramento em Filosofia

Comments on ‘‘Modeling fractional stochastic systems as non-random fractional dynamics driven Brownian motions

Applied Mathematical Modelling, Vol.33

A new least-squares approach to differintegration modeling

Signal Processing, Vol. 86, nº 10

Tertiary evolution of the São Vicente and Setúbal submarine canyons, Southwest Portugal: insights from seismic stratigraphy

The Setúbal and São Vicente canyons are two major modern submarine canyons located in the southwest Iberian margin of Portugal. Although recognised as Pliocene to Quaternary features, their development during the Tertiary has not been fully understood up to date. A grid of 2D seismic data has been used to characterise the sedimentary deposits of the adjacent flanks to the submarine canyons. The relationship between the geological structure of the margin and the canyon's present location has been investigated. The interpretation of the main seismic units allowed the recognition of three generations of ravinements probably originated after middle Oligocene. Six units grouped in two distinctive seismic sequences have been identified and correlated with offshore stratigraphic data. Seismic Sequence 2 (SS2), the oldest, overlies Mesozoic and upper Eocene deformed units. Seismic Sequence I (SS1) is composed of four different seismic packages separated from SS2 by an erosional surface. The base of the studied sediment ridges is marked by an extensive erosional surface derived from a early/middle Oligocene relative sea-level fall. Deposition in the adjacent area to the actual canyons was reinitiated in late Oligocene in the form of transgressive and channel-fill deposits. A new depositional hiatus is recorded onshore during the Burdigalian, coincident with the unconformity separating SS1 and SS2. This can be correlated with the Arrábida unconformity and with the paroxysmal Burdigalian phase of the Betic domain. Presently, the Setúbal and São Vicente submarine canyons locally cut SS1 and SS2, forming distinctive channels from those recognised on the seismic data. On the upper shelf both dissect highly deformed areas subject to important erosion.

Vibration control with shape-memory alloys in civil engineering structures

Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Doutor em Engenharia Civil

Improving discovery in the life sciences using semantic Web technologies and linked data: design principles for life sciences knowledge organization systems

Dissertation presented to obtain the Ph.D degree in Bioinformatics

Robustness of timber structures in seismic areas

Some of the properties sought in seismic design of buildings are also considered fundamental to guarantee structural robustness. Moreover, some key concepts are common to both seismic and robustness design. In fact, both analyses consider events with a very small probability of occurrence, and consequently, a significant level of damage is admissible. As very rare events,in both cases, the actions are extremely hard to quantify. The acceptance of limited damage requires a system based analysis of structures, rather than an element by element methodology, as employed for other load cases. As for robustness analysis, in seismic design the main objective is to guarantee that the structure survives an earthquake, without extensive damage. In the case of seismic design, this is achieved by guaranteeing the dissipation of energy through plastic hinges distributed in the structure. For this to be possible, some key properties must be assured, in particular ductility and redundancy. The same properties could be fundamental in robustness design, as a structure can only sustain significant damage if capable of distributing stresses to parts of the structure unaffected by the triggering event. Timber is often used for primary load‐bearing elements in single storey long‐span structures for public buildings and arenas, where severe consequences can be expected if one or more of the primary load bearing elements fail. The structural system used for these structures consists of main frames, secondary elements and bracing elements. The main frame, composed by columns and beams, can be seen as key elements in the system and should be designed with high safety against failure and under strict quality control. The main frames may sometimes be designed with moment resisting joints between columns and beams. Scenarios, where one or more of these key elements, fail should be considered at least for high consequence buildings. Two alternative strategies may be applied: isolation of collapsing sections and, provision of alternate load paths [1]. The first one is relatively straightforward to provide by deliberately designing the secondary structural system less strong and stiff. Alternatively, the secondary structural system and the bracing system can be design so that loss of capacity in the main frame does not lead to the collapse. A case study has been selected aiming to assess the consequences of these two different strategies, in particular, under seismic loads.

Building information modeling: oportunidades e desafios para projectistas e donos de obra em Portugal

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Civil-Perfil de Construção

Constraint-based modeling of minimum set covering: application to species differentation

Work presented in the context of the European Master in Computational Logics, as partial requisit for the graduation as Master in Computational Logics

Modeling assembly program with constraints. A contribution to WCET problem

Dissertação para obtenção do Grau de Mestre em Lógica Computacional

Accessing meteorological data in INSPIRE

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Urban sprawl analysis and modeling in Asmara, Eritreia: Application of Geospatial Tools

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Urban land cover change detection analysis and modeling spatio-temporal Growth dynamics using Remote Sensing and GIS Techniques: A case study of Dhaka, Bangladesh

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.