A study on parallel versus sequential relational fuzzy clustering methods

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

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.

Earthquakes and robustness for timber structures

Workshop of COST Actions TU0601 and E55 September 21-22 2009, Ljubljana, Slovenia

Synthesis about a collaborative project on “Technology Assessment of Autonomous System

The project started in 2009 with the support of DAAD in Germany and CRUP in Portugal under the “Collaborative German-Portuguese University Actions” programme. One central goal is the further development of a theory of technology assessment applied to robotics and autonomous systems in general that reflects in its methodology the changing conditions of knowledge production in modern societies and the emergence of new robotic technologies and of associated disruptive changes. Relevant topics here are handling broadened future horizons and new clusters of science and technology (medicine, engineering, interfaces, industrial automation, micro-devices, security and safety), as well as new governance structures in policy decision making concerning research and development (R

A framework for robustness assessment in the context of corroded RC structures

Structural robustness is an emergent concept related to the structural response to damage. At the present time, robustness is not well defined and much controversy still remains around this subject. Even if robustness has seen growing interest as a consequence of catastrophic consequences due to extreme events, the fact is that the concept can also be very useful when considered on more probable exposure scenarios such as deterioration, among others. This paper intends to be a contribution to the definition of structural robustness, especially in the analysis of reinforced concrete structures subjected to corrosion. To achieve this, first of all, several proposed robustness definitions and indicators and misunderstood concepts will be analyzed and compared. From this point and regarding a concept that could be applied to most type of structures and dam-age scenarios, a robustness definition is proposed. To illustrate the proposed concept, an example of corroded reinforced concrete structures will be analyzed using nonlinear analysis numerical methods based on a contin-uum strong discontinuities approach and isotropic damage models for concrete. Finally the robustness of the presented example will be assessed.

Protein glycosylation of exosomes from ovarian carcinoma cells: structures and biological roles

Dissertation presented to obtain the Ph.D. degree in Biology

Robustness of corroded reinforced concrete structures

Short Term Scienti c Mission, COST ACTION TU-0601

Um middleware para computação paralela em clusters de multicores

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

In situ measured cross section geometry of old timber structures and its influence on structural safety

Old timber structures may show significant variation in the cross section geometry along the same element, as a result of both construction methods and deterioration. As consequence, the definition of the geometric parameters in situ may be both time consuming and costly. This work presents the results of inspections carried out in different timber structures. Based on the obtained results, different simplified geometric models are proposed in order to efficiently model the geometry variations found. Probabilistic modelling techniques are also used to define safety parameters of existing timber structures, when subjected to dead and live loads, namely self-weight and wind actions. The parameters of the models have been defined as probabilistic variables, and safety of a selected case study was assessed using the Monte Carlo simulation technique. Assuming a target reliability index, a model was defined for both the residual cross section and the time dependent deterioration evolution. As a consequence, it was possible to compute probabilities of failure and reliability indices, as well as, time evolution deterioration curves for this structure. The results obtained provide a proposal for definition of the cross section geometric parameters of existing timber structures with different levels of decay, using a simplified probabilistic geometry model and considering a remaining capacity factor for the decayed areas. This model can be used for assessing the safety of the structure at present and for predicting future performance.

Ligand K-edge X-ray absorption spectroscopy and DFT calculations on [Fe3S4]0,+ clusters: delocalization, redox, and effect of the protein environment

Ligand K-edge XAS of an [Fe3S4]0 model complex is reported. The pre-edge can be resolved into contributions from the í2Ssulfide, í3Ssulfide, and Sthiolate ligands. The average ligand-metal bond covalencies obtained from these pre-edges are further distributed between Fe3+ and Fe2.5+ components using DFT calculations. The bridging ligand covalency in the [Fe2S2]+ subsite of the [Fe3S4]0 cluster is found to be significantly lower than its value in a reduced [Fe2S2] cluster (38% vs 61%, respectively). This lowered bridging ligand covalency reduces the superexchange coupling parameter J relative to its value in a reduced [Fe2S2]+ site (-146 cm-1 vs -360 cm-1, respectively). This decrease in J, along with estimates of the double exchange parameter B and vibronic coupling parameter ì2/k-, leads to an S ) 2 delocalized ground state in the [Fe3S4]0 cluster. The S K-edge XAS of the protein ferredoxin II (Fd II) from the D. gigas active site shows a decrease in covalency compared to the model complex, in the same oxidation state, which correlates with the number of H-bonding interactions to specific sulfur ligands present in the active site. The changes in ligand-metal bond covalencies upon redox compared with DFT calculations indicate that the redox reaction involves a two-electron change (one-electron ionization plus a spin change of a second electron) with significant electronic relaxation. The presence of the redox inactive Fe3+ center is found to decrease the barrier of the redox process in the [Fe3S4] cluster due to its strong antiferromagnetic coupling with the redox active Fe2S2 subsite.

Implementation for spatial data of the shared nearest neighbour with metric data structures

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Building clusters for CRM strategies by mining airlines customer data

Trabalho de Projeto apresentado como requisito parcial para obtenção do grau de Mestre em Estatística e Gestão de Informação

Incidência do cancro do estômago e do pulmão : um estudo espacio-temporal na região sul de Portugal Continental entre 2000-2008

RESUMO - Enquadramento/Objectivos: As doenças oncológicas constituem a segunda causa de morte em Portugal, e têm um profundo impacto psicossocial, não só pela sua elevada incidência e mortalidade mas também pelos enormes custos envolvidos na sua prevenção, tratamento e reabilitação. De acordo com estudos anteriores, existem disparidades geográficas na incidência da doença oncológica. É por isso indispensável caracterizar e analisar as diferentes distribuições espaciais no tempo e no espaço, para controlar a doença e promover a saúde, contribuindo ao mesmo tempo para uma melhor compreensão da etiologia da doença. Este projecto compreende 3 objectivos principais que são: a caracterização de distribuição espacio-temporal do cancro do pulmão e do cancro do estômago, separadamente e em conjunto, na região sul de Portugal Continental (abrangida pelo ROR-Sul) no espaço temporal de 2000 a 2008, procurando identificar potenciais áreas de risco no desenvolvimento destes tumores. Metodologia: Numa primeira fase realizou-se um estudo descritivo das taxas de incidência dos tumores aqui retratados por idades, por sexo, por ano e por distritos. Posteriormente com o objectivo de identificar a presença de áreas de elevada incidência, procedeu-se à análise de clustering espacio-temporal das taxas de incidência ao nível dos concelhos na região do estudo, em 2000-2008. Resultados: Os resultados da análise descritiva revelaram que ambos os tumores são mais incidentes nos homens do que nas mulheres e que estes são igualmente mais incidentes em pessoas com mais de 75 anos. A análise de clustering espacio temporal permitiu verificar a existência um padrão geográfico heterogéneo da incidência de ambos os tumores, da qual resultaram 3 clusters para o cancro do estômago e 2 clusters para o cancro do pulmão (p <0,001). Os clusters do estômago pertencem maioritariamente à região do Alentejo e os clusters do cancro do pulmão à região da grande Lisboa. Conclusões: Os resultados da análise de clustering demonstraram um padrão heterogéneo da distribuição da incidência dos dois cancros na região e período temporal do estudo. As zonas identificadas de elevado risco são diferentes para ambos o tumores. A região que apresenta maior risco para o desenvolvimento do cancro do estômago é o Alentejo e do pulmão é o distrito de Lisboa.

Cortisol e testosterona no plasma da grávida e no líquido amniótico: variação com o relaxamento e correlação com o rácio digital 2D:4D no recém-nascido

RESUMO: Conclusão - Este estudo sugere que mulheres grávidas beneficiam da prática rotineira de 30 min de relaxamento perante a eminência de um acontecimento indutor de stress. O benefício será tanto psicológico como fisiológico e será mais marcado de manhã do que de tarde. As mulheres com maior tendência ansiosa, tipicamente as mais jovens e com menos idade gestacional, serão as que mais beneficiam. Entre os tipos de intervenção experimentados, todos eles não dispendiosos, a audição de música foi globalmente o mais eficaz para o propósito pretendido. A variação do cortisol e a variação da testosterona estão altamente correlacionadas, e este efeito poderá ser explorado em futuras intervenções relaxantes. Programas curtos de relaxamento poderão conduzir a benefícios para o bem-estar psicológico e para a saúde da grávida, com benefícios adicionais no desfecho da gravidez. O rácio digital 2D:4D do recém-nascido apresenta características sexualmente dimórficas, sendo mais baixo em rapazes que em raparigas, confirmando a influência dos androgénios pré-natais, mas há grande sobreposição entre os sexos pelo que, isoladamente, não pode ser utilizado como marcador de risco. No entanto, se associado a outros marcadores biológicos, como o peso ao nascer e a circunferência cerebral, entre outros, poderá ser um parâmetro a valorizar desde cedo, possivelmente no acompanhamento pediátrico. Nas raparigas, o RD da mãe e a testosterona no LA explicam uma proporção significativa do seu 2D:4D. Em ambos os sexos, o rácio 2D:4D aumenta após o nascimento e o dimorfismo sexual observado com base em amostras de crianças com mais de dois anos de idade, é afectado pela testosterona pós-natal, especialmente no que se refere à mão direita.----------ABSTRACT: Conclusions - This study suggests that pregnant women would benefit from the routine practice of 30min relaxation when at the imminence of a stressful event. The benefit would be both psychological and physiological and would be more pronounced in the morning than in the afternoon. Women tending to be more anxious, typically younger and at a lower gestational age, are the ones that benefit the most. Among the interventions investigated, all being non-expensive and easy to implement, listening to relaxing music was globally the most efficient for the benefit intended. The variation of cortisol and the variation of testosterone are significantly correlated, an association that might be used in future relaxation interventions. It is feasible to conceive short relaxation programs aimed at benefiting psychological well-being and health in pregnancy, with additional benefits for pregnancy outcome. The digital ratio 2D:4D is sexually dimorphic, being lower in males than in females, confirming the influence of pre-natal androgens. There is however large overlap between sexes, rendering the 2D:4D a risk marker not to be used in isolation but rather in association with other markers, like for instance the weight at birth and the head circumference, wherein it may be a relevant parameter for pediatric follow-up. In newborn females, a significant amount of variability in 2D:4D is accounted for by their mother’s digital ratio and AF testosterone. In both sexes, the 2D:4D ratio increases following birth and sexual dimorphism,as assessed from samples of subjects with more than 2 years of age, is affected by post-natal testosterone, especially in what concerns the right hand.

An application of reliability-based robustness assessment of steel moment resisting frame structures under post-mainshock cascading events

The paper presented herein proposes a reliability-based framework for quantifying the structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of 3-, 9-, and 20- stories, which were designed to pre-Northridge codes and standards. Twodimensional nonlinear finite element models of the buildings are developed using the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite-length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability-based robustness indicator used shows that the structural robustness is influenced by the extent by which a structure can distribute damage.