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2014
Bergel, A., R. M. R. Cardoso, A. D. Egídio dos Reis, and E. V. Rodríguez-Martínez. "The Cramér-Lundberg and the dual risk models: Ruin, dividend problems and duality features." ICA 2014, the 30th International Congress of Actuaries. Washington, D.C. 2014.
Costa, Pedro, Maria Isabel Gomes, Ana Carvalho, and Ana P. Barbosa-Povoa Decision Support Tool for Strategic Planning in Supply Chains. Proceedings of the 24th European Symposium on Computer Aided Process Engineering – ESCAPE 24. Budapest, Hungary, 2014. Abstract2014_costagomescarvalhobpovoa_escape24.pdf

This paper proposes a systematic methodology for supply chain planning optimization and assessment of different scenarios. This methodology will help companies throughout the difficult process of strategic decision-making in what concerns the design of an efficient supply chain structure. The proposed methodology allows the analysis of complex systems as it integrates a decision support tool developed to agile the process of scenario comparison, when designing network structures. This tool allows practitioners to take advantage of the optimization models without the need of learning modelling languages. An example based on a real case study is presented, showing the methodology/tool applicability.

Biscaia, Hugo C., Rui Micaelo, João Teixeira, and Carlos Chastre. "Delamination process analysis of frp-to-parent material bonded joints with and without anchorage systems using the distinct element method." Composite Structures (2014). AbstractWebsite

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Biscaia, Hugo C., Rui Micaelo, João Teixeira, and Carlos Chastre. "Delamination process analysis of FRP-to-parent material bonded joints with and without anchorage systems using the Distinct Element Method." Composite Structures. 116.September–October (2014): 104-119. AbstractWebsite

This study looks at the analysis of the interface between Fiber Reinforced Polymer (FRP)-to-parent material bonded interfaces. The performance of FRP-to-parent material bonded joints for the Externally Bonded Reinforcement (EBR) technique is numerically modelled with the PFC2D software which is based on the Distinct Element Method (DEM). It is believed that this represents the first time the DEM has been used to simulate the delamination process of FRP-to-parent material bonded joints. In order to validate the analysis performed with the DEM, a Pull-out test with no slip constrains was modelled and different linear bond-slip laws were assumed. The numerical results revealed that the DEM is capable of estimating with good accuracy the exact solutions of bond stresses, strains or slippages along the bonded length for linear bond-slip laws. The bi-linear law available in PFC2D was then compared to the numerical results obtained from other another code developed by the author. The delamination process of Pull-out tests with slip constrain at one of the free ends of the FRP plate is also described and analyzed. The results obtained from the DEM revealed that the delamination process ends with stiffness equal to the axial stiffness of the FRP plate. This evidence highlights the need to design mechanical anchor devices capable of preventing premature debonding which is known to occur on EBR systems.

Marcelo, Filipa, Fayna Garcia-Martin, Takahiko Matsushita, João Sardinha, Helena Coelho, Anneloes Oude-Vrielink, Christiane Koller, Sabine André, Eurico J. Cabrita, Hans-Joachim Gabius, Shin-Ichiro Nishimura, Jesús Jiménez-Barbero, and Javier F. Cañada. "Delineating binding modes of Gal/GalNAc and structural elements of the molecular recognition of tumor-associated mucin glycopeptides by the human macrophage galactose-type lectin." Chem. Eur. J.. in press (2014). Abstract

The human macrophage galactose-type lectin (hMGL) is a key physiological receptor for the carcinoma-associated Tn antigen (GalNAc-α-1-O-Ser/Thr) in mucins. We herein report NMR- and modeling-based data on the molecular recognition features of synthetic Tn-bearing glycopeptides by hMGL. Cognate epitopes on the sugar and matching key amino acids involved in the interaction have been identified by saturation transfer difference (STD) NMR spectroscopy. Only the amino acids close to the glycosylation site in the peptides are involved in lectin contact. Moreover, control experiments with non-glycosylated MUC1 peptides unequivocally showed that the sugar residue is essential for hMGL binding, as is Ca2+. The dissociation constants (Kd) have been estimated by STD titrations and/or STD competition experiments and show that Gal was a poor binder for hMGL, with a Kd in the mM range, while GalNAc and MUC1 Tn-glycopetides reached Kd values in the lower μM range. STD-based results suggested a distinct interacting epitope for the two monosaccharides. NMR data have been complemented with molecular dynamics simulations and Corcema- ST to establish a 3D view on the molecular recognition process between Gal, GalNAc and the Tn-presenting glycopeptides and hMGL. Gal and GalNAc have a dual binding mode with opposite trend of the main interaction pattern and the differences in affinity can be explained by additional hydrogen bonds and CH-π contacts involving exclusively the NHAc moiety.

Delgado, João, Tiago Cardoso, and Pedro Mota. "Depth Based Hand Shape Recognition using Contour Analisys." VideoJogos'2014. 2014. Abstract

— Human-Computer Interaction (HCI) faces a great challenges in what concerns the creation of a fully natural interface that is able to recognize a wide range of hand gestures in real-time. Lately efforts have been made by the research community catalyzed by the wide appearance of depth sensors such as the one from the Microsoft Kinect sensor. Nevertheless the available solutions struggle to robustly recognize hand gestures since, compared with the rest of the body, the hand is a small region with many joints, difficult to recognize and ultimately track. This paper proposes a hand shape recognition method that takes advantage of the depth sensor and the joint tracking ability of Microsoft Kinect sensor. The proposed method relies on the analysis of the hand contour or outline and compares it with previously stored templates achieving a good recognition ratio and proving it eligible
for real-time scenarios.

Faustino, Pedro, Carlos Chastre, and Raquel Paula. "Design model for square RC columns under compression confined with CFRP." Composites Part B: Engineering. 57.February (2014): 187-198. Abstractfaustino_chastre_et_al._2014.pdfWebsite

The enhancement of the mechanical behaviour of reinforced concrete (RC) columns with regard to axial compression is an up-to-date concern, namely if the strengthening of existing structures is to be considered. In view of this, external confinement with FRP systems has been tested in order to become a feasible technique, since it seems to have important advantages over other systems such as its high strength and stiffness in relation to weight and its improvement of strength and ductility while confining RC columns. Square columns confined with FRP show a more complex interpretation of their behaviour, when compared to circular columns. Accordingly, the present work includes the analysis of two experimental programs regarding axial compression on CFRP confined RC columns: one on circular and square specimens with different corner radii; the other on square specimens with side lengths ranging from medium to large. Based on this, modelling equations are proposed to predict maximum axial load, axial strain and lateral strain, as well as the entire behaviour until failure with curves of axial load-axial strain and axial load-lateral strain. The modelling results show that the analytical curves are in general agreement with the presented experimental curves for a wide range of dimensions.

Carção, Tiago, Marco Couto, Jácome Cunha, João Paulo Fernandes, and João Saraiva. "Detecting Anomalous Energy Consumption in Android Applications." Proceedings of the 18th Brazilian Symposium on Programming Languages. SBLP '14. 2014. 77-91. Abstractsblp14.pdf

The use of powerful mobile devices, like smartphones, tablets and laptops, are changing the way programmers develop software. While in the past the primary goal to optimize software was the run time optimization, nowadays there is a growing awareness of the need to reduce energy consumption. This paper presents a technique and a tool to detect anomalous energy consumption in Android applications, and to relate it directly with the source code of the application. We propose a dynamically calibrated model for energy consumption for the Android ecosystem, and that supports different devices. The model is then used as an API to monitor the application execution: first, we instrument the application source code so that we can relate energy consumption to the application source code; second, we use a statistical approach, based on fault-localization techniques, to localize abnormal energy consumption in the source code.

Rosas, João, Gonçalo Carvalho, Yves Rybarczyk, and Tiago Cardoso. "Development of an Ambient Assisted Living." Enterface 2013 Proceedings. Springer, 2014.
Cardoso, R. M. R. "Dividends in finite time horizon." Applied Stochastic Models in Business and Industry. 30.2 (2014): 172-182.
Coelho, Carlos A., and Filipe J. Marques A double decomposition of the test of independence of sets of variables that allows for a modeling view of this test. Proceedings of the 16th International Conference on Mathematical Methods, Computational Techniques and Intelligent Systems (MAMECTIS '14). Mathematics and Computers in Science and Engineering Series, 2014. Abstract

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Rybarczyk, Y., Coelho, T., Cardoso, T., and De Oliveira R. "Effect of avatars and viewpoints on performance in virtual world: efficiency vs. telepresence." EAI Endorsed Transactions on Creative Technologies. 14.1 (2014): e4.Website
Rybarczyk, Y., T. Coelho, T. Cardoso, and R. De Oliveira. "Effect of avatars and viewpoints on performance in virtual world: efficiency vs. telepresence." EAI Endorsed Transactions on Creative Technologies. 14.1 (2014): e4. Abstract

An increasing number of our interactions are mediated through e-technologies. In order to enhance the human’s feeling of presence into these virtual environments, also known as telepresence, the individual is usually embodied into an avatar. The natural adaptation capabilities, underlain by the plasticity of the body schema, of the human being make a body ownership of the avatar possible, in which the user feels more like his/her virtual alter ego than himself/herself. However, this phenomenon only occurs under specific conditions. Two experiments are designed to study the human’s feeling and performance according to a scale of natural relationship between the participant and the avatar. In both experiments, the human-avatar interaction is carried out by a Natural User Interface (NUI) and the individual’s performance is assessed through a behavioural index, based on the concept of affordances, and a questionnaire of presence The first experiment shows that the feeling of telepresence and ownership seem to be greater when the avatar’s kinematics and proportions are close to those of the user. However, the efficiency to complete the task is higher for a more mechanical and stereotypical avatar. The second experiment shows that the manipulation of the viewpoint induces a similar difference across the sessions. Results are discussed in terms of the neurobehavioral processes underlying performance in virtual worlds, which seem to be based on ownership when the virtual artefact ensures a preservation of sensorimotor contingencies, and simple geometrical mapping when the conditions become more artificial.

Soares, PI, AM Alves, LC Pereira, JT Coutinho, IM Ferreira, CM Novo, and J. P. Borges. "Effects of surfactants on the magnetic properties of iron oxide colloids." J Colloid Interface Sci.. 419 (2014): 46-51. AbstractWebsite

Iron oxide nanoparticles are having been extensively investigated for several biomedical applications such as hyperthermia and magnetic resonance imaging. However, one of the biggest problems of these nanoparticles is their aggregation.

Taking this into account, in this study the influence of three different surfactants (oleic acid, sodium citrate and Triton X-100) each one with various concentrations in the colloidal solutions stability was analyzed by using a rapid and facile method, the variation in the optical absorbance along time.

The synthesized nanoparticles through chemical precipitation showed an average size of 9 nm and a narrow size distribution. X-ray diffraction pattern and Fourier Transform Infrared analysis confirmed the presence of pure magnetite. SQUID measurements showed superparamagnetic properties with a blocking temperature around 155 K. In addition it was observed that neither sodium citrate nor Triton X-100 influences the magnetic properties of the nanoparticles. On the other hand, oleic acid in a concentration of 64 mM decreases the saturation magnetization from 67 to 45 emu/g. Oleic acid exhibits a good performance as stabilizer of the iron oxide nanoparticles in an aqueous solution for 24 h, for concentrations that lead to the formation of the double layer.

Barros, Teresa M., Krasimira T. Petrova, Paula Correia da Silva, and Ana Paula Esteves. "Efficient Microwave-Assisted Synthesis of 1’,2,3,3’,4,4’,6-Hepta-O-Benzyl-Sucrose and 1’,2,3,3’,4,4’-Hexa-O-Benzylsucrose." Carbohydrate Chemistry: Proven Synthetic Methods, Volume 2, Chapter 14. Eds. Gijsbert van der Marel, and Jeroen Codee. CRC Press, Taylor & Francis Group, 2014. 103-123.
Campos-Rebelo, Rogério, Anikó Costa, and Luís Gomes. "Elementary Events for Modeling of Human-System Interactions with Petri Net Models." Technological Innovation for Collective Awareness Systems - 5th {IFIP} {WG} 5.5/SOCOLNET Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2014, Costa de Caparica, Portugal, April 7-9, 2014. Proceedings. 2014. 219-226. Abstract

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Cunha, Jácome, João Paulo Fernandes, Jorge Mendes, Rui Pereira, and João Saraiva. "Embedding Model-Driven Spreadsheet Queries in Spreadsheet Systems." Proceedings of the 2014 IEEE Symposium on Visual Languages and Human-Centric Computing. VLHCC '14. Washington, DC, USA: IEEE Computer Society, 2014. 151-154. Abstractvlhcc14.pdf

Spreadsheets are widely used not only to define mathematical expressions, but also to store large and complex data. To query such data is usually a difficult task to perform, usually for end user. In this work we embed the textual query language in the model-driven spreadsheet environment as a spreadsheet itself. The result is an expressive and powerful query environment that has knowledge of the business logic defined by the spreadsheet data (the spreadsheet model) to guide end users constructing correct queries.

Cunha, Jácome, João P. Fernandes, Jorge Mendes, and João Saraiva. "Embedding, Evolution, and Validation of Spreadsheet Models in Spreadsheet Systems." IEEE Transactions on Software Engineering. 41.3 (2014): 241-263. Abstracttse14.pdfWebsite

This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system. This means that we enable the creation and evolution of spreadsheet models under a spreadsheet system. More precisely, we embed ClassSheets, a visual language with a syntax similar to the one offered by common spreadsheets, that was created with the aim of specifying spreadsheets. Our embedding allows models and their conforming instances to be developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.

Cunha, Jácome, João P. Fernandes, Jorge Mendes, and João Saraiva Embedding, Evolution, and Validation of Spreadsheet Models in Spreadsheet Systems. HASLab - High-Assurance Software Laboratory & Universidade do Minho, 2014. Abstracttr_embedding.pdf

This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system, so that models and their conforming instances are developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.

Silva, Micael, Angelo Miguel Figueiredo, and Eurico J. Cabrita. "Epitope mapping of imidazolium cations in ionic liquid–protein interactions unveils the balance between hydrophobicity and electrostatics towards protein destabilisation." Phys. Chem. Chem. Phys. . in press (2014). Abstract

We investigated imidazolium-based ionic liquid (IL) interactions with human serum albumin (HSA) to discern the level of cation interactions towards protein stability. STD-NMR spectroscopy was used to observe the imidazolium IL protons involved in direct binding and to identify the interactions responsible for changes in Tm as accessed by differential scanning calorimetry (DSC). Cations influence protein stability less than anions but still significantly. It was found that longer alkyl side chains of imidazolium- based ILs (more hydrophobic) are associated with a higher destabilisation effect on HSA than short-alkyl groups (less hydrophobic). The reason for such destabilisation lies on the increased surface contact area of the cation with the protein, particularly on the hydrophobic contacts promoted by the terminus of the alkyl chain. The relevance of the hydrophobic contacts is clearly demonstrated by the introduction of a polar moiety in the alkyl chain: a methoxy or alcohol group. Such structural modification reduces the degree of hydrophobic contacts with HSA explaining the lesser extent of protein destabilisation when compared to longer alkyl side chain groups: above [C2mim]+. Competition STD-NMR experiments using [C2mim]+, [C4mim]+ and [C2OHmim]+ also validate the importance of the hydrophobic interactions. The combined effect of cation and anion interactions was explored using 35Cl NMR. Such experiments show that the nature of the cation has no influence on the anion–protein contacts, still the nature of the anion modulates the cation–protein interaction. Herein we propose that more destabilising anions are likely to be a result of a partial contribution from the cation as a direct consequence of the different levels of interaction (cation–anion pair and cation–protein).

Cunha, Jácome, João Paulo Fernandes, Jorge Mendes, Rui Pereira, and João Saraiva. "ES-SQL: Visually Querying Spreadsheets." Proceedings of the 2014 IEEE Symposium on Visual Languages and Human-Centric Computing. VLHCC '14. Washington, DC, USA: IEEE Computer Society, 2014. 203-204. Abstractvlhcc14-td.pdf

This paper presents ES-SQL, an embedded tool for visually constructing queries over spreadsheets. This tool provides an expressive query environment which has knowledge on the business logic of spreadsheets, and by this knowledge it assists the user in defining the intended queries.

Larrinaga, Pello, Carlos Chastre, Hugo C. Biscaia, and José T. San-José. "Experimental and Numerical Modelling of Basalt Textile Reinforced Mortar Behavior Under Uniaxial Tensile Stress." Materials & Design. 55.March (2014): 66-74. AbstractWebsite

During the last years several projects and studies have improved the knowledge about Textile Reinforced Mortar (TRM) technology. TRM has already been used in strengthening masonry and reinforced concrete structural elements such as walls, arches, columns and beams. This material is presented as a real alternative to the use of fibre-reinforced polymers (FRP) in situations where these composites have presented some drawbacks or their use is banned. Textile Reinforced Mortar show a complex mechanical behaviour derived from the heterogeneity of the constituent materials. This paper aims to deepen the knowledge of this composite material in terms of tensile behaviour. Following this scope, this paper presents an experimental campaign focused on thirty one TRM specimens reinforced with four different reinforcing ratios. The results are analysed and contrasted with two distinct models. i) the Aveston-Cooper-Kelly theory (ACK) which is based on a tri-linear analytical approach; and ii) a nonlinear numerical simulation with a 3D Finite Element code. The Finite Element Analysis (FEA) of the TRM tensile tests also showed no significant dependence on the basalt-to-mortar interface, i.e., the choice of a bond-slip curve in order to reproduce the bond stresses and slippages along the interface is irrelevant and it can be simply considered as rigid interface.

Cismaşiu, C., A. Narciso, and F. Amarante dos Santos. "Experimental Dynamic Characterization and Finite Element Updating of a Footbridge Structure." Journal of Performance of Constructed Facilities.10.1061/(ASCE)CF.1943-5509.0000615 (2014).Website