Browsing by Author "Figueiredo, E."
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- Applicability of a Markov-chain Monte Carlo method for damage detection on data from the Z-24 and Tamar suspension bridgesPublication . Figueiredo, E.; Radu, L.; Westgate, R.; Brownjohn, J.; Cross, E.; Worden, K.; Farrar, C.In the Structural Health Monitoring of bridges, the effects of the operational and environmental variability on the structural responses have posed several challenges for early damage detection. In order to overcome those challenges, in the last decade recourse has been made to the statistical pattern recognition paradigm based on vibration data from long-term monitoring. The use of purely data-based algorithms that do not depend on the physical descriptions of the structures have characterized this paradigm. However, one drawback of this procedure is how to set up the baseline condition for new and existing bridges. Therefore, this paper proposes an algorithm with a Bayesian approach based on a Markov-chain Monte Carlo method to cluster structural responses of the bridges into a reduced number of global state conditions, by taking into account eventual multimodality and heterogeneity of the data distribution. This approach, along with the Mahalanobis squared-distance, permits one to form an algorithm able to detect structural damage based on daily response data even under abnormal events caused by operational and environmental variability. The applicability of this approach is first demonstrated on standard data sets from the Z-24 Bridge, Switzerland. Afterwards, for generalization purposes, it is applied on datasets from a supposed undamaged bridge condition, namely the Tamar Bridge, England. The analysis suggests that this algorithm might be useful for bridge applications, because it permits one to overcome some of the limitations posed by the pattern recognition paradigm, especially when dealing with limited amounts of training data.
- Knowledge and behavior among health professionals in relation to cadaveric organ donation and transplantation: a questionnaire-based analysis in Portuguese HospitalsPublication . Melo, J.; Batista, A.; Teixeira, A.; Figueiredo, E.; Ribeiro, O.; Lopes, P.; Pina, J.; Granja, C.; Carvalho, A. S.Objective. To assess knowledge and behavior relative to cadaveric organ donation and transplantation among physicians and nurses working at nine Portuguese hospitals. Methods. This prospective study between May and October 2009 included 495 questionnaires that were returned among 840 that were delivered, a 59% response rate. The transplant questionnaire comprised three main sections: section 1, sociodemographic-professional variables of the participants with nine questions; section 2, generic questions on organ donation and transplantation with 12 questions; and section 3 evaluated knowledge with 20 specific questions on organ donation and transplantation. Results. Sixty-one percent of the participants were females, with 40% of the overall cohort between 31 and 40 years old; 62% married; 63% working in the emergency department; and 78% nurses. Although 78% of the participants stated that they had undergone specific training on organ donation and transplantation, 62% felt that they needed more training. The reasons evoked for the low rate of donation included difficulties in initiating the process of organ donation, in diagnosing cerebral death and in obtaining necessary human resources. There were no significant differences in knowledge between physicians and nurses concerning specific organ donation and transplantation issues. Having had specific training on organ donation and transplantation was significantly associated with correct answers to several questions, including those pertaining to knowledge of the national legislation on organ donation and transplantation. Conclusions. The present study showed a lack of specific knowledge and training on organ donation and transplantation issue. It also suggested that for hospital staff to successfully act as initiators of the organ procurement process, more information and education are necessary. This effort could significantly increase the rate of organ donation and transplantation in Portugal.