2018
Autores
Santos, DF; Rodrigues, PP;
Publicação
31st IEEE International Symposium on Computer-Based Medical Systems, CBMS 2018, Karlstad, Sweden, June 18-21, 2018
Abstract
Obstructive sleep apnea (OSA) is a significant sleep problem with various clinical presentations that have not been formally characterized. This poses critical challenges for its recognition, resulting in missed or delayed diagnosis. Recently, cluster analysis has been used in different clinical domains, particularly within numeric variables. We applied an extension of k-means to be used in categorical variables: k-modes, to identify groups of OSA patients. Demographic, physical examination, clinical history, and comorbidities characterization variables (n=46) were collected from 318 patients; missing values were all imputed with k-nearest neighbors (k-NN). Feature selection, through Chi-square test, was executed and 17 variables were inserted in cluster analysis, resulting in three clusters. Cluster 1 having an age between 65 and 90 years (54%), 78% of males, with the presence of diabetes and gastroesophageal reflux, and high OSA prevalence; Cluster 2 presented a lower percentage of OSA (46%), with middle-aged women without comorbidities, but with gastroesophageal reflux; and Cluster 3 was very similar to cluster 1, only differing in age (45-64) and comorbidities were not present. Our results suggest that there are different groups of OSA patients, creating the need to rethink the baseline characteristics of these patients before being sent to perform polysomnography (gold standard exam for diagnosis). © 2018 IEEE.
2018
Autores
Ferreira Santos, D; Pereira Rodrigues, P;
Publicação
DECISION SUPPORT SYSTEMS AND EDUCATION: HELP AND SUPPORT IN HEALTHCARE
Abstract
The varied phenotypes of obstructive sleep apnea (OSA) poses critical challenges, resulting in missed or delayed diagnosis. In this work, we applied k-modes, aiming to identify groups of OSA patients, based on demographic, physical examination, clinical history, and comorbidities characterization variables (n=41) collected from 318 patients. Missing values were imputed with k-nearest neighbours (k-NN) and chi-square test was held. Thirteen variables were inserted in cluster analysis, resulting in three clusters. Cluster 1 were middle-aged men, while Cluster 3 were the oldest men and Cluster 2 mainly middle-aged women. Cluster 3 weighted the most, whereas Cluster 1 weighted the least. The same effect was described in increased neck circumference. The percentages of variables driving sleepiness, congestive heart failure, arrhythmias and pulmonary hypertension were very low (<20%) and OSA severity was more common in mild level. Our results suggest that it is possible to phenotype OSA patients in an objective way, as also, different (although not considered innovative) visualizations improve the recognition of this common sleep pathology.
2018
Autores
Rodrigues, PP; Ferreira Santos, D; Silva, A; Polonia, J; Ribeiro Vaza, I;
Publicação
ARTIFICIAL INTELLIGENCE IN MEDICINE
Abstract
In pharmacovigilance, reported cases are considered suspected adverse drug reactions (ADR). Health authorities have thus adopted structured causality assessment methods, allowing the evaluation of the likelihood that a drug was the causal agent of an adverse reaction. The aim of this work was to develop and validate a new causality assessment support system used in a regional pharmacovigilance centre. A Bayesian network was developed, for which the structure was defined by experts while the parameters were learnt from 593 completely filled ADR reports evaluated by the Portuguese Northern Pharmacovigilance Centre medical expert between 2000 and 2012. Precision, recall and time to causality assessment (TTA) was evaluated, according to the WHO causality assessment guidelines, in a retrospective cohort of 466 reports (April-September 2014) and a prospective cohort of 1041 reports (January-December 2015). Additionally, a simplified assessment matrix was derived from the model, enabling its preliminary direct use by notifiers. Results show that the network was able to easily identify the higher levels of causality (recall above 80%), although struggling to assess reports with a lower level of causality. Nonetheless, the median (Q1:Q3) ITA was 4 (2:8) days using the network and 8 (5:14) days using global introspection, meaning the network allowed a faster time to assessment, which has a procedural deadline of 30 days, improving daily activities in the centre. The matrix expressed similar validity, allowing an immediate feedback to the notifiers, which may result in better future engagement of patients and health professionals in the pharmacovigilance system.
2018
Autores
Ferreira-Santos, D; Rodrigues, PP;
Publicação
International Journal of Data Science and Analytics
Abstract
2018
Autores
De Lima P.V.S.G.; Bezerra M.H.R.A.; De Sousa Tavares A.C.; Jose Roberto Fonseca J.; Teixeira J.M.X.N.; Cajueiro J.P.C.; Melo G.N.; Henriques D.B.;
Publicação
Proceedings - 15th Latin American Robotics Symposium, 6th Brazilian Robotics Symposium and 9th Workshop on Robotics in Education, LARS/SBR/WRE 2018
Abstract
Line-following robots have the ability to recognize and follow a line drawn on a surface. Elements of their operating principles could be used in the evelopment of numerous autonomous technologies, with applications in education and industry. A simulator has been developed to aide in performing several trials in order to validate a project. By taking the Pololu 3pi Robot as the model, the proposed solution simulates its physical structure, behavior, and operations-being able to read lines on surfaces-enabling the user to observe the robot following the line according to the code used. This paper aims to validate the developed simulator as an alternative to ease the process of learning to use the 3pi platform applied in both educational and competitive environments.
2018
Autores
Fonseca, SJR; de Lima, PVSG; Bezerra, MHRA; Teixeira, JMXN; Cajueiro, JPC;
Publicação
15TH LATIN AMERICAN ROBOTICS SYMPOSIUM 6TH BRAZILIAN ROBOTICS SYMPOSIUM 9TH WORKSHOP ON ROBOTICS IN EDUCATION (LARS/SBR/WRE 2018)
Abstract
Line-following robots have the ability to recognize and follow a line drawn on a surface. It works based on a simple self-sustainable system composed with a set of sensors, motors and a controller. In order to get optimal performance in such robots, it's necessary to carry out several tests to evaluate the behavior in each trial. In the majority of cases, a new trial requires to upload a new program, thus slowing down the development of the line-following. This paper presents an approach to solve the inconvenience of having to upload a new program in each trial. It consists in merging multiple codes in to one to create a program that gives the user the ability to switch between them anytime inside Pololu's 3pi line follower platform.
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