Predictive Models for the Characterization of Internal Defects in Additive Materials from Active Thermography Sequences Supported by Machine Learning Methods.

The present article addresses a generation of predictive models that assesses the thickness and length of internal defects in additive manufacturing materials. These modes use data from the application of active transient thermography numerical simulation. In this manner, the raised procedure is an ad-hoc hybrid method that integrates finite element simulation and machine learning models using different predictive feature sets and characteristics (i.e., regression, Gaussian regression, support vector machines, multilayer perceptron, and random forest). The performance results for each model were statistically analyzed, evaluated, and compared in terms of predictive performance, processing time, and outlier sensibility to facilitate the choice of a predictive method to obtain the thickness and length of an internal defect from thermographic monitoring. The best model to predictdefect thickness with six thermal features was interaction linear regression. To make predictive models for defect length and thickness, the best model was Gaussian process regression. However, models such as support vector machines also had significative advantages in terms of processing time and adequate performance for certain feature sets. In this way, the results showed that the predictive capability of some types of algorithms could allow for the detection and measurement of internal defects in materials produced by additive manufacturing using active thermography as a non-destructive test.

Consulta de acceso vascular: resultados antes y después de la instauración de un programa multidisciplinar con realización de ecografía doppler de rutina / Vascular access clinic results before and after implementing a multidisciplinary approach adding routine Doppler ultrasound

ANTECEDENTES Y OBJETIVO: El abordaje multidisciplinar y el uso de ecografía doppler (ED) en la creación y vigilancia del acceso vascular (AV) puede mejorar la prevalencia y permeabilidad de las fístulas arteriovenosas (FAV) para hemodiálisis. El objetivo de este estudio es analizar el impacto de una nueva consulta multidisciplinar (CMD) de AV con ED de rutina. MATERIAL Y MÉTODOS: Evaluamos los resultados de la consulta de AV en 2014 (pre-CMD) y 2015 (CMD), antes y después de la implantación de un equipo multidisciplinar (cirujano vascular/nefrólogo) con ED de rutina en mapeo prequirúrgico y FAV prevalente. RESULTADOS: Se evaluaron 345 pacientes en 2014 (pre-CMD) y 364 pacientes en 2015 (CMD). En ambos periodos se realizó un número similar de cirugías, 172 vs. 198, p = 0,289, con tendencia a aumentar las cirugías preventivas de reparación de FAV en el periodo CMD, 17 vs. 29 (p = 0,098). En FAV de nueva creación (155 vs. 169), disminuyó la tasa de fallo primario en el periodo CMD, 26,4 vs. 15,3%, p = 0,015 y aumentó de forma no significativa la realización de FAV radiocefálicas distales, 25,8 vs. 33,2% (n = 40 vs. 56), p = 0,159. También aumentó la concordancia entre la indicación quirúrgica en la consulta y la cirugía realizada (81,3 vs. 93,5%, p = 0,001). En el periodo CMD se solicitaron menos exploraciones radiológicas desde la consulta, 78 vs. 35 (p < 0,001), con una reducción del gasto sanitario (81.716€ vs. 59.445€). CONCLUSIONES: El manejo multidisciplinar y la utilización del ED de rutina permiten mejorar los resultados de AV, con disminución de la tasa de fallo primario de FAV, más opciones de FAV distal nativa, mejor manejo de la FAV prevalente disfuncionante y menor coste en exploraciones radiológicas

BACKGROUND: A multidisciplinary approach and Doppler ultrasound (DU) assessment for the creation and maintenance of arteriovenous fistulas (AVF) for haemodialysis can improve prevalence and patency. The aim of this study was to analyse the impact of a new multidisciplinary vascular access (VA) clinic with routine DU. MATERIAL AND METHODS: We analysed the VA clinic results from 2014 and 2015, before and after the implementation of a multidisciplinary team protocol (vascular surgeon/nephrologist) with routine DU in preoperative mapping and prevalent AVF. RESULTS: We analysed 345 and 364 patients from 2014 and 2015 respectively. The number of surgical interventions was similar in both periods (p = .289), with a trend towards an increase in preventive surgical repair of AVF in 2015 (17 vs. 29, p = .098). 155 vs. 169 new AVF were performed in 2014 and 2015, with a significantly lower primary failure rate in 2015 (26.4 vs. 15.3%, p = .015), and a non-significant increase in radiocephalic AVF, 25.8 vs. 33.2% (n = 40 vs. 56), p = .159. The concordance between the indication at the clinic and the surgery performed also increased (81.3 vs. 93.5%, p = .001). Throughout 2015 fewer complementary imaging test were requested from the clinic (78 vs. 35, p < .001), with a corresponding reduction in costs (€87,716 vs. €59,445). CONCLUSIONS: Multidisciplinary approach with routine DU can improve VA results, with a decrease in primary failure rate, higher likelihood of radiocephalic AVF, better management of dis-functioning AVF and lower radiological test costs

Vascular access clinic results before and after implementing a multidisciplinary approach adding routine Doppler ultrasound. / Consulta de acceso vascular: resultados antes y después de la instauración de un programa multidisciplinar con realización de ecografía doppler de rutina.

BACKGROUND: A multidisciplinary approach and Doppler ultrasound (DU) assessment for the creation and maintenance of arteriovenous fistulas (AVF) for haemodialysis can improve prevalence and patency. The aim of this study was to analyse the impact of a new multidisciplinary vascular access (VA) clinic with routine DU. MATERIAL AND METHODS: We analysed the VA clinic results from 2014 and 2015, before and after the implementation of a multidisciplinary team protocol (vascular surgeon/nephrologist) with routine DU in preoperative mapping and prevalent AVF. RESULTS: We analysed 345 and 364 patients from 2014 and 2015 respectively. The number of surgical interventions was similar in both periods (p=.289), with a trend towards an increase in preventive surgical repair of AVF in 2015 (17 vs. 29, p=.098). 155 vs. 169 new AVF were performed in 2014 and 2015, with a significantly lower primary failure rate in 2015 (26.4 vs. 15.3%, p=.015), and a non-significant increase in radiocephalic AVF, 25.8 vs. 33.2% (n=40 vs. 56), p=.159. The concordance between the indication at the clinic and the surgery performed also increased (81.3 vs. 93.5%, p=.001). Throughout 2015 fewer complementary imaging test were requested from the clinic (78 vs. 35, p <.001), with a corresponding reduction in costs (€87,716 vs. €59,445). CONCLUSIONS: Multidisciplinary approach with routine DU can improve VA results, with a decrease in primary failure rate, higher likelihood of radiocephalic AVF, better management of dis-functioning AVF and lower radiological test costs.