scholarly journals Characterization of Friction-Stir Welded Joints of AA1100 by Factorial Design Based Hierarchical Regression Model

2020 ◽  
Vol 44 (4) ◽  
pp. 271-280
Author(s):  
Pallavi N. Senapati ◽  
Rajat K. Bhoi
2020 ◽  
Vol 92 (6) ◽  
pp. 7-16
Author(s):  
AKSHANSH MISHRA

In modern computational science, the interplay existing between machine learning and optimization process marks the most vital developments. Optimization plays an important role in mechanical industries because it leads to reduce in material cost, time consumption and increase in production rate. The recent work focuses on performing the optimization task on Friction Stir Welding process for obtaining the maximum Ultimate Tensile Strength (UTS) of the friction stir welded joints. Two machine learning algorithms i.e. Artificial Neural Network (ANN) and Decision Trees regression model are selected for the purpose. The input variables are Tool Rotational Speed (RPM), Tool Traverse Speed (mm/min) and Axial Force (KN) while the output variable is Ultimate Tensile Strength (MPa). It is observed that in case of the Artificial Neural Networks the Root Mean Square Errors for training and testing sets are 0.842 and 0.808 respectively while in case of Decision Trees regression model, the training and testing sets result Root Mean Square Errors of 11.72 and 14.61. So, it can be concluded that ANN algorithm gives better and accurate result than Decision Tree regression algorithm.


ACI Open ◽  
2021 ◽  
Vol 05 (02) ◽  
pp. e59-e66
Author(s):  
Srinivas Emani ◽  
Yichuan Grace Hsieh ◽  
Greg Estey ◽  
Holly M. Parker ◽  
Xiaofeng Zhang ◽  
...  

Abstract Background Recruitment of volunteers is a major challenge for clinical trials. There has been increasing development and use of Internet-based portals in recruitment for clinical research. There has been little research on researcher use and perceptions of these portals. Objectives This study evaluated researcher perceptions of use of Rally, an Internet-based portal for clinical trial volunteer recruitment. Methods A cross-sectional survey was developed and implemented to understand researcher perceptions. From theoretical models of information technology use, the survey adopted items in four domains: ease of use, usefulness, facilitating conditions, and self-efficacy. The dependent variable was researchers' behavioral intention to use Rally. The survey captured characteristics of researchers such as gender, age, and role. It was implemented using the REDCap survey tool. An email invitation followed by three reminders was sent to researchers. A hierarchical regression model was applied to assess predictors of behavioral intention. Results The survey response rate was 35.6% (152 surveys received from 427 contacted researchers). In the hierarchical regression model, facilitating conditions and self-efficacy predicted behavioral intention (F (4,94) = 6.478; p <0.001). The model explained 21.6% of the variance in behavioral intention (R-square change = 21.3%, p <0.001). Conclusion Facilitating conditions and self-efficacy predicted researchers' behavioral intention to use Rally for volunteer recruitment into clinical trials. Future research should document best practices and strategies for enhancing researcher use of online portals for volunteer recruitment.


2018 ◽  
Author(s):  
Jukka Intosalmi ◽  
Henrik Mannerström ◽  
Saara Hiltunen ◽  
Harri Lähdesmäki

AbstractMotivationModern single cell RNA sequencing (scRNA-seq) technologies have made it possible to measure the RNA content of individual cells. The scRNA-seq data provide us with detailed information about the cellular states but, despite several pioneering efforts, it remains an open research question how regulatory networks could be inferred from these noisy discrete read count data.ResultsHere, we introduce a hierarchical regression model which is designed for detecting dependencies in scRNA-seq and other count data. We model count data using the Poisson-log normal distribution and, by means of our hierarchical formulation, detect the dependencies between genes using linear regression model for the latent, cell-specific gene expression rate parameters. The hierarchical formulation allows us to model count data without artificial data transformations and makes it possible to incorporate normalization information directly into the latent layer of the model. We test the proposed approach using both simulated and experimental data. Our results show that the proposed approach performs better than standard regression techniques in parameter inference task as well as in variable selection task.AvailabilityAn implementation of the method is available athttps://github.com/jeintos/[email protected],[email protected]


2021 ◽  
Author(s):  
Jiahao Wang ◽  
Zhengying Chen ◽  
Yiting Liu ◽  
Xiaoli Liao ◽  
Liuxin Long ◽  
...  

Abstract BackgroundEmpathy and death competence are important competences for clinical nurses. However, there is no clear consensus about what impact empathy has on death competency. Our study aimed to understand the status of the empathy and death competence of clinical nurses in China and to explore the effect of empathy on their competence.MethodsFor a survey conducted from May–June 2021, 1415 clinical nurses were selected by convenience sampling as the research objects. The Coping with Death Scale, the Jefferson Scale of Empathy—Health Professionals and a general information questionnaire designed by the researchers were used to investigate the status of the empathy and death competence of clinical nurses. The relationship between empathy and death competence was analysed by Pearson correlation, and the influence of the empathy of clinical nurses on their death competence was analysed by a hierarchical regression model.ResultPearson correlation analysis revealed that death competence was positively correlated with each dimension of empathy. Hierarchical regression model analysis revealed that after controlling for the influence of general information, nurses' empathy had a significant influence on their death competence, and this independently explained 5.8% of the variance in death competence.ConclusionsThe death competence of the clinical nurses in this sample was moderate to low level. Emotional nursing and transposition thinking are important influencing factors of death competence. Nursing managers should improve the empathy of clinical nurses to promote their death competence.


2007 ◽  
Vol 23 (04) ◽  
pp. 215-222
Author(s):  
Vincenzo. Crupi ◽  
Alberto. Marinò ◽  
Marco Biot ◽  
Giacomo. Risitanoison

This paper focuses on the fatigue behavior of aluminum alloy welded joints, which can represent points of weakness in the ship structure. The traditional methods of fatigue assessment of welded joints have some limitations and are extremely time consuming. The Risitano method, based on thermographic analysis, has been applied to overcome these difficulties by predicting the fatigue behavior of welds. Experimental tests have been carried out to assess and compare the fatigue capability(S-N curves, endurance limits) of different welded joints, obtained by means of friction stir welding (FSW) and metal inert gas (MIG) welding. Fatigue predictions obtained resorting to the thermographic method (TM) show good agreement with those derived from the traditional procedure. Thus, TM proves to be a powerful tool also for the characterization of the kind of welded joints mentioned.


2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Saeed Sharifi-Malvajerdi ◽  
Feiyu Zhu ◽  
Colin B. Fogarty ◽  
Michael P. Fay ◽  
Rick M. Fairhurst ◽  
...  

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