scholarly journals Inference about Time-dependent Prognostic Accuracy Measures in the Presence of Competing Risks

2020 ◽  
Author(s):  
Rajib Dey ◽  
Giada Sebastiani ◽  
Paramita Saha-Chaudhuri
Keyword(s):  
Competing Risks ◽  
Model Development ◽  
Real Life ◽  
Small Samples ◽  
Survival Times ◽  
Computationally Efficient ◽  
Time To Event ◽  
Fractional Polynomials ◽  
Prognostic Accuracy ◽  
Time Specific

Abstract Background: Evaluating a candidate marker or developing a model for predicting risk of future conditions is one of the major goals in medicine. However, model development and assessment for a time-to-event outcome may be complicated in the presence of competing risks. In this manuscript, we propose local and global estimators of cause-specific AUC for right-censored survival times in the presence of competing risks. Methods: The local estimator - cause-specific weighted mean rank (cWMR) - is a local average of time-specific observed cause-specific AUCs within a neighborhood of given time t. The global estimator - cause-specific fractional polynomials (cFPL) - is based on modelling the cause-specific AUC as a function of t through fractional polynomials. Results: We investigated the performance of the proposed cWMR and cFPL estimators through simulation studies and real-life data analysis. The estimators perform well in small samples, have minimal bias and appropriate coverage. Conclusions: The local estimator cWMR and the global estimator cFPL will provide computationally efficient options for assessing the prognostic accuracy of markers for time-to-event outcome in the presence of competing risks in many practical settings.

scholarly journals Inference about Time-dependent Prognostic Accuracy Measures in the Presence of Competing Risks

2020 ◽  
Author(s):  
Rajib Dey ◽  
Giada Sebastiani ◽  
Paramita Saha-Chaudhuri
Keyword(s):  
Competing Risks ◽  
Model Development ◽  
Real Life ◽  
Small Samples ◽  
Survival Times ◽  
Computationally Efficient ◽  
Time To Event ◽  
Fractional Polynomials ◽  
Prognostic Accuracy ◽  
Time Specific

Abstract Background: Evaluating a candidate marker or developing a model for predicting risk of future conditions is one of the major goals in medicine. However, model development and assessment for a time-to-event outcome may be complicated in the presence of competing risks. In this manuscript, we propose local and global estimators of cause-specific AUC for right-censored survival times in the presence of competing risks. Methods: The local estimator - cause-specific weighted mean rank (cWMR) - is a local average of time-specific observed cause-specific AUCs within a neighborhood of given time t. The global estimator - cause-specific fractional polynomials (cFPL) - is based on modelling the cause-specific AUC as a function of t through fractional polynomials. Results: We investigated the performance of the proposed cWMR and cFPL estimators through simulation studies and real-life data analysis. The estimators perform well in small samples, have minimal bias and appropriate coverage. Conclusions: The local estimator cWMR and the global estimator cFPL will provide computationally efficient options for assessing the prognostic accuracy of markers for time-to-event outcome in the presence of competing risks in many practical settings.

scholarly journals Application of Artificial Intelligence (AI) for Sustainable Highway and Road System

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Md Arifuzzaman ◽  
Muhammad Aniq Gul ◽  
Kaffayatullah Khan ◽  
S. M. Zakir Hossain
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Adhesion Force ◽  
Model Development ◽  
Real Life ◽  
Bayesian Optimization ◽  
Support Vector ◽  
Adhesive Properties ◽  
Bayesian Optimization Algorithm ◽  
The Mean

There are several environmental factors such as temperature differential, moisture, oxidation, etc. that affect the extended life of the modified asphalt influencing its desired adhesive properties. Knowledge of the properties of asphalt adhesives can help to provide a more resilient and durable asphalt surface. In this study, a hybrid of Bayesian optimization algorithm and support vector regression approach is recommended to predict the adhesion force of asphalt. The effects of three important variables viz., conditions (fresh, wet and aged), binder types (base, 4% SB, 5% SB, 4% SBS and 5% SBS), and Carbon Nano Tube doses (0.5%, 1.0% and 1.5%) on adhesive force are taken into consideration. Real-life experimental data (405 specimens) are considered for model development. Using atomic force microscopy, the adhesive strength of nanoscales of test specimens is determined according to functional groups on the asphalt. It is found that the model predictions overlap with the experimental data with a high R2 of 90.5% and relative deviation are scattered around zero line. Besides, the mean, median and standard deviations of experimental and the predicted values are very close. In addition, the mean absolute Error, root mean square error and fractional bias values were found to be low, indicating the high performance of the developed model.

scholarly journals Modeling potential time to event data with competing risks

2013 ◽  
Vol 20 (2) ◽  
pp. 316-334 ◽  
Author(s):  
Liang Li ◽  
Bo Hu ◽  
Michael W. Kattan
Keyword(s):  
Competing Risks ◽  
Event Data ◽  
Time To Event ◽  
Time To Event Data

scholarly journals Quantifying the predictive accuracy of time-to-event models in the presence of competing risks

2011 ◽  
Vol 53 (1) ◽  
pp. 88-112 ◽  
Author(s):  
Rotraut Schoop ◽  
Jan Beyersmann ◽  
Martin Schumacher ◽  
Harald Binder
Keyword(s):  
Competing Risks ◽  
Predictive Accuracy ◽  
Time To Event ◽  
Event Models

scholarly journals Constructing the Localization of Marxism in Teaching

2020 ◽  
Vol 9 (3) ◽  
pp. 69
Author(s):  
Chufang Hu
Keyword(s):  
Real Life ◽  
The State ◽  
Human Society ◽  
Chinese People ◽  
Specific Time ◽  
New Era ◽  
Time Specific ◽  
Chinese Modernization

<p>The production of any kind of theory has its special and specific environment. Therefore, although truth can be universally applicable, it also needs to be associated with specific time, specific events, and specific environments in the process of combining it with practice, so that the truth can fully spread its wisdom, guide real life, and guide human society to develop scientifically and orderly. Based on the premise of fully understanding Marxism, this paper explores the localization of constructing Marxism in teaching based on the state of China. It proposes that it is necessary to fully integrate China's actual national conditions and realize the localization of Marxism in teaching from Chinese modernization, popularization, <em>etc.</em> in the new era, so as to fully integrate Marxism in China's new era of socialist construction, so that the Chinese people can get a sense of happiness in the localization of Marxism beliefs.</p>

The Role of Business Model Development in the Ex-Post Creation of Online Entrepreneurial Opportunity

2017 ◽  
pp. 818-842
Author(s):  
İpek Koçoğlu ◽  
Ali E. Akgun ◽  
Halit Keskin
Keyword(s):  
Business Model ◽  
Model Development ◽  
Real Life ◽  
Social Infrastructure ◽  
Entrepreneurial Opportunity ◽  
Ex Post ◽  
The Creation ◽  
Online Entrepreneurs ◽  
Business Model Development

This research aims to tap into the largely opaque origins of opportunities in the online context by exploring the role of business model development as a key for the creation and configuration of the mental and social infrastructure necessary for the emergence of online entrepreneurial opportunity. Tracing the sources of online entrepreneurial opportunity reveals that successful online entrepreneurs claim to proactively manage their environment in terms of unfolding actions which result in the enactment and creation of entrepreneurial opportunities. Based on this real life contention and the emerging view of entrepreneurial opportunity, this chapter aims to achieve a deeper understanding on the creation of online opportunities through a quantitative study empirically testing the link between business model development and online entrepreneurial opportunity as creation in order to shed light on how business model generation shapes the way entrepreneurs socially co-create opportunities in the online context.

Survival analysis

2020 ◽  
pp. 181-218
Author(s):  
Bendix Carstensen
Keyword(s):  
Survival Analysis ◽  
Competing Risks ◽  
Cox Model ◽  
Survival Function ◽  
Event Analysis ◽  
Time To Event ◽  
Poisson Models ◽  
Kaplan Meier ◽  
Analysis Survival ◽  
Event Rates

This chapter describes survival analysis. Survival analysis concerns data where the outcome is a length of time, namely the time from inclusion in the study (such as diagnosis of some disease) till death or some other event — hence the term 'time to event analysis', which is also used. There are two primary targets normally addressed in survival analysis: survival probabilities and event rates. The chapter then looks at the life table estimator of survival function and the Kaplan–Meier estimator of survival. It also considers the Cox model and its relationship with Poisson models, as well as the Fine–Gray approach to competing risks.

scholarly journals Bayesian splines versus fractional polynomials in network meta-analysis

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Andreas Heinecke ◽  
Marta Tallarita ◽  
Maria De Iorio
Keyword(s):  
Meta Analysis ◽  
Indirect Comparison ◽  
Real Data ◽  
Multiple Time ◽  
Computationally Efficient ◽  
Fractional Polynomials ◽  
Time Points ◽  
Model Based ◽  
Multiple Treatments ◽  
Indirect Comparisons

Abstract Background Network meta-analysis (NMA) provides a powerful tool for the simultaneous evaluation of multiple treatments by combining evidence from different studies, allowing for direct and indirect comparisons between treatments. In recent years, NMA is becoming increasingly popular in the medical literature and underlying statistical methodologies are evolving both in the frequentist and Bayesian framework. Traditional NMA models are often based on the comparison of two treatment arms per study. These individual studies may measure outcomes at multiple time points that are not necessarily homogeneous across studies. Methods In this article we present a Bayesian model based on B-splines for the simultaneous analysis of outcomes across time points, that allows for indirect comparison of treatments across different longitudinal studies. Results We illustrate the proposed approach in simulations as well as on real data examples available in the literature and compare it with a model based on P-splines and one based on fractional polynomials, showing that our approach is flexible and overcomes the limitations of the latter. Conclusions The proposed approach is computationally efficient and able to accommodate a large class of temporal treatment effect patterns, allowing for direct and indirect comparisons of widely varying shapes of longitudinal profiles.

scholarly journals Design Gamification Models in Higher Education: A Study in Indonesia

2020 ◽  
Vol 15 (12) ◽  
pp. 244
Author(s):  
Isabel Coryunitha Panis ◽  
Punaji Setyosari ◽  
Dedi Kuswandi ◽  
Lia Yuliati
Keyword(s):  
Model Validation ◽  
Model Development ◽  
Real Life ◽  
Problem Based Learning ◽  
Theory And Practice ◽  
Average Score ◽  
Learning Needs ◽  
Learning Design ◽  
Tertiary Institutions ◽  
Overall Evaluation

Based on the data, it is known that the average score of the overall evaluation aspects of the learning design reached 3.4. This figure according to the results of the conversion of quantitative data to qualitative data on scale 4 belongs to the very good category, which means that the learning design of gamified problem-based learning developed is feasible to be applied in learning. The purpose of writing this article is to develop an appropriate gamification model in tertiary institutions which links gamification theory and problem based learning into a new model that will later be combined with existing learning media to become more effective and interesting when applied in each course. Research on learning design models can be classified into three types: model development, model validation, and model use. This study examines the first two points above, which are based on research methodologies for model development and model validation where learning models are developed either practically or theoretically. In theory, the cause is based on the literature related to the model that is to be developed, being practical because it must be based on a learning design that is suitable for real life. The gamified problem-based learning design model has been based on literature and has projected real-life learning needs. In the results, it is known that the effectiveness and attractiveness of the design of gamified problem based learning as teaching material in the form of theory and practice have shown results in the excellent category which means that this learning design is feasible to be applied in learning.

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