scholarly journals Estimating the long-term returns of effective obesity prevention policies in adolescence: A simulation modeling approach

2015 ◽  
Vol 25 (suppl_3) ◽  
Author(s):  
D Sonntag ◽  
M Jarkzok ◽  
S Ali
2021 ◽  
Vol 11 (8) ◽  
pp. 3487
Author(s):  
Helge Nordal ◽  
Idriss El-Thalji

The introduction of Industry 4.0 is expected to revolutionize current maintenance practices by reaching new levels of predictive (detection, diagnosis, and prognosis processes) and prescriptive maintenance analytics. In general, the new maintenance paradigms (predictive and prescriptive) are often difficult to justify because of their multiple inherent trade-offs and hidden systems causalities. The prediction models, in the literature, can be considered as a “black box” that is missing the links between input data, analysis, and final predictions, which makes the industrial adaptability to such models almost impossible. It is also missing enable modeling deterioration based on loading, or considering technical specifications related to detection, diagnosis, and prognosis, which are all decisive for intelligent maintenance purposes. The purpose and scientific contribution of this paper is to present a novel simulation model that enables estimating the lifetime benefits of an industrial asset when an intelligent maintenance management system is utilized as mixed maintenance strategies and the predictive maintenance (PdM) is leveraged into opportunistic intervals. The multi-method simulation modeling approach combining agent-based modeling with system dynamics is applied with a purposefully selected case study to conceptualize and validate the simulation model. Three maintenance strategies (preventive, corrective, and intelligent) and five different scenarios (case study data, manipulated case study data, offshore and onshore reliability data handbook (OREDA) database, physics-based data, and hybrid) are modeled and simulated for a time period of 20 years (175,200 h). Intelligent maintenance is defined as PdM leveraged in opportunistic maintenance intervals. The results clearly demonstrate the possible lifetime benefits of implementing an intelligent maintenance system into the case study as it enhanced the operational availability by 0.268% and reduced corrective maintenance workload by 459 h or 11%. The multi-method simulation model leverages and shows the effect of the physics-based data (deterioration curves), loading profiles, and detection and prediction levels. It is concluded that implementing intelligent maintenance without an effective predictive horizon of the associated PdM and effective frequency of opportunistic maintenance intervals, does not guarantee the gain of its lifetime benefits. Moreover, the case study maintenance data shall be collected in a complete (no missing data) and more accurate manner (use hours instead of date only) and used to continuously upgrade the failure rates and maintenance times.


2016 ◽  
Vol 01 (02) ◽  
Author(s):  
Lainie Rutkow ◽  
Jesse Jones Smith ◽  
Hannah J Walters ◽  
Marguerite O Hara ◽  
Sara N Bleich

1981 ◽  
Vol 57 (5) ◽  
pp. 233-238 ◽  
Author(s):  
T. H. Hall

This paper describes an approach to forest management decision-making. Acknowledging both objective and subjective elements, the approach offers a methodology to encourage more creative design in forest planning. It uses the descriptive capabilities of simulation modeling in tandem with the prescriptive capabilities of graphical evaluation techniques, to facilitate the use and interpretation of technical forestry information in decision-making problems. It emphasizes a need for an overview of long-term resource behavior as a prerequisite to, and a framework for, forest planning.


2014 ◽  
Vol 85 ◽  
pp. 433-441 ◽  
Author(s):  
Girish Upreti ◽  
Prasanna V. Rao ◽  
Rapinder S. Sawhney ◽  
Isaac Atuahene ◽  
Rajive Dhingra

2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Paul C Langley ◽  
Taeho Greg Rhee

Over the past 20 years a number of simulations or models have been developed as a basis for tracking and evaluating the impact of pharmacological and other interventions in type 1 and type 2 diabetes mellitus. These models have typically tracked the natural course of these diseases generating long-term composite claims for cost-effectiveness. These claims can extend over the lifetime of the modeled patient cohort. Set against the standards of normal science, however, these claims lack credibility. The claims presented are all too often either immune to failure or are presented in a form that is non-testable. As such they fail to meet the key experimental requirements of falsification and replication. Unfortunately, there is a continuing belief that long-term or lifetime models are essential to decision-making. This is misplaced. The purpose of this review is to argue that there is a pressing need to reconsider the needs of health system decision makers and focus on modeled or simulated claims that are meaningful, testable, reportable and replicable in evaluating interventions in diabetes mellitus.   Type: Commentary


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