Optimal Periodic Replacement Policy Under Discrete Time Frame

Author(s):  
Jinpyo Lee
2012 ◽  
Vol 29 (03) ◽  
pp. 1240020
Author(s):  
FU-MIN CHANG ◽  
YU-HUNG CHIEN

This paper presents the effects of a free minimal repair warranty (FMRW) on the periodic replacement policy under discrete operating circumstance. For the discrete-time periodic replacement policy, a product is preventively replaced at pre-specified operation cycles N, 2N, 3N, … (N = 1, 2, …). When the product fails, a minimal repair is performed at the time of failure and the failure rate is not disturbed by each repair. From the customer's perspective, the cost models are developed for both a warranted and a nonwarranted product, and the corresponding optimal periodic replacement policies are derived such that the long-run expected cost rates are minimized. Under the assumption of the discrete time increasing failure rate (IFR), the existence and uniqueness of the optimal N* are shown, and the impacts of a FMRW on the optimal replacement policies are investigated analytically. We found that the optimal N* for a warranted product should be adjusted toward the end of the warranty period.


Author(s):  
SHEY-HUEI SHEU ◽  
YAN-CHUN CHEN ◽  
LI-HSIU TENG

This investigation considers a generalized inspection policy for a deteriorating production system with general random minimal repair costs. The inspection times for the inspection strategy are assumed to be non-negligible. Additionally, uncertainty probabilities associated with inspections are introduced. Using a dynamic programming formulation, the optimal inspection time for maximizing profit per unit time for a given overhaul/replacement time is determined. Next, the procedure is extended to determine the optimal periodic overhaul/replacement time, as well as the optimal number of inspections and their schedule.


2007 ◽  
Vol 176 (3) ◽  
pp. 1678-1686 ◽  
Author(s):  
Ruey Huei Yeh ◽  
Ming-Yuh Chen ◽  
Chen-Yi Lin

2021 ◽  
Author(s):  
Eduard Dadyan

Abstract For analysis tasks, time counts are of interest – values recorded at some, usually equidistant, points in time. The calculation can be performed at various intervals: after a minute, an hour, a day, a week, a month, or a year, depending on how much detail the process should be analyzed. In time series analysis problems, we deal with discrete-time, when each observation of a parameter forms a time frame. The same can be said about the behavior of Covid-19 over time.In this paper, we solve the problem of predicting Covid-19 diseases in the world using neural networks. This approach is useful when it is necessary to overcome difficulties related to non-stationarity, incompleteness, unknown distribution of data, or when statistical methods are not completely satisfactory. The problem of forecasting is solved with the help of the analytical platform Deductor Studio, developed by specialists of the company Intersoft Lab of the Russian Federation. When solving this problem, appropriate methods were used to clean the data from noise and anomalies, which ensured the quality of building a predictive model and obtaining forecast values for tens of days ahead. The principle of time series forecasting was also demonstrated: import, seasonal detection, cleaning, smoothing, building a predictive model, and predicting Covid-19 diseases in the world using neural technologies for 30 days ahead.


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