Two-stage flexible warranty decision-making considering downtime loss

Author(s):  
Rui Zheng ◽  
Chun Su ◽  
Yuqiao Zheng

Most existing warranty policies are rigid, and the downtime loss is also not taken into account. This study develops a two-stage decision framework to design flexible warranty policies, where the downtime loss is considered. In the first stage, by minimizing the warranty service cost, a fixed warranty policy is provided to determine the baseline of preventive maintenance’s times and effort. In the second stage, customers have three options to increase preventive maintenance times, preventive maintenance effort, or both of them, which results in three types of flexible warranty policies. The additional maintenance cost for the increased preventive maintenance times and/or preventive maintenance effort is paid by the customers. Besides, the flexible policies are optimized to minimize customer’s cost, which is the sum of the downtime loss and shared maintenance cost. A practical example is provided to illustrate the effectiveness of the proposed flexible warranty policies. The results indicate that compared with the fixed warranty policies, both the manufacturer and customers can benefit from the proposed flexible policies, especially when the downtime loss is substantial. Moreover, the proposed policy is more effective when the warranty period is longer.

Author(s):  
Xinlong Li ◽  
Yan Ran ◽  
Genbao Zhang

Preventive maintenance is an important means to extend equipment life and improve equipment reliability. Traditional preventive maintenance decision-making is often based on components or the entire system, the granularity is too large and the decision-making is not accurate enough. The meta-action unit is more refined than the component or system, so the maintenance decision-making based on the meta-action unit is more accurate. Therefore, this paper takes the meta-action unit as the research carrier, considers the imperfect preventive maintenance, based on the hybrid hazard rate model, established the imperfect preventive maintenance optimization model of the meta-action unit, and the optimization solution algorithm was given for the maintenance strategy. Finally, through numerical analysis, the validity of the model is verified, and the influence of different maintenance costs on the optimal maintenance strategy and optimal maintenance cost rate is analyzed.


2021 ◽  
Vol 252 ◽  
pp. 03011
Author(s):  
Jianfeng Yang ◽  
Tianxiang Xie ◽  
Chang Zhang ◽  
Jie Dong ◽  
Jianhao Zhang ◽  
...  

The integrated community energy system (ICES) has aroused considerable attention for its low emission and high operating efficiency. The existing configuration methods for ICES with multi-energy sectors ignored the controllable load. In this paper, a two-stage configuration method of ICES is developed to achieve the minimum annual investing and operating cost. At the first stage, the capacities of components in ICES are optimized to minimize the annual investment cost of ICES. At the second stage, the annual operating cost including the electricity and gas purchase costs and the component maintenance cost is minimized to satisfy the energy load. The controllable load under the time-of-use energy price in seasonal typical days is considered in the second stage. Relevant simulations are conducted to validate the effectiveness of the proposed configuration method for ICES. Considering the controllable load, comparative simulations illustrate that the proposed configuration method can significantly reduce the battery investment cost.


2021 ◽  
Vol 11 (19) ◽  
pp. 9348
Author(s):  
Anna Jodejko-Pietruczuk

Although one can presently observe great development in the methods for diagnosing conditions of technical systems, inspections which are not 100% accurate are still common in industry. If there are multiple available inspection methods which differ in accuracy of diagnosis, cost, or testing time, the answer for the question: which inspection method should be chosen is not a simple task. This paper addresses the problem and proposes a two-stage inspection policy model whose aim is to combine inspection methods that differ in their accuracy and cost features. The two-stage policy models that have been used so far in the literature assume that the second stage of an inspection is perfect, which is not always possible or profitable. For this reason, the mathematical model of the two-stage inspection policy with not-necessarily-perfect second stage is developed here, and its results are presented for the case study of diagnosing sealing in a hydraulic cylinder. The example proved that the application of mixed imperfect inspections could decrease maintenance cost, compared to the one-stage perfect inspection policy, by up to 35%. The paper also formulates a set of rules that support decision making while searching for cost-effective parameters of the two-stage policy. Their application is confirmed by a numerical example, which shows their potential in suboptimization of the proposed policy.


2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Shu-Yen Wan ◽  
Che-Yao Chang ◽  
Chun-Ling Wang ◽  
Kun-Ju Lin

Examination in nuclear medicine exhibits scheduling difficulties due to its intricate clinical issues, such as varied radiopharmaceuticals for different diseases, machine preparation and length of scan, and patients’ and hospital’s criteria and/or limitations. Many scheduling methods exist but are limited for nuclear medicine. In this paper, we present stateless two-stage scheduling to cope with multiple criteria decision making. The first stage mostly deals with patients’ conditions. The second stage concerns more the clinical condition and its correlations with patients’ preference which presents more complicated intertwined configurations. A greedy algorithm is proposed in the second stage to determine the (time slot and patient) pair in linear time. The result shows practical and efficient scheduling for nuclear medicine.


2021 ◽  
pp. 112972982110052
Author(s):  
Mary Ottinger ◽  
Desiree Picone ◽  
Katrina Hseih ◽  
Mathew Wooster ◽  
Mark J London ◽  
...  

Introduction: Transposed brachiobasilic AV fistulas (BVT) have increasingly been performed in two stages. Published reports give conflicting results, perhaps in part as many reports of staged procedures eliminate those patients who “fail” the first stage (i.e. are lost to follow-up in addition to anatomic failure). Methods: A prospectively maintained database was reviewed to identify all patients at two institutions who underwent the first stage of planned two-stage BVT by the senior author. Success in this context was defined as patients who eventually underwent second stage fistula creation, leaving the operating room after the second stage with a patent, transposed fistula. Results: From October 2012 to June 2020, 218 patients underwent first-stage procedures. At the first visit, 185 (85%) of fistulas were patent, 23 (11%) were occluded, 8 (4%) of patients were lost to follow-up, and 2 (1%) died. In the interval before the second operation, another eight (4%) patients were lost to follow-up, two were cancelled for medical reasons, and two declined surgery, leaving a total of 173 patients who made it to the second stage (80%). At operation, four patients were found to have unusable veins, leaving a total of 169 patients who completed both stages. If all patients who underwent first stage are included, 77% of patients entering this pathway left the OR after their second stage with patent access. If those lost to follow-up are excluded, this number increases to 84%, while if all those lost to follow-up are assumed to mature, success increases to 85%. Conclusions: Depending on results in patients lost to follow-up, between 77% and 85% of patients undergoing first stage brachiobasilic fistulae undergo successful second stage transposition. These numbers are equivalent or slightly lower than published maturation rates for single-stage BVT, so there is little margin for failure at the second stage.


Author(s):  
Inbal Hakman ◽  
Alex Mintz ◽  
Steven B. Redd

Poliheuristic theory addresses the “why” and “how” of decision making. It focuses on how decision makers use heuristics en route to choice by addressing both the process and the choice related to the decision task. More specifically, decision makers use a two-stage process wherein a more complicated choice set is reduced to one that is more manageable through the use of these heuristics, or cognitive shortcuts. In the second stage, decision makers are more likely to employ maximizing and analytical strategies in making a choice. Poliheuristic theory also focuses on the political consequences of decision making, arguing that decision makers will refrain from making politically costly decisions. While poliheuristic theory helps us better understand how decision makers process information and make choices, it does not specifically address how choice sets and decision matrices were created in the first place. Applied decision analysis (ADA) rectifies this shortcoming by focusing on how leaders create particular choice sets and matrices and then how they arrive at a choice. It does so by first identifying the decision maker’s choice set or decision matrix; that is, the alternatives or options available to choose from as well as the criteria or dimensions upon which the options will be evaluated. ADA then focuses on uncovering the decision maker’s decision code through the use of multiple decision models. Combining poliheuristic theory with ADA allows researchers to more fully explain decision making in general and crisis decision making in particular. An application of poliheuristic theory and ADA to decision making pertaining to the Fukushima nuclear disaster reveals that even in this high-stress crisis environment decision makers followed the two-stage process as predicted by poliheuristic theory. More specifically, in the first stage, decision makers simplified the decision task by resorting to cognitive heuristics (i.e., decision making shortcuts) to eliminate politically damaging alternatives such as voluntary evacuation. In the second stage, decision makers conducted a more analytical evaluation of the compulsory evacuation options.


2021 ◽  
Author(s):  
Ying He

In this paper, a two-stage evaluation (TSE) model for decision making under ambiguity is proposed. Events in state space are classified into risky and ambiguous events, which correspond to different types of uncertainty generated by different sources. In this TSE model, uncertainty of two different types are evaluated by decision maker (DM) in different stages. In the first stage, DM evaluates more uncertain consequences of an act locally by applying local subjective expected utility (SEU) models, which are then embedded into the second-stage evaluation based on SEU defined globally over all events. To axiomatize such a model, the small domain SEU over risky acts is extended to both risky and nonrisky (ambiguous) acts. When evaluating a risky act, TSE model reduces to Savage’s SEU with one stage. When evaluating an ambiguous act, local SEU with a different uncertainty aversion defined on ambiguous events gives TSE model some flexibility in describing preferences. It can be shown that TSE model can accommodate Ellsberg’s paradoxes and Machina’s paradoxes in the literature. When applied to portfolio selection problem, TSE model enjoys some nice properties other models do not have. This paper was accepted by Manel Baucells, decision analysis.


2017 ◽  
Vol 9 (1) ◽  
pp. 32-48 ◽  
Author(s):  
Rima Oudjedi Damerdji ◽  
Myriam Noureddine

The definition of an appropriated maintenance policy appears essential to avoid the system failures and ensure its optimal operation, while taking into account the criteria of availability and costs. This article deals with a maintenance decision-making for a system subject to two competing maintenance actions, corrective and preventive maintenance. To define this situation of dependent competing risks, the Alert Delay model seems well suited because it involves the notion of a delivered alert before system failure in order to perform preventive maintenance. This paper proposes an approach including both an extension of the Alert Delay model where the considered system follows an exponential distribution, and the total maintenance cost assessment of the system. These two concepts provide an aid decision-making to select the optimal maintenance policy based on the minimal cost. The proposed approach is validated in a computer system localized in a real industrial enterprise.


2013 ◽  
Vol 860-863 ◽  
pp. 383-388 ◽  
Author(s):  
Cheng Cheng Wang ◽  
Yu Jing Gu ◽  
Wei Wei Zhao ◽  
Yan Peng Han ◽  
Yu Liang Dong

In order to insure the safe running of wind turbine in high efficiency under the premise of lowest maintenance cost, preventive maintenance cycles need to be determined reasonable. In this paper, the special operation environment, complicated fault type and diversified situation of wind turbine are full considered, preventive maintenance cycle decision making optimization model is established under the minimum maintenance cost and availability constraints. Finally, gear box system is taken as an example for analysis and calculation to show the feasibility and rationality of model, the results can provide scientific decision basis for planning maintenance of wind turbine.


Author(s):  
Mohammad Rizk Assaf ◽  
Abdel-Nasser Assimi

In this article, the authors investigate the enhanced two stage MMSE (TS-MMSE) equalizer in bit-interleaved coded FBMC/OQAM system which gives a tradeoff between complexity and performance, since error correcting codes limits error propagation, so this allows the equalizer to remove not only ICI but also ISI in the second stage. The proposed equalizer has shown less design complexity compared to the other MMSE equalizers. The obtained results show that the probability of error is improved where SNR gain reaches 2 dB measured at BER compared with ICI cancellation for different types of modulation schemes and ITU Vehicular B channel model. Some simulation results are provided to illustrate the effectiveness of the proposed equalizer.


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