Warranty Period Research Articles

RISK MANAGEMENT DURING AFTER-SALES MAINTENANCE OF GAS TURBINE ENGINES

The justification of necessity and estimated determination of quality indicators of after-sales maintenance of gas turbine engines during the warranty period are given associated with engine transportation, engine’s units and parts transportation and links with determination of construction machinability relating to repair work.

A Higher-Order Markov Model for a Hybrid Inventory System with Probabilistic Remanufacturing Demand

Abstract This study develops a higher-order Markov model (HOM) for an inventory system with remanufacturing, substitution, and lost sales. Defective and disposed items are other factors that are considered in addition to probabilistic demand for both manufacturing and remanufacturing items. One year is the warranty period for items manufactured, and items sold return from customers to the manufacturer in increasing cumulative percentages over the months of the year. To the best our knowledge, a higher-order Markov model has rarely been used in a hybrid inventory system. The challenge is how to determine the steady state of the system with the probable demand for manufacturing and remanufacturing. We propose a new search algorithm to select the best control strategy from several strategies, and then compare it with the two-phase local search algorithm. Each state deals with (12) a probabilistic demand (policy), so the system steady state is set to (22632) policies in total for each production plan. The results showed profit maximization using the new search algorithm compared with the two-phase local search algorithm. Also, an increase in defective and returned items over time, and therefore an increase in remanufactured items. But it does not satisfy all the demand, so manufacturing increases over time due to substitution. Substitution strategy leads to increase the expected average profit.

IMPLEMENTASI FUZZY LOGIC DALAM MENENTUKAN HARGA PERBAIKAN ALTERNATOR MENGGUNAKAN METODE MAMDANI

The alternator is the component of the generator that produces electricity. A short circuit in the alternator causes a surge in electric current so that it can cause an explosion of sparks, it is necessary to prevent an electric short circuit so that maintenance is needed to repair the alternator. Problems in making decisions also occur in companies, in transactions that are used by companies that are still done manually, in determining the price of alternator repairs it is still based on estimates and during the price determination process you have to wait for confirmation from the company's leadership so that the process takes longer and the error rate is relatively high. Fuzzy logic mamdani one method that can be used to overcome this problem. This research will get the best price quickly and minimize the error rate in pricing and adapt it to the implementation design in MATLAB. In the process of determining the repair price, several weighted criteria are required as input variables, namely alternator capacity, level of difficulty and warranty period, which will then produce output variables, namely alternator repair prices. This study aims to assist companies in determining the price of alternator repairs.

TRACKING SALES, INSTALLATION, AND AFTER-SALES SERVICE ACTIVITIES THROUGH PROJECTS

Companies that sell, install and service equipment need a plan for the activities they undertake. Since these activities are carried out in a certain order and are undertaken by different people, it is necessary to improve the information flows within the company and achieve the most effective management of the relationship with the client. This paper is a case study on the need to use planning in activity of a company that sells products that need to be assembled and installed at clients also needs to carry out their maintenance during the warranty and post-warranty period.

Diagnostic and prognostic value of stress CMR imaging to evaluate stable chest pain: a twenty-year meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Assessment of inducible ischemia with stress cardiovascular magnetic resonance (CMR) is recommended in patients with chest pain and intermediate or high pre-test probability of coronary artery disease (CAD). We aimed to provide a contemporary quantitative data synthesis on diagnostic accuracy and prognostic value of stress CMR in patients with stable chest pain syndromes. Methods We performed a prespecified systematic review and meta-analysis of studies published over the last twenty years on the diagnostic and prognostic value of stress CMR (PROSPERO: CRD42022299275). We measured pooled diagnostic indicators, including diagnostic odds ratio (DOR), sensitivity, specificity, area under the curve (AUC), and summary effect size indicators, including odds ratios (ORs) and cumulative annualized event rates (AERs) for all-cause death, cardiovascular death and major adverse cardiac events (MACE). Results We identified 33 diagnostic studies pooling 7,815 individuals (mean age, 62 years, 62% males) and 31 prognostic studies pooling 67,080 patients (mean age, 62 years; 57% males; mean follow-up 3.5 years for a total of 381,357 person-years). Stress CMR yielded a pooled DOR of 26.4 (95%CI:10.6–65.9), a sensitivity of 81% (95%CI:68–89%), a specificity of 86% (95%CI:75–93%), and an AUC of 0.84 (95%CI:0.77–0.89) for the detection of functionally obstructive CAD with fractional flow reserve as the reference test. In subgroup analysis, 3 Tesla imaging yielded higher diagnostic accuracy achieving a DOR of 33.2. Presence of stress-inducible ischemia was associated with higher all-cause mortality (OR:2.0; 95%CI:1.7–2.3), cardiovascular mortality (OR:6.4; 95%CI:4.5–9.1), and increased risk of MACE (OR:5.3; 95%CI:4.0–7.0). AERs for cardiovascular death and MACE were < 1% in patients without stress-inducible ischemia. Conclusion Stress CMR yields high diagnostic accuracy and delivers robust prognostication in patients with stable chest pain and known or suspected CAD, particularly with 3 Tesla imaging. While inducible ischemia portends excess mortality and increased risk of MACE, a negative stress CMR indicates a very low risk of future cardiovascular events, with a warranty period of at least 3.5 years.

Extraction conditions to improve antioxidant and antibacterial activity of carrot seed oil

Competition to secure seeds is intensifying due to an increase in food demand and industrial use of biofuels. Therefore, every year, a large number of seeds are produced, but seeds that have exceeded the warranty period or are of poor quality are also discovered during the inspection process. Therefore, a strategy for utilizing non-commercial seeds as agricultural products is required. In this study, extraction methods for enhancing the antioxidant and antibacterial activities of carrot seed oil from non-commercially available (NG) seeds were explored. For this, the carrot seeds were classified into NG and commercially available grade, and the effects of extraction methods [cold pressed extraction (CE), hexane extraction, and soxhlet extraction] and pretreatments [hydro-priming, freeze-thaw (FT), and microwave] were evaluated. Based on the results of the extraction method evaluation, the CE yield was low, but its biological activity was high, and the method eco-friendly. Therefore, as a result of the pretreatment, high-quality oils with desired physicochemical composition, as well as increased extraction yield and biological activity were achieved. In addition, the optimal pretreatment was found to be five repetitions of FT. The methods described in this study can be used to increase the value of seeds by using NG seeds as useful biological materials.

A study on the adoption intention of cold chain prepared Dishes based on consumer orientation mentality

Background: Cold chain prepared dishes, as a new type of food with low temperature and dual attributes, have attracted more and more attention from consumers. From the perspective of consumers' brand positioning mentality, this study integrated the brand, quality and other attributes of cold chain prepared vegetables, and studied the positioning mentality and adoption behavior of Chinese consumers In this study, three cold-chain prefabricated dishes, "pickled cabbage fish", "tomato Braised beef brisket" and "Huangpi fishball", were selected as investigation objects. Contribution: The contribution of this study is that different food value attributes explain the law of consumers' willingness to adopt cold chain prepared dishes through brand positioning mentality, and find out how different degrees of vulnerability and quality warranty Method: Based on ZMET survey method, product effect data were used to analyze and verify structural equation model. Results: Different value evaluation directly affects consumers' brand positioning mentality, brand positioning mind as an intermediate variable has a significant correlation with adoption intention. The degree of vulnerability moderates the relationship between value evaluation and brand positioning mentality, and the degree of warranty period regulates the relationship between quality value, brand positioning mentality and adoption intention respectively. Conclusion: It also provides new marketing tools and theories for entrepreneurs and marketers in the cold chain food industry, which contributes to the promotion and diffusion of cold chain prepared food for consumers

Determination of optimal warranty length for smart wearable device considering customer complaint

ABSTRACT This study investigates optimal warranty length for a new type of smart wearable device to maximize manufacturer’s profit in a competitive market. Most studies explore optimal warranty length based on product performance without considering customer complaints. In this study, unlike existing models, the optimal warranty length is obtained by maximizing an expected profit function comprising essential factors such as customer complaints, early and late warranty periods, product reliability, and reduced profit, using Bayesian analysis. Managers can effectively integrate these factors, and can be more confident about the accuracy of estimated optimal warranty length. This study’s contribution is to propose a methodology to develop new types of smart wearable devices considering their long-term commercial prospects. Sensitivity analyses indicate that in the early warranty period, managers should be more concerned about average reduced profit due to customer complaints and reduced profit percentage due to complaint handling costs. In the late warranty period, improved profit percentage due to good response to complaints is essential in smart wearable device sales. Consequently, managers should adequately deal with customer complaints about smart wearable devices, whether in the early or late warranty period.

Sensitive product feature integrity and confidentiality using blockchain-based internet of things (IoT) architecture

Small-scale third-party accessories vendors face numerous challenges such as (i) warranty period covered for sensitive product, (ii) malicious induction, and (iii) extract root cause of product failure after customer experienced in the real time usage. Therefore, an advanced industrial environment is necessary to resolve these limitations. It offers strong security levels as well as intelligent root cause detection over failure. In this work, propose a blockchain-based internet of things (IoT) architecture for industry 4.0, which includes a voting decision mechanism for IoT device authentication and fault classification based on device and product trust values, respectively. These values are regularly updated in the historical trust value and machinery database for every successful product transaction and identify a new failure cause to set feature for next iteration set from the defective industrial cloud database. The analytical model and simulation results for correct authentication ensure that the proposed architecture achieves 86% eligibility of accuracy across a high ratio of malicious attacks in less converged time.

Impact of industrial development and machinery and transport equipment on natural resources in South Africa

Recent years have seen increasing attention paid to the industrial processing of natural resources as a possible strategy for industrial development in developing countries that export primary products. The paper examines the effects of industrial development, machinery, and transport equipment on natural resources in South Africa from 1972 to 2020, considering the role of population and economic growth. We apply advanced economic modeling for long-run estimates. The relationship between industrial development and economic growth is significant at a 1% significance level. Population growth and machine and transport equipment are significant at 1% and 5%. Industrial development and economic growth are positively associated with natural resources, while population growth and machinery and transport equipment are negatively associated. The growth of industry led to the development of more industrial land. Industrialization became a part of farming. The South African government should step up existing policies to further decoupling of material resources and economic growth. Measures to consider include integrating life-cycle-oriented approaches, introducing resource fees, charging for environmental damage, or extending legal minimum warranty periods to support longer product lifespans. Identifying new business models focusing on resource efficiency of production processes could result in more value created by the private sector.

Optimization of extended warranty cost for multi-component systems with economic dependence based on group maintenance

During extended warranty (EW) period, maintenance events play a key role in controlling the product systems within normal operations. However, the modelling of failure process and maintenance optimization is complicated owing to the complex features of the product system, namely, components of the multi-component system are interdependent with each other in some form. For the purpose of optimizing the EW pricing decision of the multi-component system scientifically and rationally, taking the series multi-component system with economic dependence sold with EW policy as a research object, this paper optimizes the imperfect preventive maintenance (PM) strategy from the standpoint of EW cost. Taking into consideration adjusting the PM moments of the components in the system, a group maintenance model is developed, in which the system is repaired preventively in accordance with a specified PM base interval. In order to compare with the system EW cost before group maintenance, the system EW cost model before group maintenance is developed. Numerical example demonstrates that offering group maintenance programs can reduce EW cost of the system to a great extent, thereby reducing the EW price, which proves to be a win-win strategy to manufacturers and users.

Warranty cost analysis for products protected by Lemon Laws

ABSTRACT This paper deals with warranty cost analysis for a warranted product protected by lemon laws during the warranty period. The product is declared a lemon if either of two conditions are met: (i) the product has been returned to the dealer k (e.g. k = 4) times to have the failed product fixed, and the manufacturer was unable to repair the problem satisfactorily, or (ii) the product has been out of service more than the prespecified threshold (e.g. 30 days) due to one or more failures. We study two cases – (i) refund and (ii) replacement cases. For (i), if the product turns out to be a lemon then the manufacturer refund the purchase price, and replace with a new one for (ii). Since the complexity involved in the formulation of the expected warranty cost (EWC), a simulation approach is used to evaluate the EWC for the two cases considered. We give numerical examples to illustrate the EWC for refunding and replacement cases and discuss the impact of a reliability and/or quality improvement to reduce the EWC for the two cases.

Infrastructure Management System

Technology cannot be disregarded because it has raised the living standards and sparked revolutions in many facets of contemporary society. In every industry, technology has decreased labor and time requirements, and enhanced production efficiency. A certain technology's innovation eventually makes it a part of society and essential to people's daily lives. The management of infrastructure manually in any organization or institution is a tedious task. In order to make the management of infrastructure in courts automated, an application is developed that maintains every detail of all infrastructures and IT stocks in the courts. Users can view the purchase date, warranty period, and location of the infrastructure in the court. A unique QR code is generated for each piece of furniture and IT stock to access its details. The Infrastructure Management System is touted as a revolution in court management. This application saves time and workload. Moreover, notifications are generated if the service period is nearing, and it would call the service person regarding the repair and service. This management system is found to be effective and efficient.

How Do the Criteria Affect Sustainable Supplier Evaluation? - A Case Study Using Multi-Criteria Decision Analysis Methods in a Fuzzy Environment

Choosing a battery supplier is a vital decision-making problem, for which it is essential to obtain stable evaluations. For such sustainable supplier evaluation, multi-criteria decision analysis (MCDA) methods are often used, as their ability to handle uncertain data gives experts more significant opportunities to consider a broader range of cases. However, given the great number of MCDA approaches, it is challenging to find out which approach is the most appropriate. Therefore, this paper presents a sensitivity analysis on evaluating battery suppliers by ARAS, EDAS, MAIRCA, TOPSIS, and VIKOR methods in a fuzzy environment. The provided study presented similar results for the considered MCDA methods confirmed by the WS similarity measure of rankings and the weighted Spearman correlation . On the other hand, the sensitivity analysis conducted on the considered methods indicated that the most relevant criteria for this problem are transportation cost, delivery time, and warranty period.

Interaction between manufacturer’s recycling strategy and e-commerce platform’s extended warranty service

E-commerce platforms provide extended warranty service (EW) to achieve high profitability. Manufacturers need to distinguish whether consumers have purchased extended warranty services when recycling products. We establish a closed-loop supply chain model with extended warranty service. Three recycling pricing strategies of the manufacturer are discussed: a low recycling price only attracts consumers who do not purchase EW, a high recycling price attracts two types of consumers or discriminatory recycling prices for both types of consumers. The results show that discriminated pricing can attract consumers to participate in product recycling, improving product recycling quantity and saving manufacturing costs. The high recycling price is applicable when the base warranty period is short, and the residual value of the old products is low. The manufacturer and the e-commerce platform can both benefit from the three recycling strategies as compared to non-recycling. Manufacturer’s recycling can increase the price and demand of products, and the proportion of consumers purchasing EW is reduced. We also found that the e-commerce platform will not provide EW when the manufacturer’s base warranty duration is long.

ЭКОЛОГИЧЕСКИ БЕЗОПАСНЫЙ ЖИДКИЙ СМАЗОЧНЫЙ МАТЕРИАЛ ДЛЯ ПИЛЬНЫХ ЦЕПЕЙ НА ОСНОВЕ КОМБИНИРОВАННОЙ ДИСПЕРСИОННОЙ СРЕДЫ

The realization of the synergistic effect is shown on the example of creating of the composite liquid lubricant with improved properties using the combined dispersion medium obtained by mixing of the vegetable and mineral oils. The lubricant for the saw chains and the method of its production are developed. The highly purified mineral oil of group III of the NS-4 brand is added to the rapeseed oil in the amount of 20.0…25.0 wt.%, and the complex of the calcium sulfonate with calcium carbonate in the amount of 1.5…2.0 wt.% is used as a multifunctional additive in the manufacture of this lubricant. The developed lubricant has the following characteristics: kinematic viscosity at 40 °C — 61…63 mm2/s; solidification temperature is –29 °C; flash point — 242…246 °C; welding load — 2,764 N; wear index — 0.39…0.41 mm; mass fraction of free organic acids — 1.3...4.7 mg KOH/g; degree of biodegradability — 88–89 %; warranty period of storage in an open container — 12 months.

Joint optimization of two-dimensional preventive maintenance parameters, technology level and product price under continuous usage rate and agent warranty services

ABSTRACT An efficient two-dimensional warranty model with the possibility of extending after-sale services to the end of the product life is developed in which services in the extended warranty period are assigned to an agent as a transaction side. To control product failures, two factors are taken into account in the proposed model: (1) the manufacturing technology level which results in a different reliability outcome for the product; and (2) a two-dimensional maintenance policy with respect to customers’ usage rate. In addition, in order to adapt the model to reality, we depart from the literature by considering the continuous nature of the usage rate variable. Finally, in order to confirm the effectiveness of the model, some comparative studies are carried out. The obtained results reveal that preventive maintenance (PM) activities lead to a considerable rise in cost savings. Besides, in comparison with one-dimensional PM policies based on product age and usage, using a two-dimensional PM policy improves the economic criteria. Furthermore, the presence of the agent has a great impact on reducing the customer’s cost as well as the failure rate after the basic warranty period.

Consumers' purchasing decisions of a dual-channel supply chain system under return and warranty policies

ABSTRACT With the rapid growth of internet technology, particularly during the COVID-19 pandemic, a major portion of consumers have intended to do online shopping. Also the use of eco-friendly products is essential in today's environment and human health. Thus this paper investigates the consumers' purchasing behaviour towards substitutable non-green and eco-friendly products in a dual-channel (offline and online channels) supply chain system. The manufacturer offers a novel combination of promotions such as a return policy in the online channel and a warranty policy in the offline channel depending on the position and situation of consumers. Here, the environmental burden is reduced by considering remanufacturing/refurbishing used products during the warranty period. Therefore, consumers' demand depends on price, eco-friendliness level, warranty and return agreements. The entire problem is modelled under centralised and decentralised decision-making scenarios. Finally, the profit maximisation problem is formulated and solved in the game theory framework. A series of sensitivity analyses of various parameters is conducted numerically to validate the problem. It is observed that, due to the instant return facility in the online channel, online demand is higher than the offline with a higher warranty period.

Unravelling the potential of social media data analysis to improve the warranty service operation

PurposeWarranty service plays a critical role in sustainability and service continuity and influences customer satisfaction. Considering the role of social networks in customer feedback channels, one of the essential sources to examine the reflection of a product/service is social media mining. This paper aims to identify the frequent product failures through social network mining. Focusing on social media data as a comprehensive and online source to detect warranty issues reveals opportunities for improvement, such as user problems and necessities. This model will detect the causes of defects and prioritize improving components in a product-service system based on FMEA results.Design/methodology/approachOntology-based methods, text mining and sentiment analysis with machine learning methods are performed on social media data to investigate product defects, symptoms and the relationship between warranty plans and customer behaviour. Also, the authors have incorporated multi-source data collection to cover all the possibilities. Then the authors promote a decision support system to help the decision-makers using the FMEA process have a more comprehensive insight through customer feedback. Finally, to validate the accuracy and reliability of the results, the authors used the operational data of a LENOVO laptop from a warranty service centre and classifier performance metrics to compare the authors’ results.FindingsThis study confirms the validity of social media data in detecting customer sentiments and discovering the most defective components and failures of the products/services. In other words, the informative threads are derived through a data preparation process and then are based on analyzing the different features of a failure (issues, symptoms, causes, components, solutions). Using social media data helps gain more accurate online information due to the limitation of warranty periods. In other words, using social media data broadens the scope of data gathering and lets in all feedback from different sources to recognize improvement opportunities.Originality/valueThis work contributes a DSS model using multi-channel social media mining through supervised machine learning for warranty-service improvement based on defect-related discovery to unravel the potential aspects of social networks analysis to predict the most vulnerable components of a product and the main causes of failures that lead to the inputs for the FMEA process and then, a cost optimization. The authors have used social media channels like Twitter, Facebook, Reddit, LENOVO Forums, GitHub, Quora and XDA-Developers to gather data about the LENOVO laptop failures as a case study.

Impact of government subsidy on diagnostic tests decisions of core products in high-end equipment manufacturing

In the high-end equipment manufacturing industry, diagnostic test is a common procedure for core products. The core component supplier could obtain the true quality of its products by implementing diagnostic test during the R&D (research and development) process and adjusting the efforts to achieve better quality. However, diagnostic test is not well implemented due to its high cost. As China’s favorable policies increase in relevant regard, government subsidy becomes an emerging incentive for core product manufacturing. The core product supplier who receive financial incentives usually contributes extra effort to achieve better quality. However, the extra effort comes with a corresponding cost. In addition to this, the supplier has received government subsidy to fund the implementation of diagnostic test. In turn, conducting diagnostic test can provide a safety plug as to whether the supplier should receive government subsidy. To investigate this interaction between the government subsidy adoption decision and the diagnostic test decision, we use game theory to model a supply chain composed of an upstream supplier and a downstream manufacturer, where the supplier is delegated by the manufacturer to research and development a batch of core products and to maintain them during the warranty period. Our research shows that even though government subsidies can provide the supplier with direct financial support, it may still not be adopted. In essence, government subsidy has a bright side and a downside effect on supplier, wherein the former side is the direct financial support and the downside is the extra effort cost. The supplier does not always accept government subsidy because the bright side not always sufficient to cover the downside. Specifically, when diagnostic test is costly or with high-quality products, the supplier will accept subsidy but not perform diagnostic tests regardless of government subsidy. Counterintuitively, if consumer preferences for the product are high, the supplier will choose not to accept government subsidy but to perform diagnostic test. This research contributes to providing some theoretical insights for managers in the high-end equipment manufacturing industry.