Journal of Quality Engineering and Management

Abstract  Typically, in order to evaluate the performance of control charts in the healthcare, the parameters of the control chart are assumed to be known; although usually in practice, these parameters are unknown, and the process parameters should be estimated in Phase I for process monitoring. When the estimated parameters are used instead of their known values, the performance of the control chart is affected. In this paper, first, a risk-adjusted Bernoulli EWMA control chart is proposed. Then, the effect of parameter estimation on in-control performance and out-of-control performance of the proposed control chart is examined. After that, the methods of increasing sample sizes as well as modifying the control limits are used to reduce this effect. The results of simulation studies are reported in terms of average run length, standard deviation of run length and coefficient of variation of run length criteria. The simulation results confirm the reduction of the effect of the parameters estimation by increasing the sample size and correcting the control limits. 

Abstract Supply chain quality management as a systematic approach is defined to improve the performance of organizations by developing the opportunities created by the downstream and upstream communication with suppliers and customers in the organization. Today, companies are compelled to upgrade their product quality in order to establish extensive cooperation with other companies involved in the supply chain. The supply chain quality management provides the necessary conditions for establishing an effective cooperation in the field of supply chain. This article focuses on the critical success factors (CSFs) of supply chain quality management and performance measurement in organizations. For this purpose, first by surveying the literature the key factors were identified; later, seven key factors and 40 sub-factors were modified and verified by interviewing chain management executives and experts. Consequently, in the present study, seven key factors and 40 sub-factors for evaluating supply chain quality management are provided. In this study, in consultation with 30 experts and professors in the field of supply chain a questionnaire was prepared and its reliability was assessed. Further, based on paired comparisons and hierarchical analysis process the prioritization of indices was performed using Expert Choice software and, finally, the status of the company was examined. According to the results, the position of the company with regard to SCQM is not favorable, and more attention should be paid to it. The seven CSFs found in this paper demonstrate that the companies involved in the supply chain of a product should focus on seven domains for the implementation of SCQM. Considering the existing correlation between these domains, they should develop these seven domains simultaneously and with the help of each other. The 40 identified sub-criteria, also known as improvement points or critical points, are considered to be the axis of coordination of chain members in this field. 

  

Abstract  In previous studies, in the discussion of maintenance and repair systems, the evaluation criteria, their classification and the use of different techniques for evaluation have been addressed. But the main issue of this research is to identify the metrics of the system's evaluation and determine their relationship with the processes and goals of the system, to determine the subsystems of the system, identify their relationships and their effects on each other, and provide scenarios that critical paths in the system and the conditions Affecting this Directions are specified.The present study is a qualitative approach in which the theory of data and fuzzy perceptual mapping is used. Using this theory, maintenance subsystems were identified and designed with four main categories: inspection, maintenance and maintenance, chronic failure, acute failure and its relationship. Then, for each of the categories, its characteristics and dimensions were expressed and identified using the paradigm pattern in axial coding under their categories and their relationships. These communications were used as inputs to the fuzzy perceptual mapping topic and through FCM apper software the impact of each of the causative conditions, mediators, strategies and outcomes on each other and different methods of achieving the outcome in each of the inspection, maintenance and maintenance categories, Chronic and acute failure was investigated and presented in the scenario. 

Abstract Many industries are not aware of the after-sales service features and their impact on customer satisfaction. Disappointed customers have become competitors in order to better compete after-sales service. Due to the specific conditions of the liquefied petroleum gas (LPG) industry (harvesting, delivery, transportation, loading, standardization, etc.), researchers have different opinions in the field of customer service. In this regard, the present study was written with the aim of designing an appropriate after-sales service model in the Iranian liquefied gas industry. The combination of fuzzy Delphi method and structural-interpretive modeling with content approach has been used in the design of this model. Since this method is based on the opinion of experts, the opinions of managers and experts involved in the field of liquefied gas industry in Iran, which included 10 people, were used. In this study, fuzzy Delphi method was used to screen the indices. Out of 20 identified indices, only 3 indices of de-fuzzy mean were less than 0.7 and 17 main indices were identified in this industry. Then, structural-interpretive modeling (ISM) and MICMAC analysis were used to cluster the identified components. After analyzing the data, the variables were classified into six different levels and plotted according to the ISM graph relationships. After MICMAC analysis, the variables were divided into three groups of independent or key variables, linked and dependent, and no variables were included in the group of autonomous variables. The results of research in determining the relationships between variables and the type of variables can help to better understand the issue and make appropriate decisions in identifying after-sales service indicators. Attention to the indicators of reliability, reactivity, quality of interactions, agencies and visits according to the output of the structural model show the impact of these indicators in the field of services and in the liquefied gas industry. 

Abstract In this paper, a mathematical model for predicting expected costs to the manufacturer and buyer in pro-rata warranty policy under inflationary conditions is developed. In this model, the cost of individual claims to the manufacturer is limited to fixed cost 𝐶𝐼 whereby the manufacturer carries out all rectification action with a portion of the cost to the customer if the cost of rectification is below a limit 𝐶𝐼. If the cost of rectification exceeds 𝐶𝐼 then the customer pays the difference between the costs of rectification and 𝐶𝐼.based on this model we analyze respectively the expected warranty costs from the perspectives of the manufacturer and the consumer. A real data are executed to demonstrate the applicability of the model. It is proved that, inflation rate, warranty period length and failure parameters impacts the manufacturer and the consumer expected costs. 
 
 

Abstract Quality management is a paradigm shift in management philosophy to improve effectiveness and a source of competitive advantage, innovation and change. The aim of this study was to identify the key factors for the success of TQM and rank them. The present study is applied and descriptive. To collect data, questionnaires based on multi-criteria decision-making methods used in this study were used, which were completed by experts of Akhshan Shiraz Company. Data were analyzed using a combination of fuzzy dimtel approach and fuzzy network analysis. According to the results in the production environment, the factors of commitment of senior management and leadership, human resource management and finally training and learning have the most and the factors of supplier management and modeling have the least effect on success. In general, soft management factors have a greater impact on the success of TQM than soft communication and hard factors.