Journal of Quality Engineering and Management

Abstract Purpose: The objective of the present study is to determine an optimal configuration in terms of the type and number of components in order to maximize system availability and reduce costs, using an active redundancy allocation strategy, while considering load-sharing capability and the use of maintenance personnel under maintenance and leave policies, in the electrical power distribution system of a marine vessel. In the active redundancy strategy, all additional components and subsystems are operated simultaneously from the start of system operation, and the system fails only when all components have failed.
Methodology: In this study, a bi-objective model is developed for an electrical power distribution system with active redundancy in a marine vessel, where the first objective is minimization of total cost and the second objective is maximization of system availability. System behavior is simulated using a Markov chain and a phase-type distribution, and the model is solved using the Non-dominated Sorting Genetic Algorithm II (NSGA-II). Failure of one component affects the failure rates of other components within the same subsystem, leading to an increase in their failure rates. In other words, the problem is analyzed under a load-sharing condition. A single repairman is considered for equipment repair. The maintenance and leave policy is defined such that if a component fails during the repairman’s leave period, the leave is terminated and repair of the failed component begins immediately. If another component fails while a component is under repair, it is placed in a repair queue, and the repairman starts repairing the next failed component immediately after completing the repair of the previous one. When the repairman is on leave and no component failure occurs, the repairman may resume the leave period.
Findings: The results of the study identify the optimal combination of the type and number of electrical power distribution panels in each subsystem of the vessel’s electrical power distribution system, aimed at increasing system availability and reducing costs through the use of active redundancy. In addition, the results provide the probability of the repairman being busy, which can support managerial decision-making regarding maintenance and leave policies.
Originality/Value: Considering the innovative aspects of the study, the results can be effectively used for engineering analyses, particularly in evaluating system availability, as well as for managerial analyses, including cost estimation and the allocation of maintenance personnel.

Abstract Purpose: Multivariate and multi-state processes refer to types of processes that involve a large number of variables at each production stage, which may be interrelated. The objective of this study is to propose a novel approach for selecting, reducing, and defining new control variables in complex manufacturing processes, enabling more effective and efficient quality control.
Methodology: This study employs an applied, descriptive research methodology. Machine learning techniques and dimensionality reduction methods, such as Principal Component Analysis (PCA), are utilized, along with regression and correlation analysis. To evaluate the proposed method, a case study was conducted using real production data from the slab manufacturing process at Mobarakeh Steel Company in Isfahan.
Findings: The slab production process consisted of three main stages: furnace, secondary metallurgy, and casting. In each stage, the proposed method was applied to reduce the number of control variables. For instance, in the furnace unit, nine initial variables were grouped into three clusters, and correlation and PCA were applied within each group. Key variables were extracted, and experts validated the results. The findings indicated that this approach effectively reduces the number of quality-related variables.
Originality/Value: The novelty of this research lies in integrating machine learning and dimensionality reduction techniques to optimize quality control in multistage, multivariate processes. This method provides an effective tool for quality engineers and process analysts, particularly when traditional methods prove ineffective.

Abstract Allocation is one of the important activities in the reliability process, if it is not done correctly, it will not be possible to achieve the reliability goals for the whole system. To allocate the reliability, methods have been presented that are not free of defects. In this research, five factors of complexity, new technology, operation time, environment and resilience of subsystems are considered and the goal is to consider a new approach in allocating reliability to the goal feasibility method so that different parts and subsystems can be examined and measured based on the desired reliability and resilience. The obtained results are investigated and measured by Foo method with the mentioned five factors and finally validated.
The following items are suggested to researchers in the field of reliability and complex systems:
• Consider the development of each of the four factors in Fu's method in their research.
• Considering this research as a basis, the presented method should be developed in terms of management as well as providing other combined solutions.
• After the development of other factors of Foo's method, software can be developed to assign reliability.
• Designing a mathematical model for assigning reliability so that it includes more factors.
• Finding a quantitative relationship between the cost of a subsystem and its reliability so that the system cost is minimized under the reliability constraint or the system reliability is maximized under the cost constraint.

Abstract Despite the important issue of high-reliability organizations, it has not been adequately addressed in our country. Scientific designs that can accurately assess organizations and various assessments and evaluations in the situations of organizations and the possibility of decision-making of organizations and improvement programs are decisive. This aims to provide a comprehensive research need for evaluating high-reliability blocks. In this research, the meta-synthesis method has been used, during which, based on the seventh-stage method of Sandelowski and Barroso, related sources and models have been examined and analyzed, and finally, a five-level model with a comprehensive view has been designed, in which at each level, the characteristics of determining the maturity level have been presented. This model can be used to evaluate and analyze the maturity level of high-reliability organizations, as well as to design an improvement and development program for these organizations.

Abstract Abstract: Since the development of a strong platform architecture is considered a competitive advantage for companies and is effective in improving the future generations of the product, therefore there is a need for a kind of diversified product design that simultaneously manages the costs and supply chain process and thus help to develop the architecture of the product platform. In this research, the design for vareity (DFV) method and two generational variety index (GVI) and coupling index (CI) are used to measure a product architecture and by using the quality improvement function (QFD) and the design structure matrix ( DSM), design indicators for variety are identified and ranked. Also, the DFV approach is simultaneously modeled with the categories of design for cost (DFC) and design for supply chain (DFSC) and a mathematical model applied to the development of the product platform architecture is obtained, which seeks to diversify the product and reduce costs and Supply chain process management. The case study of the current research is the phased array antenna system, in which the problem is solved using one of the new optimization techniques (LP metric) and GAMS software. After the implementation of the model, its validation was carried out and considering three objectives including the total cost and the evaluation score (competence) of the suppliers and the objective of variety and the seven main parameters of the model, sensitivity analysis and other comparisons and results. A review is provided. Regarding the comparison of the goals with each other, the findings show the inverse relationship of the total cost goal with the variety and the evaluation score goals and the direct relationship between the two variety and the evaluation score goals. Also, the results of the sensitivity analysis showed the higher effectiveness of the goal of variety among the investigated parameters, and the evaluation score (competence) of suppliers and the total cost were ranked next.

Abstract Human reliability is an important issue that is evaluated in order to prevent catastrophic events in high technology industries. The purpose of this study was to evaluate human reliability by CREAM fuzzy method in short and medium range radar systems, which ultimately led to the study of human reliability and the probability of error in each of the effective factors. Then the method of hierarchical analysis, pairwise comparisons, calculation of weights and system compatibility, matrix of pairwise comparisons and control style, and ranking were performed. After collecting information from questionnaires and consulting experts, job analysis was performed by hierarchical analysis (HTA). Then the table of working conditions affecting the operator's performance (CPC) was drawn, and working conditions affecting the user's performance were presented using the table of CPCs. In the next step, the fuzzy AHP method was investigated , after calculating the pairwise comparison matrices, control styles were determined. At the end of the work, the factors causing the error along with the amount of human reliability and the probability of error in each factor were identified. The results indicated that human reliability is significantly improved. Based on the findings of the study, determining the contribution of various factors influencing human error, provide a more effective assessment. Among the job tasks, the factor of "preparation of mechanical parts" with a probability of 0.416 has the highest probability of error and should focus more on this factor.

Abstract Expanding product variety helps customers to find products that perfectly fit their individual needs. Therefore, companies are looking for ways to better manage and variety procedures in the product and a design that is compatible with variety can be considered a competitive advantage for the organization. The present study aims to evaluate engineering designs with a variety approach, has presented an optimization model that examines engineering designs in terms of two parameters, the amount of changes required by the design to standardize now and future manufacturers' efforts to redesign the components. The parameter of the amount of changes required by the design for standardization now is obtained with the help of the generational variety index and the coupling index and the parameter of future manufacturers' efforts to redesign the components with the help of the commonality index. Applying the model developed in the present study, as well as determining the allowable components in the standardization priority and the amount of effort in the future will lead to the selection of engineering design that can reduce the cost of product development, redesign efforts and market time. The model is developed in the present study has been implemented on one of the fuzzy array radars of Iran's electronics industry and has determined the optimal engineering design of the desired radar.

Abstract Today hidden costs and quality opportunities cost are two parameters not seriously considered in most organizations.in today's competitive world, loss of customers imposes important and significant costs on the organizations. therefor  in this study, in order to reduce the cost of total quality we present a method to calculate the cost of damage to customers ' goodwill and the cost of damage to the organization brand .In working out the cost of damage to the goodwill of customers, first the quality requirements as well as the weight assigned to each requirement is calculated. Having figured out the costs related to the discontented customers, we have embarked on finding out the loss rate damage to the customers' good faith and eventually the cost of damage to the customers' good will. In calculating the damage costs to the organization's brand, from among available models, the Acker model has been utilized which serves our purpose. Following the procedures given in the latter model, the parameters generating costs are identified and then the damage costs to the organization's brand is worked out. finally, the findings indicate that dissatisfied customers inflict the most damage on the organization. Finally, the methods and procedures suggested in the current research are implemented in a selected industry. The obtained results in the industry referred to were endorsed both by the industry's elite experts and academic authorities.
 

Abstract design to cost (DTC) utilized at concept phase design is branch of design for Xwhich by exploiting different techniques and procedures, estimates the life cycle costs of different design for product before its manufacturing: thus, enabling producer-by comparing costs revenues, and profits-to select the most optimal design for manufacturing a product. The present research sets out to execute and deploy DTC method for specific electro-optical product. Unlike other research works, the present study has availed itself of the axiomatic design method to analyze customers' needs and converting them to estimating life cycle costs-by examining different models in light of available costs and information. Structure in the industry under investigation –we have developed an estimation model base and developing mathematical formulas, we have embarked on calculating life cycle costs of two design A and B .the obtained results indicate that in the care of product under study, design A – as regards cost effectiveness in production and life cycle costs in economic terms- can be selected as e premium concepts design. 
 
  

Abstract  In this research, in order to allocate reliability to the subsystems of a cube satellite in the conceptual design phase-with the objective of achieving a 73% reliability-we have developed. The target feasibility method as our research fundamental procedure. In no research study in the area of reliability allocation conducted so far have we found a method which has developed the technology factor or considered the relationships between suppliers and the issue of reliability allocation.  Therefore, the current research study focuses on the exact calculations of the technology factor. In order to estimate the letter factor, a concept designated as technology preparation assessment and another one as level of suppliers technological capacities are being discussed. In this regard, a model has been presented which is a synthesis of the letter two concepts.  The obtained results indicate that the reliability allocation through by adopting this methodology is a great help toward identifying critical subsystems and heir improvement at the design stage . 
 
  

Abstract Many engineers and researchers base their reliability models on the hypothesis that the components of a system work statistically independently and fail. This assumption is often violated in practice because, specific environmental and systemic factors affect the performance of components and thus contribute to correlated failures, which can reduce the reliability of a system. Determining the component correlation index and its effect on system reliability is necessary to be able to require models to explicitly combine and coordinate continuous failures and provide an accurate estimate of system reliability. Previous approaches to correlation modeling are limited to systems that consist of two or three components or assume that the operation of the components is statistically independent. In this study, while considering the dependence between component functions, a model is presented to consider this dependence and calculate the reliability of series, parallel, k-out of-n, parallel-series and series-parallel systems. To better understand the problem, examples are provided with sensitivity analysis in which the components are functionally interdependent. These examples show how the correlation between the components has affected their performance.

Abstract  Success in supply chain implementation depends on how it operates in the face of market changes and customer needs. Agility is a concept recently introduced by supply chain researchers to better design supply chains. Accordingly, and considering the importance of the topic. In this research, the design of Multi-objective closed-loop supply chain network is discussed. Accordingly, and considering the importance of the subject, in this research, the design of Multiobjective closed-loop supply chain network is discussed. The main innovation of this research is the integration of green and agile concepts in supply chain design. To this purpose, a mathematical model with economic, environmental and agility objectives is presented. In order to solve this mathematical model, two methods of Epsilon constraint and Multi-objective weed optimization are proposed. The results of the comparisons between the two methods show that the weed algorithm performs well in terms of different Pareto boundary quality and dispersion indices. At the end, the results are presented for a case study of the Dalan Kuh dairy supply chain and the Pareto border is described. 
 
 

Abstract Today, the defense of sensitive areas and resources is a fundamental issue that encompasses all key infrastructures, and to achieve the goal of reducing the damage and injuries caused by the attacker, the use of informed and useful strategies is necessary. In this research, modeling is considered to optimize the protection of investment systems that have a series-parallel reliability structure and have a functional correlation with each other. In general, in this study, first considering the functional independence of subsystems, the probabilities of a successful attack, the system reliability structure and the game theory approach to finding the equilibrium point, a nonlinear programming model is proposed to determine the investment defense of systems. Then, by determining the reliability relationships despite the functional correlation between the subsystems, a linear programming model is introduced to determine the correlation coefficient of the subsystems and to redistribute investment to defend the systems. Finally, the proposed research model is used for a numerical example and the results are analyzed.

Abstract Reliability and safety of any system is the most important quality characteristic of a system. This qualitative characteristic is of special importance in systems whose operation is under various stresses such as: high temperature, high speed, high pressure, etc. A noteworthy point that is often not taken into account in calculating the reliability and safety of systems is the existence of interdependencies between subsystems with each other, which causes different failures in the system. One of the most important of these failures is common cause failure. In this type of failure, several subsystems or all subsystems fail simultaneously or in a short period of time due to a common cause. Failure to consider common cause failures in calculating the reliability of systems leads to an optimistic estimate of the reliability rate of the system and consequently leads to overconfidence in the system. In this paper, first using the product structure separation techniques (PBS), performance flow block diagram (FFBD) to identify and then using the reliability block diagram (RBD) to calculate and allocate the output reliability of a dynamic positioning system that includes hydraulic thrusters And electric for the movements of roll, suge, sui, yaw and hyo, will be discussed.In calculating the reliability of the system with the help of cascade failure probability rules and with the help of beta factor model and PDS method, common cause failures of different subsystems were considered.

Abstract The current trend in various industries acknowledges that establishing a system with the ability to quickly refer to the level of product failures or estimate its reliability is a necessity for every industry. Reliability is doubly important in military industries. One of the products of the military industries is anti-aircraft shells that are used against enemy threats, and the failure or failure to act on time of this product can cause irreparable damage, which increases the importance of this product. In this case, it is in the design stage and there is no previous or experimental data available, the lack of data is considered the main problem, and to solve this problem, we use Bayesian networks, and due to the lack of knowledge of the reliability of components in the design stage and the lack of sufficient and accurate knowledge of experts about the reliability of components, a basis is considered for the reliability of each member, and fuzzy theory is used to obtain reliability. To obtain reliability using fuzzy Bayesian networks, we first draw the product fault tree and by converting the fault tree into Bayesian networks, the product reliability is estimated.