Journal of Quality Engineering and Management

Abstract The reliability assessment of multi-state systems is often investigated by assuming the independence of the components. It is very useful to consider the interactions between components to evaluate the reliability of such systems. The traditional block diagrams do not evaluate the reliability of a repairable multi-state system. The use of simple stochastic process methods is very difficult due to the high dimension of the problem (the very large number of system states) for engineering applications. To the best of our knowledge, the universal generating function has not been used for systems with dependent components. In this paper, using stochastic processes and a universal generating function method, multi-system systems are analyzed in a situation in which the performance distributions of some components depend on the state of others.

Abstract Guarantee costs in production companies are very important and can have a great impact on the profit of the company. Putting effort into reducing these costs may result in profit increase. In this regard, detecting reliability related defects before their occurrence can be useful in reducing guarantee costs and also customer dissatisfaction. Reliability problems may be due to manufacturing defects. Removing defective items during production process can prevent high guarantee and customer dissatisfaction costs. In this paper a model is developed for early detection of reliability defects by means of guarantee data and qualitative parameters of the production line. A case study on TU5 engines manufactured by Irankhodro Company is also included.

Abstract Nowadays, the integration of the supply chain has changed into an obligation due to the global competition and the necessity of quick response. Therefore, identifying and ranking the vulnerabilities of the integrated supply chain is of great importance and ignoring and even incomplete execution of this process may do irreparable damage to different sections of the chain. The present research aims to analyze the interaction among the vulnerabilities of the supply chain and setting their priorities. F.DEMATEL is used to examine the factors and F.ANP is used to rank the factors. The results show that the environmental and communication factors have the greatest effect on the vulnerability of the integrated supply chain. The production factor has the greatest rank among the factors to be affected. Also, the results showed that it is possible to reduce the vulnerability of the supply chain considerably and provide the causes of the improvement in production through creating communication networks over the chain and enhancing the indices such as improvement in dispersion and the weak harmony of the supply chain partners and transparency of the information over the supply chain. The results of the present research help the managers considerably to identify the difference of the vulnerable internal and external vulnerabilities of the supply chain and to identify the improvement priorities.

Abstract   The objective of this research is to provide a rich picture of current issues of the company and a conceptual model along the seven steps of SSM model in the field of quality management. Soft system methodology is a tool based on the philosophy of soft operational research that has been used to formulate and manage complex problems. Investigating the effect of this technique is a significant contribution to continuous improvement in competitive environments. Therefore, the present study attempts to implement this model in one of the food industries. It seems that the use of soft operational research techniques along with other tools and approaches of total quality management, in organizations that consider quality as an important and strategic issue, help practitioners in this field. The findings indicate that in the studied company strategy formulation is not well-performed according to the company vision. Also, the inappropriate cooperation and involvement of the staff in formulating the strategies, inappropriate support of staff innovation as well as the inappropriate rewards system, lack of effective communication with the customers and partners, changes in the foreign currency, and the problems of refining with the suppliers and contractors are among the issues in the studied company.

Abstract The real world energy sector is one of the most sophisticated systems that must be viewed in a holistic view. In this research, researchers have identified and analyzed the effective interactions of after-sales services in the Iranian LPG industry. Since post-sales services can be assessed on a variety of criteria, the Multi-criteria Decision Approach (MCDM) approach for such an analysis is a good approach. Due to the particular complexity of the liquid gas industry from the refinery to the end user's end, in this research, DEMATEL FUZZY is used to analyze internal interactions, and for the reader to have a deeper understanding of the subject, the causal diagrams (CLD) in the form of Dynamic Systems (DYNAMIC SYSTEM). After thorough review of the theoretical foundations and expertise, 17 industry-leading indicators of the post-sales service have been identified in this industry and 10 respondents have answered questions. In addition, the researchers express specific definitions of service in this industry. The results of the research show that reliability variables, representations, documents have the most impact, and improvement variables, responsiveness, timing of visits have the greatest interaction with other components in the model. Dynamic model also depicts the real world image of internal service interactions.

Abstract In order to improve productivity, Article 5 of the Sixth Development Plan Law mandates the implementation of the productivity management cycle, which states that "executive bodies and the armed forces are obliged to focus on productivity growth in the economy, while implementing the productivity management cycle in the complex." "Provide
the necessary arrangements for the operation of this cycle in the units under its auspices in
coordination with the National Productivity Organization of Iran and submit its annual report to the National Productivity Organization." It is also stated in the program that from the projected 8% economic growth, 2.8%, ie equivalent to 35% growth, should be obtained from the total factor productivity.
There are several models for measuring productivity, among which the model with financial ratios approach has been used in this paper. There are also various methods for measuring productivity. In this paper, the value-added method is used to calculate partial and total productivity indices in Method Company. Two financial statements, balance sheet and profit and loss statement in the period of 1391 to 1395 as input data as well as standard worksheets of the Productivity Center of Iran to measure productivity indicators are entered into a software designed to output Those productivity ratios and related graphs are similar in the method company and in the industry. Multiple regression was used to select the appropriate approach to improve productivity and show the effect of independent variables (partial productivity indices) on the dependent variable (total productivity), followed by material productivity as the first priority and productivity. Manpower, energy and capital were identified as the next priorities for improvement in Method Company.