نشریه پژوهش در مهندسی نگهداشت دفاعی
پیاپی 3 (بهار و تابستان 1399)

Point machine is one of the key equipments in the railway industry that the reliable performance of this electromechanical equipment plays a key role in increasing the level of performance safety and operational continuity. In this study, the method of reliability centered maintenance(RCM) was used to develop maintenance and repair programs for point machines. Equipment manufacturers instructions or experiences of repair teams, regardless of the patterns and consequences of failure, or even the correct identification of the causes of failure, is often the basis for developing maintenance plans and preparing preventive repair checklists in urban train complexes. In this research, an attempt has been made to investigate and show the difference between maintenance programs in traditional methods, with structured and logical methods such as reliability centered maintenance techniques. The results of this applied research show that the application of reliability centered maintenance analysis for point machine leads to increasing the effectiveness and efficiency of maintenance and repair activities, as well as reducing the cost and amount of repair activities. In the present study, the field method (interviews with experts in operation, maintenance and repair of point machine in urban train complexes and review of operations and repair offices) has been used to collect relevant data. The technical managers of urban train complexes can use the results of this research to modify the contract of maintenance and repair contractors and to develop the use of reliability centered maintenance techniques at the level of urban train complexes.

One of the problems that defense logistics oriented organizations had always faced is the cost for transportation sector of logistics systems. Among the concerns of a logistics organization is that the all required parameters of problem for decision making is not known and it has caused that Supply chain network design under uncertainty be one of the issues that attracts a lot of attentions. In this paper a closed-loop supply chain network is designed and demand and average disposal fraction parameters are under uncertainty. The research was carried out at the Abuzar branch of the Ghadir self-sufficiency organization, which works in the field of machinery maintenance. In the mentioned supply chain network, customer demand for machinery maintenance and average disposal fraction are not always known in advance. In the following it is used from robust optimization approach to cope with parameters uncertainty in this network. The mathematical model of this paper is mixed integer linear programming. The objective function of this model minimizes total logistics costs in the defense organization. After solving the model, numerical results presented to senior managers of the defense organization. Numerical results represent the performance of the proposed model.

In this study, a high-capacity UPS device in the country's military industry, which has been in operation since 2003 and has had significant problems due to increased depreciation and performance has been selected. The reason for this choice was the high sensitivity in the maintenance of military electronic equipment and increase the reliability of such equipment in times of need. After holding brainstorming sessions and reviewing various scenarios by the organization's experts, two final options were finalized: a) Using the current UPS device and performing major repairs if possible. B) Buy a new UPS device with the latest technology and replace it with the current device. To select one of the above options, the Life Cycle Costing (LCC) method has been used to determine a better option from an economic perspective. After reviewing and calculating the investment costs and maintaining both options, the results of the study showed that the annual uniform cost (EUAC) of using the current UPS device is more than the uniform annual cost of replacing and purchasing a new UPS device. It is out of service of the current system.

The present study reviews existing recent literature to integrate lean thinking and sustainable development in the field of safety, health and environment (HSE) in construction industry. Then objectives, tools, indicators and concepts interaction are studied. Therefore, the purpose of this study is to review of latest ISI articles published in prestigious international journals in English and some Persian search-engines in order to obtain reach and update literature, fill the gap and improve the functional level of safety, health and environment In the country.
Construction operations have many direct and indirect effects on the environment. With the growth of economy and population, necessity of designing projects that adhere to the principles of lean construction and sustainable development to protect the environment and the executive factors of projects throughout the construction life cycle is felt. Sustainable Development (SD) seeks to improve the performance of industry by increasing economic, social and environmental values ​​and interacts with lean thinking (LT), especially to ensure community health. Although the major correlation between lean and sustainable indicators has been proven in recent studies, recognition of lean and sustainability in HSE plan, needs further explore. The result of this study is development of literature and helping to clarify the perspective of construction factors, diagnosis and analysis of variables and indicators of the three pillars of research by providing an integrated model.

The multi-objective optimization issue is the main objective of creating optimal set of objectives known as Pareto optimal front in order to provide the ultimate decision-maker.
The last determination of a point of Pareto front in order to actualize the framework by the decision maker, generally just done dependent on the objectives introduced in the mathematical model. In addition to these objectives, it is better to consider other criteria to select the final answer. One of the most important criteria, the manufacturing firm response to changes in the parameters of the problem. In this paper, a mathematical model for the design of production cells by taking two non-contiguous objectives between cellular components, presentation and analysis. Cooperation between workers in a cell can have a large impact at the time of completion. So one of the important points in the cell production system, control all system components during the manufacturing process. This means that the number of workers, machinery and parts devoted to the cells must be at a manageable level. To analyze and evaluate the stability of the solution produced a solid analysis techniques using Monte Carlo simulation has been used. This method increases the quality of the final stages to be chosen by the decision maker.

With the expansion of industries and companies, the number and dimensions of buildings and facilities of organizations are increasing, which increases the value of these assets, increasing the importance of maintenance and repairs of these facilities. On the other hand, as the number of assets increases, the process of managing their maintenance and repairs becomes more difficult than in the past. It is better to define a model for scheduling the maintenance, to proposed the optimal time and order of maintenance program. In this paper, by the combination of Genetic algorithm (GA) and Particle Swarm Optimizations (PSO), a new model for scheduling maintenance for organizations with different locations is presented. The main contributions of this paper are (a) Definition of the main problem in multiple locations and consideration of travel times between each location. (b) Consideration of different work skills for maintenance plan. (c) Consideration of the possibility of outsourcing each task. Considering 10 scenarios for the number of facilities, 3 scenarios for the number of specialists in each location and 2 scenarios for the type of costs, the results show the better performance of the proposed model in compare of three different models as Gulpiras model, Koay’s Model, and Javanmard’s model, where the results have been shown, by using the proposed model, it is possible to reduce costs just over by 34%.