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This paper presents a new decentralized/distributed decision-making (DDM) supply chain planning model. A supply chain is called decentralized when various decisions are made in different companies trying to optimize their own objectives. The proposed approach is applied to plan a wood supply chain network called Puya Wood Company. The supply chain network design problem discussed in this paper is an integrated multi-echelon, multi-product problem considering total costs of purchasing raw materials/returned product, transportation of raw materials, and inventory holding of raw materials. A coordination mechanism is designed to share information between the retailer model and the manufacturer model called centralized planning. The main contributions of this paper are summarized as follows: (1) presenting a decentralized (distributed) approach in order to address the production and distribution problem in supply chain including manufacturer and retailers and (2) proposing a coordination mechanism in order to handle problems related to production and distribution in a two-echelon supply chain network through a decentralized approach. The proposed model is tested using real case study. Sensitivity analysis is accomplished to find the effects of changing the parameter on the results. The proposed coordination mechanism provides high-quality solutions in reasonable number of iterations for the case study. This coordination mechanism can be applied in other supply chains such as natural gas and oil, water resource management, and crisis and disaster planning. [ABSTRACT FROM AUTHOR]

Three-dimensional printing (3DP) is an evolutionary solution for making customize items for all sectors, but it has become more prominent in the healthcare sector. In this field, some solutions have to be adapted to patients. This is especially true for dentistry, where all the patients have their own unique mouth and tooth structure. It is now possible to provide an accurate model of the patient's mouth and teeth with solutions that are perfectly compatible with them, leading to the provision of a dental service with a high success rate. Even if there is a problem, it is enough to change the three-dimensional design. Therefore, it is a time-saving method, too. The purpose of this study is to investigate the role of 3DP in dentistry and to identify the processes and procedures resulting from the use of this technology. To do so, with the help of a case study, a 3DP-based dental clinic that provides implant, orthodontics, restoration and dentures services is simulated in Arena software. The current state of the system is assessed by defining appropriate evaluation criteria including net profit, utilization, waiting time, patients makespan and laboratory makespan. The simulation model is then developed with innovations such as adding an inventory control policy, creating rest time for resources and controlling the policy of sending products from laboratory to the clinic. After an extensive sensitivity analysis, improving the performance of the system is on the agenda of this paper by examining various scenarios. Results show that scenarios such as reducing some resources of the system or considering rest time in exchange for increasing the duration of the work shift can have a significant impact on clinic performance. [ABSTRACT FROM AUTHOR]