Designing multi period-multi level Supply Chain for Fixed Lifetime Perishable Products under Uncertainty

The current research has considered the design of the four-level supply chain of perishable goods, including manufacturing factories, distribution centers, wholesalers, and retailers, in conditions of uncertainty in important parameters. The aim is to make strategic and tactical decisions, including the location, number, and size of distribution centers and wholesalers, stock levels in stocking centers, determining the flow of goods between facilities at different supply chain levels, and choosing the type of means of transporting goods between facilities. This is achieved through a three-objective mathematical model. The goals include minimizing the expected total cost in the supply chain, achieving the shortest travel time of goods in the chain, and at the same time minimizing the amount of deviation from customer demand. The presented model tries to pay attention to environmental uncertainty and consider different operational scenarios, as well as the possible approach in important parameters. This takes into account the product life cycle, the different rate of spoilage of the goods in different storage facilities, the different capacity of the facilities in different scenarios, and considering different methods of product transportation with different rates of product spoilage. All of this aims to cover the lack of previous research in the field of perishable goods supply chain design. Considering the multi-objective nature of the model and the need to create flexibility in decision-making for decision-makers, this research uses Normal Boundary Intersection (NBI), which allows decision-makers to choose the most optimal solution according to the importance of different goals. GAMS 24 software and MILP solver were used to solve the mathematical model. Materials and Methods This study presents a multiobjective model for designing a four-echelon supply chain (SC) in the strategic and tactical levels for fixed lifetime perishable products. The targeted SC levels include production plants, distribution centers (DC), wholesalers, and retailers. The locations of the plants and retailers are predetermined, while the locations of DCs and wholesalers will be selected from potential locations. The elaborated model seeks to minimize the total cost and product transportation time in the SC and minimize expected demand deviation as well. The Normal Boundary Intersection (NBI) method is employed for solving the model, and GAMS software is used to determine the optimal values of decision variables. Results This study utilizes a case study of an Iranian broad dairy company that produces eleven product groups. Data for the study were collected from historical company records and expert interviews. According to the opinions of the experts, three different operational scenarios have been extracted, and the data related to each scenario, especially the customer demand, has been estimated according to historical data as well as the corrective opinions of the managers. The results of the proposed mathematical programming model showed that changes in demand did not have unexpected effects on the values of the objective function and did not change the general trend of the answer to the problem. On the other hand, changes in the percentage of perishability of the product had far less impact on the values of the objective functions as well as the membership function. The overall result is normal, and as a result, in general, these changes represent the stability of the model against the fluctuations of important parameters. A comparison of optimal results and reality reveals that the examined SC needs a redesign of its DCs and wholesalers' locations, and hybrid transportation methods should be used. Conclusion Supply chain design (SCD) of fixed lifetime perishable products at the strategic and tactical levels is indeed an important issue. By considering the research gap, this study developed a multi-objective and multi-level model for SCD of fixed lifetime perishable products, and new concepts such as varying perishability rates in storage and transportation facilities are considered. On the other hand, with regard to environmental uncertainty, important parameters such as demand and capacity of facilities are considered as probable parameters. Adding environmental and social factors as new objectives, hybrid transportation methods, and horizontal interactions in the same SC levels can be considered for model development. In order to solve the proposed model, NBI has been used, which has significant advantages compared to other solution methods. By turning the answer of the optimization model into a kind of decision-making problem, this technique gives flexibility to the decision-maker to choose the best solution for their supply chain design according to the weight of each goal. Also, the decision-maker can redesign and increase the adaptability of the supply chain by changing the important parameters of the problem over time

Presenting a circular supply chain optimization model under uncertainty: the case of MDF industry

The circular supply chain includes return processes and additional value intends to reduce the waste of resources and improve the efficiency, it plays an important role in reducing costs and increasing the level of sustainability of supply chains. Therefore, in the current research, a multi-objective, multi-level circular supply chain optimization model was presented in in uncertain conditions, which minimizes system costs and environmental impact and maximizes social responsibility. In order to face the uncertainty in demand, a scenario-based approach has been used. Then, the multi-objective model was converted into a single-objective model using the enhanced epsilon constraint method and solved with Gams software. The data of an active company in the MDF industry has been used to examine the application of the proposed model. The results of sensitivity analysis carried out on some important parameters showed that paying attention to the maximum number allowed for the establishment of collection and recycling centers has a significant impact on the costs and environmental effects in the system

Using fuzzy Choquet Integral operator for supplier selection with environmental considerations

The increasing importance of considering environmental issues as a part of the corporate social responsibility, which has environmental and social impacts as well as affects the image and competitiveness of a firm, has encouraged companies to revise their major processes of supply chain management (SCM). Since the performance of a company heavily relies on its suppliers, it is of vital importance to incorporate environmental criteria into supplier selection problem to satisfy both conventional and environmental criteria, which have only been considered by a limited number of studies. Therefore, following a brief review of green supply chain management (GSCM) and sustainable supply chain management (SSCM) concepts and investigation of supplier selection approaches, this study after focuses on a modified Delphi method that has been applied to determine supplier selection criteria. Also, the intuitionistic fuzzy value (IFV) and interval value intuitionistic fuzzy (IVIF) have been utilised for supplier evaluation regarding the subjective nature and uncertainty of judgment. By using the Choquet Integral operator and fuzzy measures, the best supplier has been selected, and the comparison between IFV and IVIF has been made. This methodology has been applied to a manufacturing company to assess the applicability of the proposed methodology. The proposed methodology can be used for real world problems that contain fuzziness or interacting decision criteria. Moreover, due to a high level of expert involvement in the decision-making process, we claimed that the knowledge of experts has been utilised constructively

A study in the field of automobile industry's production control system

هدف این مقاله بررسی وضعیت سیستم کنترل تولید در صنعت خودروسازی ایران است. سیستم کنترل تولید در استفاده مناسب از امکانات هم خود معنای بهره وری را به ذهن متبادر می نماید. چنین بررسی ای می تواند به عنوان گام ابتدایی در جهت شناخت و استقرار سیستم کارآمدتر و یا بهبود بخشیدن سیستم فعلی محسوب گردد. هم چنین نه تنها به شناخت عوامل درون سیستمی کمک می نماید بلکه برخی از عوامل جانبی این زمینه را نیز معرفی می نماید. در واقع این نوشته گزارشی است از پژوهشی که در زمینه شناخت سیستم کنترل تولید در شرکت های خودرو سازی ایران توسط نویسنده انجام گرفته است و بر آن است تا با استفاده از یافته های پژوهش تصویری از سیستم کنترل تولید در صنعت خودرو سازی ایران و محیط آن ارائه کند

Timely research on the application of the production system in the automotive industry of Iran

سیستم تولید به موقع هم اکنون مورد توجه بسیاری از شرکت های کشورهای صنعتی و کشورهای تازه توسعه یافته قرار گرفته است. آیا برای واحدهای صنعتی ایران نیز امکان به کارگیری آن وجود دارد. تلاش کوچکی در این زمینه با نظر خواهی از تعدادی از مدیران انجام گرفت که این مقاله با توجه به نتایج آن تنظیم شده است اگر چه نمی توان سیستمی را به طور کامل در محیطی با شرایط متفاوت پیاده نمود ولی رد و بدل کردن ایده ها بدون سعی در تکرار کامل همه ی جزییات می تواند برای صنایع مفید باشد

INTERVAL TYPE-2 FUZZY DYNAMIC NETWORK DATA ENVELOPMENT ANALYSIS WITH UNDESIRABLE OUTPUTS CONSIDERING DOUBLE FRONTIERS: AN APPLICATION TO IRAN AIRPORTS’ SUSTAINABILITY EVALUATION

The sustainable airports play irrefutable role in making transportation systems sustainable. One of the approaches that can be used for evaluating airports’ sustainability is fuzzy data envelopment analysis (DEA). Fuzzy DEA methods have been introduced to cope with fuzziness of variables. However, it is noteworthy that fuzzy DEA is still restricted to fuzzy variables, while some of these variables are affected by uncertainty and also information granularity. Interval type-2 fuzzy sets which have characteristics of type-2 fuzzy sets and do not add any complexity to the calculation process can be applied to deal with such a problem. That is why in this paper, it is explored that how an extension of fuzzy dynamic network DEA approach based on double production frontiers helps to measure airports’ sustainability. Such an integrative approach in DEA approach is unprecedented. So, this extension of DEA is valuable from both technical and conceptual aspects.

Make or buy decision considering uncertainty based on fuzzy logic using simulation and multiple criteria decision making

Decision making on making/buying problem has always been a challenge to decision makers. In this paper a methodology has been proposed to resolve this challenge. This methodology is capable of evaluating making/buying decision making under uncertainty. For uncertainty, the fuzzy logic and simulation approaches have been used. The proposed methodology can be applied to parts with multi stage manufacturing processes and different suppliers. Therefore this methodology provides a scale for decision making from full outsourcing to full manufacturing and with selecting appropriate supplier

Application of Value Engineering in Service Project Management

The prime objectives of Project Management are to minimize time and cost and to meet required performance. Value Engineering is an organized effort to attain optimum value in a system by providing the necessary functions to improve performance at the lowest cost. Value Engineering can contribute to the field of project management to achieve its objectives. This paper explains a model of service project management with the aid of value Engineering

Agility, a Modern Narrative of Old Concepts

Agile manufacturing as the most modern production system has covered significant portion of literature in operations management. But there is a great vague. whether agile manufacturing is the same as prior concepts but in a new form or it's a completely new concept accompanied with necessary techniques? Lean production and Agile production are two dominant production systems that were studied through literature survey and their dimensions were defined. Then dimensions similarities and differences among these two approaches were investigated. Finally considering the importance of different dimensions, weighted difference between them is demonstrated. Results show that although there are some common features between these two concepts, their emphasis on different aspects has formed a new approach. The proper attention of agile system to nowadays business requirements and continuous change, has distinguished it from other production systems such as lean production system