Dissertation to receive Master's degree (M.A)
Field: Industrial Management (Production Orientation)
Summer 90
Abstract
With the current development of industries, return and reuse of used products has become one of the important logistics activities of manufacturing industries. This has led to the creation of laws in this field, as well as increasing awareness among people in order to preserve the environment and reduce waste.
According to the specialized needs to perform logistics activities and the widening of the scope of activities in manufacturing industries, industries tend to turn to third-party reverse logistics suppliers - who specialize in logistics activities. Therefore, the selection of the reverse logistics supplier and the influencing factors in this selection and the structure of the influencing factors in the selection of these suppliers are considered important issues in the manufacturing industries.
In this research, using the DEMATEL method Relationships of factors influencing the choice of reverse logistics supplier were analyzed And by using the VIKOR method in the fuzzy environment, the third party reverse logistics suppliers have been ranked. It should be noted that the VIKOR method is one of the multi-criteria decision-making methods that focuses on ranking and choosing a set of options and determining a compromise solution for a problem with conflicting criteria. In this research, a fuzzy approach is proposed for the VIKOR method, where the ranking of the options and the importance weights of the criteria are done as fuzzy numbers derived from the verbal variables. Chapter 1: Overview of the research: Introduction: Reverse logistics[1] means the process of proper movement and transfer of consumed and unused items from the last destination to be distributed to gain the value of the products in the eyes of the customer or their proper consumption (Alam Tabriz, 2018).
The efficient implementation of reverse logistics requires that a logistics network Suitable for performing reverse supply chain activities [2] such as collection, inspection, warehousing, separation, recycling, remanufacturing, repair and so on. be created Therefore, many industries nowadays have a great desire to outsource their reverse logistics service[3].
One of the advantages of this is that the organization's logistics costs are greatly reduced in this way. Also, by outsourcing its reverse logistics, the organization can enter new businesses and markets instead of carrying out logistics activities (Kanan [4], 2009).
When organizations decide to outsource reverse logistics, they must answer the basic question: Is there an efficient third-party reverse logistics provider (3PRLP[5]) for the required logistics network? Choose a suitable supplier from among the options. In this regard, various activities have been carried out. In this research, an attempt has been made to provide a model for choosing a reverse logistics supplier, to help organizations to make the right decision according to various aspects in this selection. 1.1. 1.1. Statement of the problem
Reverse logistics is the process of collecting and transporting returned goods and how to properly deal with these types of items and perform all operations related to the reuse of goods and materials in order to increase the productivity, profitability and efficiency of the organization. This requires the identification of needs, obtaining information, demands, plans and steps that flow from the customer to the manufacturers and suppliers. Reverse logistics requires close cooperation of production units, marketing, finance and information systems in human resources. This is because of the occurrence of conflicts and inconsistencies Avoid as much as possible. Therefore, the correct selection of a supplier in reverse logistics can reduce or eliminate a large part of the problems in this field.
The issue that is raised here is how an organization can choose one of the suppliers that exist in this field as the selected supplier?
Each of the suppliers has indicators that can be mentioned among the following:
Quality [6] (product performance, product accuracy, awareness) Supplier quality.)
Distribution [7] (meaning the ability of the supplier to perform the task according to the distribution schedule, flexibility and reliability of distribution)
Reverse logistics cost[8] (Cost of inventory review, transportation, packaging, etc.)
Technical and engineering capacity[9] (Having skilled manpower, capacity to create reverse logistics, etc.)
Choosing the best reverse logistics supplier Using the opinions of experts And it is done by the group of decision makers[10] by examining the aforementioned factors. Some of these indicators are described by linguistic variables, which must be converted into small values, which is done through weighting in the fuzzy environment. Using the theory of fuzzy sets [11] can be useful in working with human uncertainties and commenting on decisions. Here, it should be noted that the weight of the indicators should be examined in two ways. One is the absolute weight and the other is the weight caused by the influence of the indicators on each other. In any case, the selection process with Determining the appropriate criteria begins by determining the relationships between them.
In this research, first, the criteria that are necessary for the selection of 3 PRLPs are determined, and after weighting the indicators, the organization must decide on the supplier selection. Considering that the choice may be made in ambiguous and uncertain conditions, therefore, the model is implemented in the fuzzy space. Also, the structure of relationships between indicators is determined using the fuzzy DEMATEL[12] method and the reverse logistics supplier is selected using the fuzzy VIKOR method.
1.2. Importance and necessity of research
Nowadays, the management of logistics functions in modern organizations and organizations can be called decision-making about the complete distribution of the company's goods and services. On the other hand, what is important in management is maximizing the added value of goods and services and reducing company costs. Therefore, companies tend to use the services of reverse logistics providers. Among the reasons for outsourcing reverse logistics activities, the following can be mentioned:
Third-party reverse logistics supplier companies (3PRLP) have advanced information systems, tool transportation capabilities, material handling equipment, and storage facilities to provide complete reverse supply chain services.
Reverse logistics cannot be the core of a company's activities, and as a result of these secondary and secondary activities, the main tasks of the organization may not be performed well. By outsourcing reverse logistics, companies can focus on their main activities.
Outsourcing reverse logistics activities can reduce costs. A 3PRLP can provide the company with economic advantages that the company cannot achieve in other ways.
By outsourcing reverse logistics activities, companies can reduce the initial capital for the company and expand investment for production activities.
Reverse logistics outsourcing improves cycle time and performance, thereby increasing customer satisfaction in the sales market.
Evaluation and selection of a logistics supplier. Reverse, since it includes different and complex criteria and decision-making models, is a sensitive and difficult matter.
In this field, various activities have been carried out and in few works, multi-criteria decision-making models have been used. This has often been done assuming deterministic conditions. Therefore, it seems necessary that the problem should be investigated in the conditions of uncertainty (fuzzy space) and based on multi-criteria decision making models[13].
1.3. Research objectives
Reverse logistics suppliers have become one of the important roles in reverse logistics. Since the return of goods has required information, equipment and specialized economic infrastructure, the industry has turned to reverse logistics suppliers.
Due to limited resources, many companies do not have the capacity or desire to enter the field of reverse logistics. Therefore, they leave all or part of the reverse logistics activities to the suppliers. Due to the fact that there are various criteria in the selection, choosing a supplier becomes a complicated task. Companies use different ways to deal with this issue. The most important issue in the process of choosing a reverse logistics supplier is choosing and using a suitable decision-making model.