Dissertation for Master's Degree
Industrial Engineering Department, Industry-Industry Orientation
March 90
Abstract
Today, due to the progress in technology, the globalization of markets, the diversity of customer demands and increased competition, organizations need to improve their internal processes in order to survive. Satisfying customers at the same time as managing the final cost has prompted organizations to interact more with their suppliers and monitor the quality of production of primary parts. In addition, in a situation where buyers only think about their own interests, they cannot expect long-term and growing relationships with suppliers. Therefore, the need to pay attention to the interests of all members of the supply chain and focus on a win-win policy for organizations and suppliers is felt more than ever.
In this research, a situation is considered where a buyer intends to supply a part from several suppliers, but considering that a percentage of the received items are always defective and accepting or rejecting them affects the long-term relationship between the supplier and the buyer, making a decision It is particularly important in this regard. In this research, several different decision-making methods regarding defective items are introduced and modeling is done based on different ways of dealing with these defective items, which will ultimately lead to choosing the best decision-making method with these defective items.
Key words:
supplier selection, coordination in the supply chain, dealing with defective items, common interests
Chapter 1:
Chapter 1 Introduction
Introduction
The title of this thesis is "Order Allocation to Suppliers Using Metaheuristic Algorithms in Xavier Electric Industries Company"
With the passage of time, organizations have seen vast changes in the world due to the advancement in technology, the globalization of markets, the diversity of customers, etc., and with the increase in the number of competitors at the global level, they have tried to improve their internal processes in order to remain in the competitive scene.
Organizations have realized that for Long-term success and survival in the global market must be involved in the management of all organizations that supply the organization's inputs (directly or indirectly) and all organizations that are in charge of delivering and providing after-sales services to customers, and such an attitude has led to the emergence of the supply chain theory[1].
"In general, the supply chain is a chain that includes all the activities related to the flow of goods and the transformation of materials from the stage of preparing the primary material to the stage of delivering the final goods to the customer, and along with the flow of materials, the flow of information and the flow of financial resources will also be established[1].
According to Short product life cycle, organizations must always move ahead of customers and provide new and quality products and at the same time reduce their costs in order to have a higher profit threshold. In most industries, the cost of raw materials and parts used constitutes the major part of product costs, which in some cases can be up to 70%, and even in high-tech organizations, more than 80% of the total cost of the product is related to the cost of purchased materials and services. Therefore, decisions related to purchasing strategies and operations play an important role in the profit of the organization, and decision-making for the correct selection of suppliers has become more important, and choosing the right supplier has been considered as the most important activity of the purchasing department. In fact, it is not possible to propose supply chain management, but expect each of the components to take their decisions based on the interests of their organization as in the past. Win-win thinking should govern all component decisions. Therefore, the concept of coordination in the supply chain today has become one of the important and key issues in the design and management of the supply chain.
Partners in a supply chain, which includes suppliers, manufacturers and distributors, cannot only seek to maximize their profits without considering each other's interests. In this case, the supply chain will lose its true meaning. This is why the issue of coordinating business processes between members of a network to improve the performance and efficiency of the network has become one of the important issues of the supply chain.
In general, the purpose of this research is to help the buyer in selecting suppliers and assigning orders to them in such a way that the most suitable cost is imposed on the organization and at the same time the interests of the supplier are taken into account and the interests of the entire chain are optimized at the same time.
This research is in the form of a case study and the company under study is a switchboard fuse manufacturing company.
In general, in the process of choosing a supplier, three main questions must be answered:
What part is the purpose of ordering?
How many will they supply? And how much should be ordered for each?
In which period should the order be received?
The process of evaluation and selection of suppliers, according to different researchers, includes different steps, which include:
Problem definition
Formulation of criterion(s)
Pre-evaluation[2] Appropriate suppliers
Final selection[3]
In this research, we mean the selection will be the final selection.
Previous studies in the field of supplier selection can be generally classified into the following categories:
Single-source or multi-source
Single-purpose or multi-purpose
Single-product or multi-product
Single-period or multi-period
Existence or absence of a discount strategy
Definite or non-deterministic
To model the supplier selection problem, various methods have been used, the most common of which is the use of mathematical programming. Mathematical programming helps the decision maker to formulate the decision problem according to the mathematical objective function and reach the desired goals by changing the values ??of the variables. Many authors have used single-objective models such as integer or linear programming. In most models, cost is considered as the objective function and other criteria (quality, capacity, delivery time, etc.) are considered as limitations. The two main defects of mathematical programming methods are that the criteria with equal weight are placed in the constraints and the other is that they usually consider quantitative criteria. Some researchers have used multi-objective or ideal linear mathematical programming. Considering that different constraints do not have the same importance, in order to consider this importance in modeling, the use of weighting methods such as TOPSIS and AHP has been considered.
In the initial research of this field, only the purchase costs were considered, but with the passage of time, the costs of warehousing, ordering, transportation, and inspection were also considered.
Considering a variety of cost discount models, penalty costs due to poor quality or late delivery has been one of the further expansions of this field.
To cover the conditions that Prices change intermittently with random behavior over time, attention has been paid to the use of linear programming and dynamic programming. In order to bring the models closer to the real world conditions, recently by using probabilistic and fuzzy models, the uncertainty of the parameters is also included in the models.
In the selection literature, the use of reasoning-based systems has opened its place, the mentioned systems are in the category of famous approaches to artificial intelligence. Basically, these systems have the ability to learn over time by an expert or by using historical data. Non-experts who face similar issues in making decisions can get advice from it.