Master's thesis, field of industrial management, operations research orientation
September 2010
Abstract
How and how to choose has long been the subject of discussion by philosophers and scientists, so achieving satisfactory results requires following a rational and logical path in the selection process. The growth and development in the last few decades, as well as the more competitive business market, have made organizations and large companies to find a specialized and scientific approach to the process of selecting contractors and implementing projects. What is certain is that the selection of the right and qualified contractor will guarantee the success of the project, and vice versa, the inability to identify and choose the right contractor will result in ineffectiveness and losses.
According to the municipality's policy of outsourcing activities, more and more contracting companies are participating in various municipal projects, including projects related to green spaces; And this multiplicity of contracting companies has made choosing a competent contractor a serious and decisive matter for the municipality as an employer. Therefore, the correct selection of contractors is the first step on the way to achieve the desired goal of employers, i.e. project implementation within the desired time frame with a specified cost and desired quality. For this purpose, after reviewing the literature related to the identification of criteria and interviews with experts and municipal managers, 33 primary criteria for contractor selection and evaluation were identified, and by applying the fuzzy hypothesis test, 15 criteria were considered as the most important criteria affecting the selection of contractors. Then, the fuzzy hierarchical analysis technique was used to weight the criteria, and finally, 5 municipal green space contractors were evaluated and ranked using the TOPSIS fuzzy method.
Key words: contractor[1], fuzzy logic[2], hierarchical analysis process[3], TOPSIS distance[4]
Chapter 1
Generalities of the research
Introduction:
In this research, an attempt has been made to introduce comprehensive indicators for the selection of contractors for municipal green space projects with a broad review of the literature on contractor selection. This is the first step to provide a practical and effective contractor selection model. The above criteria and indicators should be developed in such a way that they cover the concepts of cost, time and quality well and with a high margin of confidence. Based on these three main concepts, a list of criteria can be created. Among these three indicators, quality is a more complex category, which requires extensive research to determine its amount and how. The time scope of the implementation of a project is determined by the employer in a schedule, and deviation from this time frame will usually result in heavy fines for the contractor. The cost is generally interpreted as the price that the employer will ultimately pay to complete the project, but the cost can also include things such as the contractor's inability to complete the contract, re-implementation of parts of the project, re-tendering and so on.
Also, in the real world, due to the existence of incomplete and ambiguous information, the data required for decision-making are usually imprecise. In such a situation, for more realistic decision-making, the theory of fuzzy sets is more effective. In this research, the fuzzy multi-criteria group decision-making approach based on the distance TOPSIS method [1] is used to evaluate and select the contractor. In this chapter, an attempt is made to provide a suitable definition of the research problem, objectives and questions. suitable and qualified will guarantee the success of the project implementation, and vice versa, the inability to identify and choose the right contractor will result in ineffectiveness and losses. Each employer defines expectations from the contractor and different aspects of a project according to their strategy. The strategy of an organization determines the attitude of an organization to the basic concepts of choosing a contractor, i.e. time, cost and quality, and finally, the employer's expectations from the contractor of a project determine the framework of how to choose.
How and how to choose has long been the subject of philosophers and scientists discussion, what is certain is that achieving satisfactory results requires following a rational and logical path in the selection process. The employer's commitment to the successful implementation of the project and the effort to create harmony in the employer-contractor complex is an important factor in achieving the expected results.
The trend of growth and development in the last few decades, as well as the business market becoming more competitive, has caused organizations and large companies to have a specialized and scientific approach to the process of selecting a contractor as well as the implementation of projects, and to find concepts such as reducing costs, in the management and organization of superior projects. turn around Today, you can see call for tenders for small and large public and private projects in newspapers and magazines daily. For an organization, the first step to achieve the desired results regarding outsourced projects is to choose the right contractor. A project is successful when it is put into operation in a certain time, its costs are within the set framework and finally it meets the expected quality. Based on these three main concepts, a list of criteria can be created.
Time: The project completion time is defined as making it possible to use the plan near a certain day determined by the employer's future plans. The degree of willingness of employers to employ only contractors who meet the target date differentiates them from each other. Some contracts have clauses for bonuses to encourage contractors to speed up the construction process and avoid any delays. Cost: Historically, cost has been considered the most important factor by employers. Most employers are looking for value for money. One of the results of this is that the cost calculated through the suggested price provided by the contractor is often considered as the only criterion for selecting the contractor. The vast majority of projects, however, end up costing more than the original bid price.
Quality: Quality in the project, as "the totality of characteristics that a product or service needs to satisfy a certain need". It is defined. There is always an alternative relationship between cost, time and quality, in such a way that the employer tries to establish a balance between these variables and the importance assigned to each one that has the ability to dominate the decision to choose a contractor (Hault [2] et al., 1995). Municipal green space projects should be introduced. This is the first step to provide a practical and effective contractor selection model.
In fact, many existing models focus only on the quantitative criteria of contractor selection; While some of the criteria that we will face in this research will be qualitative. In other words, the criteria for choosing a contractor are both qualitative and quantitative.
According to what was mentioned, it can be easily concluded that the nature of choosing a contractor is a multi-criteria issue. It is brought up. As a result, multi-criteria decision-making models [3] are used to select and prioritize options based on the selected criteria. The TOPSIS method is one of the multi-criteria decision-making methods that was first proposed by Huang in 1981. But what is important is that in today's world, data is usually not clear and human judgments are sometimes vague and cannot be expressed with numerical values. Therefore, it can be said that the decision-makers are faced with uncertainty in the issue of contractor selection, in this regard, the use of fuzzy logic can be effective. The use of this logic and this type of attitude towards natural phenomena was first suggested in 1965 by Dr. Lotfollah Asgarizadeh (Casco, 1377).
In this research, we specifically seek to rank municipal green space contractors with a fuzzy multi-criteria group decision-making approach using the distance TOPSIS method.