Document Type : Research Paper

Authors

• Ali Memarpour Ghiaci ¹
• morteza abbasi ²
• Jafar Gheidar-Kheljani ³

¹ Ph.D Student, Industrial Engineering Department, Malek Ashtar University of Technology, Tehran 1774-15875, Iran

² Assistant Professor, Industrial Engineering Department, Malek Ashtar University of Technology, Tehran 1774-15875, Iran

³ Associate Professor, Industrial Engineering Department, Malek Ashtar University of Technology, Tehran 1774-15875, Iran

Abstract

Abstract
Supplier evaluation plays a pivotal role in the success of modular megaprojects, as these projects require capable suppliers due to the necessity for complex coordination among various subsystems and the precise integration of modules. This study proposes an integrated framework for the evaluation of suppliers in modular megaprojects. For the first time, this research applies a novel integrated approach based on the LOPCOW and ARTASI methods, extended using spherical fuzzy sets (SF-LOPCOW and SF-ARTASI) for supplier evaluation. Based on this approach, 31 sustainability-oriented criteria have been identified for evaluating suppliers in modular megaprojects. The criteria are first weighted using the SF-LOPCOW method. Subsequently, in a case study, 12 suppliers identified for a modular megaproject are evaluated and prioritized using the SF-ARTASI method. A comparison of the SF-ARTASI results with other existing multi-criteria decision-making methods in the literature, along with a sensitivity analysis, demonstrates the effectiveness of the proposed approach and the robustness of its results under different scenarios.
Introduction
With the rapid expansion of the global economy, investment in large-scale projects worldwide has increased markedly over the past few decades. Projects with costs of one billion dollars or more are recognized as megaprojects. Megaprojects are inherently associated with growth, development, and competitiveness, acting as the infrastructure of globalization. Modularization is a key driver for reducing the time and cost of megaprojects. With the modularization of megaprojects, the evaluation and selection of suppliers acquire particular importance. The question therefore arises: how can suppliers for modular megaprojects be evaluated in the long term while concurrently reducing project delays? The present study concentrates on this critical issue, which can assist project and megaproject managers from a sustainable development perspective. First, it is essential to collect core criteria from various dimensions—economic, environmental, and social—to evaluate a sustainable supplier; then, by employing a multi-criteria decision-making (MCDM) method, the relative importance of these criteria is determined, and suppliers are subsequently evaluated and prioritized. The supplier evaluation problem is complex and involves uncertainty across all sustainability dimensions (economic, environmental, and social).
The main objective of this study is to evaluate and prioritize suppliers of modular megaprojects by proposing a novel approach under uncertainty. This study intends, for the first time, to apply the developed SF-LOPCOW-ARTASI method to the supplier evaluation problem. This method is capable of handling both uncertainty and group decision-making simultaneously. In this research, the supplier evaluation problem for megaprojects is, for the first time, conducted based on sustainability dimensions within a spherical fuzzy environment. The approach is presented for the first time by using the LOPCOW method developed on the basis of spherical fuzzy sets (SF-LOPCOW) to weight the criteria, and the ARTASI method developed on the basis of spherical fuzzy sets (SF-ARTASI) to prioritize suppliers of modular megaprojects.
Method
The present study employs an integrated approach. In the first stage, supplier evaluation criteria are identified and, after defining the alternatives, data derived from the judgments of the decision-making team are collected as linguistic variables based on spherical fuzzy sets. Subsequently, following the evaluation of suppliers against the identified criteria, the criteria weights are calculated using the SF-LOPCOW method. Finally, by implementing the SF-ARTASI method, suppliers are assessed according to the criteria and prioritized. Using purposive sampling, the decision-making team consisted of eleven experts with experience and specialization in management systems implementation consultancy, engineering, and project and megaproject management. Information on the members indicates that the majority of the expert team have between eight and fourteen years of professional experience.
Discussion and Results
To illustrate the applicability of the proposed approach, suppliers for modular megaprojects were evaluated and prioritized using this approach. In this study, twelve suppliers were assessed and ranked using 31 evaluation criteria. First, each supplier was evaluated by the decision-making team according to the identified criteria using linguistic variables based on spherical fuzzy sets. Given the uncertainty inherent in the evaluation criteria, spherical fuzzy sets were employed to address this uncertainty. The relative importance of the criteria was then determined using the developed LOPCOW method based on spherical fuzzy sets. According to this method, cost, strategy and organization, and the amount of waste generated received the highest importance weights of 0.087, 0.083, and 0.079, respectively. Subsequently, using the proposed approach, suppliers were evaluated and prioritized by applying the developed ARTASI method based on spherical fuzzy sets, taking into account the evaluation criteria and their importance degrees. The results indicate that S3, S9, and S7 ranked first through third, respectively.
Finally, a sensitivity analysis was designed in the form of multiple scenarios to examine the relationship between the outcomes produced by the proposed approach under varying conditions and the study’s findings. This analysis investigated the variation in the final utility function and the resulting ranking of alternatives as the values of φ and α changed; in both cases, the ranges of variation were negligible and not statistically significant.
Conclusion
Due to the need for complex coordination among subsystems and precise integration of modules, the success of modular megaprojects largely depends on the evaluation and selection of capable suppliers. The present study introduces an integrated approach for supplier evaluation in modular megaprojects. Accordingly, a comprehensive list of sustainability criteria for evaluating and prioritizing suppliers of modular megaprojects was identified. The relative importance of these criteria was then determined using the SF-LOPCOW method. Subsequently, following the proposed approach, suppliers were evaluated and prioritized according to the criteria and their importance weights by applying the SF-ARTASI method. The limited number of experts in the field of megaproject management and the absence of weighting expert judgments according to their knowledge and experience represent limitations of this study. The use of aggregation operators to integrate expert judgments, such as the spherical weighted arithmetic mean (SWAM) operator, and the development and comparison of multi-criteria decision-making methods in other uncertain environments (e.g., Pythagorean fuzzy, q-rung, and Fermatean fuzzy sets), and comparing their results with the methods developed in the present study, are suggested for future research. Regardless of the case used to implement the proposed approach, the method is applicable to various supplier evaluation and selection scenarios for megaprojects. In future work, we will extend our research to optimize scheduling and reduce the completion time of modular megaprojects through the employment of appropriate suppliers.

Keywords

• Megaproject management
• Modular megaprojects
• Supplier evaluation
• Multi-criteria decision-making
• Spherical fuzzy sets

Main Subjects

• multiple-criteria decision-making