The Fuzzy DEMATEL-ANP (standing for Decision-Making Trial and Evaluation Laboratory – Analytic Network Process) is considered as  a hybrid MCDM  ( representing  multi-criteria decision-making ) approach  that i incorporate two powerful techniques,  namely DEMATEL and ANP, increased by using fuzzy set theory to manage  both the uncertainty and vagueness which are  inherent in human judgment and  decision Processes. The hybrid methods can be employed to model the complicated systems and decision problems involving interconnected and mutually dependent criteria, which are common in the realistic and relevant situations.  The robustness is added to the decision-making process using a fuzzy element in order to capture inaccuracy in human evaluations, making it especially appropriate for the situations where subjective judgments and decisions dominate.

In this detailed description, we will address the basic concepts behind DEMATEL, ANP, and fuzzy set theory, followed by the incorporation of these techniques into the Fuzzy DEMATEL-ANP method. We will also discuss its mathematical framework, applications, and advantages over other MCDM methods. .

DEMATEL Technique

 

 The Fundamentals of DEMATEL Technique

 DEMATEL is considered as a technique designed for both the analysis and visualization of  the structure of complicated  problems by determining the  causal relations among factors. It was first developed to deal with the very complicated and interdependent nature of real-world systems, especially in areas, such as engineering, management, and social sciences. DEMATEL technique can assist decision-makers to understand how various factors affects one another and which factors can play a significant l role in the SD (standing for system dynamics).

The crucial stages involved in the DEMATEL process are as follows:

– The determination of factors: The first stage is to identify  all factors or criteria that  can affect the decision- making process  or system.

– Pairwise comparisons: Decision-makers are asked to identify similarities and differences among these factors contributing to the pairs using a scale to define the strength of effect one factor on another. For instance, a scale ranging from 0 (no effect) to 4 (very strong effect) can be employed.

– Matrix of direct influence (MDI): These pairwise comparisons can be applied to create a MDI, where the elements denote the effect one factor has on another.

– Matrix of total influence: The MDI can be employed to compute a matrix of the total influence, integrating   both direct and indirect influences.

–   The determination of threshold rate: A threshold value is set to filter out less significant effects , allowing the decision-makers to concentrate  on the most important relations.  .

– The creation of causal diagram: Finally, a causal diagram or network is created, indicating which factors are influential (cause) and which influenced (effect) are. The diagram presents a visual understanding of a system structure.

ANP Technique

 

An Overview of ANP Technique

ANP,   as an extension of the AHP (representing Analytic Hierarchy Process),  was developed by Thomas L. Saaty, to explore more complicated  decision-making  problems involving interdependencies among criteria. While AHP technique considers a hierarchy where criteria are independent, it relaxes this assumption and takes the interrelated criteria into consideration. This can be obtained by creating a network, where elements can affect each other in a feedback loop.

 

 ANP method includes the following crucial stages

– Modeling of the decision problem: The first stage is to identify the goal, criteria, sub-criteria, and alternatives. In ANP technique, these elements are organized in a network rather than a hierarchal structure.

– Pairwise comparisons: like AHP method, decision-makers are asked to carry out pairwise comparisons between elements for determining their relative influence or significance. However, in ANP method, feedback and interdependencies among elements are examined by these comparisons.

–  The creation   of supermatrix: The results obtained from pairwise comparisons are employed to create a supermatrix, capturing the effect of each element on others. The supermatrix is a major part of ANP method because it indicates the network of interdependencies in the decision problem.

– Limiting the supermatrix: To put the elements in order of their relative importance and get global weights, the supermatrix can be normalized and raised to a limiting power until it converges, resulting in the final rankings of elements.

 Fuzzy Set Theory

Introduction to Fuzzy Sets

Traditional decision-making approaches   usually  depend on  booth crisp values and definitive judgments. However, real-world problems are filled with uncertainty, ambiguity, and vagueness. Fuzzy set theory, proposed  by Lotfi Zadeh in 1965, presents  a mathematical framework for managing  the  uncertainty by enabling  partial membership in a set, as contrasted with the binary membership utilized  in classical set theory.

 

In fuzzy set theory

– A fuzzy set is characterized by a membership function that allocates a value between 0 and 1 to each element, indicating  the degree of membership in the set.

– Linguistic variables (low, medium, and high) can be modeled  by fuzzy sets, making it easier to show  subjective judgments.

– Fuzzy numbers, especially   both TFNs ( standing for the  triangular fuzzy numbers) and trapezoidal fuzzy numbers,  can be employed to model  the numerical uncertainty.

 In decision-making, fuzzy set theory provide for for the integration  of inexact and vague information, making it a useful tool for modeling human judgments and decisions, which are often subjective and uncertain.

 Fuzzy DEMATEL-ANP-Based Technique

 

The strengths of DEMATEL, ANP, and fuzzy set theory  are combined by the Fuzzy DEMATEL-ANP-based technique to explore the complicated  decision-making problems involving  interdependencies among criteria and uncertainty in judgments.  The following is a step-by-step outline of how this hybrid method  works:

Determining Criteria and Building  a Decision Model

The first stage involved  in the Fuzzy DEMATEL-ANP technique is to define the decision problem by determining the criteria, sub-criteria, and alternatives. The decision model is built  in the form of a network, indicating  the interdependencies among criteria. These interdependencies are considered as  a major  feature of the ANP technique and provide  for a more realistic representation of complicated systems.

 Fuzzy Pairwise Comparisons

Fuzzy pairwise comparisons are performed When the criteria are determined.. Instead of employing  the crisp values to compare the significance  or influence of one criterion over another, linguistic terms(low, medium, and high)   are used by decision-makers  in order to express their judgments. These linguistic terms are then converted into fuzzy numbers, usually triangular fuzzy numbers,  demonstrating  the uncertainty in human judgment.

 For instance, a linguistic judgment of “medium” might be denoted  by a triangular fuzzy number (2, 3, 4), where 2 represents the lower bound, 3 denotes  the most likely value, and 4 indicates the upper bound. The the pairwise comparisons matrices with fuzzy elements are is created  for both the DEMATEL and ANP processes.

 DEMATEL Phase: Fuzzy Matrix of Direct Influence

In the DEMATEL phase, the fuzzy pairwise comparisons of criteria  are used to constructa fuzzy matrix of direct influence... The matrix elements are fuzzy numbers showing  the degree of effect of one criterion over another. The matrix is employed  to compute  the fuzzy matrix of  total influence, incorporating  both direct and indirect effects. .

  For simplifying an analysis, the fuzzy matrix of  total influence is defuzzified (i.e., converted back to crisp values) via  techniques used for  defuzzification, including  the centroid method or the mean of maximum. This crucial step is used to determine  the most significant  criteria and relations in the system.

 Threshold and Causal Diagram

A threshold value can be  determined to filter out less important  relations in the influence matrix. This enables  decision-makers to concentrate on the most significant  causal relations. A causal diagram is then created  based on the defuzzified matrix  of total influence. The diagram visually displays  the causal structure of the decision problem, indicating  which criteria are the most influential.

 ANP Phase: Formation and Normalization of A Supermatrix

In the ANP phase, the fuzzy pairwise comparisons are employed  to create  a fuzzy supermatrix, capturing  the effect  of criteria on one another in the network. To achieve  a crisp supermatrix, the fuzzy supermatrix is then normalized and defuzzified.  

 The supermatrix is raised to a limiting power until it converges, resulting in  the final ranking or weight of each criterion . These weights show  the relative significance  of criteria, taking the interdependencies among them into consideration.

 Synthesis and Decision-Making

The results  obtained from the DEMATEL and ANP phases are synthesized to get  a a deep, thorough understanding of the decision problem. The causal relations determined  in the DEMATEL phase can assist  decision-makers  to understand the  system structure, while the priorities of  the ANP phase presents  a quantitative ranking of each criterion.

The final decision is made based on these insights, taking into account both the causal relations and the relative significance  of each criterion.

Applications of Fuzzy DEMATEL-ANP Technique

 

The Fuzzy DEMATEL-ANP technique  can be applied in many fields, including:

– Supply chain management: (SCM) To determine  the crucial  factors influencing  supply chain performance and arrange the improvement strategies.

– Project management: To examine  the interdependencies among project risks and arrange strategies  of risk reduction.

– Sustainability evaluation: To assess the sustainability of products or services by  taking  environmental, social, and economic factors into consideration.

– Healthcare decision-making process: To evaluate  healthcare policies or interventions by inveatigating  the complex relations among healthcare criteria.

Benefits of Fuzzy DEMATEL-ANP Technique

 – Managing  Interdependencies: dissimilar to traditional methods, the Fuzzy DEMATEL-ANP technique clearly takes  the interdependencies among criteria into consideartion, presenting  a more realistic accuracy model model of decision problems.

Integration of Uncertainty: Fuzzy set theory enables  decision-makers to present  their judgments using linguistic terms, which are more intuitive and better adapted for managing  both  uncertainty and inaccuracy .

– Causal Analysis: The DEMATEL phase of the  method  presents  the useful  insights into the causal structure of the problem, which can assist decision-makers to understand how different criteria affect  one another.

Conclusion

The Fuzzy DEMATEL-ANP-based technique is a useful  tool  used for decision-making  process in complicated , interdependent systems with inherent uncertainty. By incorporating  the strengths of DEMATEL, ANP, and fuzzy set theory, this hybrid approach  provides  a thorough and robust framework  to  analyze and solve  real-world decision problems.  It has  the ability to model interdependencies, manage  uncertainty, and  present  a visual representation of causal relations makes it an ideal option  for decision-makers involved  in many  fields.