Managing Resources Based on Inﬂuential Indicators for Sustainable Economic Development: A Case Study in Serbia

: The balance between resource consumption and the ability of natural systems to meet the needs of future generations emerges as a prerequisite of sustainability. Sustainability means aligning economic growth and development with the interest of the environment and social development. Decision-making is a signiﬁcant responsibility in an environment and the business world because decisions affect the ecology and business performance. It is necessary to adopt new approaches in decision-making to ﬁnd an appropriate method for assessing and setting priority goals. Various methods for multi-criteria decision-making have been developed, including the Analytic Hierarchy Process (AHP). The paper deals with the management of natural and human resources for the sustainable economic development of Serbia by selecting inﬂuential factors, relying on a multi-criteria decision-making framework. Appropriate methods have been applied: AHP and several fuzzy AHP (FAHP) approaches. These methods’ application enables the analysis of results from different aspects of expert opinion. Through a case study, this paper investigates the AHP method from several facets in which the identiﬁcation of decision criteria is based on the perception of experts of different proﬁles. The ﬁndings of this research can be a guideline for decision-makers in resource management to enhance sustainable economic development. The case study conﬁrms that the stability of the business environment and business sectors is the most inﬂuential indicator in all scenarios.


Introduction and Literature Review
The sustainable economic development of each state is conditioned primarily by natural (but also human) potentials, which are usually the backbone of the development of the region and the state [1]. Using these potentials while shaping them according to needs, people have survived and developed concerning economic and overall progress. At the same time, technical-technological development and especially the development of ICT has certainly improved everyday life and work without which it is impossible to imagine a modern way of functioning of people and economy, but it has also led to faster exploitation of the human environment, faster depletion of available natural resources [2]. Natural resources are a baseline for development and wealth creation. There is a possibility that the natural regeneration of resources can't keep pace with industry progress. The enrichment of human potential can have a technological impact on increasing the contribution of natural resources to economic growth [3].
Serbia is a territorially small country, but it has quality natural and human resources. The best promotion of socially, environmentally, and economically sustainable growth The strategic management in regional economic development should enable a timely and rational response of the region's economy to all changes in the economic environs in which the region's entities operate [21]. It is necessary to implement pre-planned steps such as analysis of the economic environment, the economic orientation of the district, formulation of the plan of economic development, implementation of the defined strategy, and implementation of strategic control [22].
The paper contains five sections. The introduction provides elementary remarks on the subject area in the framework of managing natural and human resources for the sustainable economic development of the region and literature review. The Section 2 provides the conceptual framework. The methodology, which consists of AHP, and fuzzy triangular AHP methods, is given in the Section 3. After them in this section, indicators are chosen within four different groups. Section 4 part presents the ranking results and comparison of the results of the given algorithms with the discussion. Concluding remarks and future research goals have been presented in the last Section 5.

Conceptual Framework
One of the basic concepts of the economics of natural resources and the environment is the concept of sustainable development. Despite the different interpretations that can be found in the literature, this concept today has a central place in considering the long-term perspective of the survival and progress of human race in aligning economic growth and development with the interests of environmental protection and social development.
The research process adopted in this paper is realized as Figure 1 shows. employment rate, investment, and competitiveness on the international market [18]. To use all the potential, serious work, strong leadership, and a clear vision have been necessary [19]. Strong leadership, setting investments as priorities for municipal activities, with focused work and energy can make a difference, as shown by the examples of some successful municipalities [20]. The strategic management in regional economic development should enable a timely and rational response of the region's economy to all changes in the economic environs in which the region's entities operate [21]. It is necessary to implement pre-planned steps such as analysis of the economic environment, the economic orientation of the district, formulation of the plan of economic development, implementation of the defined strategy, and implementation of strategic control [22].
The paper contains five sections. The introduction provides elementary remarks on the subject area in the framework of managing natural and human resources for the sustainable economic development of the region and literature review. The second section provides the conceptual framework. The methodology, which consists of AHP, and fuzzy triangular AHP methods, is given in the third section. After them in this section, indicators are chosen within four different groups. The fourth part presents the ranking results and comparison of the results of the given algorithms with the discussion. Concluding remarks and future research goals have been presented in the last fifth section.

Conceptual Framework
One of the basic concepts of the economics of natural resources and the environment is the concept of sustainable development. Despite the different interpretations that can be found in the literature, this concept today has a central place in considering the longterm perspective of the survival and progress of human race in aligning economic growth and development with the interests of environmental protection and social development.
The research process adopted in this paper is realized as Figure 1 shows. The paper presents the factors that influence the managing natural and human resources for the economic development of Serbia through four groups (a framework for strengthening participation in the development, human social resources, economic potentials, and natural resources). Modeling a framework for supporting participation and 1.
• A framework for managing natural and human resources for sustainable economic development • Literature review 2.
• Methodology: AHP and triangular FAHP • Indicators involved in sustainable economic development 4.
• Recruiting pairwise comparisons among decision elements and application of algorithms in influential indicators modeling for sustainable economic development 5.
• Ranking and selection of influential indicators as measures affecting the susteinable economic development The paper presents the factors that influence the managing natural and human resources for the economic development of Serbia through four groups (a framework for strengthening participation in the development, human social resources, economic potentials, and natural resources). Modeling a framework for supporting participation and managing resources in the sustainable economic development of Serbia is considered in this research from the aspect of crisp AHP and fuzzy approaches of method AHP to single out influential factors. Managers show interest in creating and implementing reliable modus for decision-making in the present and the future. Achieving sustainable development requires developing an appropriate strategy to achieve sustainable development by applying maintenance performance measurements [23]. The method Analytic Hierarchy Process (AHP) Sustainability 2022, 14, 4795 4 of 20 was introduced by Thomas L. Saati in 1980 [24,25]. It is a method for solving multi-criteria decision-making (MCDM) problems. After a comprehensive evaluation of several criteria, it points to the final choice of the best solution in the analyzed problem [26]. The AHP method is widely used, despite the need for consistency testing, primarily because of its flexibility and ease of use [27]. Many methods and applications of fuzzy AHP are expressed by numerous researchers [28,29]. In applying the Fuzzy Analytic Hierarchy Process (FAHP) method, we used Chang's Extent analysis method (EAM) approach and the three-level optimism approach [30,31]. The results obtained by explained methods are compared with the results given by Interval AHP (IAHP) as in the paper [28].
The goal is to single out influential factors obtained by methods application and compare the results. The task of the paper is to compare the extent to which these approaches can influence the decision choice of influencing factors. The methods used are given in Figure 2.
managing resources in the sustainable economic development of Serbia is considered in this research from the aspect of crisp AHP and fuzzy approaches of method AHP to single out influential factors. Managers show interest in creating and implementing reliable modus for decision-making in the present and the future. Achieving sustainable development requires developing an appropriate strategy to achieve sustainable development by applying maintenance performance measurements [23]. The method Analytic Hierarchy Process (AHP) was introduced by Thomas L. Saati in 1980 [24,25]. It is a method for solving multi-criteria decision-making (MCDM) problems. After a comprehensive evaluation of several criteria, it points to the final choice of the best solution in the analyzed problem [26]. The AHP method is widely used, despite the need for consistency testing, primarily because of its flexibility and ease of use [27]. Many methods and applications of fuzzy AHP are expressed by numerous researchers [28,29]. In applying the Fuzzy Analytic Hierarchy Process (FAHP) method, we used Chang's Extent analysis method (EAM) approach and the three-level optimism approach [30,31]. The results obtained by explained methods are compared with the results given by Interval AHP (IAHP) as in the paper [28].
The goal is to single out influential factors obtained by methods application and compare the results. The task of the paper is to compare the extent to which these approaches can influence the decision choice of influencing factors. The methods used are given in Figure 2.

Materials and Methods
AHP is a structured technique that enables the organization and analysis of complex decisions based on subjective assessment. Using multiple criteria for easy to understand and efficient dealing with qualitative and quantitative data are the main advantages of AHP. Definition 1. AHP is a multi-criteria decision-making technique to highlight the advantages among different criteria in the decision-making, compare decision-making alternatives for each criterion, and obtain the final ranking of decision alternatives. The outcome in AHP is deciding on the best of the decision alternatives.
The AHP method is realized through the following steps [35]: (1) Establishing a hierarchy by decomposing the problem of decision-making.

Materials and Methods
AHP is a structured technique that enables the organization and analysis of complex decisions based on subjective assessment. Using multiple criteria for easy to understand and efficient dealing with qualitative and quantitative data are the main advantages of AHP. Definition 1. AHP is a multi-criteria decision-making technique to highlight the advantages among different criteria in the decision-making, compare decision-making alternatives for each criterion, and obtain the final ranking of decision alternatives. The outcome in AHP is deciding on the best of the decision alternatives.
The AHP method is realized through the following steps [35]: (1) Establishing a hierarchy by decomposing the problem of decision-making. AHP has been used in various domains like business, industry, and engineering. Developing countries should use AHP for complex economic problems solutions from different development perspectives [36]. The essence of the AHP method is to pair the available options according to all evaluation criteria [37]. In the real world, data or information obtained from experts mainly includes uncertainty and ambiguity conditioned primarily by inaccuracies in human reasoning and decision-making environment uncertainty and incomplete details [38].
As a more powerful methodology for multi-criteria decision-making, the combined effect of fuzzy set theory and AHP is given by the FAHP. The FAHP method is applicable for solving the problem of multi-criteria analysis when accurately assessing (quantifying) the impact of indicators on the decision problem is not present. In addition, the introduction of the AHP or FAHP method allows minimizing subjective influences in decision-making.

Triangular Fuzzy Numbers and Fuzzy AHP Method
The fuzzy numbers are special fuzzy sets is a continuous function. The triangular fuzzy number (TFN), denoted with T = (a, m, b), has membership function: (1)
In recent decades, the fuzzy AHP method, based primarily on triangular fuzzy numbers, has proven suitable in a wide range of engineering, environment, industry, economy, etc. Since fuzzy weights are not as easy to calculate as crisp weights, most Fuzzy AHP applications use the extent analysis method proposed by Chang [30]. Like AHP, FAHP facilitates decompositions and comparisons in pairs, provides a hierarchical structure, and generates priority vectors while reducing in-consistencies. Also, fuzzy AHP can be used to solve different problems and different contexts.
The applied method consists of the following: (1) Establishing the main goal and the criteria and sub-criteria contributing to the overall goal; developing the problem hierarchy. (2) Obtaining the fuzzy comparison matrices. A pairwise comparison has been made using a fuzzified evaluation scale. Using triangular fuzzy numbers, we form a comparison matrix C = c ij n×n for a fuzzy comparison of criteria by pairs, where c ij is a fuzzy value that expresses the relative importance of one criterion to another. At the diagonal, the fuzzy values c ii express the relative importance of the criterion to itself. Because of that, we put that c ii = (1, 1, 1). The aggregation of different experts' opinions is calculated by the averaging method. Based on the corresponding linguistic assessments of k experts (a i , m i , b i ), aggregated crisp value has been obtained by 1 /k ∑ k i=1 m i rounding to the nearest integer. The corresponding fuzzy number value of the aggregate opinion is then obtained. (3) Examination of the comparison matrix C consistency. We calculate the consistency index CI and consistency ratio CR for matrix C = c ij n×n by CI = λ max −n n−1 , CR = CI RI , where λ max represents the maximal eigenvalues, and RI is an accepted random index of a matrix C. The value CR ≤ 0.10 implies that we accept evaluated fuzzy elements of the matrix, while otherwise, we must remove the reasons for undesirably high estimations and repeat comparison in pairs until the degree of consistency belongs to desirable limits. (4) The fuzzy synthetic extents determination. The synthetic triangular fuzzy numbers have been calculated, according to Chang's extent analysis method, by using triangular fuzzy numbers from the matrix C = c ij n×n : First approach, Extent analysis method (EAM) [30]: The obtained synthetic triangular fuzzy numbers can be compared one with each other by calculating the degree of possibility that T 1 ≥ T 2 : This probability P has been approximated by the ordinate of the intersection point with abscise d (see Figure 3). fuzzy value that expresses the relative importance of one criterion to another. At the diagonal, the fuzzy values ̃ express the relative importance of the criterion to itself. Because of that, we put that ̃ = (1,1,1). The aggregation of different experts' opinions is calculated by the averaging method. Based on the corresponding linguistic assessments of k experts ( , , ), aggregated crisp value has been obtained by ∑ rounding to the nearest integer. The corresponding fuzzy number value of the aggregate opinion is then obtained.
(3) Examination of the comparison matrix consistency. We calculate the consistency index and consistency ratio where λ represents the maximal eigenvalues, and RI is an accepted random index of a matrix . The value ≤ 0.10 implies that we accept evaluated fuzzy elements of the matrix, while otherwise, we must remove the reasons for undesirably high estimations and repeat comparison in pairs until the degree of consistency belongs to desirable limits. (4) The fuzzy synthetic extents determination. The synthetic triangular fuzzy numbers have been calculated, according to Chang's extent analysis method, by using triangular fuzzy numbers from the matrix = ̃ × : First approach, Extent analysis method (EAM) [30]: The obtained synthetic triangular fuzzy numbers can be compared one with each other by calculating the degree of possibility that ≥ : This probability P has been approximated by the ordinate of the intersection point with abscise d (see Figure 3). By calculating ordinate of this intersection point, we obtain The degree of possibility that convex fuzzy number is greater than convex fuzzy numbers , = 1, is By calculating ordinate of this intersection point, we obtain The degree of possibility that convex fuzzy number T is greater than k convex fuzzy numbers n are n elements. The normalized weight vector is a non-fuzzy number: which we can denote W = (ω 1 , ω 2 , . . . , ω n ) T . Second approach: Based on total integral values calculated by [39], We compare obtained TFNs: S i = (a i , m i , b i ). Real constant ν represents an optimism index, which explains the decision maker's attitude toward the risk. The smaller values mean a higher degree of risk and a lower degree of optimism. In our research we have used values: ν = 0 (pessimistic viewpoints), ν = 0.5 (balanced viewpoints), and ν = 1 (optimistic viewpoints).

Considering Indicators for the Sustainable Economic Development
Factors influencing the implementation of the concept of natural and human resources management for the economic development of Serbia are expressed through four groups of criteria: a framework for strengthening participation in development, human resources, economic potential, natural resources, and are shown in Table 1. Table 1. The overview of adopted indicators for the sustainable economic development.
S-Strengthening participation in the development [40] S 1 -Economic development strategy based on knowledge and innovation [41,42] S 11 -Development of a stimulating entrepreneurial environment [43] S 12 -Targeted investment attraction [44] S 13 -Development of potentials for the needs of the labor market S 2 -Sustainable mobility and interactive city development [45,46] S 21 -Increased accessibility of the city S 22 -Sustainable mobility of the central city zone [47] S 23 -Development of economic zones and logistics S 24 -Compliance of the traffic system with the needs of citizens S 25 -Increasing the share of pedestrians in cyclists as road users [48] S 26 -Improved safety conditions for all road users S 3 -Improvement and development infrastructure services of citizens [49] S 31 -Improving the quality of communal infrastructure S 32 -Creating a framework for high-quality utilities S 33 -Improving the level of information and communication with citizens S 4 -Energy capital as a development opportunity [50] S 34 -Increased efficiency coefficient of all PUCs individually S 41 -Improvement of energy infrastructure S 42 -Improving energy efficiency S 43 -Institutional environment for the development of energy systems and the provision of quality services [51] S 5 -Improved social cohesion [52] S 44 -Achieved in the billing system according to the energy consumed S 51 -Diversified, accessible, and quality social services S 52 -Improving the content of culture, sports, and tourism S 53 -Improving social development infrastructure S 54 -A single record system for users of social rights and services has been established S 55 -City Housing Strategy adopted S 56 -Implementation of investment plans in facilities and equipment of primary health care institutions E-Economic potentials [ N-Natural resources [63] N 1 -Use and protection of natural resources in planning [64] N 11 -Implementation of the National Strategy on the Use and Protection of Natural Resources and Goods N 12 -Strategic environmental impact assessment of plans and programs N 13 -Environmental impact assessment of projects N 14 -Integrated prevention and control of environmental pollution N 2 -Management of renewable natural resources and non-renewable natural resources [65] N 21 -Reconciliation of the relationship between the degree of exhaustion of natural resources and their regeneration rate [66] N 22 -Design of available resources by quality, structure, amount, and capital investments N 23 -Direction of ecological aspects in the interest of the population of the local area N 3 -Protection of resources and ecosystems through the principles of sustainable development [67] N 31 -Creating ability of the environment to accept a certain amount of pollutants per unit of time and space so that there is no irreversible damage to the environment; N 32 -The impact of a product/service or system on the environment N 33 -Effective preservation of ecosystems and resources themselves [68] N 34 -Transparency-information of the wider local community H-Human resources [

Results and Discussion
In this section, the outlined algorithms have been applied. A group of experts in the area of economy, natural resources, and human resources rated the identification of decision criteria. Expert opinions are expressed based on the meaning and denotation of TFNs in Table 2. Expert assessments are aggregated based on the algorithm explanation in step (2). Experts agreed that some groups should retain a number of sub-criteria. Table 3 shows a matrix comparing the primary criteria, and Figure 4 shows the corresponding weights.
Tables A1-A20 with triangular fuzzy comparison matrices of sub-criteria and the corresponding weights for applied methods are in Appendix A.
The final rank of sub-sub-criteria, and their final weight for each sub-criterion, are in Table 4. The indicators are ranked according to the optimistic, balanced, and pessimistic views (ν = 1, ν = 0.5, ν = 0), the extent analysis method (EAM) on FAHP and AHP.   Tables A1-A20 with triangular fuzzy comparison matrices of sub-criteria and the corresponding weights for applied methods are in Appendix A. The final rank of sub-sub-criteria, and their final weight for each sub-criterion, are in Table  4. The indicators are ranked according to the optimistic, balanced, and pessimistic views ( = 1, = 0.5, = 0), the extent analysis method (EAM) on FAHP and AHP.   The final sequence of influencing factors (with weights) in managing natural and human resources for economic and regional development can be seen in Figure 5.
The results obtained by applying classical AHP and FAHP methods, whether they are different degrees of optimism or Chang's approach, are favored as the most influential factor stability of the environment and business sector.
Based on the obtained final weights that represent the optimistic attitudes of decisionmakers, the following are significant reductions in the pressure of public investment on the budget, efficient conservation of ecosystems and resources, and the global response to the COVID-19 pandemic. In the pessimistic scenario, the following indicators stand out: the development of a stimulating entrepreneurial environment, reducing the pressure of public investment on the budget, and global response to the COVID-19 pandemic. In the balanced scenario, the development of a stimulating entrepreneurial environment, reducing the pressure of public investments on the budget, efficient preservation of ecosystems and resources, as well as the global response to the COVID-19 pandemic are still important indicators.
Differences can be seen in the second factor of influence Chang's approach and optimistic attitude favor reducing the pressure of public investment on the budget, and moderate and pessimistic attitudes, as well as the AHP method, emphasize the development of a stimulating entrepreneurial environment.
In both scenarios, the same group of indicators stands out by the dominant factor being the stability of the business environment and the business sector. However, the development of a stimulating entrepreneurial environment is not among the significant factors in the optimistic scenario, unlike the pessimistic one. On the other hand, efficient conservation of ecosystems and resources themselves resource-related environmental factors are not so significant in this scenario. The final sequence of influencing factors (with weights) in managing natural and human resources for economic and regional development can be seen in Figure 5.  Although sustainable development has three dimensions: economic, environmental, and social, we have included in this study another dimension of the framework for strengthening participation in development to establish the extent to which indicators that stand out within this group affect economic growth and regional development. The optimistic scenario includes only one of these factors as the dominant ones, the targeted attraction of investments. The results obtained using the IAHP method favor precisely the indicators from this dimension because the estimates given using the interval method defined wider intervals that favored this group of factors. Thus, the most significant indicators by IAHP are the development of a stimulating entrepreneurial environment, targeted investment attraction, reducing the degree of the gray economy in GDP, effective preservation of ecosystems and resources themselves.
The measure chosen for the realization of comparative analysis of criterion weighting methods presented in this research is one of the most frequently used rank correlation coefficients used today to solve the problem of MCDM. Spearman's correlation coefficient represents the measure of the strength and direction of the correlation between two ranked criteria [76]. This coefficient is given by (8) where r x i and r y i are ranks of the element i in the compared rankings, n is the number of elements in the ranking. WS method rank correlation coefficient is new, and was introduced in [77]. The main goal of this coefficient is to choose indicators that are closer to the top of the considered ranking. It provides a typical ranking scenario where the first three places are the most significant and targets differences in the given ranks depending on what changes in positions are observed. This coefficient is used in many decision-making problems and coefficient is calculated as shown in (9) A comparative analysis of the similarity of the methods is given in Table 5.

Conclusions
Managing natural and human resources for economic and regional development is a global challenge that requires attention and importance in every society guided by the

Optimistic scenario (FAHP)
•Stability of business environment and business sectoreas •Reducing the pressure of public investment on the budget •Effective preservation of ecosystems and resources themselves •Global response to the COVID-19 pandemic •Targeted investment attraction •Creating ability of the environment to accept a certain amount of pollutants per unit of time and space so that there is no irreversible damage to the environment •Reconciliation of the relationship between the degree of exhaustion of natural resources and their regeneration rate.

Pessimistic scenario (FAHP)
•Stability of the business environment and business sector •The development of a stimulating entrepreneurial environment •Reducing the pressure of public investment on the budget •Global response to the COVID-19 pandemic •Targeted investment attraction •Effective conservation of ecosystems and resources themselves •Increase in efficiency and economy.

Balanced scenario (FAHP)
•Stability of business environment and business sectoreass •The development of a stimulating entrepreneurial environment •Reducing the pressure of public investment on the budget •Effective conservation of ecosystems and resources themselves •Global response to the COVID-19 pandemic •Targeted investment attraction •Creating ability of the environment to accept a certain amount of pollutants per unit of time and space so that there is no irreversible damage to the environment.

Chang approach (FAHP)
•Stability of business environment and business sectoreas •Reducing the pressure of public investment on the budget •The development of a stimulating entre-preneurial environment •Effective conservation of ecosystems and resources themselves •Increase in efficiency and economy. •Creating ability of the environment to accept a certain amount of pollutants per unit of time and space so that there is no irreversible damage to the environment •Targeted investment attraction.

Conclusions
Managing natural and human resources for economic and regional development is a global challenge that requires attention and importance in every society guided by the principles of sustainable development. Natural resources underpin economic activities in many ways. Issues about socially, environmentally, and economically sustainable promotion of growth in the best way have been increasingly at the heart of the interest. The strategy of economic development of the region includes defining a model for achieving the planned evolution of the state. Developing countries can apply a multi-criteria analysis in assessing and solving complex solvency problems from different perspectives. This paper examines the influential factors of sustainable economic development, taking into account the naturally available wealth also human resources as the backbone of the development of the region's economy. The paper discusses indicators divided into four groups a framework for strengthening participation in development, human social resources, economic potential, and natural resources. In recent decades, the FAHP method, based primarily on triangular fuzzy numbers, was proven suitable in a wide range of fields of engineering, environment, industry, economy, etc. The approach in the indicators' evaluation, given by unclear numbers, was significantly influenced the final results from the determination of influencing factors. Using methods, AHP and triangular fuzzy AHP, 57 different subcriteria are ranked for identifying priorities in resource management and economic regional development. The triangular fuzzy of the AHP indicates the importance of the stability of the environment and the business sector for different degrees of optimism, namely the Chang approach and the classic AHP. The IAHP approach indicates the importance of stimulating entrepreneurial environment development. The analysis of the similarity of the results gives a generally satisfactory degree of similarity, although the second indicator already differs in some scenarios. The proposed model offers five scenarios, and it is up to the managers to decide on the most acceptable option. Such a proposal provides enough flexibility for the decision-maker. In future research, we intend to apply the spherical fuzzy analytic hierarchy process to find the best model to support IoT influence factors of entrepreneurship.

Acknowledgments:
The authors express gratitude to the Ministry of Education, Science, and Technological Development of Serbia for providing partial support for this paper.

Conflicts of Interest:
The authors declare no conflict of interest.