3.2.1. MacBeth Implementation of the Method

The preliminary assessment phase was useful for processing the data collected, through focus groups and questionnaires, and defining the alternatives/functions to be included in the cultural heritage under study.

The participatory process has allowed users to acquire local information, analyze possible conflicting behaviors, and produce more preferable and shared alternatives. In this phase, four groups of stakeholders have been identified:


The questionnaires were administered to the community and to the association- s representatives; focus groups involved representatives of institutions and technical-professional organizations.

Below is the list of functions deduced from the participatory process.


For the evaluation of the priorities of the alternative functions to be used for the implementation of the scenarios, the MacBeth evaluation method [72–74] wich was chosen for the possibility of processing qualitative judgments from various data sources (focus groups and questionnaires). This method uses a synthetic matrix, which links options (functions) to potential multi-dimensional impacts on defined impact categories/criteria.

The impact indicators have been extracted, through focus groups with expert actors, and take into account the multidimensional impacts (economic, social, environmental, and cultural) on the wider territorial area according to the systemic perspective of the landscape proposed in the UNESCO recommendation on the historical urban landscape [87,88]. The categories of impact/criteria are i. Tourism and recreation; ii. Creative, cultural and innovative activities; iii. Local typical productions; iv. Environment and natural capital; v. Social and community cohesion, vi. Real estate; vii. Financial performance; viii. Welfare; ix. Cultural value of the property/landscape, which have been identified in relation to the general objective aimed at increasing productivity in more dimensions of the territory interested [89].

A judgment matrix was then elaborated with pairwise comparisons between the different alternative functions with respect to each indicator. Impacts of each function on each category of indicators were determined starting from the qualitative judgments expressed using the seven semantic categories of MacBeth (no impact; very weak; weak; moderate; strong; very strong; extreme).

After the phase referring to each fundamental criterion and to the attribution of the weights, the final aggregation phase was elaborated and a final classification of preferences was elaborated in relation to the general objective. Below, the MacBeth scale represents the final classification of the impacts that each option/function has on the criteria.


The group of experts (entrepreneurs, investors, and professionals in the real estate, tourism, and cultural heritage sectors) subsequently interacted and combined the various selected functions (among those that were compatible) and designed four adaptive reuse scenarios, representative of potential changes in current use on the economic, social, environmental and cultural plan.

### 3.2.2. EVAMIX Implementation of the Method

In relation to the chosen functions and in order to assess the suitability for adaptive reuse of the six selected forts, four potential reuse scenarios have been implemented. These scenarios represent the potential uses that can be successfully hosted in the military fortifications in question. The scenarios are the result of the combination of the functions selected through the MacBeth Method [72,73,73].

In relation to each decision scenario, the six alternative buildings have been evaluated and classified from the most to the least suitable for use in relation to each scenario, based on the criteria chosen based on the characteristics of the alternatives to be evaluated.

To structure the EVAMIX decision process [76–79] we proceeded according to the following phases:

Step 1. Identification of the assessment scenarios. Four different scenarios have been designed by the group of experts, as a result from of the integration of multiple functions chosen among those classified and judged most suitable and representative of potential changes in term of economic, social, environmental and cultural terms development. The following scenarios represent real and potential uses that can be successfully hosted in abandoned fortifications:


Step 2. Construction of the criteria tree. The set of criteria used in the evaluation process was formulated by a focus group of experts including entrepreneurs, investors and professionals in the real estate, tourism and cultural heritage sectors, in which the different points of view were discussed. Subsequently the research group has elaborated and translated the information in a limited number of criteria [68], clearly defined based on the characteristics of the alternatives to be evaluated, choosing above all the relevant ones (coherence with the objectives of the project) because a large number of indicators could make the evaluation process more complex and less effective.

The structure of the criteria considers the relevant aspects of the decision-making problem under consideration—environmental quality, economic aspects, context infrastructuring, and architectural features—in relation to the main strategic objective of the decision maker (DM) to create a new catalyst for the entire urban development process of the Strait area.

Step 3. Construction of the evaluation matrix. A 11×6 matrix characterized by mxn (eleven evaluation criteria x six alternative options) whose components are cardinal (quantitative) and ordinal (qualitative) data, which express the impact/performance of each alternative with respect to a given criterion. The evaluation matrix is shown in Appendix A.

Step 4. Criteria weighting. To assess the importance of the criteria, we made some interviews with the group of experts to indicate the weights for each of the criteria. Then AHP method was therefore implemented of the comparison in pairs [68,75], through the use of the "Saaty scale," to establish priorities (weights) and compare pairs of elements of each level with respect to a criterion in the next higher level. During the brainstorming process, with the help of a moderator, the experts reached consensus on the final set of weights.

The overall set of weights of criteria and sub-criteria is displayed in Appendix A. Note that, in the evaluation matrix, the values enclosed in round brackets are weights assigned in the AHP assessment [68,75].

Step 5. Classification of alternatives. In order to obtain the priority vectors and the final ranking, the EVAMIX method was implemented in the Definite 2.0 software [85].

In order to classify the adaptive reuse alternatives with respect to each scenario, it was simulated the investment decision of potential Decision Makers (DM) who expressed their expert judgment [90]. To this end, on the basis of their relevant experience and strong interest in the reuse of historical-cultural buildings, the group of experts was asked to identify which of the four adaptive reuse scenarios is the most suitable for the six alternatives of historic fortifications under study.

The results and the ranking order of alternatives are discussed in the following section.

### **4. Results and Discussion**

Figures 4 and 5 show the overall values of the EVAMIX assessment and the ranking of alternatives for the different uses considered in the study. According to the results obtained, alternative 1. Poggio is the most suitable building to be reused for different purposes and scenarios considered: Design Center, Artistic/Cultural Park, Health and Wellness Center, and Food Farm.

**Figure 4.** Evaluation of Mixed data (EVAMIX) method: overall value for the different scenarios.

**Figure 5.** EVAMIX method: ranking of the alternatives for the different scenarios.

From the results obtained, it is possible to say that the "1. Poggio" alternative is the best alternative for three out of four scenarios. The alternative "2. Siacci" also has excellent performance, since it is classified as the best alternative for the scenario: Health and Wellness Center and as the second best alternative for the scenarios: Design Center, Artistic/Cultural Park, Agriturismo. Furthermore, it should be noted that the "Beleno" is the alternative classified as the worst alternative in three out of four scenarios.

This result is influenced by the greater weight (relative importance) attributed by the experts to the criterion "Project Sustainability" (relative to the indicators: Degradation level, architectural characteristics and Flexibility of spaces to new functions, Total property availability), which in relation to the potential for reuse are of great importance [91] (Appendix A).

After obtaining a classification of alternatives and checking the consistency obtained in the results, it is useful to carry out a sensitivity analysis on the final outcome of the model. Sensitivity analysis concerns a type of "what if" question, which allows us to check if the final answer is stable when the model inputs are changed. It is of particular interest to see if these changes change the order of the alternatives.

In the present study, sensitivity analysis was performed regarding the weights of the criteria. In particular, the weight of one criterion at a time was increased up to 60% while the weights of the other criteria were kept equal to 20%. The evaluation model was performed considering again the weights and the final priorities of the alternatives were recalculated.

The Figure 6 represents the results of the sensitivity analysis performed. As can see, three alternatives—Poggio, Siacci, and Pentimele—have the best performances among the scenarios considered, while the Beleno alternative is ranked last.

### **5. Conclusions**

This document proposes a methodology that integrates different multi-criteria evaluation methods to support the decision-making process regarding the choice of sustainable alternative functions, aimed at the adaptive reuse of the historical-cultural heritage [92]. This theme is of particular importance because the phenomenon of the reuse of unused or abandoned historical and cultural heritage is becoming increasingly important, especially in Italy, where there are thousands of architectural quality assets that constitute a real resource for the territory.

The multi-criteria decision support method uses qualitative and quantitative criteria to evaluate four different reuse scenarios for the redesign of the "Forti Umbertini" system located in Southern Italy. The different scenarios were designed by a group of experts who also assigned the weights to the different criteria involved in the evaluation model.

The nature of the public goods considered by the enhancement projects and the strong articulation that characterizes the territorial redevelopment projects require complex approaches.

The application developed in the present study proved to be very advantageous, especially when planning interventions, to support complex decisions, about alternative scenarios, in which it is necessary to make a choice regarding alternative scenarios that take into account different points of view and the involvement of experts in the evaluation process.

For this purpose, the evaluation process was structured in order to incorporate the participation of all stakeholders in defining a "shared solution" capable of meeting the needs of the local community, and at the same time being sustainable over time from an economic point of view.

The methodological approach based on the integration of participatory processes and the multi-criteria analyzes, in a proposed multidimensional perspective, allowed to include the opinions of the stakeholders in the decision-making process. In this study, the involvement of the local community is one of the key factors for the success of this type of process and represented a fundamental support for the decision-making process. The integration between the community and specialist knowledge guarantees a higher level of acceptability of the results, reaching greater consensus, outlining strategies that are as shared as possible. It helps guide strategic choices better. The involvement of all stakeholders and actors facilitated the acquisition of information and knowledge that supported the decision-making process; it also ensured credibility and transparency in the process. In addition, this integrated evaluation process, in addition to considering the point of view of the various stakeholders, has enabled the generation of alternatives (possible functions) to be considered. Through the participation of all interested parties, the implementation and integration of multi-criteria methodologies, it was possible to define a "shared solution" and obtain a ranking of the alternatives for each decision scenario.

According to the results obtained, the "Poggio" alternative is the most suitable building to be reused for different purposes. This is due to the fact that the building is in good condition and the space configuration is very flexible to accommodate new and differentiated functions. The "Siacci" alternative contains the best features to be reused as a Health and Wellness Center due to the possibility of a large area that can be used for complementary functions. On the contrary, the "Beleno" alternative is classified in the last position in all the decision scenarios considered.

The results obtained, validated by the sensitivity analysis, are consistent in defining the most suitable building for adaptive reuse with respect to specific uses.

This study could have interesting implications, as it could represent a useful tool for policy makers in the process of planning and designing a general plan aimed at re-launching and enhancing the immense heritage with a view to creating a circular economy and promoting the economic development of the territory under investigation [93].

Today, the new challenge for local authorities is to regenerate abandoned heritage buildings while involving various stakeholders and the local community in order to create new governance models that are able to guarantee economic sustainability and conservation of values of historical and cultural heritage [94–96], as in the case of the "Forti Umbertini" under study, which have always been a symbol for the Strait community.

According to this perspective, future research in this field can be oriented towards the search for new management models, based on the concept of "heritage as common goods" [97–99], based on agreements between public promoters and Profit or No-Profit associations for the management of common goods [95,96].

**Funding:** This research received no external funding.

**Conflicts of Interest:** The author declare no conflict of interest.



### *Sustainability* **2020** , *12*, 1363
