**2. Material and Methods**

## *2.1. The Integrated Decision Support System for the Choice of Alternative Functions*

The redevelopment of heritage buildings is a complex design problem, in which several points of view need to be managed in a holistic evaluation process.

Following the classical approach proposed by Simon (1972) to the decision-making process, an integrated methodological framework was developed for this case study, as Figure 1 illustrates.

Simon defines three main stages of the decision-making process:


**Figure 1.** Methodological framework.

Starting from the main stages proposed by Simon, different evaluation methods have been proposed in order to support the definition of different reuse alternatives in redevelopment projects, including both technical problems related to the design projects [21–23,25], social issues, and financial feasibility. In the stated methodological framework, different multicriteria methods are combined with a financial model in the diverse stages of the decision-making process in order to develop a tool to enhance the quality and trustworthiness of the decision-making process itself.

The methodological framework is illustrated in Figure 1.

In the first stage of the decision-making process, the decision maker (DM) identifies problems, opportunities, and objectives regarding the reuse project of the heritage building. To accomplish this, a list of criteria was identified. The list of criteria was structured based on appropriate reference [26], which identified the main categories of analysis, but considering the peculiarity of the case study, this also emerged in a focus group with the public administration and the technicians.

Moreover, a map of relevant stakeholders was defined in accordance with the strategic objectives of the public administration oriented toward the valorization of the building as having symbolic value and being a meeting place for the local community.

Then, in the design phase, five alternatives were identified during a focus group organized by the municipality with the experts (architect, economist, and sociologist) and politicians.

The alternative solution was evaluated by means of a multicriteria method considering two types of analysis, namely a "technical evaluation" linked with the DM's preferences and a "social evaluation" linked with the stakeholders' points of view [27,28].

The technical evaluation was developed with the aim of defining a rank order of alternatives, considering the list of criteria previously defined with the help of two multicriteria methods, namely, regime analysis [29] and the weighted summation method (WSM) [30].

The regime method is used to start a dialogue between the DM and the experts, which has the advantage of simplifying the debate with the DM: at the beginning, he often does not have a clear idea of the problem and is not familiar with the decision-making tools. The regime method is a discrete multicriteria method with a partial compensatory structure based on pairwise operations. This method can handle mixed types of information, that is, both quantitative and qualitative. The fundamental input data are the impact matrix and the political weights, and these two elements are combined to calculate the probability that one alternative is preferred over another. The impact matrix includes the evaluation of each alternative with respect to each criterion. The set of weights is a qualitative assessment consisting of an ordinal evaluation of the criteria reflecting the DM's preferences.

Weighted summation is then used to check the previous results through the improvement of the set of weights: it regards a more complex process based on the pairwise comparison of the decision criteria. In this part, the main information is provided for better comprehension of the problem, the opportunities, and the potential of the alternative projects. Weighted summation is a compensatory approach based on a linear model. This method uses an indirect approach, in which the qualitative information is first transformed into cardinal information to be compared; this procedure is called "normalization" and it is necessary to handle different types of attributes. The input data are the impact matrix and the matrix of weights. The evaluations of each alternative with respect to each criterion are combined through the matrix of weights in one overall value, obtained by the addition of all the weighted scores together. The combination of the two previously described methodologies encourages a transparent dialogue between the public administration, which owns the building, and the architects in order to define a sustainable solution taking into account the different dimensions involved. Moreover, the methodologies proposed are included in the Definite software, which makes communication easier among different actors.

The Definite program was developed by Ron Janssen and Marine van Herwijnen in 1987 [31]. It is a multiobjective decision support system that supports the whole decision process from problem definition to report generation. The system performs the following functions: (1) structure the problem and generate alternatives; (2) compare alternatives; (3) rank and/or value alternatives; (4) support interpretation of the results; (5) present results. To perform these functions, the system contains five modules. Each module contains a variety of procedures (like the regime and weight summation methods) to perform these functions.

The social evaluation was developed with the aim of understanding the possible coalition generated by the choice of the best alternative [32,33]. This analysis was carried out with the help of the Novel Approach to Imprecise Assessment and Decision Environments (NAIADE) method [34]. The NAIADE method captures the preference of stakeholders and supplies indications of the distance of positions among the different interest groups. It evaluates the social compromise solution through the analysis of the possible coalitions. The NAIADE method is a discrete social multicriteria method, which includes mixed types of information and a conflict analysis in a fuzzy environment. Through pairwise linguistic evaluation, "based on semantic distance between linguistic qualities", two types of evaluation are provided. The first regards the assessment of the alternatives based on the social impact matrix, which contains a qualitative evaluation of each alternative with respect to a defined set of criteria, based on the stakeholder's preferences. The second analysis is performed by the completion of an equity matrix, where a similarity matrix is calculated. It sheds light upon the level of decision conflicts among the different interest groups and highlights the possible formation of coalitions (building a dendrogram of coalitions), showing the impact of each alternative as perceived by the social actors. In this way, NAIADE provides the following information: (a) distance indicators between the interests of the different social actor groups, as an indication of coalition formation possibility or interest convergence; (b) rankings of alternatives for every coalition, in accordance with the impacts on the social groups or the social compromise solution.

Then, the preferred alternative is developed, and the financial feasibility is evaluated. The method combines different assessment phases with sequential checks. This kind of structure allows the creation of an interactive framework able to incorporate the ideas of learning processes and the engagement of different stakeholders. These characteristics may provide better-informed decisions and a greater level of consent.

Multicriteria decision analysis (MCDA) can handle the complexity of the whole process. The MCDA methods provide tools for gauging stakeholders' preferences, comparing alternatives, and supplying useful indications to the DM [35]. From this perspective, MCDA has the principal aim to "create" instead of "find" solutions; therefore, it is a "constructive" approach [36].

Multicriteria analysis has the ability to compare the alternatives according to various conflicting stakeholder interests. The ability to involve several points of view in the early stage of the design problem through a participative process may help to avoid conflict and make more successful and transparent decisions [37,38].

Actually, the evaluation process is not a "one-shot activity"; instead, it is a constructive, dynamic process that advances in relation to continuous reinforcing gains along the various steps [39–43].
