Regenerative Design of Archaeological Sites: A Pedagogical Approach to Boost Environmental Sustainability and Social Engagement

: Sustainable pedagogical approaches and practices have changed during the years, generating a set of philosophical, theoretical, and scientiﬁc concepts. Inside them, regenerative design is a proactive method based on systemic frameworks and developmental processes for maintaining the integrity of natural ecosystems, also enhancing human life, environmental awareness, social equity, and economic sustainability through the support of codesign techniques. This approach is widely used in architectural design, both for existing and heritage buildings, to address negative impacts of global warming, climate change, urban sprawl, touristic pressure, and other contemporary challenging phenomena. Speciﬁc workﬂows for archaeological sites have been never proposed, despite the fact that these sites face problems and risks completely different from other cultural heritage settings (e.g., physical development, pollution, tourism pressure, vandalism, looting, inappropriate excavations or interventions, lack of maintenance, funding, and legislation). This study presents a multicriteria decision analysis workﬂow for preserving and regenerating archaeological sites in a sustainable way through a deep understanding of current problems, values, features, and risks at urban and building levels. This method is tested with a pedagogical experiment at the UNESCO Site of Casterseprio (Italy), to investigate the interaction between heritage, environmental, social, and economic dynamics as well as to deﬁne its feasibility, applicability, limitations, and opportunities for further developments. The didactic process is supported by a participatory program among the key players of the site (owners, heritage and public authorities, and local associations), to create strong public support and a shared vision of the sustainable regeneration of the area. Differences between traditional and regenerative design processes, key design principles, shared criteria, repli-cability, novelty, and limitations of the pedagogic approach are also identiﬁed. Key ﬁndings of the present study are: (i) students need clear and shared design workﬂows for supporting their design projects; (ii) “ regenerative design ” involves multilevel dynamic training methodologies that motivate and involve the student while also improving their consciousness; (iii) the cooperation and the involvement of the stakeholders is important to favor a human-centered approach based also on social and economic interactions; (iv) digital technologies are fundamental for quantifying the key performance indicators in each design stage; (v) “ regenerative design ” boosts long-term planning and ﬁnancial self-sustainability of the intervention; and (vi) multicultural design teams producing more innovative design ideas


Introduction
Sustainable development at the European (EU) level is supported through different policies at urban and building levels.Urban strategies boost energy transitions, carbon neutrality, affordable and clean energy, reduction of greenhouse gas emissions, biodiversity, climate mitigation, and adaptation [1][2][3].Similarly, building actions focus on energy efficiency, renovation, and decarbonization [4][5][6][7][8].This legislative framework underlines the importance of heritage conservation for safeguarding, enhancing, and transmitting the memory of a community for present and future generations [9][10][11].Cultural heritage is considered a key component in several EU conventions dedicated to sustainable development [11,12].The United Nation Educational, Scientific and Cultural Organization (UNESCO) considers culture as important as human rights, equality, and sustainability [13].The EU "Green Deal" [1] and the United Nations (UN) [14] highlight its role for favoring resilience, climate adaptation, safety, and sustainability [14].Moreover, the "Paris Climate Agreement" recognizes the positive contribution of traditional building techniques for climate adaptation [2], thanks to the use of natural sources [15,16], local, raw, and durable materials [16,17] that require low energy for production, transportation, and recycling.Furthermore, cultural heritage should be subject to special protection in spatial planning: generally, the monument is preserved, but its surroundings support the historical value and the functioning of the object.Thus, their protection is fundamental for preserving the natural and heritage values [18].
Sustainable development is divided in two streams: "technological sustainability" based on technical and engineering aspects, and "ecological sustainability" based on ecology and living systems principles [19].According to these two approaches, sustainable practices and didactics have changed over the years, generating a set of philosophical, theoretical, and scientific concepts [20][21][22][23][24][25][26][27][28][29][30][31].Each approach has specific definitions, principles, and criteria.First, the "biomimetic approach" looks to nature as inspiration for designing products and processes [25,26].Biomimetic technologies derive from natural models at nano and macro scales, considering their self-evolution for solving engineering problems with tolerance, resistance, and resilience [25].Similarly, "biophilia" creates a literal or evocative connection between nature and the human-made context to positively influence living systems, personal fulfillments, and processes [20,22].Biophilic design is used both at urban and building levels, suggesting the following principles: (i) direct connection with nature and environmental features; (ii) inspiration from biomorphic forms and patterns; (iii) presence of water; (iv) dynamic and diffuse light and huge spaces; (v) thermal and airflow variability; (vi) presence of nonrhythmic sensory stimuli and rich sensory information; and (v) place-based relationships.Then, "sustainable design" is characterized by a neutral environmental impact.Their key principles are widely diffuse in urban planning and architectural practices, such as (just to cite some common concepts) [32]: (i) site potential optimization; (ii) minimization of nonrenewable energies; (iii) use of environmentally friendly materials and low environmental impact products; (iv) protection and conservation of water, energy, and materials; (v) enhancement of indoor and outdoor environmental quality; and (vi) optimization of operational and management practices.More recently, this approach has shifted into "restorative design" to reconnect people to nature thanks to the renovation of social and ecological systems [20,22,24,25].Basilar principles concern the use of natural sources, renewable energy, and sustainable systems (optimization of natural light, energy systems, water, and materials) [22].This approach is more integrated with the environment than the biomimetic one as it tries to optimize natural resources and patterns [25].In addition, it is more active than "biophilia" as it evolves over time [25].Otherwise, it ends when the system acquires the capacity to self-organize, assuming that it can be infinitely adapted to external modifications [25].These ecologically based approaches try to stop degeneration processes and reduce their negative effects, focusing primarily on the initial environmental footprint [26].More recently, the idea of "regenerative design" [25,27] was introduced as a "living systems approach" [27], to create a positive interaction between built, human, and natural systems for promoting restoration, renovation, and revitalization of the built environment [26,28].It is a proactive approach based on systemic frameworks and developmental processes for maintaining the integrity of natural ecosystems, also enhancing human life, environmental awareness, social equity, and economic sustainability [20,25].The "regenerative design" approach is based on a long-term prospective [29].Fundamental principles are: (i) understanding places and their unique patterns (e.g., wind, water, energy, traffic flows); (ii) design for harmony with place; and (iii) co-evolution for the continuous adaptation of the project to external modifications.Inside this approach, the concept of "regenerative heritage" focuses on the protection and the revitalization of local history and knowledge [30,31].This idea is different from "restorative heritage" that requires the adaptive reuse of heritage buildings through the improvement of their accessibility, flexibility, and functions' hybridization [31].
Regenerative design is widely used in urban planning and architectural design to reconnect people with the natural environment, addressing negative impacts related to global warming, climate change, urban sprawl, touristic pressure, and other contemporary challenging phenomena for environmental preservation, and human wellbeing.This approach is applied especially for the regeneration of existing cities and buildings.Inside them, various methodologies have been published for boosting the regeneration of herit-age buildings [33][34][35] and sites [36][37][38].These methods consider both technical processes [33,35,35,38] and social needs [34,37,38] for favoring building resilience and retrofit.Re-generative design is used mainly to achieve environmental resilience in heritage building preservation and to reduce building damage from natural hazards, human habits, and climatic changes [33,36].Furthermore, economic and social regeneration approaches are introduced to improve the livability and the touristic attraction of rural [34] or inhabited [37,38] heritage areas.Finally, regenerative design is applied to the energy retrofit of herit-age buildings, especially for reaching net-zero energy targets [35,35].In addition, these workflows are supported by the use of innovative technologies [33,36] and codesign tech-niques [34,37,38].Previous studies focus on traditional (or rural) and heritage (or listed) buildings as well as historical towns.These workflows and models cannot be applied to archaeological areas, as they face problems and risks completely different from other cul-tural heritage settings.Moreover, specific workflows for the regenerative design of archae-ological sites have been not realized.
Archaeological sites express human, social, and technical development through the embodied values associated with civil, historic, artistic, spiritual, symbolic, educational, natural, ecological, and economic practices.They are composed by tangible (e.g., history, structures, physical state, and constrains) [39][40][41] and intangible heritage (i.e., meanings, traditions, philosophies, representations, and rituals) [42,43].Their preservation is faced with several risks connected to physical development, pollution, tourism pressure, vandalism, looting, inappropriate excavations or interventions, lack of maintenance, funding, and legislation [44][45][46].Physical development has certainly had major impact on their disruptions and changes, as it is directly connected to settlement expansion and infrastructure growth [42] and is indirectly associated with pollution, mass tourism, and social engagement [10,46].These aspects may also have a negative impact on the biodiversity of the area, not only on heritage resources [42].Hence, their efficient conservation refers to social wellbeing, responsibility, people's engagement, and respectful economic growth [47].Regenerative design can help them to face the effects of climate change, environmental and heritage despoliation, and land expansion in a resilient way.Thus, the main challenges for their revitalization refer not only to heritage (e.g., heritage preservation, enhancement, and management), but also to environmental (e.g., sustainable development, biodiversity preservation, use of resources, and improvement of local resources and systems), social (e.g., touristic attraction and people's engagement, wellbeing, training, and education), and economic (e.g., benefits, profits, and innovation) issues [42].This embodies a robust interrelation within the three pillars of sustainability: environment, society, and economy [19].The novelty of this research concerns the development of a specific workflow for the regenerative design of archaeological sites, considering their peculiarity, problems, and risks from a long-term perspective.Furthermore, its application to a pedagogical process at a higher education institution allows understanding of its feasibility, limitations, and opportunities for further development.

Aims
The study aims at defining a multicriteria decision analysis workflow for preserving and regenerating archaeological sites in a sustainable way through a deep understanding of current problems, values, features, and risks.This workflow is based on the multicriteria and transdisciplinary method to avoid resources' depredation; prevent heritage and environmental degradation; and create livable, safe, accessible, secure, and comfortable places [23,25].To improve the effectiveness of the regenerative paradigm, this method has been tested at the architectural Design Studio of the Polytechnic of Milan for the regenerative design of the Italian World Heritage Site of Castelseprio.Design studios are creative learning spaces where students can cooperate, brainstorm, and learn by doing [48], and where students and teachers work together to find design solutions for real-life situations [49].Based on this pedagogical approach, 54 international students worked in teams to solve the most important challenges in the area, presenting different regenerative design project ideas.
The key question at the basis of the work was: "How can design regenerate an archaeological area with positive environmental, social, and economic impacts, also conserving original features, values, materials, and biodiversity through cleaner energy production?"This goal is broken down into five subobjectives: (i) codification of shifts and differences between traditional and regenerative design processes; (ii) identification of a set of shared criteria to support designers and public and heritage authorities in the development and assessment of regenerative design plans; (iii) support for local decisionmakers through long-term planning, active contributions, and collaboration with the stakeholders; (iv) definition of limitations and opportunities for further development of the workflow through the application of a real case study; and (v) creation of a coherent design-oriented approach for supporting the architectural design projects of higher education, also fostering the sense of belonging among urban stakeholders.
The study is divided in two sections: • Methodology definition.
• Case study application.

Methodology Definition
Despite the fact that several "regenerative design" theories have been developed, their approach is based on three common theoretical stages [19]: (i) to "understand the relationship to place"; (ii) to allow the "designing for harmony with place"; and (iii) to obtain the "coevolution" of the design project.The present workflow connects these theoretical stages to three corresponding practical activities: • Phase 1: Analysis of "understand the relationship to place".
• Phase 2: Design to allow the "designing for harmony with place".
• Phase 3: Education to obtain the "co-evolution" of the design.
Then, these activities are integrated with the actions defined by the Whole Building Design Guide (WBDG) [50] to consider the heritage features of the archaeological site, and specifically: identify, investigate, develop, execute, and educate.Finally, the process must be revised and restarted [31].The scheme is reported in Figure 1.

Phase 1: Analysis
The analytical phase is structured in two subactivities:

•
Identification of the main characteristics of the archaeological site at landscape, urban, and building levels.
• Investigation of the relationships between physical, natural, human, and economic systems.

Phase 1: Analysis
The analytical phase is structured in two subactivities:  Identification of the main characteristics of the archaeological site at landscape, urban, and building levels.


Investigation of the relationships between physical, natural, human, and economic systems.

Identification
Past, current, and future evolutions should be analyzed for identifying the main characteristics of the archaeological site [50] as a living system [19], prioritizing long-lasting effects to design advanced human and natural systems [30].This approach requires deep and reiterated mapping and understanding of heritage, environmental, social, and economic dynamics and interactions [25].To simplify the complexity of archaeological systems, this assessment is structured in two subphases: Data collection is based on the survey, a basic technique for identifying and documenting cultural and natural heritage resources.In this case, the survey looks at a wide range of patterns, covering multiple scales and different facets to boost the empathetical imagination for the architectural design project [19].According to [12,14], the survey is divided into heritage, environmental, social, and economic factors.Heritage and environmental factors are inextricably intertwined [42].They refer to historical, architectural, scientific, social, spiritual, and linguistic qualities and attributes possessed by landscapes, places, buildings, and artefacts [39].These values should be associated both to tangible and intangible qualities [43].Social aspects refer to the possible engagement of people and to the impact of the regeneration design on human needs [36].Economic aspects concern the economic benefits of the process.Data collection should be supported by the following techniques: (i) archival research; (ii) urban data analysis; (iii) statistical data analysis; (iv) grey literature analysis; and (v) field investigation.The traditional heritage survey is

Identification
Past, current, and future evolutions should be analyzed for identifying the main characteristics of the archaeological site [50] as a living system [19], prioritizing longlasting effects to design advanced human and natural systems [30].This approach requires deep and reiterated mapping and understanding of heritage, environmental, social, and economic dynamics and interactions [25].To simplify the complexity of archaeological systems, this assessment is structured in two subphases:
Data collection is based on the survey, a basic technique for identifying and documenting cultural and natural heritage resources.In this case, the survey looks at a wide range of patterns, covering multiple scales and different facets to boost the empathetical imagination for the architectural design project [19].According to [12,14], the survey is divided into heritage, environmental, social, and economic factors.Heritage and environmental factors are inextricably intertwined [42].They refer to historical, architectural, scientific, social, spiritual, and linguistic qualities and attributes possessed by landscapes, places, buildings, and artefacts [39].These values should be associated both to tangible and intangible qualities [43].Social aspects refer to the possible engagement of people and to the impact of the regeneration design on human needs [36].Economic aspects concern the economic benefits of the process.Data collection should be supported by the following techniques: (i) archival research; (ii) urban data analysis; (iii) statistical data analysis; (iv) grey literature analysis; and (v) field investigation.The traditional heritage survey is based on archival research, urban and statistical data analysis, and field investigation [37,38].Archival research and data analysis techniques provide information on heritage and environmental items, thanks to national and local records [17].Field investigations are kinesthetic experiences based on the interaction with physical and social environments, to understand the state of the art of the of the archaeological site through active and experiential learning [51,52].They permit appreciation of the area in a nonstructured way, increasing observational skills, contextual knowledge, and cognitive processes [51].Grey literature is derived from journalism and social analysis to collect up-to-date information on the territory thanks to internet sites, social media, and newspaper articles.Finally, contextual inquiries are field interviews with visitors and community stakeholders to analyze needs, activities, and flows [53,54].They are proposed for gathering a systematic survey of users' experiences from a long-term perspective [54].Following a nonexhaustive matrix for data collection in an archaeological site is proposed (Table 1).Data inventory contains all the collected information, documenting values, regulations, protection levels, conservation conditions, preservation priorities, etc. [17,51] with original maps, designs, sketch plans, photographs, and diagrams [37,38,50].Heritage data must be geo-referenced for localizing each aspect on distribution maps [50].

Investigation
The systematic investigation of these data aims at mapping the relationship among different variables for outlining risks, problems, hazards, needs, challenges, and opportunities for the regenerative design process [50].The proposed method is based on the evaluation of strengths, weaknesses, opportunities, and threats, also called SWOT analysis.This phase is fundamental for underpinning possible transformations; transmitting the knowledge of the past; and enhancing heritage values, biodiversity, and landscape design, as well as for generating economic and social opportunities [51].A matrix of specific elements to consider is delineated below (Table 2).

Opportunities Threats
Example of key questions based on analysis of these data are: "What are the dynamics and the relationships between environmental, social, and economic systems?", "Does the site need to change?", "What are the major issues for improving its performance?","How can positive values for the stakeholders and the local ecosystem be added?".These basic questions help professionals and heritage and public authorities in making informed decisions for planning, design, and management purposes.The SWOT analysis for the regenerative design process is a continual flow of matters through a living system [19], not a static configuration.Thus, it is important to repeat this investigation for each modification of the design process.

Phase 2: Design
The design phase is structured in two subactivities:

•
Development of key design principles and schemes.
• Execution to translate the key design principles into systemic designs, integrated plans, and construction processes.

Development
The deep knowledge of needs, risks, and priorities is the starting point for defining tailored interventions on buildings and landmarks [21].An interactive relationship among all the professionals involved in the design process is proposed for reducing project unknowns and change orders and helping in quality control [25].Consultation and people's engagement are fundamental for defining insights, key principles, and alternative solutions [21,25] as well as for minimizing operational energy demand, consumption, and carbon dioxide emissions [47].The generative cocreation methods normally used in social science are selected to structure heritage, natural, human, and economic systems in a dynamic way [52].Several methods can be used, but the most useful for inspiring creative design is the experience interview with designers, public and heritage authorities, owners, and local organizations [52,53] because it permits gathering technical aspects in a narrative way, managing the changes of the place in a conscious way, and negotiating design targets [25].This technique has a clear focus on users' experiences [52], without requiring the knowledge of psychological models, such as cards use (e.g., needs, emotion granularity, and wellbeing determinant cards), or scientific methods (e.g., UX Concept Exploration and day reconstruction method) [52].Following a nonexhaustive matrix of the items to discuss in codesign sessions is proposed to harmonize stakeholders' needs with the larger pattern of ruins, buildings, landscapes, infrastructures, and services, also improving the economic benefits of the area (Table 3).Note: = Data to be collected.

Execution
Many regenerative design projects fail to achieve an effective outcome for the absence of the systemic connections [19].For this reason, the proposed workflow is based on the Integrated Design Process (IDP), a transdisciplinary, open, conscious, and participatory method that considers "multifaceted systems thinking" from the beginning [29].The disciplines to be involved are at least urban planning, landscape design, architecture, engi-neering, restoration, agriculture, agronomy, geology, ecology, biology, climatology, physics, sociology, psychology, and economy [20,25].Regenerative design requires schematic designs (rough sketches and drawings that illustrate the basic idea), design developments (plans, prospects, sections, axonometries, and renderings that illustrated the design concept in detail), construction drawings (technical specifications, details, notes necessary for bidding, permit application, and construction), computer simulations (energy, daylighting, and computational fluid dynamics), and technical documentation (cost and time management, building quality control, and commissioning).The design process should be supported by urban and building green rating tools during the early stage for determining the sustainability level of the project [55][56][57][58][59].At the urban level, the Building Research Establishment Environmental Assessment Method (BREAM ® ) Communities (BREAM ® C) [60][61][62] results are the most indicated for evaluating heritage aspects in regenerative projects [63,64].At the building level, the Green Building Council (GBC) Historic Building Protocol is specifically realized for assessing heritage buildings [65,66].

Phase 3: Education
Education activities require on-site expositions, local workshops, and training opportunities for illustrating and discussing the design project with the stakeholders, also improving people's engagement to boost the regenerative design of the archaeological site.

Methodology Application
According to the Sustainable Development Goals (SDGs) n. 4, 7, 11 and 13 [9], this workflow has been experimented with at the architectural Design Studio of the Polytechnic of Milan to ensure adequate knowledge and skills for the learners for comprehending and responding to the challenges of sustainable development.Design studios are important experiences for developing architectural sensitivities, communicative abilities, and problemsolving skills for future architects [67,68].In this specific case, 54 students from several international countries (e.g., Italy, Germany, Poland, Spain, Canada, Brazil, China, India, Korea, Japan, Israel, etc.) worked in teams of 4-5 people on the same project.Professors helped them to solve specific design problems with theoretical and practical backgrounds.Training focused on legislation, architectural restoration (e.g., criteria, principles, working phases, and materials), technology of architecture (e.g., building materials, construction systems, and innovation in the building sector), and building physics (e.g., sustainability, energy efficiency, green design, renewable energy sources, lighting, and acoustic design).Furthermore, the design process was supported by the key players of the site (owners, local HA, province, municipality, and local associations), to create a shared vision of the sustainable regeneration of the area [50].

Phase 1: Analisys
The methodology was applied to the UNESCO site of Castelseprio, an archaeological area situated in the province of Varese inside the natural park of the "Olona River" (Lombardy Region).As introduced in the methodology framework, the analytical phase was divided into:
The results of each subphase are reported below.

Identification
The design project started with the collection and the inventory of a series of data relating to heritage, environmental, social, and economic characteristics.This preliminary study outlined urban and architectonic features as well as socio-economic characteristics.Data collection at urban and building levels was supported by archival research, urban, statistical, and grey literature data analysis, as well as by field investigations and contextual inquiries with the stakeholders (tourist, visitors, and staff).Urban data concerned:  Building data referred to an existing museum that requires a deep building retrofit and refers to: (i) history; (ii) shape, typology, and dimensions; (iii) materials and constructive technologies; (iv) microclimatic data; (v) heritage values and aesthetic design; and (vi) conservation and maintenance level.The information was synthetized and illustrated in specific relations and graphical studies on heritage, environmental, social aspects.The history of the archaeological site was reconstructed, discovering that the place reached as far back as prehistoric and protohistoric times, while several artifacts came from the Bronze and the Early Iron Ages.Its history was linked to the strategic position between road Novaria-Comum, a Roman road that connected the cities of Novara and Como.This position led the founding of a fortified citadel (called Castrum Sibrium) of the V-VI century.Most buildings were built in Byzantine and Medieval periods.Belonging to this period were both heritage (e.g., the Churches of Santa Maria Foris Portas, San Giovanni Evangelista, and San Paolo, the noble house, and the Torba Monastery) and vernacular buildings.Traditional houses and living quarters were designed as independent units, or multistory forms with similar typologies, but with different colors, finishing, and patterns.The citadel maintained its prestige during the Middle Ages (IX-XI Century), but it was destroyed in 1287 by the Archbishop of Milan, Ottone Visconti, to prevent its use by rivals.The first ruins were discovered in the XIX century around the passion of ancient buildings and collections.Then, deforestation activities revealed the presence of an old settlement (1944).The archaeological park was established in 1950 after continuous deforestation work, and excavation campaigns discovered several ruins and ancient objects.It became a UNESCO site in 2011, providing the experience of a medieval settlement (Figure 3).
Also, archival research, urban data analyses, and field investigations were important to recognize heritage values, typical constructive technologies, and traditional materials (Figure 4).Building data referred to an existing museum that requires a deep building retrofit and refers to: (i) history; (ii) shape, typology, and dimensions; (iii) materials and constructive technologies; (iv) microclimatic data; (v) heritage values and aesthetic design; and (vi) conservation and maintenance level.The information was synthetized and illustrated in specific relations and graphical studies on heritage, environmental, social aspects.The history of the archaeological site was reconstructed, discovering that the place reached as far back as prehistoric and protohistoric times, while several artifacts came from the Bronze and the Early Iron Ages.Its history was linked to the strategic position between road Novaria-Comum, a Roman road that connected the cities of Novara and Como.This position led the founding of a fortified citadel (called Castrum Sibrium) of the V-VI century.Most buildings were built in Byzantine and Medieval periods.Belonging to this period were both heritage (e.g., the Churches of Santa Maria Foris Portas, San Giovanni Evangelista, and San Paolo, the noble house, and the Torba Monastery) and vernacular buildings.Traditional houses and living quarters were designed as independent units, or multistory forms with similar typologies, but with different colors, finishing, and patterns.The citadel maintained its prestige during the Middle Ages (IX-XI Century), but it was destroyed in 1287 by the Archbishop of Milan, Ottone Visconti, to prevent its use by rivals.The first ruins were discovered in the XIX century around the passion of ancient buildings and collections.Then, deforestation activities revealed the presence of an old settlement (1944).The archaeological park was established in 1950 after continuous deforestation work, and excavation campaigns discovered several ruins and ancient objects.It became a UNESCO site in 2011, providing the experience of a medieval settlement (Figure 3).Also, archival research, urban data analyses, and field investigations were important to recognize heritage values, typical constructive technologies, and traditional materials (Figure 4).Furthermore, urban, statistical, grey literature analysis, and field investigations enabled the classification of environmental patterns and land uses.Contextual inquiries and spatial analyses supported the evaluation of users' needs in terms of activities, times, and their interactions (Figures 5 and 6).

Investigation
The SWOT analysis was conducted at urban and building levels to identify potentials and problems of the archaeological site.At the urban level, (Table 4) positive elements referred to the high historic and natural values, thanks to the presence of well-conserved settlements and high biodiversity.Negative elements concerned the presence of abandoned buildings and inaccessible ruins as well as of aged and low-maintained facilities and amenities (e.g., benches and fences).Although the site was covered in lush green, proper maintenance was lacking.Furthermore, the site was not fully accessible to public transport and for visitors with limited mobility.
At building level (Table 5), positive points referred to historic values, good conservation levels, passive energy strategies, and bioclimatic measures.Problems concerned the overlapping of functions, waste of spaces, segregation of visitors and archaeologists, and low human comfort performances.
This embodied knowledge was used to underpin the regenerative design process through the codesign phase for collecting suggestions, corrections, and discussions to improve the quality of the results.

Phase 2: Design
The design phase was illustrated from ideation and conception through planning, project proposal, and technical engineering.Codesign was supported by several hands-on trainings devoted to the exploration of the most important urban, architectonic, artistic, and social aspects involved in the design practice.Furthermore, a series of experience interviews with local HA, PA, archaeologists, and owners were realized, to collect more practical information.Keywords gathered before and after the codesign experiences were discussed in specific focus groups.Key design principles originated from their comparison (Table 6).Furthermore, urban, statistical, grey literature analysis, and field investigations enabled the classification of environmental patterns and land uses.Contextual inquiries and spatial analyses supported the evaluation of users' needs in terms of activities, times, and their interactions (Figures 5 and 6).Furthermore, urban, statistical, grey literature analysis, and field investigations enabled the classification of environmental patterns and land uses.Contextual inquiries and spatial analyses supported the evaluation of users' needs in terms of activities, times, and their interactions (Figures 5 and 6).

Investigation
The SWOT analysis was conducted at urban and building levels to identify potentials and problems of the archaeological site.At the urban level, (Table 4) positive elements referred to the high historic and natural values, thanks to presence of well-conserved settlements and high biodiversity.Negative elements concerned the presence of abandoned buildings and inaccessible ruins as well as of aged and low-maintained facilities and amenities (e.g., benches and fences).Although the site was covered in lush green, proper maintenance was lacking.Furthermore, the site was not fully accessible to public transport and for visitors with limited mobility.

Execution
Eleven design projects were realized according to the key principles of regenerative design discovered through the codesign process (Table 6).Heritage and environmental protection were the founding pillars of all projects.'Heritage conservation, enhancement, and management' started from the respect of the high value of ruins, old buildings, archaeological manufacts, and surrounding landscapes.Instead of demolition and redevelopment, the adaptive reuse of existing buildings and ruins was preferred to preserve their values.New additions were based on 'flexibility and adaptability' of spaces, infrastructure, structures, layouts, and furniture.Functional mix, multipurpose buildings, and flexible rooms for collective activities (e.g., meeting, training, education, association, shopping, gaming, exposition, etc.) were suggested to favor the exchange between visitors, staff, inhabitants, and associations.Similarly, structural modularity, and dry-construction systems made by lamellar wood or recycled iron were chosen for facilitating horizontal and vertical expansion.These ideas were strongly connected to 'reversibility and recognizability' criteria; to remove fastening systems, assemblies, and installation methods without any damage [69];

Phase 2: Design
The design phase was illustrated from ideation and conception through planning, project proposal, and technical engineering.Codesign was supported by several handson trainings devoted to the exploration of the most important urban, architectonic, artistic, and social aspects involved in the design practice.Furthermore, a series of experience interviews with local HA, PA, archaeologists, and owners were realized, to collect more practical information.Keywords gathered before and after the codesign experiences were discussed in specific focus groups.Key design principles originated from their comparison (Table 6).

Key-Design Principles Before Co-Design Experience After Co-Design Experience
The design phase was illustrated from ideation and conception through planning, project proposal, and technical engineering.Codesign was supported by several handson trainings devoted to the exploration of the most important urban, architectonic, artistic, and social aspects involved in the design practice.Furthermore, a series of experience interviews with local HA, PA, archaeologists, and owners were realized, to collect more practical information.Keywords gathered before and after the codesign experiences were discussed in specific focus groups.Key design principles originated from their comparison (Table 6).The design phase was illustrated from ideation and conception through planning, project proposal, and technical engineering.Codesign was supported by several handson trainings devoted to the exploration of the most important urban, architectonic, artistic, and social aspects involved in the design practice.Furthermore, a series of experience interviews with local HA, PA, archaeologists, and owners were realized, to collect more practical information.Keywords gathered before and after the codesign experiences were discussed in specific focus groups.Key design principles originated from their comparison (Table 6).

Green protocols
Green rating systems LEED BREAM Environmental needs were defined through the SWOT analysis for improving landslide defense, wind resistance, water supply, rainwater adsorption, human comfort, accessibility, and maintenance (Table 4).Nature-based solutions contributed to sustainability and resilience through the provision of ecosystem services, such as local climate control, air quality regulation, water purification, soil, and water retention.To this purpose, 'biophilia and landscape design' aimed at creating a direct contact between natural and built environments, increasing the permeability of artificial forest boundaries thanks to the design of new pathways, slope protections, and panoramic watching decks.Organic shapes, repetitive geometric flourishes, porous constructions, and warm earth tones, as well as local, natural, and recycled materials were selected.Similarly, 'environmental and water preservation' (e.g., control and treat stormwater, reuse and recycle water for on-site use) were considered important elements for supporting the relationship with nature.In a project, the rain garden tried to solve landslide susceptibility by capturing rainwater and reducing surface runoff.Here, superficial pebbles and sand favored the habitat of insects and the growth of roots.Plants were selected from native flora, to gradually allow the development of small biological communities.New structures and facilities were designed without heavy installations and impacts on soil, to be easily removed (Figure 8).'Accessibility and universal design' of the site were improved in different ways: smallscale electric car shuttle services from public transport nodes, absence of architectural barriers, flat areas (for playscapes, workshops, terraces, picnics, and bird watching), gentle slope pathways, shelters, benches, tactile signages, and surfaces.In addition, the sizing of pathways considered people flows by allowing bicyclists, pedestrians, and those with  'Accessibility and universal design' of the site were improved in different ways: smallscale electric car shuttle services from public transport nodes, absence of architectural barriers, flat areas (for playscapes, workshops, terraces, picnics, and bird watching), gentle slope pathways, shelters, benches, tactile signages, and surfaces.In addition, the sizing of pathways considered people flows by allowing bicyclists, pedestrians, and those with 'Accessibility and universal design' of the site were improved in different ways: smallscale electric car shuttle services from public transport nodes, absence of architectural barriers, flat areas (for playscapes, workshops, terraces, picnics, and bird watching), gentle slope pathways, shelters, benches, tactile signages, and surfaces.In addition, the sizing of pathways considered people flows by allowing bicyclists, pedestrians, and those with disabilities to travel through the area without interference.In one project, the roads around the site were also designed to allow the passage of emergency and maintenance vehicles.Heritage as economic resource was another pillar of the projects.Two main approaches were considered.First, 'emotional design' aimed at activating positive responses of visitors through new didactic and sensitive routes, appealing furniture, sensory involvements, user-friendly interfaces, effective visual elements, smart devices, and engaging contents (Figure 9).disabilities to travel through area without interference.In one project, the roads around the site were also designed to allow the passage of emergency and maintenance vehicles.Heritage as economic resource was another pillar of the projects.Two main approaches were considered.First, 'emotional design' aimed at activating positive responses of visitors through new didactic and sensitive routes, appealing furniture, sensory involvements, user-friendly interfaces, effective visual elements, smart devices, and engaging contents (Figure 9).Furthermore, the 'open-air architectural park' aimed at balancing heritage preservation, regeneration, and community-focused economic returns through an interactive and leisure-oriented approach for different touristic groups.To this purpose, interactive info points, systems for simulating the original form of structures, and pathways with storytelling were designed (Figure 10).Both approaches were based on a 'user-centered design' for understanding users' needs and objectives and to create a positive interchange with the local community (e.g., user participation into cultural activities, heritage associations, and local farm creation).This may generate economic benefits linked to the improvement of slow tourism, education activities, and creative industries.'Natural materials and circular economy' were used to ensure low levels of embodied and operational carbon emissions, and to reduce construction time.Disassembly strategies; flexible constructive schemes; demountable wall panels; and natural, raw, recyclable, and reclaimed materials (e.g., recycled plastic bottles, rice, wood, leather, bamboo, paper, and coconut fibers) were selected to minimize waste (Figure 11).Moreover, the re-appropriation of vernacular shapes, local materials, and techniques contrasted the globalization of the construction Furthermore, the 'open-air architectural park' aimed at balancing heritage preservation, regeneration, and community-focused economic returns through an interactive and leisureoriented approach for different touristic groups.To this purpose, interactive info points, systems for simulating the original form of structures, and pathways with storytelling were designed (Figure 10).Both approaches were based on a 'user-centered design' for understanding users' needs and objectives and to create a positive interchange with the local community (e.g., user participation into cultural activities, heritage associations, and local farm creation).This may generate economic benefits linked to the improvement of slow tourism, education activities, and creative industries.'Natural materials and circular economy' were used to ensure low levels of embodied and operational carbon emissions, and to reduce construction time.Disassembly strategies; flexible constructive schemes; demountable wall panels; and natural, raw, recyclable, and reclaimed materials (e.g., recycled plastic bottles, rice, wood, leather, bamboo, paper, and coconut fibers) were selected to minimize waste (Figure 11).Moreover, the re-appropriation of vernacular shapes, local materials, and techniques contrasted the globalization of the construction process.This may produce also economic benefits for the creation of long-term jobs and spillovers related to traditional craftsmanship.In parallel, waste management was crucial to characterize the livability and the functionality of the place.These strategies were applied at urban and building levels, in the last case both on existing buildings and new additions.
At building level, the key design principles of 'deep energy retrofit', 'integration of renewable energy', and 'human comfort and wellbeing' were considered as a whole element.In all the architectural projects, passive design, energy efficiency, and renewable energies strategies were adopted.The passive design approach harnessed all the potential advantages from the site, surroundings, and climate.For this purpose, bioclimatic internal layouts, sun and wind orientations, vegetal shading systems, evaporative cooling, daylighting, and natural ventilation were chosen.In parallel, energy efficiency strategies considered natural-based insulation materials, high airtightness, high performance glazing, task lighting with lighting sensors, mechanical ventilation systems with heat recovery, high-efficiency heating, ventilation, air conditioning (HVAC) systems, indoor set point temperatures, and integrated photovoltaic (PV) systems (e.g., colored and thin film PV) for reaching the self-sufficiency of energy consumption [70,71].Finally, green rating tools were used as design-support schemes for selecting different interventions during the design phase, to nail down every sustainability feature, and to maximize the environmental benefits.BREAM© C and GBC HB were respectively used at urban and building levels.process.This may produce also economic benefits for the creation of long-term jobs and spillovers related to traditional craftsmanship.In parallel, waste management was crucial to characterize the livability and the functionality of the place.These strategies were applied at urban and building levels, in the last case both on existing buildings and new additions.At building level, the key design principles of 'deep energy retrofit', 'integration of renewable energy', and 'human comfort and wellbeing' were considered as a whole element.In all the architectural projects, passive design, energy efficiency, and renewable energies strategies were adopted.The passive design approach harnessed all the potential advantages from the site, surroundings, and climate.For this purpose, bioclimatic internal layouts, sun and wind orientations, vegetal shading systems, evaporative cooling, daylighting, and natural ventilation were chosen.In parallel, energy efficiency strategies considered natural-based insulation materials, high airtightness, high performance glazing, task lighting with lighting sensors, mechanical ventilation systems with heat recovery, high-efficiency heating, ventilation, air conditioning (HVAC) systems, indoor set point temperatures, and integrated photovoltaic (PV) systems (e.g., colored and thin film PV) for reaching the self-sufficiency of energy consumption [70,71].Finally, green rating tools were used as design-support schemes for selecting different interventions during the design phase, to nail down every sustainability feature, and to maximize the environmental benefits.BREAM© C and GBC HB were respectively used at urban and building levels.

Phase 3: Educate
Stakeholders were involved in the design project from the beginning thought several workshops with PA, HA, and owners to present the design ideas.In addition, posters and wayside signals were exhibited in the archaeological sites for generating interest in the project fostering the heritage revitalization.

Discussion
Comparing with a traditional pedagogical approach, the regenerative design approach permits a complete overview of the site, considering not only urban and architectural issues, but also social, economic, natural, and heritage issues thanks to the integrated vision of different disciplinary fields.This methodology allows the definition of key

Phase 3: Educate
Stakeholders were involved in the design project from the beginning thought several workshops with PA, HA, and owners to present the design ideas.In addition, posters and wayside signals were exhibited in the archaeological sites for generating interest in the project fostering the heritage revitalization.

Discussion
Comparing with a traditional pedagogical approach, the regenerative design approach permits a complete overview of the site, considering not only urban and architectural issues, but also social, economic, natural, and heritage issues thanks to the integrated vision of different disciplinary fields.This methodology allows the definition of key design principles and shared criteria for the regenerative design of archaeological sites, as highlighted by the following points:

•
Deep understanding of past, current, and future evolutions of the archaeological site for identifying its risks, problems, and opportunities.

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Deep understanding of local socio-economic conditions for the success of the design project.
• Recognition and respect of history, authenticity, local identity, and meanings of cultural heritage for developing proper restoration, exhibitions, and training activities.
• Multifunctionality and flexibility as key actions for hosting a wider range of activities, visitors, and hybrid experiences.
• Improvement of accessibility and mobility connections for attracting a wider community.

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Reuse of abandoned buildings for introducing new imaginative functions.
• Reversibility and recognizability of new additions for preserving and respecting the original fabric.
• Sustainability, energy efficiency, renewable energy sources, and circular economy as fundamental principles for reducing greenhouse gas emissions.

•
Green design and biophilia as criteria for boosting the social revitalization of the area.

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Use of digital technologies (e.g., serious games, virtuality, and augmented reality) for preserving and transmitting stories, legends, and intangible heritage.
• Mutual cooperation between local community and public and private sectors for contributing to the revitalization of the neighborhoods.

•
Reinvestment of profits for continuative maintenance and management.
• Attractiveness of local craftsmen, creative enterprises, and innovative industries in training, research, and cultural activities on archaeological and natural heritage for creating economic spillovers (i.e., fashion, film production, etc.).
• Creation of employment opportunities in heritage and touristic sectors connected to archaeology (i.e., communication, education, tourism, food production, etc.) and development of cultural activities and events for obtaining economic benefits from visitors and local community.
• Appeal of the new intervention for incrementing local and circular tourism.

•
Offering dynamic educational and social activities for residents (not only for tourists).
Fundraising strategies for sponsoring heritage activities.
• Despite these aspects seeming common in a professional architectural design project, they are not usual for high educational design approaches [72].The students learnt to create complex connections among different disciplinary fields in a critical way, understanding that urban planning and architecture needs a "living systems approach" [27] based on a deep knowledge and a positive integration among built, natural, social, and economic systems [26,28].Some ideas are common to the concept of "regenerative heritage", such as improvement of flexibility, hybridization, accessibility, and mobility connections [31].Others relate to the concept of "regenerative design", such as the deep knowledge of heritage, built, and natural systems as well as of socio-economic conditions [25,27].Other ideas pertain to the concept of "restorative heritage", such as the adaptive reuse of heritage, the creation of creative industries, circular tourism, and employments opportunities [30,31].Finally, other ideas refer to "biophilia", such as the use of green design for regenerating a semi-abandoned area [25].Otherwise, the "biomimetic approach" [25,26] was not successful, as students prefer the recognizability of the intervention and the use of digital technologies for creating new experiences and products [33,36].Furthermore, codesign techniques were fundamental for inspiring new ideas [34,37,38].

•
This methodological approach has also several innovative aspects and benefits for the design process, such as: • Replicability of the workflow both for architectural education and practice.
• Creation of a strategic vision and transparent planning and design process.
• Logical and reasonable scheme and transnational criteria for the sustainable decisionmaking process.
• Simplification of complex factors facing archaeological sites and local heritage communities today.
• Synthesis and order among environmental, social, and economic information of the site.
• Bridge of traditional boundaries between social, economic, and environmental sciences and between research, practice, and policy.
• Design innovation focused on human needs and participation processes to integrate multiple and future perspectives.
• Reiteration of the evaluations during the design process.

Conclusions
The study presents a multicriteria decision analysis workflow for the regenerative design of archaeological sites.This systemic approach aims at creating a positive interaction between built, human, and natural systems, also enhancing heritage and natural environment, human life, social equity, and economic sustainability [20,25].This method is applied in the Italian UNESCO site of Casterseprio, to verify its feasibility for mapping the interaction between heritage, environmental, social, and economic dynamics in a real case study.The experiment was conducted inside a design studio of the Polytechnic of Milan to verify the applicability, feasibility, potentiality, and limitation of the workflow in the architectural learning process.This experience provided a positive simulation of the thinking methods that students will encounter in professional life [72][73][74].Some differences between traditional and regenerative design processes applied to an archaeological area can be underlined.First, "traditional design" is a linear process based on analytical, design, and educational activities, while "regenerative design" is a circular process based on a reiterate and dynamic interaction between analytical, design, and educational activities.This requires a continuous design process between teachers, students, and stakeholders, to verify the correctness of the design ideas.The students develop a major consciousness and knowledge about problems, needs, risks, and resources to be applied to the design project.Second, traditional and regenerative design considers heritage and environmental factors, while additionally "regenerative design" considers their social and economic interactions.This opens a new dimension for the project design, developing a human-centered approach that aims at involving local stakeholders in the design process through focus groups, interviews, surveys, registration, video production, and other tools normally used in social science.Furthermore, economic factors (not only the cost of the intervention) acquire importance, developing the idea that the architectural design projects on cultural heritage should also provide scenarios for gathering economic benefits for the architectural experience.Third, "regenerative design" favors the active collaboration with the stakeholders to boost long-term planning and financial self-sustainability of the interventions.These aspects improve the quality of the teaching, adding new concepts, new disciplinary fields, and a better interaction among teachers, students, and all the stakeholders involved in the codesign process.Moreover, these aspects improve the quality of the design project and of the learning process for the students, adding integrated design ideas and a good understanding of needs and limitations of the archaeological site thanks to the involvement of local stakeholders (e.g., heritage and public authorities, owners, and visitors).Otherwise, limitations concern the small sample size of the students.However, their international backgrounds provide a better understanding of the international mainstream related to design concepts.

Sustainability 2023 , 27 Figure 1 .
Figure 1.The proposed methodology for the regenerative design of archaeological sites (Author's elaboration).

Figure 1 .
Figure 1.The proposed methodology for the regenerative design of archaeological sites (Author's elaboration).
(i) historical, environmental, social, and economic development; (ii) environmental conformation and morpho-topological structure; (iii) climatic data; (iv) heritage and natural values; (v) legislative framework; (vi) conservation and maintenance levels; (vii) accessibility and transport systems; (viii) touristic aspects; (ix) human needs and activities; and (x) future provisions.The location of the building is reported below (Figure 2).

27 Figure 2 .
Figure 2. Map of the area (Source: Author's elaboration from Google Earth).

Figure 2 .
Figure 2. Map of the area (Source: Author's elaboration from Google Earth).

Figure 3 .
Figure 3.The history of the archaeological site of Castelseprio (Source: Design team composed of the students Jia Liao, Zhifeng Li, Patrycja Pisarek, Mengya Wu, and Lei Zuo).

Figure 3 .
Figure 3.The history of the archaeological site of Castelseprio (Source: Design team composed of the students Jia Liao, Zhifeng Li, Patrycja Pisarek, Mengya Wu, and Lei Zuo).

Figure 4 .
Figure 4. Abacus of typical constructive technologies of the main building in the archaeological site of Castelseprio (Source: Design team composed of the students Wei He, Huiyuan Jiang, Tong Li, Jingwen Shen, and Haoran Wu).

Figure 4 .
Figure 4. Abacus of typical constructive technologies of the main building in the archaeological site of Castelseprio (Source: Design team composed of the students Wei He, Huiyuan Jiang, Tong Li, Jingwen Shen, and Haoran Wu).

Figure 4 .
Figure 4. Abacus of typical constructive technologies of the main building in the archaeological site of Castelseprio (Source: Design team composed of the students Wei He, Huiyuan Jiang, Tong Li, Jingwen Shen, and Haoran Wu).

Figure 6 .
Figure 6.Interactions among the activities of different users in the archaeological site of Castelseprio (Source: Design team composed of the students Wei He, Huiyuan Jiang, Tong Li, Jingwen Shen, and Haoran Wu).

Figure 6 .
Figure 6.Interactions among the activities of different users in the archaeological site of Castelseprio (Source: Design team composed of the students Wei He, Huiyuan Jiang, Tong Li, Jingwen Shen, and Haoran Wu).

Table 1 .
Matrix for data collection in an archaeological site (source: Author's elaboration).
Note: = Data to be collected.

Table 2 .
Matrix for the archaeological site evaluation through the SWOT analysis (source: Author's elaboration).

Table 3 .
Matrix for defining the items to discuss in the codesign working tables of an archaeological site (source: Author's elaboration).

Table 4 .
Application of the matrix for the SWOT analysis to the UNESCO archaeological site of Castelseprio at urban level (source: Author's elaboration).

Table 4 .
Application of the matrix for the SWOT analysis to the UNESCO archaeological site of Castelseprio at urban level (source: Author's elaboration).

Table 5 .
Application of the matrix for the SWOT analysis to the archaeological site of Castelseprio at building level (source: Author's elaboration).

Table 6 .
Keywords and key design principles for the regenerative design of the archaeological site of Castelseprio (source: Author's elaboration).

Table 6 .
Keywords and key design principles for the regenerative design of the archaeological site of Castelseprio (source: Author's elaboration).

Table 6 .
Keywords and key design principles for the regenerative design of the archaeological site of Castelseprio (source: Author's elaboration).