ReSeMM Project – Development of a multimodal sensor network for structural and environmental monitoring. Spoke 6, Intervention site Villa Romana di Realmonte, Agrigento
The project was carried out as part of the PNRR Spoke 6 public tender, Mission 4 “Education and Research” – component 2 “from research to business” – investment line 1.3 “Partnerships extended to universities, research centers, and companies for the financing of basic research projects” – research and innovation program “Changes – Creativity and Intangible Cultural Heritage,” funded by the European Union – NextGenerationEU.
The initiative involved, for the sites indicated in the call for proposals and in compliance with the instructions of the client and the local authorities responsible for protection, the design and supply of a multimodal sensor network and the creation of a cloud-based software platform, integrated with a geospatial database, capable of remotely managing the network, acquiring, storing, processing, and displaying the collected data in real time, and setting alarm thresholds.
The project, coordinated by the Department of Civil Engineering (DICIV) of the University of Salerno, with Prof. Luigi Petti as Scientific Director, also involved the Departments of Industrial Engineering (DIIN) and Cultural Heritage Sciences (DISPAC), together with the innovative start-up Modula S.r.l..
Objectives
Architectural and archaeological heritage is exposed to dangers and risks, not only natural and anthropogenic, but also climate change; added to this are the natural processes of degradation generated by the aging of materials and the variability of environmental conditions. With a view to the sustainable use of resources and heritage protection, the development of methodological approaches that promote minimal intervention and proactive maintenance plays a key role in the management process. The proposal aims to implement a model and an integrated multi-scale and multi-level monitoring network through the development of robust and expandable systems that guarantee constant monitoring of the state of health of the assets, allowing the behavior of the artifacts to be characterized, including the implementation of BIM models to document the life cycle of the structures and the development of predictive models.
The main purpose of monitoring the Roman Villa in Realmonte is to control and analyze the evolution of the deterioration affecting the archaeological area, in order to prevent irreversible damage and plan targeted conservation and restoration interventions. The critical issues identified include structural subsidence of the walls, detachment of wall coverings, and deterioration of the stone materials and decorations that characterize the most significant rooms of the villa. The monitoring system will allow data to be collected over time, providing a knowledge base useful for understanding the evolution of these phenomena and for planning preventive and corrective actions.
The Roman Villa of Realmonte, overlooking the bay of Punta Grande and nestled in a delicate stretch of the Agrigento coastline, is an archaeological site of great historical and scenic value. Its layout, featuring thermal baths, mosaic floors, and residential spaces, highlights the importance of the residence and the prestige of its owner during the imperial era. Direct exposure to atmospheric agents and the fragility of ancient materials make it necessary to constantly monitor environmental and structural conditions in order to prevent the progression of degradation processes that can affect mosaics, masonry, decorated surfaces, and above all, the rocky area that separates the villa from the beach. This is the context in which the monitoring project was conceived, designed to create a technological system capable of observing the physical, chemical, and biological phenomena affecting the site over time, collected in an integrated system that allows both data acquisition and remote processing through a centralized platform. The project is based on the desire to build a stable, continuous, and reliable network that can support the protection of the villa over the years by providing operators and specialists with accurate, up-to-date, and useful information for planning preventive or corrective measures.
Sensor network
The sensor network is the operational heart of the entire system. The choice of instruments was based on an analysis of the critical issues observed during the site inspection and the need to monitor two main areas: on the one hand, the mosaic of the thermal baths, an element of extraordinary artistic value but extremely sensitive to microclimatic variations and humidity, and on the other, the rocky face directly exposed to the sea, where erosion, heavy rainfall, and atmospheric agents can cause subsidence or landslides. In order to fully understand the processes affecting these areas, the sensor network has been designed to collect four broad categories of data: physical data relating to weather conditions such as temperature, humidity, solar radiation, wind intensity and direction, rainfall and air quality with parameters such as CO, SO₂, NO₂, ozone and fine particles; chemical data, useful for measuring the presence of pollutants and salts that can accentuate the degradation of stone materials; biological data, related to the appearance of vegetation or natural colonies that can alter surfaces; and finally, dimensional data, detectable through cameras to observe any movements, changes, color alterations, or structural anomalies.
To effectively collect this information, specific equipment was selected: a weather station with advanced climate sensors and air quality modules; two multispectral cameras designed to analyze surfaces and detect changes that are not visible to the naked eye, such as leaks, moisture, salts, or hidden deterioration; and a portable thermal imaging camera, useful for performing targeted checks on masonry, cladding, and sensitive parts of the villa. These devices are accompanied by all the necessary components—cables, antennas, converters, and power supply systems—and, above all, a fanless industrial PC that acts as a local data collection center. The physical layout of the instruments has been designed to minimize the impact on the site while ensuring optimal performance: the weather station is placed on a support above the canopy, the multispectral cameras are mounted on adjustable supports to monitor the thermal mosaic and the rock face respectively, while the thermal imaging camera is provided as a mobile instrument that can be used as needed. Particular attention was paid to ensuring that the weather station was correctly oriented towards the north, which is essential for accurately measuring wind direction. Inside the canopy are industrial PCs, converters, and antennas, protected by structures that guarantee their durability and efficiency over time.
Table of sensors selected for monitoring the Roman Villa in Realmonte (AG), with details of the data collected, the quantities required, and device references
System architecture
The system architecture completes the technological framework, ensuring that all devices can communicate with each other and with the central IoT platform. The fanless industrial PC, located under the canopy and protected inside a dedicated box, is the main node of the entire infrastructure: it collects data from the weather station via wireless communication or RS-232 serial connection, powers and manages the multispectral cameras via USB cables, and acts as a local Wi-Fi hotspot to automatically start image acquisition from the cameras every six hours. The thermal camera, on the other hand, remains a stand-alone device with rechargeable batteries, which can be used flexibly and independently of the central power supply. All the information collected is processed directly by the industrial PC and sent in real time to the remote IoT platform via the LTE/4G connection provided by a dedicated dongle with an external antenna, installed to ensure stability even in the presence of the metal canopy, which could obstruct the signal.
From an energy perspective, the entire infrastructure is powered by a 48 V line obtained from the electrical panel located at the entrance to the villa: this voltage, chosen to reduce potential drops along the route and to ensure safety for visitors and operators, is distributed along the walkway and then converted locally to 12 V to power the weather station and industrial PC.
Route of the 48 V DC electrical track from the house to the entrance of the Roman Villa in Realmonte to the monitoring area, laid along the walkway
All devices are mounted under the canopy without additional junction boxes, thus simplifying the system, reducing points of vulnerability, and facilitating maintenance. The set of connections, power supplies, and communication channels creates a solid network, designed to function even in difficult conditions and to ensure constant supervision of the archaeological site. The central platform receives data in real time, allowing for long-term analysis of the evolution of degradation phenomena, identification of any imminent risks, and planning of targeted interventions, ensuring more informed and effective protection of the Roman Villa of Realmonte.
Layout of sensors for monitoring the state of conservation of the mosaic in the thermal area of the Roman Villa in Realmonte (AG)
Diagram of the monitoring system for the Roman Villa in Realmonte, showing the devices, power supplies required, and communication protocols used