Open-source digital technologies for low-cost monitoring of historical constructions

This paper shows new possibilities of using novel, open-source, low-cost platforms for the structural health monitoring of heritage structures. The objective of the study is to present an assessment of increasingly available open-source digital modeling and fabrication technologies in order to identify the suitable counterparts of the typical components of a continuous static monitoring system for a historical construction. The results of the research include a simple case-study, which is presented with low-cost, open-source, calibrated components, as well as an assessment of different alternatives for deploying basic structural health monitoring arrangements. The results of the research show the great potential of these existing technologies that may help to promote a widespread and cost-efficient monitoring of the built cultural heritage. Such scenario may contribute to the onset of commonplace digital records of historical constructions in an open-source, versatile and reliable fashion.Peer ReviewedPostprint (author's final draft

design of a smart system for indoor climate control in historic underground built environment

Abstract The application of sensors-actuators networks in Building Heritage can lead to significant improvement in indoor climate control, with the aim to both reduce energy consumption, and improve conditions for occupants and hosted Heritage. This study proposes the preliminary design of a smart indoor climate control system, based on low-impact application criteria, which can be applied to visited underground built environment. The system is based on the balance of hygrothermal loads. Sensors and actuators requirements are defined, and control algorithm are based on the comparison between real-time monitored and "natural" temperature and hygrometric values (for stationary and transitory conditions)

Development of a new device for the measurement and modeling of an innovative risk index for cultural heritage application

The monitoring, as a function of time, of environmental parameters in cultural heritage is essential to preserve materials, to recognize the reasons of degradation and to evaluate their effects. The degrading effects of objects in cultural heritage field, can be classified in optical, morphological, physical-chemical/mechanical and alterations and depend by micro-climatic conditions. For this reason, in recent years, several solutions have been developed and commercialized for environmental monitoring, some compatible with general advice and others OEM (Original Equipment Manufacturing). However, the trend of application between compliant and non-ISO-compliant devices has not yet been sufficiently analyzed. In this first section, we show how in the last ten years researchers have shifted their attention to custom-made devices based on new generation sensors despite the expense of units ISO certified. The study based on a review of scientific articles has shown that: with the increase of low-cost and open-source technologies applied in the Environmental Impact Assessment (EIA) and in particular in the cultural heritage, led to a research advancement in the field, but, at the same time, increased non-homogeneity of the methods, impinging comparability of results. In recent years the trend is to use low-cost automatic wireless systems. This innovation, however, opens new scenarios and challenges on how to improve their stability, longevity, and sensitivity; reduce maintenance (battery replacement, including calibration or sensors); improve data analysis/management/display costs. In particular, it has highlighted the current difficulty of low-cost detectors to satisfy the robustness and reliability of regulatory and conventional stationary monitors at the expense of the periods and aesthetics. We have therefore paid particular attention to the sensitivity and reliability of the innovative solutions presented to overcome the traditional limitations, as well as to the real feasibility of solutions regarding sustainability, adaptability to the works of art or price. We also see the need for more communication between the scientific community and the decision-makers, who have only recently opened up to this paradigm. We highlighted the need to identify recurrent or innovative topics in the various documents concerning the approaches to preventive conservation, the preservation of damage and environmental management. After a review of state of the art regarding the different sampling device applied in cultural heritage and a survey of the parameters that involve a degradation effect on the materials, in this section, we focus our attention on a sensors-based prototype able to detect: (i) temperature and relative humidity; (ii) NO, NO2 and SO2; (iii) vibrations. In particular, this section describes the design and the validation of the Wireless Sensor Network (WSN) propose3, named WENDY, an acronym for Wireless Environmental moNitoring Device prototYpe. WENDY, built on a microcontroller of ATmega328P series, gathers signals from a sensor for temperature and relative humidity; a 9-axis MIMU; and three gas detection miniature boards (NO, NO2 and SO2). Complete the board a connector for memory card (SD) and an RTC. Additionally, a module based on the ZigBee standard could be used to transmit all data. In this section, precisely, we present the performances of the WSN node in detecting: structure tilt, vibrations and the daily cycle of humidity, temperature and gas deposition. The experimental setup used to evaluate the accuracy of MIMU system highlighted a relative error on shock acceleration measurement, in term of normalized root mean square error, lower than 0.1 % for the sinusoidal input and 0.51 % for cardinal sin input, with an average accuracy in the principal peak reconstruction of 1 % in the chosen frequency range (5 Hz to 50 Hz). The MIMU accuracy for tilt measurement, evaluated through the root mean square error was equal to 0.3° and a standard deviation always lower than 0.4° in the 0-90° tilt range. The gas detection and temperature/ humidity boards showed data comparable with the nearby certified ARPA system device. The aim of the applicative section is monitoring effects of different factors which affect the “Minerva Medica Temple,” an archeological site in Rome. In particular, we focus on: (i) the seasonal thermal variations on the structure; (ii) the contamination due to by local traffic regarding gaseous pollutant and (iii) the dynamic response of the structure to a tramway line located in Rome and called “Roma- Giardinetti.” The developed system allows for prioritization of intervention both for management and interventions planning, regarding restoration, consolidation, and conservation. Moreover, the software structure of the environmental monitoring device is presented and expounded in detail.4 Always in this section, an innovative procedure for the evaluation of the environmental hazard in cultural heritage is proposed. This risk assessment can be considered as a “relative risk assessment methodology.” In particular, it considers the impacts of microclimatic conditions on the monument, based on the international norms and the current scientific knowledge. For measurement campaigns with WENDY, the risk method proposed is applied to the results of two measurement campaigns carried out between 2017 and 2018 over two different periods (September-December and March-July), at “Minerva Medica Temple,” in Rome

An overview on nature-inspired optimization algorithms for Structural Health Monitoring of historical buildings

Structural Health Monitoring (SHM) of historical building is an emerging field of research aimed at the development of strategies for on-line assessment of structural condition and identification of damage in the earliest stage. Built heritage is weak against operational and environmental condition and preservation must guarantee minimum repair and non-intrusiveness. SHM provides a cost-effective management and maintenance allowing prevention and prioritization of the interventions. Recently, in computer science, mimicking nature to address complex problems is becoming more frequent. Nature-inspired approaches turn out to be extremely efficient in facing optimization, commonly used to analyze engineering processes in SHM, providing interesting advantages when compared with classic methods. This paper begins with an introduction to Natural Computing. Then, focusing on its applications to SHM, possible improvements in built heritage conservation are shown and discussed suggesting a general framework for safety assessment and damage identification of existing structures.This work was financed by FEDER funds through the Competitiveness Factors Operational Programme COMPETE and by national funds through FCT - Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007633info:eu-repo/semantics/publishedVersio

HBIM: Low-cost sensors and environmental data in heritage buildings - A guide for practitioners and professionals

This guide is intended to introduce the heritage conservation professional to the use of low cost sensors to capture environmental data in occupied heritage buildings, for the purposes of enhancing the heritage preservation practice with the capability for real-time monitoring and analysis of the buildings state.The first part of this document is an introduction to the applications of sensors and data capture in buildings, followed by a more detailed discussion of the particular variables to be captured and the technology available. The second part is a guide to choosing equipment, deployment, and using the captured data, with recommendations for best practice

Low-cost and distributed health monitoring system for critical buildings

In this paper we present a low-cost distributed embedded system for Structural Health Monitoring (SHM) that uses very cost-effective MEMS accelerometers, instead of more expensive piezoelectric analog transducers. The proposed platform provides online filtering and fusion of the collected data directly on-board. Data are transmitted after processing using a WiFi transceiver. Low-cost and synchronized devices permit to have more fine-grained measurements and a comprehensive assessment of the whole building, by evaluating their response to vibrations. The challenge addressed in this paper is to execute a quite computationally-demanding digital filtering on a low-cost microcontroller STM32, and to reduce the signal-to-noise ratio typical of MEMS devices with a spatial redundancy of the sensors. Our work poses the basis for low-cost methods for elaborating complex modal analysis of buildings and structures

Multivariate characterization of temperature fluctuations in a historical building using energy-efficient IoT wireless sensors

[EN] Adequate thermic conditions are required for the preventive conservation of artworks, but such optimum conditions cannot always be achieved in historical buildings such as ancient churches. In those cases, it is of interest to assess the potential risk of punctual changes in indoor environments that can be harmful to artworks. These conditions can be assessed by means of a microclimate monitoring system comprised of a set of energy¿efficient wireless sensors connected to the cloud using IoT techniques. This approach was followed at the baroque church of Saint Thomas and Saint Philip Neri in Valencia (Spain). A set of 26 wireless nodes was installed, which recorded values of temperature and relative humidity every hour for a period of 7 months. Small differences of temperature were obtained among sensors, so that an efficient methodology based on principal component analysis (PCA) was applied for the characterization of similarities and dissimilarities between sensors. Daily ranges of temperatures were studied as well as mean trajectories, differences between days of the week, and changes in the correlation structure of daily median values over time. Results provide a framework for an efficient characterization of temperatures in heritage buildings based on a network of wireless sensors. Such a framework is useful to assess the potential risk of temperature fluctuations on the preventive conservation of historical buildings and artworks.Funding This research was funded by the European Unions Horizon 2020 research and innovation program under grant agreement No. 814624.Zarzo Castelló, M.; Perles, A.; Mercado Romero, R.; García Diego, FJ. (2021). Multivariate characterization of temperature fluctuations in a historical building using energy-efficient IoT wireless sensors. Sensors. 21(23):1-32. https://doi.org/10.3390/s21237795S132212

Impact of Pyrotechnics over the Architectonic Heritage

[EN] The use of pyrotechnics near to the historical heritage such as walls, facades, church, or fortifications of a city is nowadays a topic of discussion. There is not a clear legislation about the use of pyrotechnics near to these buildings and how they can be affected by the expansive wave generated by the use of harquebusiers, fireworks, and cannons during the simulation of a battle. For this reason, this paper presents some practical tests that measure the vibroacoustic effect when these types of pyrotechnics are used near to the architectonical heritage. In order to collect these data, we have used several sound level meters and accelerometers placed on two different scenarios. The first one was placed near to the beach and the other one was placed in a building of a narrow alley. The tests were carried out during the festival of Moors and Christians of Villajoyosa (Spain) which is a famous festival. Along these tests, we reproduce the worse cases that may affect the building, using harquebusiers shots, fireworks, and cannons shots. Results show that the house placed near to the beach does not suffer important vibroacoustic impacts. However, the old building placed in the alley is very affected.Lloret, AT.; Sendra, S.; Lloret, J.; Cereceda, ML.; Alba Fernández, J. (2017). Impact of Pyrotechnics over the Architectonic Heritage. Journal of Sensors. 2017:1-11. doi:10.1155/2017/7214975S111201

Monitoring Ancient Buildings: Real Deployment of an IoT System Enhanced by UAVs and Virtual Reality

The historical buildings of a nation are the tangible signs of its history and culture. Their preservation deserves considerable attention, being of primary importance from a historical, cultural, and economic point of view. Having a scalable and reliable monitoring system plays an important role in the Structural Health Monitoring (SHM): therefore, this paper proposes an Internet Of Things (IoT) architecture for a remote monitoring system that is able to integrate, through the Virtual Reality (VR) paradigm, the environmental and mechanical data acquired by a wireless sensor network set on three ancient buildings with the images and context information acquired by an Unmanned Aerial Vehicle (UAV). Moreover, the information provided by the UAV allows to promptly inspect the critical structural damage, such as the patterns of cracks in the structural components of the building being monitored. Our approach opens new scenarios to support SHM activities, because an operator can interact with real-time data retrieved from a Wireless Sensor Network (WSN) by means of the VR environment