Historical Buildings Dampness Analysis Using Electrical Tomography and Machine Learning Algorithms (original) (raw)
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Energies
This paper presents the results of research on the use of machine learning algorithms and electrical tomography in detecting humidity inside the walls of old buildings and structures. The object of research was a historical building in Wrocław, Poland, built in the first decade of the 19th century. Using the prototype of an electric tomograph of our own design, a number of voltage measurements were made on selected parts of the building. Many algorithmic methods have been preliminarily analyzed. Ultimately, the three models based on machine learning were selected: linear regression with SVM (support vector machine) learner, linear regression with least squares learner, and a multilayer perceptron neural network. The classical Gauss–Newton model was also used in the comparison. Both the experiments based on real measurements and simulation data showed a higher efficiency of machine learning methods than the Gauss–Newton method. The tomographic methods surpassed the point methods in m...
The article presents the results of research on a new method of spatial analysis of walls and buildings moisture. Due to the fact that destructive methods are not suitable for historical buildings of great architectural significance, a non-destructive method based on electrical tomography has been adopted. A hybrid tomograph with special sensors was developed for the measurements. This device enables the acquisition of data, which are then reconstructed by appropriately developed methods enabling spatial analysis of wet buildings. Special electrodes that ensure good contact with the surface of porous building materials such as bricks and cement were introduced. During the research, a group of algorithms enabling supervised machine learning was analyzed. They have been used in the process of converting input electrical values into conductance depicted by the output image pixels. The conductance values of individual pixels of the output vector made it possible to obtain images of the ...
New electrical tomographic method to determine dampness in historical buildings
Archives of Electrical Engineering, 2016
This paper presents a new, nondestructive method of testing brick wall dampness in wall structures. The setup was used to determine the moisture in a specially built laboratory model. Topological methods and the gradient technique are used to optimize the approach. A forward model of a wall was constructed to solve the inverse problem resulting in moisture buildup inside the wall.
Energies
This paper refers to an original concept of tomographic measurement of brick wall humidity using an algorithm based on long short-term memory (LSTM) neural networks. The measurement vector was treated as a data sequence with a single time step in the presented study. This approach enabled the use of an algorithm utilising a recurrent deep neural network of the LSTM type as a system for converting the measurement vector into output images. A prototype electrical impedance tomograph was used in the research. The LSTM network, which is often employed for time series classification, was used to tackle the inverse problem. The task of the LSTM network was to convert 448 voltage measurements into spatial images of a selected section of a historical building’s brick wall. The 3D tomographic image mesh consisted of 11,297 finite elements. A novelty is using the measurement vector as a single time step sequence consisting of 448 features (channels). Through the appropriate selection of netwo...
Detect Dampness in Building Walls by Solving the Inverse Problem in Electrical Impedance Tomography
2019
The paper presents a measurement system based on electrical tomography. It will be an innovative solution for an evaluation study of the level of dampness of the walls and the condition of the building. Both in terms of the measuring method as the reconstruction algorithm. The application of modern tomographic techniques in conjunction with topological algorithms will allow to perform a non-invasive and very accurate spatial assessment of the dampness level. The authors of this paper propose a new kind of connection with the use of imaging techniques hybrid solution with surface electrodes.
Nondestructive Method to Determine Moisture Area in Historical Building
Informatics Control Measurement in Economy and Environment Protection, 2017
This paper presents a nondestructive method of brick wall dampness testing in real building structures. The proposed algorithm was used to determine the moisture of test brick walls on the specially models. The finite element method has been used to solve the forward problem. The algorithm is initialized by using one step methods and topological sensitivity analysis. There was constructed the forward model and solved the inverse for visualization of moisture inside objects.
Optimal thermographic procedures for moisture analysis in building materials
Diagnostic Imaging Technologies and Industrial Applications, 1999
The presence of moisture in building materials causes damage second only to structural one. NDT are successfully applied to map moisture distribution, to localise the source of water and to determine microclimatic conditions. IR Thermography has the advantage of non-destructive testing while it allows to investigate large surfaces. The measures can be repeated in time to monitor the phenomenon of raising water. Nevertheless the investigation of moisture in walls is one of the less reliable application of Thermography IR applied to cultural heritage preservation. The temperature of the damp areas can be colder then dry ones, because of surface evaporation, or can be warmer, because of the higher thermal inertia of water content versus building materials. The apparent discrepancies between the two results are due to the different microclimatic conditions of the scanning. Aim of the paper is to describe optimal procedures to obtain reliable maps of moisture in building materials, at different environmental and microclimatic conditions. Another goal is the description of the related energetic phenomena, which cause temperature discontinuities, and that are detected by thermography. Active and passive procedures are presented and compared. Case studies show some examples of procedures application.
Determining Location of Moisture Area of the Wall by 3D Electrical Impedance Tomography
Capillarity ascending wall dampness is a serious problem in older buildings with no or insufficient waterproofing layers. It is dangerous for technical conditions of the walls and also for people's health. There are many different dehumidification systems. Monitoring the wall humidity during the dehumidification process is very important and it could be done using electrical methods, because conductivity is changing with the humidity of the wall and its salinity. Electrical Impedance Tomography (EIT) technology may be used to determine conductivity distribution in the wall. The method of interface location between dry and dump region of the wall by EIT is presented in this paper. The multi region Boundary Element Method was used to solve the forward problem of EIT in such a case.