Modern monitoring techniques contribute to accurately describing the structural health conditions of historical buildings and to optimising the plan of maintenance as well as the restoring intervention. Particularly, dynamic testing gives knowledge about global structural behaviour and can be used to calibrate numerical models and to predict the response to dynamic and earthquake loading. In some circumstances, vibration-based monitoring can also help in evaluating safety conditions. The present paper proposes a discussion about the methodological multidisciplinary approach to modal testing when applied to architectural heritage buildings and structures, along with the description of selected case studies. These examples were chosen to cover the various issues connected to test design and interpretation. Downloaded by [Selcuk Universitesi] at 18:21 05 February 2015 ACCEPTED MANUSCRIPT ACCEPTED MANUSCRIPT 2

Exploiting fine-grained semantic features on point cloud data is still challenging because of its irregular and sparse structure in a non-Euclidean space. In order to represent the local feature for each central point that is helpful towards better contextual learning, a max pooling operation is often used to highlight the most important feature in the local region. However, all other geometric local correlations between each central point and corresponding neighbourhood are ignored during the max pooling operation. To this end, the attention mechanism is promising in capturing node representation on graph-based data by attending over all the neighbouring nodes. In this paper, we propose a novel neural network for point cloud analysis, GAPointNet, which is able to learn local geometric representations by embedding graph attention mechanism within stacked Multi-Layer-Perceptron (MLP) layers. Specifically, we highlight different attention weights on the neighbourhood of each center point to efficiently exploit local features. We also combine attention features with local signature features generated by our attention pooling to fully extract local geometric structures and enhance the network robustness. The proposed GAPointNet architecture is tested on various benchmark datasets (i.e. ModelNet40, ShapeNet part, S3DIS, KITTI) and achieves state-of-the-art performance in both the shape classification and segmentation tasks.

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Optical measurements from high-speed, high-definition video recordings can be used to define the full-field dynamics of a structure. By comparing the dynamic responses resulting from both damaged and undamaged elements, Structural Health Monitoring (SHM) can be carried out, similarly as with mounted transducers. Unlike the physical sensors, which provide point-wise measurements and a limited number of output channels, high-quality video recording allows very spatially dense information. Moreover, video acquisition is a non-contact technique. This guarantees that any anomaly in the dynamic behaviour can be more easily correlated to damage and not to added mass or stiffness due to the installed sensors. However, in real-life scenarios, the vibrations due to environmental input are often so small that they are indistinguishable from measurement noise if conventional image-based techniques are applied. In order to improve the signal-to-noise ratio (SNR) in lowamplitude measurements, Phase-Based Motion Magnification (PBMM) has been recently proposed. This study intends to show that model-based SHM can be performed on modal data and time histories processed with PBMM, whereas unamplified vibrations would be too small for being successfully exploited. All the experiments were performed on a multidamaged box beam with different damage sizes and angles.

Sensitivity-based approaches to model updating have become widely used because of their capability to calibrate the model by taking into account the influence of updating parameters associated to different structural elements. Global sensitivity analysis (SA) allows model updating to be carried out even in the case of elevated uncertainty about the material characteristics. Architectural heritage structures deserve specific attention on account of their intrinsic geometrical complexity and heterogeneity. In this article, the concept of global SA is applied for the first time to complex monumental structures, and a comparative view is offered on more classical local sensitivity approaches. Different finite element (FE) calibration techniques—via global and local SA—were applied to the intriguing case of the church of S. Maria del Suffragio in L'Aquila (Italy), severely damaged by the 2009 earthquake. The FE updating was based on experimental data acquired by a dynamic monitoring system. Finally, calibration strategies were assessed through time history analyses by comparing the responses to the recorded seismic event