Data Mining Practical Machine Learning Tools and Techniques

The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Climate change 2014 - Mitigation of climate change

The book aims to provide a broad overview of various topics of the Internet of Things (IoT) from the research and development priorities to enabling technologies, architecture, security, privacy, interoperability and industrial applications. It is intended to be a standalone book in a series that covers the Internet of Things activities of the IERC ? Internet of Things European Research Cluster from technology to international cooperation and the global "state of play". The book builds on the ideas put forward by the European research Cluster on the Internet of Things Strategic Research Agenda and presents global views and state of the art results on the challenges facing the research, development and deployment of IoT at the global level.

Internet of Things: Converging Technologies for Smart Environments and Integrated Ecosystems

Renewable energy sources have gained much attention due to the recent energy crisis and the urge to get clean energy. Among the main options being studied, wind energy is a strong contender because of its reliability due to the maturity of the technology, good infrastructure and relative cost competitiveness. In order to harvest wind energy more efficiently, the size of wind turbines has become physically larger, making maintenance and repair works difficult. In order to improve safety considerations, to minimize down time, to lower the frequency of sudden breakdowns and associated huge maintenance and logistic costs and to provide reliable power generation, the wind turbines must be monitored from time to time to ensure that they are in good condition. Among all the monitoring systems, the structural health monitoring (SHM) system is of primary importance because it is the structure that provides the integrity of the system. SHM systems and the related non-destructive test and evaluation methods are discussed in this review. As many of the methods function on local damage, the types of damage that occur commonly in relation to wind turbines, as well as the damage hot spots, are also included in this review.

https://iopscience.iop.org/article/10.1088/0957-0233/19/12/122001/pdf

Structural health monitoring for a wind turbine system: a review of damage detection methods

The author details the reactions of various concretes on steel reinforcement. Although portland cements, slag cements and high alumina cements are all hydraulic binders, each possess special properties which are examined. The discussion of causes and methods of preventing the corrosion of steel reinforcement covers such aspects as galvanised steel reinforcement, effects of concrete composition, corrosion of steel reinforcments in concrete and prestressed reinforcement. It is concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride; the presence of nitrates; the composition of the concrete; the degree of carbonation of the concrete; concrete compaction and, chlorides and sulphates should be used as far as possible when steel is embedded. (TRRL)

Corrosion of steel by concrete

This paper deals with the development of a measurement procedure to characterize anomalies, i.e. voids and defects, in four composite material (CM) samples. For this aim, four CM samples, each of them characterized by specific manufacturing techniques, have been analyzed. The first one (CM1) has Teflon defects, the second one (CM2) has undergone a low-degree manufacturing process and thus judged too porous at quality control, the third one (CM3) has passed the interlaminar shear strength (ILSS) test and so is expected to have a low-level of anomalies, unlike the fourth one (CM4), which has failed at ILSS test. An industrial X-ray computed tomography (CT) has been used to scan the CM samples and a specific image processing technique has been developed to measure the number and dimension of anomalies within them. The calculated amount of anomalies seems to be within the acceptable range identified in literature, always below 5%, showing the goodness of manufacturing process, and furthermore a threshold level of 0.09 mm has been statistically calculated to discriminate between voids and the other kinds of defects.

Characterization of porosity and defects on composite materials using X-ray computed tomography and image processing

This paper shows the results of an experimental campaign conducted to quantify the measurement uncertainty of heart rate variability (HRV), measured through a commercial smartwatch, while participants were performing office activities. The selected activities (sitting, moving the mouse, writing a text on the laptop, handwriting, walking, walking upstairs/downstairs) are subjected to motion artifacts (MA) that can negatively impact the HRV signal. Measurement uncertainty for each activity has been computed comparing the HRV acquired by the smartwatch with a reference sensor, i.e. multi-parametric chest belt BioHarness 3.0. Activities like resting and moving the mouse exhibit an uncertainty of ±60 ms and ± 90 ms, while activities such as handwriting, walking and walking upstairs/downstairs increase the measurement uncertainty from ±215 ms up to ±530 ms. These results are the preliminary step of a major study developed to measure the well-being of occupants using also HRV signals. In this context, accelerometer data, collected by the smartwatch, could possibly classify the activity performed by the workers through artificial intelligence (AI) algorithms; then, the HRV measurement uncertainty associated with the recognized activity could be used as a support for the discrimination of specific corrupted HRV segments, for minimizing the uncertainty in the HRV signal caused by MA.

Uncertainty of heart rate variability measured through a wearable device during office activities

Innovative denoising techniques based on Stationary Wavelet Transform (SWT) have started being applied to Pulsed Thermography (PT) sequences, showing marked potentialities in improving defect detection. In this contribution, a SWT-based denoising procedure is performed on high and low resolution PT sequences. Samples under test are two composite panels with known defects. The denoising procedure undergoes an optimization step. An innovative criterion for selecting the optimal decomposition level in multi-scale SWT-based denoising is proposed. The approach is based on a comparison, in the wavelet domain, of the information content in the thermal image with noise propagated. The optimal wavelet basis is selected according to two performance indexes, respectively based on the probability distribution of the information content of the denoised frame, and on the Energy-to-Shannon Entropy ratio. After the optimization step, denoising is applied on the whole thermal sequence. The approximation coefficients at the optimal level are moved to the frequency domain, then low-pass filtered. Linear Minimum Mean Square Error (LMMSE) is applied to detail coefficients at the optimal level. Finally, Pulsed Phase Thermography (PPT) is performed. The performance of the optimized denoising method in improving the defect detection capability respect to the non-denoised case is quantified using the Contrast Noise Ratio (CNR) criterion.

/pdf/stationary-wavelet-transform-for-denoising-pulsed-24k94ps5cq.pdf

Stationary Wavelet Transform for denoising Pulsed Thermography data: optimization of wavelet parameters for enhancing defects detection

In this paper it has been described part of the research devoted to the development of a complete non-intrusive experimental modal analysis procedure based on laser techniques both for excitation and for measurement. In particular, the attention has been focused to establish a mechanical equivalent system of forces and moments. An analytical model of the energy exchange between the light pulse and the target surface is proposed together with a finite element model of thermal and mechanical behaviour of the structure under excitation. Both the models (analytical and numerical) have been experimentally validated by measuring the thermal and the vibration responses induced by the laser pulses using an high-speed infrared camera and a scanning laser Doppler vibrometer.

Laser pulses in modal analysis : An experimental and numerical investigation

Due to the importance of torsional vibrations in mechanical rotating structures, increasing interest is nowaday devoted to the development of experimental techniques for torsional modal analysis. The rotational laser Doppler vibrometer seems to offer large potentials in this field, as it allows the analysis of torsional vibrations also under operational conditions with simple and non-contacting set-up.

Gian Marco Revel

Papers

Characterization of porosity and defects on composite materials using X-ray computed tomography and image processing

Uncertainty of heart rate variability measured through a wearable device during office activities

Stationary Wavelet Transform for denoising Pulsed Thermography data: optimization of wavelet parameters for enhancing defects detection

Laser pulses in modal analysis : An experimental and numerical investigation

Torsional vibrations: a laser vibrometry approach