Role of Hellenic Range and Pasture Society in Technology Interaction and Policy Evolution

The Hellenic Range and Pasture Society (HRPS) was founded in 1992 and is a non-profit scientific association. It is composed of 74 members with a common interest in the study, management, and rational use of rangelands and related ecosystems (e.g. pasturelands). The objectives for which the corporation was established are: a) to develop an understanding of rangeland ecosystems and of the principles applicable to the management of rangeland resources (soil, plants, water, and animals), b) to assist all who work with rangelands and pasturelands to keep abreast of new findings and techniques in the science and art of rangeland and pasture management, c) to create a public appreciation of the economic and social benefits to be obtained from the rangeland environment, and d) to promote professional development of its members

An Automated Machine-Learning Approach for Road Pothole Detection Using Smartphone Sensor Data.

Road surface monitoring and maintenance are essential for driving comfort, transport safety and preserving infrastructure integrity. Traditional road condition monitoring is regularly conducted by specially designed instrumented vehicles, which requires time and money and is only able to cover a limited proportion of the road network. In light of the ubiquitous use of smartphones, this paper proposes an automatic pothole detection system utilizing the built-in vibration sensors and global positioning system receivers in smartphones. We collected road condition data in a city using dedicated vehicles and smartphones with a purpose-built mobile application designed for this study. A series of processing methods were applied to the collected data, and features from different frequency domains were extracted, along with various machine-learning classifiers. The results indicated that features from the time and frequency domains outperformed other features for identifying potholes. Among the classifiers tested, the Random Forest method exhibited the best classification performance for potholes, with a precision of 88.5% and recall of 75%. Finally, we validated the proposed method using datasets generated from different road types and examined its universality and robustness

Net-zero solutions and research priorities in the 2020s

Key messages • Technological, societal and nature-based solutions should work together to enable systemic change towards a regenerative society, and to deliver net-zero greenhouse gas (GHG) emissions. • Prioritise research into efficient, low-carbon and carbon-negative solutions for sectors that are difficult to decarbonise; i.e. energy storage, road transport, shipping, aviation and grid infrastructure. • Each solution should be assessed with respect to GHG emissions reductions, energy efficiency and societal implications to provide a basis for developing long-term policies, maximising positive impact of investment and research effort, and guiding industry investors in safe and responsible planning

Estimating the ride quality characteristics of vehicles with random decrement analysis of on-the-road vibration response data

ABSTRACT: This paper describes the application of a practical analytical technique based on the random decrement method to estimate the rigid sprung mass dynamic characteristics (frequency response function) of road vehicles using only vibration response data during constant-speed operation. A brief history and development of the random decrement technique is presented, along with a summary of work undertaken on optimal parameter selection to establish the random decrement signature. Two approaches to estimate the dynamic characteristics from the random decrement signature are described and evaluated. A custom, single-wheeled vehicle (physical quarter car) was commissioned to undertake a series of on-the-road experiments at various nominally constant operating speeds. The vehicle, also instrumented as an inertial profilometer, simultaneously measured the longitudinal pavement profile to establish the vehicle's actual dynamic characteristics during operation. The main outcome of the paper is that the random decrement technique can be used to provide accurate estimates of the sprung mass mode of the vehicle's dynamic characteristics for both linear and nonlinear suspension systems of an idealised vehicle

An adaptive impulse response technique for evaluating the performance of structural elements

It is well established that loss of structural integrity is reflected by variations in modal characteristics such as natural frequency. Generally, these characteristics are extracted using the system's frequency response function (FRF), obtained using the Fourier transform. However, the Fourier transform requires that a compromise be made between the spectral accuracy of the estimates and how frequently they can be obtained. This compromise significantly limits the potential of Fourier based techniques as continuous structural integrity assessment tools. The research presented herein uses the system's instantaneous impulse response function, captured using the coefficients of an adaptive finite impulse response (FIR) filter, to continuously monitor shifts in the system's natural frequency. This approach allows for the properties of systems to be evaluated at regular intervals without compromising spectral uncertainty. © 2011 Taylor & Francis Group, London

Estimation of road transport vehicle dynamic characteristics using random decrement analysis and on-the-road vibration data

This paper presents the application of a recently developed and validated approach to accurately estimate the sprung mass mode dynamic characteristics of road transport vehicles using only on-the-road vertical vibration response data during constant speed operation. A description of the developed analytical approach using the random decrement technique and the Hilbert transform is included. Three experimental case studies are presented, each using a different road transport vehicle travelling at various nominally constant operating speeds over different roads to demonstrate the ability of the on-the-road approach to practically estimate the sprung mass modal properties, namely natural frequency and damping. The estimated dynamic characteristics were compared with different experimental procedures currently in use, including response-only (transient), and excitation-response methods. The new method provides a simpler, cost effective, and practical approach to obtain reliable and realistic estimates of the sprung mass mode natural frequency and damping ratio

A practical approach to Fourier analysis for monitoring structural integrity

It is sometimes necessary to determine the manner in which materials deteriorate with respect to time; for instance when quantifying a material's ability to withstand sustained dynamic loads. In such cases, it is well established that loss of structural integrity is reflected by variations in modal characteristics such as natural frequency. The research presented herein uses the system's "instantaneous" frequency response function (FRF), captured using a modified short-time Fourier transform (STFT), to continuously monitor shifts in the system's natural frequency. This approach requires a compromise to be made between the accuracy of spectral estimates and how often they can be made. This paper uses the results from numerous physical and numerical experiments to address some practical limitations of Fourier analysis with respect to temporal resolution and the uncertainties associated with extracting variations in modal parameters. Results which allow the analyst to select suitable inputs for parameter extraction are also included. © 2011 Taylor & Francis Group, London

Numerical modelling of the ground-borne vibrations generated by truck-road interaction

Like railway-induced ground vibrations, ground-borne motions generated by the passing of heavy vehicles in urban areas are one of the fundamental problems in transport annoyance in the vicinity of buildings. In presence of local geometries like a speed bump or pavement defects, wheels interact with the road surface and cause dynamic motions in the vehicle that reacts with the road and generates high level vibrations that propagate in the soil through complex waves and impinge on the foundations of nearby structures. The scope of this study is twofold. The first part is dedicated to the prediction of vibration levels using a two-step approach. A multibody approach is used for the vehicle modelling, including the tyre/bump/road interaction. A finite element analysis is used for the next approach, calculating the ground wave propagation of a moving load, defined as the output of the first calculation. A decoupled simulation is possible due to the large stiffness of the road compared to the stiffness characteristics of the vehicle (tyre). A validation is performed using experimental data available in the literature. The second part focuses on a sensitivity analysis in order to identify the main parameters (bump geometry, speed,...) that affect the shape and level of peak particle velocity at various distances from the road. In light of the study, the prediction scheme offers an efficient way to design speed bumps and to understand the complex waves generated by a transient moving load propagating in an infinite medium

A multi-resolution time domain technique for monitoring fatigue progression in elements subjected to random loads

Materials and structures subjected to random loading can deteriorate in a complex fashion. A technique for monitoring the manner in which this decay occurs can be useful, not in the least, for comparative analysis. One method for monitoring structural deterioration is to continually track variations in the system's modal parameters. Modal parameters are often extracted using the system's frequency response function, obtained using the Fourier transform. However, for continual parameter extraction, the Fourier transform requires that a compromise be made between the spectral accuracy of the estimates and how frequently they can be obtained. This compromise significantly limits the potential of Fourier transform based techniques as continuous structural integrity assessment tools. The technique presented herein applies the Hilbert transform to the system's instantaneous impulse response function, captured using the coefficients of an adaptive finite-impulse-response filter, in order to continually monitor shifts in the system's natural frequency. This approach allows for the properties of systems to be evaluated at regular intervals without compromising spectral uncertainty. Numerous damage scenarios were performed (using both physical and numerical systems) in order to test the sensitivity of the technique as well as its ability to converge with changes in system characteristics. © Institution of Engineers Australia, 2011

Practical Considerations for Estimating Road Vehicle Frequency Response Functions from Response Data

This paper describes the application of a practical method to estimate the dynamic characteristics (frequency response function) of road vehicles using only on-the-road vertical vibration response data measured during nominally constant operating speeds. While several methods exist to estimate these dynamic characteristics, they are generally either inexact or prohibitively resource intensive. A review of two analytical approaches for estimating the frequency response function of road vehicles using only on-the-road vibration response data is presented. The first approach is based on the assumption that the road elevation profile takes the form of a specified spectral function. The second approach is based on the random decrement technique. A practical, step-by-step guide to undertaking on-the-road vehicle vibration measurements is included and provides numerous useful tips and considerations that should be taken into account. An investigation was also undertaken into the minimum record length (i.e. fraction of road length) required to accurately estimate the dynamic characteristics of road vehicles using a Monte Carlo simulation. From the study, it was found that a minimum road length of 10 – 15 km is sufficient to obtain a reasonably accurate estimate. Copyright © 2017 John Wiley & Sons, Ltd