30th International Conference on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2017)

Proceedings of COMADEM 201

Evaluation of Pavement Roughness and Vehicle Vibrations for Road Surface Profiling

The research explores aspects of road surface measurement and monitoring, targeting some of the main challenges in the field, including cost and portability of high-speed inertial profilers. These challenges are due to the complexities of modern profilers to integrate various sensors while using advanced algorithms and processes to analyse measured sensor data. Novel techniques were proposed to improve the accuracy of road surface longitudinal profiles using inertial profilers. The thesis presents a Half-Wavelength Peak Matching (HWPM) model, designed for inertial profilers that integrate a laser displacement sensor and an accelerometer to evaluate surface irregularities. The model provides an alternative approach to drift correction in accelerometers, which is a major challenge when evaluating displacement from acceleration. The theory relies on using data from the laser displacement sensor to estimate a correction offset for the derived displacement. The study also proposes an alternative technique to evaluating vibration velocity, which improves on computational factors when compared to commonly used methods. The aim is to explore a different dimension to road roughness evaluation, by investigating the effect of surface irregularities on vehicle vibration. The measured samples show that the drift in the displacement calculated from the accelerometer increased as the vehicle speed at which the road measurement was taken increased. As such, the significance of the HWPM model is more apparent at higher vehicle speeds, where the results obtained show noticeable improvements to current techniques. All results and analysis carried out to validate the model are based on real-time data obtained from an inertial profiler that was designed and developed for the research. The profiler, which is designed for portability, scalability and accuracy, provides a Power Over Ethernet (POE) enabled solution to cope with the demand for high data transmission rates.

Roadmap on signal processing for next generation measurement systems

Signal processing is a fundamental component of almost any sensor-enabled system, with a wide range of applications across different scientific disciplines. Time series data, images, and video sequences comprise representative forms of signals that can be enhanced and analysed for information extraction and quantification. The recent advances in artificial intelligence and machine learning are shifting the research attention towards intelligent, data-driven, signal processing. This roadmap presents a critical overview of the state-of-the-art methods and applications aiming to highlight future challenges and research opportunities towards next generation measurement systems. It covers a broad spectrum of topics ranging from basic to industrial research, organized in concise thematic sections that reflect the trends and the impacts of current and future developments per research field. Furthermore, it offers guidance to researchers and funding agencies in identifying new prospects.AerodynamicsMicrowave Sensing, Signals & System

Novel Approaches for Structural Health Monitoring

The thirty-plus years of progress in the field of structural health monitoring (SHM) have left a paramount impact on our everyday lives. Be it for the monitoring of fixed- and rotary-wing aircrafts, for the preservation of the cultural and architectural heritage, or for the predictive maintenance of long-span bridges or wind farms, SHM has shaped the framework of many engineering fields. Given the current state of quantitative and principled methodologies, it is nowadays possible to rapidly and consistently evaluate the structural safety of industrial machines, modern concrete buildings, historical masonry complexes, etc., to test their capability and to serve their intended purpose. However, old unsolved problematics as well as new challenges exist. Furthermore, unprecedented conditions, such as stricter safety requirements and ageing civil infrastructure, pose new challenges for confrontation. Therefore, this Special Issue gathers the main contributions of academics and practitioners in civil, aerospace, and mechanical engineering to provide a common ground for structural health monitoring in dealing with old and new aspects of this ever-growing research field

Machine Learning in Tribology

Tribology has been and continues to be one of the most relevant fields, being present in almost all aspects of our lives. The understanding of tribology provides us with solutions for future technical challenges. At the root of all advances made so far are multitudes of precise experiments and an increasing number of advanced computer simulations across different scales and multiple physical disciplines. Based upon this sound and data-rich foundation, advanced data handling, analysis and learning methods can be developed and employed to expand existing knowledge. Therefore, modern machine learning (ML) or artificial intelligence (AI) methods provide opportunities to explore the complex processes in tribological systems and to classify or quantify their behavior in an efficient or even real-time way. Thus, their potential also goes beyond purely academic aspects into actual industrial applications. To help pave the way, this article collection aimed to present the latest research on ML or AI approaches for solving tribology-related issues generating true added value beyond just buzzwords. In this sense, this Special Issue can support researchers in identifying initial selections and best practice solutions for ML in tribology

Some NASA contributions to human factors engineering: A survey

This survey presents the NASA contributions to the state of the art of human factors engineering, and indicates that these contributions have a variety of applications to nonaerospace activities. Emphasis is placed on contributions relative to man's sensory, motor, decisionmaking, and cognitive behavior and on applications that advance human factors technology

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 192

This bibliography lists 247 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1979

Development of a new approach for predicting tram track degradation based on passenger ride/comfort data

These days tram as a type of the public transport system has become popular because of its attractive features such as road usage efficiency, low emission of pollutants, reduction in traffic congestion and efficiency in capital costs and maintenance expenses compared to private cars. For the case study, the Melbourne tram network, which is the longest tram network in the world, has been targeted. Melbourne tram system consists of 493 trams, 24 routes, and 1,763 tram stops. According to the operator of the Melbourne tram network, the total number of patronage in 2017-2018 was 206.3 million. In parallel with the annual increase in tram demand and patronage, tram infrastructure systems need to bear more stresses and traffic pressure. Track degradation is a common problem in the area of tram track infrastructure. One of the main aspects of track degradation is the presence of irregularity in track geometric parameters. In order to deal with degradation problems, tram track infrastructure maintenance management systems have been developed for design and implementation of maintenance works and renewal activities. Track degradation prediction models are the core and the main part of these management systems. Without accurately predicting the future condition of tram tracks, designing and providing preventive maintenance strategies are not feasible. In this research, the collected data which cover six sequential years (2010 to 2015) have been analysed and influencing parameters in tram track degradation have been identified. Gauge and twist were identified as the influencing track geometry parameters in the tram track degradation. Besides that, track surface and rail support as structural parameters were identified as significant parameters in prediction of future track geometry parameters and consequently tram track degradation. In order to develop tram track degradation prediction models and according to the successful experience of the previous studies, three types of prediction models including Artificial Neural Network (ANN), Support Vector Machine (SVM) and Random Forest Regression (RFR) models have been created. According to the results, RFR models provide better predictions in terms of the performance indicators including the coefficient of determination and Root Mean Squared Error (RMSE) compared to the ANN and SVM models. In this research, based on the Melbourne tram track dataset, a new track degradation index has been proposed. Track degradation indices can be used as an indicator of rail condition concerning the risk of damage or failure over a period of time. The index can be applied in establishing a sustainable tram track maintenance management system. The new index composed of two main parts including the mean value of the geometry deviation and the average differential geometry deviation. The proposed index has been compared with three major track geometry degradation indices. For this purpose, the predictability performance of the indices has been considered. In this regard, the Pearson correlation analysis was applied to previous and current values of the indices. According to the results, the correlation coefficient of the proposed index was higher than the other indices. The finding of the evaluation presented that the proposed index can be used as an effective measure for the assessment of the geometric condition of tram tracks. In this research, a new approach has been proposed to predict the tram track degradation were which is cost-effective and can be carried out repeatedly without imposing delay to tram services. Conventional approaches are mainly based on the previous track geometry parameters which have been discussed in this research. In the new approach, passenger ride comfort data or acceleration data has been used to predict the future condition of track geometry parameters which has been represented by the tram track degradation index. For developing the degradation prediction models, the previous models which have been used to predict the degradation based on the track geometry parameters were applied. The future degradation index has been targeted as the target variable and acceleration parameter besides the structural parameters have been used as the explanatory variables. According to the results of the evaluation, the RFR model can predict the future degradation index with approximately 10 percent higher R2 and 9 percent lower prediction error compared to other developed models. In this research two methods for predicting the future tram track degradation index, first was the method based on the previous track geometry parameters and the second was the method based on the acceleration data, have been presented. According to the results of the degradation index prediction based on the previous track geometry parameters, RMSE was 0.35 and R2 value was 0.95. On the other hand, for the prediction based on the acceleration data, RMSE was 1.04 and R2 value was 0.74. The comparison of these methods shows that although the prediction error has been increased and R2 value has been decreased in the latest method, the values of the performance indicators are still in acceptable ranges. These results imply that the prediction of tram track degradation based on the acceleration data can be considered as a reliable method along with conventional tram track degradation prediction method for maintaining tram tracks. The proposed method can provide more predictions of potential future faults by reducing inspection costs and inspection intervals

Fourth Annual Workshop on Space Operations Applications and Research (SOAR 90)

The papers from the symposium are presented. Emphasis is placed on human factors engineering and space environment interactions. The technical areas covered in the human factors section include: satellite monitoring and control, man-computer interfaces, expert systems, AI/robotics interfaces, crew system dynamics, and display devices. The space environment interactions section presents the following topics: space plasma interaction, spacecraft contamination, space debris, and atomic oxygen interaction with materials. Some of the above topics are discussed in relation to the space station and space shuttle