Search results for "Reliability and Quality"
showing 10 items of 386 documents
Estimating the occurrence of traffic accidents near school locations: A case study from Valencia (Spain) including several approaches
2019
Traffic safety around school locations is a topic of particular interest given the large number of vulnerable users, such as pedestrians or cyclists, that commute to them at certain times of the day. A dataset of traffic accidents recorded in Valencia (Spain) during 2014 and 2015 is analyzed in order to estimate the effects that school locations produce on traffic risk within their surroundings. The four typologies of school in this city according to the academic levels they offer (All-level, Preschool, Primary, Secondary) are distinguished and taken into consideration for the analysis. Two time windows comprising the starting time in the morning and the evening time once day school has end…
Mixed Harmonic Elimination Control for a Single-Phase 9 Level Grid-Connected Inverter
2018
The power quality requirements are increasingly stringent, due to the continuous growth of devices connected to the grid that introduce harmonics. These devices include DC to AC energy conversion systems, i.e. grid connected inverters. The design, control and operation of these systems must take into account the rules of interconnection to the electricity grid. To improve the quality of the output waveform of the grid-connected inverter, Multilevel Converters (MC) with selective harmonic elimination modulation technique can be used. This paper presents a single-phase nine level grid-connected inverter with DC/DC input stages. The obtained switching angles for THD minimization are independen…
The International Measurement Evaluation Programme (IMEP) IMEP-6: "Trace elements in water"
1998
The sixth round of the International Measurement Evaluation Programme (IMEP) is presented. The programme offers reference values, established by primary methods of measurement, against which participating laboratories can evaluate their performance. The degree of comparability is thus established against the most objective references available at present. In IMEP-6, reference values for total concentrations of 14 trace elements in a synthetic and a natural water were established mainly by isotope dilution mass spectrometry (IDMS). For the majority of the measurands, results traceable to the international system of units (SI) and having expanded uncertainties, U (k=2), of 2% could be establi…
Acceptance of truck platooning by professional drivers on German highways. A mixed methods approach.
2020
Abstract Truck platoon driving is a current branch of automated driving, which has the potential to radically change the work routine of professional drivers. In a platoon system, one truck (semi-)automatically follows a lead truck with a reduced distance, which produces significant savings in fuel and enables better traffic flow. In a current application of truck platoon driving, the following vehicle operates at level-2 automation. Thus, the driver of the following truck merely has to supervise the semi-automated system, which takes over steering and speed control when engaged. Level-2 truck platoon driving had not been tested with professional drivers in real traffic before. We hypothesi…
Are long-haul truck drivers unusually alert? A comparison with long-haul airline pilots.
2020
Abstract Background Recent studies suggest heavy vehicle drivers self-estimate their sleepiness unexpectedly low during night duties. The present study compared sleepiness ratings of long-haul truck drivers with those of long-haul airline pilots during night and non-night duties. In addition, the correspondence between self-rated manifest and predicted latent sleepiness was examined in the two groups. Methods Twenty-two drivers and 33 pilots participated. Their working hours, sleep, on-duty sleepiness, and use of sleepiness countermeasures were measured in naturalistic conditions. Predictions of latent sleepiness were based on the measurements of working hours and sleep using the Sleep/Wake…
Power production forecast for distributed wind energy systems using support vector regression
2022
Due to the inherent intermittency in wind power production, reliable short-term wind power production forecasting has become essential for the efficient grid and market integration of wind energy. The current wind power production forecasting schemes are predominantly developed for wind farms. With the rapid growth in the microgrid sector and the increasing number of wind turbines integrated with these local grids, power production forecasting schemes are becoming essential for distributed wind energy systems as well. This paper proposes a power production forecasting scheme developed explicitly for distributed wind energy projects. The proposed system integrates two submodels based on supp…
Condition classification of fibre ropes during cyclic bend over sheave testing using machine learning
2022
Fibre ropes have been shown to be a viable alternative to steel wire rope for offshore lifting operations. Visual inspection remains a common method of fibre rope condition monitoring and has the potential to be further automated by machine learning. This would provide a valuable aid to current inspection frameworks to make more accurate decisions on recertification or retirement of fibre ropes in operational use. Three different machine learning algorithms: decision tree, random forest and support vector machine are compared to classical statistical approaches such as logistic regression, k-nearest neighbours and Naïve-Bayes for condition classification for fibre ropes under cyclic-bend-ov…
Commentaries on our new ways of perceiving disasters
2010
PurposeThe purpose of this paper is to help readers gain more understanding of the new phenomena of terror, risk, and threat perception.Design/methodology/approachVarious authors are reviewed: Castel, Beck, Baral, Kellner, Sabada, Korstanje, and in particular, Baudrillard.FindingsSeveral matches are found among the reviewed authors which comprise, for example: late modernity (from 1970 to date) witnesses an increase of fears, panic, and risk assessments in social imaginary; these concerns are part of a process that opens the future to the contingency. That way, the decision‐making process in human beings sheds light on certain aspects of life such as health, body‐care planning but this has …
Perceived safety and attributed value as predictors of the intention to use autonomous vehicles: A national study with Spanish drivers
2019
Abstract Sooner than later, the growing development of Autonomous Vehicles (AVs) will represent not only an imminent transformation of transportation dynamics, but also further advantages for their users, including many improvements in road crash prevention, efficiency and sustainability. However, different concerns and constraints may affect the intention of adopting this technology among its potential customers, especially for what concerns those constraints related to safety, viability and stability. The objective of this study was to examine the influence of perceived safety and value attributed to the AV in the drivers’ intention to use it, considering the drivers’ demographic factors,…
Qualitative models of equipment units and their use in automatic HAZOP analysis
2000
Abstract The use of qualitative models in a support system for HAZOP analyses, in connection with an algorithm for finding the causes and the consequences of variable deviations, is described. The models use several representation structures among which mini-trees constitute the most important from the logical-functional point of view. The models are conceived both for continuous and batch plants. For the latter procedures, regulating the use of equipment units are also modelled using similar structures while equipment units are considered in various phases of their functioning. A brief description of the prototype support system, in which the models are implemented, is also given.