527 research outputs found
Quantile forecast discrimination ability and value
While probabilistic forecast verification for categorical forecasts is well
established, some of the existing concepts and methods have not found their
equivalent for the case of continuous variables. New tools dedicated to the
assessment of forecast discrimination ability and forecast value are introduced
here, based on quantile forecasts being the base product for the continuous
case (hence in a nonparametric framework). The relative user characteristic
(RUC) curve and the quantile value plot allow analysing the performance of a
forecast for a specific user in a decision-making framework. The RUC curve is
designed as a user-based discrimination tool and the quantile value plot
translates forecast discrimination ability in terms of economic value. The
relationship between the overall value of a quantile forecast and the
respective quantile skill score is also discussed. The application of these new
verification approaches and tools is illustrated based on synthetic datasets,
as well as for the case of global radiation forecasts from the high resolution
ensemble COSMO-DE-EPS of the German Weather Service
Indirect Electrografting of Aryl Iodides
International audienceThe electrografting of 4-iodonitrobenzene that is not possible directly is demonstrated whilst that of 5-iodo-2-amino-pyridine, 4-iodoaniline and iodobenzene is performed with a decrease of overpotential > 2 V. The electrografting of aryl iodides is achieved through a iodine abstraction reaction: in the presence of a sterically hindered diazonium salt (2,6-dimethylbenzenediazonium), the aryl iodide is grafted to gold at the much less negative reduction potential of the diazonium salt
Non-Destructive Testing Robots (NDTBOTS) for In-service Storage Tank Inspection
Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection takes many months and is very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to perform non-destructive testing. The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot (NDTBOT) which is designed to be intrinsically safe for zone zero operation. The robot “hops” across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water
Development of a novel crawler based robot for mooring chain climbing
Mooring systems experience high tidal waves, storms and harsh environmental conditions. Therefore, ensuring the integrity of mooring chain is important. The aim of the work reported in this paper is to develop a robotic system that performs in-service non-destructive testing of mooring chains. The inspection system is an autonomous device that operates in air as well as underwater. The permanent magnet adhesion crawler robot developed can climb mooring chains at a speed of 42cm/minute with a pay load of 50N. FEA study of the magnetic adhesion module, structural analysis, prototyping and testing of the robot is presented in this paper
Tracked-wheel crawler robot for vertically aligned mooring chain climbing design:simulation and validation of a climbing robot for mooring chain
Only a few attempts have been made to investigate the possibilities of developing chain climbing robot due to the complexity of the structure and physical nature of chain links. Mooring chains are subjected to large tidal waves, harsh environmental conditions and storms on a daily basis. Therefore, periodic inspection of the integrity of chain links is important. Work reported in this paper investigates the possibilities of mooring chain climbing by using tracked wheel locomotion. The permanent magnet adhesion, tracked wheel crawler robot developed for this purpose can climb on mooring chains both in air and underwater with a variable speed according to the inspection requirements (maximum speed of 42cm/minute). It is able to handle an external downward force of 50N during the climbing motion. Numerical modelling based analysis of a magnet adhesion module and the strength of the robot structure is validated with prototyping and testing of the concept
Adaptable legged-magnetic adhesion tracked wheel robotic platform for misaligned mooring chain climbing and inspection
London South Bank Innovation Centre (LSBIC); the National Structural Integrity Research Centre (NSIRC); TWI (NDT department), Cambridge
A reduced-reference perceptual image and video quality metric based on edge preservation
In image and video compression and transmission, it is important to rely on an objective image/video quality metric which accurately represents the subjective quality of processed images and video sequences. In some scenarios, it is also important to evaluate the quality of the received video sequence with minimal reference to the transmitted one. For instance, for quality improvement of video transmission through closed-loop optimisation, the video quality measure can be evaluated at the receiver and provided as feedback information to the system controller. The original image/video sequence-prior to compression and transmission-is not usually available at the receiver side, and it is important to rely at the receiver side on an objective video quality metric that does not need reference or needs minimal reference to the original video sequence. The observation that the human eye is very sensitive to edge and contour information of an image underpins the proposal of our reduced reference (RR) quality metric, which compares edge information between the distorted and the original image. Results highlight that the metric correlates well with subjective observations, also in comparison with commonly used full-reference metrics and with a state-of-the-art RR metric. © 2012 Martini et al
Fair Quality of Experience (QoE) Measurements Related with Networking Technologies
[Invited Talk] Eighth International Conference on Wired/Wireless Internet Communications (June 1-3, LuleĂĄ, Sweden)Proceeding of: 8th International Conference, WWIC 2010, Lulea, Sweden, June 1-3, 2010This paper addresses the topic of Fair QoE measurements in networking. The research of new solutions in networking is oriented to improve the user experience. Any application or service can be im- proved and the deployment of new solutions is mandatory to get the user satisfaction. However, different solutions exist; thus, it is necessary to select the most suitable ones. Nevertheless, this selection is difficult to make since the QoE is subjective and the comparison among different technologies is not trivial. The aim of this paper is to give an overview on how to perform fair QoE measurements to facilitate the study and re- search of new networking solutions and paradigms. However, previously to address this problem, an overview about how networking affects to the QoE is provided.This work has been funded by the CONTENT NoE from the European Commission (FP6- 2005-IST-41) and by the Ministry of Science and Innovation under the CON- PARTE project (MEC, TEC2007-67966-C03-03/TCM) and T2C2 project grant (TIN2008-06739-C04-01).Publicad
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