Search results for "testing"
showing 10 items of 1769 documents
An Innovative Coupling Solution for Power Line Communication in MV Electrical Networks
2019
One of the main problems in the diffusion of power line communication (PLC) in medium voltage (MV) networks is the need of a dedicated PLC coupler to be installed all over the network. To avoid this problem, the authors have studied, prototyped and patented an innovative PLC coupling solution which uses electrical elements embedded in most of the switchgears already installed in MV networks, i.e. the capacitive dividers of the voltage detecting systems (VDS). The new solution prototype is described in this paper, highlighting the advantages in terms of a significant reduction of both direct costs of equipment and infrastructures and indirect costs of installation and service interruption. T…
Simulation of a Power Line Communication System in Medium and Low Voltage Distribution Networks
2011
The aim of the paper is to study the influence of the power transformer on signal transmission in the case of a power line communication (PLC) system in a overhead Medium Voltage (MV) power network. A model of the PLC system was carried out by means of the Simulink® software. A distributed parameter MV overhead line, two power transformers, the signal coupling networks and the receiving and transmitting line coupling interface of a ST7540 FSK powerline transceiver were included in the model. The performances of the complete PLC communication system are evaluated for different line lengths by means of the attenuation computed as ratio between the received and transmitted voltage signals.
An Innovative Power Line Communication solution For Medium Voltage Smart Grids Applications
2018
This paper summarizes the authors research activity concerning the design, modeling and experimental characterization of a new coupling system for medium voltage (MV) narrow band power line communications (NB-PLC). The proposed solution has been patented by authors and it exploits the capacitive divider of voltage detecting systems (VDSs) normally used to reveal the mains voltage presence, thus avoiding the use of dedicated MV couplers. In the following, the modeling of the VDS capacitive divider is presented and the interface card design is described, based on simulation of the whole PLC transmission channel. Laboratory tests are also presented. Finally, the results are shown of an on-fiel…
Comparison of Post-Weld Treatment of High-Strength Steel Welded Joints in Medium Cycle Fatigue
2010
This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel. The processes investigated are: burr grinding, TIG dressing and ultrasonic impact treatment. The focus of this investigation is on the so-called medium cycle area, i.e. 10 000-500 000 cycles and very high stress ranges. In this area of fatigue design, the use of very high strength steel becomes necessary, since the stress range can exceed the yield-strength of ordinary structural steel, especially when consi…
Editorial: Scale Development and Score Validation
2020
DigiTala research project : automatic speech recognition in assessing L2 speaking
2020
In this article, we discuss the premise of assessing oral language skills with the help of automatic speech recognition. We present the main goals and working methods in DigiTala project (2019–2023) – a research project between University of Helsinki, Aalto University and University of Jyväskylä that aims at developing a digital tool for assessing and practicing oral language skills. Ultimately, this digital tool would enable implementing tasks measuring oral skills into the language tests of the Matriculation Examination. nonPeerReviewed
Why is the hypothetico-deductive (H-D) method in information systems not an H-D method?
2020
The hypothetico-deductive (H-D) method is reported to be common in information systems (IS). In IS, the H-D method is often presented as a Popperian, Hempelian, or natural science method. However, there are many fundamental differences between what Popper or Hempel actually say and what the alleged H-D method per Hempel or per Popper means in IS. To avoid possible misunderstanding and conceptual confusion about the basic philosophical concepts, we explain some of these differences, which are not mentioned in IS literature describing the H-D model. Due to these distinctive differences, the alleged H-D method per Hempel or per Popper in IS cannot be regarded as the H-D model per Hempel or per…
A methodology for the control of the residual lifetimes of carbon fibre reinforced composite pressure vessels
2005
International audience; Pressure vessels must be periodically proof tested. Traditional techniques for metal vessels are inapplicable for composite vessels as the latter do not break by crack propagation so that the reasoning behind the traditional testing procedures is not appropriate. Damage accumulation leading to the degradation of a composite vessel is by fibre failure. Fibres show a wide distribution in strengths and loading a composite inevitably breaks some. The method which has been developed is supported by an analysis of delayed fibre failure due to the relaxation of the resin around fibre breaks. This provokes overloading of intact fibres neighbouring breaks. The time until a cr…
Corrigendum: ExGUtils: A Python Package for Statistical Analysis With the ex-Gaussian Probability Density
2018
Two‐sample problems in statistical data modelling
2010
A common problem in mathematical statistics is to check whether two samples differ from each other. From modelling point of view it is possible to make a statistical test for the equality of two means or alternatively two distribution functions. The second approach allows to represent the two‐sample test graphically. This can be done by adding simultaneous confidence bands to the probability‐probability (P — P) or quantile‐quantile (Q — Q) plots. In this paper we compare empirically the accuracy of the classical two‐sample t‐test, empirical likelihood method and several bootstrap methods. For a real data example both Q — Q and P — P plots with simultaneous confidence bands have been plotted…