Search results for "Fault"

FDAE: A f̲ailure d̲etector for a̲synchronous e̲vents

2010

Transient stability simulation of a fixed speed wind turbine by Matlab/Simulink

2007

This paper describes the dynamic behavior of a typical fixed speed wind turbine connected to the grid; the model is developed in the simulation tool Matlab/Simulink and created as a modular structure. The pitch control system is used for stabilization of the wind turbine at grid faults. In this way, voltage stability of the system with grid-connected wind turbines can be improved by using blade-angle control for a temporary reduction of the wind turbine power during a short-circuit fault in the grid. This paper shows a new variable control for maintaining of voltage stability, when a three-phase fault is applied close to the wind turbine and cleared by disconnecting the affected line. In th…

Natural Laboratories for Field Observation About Genesis and Landscape Effects of Palaeo-Earthquakes: a Proposal for the Rocca Busambra and Monte Bar…

2018

Earthquakes are phenomena that are still being learned by the scientific community, and poorly known, especially as regards the prevention, by the population. Having a more complete knowledge is a basic step in understanding the vastness and intensity of the destructive phenomenon that involves a great amount of people. The recent earthquakes occurred in Central Italy (L’Aquila and Amatrice earthquakes) are examples that demonstrate the importance of having knowledge about these phenomena to contrast their destructive effects. We present a geological field trip to recognise causes and landscape effects of palaeo-earthquakes recorded in the Mesozoic rock successions outcropping in Sicily. Th…

A Discrete-Time Hazard Model for Loans: Some Evidence from Italian Banking System

2012

Problem statement: The probability of default, PD, is a crucial probl em for banks. In the last years international accords (Basel, Basel 2 an d Basel 3) have incentived banks to adopt objective s systems to evaluating and monitoring risk of defaul t in order to predict PD for new loans based on borrower's characteristics. The aim of this study i s to introduce a discrete survival model to study t he risk of default and to propose the empirical eviden ce by the Italian banking system. Approach: Survival analysis is used if we are interested in w hether and when an event occurs. In this context th e event occurrence represents a borrower's transition from one state, loan in bonis that is not…

Fracture Shape and Orientation Contributions to P-Wave Velocity and Anisotropy of Alpine Fault Mylonites

2021

P-wave anisotropy is significant in the mylonitic Alpine Fault shear zone. Mineral- and texture-induced anisotropy are dominant in these rocks but further complicated by the presence of fractures. Electron back-scattered diffraction and synchrotron X-ray microtomography (micro-CT) data are acquired on exhumed schist, protomylonite, mylonite and ultramylonite samples to quantify mineral phases, crystal preferred orientations, microfractures and porosity. The samples are composed of quartz, plagioclase, mica and accessory garnet, and contain 3-5% porosity. Based on the micro-CT data, the representative pore shape has an aspect ratio of 5:2:1. Two numerical models are compared to calculate the…

Ļaunprātīgas rīcības jēdziens Ženēvas 1956. gada 19. maija Konvencijā "Par kravu starptautisko autopārvadājumu līgumu (CMR)."

2015

CMR konvencijā pārvadātāju atbildība par pilnīgu vai daļēju kravas zaudējumu ir ierobežota. Tomēr 29. pantā ir ietverts izņēmums, kad pārvadātāja atbildība netiek ierobežota. 29. panta redakcija pieļauj ļoti atšķirīgu izpratni attiecībā uz to, kādos gadījumos pārvadātājs ir jāatbrīvo no atbildības. Darba mērķis ir padziļināti izpētīt ļaunprātīgas un tai pielīdzināmas rīcības jēdziena saturu, salīdzinot jēdziena izpratni Rietumeiropas valstīs un Latvijā. Darba ietvaros autors veiks konvencijas 29. panta teleoloģiskā un vēsturisko interpretāciju, kā arī aplūkos un analizēs valstu tiesu praksi 29. panta piemērošanā. Darba rezultāts ir izstrādāts pētījums, kurā ir uzskatāmi salīdzināta valstu i…

The Comparison of Software Reliability Assessment Models

2015

Abstract The reliability of the software represents one of the most important attributes of software quality, and the estimation of the reliability of the software is a problem hard to solve with accuracy. Nevertheless, in order to manage the quality of the software and of the standard practices in an organization, it is important to achieve an estimation of the reliability as accurate as possible. In the present work there are described the principles and techniques which underlie the estimation of the reliability of the software, starting from the definition of the concepts which express the attributes of software quality. It is taken into account the issue of the estimation of a software…

Emulating the Effects of Radiation-Induced Soft-Errors for the Reliability Assessment of Neural Networks

2021

International audience; Convolutional Neural Networks (CNNs) are currently one of the most widely used predictive models in machine learning. Recent studies have demonstrated that hardware faults induced by radiation fields, including cosmic rays, may significantly impact the CNN inference leading to wrong predictions. Therefore, ensuring the reliability of CNNs is crucial, especially for safety-critical systems. In the literature, several works propose reliability assessments of CNNs mainly based on statistically injected faults. This work presents a software emulator capable of injecting real faults retrieved from radiation tests. Specifically, from the device characterisation of a DRAM m…

The Identification of Single Phase to Earth Faults in Overhead Lines of Electrical Power Distribution Systems

2005

Service continuity is one of the aspects of greater importance in the definition of the quality of electrical energy. After the electrical energy market liberalization, distributors have moved towards new investments in research, first of all in the field of faults diagnostic. The Authors have already studied the problem of the service continuity and this paper represents the development of the research carried out in the field. The paper presents the extension, to overhead distribution lines, of the new diagnostic approach to identify, locate and characterize the faulty events, made up by the Authors. The proposed methodology must be integrated in an electrical distribution networks manage…

Preliminary results of fault-related permeability structures associated to the Scicli-Ragusa fault segments, Hyblean Plateau, Sicily

2010

Nella zona di Ragusa (Plateau Ibleo, Sicilia sud-orientale) la presenza di bitume all’interno di rocce carbonatiche di età oligo-miocenica, caratterizzate da una porosità primaria oggi compresa tra 0 e 10% (Formazione Ragusa, permette di osservare il ruolo esercitato da faglie e fratture nella circolazione degli idrocarburi. Con l’obiettivo quindi di effettuare studi mirati alla caratterizzazione petrofisica delle diverse tipologie di faglie e fratture affioranti, è stato condotto uno studio di terreno preliminare, che ha permesso la definizione dell’assetto geologico-strutturale della porzione occidentale del Plateau Ibleo, lungo il sistema di faglie denominato Scicli-Ragusa. Inoltre, sull…