Search results for "Isola"
showing 10 items of 818 documents
The Role of Social and Collaborative Networks in the Development of in-House Multimedia Language Learning Materials
2012
The development of in-house language learning materials has being going on for many decades. In the past, it was difficult for language teachers worldwide to share their in-house materials with other teachers, and so was having access to the materials developed by others. This often produced a feeling of isolation and, very frequently, provoked a duplication of efforts and a bigger investment of time. However, thanks to the Web 2.0 teachers and practitioners worldwide can communicate with each other and share experiences and materials. While this aspect of the so-called Social Web has being successfully exploded in the past few decades, especially in the case of online communities of teache…
A two-stage fault detection and classification for electric pitch drives in offshore wind farms using support vector machine
2017
This article presents a two-stage fault detection and classification scheme, for induction motor drives in wind turbine pitch systems. The presented approach is suitable for application in offshore wind farms. The adopted strategy utilizes three phase motor current sensing at the pitch drives for fault detection and only when a fault is detected at this stage, features extracted from the current signals are transmitted to a central support vector machine classifier. The proposed method is validated in a laboratory setup of the pitch drive.
Data-driven design of robust fault detection system for wind turbines
2014
Abstract In this paper, a robust data-driven fault detection approach is proposed with application to a wind turbine benchmark. The main challenges of the wind turbine fault detection lie in its nonlinearity, unknown disturbances as well as significant measurement noise. To overcome these difficulties, a data-driven fault detection scheme is proposed with robust residual generators directly constructed from available process data. A performance index and an optimization criterion are proposed to achieve the robustness of the residual signals related to the disturbances. For the residual evaluation, a proper evaluation approach as well as a suitable decision logic is given to make a correct …
Arc Fault Detection Method Based on CZT Low-Frequency Harmonic Current Analysis
2017
This paper presents a method for the detection of series arc faults in electrical circuits, which has been developed starting from an experimental characterization of the arc fault phenomenon and an arcing current study in several test conditions. Starting from this, the authors have found that is it possible to suitably detect arc faults by means of a high-resolution low-frequency harmonic analysis of current signal, based on chirp zeta transform, and a proper set of indicators. The proposed method effectiveness is shown by means of experimental tests, which were carried in both arcing and nonarcing conditions and in the presence of different loads, chosen according to the UL 1699 standard…
Barriers to Integrated Marketing Communications: The Case of Latvia (small markets)
2012
Abstract No promotional tool should be used in isolation or without regard to the others; hence there is a trend toward integrated marketing communications. Many conclusions of researchers and most of the studies justify the effectiveness of the IMC and point to multiple advantages in comparison to the classical MC. In comparison to the classical MC, the IMC also in small markets declare exigency and ensure higher effectiveness. But the development and application of the IMC also has several problems or barriers. The purpose of this study is to investigate barriers to Integrated Marketing Communications in Latvian market (small markets). According to accomplished interrogation, the most imp…
A robust fault detection design for uncertain Takagi-Sugeno models with unknown inputs and time-varying delays
2013
Abstract This paper investigates the problem of robust fault detection system design for a class of uncertain Takagi–Sugeno (T–S) models. The system under consideration is subject to unknown input and time-varying delay. The fault detection system is designed such that the unknown input is thoroughly decoupled from residual signals generated by the fault detection system. Furthermore, the residual signals show the maximum possible sensitivity to the faults and the minimum possible sensitivity to the external disturbances. The model matching approach is utilized to tackle the effects of parametric uncertainties in the model of the system. The design procedure is presented in terms of Linear …
A structured filter for Markovian switching systems
2014
In this work, a new methodology for the structuring of multiple model estimation schemas is developed. The proposed filter is applied to the estimation and detection of active mode in dynamic systems. The discrete-time Markovian switching systems represented by several linear models, associated with a particular operating mode, are studied. Therefore, the main idea of this work is the subdivision of the models set to some subsets in order to improve the detection and estimation performances. Each subset is associated with sub-estimators based on models of the subset. In order to compute the global estimate and subset probabilities, a global estimator is proposed. Theoretical developments ba…
A DRO-based X-band injection-locked amplifier without input non-reciprocal elements
2009
Conventional design of injection-locked amplifiers (ILA's) implies the use of a non-reciprocal (ferrite, usually) element for separating the input signal from the synchronized output signal. In this paper a novel topological structure is proposed which permitted the realization of a wide-band, transmission-type, ILA with no need for separating input-port isolator or preamplifier. The prototype, realized in HMIC technology, while intended only as demonstrator of the newly proposed approach in the design of ILA's, shows quite satisfactory performances at X-band, with a simple, compact and low-cost structure.
A Geometrical Simple Approach for Power Silicon Devices Fault Detection and Fault-Tolerant Operation of a Voltage Source Inverter
2012
Fault-tolerant converters have been widely investigated for years and nowadays an extensive technical literature on this field exists. This paper presents a novel fault detection algorithm based on a simple geometrical approach. In the algorithm analysis both the case of faults in single device and the lose of an entire inverter leg have been considered. False positive detections are avoided by considering a proper number of current samples. The proposed fault detection algorithm is characterized by simplicity, low computational and implementation effort with a consequent enough fast execution, easy control integration with the possibility to use it both in hardware in the loop systems and …
ANALYSIS OF DIFFERENT VISUAL STRATEGIES OF 'ISOLATED VEHICLE' AND 'DISTURBED VEHICLE'
2017
This paper analyses the driver’ visual behaviour in the different conditions of ‘isolated vehicle’ and ‘disturbed vehicle’. If the meaning of the former is clear, the latter condition considers the influence on the driving behaviour of various objects that could be encountered along the road. These can be classified in static (signage, stationary vehicles at the roadside, etc.) and dynamic objects (cars, motorcycles, bicycles). The aim of this paper is to propose a proper analysis regarding the driver’s visual behaviour. In particular, the authors examined the quality of the visually informa-tion acquired from the entire road environment, useful for detecting any critical safety condition. …