Search results for "Turin"

Validation of a New Method for the Diagnosis of Rotor bar Failures via Wavelet Transformation in Industrial Induction Machines

2006

[EN] In this paper, the authors propose a method for the diagnosis of rotor bar failures in induction machines, based on the analysis of the stator current during the startup using the discrete wavelet transform (DWT). Unlike other approaches, the study of the high-order wavelet signals resulting from the decomposition is the core of the proposed method. After an introduction of the physical and mathematical bases of the method, a description of the proposed approach is given; for this purpose, a numerical model of induction machine is used in such a way that the effects of a bar breakage can clearly be shown, avoiding the influence of other phenomena not related with the fault. Afterward, …

The Use of the Wavelet Approximation Signal as a Tool for the Diagnosis of Rotor Bar Failures

2005

[EN] The aim of this paper is to present a new approach for rotor bar failure diagnosis in induction machines. The method focuses on the study of an approximation signal resulting from the wavelet decomposition of the startup stator current. The presence of the left sideband harmonic is used as evidence of the rotor failure in most diagnosis methods based on the analysis of the stator current. Thus, a detailed description of the evolution of the left sideband harmonic during the startup transient is given in this paper; for this purpose, a method for calculating the evolution of the left sideband during the startup is developed, and its results are physically explained. This paper also show…

Fractional wavelet transform

1997

The wavelet transform, which has had a growing importance in signal and image processing, has been generalized by association with both the wavelet transform and the fractional Fourier transform. Possible implementations of the new transformation are in image compression, image transmission, transient signal processing, etc. Computer simulations demonstrate the abilities of the novel transform. Optical implementation of this transform is briefly discussed.

Two-dimensional wavelet transform by wavelength multiplexing

1996

The wavelet transform is a useful tool for data compression, analysis of short transient pulses, optical correlators, etc. This transform was obtained optically by the use of the spatial or temporal multiplexing approaches. A two-dimensional wavelet transform is obtained with only one spatial channel. The information of the different scalings is carried in different wavelengths and summed incoherently at the output plane. Laboratory experimental results are demonstrated.

Criteria for Selecting Restructuring Strategies for Distressed or Declining Enterprises

2005

This paper seeks to determine the criteria for choosing restructuring strategies for declining or distressed enterprises. First, the paper differentiates between different stages of decline and different levels of distress, of which bankruptcy is an application. Second, it reviews the different forms of restructuring appearing in the academic literature. Third, it formalizes a descriptive model of determining restructuring applicable to distressed and declining enterprises. Specifically, the selection of a restructuring strategy is influenced not only be general restructuring criteria (firm-specific factors, the environment and characteristics of different restructuring) but also by the dec…

Production Planning in Production Networks: Models for Medium and Short-term Planning

2008

Distributed production networks are structures which are considered able to provide the organisational agility and efficiency necessary to compete in the global market. The performance of such organisations heavily depends on the ability of those involved in the network to coordinate their activities. Two approaches are available for managing complex distributed production networks: a centralised approach, where a unique entity (the planner, for instance) has all the necessary information to make planning decisions for the entire network; or a decentralised approach where each entity in the network has the necessary information and knowledge to make autonomous planning decisions, while the …

Results of a literature review on methods for estimating buildings energy demand at district level

2019

Abstract In the framework of distributed energy planning, evaluating reliable energy profiles of different sectors has a prominent role. At the same time, it is a quite challenging task, since the availability of actual energy profiles of buildings at the district level is not widespread. A survey of over 70 studies in scientific literature has been accomplished and a set of criteria has been defined for classifying the selected contributions based on the energy demand data features, source and/or estimation methods, highlighting the ones adopting hourly energy profiles. As final results, tables summarizing the main methods characteristics and a selection of studies providing directly useab…

Tabu search with strategic oscillation for the quadratic minimum spanning tree

2014

The quadratic minimum spanning tree problem consists of determining a spanning tree that minimizes the sum of costs of the edges and pairs of edges in the tree. Many algorithms and methods have been proposed for this hard combinatorial problem, including several highly sophisticated metaheuristics. This article presents a simple Tabu Search (TS) for this problem that incorporates Strategic Oscillation (SO) by alternating between constructive and destructive phases. The commonalties shared by this strategy and the more recently introduced methodology called iterated greedy search are shown and implications of their differences regarding the use of memory structures are identified. Extensive …

Epidermal Growth Factor Receptors and Downstream Signalling Pathways as Cancer Treatment Targets for Medicinal Plants

2015

Determination of Pareto frontier in multi-objective maintenance optimization

2011

Abstract The objective of a maintenance policy generally is the global maintenance cost minimization that involves not only the direct costs for both the maintenance actions and the spare parts, but also those ones due to the system stop for preventive maintenance and the downtime for failure. For some operating systems, the failure event can be dangerous so that they are asked to operate assuring a very high reliability level between two consecutive fixed stops. The present paper attempts to individuate the set of elements on which performing maintenance actions so that the system can assure the required reliability level until the next fixed stop for maintenance, minimizing both the globa…