Search results for "machines"
showing 10 items of 113 documents
What is the Natural Abstraction Level of an Algorithm?
2021
Abstract State Machines work with algorithms on the natural abstraction level. In this paper, we discuss the notion of the natural abstraction level of an algorithm and how ASM manage to capture this abstraction level. We will look into three areas of algorithms: the algorithm execution, the algorithm description, and the algorithm semantics. We conclude that ASM capture the natural abstraction level of the algorithm execution, but not necessarily of the algorithm description. ASM do also capture the natural abstraction level of execution semantics.
Distributed Computing on Distributed Memory
2018
Distributed computation is formalized in several description languages for computation, as e.g. Unified Modeling Language (UML), Specification and Description Language (SDL), and Concurrent Abstract State Machines (CASM). All these languages focus on the distribution of computation, which is somewhat the same as concurrent computation. In addition, there is also the aspect of distribution of state, which is often neglected. Distribution of state is most commonly represented by communication between active agents. This paper argues that it is desirable to abstract from the communication and to consider abstract distributed state. This includes semantic handling of conflict resolution, e.g. i…
A General Mathematical Formulation for Winding Layout Arrangement of Electrical Machines
2018
Winding design methods have been a subject of research for many years of the past century. Many methods have been developed, each one characterized by some advantages and drawbacks. Nowadays, the star of slots is the most widespread design tool for electrical machine windings. In this context, this paper presents a simple and effective procedure to determine the distribution of the slot EMFs over the phases and of the winding configuration in all possible typologies of electrical machines equipped with symmetrical windings. The result of this procedure gives a Winding Distribution Table (WDT), which can be used to define coils and coil groups connections and also to simply implement winding…
A General Investigation on the Differential Leakage Factor for Symmetrical and Asymmetrical Multiphase Winding Design
2020
This work provides an investigation based on a fast estimation of the degree of unbalance (D.U.%) and the differential leakage factor (&sigma
Design and Experimental Test of a Thermomagnetic Motor
2012
Abstract This paper presents a Thermomagnetic Motor. The design of the motor is based on a thermal-magnetic coupled dynamic model, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the curie point. The motor is modeled in terms of both its magnetic as well thermal properties (magnetic permeability and thermal conductivity) and the thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is p…
Evaluation of a Support Vector Machine Based Method for Crohn’s Disease Classification
2019
Crohn’s disease (CD) is a chronic, disabling inflammatory bowel disease that affects millions of people worldwide. CD diagnosis is a challenging issue that involves a combination of radiological, endoscopic, histological, and laboratory investigations. Medical imaging plays an important role in the clinical evaluation of CD. Enterography magnetic resonance imaging (E-MRI) has been proven to be a useful diagnostic tool for disease activity assessment. However, the manual classification process by expert radiologists is time-consuming and expensive. This paper proposes the evaluation of an automatic Support Vector Machine (SVM) based supervised learning method for CD classification. A real E-…
A general procedure for the construction of Gorges polygons for multi-phase windings of electrical machines
2018
This paper presents a simple and effective procedure for the determination of the Gorges polygon, suitable for all possible winding configurations in electrical machines. This methodology takes into account the determination of a Winding Distribution Table (WDT), in which all the information about the distribution of the currents along the stator periphery is computed and from which the Görges polygon are easily derived. The proposed method can be applied to both symmetrical and asymmetrical multi-phase windings, including concentrated, fractional, reduced and dead-coil ones. The examples provided in this paper demonstrate the versatility of the proposed method.
Control and design for efficiency improvement of permanent-magnet synchronous motor drives in household appliances
2011
This paper deals with some aspects of efficiency improvement of PMSMD (Permanent Magnet Synchronous Motor Drives). Particularly two aspects are focused: the control algorithm for the PMSMD, which allows to reduce the power losses of the electric drive without penalty on its dynamic performances and the optimization of an IPMSM (Interior Permanent Magnet Synchronous Motor) rotor configuration capable to increase the performances in terms of shaft torque production, limiting at the same time the rotor leakage flux. The loss minimization algorithm is here briefly analyzed, a test bed for experimental validation is presented and the data are analyzed. Experimental tests have been performed aimi…
Vibrations of a continuous web on elastic supports
2017
We consider an infinite, homogenous linearly elastic beam resting on a system of linearly elastic supports, as an idealized model for a paper web in the middle of a cylinder-based dryer section. We obtain closed-form analytical expressions for the eigenfrequencies and the eigenmodes. The frequencies increase as the support rigidity is increased. Each frequency is bounded from above by the solution with absolutely rigid supports, and from below by the solution in the limit of vanishing support rigidity. Thus in a real system, the natural frequencies will be lower than predicted by commonly used models with rigid supports. peerReviewed
D-Q axis theory of thermomagnetic Curie motor
2010
This paper presents a the d-q axis theory of a thermomagnetic Curie motor. From this theory a maximization procedure of the performances of Curie motor has been developed. The proposed approach has shown that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a d.c. electric machine. Consequently, a design of a Curie motor has been proposed and the calculated performances show a significant improvement in comparison to the performances reported in literature.