Etude et simulation des groupes convertisseurs-machines synchrones a six phases
Doyon, Jean-Francois
Since many years, multiphase (n > 3) machines represent a growing research interest in the electrical machines domain. This type of machine can be used for many systems like automotive electrical traction, electric ship propulsion, wind farms or high-power industrial applications. Above all multiphase machines, the six phases wounded rotor synchronous machine brings a huge interest. Subsequently, using that kind of machine in any application requires a good understanding of the machine model and its respective converters. Hence, simulation represents a great way to study the behaviour and design of such applications that uses six phases wounded rotor synchronous machines. The present research concerns the study and simulation of six phase synchronous machinesconverters systems. From this project resulted the implementation of the six phases wound rotor salient pole synchronous machine in the Demos library of Matlab SimPowerSytems. In terms of study, a six phase machine electric drive is designed as well as a six phase machine implementation in a type 4 wind farm. The modeling of the six phase synchronous machine is fully detailed for the electrical part and the mechanical part. Then, the voltage source inverter electric drive with hysteresis control is conceived. Simulations of torque control, speed control and degraded mode of the machine are executed. The results illustrate the electric drive efficiency. This is followed by the type 4 wind turbine application of the machine. The wind farm is connected to a 120 kV grid, where a voltage drop fault appears at the 120 kV bar for a duration of six 60 Hz cycles. The results show a good operation of the regulators during the fault. This application is also subjected to a degraded mode, where results illustrate once again a good system regulation. Also, for the electric drive and the wind farm applications, a comparative study is made for the use of an asymmetrical versus symmetrical winding configuration of the machine
Asynchronized synchronous machines
Botvinnik, M M
1964-01-01
Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv
Analysis of synchronous machines
Lipo, TA
2012-01-01
Analysis of Synchronous Machines, Second Edition is a thoroughly modern treatment of an old subject. Courses generally teach about synchronous machines by introducing the steady-state per phase equivalent circuit without a clear, thorough presentation of the source of this circuit representation, which is a crucial aspect. Taking a different approach, this book provides a deeper understanding of complex electromechanical drives. Focusing on the terminal rather than on the internal characteristics of machines, the book begins with the general concept of winding functions, describing the placeme
Energy Technology Data Exchange (ETDEWEB)
Amara, Y.
2001-12-01
Double excitation machines are synchronous machines where two excitation circuits coexist: one with permanent magnets and the other with windings. This study shows that double excitation allows to combine the advantages of synchronous machines with winded inductor with those of permanent magnet machines. This concept allows a better dimensioning of the converter-machine set and a better energy management. In order to allow the operation of permanent magnet machines over a wide range of speeds, it is necessary to have a magnetic reaction of the induced circuit of the same order than the excitation flux. On the other hand, the power factor is weaker and the power supply converter is over-dimensioned. The double excitation allows the permanent magnet machines to work over a large speed range with a better power factor, even when the magnetic reaction of the induced circuit is relatively weak with respect to the excitation flux. (J.S.)
Online Dynamic Parameter Estimation of Synchronous Machines
West, Michael R.
Traditionally, synchronous machine parameters are determined through an offline characterization procedure. The IEEE 115 standard suggests a variety of mechanical and electrical tests to capture the fundamental characteristics and behaviors of a given machine. These characteristics and behaviors can be used to develop and understand machine models that accurately reflect the machine's performance. To perform such tests, the machine is required to be removed from service. Characterizing a machine offline can result in economic losses due to down time, labor expenses, etc. Such losses may be mitigated by implementing online characterization procedures. Historically, different approaches have been taken to develop methods of calculating a machine's electrical characteristics, without removing the machine from service. Using a machine's input and response data combined with a numerical algorithm, a machine's characteristics can be determined. This thesis explores such characterization methods and strives to compare the IEEE 115 standard for offline characterization with the least squares approximation iterative approach implemented on a 20 h.p. synchronous machine. This least squares estimation method of online parameter estimation shows encouraging results for steady-state parameters, in comparison with steady-state parameters obtained through the IEEE 115 standard.
Sensorless Control of Permanent Magnet Synchronous Machines
DEFF Research Database (Denmark)
Matzen, Torben N.
to appear. Sensorless control implies control of the machine without using a direct measurement of the rotor position. Instead, more information is extracted from the existing controller feedback signals - often the machine currents - and this information is used together with accurate system knowledge...... machine is also used for servo applications where higher dynamics is required, e.g. in industrial automation. The energy efficiency is essential for battery powered electric vehicles where the electric storage capacity is limited by cost, mass and volume. The control system necessary to operate...... the synchronous machine requires knowledge of the rotor shaft position due to the synchronous and undamped nature of the machine. The rotor position may be measured using a mechanical sensor, but the sensor reduces reliability and adds cost to the system and for this reason sensorless control methods started...
International Electrotechnical Commission. Geneva
1985-01-01
Applies to three-phase synchronous machines of 1 kVA rating and larger with rated frequency of not more than 400 Hz and not less than 15 Hz. An appendix gives unconfirmed test methods for determining synchronous machine quantities. Notes: 1 -Tests are not applicable to synchronous machines such as permanent magnet field machines, inductor type machines, etc. 2 -They also apply to brushless machines, but certain variations exist and special precautions should be taken.
Modeling of synchronous machines with magnetic saturation
Energy Technology Data Exchange (ETDEWEB)
Rehaoulia, H. [Universite de Tunis-Ecole Superieure des Sciences et Techniques de Tunis (Unite de Recherche CSSS), 5 Avenue Taha Hussein Tunis 10008 (Tunisia); Henao, H.; Capolino, G.A. [Universite de Picardie Jules Vernes-Centre de Robotique, d' Electrotechnique et d' Automatique (UPRES-EA3299), 33 Rue Saint Leu, 80039 Amiens Cedex 1 (France)
2007-04-15
This paper deals with a method to derive multiple models of saturated round rotor synchronous machines, based on different selections of state-space variables. By considering the machine currents and fluxes as space vectors, possible d-q models are discussed and adequately numbered. As a result several novel models are found and presented. It is shown that the total number of d-q models for a synchronous machine, with basic dampers, is 64 and therefore much higher than known. Found models are classified into three families: current, flux and mixed models. These latter, the mixed ones, constitute the major part (52) and hence offer a large choice. Regarding magnetic saturation, the paper also presents a method to account for whatever the choice of state-space variables. The approach consists of just elaborating the saturation model with winding currents as main variables and deriving all the other models from it, by ordinary mathematical manipulations. The paper emphasizes the ability of the proposed approach to develop any existing model without exception. An application to prove the validity of the method and the equivalence between all developed models is reported. (author)
Energy Technology Data Exchange (ETDEWEB)
Kouadio, L.
1996-12-12
A new method for spark-ignition engine control, more especially in idle conditions, has been developed to prevent engine stalling and improve its idling performances in terms of fuel consumption and pollutant emissions: the car synchronous machine, traditionally operating as an alternator, is used in certain phases to provide an external supplementary torque on the engine shaft. Methods are proposed for optimising the synchronous machine operation as a generator and as an engine, then the main engine control parameters are presented and a linear signal model is established around a nominal idling point, which is used for simulations. Experimental results show evident reductions of fuel consumption and a significant robustness improvement in the engine dynamics
Is whole-culture synchronization biology's 'perpetual-motion machine'?
Cooper, Stephen
2004-06-01
Whole-culture or batch synchronization cannot, in theory, produce a synchronized culture because it violates a fundamental law that proposes that no batch treatment can alter the cell-age order of a culture. In analogy with the history of perpetual-motion machines, it is suggested that the study of these whole-culture 'synchronization' methods might lead to an understanding of general biological principles even though these methods cannot be used to study the normal cell cycle.
Vectorial Formalism of Polyphase Synchronous Machine With Permanents Magnets
Directory of Open Access Journals (Sweden)
Nacéra Bachir Bouiadjra
2013-04-01
Full Text Available This paper presents a mathematical model that transforms the real machine to fictitious machines and our goal is to simulate these and see the behavior of these machines in load. The polyphase machines are developed mainly in the field of variable speed drives of high power because increasing the number of phases on the one hand allows to reduce the dimensions of the components in power modulators energy and secondly to improve the operating safety. By a vector approach (vector space, it is possible to find a set of single-phase machine and / or two-phase fictitious equivalent to polyphase synchronous machine. These fictitious machines are coupled electrically and mechanically but decoupled magnetically. This approach leads to introduce the concept of the equivalent machine (multimachine multiconverter system MMS which aims to analyze systems composed of multiple machines (or multiple converters in electric drives. A first classification multimachine multiconverter system follows naturally from MMS formalism. We present an example of a pentaphase (polyphase synchronous machine for a simulation and study the behavior of the machine load
Variable-Speed, Robust Synchronous Reluctance Machine Drive Systems
DEFF Research Database (Denmark)
Wang, Dong
The synchronous reluctance machine drive is getting more and more interests from the industrial side, since it can provide higher system energy efficiency than traditional inverter-fed induction machine drive systems with similar production cost. It is considered as a good candidate for super...... premium efficiency machine and commercial products are available in the market. The research work in this dissertation aims at developing a simple, compact and robust synchronous reluctance machine drive system that can provide satisfactory performance with optimized system energy efficiency at various...... working conditions. Field oriented control assisted with various position estimation algorithms is in-vestigated. Position sensing via machine flux linkage is implemented with the assistance of a widely used flux observer. Experiments show that it may not always work properly and system oscillation...
Sensorless Control of Permanent Magnet Synchronous Machines
DEFF Research Database (Denmark)
Matzen, Torben N.
Permanent magnet machines, with either surface mounted or embedded magnets on the rotor, are becoming more common due to the key advantages of higher energy conversion efficiency and higher torque density compared to the classical induction machine. Besides energy efficiency the permanent magnet...... are dependent on the phase currents and rotor position. Based on the flux linkages the differential inductances are determined and used to establish the inductance saliency in terms of ratio and orientation. The orientation and its dependence on the current and rotor position are used to analyse the behaviour...... and establish the suitability of the machine for sensorless control using inductance saliency tracking methods. The same electromagnetic behaviour is used in the implementation of a dynamical simulation model of the machine useful for evaluation of sensorless control methods at the control design stage. Further...
Magnetic equivalent circuit model for unipolar hybrid excitation synchronous machine
Directory of Open Access Journals (Sweden)
Kupiec Emil
2015-03-01
Full Text Available Lately, there has been increased interest in hybrid excitation electrical machines. Hybrid excitation is a construction that combines permanent magnet excitation with wound field excitation. Within the general classification, these machines can be classified as modified synchronous machines or inductor machines. These machines may be applied as motors and generators. The complexity of electromagnetic phenomena which occur as a result of coupling of magnetic fluxes of separate excitation systems with perpendicular magnetic axis is a motivation to formulate various mathematical models of these machines. The presented paper discusses the construction of a unipolar hybrid excitation synchronous machine. The magnetic equivalent circuit model including nonlinear magnetization curves is presented. Based on this model, it is possible to determine the multi-parameter relationships between the induced voltage and magnetomotive force in the excitation winding. Particular attention has been paid to the analysis of the impact of additional stator and rotor yokes on above relationship. Induced voltage determines the remaining operating parameters of the machine, both in the motor and generator mode of operation. The analysis of chosen correlations results in an identification of the effective control range of electromotive force of the machine.
Synchronization of Two Self-Synchronous Vibrating Machines on an Isolation Frame
Directory of Open Access Journals (Sweden)
Chunyu Zhao
2011-01-01
Full Text Available This paper investigates synchronization of two self-synchronous vibrating machines on an isolation rigid frame. Using the modified average method of small parameters, we deduce the non-dimensional coupling differential equations of the disturbance parameters for the angular velocities of the four unbalanced rotors. Then the stability problem of synchronization for the four unbalanced rotors is converted into the stability problems of two generalized systems. One is the generalized system of the angular velocity disturbance parameters for the four unbalanced rotors, and the other is the generalized system of three phase disturbance parameters. The condition of implementing synchronization is that the torque of frequency capture between each pair of the unbalanced rotors on a vibrating machine is greater than the absolute values of the output electromagnetic torque difference between each pair of motors, and that the torque of frequency capture between the two vibrating machines is greater than the absolute value of the output electromagnetic torque difference between the two pairs of motors on the two vibrating machines. The stability condition of synchronization of the two vibrating machines is that the inertia coupling matrix is definite positive, and that all the eigenvalues for the generalized system of three phase disturbance parameters have negative real parts. Computer simulations are carried out to verify the results of the theoretical investigation.
Energy Technology Data Exchange (ETDEWEB)
Benecke, Marcel; Lindemann, Andreas [Magdeburg Univ. (Germany). Inst. fuer Elektrische Energiesysteme; Griepentrog, Gerd [Siemens AG (Germany). Corporate Technology CT T DE
2011-07-01
Permanentmagnet synchronous machines (PMSM) show lower losses compared to induction machines (IM) due to the lack of rotor losses which are typical only for IM. Hence, for many applications with a fixed rotational speed such as fans or pumps the PMSM would be a good choice in case the PMSM is directly connected to the grid without any converter in between at nominal speed. This would be an optimal solution with respect to efficiency and losses. Because the PMSM is not able to speed up when directly connected to the grid, it has normally to be started using a frequency converter or it has to be equipped with a start-up short-circuit cage which would develop an asynchronous torque. A cost effective alternative is to use AC voltage controller or softstarter based on thyristors to speed up the PMSM and bridge the AC voltage controller once the PMSM has reached nominal speed. This paper presents a calculation method to predict the dynamic behaviour of a PMSM when fed by a thyristor-based AC voltage controller. (orig.)
Dynamic study of synchronous machine electric drive
Directory of Open Access Journals (Sweden)
Dimitar Spirov
2005-10-01
Full Text Available The dynamic behaviour of the fan blower synchoronous machine drive have been studied in the paper. The equations for the voltages of the synchoronous machine windings are presented in a coordinate system which rotates at the angular speed of the rotor. The mechanical equipment is presented by means of a single-mass dynamic model. The derived system of differential equations is transformed and solved using suitable software product. The results obtained for rotation frequency and electromagnetic torque motor in the courses of different values of rated supply voltage and of different initial resistant moment of the mechanism have been graphically presented. Conclusions from the results obtained have been done.
Mobile virtual synchronous machine for vehicle-to-grid applications
Energy Technology Data Exchange (ETDEWEB)
Pelczar, Christopher
2012-03-20
The Mobile Virtual Synchronous Machine (VISMA) is a power electronics device for Vehicle to Grid (V2G) applications which behaves like an electromechanical synchronous machine and offers the same beneficial properties to the power network, increasing the inertia in the system, stabilizing the grid voltage, and providing a short-circuit current in case of grid faults. The VISMA performs a real-time simulation of a synchronous machine and calculates the phase currents that an electromagnetic synchronous machine would produce under the same local grid conditions. An inverter with a current controller feeds the currents calculated by the VISMA into the grid. In this dissertation, the requirements for a machine model suitable for the Mobile VISMA are set, and a mathematical model suitable for use in the VISMA algorithm is found and tested in a custom-designed simulation environment prior to implementation on the Mobile VISMA hardware. A new hardware architecture for the Mobile VISMA based on microcontroller and FPGA technologies is presented, and experimental hardware is designed, implemented, and tested. The new architecture is designed in such a way that allows reducing the size and cost of the VISMA, making it suitable for installation in an electric vehicle. A simulation model of the inverter hardware and hysteresis current controller is created, and the simulations are verified with various experiments. The verified model is then used to design a new type of PWM-based current controller for the Mobile VISMA. The performance of the hysteresis- and PWM-based current controllers is evaluated and compared for different operational modes of the VISMA and configurations of the inverter hardware. Finally, the behavior of the VISMA during power network faults is examined. A desired behavior of the VISMA during network faults is defined, and experiments are performed which verify that the VISMA, inverter hardware, and current controllers are capable of supporting this
Variable-Speed, Robust Synchronous Reluctance Machine Drive Systems
DEFF Research Database (Denmark)
Wang, Dong
algorithm, the proposed machine inductance in-dependent position estimation algorithm shows better dynamic response against the step load changes but requires more accurate signal sampling in steady state. Therefore, the flux linkage based position estimation algorithm with adaptive PI controllers......The synchronous reluctance machine drive is getting more and more interests from the industrial side, since it can provide higher system energy efficiency than traditional inverter-fed induction machine drive systems with similar production cost. It is considered as a good candidate for super...... inductance independency. High frequency signal injection based on duty cycle shifting is introduced, which can achieve signal injection without sacrificing the maximum allowable fundamental voltage for torque production, so that the machine induct-ance independent position estimation algorithm can...
Machine Translation Using Constraint-Based Synchronous Grammar
Institute of Scientific and Technical Information of China (English)
WONG Fai; DONG Mingchui; HU Dongcheng
2006-01-01
A synchronous grammar based on the formalism of context-free grammar was developed by generalizing the first component of production that models the source text. Unlike other synchronous grammars,the grammar allows multiple target productions to be associated to a single production rule which can be used to guide a parser to infer different possible translational equivalences for a recognized input string according to the feature constraints of symbols in the pattern. An extended generalized LR algorithm was adapted to the parsing of the proposed formalism to analyze the syntactic structure of a language. The grammar was used as the basis for building a machine translation system for Portuguese to Chinese translation. The empirical results show that the grammar is more expressive when modeling the translational equivalences of parallel texts for machine translation and grammar rewriting applications.
Contrôle des Circuits Auxiliaires des PFW (arrêt machines 2002/2003)
Ottaviani, J
2003-01-01
Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d aimant et constituées d un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et pick-up brasés sur les enroulements). Pendant la variation du champ magnétique de l aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux courants de Foucault dans la chambre à vide. Chaque année, pendant l arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre pick-up et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, boucles ouvertes ou en court-circuit, déf...
Optimal Design Solutions for Permanent Magnet Synchronous Machines
Directory of Open Access Journals (Sweden)
POPESCU, M.
2011-11-01
Full Text Available This paper presents optimal design solutions for reducing the cogging torque of permanent magnets synchronous machines. A first solution proposed in the paper consists in using closed stator slots that determines a nearly isotropic magnetic structure of the stator core, reducing the mutual attraction between permanent magnets and the slotted armature. To avoid complications in the windings manufacture technology the stator slots are closed using wedges made of soft magnetic composite materials. The second solution consists in properly choosing the combination of pole number and stator slots number that typically leads to a winding with fractional number of slots/pole/phase. The proposed measures for cogging torque reduction are analyzed by means of 2D/3D finite element models developed using the professional Flux software package. Numerical results are discussed and compared with experimental ones obtained by testing a PMSM prototype.
Efficient operation of anisotropic synchronous machines for wind energy systems
Eldeeb, Hisham; Hackf, Christoph M.; Kullick, Julian
2016-09-01
This paper presents an analytical solution for the Maximum-Torque-per-Ampere (MTPA) operation of synchronous machines (SM) with anisotropy and magnetic cross-coupling for the application in wind turbine systems and airborne wind energy systems. For a given reference torque, the analytical MTPA solution provides the optimal stator current references which produce the desired torque while minimizing the stator copper losses. From an implementation point of view, the proposed analytical method is appealing in terms of its fast online computation (compared to classical numerical methods) and its efficiency enhancement of the electrical drive system. The efficiency of the analytical MTPA operation, with and without consideration of cross-coupling, is compared to the conventional method with zero direct current.
Modelling and Simulation of a Synchronous Machine with Power Electronic Systems
DEFF Research Database (Denmark)
Chen, Zhe; Blaabjerg, Frede
2005-01-01
This paper reports the modeling and simulation of a synchronous machine with a power electronic interface in direct phase model. The implementation of a direct phase model of synchronous machines in MATLAB/SIMULINK is presented .The power electronic system associated with the synchronous machine...... is modelled in SIMULINK as well. The resulting model can more accurately represent non-idea situations such as non-symmetrical parameters of the electrical machines and unbalance conditions. The model may be used for both steady state and large-signal dynamic analysis. This is particularly useful...
Modelling and Simulation of a Synchronous Machine with Power Electronic Systems
DEFF Research Database (Denmark)
Chen, Zhe; Blaabjerg, Frede
2005-01-01
This paper reports the modeling and simulation of a synchronous machine with a power electronic interface in direct phase model. The implementation of a direct phase model of synchronous machines in MATLAB/SIMULINK is presented .The power electronic system associated with the synchronous machine...... is modelled in SIMULINK as well. The resulting model can more accurately represent non-idea situations such as non-symmetrical parameters of the electrical machines and unbalance conditions. The model may be used for both steady state and large-signal dynamic analysis. This is particularly useful...
Methods, systems and apparatus for synchronous current regulation of a five-phase machine
Gallegos-Lopez, Gabriel; Perisic, Milun
2012-10-09
Methods, systems and apparatus are provided for controlling operation of and regulating current provided to a five-phase machine when one or more phases has experienced a fault or has failed. In one implementation, the disclosed embodiments can be used to synchronously regulate current in a vector controlled motor drive system that includes a five-phase AC machine, a five-phase inverter module coupled to the five-phase AC machine, and a synchronous current regulator.
Directory of Open Access Journals (Sweden)
Abdelkrim Sellam
2012-12-01
Full Text Available The polyphase [1] machines are developed mainly in the field of variable speed drives of high power because increasing the number of phases on the one hand allows to reduce the dimensions of the components in power modulators energy and secondly to improve the operating safety. By a vector approach (vector space, it is possible to find a set of single-phase machine and / or two-phase fictitious equivalent to polyphase synchronous machine.These fictitious machines are coupled electrically and mechanically but decoupled magnetically. This approach leads to introduce the concept of the equivalent machine (multimachine multiconverter system MMS which aims to analyze systems composed of multiple machines (or multiple converters in electric drives. A first classification multimachine multiconverter system follows naturally from MMS formalism. We present an example of a synchronous machine pent phase.
Self-commissioning of permanent magnet synchronous machine drives using hybrid approach
DEFF Research Database (Denmark)
Basar, M. Sertug; Bech, Michael Møller; Andersen, Torben Ole
2014-01-01
Self-commissioning of permanent-magnet (PM) synchronous machines (PMSMs) is of prime importance in an industrial drive system because control performance and system stability depend heavily on the accurate machine parameter information. This article focuses on a combination of offline and online ...
Gündoğdu, Tayfun; Kömürgöz, Güven
2012-08-01
Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality. The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted.
Simulating the effect of SFCL on limiting the internal fault of synchronous machine
Energy Technology Data Exchange (ETDEWEB)
Kheirizad, I [Islamic Republic of Iran Broadcasting, Tehran (Iran, Islamic Republic of); Varahram, M H [Ministry of Science, Research and Technology, Tehran (Iran, Islamic Republic of); Jahed-Motlagh, M R [Azad University of Science and Research, Tehran (Iran, Islamic Republic of); Rahnema, M; Mohammadi, A [Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)], E-mail: hadi_varahram@yahoo.com
2008-02-01
In this paper, we have modelled a synchronous generator with internal one phase to ground fault and then the performance of this machine with internal one phase to ground fault have been analyzed. The results show that if the faults occur in vicinity of machine's terminal, then we would have serious damages. To protect the machine from this kind of faults we have suggested integrating a SFCL (superconducting fault current limiter) into the machine's model. The results show that the fault currents in this case will reduce considerably without influencing the normal operation of the machine.
Energy Technology Data Exchange (ETDEWEB)
Saint-Michel, J. [Moteurs Leroy Somer, 16 - Angouleme (France)
2001-02-01
This article treats of the poly-phase coiling of AC rotating machines. For simplification reasons, the study has been limited to tri-phase coils, but the theoretical calculations can be extended to any other number of phases. The coils described are those encountered in the stators of synchronous and asynchronous machines and in the rotors of asynchronous machines with rings. The qualitative, quantitative and practical aspects are presented successively: 1 - magnetic field produced by a coil (single turn, distributed coil, coil schemes, multi-polarity coils); 2 - field generated by a tri-phase coil (rotating field theorem, qualitative influence of space harmonics); 3 - quantitative analysis of coil properties (magneto-motive force generated by coils, harmonic decomposition of the magneto-motive force wave, global coiling coefficients); 4 - comparative study of different regular coils (diametrical step, shortened step, distributed); 5 - irregular coils; 6 - other double polarity coils (Dahlander coupling, other multiple polarity possibilities); 7 - reduction of teething harmonics (determination of optimal twisting, influence of inclination on the dimensioning of machines); 8 - practical realization of coils (insulation, insertion inside the machine). (J.S.)
Fan, Yuchao; Hautier, J.
1994-01-01
Cet article présente des marches dégradées optimisées applicables à un ensemble convertisseur-machine synchrone, lorsque des défauts de conduction apparaissent au niveau du convertisseur. Après analyse de l'influence d'un défaut de commande sur les caractéristiques de l'ensemble d'entraînement, une stratégie de rattrapage, en marche dégradée monophasée, est d'abord proposée pour pallier aux inconvénients de deux types de défauts lorsque le neutre de la machine est isolé. Dans ce mode de march...
Obeid, Ziad
2012-01-01
Ce travail de thèse traite de la détection des défauts mécaniques des roulements à billes par analyse de grandeurs mécaniques et électriques dans des machines synchrones à aimants permanents haute vitesse. Le domaine applicatif de ce travail concerne l'aéronautique. Généralement, pour surveiller l'état des roulements à billes dans un actionneur électrique, des mesures vibratoires sont réalisées. Elles permettent, en exploitant le spectre du signal vibratoire, de mettre facilement en évidence ...
Design and Modeling of High Performance Permanent Magnet Synchronous Machines
Van der Geest, M.
2015-01-01
The electrification of transportation, and especially aerospace transportation, increases the demand for high performance electrical machines. Those machines often need to be fault-tolerant, cheap, highly efficient, light and small, and interface well with the inverter. In addition, the development
Contrôle des circuits auxiliaires des P.F.W. (arret machine 2004/2006)
Ottaviani, J
2005-01-01
Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d’aimant et constituées d’un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et “pick-up” brasés sur les enroulements principaux). Pendant la variation du champ magnétique de l’aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l’arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre “pick-up” et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, ...
Contrôle des Circuits Auxiliaires des P.F.W. (arrêt machine 2003/2004)
Ottaviani, J
2004-01-01
Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d'aimant et constituées d'un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et des circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et "pick-up" brasés sur les enroulements principaux). Pendant la variation du champ magnétique del'aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l'arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures de résistances des boucles de tours, résistances entre "pick-up" et isolation des circuits) afin de faire un suivi. Les 404 PFW sont ainsi vérifiées. Dans cette note, on ne relèvera que les PFW ayant des défauts (valeurs hors tolérances, boucles ouvertes ...
Topology Optimization of a High-Temperature Superconducting Field Winding of a Synchronous Machine
DEFF Research Database (Denmark)
Pozzi, Matias; Mijatovic, Nenad; Jensen, Bogi Bech
2013-01-01
genetic algorithm with local optimization search based on on/off sensitivity analysis. The results show an optimal HTS coil distribution, achieving compact designs with a maximum of approximately 22% of the available space for the field winding occupied with HTS tape. In addition, this paper describes......This paper presents topology optimization (TO) of the high-temperature superconductor (HTS) field winding of an HTS synchronous machine. The TO problem is defined in order to find the minimum HTS material usage for a given HTS synchronous machine design. Optimization is performed using a modified...
Energy Technology Data Exchange (ETDEWEB)
Ge Zhengming [Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 300, Taiwan (China)]. E-mail: zmg@cc.nctu.edu.tw; Lee, Ching-I [Department of Mechanical Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 300, Taiwan (China)
2005-03-01
Chaos, control, anticontrol and synchronization of chaos for an autonomous rotational machine system with a hexagonal centrifugal governor and spring for which time-delay effect is considered are studied in the paper. By applying numerical results, phase diagram and power spectrum are presented to observe periodic and chaotic motions. Linear feedback control and adaptive control algorithm are used to control chaos effectively. Linear and nonlinear feedback synchronization and phase synchronization for the coupled systems are presented. Finally, anticontrol of chaos for this system is also studied.
Directory of Open Access Journals (Sweden)
Abdelkrim Sellam,Boubakeur Dehiba,Mohamed B. Benabdallah,Mohamed Abid,Nacéra Bachir Bouiadjra,Boubakeur Bensaid,Mustapha Djouhri
2012-12-01
Full Text Available The polyphase [1] machines are developed mainly inthe field of variable speed drives of high powerbecause increasing the number of phases on the onehand allows to reduce the dimensions of thecomponents in power modulators energy and secondlyto improve the operating safety. By a vector approach(vector space, it is possible to find a set of singlephasemachine and / or two-phase fictitious equivalentto polyphase synchronous machine.These fictitiousmachines are coupled electrically and mechanicallybut decoupled magnetically. This approach leads tointroduce the concept of the equivalent machine(multimachine multiconverter system MMS whichaims to analyze systems composed of mul tiplemachines (or multiple converters in electric drives. Afirst classification multimachine multiconvertersystem follows naturally from MMS formalism. Wepresent an example of a synchronous machine pent
Impact of Model Detail of Synchronous Machines on Real-time Transient Stability Assessment
DEFF Research Database (Denmark)
Weckesser, Johannes Tilman Gabriel; Jóhannsson, Hjörtur; Østergaard, Jacob
2013-01-01
to identify the transient stability mechanism, a simulation with a high-order model was used as reference. The Western System Coordinating Council System (WSCC) and the New England & New York system are considered and simulations of an unstable and a stable scenario are carried out, where the detail......In this paper, it is investigated how detailed the model of a synchronous machine needs to be in order to assess transient stability using a Single Machine Equivalent (SIME). The results will show how the stability mechanism and the stability assessment are affected by the model detail. In order...... of the machine models is varied. Analyses of the results suggest that a 4th-order model may be sufficient to represent synchronous machines in transient stability studies....
Energy-saving operation of a converter-fed synchronous machine
Energy Technology Data Exchange (ETDEWEB)
Schmidt, I.; Veszpremi, K. [Technical University of Budapest, Department of Electrical Machines and Drives, Budapest (Hungary)
1997-12-31
In the Converter-Fed Synchronous Machine (CFSM) there is no need for forced commutation the CL and CF converters operate with line commutation, the CM is commutated by the machine voltages. This drive is applied mainly for large power and high speed controlled drives. Considering the large power, the investigation of energy-saving operation is important. As in the DC and the induction motor drives the energy-saving operation is implemented by flux control. (orig.) 6 refs.
COMMANDE NON LINEAIRE SANS CAPTEUR DE LA MACHINE SYNCHRONE A AIMANTS PERMANENTS
Ezzat, Marwa
2011-01-01
The permanent magnet synchronous motor when compared to other electric machines, is very present in motion control industrial applications. This is mainly because of its compactness, low inertia, dynamics performances, robustness, power density and simplicity of operation with mechanical sensor. However, sensorless control of this machine is always a difficult problem because of the observability loss problem. The aim of this thesis is to propose control laws for mechanical sensorless permane...
Script Controlled Modeling of Low Noise Permanent Magnet Synchronous Machines by using JMAG Designer
RUSU Tiberiu; BÎRTE Ovidiu; SZABÓ Loránd; MARŢIŞ Claudia Steluţa
2013-01-01
This paper deals with the parameterizedmodeling of permanent magnet synchronous machines(PMSM) by means of JMAG Designer, an advancedsimulation software for electromechanical design. Thismethod enables the designer to simulate diverse topologies ofthe machines by only changing some basic parameters of thescript controlling the preprocessing phase of the simulations.For this purpose a graphical user interface for modeling themachine was built up in Visual Basic. Thru it the users canenter the ...
Commande optimale à flux libre des machines asynchrones
Biedinger, J. M.; Poullain, S.; Yvon, J. P.
1992-01-01
The subject of this paper is the optimal control with unconstrained flux of an induction motor being considered as a distributed parameter system described by a nonlinear diffusion equation. This approach allows to describe the electrodynamic state of the motor by taking into account, in a natural way, the influence of saturation and eddy-currents, as well as the nonlinearities due to the variable flux operation. Equations are approximated via a finite element formulation which leads to a finite dimensional dynamical system to which the techniques of optimal control may be applied. The generality of the methodology allows to treat various criteria. The objective aimed in this paper is to force the motor torque to follow a given input, especially under initially demagnetized conditions and with, naturally, constraints on the currents. For this purpose the criterion will be chosen as a norm of the difference between the electromagnetic torque and a given reference torque. Numerical simulations are presented for the case of a squirrel-cage rotor and for a solid iron rotor. Results are compared with those deduced from strategies based on lumped-parameter models. Torque responses obtained with field-oriented control method adapted to the case of flux-variable operation are also presented. Finally a modification of the criterion is proposed for identifying the command which allows to obtain the larger torque during transient states. Dans cet article on traite le problème du contrôle optimal à flux libre d'un moteur asynchrone considéré comme un système à paramètres répartis gouverné par une équation de diffusion non linéaire. Cette approche permet de décrire l'état électrodynamique de la machine en prenant naturellement en compte les effets de la saturation et des courants induits, ainsi que les non-linéarités liées au fonctionnement à flux variable. La formulation éléments finis est utilisée pour traduire le problème continu sous la forme d
Influence of Voltage Dips on the Operation of Brushless Exciter System of Synchronous Machines
Fedotov, A.; Leonov, A.; Vagapov, G.; Mutule, A.
2016-06-01
This paper presents a mathematical model with continuous variables for brushless exciter system of synchronous machines, containing the thyristor elements. Discrete Laplace transform is used for transition from a mathematical model of a system with variable structure in continuous variables to equation finite difference with permanent structure. Then inverse transition is made to a mathematical model in continuous variables with permanent structure.
A Virtual Inertia Control Strategy for DC Microgrids Analogized with Virtual Synchronous Machines
DEFF Research Database (Denmark)
Wu, Wenhua; Chen, Yandong; Luo, An;
2017-01-01
synchronous machine (VSM) is proposed to enhance the inertia of the DC-MG, and to restrain the dc bus voltage fluctuation. The small-signal model of the BGC system is established, and the small-signal transfer function between the dc bus voltage and the dc output current of the BGC is deduced. The dynamic...
Prediction of chaos in non-salient permanent-magnet synchronous machines
Rasoolzadeh, Arsalan; Tavazoei, Mohammad Saleh
2012-12-01
This Letter tries to find the area in parameter space of a non-salient Permanent-Magnet Synchronous Machine (PMSM) in which chaos can occur. This area is briefly named as chaotic area. The predicted chaotic area is obtained by checking some conditions which are necessary for existence of chaos in a dynamical system. In this Letter, it is assumed that this machine is in the generator mode, and its model is based on direct and quadrature axis of stator voltages and currents. The information of the predicted area is used in non-chaotic maximum power control of torque in the machine.
Fan, Yuchao; Hautier, J. P.
1994-01-01
This paper presents the remedial strategies for a converter-synchronous machine system, which would be used in case of conduction faults in the converter. After an analysis of the influence of transistor drive faults, in the conversion system characteristics, a remedial strategy in single-phase operation is proposed to palliate the consequences of the transistor faults when the neutral point of synchronous machine is not connected. Developed torque in this operating mode is pulsating. To eliminate this inconvenient which disturbs the speed regulation, an optimized remedial strategy in two-phase operation is then proposed. The power part is modified and the neutral point of synthronous machine is connected to DC voltage. Simulation and experimentation validate the proposed strategies. Cet article présente des marches dégradées optimisées applicables à un ensemble convertisseur-machine synchrone, lorsque des défauts de conduction apparaissent au niveau du convertisseur. Après analyse de l'influence d'un défaut de commande sur les caractéristiques de l'ensemble d'entraînement, une stratégie de rattrapage, en marche dégradée monophasée, est d'abord proposée pour pallier aux inconvénients de deux types de défauts lorsque le neutre de la machine est isolé. Dans ce mode de marche, le couple développé par la machine synchrone est pulsatoire. Afin d'éviter cet inconvénient, nous proposons, ensuite, une marche dégradée en mode biphasé par modification de la structure de puissance, en reliant le neutre de la machine au point milieu d'alimentation. Enfin, les stratégies de commande proposées sont validées par la simulation et l'expérience.
Designing Of Permanent Magnet Synchronous Machine For Applications In Small Hydro Power Plants
Directory of Open Access Journals (Sweden)
Jayashree Sharma
2015-07-01
Full Text Available The need of the hour, as we all genuinely know from the global scenario is the production of electricity from the renewable resources of energy. Most widely used among them are the solar and the wind potential. Besides these, the hydroelectric resources also play a remarkable role as hydroelectricity accounts for a major share in the energy sector throughout the world. The trend at present is of the stand alone hydro power plants wherein the turbine used is the Hydrokinetic turbine , which works with the speed of flow of the water stream. Permanent magnet synchronous machines, known for their robust nature, variable speed, and high power to weight ratio are the most suitable ones for the construction of the turbine for low speed operation. This paper presents the design of permanent magnet synchronous machine and the machine has been modeled and simulated in RMXprt and Ansys Maxwell.
Effects of pole flux distribution in a homopolar linear synchronous machine
Balchin, M. J.; Eastham, J. F.; Coles, P. C.
1994-05-01
Linear forms of synchronous electrical machine are at present being considered as the propulsion means in high-speed, magnetically levitated (Maglev) ground transportation systems. A homopolar form of machine is considered in which the primary member, which carries both ac and dc windings, is supported on the vehicle. Test results and theoretical predictions are presented for a design of machine intended for driving a 100 passenger vehicle at a top speed of 400 km/h. The layout of the dc magnetic circuit is examined to locate the best position for the dc winding from the point of view of minimum core weight. Measurements of flux build-up under the machine at different operating speeds are given for two types of secondary pole: solid and laminated. The solid pole results, which are confirmed theoretically, show that this form of construction is impractical for high-speed drives. Measured motoring characteristics are presented for a short length of machine which simulates conditions at the leading and trailing ends of the full-sized machine. Combination of the results with those from a cylindrical version of the machine make it possible to infer the performance of the full-sized traction machine. This gives 0.8 pf and 0.9 efficiency at 300 km/h, which is much better than the reported performance of a comparable linear induction motor (0.52 pf and 0.82 efficiency). It is therefore concluded that in any projected high-speed Maglev systems, a linear synchronous machine should be the first choice as the propulsion means.
Multiphysics Modeling of an Permanent Magnet Synchronous Machine
Directory of Open Access Journals (Sweden)
MARTIS Claudia
2012-10-01
Full Text Available This paper analyzes the noise and vibration in PMSMs. There are three types of vibrations in electrical machines: electromagnetic,mechanical and aerodynamic. Electromagnetic force are the main cause of noise and vibration in PMSMs. It is very important to calculate precisely the natural frequencies of the stator system. If oneradial force (which are the main cause for electromagnetic vibration has the frequency close to the natural frequency of the stator system for the same order of vibrational mode, then this force canproduce dangerous vibration in the stator system. The natural frequencies for a stator system of a PMSM have been calculated. Finally a Structural Analysis has been made , pointing out the radialdisplacement and stress for the chosen PMSM .
DEFF Research Database (Denmark)
Zhang, Xiaoxu; Liu, Xiao; Liu, Jinglin;
2015-01-01
Flux-modulated permanent-magnet synchronous machine (FM-PMSM) is characterized as a high-torque direct-drive electrical machine, but may suffer from the low power factor. This paper aims to investigate the issue of the low power factor in theory and explore the possibilities for improvement....... An analytical model for the FM-PMSM is developed to obtain the magnetic field distribution, and its accuracy is verified by the finite-element method. On the basis of the developed analytical model, a fast approach is developed to predict the power factor of the FM-PMSM. The analytical results indicate...
Identification and non-integer order modelling of synchronous machines operating as generator
Directory of Open Access Journals (Sweden)
Szymon Racewicz
2012-09-01
Full Text Available This paper presents an original mathematical model of a synchronous generator using derivatives of fractional order. In contrast to classical models composed of a large number of R-L ladders, it comprises half-order impedances, which enable the accurate description of the electromagnetic induction phenomena in a wide frequency range, while minimizing the order and number of model parameters. The proposed model takes into account the skin eff ect in damper cage bars, the eff ects of eddy currents in rotor solid parts, and the saturation of the machine magnetic circuit. The half-order transfer functions used for modelling these phenomena were verifi ed by simulation of ferromagnetic sheet impedance using the fi nite elements method. The analysed machine’s parameters were identified on the basis of SSFR (StandStill Frequency Response characteristics measured on a gradually magnetised synchronous machine.
Liang, Wenyi
2017-01-01
The rising public awareness of climate change and urban air pollution has been one of the key drivers for transport electrification. Such trend drastically accelerates the quest for high-power-and-torque-density electric drive systems. The rare-earth permanent magnet synchronous machine, with its excellent steady-state and dynamic characteristics, has been the ideal candidate for these applications. Specifically, the fractional-slot and concentrated-winding configuration is wid...
Influence of Voltage Dips on the Operation of Brushless Exciter System of Synchronous Machines
Directory of Open Access Journals (Sweden)
Fedotov A.
2016-06-01
Full Text Available This paper presents a mathematical model with continuous variables for brushless exciter system of synchronous machines, containing the thyristor elements. Discrete Laplace transform is used for transition from a mathematical model of a system with variable structure in continuous variables to equation finite difference with permanent structure. Then inverse transition is made to a mathematical model in continuous variables with permanent structure.
Application des aimants aux machines électriques
2010-01-01
1- Historique, introduction2- Modélisation d’un aimant2.1- Aimants « rigides » (ou durs)2.2- Aimant dur dans un circuit magnétique. Point de fonctionnement2.3- Aimants « peu rigides »2.4- Formulation de l’énergie interne des aimants rigides3- Caractéristiques des différentes technologies3.1- Caractéristiques générales des aimants permanents actuels3.2- Causes de désaimantation irréversible et vieillissement3.3- Exemples de courbes de caractéristiques B(H) de différentes technologies d’aimants...
A Novel Cogging Torque Simulation Method for Permanent-Magnet Synchronous Machines
Directory of Open Access Journals (Sweden)
Chun-Yu Hsiao
2011-12-01
Full Text Available Cogging torque exists between rotor mounted permanent magnets and stator teeth due to magnetic attraction and this is an undesired phenomenon which produces output ripple, vibration and noise in machines. The purpose of this paper is to study the existence and effects of cogging torque, and to present a novel, rapid, half magnet pole pair technique for forecasting and evaluating cogging torque. The technique uses the finite element method as well as Matlab research and development oriented software tools to reduce numerous computing jobs and simulation time. An example of a rotor-skewed structure used to reduce cogging torque of permanent magnet synchronous machines is evaluated and compared with a conventional analysis method for the same motor to verify the effectiveness of the proposed approach. The novel method is proved valuable and suitable for large-capacity machine design.
Self-commissioning of permanent magnet synchronous machine drives using hybrid approach
DEFF Research Database (Denmark)
Basar, Mehmet Sertug
2014-01-01
Self-commissioning of permanent-magnet (PM) synchronous machines (PMSMs) is of prime importance in an industrial drive system because control performance and system stability depend heavily on the accurate machine parameter information. This article focuses on a combination of offline and online...... parameter estimation for a non-salient pole PMSM which eliminates the need for any prior knowledge on machine parameters. Stator resistance and inductance are first identified at standstill utilising fundamental and high-frequency excitation signals, respectively. A novel method has been developed...... and employed for inductance estimation. Then, stator resistance, inductance and PM flux are updated online using a recursive least-squares (RLS) algorithm. The proposed controllers are designed using MATLAB/Simulink® and implemented on d-Space® real-time system incorporating a commercially available PMSM drive....
Co-Simulation of an Inverter Fed Permanent Magnet Synchronous Machine
Directory of Open Access Journals (Sweden)
Kiss Gergely Máté
2014-10-01
Full Text Available Co-simulation is a method which makes it possible to study the electric machine and its drive at once, as one system. By taking into account the actual inverter voltage waveforms in a finite element model instead of using only the fundamental, we are able to study the electrical machine's behavior in more realistic scenario. The recent increase in the use of variable speed drives justifies the research on such simulation techniques. In this paper we present the co-simulation of an inverter fed permanent magnet synchronous machine. The modelling method employs an analytical variable speed drive model and a finite element electrical machine model. By linking the analytical variable speed drive model together with a finite element model the complex simulation model enables the investigation of the electrical machine during actual operation. The methods are coupled via the results. This means that output of the finite element model serves as an input to the analytical model, and the output of the analytical model provides the input of the finite element model for a different simulation, thus enabling the finite element simulation of an inverter fed machine. The resulting speed and torque characteristics from the analytical model and the finite element model show a good agreement. The experiences with the co-simulation technique encourage further research and effort to improve the method.
Energy Technology Data Exchange (ETDEWEB)
Sadowski, Nelson; Bastos, J.P. Assumpcao; Carlson, R. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Eletrica; Lajoie-Mazenc, M. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France). Lab. d`Eletrotechnique et d`Eletronique Industrielle
1995-12-31
The finite elements method is used in the analysis of electric machines giving special emphasis to the synchronous machine. The developed computational method enables the obtention of global information such as torch, electromotive force, inductance, among others. The methodology is presented 6 figs., 7 refs.
DEFF Research Database (Denmark)
Chen, Zhe; Blaabjerg, Frede; Iov, Florin
2005-01-01
A direct phase model of synchronous machines implemented in MA TLAB/SIMULINK is presented. The effects of the machine saturation have been included. Simulation studies are performed under various conditions. It has been demonstrated that the MATLAB/SIMULINK is an effective tool to study the complex...
DEFF Research Database (Denmark)
Chen, Zhe; Blaabjerg, Frede; Iov, Florin
2005-01-01
A direct phase model of synchronous machines implemented in MA TLAB/SIMULINK is presented. The effects of the machine saturation have been included. Simulation studies are performed under various conditions. It has been demonstrated that the MATLAB/SIMULINK is an effective tool to study the complex...
Institute of Scientific and Technical Information of China (English)
Qi-huai CHEN; Qing-feng WANG; Tao WANG
2015-01-01
A hybrid power transmission system (HPTS) is a promising way to save energy in a hydraulic excavator and the electric machine is one of the key components of the system. In this paper, a design process for permanent-magnet synchronous machines (PMSMs) in a hybrid hydraulic excavator (HHE) is presented based on the analysis of the working conditions and requirements of an HHE. A parameterized design approach, which combines the analytical model and the 2D finite element method (FEM), is applied to the electric machine to improve the design efficiency and accuracy. The analytical model is employed to optimize the electric machine efficiency and obtain the stator dimension and flux density distribution. The rotor is designed with the FEM to satisfy the flux requirements obtained in stator design. The rotor configuration of the PMSM employs an interior magnet structure, thus resulting in some inverse saliency, which allows for much higher values in magnetic flux density. To reduce the rotor leakage, a disconnected type silicon steel block structure is adopted. To improve the air gap flux density distribution, the trapezoid permanent magnet (PM) and centrifugal rotor structure are applied to PMSM. Demagnetization and armature reactions are also taken into consideration and calculated by the FEM. A prototype of the newly designed electric machine has been fabri-cated and tested on the experimental platform. The analytical design results are validated by measurements.
DEFF Research Database (Denmark)
Wu, Qian; Lu, Kaiyuan; Rasmussen, Peter Omand
2016-01-01
This paper introduces a new application of moulding technology to the installation of ferrite magnet material into the rotor flux barriers of Ferrite Magnet Assisted Synchronous Reluctance Machine (FASynRM). The feasibility of this application with respect to manufacturing process and motor...... performance has been demonstrated. In comparison to the conventional ferrite magnet installation approach, moulding technology has obvious advantages of improved mechanical strength of the multi-flux-barrier rotor structure, simplified installation process, reduced processing cost and in the same time...
Contribution à la compensation active des vibrations des machines électriques
Granjon, Pierre
2000-01-01
This work is devoted to elaborate an active control system of rotating machine vibrations. It is based on additional currents supplying the stator coils of the machine. They generate radial forces on the stator frame,and finally create additional vibrations which interact with the machine ones. Therefore, the aim of this system is to process the optimal value of the input currents, in order to minimize the vibration signals power measured on the stator frame by several accelerometers.First, t...
Kim, Seok-Kyoon; Song, Hwachang; Yoon, Tae-Woong
2015-04-01
On the basis of the non-linear third-order generator model, this article proposes a dual control scheme for a single synchronous machine equipped with an energy storage device to regulate the terminal voltage while enhancing the damping. Based on the input-output feedback linearisation method, the exciter controller is designed such that the terminal voltage robustly converges to its predetermined reference in the presence of a model uncertainty. In addition, the control input of the energy storage device feedbacks only the relative speed. It is shown that this controller can effectively increase the damping of the synchronous machine and that there is a set of initial conditions such that all trajectories started from this set go to the equilibrium point, satisfying input constraints. Moreover, it is also verified that all generator variables are bounded except for the power angle. The simulation results show that the closed-loop performance is satisfactory despite a transmission line fault and a model uncertainty in which the non-linear fourth-order generator model (two-axis) is used.
Ottaviani, J
2006-01-01
Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d'aimant et constituées d'un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (boucles de tour et ?pick-up? brasés sur les enroulements principaux). Pendant la variation du champ magnétique de l'aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Chaque année, pendant l'arrêt machine, on vérifie si les caractéristiques des circuits auxiliaires correspondent aux normes (mesures des résistances des boucles de tours, résistances entre ?pick-up? et isolation des circuits) afin de faire un suivi. Des mesures ont été faites au début du grand arrêt en décembre 2004 afin de définir quels aimants seraient à rénover (l'état des PFW e...
Directory of Open Access Journals (Sweden)
CAMPEANU, A.
2012-02-01
Full Text Available In the paper is shown that, by using the circuit theory which operates with lumped parameters, it is possible to derive mathematical models of a high power salient pole synchronous machine (SPSM, that can take into account the basic processes of the machine. It offers results regarding the electromagnetic and mechanical stresses for a given practical application. The quantitative determinations were performed on an 8000 kW synchronous motor. The results of quantitative determinations are of essential interest in the designing stage, for dynamic characteristics and parameters derivation and for constructive solutions to be chosen.
Design, analysis and fabrication of a linear permanent magnet synchronous machine
Indian Academy of Sciences (India)
MONOJIT SEAL; MAINAK SENGUPTA
2017-08-01
This paper deals with the design, analysis and fabrication of a 320 W, 5 m/s, 4-pole permanentmagnet-based linear synchronous machine (LPMSM). The design deals with conventional hand calculations followed by design fine-tuning and analysis using standard FEM packages. Fabrication of the machine has beenalso done at the works of a local small machine manufacturer after procurement of imported permanent magnets (PMs). The work presented here focuses on design and fabrication of LPMSM linor stampings with fixed dimensions and standard available PM tablets with a view to providing simple design guidelines. This prototype forms part of a variable speed linear motor drive that is being developed. The approach presented here might provide new ideas to those researchers who may not have the capability to bear cost of fabrication of lamination and PMs from scratch but would like to manufacture LPMSMs from available stampings and tablet PMs.Additionally, it may serve as a base document for the R&D personnel in this area.
Institute of Scientific and Technical Information of China (English)
Cheng-zhi FAN; Ming-xing HUANG; Yun-yue YE
2009-01-01
We propose a novel kind of compound permanent magnet synchronous machine (CPMSM), which is applicable in low-speed and high-torque situations. We first explain the structure of the CPMSM. Based on theoretically deducing the calculation formulae of the CPMSM electromagnetic parameters, we analyze the operating characteristics of the CPMSM, and obtain the power-angle curves and working curves. The no-load magnetic field distribution and the cogging torque are analyzed by applying the finite element method of three-dimensional (3D) magnetic fields, to determine the no-load leakage coefficient and the wave0form of the cogging torque. Furthermore, the optimal parameters of the permanent magnet for reducing the cogging torque are determined. An important application target of the CPMSM is in direct-drive pumping units. We have installed and tested a directdrive pumping unit in an existing oil well. Test results show that the power consumption of the direct-drive pumping unit driven by CPMSM is 6 1. 1% of that of the beam-pumping unit, and that the floor space and weight are only 50% of those of a beam-pumping unit. The noise output does not exceed 58 dB in a range of 1 m around the machine when the machine is 1.5 m from the ground.
Etude tribologique sur des lubrifiants solides à haute température dans des machines de détente
Legros, Arnaud; Zaïdi, Hamid; Diny, Mouad; Diaby, Moussa; Lemort, Vincent
2013-01-01
Dans le cadre de la conception d’un expanseur dédié à la récupération d’énergie à l’échappement d’un moteur à combustion interne, une étude sur des lubrifiants solides a été menée afin de choisir le couple de matériaux adéquat pour le joint principal de la machine. Ce joint doit assurer à la fois une fonction d’étanchéité interne et limiter ainsi les pertes par fuites internes de l’expanseur. Il doit également présenter un coefficient de frottement la plus faible possible afin de réduire les ...
Directory of Open Access Journals (Sweden)
A.M. Galynovskiy
2013-10-01
Full Text Available Designing features for valve-engine transducers of brushless synchronous and asynchronized machines are described. Global analysis of research results on the transducer models in a MicroCap circuit simulation system is made, recommendations on the simulation system application in both scientific research and educational process given.
DEFF Research Database (Denmark)
Lu, Kaiyuan; Vetuschi, M.; Rasmussen, Peter Omand;
2010-01-01
This paper presents a reliable method for the experimental determination of high-frequency d- and q -axis inductances for surface-mounted permanent-magnet synchronous machines (SMPMSMs). Knowledge of the high-frequency d- and q-axis inductances plays an important role in the efficient design...
Institute of Scientific and Technical Information of China (English)
CHEN Yiguang; PAN Wei; SHEN Yonghuan; TANG Renyuan
2006-01-01
Conventional permanent magnet synchronous machine(PMSM)has the problem of large stator copper loss and narrow speed range. To solve this problem, an interior composite-rotor controllable-flux PMSM adaptive to multi-polar is proposed. This machine has the characteristics of low stator copper loss and wide-speed operation. The half-radial-set and half-tangential-set permanent magnets(PMs)are NdFeB that has high remanent flux density and high coercive force. The tangential-set PMs are AlNiCo that has high remanent flux density and low coercive force. By applying the pulse of d-axis stator current id, the magnetized intensity and direction of AlNiCo can be controlled. The flux created by NdFeB is repelled to stator and air-gap PM-flux is intensified, or is partially bypassed by AlNiCo in the rotor, so the air-gap PM-flux is weakened. The internal magnetic field distribution in two ultra magnetized situations is analyzed by finite element method. The dimension of PMs and magnetic structure are demonstrated. Especially when the q-axis magnetic resistance is larger and the q-axis inductance is smaller, the result of flux-weakening is better and the influence of armature reaction on air-gap PM-flux is weakened.
Energy Technology Data Exchange (ETDEWEB)
Elizondo, Marcelo A.; Tuffner, Francis K.; Schneider, Kevin P.
2016-01-01
Unlike transmission systems, distribution feeders in North America operate under unbalanced conditions at all times, and generally have a single strong voltage source. When a distribution feeder is connected to a strong substation source, the system is dynamically very stable, even for large transients. However if a distribution feeder, or part of the feeder, is separated from the substation and begins to operate as an islanded microgrid, transient dynamics become more of an issue. To assess the impact of transient dynamics at the distribution level, it is not appropriate to use traditional transmission solvers, which generally assume transposed lines and balanced loads. Full electromagnetic solvers capture a high level of detail, but it is difficult to model large systems because of the required detail. This paper proposes an electromechanical transient model of synchronous machine for distribution-level modeling and microgrids. This approach includes not only the machine model, but also its interface with an unbalanced network solver, and a powerflow method to solve unbalanced conditions without a strong reference bus. The presented method is validated against a full electromagnetic transient simulation.
Investigation of fault modes in permanent magnet synchronous machines for traction applications
Choi, Gilsu
Over the past few decades, electric motor drives have been more widely adopted to power the transportation sector to reduce our dependence on foreign oil and carbon emissions. Permanent magnet synchronous machines (PMSMs) are popular in many applications in the aerospace and automotive industries that require high power density and high efficiency. However, the presence of magnets that cannot be turned off in the event of a fault has always been an issue that hinders adoption of PMSMs in these demanding applications. This work investigates the design and analysis of PMSMs for automotive traction applications with particular emphasis on fault-mode operation caused by faults appearing at the terminals of the machine. New models and analytical techniques are introduced for evaluating the steady-state and dynamic response of PMSM drives to various fault conditions. Attention is focused on modeling the PMSM drive including nonlinear magnetic behavior under several different fault conditions, evaluating the risks of irreversible demagnetization caused by the large fault currents, as well as developing fault mitigation techniques in terms of both the fault currents and demagnetization risks. Of the major classes of machine terminal faults that can occur in PMSMs, short-circuit (SC) faults produce much more dangerous fault currents than open-circuit faults. The impact of different PMSM topologies and parameters on their responses to symmetrical and asymmetrical short-circuit (SSC & ASC) faults has been investigated. A detailed investigation on both the SSC and ASC faults is presented including both closed-form and numerical analysis. The demagnetization characteristics caused by high fault-mode stator currents (i.e., armature reaction) for different types of PMSMs are investigated. A thorough analysis and comparison of the relative demagnetization vulnerability for different types of PMSMs is presented. This analysis includes design guidelines and recommendations for
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Liu Xiping
2017-06-01
Full Text Available This paper proposes a permanent magnet (PM-assisted synchronous reluctance machine (PMASynRM using ferrite magnets with the same power density as rareearth PM synchronous motors employed in Toyota Prius 2010. A suitable rotor structure for high torque density and high power density is discussed with respect to the demagnetization of ferrite magnets, mechanical strength and torque ripple. Some electromagnetic characteristics including torque, output power, loss and efficiency are calculated by 2-D finite element analysis (FEA. The analysis results show that a high power density and high efficiency of PMASynRM are obtained by using ferrite magnets.
Modélisation des défauts de bobinage de la machine asynchrone pour son diagnostic
Schaeffer, Emmanuel; Bachir, Smail
2011-01-01
International audience; La surveillance et le diagnostic des machines électriques représentent un enjeu scientifique et économique motivé par les objectifs de sûreté de fonctionnement et de continuité de service des entraînements électriques. Les défauts susceptibles de se produire sur ces dispositifs sont d'origines diverses : court-circuit d'enroulement, rupture de barre de rotor à cage d'écureuil, défaut de roulement, échauffement anormal de la machine, défaut de composant de l'onduleur, m...
Energy Technology Data Exchange (ETDEWEB)
Sartre, V.; Lallemand, M. (Centre National de la Recherche Scientifique, 69 - Villleurbanne (France)); Chiaffi, M. (Societe Bertin et Compagnie, 78 - Plaisir (France))
1994-03-01
The present study is related to the development of compressors for heat pumps and refrigerating machines. For a given application, various compressor technologies are possible. The choice is often dictated by the experience acquired on a compressor type, ensuring good reliability and a reasonable cost of the plant. In our study, we examine the limits of various compressor types: piston, screw, scroll, rotary vane, rolling piston and centrifugal. A comparison of the theoretical and practical limits of the compressors' operating ranges shows the necessity of better adaptation of the compressor type to each application. Finally, we suggest the main research focus for the development of future compressors. The new technologies should evolve towards a variable-speed operation, without lubricating oil or with refrigerant lubrication. Acoustic comfort is also an important criterion. (author)
Pradel, M.; Pacaud, T.; Cariolle, M.
2011-01-01
/ Ce document est un rapport de synthèse des travaux réalisés dans le cadre du projet Ecodefi sur l'estimation des émissions azotées lors de l'épandage de boues issues du traitement des eaux usées en lien avec les performances technologiques des machines utilisées à cet effet.
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D. Ouamara
2016-09-01
Full Text Available Authors compare the electromagnetic performances of three multi-phases permanent-magnet (PM synchronous machines (PMSM for Mild Hybridtraction application. This comparison was made using two-dimensional (2-D numerical simulations in transient magnetic with eddy-current reaction field in the PMs. The best machine was determined using an energetic analysis (i.e., losses, torque and efficiency according specifications. In this study, the non-overlapping winding with double layer (i.e. all teeth wound type was used. The winding synthesis is based on the "Star of slots" method as well as the Fourier series decomposition of the magnetomotive force (MMF.
Boudana, Djamel; Nezli, Lazhari; Tlemçani, Abdelhalim; Mahmoudi, Mohand Oulhadj; Tadjine, Mohamed
2012-05-01
The double star synchronous machine (DSSM) is widely used for high power traction drives. It possesses several advantages over the conventional three phase machine. To reduce the torque ripple the DSSM are supplied with source voltage inverter (VSI). The model of the system DSSM-VSI is high order, multivariable and nonlinear. Further, big harmonic currents are generated. The aim of this paper is to develop a new direct torque adaptive fuzzy logic control in order to control DSSM and minimize the harmonics currents. Simulations results are given to show the effectiveness of our approach.
Picot, Antoine; Obeid, Ziad; Régnier, Jérémi; Poignant, Sylvain; Darnis, Olivier; Maussion, Pascal
2014-01-01
International audience; In this paper, an original method for bearing fault detection in high speed synchronous machines is presented. This method is based on the statistical process of Welch's periodogram of the stator currents in order to obtain stable and normalized fault indicators. The principle of the method is to statistically compare the current spectrum to a healthy reference so as to quantify the changes over the time. A statistic-based indicator is then constructed by monitoring sp...
Energy Technology Data Exchange (ETDEWEB)
Fusco, Miguel A.V.; Reis, Luiz O.M. dos [Universidade de Taubate (UNITAU), SP (Brazil)
2009-07-01
In the printing industry there is several segments and one of these segments is the printing in sheet metal, known how cans manufacturer (metallography). This segment consists in a preparation of the steel plates for the manufacturing industry for both cans household and industrial fields. Today most of the machines in this market segment is old and often driven by only one electric motor. The speed variation occurs through electromechanical and / or electromagnetic inverters or DC motors whose process timing and positioning of the sheet along the machine is via mechanical systems gears, gearboxes, belts and transmissions. The objective of this work is to suggest the replacement of the set of mechanical transmission by a completely electronic system through the use of AC motors, frequency inverters and programmable logic controller (PLC), that the synchronization system and position are done by encoders coupled to the PLC, ensuring the proper functioning of the whole machine. Using this system, the index of maintenance will be reduced and the machine speed will be increased from 5% to 10%, ensuring a higher production.
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Jeeng Min Ling
2016-08-01
Full Text Available The cogging torque in an inset permanent magnet synchronous machine causes some undesirable vibration and noises which should be reduced in the earliest possible stage of design. The influences of edge slotting and slot opening width in the magnet rotor pole on the cogging torque were investigated in this article. The structure of the proposed inset permanent magnet synchronous machine has 8 poles and 24 stator slots with fixed slot opening width and a modified magnet pole in the rotor. The finite element method magnetics (FEMM 4.2 tool was used to investigate the core saturation induced in the stator and rotor of the inset permanent magnet synchronous machine. The simulation results show that the slotting design in the magnet edge can effectively reduce the cogging torque of the inset permanent magnet synchronous machine.
Jeeng Min Ling; Tajuddin Nur
2016-01-01
The cogging torque in an inset permanent magnet synchronous machine causes some undesirable vibration and noises which should be reduced in the earliest possible stage of design. The influences of edge slotting and slot opening width in the magnet rotor pole on the cogging torque were investigated in this article. The structure of the proposed inset permanent magnet synchronous machine has 8 poles and 24 stator slots with fixed slot opening width and a modified magnet pole in the rotor. The f...
Rasilo, Paavo; Abdallh, Ahmed Abou-Elyazied; Belahcen, Anouar; Arkkio, Antero; Dupre, Luc
2015-01-01
The magnetic material characteristics of a wound-ﬁeld synchronous machine are identiﬁed based on global calorimetric core-loss and no-load curve measurements. This is accomplished by solving a coupled experimental-numerical electromagnetic inverse problem, formulated to minimize the difference between a ﬁnite-element (FE) simulation-based Kriging surrogate model and the measurement results. The core-loss estimation in the FE model is based on combining a dynamic iron-loss model and a static v...
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Zhiyi Song
2012-01-01
Full Text Available The compound-structure permanent-magnet synchronous machine (CS-PMSM, comprising a double rotor machine (DRM and a permanent-magnet (PM motor, is a promising electronic-continuously variable transmission (e-CVT concept for hybrid electric vehicles (HEVs. By CS-PMSM, independent speed and torque control of the vehicle engine is realized without a planetary gear unit. However, the slip rings and brushes of the conventional CS-PMSM are considered a major drawback for vehicle application. In this paper, a brushless flux-modulated CS-PMSM is investigated. The operating principle and basic working modes of the CS-PMSM are discussed. Mathematical models of the CS-PMSM system are given, and joint control of the two integrated machines is proposed. As one rotor of the DRM is mechanically connected with the rotor of the PM motor, special rotor position detection and torque allocation methods are required. Simulation is carried out by Matlab/Simulink, and the feasibility of the control system is proven. Considering the complexity of the controller, a single digital signal processor (DSP is used to perform the interconnected control of dual machines instead of two separate ones, and a typical hardware implementation is proposed.
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Kai-Hui Zhao
2017-06-01
Full Text Available To improve the accuracy of torque control for vector control of interior permanent-magnet synchronous machine (IPMSM, this study proposes a torque-sensorless control method based on cascaded sliding mode observer (SMO. First, the active flux model is discussed, which converts the model of IPMSM into the equivalent model of surface-mounted permanent-magnet synchronous machine. Second, to reduce chattering caused by system parameters variations and external disturbances, the cascaded observer is designed, which is composed of a variable gain adaptive SMO and an active flux SMO. The variable gain adaptive SMO is designed to estimate the speed, rotor position and stator resistance in the d–q reference frame. The active flux SMO is designed to estimate the active flux and torque in the α–β reference frame. Global asymptotic stability of the observers is guaranteed by the Lyapunov stability analysis. Finally, simulations and experiments are carried out to verify the effectiveness of the proposed control scheme.
A sensorless initial rotor position's estimation for permanent magnet synchronous machines
Krasnov, I.; Langraf, S.; Odnolopylov, I.; Koltun, V.
2015-10-01
Permanent magnet synchronous motors for the effective start require information about the initial position of a rotor. In this regard, most systems use position sensors, which substantially increase entirely a cost of an electrical drive [1-3]. The aim of this article is to develop a new method, allowing determining the absolute angular position of the permanent magnet synchronous motors’ rotor [4,5]. With a certain voltage pulses applied to the motor, its stator is magnetized by currents leakage in the windings. This allows using a special algorithm to calculate the absolute position of the rotor without using any motor parameters [6]. Simulation results prove the simplicity and efficiency of this method for determining an initial position of the permanent magnet synchronous motors’ rotor. Thus, this method can be widely used in the electrical industry.
380 kW synchronous machine with HTS rotor windings--development at Siemens and first test results
Nick, W.; Nerowski, G.; Neumüller, H.-W.; Frank, M.; van Hasselt, P.; Frauenhofer, J.; Steinmeyer, F.
2002-08-01
Applying HTS conductors in the rotor of synchronous machines allows the design of future motors or generators that are lighter, more compact and feature an improved coefficient of performance. To address these goals a project collaboration was installed within Siemens, including Automation & Drives, Large Drives as a leading supplier of electrical machines, Corporate Technology as a competence center for superconducting technology, and other partners. The main task of the project was to demonstrate the feasibility of basic concepts. The rotor was built from racetrack coils of Bi-2223 HTS tape conductor, these were assembled on a core and fixed by a bandage of glass-fibre composite. Rotor coil cooling is performed by thermal conduction, one end of the motor shaft is hollow to give access for the cooling system. Two cooling systems were designed and operated successfully: firstly an open circuit using cold gaseous helium from a storage vessel, but also a closed circuit system based on a cryogenerator. To take advantage of the increased rotor induction levels the stator winding was designed as an air gap winding. This was manufactured and fitted in a standard motor housing. After assembling of the whole system in a test facility with a DC machine load experiments have been started to prove the validity of our design, including operation with both cooling systems and driving the stator from the grid as well as by a power inverter.
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Jingang Bai
2014-03-01
Full Text Available The compound-structure permanent-magnet synchronous machine (CS-PMSM is a power-split device which can enable the internal combustion engine (ICE to operate at optimum efficiency during all driving conditions by controlling its torque and speed. However, the CS-PMSM has more serious temperature rise and heat dissipation problems than conventional permanent-magnet (PM machines, especially when the CS-PMSM is running at low speed and under full load conditions. As the thermal resistance of double-layer air gaps is quite big, the hot spot proves to be in the inner winding rotor. To ensure the safe operation of the CS-PMSM, the use of forced-air and water cooling in the inner winding rotor are investigated. The study shows that the water cooling can provide a better cooling effect, but require a complicated mechanical structure. Considering the complexity of the high efficiency cooling system, a real-time temperature monitoring method is proposed and a temperature measuring system which can accurately measure the real-time temperature of multiple key points in the machine is developed to promptly adjust the operating and cooling conditions based on the measured temperature results. Finally, the temperature rise experiment of the CS-PMSM prototype is done and the simulation results are partly validated by the experimental data.
Spargo, C.M.; Mecrow, B.C.; Widmer, J.D.
2014-01-01
A novel method to calculate the harmonic torque components in synchronous machines is presented. Harmonic torque components create a torque ripple, which is undesirable in many applications. This torque ripple is a major cause of acoustic noise and vibration and can limit the machine's application range. A seminumerical method is developed to calculate and analyze harmonic torque components based on Maxwell stress tensor theory. Development of the Maxwell stress expressions leads to a simple ...
Synchronized assembly of gold nanoparticles driven by a dynamic DNA-fueled molecular machine.
Song, Tingjie; Liang, Haojun
2012-07-04
A strategy for gold nanoparticle (AuNP) assembly driven by a dynamic DNA-fueled molecular machine is revealed here. In this machine, the aggregation of DNA-functionalized AuNPs is regulated by a series of toehold-mediated strand displacement reactions of DNA. The aggregation rate of the AuNPs can be regulated by controlling the amount of oligonucleotide catalyst. The versatility of the dynamic DNA-fueled molecular machine in the construction of two-component "OR" and "AND" logic gates has been demonstrated. This newly established strategy may find broad potential applications in terms of building up an "interface" that allows the combination of the strand displacement-based characteristic of DNA with the distinct assembly properties of inorganic nanoparticles, ultimately leading to the fabrication of a wide range of complex multicomponent devices and architectures.
FEM analysis of an single stator dual PM rotors axial synchronous machine
Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.
2017-01-01
The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors. The proposed topologies, the magneto-motive force analysis and quasi 3D-FEM analysis are the core of the paper.
Jiang, Ming
As an energy storage device, the flywheel has significant advantages over conventional chemical batteries, including higher energy density, higher efficiency, longer life time, and less pollution to the environment. An effective flywheel system can be attributed to its good motor/generator (M/G) design. This thesis describes the research work on the design of a permanent magnet synchronous machine (PMSM) as an M/G suitable for integration in a flywheel energy storage system within a large hybrid electric vehicle (HEV). The operating requirements of the application include wide power and speed ranges combined with high total system efficiency. Along with presenting the design, essential issues related to PMSM design including cogging torque, iron losses and total harmonic distortion (THD) are investigated. An iterative approach combining lumped parameter analysis with 2D Finite Element Analysis (FEA) was used, and the final design is presented showing excellent performance.
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Haipeng Wang
2012-09-01
Full Text Available This paper deals with a fault-tolerant semi-12-phase permanent-magnet synchronous machine (PMSM used for electric vehicles. High fault-tolerant and low toque ripple features are achieved by employing fractional slot concentrated windings (FSCWs and open windings. Excessive magnetomotive force (MMF harmonic components can lead to thermal demagnetization of rotor magnets as well as high core loss. An improved all-teeth-wound winding disposition that changes the winding factor of each harmonic is applied to suppress harmonics. A relatively large slot leakage inductance that limits the short-circuit current (SCC induced in the short-circuited winding is proposed to deal with short-circuit fault. Fault-tolerant controls up to two phases open circuited are investigated in this paper based on keeping the same torque-producing MMF. The fault-tolerant control strategies corresponding to each faulty mode are studied and compared to ensure high performance operation.
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Olfa B.H.B. Kechiche
2011-01-01
Full Text Available Problem statement: This study investigates a novel optimized scheme of a High Frequency Signal Injection (HFSI based sensorless technique in order to carry out a precise and robust rotor position error estimation of a Permanent Magnet Synchronous Motor (PMSM drive designed for washing machines. The study is carried out for standstill condition, where precise position information is required for this application. Approach: In order to get rotor position error information, a PMSM high frequency model is considered in the estimated rotor reference frame (d,q. Then, the impact of the HFSI technique parameters choice on the PMSM rotor position estimation performance is studied and experimentally tested, under various injection conditions. Results: The experimental results show that the amplitude of the high frequency current, resulting from injection, is not significant to carry out high performance rotor position estimation. In order to improve rotor position estimation performance and robustness, a modified demodulation of the high frequency current resulting from injection is proposed by using a high pass filter amplifier applied to PMSM measured currents. The novel proposed rotor position error extraction scheme is implemented on a dsPIC30F6010A and is experimentally validated on a 1kW washing salient pole PMSM. Conclusion: This study presents an improved high frequency voltage injection based sensorless control for Permanent Magnet Synchronous Motor (PMSM designed for washing machines. The optimal parameters choice of the HFSI technique and the use of a high pass filter amplifier have allowed to take the most of the high frequency injected signal for extracting the rotor position error at standstill, compared to a conventional scheme.
Sizov, Gennadi Y.
In this dissertation, a model-based multi-objective optimal design of permanent magnet ac machines, supplied by sine-wave current regulated drives, is developed and implemented. The design procedure uses an efficient electromagnetic finite element-based solver to accurately model nonlinear material properties and complex geometric shapes associated with magnetic circuit design. Application of an electromagnetic finite element-based solver allows for accurate computation of intricate performance parameters and characteristics. The first contribution of this dissertation is the development of a rapid computational method that allows accurate and efficient exploration of large multi-dimensional design spaces in search of optimum design(s). The computationally efficient finite element-based approach developed in this work provides a framework of tools that allow rapid analysis of synchronous electric machines operating under steady-state conditions. In the developed modeling approach, major steady-state performance parameters such as, winding flux linkages and voltages, average, cogging and ripple torques, stator core flux densities, core losses, efficiencies and saturated machine winding inductances, are calculated with minimum computational effort. In addition, the method includes means for rapid estimation of distributed stator forces and three-dimensional effects of stator and/or rotor skew on the performance of the machine. The second contribution of this dissertation is the development of the design synthesis and optimization method based on a differential evolution algorithm. The approach relies on the developed finite element-based modeling method for electromagnetic analysis and is able to tackle large-scale multi-objective design problems using modest computational resources. Overall, computational time savings of up to two orders of magnitude are achievable, when compared to current and prevalent state-of-the-art methods. These computational savings allow
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Fedotov A.
2017-02-01
Full Text Available The article proposes a method of mathematical simulation of electrical machines with thyristor exciters on the basis of the local Fourier transform. The present research demonstrates that this method allows switching from a variable structure model to a constant structure model. Transition from the continuous variables to the discrete variables is used. The numerical example is given in the paper.
Fedotov, A.; Fedotov, E.; Bahteev, K.
2017-02-01
The article proposes a method of mathematical simulation of electrical machines with thyristor exciters on the basis of the local Fourier transform. The present research demonstrates that this method allows switching from a variable structure model to a constant structure model. Transition from the continuous variables to the discrete variables is used. The numerical example is given in the paper.
A Novel Cogging Torque Simulation Method for Permanent-Magnet Synchronous Machines
Chun-Yu Hsiao; Jonq-Chin Hwang; Sheng-Nian Yeh
2011-01-01
Cogging torque exists between rotor mounted permanent magnets and stator teeth due to magnetic attraction and this is an undesired phenomenon which produces output ripple, vibration and noise in machines. The purpose of this paper is to study the existence and effects of cogging torque, and to present a novel, rapid, half magnet pole pair technique for forecasting and evaluating cogging torque. The technique uses the finite element method as well as Matlab research and development oriented so...
DEFF Research Database (Denmark)
Lascu, Christian; Boldea, Ion; Blaabjerg, Frede
2013-01-01
This paper investigates a permanent magnet synchronous motor drive controlled by a second-order variable structure control technique, known as the super-twisting sliding modes (STSM) control. The STSM controller is designed as a direct torque and flux controller and it works in the stator flux...... reference frame, rather than the rotor frame, as a regular vector control scheme. Another second-order sliding mode controller (SMC) was developed and compared with the STSM controller. Also for comparison, a similar direct torque control scheme based on linear PI controllers was developed and tested....... The tests show that the STSM controller displays very robust behavior, like any SMC, and it works without notable chattering, like the linear PI-based controller. The paper presents theoretical aspects for the STSM control, several design and implementation details, and comparative experimental results...
Discrete Optimal Multirate Techniques for Excitation Controller Design of a Synchronous Machine
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D. I. Pappas
2016-02-01
Full Text Available An optimal control strategy based on Two-Point-Multirate Controllers (TPMRCs, is used to design a desirable excitation controller of a hydrogenerator system, in order to enhance its dynamic stability characteristics. In the TPMRCs based scheme, the control is constrained to a certain piecewise constant signal, while each of the controlled plant outputs is detected many times over a fundamental sampling period T0. On the basis on this strategy, the original problem is reduced to an associate discrete-time linear quadratic (LQ regulation problem for the performance index with cross product terms, for which a fictitious static state feedback controller is needed to be computed. Simulation results for the actual 117 MVA synchronous generator with conventional exciter supplying line to an infinite grid show the effectiveness of the proposed method which has a quite satisfactory performance.
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Zdeněk NOVÁK
2013-12-01
Full Text Available The first part of this paper deals with the measuring of hysteresis loop of the toroidal shape core. LabVIEW software is used to automate this process. The results are compared with the data from the manufacturer and used in the FEMM software for setting parameters of the stator core of Permanent magnet synchronous motor (PMSM. Then, in the second part of this paper, the Lua scripting engine in FEMM software is used to optimize stator tooth width. Program code is written in the Matlab environment and after starting the run process, Matlab uses inter-process communication via ActiveX to connect with FEMM. In this process program tries several options for the stator tooth width. Based on the results, user can evaluate all the data about the overall progress and choose the optimal stator tooth width.
Barka, Noureddine
This project involves a study of sensitivity of the hardness profile of cylindrical bars and spur gears heated by induction using finite element models (axisymmetric and 2D) combined with experimental tests. This sensitivity study is considered as the basic step towards the development of prediction models. The study mainly aims at evaluating the effect of material properties and machine parameters on the hardness profile. As the induction heating is very fast, it is reasonable to assume that the material properties are different from those measured under thermodynamic equilibrium conditions. For this reason, the study attempts to measure the effect of variations in material properties on the surface temperature using the axisymmetric model. The results show that the relative magnetic permeability is the property that most significantly influences surface temperatures and the variation of this property has a large effect on the hardness profile. The effects of specific heat and electrical conductivity are rather low, while the thermal conductivity has a negligible effect on the model developed. Moreover, the variation in temperature of austenitizing margins have limited effects on the developed model. Therefore, the use of material properties at thermodynamic equilibrium was sufficient to establish models for predicting trends. Moreover, study of global sensitivity profile of hardness as a function of machine parameters allowed, in the first place, to compare the two cases of heat to medium and high frequency, by applying them to a disc and a gear and determine the effect of the imposed current density and heating time on the hardness profile using the results of the simulations. It appears that the edge effect is smaller in the MF heating case. In addition, the 2D model can confirm that the MF power heat more the tooth root, while the HF power heat the tooth tip region. Finally, the regression models developed were used to estimate surface temperatures and depths
DEFF Research Database (Denmark)
Mijatovic, Nenad; Jensen, Bogi Bech
2014-01-01
This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the influence of armature reaction on performance of the HTS filed winding. Presented experimental results have confirmed the HTS field winding...... sensitivity to both armature reaction intensity and angular position with respect to the HTS coils. Furthermore, the characterization of the HTS field winding has been correlated to the electromagnetic torque of the machine where the maximal Ic reduction of 21% has been observed for the maximum torque....
Mijatovic, Nenad; Jensen, Bogi Bech
2014-05-01
This paper presents experimental results from the Superwind laboratory setup. Particular focus in the paper has been placed on describing and quantifying the influence of armature reaction on performance of the HTS filed winding. Presented experimental results have confirmed the HTS field winding sensitivity to both armature reaction intensity and angular position with respect to the HTS coils. Furthermore, the characterization of the HTS field winding has been correlated to the electromagnetic torque of the machine where the maximal Ic reduction of 21% has been observed for the maximum torque.
Wu, Zhihong; Lu, Ke; Zhu, Yuan
2015-01-01
The torque output accuracy of the IPMSM in electric vehicles using a state of the art MTPA strategy highly depends on the accuracy of machine parameters, thus, a torque estimation method is necessary for the safety of the vehicle. In this paper, a torque estimation method based on flux estimator with a modified low pass filter is presented. Moreover, by taking into account the non-ideal characteristic of the inverter, the torque estimation accuracy is improved significantly. The effectiveness of the proposed method is demonstrated through MATLAB/Simulink simulation and experiment.
DEFF Research Database (Denmark)
Xie, Ge
parameters such as resistance and inductance are involved in many existing sensorless control algorithms. Therefore, varying machine parameters due to different operation conditions may affect the accuracy of the position estimation and the drive performance consequently. For power converter manufactures...... of the typical sensorless algorithm – the INFORM method is implemented and tested. It is demonstrated that the voltage error may seriously affect the performance of the position estimator. To overcome this difficulty, a new implementation scheme of the INFORM method with easy inverter voltage error compensation......) PWM periods. In the injection period, the voltage output from the inverter is forced to be zero. The rotor position and the speed are then estimated simply from the current changes during this zero voltage injection period. This method provides a good performance for the rotor position estimation...
La réfrigération des grandes machines supraconductrices
Gistau, Guy
1991-02-01
The large scale superconducting devices which are now in operation for deviation of heavy particles, acceleration of light particles or plasma confinement need very large powers of refrigeration. After a short survewing of the different functions of refrigerators and the special requirements for large units, the paper describes some existing or envisaged cooling systems which have an equivalent cooling power in the range of 5 kW at 4.5 K. Les grands appareils de physique utilisant les supraconducteurs demandent des puissances cryogéniques de plus en plus importantes. Après un examen des fonctions élémentaires assurées par un réfrigérateur liées au cahier des charges spécifique à chaque utilisation, les spécificités des grosses unités de réfrigération (fiabilité, efficacité, flexibilité, automatisme) sont mises en évidence. Les solutions proposées dans plusieurs grands projets nécessitant des puissances froides supérieures à 5 kW à 4,5 K sont discutées.
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Zhiyi Song
2012-10-01
Full Text Available The radial-radial flux compound-structure permanent-magnet synchronous machine (CS-PMSM, integrated by two concentrically arranged permanent-magnet electric machines, is an electromagnetic power-splitting device for hybrid electric vehicles (HEVs. As the two electric machines share a rotor as structural and magnetic common part, their magnetic paths are coupled, leading to possible mutual magnetic-field interference and complex control. In this paper, a design method to ensure magnetic decoupling with minimum yoke thickness of the common rotor is investigated. A prototype machine is designed based on the proposed method, and the feasibility of magnetic decoupling and independent control is validated by experimental tests of mutual influence. The CS-PMSM is tested by a designed driving cycle, and functions to act as starter motor, generator and to help the internal combustion engine (ICE operate at optimum efficiency are validated.
Transient Control of Synchronous Machine Active and Reactive Power in Micro-grid Power Systems
Weber, Luke G.
power. The scope of this work is to • develop a mathematical model for a salient pole, 2 damper winding synchronous generator with d axis saturation suitable for transient analysis, • develop a mathematical model for a voltage regulator and excitation system using the IEEE AC8B voltage regulator and excitation system template, • develop mathematical models for an energy storage primary control system, LC filter and transformer suitable for transient analysis, • combine the generator and energy storage models in a micro-grid context, • develop mathematical models for electric system components in the stationary abc frame and rotating dq reference frame, • develop a secondary control network for dispatch of micro-grid assets, • establish micro-grid limits of stable operation for step changes in load and power commands based on simulations of model data assuming net load on the micro-grid, and • use generator and electric system models to assess the generator current magnitude during phase-to-ground faults.
Methodes de compensation des erreurs d'usinage utilisant la mesure sur machines-outils
Guiassa, Rachid
On-machine measurement process is used to inspect the part immediately after the cut without part removal and additional setups. It detects the machining defects visible to the machine tool. The system machine-tool-part deflection and the cutting tool dimension inaccuracy are the most important sources of these defects. The machined part can be inspected, at the semi-finishing cut level to identify systematic defects that may occur later at the finishing cut. Therefore, corrective actions can be derived to anticipate the expected error in order to produce a part with acceptable accuracy. For industrial profitability, the measurement and the compensation tasks must be done under the closed door machining requirement without human interventions. This thesis aims to develop mathematical models that use the data inspection of previous cuts to formulate the compensation of the finishing-cut. The goal of the compensation is to anticipate the expected error which is identified under two components. One is independent on the depth of cut and is related to the cutting tool dimension such as the wear. The other is dependent on the cutting depth such as the deflection. A general model is presented which relies solely on-machine probing data from semi-finishing cuts to compensate the final cut. A variable cutting compliance coefficient relates the total system deflection to the depth of cut in multi-cut process. It is used to estimate the compensation of the tool path. The model is able to take into account the effect of the cutting depth variation and the material removal in the estimation of the error at the finishing-cut. In order to generate the continuous compensated tool path from discrete measurements, a B-Spline deformation technique is adapted to the available data and applied to compute the compensated tool path according to a restricted number of discrete compensation vectors. The results show that the on-machine probed errors can be significantly reduced using the
Abdessemed, Rachid
2012-01-01
L'ouvrage est une présentation détaillée des différents types d'enroulement des machines électriques (tournantes et transformateurs), explicitant leurs domaines d'utilisation, leurs avantages et inconvénients respectifs ainsi que leurs spécificités. Ce panorama est accompagné d'une méthode généralisée de conception. Il est complété par l'exposé des méthodes de mise en encoches manuelles et automatisées qui leurs sont associées. Le document est élaboré avec un minimum de texte au profit d'une illustration évolutive permettant une assimilation efficace. Les enroulements sont représentés sous une forme originale, simple et aisément assimilable. Le livre est principalement destiné aux étudiants du domaine électrotechnique intéressés par la conception et la fiabilité des machines électriques. Par son caractère didactique et son accessibilité aux élèves des écoles techniques, il sera également d'une grande utilité pour un large public professionnel allant du technicien à l'in...
Commande numérique de moteurs synchrones à aimants permanents de faible puissance
Robyns, B.; Fu, Y.; Labrique, F.; Buyse, H.
1995-08-01
High performance motion control with permanent magnet synchronous actuators needs complex control strategies. These control strategies lead frequently to algorithms requiring powerful microprocessors for their digital implementation. In this paper, we consider an approach of the control of small power permanent magnets synchronous actuators which allows to design and to implement control algorithms requiring only a reduced computation power, while maintaining satisfactory static and dynamic performance and a good insensitivity to perturbations and parameter uncertainties. L'actionnement électrique à hautes performances par moteurs synchrones à aimants permanents impose des stratégies de commande évoluées liées au comportement dynamique complexe de ces machines. Ces stratégies de commande conduisent fréquemment à des algorithmes dont l'implantation numérique exige des microprocesseurs ayant une puissance de calcul élevée. Dans cet article, nous développons une approche du problème de la commande des moteurs synchrones à aimants permanents de faible puissance qui permet de concevoir et d'implanter des algorithmes de commande ne nécessitant qu'une puissance de calcul réduite, tout en garantissant des performances statiques et dynamiques satisfaisantes ainsi qu'une bonne insensibilité aux perturbations agissant sur le système et aux incertitudes sur les paramètres.
Assaad, Bassel; El Kadri Benkara, Khadija; Vivier, Stéphane; Friedrich, Guy; Michon, Antoine
2016-01-01
International audience; Cet article propose une démarche méthodologique de réduction de modèles thermiques des machines électriques par analyse de sensibilité locale. Ces modèles sont basés sur l'approche nodale, où un circuit à constantes localisées est construit pour la machine avec plusieurs paramètres qui caractérisent les différents échanges thermiques. L'analyse locale quantifie l'impact des petites variations de ces paramètres autour de leurs valeurs initiales sur les températures du m...
Prieto Rodriguez, Dany
2015-01-01
This thesis focuses on the study of a structure of permanent magnet electric motor which reduces the amount used of permanent magnets composed of rare earths and which can be used in industrial applications. In the first part of the research work, it is shown that the permanent magnet assisted synchronous reluctance machine is a good alternative. A parametric analyse is realised using a finite element modelling in order to highlight the peculiarities of its electromagnetic behaviour. Then, an...
盾构机刀盘多电机同步驱动研究%Synchronously research of the shield machine cutter drive
Institute of Scientific and Technical Information of China (English)
赵刚; 刘德全
2012-01-01
盾构机／5盘由多个电机共同驱动，需要对多电机进行同步控制和负载平衡控制，即让电机速度相同的情况下，承担相应的平均负载。本文描述了多电机同步控制的几种方式，并对各种控制方式的特点进行了比较，同时介绍了中8780土压平衡盾构机刀盘驱动的实际应用。%The shield machine cutter is driven together by several motors. We need to carry on the synchronous and the load balance controls to many motors, then let the motor speed is same under average load. This text described a few methods that many motors synchronously control and compared the characteristics of various control method. At the same time introducing actual application of the q08780 Earth Press Balance shield machine cutter drive.
Directory of Open Access Journals (Sweden)
Alireza Rasekh
2016-11-01
Full Text Available In this paper, a set of correlations for the windage power losses in a 4 kW axial flux permanent magnet synchronous machine (AFPMSM is presented. In order to have an efficient machine, it is necessary to optimize the total electromagnetic and mechanical losses. Therefore, fast equations are needed to estimate the windage power losses of the machine. The geometry consists of an open rotor–stator with sixteen magnets at the periphery of the rotor with an annular opening in the entire disk. Air can flow in a channel being formed between the magnets and in a small gap region between the magnets and the stator surface. To construct the correlations, computational fluid dynamics (CFD simulations through the frozen rotor (FR method are performed at the practical ranges of the geometrical parameters, namely the gap size distance, the rotational speed of the rotor, the magnet thickness and the magnet angle. Thereafter, two categories of formulations are defined to make the windage losses dimensionless based on whether the losses are mainly due to the viscous forces or the pressure forces. At the end, the correlations can be achieved via curve fittings from the numerical data. The results reveal that the pressure forces are responsible for the windage losses for the side surfaces in the air-channel, whereas for the surfaces facing the stator surface in the gap, the viscous forces mainly contribute to the windage losses. Additionally, the results of the parametric study demonstrate that the overall windage losses in the machine escalate with an increase in either the rotational Reynolds number or the magnet thickness ratio. By contrast, the windage losses decrease once the magnet angle ratio enlarges. Moreover, it can be concluded that the proposed correlations are very useful tools in the design and optimizations of this type of electrical machine.
Institute of Scientific and Technical Information of China (English)
LU Qiang; MEI ShengWei; ZHENG ShaoMing
2007-01-01
To verify the performance of NR-PSS (Nonlinear Robust Power System Stabilizer) for large synchronous generators, field experiments were carried out on a 300 MW generator in Baishan Hydro Plant of Northeast China Power Grid. The experiment results show that NR-PSS can improve the generator damping and enhance system stability remarkably.
Energy Technology Data Exchange (ETDEWEB)
Silva, J.C.; Colvara, L.D. [Universidade Estadual Paulista (FEIS/UNESP), Ilha Solteira, SP (Brazil). Dept. de Engenharia Eletrica], Emails: jadiel_silva@hotmail.com, laurence@dee.feis.unesp.br
2009-07-01
The problem of stability of electric power systems, from the standpoint of ability to sync and how FACTS (Flexible Alternating Current Transmission Systems) devices affect this ability in particular the TSCS (Thyristor Controlled Series Compensator) inserted into an environment multi machine, is addressed. The effects of this device on the power synchronizing are considered through analysis of the matrix admittance of the bar, focusing on the transfer admittances between machines.
Energy Technology Data Exchange (ETDEWEB)
Gennari, Jorge L.; Vasconcellos, Alexandre S. de [Figener Engenheiros Associados (Brazil)
1996-07-01
Generators and synchronous motors may supply the necessary power factor correction, which tends to turn unnecessary the installation of capacitors. However, it is necessary to calculate how much more the company will pay in electric power bill when the stop of such machinery be necessary, either in a programed or emergency situation. Therefore, the decision of installing capacitors depends on this calculation. This work shows some criteria and results of a study case. 3 figs., 6 tabs.
Patrimoine technique méconnu des mines d’Alsace et de Moselle : les machines d’extraction
Directory of Open Access Journals (Sweden)
Chip Buchheit
2007-03-01
Full Text Available Cet article dresse un bref historique des machines d’extraction et rappelle les grandes étapes de leur évolution technique. Les résultats des recensements du patrimoine minier réalisés dans le bassin houiller lorrain et dans le bassin potassique alsacien ont permis de distinguer les éléments représentatifs et remarquables de ce patrimoine méconnu et insuffisamment considéré.This article offers a brief history of winding engines and of the principal stages in their technical evolution. Inventory surveys carried out in the Lorraine coal basin and in the region of potassium mines in Alsace allow for an identification of the representative engines and of the remarkable ones, all of them part of a little studied and much neglected industrial heritage.
Directory of Open Access Journals (Sweden)
ABDI, B.
2009-10-01
Full Text Available Electro-mechanical batteries have important advantages as compared with chemical batteries, especially in low earth orbit satellites applications. High speed slotless external rotor permanent magnet machines are used in these systems as Motor/Generator. Proper material and structure for space applications are introduced. A simplified analytic design method is given for this type of machines. Finally, the optimization of machine in order to have maximum efficiency and minimum volume and weight are given in this paper. Particle swarm optimization is used as the optimization algorithm and the finite element-based simulations are used to confirm the design and optimization process and show less than 1.2% error in parametric design.
无刷同步电机的起动性能仿真%Simulation of Brushless Synchronous Machine's Starting Performance
Institute of Scientific and Technical Information of China (English)
李岩; 张超; 刘陵顺
2012-01-01
For the situation that the brushless synchronous machine used to run less in starting status, this paper designs a brushless synchronous motor's simulation model in start running state. The motor starting system as the study object of the model, the use of modular thinking, were established exciter, main generator, rotating rectifier and control units and other modules, the use of these modules and build a complete start-run model, and that the model simulation studies for the early start. Simulation results show that the model has some feasibility and validity, for further study the starting performance of brushless synchronous motor lay foundation.%针对目前国内无刷同步电机较少应用于电动运行的现状,设计一种无刷同步电机起动运行状态的仿真模型.该模型以电机起动系统为研究对象,利用模块化思路,分别建立励磁机、主发电机、旋转整流器以及控制单元等模块,运用这些模块搭建一个完整的起动运行模型,并对所建立的模型进行起动初期的仿真研究.仿真结果表明:该模型有一定的可行性和有效性,能为进一步研究无刷同步电机的起动性能奠定基础.
Directory of Open Access Journals (Sweden)
Ayel J.
2006-11-01
Full Text Available La machine à engrenages FZG reste l'appareil de laboratoire le plus utilisé pour l'évaluation de la capacité de charge des lubrifiants pour engrenages et transmissions. Mais, les différentes méthodes normalisées actuellement utilisées ne sont pas assez sévères pour bien discriminer les huiles extrême-pression actuelles en ce qui concerne leur capacité de charge. L'institut Français du Pétrole a développé une méthode beaucoup plus sévère, tout en restant aussi répétable que les méthodes classiques, sans modification de la machine ou des engrenages et, par conséquent, aisément utilisable dans tous les laboratoires. Cette nouvelle procédure est applicable à vitesse double de la vitesse normale sans accroissement de l'état des contraintes des dentures. L'utilisation de cette méthode devrait rendre de grands services aux formulateurs d'huiles et aux fabricants d'additifs pour la mise au point de leurs produits. The FZG gear machine is still the most widely used laboratory device for assessing the load-carrying capacity of lubricants for gears and transmissions. But various standardized methods currently used are not severe enough to effectively discriminate present extreme- pressure oils with regard to their load-carrying capacity. The Institut Français du Pétrole has developed a much more severe method that remains just as repeatable as conventional methods, without modifying the machine or the gears, and hence that can easily be used in all laboratories. This new procedure can be implemented at twice normal speed without any increase in the state of stresses on teeth. The use of this method should be of great service to oil formulators and additive manufacturers in the development of their products.
DEFF Research Database (Denmark)
Knudsen, Hans
1995-01-01
in the stator. A consistent method is developed to determine model parameters from standard machine data. A phasor model of the line commutated converter is presented. The converter model includes not only the fundamental frequency, but also any chosen number of harmonics without a representation of the single...
Energy Technology Data Exchange (ETDEWEB)
Costa Bortoni, Edson da; Jardini, Jose Antonio [Sao Paulo Univ., SP (Brazil). Escola Politecnica
1995-12-31
This work presents the development of a equipment to be used for the determination of synchronous machines parameters though the frequency response method. The methodology is presented. A case study based on literature data is presented 9 figs., 2 tabs., 7 refs.
Belqorchi, Abdelghafour
Forty years after Watson and Manchur conducted the Stand-Still Frequency Response (SSFR) test on a large turbogenerator, the applicability of this technic on a powerful salient pole synchronous generator has yet to be confirmed. The scientific literature on the subject is rare and very few have attempted to compare SSFR parameter results with those deduced by classical tests. The validity of SSFR on large salient pole machines has still to be proven. The present work aims in participating to fill this knowledge gap. It can be used to build a database of measurements highly needed to draw the validity of the technic. Also, the author hopes to demonstrate the potential of SSFR model to represent the machine, not only in cases of weak disturbances but also strong ones such as instantaneous three-phase short-circuit faults. The difficulties raised by previous searchers are: The lack of accuracy in very low frequency measurements; The difficulty in rotor positioning, according to d and q axes, in case of salient pole machines; The measurement current level influence on magnetizing inductances, in axes-d and; The rotation impact on damper circuits for some rotors design. Aware of the above difficulties, the author conducted an SSFR test on a large salient pole machine (285 MVA). The generator under test has laminated non isolated rotor and an integral slot number. The damper windings in adjacent poles are connected together, via the polar core and the rotor rim. Finally, the damping circuit is unaffected by rotation. To improve the measurement accuracy, in very low frequencies, the most precise frequency response analyser available on the market was used. Besides, the frequency responses of the signals conditioning modules (i.e., isolation, amplification...) were accounted for to correct the four measured SSFR transfer functions. Immunization against noise and use of instrumentation in their optimum range, were other technics rigorously applied. Magnetizing inductances
Tlili, Iskander; Timoumi, Youssef; Ben Nasrallah, Sassi
2007-01-01
International audience; La recherche du cycle moteur à rendement élevé, à faible pollution et à multisources d'énergie a conduit à réévaluer le cycle de Stirling. Plusieurs prototypes du moteur ont été réalisés mais leurs performances restent faibles. Des études montrent que le régénérateur est le compartiment le plus important pour l'amélioration des performances du moteur. Ainsi pour optimiser les paramètres géométriques et physiques du régénérateur un programme numérique de simulation tena...
Institute of Scientific and Technical Information of China (English)
宋亚林
2015-01-01
This paper discusses the hydraulic open loop and closed loop system and its characteristics of synchronous control. The Application of hydraulic closed loop synchronization control system in hydraulic type three roller symmetrical bending machine was introduced in this paper.%论述了液压开环与闭环同步控制系统及其特点，并对液压闭环同步控制系统在液压式三辊对称卷板机中的应用进行了介绍。
Directory of Open Access Journals (Sweden)
Paulo S. G. Magalhães
2008-06-01
Full Text Available Um dos problemas encontrados na colheita mecanizada da cana-de-açúcar é a falta de sincronismo entre a colhedora e o transbordo, ocasionando perdas tanto de material como de capacidade operacional. A presente pesquisa teve como objetivo desenvolver um sistema capaz de auxiliar no sincronismo entre a colhedora e o veículo de transbordo por meio de comunicação sem fio. Dois sensores de ultra-som acoplados ao elevador e um microprocessador gerenciam tais informações, gerando correta sincronia entre as máquinas. O sistema foi testado em laboratório e em campo, cumprindo corretamente a função de manter as máquinas em sincronia, indicando e alertando aos operadores as suas posições relativas. O sistema desenvolvido reduziu as perdas de rebolo em cerca de 60 kg ha-1, comparado com a colheita realizada com o sistema desligado.One of the problems found in mechanical harvest of sugar cane is the lack of synchronism between the harvest machine and the infield wagon, causing crop losses as well as operational capacity. The objective of the present research was to design a system capable of helping to synchronize the sugar cane harvest machine with the wagon. The communication between tractor and harvest machine is wireless. Two ultrasound sensors coupled to the elevator and a microprocessor manage such information, generating a correct synchronization among the machines. The system was tested in laboratory and on field performing its function adequately, maintaining the two machines in synchronization, indicating and alerting the operators their relative positions. The developed system reduced the sugar cane lost in 60 kg ha-1 comparing to the harvest with the system turned off.
Synchronicity from Synchronized Chaos
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Gregory S. Duane
2015-03-01
Full Text Available The synchronization of loosely-coupled chaotic oscillators, a phenomenon investigated intensively for the last two decades, may realize the philosophical concept of “synchronicity”—the commonplace notion that related eventsmysteriously occur at the same time. When extended to continuous media and/or large discrete arrays, and when general (non-identical correspondences are considered between states, intermittent synchronous relationships indeed become ubiquitous. Meaningful synchronicity follows naturally if meaningful events are identified with coherent structures, defined by internal synchronization between remote degrees of freedom; a condition that has been posited as necessary for synchronizability with an external system. The important case of synchronization between mind and matter is realized if mind is analogized to a computer model, synchronizing with a sporadically observed system, as in meteorological data assimilation. Evidence for the ubiquity of synchronization is reviewed along with recent proposals that: (1 synchronization of different models of the same objective process may be an expeditious route to improved computational modeling and may also describe the functioning of conscious brains; and (2 the nonlocality in quantum phenomena implied by Bell’s theorem may be explained in a variety of deterministic (hidden variable interpretations if the quantum world resides on a generalized synchronization “manifold”.
Réduction active des vibrations et des bruits d'une machine électrique par la stratégie de commande.
Geoffriault, Maud
2015-01-01
This work takes place in the context of the development of powertrains for electric vehicles. Those developments have raised new issues such as noise and vibrations of electrical machines, which are important issues in automotive applications. The aim of this thesis is to develop control laws dedicated to the reduction of currents harmonics that are responsible for vibration harmonics.In that purpose, different parts of the system have been modelled. Parameters of the electrical model of the ...
Duchesne, R. M.; And Others
Because of data ownership questions raised by the interchange and sharing of machine readable bibliographic data, this paper was prepared for the Bibliographic and Communications Network Committee of the National Library Advisory Board. Background information and definitions are followed by a review of the legal aspects relating to property and…
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Taha Zaghdoudi
2016-09-01
Full Text Available Ces dernières années, la succession des crises bancaires, qui dans la plupart ont été soldées par des pertes économiques et financières énormes, a suscité l’intérêt de plusieurs chercheurs. Empiriquement, ces auteurs ont opté pour des modèles d’alerte précoce (Early Warning System pour prévenir leurs occurrences. L’objectif de ce papier est de construire un Modèle d’alerte des crises bancaires basé sur une approche hybride. Sur la base des données relatives à 22 pays qui ont subi des crises bancaires observées sur la période 1990–2011, nous avons développé un modèle d’alerte des crises bancaires. Ce modèle est basé sur une approche hybride Bayesian model averaging–Support vectors machine. Sur les 25 variables explicatives retenues, les résultats empiriques du modèle hybride ont fait ressortir 9 indicateurs qui sont considérés comme les principaux facteurs déterminants du déclenchement des crises bancaires. Ces derniers ont une probabilité postérieure d’inclusion supérieure à 0,5. Ces indicateurs potentiels sont la rentabilité nette des actifs, la compétitivité de l’intermédiation bancaire, les provisions sur les créances douteuses, les investissements directs étrangers, la concentration bancaire, la stabilité financière des banques, les produits nets financiers, le taux d’intérêt réel et le taux d’inflation.
Energy Technology Data Exchange (ETDEWEB)
Chassany, J.Ph. [CEA Marcoule, Centre de Production de Plutonium, 30 (France)
1964-07-01
A stratified blowing-machine has been built making it possible to introduce into the tests a vertical temperature gradient. The similitude conditions have been examined. The development tests have made it possible to observe and to film the shape of the smoke pall emitted by a chimney in different cases. Stationary waves have been obtained in steady state conditions and the cross-section of the pall has also been studied. It appears that certain diffusion studies justify the use of a stratified blowing-machine. (author) [French] Une soufflerie stratifiee permettant d'introduire dans les experimentations le gradient vertical de la temperature a ete realisee. Les conditions de similitude ont ete examinees. Des essais de mise au point ont permis d'observer et de filmer l'allure du panache de fumee emis par une cheminee dans differents cas. La formation d'ondes stationnaires en regime stable a ete obtenue et la section droite du panache a ete egalement etudiee. Il apparait que certaines etudes de diffusion doivent justifier l'emploi d'une soufflerie stratifiee. (auteur)
Prévost, David; Louf, François; Rouch, Philippe
2011-01-01
To achieve better performances in term of productivity, High Speed Machining centers have increasing kinematical characteristics. High accelerations caused by the trajectory execution dynamically load mechanical structure, axes and joints. Such deformations of mechanical components a ect the actual position of the tool in the machining frame. Hence, these gemetrical deviations make the machined geometry of the part vary from the expected one. Within the context of managing the HSM process, this study develops a framework and choice of nite element model to evaluate the structure dynamical behavior of a HSM center. Based on the proposed model, a calculation method is detailed to evaluate the geometrical deviations induced by the trajectory execution. The presented works can thus be used as a tool for the structure design of machine, the adjustment and the optimization of kinematical parameters for machining. --- Pour atteindre des performances accrues en terme de productivit\\'e, les centres d'Usinage Grande Vi...
Directory of Open Access Journals (Sweden)
Orlando Lázaro Rodríguez González
2011-02-01
Full Text Available Este trabajo resuelve, haciendo uso de las facilidades que brinda el MATLAB, de forma cuasi analítica,este problema.El software sigue los mismos pasos que realiza manualmente por el método tradicional. Fueimplementado el método de la fuerza magnetomotriz. Para el ajuste de la curva en el tramo saturado seemplea una aproximación según la función arcotangente, en el sentido de los mínimos cuadrados. Elpunto intercepción entre curvas se calcula con métodos numéricos, hasta una precisión que supera la quepueden tener los datos del experimento. Está destinado para su uso en la industria y para la docencia enlas universidades Synchronous Machine tests, such as no load, short circuit and zero power factor, are achieved to traceZero Power-factor, Regulation and External Load characteristics, in addition to Voltage Regulation for anygiven state. To carry out this results we are familiarized with graphical methods, which are cumbersomeand imprecise. This is a new cuasi analytic approach to this problem by means of a MATLAB software.Algorithm is similar to that followed by someone who is carrying out solutions by traditional way. It wasimplemented Magneto Motriz Force method. Saturation was approached to an inverse tangent curve in aleast means square sense. To compute the interception point between curves it was used numericalmethods which achieved a precision higher than experiments offer.This software is intended to be usedeither in Indutry or in universities with academic purpose.
Energy Technology Data Exchange (ETDEWEB)
Dubois, Ph.; Gagnor, A. [Intercontrole, 94 - Rungis (France)
2001-07-01
The product software CIVACUVE is used by INTERCONTROLE for the analysis of UT examinations, for detection, performed by the In-Service Inspection Machine (MIS) of the vessels of nuclear power plants. This software is based on an adaptation of an algorithm of SEGMENTATION (CEA CEREM), which is applied prior to any analysis. It is equipped with tools adapted to industrial use. It allows to: - perform image analysis thanks to advanced graphic tools (Zooms, True Bscan, 'contour' selection...), - backup of all data in a database (complete and transparent backup of all informations used and obtained during the different analysis operations), - connect PC to the Database (export of Reports and even of segmented points), - issue Examination Reports, Operating Condition Sheets, Sizing curves... - and last, perform a graphic and numerical comparison between different inspections of the same vessel. Used in Belgium and France on different kind of reactor vessels, CIVACUVE has allowed to show that the principle of SEGMENTATION can be adapted to detection exams. The use of CIVACUVE generates a important time gain as well as the betterment of quality in analysis. Wide data opening toward PC's allows a real flexibility with regard to client's requirements and preoccupations.
New neural synchronization learning rule based on tree parity machine%基于树形奇偶机的神经网络同步新学习规则
Institute of Scientific and Technical Information of China (English)
梁一峰; 廖晓峰; 任晓霞
2013-01-01
To solve the low speed of synchronization, a new learning rule was proposed by employing Tree Parity Machine (TPM). By setting queues to record the results of each communication in the synchronization process, this rule estimated the degree of synchronization of the two TPMs communicating with each other in real time. According to the results of estimation, the rule selected appropriate values to modify the weights, appropriately increased weight modifications in the lower degree of synchronization and reduced weight modifications in the higher degree of synchronization. Finally, the simulation results show that synchronization efficiency is improved more than 80% by applying new learning rule. Meanwhile, it is also indicated that the rule is computationally inexpensive and it improves the security of communication compared to the classic learning rules.%针对神经密码同步速度慢的问题,基于树形奇偶机(TPM),提出修改权值的新规则,在同步过程中设置队列用来记录每次通信的结果,实时估计两个互相通信的树形奇偶机的同步程度,并根据估计的结果决定权值修改幅度,在同步程度较低时适当增大权值修改量,在同步程度较高时适当减小权值修改量.仿真实验结果表明,应用新学习规则后同步效率提高了80％以上,同时与几种经典学习规则相比,计算开销更小,安全性得到进一步提高.
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de la Barrière O.
2009-11-01
Full Text Available the best ways in order to reduce fuel consumption for vehicles. It consists of associating an electric motor next to the classical thermal machine. In this embedded system, the efficiency and the torque per unit mass are very important. So it seems to be a good idea to use a permanent magnet synchronous machine, which is recognized for satisfying these two objectives. Since the allocated volume is rather flat, axial flux topologies are interesting. This paper’s goal is to propose an optimal first design method for such structures, given the allocated volume and the machine requirements. La traction hybride semble actuellement un des moyens les plus prometteurs pour réduire la consommation de carburant des véhicules. Ce procédé consiste à associer un moteur électrique au moteur thermique traditionnel. Pour une telle application embarquée, le rendement, ainsi que le couple massique, sont des critères de conception de première importance. Dans ce contexte, le recours à une machine synchrone à aimants permanents, reconnue pour satisfaire ces deux critères, semble être approprié. Vu que le volume alloué à la machine électrique est de forme discoïde, les topologies à flux axial semblent les plus intéressantes. L’objectif de cet article est de proposer une méthodologie de pré-dimensionnement de tels actionneurs, en ayant fixé au préalable le volume maximal permis ainsi que le cahier des charges de la machine.
Directory of Open Access Journals (Sweden)
Louise Sauvé
2008-01-01
Full Text Available Apprendre tout au long de la vie amène de plus en plus les adultes, confrontés au fait de devoir concilier emploi, travail et études, à rechercher des solutions de formation à la carte selon des horaires fragmentés, près de leur lieu de travail ou de leur milieu de vie. Les technologies Web s’avèrent des outils par excellence pour soutenir ces formations puisqu’elles offrent flexibilité, accessibilité, communication et interaction tout en permettant une variété d’approches éducatives. Cet article présente le contexte et les résultats d’une étude de cas auprès de formateurs en milieu de travail ainsi que le programme de formation personnalisé de formateurs en ligne, Form@tion.
Energy Technology Data Exchange (ETDEWEB)
Multon, B.
1994-05-15
This work deals with the optimization of double salience variable reluctance motors with electronic switching. It includes the control laws, the electromagnetic structure and the direct and indirect self-driving sensors. The first chapter presents the state-of-the-art of double salience reluctance machines, their characteristics, their inverters and the evolutions of their electromagnetic structure. Chapters 2 and 3 treat of the optimization of power supplies and of the electromagnetic structure, respectively. Finally, the last chapter treats of original solutions of position measurement for the self-control, one using a variable reluctance sensor, and the other using an indirect sensor. The impact of the motor characteristics on the power supply has been analyzed with the optimization of the control laws in permanent regime and low torque undulation regime. The influence of the motor structure geometry on the electromagnetic characteristics has been studied using analytic methods coupled with punctual finite-element calculations. Using a particular example, a self-oscillating power supply mode has been implemented in order to reduce the losses and the electromagnetic pollution. (J.S.)
The rediscovery of synchronous reluctance and ferrite permanent magnet motors tutorial course notes
Pellegrino, Gianmario; Bianchi, Nicola; Soong, Wen; Cupertino, Francesco
2016-01-01
This book offers an essential compendium on the analysis and design of synchronous motors for variable-speed applications. Focusing on synchronous reluctance and ferrite permanent-magnet (PM) synchronous reluctance machines, it provides a broad perspective on three-phase machines for variable speed applications, a field currently dominated by asynchronous machines and rare-earth PM synchronous machines. It also describes synchronous reluctance machines and PM machines without rare-earth materials, comparing them to state-of-the-art solutions. The book provides readers with extensive information on and finite element models of PM synchronous machines, including all relevant equations and with an emphasis on synchronous-reluctance and PM-assisted synchronous-reluctance machines. It covers ferrite-assisted machines, modeled as a subcase of PM-assistance, fractional slot combinations solutions, and a quantitative, normalized comparison of torque capability with benchmark PM machines. The book discusses a wealth o...
Directory of Open Access Journals (Sweden)
Stéphanie Ginalski
2011-12-01
Full Text Available Cette contribution a pour but d’intégrer à l’analyse des interconnexions entre conseils d’administration (interlocks, méthode fréquemment employée pour étudier les liens entre les firmes, un angle d’approche centré sur la question des entreprises familiales, généralement peu prise en compte dans ce type d’études. Pour ce faire, cette recherche se focalise sur 22 grandes firmes de l’industrie suisse des machines, de l’électrotechnique et de la métallurgie (MEM, dont les membres des conseils d’administration et les directeurs généraux ont été recensés pour 5 dates couvrant le siècle (1910, 1937, 1957, 1980 et 2000. L’analyse de réseau vise à retracer l’évolution des liens entretenus par ces 22 sociétés au sein des 110 plus grandes firmes helvétiques. Nos résultats montrent que jusqu’aux années 1980, les interlocks deviennent de plus en plus denses et représentent un mécanisme de coordination pour les élites économiques, les entreprises familiales et les dirigeants familiaux se trouvant, avec les banques, au cœur de ce système. Les deux dernières décennies du siècle sont cependant marquées par l’érosion relative du capitalisme familial, le retrait du secteur bancaire dans le réseau interfirmes et le déclin significatif des interlocks.
Loi de commande prédictive pour le positionement des axes d'une machine outil à architecture ouverte
Susanu, Mara; Dumur, Didier; Tournier, Christophe; Lartigue, Claire
2004-01-01
National audience; Résumé : Concevoir une CN pour machine-outil selon une structure à architecture ouverte permet d'en améliorer la flexibilité en autorisant l'intégration de modules spécifiques. Dans ce contexte, l'article envisage en premier lieu l'ajout d'un module de commande d'axe basé sur une stratégie prédictive avancée. Cette stratégie incluant une anticipation en boucle fermée s'avère particulièrement performante en termes de suivi de consigne et de facilité d'implantation. Considéra...
Sur la commande tolérante aux défauts des machines asynchrones : Une approche implicite
Benzineb, Omar; Tadjine, Mohamed; Benbouzid, Mohamed; Diallo, Demba
2012-01-01
International audience; Dans cet article, deux approches de commande tolérante aux défauts (FTC Fault-Tolerant Control) sont étudiées et appliquées à la machine asynchrone. Dans ce contexte, la phase de détection et d'isolation du défaut est décalée par rapport à la phase de reconfiguration de la commande. Celle-ci est réalisée en testant l'état d'un modèle interne qui s'active automatiquement dès l'apparition d'un défaut pour compenser son effet. Cet effet peut être convenablement modélisé p...
Institute of Scientific and Technical Information of China (English)
蔡然; 杨俊华; 杨梦丽; 潘观海
2015-01-01
In order to identify the parameters of the synchronous machine , the relationship of the d , q-axis flux link-age with stator current and excitation voltage was studied , and a model of the synchronous machine was built with cur-rent as state variables .By analyzing the standstill frequency response curves , the gain and phase of different parame-ters with various frequencies were obtained so as to replace the relevant parts in the characteristic transfer function e -quations which represented the d , q-axis electromagnetic parameters .The mathematic model and the state-space equa-tions of the synchronous machine were simplified .The data processing method was improved and the parameters of the machine were identified based on the status analysis results of the machine at the open field excitation winding and the open stator winding .The parameters had better consistency than the measured parameters with other test methods , and therefore the effectiveness of the proposed parameter identification method was verified .%针对同步电机参数辨识问题，以全电流为状态变量，研究同步电机d、q轴磁链与定子电流及励磁电压的关系，建立电机的数学模型。通过分析静止频率响应试验曲线，获得不同频率下各测试参数的增益和相位，替换d、q轴电磁参数特性传递函数方程中的相关部分，简化电机数学模型及其状态空间方程。基于励磁和定子回路开路时电机状态的分析结果，改进数据处理过程，辨识电机参数，对比采用其它方法测取的结果，有较好的一致性，所提参数辨识方法的有效性得以验证。
Khanbaghi, Maryam
Increasing closure of white water circuits is making mill productivity and quality of paper produced increasingly affected by the occurrence of paper breaks. In this thesis the main objective is the development of white water and broke recirculation policies. The thesis consists of three main parts, respectively corresponding to the synthesis of a statistical model of paper breaks in a paper mill, the basic mathematical setup for the formulation of white water and broke recirculation policies in the mill as a jump linear quadratic regulation problem, and finally the tuning of the control law based on first passage-time theory, and its extension to the case of control sensitive paper break rates. More specifically, in the first part a statistical model of paper machine breaks is developed. We start from the hypothesis that the breaks process is a Markov chain with three states: the first state is the operational one, while the two others are associated with the general types of paper-breaks that can take place in the mill (wet breaks and dry breaks). The Markovian hypothesis is empirically validated. We also establish how paper-break rates are correlated with machine speed and broke recirculation ratio. Subsequently, we show how the obtained Markov chain model of paper-breaks can be used to formulate a machine operating speed parameter optimization problem. In the second part, upon recognizing that paper breaks can be modelled as a Markov chain type of process which, when interacting with the continuous mill dynamics, yields a jump Markov model, jump linear theory is proposed as a means of constructing white water and broke recirculation strategies which minimize process variability. Reduced process variability comes at the expense of relatively large swings in white water and broke tanks level. Since the linear design does not specifically account for constraints on the state-space, under the resulting law, damaging events of tank overflow or emptiness can occur. A
Design of rotating electrical machines
Pyrhonen , Juha; Hrabovcova , Valeria
2013-01-01
In one complete volume, this essential reference presents an in-depth overview of the theoretical principles and techniques of electrical machine design. This timely new edition offers up-to-date theory and guidelines for the design of electrical machines, taking into account recent advances in permanent magnet machines as well as synchronous reluctance machines. New coverage includes: Brand new material on the ecological impact of the motors, covering the eco-design principles of rotating electrical machinesAn expanded section on the design of permanent magnet synchronous machines, now repo
Energy Technology Data Exchange (ETDEWEB)
Chou, S.Y. [ELETRONORTE, Brasilia (Brazil); Liu, H. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia; Pedroso, A. de [CEPEL, Rio de Janeiro, RJ (Brazil)
1991-12-31
The performance of an adapted stabilizer additional sign for a synchronous power generator connected to an infinite bar is analysed. The operation modus of the system is fully explained and its theoretical basis is described. A comparison between the performance of the adapted system and a conventional one is performed. 8 refs., 18 figs., 1 tab.
Institute of Scientific and Technical Information of China (English)
苏颖毅
2012-01-01
A layout scheme of the electric drive system of a pure electric vehicle was introduced in this paper.The longitudinal dynamics model of the electric vehicle was built , from which the driving resistance was derived and then transformed to an equivalent resistance torque on the axis of the electric machine .The mathe-matical model of a permanent magnet synchronous machine was built in the two phase rotating reference frame and the motion equation of the electric machine with respect to the driving resistance was given .The necessity of the flux -weakening control was pointed out according to the voltage and current limitations of the three phase in -verter.A surface mounted permanent magnet synchronous machine was chosen and the relative flux -weakening control was put forward.By means of the simulation in Matlab /Simulink it was concluded that the flux -weake-ning control can effectively widen the rotational speed range of the electric machine , which can raise the maxi-mum speed of the electric vehicle.% 介绍了一种纯电动车电力驱动系统布置方案。建立电动车纵向动力学模型，得出电动车行驶阻力，并将其等效到电机输出端。在两相旋转坐标系下建立永磁同步电机数学模型，结合电动车行驶阻力，推出电机运动方程。然后选用表贴式永磁同步电机，提出相应的弱磁控制策略。通过在 Matlab/Simulink 中的仿真验证，得出弱磁控制能有效拓宽永磁同步电机转速范围，提升电动车最高运行速度。
Louis, Jean-Paul
2013-01-01
Synchronous motors are indubitably the most effective device to drive industrial production systems and robots with precision and rapidity. Their control law is thus critical for combining at the same time high productivity to reduced energy consummation. As far as possible, the control algorithms must exploit the properties of these actuators. Therefore, this work draws on well adapted models resulting from the Park's transformation, for both the most traditional machines with sinusoidal field distribution and for machines with non-sinusoidal field distribution which are more and more used in
Recent Advances on Permanent Magnet Machines
Institute of Scientific and Technical Information of China (English)
诸自强
2012-01-01
This paper overviews advances on permanent magnet（PM） brushless machines over last 30 years,with particular reference to new and novel machine topologies.These include current states and trends for surface-mounted and interior PM machines,electrically and mechanically adjusted variable flux PM machines including memory machine,hybrid PM machines which uniquely integrate PM technology into induction machines,switched and synchronous reluctance machines and wound field machines,Halbach PM machines,dual-rotor PM machines,and magnetically geared PM machines,etc.The paper highlights their features and applications to various market sectors.
Directory of Open Access Journals (Sweden)
Noureddine Hamouda
2014-03-01
Full Text Available To minimize the total harmonic distortion (THD and improve the power factor (PF, this paper presents a comparative study between two techniques of shunt power active filter (SPAF by a selective action of harmonics. These two techniques are based on the SAPF of certain low frequency harmonics (5th and 7th whose identification of the harmonics of references of the first is made by the axis synchronous d-q of the Park, and the second is done by the approach of self-tuning filter (STF Thereafter, The active simultaneously filtering of the 5th and 7th harmonics of the current of load catches. The shapes of the signals and the THD values resulting from the results of digital simulations (Matlab-Simulink elaborate the effectiveness and the best technique of this type of filtering.
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张超; 李岩; 王冬梅
2011-01-01
This paper introduces a modeling method of Brushless Synchronous Machines' model. A starter/generator system is Based on the model. By analysing the Typical transition process (from no load to load and the load to the three -2phase output short circuit) ,we can prove the correctness and effectiveness of Matlab simulation model.%运用Matlab中的PSB模块库和Simu link模块库,建立了无刷同步电机模型以及该模型的起动发电系统；通过对该系统发电状态下,由空载到负载和由空载到三相输出短路等典型过渡过程仿真分析,证明了所建Matlab仿真模型的正确性和有效性.
Timofeev, Igor; Bazhenov, Maksim; Seigneur, Joseé; Sejnowski, Terrence
2011-01-01
Summary Neuronal synchronization occurs when two or more neuronal events are coordinated across time. Local synchronization produces field potentials. Long-range synchronization between distant brain sites contributes to the electroencephalogram. Neuronal synchronization depends on synaptic (chemical/electrical), ephaptic, and extracellular interactions. For an expanded treatment of this topic see Jasper’s Basic Mechanisms of the Epilepsies, Fourth Edition (Noebels JL, Avoli M, Rogawski MA, Olsen RW, Delgado-Escueta AV, eds) published by Oxford University Press (available on the National Library of Medicine Bookshelf [NCBI] at www.ncbi.nlm.nih.gov/books). PMID:24850952
Institute of Scientific and Technical Information of China (English)
肖甘
2013-01-01
本文以永磁同步电动机为基础,研究了直接滑模电流控制策略,该策略对参数变化以及外界干扰的鲁棒性较强,从而广泛应用于电气传动控制领域.设计了新颖的直接滑模电流控制器代替传统的PI电流控制器,并且采用了开关表查询方式加快了动态响应速度.最后基于TMS320DSP28335控制器对永磁同步电动机直接滑模电流控制控制系统进行实验验证,结果表明所设计的控制器动态响应较快,抗干扰能力较强.%This paper researched on direct sliding mode current control of a permanent magnet synchronous machine.Due to the robustness to parameters variations and external disturbances,sliding mode controllers were widely used for the control of electrical drives.A novel direct sliding mode current controller was designed to substitute the traditional PI current controller,and switch table was used to speed up the dynamic response.As a result,the experiment of permanent magnet synchronous machine direct sliding mode current control system based on TMS320DSP28335 controller was finished.The experimental results illustrate this designed controller has faster dynamic response and stronger anti-interference ability.
Permanent magnet synchronous and brushless DC motor drives
Ramu, Krishnan
2009-01-01
Presents an introduction to machines, power devices, inverters, and control. This book covers pm synchronous machines, including modeling, implementation, control strategies, flux weakening operations, parameter sensitivity, sensorless control, and intelligent control applications.
Directory of Open Access Journals (Sweden)
Porcheron F.
2013-03-01
Full Text Available Amine scrubbing is usually considered as the most efficient technology for CO2 mitigation through postcombustion Carbon Capture and Storage (CCS. However, optimization of the amine structure to improve the solvent properties requires to sample a large number of possible candidates and hence to gather a large amount of experimental data. In this context, the use of QSAR (Quantitative Structure Activity Relationship statistical modeling is a powerful tool as it performs a mapping of a set of input vectors (i.e. the characteristics or the properties of the molecules under consideration to a set of output vectors (i.e. their targeted properties. In this work, we used a high throughput screening experimental device to measure CO2 solubility data on a set of 46 amine aqueous solutions. Absorption isotherms are represented using a thermodynamic model based on two thermodynamic constants, pKa* and pKc* , accounting for the main chemical reactions occurring in the liquid phase between amine and CO2. Then, we used a statistical approach named Graph Machines at the same time to cluster the molecules and to model the variation of the acidity constant pKa* as a function of the molecular structure. The originality of our approach is the use of graphs to represent molecules in multidimensional spaces and simultaneously construct predictive models of their physicochemical properties based on these graphs. This approach is applied in this paper to predict the thermodynamic properties of a set of 5 new molecules. Le procédé d’absorption aux amines est considéré comme la technologie la plus efficace pour limiter les rejets de CO2 dans le cadre du captage en postcombustion puis du stockage du CO2. Cependant, l’optimisation des propriétés du solvant nécessite d’évaluer un grand nombre de candidats potentiels et donc de collecter une quantité importante de propriétés expérimentales. Dans ce contexte, l’utilisation de méthodes de mod
Institute of Scientific and Technical Information of China (English)
李岩; 张超; 王冬梅
2012-01-01
对航空无刷同步电机起动发电系统电动运行的励磁特性进行了理论分析,提出了交直流混合励磁方案,建立了系统的MATLAB/SIMULINK仿真模型。仿真结果表明,主发电机励磁电流平均值随励磁机励磁频率的升高而减小,且主发电机励磁电流脉动率随转速升高有唯一极小值点,该点可作为交直流励磁的切换点。%The excitation characteristic for starter/generator system working on starting process of brushless synchronous machine was analyzed in this paper first,and then a new excitation method is given,it was AC an DC excitation.Based on MATLAB/SIMULINK,the simulation model for the system was built.Simulation results state that the average current of main machine would decrease with the increase of excitation frequency and the rate of variation for excitation current had only one minimum value with the increase of speed,and the value just could be used for switching.
Institute of Scientific and Technical Information of China (English)
闫波; 李佳
2011-01-01
简要介绍飞刀加工汽车同步器齿套滑块槽时存在的弊病,分析了导致切削颤振的原因.测量了飞刀加工时的主切削力,并以此建立其数学模型;通过改变进给量及切削速度的方法改着了切削振动,提高了生产质量和生产效率.%The machining malady in flying culling for the sliding groove of gear sleeve of automotive synchronizer was introduced and the fat-tors loading to fulling chattet were analyzed. The main rutting force in flying cutler machining was measured lo establish a mathenatical model. Results show that culling vibralion in amended by method of varying feed rate and culling speed, and the produe tionn quality and efficiency are improved.
Boussetoua, Mohammed
feeding the hearting system. In recent years, numerous research studies have started on the development of electromechanical system converters for various applications, such as transport by road, rail or aviation. The development of new low-speed, low-weight electric machines and their very high degree of compactness has become a very promising alternative. This project strongly interests many industries in the field of air transport. The transverse flux machine is considered as a compact structure having better mass power compared to other electrical machines. The design of transverse flux machine was the subject of an electromagnetic study. Also, the analytical study helped to determine the overall dimensions of the machine. The study was followed by a validation phase of the analytical model using numerical simulations. These two studies were intended to determine changes in the characteristics of the transverse flux machine according to the different geometric dimensions of its active parts. From the calculations made using analytical and numerical models, a prototype of the transverse flux machine (600 W, 320 RPM) was designed and manufactured in the AMIL laboratory at the Universite du Quebec a Chicoutimi (UQAC). A bench test was conducted to compare the theoretical and experimental results. The measurements obtained on this prototype were compared with the theoretical results. This phase of the study demonstrates with satisfaction, the reliability of the theoretical models developed. Finally, a new configuration of this machine has been proposed. Numerical simulation results of this structure are particularly encouraging and require further investigations. For logistical and financial reasons, the prototype of this configuration has not been manufactured. (Abstract shortened by UMI.)
LHC synchronization test successful
The synchronization of the LHC's clockwise beam transfer system and the rest of CERN's accelerator chain was successfully achieved last weekend. Tests began on Friday 8 August when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered about 3 kilometres around the LHC itself on the first attempt. On Saturday, the test was repeated several times to optimize the transfer before the operations group handed the machine back for hardware commissioning to resume on Sunday. The anti-clockwise synchronization systems will be tested over the weekend of 22 August.Picture:http://lhc-injection-test.web.cern.ch/lhc-injection-test/
Institute of Scientific and Technical Information of China (English)
彭纪昌; 刘卫国; 马鹏; 毛帅
2015-01-01
随着多电飞机、全电飞机的高速发展,三级式航空无刷同步电机因兼顾高功率密度及功率因数可调等优势得到广泛应用.由于三级式电机中主发电机的凸极特性,转子磁场位置的变化会影响定子铁芯的饱和程度,从而造成定子电感值的变化.该文分析了三级电机饱和状态下电感值的变化规律,并在此基础上利用主发电机的凸极特性,采用脉冲式电压注入法进行转子位置的检测.在实际应用中,三级式电机在起动时采用单相交流励磁方式产生励磁电流,导致主发电机励磁电流产生较大脉动,该脉动信号的干扰使传统的定位方法难以准确估计出转子初始位置.该文通过对励磁机输出特性的分析,建立集励磁机和主发电机的一体化数学模型,提出采用傅里叶算法对响应电流数据进行分析,以获取转子初始位置的方法.实验结果表明,该文方法能够有效消除励磁机脉动干扰,实现转子位置的精确定位,同时该文算法计算量较低,易于在嵌入式系统中实现.%Along with the fast development of more electric aircrafts (MEA) and all electric aircrafts (AEA), the three-stage aviation brushless synchronous machines are widely used, which adopt the brushless structure and combine the merits of high power density and adjustable magnetic fields at the same time. According to saliency of the main generator of three-stage brushless synchronous machines, the information of rotor position is implied in performances of stator inductances due to the magnetic saturation effect. This paper studied the variation of inductances then estimated the initial rotor position of main generators by injecting modulated pulse voltage vectors. The three-stage aviation brushless synchronous machines are excited by single-phase AC during the starting period. The excitation current of the main generator contains severe pulsating components, thus the traditional methods can not
Le Doeuff, René
2013-01-01
In this book a general matrix-based approach to modeling electrical machines is promulgated. The model uses instantaneous quantities for key variables and enables the user to easily take into account associations between rotating machines and static converters (such as in variable speed drives). General equations of electromechanical energy conversion are established early in the treatment of the topic and then applied to synchronous, induction and DC machines. The primary characteristics of these machines are established for steady state behavior as well as for variable speed scenarios. I
Institute of Scientific and Technical Information of China (English)
史涔溦; 邱建琪; 金孟加; Friedrich W.Fuchs
2005-01-01
提出一种用于永磁同步电动机的基于磁链误差矢量补偿的直接转矩控制(EFVC-DTC)策略,给出了磁链误差矢量的估计算法,并将该控制策略下的稳态和动态运行性能与常规DTC进行比较.仿真及实验结果表明EFVC-DTC可以使电力开关器件工作在基本固定的频率上,磁链和转矩脉动显著减小,比常规DTC具有更优越的稳态性能,而动态转矩响应几乎与常规DTC相同.%A modified direct torque control strategy based on error flux linkage vector compensation (EFVC-DTC) for permanent magnet synchronous machines (PMSM) is presented. The theoretical background of EFVC-DTC is introduced and an algorithm to estimate the flux linkage error is proposed. The steady state and dynamic performances of EFVC-DTC have been compared with those of the conventional direct torque control (DTC). The simulation and experimental results confirm that both flux linkage and torque ripples are significantly reduced in EFVC-DTC with a fixed switching frequency while the dynamic torque response isalmost as good as the basic DTC.
Boldea, Ion
2005-01-01
This work begins with an introduction to energy resources and the main electric energy conversion solutions, along with efficiency and environmental merits and demerits. The classification and principles of various electric generator topologies are covered alongside their power ratings and main applications including constant-speed synchronous gene
Energy Technology Data Exchange (ETDEWEB)
Couaillier, V.; Rahier, G.; Fotso, P.; Greffeuille, G.
2002-07-01
A decoupling method, of flow calculation in upstream of the compressor or the blower, from the whole calculation in a turbo-machine is proposed for the forecast of the acoustic propagation in the air inlet. The interest of this approach is the capacity to slip the calculations in the non linear domain of the flow. The decoupling technic is described in details. Its validation in case of stationary and non stationary flows is presented, as an application example to a turbo-machine. (A.L.B.)
Institute of Scientific and Technical Information of China (English)
张钊; 陈涛; 周勇
2014-01-01
Aiming at the complication of introducing the control theory such as adaptive, fuzzy, neural networks, etc to the permanent magnet synchronous machine (PMSM) control system, and the required control expectation can hardly be fulfilled, the vector control system of PMSM is simulated in Matlab/Simulink. Based on the analysis of PMSM model and the control theory of space vector pulse width modulation (SVPWM), the simulation model of vector control system of PMSM is designed. The simulation result shows that the system runs stably, and gains good performance of static and dynamic response, complies with the theory analysis, provides the theoretical foundation of the design and analysis of real system, it can also be taken as reference for the system debugging.%针对将自适应、模糊、神经网络等控制理论引入永磁同步电机(permanent magnet synchronous machine， PMSM)控制系统中设计太过复杂，难以达到较理想控制效果的问题，在 Matlab/Simulink 环境下，基于矢量控制策略对 PMSM 控制系统进行建模仿真。分析 PMSM 数学模型和空间电压矢量脉宽调制(space vector pulse width modulation，SVPWM)控制原理，建立基于SVPWM的PMSM控制系统仿真模型。仿真结果表明：该系统运行平稳，具有较好的静态和动态性能，符合理论分析，能为实际系统的设计与分析提供理论依据，对工程实践中系统的调试具有一定的指导意义。
Institute of Scientific and Technical Information of China (English)
朱熀秋; 曹莉; 刁小燕; 李天博; 邹花蕾
2012-01-01
The principle of the bearingless synchronous reluctance motor (BSRM) is expatiated and the mathematics model is established. Then the least squares support vector machines (LS-SVM) system method is applied to decoupling control of the BSRM, which decouples the original system into 3 relatively independent SISO pseudo-linear subsystems. At the same time, the closed loop linear controllers are designed based on the linear system theory. The simulation system is constructed with Matlab/Simulink software. The simulation results show that this kind of control strategy can realize dynamic decoupling among electromagnetic torque and radial suspension forces of the BSRM, and the control system has excellent dynamic and static performance.%在阐述了无轴承同步磁阻电机(BSRM)工作原理的基础上,建立其数学模型,采用最小二乘支持向量机(LS-SVM)逆系统方法对其进行解耦控制,将原系统解耦成3个相对独立的伪线性子系统,并应用线性系统理论设计了闭环控制器.最后采用Matlab/Simulink构建仿真系统.仿真结果表明:此解耦控制策略能够实现无轴承同步磁阻电机电磁转矩和径向悬浮力之间的动态解耦,且系统具有良好的动、静态特性.
La compaction des sols forestiers en Wallonie
Destain, Marie-France
2014-01-01
Dans nos pays industrialisés, l’exploitation forestière fait appel à des machines de plus en plus lourdes pour assurer la vidange des coupes et le débardage des grumes. Lorsque des charges élevées sont appliquées sur des sols sensibles, une compaction du sol peut se produire entraînant une réduction de porosité, avec des conséquences néfastes sur la vitalité des peuplements. Au niveau environnemental, du fait de la compaction, l’infiltration de l’eau dans le sol est réduite, principalement...
Energy Technology Data Exchange (ETDEWEB)
Louis, J.P.
2004-07-01
Electrical actuators are present in automatized factories, in transportation systems and in many devices of the everyday life. They must be controlled in order to get an intelligent behaviour. Control systems are based on a good knowledge of actuators, electrical machines and static converters. This knowledge is condensed in models which are based on physical laws but also on hypotheses which have to be discussed (linearity, first harmonics, symmetry). These properties are used in direct models from which the inverse models are deduced and are at the origin of control algorithms. This book deals with the general concepts of the modeling of electrical machines. The analysis, simulation and synthesis of control laws is based on dynamical models used in automation (frequency and state models). The most relevant models are based on the vectorial properties of the physical models which lead to the most commonly used transformations: Clarke, Concordia, Fortescue, Lyon, Ku and Park. (J.S.)
Energy Technology Data Exchange (ETDEWEB)
Schultes, Joachim
2007-02-15
The supply system and the control system of the ATLAS pixel detector represent important building blocks of the pixel detector. Corresponding studies of the supply system, which were performed within a comprehensive test system, the so-called system test, with nearly all final components and the effects on the pixel detector are object of this thesis. A further point of this thesis is the coordination and further development of the detector-control-system software under regardment of the different partial systems. A main topic represents thereby the conceptionation of the required state machine as interface for the users and the connection to the data acquisition system.
Automated solar-cell-array assembly machine
Costogue, E. N.; Mueller, R. L.; Person, J. K.; Yasui, R. K.
1978-01-01
Continuous-feeding machine automatically bonds solar cells to printed-circuit substrate. In completed machine, cells move to test station where electrical characteristics could be checked. If performance of cell is below specifications, that cell is marked and removed. All machine functions are synchronized by electronics located within unit. It may help to lower costs in future solar-cell production.
Modulated Field Synchronous Generator for Wind Turbines
Directory of Open Access Journals (Sweden)
Petru Chioncel
2013-01-01
Full Text Available This paper presents a modern electromechanical conversion systemsolution as the modulated field synchronous generator, offering on theone hand, an output voltage with constant frequency in terms of speedvariation of the wind turbine and on the other hand an advantagepower / weight ratio due to the high frequency for which the magneticcircuit of the electric machine is sized. The mathematical model of the modulated field synchronous generator is implemented in MatLABmodeling language, highlighting the command structure on thetransistors bases of the inverter transistors, through which thefunctioning of the electric machine can be studied, especially in terms of the frequency of the delivered voltage.
A New Design of Clock Synchronization Algorithm
Directory of Open Access Journals (Sweden)
Jingmeng Liu
2014-05-01
Full Text Available The introduction of Ethernet makes the distributed network system more flexible and efficient, but it also makes nodes which are far apart from each other unable to work in the same time basis due to the long distance. This is not allowed for the high performance requirements of the system synchronization, such as high-precision multiaxis machining system. This paper presents a high-precision network clock synchronization algorithm, namely, optimal PI clock servo, which imposes a PI controller in order to compensate for the clock drift of each network node. Then a simulation platform established by the toolbox TrueTime is used to verify the stability of the algorithm and compare it with the clock synchronization algorithm of EtherCAT. The results show that the new synchronization algorithm has higher synchronization precision and faster convergence rate.
La compaction des sols agricoles en Wallonie
Destain, Marie-France
2014-01-01
Dans nos pays industrialisés, l’agriculture fait appel à des machines de plus en plus lourdes. Lorsque des charges élevées sont appliquées sur des sols sensibles, une compaction du sol peut se produire conduisant à des diminutions de rendements suite aux difficultés que rencontrent les racines pour prélever l’eau et les nutriments et à la perturbation de l’activité de la pédofaune. Au niveau environnemental, du fait de la compaction, l’infiltration de l’eau dans le sol est réduite, princip...
Energy Technology Data Exchange (ETDEWEB)
Laroche, E. [Centre National de la Recherche Scientifique (CNRS UMR), Lab. des Sciences de l' Image, de l' Informatique et de la Teledetection, 67 - Illkirch (France); Durieu, C.; Louis, J.P. [Centre National de la Recherche Scientifique (CNRS UPRESA 8029), Lab. d' Electricite, Signaux et Robotique, 94 - Cachan (France)
2002-07-01
Many parametric models of induction machines in sinusoidal mode, some of which account for saturation and iron losses, are available. These models must not only be identifiable, they must also provide for an accurate estimation of physical parameters. In this paper, parameter estimation errors due to measurement noise and model errors are analyzed. The most perturbed cases, such as those neglecting saturation or iron losses, are given special consideration herein. This study allows drawing conclusions as to the practical identifiability of the various models. Results are then used to design optimal experiments in which parameter estimation errors have been minimized. (authors)
Method for emulation of synchronous machine
DEFF Research Database (Denmark)
2011-01-01
The present invention relates to electric energy sources, such as a single wind power turbine or wind power plant, that are interfaced with the utility grid through power electronic converters. In particular, the present invention relates to specific techniques and methodologies for power electro...
Cogging torque reduction for interior permanent magnet synchronous motors
Tost Candel, Miquel
2015-01-01
Interior permanent magnet synchronous machines show a good range of behaviours, which make these kinds of machines good candidates for an electromechanical energy conversion. However, in order to improve their accuracy in their torque responses, the cogging torque and torque ripple phenomena should be mitigated to obtain better performance of the machine. In order to reduce the cogging torque and torque ripple, control techniques as well as geometric parameters of the machine have to be im...
Institute of Scientific and Technical Information of China (English)
刘朝华; 李小花; 张红强; 周少武
2015-01-01
为提高永磁同步电机(Permanent magnet synchronous machine,PMSM)系统参数辨识与状态监测效率,利用图形处理器(Graphics processing unit,GPU)并行计算与人工免疫技术相结合的研究方法,建立面向永磁同步电机系统基于GPU并行动态学习型免疫进化的参数估计与状态监测模型.为提高算法的动态跟踪性能,在抗体演化进程中,通过知识学习策略来引导算法进化过程,首先将抗体群划分为B细胞群、浆细胞群以及记忆细胞群,对处于不同进化群体中的抗体分别设计免疫综合学习策略、免疫反向学习策略和高斯学习策略,以增强抗体间的信息交互;接着,应用图形处理器并行计算技术进一步加速算法求解过程;最后,将所提算法应用于永磁同步电机系统参数辨识与状态监测中,实验表明,所提方法能同时准确地对电机的定子电阻、dq轴电感和永磁磁链等系统关键参数进行估计.依据参数变化实现对系统运行状态进行在线监测与预警.计算结果表明,GPU并行技术能大幅度提高计算效率.
Energy Technology Data Exchange (ETDEWEB)
Schellenberg, E.; Zitz, A.; Droescher, B.
1988-02-03
Apparatus for determining the position of the cutting head of a boring or mining machine, characterised by a sensor, which is oriented relative to the longitudinal axis of the drift and which may be mounted in a drift a transmitter for transmitting electromagnetic radiation in the wave-length range of 1 ..mu..m to 10 cm on the cutting head and/or on a cutting arm and a telemeter for determining the distance of at least one reference point on the cutting head and/or cutting arm from the sensor and preferably an indicator for indicating the position of the cutting head relative to a required profile to be cut.
Mapping Scrambled Korean Sentences into English Using Synchronous TAGs
Park, H S
1995-01-01
Synchronous Tree Adjoining Grammars can be used for Machine Translation. However, translating a free order language such as Korean to English is complicated. I present a mechanism to translate scrambled Korean sentences into English by combining the concepts of Multi-Component TAGs (MC-TAGs) and Synchronous TAGs (STAGs).
Permutation parity machines for neural cryptography.
Reyes, Oscar Mauricio; Zimmermann, Karl-Heinz
2010-06-01
Recently, synchronization was proved for permutation parity machines, multilayer feed-forward neural networks proposed as a binary variant of the tree parity machines. This ability was already used in the case of tree parity machines to introduce a key-exchange protocol. In this paper, a protocol based on permutation parity machines is proposed and its performance against common attacks (simple, geometric, majority and genetic) is studied.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Multi-motor vibratory transmission systems have been wide used in large vibratory machines, and four-motor linear vibratory machine is one typical equipment of them. Under non-forcible synchronization condition zero-phase synchronization of the machine is non-stationary and π-phase synchronization is stable. Under half-forcible synchronization condition in which only one motor is controlled being synchronous to another, only lag synchronization near zero-phase synchronization can be realized. Both of the characteristics have never been revealed with classical theory quantitatively. The problem is solved by means of establishing an electromechanical coupling mathematical model of the system and numerical analysis of the starting processes.
When Machines Design Machines!
DEFF Research Database (Denmark)
2011-01-01
Until recently we were the sole designers, alone in the driving seat making all the decisions. But, we have created a world of complexity way beyond human ability to understand, control, and govern. Machines now do more trades than humans on stock markets, they control our power, water, gas...... and food supplies, manage our elevators, microclimates, automobiles and transport systems, and manufacture almost everything. It should come as no surprise that machines are now designing machines. The chips that power our computers and mobile phones, the robots and commercial processing plants on which we...... depend, all are now largely designed by machines. So what of us - will be totally usurped, or are we looking at a new symbiosis with human and artificial intelligences combined to realise the best outcomes possible. In most respects we have no choice! Human abilities alone cannot solve any of the major...
Dynamical system synchronization
Luo, Albert C J
2013-01-01
Dynamical System Synchronization (DSS) meticulously presents for the first time the theory of dynamical systems synchronization based on the local singularity theory of discontinuous dynamical systems. The book details the sufficient and necessary conditions for dynamical systems synchronizations, through extensive mathematical expression. Techniques for engineering implementation of DSS are clearly presented compared with the existing techniques. This book also: Presents novel concepts and methods for dynamical system synchronization Extends beyond the Lyapunov theory for dynamical system synchronization Introduces companion and synchronization of discrete dynamical systems Includes local singularity theory for discontinuous dynamical systems Covers the invariant domains of synchronization Features more than 75 illustrations Dynamical System Synchronization is an ideal book for those interested in better understanding new concepts and methodology for dynamical system synchronization, local singularity...
Systems and methods for self-synchronized digital sampling
Samson, Jr., John R. (Inventor)
2008-01-01
Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.
Time Optimal Synchronization Procedure and Associated Feedback Loops
Angoletta, Maria Elena; CERN. Geneva. ATS Department
2016-01-01
A procedure to increase the speed of currently used synchronization loops in a synchrotron by an order of magnitude is presented. Beams dynamics constraint imposes an upper limit on excursions in stable phase angle, and the procedure presented exploits this limit to arrive in the synchronized state from an arbitrary initial state in the fastest possible way. Detailed corrector design for beam phase loop, differential frequency loop and final synchronization loop is also presented. Finally, an overview of the synchronization methods currently deployed in some other CERN’s machines is provided, together with a brief comparison with the newly proposed time-optimal algorithm.
Coil Optimization for High Temperature Superconductor Machines
DEFF Research Database (Denmark)
Mijatovic, Nenad; Jensen, Bogi Bech; Abrahamsen, Asger Bech
2011-01-01
This paper presents topology optimization of HTS racetrack coils for large HTS synchronous machines. The topology optimization is used to acquire optimal coil designs for the excitation system of 3 T HTS machines. Several tapes are evaluated and the optimization results are discussed. The optimiz...
Regulation and controlled synchronization
Huijberts, H.J.C.; Huijberts, H.J.C.; Nijmeijer, Henk; Willems, R.M.A.
1998-01-01
We investigate the problem of controlled synchronization as a regulator problem. In controlled synchronization one is given autonomous transmitter dynamics and controlled receiver dynamics. The question is to find a (output) feedback controller that achieves matching between transmitter and
Etude du parc des matériels d'épandage de matière organique en France
Mazoyer, J.
2012-01-01
/ En une vingtaine d’année, les matériels d’épandage des matières organiques sont devenus des matériels imposants, onéreux et capables d’un fort rendement de chantier. Cette évolution privilégie l’emploi de ces machines par le biais des Cuma et des entrepreneurs. Ces acteurs utilisent les machines sur plusieurs exploitations et de plus vastes surfaces. En conséquence, les ventes d’unités de machines ont baissé de façon significative, avec des modèles plus product...
Inverse anticipating chaos synchronization.
Shahverdiev, E M; Sivaprakasam, S; Shore, K A
2002-07-01
We derive conditions for achieving inverse anticipating synchronization where a driven time-delay chaotic system synchronizes to the inverse future state of the driver. The significance of inverse anticipating chaos in delineating synchronization regimes in time-delay systems is elucidated. The concept is extended to cascaded time-delay systems.
Cluster Synchronization Algorithms
Xia, Weiguo; Cao, Ming
2010-01-01
This paper presents two approaches to achieving cluster synchronization in dynamical multi-agent systems. In contrast to the widely studied synchronization behavior, where all the coupled agents converge to the same value asymptotically, in the cluster synchronization problem studied in this paper,
Aubert, Brice
2014-01-01
La mise en place d’un nouveau canal d’alimentation électrique incorporant un générateur à aimants permanents PMG (Permanent Magnet Generator) en remplacement de l’actuel canal de génération hydraulique est l’un des sujets de recherche en cours dans le secteur aéronautique. Le choix de cette solution est motivé par de nombreux avantages : réduction de masse, meilleure disponibilité du réseau hydraulique et maintenance plus aisée. Cependant, l’utilisation d’un PMG en tant que générateur électri...
Synchronization of chaotic systems.
Pecora, Louis M; Carroll, Thomas L
2015-09-01
We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators.
Synchronization of chaotic systems
Energy Technology Data Exchange (ETDEWEB)
Pecora, Louis M.; Carroll, Thomas L. [U.S. Naval Research Laboratory, Washington, District of Columbia 20375 (United States)
2015-09-15
We review some of the history and early work in the area of synchronization in chaotic systems. We start with our own discovery of the phenomenon, but go on to establish the historical timeline of this topic back to the earliest known paper. The topic of synchronization of chaotic systems has always been intriguing, since chaotic systems are known to resist synchronization because of their positive Lyapunov exponents. The convergence of the two systems to identical trajectories is a surprise. We show how people originally thought about this process and how the concept of synchronization changed over the years to a more geometric view using synchronization manifolds. We also show that building synchronizing systems leads naturally to engineering more complex systems whose constituents are chaotic, but which can be tuned to output various chaotic signals. We finally end up at a topic that is still in very active exploration today and that is synchronization of dynamical systems in networks of oscillators.
Evolution of absorption machines; Evolution des machines a absorption
Energy Technology Data Exchange (ETDEWEB)
Soide, I.; Klemsdal, E. [Gaz de France (GDF), 75 - Paris (France); Le Goff, P.; Hornut, J.M. [LSGC-ENSIC, 54 - Nancy (France)
1997-12-31
Most of todays absorption air-conditioning machineries use the lithium bromide-water pair. The most performing can operate at a 150-160 deg. C, the temperature being limited by the corrosion resistance of metals with respect to LiBr solutions. Also, there is a revival of interest for water-ammonia systems. These systems require the use of a rectification column which reduces the coefficient of performance. Higher thermal performances are reached with hydrocarbon pairs and ternary mixtures (water-methanol-LiBr etc..). This paper presents different schemes of refrigerating heat pumps based on these different systems. (J.S.)
Institute of Scientific and Technical Information of China (English)
许晓宇; 赵晓慈
2016-01-01
为减小工件装夹变形，提高薄壁件加工精度，以薄壁零件装夹变形最小化为目标函数，通过遗传算法和有限元方法相结合，提出夹紧顺序、装夹布局和夹紧力同步分析方法。用该方法对一航空薄壁零件装夹进行优化分析，优化结果与经验设计及传统分析结果进行对比，有效地降低了工件因装夹不当引起的变形，验证了夹紧顺序、夹具布局和夹紧力同步优化方法的有效性。%In order to minimize the clamping deformation and improve the machining accuracy of thin-walled parts, a synchronous optimization method of clamping sequences, fixture layout and clamping forces was presented with the objective function of minimizing the deformation and through the combination of genetic algorithm and finite element method. An aviation thin-walled work piece was optimized by this method, and compared the optimization results with the experience empirical design and the traditional analysis results. This method can effectively reduce the work piece deformation due to improper clamping and improve the machining accuracy. The result proved the veracity of the synchronous optimization method of clamping sequences, fixture layout and clamping forces.
Determination and analysis of synchronous motor's parameters
Mesņajevs, Aleksandrs; Zviedris, Andrejs
2009-01-01
In this work the parameters of synchronous machines are analyzed- direct-axis reaction Xad and quadrature-axis reaction Xaq. Methods of calculation in view of magnetic system's and its element's saturation are presented. It is shown that definition of these reactances, using as a basis a two-reaction method, is not correct and connected with work demanding chart analyzing calculations. The new approach to the qualitative and quantitative analysis of synchronous machine's operating modes which is based on consecutive use of the magnetic field's theory is offered, without it with two-reaction parameters Xad and Xaq. This approach is realized by means of a magnetic field's modeling using numerical methods with help of modern computers.
Interlanguages and synchronic models of computation
Berka, Alexander Victor
2010-01-01
A novel language system has given rise to promising alternatives to standard formal and processor network models of computation. An interstring linked with a abstract machine environment, shares sub-expressions, transfers data, and spatially allocates resources for the parallel evaluation of dataflow. Formal models called the a-Ram family are introduced, designed to support interstring programming languages (interlanguages). Distinct from dataflow, graph rewriting, and FPGA models, a-Ram instructions are bit level and execute in situ. They support sequential and parallel languages without the space/time overheads associated with the Turing Machine and l-calculus, enabling massive programs to be simulated. The devices of one a-Ram model, called the Synchronic A-Ram, are fully connected and simpler than FPGA LUT's. A compiler for an interlanguage called Space, has been developed for the Synchronic A-Ram. Space is MIMD. strictly typed, and deterministic. Barring memory allocation and compilation, modules are ref...
Directory of Open Access Journals (Sweden)
Le Berr F.
2012-08-01
Full Text Available Electrification to reduce greenhouse effect gases in transport sector is now well-known as a relevant and future solution studied intensively by the whole actors of the domain. To reach this objective, a tool for design and characterization of electric machines has been developed at IFP Energies nouvelles. This tool, called EMTool, is based on physical equations and is integrated to a complete workflow of simulation tools, as Finite Element Models or System Simulation. This tool offers the possibility to study several types of electric machine topologies: permanent magnet synchronous machine with radial or axial flux, induction machines, etc. This paper presents the main principles of design and the main equations integrated in the EMTool, the methods to evaluate electric machine performances and the validations performed on existing machine. Finally, the position of the EMTool in the simulation tool workflow and application examples are presented, notably by coupling the EMTool with advanced optimization algorithms or finite element models. Le recours à l’électrification pour réduire les émissions de gaz à effet de serre dans le domaine du transport est désormais reconnu comme une solution pertinente et d’avenir, très étudiée par l’ensemble des acteurs du domaine. Dans cet objectif, un outil d’aide au dimensionnement et à la caractérisation de machines électriques a été développé à IFP Energies nouvelles. Cet outil, appelé EMTool, est basé sur les équations physiques du domaine et est intégré à un ensemble d’outils de simulation dédiés à l’étude des groupes motopropulseurs électrifiés, comme les outils de modélisation par éléments finis ou les outils de simulation système. Il permet d’étudier plusieurs types de topologies de machines électriques : machines synchrones à aimants permanents à flux radial ou axial, machines asynchrones, etc. Ce papier présente les grands principes de
2012-01-01
Topside Variable Speed Drive (VSD) feeding a subsea load via a long cable is not a new technological challenge and many features in systems feeding asynchronous machines are well known. For a synchronous machine the situation is different as a net positive machine torque is not guaranteed. Therefor an analysis of the start sequence of such machine is of interest. In this work starting of a Permanent Magnet Synchronous Machine (PMSM) powered by a VSD via a long subsea cable have been studi...
Comportement vibratoire des roues aubagées
SAIMI, Ahmed
2013-01-01
L'innovation technologique se fait par la compréhension des phénomènes physiques complexes que l’on rencontre lors de l’exploration des différents domaines scientifiques. Parmi eux, la dynamique des rotors des machines tournantes constitue un domaine particulier de la mécanique qui a depuis longtemps intéressé autant la communauté scientifique que le monde industriel. Dans ce travail nous proposons une étude du comportement dynamique de rotor aubagé de turbomachine. Les équations du mouvement...
Fine synchronization of the muon drift tubes local trigger
Aldaya, M; Bellato, Marco; Bontenackels, Michael; Castellani, Lorenzo; Cavallo, Francesca Romana; Cerminara, Gianluca; Conti, Enrico; de la Cruz, Begona; Dal Corso, Flavio; Dallavalle, Gaetano-Marco; Fernández, C; Fernández de Troconiz, J; Fouz-Iglesias, M C; Giunta, Marina; Gonella, Franco; Guiducci, Luigi; Höpfner, K; Jimenez, Ignacio; Josa-Mutuberria, I; Marcellini, Stefano; Maron, Gaetano; Meneguzzo, Anna Teresa; Montanari, Alessandro; Navarria, Francesco; Odorici, Fabrizio; Parenti, Andrea; Passaseo, Marina; Pegoraro, Matteo; Perrotta, Andrea; Puerta, J; Reithler, Hans; Ronchese, Paolo; Rovelli, Tiziano; Ruetten, P; Sowa, Michael; Toniolo, Nicola; Travaglini, Riccardo; Vanini, Sara; Ventura, Sandro; Villanueva, C; Zanetti, Marco; Zotto, Pierluigi
2006-01-01
The CMS muon trigger, based on self-triggering arrays of drift tubes, is able to perform the identification of the muon parent bunch crossing using a rather sophisticated algorithm. The identification is unique only if the trigger chain is correctly synchronized. Some test beam time was devoted to take data useful to investigate the solutions to the problem of the synchronization of the trigger electronics with the machine clock. Possible alternatives were verified and dependence on muon track properties were studied.
全自动罗拉车系统中的同步跟随控制研究%Study on Synchronous Follow Control in Automatic Rola Machine System
Institute of Scientific and Technical Information of China (English)
王体泮
2014-01-01
为了解决目前罗拉车在线缝过程中针距不均匀、倒缝冲击大等问题，分析全自动罗拉车在缝纫过程中上、下滚轮、摆针轴及主轴的运动关系，建立控制模型，并根据这4轴同步运动数据计算跟随参数。目前，该方法已经完整地在实际项目中进行了应用，取得了很好的线缝效果。%In order to resolve the problems which are produced during line sewing such as stitch asymmetry and exquisite backstitch impacting, the paper analyses the relationships among the top idlewheel and the bottom idlewheel and the swing needle axis and the spindle, sets up the controller mode, and calculates the synchronous parameters through 4 axis synchronous motion data. Now the method is already used in fact and attains the good performance in line sewing.
Des tuiles, des toits et des couleurs
Bonnot, Thierry
2007-01-01
La Bourgogne est une des régions françaises dont l’image de marque est le plus imprégnée par la notion de tradition. Elle est présentée comme un terroir où il fait bon vivre, où la gastronomie demeure à travers les siècles une valeur de base, où les paysages sont majestueux et où la gloire passée est sans cesse rappelée par de somptueux monuments. Parmi quelques emblèmes, l’hôtel-Dieu de Beaune et ses toitures de tuiles colorées sont très souvent mobilisés pour représenter ces valeurs « tradi...
Nonlinear state space model identification of synchronous generators
Energy Technology Data Exchange (ETDEWEB)
Dehghani, M.; Nikravesh, S.K.Y. [Electrical Engineering Department, Amirkabir University of Technology, Tehran (Iran)
2008-05-15
A method for identification of a synchronous generator is suggested in this paper. The method uses the theoretical relations of machine parameters and the Prony method to find the state space model of the system. Such models are useful for controller design and stability tests. The proposed identification method is applied to a third order model of a synchronous generator. In this study, the field voltage is considered as the input and the active output power and the rotor angle are considered as the outputs of the synchronous generator. Simulation results show good accuracy of the identified model. (author)
Institute of Scientific and Technical Information of China (English)
张严心
2015-01-01
As a kind of ancillary translation tool, Machine Translation has been paid increasing attention to and received different kinds of study by a great deal of researchers and scholars for a long time. To know the definition of Machine Translation and to analyse its benefits and problems are significant for translators in order to make good use of Machine Translation, and helpful to develop and consummate Machine Translation Systems in the future.
Development of Virtual Simulation System for Remote Collaborative Surface Machining
Institute of Scientific and Technical Information of China (English)
R.S.Lee; Y.S.Lin; Y.C.Kao; C. H. She
2006-01-01
Most researches about virtual machine tool are emphasized on simulations of machine motion and machining process for single machine. In this paper, a virtual simulation system for remote collaborative surface machining is developed. The motion command of machine tool is generated by an interpolator, which can derive synchronized motion commands according to feedrate. Thus, the system can estimate the machining time. For universal assembly of five-axis virtual machine tool, it is based on the D-H notation representation and machining constraints consideration. The remote collaborative virtual manufacturing system based on the CORBA technology is proposed in this paper. It demonstrated that the developed virtual machine tool can be used to verify and simulate the machining process for the collaboration of the surface design and manufacturing team.
2017-01-01
This book provides an overview on current sustainable machining. Its chapters cover the concept in economic, social and environmental dimensions. It provides the reader with proper ways to handle several pollutants produced during the machining process. The book is useful on both undergraduate and postgraduate levels and it is of interest to all those working with manufacturing and machining technology.
Damping torque analysis of VSC-based system utilizing power synchronization control
Fu, Q.; Du, W. J.; Zheng, K. Y.; Wang, H. F.
2017-05-01
Power synchronization control is a new control strategy of VSC-HVDC for connecting a weak power system. Different from the vector control method, this control method utilizes the internal synchronization mechanism in ac systems, in principle, similar to the operation of a synchronous machine. So that the parameters of controllers in power synchronization control will change the electromechanical oscillation modes and make an impact on the transient stability of power system. This paper present a mathematical model for small-signal stability analysis of VSC station used power synchronization control and analyse the impact of the dynamic interactions by calculating the contribution of the damping torque from the power synchronization control, besides, the parameters of controllers which correspond to damping torque and synchronous torque in the power synchronization control is defined respectively. At the end of the paper, an example power system is presented to demonstrate and validate the theoretical analysis and associated conclusions are made.
Indian Academy of Sciences (India)
R E Amritkar
2008-08-01
We study the synchronization of coupled dynamical systems on networks. The dynamics is governed by a local nonlinear oscillator for each node of the network and interactions connecting different nodes via the links of the network. We consider existence and stability conditions for both single- and multi-cluster synchronization. For networks with time-varying topology we compare the synchronization properties of these networks with the corresponding time-average network. We find that if the different coupling matrices corresponding to the time-varying networks commute with each other then the stability of the synchronized state for both the time-varying and the time-average topologies are approximately the same. On the other hand, for non-commuting coupling matrices the stability of the synchronized state for the time-varying topology is in general better than the time-average topology.
Energy Technology Data Exchange (ETDEWEB)
Chabrol, D
2006-06-15
This PhD thesis contributes to the design and realization of safety-critical real-time systems on multiprocessor architectures with distributed memory. They are essential to compute systems that have to ensure complex and critical functions. This PhD thesis deals with communication media management. The communication management conditions strongly the capability of the system to fulfill the timeliness property and the dependability requirements. Our contribution includes: - The design of predictable and fault-tolerant synchronous communication protocol; - The study and the definition of the execution model to have a efficient and safe communications management; - The proposal of a method to generate automatically the communications scheduling. Our approach is based on a communication model that allows the analysis of the feasibility, before execution, of a distributed safe-critical real-time system with timeliness and safety requirements. This leads to the definition of an execution model based on a time-triggered and parallel communication management. A set of linear constraints system is generated automatically to compute the network scheduling and the network load with timeliness fulfillment. Then, the proposed communication interface is based on an advanced version of TDMA protocol which allows to use proprietary components (TTP, FlexRay) as well as standard components (Ethernet). The concepts presented in this thesis lead to the realisation and evaluation of a prototype within the framework of the OASIS project done at the CEA/List. (author)
Design of an electrochemical micromachining machine
Spieser, A; Ivanov, A.
2014-01-01
Electrochemical micromachining (μECM) is a non-conventional machining process based on the phenomenon of electrolysis. μECM became an attractive area of research due to the fact that this process does not create any defective layer after machining and that there is a growing demand for better surface integrity on different micro applications including microfluidics systems, stress-free drilled holes in automotive and aerospace manufacturing with complex shapes, etc. This work presents the des...
Applications and modelling of bulk HTSs in brushless ac machines
Energy Technology Data Exchange (ETDEWEB)
Barnes, G.J. [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom). E-mail: gary.barnes at eng.ox.ac.uk; McCulloch, M.D.; Dew-Hughes, D. [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom)
2000-06-01
The use of high temperature superconducting material in its bulk form for engineering applications is attractive due to the large power densities that can be achieved. In brushless electrical machines, there are essentially four properties that can be exploited; their hysteretic nature, their flux shielding properties, their ability to trap large flux densities and their ability to produce levitation. These properties translate to hysteresis machines, reluctance machines, trapped-field synchronous machines and linear motors respectively. Each one of these machines is addressed separately and computer simulations that reveal the current and field distributions within the machines are used to explain their operation. (author)
Applications and modelling of bulk HTSs in brushless ac machines
Barnes, G. J.; McCulloch, M. D.; Dew-Hughes, D.
2000-06-01
The use of high temperature superconducting material in its bulk form for engineering applications is attractive due to the large power densities that can be achieved. In brushless electrical machines, there are essentially four properties that can be exploited; their hysteretic nature, their flux shielding properties, their ability to trap large flux densities and their ability to produce levitation. These properties translate to hysteresis machines, reluctance machines, trapped-field synchronous machines and linear motors respectively. Each one of these machines is addressed separately and computer simulations that reveal the current and field distributions within the machines are used to explain their operation.
The Role of Synchronization in Perception-Action
Chan, Tin-Cheung; Yue, Xiaomin; Shi, Zhuanghua; Hong, Bo
Synchronization between brain areas can be taken as a sign of processes of self-organization modifying the connectivity between brain centers in such a way that they can engage effectively in different tasks. The results of an experiment investigating two issues concerning brain synchronization will be discussed here. First, does synchronization occur automatically, without effort, or through controlled processes? Second, is synchronization maintained or is it transient? In the experiment, eight participants watched two numbers presented on a screen. If the sum of these numbers was odd, participants were asked to press a button corresponding to the geometric figure following the presentation of the numbers, with the stimulus-onset asynchrony (SOA) varied between trials. In case of an even sum, no action was needed. EEG was collected with a 32-channel NeuroScan EEG machine. Analysis was conducted with multivariate autoregressive (MVAR) modeling in order to show coherence between brain areas on a spatio-temporal map. Results suggest that synchronization between perceptual or motor brain areas is automatic. When decisions have to be made, however, latency is affected by the proximity of the tasks, which shows that controlled processes are involved. Results also show that brain synchronization is transient in nature, therefore providing for synchronization patterns to be produced in sequence. It appears that the maintenance of a certain brain state and the related behavior is based on the embodiment of stimulus and task in brain synchronization.
Graybill, George
2007-01-01
Just how simple are simple machines? With our ready-to-use resource, they are simple to teach and easy to learn! Chocked full of information and activities, we begin with a look at force, motion and work, and examples of simple machines in daily life are given. With this background, we move on to different kinds of simple machines including: Levers, Inclined Planes, Wedges, Screws, Pulleys, and Wheels and Axles. An exploration of some compound machines follows, such as the can opener. Our resource is a real time-saver as all the reading passages, student activities are provided. Presented in s
Beam Synchronous Timing Systems
Peters, A
2003-01-01
For many beam diagnostics purposes beam synchronous timing systems are needed in addition to the timing systems supplied by the control systems of the different accelerators. The demands and techniques of different accelerator facilities will be discussed along the following aspects: Bunch and macro pulse synchronous timing systems Solutions for different time scales from ps to ms Coupling to the RF and control systems of the different accelerators Electronics for the beam synchronous timing systems: parameters, techniques, controlling Use of industrial products for bunch synchronous timing systems, e.g. function generators Distribution of the timing signals: electronically via cables, optically via fibres or wireless Coupling to and use of timing standards: IRIG-B, GPS, ? The participants should present and describe solutions from their facilities with some transparencies as a starting point for the discussion.
Synchronization of hyperchaotic oscillators
DEFF Research Database (Denmark)
Tamasevicius, A.; Cenys, A.; Mykolaitis, G.
1997-01-01
Synchronization of chaotic oscillators is believed to have promising applications in secure communications. Hyperchaotic systems with multiple positive Lyapunov exponents (LEs) have an advantage over common chaotic systems with only one positive LE. Three different types of hyperchaotic electronic...
Advanced synchronous luminescence system
Vo-Dinh, Tuan
1997-01-01
A method and apparatus for determining the condition of tissue or otherwise making chemical identifications includes exposing the sample to a light source, and using a synchronous luminescence system to produce a spectrum that can be analyzed for tissue condition.
Synchronization in complex networks
Energy Technology Data Exchange (ETDEWEB)
Arenas, A.; Diaz-Guilera, A.; Moreno, Y.; Zhou, C.; Kurths, J.
2007-12-12
Synchronization processes in populations of locally interacting elements are in the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understand synchronization phenomena in natural systems take now advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also overview the new emergent features coming out from the interplay between the structure and the function of the underlying pattern of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.
Machines électriques tournantes conception, dimensionnement, fonctionnement
Laporte, Bernard
2007-01-01
L'ouvrage revient aux notions fondamentales, pour introduire les machines électriques tournantes et pour élaborer les outils nécessaires à leur conception, leur dimensionnement et leur modélisation externe. Parmi les nombreux points abordés, une place importante est accordée à la conception optimale de pôles à aimants, à la conception des enroulements des machines à courant alternatif, au projet de dimensionnement des machines et aux différentes formulations en régime quelconque. Les quatre derniers chapitres sont consacrés aux principales machines électriques. Ils constituent chacun un exposé autonome, fournissant, pour la machine considérée, les équations instantanées, puis en régime établi, la mise en œuvre, les essais et les performances. C'est un ouvrage de référence pour l'enseignement des machines électriques en Master et en Ecoles d'ingénieurs. Il devrait trouver un bon accueil auprès des constructeurs et auprès de tous ceux qui, s'intéressant de près ou de loin aux mac...
Synchronizing Strategies under Partial Observability
DEFF Research Database (Denmark)
Larsen, Kim Guldstrand; Laursen, Simon; Srba, Jiri
2014-01-01
been intensively studied for systems that do not provide any information about their configurations. In order to capture more general scenarios, we extend the existing theory of synchronizing words to synchronizing strategies, and study the synchronization, short-synchronization and subset...
International Electrotechnical Commission. Geneva
1972-01-01
Applies to d.c. machines and to a.c. synchronous and induction machines. The principles can be applied to other types of machines such as rotary converters, a.c. commutator motors and single-phase induction motors for which other methods of determining losses are used.
El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI
2012-07-17
An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.
Institute of Scientific and Technical Information of China (English)
解红磊; 张为民; 杨勇
2012-01-01
In order to improve the positioning accuracy of the permanent magnet linear synchronous motors (PMLSM), a neural network is adopted to identify and compensate two types of disturbance force represented by thrust ripple and cutting force respectively in this paper. At first, the thrust ripple result from special structure of PMLSM was identified by sampling the no-load current of motor and modifying the phase difference ; then, the mod- el of thrust ripple was built and the parameters of neural network offline were optimized. Also, eliminate the error of model and compensate for the second type of disturbance force with the adaptability and nonlinear function of neural network. A complex controller with three loops and feed forward based on neural network is designed to conquer the disadvantage of pure model and makes full use of the predictable disturbance force. Simulation results verify that this controller can improve the positioning accuracy of PMLSM and its robustness is strong.%为提高永磁直线同步电机（PMLSM）的定位精度,采用神经网络技术对以推力波动和切削力为代表的两类干扰力分别进行辨识和补偿。针对PMLSM固定结构引起的推力波动,利用电机空载电流进行辨识和修正,建立推力波动模型并离线优化神经网络权系数。加工过程中,利用神经网络的自适应和非线性能力修正模型误差并补偿第二类干扰力。设计了基于神经网络的三环控制与速度、电流前馈复合控制器,克服了纯模型适应性差的缺点并充分利用可预测干扰力。仿真结果表明该控制器能够有效提高PMLSM定位精度,鲁棒性强。
Directory of Open Access Journals (Sweden)
René-Éric Dagorn
2002-05-01
Full Text Available Plusieurs numéros de Livres Hebdo et du Monde des Livres des mois de janvier-février 2002 permettent de proposer un rapide survol des grandes ventes de l’année 2001 et de quelques tendances éditoriales de l’année 2002. Quelques points ressortent particulièrement de la lecture des articles de ces deux sources : l’intérêt de la nouvelle méthode d’estimation des ventes proposée par l’institut Ipsos et Livres Hebdo , le tableau des grandes ventes en 2001 (et ...
Directory of Open Access Journals (Sweden)
Gaspard Breton
2009-04-01
Full Text Available We present a work in the framewok of machine translation from French to French Sign Language (FSL with synthesis of gestures through a virtual agent. We first give some descriptive and theoretical elements about the FSL. Then we propose a formalization of the standard part of the FSL lexicon as well as propositions concerning some morpho-syntactic phenomena. Then we present the machine translation system based on interlingua representation system "TiLT" developed at France Telecom R&D and the adaptation of its generation module to FSL. We end with the avatar technology also developed at France Telecom R&D and its FSL treatment.
La metamorphose des cypris femelles des Rhizocephales
Veillet, A.
1964-01-01
Depuis la découverte de la métamorphose des cypris de Sacculina carcini Thompson par Delage, peu de biologistes se sont intéressés au développement des Rhizocéphales. On admet aujourd'hui que tous les Cirripèdes parasites ont, comme Sacculina carcini, une forme kentrogone qui inocule le parasite au
The Machine within the Machine
Katarina Anthony
2014-01-01
Although Virtual Machines are widespread across CERN, you probably won't have heard of them unless you work for an experiment. Virtual machines - known as VMs - allow you to create a separate machine within your own, allowing you to run Linux on your Mac, or Windows on your Linux - whatever combination you need. Using a CERN Virtual Machine, a Linux analysis software runs on a Macbook. When it comes to LHC data, one of the primary issues collaborations face is the diversity of computing environments among collaborators spread across the world. What if an institute cannot run the analysis software because they use different operating systems? "That's where the CernVM project comes in," says Gerardo Ganis, PH-SFT staff member and leader of the CernVM project. "We were able to respond to experimentalists' concerns by providing a virtual machine package that could be used to run experiment software. This way, no matter what hardware they have ...
Synchronicity in predictive modelling: a new view of data assimilation
Duane, G. S.; Tribbia, J. J.; Weiss, J. B.
2006-11-01
The problem of data assimilation can be viewed as one of synchronizing two dynamical systems, one representing "truth" and the other representing "model", with a unidirectional flow of information between the two. Synchronization of truth and model defines a general view of data assimilation, as machine perception, that is reminiscent of the Jung-Pauli notion of synchronicity between matter and mind. The dynamical systems paradigm of the synchronization of a pair of loosely coupled chaotic systems is expected to be useful because quasi-2D geophysical fluid models have been shown to synchronize when only medium-scale modes are coupled. The synchronization approach is equivalent to standard approaches based on least-squares optimization, including Kalman filtering, except in highly non-linear regions of state space where observational noise links regimes with qualitatively different dynamics. The synchronization approach is used to calculate covariance inflation factors from parameters describing the bimodality of a one-dimensional system. The factors agree in overall magnitude with those used in operational practice on an ad hoc basis. The calculation is robust against the introduction of stochastic model error arising from unresolved scales.
Synchronicity in predictive modelling: a new view of data assimilation
Directory of Open Access Journals (Sweden)
G. S. Duane
2006-01-01
Full Text Available The problem of data assimilation can be viewed as one of synchronizing two dynamical systems, one representing "truth" and the other representing "model", with a unidirectional flow of information between the two. Synchronization of truth and model defines a general view of data assimilation, as machine perception, that is reminiscent of the Jung-Pauli notion of synchronicity between matter and mind. The dynamical systems paradigm of the synchronization of a pair of loosely coupled chaotic systems is expected to be useful because quasi-2D geophysical fluid models have been shown to synchronize when only medium-scale modes are coupled. The synchronization approach is equivalent to standard approaches based on least-squares optimization, including Kalman filtering, except in highly non-linear regions of state space where observational noise links regimes with qualitatively different dynamics. The synchronization approach is used to calculate covariance inflation factors from parameters describing the bimodality of a one-dimensional system. The factors agree in overall magnitude with those used in operational practice on an ad hoc basis. The calculation is robust against the introduction of stochastic model error arising from unresolved scales.
Simulation of an HTS Synchronous Superconducting Generator
DEFF Research Database (Denmark)
In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, etc. Unlike...... regular conductors, superconductors, experience high losses when exposed to AC fields. Thus, calculation of such losses is relevant for machine design to avoid quenches and increase performance. Superconducting coated conductors are well known to exhibit nonlinear resistivity, thus making the computation...... of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations. The chosen strategy for simulation is as follows: A mechanical torque signal together with an electric load is used to drive the finite...
Simulation of an HTS Synchronous Superconducting Generator
DEFF Research Database (Denmark)
Rodriguez Zermeno, Victor Manuel; Abrahamsen, Asger Bech; Mijatovic, Nenad
2012-01-01
In this work we present a simulation of a synchronous generator with superconducting rotor windings. As many other,electrical rotating machines, superconducting generators are exposed to ripple fields that could be produced from a wide variety of sources: short circuit, load change, mechanical...... torque fluctuations, etc. Unlike regular conductors, superconductors, experience high losses when exposed to AC fields. Thus, calculation of such losses is relevant for machine design to avoid quenches and increase performance. Superconducting coated conductors are well known to exhibit nonlinear...... resistivity, thus making the computation of heating losses a cumbersome task. Furthermore, the high aspect ratio of the superconducting materials involved adds a penalty in the time required to perform simulations. The chosen strategy for simulation is as follows: A mechanical torque signal together...
Korean to English Translation Using Synchronous TAGs
Egedi, D; Park, H S; Joshi, A K; Egedi, Dania; Palmer, Martha; Park, Hyun S.; Joshi, Aravind K.
1994-01-01
It is often argued that accurate machine translation requires reference to contextual knowledge for the correct treatment of linguistic phenomena such as dropped arguments and accurate lexical selection. One of the historical arguments in favor of the interlingua approach has been that, since it revolves around a deep semantic representation, it is better able to handle the types of linguistic phenomena that are seen as requiring a knowledge-based approach. In this paper we present an alternative approach, exemplified by a prototype system for machine translation of English and Korean which is implemented in Synchronous TAGs. This approach is essentially transfer based, and uses semantic feature unification for accurate lexical selection of polysemous verbs. The same semantic features, when combined with a discourse model which stores previously mentioned entities, can also be used for the recovery of topicalized arguments. In this paper we concentrate on the translation of Korean to English.
Equivalence of History and Generator Epsilon-Machines
Travers, Nicholas F
2011-01-01
Epsilon-machines are minimal, unifilar representations of stationary stochastic processes. They were originally defined in the history machine sense---as machines whose states are the equivalence classes of infinite histories with the same probability distribution over futures. In analyzing synchronization, though, an alternative generator definition was given: unifilar edge-label hidden Markov models with probabilistically distinct states. The key difference is that history epsilon-machines are defined by a process, whereas generator epsilon-machines define a process. We show here that these two definitions are equivalent.
Energy conversion loops for flux-switching PM machine analysis
E. Ilhan; T. E. Motoasca; J. J. H. Paulides; Lomonova, E.A.
2012-01-01
Induction and synchronous machines have traditionally been the first choice of automotive manufacturers for electric/hybrid vehicles. However, these conventional machines are not able anymore to meet the increasing demands for a higher energy density due to space limitation in cars. Flux-switching PM (FSPM) machines with their high energy density are very suitable to answer this demand. In this paper, the energy conversion loop technique is implemented on FSPM for the first time. The energy c...
Design and Modeling of a 3 DOF Machine
Marjan Sikandar
2014-01-01
This paper proposes an IT solution to implement a 3DOF machine by using several design patterns. A Degree of Freedom machine is a motion platform synchronized with the simulation game visually displayed. Through this research we have tried to find an optimal way to implement such a robotic machine that is supposed to be used in different virtual prototypes by industrialists. Since the development cost of an actual product often, is too high to test the initial design, many industrialists now-...
On the Optimal Selection of Electrical Machines Fans
Directory of Open Access Journals (Sweden)
Mădălin Costin
2014-09-01
Full Text Available In this paper an analytic relationship for electrical machine fan design has been developed. In the particularly case of salient poles synchronous machine (with salient poles – for electromagnetic field excitation or surface mounded permanent magnet, this approach allowed to express the fan power as a function of machine middle axe air gap. This analytic foundation developed may leads to different optimization criteria as specific active materials or costs. Numerical simulations confirm our approach.
Nondahl, T. A.; Richter, E.
1980-09-01
A design study of two types of single sided (with a passive rail) linear electric machine designs, namely homopolar linear synchronous machines (LSM's) and linear induction machines (LIM's), is described. It is assumed the machines provide tractive effort for several types of light rail vehicles and locomotives. These vehicles are wheel supported and require tractive powers ranging from 200 kW to 3735 kW and top speeds ranging from 112 km/hr to 400 km/hr. All designs are made according to specified magnetic and thermal criteria. The LSM advantages are a higher power factor, much greater restoring forces for track misalignments, and less track heating. The LIM advantages are no need to synchronize the excitation frequency precisely to vehicle speed, simpler machine construction, and a more easily anchored track structure. The relative weights of the two machine types vary with excitation frequency and speed; low frequencies and low speeds favor the LSM.
MACHINE-TRANSFORMER UNITS FOR WIND TURBINES
Directory of Open Access Journals (Sweden)
V.I. Panchenko
2016-03-01
Full Text Available Background. Electric generators of wind turbines must meet the following requirements: they must be multi-pole; to have a minimum size and weight; to be non-contact, but controlled; to ensure the maximum possible output voltage when working on the power supply system. Multipole and contactless are relatively simply realized in the synchronous generator with permanent magnet excitation and synchronous inductor generator with electromagnetic excitation; moreover the first one has a disadvantage that there is no possibility to control the output voltage, and the second one has a low magnetic leakage coefficient with the appropriate consequences. Purpose. To compare machine dimensions and weight of the transformer unit with induction generators and is an opportunity to prove their application for systems with low RMS-growth rotation. Methodology. A new design of the electric inductor machine called in technical literature as machine-transformer unit (MTU is presented. A ratio for estimated capacity determination of such units is obtained. Results. In a specific example it is shown that estimated power of MTU may exceed the same one for traditional synchronous machines at the same dimensions. The MTU design allows placement of stator coil at some distance from the rotating parts of the machine, namely, in a closed container filled with insulating liquid. This will increase capacity by means of more efficient cooling of coil, as well as to increase the output voltage of the MTU as a generator to a level of 35 kV or more. The recommendations on the certain parameters selection of the MTU stator winding are presented. The formulas for copper cost calculating on the MTU field winding and synchronous salient-pole generator are developed. In a specific example it is shown that such costs in synchronous generator exceed 2.5 times the similar ones in the MTU.
CERN. Geneva
2017-01-01
Machine learning, which builds on ideas in computer science, statistics, and optimization, focuses on developing algorithms to identify patterns and regularities in data, and using these learned patterns to make predictions on new observations. Boosted by its industrial and commercial applications, the field of machine learning is quickly evolving and expanding. Recent advances have seen great success in the realms of computer vision, natural language processing, and broadly in data science. Many of these techniques have already been applied in particle physics, for instance for particle identification, detector monitoring, and the optimization of computer resources. Modern machine learning approaches, such as deep learning, are only just beginning to be applied to the analysis of High Energy Physics data to approach more and more complex problems. These classes will review the framework behind machine learning and discuss recent developments in the field.
Measure Synchronization on Symplectic Map
Institute of Scientific and Technical Information of China (English)
CHEN Shao-Ying; XU Hai-Bo; WANG Guang-Rui; CHEN Shi-Gang
2004-01-01
Measure synchronization in coupled Hamiltonian systems is a novel synchronization phenomenon. The measure synchronization on symplectic map is observed numerically, for identical coupled systems with different parameters. We have found the properties of the characteristic frequency and the amplitude of phase locking in regular motion when the measure synchronization of coupled systems is obtained. The relations between the change of the largest Lyapunov exponent and the course of phase desynchronization are also discussed in coupled systems, some useful results are obtained. A new approach is proposed for describing the measure synchronization of coupled systems numerically,which is advantage in judging the measure synchronization, especially for the coupled systems in nonregular region.
Synchronization and Inertial Frames
Viazminsky, C P
1999-01-01
In classical mechanics, a procedure for simultaneous synchronization in all inertial frames is consistent with the Galilean transformation. However, if one attempts to achieve such a synchronization utilizing light signals, he will be facing in the first place the break down of simultaneity, and secondly, a self-contradictory transformation that has the Lorentz transformation, or its confinement to the velocity of light, as the only possible ways that resolve the contradiction. The current work constitutes a smooth transition from traditional to relativistic vision of mechanics, and therefore is quite appealing from pedagogical point of view.
ANALYSE DES MODES DE GESTION DES ENTREPRISES ...
African Journals Online (AJOL)
Administrateur
L'étude de l'art et des biens culturels en général est longtemps restée en ... en économie et management), Université d'Angers / Chef de projet chez Arterial Network. ... culturelles publiques sont apparues à partir de la fin des années 1990.
Directory of Open Access Journals (Sweden)
Stéphanie Vincent-Geslin
2012-05-01
Full Text Available Les mobilités pendulaires semblent être en augmentation en Europe depuis une dizaine d’années. Cette croissance du temps passé à se déplacer amène à remettre en question la conjecture de Zahavi et apparaît relativement inexplicable en regard du paradigme classique de l’acteur rationnel traditionnellement utilisé dans le champ des transports. Si, dans la littérature, les temps de déplacements sont principalement expliqués par le contexte résidentiel, la forme urbaine et le travail, ce cadre explicatif ne dit rien des processus de décision eux-mêmes qui amènent aux pendularités intensives.À partir d’une enquête qualitative menée auprès de pendulaires français, suisses et belges, cette contribution propose d’analyser les arbitrages et les éléments déterminants des processus de la grande pendularité. Les mobilités quotidiennes pendulaires apparaissent comme le résultat de compromis entre activité professionnelle, attachement résidentiel et choix de vie et prennent ainsi la forme de stratégies de conciliation entre vie privée et vie professionnelle. Ces mobilités spatiales permettent alors paradoxalement la préservation des ancrages résidentiels, sociaux et familiaux.Roots and wings. Long-distance commuting patterns, or how to conciliate professional and personal lifeLong-distance commuting patterns appear to be increasing in Europe over the last ten years. These raising mobility patterns lead to reappraise the Zahavi conjecture and appear largely inexplicable by the classical rational actor paradigm traditionally used in transportation research. In literature, commuting is mainly explained by residential contexts, urban forms and job. Nevertheless this theoretical frame says little about the decision-making processes themselves. Based on a qualitative survey conducted in three European countries - France, Belgium and Switzerland – among a population of high commuters, this paper proposes an analysis of
Synchronizing Hyperchaotic Circuits
DEFF Research Database (Denmark)
Tamasevicius, Arunas; Cenys, Antanas; Namajunas, Audrius
1997-01-01
Regarding possible applications to secure communications the technique of synchronizing hyperchaotic circuits with a single dynamical variable is discussed. Several specific examples including the fourth-order circuits with two positive Lyapunov exponents as well as the oscillator with a delay line...... characterized by multiple positive Lyapunov exponents are reviewd....
Synchronization of respiration
Garssen, B.
In order to study synchronization of respiration, three different videofragments were presented to 21 normal subjects. Each fragment showed a ‘therapeutic interview’ specially performed for this purpose, with a ‘patient’ breathing in a particular way. The respiration of model 1 was deep, slow and
Directory of Open Access Journals (Sweden)
Abdelli A.
2011-11-01
. Comment reduire les emissions moyennes de CO2 des vehicules particuliers a 120 g/km en 2012 et 95 g/km en 2020 comme le prevoit l’accord conclu entre la Commission Europeenne et les constructeurs europeens ? Cette question a reponses multiples preoccupe a l’heure actuelle l’ensemble du monde automobile. L’electrification des vehicules semble etre une des solutions les plus pertinentes, ce qui pousse les constructeurs a envisager des vehicules hybrides de plus en plus innovants. Cette solution, theoriquement tres interessante, complexifie encore un peu plus les groupes moto-propulseurs des vehicules, ce qui necessite l’utilisation d’outils de simulation adequats pour reduire les couts et les durees de developpement. La simulation systeme, outil deja primordial dans le processus de developpement des moteurs a combustion interne, devient alors incontournable. Pour etudier ce type d’architectures hybrides complexes, et a l’instar des modeles physiques developpes pour le moteur a combustion interne, la simulation systeme doit se doter de modeles predictifs comparables pour les machines electriques. Des leurs specifications, ces modeles doivent integrer certaines contraintes tres exigeantes sur les temps de simulation, contrainte garantissant par la suite une plus large utilisation des simulateurs, notamment pour le developpement et la validation de strategies de controle. L’objectif de ce papier est donc de presenter une methodologie generale de developpement de modeles de machines electriques, modeles ayant pour objectif final d’etre integres dans un simulateur vehicule complet. Cette methodologie met en scene differents types de modelisations (modeles elements finis, modeles de caracterisation, modele de simulation permettant un compromis temps de calcul – precision adequat. Cette methodologie a ete deployee avec succes pour la modelisation d’un moteur synchrone a aimants permanents. A l’issue du processus de modelisation, ce dernier a ete integre
A Simple and General Approach to Determination of Self and Mutual Inductances for AC machines
DEFF Research Database (Denmark)
Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen
2011-01-01
Modelling of AC electrical machines plays an important role in electrical engineering education related to electrical machine design and control. One of the fundamental requirements in AC machine modelling is to derive the self and mutual inductances, which could be position dependant. Theories...... developed so far for inductance determination are often associated with complicated machine magnetic field analysis, which exhibits a difficulty for most students. This paper describes a simple and general approach to the determination of self and mutual inductances of different types of AC machines. A new...... determination are given for a 3-phase, salient-pole synchronous machine, and an induction machine....
Energy Technology Data Exchange (ETDEWEB)
Chikkagoudar, Satish; Chatterjee, Samrat; Thomas, Dennis G.; Carroll, Thomas E.; Muller, George
2017-04-21
The absence of a robust and unified theory of cyber dynamics presents challenges and opportunities for using machine learning based data-driven approaches to further the understanding of the behavior of such complex systems. Analysts can also use machine learning approaches to gain operational insights. In order to be operationally beneficial, cybersecurity machine learning based models need to have the ability to: (1) represent a real-world system, (2) infer system properties, and (3) learn and adapt based on expert knowledge and observations. Probabilistic models and Probabilistic graphical models provide these necessary properties and are further explored in this chapter. Bayesian Networks and Hidden Markov Models are introduced as an example of a widely used data driven classification/modeling strategy.
Directory of Open Access Journals (Sweden)
Helen Chang
2011-08-01
Full Text Available In spite of many significant differences between high-income and developing country partners in the North American Free Trade Agreement (NAFTA, business cycle synchronization has followed increased trade integration in the post-NAFTA period. There is also some preliminary support for some convergence between Dominican Republic-Central American Free Trade Agreement (CAFTA-DR economies post-CAFTA-DR, although it is too soon to reach any significant conclusions. Macroeconomic synchronization has important implications for policy making because it indicates the need for and benefits from policy coordination. Policy coordination with high-income partners may benefit developing country partners by reducing macroeconomic volatility and increase stability, when macroeconomic variability is due to common shocks and not country-specific shocks. Idiosyncratic volatility would require monetary and fiscal policy autonomy rather than coordination. Examining policy coordination between NAFTA states and between CAFTA-DR members, I find little evidence for policy coordination before and after implementation of the FTA. For the developing partners in NAFTA and CAFTA-DR, even as trade integration shrinks the available policy options for member states, the costs of losing policy autonomy largely outweigh the benefits of coordination because of the idiosyncratic macroeconomic variability of the developing partners.A pesar de las numerosas diferencias significativas que existen entre los países de renta alta y los países en desarrollo miembros del Tratado de Libre Comercio de América del Norte (TLCAN, la sincronización de los ciclos económicos ha seguido a una integración comercial en aumento desde la entrada en vigor del TLCAN. Asimismo, existen pruebas de que algunas economías del CAFTA-DR (Tratado de Libre Comercio entre República Dominicana, Centroamérica y Estados Unidos muestran también una cierta convergencia de los ciclos económicos pese a que es
Energy Technology Data Exchange (ETDEWEB)
Kameier, F. (TU Berlin (Germany). Hermann-Foettinger Inst.); Neise, W. (DLR, Berlin (Germany). Abt. Turbulenzforschung)
1994-08-01
The article describes a design feature that can reduce the sound emission of axial flow machines by up to 11 dB (A) (specific sound level), whilst improving the efficiency by seven percentage points. This improvement can be carried out on equipment that is already in use, as well as on new design. The gap between the rotating blades and the fixed housing, causes losses and an increased sound emission in axial flow machines. The aerodynamic and acoustic effects of a variation in the gap has been extensively examined on a model of a high-pressure axial blower. The widest gap (0.5% of the impeller diameter) has been retroactively improved in design so that a reduction in the negative effect of the gap occurs whilst retaining its nominal size. The diameter of the impeller as well as that of the housing remain unchanged. The gap modification, for which a patent has been applied for, has the equivalent effect of halving the gap width. (orig.)
Synchronously deployable truss structure
Bush, H. G. (Inventor); Mikulas, M., Jr. (Inventor); Wallsom, E. (Inventor)
1986-01-01
A collapsible-expandable truss structure, including first and second spaced surface truss layers having an attached core layer is described. The surface truss layers are composed of a plurality of linear struts arranged in multiple triangular configurations. Each linear strut is hinged at the center and hinge connected at each end to a nodular joint. A passive spring serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. A damper controls the rate of spring expansion for the synchronized deployment of the truss as the folded configuration is released for deployment by the restrain belts. The truss is synchronously extended under the control of motor driven spools.
Synchronization of micromasers
Davis-Tilley, C.; Armour, A. D.
2016-12-01
We investigate synchronization effects in quantum self-sustained oscillators theoretically using the micromaser as a model system. We use the probability distribution for the relative phase as a tool for quantifying the emergence of preferred phases when two micromasers are coupled together. Using perturbation theory, we show that the behavior of the phase distribution is strongly dependent on exactly how the oscillators are coupled. In the quantum regime where photon occupation numbers are low we find that, although synchronization effects are rather weak, they are nevertheless significantly stronger than expected from a semiclassical description of the phase dynamics. We also compare the behavior of the phase distribution with the mutual information of the two oscillators and show that they can behave in rather different ways.
DEFF Research Database (Denmark)
De Chiffre, Leonardo
This document is used in connection with a laboratory exercise of 3 hours duration as a part of the course GEOMETRICAL METROLOGY AND MACHINE TESTING. The exercise includes a series of tests carried out by the student on a conventional and a numerically controled lathe, respectively. This document...
DEFF Research Database (Denmark)
Petersson, Dag; Dahlgren, Anna; Vestberg, Nina Lager
to the enterprises of the medium. This is the subject of Representational Machines: How photography enlists the workings of institutional technologies in search of establishing new iconic and social spaces. Together, the contributions to this edited volume span historical epochs, social environments, technological...
Commande adaptive d'une machine asynchrone
I. Slama-Belkhodja; De Fornel, B.
1996-01-01
Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation e...
Introduction to the Report "Interlanguages and Synchronic Models of Computation."
Berka, Alexander Victor
2010-01-01
A novel language system has given rise to promising alternatives to standard formal and processor network models of computation. An interstring linked with a abstract machine environment, shares sub-expressions, transfers data, and spatially allocates resources for the parallel evaluation of dataflow. Formal models called the a-Ram family are introduced, designed to support interstring programming languages (interlanguages). Distinct from dataflow, graph rewriting, and FPGA models, a-Ram instructions are bit level and execute in situ. They support sequential and parallel languages without the space/time overheads associated with the Turing Machine and l-calculus, enabling massive programs to be simulated. The devices of one a-Ram model, called the Synchronic A-Ram, are fully connected and simpler than FPGA LUT's. A compiler for an interlanguage called Space, has been developed for the Synchronic A-Ram. Space is MIMD. strictly typed, and deterministic. Barring memory allocation and compilation, modules are ref...
Successful synchronization of the LHC's clockwise beam transfer system
2008-01-01
LHC synchronization test successful The synchronization of the LHC's clockwise beam transfer system and the rest of CERN's accelerator chain was successfully achieved last weekend. Tests began on Friday 8 August when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered about 3 kilometres around the LHC itself on the first attempt. On Saturday, the test was repeated several times to optimize the transfer before the operations group handed the machine back for hardware commissioning to resume on Sunday. The anti-clockwise synchronization systems will be tested over the weekend of 22 August.
Usinage des Composites par Jet d'eau Abrasif
Cénac, François; Collombet, Francis; Zitoune, Rédouane; Déléris, Michel
2011-01-01
International audience; Le protocole expérimental de fraisage par jet d'eau abrasif obtenu sur aluminium est adapté aux matériaux composites. On met en exergue deux différences majeures liées à l'effet du JEA entre les composites et l'aluminium que sont l'usinabilité et les variabilités. L'usinabilité des matériaux composites étant plus grande que celle de l'aluminium pour le JEA, on propose des plages de paramètres différentes pour les composites, du fait des limitations des machines standar...
Speiser, Bernhard; Tamm, Lucius; Maurer, Veronika; Berner, Alfred; Schneider, Claudia; Chevillat, Véronique
2015-01-01
La liste des intrants contient tous les produits phytosanitaires, les engrais, les substrats du commerce, les produits de lutte contre les mouches des étables, les agents d'ensilage, les aliments minéraux et complémentaires, les produits pour la désinfection des stabulations et les produits contre les maladies des abeilles autorisés pour l'agriculture biologique. Cette liste est contraignante pour les producteurs de Bio Suisse. Sur les fermes Bio Suisse, seuls les produits mentionnés sont aut...
Successful attack on permutation-parity-machine-based neural cryptography.
Seoane, Luís F; Ruttor, Andreas
2012-02-01
An algorithm is presented which implements a probabilistic attack on the key-exchange protocol based on permutation parity machines. Instead of imitating the synchronization of the communicating partners, the strategy consists of a Monte Carlo method to sample the space of possible weights during inner rounds and an analytic approach to convey the extracted information from one outer round to the next one. The results show that the protocol under attack fails to synchronize faster than an eavesdropper using this algorithm.
Adding machine and calculating machine
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
In 1642 the French mathematician Blaise Pascal(1623-1662) invented a machine;.that could add and subtract. It had.wheels that each had: 1 to 10 marked off along its circumference. When the wheel at the right, representing units, made one complete circle, it engaged the wheel to its left, represents tens, and moved it forward one notch.
Determination of a synchronous generator characteristics via Finite Element Analysis
Directory of Open Access Journals (Sweden)
Kolondzovski Zlatko
2005-01-01
Full Text Available In the paper a determination of characteristics of a small salient pole synchronous generator (SG is presented. Machine characteristics are determined via Finite Element Analysis (FEA and for that purpose is used the software package FEMM Version 3.3. After performing their calculation and analysis, one can conclude that most of the characteristics presented in this paper can be obtained only by using the Finite Element Method (FEM.
Torque ripple reduction in electric machines
Energy Technology Data Exchange (ETDEWEB)
Reddy, Patel Bhageerath; Huh, Kum-Kang; El-Refaie, Ayman Mohamed Fawzi; Galioto, Steven Joseph
2017-08-22
An electric machine, such as an Internal Permanent magnet or Synchronous Reluctance machine, having X phases, that includes a stator assembly, having M slots, with a stator core and stator teeth, that is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface that defines a cavity; and a rotor assembly, having N poles, disposed within the cavity which is configured to rotate about the longitudinal axis, wherein the rotor assembly includes a shaft, a rotor core located circumferentially around the shaft. The machine is configured such that a value k=M/(X*N) wherein k is a non-integer greater than about 1.3. The electric machine may alternatively, or additionally, include a non-uniformed gap between the exterior surface of the rotor spokes and the interior stator surface of the stator.
Permanent Magnet Synchronous Condenser with Solid State Excitation
Energy Technology Data Exchange (ETDEWEB)
Hsu, Ping; Muljadi, Eduard; Wu, Ziping; Gao, Wenzhong
2015-10-05
A synchronous condenser consists of a free-spinning wound-field synchronous generator and a field excitation controller. In this paper, we propose a synchronous generator that employs a permanent magnet synchronous generator (PMSG) instead of a wound-field machine. PMSGs have the advantages of higher efficiency and reliability. In the proposed configuration, the reactive power control is achieved by a voltage source converter connected in series with the PMSG and the grid. The converter varies the phase voltage of the PMSG so as to create the same effect of over or under excitation in a wound-field machine. The converter output voltage level controls the amount and the direction of the produced reactive power and the voltage's phase is kept in-phase with the grid voltage except a slight phase can be introduced so that some power can be drawn from the grid for maintaining the DC bus voltage level of the converter. Since the output voltage of the converter is only a fraction of the line voltage, its VA rating is only a fraction of the rating of the PMSG. The proposed scheme is shown to be effective by computer simulation.
The transient ladder synchronization of chaotic systems
Energy Technology Data Exchange (ETDEWEB)
Chen, H.-K. [Department of Industrial Engineering and Management, Hsiuping Institute of Technology, No. 11, Gungye Rd., Dali City, Taichung, Taiwan (China)]. E-mail: kanechen@giga.net.tw; Sheu, L.-J. [Department of Mechanical Engineering, Chung Hua University, Hsinchu, Taiwan (China)]. E-mail: ljsheu@chu.edu.tw
2006-07-03
A new type for chaotically synchronizing systems, transient ladder chaos synchronization, is proposed in this Letter. For some physical systems, chaotic synchronization is possible in only some of the variables. It is shown that, for the non-synchronizing variable, synchronization up to a constant difference for t{sub 1}=
Amos, Martyn
2014-01-01
Silicon chips are out. Today's scientists are using real, wet, squishy, living biology to build the next generation of computers. Cells, gels and DNA strands are the 'wetware' of the twenty-first century. Much smaller and more intelligent, these organic computers open up revolutionary possibilities. Tracing the history of computing and revealing a brave new world to come, Genesis Machines describes how this new technology will change the way we think not just about computers - but about life itself.
Energy Technology Data Exchange (ETDEWEB)
Fenoglietto, P.; Ailleres, N.; Simeon, S.; Dubois, J.B.; Azria, D. [CRLC Val d' Aurelle, 34 - Montpellier (France)
2010-10-15
An institution possesses three accelerators which have been identically parameterized as far as energies and collimators are concerned, to deliver equivalent intensity-modulated conformational radiotherapy. The RapidArc methodology has been implemented on a first machine, and then on a second one. The authors report tests performed to check whether a treatment could be optimized on a specific accelerator, and then performed on another one. Six patients suffering from ORL cancers have been selected. Dose computation and optimization has been performed with Eclipse. Half of treatments have been optimized on one accelerator, and the other half on the other one. According to the comparison between measured and computed doses, it appears that, in an institution possessing twin machines, patients may pass from one accelerator to the other without performing a new dosimetry. Short communication
Energy Technology Data Exchange (ETDEWEB)
Segura Ozuna, Victor Octavio; Hernandez Rodriguez, Isaura Victoria; Alcaide Godinez, Indira Xochiquetzal; Garduno Ramirez, Raul; Montero Cervantes, Julio Cesar [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Ruiz Rodriguez, Genaro; Martinez Torres; Ricardo [CFE-LAPEM, Irapuato, Guanajuato (Mexico)
2012-07-01
This paper introduces a characterization of the behavior of the speed and voltage control systems of a special purpose synchronous machine (GCC) based on measuring and monitoring physical signals, and recording of the sampled waveforms. Basically, the GCC supplies the energy to perform high-power short-circuits tests to certify electrical equipment and components, as required by the Comision Federal de Electricidad (CFE) in Mexico. The GCC operates alternately as motor and generator. With the GCC operating as motor, speed control during startup, acceleration, re-acceleration and braking is carried out by a static frequency converter (SFC). Complementary, the voltage controller manipulates excitation power to control terminal voltage when the GCC operates as generator and regulates excitation current when the GCC operates as motor. Compared to conventional voltage regulation systems, which must go off in case of short-circuit, the GCC voltage regulator must keep controlling field excitation to maintain the required line current and terminal voltage during short-circuit tests. Monitoring of physical signals was carried out with a portable data acquisition system based on SCXI and PXI digital platforms. A total of 78 signals were monitored with a 6 kHz sampling rate that was enough to obtain detailed signal waveforms. Data captured was processed and plotted for analysis. The signal graphs show the current real behavior of both, the voltage control system and the speed control system, and constitute a precise characterization of their behavior. [Spanish] Este documento presenta una caracterizacion del comportamiento de los sistemas de control de velocidad y voltaje de una maquina sincrona de proposito especial (GCC) basada en la medicion y monitoreo de senales fisicas, asi como en el registro de las formas de onda muestreadas. Basicamente, la GCC suministra la energia para efectuar pruebas de corto circuito de alta potencia para certificar equipo y componentes
Institute of Scientific and Technical Information of China (English)
刘英培; 栗然; 梁海平
2014-01-01
Traditional PI regulator has some defects. Direct torque control (DTC) for permanent magnet synchronous motor (PMSM) based on active-disturbance rejection control (ADRC) optimized by least squares support vector machines (LSSVM) method was proposed in this paper. The speed regulator based on ADRC was designed with the inputs of given speed and real speed and the output of given electromagnet torque. The Gaussian radial basis kernel function was chosen in the model. The realization of the LSSVM regression model embedded in ADRC regulator was analyzed in-depth and detailed, which optimized the ADRC regulator. The ADRC observation precision and dynamic response are improved. The effect of motor parameters and load disturbances on the system is significantly reduced. The anti-interference ability of the system is further improved. Simulation and experiment results have verified the feasibility and effectiveness of this method.%针对传统PI调节器的缺陷，提出一种基于最小二乘支持向量机(least squares support vector machine，LSSVM)优化自抗扰控制器(active-disturbance rejection control， ADRC)的永磁同步电机直接转矩控制方法。以给定转速和实际转速作为输入信号，以给定电磁转矩作为输出信号，设计了 ADRC 速度调节器；在此基础上，在回归模型中选取高斯径向基核函数，深入分析了将LSSVM回归模型有效嵌入ADRC调节器的实现方法，实现对ADRC控制器的优化，以提高 ADRC 观测精度及系统动态响应速度，很大程度上降低了电机参数变化和负载扰动对系统的影响，进一步改善了系统的抗干扰能力。仿真和实验结果验证了该方法的可行性和有效性。
Remote Synchronization in Complex Networks
Gambuzza, Lucia Valentina; Fiasconaro, Alessandro; Fortuna, Luigi; Gómez-Gardeñes, Jesús; Frasca, Mattia
2013-01-01
We show the existence of a novel dynamical state called remote synchronization in general networks of coupled oscillators. This state is characterized by the synchronization of pairs of nodes that are not directly connected via a physical link or any sequence of synchronized nodes. This phenomenon cannot be observed in networks of phase oscillators as its underlying mechanism is the modulation of the amplitude of those intermediary nodes between the remotely synchronized units. Our findings thus show the ubiquity and robustness of these states and bridge the gap from their recent observation in simple toy graphs to complex networks.
PARTIAL SYNCHRONIZATION BETWEEN DIFFERENT SYSTEMS
Institute of Scientific and Technical Information of China (English)
CHEN Jun; LIU Zeng-rong
2005-01-01
A new method for partial synchronization between different systems was obtained. The definition of partial synchronization under which the problem works is given. The stability of the method is analyzed by the Liapunov function method and the condition of choosing the control term is derived. The reliability of this method is proved by some numerical examples, in which the dynamical behaviors of the synchronized systems are observed and it is found that whatever state the response system is partial synchronization can be always achieved by adding some proper control term.
Louisot, Jean-Paul
2009-01-01
Depuis le début du lie siècle, la gestion des risques connaît une véritable révolution culturelle. Jusqu'alors fonction technique, centrée autour de l'achat de couverture d'assurances, elle est devenue une discipline managériale et transversale : une valise d'instruments que chaque manager doit connaître et appliquer quels que soient son domaine de compétence et ses missions au sein de l'organisation. En effet, la gestion des risques est une culture qui doit être assimilée par chacun des acteurs. C'est précisément l'ambition des 101 questions rassemblées dans cet ouvrage : apporter à chaque manager d'entreprise, de collectivité, d'établissement de santé..., des réponses claires au " pourquoi " et au " comment " : Comment identifier les risques ? Comment analyser les risques ? Quels sont les objectifs de la gestion des risques ? Une carte des risques pour quoi faire ? Pourquoi faut-il financer les risques ? Les entreprises ont-elles des responsabilités pénales ? En quoi consiste la gestion...
Simulation and experimental results of hybrid electric machine with a novel flux control strategy
Directory of Open Access Journals (Sweden)
Paplicki Piotr
2015-03-01
Full Text Available The paper presents selected simulation and experimental results of a hybrid ECPMS-machine (Electric Controlled Permanent Magnet Synchronous Machine. This permanent magnets (PMs excited machine offers an extended magnetic field control capability which makes it suitable for battery electric vehicle (BEV drives. Rotor, stator and the additional direct current control coil of the machine are analyzed in detail. The control system and strategy, the diagram of power supply system and an equivalent circuit model of the ECPMS-machine are presented. Influence of the additional excitation on the performance parameters of the machine, such as: torque, efficiency, speed limits and back-EMF have also been discussed.
Simulating Turing machines on Maurer machines
Bergstra, J.A.; Middelburg, C.A.
2008-01-01
In a previous paper, we used Maurer machines to model and analyse micro-architectures. In the current paper, we investigate the connections between Turing machines and Maurer machines with the purpose to gain an insight into computability issues relating to Maurer machines. We introduce ways to
Le dialogisme intertextuel des contes des Grimm
2012-01-01
« Le caractère le plus important de l’énoncé, ou en tous cas le plus ignoré, est son dialogisme, c’est-à-dire sa dimension intertextuelle », constate Todorov en référence à la conception dialogique du langage proposée par Bakthine. Cet article introductif postule que ce constat s’applique aussi aux contes des Grimm. En partant des recherches déjà menées sur Apulée, Straporola, Basile, Perrault, La Fontaine et Lhéritier, il présente des concepts (réponse intertextuelle, reconfiguration génériq...
Institute of Scientific and Technical Information of China (English)
骆光照; 张围围; 杨南方; 马鹏; 刘卫国
2012-01-01
A flux linkage compensation field oriented control (FOC) method was proposed to suppress the speed and torque ripples of a hrusbless wound-fleld synchronous motor in its starting process. The starting process was analyzed and the model of wound-field synchronous electric machine was established. The change of field current of the electric machine was described mathematically for simplified exciter and rotate rectifier. Based on the traditional field control, the flux linkage compensation was introduced in d-axis current to counteract the flux ripple. Some simulation and preliminary experiments were implemented. The results show that the proposed method is feasible and effective.
Formation des formateurs en ligne : obstacles, rôles et compétences
Directory of Open Access Journals (Sweden)
Louise Sauvé
2004-01-01
Full Text Available L’adoption d’une technologie de l’information et de la communication (TIC pour la formation ne peut se faire sans changement dans l’organisation. Ces changements touchent les formateurs, hommes et femmes, qui ont une histoire professionnelle, une mentalité, des pratiques qui se sont construites au cours des années et dans un contexte précis de travail. Or les changements technologiques peuvent déstabiliser la vie professionnelle des formateurs. Il est donc essentiel de gérer ce changement, car le succès des projets d’introduction des TIC dans la formation n’est plus fonction de la puissance des technologies, mais plutôt de la capacité des formateurs à exploiter leur potentiel afin de changer et d’améliorer l’efficience du processus d’apprentissage. C’est dans un contexte d’implantation d’une formation des formateurs en ligne que se situe cet article qui aborde les questions suivantes : quels sont les obstacles au changement par rapport à l’adoption des TIC dans le milieu de la formation? Quels sont les principaux rôles d’un formateur en ligne (ou e-formateur? Quelles sont les compétences générales que les formateurs doivent développer pour soutenir les apprenants dans un contexte de formation en ligne (synchrone et asynchrone?
FPGA based fast synchronous serial multi-wire links synchronization
Pozniak, Krzysztof T.
2013-10-01
The paper debates synchronization method of multi-wire, serial link of constant latency, by means of pseudo-random numbers generators. The solution was designed for various families of FPGA circuits. There were debated synchronization algorithm and functional structure of parameterized transmitter and receiver modules. The modules were realized in VHDL language in a behavioral form.
Environmentally Friendly Machining
Dixit, U S; Davim, J Paulo
2012-01-01
Environment-Friendly Machining provides an in-depth overview of environmentally-friendly machining processes, covering numerous different types of machining in order to identify which practice is the most environmentally sustainable. The book discusses three systems at length: machining with minimal cutting fluid, air-cooled machining and dry machining. Also covered is a way to conserve energy during machining processes, along with useful data and detailed descriptions for developing and utilizing the most efficient modern machining tools. Researchers and engineers looking for sustainable machining solutions will find Environment-Friendly Machining to be a useful volume.
DEFF Research Database (Denmark)
Ni, Ronggang; Xu, Dianguo; Wang, Gaolin
2016-01-01
the application field. The system electromechanical model during switching is deduced and analyzed numerically to verify the stability under grid drive. For the control strategy, model-based sliding-mode observer is adopted during soft start for low-cost position sensorless drive, and two digital phase lock loops...
Knight, K; Knight, Kevin; Graehl, Jonathan
1997-01-01
It is challenging to translate names and technical terms across languages with different alphabets and sound inventories. These items are commonly transliterated, i.e., replaced with approximate phonetic equivalents. For example, "computer" in English comes out as "konpyuutaa" in Japanese. Translating such items from Japanese back to English is even more challenging, and of practical interest, as transliterated items make up the bulk of text phrases not found in bilingual dictionaries. We describe and evaluate a method for performing backwards transliterations by machine. This method uses a generative model, incorporating several distinct stages in the transliteration process.
Global Exponential Projective Synchronization and Lag Synchronization of Hyperchaotic Lü System
Institute of Scientific and Technical Information of China (English)
ZHANG Qun-Jiao; LU Jun-An; JIA Zhen
2009-01-01
This paper investigates the projective synchronization and lag synchronization of a new hyperchaotic system[Physica A 364 (2006) 103]. On the basis of Lyapunov stability theory, two novel nonlinear controllers are respectively designed to guarantee the global exponential projective synchronization (including complete synchronization and anti-synchronization) and lag synchronization. Finally, numerical simulations are given to show the effectiveness of the main results.
Schmidt, R
2014-01-01
The protection of accelerator equipment is as old as accelerator technology and was for many years related to high-power equipment. Examples are the protection of powering equipment from overheating (magnets, power converters, high-current cables), of superconducting magnets from damage after a quench and of klystrons. The protection of equipment from beam accidents is more recent. It is related to the increasing beam power of high-power proton accelerators such as ISIS, SNS, ESS and the PSI cyclotron, to the emission of synchrotron light by electron–positron accelerators and FELs, and to the increase of energy stored in the beam (in particular for hadron colliders such as LHC). Designing a machine protection system requires an excellent understanding of accelerator physics and operation to anticipate possible failures that could lead to damage. Machine protection includes beam and equipment monitoring, a system to safely stop beam operation (e.g. dumping the beam or stopping the beam at low energy) and an ...
Digital synchronization and communication techniques
Lindsey, William C.
1992-01-01
Information on digital synchronization and communication techniques is given in viewgraph form. Topics covered include phase shift keying, modems, characteristics of open loop digital synchronizers, an open loop phase and frequency estimator, and a digital receiver structure using an open loop estimator in a decision directed architecture.
Order release in synchronous manufacturing
Riezebos, J.
2010-01-01
Synchronous manufacturing aims at achieving the benefits of intermittent production lines in production situations that operate without lines. Benefits such as short and constant throughput times and predictable capacity loading can be acquired through an appropriate design of the synchronous manufa
Biologically Inspired Intercellular Slot Synchronization
Directory of Open Access Journals (Sweden)
Alexander Tyrrell
2009-01-01
Full Text Available The present article develops a decentralized interbase station slot synchronization algorithm suitable for cellular mobile communication systems. The proposed cellular firefly synchronization (CelFSync algorithm is derived from the theory of pulse-coupled oscillators, common to describe synchronization phenomena in biological systems, such as the spontaneous synchronization of fireflies. In order to maintain synchronization among base stations (BSs, even when there is no direct link between adjacent BSs, some selected user terminals (UTs participate in the network synchronization process. Synchronization emerges by exchanging two distinct synchronization words, one transmitted by BSs and the other by active UTs, without any a priori assumption on the initial timing misalignments of BSs and UTs. In large-scale networks with inter-BS site distances up to a few kilometers, propagation delays severely affect the attainable timing accuracy of CelFSync. We show that by an appropriate combination of CelFSync with the timing advance procedure, which aligns uplink transmission of UTs to arrive simultaneously at the BS, a timing accuracy within a fraction of the inter-BS propagation delay is retained.
Exploiting Schemas in Data Synchronization
DEFF Research Database (Denmark)
Foster, J. Nathan; Greenwald, Michael B.; Kirkegaard, Christian
2005-01-01
Increased reliance on optimistic data replication has led to burgeoning interest in tools and frameworks for disconnected updates to replicated data.We have implemented a generic synchronization framework, called HARMONY, that can be used to build state-based synchronizers for a wide variety of t...
Benefits of Synchronous Online Courses
Moser, Scott; Smith, Phil
2015-01-01
Most online courses are offered as "asynchronous" courses and have no real-time contact with students. The Synchronous online alternative provides normal scheduled class time and allows students to login to a virtual online classroom with the instructor. We provide an overview of two different platforms for hosting synchronous classes…
Network algebra for synchronous dataflow
Bergstra, J.A.; Middelburg, C.A.; Ștefánescu, G.
2013-01-01
We develop an algebraic theory of synchronous dataflow networks. First, a basic algebraic theory of networks, called BNA (Basic Network Algebra), is introduced. This theory captures the basic algebraic properties of networks. For synchronous dataflow networks, it is subsequently extended with
Order release in synchronous manufacturing
Riezebos, J.
2010-01-01
Synchronous manufacturing aims at achieving the benefits of intermittent production lines in production situations that operate without lines. Benefits such as short and constant throughput times and predictable capacity loading can be acquired through an appropriate design of the synchronous manufa
Synchronization dynamics of two different dynamical systems
Energy Technology Data Exchange (ETDEWEB)
Luo, Albert C.J., E-mail: aluo@siue.edu [Department of Mechanical and Industrial Engineering, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1805 (United States); Min Fuhong [Department of Mechanical and Industrial Engineering, Southern Illinois University Edwardsville, Edwardsville, IL 62026-1805 (United States)
2011-06-15
Highlights: > Synchronization dynamics of two distinct dynamical systems. > Synchronization, de-synchronization and instantaneous synchronization. > A controlled pendulum synchronizing with the Duffing oscillator. > Synchronization invariant set. > Synchronization parameter map. - Abstract: In this paper, synchronization dynamics of two different dynamical systems is investigated through the theory of discontinuous dynamical systems. The necessary and sufficient conditions for the synchronization, de-synchronization and instantaneous synchronization (penetration or grazing) are presented. Using such a synchronization theory, the synchronization of a controlled pendulum with the Duffing oscillator is systematically discussed as a sampled problem, and the corresponding analytical conditions for the synchronization are presented. The synchronization parameter study is carried out for a better understanding of synchronization characteristics of the controlled pendulum and the Duffing oscillator. Finally, the partial and full synchronizations of the controlled pendulum with periodic and chaotic motions are presented to illustrate the analytical conditions. The synchronization of the Duffing oscillator and pendulum are investigated in order to show the usefulness and efficiency of the methodology in this paper. The synchronization invariant domain is obtained. The technique presented in this paper should have a wide spectrum of applications in engineering. For example, this technique can be applied to the maneuvering target tracking, and the others.
Torque Characteristics of Saturated Permanent-Magnet Synchronous Motors
Takahashi, Akeshi; Kikuchi, Satoshi; Wakui, Shinichi; Mikami, Hiroyuki; Ide, Kazumasa; Shima, Kazuo
The evaluation of torque characteristics in a saturated magnetic field for permanent-magnet (PM) synchronous motors is presented. The torque saturation characteristics of non-salient and salient pole machines are investigated by finite element analysis and measurement. Thus, it is found that the torque saturation originates in the magnetic saturation in both the stator teeth, which are located on the leading position toward the direct axis, and in the stator back yoke, which is located on the lagging position toward the direct axis. This mechanism can also explain the reason for the significant torque saturation in the salient-pole machine; the higher inductance of the quadrature axis of the salient-pole machine causes a significant magnetic saturation in the stator back yoke. Therefore, less saliency or a wider back yoke can improve the torque saturation.
Berthier, Serge
2010-01-01
La photonique est déjà présente dans notre vie quotidienne, et on attend maintenant que la manipulation des photons permette aussi le traitement logique des informations. Cependant, l’élément de base qui permet cette manipulation de la lumière, le cristal photonique, est d’une réalisation complexe et mal contrôlée. Dans la course à la maîtrise de la lumière, les structures photoniques naturelles ont beaucoup à nous apprendre. C’est ce que nous montre Serge Berthier qui étudie dans ce livre la structure des écailles des Morphos. Tenant compte de l’essor récent des approches biomimétiques, il présente de manière détaillée plus de dix-huit techniques expérimentales utilisées pour ses analyses, ainsi que les diverses approches théoriques développées pour la modélisation de structures multi-échelles complexes. Première étude quasi-exhaustive des structures fines d’un genre et des propriétés optiques ainsi que colorimétriques générées, ce livre fournit aux entomologiste...
Droit des organisations internationales
Sorel, Jean-Marc; Ndior, Valère
2013-01-01
Cet ouvrage collectif offre aux enseignants et chercheurs en droit international, aux praticiens et aux étudiants, une analyse actualisée du droit des organisations internationales. Il dresse en cinq parties un tableau, illustré par des exemples variés, des problématiques que soulève le phénomène polymorphe d institutionnalisation de la société internationale. La première partie est consacrée au phénomène des « organisations internationales », sous l angle à la fois de l institutionnalisation progressive des relations internationales et de la difficulté à cerner une catégorie unifiée. La deuxième partie rend compte de la création, de la disparition et des mutations des organisations internationales, ici envisagées comme systèmes institutionnels et ordres juridiques dérivés. La troisième partie analyse l autonomie que l acquisition de la personnalité juridique et de privilèges et immunités, un organe administratif intégré, un personnel ou un budget propres confèrent aux organi...
Chua's Circuit: Control and Synchronization
Irimiciuc, Stefan-Andrei; Vasilovici, Ovidiu; Dimitriu, Dan-Gheorghe
Chaos-based data encryption is one of the most reliable methods used in secure communications. This implies a good control of a chaotic system and a good synchronization between the involved systems. Here, experimental results are shown on the control and synchronization of Chua's circuits. The control of the chaotic circuit was achieved by using the switching method. The influence of the control signal characteristics (amplitude, frequency and shape) on the system's states was also investigated. The synchronization of two similar chaotic circuits was studied, emphasizing the importance of the chaotic state characteristics of the Master system in respect to those of Slave system. It was shown that the synchronization does not depend on the chaotic state type, neither on the dimension (x, y or z) used for synchronization.
Balancing Contention and Synchronization on the Intel Paragon
Bokhari, Shahid H.; Nicol, David M.
1996-01-01
The Intel Paragon is a mesh-connected distributed memory parallel computer. It uses an oblivious and deterministic message routing algorithm: this permits us to develop highly optimized schedules for frequently needed communication patterns. The complete exchange is one such pattern. Several approaches are available for carrying it out on the mesh. We study an algorithm developed by Scott. This algorithm assumes that a communication link can carry one message at a time and that a node can only transmit one message at a time. It requires global synchronization to enforce a schedule of transmissions. Unfortunately global synchronization has substantial overhead on the Paragon. At the same time the powerful interconnection mechanism of this machine permits 2 or 3 messages to share a communication link with minor overhead. It can also overlap multiple message transmission from the same node to some extent. We develop a generalization of Scott's algorithm that executes complete exchange with a prescribed contention. Schedules that incur greater contention require fewer synchronization steps. This permits us to tradeoff contention against synchronization overhead. We describe the performance of this algorithm and compare it with Scott's original algorithm as well as with a naive algorithm that does not take interconnection structure into account. The Bounded contention algorithm is always better than Scott's algorithm and outperforms the naive algorithm for all but the smallest message sizes. The naive algorithm fails to work on meshes larger than 12 x 12. These results show that due consideration of processor interconnect and machine performance parameters is necessary to obtain peak performance from the Paragon and its successor mesh machines.
Synchronous anorectal melanoma
Institute of Scientific and Technical Information of China (English)
Drinko Balicevic; Karla Tomic; Miroslav Bekavac-Beslin; Igor Kovacevic; August Mijic; Mladen Belicza; Bozo Kruslin
2006-01-01
Anorectal melanoma is a very rare tumor with poor prognosis. Rectal bleeding is the most frequent symptom and surgical treatment ranges from local excision to radical abdominoperineal resection. We report a case of a 75-years-old male patient who presented with a history of recurrent rectal bleeding, and whose histopathological diagnosis was melanoma. Macroscopically, we found two distinct tumors in anorectal region, 0.5 cm and 1.5 cm from dentate line. The first one was pedunculated, on a thin stalk, measuring 1 cm in greatest diameter, and the second one was sessile and nodular measuring up to 2.8 cm in largest diameter. Microscopic examination and immunohistochemical analysis of both tumors confirmed the diagnosis of melanoma. This case represents multiple synchronous primary melanoma of the anorectal region, with a possibility that one of the lesions is primary melanoma and the second one is a satellite lesion.
DEFF Research Database (Denmark)
Hansen, Erik W.
, to exist, in order to underline the cognitive basis of man's (comprehension of) existence. A theory of history (existence) is set up on the basis of the traditional dualistic sign function, and the traditional sound-law concept and sound development are reinterpreted in terms of the theory's system...... of definitions. Historical linguistics ('change') is not dependent on an arbitrary synchronic theory. The two language universals polysemy and synonymy are reinterpreted and defined in accordance with the advanced definitions. Louis Hjelmslev's glossematic theory is the general horizon of the argument...... and is criticized for being based on a dated metaphysics. Two epistemological principles are introduced, The Phenomenal Error and The Critico-Philological Method. Conclusion: Historical linguistics is an autonomous scientific discipline. ...
S'appuyer sur l'ergonomie pour concevoir une machine directive "Machines" 2006/42/CE
Bossard, Pascale; Grandjacques, Benoît; Seitier, Sylvie; Thibault, Jean-François
2012-01-01
L'ergonomie est désormais au centre des préoccupations dès lors qu'il s'agit de concevoir des machines. Pour le législateur, très alerte vis-à-vis de cette problématique, l'objectif est avant tout d'aboutir à une meilleure préservation de la santé et de la sécurité des opérateurs. Cet ouvrage, oeuvre commune du Cetim, de la FIM et de l'Anact, a pour objectif de mettre à disposition une méthode commune qui intègre à la fois prévention, notamment des facteurs de pénibilité, réglementation, normalisation et ergonomie. Une publication inédite mêlant deux approches pour une méthodologie commune : celle de l'ingénieur industriel oeuvrant pour l'intégration de la sécurité des machines et la vision d'une agence nationale intervenant dans le domaine de l'amélioration des conditions de travail, en particulier de l'ergonomie.
Condition monitoring of gearboxes using synchronously averaged electric motor signals
Ottewill, J. R.; Orkisz, M.
2013-07-01
Due to their prevalence in rotating machinery, the condition monitoring of gearboxes is extremely important in the minimization of potentially dangerous and expensive failures. Traditionally, gearbox condition monitoring has been conducted using measurements obtained from casing-mounted vibration transducers such as accelerometers. A well-established technique for analyzing such signals is the synchronous signal average, where vibration signals are synchronized to a measured angular position and then averaged from rotation to rotation. Driven, in part, by improvements in control methodologies based upon methods of estimating rotor speed and torque, induction machines are used increasingly in industry to drive rotating machinery. As a result, attempts have been made to diagnose defects using measured terminal currents and voltages. In this paper, the application of the synchronous signal averaging methodology to electric drive signals, by synchronizing stator current signals with a shaft position estimated from current and voltage measurements is proposed. Initially, a test-rig is introduced based on an induction motor driving a two-stage reduction gearbox which is loaded by a DC motor. It is shown that a defect seeded into the gearbox may be located using signals acquired from casing-mounted accelerometers and shaft mounted encoders. Using simple models of an induction motor and a gearbox, it is shown that it should be possible to observe gearbox defects in the measured stator current signal. A robust method of extracting the average speed of a machine from the current frequency spectrum, based on the location of sidebands of the power supply frequency due to rotor eccentricity, is presented. The synchronous signal averaging method is applied to the resulting estimations of rotor position and torsional vibration. Experimental results show that the method is extremely adept at locating gear tooth defects. Further results, considering different loads and different
Analysis of machining and machine tools
Liang, Steven Y
2016-01-01
This book delivers the fundamental science and mechanics of machining and machine tools by presenting systematic and quantitative knowledge in the form of process mechanics and physics. It gives readers a solid command of machining science and engineering, and familiarizes them with the geometry and functionality requirements of creating parts and components in today’s markets. The authors address traditional machining topics, such as: single and multiple point cutting processes grinding components accuracy and metrology shear stress in cutting cutting temperature and analysis chatter They also address non-traditional machining, such as: electrical discharge machining electrochemical machining laser and electron beam machining A chapter on biomedical machining is also included. This book is appropriate for advanced undergraduate and graduate mechani cal engineering students, manufacturing engineers, and researchers. Each chapter contains examples, exercises and their solutions, and homework problems that re...
Dual-scale multimedia dynamic synchronization model
Institute of Scientific and Technical Information of China (English)
李乃祥
2009-01-01
Multimedia synchronization is the key technology in application of distributed multimedia.Solution of synchronization conflicts insides and among streams as well as that of user interaction,synchronization granularity refinement and synchronization precision improvement remain great challenges although great efforts have been invested by the academic circle.The construction method of a dual-scale dynamic synchronous model of multimedia presented in this article realizes multimedia synchronization on two sca...
Photometric Supernova Classification With Machine Learning
Lochner, Michelle; Peiris, Hiranya V; Lahav, Ofer; Winter, Max K
2016-01-01
Automated photometric supernova classification has become an active area of research in recent years in light of current and upcoming imaging surveys such as the Dark Energy Survey (DES) and the Large Synoptic Telescope (LSST), given that spectroscopic confirmation of type for all supernovae discovered with these surveys will be impossible. Here, we develop a multi-faceted classification pipeline, combining existing and new approaches. Our pipeline consists of two stages: extracting descriptive features from the light curves and classification using a machine learning algorithm. Our feature extraction methods vary from model-dependent techniques, namely SALT2 fits, to more independent techniques fitting parametric models to curves, to a completely model-independent wavelet approach. We cover a range of representative machine learning algorithms, including naive Bayes, k-nearest neighbors, support vector machines, artificial neural networks and boosted decision trees. We test the pipeline on simulated multi-ba...
Gestion des communications centrée sur les accès mémoire à distance
Prou, Romain
2015-01-01
National audience; L'émergence des processeurs multi-coeurs a radicalement changé la physionomie des machines courantes et des grappes de calcul. Désormais les noeuds de calcul sont dotés courament de plus de dix coeurs. Cette tendance à l'augmentation du nombre de coeurs par noeud est nette et semble durable, avec l'annonce récente d'Intel de la prochaine génération de Xeon Phi Knights Landing dotée de 72 coeurs et qui sera utilisable en tant que processeur principal. À l'avenir, les machine...
Energy Technology Data Exchange (ETDEWEB)
Pereira, A.; Vega, J.
2005-07-01
The Asynchronous Event Distribution System (AEDS) was built to provides synchronization resources within the TJ-II local area network. It is a software system developed to add soft synchronization capabilities to the TJ-II data acquisition, control and analysis environments Soft synchronization signifies that AEDS is not a realtime system. In fact, AEDS is based on TCP/IP over ETHERNET networks. However, its response time is adequate for practical purposes when synchronization requirements can support some delay between event dispatch and message reception. Event broadcasters (or synchronization servers in AEDS terminology) are Windows computers. Destination computers (or synchronization clients) were also Windows machines in the first version of AEDS. However, this fact imposed a very important limitation on synchronization capabilities. to overcome this situation, synchronization clients for different environments have been added to AEDS: time-sharing operating systems (UNIX and LINUX), real-time operating systems (OS9 and VxWorks) and Java applications. The synchronization primitives that operate in these systems are very different between them and therefore, several approaches were chosen in order to provide the same functionality to the various environments. POSLX thread library with its basic synchronization primitives (mutex and conditions variables) was used to accomplish this task on UNIX/LINUX systems, IPC mechanisms for concurrent processes on OS9 and VxWorks real time operating systems, and synchronized-wait/notify primitives on Java virtual machines. (Author) 11 refs.
Transition to complete synchronization via near-synchronization in two coupled chaotic neurons
Institute of Scientific and Technical Information of China (English)
Wang Qing-Yun; Lu Qi-Shao; Wang Hai-Xia
2005-01-01
The synchronization transition in two coupled chaotic Morris-Lecar (ML) neurons with gap junction is studied with the coupling strength increasing. The conditional Lyapunov exponents, along with the synchronization errors are calculated to diagnose synchronization of two coupled chaotic ML neurons. As a result, it is shown that the increase in the coupling strength leads to incoherence, then induces a transition process consisting of three different synchronization states in succession, namely, burst synchronization, near-synchronization and embedded burst synchronization, and achieves complete synchronization of two coupled neurons finally. These sequential transitions to synchronization reveal a new transition route from incoherence to complete synchronization in coupled systems with multi-time scales.
Vector control of three-phase AC machines system development in the practice
Quang, Nguyen Phung
2008-01-01
Covers the area of vector control of 3-phase AC machines, in particular induction motors with squirrel-cage rotor, permanent excited synchronous motors and doubly-fed induction machines. This title summarizes the basic structure of a field-oriented controlled 3-phase AC drive and grid voltage orientated controlled wind power plant.
Department of Veterans Affairs — Dental Encounter System (DES) is an automated health care application designed to capture critical data about the operations of VA Dental Services. Information on...
2016-01-01
Tableaux Dates d’inauguration des grands hôtels japonais entre 1860 et 1945… 19 Histoire, tourisme et hôtellerie en Corée depuis les années 1870… 59-60 Dates d’inauguration des grands hôtels chinois depuis 1863… 84 Les hôtels de luxe et leurs capacités d’hébergement en Corée en 2000… 103 Les flux de personnes suscités par les hôtels « super luxe » de Séoul en 2000… 105 L’activité des grands hôtels à Séoul en 1999 (en wons)… 106 Propriété et gestion des grands hôtels à Séoul en 1999…. 110 La c...
Chimie des processus biologiques
Fontecave, Marc
2010-01-01
La chimie du vivant : enzymes et métalloenzymes, des biocatalyseurs fascinants La catalyse enzymatique, ce pouvoir que possèdent certaines protéines d’accélérer de façon extraordinaire et d’orienter avec une précision fascinante les réactions chimiques de la cellule, reste, encore aujourd’hui, l’un des grands mystères des systèmes vivants. Les réactions dont il est question vont de la simple hydrolyse de liaisons peptidiques à des processus poly-électroniques d’une très grande complexité, com...
Nutritional recommendations for synchronized swimming.
Robertson, Sherry; Benardot, Dan; Mountjoy, Margo
2014-08-01
The sport of synchronized swimming is unique, because it combines speed, power, and endurance with precise synchronized movements and high-risk acrobatic maneuvers. Athletes must train and compete while spending a great amount of time underwater, upside down, and without the luxury of easily available oxygen. This review assesses the scientific evidence with respect to the physiological demands, energy expenditure, and body composition in these athletes. The role of appropriate energy requirements and guidelines for carbohydrate, protein, fat, and micronutrients for elite synchronized swimmers are reviewed. Because of the aesthetic nature of the sport, which prioritizes leanness, the risks of energy and macronutrient deficiencies are of significant concern. Relative Energy Deficiency in Sport and disordered eating/eating disorders are also of concern for these female athletes. An approach to the healthy management of body composition in synchronized swimming is outlined. Synchronized swimmers should be encouraged to consume a well-balanced diet with sufficient energy to meet demands and to time the intake of carbohydrate, protein, and fat to optimize performance and body composition. Micronutrients of concern for this female athlete population include iron, calcium, and vitamin D. This article reviews the physiological demands of synchronized swimming and makes nutritional recommendations for recovery, training, and competition to help optimize athletic performance and to reduce risks for weight-related medical issues that are of particular concern for elite synchronized swimmers.
Damir Barbaric
2002-01-01
Im Aufsatz wird versucht, den ursprünglichen Sinn der Platonischen Bestimmung vom Staunen als Anfang der Philosophie zu ermitteln, und zwar durch eine kritischen Abhebung von ihrer Umdeutung bei Aristoteles, und dann insbesondere in der Stoa wie auch bei Spinoza und Hegel. Dabei wird auf die frühgriechische Erfahrung vom Staunen als _______ aufmerksam gemacht, wo es vor allem die Grundstimmung des Dabeiseins des Göttlichen und der menschlichen Teilnahme am Göttlichen bedeutet. Dem entspricht ...
2015-01-01
Fariba Adelkhah est chargée de recherche à la Fondation nationale des sciences politiques, Centre d’études et de recherches internationales (CERI) [] Jean-Marie Bouissou est chargé de recherche à la Fondation nationale des sciences politiques, Centre d’études et de recherches internationales (CERI) [] Jean-Louis Briquet est chargé de recherche au CNRS, Centre d’études et de recherches internationales (CERI) [...
Permanent Magnet Synchronous Condenser with Solid State Excitation: Preprint
Energy Technology Data Exchange (ETDEWEB)
Hsu, P.; Muljadi, E.; Wu, Z.; Gao, W.
2015-04-07
A typical synchronous condenser (SC) consists of a free-spinning, wound-field synchronous generator and a field excitation controller. In this paper, we propose an SC that employs a permanent magnet synchronous generator (PMSG) instead of a wound-field machine. PMSGs have the advantages of higher efficiency and reliability. In the proposed configuration, the reactive power control is achieved by a voltage converter controller connected in series to the PMSG. The controller varies the phase voltage of the PMSG and creates the same effect on the reactive power flow as that of an over- or underexcited wound-field machine. The controller’s output voltage magnitude controls the amount of the reactive power produced by the SC. The phase of the controller’s output is kept within a small variation from the grid voltage phase. This small phase variation is introduced so that a small amount of power can be drawn from the grid into the controller to maintain its DC bus voltage. Because the output voltage of the controller is only a fraction of the line voltage, its VA rating is only a fraction of the rating of the PMSG. The proposed scheme is shown to be effective by computer simulations.
Synchronization in an evolving network
Singh, R K
2015-01-01
In this work we study the dynamics of Kuramoto oscillators on a stochastically evolving network whose evolution is governed by the phases of the individual oscillators and degree distribution. Synchronization is achieved after a threshold connection density is reached. This cumulative effect of topology and dynamics has many real-world implications, where synchronization in a system emerges as a collective property of its components in a self-organizing manner. The synchronous state remains stable as long as the connection density remains above the threshold value, with additional links providing resilience against network fluctuations.
Chavanne, A
1989-01-01
Premiere cassette : - 1666 : impact de la creation de l'Academie des Sciences par Colbert, trente ans apres le proces de Galile, et au moment des disparitions de Pascal, Descartes et Fermat. Elle dirigee par le hollandais Huyggens jusqu'a sa fuite de France au moment de la revocation de l'Edit de Nantes. - 1750 : l'Encyclopedie (ou "Dictionnaire raisonne des Sciences, des Arts et des Metiers") de Diderot et d'Alembert, soutenus par Malherbes, Buffon, Condorcet et Rousseau. - 1789 : Revolution francaise. - 8 aout 1793 : l'Assemblee, par une declaration de Marat, dissout l'Academie des Sciences. Celle-ci continue cependant ses travaux pour les poids et mesures jusqu'en 1795. - la Terreur : la condamnation a mort, pas au nom d'une "Revolution qui n'a pas besoin de savants" mais pour d'autres raisons, de trois grands hommes de science : Lavoisier, Bailly et Condorcet. - 1793-1794 : Au printemps 93, le Comite de Salut Publique s'inquiete du demi-million de soldats etrangers de toutes les pays frontaliers qui essai...
Directory of Open Access Journals (Sweden)
Dimitar Spirov
2005-10-01
Full Text Available Two-phase induction machine dynamic model in a coordinate system which rotates at synchronous speed and one-mass dynamic model of mechanism driven in relative units describing transient processes when starting an induction machine in case of constant load conditions are developed.The influence of equivalent circuit parameters of induction machine and mechanism parameters on impact currents and torques and starting time of common used induction machines is studied by means of design of experiment method.
Automation of printing machine
Sušil, David
2016-01-01
Bachelor thesis is focused on the automation of the printing machine and comparing the two types of printing machines. The first chapter deals with the history of printing, typesettings, printing techniques and various kinds of bookbinding. The second chapter describes the difference between sheet-fed printing machines and offset printing machines, the difference between two representatives of rotary machines, technological process of the products on these machines, the description of the mac...
Commande adaptive d'une machine asynchrone
Slama-Belkhodja, I.; de Fornel, B.
1996-06-01
The paper deals with an indirect self-tuning speed control for an induction motor supplied by a chopper-filter-inverter system. Input/Output models are identified with the recursive least squares algorithm and the controller adaptation is based on a pole assignement strategy. Emphasis is put on the evaluation of the parameter identification in order to avoid instabilities because of disturbances or insufficient excitations. This is especially of importance when the adaptive control is carried out in closed loop systems and without additional test signals. Simulation results show the improvement of the dynamic responses and the robustness against load variations or parameters variations (rotor resistance, inertia). Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation et de la nature peu riche en excitations des entrées du processus. Différents régimes transitoires ont été simulés pour apprécier l'apport de cette association (MCR-PP) : démarrages et inversion des sens de rotation, à vide et en charges, applications d'échelons de couple résistant, variations paramétriques. Les résultats permettent d'illustrer, tant au niveau des performances que de la robustesse, l'apport d'une telle commande adaptive pour des entraînements électriques avec une machine asynchrone.
Power balance considerations for brushless doubly-fed machines
Energy Technology Data Exchange (ETDEWEB)
Gorti, B.V.; Alexander, G.C.; Spee, R. [Oregon State Univ., Corvalis, OR (United States). Dept. of Electrical and Computer Engineering
1996-12-01
This paper discusses the power balances in a Brushless Doubly-Fed Machine (BDFM). Equations of power in the two stator windings and the rotor circuit, showing the distribution of electrical and mechanical powers in the air-gap, are obtained in two different speed ranges of BDFM synchronous mode operation. Comparisons vis-a-vis power distribution are made between the Wound-Rotor Induction machine (WRIM) and the BDFM. A brief analysis of the power balances, along with experimental data points obtained using a laboratory prototype machine, are given.
Le dialogisme intertextuel des contes des Grimm
2013-01-01
Loin d'être « purement allemands », nombre de contes des Grimm réécrivent les contes français largement diffusés en Allemagne au XVIIIe siècle en les « reconfigurant » selon leurs propres paradigmes esthétiques et idéologiques. L'étude introductive de la comparatiste Ute Heidmann montre que ce dialogisme européen est resté peu exploré en raison d’une « scénographie en trompe-l’œil » qui les présente comme issus du « terroir » hessois. Toutefois, les notes des Grimm (constituées en volume auto...
Shen, Shixin (Cindy); House, Ronald A.
2017-01-01
Résumé Objectif Permettre aux médecins de famille de comprendre l’épidémiologie, la pathogenèse, les symptômes, le diagnostic et la prise en charge de la maladie des vibrations, une maladie professionnelle importante et courante au Canada. Sources d’information Une recherche a été effectuée sur MEDLINE afin de relever les recherches et comptes rendus portant sur la maladie des vibrations. Une recherche a été effectuée sur Google dans le but d’obtenir la littérature grise qui convient au contexte canadien. D’autres références ont été tirées des articles relevés. Message principal La maladie des vibrations est une maladie professionnelle répandue touchant les travailleurs de diverses industries qui utilisent des outils vibrants. La maladie est cependant sous-diagnostiquée au Canada. Elle compte 3 éléments : vasculaire, sous la forme d’un phénomène de Raynaud secondaire; neurosensoriel; et musculosquelettique. Aux stades les plus avancés, la maladie des vibrations entraîne une invalidité importante et une piètre qualité de vie. Son diagnostic exige une anamnèse minutieuse, en particulier des antécédents professionnels, un examen physique, des analyses de laboratoire afin d’éliminer les autres diagnostics, et la recommandation en médecine du travail aux fins d’investigations plus poussées. La prise en charge consiste à réduire l’exposition aux vibrations, éviter les températures froides, abandonner le tabac et administrer des médicaments. Conclusion Pour assurer un diagnostic rapide de la maladie des vibrations et améliorer le pronostic et la qualité de vie, les médecins de famille devraient connaître cette maladie professionnelle courante, et pouvoir obtenir les détails pertinents durant l’anamnèse, recommander les patients aux cliniques de médecine du travail et débuter les demandes d’indemnisation de manière appropriée. PMID:28292812
Transient-based analysis for the detection of broken damper bars in synchronous motors
Antonino-Daviu, J. A.; Climente-Alarcón, V.; Pons-Llinares, J.; Puche, R.; Pineda-Sánchez, M.
2013-01-01
Synchronous generators and motors constitute critical elements in power generation plants and certain industrial facilities. Damper bars are crucial components of most of these synchronous machines. They enable, among other functions, the direct-on-line starting of these machines, just as if they were asynchronous. Some recent cases, reported by several authors, have demonstrated that eventual failure of damper bars is possible, mainly due to the currents and stresses rising during their operation. In this context, the development of reliable techniques able to diagnose possible damper breakages has attracted significant interest within the fault diagnosis area. The present paper proposes the application of a novel transient-based methodology to diagnose broken damper bars in synchronous motors. This methodology was previously assessed with success in industrial induction motors with diverse sizes. The approach relies on the analysis of the stator startup current demanded by the machine during a direct-on-line starting. To this end, suitable time-frequency decomposition tools are used. In this particular work, the Discrete Wavelet Transform (DWT) is proposed, due to its simplicity, low computational requirements and easy interpretation of its results. Simulation and experimental results obtained with laboratory synchronous machines confirm the validity of the approach for condition monitoring of such windings.
DEFF Research Database (Denmark)
Pitic, Cristian Ilie; Tutelea, Lucian; Boldea, Ion;
2004-01-01
Permanent Magnet-assisted Reluctance Synchronous Machines (PM-RSM) are well known for their lower initial costs and losses in a very wide constant power-speed characteristic. Therefore they are very suitable for hybrid or electrical vehicles. In this application a very good torque control is need...
DEFF Research Database (Denmark)
Pitic, Cristian Ilie; Tutelea, Lucian; Boldea, Ion
2004-01-01
Permanent Magnet-assisted Reluctance Synchronous Machines (PM-RSM) are well known for their lower initial costs and losses in a very wide constant power-speed characteristic. Therefore they are very suitable for hybrid or electrical vehicles. In this application a very good torque control is needed...
Rowe, Robert
2002-05-01
The training of musicians begins by teaching basic musical concepts, a collection of knowledge commonly known as musicianship. Computer programs designed to implement musical skills (e.g., to make sense of what they hear, perform music expressively, or compose convincing pieces) can similarly benefit from access to a fundamental level of musicianship. Recent research in music cognition, artificial intelligence, and music theory has produced a repertoire of techniques that can make the behavior of computer programs more musical. Many of these were presented in a recently published book/CD-ROM entitled Machine Musicianship. For use in interactive music systems, we are interested in those which are fast enough to run in real time and that need only make reference to the material as it appears in sequence. This talk will review several applications that are able to identify the tonal center of musical material during performance. Beyond this specific task, the design of real-time algorithmic listening through the concurrent operation of several connected analyzers is examined. The presentation includes discussion of a library of C++ objects that can be combined to perform interactive listening and a demonstration of their capability.
Incoherence-Mediated Remote Synchronization
Zhang, Liyue; Motter, Adilson E.; Nishikawa, Takashi
2017-04-01
In previously identified forms of remote synchronization between two nodes, the intermediate portion of the network connecting the two nodes is not synchronized with them but generally exhibits some coherent dynamics. Here we report on a network phenomenon we call incoherence-mediated remote synchronization (IMRS), in which two noncontiguous parts of the network are identically synchronized while the dynamics of the intermediate part is statistically and information-theoretically incoherent. We identify mirror symmetry in the network structure as a mechanism allowing for such behavior, and show that IMRS is robust against dynamical noise as well as against parameter changes. IMRS may underlie neuronal information processing and potentially lead to network solutions for encryption key distribution and secure communication.
Synchronous identification of friendly targets
Telle, John M.; Roger, Stutz A.
1998-01-01
A synchronous communication targeting system for use in battle. The present invention includes a transceiver having a stabilizing oscillator, a synchronous amplifier and an omnidirectional receiver, all in electrical communication with each other. A remotely located beacon is attached to a blackbody radiation source and has an amplitude modulator in electrical communication with a optical source. The beacon's amplitude modulator is set so that the optical source transmits radiation frequency at approximately the same or lower amplitude than that of the blackbody radiation source to which the beacon is attached. The receiver from the transceiver is adapted to receive frequencies approximately at or below blackbody radiation signals and sends such signals to the synchronous amplifier. The synchronous amplifier then rectifies and amplifies those signals which correspond to the predetermined frequency to therefore identify whether the blackbody radiation source is friendly or not.
How to suppress undesired synchronization
Louzada, V H P; Andrade, J S; Herrmann, H J
2012-01-01
It is delightful to observe the emergence of synchronization in the blinking of fireflies to attract partners and preys. Other charming examples of synchronization can also be found in a wide range of phenomena such as, e.g., neurons firing, lasers cascades, chemical reactions, and opinion formation. However, in many situations the formation of a coherent state is not pleasant and should be mitigated. For example, the onset of synchronization can be the root of epileptic seizures, traffic congestion in communication networks, and the collapse of constructions. Here we propose the use of contrarians to suppress undesired synchronization. We perform a comparative study of different strategies, either requiring local or total knowledge of the system, and show that the most efficient one solely requires local information. Our results also reveal that, even when the distribution of neighboring interactions is narrow, significant improvement in mitigation is observed when contrarians sit at the highly connected ele...
DEFF Research Database (Denmark)
Valentini, Chiara
2017-01-01
la convergence des rôles respectifs des praticiens des relations publiques et des journalistes a un effet favorable sur la perception qu’ils ont les uns des autres. L’effet est plus marqué chez les praticiens des relations publiques, car leur vision de la profession en journalisme correspond à celle...
Principles of synchronous digital hierarchy
Jain, Rajesh Kumar
2012-01-01
The book presents the current standards of digital multiplexing, called synchronous digital hierarchy, including analog multiplexing technologies. It is aimed at telecommunication professionals who want to develop an understanding of digital multiplexing and synchronous digital hierarchy in particular and the functioning of practical telecommunication systems in general. The text includes all relevant fundamentals and provides a handy reference for problem solving or defining operations and maintenance strategies. The author covers digital conversion and TDM principles, line coding and digital
Chaotic synchronization via linear controller
Institute of Scientific and Technical Information of China (English)
Chen Feng-Xiang; Zhang Wei-Dong
2007-01-01
A technical framework of constructing a linear controller for chaotic synchronization by utilizing the stability theory of cascade-connected system is presented. Based on the method developed in the paper, two simple and linear feedback controllers, as examples, are derived for the synchronization of Liu chaotic system and Duffing oscillator, respectively.This method is quite flexible in constructing a control law. Its effectiveness is also illustrated by the simulation results.
Synchronized Swimming of Two Fish
Koumoutsakos, Petros; Novati, Guido; Abbati, Gabriele; Hejazialhosseini, Babak; van Rees, Wim
2015-11-01
We present simulations of two, self-propelled, fish-like swimmers that perform synchronized moves in a two-dimensional, viscous fluid. The swimmers learn to coordinate by receiving a reward for their synchronized actions. We analyze the swimming patterns emerging for different rewards in terms of their hydrodynamic efficiency and artistic impression. European Research Council (ERC) Advanced Investigator Award (No. 2-73985-14).
Electrical machines and assemblies including a yokeless stator with modular lamination stacks
Energy Technology Data Exchange (ETDEWEB)
Qu, Ronghai; Jansen, Patrick Lee; Bagepalli, Bharat Sampathkumar; Carl, Jr., Ralph James; Gadre, Aniruddha Dattatraya; Lopez, Fulton Jose
2010-04-06
An electrical machine includes a rotor with an inner rotor portion and an outer rotor portion, and a double-sided yokeless stator. The yokeless stator includes modular lamination stacks and is configured for radial magnetic flux flow. The double-sided yokeless stator is concentrically disposed between the inner rotor portion and the outer rotor portion of the electrical machine. Examples of particularly useful embodiments for the electrical machine include wind turbine generators, ship propulsion motors, switch reluctance machines and double-sided synchronous machines.
Photonic Cavity Synchronization of Nanomechanical Oscillators
Bagheri, Mahmood; Poot, Menno; Fan, Linran; Marquardt, Florian; Tang, Hong X.
2013-01-01
Synchronization in oscillatory systems is a frequent natural phenomenon and is becoming an important concept in modern physics. Nanomechanical resonators are ideal systems for studying synchronization due to their controllable oscillation properties and engineerable nonlinearities. Here we demonstrate synchronization of two nanomechanical oscillators via a photonic resonator, enabling optomechanical synchronization between mechanically isolated nanomechanical resonators. Optical backaction gi...
Projet ATI : Halle des matériaux
Babin, Matthieu; Busom Descarrega, Josep; Frisk, Nikolina; Haye, Pierre; Raymond Llorens, Santiago; Thaller, Maxime
2014-01-01
Le Projet halle des matériaux est un projet qui a été créé cette année spécialement pour mettre en place une procédure qualité au sein de celle-ci dans le but in fine de mettre aux normes la machine de Traction MTS 10/M ainsi que la machine de Dureté REICHERTER 250 UV. La mise aux normes attendue par les encadrants est, en fait, la création d'un dossier qualité regroupement les documents nécessaires à l'obtention de l'accréditation. Dans le cas de la Halle des Matériaux, nous pouvions vise...
Directory of Open Access Journals (Sweden)
Dal Georgette
2016-01-01
Full Text Available Les occasionnalismes (nonce formations ou contextual formations dans la terminologie anglo-saxonne, qu’on définira provisoirement comme de “new complex word[s] created by a speaker/writer on the spur of the moment to cover some immediate need” (Bauer, 1983 : 45 ont, à notre connaissance, peu retenu l’attention des morphologues du domaine francophone. Pourtant, toutes les conditions sont désormais réunies pour que cet objet, invisible lorsqu’il s’agissait de décrire le système morphologique du français (ou d’autres langues à partir de ressources dictionnairiques, émerge en tant qu’observable dans une morphologie puisant ses données dans le réel langagier des locuteurs. Par définition en effet, on s’attend à ce qu’un occasionalisme soit absent des dictionnaires (nous verrons que, dans les faits, la situation est plus complexe que cela, et que ces contextual formations ne puissent pas être étudiées en dehors du contexte dans lequel elles ont été produites. À cet égard, la Toile et les produits qui en dérivent constituent des ressources de choix. C’est particulièrement vrai des forums, dans lesquels les internautes s’expriment librement, laissant libre cours à leur potentiel créatif (ou ce qu’ils pensent tel. Dans la présente communication, après avoir défini la notion d’occasionalisme, nous utiliserons un corpus constitué au fil d’autres recherches pour dégager des motifs récurrents propices à leur apparition, autrement dit pour établir une grammaire des occasionnalismes.
VOLTAGE REGULATORS OF SYNCHRONOUS GENERATORS
Directory of Open Access Journals (Sweden)
Grigorash O. V.
2015-06-01
Full Text Available Synchronous generators are the primary source of electrical power autonomous electrosupply systems, including backup systems. They are also used in a structure of rotating electricity converters and are widely used in renewable energy as part of wind power plants of small, mini and micro hydroelectric plants. Increasing the speed and the accuracy of the system of the voltage regulation of synchronous generators is possible due to the development of combined systems containing more stabilizers. The article illustrates the functional schemes of circuit voltage stabilizers and frequency synchronous generators (with electromagnetic excitation and permanent magnet excitation and describes the features of their work, including two and three-aggregate rotating converters of electricity used in uninterruptible power supply systems. To improve the technical characteristics of the system of stabilization we have proposed functional solutions for stabilizers of synchronous generators made on the base of direct frequency converters and using a transformer with a rotating magnetic field. To improve the reliability of and to improve the operational characteristics of the autonomous independent sources of electricity we suggest creating the main functional blocks and the elements of the stabilization system in a modular way. The functional circuit solutions of voltage regulators of synchronous generators and the characteristics of their work considered in the article, are able to improve the efficiency of pre-design work in the development of new technical solutions for stabilizing the voltage and the frequency in synchronous generators of electrosupply autonomous systems
Computer-aided design studies of the homopolar linear synchronous motor
Dawson, G. E.; Eastham, A. R.; Ong, R.
1984-09-01
The linear induction motor (LIM), as an urban transit drive, can provide good grade-climbing capabilities and propulsion/braking performance that is independent of steel wheel-rail adhesion. In view of its 10-12 mm airgap, the LIM is characterized by a low power factor-efficiency product of order 0.4. A synchronous machine offers high efficiency and controllable power factor. An assessment of the linear homopolar configuration of this machine is presented as an alternative to the LIM. Computer-aided design studies using the finite element technique have been conducted to identify a suitable machine design for urban transit propulsion.
Des Vents et des Jets Astrophysiques
Sauty, C.
well expected result from the theory. Although, collimation may be conical, paraboloidal or cylindrical (Part 4), cylindrical collimation is the more likely to occur. The shape of outflows may then be used as a tool to predict physical conditions on the flows or on their source. L'éjection continue de plasma autour d'objets massifs est un phénomène largement répandu en astrophysique, que ce soit sous la forme du vent solaire, de vents stellaires, de jets d'étoiles en formation, de jets stellaires autour d'objets compacts ou de jets extra-galactiques. Cette zoologie diversifiée fait pourtant l'objet d'un commun effort de modélisation. Le but de cette revue est d'abord de présenter qualitativement le développement, depuis leur origine, des diverses théories de vents (Partie 1) et l'inter disciplinarité dans ce domaine. Il s'agit d'une énumération, plus ou moins exhaustive, des idées proposées pour expliquer l'accélération et la morphologie des vents et des jets, accompagnée d'une présentation sommaire des aspects observationnels. Cette partie s'abstient de tout aspect faisant appel au formalisme mathématique. Ces écoulements peuvent être décrits, au moins partiellement, en résolvant les équations magnétohydrodynamiques, axisymétriques et stationnaires. Ce formalisme, à la base de la plupart des théories, est exposé dans la Partie 2. Il permet d'introduire quantitativement les intégrales premières qu'un tel système possède. Ces dernières sont amenées à jouer un rôle important dans la compréhension des phénomènes d'accélération ou de collimation, en particulier le taux de perte de masse, le taux de perte de moment angulaire ou l'énergie du rotateur magnétique. La difficulté de modélisation réside dans l'existence de points critiques, propres aux équations non linéaires, qu'il faut franchir. La nature physique et la localisation de ces points critiques fait l'objet d'un débat important car ils sont la clef de voute de la r
Electrical machines mathematical fundamentals of machine topologies
Gerling, Dieter
2015-01-01
Electrical Machines and Drives play a powerful role in industry with an ever increasing importance. This fact requires the understanding of machine and drive principles by engineers of many different disciplines. Therefore, this book is intended to give a comprehensive deduction of these principles. Special attention is given to the precise mathematical derivation of the necessary formulae to calculate machines and drives and to the discussion of simplifications (if applied) with the associated limits. The book shows how the different machine topologies can be deduced from general fundamentals, and how they are linked together. This book addresses graduate students, researchers, and developers of Electrical Machines and Drives, who are interested in getting knowledge about the principles of machine and drive operation and in detecting the mathematical and engineering specialties of the different machine and drive topologies together with their mutual links. The detailed - but nevertheless compact - mat...
EXPERIENCE WITH SYNCHRONOUS GENERATOR MODEL USING PARTICLE SWARM OPTIMIZATION TECHNIQUE
Directory of Open Access Journals (Sweden)
N.RATHIKA
2014-07-01
Full Text Available This paper intends to the modeling of polyphase synchronous generator and minimization of power losses using Particle swarm optimization (PSO technique with a constriction factor. Usage of Polyphase synchronous generator mainly leads to the total power circulation in the system which can be distributed in all phases. Another advantage of polyphase system is the fault at one winding does not lead to the system shutdown. The Process optimization is the chastisement of adjusting a process so as to optimize some stipulated set of parameters without violating some constraint. Accurate value can be extracted using PSO and it can be reformulated. Modeling and simulation of the machine is executed. MATLAB/Simulink has been cast-off to implement and validate the result.
Multivariable nonlinear control of STATCOM for synchronous generator stabilization
Energy Technology Data Exchange (ETDEWEB)
Sahoo, N.C. [Multimedia Univ., Melaka (Malaysia). Faculty of Engineering and Technology; Panigrahi, B.K.; Panda, G. [Multimedia Univ., Selangor (Malaysia); Dash, P.K. [National Inst. of Technology, Rourkela (India)
2004-01-01
A static synchronous compensator (STATCOM) is a typical flexible ac transmission system device playing a vital role as a stability aid for small and large transient disturbances in an interconnected power system. This article deals with design and evaluation of a feedback linearizing nonlinear controller for STATCOM installed in a single-machine infinite-bus power system. In addition to the coordinated control of ac and dc bus voltages, the proposed controller also provides good damping to the electromechanical oscillation of the synchronous generator under transient disturbances. The efficiency of the control strategy is evaluated by computer simulation studies. The comparative study of these results with the conventional cascade control structure establishes the elegance of the proposed control scheme. (author)
PREDICTION NUMERIQUE DES PERTES SECONDAIRES EN BOUT D'AUBE D'UN COMPRESSEUR AXIAL
Directory of Open Access Journals (Sweden)
A MAOUGAL
1999-12-01
Full Text Available La performance des machines se fait en termes de coefficients de perte de pression et de rendement pour chaque étage. Ce travail rentre dans le cadre du (pre- design des turbomachines. Cette phase préliminaire est devenue indispensable dans le domaine de l’engineering, ce qui permet de donner une approche de la machine avant son dimensionnement, de réaliser un gain économique très important et d’avoir ainsi une idée exacte de ce qu’on veux réaliser.
Intégration des threads temps-réel POSIX sous Java
Le Sommer, Nicolas; Guidec, Frédéric
2001-01-01
National audience; La plupart des machines virtuelles Java actuelles diffèrent dans la manière selon laquelle elles supportent la programmation concurrente. Un même programme concurrent exécuté aujourd'hui sur différentes machines virtuelles se comportera souvent différemment avec chacune d'entre elles. L'environnement Java que nous proposons donne au programmeur un contrôle précis de l'ordonnancement des threads Java s'exécutant sur une plate-forme Linux. Dans cet environnement les threads J...
Laser machining of advanced materials
Dahotre, Narendra B
2011-01-01
Advanced materialsIntroductionApplicationsStructural ceramicsBiomaterials CompositesIntermetallicsMachining of advanced materials IntroductionFabrication techniquesMechanical machiningChemical Machining (CM)Electrical machiningRadiation machining Hybrid machiningLaser machiningIntroductionAbsorption of laser energy and multiple reflectionsThermal effectsLaser machining of structural ceramicsIntrodu
Unidirectional synchronization of Hodgkin-Huxley neurons
Energy Technology Data Exchange (ETDEWEB)
Cornejo-Perez, Octavio [Division de Matematicas Aplicadas y Sistemas, Computacionales, IPICYT, Apdo. Postal 3-74 Tangamanga, 78231 San Luis Potosi (Mexico)]. E-mail: octavio@ipicyt.edu.mx; Femat, Ricardo [Division de Matematicas Aplicadas y Sistemas, Computacionales, IPICYT, Apdo. Postal 3-74 Tangamanga, 78231 San Luis Potosi (Mexico)]. E-mail: rfemat@ipicyt.edu.mx
2005-07-01
Synchronization dynamics of two noiseless Hodgkin-Huxley (HH) neurons under the action of feedback control is studied. The spiking patterns of the action potentials evoked by periodic external modulations attain synchronization states under the feedback action. Numerical simulations for the synchronization dynamics of regular-irregular desynchronized spiking sequences are displayed. The results are discussed in context of generalized synchronization. It is also shown that the HH neurons can be synchronized in face of unmeasured states.
Impulsive Synchronization of Discrete Chaotic Systems
Institute of Scientific and Technical Information of China (English)
郑永爱; 年漪蓓; 刘曾荣
2003-01-01
Impulsive synchronization of two chaotic maps is reformulated as impulsive control of the synchronization error system. We then present a theorem on the asymptotic synchronization of two chaotic maps by using synchronization impulses with varying impulsive intervals. As an example and application of the theorem, we derives some sufficient conditions for the synchronization of two chaotic Lozi maps via impulsive control. The effectiveness of this approach has been demonstrated with chaotic Lozi map.
Impulsive Synchronization of Laser Plasma System
Institute of Scientific and Technical Information of China (English)
LI Yang; LIAO Xiao-Feng; LI Chuan-Dong; CHEN Guo
2007-01-01
The issue of impulsive synchronization of the coupled chaotic laser plasma system is investigated. A new framework for impulsive synchronization of such chaotic systems is presented, which makes the synchronization error system a linear impulsive control system. We derive some sufficient conditions for the synchronization of a laser plasma system via impulsive control with the varying impulsive intervals, which allows us to derive the impulsive synchronization law easily. To illustrate the effectiveness of the proposed results, two numerical examples are given.
Outer Synchronization of Complex Networks by Impulse
Institute of Scientific and Technical Information of China (English)
孙文; 燕子宗; 陈士华; 吕金虎
2011-01-01
This paper investigates outer synchronization of complex networks, especially, outer complete synchronization and outer anti-synchronization between the driving network and the response network. Employing the impulsive control method which is uncontinuous, simple, efficient, low-cost and easy to implement in practical applications, we obtain some sufficient conditions of outer complete synchronization and outer anti-synchronization between two complex networks. Numerical simulations demonstrate the effectiveness of the proposed impulsive control scheme.
Hybrid synchronization of hyperchaotic Lu system
Indian Academy of Sciences (India)
K Sebastian Sudheer; M Sabir
2009-10-01
In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid synchronization between drive and response systems using the sum and difference of relevant variables of the chaotic systems. Numerical simulations are presented to evaluate the analysis and effectiveness of the controllers.
The deleuzian abstract machines
DEFF Research Database (Denmark)
Werner Petersen, Erik
2005-01-01
production. In Kafka: Toward a Minor Literature, Deleuze and Guatari gave the most comprehensive explanation to the abstract machine in the work of art. Like the war-machines of Virilio, the Kafka-machine operates in three gears or speeds. Furthermore, the machine is connected to spatial diagrams...
Energy Conversion Loops for Flux-Switching PM Machine Analysis
Directory of Open Access Journals (Sweden)
E. Ilhan
2012-10-01
Full Text Available Induction and synchronous machines have traditionally been the first choice of automotive manufacturers for electric/hybrid vehicles. However, these conventional machines are not able anymore to meet the increasing demands for a higher energy density due to space limitation in cars. Flux-switching PM (FSPM machines with their high energy density are very suitable to answer this demand. In this paper, the energy conversion loop technique is implemented on FSPM for the first time. The energy conversion technique is a powerful tool for the visualization of machine characteristics, both linear and nonlinear. Further, the technique provides insight into the torque production mechanism. A stepwise explanation is given on how to create these loops for FSPM along with the machine operation.
« Visiochat » et blogue : une combinaison efficace pour le suivi à distance des étudiants
Directory of Open Access Journals (Sweden)
Sandrine Charles
2007-01-01
Full Text Available La visioconférence, outil collaboratif synchrone, permet à des personnes géographiquement distantes de se voir et de dialoguer oralement en temps réel. A contrario, le weblog (ou blogue est un outil collaboratif asynchrone apparenté à un site Web alimenté par des textes, des liens hypertextes et/ou des images publiés au fil de l’eau, par un auteur unique, à titre personnel. Dans le contexte universitaire, visioconférence et blogue présentent de nombreux avantages, notamment pour le suivi des étudiants en stage. Nous discuterons de l’intérêt de la visioconférence pour maintenir la cohésion au sein du groupe, et du blogue comme cahier de laboratoire virtuel.
Synchronous Pendulums and Aliasing
Directory of Open Access Journals (Sweden)
Jia-Cherng Chong
2014-12-01
Full Text Available We present the construction, mathematical relation and simulation of a 16-bob pendulum wave machine (PWM. Following small angle approximation, the PWM is a useful teaching aid to demonstrate free oscillations and periodic motion; it can also illustrate effects of aliasing in physics and engineering. The duration of pattern cycle is adjusted with a set of pendulum lengths that are dictated by a non-linear function followed by the outline of the PWM design aspects. Normal 0 false false false EN-GB X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}
2015-01-01
Intégrer les Tsiganes Hongrie, 1970 (photo DR) 34 Discuter entretient la fraternité. (photo M. Stewart) 35 La veille du mariage (photo M. Stewart) 36 Le « salon » (photo M. Stewart) 37 Les activités économiques des Tsiganes sont conçues comme des jeux. (photo M. Stewart) 39 Lev cheval (photo I. Nemeth) 41 Le cortège d’un mariage (photo M. Stewart) 43 Avant le mariage (photo M. Stewart) 43 C’est par le chant (photo M. Stewart) 45 Des « frères » boivent en harmonie (photo M. Stewart) 46 Les che...
Pritzker, Andreas
2013-01-01
Dieses Buch erzählt die Geschichte des Schweizerischen Instituts für Nuklearforschung (SIN). Das Institut wurde 1968 gegründet und ging 1988 ins Paul Scherrer Institut (PSI) über. Die Gründung des SIN erfolgte in einer Zeit, als die Physik weitherum als Schlüsseldisziplin für die technologische und gesellschaftliche Entwicklung galt. Der Schritt war für ein kleines Land wie die Schweiz ungewöhnliche und zeugte von Mut und Weitsicht. Ungewöhnlich waren der Folge die Leistungen des SIN im weltweiten Vergleich sowie sein Einfluss auf die schweizerische, teils auf die internationale Wissenschaftspolitik.
Les lueurs des sables
2013-01-01
Two CERN ladies are getting ready for the “Trophée Roses des Sables” rally adventure: Julie and Laetitia are finalizing the last details before setting off on Monday 7th October 2013. Julie from EN-MEF group and Laetitia from DGS-SEE group, met at the CERN Rugby club. This year, they are participating in the 100 % female rally which will take place in Morocco from 10 to 20 October. They will be carrying along 100 kg of humanitarian donation for children such as some clothes, books and medical material. Do not hesitate to show your support at their farewell party to be held on Monday 7 October, from 4 to 6 pm in front of the St Genis-Pouilly Mairie (city Hall). Follow their exciting adventure on the blog leslueursdessables.trophee-roses-des-sables.org and on their association’s Facebook page Les Lueurs des Sables.
MAUD : Un prototype de machine à dicter vocale
Fohr, Dominique; Haton, Jean-Paul; Mari, Jean-François; Smaïli, Kamel; Zitouni, Imed
2000-01-01
Contribution à un ouvrage.; La saisie vocale de textes et de données est un important champ d'application des systèmes de reconnaissance automatique de la parole, ainsi que l'un des bancs de test favoris de ces systèmes. l'équipe RFIA/Syco du CRIN/CNRS-INRIA Lorraine développe actuellement une nouvelle version de son système de dictée vocale indépendant du locuteur pour grands vocabulaires, MAUD (Machine AUtomatique à Dicter), fondé essentiellement sur une approche stochastique. Le système MA...
Simplified Model of Brushless Synchronous Generator for Real Time Simulation
Lopez, M D; Rebollo, E; Blanquez, F R
2015-01-01
This paper presents a simplified model of brushless synchronous machine for saving hardware resources in a real time simulation system. Firstly, a brushless excitation system model is described. Thereafter, the simplified transfer function of an AC exciter and rotating diodes of the brushless excitation system is estimated. Finally, the complete system is simulated, comparing the main generator's voltage with both detailed and simplified excitation systems in several scenarios. These results show the accuracy of the simplified model against the detailed simulation model, resulting on an important hardware resources savings.
Grojnowski, Daniel
2015-01-01
À la fin du xixe siècle, les groupes de bohèmes se multiplient et se diversifient, des salons privés aux tavernes ou cabarets. Une étude aussi attentive que possible de trois d’entre eux (les Zutiques, les Hydropathes, les Incohérents) montre la diversité de leurs configurations, ainsi que l’importance déterminante que leurs productions revêt au regard de la postérité.
Differentialdiagnose des Ulcus cruris
Directory of Open Access Journals (Sweden)
Binder B
2010-01-01
Full Text Available Das Ulcus cruris ist eine Erkrankung vor allem des höheren Lebensalters. Ungefähr 1 % der Bevölkerung leidet an einer chronischen Wunde. An die 90 % der Ulzera sind vaskulärer Genese, doch gibt es vielfältige weitere Ursachen. Die Kenntnis der relevanten Differentialdiagnosen ist insbesondere bei therapierefraktären Verläufen von Bedeutung. Dazu gehören Neuropathien, myeloproliferative Erkrankungen, Infektionen, Medikamente oder Hauttumore. Für eine erfolgreiche Behandlung des Ulcus cruris ist die Identifikation der Genese von entscheidender Bedeutung, um eine kausale, interdisziplinäre Therapie zu ermöglichen.
2014-01-01
Amor Hakima, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Angeli Aurora, Universita degli studi di Bologna, Dipartimento di scienze statiche “Paolo Fortunati”, Bologne, Italie. Baali Abdellatif, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Bachtarzi T., Hôpital Ibn Sina, CHU Annaba, Algérie. Baudot Patrick, Université de Proven...
2014-01-01
Amor Hakima, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Angeli Aurora, Universita degli studi di Bologna, Dipartimento di scienze statiche “Paolo Fortunati”, Bologne, Italie. Baali Abdellatif, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Bachtarzi T., Hôpital Ibn Sina, CHU Annaba, Algérie. Baudot Patrick, Université de Proven...
Bodily Synchronization Underlying Joke Telling
Directory of Open Access Journals (Sweden)
R. C. Schmidt
2014-08-01
Full Text Available Advances in video and time series analysis have greatly enhanced our ability to study the bodily synchronization that occurs in natural interactions. Past research has demonstrated that the behavioral synchronization involved in social interactions is similar to dynamical synchronization found generically in nature. The present study investigated how the bodily synchronization in a joke telling task is spread across different nested temporal scales. Pairs of participants enacted knock-knock jokes and times series of their bodily activity were recorded. Coherence and relative phase analyses were used to evaluate the synchronization of bodily rhythms for the whole trial as well as at the subsidiary time scales of the whole joke, the setup of the punch line, the two-person exchange and the utterance. The analyses revealed greater than chance entrainment of the joke teller’s and joke responder’s movements at all time scales and that the relative phasing of the teller’s movements led those of the responder at the longer time scales. Moreover, this entrainment was greater when visual information about the partner’s movements was present but was decreased particularly at the shorter time scales when explicit gesturing in telling the joke was performed. In short, the results demonstrate that a complex interpersonal bodily dance occurs during structured conversation interactions and that this dance is constructed from a set of rhythms associated with the nested behavioral structure of the interaction.
A DES ASIC Suitable for Network Encryption at 10 Gbps and Beyond
Energy Technology Data Exchange (ETDEWEB)
Gass, Karl; Pierson, Lyndon G.; Robertson, Perry J.; Wilcox, D. Craig; Witzke, Edward L.
1999-04-30
The Sandia National Laboratories (SNL) Data Encryption Standard (DES) Application Specific Integrated Circuit (ASIC) is the fastest known implementation of the DES algorithm as defined in the Federal Information Processing Standards (FIPS) Publication 46-2. DES is used for protecting data by cryptographic means. The SNL DES ASIC, over 10 times faster than other currently available DES chips, is a high-speed, filly pipelined implementation offering encryption, decryption, unique key input, or algorithm bypassing on each clock cycle. Operating beyond 105 MHz on 64 bit words, this device is capable of data throughputs greater than 6.7 Billion bits per second (tester limited). Simulations predict proper operation up to 9.28 Billion bits per second. In low frequency, low data rate applications, the ASIC consumes less that one milliwatt of power. The device has features for passing control signals synchronized to throughput data. Three SNL DES ASICS may be easily cascaded to provide the much greater security of triple-key, triple-DES.
ENGINEERING CHARACTERISTICS AND ITS MECHANISM EXPLANATION OF VIBRATORY SYNCHRONIZATION TRANSMISSION
Institute of Scientific and Technical Information of China (English)
Xiong Wanli; Wen Bangchun; Duan Zhishan
2004-01-01
Vibratory synchronization transmission (VST) is a kind of special physical phenomenon in inertia vibra-tion mechanical systems.For an inertia vibration mechanical system driven by one pair of motors runs in step,even the power supply of one motor is cut off,the motor can continue to keep rotating state under the vibration exciting of the machine body driven by only one other motor.And its rotating frequency will be the same as that of the other one.The transient process of this wonderful physical phenomenon has not been described quantitatively according to current-existing mechanical models.On the basis of investigation of the engineering characteristics of VST,a mechanical and electrical coupling mathematical model of a two-shaft inertia vibration machine is established.With this model,the transient process of VST is recurred quantitatively and successfully,and a reasonable explana-tion is given.
Huang, Chengdai; Cao, Jinde
2017-05-01
This paper is concerned with the issues of synchronization and anti-synchronization for fractional chaotic financial system with market confidence by taking advantage of active control approach. Some sufficient conditions are derived to guarantee the synchronization and anti-synchronization for the proposed fractional system. Moreover, the relationship between the order and synchronization(anti-synchronization) is demonstrated numerically. It reveals that synchronization(anti-synchronization) is faster as the order increases. Finally, two illustrative examples are exploited to verify the efficiency of the obtained theoretical results.
Simultaneous Synchronization and Anti-Synchronization of Two Identical New 4D Chaotic Systems
Institute of Scientific and Technical Information of China (English)
GUO Rong-Wei
2011-01-01
We investigate the synchronization and anti-synchronization of the new 4D chaotic system and propose a same adaptive controller in the form which not only synchronizes, but also anti-synchronizes two identical new 4D chaotic systems. Numerical simulations verify the correctness and the effectiveness of the proposed theoretical results.%@@ We investigate the synchronization and anti-synchronization of the new 4D chaotic system and propose a same adaptive controller in the form which not only synchronizes, but also anti-synchronizes two identical new 4D chaotic systems.Numerical simulations verify the correctness and the effectiveness of the proposed theoretical results.
DEFF Research Database (Denmark)
Zhou, Dao; Blaabjerg, Frede; Franke, Toke
2015-01-01
of the low-speed (direct-drive) and medium-speed (one-stage) permanent-magnet synchronous generators are both promising solutions. This paper will assess and compare the reliability metrics for the machine-side converter for those two configurations. First, a translation from the mission profile......, according to the lifetime power cycles, the lifespan can be calculated when operating in various wind classes. It is concluded that, although the low-speed permanent-magnet synchronous generator is able to eliminate the gearbox, the lifespan of its machine-side converter is lower than the one-stage medium...
Ottaviani, J
2005-01-01
Les PFW sont des nappes polaires installées sur les pôles des aimants du PS. Elles sont au nombre de 4 par unité d’aimant et constituées d’un circuit principal (dans lequel circule le courant désiré selon le cycle magnétique utilisé) et de circuits auxiliaires. Les circuits auxiliaires sont des enroulements de correction (“pick-ups” brasés sur les enroulements principaux et boucles de tours). Pendant la variation du champ magnétique de l’aimant PS, on utilise des tensions induites dans ces circuits auxiliaires pour corriger les erreurs de champ dues aux pertes par courants de Foucault dans la chambre à vide. Les corrections à amener pour uniformiser le champ magnétique tout au long de la machine PS sont fonction des différents types de chambres à vide. A ce jour, nous utilisons 18 types de correction différents.
Kang, Dongwoo; Lee, Eonseok; Kim, Hyunchang; Choi, Young-Man; Lee, Seunghyun; Kim, Inyoung; Yoon, Dukkyun; Jo, Jeongdai; Kim, Bongmin; Lee, Taik-Min
2014-06-01
Offset printing processes are promising candidates for producing printed electronics due to their capacity for fine patterning and suitability for mass production. To print high-resolution patterns with good overlay using offset printing, the velocities of two contact surfaces, which ink is transferred between, should be synchronized perfectly. However, an exact velocity of the contact surfaces is unknown due to several imperfections, including tolerances, blanket swelling, and velocity ripple, which prevents the system from being operated in the synchronized condition. In this paper, a novel method of measurement based on the sticking model of friction force was proposed to determine the best synchronized condition, i.e., the condition in which the rate of synchronization error is minimized. It was verified by experiment that the friction force can accurately represent the rate of synchronization error. Based on the measurement results of the synchronization error, the allowable margin of synchronization error when printing high-resolution patterns was investigated experimentally using reverse offset printing. There is a region where the patterning performance is unchanged even though the synchronization error is varied, and this may be viewed as indirect evidence that printability performance is secured when there is no slip at the contact interface. To understand what happens at the contact surfaces during ink transfer, the deformation model of the blanket's surface was developed. The model estimates how much deformation on the blanket's surface can be borne by the synchronization error when there is no slip at the contact interface. In addition, the model shows that the synchronization error results in scale variation in the machine direction (MD), which means that the printing registration in the MD can be adjusted actively by controlling the synchronization if there is a sufficient margin of synchronization error to guarantee printability. The effect of
Synchronization in uncertain complex networks
Chen, Maoyin; Zhou, Donghua
2006-03-01
We consider the problem of synchronization in uncertain generic complex networks. For generic complex networks with unknown dynamics of nodes and unknown coupling functions including uniform and nonuniform inner couplings, some simple linear feedback controllers with updated strengths are designed using the well-known LaSalle invariance principle. The state of an uncertain generic complex network can synchronize an arbitrary assigned state of an isolated node of the network. The famous Lorenz system is stimulated as the nodes of the complex networks with different topologies. We found that the star coupled and scale-free networks with nonuniform inner couplings can be in the state of synchronization if only a fraction of nodes are controlled.
How to suppress undesired synchronization.
Louzada, V H P; Araújo, N A M; Andrade, J S; Herrmann, H J
2012-01-01
Examples of synchronization can be found in a wide range of phenomena such as neurons firing, lasers cascades, chemical reactions, and opinion formation. However, in many situations the formation of a coherent state is not pleasant and should be mitigated. For example, the onset of synchronization can be the root of epileptic seizures, traffic congestion in networks, and the collapse of constructions. Here we propose the use of contrarians to suppress undesired synchronization. We perform a comparative study of different strategies, either requiring local or total knowledge, and show that the most efficient one solely requires local information. Our results also reveal that, even when the distribution of neighboring interactions is narrow, significant improvement is observed when contrarians sit at the highly connected elements. The same qualitative results are obtained for artificially generated networks and two real ones, namely, the Routers of the Internet and a neuronal network.
Multicentric synchronous recurrent aggressive fibromatosis
Directory of Open Access Journals (Sweden)
Kavita Kohli
2012-01-01
Full Text Available Extra-abdominal desmoid tumors are known as aggressive fibromatosis (AFM. Synchronous and metachronous multicentric aggressive fibromatosis are rare lesions and pose dilemma in diagnosis and management. A rare and interesting case of recurrent multicentric, synchronous AFM is presented which to the best of our knowledge has not been reported earlier. A young male presented with well defined, hard, fixed swelling on the thigh. Resected tumor mass on histopathology was diagnosed as an extra abdominal fibromatosis. He presented again after two months with swelling at the same site; and two more swellings on the foot. Fine needle aspiration cytology (FNAC from all three sites was performed; and was suggestive of benign spindle cell lesion of fibrogenic origin with the possibility of multicentric synchronous recurrent aggressive fibromatosis.
Cluster synchronization in oscillatory networks
Belykh, Vladimir N.; Osipov, Grigory V.; Petrov, Valentin S.; Suykens, Johan A. K.; Vandewalle, Joos
2008-09-01
Synchronous behavior in networks of coupled oscillators is a commonly observed phenomenon attracting a growing interest in physics, biology, communication, and other fields of science and technology. Besides global synchronization, one can also observe splitting of the full network into several clusters of mutually synchronized oscillators. In this paper, we study the conditions for such cluster partitioning into ensembles for the case of identical chaotic systems. We focus mainly on the existence and the stability of unique unconditional clusters whose rise does not depend on the origin of the other clusters. Also, conditional clusters in arrays of globally nonsymmetrically coupled identical chaotic oscillators are investigated. The design problem of organizing clusters into a given configuration is discussed.
Phase Synchronization in Railway Timetables
Fretter, Christoph; Weihe, Karsten; Müller-Hannemann, Matthias; Hütt, Marc-Thorsten
2010-01-01
Timetable construction belongs to the most important optimization problems in public transport. Finding optimal or near-optimal timetables under the subsidiary conditions of minimizing travel times and other criteria is a targeted contribution to the functioning of public transport. In addition to efficiency (given, e.g., by minimal average travel times), a significant feature of a timetable is its robustness against delay propagation. Here we study the balance of efficiency and robustness in long-distance railway timetables (in particular the current long-distance railway timetable in Germany) from the perspective of synchronization, exploiting the fact that a major part of the trains run nearly periodically. We find that synchronization is highest at intermediate-sized stations. We argue that this synchronization perspective opens a new avenue towards an understanding of railway timetables by representing them as spatio-temporal phase patterns. Robustness and efficiency can then be viewed as properties of t...
Control of non-conventional synchronous motors
Louis, Jean-Paul
2013-01-01
Classical synchronous motors are the most effective device to drive industrial production systems and robots with precision and rapidity. However, numerous applications require efficient controls in non-conventional situations. Firstly, this is the case with synchronous motors supplied by thyristor line-commutated inverters, or with synchronous motors with faults on one or several phases. Secondly, many drive systems use non-conventional motors such as polyphase (more than three phases) synchronous motors, synchronous motors with double excitation, permanent magnet linear synchronous motors,
SENSITIVE ERROR ANALYSIS OF CHAOS SYNCHRONIZATION
Institute of Scientific and Technical Information of China (English)
HUANG XIAN-GAO; XU JIAN-XUE; HUANG WEI; L(U) ZE-JUN
2001-01-01
We study the synchronizing sensitive errors of chaotic systems for adding other signals to the synchronizing signal.Based on the model of the Henon map masking, we examine the cause of the sensitive errors of chaos synchronization.The modulation ratio and the mean square error are defined to measure the synchronizing sensitive errors by quality.Numerical simulation results of the synchronizing sensitive errors are given for masking direct current, sinusoidal and speech signals, separately. Finally, we give the mean square error curves of chaos synchronizing sensitivity and threedimensional phase plots of the drive system and the response system for masking the three kinds of signals.
A Parameter Communication Optimization Strategy for Distributed Machine Learning in Sensors
Directory of Open Access Journals (Sweden)
Jilin Zhang
2017-09-01
Full Text Available In order to utilize the distributed characteristic of sensors, distributed machine learning has become the mainstream approach, but the different computing capability of sensors and network delays greatly influence the accuracy and the convergence rate of the machine learning model. Our paper describes a reasonable parameter communication optimization strategy to balance the training overhead and the communication overhead. We extend the fault tolerance of iterative-convergent machine learning algorithms and propose the Dynamic Finite Fault Tolerance (DFFT. Based on the DFFT, we implement a parameter communication optimization strategy for distributed machine learning, named Dynamic Synchronous Parallel Strategy (DSP, which uses the performance monitoring model to dynamically adjust the parameter synchronization strategy between worker nodes and the Parameter Server (PS. This strategy makes full use of the computing power of each sensor, ensures the accuracy of the machine learning model, and avoids the situation that the model training is disturbed by any tasks unrelated to the sensors.
A Parameter Communication Optimization Strategy for Distributed Machine Learning in Sensors.
Zhang, Jilin; Tu, Hangdi; Ren, Yongjian; Wan, Jian; Zhou, Li; Li, Mingwei; Wang, Jue; Yu, Lifeng; Zhao, Chang; Zhang, Lei
2017-09-21
In order to utilize the distributed characteristic of sensors, distributed machine learning has become the mainstream approach, but the different computing capability of sensors and network delays greatly influence the accuracy and the convergence rate of the machine learning model. Our paper describes a reasonable parameter communication optimization strategy to balance the training overhead and the communication overhead. We extend the fault tolerance of iterative-convergent machine learning algorithms and propose the Dynamic Finite Fault Tolerance (DFFT). Based on the DFFT, we implement a parameter communication optimization strategy for distributed machine learning, named Dynamic Synchronous Parallel Strategy (DSP), which uses the performance monitoring model to dynamically adjust the parameter synchronization strategy between worker nodes and the Parameter Server (PS). This strategy makes full use of the computing power of each sensor, ensures the accuracy of the machine learning model, and avoids the situation that the model training is disturbed by any tasks unrelated to the sensors.
Schnell, J D
2006-01-01
Dans le cadre des acquisitions des transformateurs rapides des deux LINACS, de la ligne d'injection PSB et de la machine LEIR, un nouveau hardware a été mis en opération [1]. Celui-ci assure la digitalisation des signaux analogiques et aussi de certains signaux de timing devant cadrer la mesure. Pour ce faire des ADC SIS3300 (SIS3320) et des DPRAM 80408 sont mis en service. Ces unités nécéssitent pour leur fonctionnement des horloges et des timings qui normalement sont intégralement fournis par l'équipement standard CO, notamment des CTRV et autres TG8. Suite à des problèmes d'approvisionnement, il existe des cas où l'on ne dispose pas (du moins pour le court terme) de suffisemment de ressources standard pour pourvoir au timing mentionné plus haut. Le tiroir qui fait l'objet de la présente description assure, avec certaines limitations, la génération des timings et autres horloges utilisées par les DPRAM 80408 et les ADC SIS3300.
Die lebensvision des semonides
Directory of Open Access Journals (Sweden)
Milivoj Sironić
1980-12-01
Full Text Available Der Autor analysiert die Weibersatire des Semonides und andere seiner kurzen Fragmente. Dabei kommt er zu der Schlussfolgerung, dass sich die Verse der Satire durch eine gute Technik auszeich nen, dass aber auch eine unnötige Weitschweifigkeit nicht zu Ubersehen ist. Trotzdem kann man jedoch dem Dichter nicht die künstlerische Überzeugungskraft absprechen, wie auch die Ten denz nach Detailschilderungen und die Feinheit geistreicher Charakterisierungen. Die Aussage beinhaltet manchmal eine be stimmte innere Ironie in der Einfachheit der Wörter.In kurzen Fragmenten wird die Fähigkeit des Semonides sichtbar, sich sehr präzise auszudrücken. Seine ironisch-epische Sprache ist sehr reich und verdient vom linguistischen Standpunkt aus Auf merksamkeit wegen ihres reichhaltigen lexischen und termino logischen Materials, insbesondere was die Bereiche der Tier welt und des Essens anbelangt.Die Weltanschauung des Dichters ist in dem ersten Fragment recht deutlich erkennbar. Da sieht man, dass er düster und pessimistisch auf das Leben blickt. Das Fehlen jeglicher positiven Einstellung hat dann den Sar kasmus zur Folge, mit dem der Dichter die Darstellung der Weiber einkleidet, ihn aber auch auf die Menschen schlechthin ausweitet.
Bernardeau, Francis; Laplace, Sandrine; Spiro, Michel
2013-01-01
Écrire l'histoire de l'Univers, tel est l'objectif commun des physiciens des particules et des astrophysiciens. Pour y parvenir, deux approches s'épaulent : la voie de l'infiniment petit, que l'on emprunte via de gigantesques accélérateurs de particules, et celle de l'infiniment grand, dont le laboratoire est l'Univers. Un Univers qui est bien loin d'avoir livré tous ses secrets. On connaît à peine 4,8 % de la matière qui le constitue, le reste étant composé de matière noire (25,8 %) et d'énergie noire (69,4 %), toutes deux de nature inconnue. Et si la récente découverte du boson de Higgs valide le Modèle standard de la physique des particules, celui-ci est toujours incomplet et doit être étendu à ou dépassé. Est-on arrivé au bout du jeu de poupées russes de la matière ? Quelles sont les particules manquantes ? Faut-il revoir les lois fondamentales ? Quels instruments faut-il mettre en œuvre pour accéder à cette « nouvelle physique » ? Comment parler de Super Big Science aux citoye...
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
The annual gala dinner of Chaine des Rotisseurs was hosted by Hilton Beijing. The “Ballet Dinner” - a great creation for both art and fine dining lovers was taken place in varies places within the hotel, including hotel lobby, 3rd floor and lobby lounge.
Club de Yoga
2015-01-01
REPRISE DES COURS – Venez nombreux ! Yoga, Sophrologie, Tai Chi La liste des cours pour le semestre allant du 1er septembre 2015 au 31 janvier 2016 est disponible sur notre site web : http://club-yoga.web.cern.ch Lieu Les cours ont lieu dans la salle des clubs, à l’entresol du restaurant No 2, Bât. 504 (dans la salle no 3 pour la Sophrologie). Prix des cours Le prix pour le semestre (environ 18 leçons) est fixé à 220 CHF plus 10 CHF d’adhésion annuelle au Club. Couple : 200 CHF par personne. 2 cours par semaine : 400 CHF. Inscriptions Les inscriptions aux cours seront prises directement auprès du professeur, lors de la 1ère séance. Avant de s’inscrire pour le semestre, il est possible d’essayer une séance gratuitement. Informations : http://club-yoga.web.cern.ch ----------------------------------------- cern.ch/club-yoga/
Potenziale des Mobile Commerce
Turowski, Klaus
2004-01-01
Potenziale des Mobile Commerce / B. Bazijanec, K. Turowski. - In: Mobile economy : 4. Workshop Mobile Commerce, 02.-03. Februar 2004, Univ. Augsburg / Key Pousttchi ... (Hrsg.). - Bonn : Ges. für Informatik, 2004. - S. 7-11. - (GI-Edition : Proceedings ; 42)
Directory of Open Access Journals (Sweden)
Damir Barbaric
2002-12-01
Full Text Available Im Aufsatz wird versucht, den ursprünglichen Sinn der Platonischen Bestimmung vom Staunen als Anfang der Philosophie zu ermitteln, und zwar durch eine kritischen Abhebung von ihrer Umdeutung bei Aristoteles, und dann insbesondere in der Stoa wie auch bei Spinoza und Hegel. Dabei wird auf die frühgriechische Erfahrung vom Staunen als _______ aufmerksam gemacht, wo es vor allem die Grundstimmung des Dabeiseins des Göttlichen und der menschlichen Teilnahme am Göttlichen bedeutet. Dem entspricht die bei Platon stark hervorgehobene Rolle des “Pathetischen” am Staunen, das in der nachkommenden Tradition grundsätzlich verlorengegangen ist. Für Platon entspringt das Staunen einem nie zu überwindenden Zustand der wesentlichen philosophischen “Weglosigkeit” (_____, welche schon bei Aristoteles nur noch im Sinne eines unbedingt zu verlassenden Ausgangspunkts der methodisch sicher fortfahrenden philosophischen Wissenschaft verstanden wird. Durch ein Zurückgreifen auf die Diotimas Lehre im Dialog Symposion wird dementgegen die Sokratisch-Platonische “Weglosigkeit” als der einzig angemessene “Ort” des echten Philosophierens bestimmt, welchen es, als das “Zwischen” für das Weltspiel der Unsterblichen und Sterblichen, um jeden Preis zu bewahren und offen zu halten gilt.
Forced synchronization of quasiperiodic oscillations
Stankevich, N. V.; Kurths, J.; Kuznetsov, A. P.
2015-01-01
A model of a generator of quasiperiodic oscillations forced by a periodic pulse sequence is studied. We analyze synchronization when the autonomous generator demonstrates periodic, quasiperiodic, respective weakly chaotic oscillations. For the forced quasiperiodic oscillations a picture of synchronization, consisting of small-scale and large-scale structures was uncovered. It even includes the existence of stable the three-frequency tori. For the regime of weak chaos a partial destruction of this features and of the regime of three-frequency tori are found.
Hydraulic Power Plant Machine Dynamic Diagnosis
Directory of Open Access Journals (Sweden)
Hans Günther Poll
2006-01-01
Full Text Available A method how to perform an entire structural and hydraulic diagnosis of prototype Francis power machines is presented and discussed in this report. Machine diagnosis of Francis units consists on a proper evaluation of acquired mechanical, thermal and hydraulic data obtained in different operating conditions of several rotary and non rotary machine components. Many different physical quantities of a Francis machine such as pressure, strains, vibration related data, water flow, air flow, position of regulating devices and displacements are measured in a synchronized way so that a relation of cause an effect can be developed for each operating condition and help one to understand all phenomena that are involved with such kind of machine. This amount of data needs to be adequately post processed in order to allow correct interpretation of the machine dynamics and finally these data must be compared with the expected calculated data not only to fine tuning the calculation methods but also to accomplish fully understanding of the influence of the water passages on such machines. The way how the power plant owner has to operate its Francis machines, many times also determined by a central dispatcher, has a high influence on the fatigue life time of the machine components. The diagnostic method presented in this report helps one to understand the importance of adequate operation to allow a low maintenance cost for the entire power plant. The method how to acquire these quantities is discussed in details together with the importance of correct sensor balancing, calibration and adequate correlation with the physical quantities. Typical results of the dynamic machine behavior, with adequate interpretation, obtained in recent measurement campaigns of some important hydraulic turbines were presented. The paper highlights the investigation focus of the hydraulic machine behavior and how to tailor the measurement strategy to accomplish all goals. Finally some
Koenigsberger, F
1970-01-01
Machine Tool Structures, Volume 1 deals with fundamental theories and calculation methods for machine tool structures. Experimental investigations into stiffness are discussed, along with the application of the results to the design of machine tool structures. Topics covered range from static and dynamic stiffness to chatter in metal cutting, stability in machine tools, and deformations of machine tool structures. This volume is divided into three sections and opens with a discussion on stiffness specifications and the effect of stiffness on the behavior of the machine under forced vibration c
Smile (System/Machine-Independent Local Environment)
Energy Technology Data Exchange (ETDEWEB)
Fletcher, J.G.
1988-04-01
This document defines the characteristics of Smile, a System/machine-independent local environment. This environment consists primarily of a number of primitives (types, macros, procedure calls, and variables) that a program may use; these primitives provide facilities, such as memory allocation, timing, tasking and synchronization beyond those typically provided by a programming language. The intent is that a program will be portable from system to system and from machine to machine if it relies only on the portable aspects of its programming language and on the Smile primitives. For this to be so, Smile itself must be implemented on each system and machine, most likely using non-portable constructions; that is, while the environment provided by Smile is intended to be portable, the implementation of Smile is not necessarily so. In order to make the implementation of Smile as easy as possible and thereby expedite the porting of programs to a new system or a new machine, Smile has been defined to provide a minimal portable environment; that is, simple primitives are defined, out of which more complex facilities may be constructed using portable procedures. The implementation of Smile can be as any of the following: the underlying software environment for the operating system of an otherwise {open_quotes}bare{close_quotes} machine, a {open_quotes}guest{close_quotes} system environment built upon a preexisting operating system, an environment within a {open_quotes}user{close_quotes} process run by an operating system, or a single environment for an entire machine, encompassing both system and {open_quotes}user{close_quotes} processes. In the first three of these cases the tasks provided by Smile are {open_quotes}lightweight processes{close_quotes} multiplexed within preexisting processes or the system, while in the last case they also include the system processes themselves.
Injectabilite des coulis de ciment dans des milieux fissures
Mnif, Thameur
Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.
Energy Technology Data Exchange (ETDEWEB)
Bernard, N.
2001-12-15
A new axial field machine with armature and field windings fixed in the air-gap is studied. A double face printed winding is presented and a new tool, using a surface permeance model is developed. A simplified current control is proposed. Finally, considering the association synchronous machine-inverter the loss minimization problem is investigated, including both geometry and command parameters. (author)
Memory formation by neuronal synchronization.
Axmacher, N.; Mormann, F.; Fernandez, G.; Elger, C.E.; Fell, J.
2006-01-01
Cognitive functions not only depend on the localization of neural activity, but also on the precise temporal pattern of activity in neural assemblies. Synchronization of action potential discharges provides a link between large-scale EEG recordings and cellular plasticity mechanisms. Here, we focus
Process algebra for synchronous communication
Bergstra, J.A.; Klop, J.W.
1984-01-01
Within the context of an algebraic theory of processes, an equational specification of process cooperation is provided. Four cases are considered: free merge or interleaving, merging with communication, merging with mutual exclusion of tight regions, and synchronous process cooperation. The rewrite
Epidemic Synchronization in Robotic Swarms
DEFF Research Database (Denmark)
Schiøler, Henrik; Nielsen, Jens Frederik Dalsgaard; Ngo, Trung Dung
2009-01-01
Clock synchronization in swarms of networked mobile robots is studied in a probabilistic, epidemic framework. In this setting communication and synchonization is considered to be a randomized process, taking place at unplanned instants of geographical rendezvous between robots. In combination wit...
Learning through synchronous electronic discussion
Kanselaar, G.; Veerman, A.L.; Andriessen, J.E.B.
2000-01-01
This article reports a study examining university student pairs carrying out an electronic discussion task in a synchronous computer mediated communication (CMC) system (NetMeeting). The purpose of the assignment was to raise students' awareness concerning conceptions that characterise effective ped
Synchronizing Web Documents with Style
R.L. Guimarães (Rodrigo); D.C.A. Bulterman (Dick); P.S. Cesar Garcia (Pablo Santiago); A.J. Jansen (Jack)
2014-01-01
htmlabstractIn this paper we report on our efforts to define a set of document extensions to Cascading Style Sheets (CSS) that allow for structured timing and synchronization of elements within a Web page. Our work considers the scenario in which the temporal structure can be decoupled from the
Sports Medicine Meets Synchronized Swimming.
Wenz, Betty J.; And Others
This collection of articles contains information about synchronized swimming. Topics covered include general physiology and cardiovascular conditioning, flexibility exercises, body composition, strength training, nutrition, coach-athlete relationships, coping with competition stress and performance anxiety, and eye care. Chapters are included on…
Fermi Timing and Synchronization System
Energy Technology Data Exchange (ETDEWEB)
Wilcox, R.; Staples, J.; Doolittle, L.; Byrd, J.; Ratti, A.; Kaertner, F.X.; Kim, J.; Chen, J.; Ilday, F.O.; Ludwig, F.; Winter, A.; Ferianis, M.; Danailov, M.; D' Auria, G.
2006-07-19
The Fermi FEL will depend critically on precise timing of its RF, laser and diagnostic subsystems. The timing subsystem to coordinate these functions will need to reliably maintain sub-100fs synchronicity between distant points up to 300m apart in the Fermi facility. The technology to do this is not commercially available, and has not been experimentally demonstrated in a working facility. Therefore, new technology must be developed to meet these needs. Two approaches have been researched by different groups working with the Fermi staff. At MIT, a pulse transmission scheme has been developed for synchronization of RF and laser devices. And at LBL, a CW transmission scheme has been developed for RF and laser synchronization. These respective schemes have advantages and disadvantages that will become better understood in coming years. This document presents the work done by both teams, and suggests a possible system design which integrates them both. The integrated system design provides an example of how choices can be made between the different approaches without significantly changing the basic infrastructure of the system. Overall system issues common to any synchronization scheme are also discussed.
Synchronization in Triangled Complex Networks
Institute of Scientific and Technical Information of China (English)
LU Xin-Biao; LI Xiang; WANG Xiao-Fan
2006-01-01
Using a tunable clustering coefficient model withoutchanging the degree distribution, we investigate the effect of clustering coefficient on synchronization of networks with both unweighted and weighted couplings. For several typical categories of complex networks, the more triangles are in the networks, the worse the synchronizability of the networks is.
Synchronizing Web Documents with Style
Guimarães, R.L.; Bulterman, D.C.A.; Cesar Garcia, P.S.; Jansen, A.J.
2014-01-01
In this paper we report on our efforts to define a set of document extensions to Cascading Style Sheets (CSS) that allow for structured timing and synchronization of elements within a Web page. Our work considers the scenario in which the temporal structure can be decoupled from the content of the W
Neural synchronization via potassium signaling
DEFF Research Database (Denmark)
Postnov, Dmitry E; Ryazanova, Ludmila S; Mosekilde, Erik
2006-01-01
Using a relatively simple model we examine how variations of the extracellular potassium concentration can give rise to synchronization of two nearby pacemaker cells. With the volume of the extracellular space and the rate of potassium diffusion as control parameters, the dual nature of this reso...
Synchronized whistlers recorded at Varanasi
Indian Academy of Sciences (India)
Rajesh Singh; Ashok K Singh; R P Singh
2003-06-01
Some interesting events of synchronized whistlers recorded at low latitude station Varanasi during magnetic storm period of the year 1977 are presented. The dynamic spectrum analysis shows that the component whistlers are Eckersley whistlers having dispersion 10 s1/2 and 30 s1/2. An attempt has been made to explain the dynamic spectra using lightning discharge generated from magnetospheric sources.
Modeling Distributed Multimedia Synchronization with DSPN
Institute of Scientific and Technical Information of China (English)
宋军; 顾冠群
1998-01-01
Multimedia synchronization is the essential technology for the integration of multimedia in distributed multimedia systems.The multimedia synchronization model has been recognized by many researchers as a premise of the implementation of multimedia synchronization.In distributed multimedia systems,the characteristic of multimedia synchronization is dynamic,and the key medium has the priority in multimedia synchronization.The previously proposed multimedia synchronization models cannot meet these requirements.So a new multimedia dynamic synchronization model-DSPN,based on the timed Petri-net has been designed in this paper.This model can not only let the distributed multimedia system keep multimedia synchronization in a more precise and effective manner according to the runtime situation of the system,but also allow the user to interact with the presentation of multimedia.
Pinning Synchronization of Switched Complex Dynamical Networks
Directory of Open Access Journals (Sweden)
Liming Du
2015-01-01
Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.
Mikulic, Dinko
2013-01-01
In constant effort to eliminate mine danger, international mine action community has been developing safety, efficiency and cost-effectiveness of clearance methods. Demining machines have become necessary when conducting humanitarian demining where the mechanization of demining provides greater safety and productivity. Design of Demining Machines describes the development and testing of modern demining machines in humanitarian demining. Relevant data for design of demining machines are included to explain the machinery implemented and some innovative and inspiring development solutions. Development technologies, companies and projects are discussed to provide a comprehensive estimate of the effects of various design factors and to proper selection of optimal parameters for designing the demining machines. Covering the dynamic processes occurring in machine assemblies and their components to a broader understanding of demining machine as a whole, Design of Demining Machines is primarily tailored as a tex...
Tschätsch, Heinz
2010-01-01
Machining and cutting technologies are still crucial for many manufacturing processes. This reference presents all important machining processes in a comprehensive and coherent way. It includes many examples of concrete calculations, problems and solutions.
Jackson, Mark J
2011-01-01
Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.
Form, William; McMillen, David Byron
1983-01-01
Data from the first national study of technological change show that proportionately more women than men operate machines, are more exposed to machines that have alienating effects, and suffer more from the negative effects of technological change. (Author/SSH)
Pontier, Matthijs
2015-01-01
The essays in this book, written by researchers from both humanities and sciences, describe various theoretical and experimental approaches to adding medical ethics to a machine in medical settings. Medical machines are in close proximity with human beings, and getting closer: with patients who are in vulnerable states of health, who have disabilities of various kinds, with the very young or very old, and with medical professionals. In such contexts, machines are undertaking important medical tasks that require emotional sensitivity, knowledge of medical codes, human dignity, and privacy. As machine technology advances, ethical concerns become more urgent: should medical machines be programmed to follow a code of medical ethics? What theory or theories should constrain medical machine conduct? What design features are required? Should machines share responsibility with humans for the ethical consequences of medical actions? How ought clinical relationships involving machines to be modeled? Is a capacity for e...
Directory of Open Access Journals (Sweden)
Jose M Carmena
2004-12-01
Full Text Available Dr. Octopus, the villain of the movie "Spiderman 2", is a fusion of man and machine. Neuroscientist Jose Carmena examines the facts behind this fictional account of a brain- machine interface
Dopage et protection des jeunes sportifs : Loin des affaires
Guy, Daniel
2002-01-01
National audience; Loin des affaires et des révélations polémiques de la presse, les jeunes plébiscitent massivement les activités sportives. Sport compétition, sport participation, sport détente... Pourtant, quand la pratique devient intense, que les entraînements et les compétitions s'enchaînent à un rythme soutenu, l'ombre des conduites dopantes vient déchirer la quiétude des uns et des autres. Or, que savons-nous réellement de la pratique des jeunes sportifs ? Comment préparent-ils les co...
The Semiconductor Self-Excitation System of Synchronous Generator with Fuzzy Voltage Regulator
Directory of Open Access Journals (Sweden)
Kutsyk, А.S.
2014-05-01
Full Text Available The synchronous generator’s voltage control system with the synthesized fuzzy voltage regulator is described. The synthesis of the regulator is carried out with the use of mathematical model taking into account the nonlinearity of synchronous machines and semiconductor converters in the e xcitation system. This distinguishes it from traditional excitation regulators, whose synthesis is based on the use of simplified linearized models. The mathematical modeling results allow to compare the control characteristics in the system with the proposed fuzzy voltage regulator and in the system with a traditional voltage controller.
Design of permanent magnet synchronous motor speed control system based on SVPWM
Wu, Haibo
2017-04-01
The control system is designed to realize TMS320F28335 based on the permanent magnet synchronous motor speed control system, and put it to quoting all electric of injection molding machine. The system of the control method used SVPWM, through the sampling motor current and rotating transformer position information, realize speed, current double closed loop control. Through the TMS320F28335 hardware floating-point processing core, realize the application for permanent magnet synchronous motor in the floating point arithmetic, to replace the past fixed-point algorithm, and improve the efficiency of the code.
ANALYSIS OF PARAMETERS AFFECTING THE QUALITY OF A CUTTING MACHINE
Directory of Open Access Journals (Sweden)
Iveta Onderová
2014-02-01
Full Text Available The quality of cutting machines is affected by several factors that can be directly or indirectly influenced by manufacturers, technicians and users of machine tools. The most critical qualitative evaluation parameters of machine tools include accuracy and stability. Investigations of accuracy and repeatable positioning accuracy were essential for the research presented in this paper. The aim was to develop and experimentally verify the design of a methodology for cutting centers aimed at achieving the desired working precision. Before working on the topic described here, it was necessary to make several scientific analyses, which are summarized in this paper. We can build on the initial working hypothesis that by improving the technological parameters (e.g. by increasing the working speed of the machine, or by improving the precision of the positioning the quality of the cutting machine will also be improved. For the purposes of our study, several investigated parameters were set affecting positioning accuracy, such as rigidity, positioning speed, etc. First, the stiffness of the portal structure of the cutting machine was analyzed. FEM analysis was used to investigate several alternative structures of the cutting machine, and also an innovative solution for beam mounting. The second step was to integrate two types of drives into the design of the cutting machine. The first drive is a classic rack and pinion drive for cutting machines. To increase (improve the working speed of the machine, linear motors were designed as an alternative drive. The portal of the cutting machine was designed for a working speed of 260mmin−1 and acceleration of 25 m. s−2. The third step was based on the results of the analysis. In collaboration with Microstep, an experimental cutting machine in a portal version was produced using linear synchronous motors driving the portal on both sides, and with direct linear metering of its position. In the fourth step, an
Robust synchronization of chaotic systems via feedback
Energy Technology Data Exchange (ETDEWEB)
Femat, Ricardo [IPICYT, San Luis Potosi (Mexico). Dept. de Matematicas Aplicadas; Solis-Perales, Gualberto [Universidad de Guadalajara, Centro Univ. de Ciencias Exactas e Ingenierias (Mexico). Div. de Electronica y Computacion
2008-07-01
This volume includes the results derived during last ten years about both suppression and synchronization of chaotic -continuous time- systems. Along this time, the concept was to study how the intrinsic properties of dynamical systems can be exploited to suppress and to synchronize the chaotic behaviour and what synchronization phenomena can be found under feedback interconnection. A compilation of these findings is described in this book. This book shows a perspective on synchronization of chaotic systems. (orig.)
Synchronization effect for uncertain quantum networks
Li, Wenlin; Gebremariam, Tesfay; Li, Chong; Song, Heshan
2017-01-01
We propose a novel technique for investigating the synchronization effect for uncertain networks with quantum chaotic behaviors in this paper. Through designing a special function to construct Lyapunov function of network and the adaptive laws of uncertain parameters, the synchronization between the uncertain network and the synchronization target can be realized, and the uncertain parameters in state equations of the network nodes are perfectly identified. All the theoretical results are verified by numerical simulations to demonstrate the effectiveness of the proposed synchronization technique.
Synchronization in complex clustered networks
Institute of Scientific and Technical Information of China (English)
HUANG Liang; LAI Ying-Cheng; Kwangho PARK; WANG Xingang; LAI Choy Heng; Robert A. GATENBY
2007-01-01
Synchronization in complex networks has been an active area of research in recent years. While much effort has been devoted to networks with the small-world and scale-free topology, structurally they are often assumed to have a single, densely connected component. Recently it has also become apparent that many networks in social, biological, and tech-nological systems are clustered, as characterized by a number (or a hierarchy) of sparsely linked clusters, each with dense and complex internal connections. Synchronization is funda-mental to the dynamics and functions of complex clustered networks, but this problem has just begun to be addressed. This paper reviews some progress in this direction by focus-ing on the interplay between the clustered topology and net-work synchronizability. In particular, there are two parame-ters characterizing a clustered network: the intra-cluster and the inter-cluster link density. Our goal is to clarify the roles of these parameters in shaping network synchronizability. By using theoretical analysis and direct numerical simulations of oscillator networks, it is demonstrated that clustered net-works with random inter-cluster links are more synchroniz-able, and synchronization can be optimized when inter-cluster and intra-cluster links match. The latter result has one coun-terintuitive implication: more links, if placed improperly, can actually lead to destruction of synchronization, even though such links tend to decrease the average network distance. It is hoped that this review will help attract attention to the fun-damental problem of clustered structures/synchronization in network science.
Comparative Simulation Study on Synchronous Generators Sudden Short Circuits
Directory of Open Access Journals (Sweden)
Lucian Lupşa-Tătaru
2009-01-01
Full Text Available Although of a great extent in time, the research works directed at studying transients in synchronous generators have not yet provided fully sufficient comparative studies in respect to sudden short circuits of the machine. The present paper puts forward novel and comprehensive process models for dynamic simulation of short circuit faults of initially unloaded synchronous generators, using the generalized d-q-0 mathematical model as starting point in derivation. Distinct from the time-domain analysis, the technique proposed here allows an effective comparative overview by employing a specialized procedure to perform repeated time-domain simulations accompanied by peak values recording for the various circumstances. The time consuming matrix numerical inversion at each step of integration, usually performed when selecting currents as state variables, is eliminated by advancing the process models in a convenient split matrix form that allows the symbolic processing. Also, the computational efficiency is being increased by introducing a set of auxiliary variables common to different state equations. The models derivation is carried out without altering the structural equations of the generalized d-q-0 mathematical model of synchronous generators whilst the simulation results are both compared and discussed in detail.
BOUDALIA, NADIA
2016-01-01
La richesse et la beauté de la Casbah d’Alger est le fruit de la superposition de différentes strates d’époques et de mode d’occupation spatiales variées. Conférant à la ville des qualités indéniable d’ordre urbain et architectural. Malheureusement, nous assistons aujourd’hui à une marginalisation et une dévalorisation des villes historiques face au développement des périphéries. La ville moderne devient une machine à produire des vides urbains dans les centres historiques; ...
DEFF Research Database (Denmark)
Andersen, Henrik Reif; Mørk, Simon; Sørensen, Morten U.
1997-01-01
Turing showed the existence of a model universal for the set of Turing machines in the sense that given an encoding of any Turing machine asinput the universal Turing machine simulates it. We introduce the concept of universality for reactive systems and construct a CCS processuniversal...
Delay synchronization of temporal Boolean networks
Wei, Qiang; Xie, Cheng-jun; Liang, Yi; Niu, Yu-jun; Lin, Da
2016-01-01
This paper investigates the delay synchronization between two temporal Boolean networks base on semi-tensor product method, which improve complete synchronization. Necessary and sufficient conditions for delay synchronization are drawn base on algebraic expression of temporal Boolean networks. A example is presented to show the effectiveness of theoretical analysis.
Phase multistability of synchronous chaotic oscillations
Directory of Open Access Journals (Sweden)
T. E. Vadivasova
2000-01-01
Full Text Available The paper describes the sequence of bifurcations leading to multistability of periodic and chaotic synchronous attractors for the coupled Rössler systems which individually demonstrate the Feigenbaum route to chaos. We investigate how a frequency mismatch affects this phenomenon. The role of a set of coexisting synchronous regimes in the transitions to and between different forms of synchronization is studied.
Chaotic coupling synchronization of hyperchaotic oscillators
Institute of Scientific and Technical Information of China (English)
Zou Yan-Li; Zhu Jie; Chen Guan-Rong
2005-01-01
In this paper, two kinds of chaotic coupling synchronization schemes are presented. The synchronizability of the coupled hyperchaotic oscillators is proved mathematically and the numerical simulation is also carried out. The numerical calculation of the largest conditional Lyapunov exponent shows that in a given range of coupling strengths,chaotic-coupling synchronization is quicker than the typical continuous-coupling synchronization.
Studies of Machine Learning Photometric Classification of Supernovae
Macaluso, Joseph Nicholas; Cunningham, John; Kuhlmann, Stephen; Gupta, Ravi; Kovacs, Eve
2017-01-01
We studied the use of machine learning for the photometuric classification of Type Ia (SNIa) and core collapse (SNcc) supernovae. We used a combination of simulated data for the Dark Energy survey (DES) and real data from SDSS and chose our metrics to be the sample purity and the efficiency of identifying SNIa supernovae. Our focus was to quantify the effects of varying the training and parameters for random-forest decision-tree algorithms.
Margel,Serge
2017-01-01
Ce séminaire fait suite à un cycle de conférences données en 2014 sur la notion de corps de chair dans le premier christianisme. Cette année la recherche a porté sur le corps spécifique des anges dans la patristique grecque et latine. Sur la base d’un corpus de textes délimité, j’ai essayé de montrer deux choses principales : d’un côté, on ne peut pas comprendre la spécificité du corps des anges sans l’inscrire dans le champ de l’angélologie chrétienne, qui assimile l’ange et l’âme, et d’un a...
Typologie des Accidents Cyclistes
Amoros, Emmanuelle; BILLOT-GRASSET, Alice; Hours, Martine
2015-01-01
L'usage du vélo est en hausse en ville ; cette pratique est encouragée dans le cadre du développement durable et de la lutte contre la sédentarité. Pour accompagner cela, il faut réduire les risques d'accident, et pour ce faire, mieux les connaître. Nous utilisons le Registre des victimes de la circulation routière du Rhône, basé sur les services hospitaliers (dont les urgences) ; il est quasi-exhaustif : env. 1100 blessés à vélo/an versus 120 dans les données officielles. L'ensemble des cycl...
2014-01-01
Présentation schématique de la production et de la transformation de l’acier 16 Chronologie des nationalisations en France 33 Importations de coke de la France 48 Comparaison entre les prix de l’acier en Allemagne et en France, août 1949 99 Prix du marché intérieur et du marché mondial pour les laminés marchands (qualité Thomas) 101 Évolution de la production allemande et française d’acier brut 119 Comparaison des coûts de l’extraction de charbon en Allemagne et en France, 1949 138 Évolution ...
2017-01-01
Illustration de couverture : Dolmen n° 2 des Géandes avec le Mont Ventoux en arrière-plan, octobre 2006 (cliché Wolfgang Pape). Illustration de la quatrième de couverture : René Gilles sur le dolmen n° 5 des Géandes en mars 1989 (cliché Wolfgang Pape). Fig. 1 - Gorges de l’Ardèche au niveau de la grotte de Saint-Marcel (cliché Bernard Gély) 21 Fig. 2 - Doline de Bidon (cliché Wolfgang Pape) 21 Fig. 3 - Paysage de garrigue (cliché Wolfgang Pape) 22 Fig. 4 - Données radio-chronométriques de l’A...
African Journals Online (AJOL)
Synthese
accroissement des pressions sur les écosystèmes et les espèces qu‟ils renferment. La pollution de ... Exacerbée par le changement climatique, cette anthropisation .... majeure partie de son aire de répartition. .... de cette région. .... savoir les impacts à plus grande échelle et ..... habitats et la totalité de l'aire géographique.
Biamonte, Jacob; Wittek, Peter; Pancotti, Nicola; Rebentrost, Patrick; Wiebe, Nathan; Lloyd, Seth
2017-09-13
Fuelled by increasing computer power and algorithmic advances, machine learning techniques have become powerful tools for finding patterns in data. Quantum systems produce atypical patterns that classical systems are thought not to produce efficiently, so it is reasonable to postulate that quantum computers may outperform classical computers on machine learning tasks. The field of quantum machine learning explores how to devise and implement quantum software that could enable machine learning that is faster than that of classical computers. Recent work has produced quantum algorithms that could act as the building blocks of machine learning programs, but the hardware and software challenges are still considerable.
Slocum, Alexander H
1992-01-01
This book is a comprehensive engineering exploration of all the aspects of precision machine design - both component and system design considerations for precision machines. It addresses both theoretical analysis and practical implementation providing many real-world design case studies as well as numerous examples of existing components and their characteristics. Fast becoming a classic, this book includes examples of analysis techniques, along with the philosophy of the solution method. It explores the physics of errors in machines and how such knowledge can be used to build an error budget for a machine, how error budgets can be used to design more accurate machines.
Directory of Open Access Journals (Sweden)
Grazia Nicosia
2010-04-01
Full Text Available Le but de cet article est de comprendre l’incidence sémiotique du nettoyage d’un tableau ainsi que la résultante cognitive induite sur l’observateur. Cette étude confronte l’analyse des phénomènes visuels engendrés par le jaunissement du vernis et son retrait, à des entretiens réalisés à dessein. Le retrait d’un vernis jauni change considérablement l’image. L’heure, le climat, la saison et l’activité même des personnages s’en trouvent ainsi modifié. La patine peut être perçue, soit comme un obstacle à l’exploration, soit pour ceux qui l’apprécient, comme le medium d’une relation plus intime entre l’œuvre et l’observateur.The purpose of this article is to understand the semiotic impact of the cleaning of a painting and the cognitive effects induced on the observer. This study analyses conjointly the visual phenomenon generated by yellowing varnish and its removal and controlled interviews of observers.The removal of yellowing varnish modifies considerably the perception of the picture. Daytime, climate, season and characters activities are modified. The patina may be perceived either as an obstacle to the painting exploration, or, for those who appreciate it, as a medium for a closer relationship between the painting and the observer.
Dictionnaire des risques psychosociaux
Zawieja, Philippe
2014-01-01
Stress, suicide, harcèlement, épuisement professionnel, workaholism... Au-delà de la souffrance qu'elles désignent, ces notions souvent récentes constituent une approche inédite, et demandent à mieux être comprises, dans leur ensemble et isolément. C'est tout l'enjeu de ce dictionnaire, pionnier en son genre. Le lecteur y trouvera représentés, avec les 314 entrées (rédigées par 251 contributeurs) qui le composent, tous les champs disciplinaires s'intéressant à la souffrance au travail : psychologie du travail et des organisations, psychologie sociale et psychosociologie, psychanalyse, psychopathologie et psychiatrie, ergonomie, sociologie du travail et des organisations, médecine du travail, droit du travail et de la sécurité sociale, sciences de gestion, philosophie... Y sont détaillés les principaux concepts, notions, approches, méthodes, théories, outils, études, etc., ayant cours dans l'étude des risques psychosociaux, mais aussi certaines professions emblématiques (infirmières,...
Grundlagen des Tissue Engineering
Mayer, Jörg; Blum, Janaki; Wintermantel, Erich
Die Organtransplantation stellt eine verbreitete Therapie dar, um bei krankheitsoder unfallbedingter Schädigung eines Organs die Gesamtheit seiner Funktionen wieder herzustellen, indem es durch ein Spenderorgan ersetzt wird. Organtransplantationen werden für die Leber, die Niere, die Lunge, das Herz oder bei schweren grossflächigen Verbrennungen der Haut vorgenommen. Der grosse apparative, personelle und logistische Aufwand und die Risiken der Transplantationschirurgie (Abstossungsreaktionen) sowie die mangelnde Verfügbarkeit von immunologisch kompatiblen Spenderorganen führen jedoch dazu, dass der Bedarf an Organtransplantaten nur zu einem sehr geringen Teil gedeckt werden kann. Sind Spenderorgane nicht verfügbar, können in einzelnen Fällen lebenswichtige Teilfunktionen, wie beispielsweise die Filtrationsfunktion der Niere durch die Blutreinigung mittels Dialyse ersetzt oder, bei mangelnder Funktion der Bauchspeicheldrüse (Diabetes), durch die Verabreichung von Insulin ein normaler Zustand des Gesamtorganismus auch über Jahre hinweg erhalten werden. Bei der notwendigen lebenslangen Anwendung apparativer oder medikamentöser Therapie können für den Patienten jedoch häufig schwerwiegende, möglicherweise lebensverkürzende Nebenwirkungen entstehen. Daher werden in der Forschung Alternativen gesucht, um die Funktionen des ausgefallenen Organs durch die Implantation von Zellen oder in vitro gezüchteten Geweben möglichst umfassend wieder herzustellen. Dies erfordert biologisch aktive Implantate, welche die für den Stoffwechsel des Organs wichtigen Zellen enthalten und einen organtypischen Stoffwechsel entfalten.
Partial Synchronization of Interconnected Boolean Networks.
Chen, Hongwei; Liang, Jinling; Lu, Jianquan
2017-01-01
This paper addresses the partial synchronization problem for the interconnected Boolean networks (BNs) via the semi-tensor product (STP) of matrices. First, based on an algebraic state space representation of BNs, a necessary and sufficient criterion is presented to ensure the partial synchronization of the interconnected BNs. Second, by defining an induced digraph of the partial synchronized states set, an equivalent graphical description for the partial synchronization of the interconnected BNs is established. Consequently, the second partial synchronization criterion is derived in terms of adjacency matrix of the induced digraph. Finally, two examples (including an epigenetic model) are provided to illustrate the efficiency of the obtained results.
Energetics of Synchronization in Coupled Oscillators
Izumida, Yuki; Seifert, Udo
2016-01-01
We formulate the energetics of synchronization in coupled oscillators by unifying the nonequilibrium aspects with the nonlinear dynamics via stochastic thermodynamics. We derive a concise and universal expression of the energy dissipation rate using nonlinear-dynamics quantities characterizing synchronization, and elucidate how synchronization/desynchronization between the oscillators affects it. We apply our theory to hydrodynamically-coupled Stokes spheres rotating on circular trajectories that may be interpreted as the simplest model of synchronization of coupled oscillators in a biological system, revealing that the oscillators gain the ability to do more work on the surrounding fluid as the degree of phase synchronization increases.
Cellular automata models for synchronized traffic flow
Jiang Rui
2003-01-01
This paper presents a new cellular automata model for describing synchronized traffic flow. The fundamental diagrams, the spacetime plots and the 1 min average data have been analysed in detail. It is shown that the model can describe the outflow from the jams, the light synchronized flow as well as heavy synchronized flow with average speed greater than approximately 24 km h sup - sup 1. As for the synchronized flow with speed lower than 24 km h sup - sup 1 , it is unstable and will evolve into the coexistence of jams, free flow and light synchronized flow. This is consistent with the empirical findings (Kerner B S 1998 Phys. Rev. Lett. 81 3797).
Modified function projective synchronization of chaotic system
Energy Technology Data Exchange (ETDEWEB)
Du Hongyue [School of Automation, Harbin University of Science and Technology, Harbin 150080 (China); Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001 (China)], E-mail: du_hong_yue@yahoo.com.cn; Zeng Qingshuang; Wang Changhong [Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001 (China)
2009-11-30
This paper presents a new type synchronization called modified function projective synchronization, where the drive and response systems could be synchronized up to a desired scale function matrix. It is obvious that the unpredictability of the scaling functions can additionally enhance the security of communication. By active control scheme, we take Lorenz system as an example to illustrate above synchronization phenomenon. Furthermore, based on modified function projective synchronization, a scheme for secure communication is investigated in theory. The corresponding numerical simulations are performed to verify and illustrate the analytical results.
Photonic cavity synchronization of nanomechanical oscillators.
Bagheri, Mahmood; Poot, Menno; Fan, Linran; Marquardt, Florian; Tang, Hong X
2013-11-22
Synchronization in oscillatory systems is a frequent natural phenomenon and is becoming an important concept in modern physics. Nanomechanical resonators are ideal systems for studying synchronization due to their controllable oscillation properties and engineerable nonlinearities. Here we demonstrate synchronization of two nanomechanical oscillators via a photonic resonator, enabling optomechanical synchronization between mechanically isolated nanomechanical resonators. Optical backaction gives rise to both reactive and dissipative coupling of the mechanical resonators, leading to coherent oscillation and mutual locking of resonators with dynamics beyond the widely accepted phase oscillator (Kuramoto) model. In addition to the phase difference between the oscillators, also their amplitudes are coupled, resulting in the emergence of sidebands around the synchronized carrier signal.
Investigation of Mechanical Loss Components and Heat Transfer in an Axial-Flux PM Machine
Wrobel, Rafal; Vaniel, Gyula; Copeland, Colin; Duda, Tomasz; Staton, David; Mellor, Phil
2015-01-01
This paper investigates components of mechanical loss together with heat transfer effects in an axial-flux permanent-magnet motor. The mechanical loss components generated within electrical machines are well known; however, their prediction or derivation has not been widely reported in the literature. These, together with the electromagnetic loss sources and heat transfer effects, are crucial and must be accounted for when considering high-power-density, high-speed, and/or compact machine des...
Detecting synchronization in coupled stochastic ecosystem networks
Energy Technology Data Exchange (ETDEWEB)
Kouvaris, N. [Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , 15310 Athens (Greece); Department of Mathematical, Physical and Computational Science, Faculty of Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Provata, A. [Institute of Physical Chemistry, National Center for Scientific Research ' Demokritos' , 15310 Athens (Greece); Kugiumtzis, D., E-mail: dkugiu@gen.auth.g [Department of Mathematical, Physical and Computational Science, Faculty of Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
2010-01-11
Instantaneous phase difference, synchronization index and mutual information are considered in order to detect phase transitions, collective behaviours and synchronization phenomena that emerge for different levels of diffusive and reactive activity in stochastic networks. The network under investigation is a spatial 2D lattice which serves as a substrate for Lotka-Volterra dynamics with 3rd order nonlinearities. Kinetic Monte Carlo simulations demonstrate that the system spontaneously organizes into a number of asynchronous local oscillators, when only nearest neighbour interactions are considered. In contrast, the oscillators can be correlated, phase synchronized and completely synchronized when introducing different interactivity rules (diffusive or reactive) for nearby and distant species. The quantitative measures of synchronization show that long distance diffusion coupling induces phase synchronization after a well defined transition point, while long distance reaction coupling induces smeared phase synchronization.
Evaluating Accessible Synchronous CMC Applications
Lobo, Fernando G; Condado, Paulo A; Romão, Teresa; Godinho, Rui; Moreno, Manuel
2010-01-01
This paper proposes a more general evaluation methodology to measure the usability and user experience qualities of accessible synchronous computer-mediated communication applications. The proposed methodology goes beyond current practices by evaluating how the interaction between a user and a product influences the user experience of those at the other endpoint of the communication. Another contribution of the paper is the proposal of a user test where one of the participants tries to guess whether the other participant has a disability or not. An argument is made suggesting that the ultimate goal when designing real-time communication applications is to design mechanisms that can hide the disabilities of users, so that participants involved in the communication do not perceive the disabilities of each other. The proposed ideas are tested and validated with two examples of synchronous communication applications.
Solidarity, synchronization and collective action
Bruggeman, Jeroen
2013-01-01
For people to act collectively in actual situations -- in contrast to public goods experiments -- goal ambiguity, diversity of interests, and uncertain costs and benefits stand in their way. Under such conditions, people seem to have few reasons to cooperate, yet the Arab revolutions, as conspicuous examples, show that collective action can take place despite the odds. I use the Kuramoto model to show how people in a cohesive network topology can synchronize their salient traits (emotions, interests, or other), and that synchronization happens in a phase transition, when group solidarity passes a critical threshold. This yields more precise predictions of outbursts of collective action under adverse conditions, and casts a new light on different measures of social cohesion.
Synchronization of Interacting Quantum Dipoles
Zhu, Bihui; Xu, Minghui; Urbina, Felipe H; Restrepo, Juan G; Holland, Murray J; Rey, Ana Maria
2015-01-01
Macroscopic ensembles of radiating dipoles are ubiquitous in the physical and natural sciences. In the classical limit the dipoles can be described as damped-driven oscillators, which are able to spontaneously synchronize and collectively lock their phases. Here we investigate the correspond- ing phenomenon in the quantum regime with arrays of quantized two-level systems coupled via long-range and anisotropic dipolar interactions. Our calculations demonstrate that the dipoles may overcome the decoherence induced by quantum fluctuations and inhomogeneous couplings and evolve to a synchronized steady-state. This steady-state bears much similarity to that observed in classical systems, and yet also exhibits genuine quantum properties such as quantum correlations and quan- tum phase diffusion (reminiscent of lasing). Our predictions could be relevant for the development of better atomic clocks and a variety of noise tolerant quantum devices.
Synchronization of interacting quantum dipoles
Zhu, B.; Schachenmayer, J.; Xu, M.; Herrera, F.; Restrepo, J. G.; Holland, M. J.; Rey, A. M.
2015-08-01
Macroscopic ensembles of radiating dipoles are ubiquitous in the physical and natural sciences. In the classical limit the dipoles can be described as damped-driven oscillators, which are able to spontaneously synchronize and collectively lock their phases in the presence of nonlinear coupling. Here we investigate the corresponding phenomenon with arrays of quantized two-level systems coupled via long-range and anisotropic dipolar interactions. Our calculations demonstrate that by incoherently driving dense packed arrays of strongly interacting dipoles, the dipoles can overcome the decoherence induced by quantum fluctuations and inhomogeneous coupling and reach a synchronized steady-state characterized by a macroscopic phase coherence. This steady-state bears much similarity to that observed in classical systems, and yet also exhibits genuine quantum properties such as quantum correlations and quantum phase diffusion (reminiscent of lasing). Our predictions could be relevant for the development of better atomic clocks and a variety of noise tolerant quantum devices.
Synchronous clock stopper for microprocessor
Kitchin, David A. (Inventor)
1985-01-01
A synchronous clock stopper circuit for inhibiting clock pulses to a microprocessor in response to a stop request signal, and for reinstating the clock pulses in response to a start request signal thereby to conserve power consumption of the microprocessor when used in an environment of limited power. The stopping and starting of the microprocessor is synchronized, by a phase tracker, with the occurrences of a predetermined phase in the instruction cycle of the microprocessor in which the I/O data and address lines of the microprocessor are of high impedance so that a shared memory connected to the I/O lines may be accessed by other peripheral devices. The starting and stopping occur when the microprocessor initiates and completes, respectively, an instruction, as well as before and after transferring data with a memory. Also, the phase tracker transmits phase information signals over a bus to other peripheral devices which signals identify the current operational phase of the microprocessor.
Reticulation des fibres lignocellulosiques
Landrevy, Christel
Pour faire face à la crise économique la conception de papier à valeur ajoutée est développée par les industries papetières. Le but de se projet est l'amélioration des techniques actuelles de réticulation des fibres lignocellulosiques de la pâte à papier visant à produire un papier plus résistant. En effet, lors des réactions de réticulation traditionnelles, de nombreuses liaisons intra-fibres se forment ce qui affecte négativement l'amélioration anticipée des propriétés physiques du papier ou du matériau produit. Pour éviter la formation de ces liaisons intra-fibres, un greffage sur les fibres de groupements ne pouvant pas réagir entre eux est nécessaire. La réticulation des fibres par une réaction de « click chemistry » appelée cycloaddition de Huisgen entre un azide et un alcyne vrai, catalysée par du cuivre (CuAAC) a été l'une des solutions trouvée pour remédier à ce problème. De plus, une adaptation de cette réaction en milieux aqueux pourrait favoriser son utilisation en milieu industriel. L'étude que nous désirons entreprendre lors de ce projet vise à optimiser la réaction de CuAAC et les réactions intermédiaires (propargylation, tosylation et azidation) sur la pâte kraft, en milieu aqueux. Pour cela, les réactions ont été adaptées en milieu aqueux sur la cellulose microcristalline afin de vérifier sa faisabilité, puis transférée à la pâte kraft et l'influence de différents paramètres comme le temps de réaction ou la quantité de réactifs utilisée a été étudiée. Dans un second temps, une étude des différentes propriétés conférées au papier par les réactions a été réalisée à partir d'une série de tests papetiers optiques et physiques. Mots Clés Click chemistry, Huisgen, CuAAC, propargylation, tosylation, azidation, cellulose, pâte kraft, milieu aqueux, papier.
Research on synchronous gear pump
Institute of Scientific and Technical Information of China (English)
LUAN Zhen-hui
2010-01-01
Based on a comprehensive analysis of the structure and existing problems of the gear pump, provided a structure principle of a synchronous gear pump. The discussions focused on the working principle, construction features and finite element analysis of the hydraulic gear. The research indicates that the new pump has such advantages as lower noise, better distributed flow and a high work pressure, and it can be widely used in hydraulic systems.
Physical Layer Ethernet Clock Synchronization
2010-11-01
42 nd Annual Precise Time and Time Interval (PTTI) Meeting 77 PHYSICAL LAYER ETHERNET CLOCK SYNCHRONIZATION Reinhard Exel , Georg...5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...Austrian Academy of Sciences Viktor Kaplan StraÃe 2, A-2700 Wiener Neustadt, Austria 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING
New Solutions for Synchronized Domineering
Bahri, Sahil; Kruskal, Clyde P.
Cincotti and Iida invented the game of Synchronized Domineering, and analyzed a few special cases. We develop a more general technique of analysis, and obtain results for many more special cases. We obtain complete results for board sizes 3 ×n, 5 ×n, 7 ×n, and 9 ×n (for n large enough) and partial results for board sizes 2×n, 4 ×n, and 6 ×n.
Synchronization Algorithms on Oriented Chains
Directory of Open Access Journals (Sweden)
D. Bein
2008-01-01
Full Text Available We present a space- and time-optimal self-stabilizing algorithm, SSDS, for a given synchronization problem on asynchronous oriented chains. SSDS is uniform and works under the unfair distributed daemon. From SSDS we derive solutions for the local mutual exclusion and distributed sorting. Algorithm SSDS can also be used to obtain optimal space solutions for other problems such as broadcasting, leader election, and mutual exclusion.
SYNCHRONIZATION IN COMPLEX DYNAMICAL NETWORKS
Institute of Scientific and Technical Information of China (English)
WANG Xiaofan; CHEN Guanrong
2003-01-01
In the past few years, the discovery of small-world and scale-free properties of many natural and artificial complex networks has stimulated increasing interest in further studying the underlying organizing principles of various complex networks. This has led to significant advances in understanding the relationship between the topology and the dynamics of such complex networks. This paper reviews some recent research works on the synchronization phenomenon in various dynamical networks with small-world and scalefree connections.
Etude des cas: Gestion alternatîves des conflits
Lo, H.
2006-01-01
Metadata only record Pour mieux consolider les acquis consensuels pour la gestion alternative des conflits, il nous paraît essentiel de maîtriser un certain nombre de facteurs ayant trait au "partage" des gommeraies entre autres: Available in SANREM office, FS
Perspex machine: VII. The universal perspex machine
Anderson, James A. D. W.
2006-01-01
The perspex machine arose from the unification of projective geometry with the Turing machine. It uses a total arithmetic, called transreal arithmetic, that contains real arithmetic and allows division by zero. Transreal arithmetic is redefined here. The new arithmetic has both a positive and a negative infinity which lie at the extremes of the number line, and a number nullity that lies off the number line. We prove that nullity, 0/0, is a number. Hence a number may have one of four signs: negative, zero, positive, or nullity. It is, therefore, impossible to encode the sign of a number in one bit, as floating-point arithmetic attempts to do, resulting in the difficulty of having both positive and negative zeros and NaNs. Transrational arithmetic is consistent with Cantor arithmetic. In an extension to real arithmetic, the product of zero, an infinity, or nullity with its reciprocal is nullity, not unity. This avoids the usual contradictions that follow from allowing division by zero. Transreal arithmetic has a fixed algebraic structure and does not admit options as IEEE, floating-point arithmetic does. Most significantly, nullity has a simple semantics that is related to zero. Zero means "no value" and nullity means "no information." We argue that nullity is as useful to a manufactured computer as zero is to a human computer. The perspex machine is intended to offer one solution to the mind-body problem by showing how the computable aspects of mind and, perhaps, the whole of mind relates to the geometrical aspects of body and, perhaps, the whole of body. We review some of Turing's writings and show that he held the view that his machine has spatial properties. In particular, that it has the property of being a 7D lattice of compact spaces. Thus, we read Turing as believing that his machine relates computation to geometrical bodies. We simplify the perspex machine by substituting an augmented Euclidean geometry for projective geometry. This leads to a general
Machine-tool control system for turning nonaxisymmetric surfaces
Energy Technology Data Exchange (ETDEWEB)
Douglass, S.S.; Green, W.L.
1979-09-01
A development program has been initiated to allow on-axis turning of nonaxisymmetric surfaces. A short-travel high-speed slide is mounted on a precision, numerically controlled, two-axis turning machine. The motion of the auxiliary slide is synchronized with the spindle and the two remaining slides. The report defines the workpiece geometry and requirements, calculations for the slide motion, techniques for real-time command generation, and planned equipment set.
Photometric Supernova Classification with Machine Learning
Lochner, Michelle; McEwen, Jason D.; Peiris, Hiranya V.; Lahav, Ofer; Winter, Max K.
2016-08-01
Automated photometric supernova classification has become an active area of research in recent years in light of current and upcoming imaging surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope, given that spectroscopic confirmation of type for all supernovae discovered will be impossible. Here, we develop a multi-faceted classification pipeline, combining existing and new approaches. Our pipeline consists of two stages: extracting descriptive features from the light curves and classification using a machine learning algorithm. Our feature extraction methods vary from model-dependent techniques, namely SALT2 fits, to more independent techniques that fit parametric models to curves, to a completely model-independent wavelet approach. We cover a range of representative machine learning algorithms, including naive Bayes, k-nearest neighbors, support vector machines, artificial neural networks, and boosted decision trees (BDTs). We test the pipeline on simulated multi-band DES light curves from the Supernova Photometric Classification Challenge. Using the commonly used area under the curve (AUC) of the Receiver Operating Characteristic as a metric, we find that the SALT2 fits and the wavelet approach, with the BDTs algorithm, each achieve an AUC of 0.98, where 1 represents perfect classification. We find that a representative training set is essential for good classification, whatever the feature set or algorithm, with implications for spectroscopic follow-up. Importantly, we find that by using either the SALT2 or the wavelet feature sets with a BDT algorithm, accurate classification is possible purely from light curve data, without the need for any redshift information.
Sémantique et Internet des objets : d'un état de l'art à une ontologie modulaire
Seydoux, Nicolas; Ben Alaya, Mahdi; Hernandez, Nathalie; Monteil, Thierry; Haemmerlé, Ollivier
2015-01-01
National audience; La notion d'Internet des Objets désigne un réseau d'objets connectés entre eux et communiquant de manière automatique. Les notions de sémantiques y ont une place croissante, car plus que jamais elles ap-paraissent comme une solution aux problèmes d'interopérabilité et d'interprétation des données et des services par des machines. La diversité des applications possibles à l'intersection de l'internet des objets et du web sé-mantique a poussé de nombreuses équipes de recherch...
Development of a Synchronous-Generator Experimental Bench for Standstill Time-Domain Tests
Directory of Open Access Journals (Sweden)
M.A. Arjona
2011-08-01
Full Text Available This paper presents the development of an experimental bench for performing time-domain tests on synchronousmachines at standstill. The test bench allows the collection of experimental data which can then be used in theparameter estimation of mathematical models of synchronous motors and generators. The system development isbased on the LabVIEW programming language. It effortlessly allows the calibration of voltage and current sensors, thed-q magnetic axis positioning of the synchronous generator, and the spectral analysis from the collected data. Inaddition, the testing environment includes non-sophisticated instrumentation elements and a power amplifier. Thisexperimental bench has a friendly user interface which guides the user throughout a defined methodology to allow theachievement of the different time domain tests on synchronous machines. A 7kVA, 220V, 60Hz synchronousgenerator was used to show the functionality and usefulness of the test bench in research and teaching electricalmachine theory.
Missile Aerodynamics (Aerodynamique des Missiles)
1998-11-01
guerre froide la production des missiles a baisse’, avec pour consequence une diminution des budgets de d6veloppement. Les nouveaux types de conflits ...Roma) Directeur - Gestion de l’information LUXEMBOURG (Recherche et developpement) - DRDGI 3 Voir Belgique Ministbre de la Difense nationale NORVEGE
Online synchronous communication in the second-language classroom
Directory of Open Access Journals (Sweden)
Elizabeth Murphy
2010-07-01
Full Text Available Abstract: The study reported on in this paper used a framework of benefits, challenges and solutions to categorize data from a design experiment using synchronous online communication for learning French as a second language (FSL. Participants were 92 Grade 6, FSL students and four teachers from urban and rural areas of Newfoundland, Canada. Data collection relied on online observation, teachers’ use of blogs and an online discussion forum, face-to-face planning and reflection meetings for teachers as well as interviews with all participants. Benefits included independence and peer-learning; authenticity and motivation; anonymity and confidence; enhanced self-esteem. Challenges related to teacher multi-tasking; poor sound quality; technical problems; momentum; grouping; scheduling. Solutions included use of student moderators; audio tutorials and direct messaging; activity tutorials; technical support and capacity building. The categories and their subcategories were grouped into two themes of positive affect and student-centered learning. Résumé : L’étude décrite dans le présent article a utilisé un cadre prenant en considération les bénéfices, les défis et les solutions afin de classer les données d’un dispositif expérimental utilisant la communication synchrone en ligne pour l’apprentissage du français langue seconde (FLS. Les participants étaient 92 élèves en FLS de sixième année et quatre enseignants de milieux urbains et ruraux de Terre-Neuve, Canada. La collecte des données s’est fondée sur l’observation en ligne, l’utilisation de cybercarnets et d’un forum de discussion en ligne par les enseignants, la planification en face-à-face et des réunions de réflexion pour les enseignants, ainsi que des entrevues avec tous les participants. Les bénéfices comprenaient : l’indépendance et l’apprentissage entre pairs; l’authenticité et la motivation; l’anonymat et la confiance; l
Al-Toma, AS; Taylor, GA; Abbod, M
2015-01-01
This paper presents the modelling and simulation of a wind turbine driven Permanent Magnet Synchronous Generator connected to a load. The system has been tested at different wind speeds. The machine side controller has been designed to match Maximum Power Point Tracking (MPPT) to obtain high extraction of wind power when connected to a load, while the load side controller fixes the DC voltage that is converted to the AC load voltage. Detailed plots of voltage and current profiles are also pre...
Institute of Scientific and Technical Information of China (English)
孙艳辉; 吴霖生; 翁长晟; 张汆; 贾小丽
2012-01-01
To identify authenticity of Camellia oleif era seed oil quickly,the model was built up by using synchronous fluorescence spectroscopy with support vector machines（SVM）.The experimental results showed that the best model was established by the standard normal variate（SNV） preprocessing,when 5 principal components were selected and the radial basis function（RBF） was used as the kernel function and the optimal penalty factor C and kernel function γ were 0.5 and 0.0313 respectively obtained by the grid searching and cross validation.The discriminate rate of the model was 100% for both training sets and prediction sets.Thus,it was quick and accurate to apply synchronous fluorescence spectroscopy to discriminate the authenticity of Camellia oleif era seed oil based on SVM.%为快速鉴别油茶籽油真伪,采用同步荧光光谱和支持向量机建立油茶籽油真伪鉴别模型。结果表明,原始同步荧光光谱通过标准归一化（SNV）预处理,经过主成分分析提取5个主成分,选用径向基函数（RBF）作为核函数,采用经网格搜索和交叉验证优化得到的两个建模参数惩罚因子C=0.5和核参数γ=0.0313,建立的模型最佳。该模型对训练集和预测集的判别率均可达到100%。说明采用同步荧光光谱结合支持向量机可以快速、准确地鉴别油茶籽油真伪。
Therapie des Status epilepticus
Directory of Open Access Journals (Sweden)
Trinka E
2009-01-01
Full Text Available Der Status epilepticus (SE ist nach dem Schlaganfall der häufigste neurologische Notfall. Er stellt als generaliserter konvulsiver SE (GKSE die schwerste Ausprägung eines epileptischen Anfalls dar, der mit einer signifikanten Morbidität und einer ca. 20%igen Letalität verbunden ist. Nur bei der Hälfte der Patienten mit SE besteht zuvor eine Epilepsie; die meisten Fälle sind symptomatisch, wobei Schädel- Hirn-Traumata, zerebrovaskuläre Erkrankungen, ZNS-Infektionen und metabolische Ursachen führend sind. Bei Patienten mit vorbestehender Epilepsie lässt sich eine frühe Phase des GKSE erkennen, in der die Anfälle crescendoartig zunehmen, bis sie in kontinuierliche Anfallsaktivität münden (etablierte Phase. Das Management eines GKSE verlangt rasches und beherztes Vorgehen. Neben der sofort einzuleitenden Therapie muss gleichzeitig die artdiagnostische Zuordnung des SE und die Ursache erkannt und behandelt werden. Als Therapie der ersten Wahl sind Benzodiazepine etabliert, wobei intravenösem (i.v. Lorazepam gegenüber Diazepam der Vorzug zu geben ist. Versagt die Therapie mit Benzodiazepinen, muss rasch und konsequent nach einem Stufenschema vorgegangen werden. Phenytoin/Fosphenytoin, Valproinsäure, Levetiracetam und Lacosamid sind als i.v. Formulierung erhältliche Antiepileptika. Obwohl Vergleichsstudien hier fehlen, wird Phenytoin bevorzugt. Valproat und Levetiracetam sind nicht sedierend und kardiovaskulär gut verträglich, sodass hier Alternativen zu Phenytoin vorhanden sind. Lacosamid ist eine neue Therapieoption, deren Stellenwert erst bestimmt werden muss. Versagt auch die zweite Therapiestufe, so muss der Patient intubiert und in Allgemeinanästhesie intensivmedizinisch behandelt werden. Dafür stehen Thiopental, Propofol oder hoch dosiertes Midazolam zu Verfügung. Durch den eklatanten Mangel an randomisierten Studien bleibt die Therapie des GKSE empirisch und durch den Off-label-Einsatz gekennzeichnet.
Cengel, Y A
2017-01-01
La mécanique des fluides est un outil performant qui permet d'expliquer les phénomènes qui nous entourent de l'échelle microscopique à l'échelle macroscopique. Elle est aussi à la base du développement de nombreuses technologies. Cet ouvrage à destination des étudiants donne une vision complète de la mécanique des fluides. Bien que la mécanique des fluides puisse souvent paraître rébarbative aux yeux des étudiants, cet ouvrage valorise ce domaine d'enseignement en l'illustrant de nombreux exemples issus de l'ingénierie navale, l'aéronautique, la météorologie, etc.
Institute of Scientific and Technical Information of China (English)
Feng Xiu-Qin; Shen Ke
2005-01-01
We have investigated chaotic synchronization in the generalized sense for the degenerate optical parametric oscillator (DOPO). The numerical results show that two unidirectional coupling DOPOs in chaos can be completely phase synchronization or anti-phase synchronization with a suitable coupling coefficient under which the maximum condition Lyapunov exponent (MCLE) is negative. Phase synchronization and anti-phase synchronization of chaos can be realized through positive and negative coupling. On the other hand, the different synchronization states depend on the coupling types used in the DOPO systems.
Machinability of advanced materials
Davim, J Paulo
2014-01-01
Machinability of Advanced Materials addresses the level of difficulty involved in machining a material, or multiple materials, with the appropriate tooling and cutting parameters. A variety of factors determine a material's machinability, including tool life rate, cutting forces and power consumption, surface integrity, limiting rate of metal removal, and chip shape. These topics, among others, and multiple examples comprise this research resource for engineering students, academics, and practitioners.
Pattern recognition & machine learning
Anzai, Y
1992-01-01
This is the first text to provide a unified and self-contained introduction to visual pattern recognition and machine learning. It is useful as a general introduction to artifical intelligence and knowledge engineering, and no previous knowledge of pattern recognition or machine learning is necessary. Basic for various pattern recognition and machine learning methods. Translated from Japanese, the book also features chapter exercises, keywords, and summaries.
Support vector machines applications
Guo, Guodong
2014-01-01
Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.
2014-01-01
This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.
Suzuki, Hideyuki; Imura, Jun-ichi; Horio, Yoshihiko; Aihara, Kazuyuki
2013-01-01
The chaotic Boltzmann machine proposed in this paper is a chaotic pseudo-billiard system that works as a Boltzmann machine. Chaotic Boltzmann machines are shown numerically to have computing abilities comparable to conventional (stochastic) Boltzmann machines. Since no randomness is required, efficient hardware implementation is expected. Moreover, the ferromagnetic phase transition of the Ising model is shown to be characterised by the largest Lyapunov exponent of the proposed system. In general, a method to relate probabilistic models to nonlinear dynamics by derandomising Gibbs sampling is presented.
Stolarski, Tadeusz
1999-01-01
""Tribology in Machine Design is strongly recommended for machine designers, and engineers and scientists interested in tribology. It should be in the engineering library of companies producing mechanical equipment.""Applied Mechanics ReviewTribology in Machine Design explains the role of tribology in the design of machine elements. It shows how algorithms developed from the basic principles of tribology can be used in a range of practical applications within mechanical devices and systems.The computer offers today's designer the possibility of greater stringen
Energy Technology Data Exchange (ETDEWEB)
Miller, P.; Pizzi, R.
1994-09-02
A computer program is really nothing more than a virtual machine built to perform a task. The program`s source code expresses abstract constructs using low level language features. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low level machine implementation in formation to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design into the source code. We introduce OODIE, an object-oriented language extension that allows programmers to specify a virtual debugging environment which includes the design and abstract data types of the virtual machine.
Hammond, P
1985-01-01
Containing approximately 200 problems (100 worked), the text covers a wide range of topics concerning electrical machines, placing particular emphasis upon electrical-machine drive applications. The theory is concisely reviewed and focuses on features common to all machine types. The problems are arranged in order of increasing levels of complexity and discussions of the solutions are included where appropriate to illustrate the engineering implications. This second edition includes an important new chapter on mathematical and computer simulation of machine systems and revised discussions o
Lantz, Brett
2013-01-01
Written as a tutorial to explore and understand the power of R for machine learning. This practical guide that covers all of the need to know topics in a very systematic way. For each machine learning approach, each step in the process is detailed, from preparing the data for analysis to evaluating the results. These steps will build the knowledge you need to apply them to your own data science tasks.Intended for those who want to learn how to use R's machine learning capabilities and gain insight from your data. Perhaps you already know a bit about machine learning, but have never used R; or
Boldea, Ion
2002-01-01
Often called the workhorse of industry, the advent of power electronics and advances in digital control are transforming the induction motor into the racehorse of industrial motion control. Now, the classic texts on induction machines are nearly three decades old, while more recent books on electric motors lack the necessary depth and detail on induction machines.The Induction Machine Handbook fills industry's long-standing need for a comprehensive treatise embracing the many intricate facets of induction machine analysis and design. Moving gradually from simple to complex and from standard to
Molekulare Formen des PSA in der Diagnostik des Prostatakarzinoms
Directory of Open Access Journals (Sweden)
Lein M
2003-01-01
Full Text Available Das prostataspezifische Antigen ist die wichtigste Kenngröße in der Diagnostik und Therapieüberwachung des Prostatakarzinoms. Zur besseren Abgrenzung zwischen Männern mit und ohne Prostatakarzinom, aber auch zur Früherkennung, haben sich die molekularen Formen des PSA als wertvolle Entscheidungshilfen erwiesen. Es wird eine Übersicht über bisher vorliegende Informationen zur Aussagekraft des freien PSA, des an alpha 1-Antichymotrypsin gebundenen PSA und des komplexierten PSA (cPSA zusammen mit eigenen Resultaten gegeben. Der Quotient aus freiem und Gesamt-PSA hat sich als eine wichtige Entscheidungsgröße in der urologischen Praxis etabliert, mit der Sensitivität und Spezifität der Prostatakarzinomdiagnostik verbessert werden. Die Zahl von Prostatastanzbiopsien im Gesamt-PSA-Bereich von 4–10 ng/ml kann damit reduziert werden. Ein diagnostischer Vorteil der alleinigen Bestimmung des komplexierten PSA bzw. der entsprechenden Quotienten im Vergleich zum Gesamt-PSA und des Quotienten freies PSA zu Gesamt-PSA konnte bisher nicht sicher nachgewiesen werden.
Mécanique des sols et des roches
Vullier, Laurent; Zhao, Jian
2016-01-01
La mécanique des sols et la mécanique des roches sont des disciplines généralement traitées séparément dans la littérature. Pour la première fois, un traité réunit ces deux spécialités, en intégrant également les connaissances en lien avec les écoulements souterrains et les transferts thermiques. A la fois théorique et pratique, cet ouvrage propose tout d'abord une description détaillée de la nature et de la composition des sols et des roches, puis s'attache à la modélisation de problèmes aux conditions limites et présente les essais permettant de caractériser les sols et les roches, tant d'un point de vue mécanique qu'hydraulique et thermique. La problématique des sols non saturés et des écoulements multiphasiques est également abordée. Une attention particulière est portée aux lois de comportement mécanique et à la détermination de leurs paramètres par des essais in situ et en laboratoire, et l'ouvrage offre également une présentation détaillée des systèmes de classi...
A chimeric path to neuronal synchronization
Essaki Arumugam, Easwara Moorthy; Spano, Mark L.
2015-01-01
Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an "all or none" phenomenon, but can pass through an intermediate stage (chimera).
Synchronizing noisy nonidentical oscillators by transient uncoupling
Energy Technology Data Exchange (ETDEWEB)
Tandon, Aditya, E-mail: adityat@iitk.ac.in; Mannattil, Manu, E-mail: mmanu@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Schröder, Malte, E-mail: malte@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Timme, Marc, E-mail: timme@nld.ds.mpg.de [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Department of Physics, Technical University of Darmstadt, 64289 Darmstadt (Germany); Chakraborty, Sagar, E-mail: sagarc@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India); Mechanics and Applied Mathematics Group, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh 208016 (India)
2016-09-15
Synchronization is the process of achieving identical dynamics among coupled identical units. If the units are different from each other, their dynamics cannot become identical; yet, after transients, there may emerge a functional relationship between them—a phenomenon termed “generalized synchronization.” Here, we show that the concept of transient uncoupling, recently introduced for synchronizing identical units, also supports generalized synchronization among nonidentical chaotic units. Generalized synchronization can be achieved by transient uncoupling even when it is impossible by regular coupling. We furthermore demonstrate that transient uncoupling stabilizes synchronization in the presence of common noise. Transient uncoupling works best if the units stay uncoupled whenever the driven orbit visits regions that are locally diverging in its phase space. Thus, to select a favorable uncoupling region, we propose an intuitive method that measures the local divergence at the phase points of the driven unit's trajectory by linearizing the flow and subsequently suppresses the divergence by uncoupling.
Synchronization of chaotic systems with different order.
Femat, Ricardo; Solís-Perales, Gualberto
2002-03-01
The chaotic synchronization of third-order systems and second-order driven oscillator is studied in this paper. Such a problem is related to synchronization of strictly different chaotic systems. We show that dynamical evolution of second-order driven oscillators can be synchronized with the canonical projection of a third-order chaotic system. In this sense, it is said that synchronization is achieved in reduced order. Duffing equation is chosen as slave system whereas Chua oscillator is defined as master system. The synchronization scheme has nonlinear feedback structure. The reduced-order synchronization is attained in a practical sense, i.e., the difference e=x(3)-x(1)(') is close to zero for all time t> or =t(0)> or =0, where t(0) denotes the time of the control activation.
A chimeric path to neuronal synchronization
Energy Technology Data Exchange (ETDEWEB)
Essaki Arumugam, Easwara Moorthy; Spano, Mark L. [School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709 (United States)
2015-01-15
Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)
Virtual machine vs Real Machine: Security Systems
Directory of Open Access Journals (Sweden)
Dr. C. Suresh Gnana Das
2009-08-01
Full Text Available This paper argues that the operating system and applications currently running on a real machine should relocate into a virtual machine. This structure enables services to be added below the operating system and to do so without trusting or modifying the operating system or applications. To demonstrate the usefulness of this structure, we describe three services that take advantage of it: secure logging, intrusion prevention and detection, and environment migration. In particular, we can provide services below the guest operating system without trusting or modifying it. We believe providing services at this layer are especially useful for enhancing security and mobility. This position paper describes the general benefits and challenges that arise from running most applications in a virtual machine, and then describes some example services and alternative ways to provide those services.
Explosive synchronization coexists with classical synchronization in the Kuramoto model
Danziger, Michael M.; Moskalenko, Olga I.; Kurkin, Semen A.; Zhang, Xiyun; Havlin, Shlomo; Boccaletti, Stefano
2016-06-01
Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ˜ 106) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.
Explosive synchronization coexists with classical synchronization in the Kuramoto model
Energy Technology Data Exchange (ETDEWEB)
Danziger, Michael M., E-mail: michael.danziger@biu.ac.il; Havlin, Shlomo [Department of Physics, Bar-Ilan University, Ramat Gan (Israel); Moskalenko, Olga I.; Kurkin, Semen A. [Faculty of Nonlinear Processes, Saratov State University, Astrakhanskaya, 83, Saratov 410012 (Russian Federation); Saratov State Technical University, Politehnicheskaya, 77, Saratov 410054 (Russian Federation); Zhang, Xiyun [Department of Physics, East China Normal University, Shanghai 200062 (China); Boccaletti, Stefano [CNR-Institute of Complex Systems, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence (Italy); The Italian Embassy in Israel, 25 Hamered Street, 68125 Tel Aviv (Israel)
2016-06-15
Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ∼ 10{sup 6}) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.
L'intégration des accélérateurs du CERN
Chemli, S; CERN. Geneva. TS Department
2008-01-01
L?intégration du LHC a ouvert des perspectives pour une gestion plus complète des accélérateurs du CERN. La base de données LAYOUT a permis d'assurer la continuité des phases de définition optique du projet, d'intégration 3D et de contrôles de conformité des installations. Les scans et modélisations 3D en couches des installations réalisées constituent un outil déterminant pour la préparation des interventions dans le cadre des procédures de sécurité ALARA. Il est proposé de reproduire cette méthodologie pour les nouveaux projets comme pour les accélérateurs existants. La mise à jour de l'anneau SPS dans LAYOUT semble être la priorité. La base de données SURVEY contient déjà une vue d'ensemble des accélérateurs, chaque composant étant référencé dans le Système de Coordonnées du CERN, selon les définitions théoriques "sources" au 1/100 mm. Base pour l'alignement, elle stocke également les positions réelles des machines. Elle complète ainsi l'information linéaire de LAY...
Directory of Open Access Journals (Sweden)
BERNARD ROY
2012-01-01
Full Text Available Ce texte est avant tout une réflexion sur la notion d'obéissance, initiée à partir de deux évènements impliquant étroitement des membres de la profession infirmière. L'auteur se réjouit de la prise de parole et de l'implication directe d'infirmières dans le contexte du printemps érable. Il estime que la posture de ces infirmières s'inscrit dans ce que l'éthicien Guy Durand, appelle une obéissance autonome qui peut, du coup, mener à la désobéissance civile, à l'objection de conscience. En prenant exemple sur le silence des infirmières dans le contexte de la fermeture de postes d'infirmières en Minganie, l'auteur estime que cette posture est marginale chez les infirmières qui, majoritairement, adoptent une position de soumission et d'obéissance hétéronome.
Synchronization in random balanced networks
García del Molino, Luis Carlos; Pakdaman, Khashayar; Touboul, Jonathan; Wainrib, Gilles
2013-10-01
Characterizing the influence of network properties on the global emerging behavior of interacting elements constitutes a central question in many areas, from physical to social sciences. In this article we study a primary model of disordered neuronal networks with excitatory-inhibitory structure and balance constraints. We show how the interplay between structure and disorder in the connectivity leads to a universal transition from trivial to synchronized stationary or periodic states. This transition cannot be explained only through the analysis of the spectral density of the connectivity matrix. We provide a low-dimensional approximation that shows the role of both the structure and disorder in the dynamics.
Noise-Mediated Generalized Synchronization
Institute of Scientific and Technical Information of China (English)
CHEN Yue-Hua; WU Zhi-Yuan; YANG Jun-Zhong
2007-01-01
@@ We investigate a drive-response system by considering the impacts of noise on generalized synchronization (GS).It is found that a small amount of noise can turn the system from desynchronization to the GS state in the resonant case no matter how noise is injected into the system. In the non-resonant case, noise with intensity in a certain range is helpful in building GS only when the noise is injected to the driving system. The mechanism behind the observed phenomena is discussed.
La médicalisation des humeurs des enfants
Monzée, Joël
2015-01-01
Les enfants qui ont des comportements dérangeants ou qui souffrent de problèmes neurologiques, comme le trouble déficitaire de l’attention avec ou sans hyperactivité (TDAH), remettent en question nos moyens d’intervention pour les aider. Alors que le contexte européen tend à privilégier une intervention psychoéducative, les milieux nord-américains recourent davantage aux psychostimulants pour réduire les effets des problèmes comportementaux des enfants. Cet article aborde quelques problématiq...