WorldWideScience

Sample records for asynchronous motors

  1. Direct Torque Control of the Asynchronous Motor

    Directory of Open Access Journals (Sweden)

    Peter Girovský

    2008-05-01

    Full Text Available This contribution deals with the proposal of direct torque control (DTC of asynchronous motor (AMwith the help of fuzzy logic. The whole structure of DTC is designed in software Matlab – Simulink, the fuzzy regulator is designed with the help of Fuzzy Toolbox. The results of DTC with fuzzy regulator are compared with DTC with the help of Depenbrock method and DTC with the help of Takahashi method.

  2. Direct Torque Control of the Asynchronous Motor

    OpenAIRE

    Peter Girovský; Jaroslava Žilková; Ľubomír Cibuľa; Jaroslav Timko

    2008-01-01

    This contribution deals with the proposal of direct torque control (DTC) of asynchronous motor (AM)with the help of fuzzy logic. The whole structure of DTC is designed in software Matlab – Simulink, the fuzzy regulator is designed with the help of Fuzzy Toolbox. The results of DTC with fuzzy regulator are compared with DTC with the help of Depenbrock method and DTC with the help of Takahashi method.

  3. Considerations regarding asynchronous motor rotor parameters determination by FEM

    Directory of Open Access Journals (Sweden)

    Olivian Chiver

    2010-12-01

    Full Text Available The paper presents some considerations about asynchronous motor rotor parameters determination, using software based on finite elements method (FEM. For this, 2D magnetostatic and time harmonic analysis will be realized, at different frequencies, in case of a three phase asynchronous motor.

  4. Considerations regarding asynchronous motor rotor parameters determination by FEM

    OpenAIRE

    Olivian Chiver; Liviu Neamt; Zoltan Erdei; Eleonora Pop

    2010-01-01

    The paper presents some considerations about asynchronous motor rotor parameters determination, using software based on finite elements method (FEM). For this, 2D magnetostatic and time harmonic analysis will be realized, at different frequencies, in case of a three phase asynchronous motor.

  5. The Engine Mechanical Coordinates Measuring in the Asynchronous Motor

    Directory of Open Access Journals (Sweden)

    Dementyev Yuriy N.

    2014-01-01

    Full Text Available The article considers indirect control devices for the mechanical coordinate’s measurement of a three-phase asynchronous electric motor, which detects the temperature of the stator winding conductors and the basic frequency of stator voltage. Characteristics of mechanical coordinate’s simulation of the asynchronous motor are provided to assess the accuracy of the mechanical coordinate’s measurement in the dynamic modes.

  6. The Engine Mechanical Coordinates Measuring in the Asynchronous Motor

    OpenAIRE

    Dementyev Yuriy N.; Umurzakova Anara D.

    2014-01-01

    The article considers indirect control devices for the mechanical coordinate’s measurement of a three-phase asynchronous electric motor, which detects the temperature of the stator winding conductors and the basic frequency of stator voltage. Characteristics of mechanical coordinate’s simulation of the asynchronous motor are provided to assess the accuracy of the mechanical coordinate’s measurement in the dynamic modes.

  7. Research on DSP-based Asynchronous Motor Control Technology

    OpenAIRE

    Jun Yao; Xiangxin Qiao; Xin Wang

    2013-01-01

    The Motor in a variety of electrical transmission and position servo system occupies an extremely important position. After the DSP technology being applied to the motor control, the unification of the hardware and the flexibility of the software can be combined. Take the brushless DC motor for example, studied the mathematical model and the structure of the motor control system, also obtained the design scheme of the DSP-based asynchronous motor control system. With TI's 32 bit fixed point D...

  8. Asynchronous Torque Characteristics of VR Type Vernier Motor

    Science.gov (United States)

    Suda, Hiroshi; Matsushima, Yoshitaro; Xu, Li; Anazawa, Yoshihisa

    Recently, various types of vernier motor are developed. The VR type vernier motor is a kind of three-phase reluctance motor, and its stator has slots and distributed three-phase windings. The rotor is slotted iron core without windings. Relationship between S, R and P is S = R±2, where S and R are the numbers of stator and rotor slots per pair of poles, and the number of poles P is two. The rotor of the vernier motor moves at a sub-multiple of the angular velocity of the stator mmf. The multiplying factor is P/R. Authors had reported that the VR type vernier motors are analyzed as a three-phase reluctance motor, and have obtained the voltage equations on the γ-δ axis and expression of the torque.However, the asynchronous characteristics of the vernier motor are not clear yet. In this paper, the asynchronous characteristics of the vernier motors are analyzed with the symmetric components transformation and the commutator transformation. The voltage equations on the symmetrical co-ordinates and asynchronous and synchronous torque expression at steady state condition are obtained. The tests were performed on the trial motor. The calculated asynchronous torque has agreed well with the measured values.

  9. Research on DSP-based Asynchronous Motor Control Technology

    Directory of Open Access Journals (Sweden)

    Jun Yao

    2013-05-01

    Full Text Available The Motor in a variety of electrical transmission and position servo system occupies an extremely important position. After the DSP technology being applied to the motor control, the unification of the hardware and the flexibility of the software can be combined. Take the brushless DC motor for example, studied the mathematical model and the structure of the motor control system, also obtained the design scheme of the DSP-based asynchronous motor control system. With TI's 32 bit fixed point DSPTMS320F2812 as the core design of the hardware system, we wrote the system software, debug the motor control system and the results show that the system achieves the expected effect. The results of the research can be applied to brushless DC motor and other motor control, it will have a wide application prospects.

  10. The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

    Science.gov (United States)

    Antonovičs, Uldis; Bražis, Viesturs; Greivulis, Jānis

    2009-01-01

    The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

  11. Control of asynchronous motors. Volume 1. Modeling, vectorial control and direct torque control; Commande des moteurs asynchrones. Volume 1. Modelisation, controle vectoriel et DTC

    Energy Technology Data Exchange (ETDEWEB)

    Canudas de Wit, C. [Ecole Nationale Superieure d' Ingenieurs de Genie Chimique, ENSIGC, 31 - Toulouse (France)

    2000-07-01

    This first volume deals with the problems of control of asynchronous motors in industrial environments: industrial environment, variable speed, asynchronous motors and power supplies, modeling, direct torque control laws, control by controlled limit cycles under frequency constraints. (J.S.)

  12. ON THE ISSUE OF VECTOR CONTROL OF THE ASYNCHRONOUS MOTORS

    Directory of Open Access Journals (Sweden)

    B. I. Firago

    2015-10-01

    Full Text Available The paper considers the issue of one of the widespread types of vector control realization for the asynchronous motors with a short-circuited rotor. Of all more than 20 vector control types known presently, the following are applied most frequently: direct vector control with velocity pickup (VP, direct vector control without VP, indirect vector control with VP and indirect vector control without VP. Despite the fact that the asynchronous-motor indirect vector control without VP is the easiest and most spread, the absence of VP does not allow controlling the motor electromagnetic torque at zero velocity. This is the reason why for electric motor drives of such requirements they utilize the vector control with a velocity transducer. The systems of widest dissemination became the direct and indirect vector control systems with X-axis alignment of the synchronously rotating x–y-coordinate frame along the rotor flux-linkage vector inasmuch as this provides the simplest correlations for controlling variables. Although these two types of vector control are well presented in literature, a number of issues concerning their realization and practical application require further elaboration. These include: the block schemes adequate representation as consisted with the modern realization of vector control and clarification of the analytical expressions for evaluating the regulator parameters.The authors present a technique for evaluating the dynamics of an asynchronous electric motor drive with direct vector control and x-axis alignment along the vector of rotor flux linkage. The article offers a generalized structure of this vector control type with detailed description of its principal blocks: controlling system, frequency converter, and the asynchronous motor.The paper presents a direct vector control simulating model developed in the MatLab environment on the grounds of this structure. The authors illustrate the described technique with the results

  13. Ironless asynchronous motors with superconducting auxiliary excitation

    International Nuclear Information System (INIS)

    Describes induction motors having an outer squirrel-cage or slip-ring rotor driving the shaft, and an inner, free-running rotor with the function of compensating the reactive load of the stator. Investigates theoretically the suggestion that a superconducting inner rotor would also produce very high excitation, and enable the iron circuits to be dispensed with. (R.W.S.)

  14. Electrotechnics - AC motors. Asynchronous and brush-less motors - Lecture and exercises with solutions; Electrotechnique - Moteurs a courant alternatif. Moteurs asynchrones et brushless - Cours et problemes resolus

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, D.

    2005-07-01

    This book proposes a presentation of AC electric motors essentially based on physics and technology. Its originality consists in avoiding to use mathematical formulations (like Park's transformation). The modeling retained, which only uses magnetic momentum, magnetic fields and reluctance concepts, leads simply and naturally to the vectorial control principle. The book develops some lecture elements which includes some topics rarely considered like the dimensioning of an asynchronous motor or of a single-phase brush-less motor. Experimental results illustrate the physical phenomena described and many original problems are resolved and commented at the end of each chapter. Content: signals and systems in electrotechnics, torque and rotating magnetic fields generation, asynchronous machine in permanent regime, speed variation of the asynchronous motor, special asynchronous motors, synchronous machine in permanent regime, brush-less motor, note about step motors, note about inverters, index. (J.S.)

  15. ELECTROMAGNETIC CALCULATION OF THREE-PHASE ASYNCHRONOUS MOTORS WITH A SIX-PHASE WINDING

    OpenAIRE

    S.Yu. Polezіn; Kiryanov, V. V.; V.D. Lushchyk

    2013-01-01

    Features of electromagnetic computation of three-phase asynchronous motors with a six-phase winding in the stator are described. Experimental data on a conveyor motor with two six-phase windings are given.

  16. ELECTROMAGNETIC CALCULATION OF THREE-PHASE ASYNCHRONOUS MOTORS WITH A SIX-PHASE WINDING

    Directory of Open Access Journals (Sweden)

    S.Yu. Polezіn

    2013-02-01

    Full Text Available Features of electromagnetic computation of three-phase asynchronous motors with a six-phase winding in the stator are described. Experimental data on a conveyor motor with two six-phase windings are given.

  17. Adding effect of current displacement and magnetic circuit saturation in an asynchronous motor mathematical model

    Directory of Open Access Journals (Sweden)

    I.A. Tsodik

    2014-04-01

    Full Text Available A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.

  18. The study of transient processes in the asynchronous starting of the synchronous motor

    Directory of Open Access Journals (Sweden)

    Alexandru Bârlea

    2012-12-01

    Full Text Available Starting synchronous motors can be achieved by several ethods: starting with an auxiliary motor launch, starting in asynchronous regim, by feeding from a variable frequency source, auto-synchronization with the network.. In our case we study the transient processes in a asynchronous regim . In this case the synchronous motor is started like a squirrel cage induction motor . To start, the synchronous motor is equipped with a starting winding cage placed in the pole pieces of polar inducers; later , during the operation, this acts as a damping winding. Large synchronous motors have pole pieces made from massive polar inducers fulfilling the role of a cage winding.

  19. Speed estimation of vector controlled squirrel cage asynchronous motor with artificial neural networks

    International Nuclear Information System (INIS)

    In this paper, the artificial neural networks as a sensorless speed estimator in indirect vector controlled squirrel cage asynchronous motor control are defined. High dynamic performance power semi conductors obtainable from direct current motors can also be obtained from asynchronous motor through developments in digital signal processors (DSP) and control techniques. With using of field diverting control in asynchronous motors, the flux and moment can be controlled independently. The process of estimating the speed information required in control of vector controlled asynchronous motor without sensors has been obtained with artificial neural networks (ANN) in this study. By examining the data obtained from the experimental study concluded on the DSP application circuit, the validity and high performance of the ANN speed estimator on real-time speed estimation has been demonstrated.

  20. Calculation of mechanical characteristic for disk asynchronous motor with free rotor

    OpenAIRE

    Ерошин, Сергей Сергеевич; Мирошник, Сергей Александрович

    2012-01-01

    Taking into account the features of construction of asynchronous motor with free annular rotor analytical formulas for the calculation of its mechanical characteristic have been obtained. New features of machines with annular working tools without mechanical support are revealed

  1. A reverse mode of three-phase asynchronous motors with hexaphase windings

    OpenAIRE

    V.D. Lushchyk; S.Yu. Polezin

    2014-01-01

    A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.

  2. A reverse mode of three-phase asynchronous motors with hexaphase windings

    Directory of Open Access Journals (Sweden)

    V.D. Lushchyk

    2014-04-01

    Full Text Available A reverse operation feasibility in three-phase asynchronous motors with the stator hexaphase windings is proved. In the reverse mode, the hexaphase windings are shown to keep all their declared advantages.

  3. Research Related Electromechanical Processes in an Asynchronous Traction Motor - Asynchronous Generator with Common Shaft Based on Field Model

    Directory of Open Access Journals (Sweden)

    Yury Kazakov

    2015-01-01

    Full Text Available Creating energy efficiency traction induction motors with frequency control for hybrid drive vehicles defines practical interest for new methods of testing and simulation. Tests of these machines, it is desirable to carry out with energy recovery in the motor-generator, where a common shaft unites the machines. At present, the system simulation of motor-generator is carried out on simplified models without saturation, surface effect, jagged cores, and non-sinusoidal voltage of frequency converters. A refined interrelated mathematical model of asynchronous motor and generator operating with a common shaft, based on the theory of electrical circuits and field theory. Models allow the related modelling and study of static and dynamic modes electrical machines taking into account the saturation, skin effect, toothed cores, non-sinusoidal voltage of the frequency inverter, and variation parameters of the windings.

  4. Efficiency of three-phase asynchronous motors. Energy loss reduction by means of overdimensioning; Efficientie van driefasen asynchrone motoren. SinuMEC beperkt energieverlies door overdimensionering

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, J.; Van Dorst, C. [Hyteps, Gemert (Netherlands)

    2008-10-15

    The three phase asynchronous motor has been applied in various installations since time immemorial. Although the motor is more efficient at full mechanical load, this is not always applied efficiently. Can the efficiency of low load motors be improved or is this a utopia? The Sinusoidal Motor Controller (SinuMEC) improves efficiency, saves energy and lengthens the life span. [mk]. [Dutch] De driefasen asynchrone motor wordt sinds mensenheugenis in uiteenlopende installaties toegepast. Hoewel de motor met een volle mechanische belasting efficient is, wordt deze niet altijd efficient toegepast. Kan de efficiency van laag belaste motoren worden verbeterd of is dit een utopie? De Sinusoidal Motor efficiency controller (SinuMEC) verbetert de efficiency, bespaart energie en verlengt de levensduur.

  5. Investigation of Closed Vector Control System for Asynchronous Motor Drive of Shipboard Tow Winch

    OpenAIRE

    Н. Mehdiyev; Е. Sultanov

    2014-01-01

    The paper considers a closed vector control system for induction motor rotation speed of a shipboard tow winch. Structural schemes and transfer functions of the system at control and disturbing influences are presented in the paper. The system with asynchronous motor drive parameters of a shipboard tow winch has been investigated in the paper. It has been revealed that transit process duration of the given system is insignificant. The fact is rather important to prevent accidents in case of v...

  6. Operation Characteristics Optimization of Low Power Three-Phase Asynchronous Motors

    OpenAIRE

    I. VLAD; CAMPEANU, A.; Enache, S.; PETROPOL, G.

    2014-01-01

    Most published papers on low power asynchronous motors were aimed to achieve better operational performances in different operating conditions. The optimal design of the general-purpose motors requires searching and selecting an electric machine to meet minimum operating costs criterion and certain customer imposed restrictive conditions. In this paper, there are many significant simulations providing qualitative and quantitative information on reducing active and reactive ene...

  7. Vector control structure of an asynchronous motor at maximum torque

    Science.gov (United States)

    Chioncel, C. P.; Tirian, G. O.; Gillich, N.; Raduca, E.

    2016-02-01

    Vector control methods offer the possibility to gain high performance, being widely used. Certain applications require an optimum control in limit operating conditions, as, at maximum torque, that is not always satisfied. The paper presents how the voltage and the frequency for an asynchronous machine (ASM) operating at variable speed are determinate, with an accent on the method that keeps the rotor flux constant. The simulation analyses consider three load types: variable torque and speed, variable torque and constant speed, constant torque and variable speed. The final values of frequency and voltage are obtained through the proposed control schemes with one controller using the simulation language based on the Maple module. The dynamic analysis of the system is done for the case with P and PI controller and allows conclusions on the proposed method, which can have different applications, as the ASM in wind turbines.

  8. The Unusual Water Cooling Applied on Small Asynchronous Motor

    OpenAIRE

    Sikora, Michal; Vlach, Radek; Navrátil, Petr

    2011-01-01

    This paper is concerned with unconventional water cooling that is primarily intended for medium-power synchronous generators. A configuration of the proposed cooling was briefly described here. A way how to estimate the main thermal resistance related to the new water cooling system was presented here. A small induction motor was selected for practical verification of the proposed cooling concept. Measurements executed on this motor showed correctness of water cooling parameters design and su...

  9. MODELING OF SYMMETRIC THREE-PHASE ASYNCHRONOUS ELECTRIC MOTOR IN ASYMMETRIC CONNECTION TO NETWORK

    Directory of Open Access Journals (Sweden)

    V. I. Lukovnikov

    2016-01-01

    Full Text Available The paper shows how to solve the problem concerning reveal of changes in mathematical models and electric parameters of symmetric three-phase short-circuited asynchronous electric motors in case of their connection to single- or two-phase network in comparison with their connection to three-phase network. The uniform methodological approach permitting to generalize the known data and receive new results is offered in the paper.

  10. MODELING OF SYMMETRIC THREE-PHASE ASYNCHRONOUS ELECTRIC MOTOR IN ASYMMETRIC CONNECTION TO NETWORK

    OpenAIRE

    V. I. Lukovnikov; I. A. Rudchenko; A. V. Тurenkova

    2016-01-01

    The paper shows how to solve the problem concerning reveal of changes in mathematical models and electric parameters of symmetric three-phase short-circuited asynchronous electric motors in case of their connection to single- or two-phase network in comparison with their connection to three-phase network. The uniform methodological approach permitting to generalize the known data and receive new results is offered in the paper.

  11. Torsional stress analysis of the squirrel-cage rotor for three phase asynchronous motors

    Science.gov (United States)

    Axinte, T.; Nutu, C.

    2015-11-01

    The paper aims to determine the torsional stress occurring in the rotor's shaft of the three phase asynchronous motors for a given rotational speed of the rotor. The three phase asynchronous motor is started using the main starting variants, each variant having its own torque characteristic which produces a certain maximum shear stress. The model uses several hypotheses regarding the geometry of the domain, the dynamic behavior, the friction phenomenon and the mass of the shaft which is disregarded in a model and it is considered in a more accurate model. The maximum shear stress is produced by the shock which occurs in the starting process of the motors. This maximum stress may lead to the failure of the rotor either because it breaks, or because of the fatigue of the material produced by frequent starting of the motor. Information resulted from this study are useful for the selection of the appropriate material, of the according geometry of the design and elaboration of the specifications for the in-service use of the motor.This theoretical study will be followed by the development of more accurate models which will also include experimental studies employed to calibrate the theoretical models and to verify their accuracy.

  12. Starting-Up Impact of Powerful Asynchronous Motors Used at Gas-Compressor Units on GRID Mode

    Directory of Open Access Journals (Sweden)

    A. Hashimov

    2014-09-01

    Full Text Available The paper investigates starting-up modes of powerful asynchronous motors used at gas-compressor units which are applied for oil and gas production and transportation. Impact of motor starting-up on GRID mode for various variants of a scheme structure is considered in the paper. The paper presents investigation results taking 7 MW capacity motors as an example. The motors concerned are applied at compressor units used for oil production inAzerbaijan.

  13. Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

    Energy Technology Data Exchange (ETDEWEB)

    Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

    1997-12-31

    Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

  14. Frequency control system based on power factor control of asynchronous motor

    Institute of Scientific and Technical Information of China (English)

    MENG Qing-chun; YANG Fei-xia; REN Zhi-ling

    2005-01-01

    Deduced the relationship between the power factor (PF) and the angular frequency according to the simplified equivalent circuit of asynchronous motor, forming a power factor auto-control system. An anti-interference circuit was also introduced in the middle voltage link of inverter to avoid the shift of the optimum PF point caused by the change of the load and the reliable run of the control system was assured. The experiment results show that it has a good self-adaptation in the whole scope of speed adjustment and an obvious economization on energy while it runs under load.

  15. Fault Detection based on MCSA for a 400Hz Asynchronous Motor for Airborne Applications

    Directory of Open Access Journals (Sweden)

    Steffen Haus

    2013-01-01

    Full Text Available Future health monitoring concepts in different fields of engineering require reliable fault detection to avoid unscheduled machine downtime. Diagnosis of electrical induction machines for industrial applications is widely discussed in literature. In aviation industry, this topic is still only rarely discussed.A common approach to health monitoring for electrical induction machines is to use Motor Current Signature Analysis (MCSA based on a Fast Fourier Transform (FFT. Research results on this topic are available for comparatively large motors, where the power supply is typically based on 50Hz alternating current, which is the general power supply frequency for industrial applications.In this paper, transferability to airborne applications, where the power supply is 400Hz, is assessed. Three phase asynchronous motors are used to analyse detectability of different motor faults. The possibility to transfer fault detection results from 50Hz to 400Hz induction machines is the main question answered in this research work. 400Hz power supply frequency requires adjusted motor design, causing increased motor speed compared to 50Hz supply frequency. The motor used for experiments in this work is a 800W motor with 200V phase to phase power supply, powering an avionic fan. The fault cases to be examined are a bearing fault, a rotor unbalance, a stator winding fault, a broken rotor bar and a static air gap eccentricity. These are the most common faults in electrical induction machines which can cause machine downtime. The focus of the research work is the feasibility of the application of MCSA for small scale, high speed motor design, using the Fourier spectra of the current signal.Detectability is given for all but the bearing fault, although rotor unbalance can only be detected in case of severe damage level. Results obtained in the experiments are interpreted with respect to the motor design. Physical interpretation are given in case the results differ

  16. Relay system for phasing rotating disk selector with drive from asynchronous electric motor

    International Nuclear Information System (INIS)

    Regulating system is described which ensures rotation of a massive disk selector synphaseally with a rotating reactivity modulator in a pulse reactor. Unlike the proportional regulating principle and using d.c. motor commonly utilized in solving similar problems, the given system involves an asynchronous short-circuited electric motor and a relay regulation principle. Thyristor control provides sufficiently simple realization of two selector acceleration modes (strong and weak acceleration) and two retardation modes (strong and weak braking). The mode switch-over moments are due to the regulated magnitude and its product. The given system is simple in maintenance, and has low sensitivity to oscillations in circuit voltage. In an 80-200 mc range of the selector period, the mean-square value of the displacement angle between the selector and reactor is at least +-1 deg

  17. PID Neural Network Based Speed Control of Asynchronous Motor Using Programmable Logic Controller

    Directory of Open Access Journals (Sweden)

    MARABA, V. A.

    2011-11-01

    Full Text Available This paper deals with the structure and characteristics of PID Neural Network controller for single input and single output systems. PID Neural Network is a new kind of controller that includes the advantages of artificial neural networks and classic PID controller. Functioning of this controller is based on the update of controller parameters according to the value extracted from system output pursuant to the rules of back propagation algorithm used in artificial neural networks. Parameters obtained from the application of PID Neural Network training algorithm on the speed model of the asynchronous motor exhibiting second order linear behavior were used in the real time speed control of the motor. Programmable logic controller (PLC was used as real time controller. The real time control results show that reference speed successfully maintained under various load conditions.

  18. General-purpose stepping motor-encoder positioning subsystem with standard asynchronous serial-line interface

    International Nuclear Information System (INIS)

    A general-purpose mechanical positioning subsystem for open-loop control of experiment devices which have their positions established and read out by stepping motor-encoder combinations has been developed. The subsystem is to be used mainly for experiments to be conducted at the National Synchrotron Light Source at Brookhaven National Laboratory. The subsystem unit has been designed to be compatible with a wide variety of stepping motor and encoder types. The unit may be operated by any device capable of driving a standard RS-232-C asynchronous serial communication line. An informal survey has shown that several experiments at the Light Source will use one particular type of computer, operating system, and programming language. Accordingly, a library of subroutines compatible with this combination of computer system elements has been written to facilitate driving the positioning subsystem unit

  19. Operation Characteristics Optimization of Low Power Three-Phase Asynchronous Motors

    Directory of Open Access Journals (Sweden)

    VLAD, I.

    2014-02-01

    Full Text Available Most published papers on low power asynchronous motors were aimed to achieve better operational performances in different operating conditions. The optimal design of the general-purpose motors requires searching and selecting an electric machine to meet minimum operating costs criterion and certain customer imposed restrictive conditions. In this paper, there are many significant simulations providing qualitative and quantitative information on reducing active and reactive energy losses in motors, and on parameters and constructive solution. The optimization study applied the minimal operating costs criterion, and it took into account the starting restrictive conditions. Thirteen variables regarding electromagnetic stresses and main constructive dimensions were considered. The operating costs of the optimized motor decreased with 25.6%, as compared to the existing solution. This paper can be a practical and theoretical support for the development and implementation of modern design methods, based on theoretical and experimental study of stationary and transient processes in low power motors, to increase efficiency and power factor.

  20. Static Frequency Converter with RNSIC Converter and Double Branch Inverter for Supplying Three-Phase Asynchronous Motors

    OpenAIRE

    Lazar, G. A.; ALEXA, D.; Lazar, A.; BUZATU, N. R.; MOISA, M.

    2010-01-01

    The paper presents the design and analysis of a three-phase static converter, composed of a Rectifier with Near Sinusoidal Input Currents (RNSIC), which ensures the DC bus voltage level for a three phase Incomplete Bridge Inverter (IBI), used to drive an asynchronous motor. The proposed circuit has a low input current harmonic content, can ensure the load overcurrent protection and has a better reliability. The converter can be designed to provide any required output maximum power under a ...

  1. Hybrid EEG-fNIRS Asynchronous Brain-Computer Interface for Multiple Motor Tasks.

    Directory of Open Access Journals (Sweden)

    Alessio Paolo Buccino

    Full Text Available Non-invasive Brain-Computer Interfaces (BCI have demonstrated great promise for neuroprosthetics and assistive devices. Here we aim to investigate methods to combine Electroencephalography (EEG and functional Near-Infrared Spectroscopy (fNIRS in an asynchronous Sensory Motor rhythm (SMR-based BCI. We attempted to classify 4 different executed movements, namely, Right-Arm-Left-Arm-Right-Hand-Left-Hand tasks. Previous studies demonstrated the benefit of EEG-fNIRS combination. However, since normally fNIRS hemodynamic response shows a long delay, we investigated new features, involving slope indicators, in order to immediately detect changes in the signals. Moreover, Common Spatial Patterns (CSPs have been applied to both EEG and fNIRS signals. 15 healthy subjects took part in the experiments and since 25 trials per class were available, CSPs have been regularized with information from the entire population of participants and optimized using genetic algorithms. The different features have been compared in terms of performance and the dynamic accuracy over trials shows that the introduced methods diminish the fNIRS delay in the detection of changes.

  2. STRUCTURAL RELIABILITY OF TRACTION INVERTER FOR MULTI-SYSTEM ELECTRIC LOCOMOTIVE WITH ASYNCHRONOUS TRACTION MOTORS

    Directory of Open Access Journals (Sweden)

    A. M. Muha

    2009-04-01

    Full Text Available In the article the structural reliability of different variants of structured schemes of the steady-state converter for traction drive of promising multi-system electric locomotives with asynchronous traction engines is compared.

  3. Static Frequency Converter with RNSIC Converter and Double Branch Inverter for Supplying Three-Phase Asynchronous Motors

    Directory of Open Access Journals (Sweden)

    LAZAR, G. A.

    2010-08-01

    Full Text Available The paper presents the design and analysis of a three-phase static converter, composed of a Rectifier with Near Sinusoidal Input Currents (RNSIC, which ensures the DC bus voltage level for a three phase Incomplete Bridge Inverter (IBI, used to drive an asynchronous motor. The proposed circuit has a low input current harmonic content, can ensure the load overcurrent protection and has a better reliability. The converter can be designed to provide any required output maximum power under a desired DC link bus voltage.

  4. Simulation of asynchronous modes of synchronous motors with capacitors in the excitation circuit

    OpenAIRE

    Malyar, V. S.; Malyar, A. V.; I. A. Dobushovska

    2012-01-01

    Розглядається проблема розрахунку асинхронних режимів синхронних двигунів з конденсаторами в обмотці збудження. Задача розв'язується як крайова для нелінійної системи диференціальних рівнянь електричної рівноваги, в яких потокозачеплення контурів обчислюються шляхом розрахунку магнітного поля двигуна на основі теорії магнітних кіл. A problem of calculating asynchronous modes of synchronous motors with capacitors in the excitation circuit is considered. The problem is solved as a boundary o...

  5. Efficient operation of asynchronous motors - Final report; Effizienter Betrieb von Asynchronmotoren - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Beeli, N.; Jenni, F.

    2010-10-15

    Research has shown that the reduction of energy losses in electrical machines offers an enormous saving potential. The largest share of these losses is represented by induction motors in the medium power range. A significant fraction of these losses could be minimized by using modern frequency converters instead of traditional drive systems. However, even when operated with converters, the efficiency of these machines is still not optimal: By implementing an intelligent control scheme which involves a reduction in the magnetizing current, a significant improvement in efficiency can be achieved. Theoretical studies of the economical potential were conducted with and without the iron saturation taken into account. The behavior of the machines in the two cases of operation was described by numerical simulation. Two control algorithms that could be used in a converter have been developed: One utilizing a typical control methodology (constant flux in the machine as a reference) and another designed for optimal performance. The results show that an economical potential of up to 643 GWh per year is possible in Switzerland for all asynchronous machines, which corresponds to 4% of the total power consumption of these machines in Switzerland. With a price of 0.15 CHF/kWh, this represents a saving of approximately 95 million CHF. At this stage, it should be emphasized that this potential can be exploited provided that each machine is already equipped with a frequency converter. Converters with optimized performance are available from some manufacturers. Further investigation was required to determine if the measured savings correspond to the theoretical results. Thus, three converters have been measured in the laboratory using a controlled experiment. It was found that these saving options are effective only for non-dynamic regimes and that the algorithms are not yet ideal for torques below 10% of nominal. The reason for these results are unclear, as the algorithms used are

  6. Analysis of Current Harmonics in 3kV DC Catenary Caused by Specific Current Harmonics of an Asynchronous Motor

    Science.gov (United States)

    Lewandowski, Mirosław

    2010-01-01

    The mathematical model of vehicle supply system as well as the mathematical model of main circuit of locomotive with asynchronous motors have been described in this article. The necessity of analysis of disturbances caused by distorted current run of drive motors emerged together with the introduction of high power vehicles with power electronic converters. Analysis of the compatibility of traction high current circuits with circuits of the signal and traffic control systems requires the knowledge of current spectrum in a catenary, which has been taken by a vehicle. The author has described the algebraic method of calculating of the spectrum amplitudes in a catenary. It does not require laborious and time-consuming simulations of a system, which considerably decreases preliminary costs of designation and dimensioning of a vehicle drive system.

  7. Asynchronous recruitment of low-threshold motor units during repetitive, low-current stimulation of the human tibial nerve

    Directory of Open Access Journals (Sweden)

    Jesse eDean

    2014-12-01

    Full Text Available Motoneurons receive a barrage of inputs from descending and reflex pathways. Much of our understanding about how these inputs are transformed into motor output in humans has come from recordings of single motor units during voluntary contractions. This approach, however, is limited because the input is ill-defined. Herein, we quantify the discharge of soleus motor units in response to well-defined trains of afferent input delivered at physiologically-relevant frequencies. Constant frequency stimulation of the tibial nerve (10-100 Hz for 30 s, below threshold for eliciting M-waves or H-reflexes with a single pulse, recruited motor units in 7/9 subjects. All 25 motor units recruited during stimulation were also recruited during weak (<10% MVC voluntary contractions. Higher frequencies recruited more units (n=3/25 at 10 Hz; n=25/25 at 100 Hz at shorter latencies (19.4±9.4 s at 10 Hz; 4.1±4.0 s at 100 Hz than lower frequencies. When a second unit was recruited, the discharge of the already active unit did not change, suggesting that recruitment was not due to increased synaptic drive. After recruitment, mean discharge rate during stimulation at 20 Hz (7.8 Hz was lower than during 30 Hz (8.6 Hz and 40 Hz (8.4 Hz stimulation. Discharge was largely asynchronous from the stimulus pulses with time-locked discharge occurring at an H-reflex latency with only a 24% probability. Motor units discharged after the stimulation ended in 89% of trials, although at a lower rate (5.8 Hz than during the stimulation (7.9 Hz. This work supports the idea that the afferent volley evoked by repetitive stimulation recruits motor units through the integration of synaptic drive and intrinsic properties of motoneurons, resulting in physiological recruitment which adheres to Henneman's size principle and results in relatively low discharge rates and asynchronous firing.

  8. Improving the energy indicators of thyristor electric drive with asynchronous short-circuited motor of a deep pump unit by negative feedback

    Energy Technology Data Exchange (ETDEWEB)

    Aliyev, E.S.

    1983-01-01

    At the department of electric drive and automation of industrial units of the M. Azizbekov Azerbaijan Institute of Petrochemistry a system was developed for automated thyristor electric drive of alternating current with asynchronous short-circuited electric motor for smooth regulation of the output of a deep-pump unit, which at the same time makes it possible to improve the energy efficiency of the electric drive of the pumping unit with quasi steady-state mode of changing the voltage on the motor stator according to the load by using negative feedback for the rotation frequency of the motor.

  9. Application of Z-source inverter in the asynchronous motor%Z源逆变器在异步电动机中的应用

    Institute of Scientific and Technical Information of China (English)

    朱红; 祝龙记; 夏若飞

    2014-01-01

    In recent years,the asynchronous motor drive of indirect field-oriented control (IFOC)is widely used in high performance drive systems because of its high efficiency,high stable performance and power factor. In this paper,the IFOC technology is used to control the size of the speed of asynchronous motor,and the Z-source inverter is used,namely putting a pair of LC network in front of the inverter main circuit,to achieve the function of boost or buck the voltage and improve the efficiency of asynchronous motor by controlling the direct duty ratio.%近年来,间接磁场定向控制(IFOC)的异步电机驱动由于其效率高、稳定性能强及功率因数高,被广泛应用在高性能驱动系统中。本文采用IFOC技术来控制异步电机的速度大小,并使用Z源逆变器,即在逆变器主电路前加上一对阻抗(LC)网络,通过控制直通占空比,可以实现升/降压功能、提高异步电机的效率。

  10. Fault Detection based on MCSA for a 400Hz Asynchronous Motor for Airborne Applications

    OpenAIRE

    Steffen Haus; Heiko Mikat; Martin Nowara; Surya Teja Kandukuri; Uwe Klingauf; Matthias Buderath

    2013-01-01

    Future health monitoring concepts in different fields of engineering require reliable fault detection to avoid unscheduled machine downtime. Diagnosis of electrical induction machines for industrial applications is widely discussed in literature. In aviation industry, this topic is still only rarely discussed.A common approach to health monitoring for electrical induction machines is to use Motor Current Signature Analysis (MCSA) based on a Fast Fourier Transform (FFT). Research results on th...

  11. The development of mathematical model for the study of electromagnetic interference from the traction converters with asynchronous motor

    OpenAIRE

    V. I. Shcheka; HAVRYLIUK V.I.

    2010-01-01

    The mathematical modeling and circuit simulation of asynchronous propulsion drive unit with converters on IGBT transistors have been made. The possible noises appearing during drive’s operation have been determined. The spectral composition of phase current of the asynchronous engine has been obtained.

  12. THE DEVELOPMENT OF MATHEMATICAL MODEL FOR THE STUDY OF ELECTROMAGNETIC INTERFERENCE FROM THE TRACTION CONVERTERS WITH ASYNCHRONOUS MOTOR

    Directory of Open Access Journals (Sweden)

    V. I. Shcheka

    2010-01-01

    Full Text Available The mathematical modeling and circuit simulation of asynchronous propulsion drive unit with converters on IGBT transistors have been made. The possible noises appearing during drive’s operation have been determined. The spectral composition of phase current of the asynchronous engine has been obtained.

  13. 交流异步电动机调速系统控制策略综述%Review of AC asynchronous motor speed control strategy

    Institute of Scientific and Technical Information of China (English)

    丁辉; 胡协和

    2011-01-01

    为了更精确地实现交流异步电动机调速,基于交流异步电动机的数学模型论述异步电动机变压变频(VVVF)调速系统的各种控制策略.总结早期的基于异步电机稳态模型的控制策略,介绍3种较成熟的基于动态模型的控制策略,分析现代控制理论在交流异步电动机调速系统中的应用,展望交流调速控制策略的发展方向.传统的控制策略在工业现场中的应用已经较为成熟,各种现代控制策略和先进控制算法则有广阔的发展前景.%Variable voltage variable frequency (VVVF) speed control strategies were researched based on the mathematical model of alternating current (AC) asynchronous motor in order to achieve more accurate speed control of AC induction motor. The early control methods of induction motor based on the steady-state model were simply summarized. Three mature control schemes based on the dynamic model were introduced. The application of modern control theory in AC asynchronous motor speed control system was analyzed. Finally, the future development direction of AC speed control strategy was given. Traditional strategies were maturely utilized in industrial field, but the modern control theory and advanced control algorithms still have vast potential for future development.

  14. General analysis of the three-phase asynchronous motor with spiral sheet rotor: operation, parameters and characteristic values

    OpenAIRE

    Mujal Rosas, Ramón María; Orrit Prat, Jordi

    2010-01-01

    The objectives of this article arise through the investigation of a motor with a high starting torque although with limited intensities, weak intensity variations depending on the load, controlled losses in no-load tests, and an acceptable performance in steady state and with a good response in transient periods. All these requirements would have to be obtained without the help of power electronics, in this way the motor would be more robust, longer lasting and without th...

  15. Vector control of a single-phase induction motor with optimal supply; Alimentation optimisee d'une machine asynchrone diphasee a commande vectorielle

    Energy Technology Data Exchange (ETDEWEB)

    Vandecasteele, F.

    1998-07-01

    This work presents a power supply structure for a dissymmetrical two-phase asynchronous machine and proposes a speed control strategy. In the first chapter, the modeling of the two-phase asynchronous machine leads to a dynamical model which is necessary for the simulation of the process. The study of the magneto-motive forces has permitted to propose a stator currents law in which the electromagnetic torque pulses are neglected. The equivalence between the behaviour of the dissymmetrical machine with a symmetrical machine is demonstrated. The second chapter presents the 3/2 converter. A causal informatory graphic tool allows the modeling of this structure and the elaboration of its control. The unbalanced characteristic of the application is at the origin of the power limitation threw the converter. Thus, solutions are proposed to define the best control of switches in order to ensure an optimum energy transfer. The suppression of the vibratory torque requires to respect a currents law. Thus, their control in the natural reference frame of the coils must be perfect. A corrector structure based on the resonance phenomenon is proposed in chapter 3. Its synthesis, control and regulation qualities and robustness are demonstrated and make it the best solution for the follow up of the alternative trajectory. In chapter 4, the converter and the two-phase motor are joined together. The equivalence between a real machine and a symmetrical machine has led to the development of an original vectorial control. The control of currents is made in the natural framework of the coils thanks to the resonant corrector. This strategy allows an efficient control of the speed. Chapter 5 proposes a 3/2 converter with a capacitive mid-point. A switches cell connected to the network is used to maintain the correct voltage values at the capacitor terminals. The control of this switching cell, based on an average power model, allows to reach a quasi-unitary power factor for the installation

  16. Procedimiento para el cálculo de los parámetros de un modelo térmico simplificado del motor asincrónico Parameter estimation procedure for an asynchronous motor simplified thermal model

    Directory of Open Access Journals (Sweden)

    Julio R Gómez Sarduy

    2011-06-01

    Full Text Available En este trabajo se presenta un método para estimar las conductancias y capacitancias de un modelo térmico simplificado del motor asincrónico, utilizando una técnica de baja invasividad. El procedimiento permite predecir el incremento de temperatura del estator del motor asincrónico, tanto para régimen dinámico como en condiciones de estabilidad térmica. Se basa en la estimación paramétrica mediante un modelo de referencia, utilizando como optimizador un algoritmo genético (AG. Se logra en definitiva obtener los parámetros del modelo térmico con un ensayo más sencillo que lo requerido por otros métodos experimentales complejos o cálculos analíticos basados en datos de diseño. El procedimiento propuesto se puede llevar a cabo en condiciones propias de la industria y resulta atractivo su empleo en el análisis de calentamiento de estas máquinas. El método se valida a partir de un estudio de caso reportado en la literatura y se aplica a un caso real en la industria, lográndose una buena precisión.In this paper, an asynchronous motor simplified thermal model method for conductances and capacitances estimation is presented. A low invasive technique is used. The developed procedure allows the stator temperature rise prediction, not only for dynamic regimes, but also in case of thermal stability. A parametric estimation is done through a reference model, using a genetic algorithm (GA as optimizing method. The thermal model parameters are finally obtained with an easer experimental work, than the required by other complex experimental methods or by analytical calculations based on design data. The proposed procedure can be carry out in the particular conditions of industrial environment. Its application is specially useful for asynchronous machine thermal analysis. Using the data of a study case reported in literature, the method validation is done, and is applied in an industrial real case, with good precision resulted from it.

  17. 三相异步电动机的杂散损耗研究%Research on Stray Loss of Three-Phase Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    宁榕; 李巧莲; 黄坚

    2014-01-01

    Efficiency and temperature rise of motor are affected by stray loss, whose size magnitude is connected with the design parameters of the motor and the quality of the processing technology and so on. Inhibition of stray loss is an effective measure to increase efficiency and reduce cost. The surface loss, tooth pulse vibration, rotor harmonic loss and transverse leakage current loss were analyzed. Based on the selection of design parameters, such as sine winding, slot coordination, air gap length, cast aluminum process, the measures to reduce stray loss was analyzed. The measures were applied to the product development of ultra high efficiency three-phase asynchronous motor. The result shows that the efficiency index has reached new national standard, and achieved IE3 ultra high efficiency standards level, and high frequency stray loss is effectively restrained, and the manufacturing cost is reduced.%杂散损耗影响电机的效率和温升,其大小与电动机的设计参数、加工工艺质量等因素有关。抑制杂散损耗是增效率、降成本的有效措施。分析了表面损耗、齿部脉振损耗、转子谐波损耗、横向泄漏电流损耗,并针对正弦绕组、槽配合、气隙长度、铸铝工艺的设计参数选择,分析了降低杂散损耗的措施。该措施应用到超高效三相异步电动机的产品开发,效率指标达到了新国家标准,达到了IE3超高效率标准等级,有效抑制高频杂散损耗,降低了制造成本。

  18. Handbook of asynchronous machines with variable speed

    CERN Document Server

    Razik, Hubert

    2013-01-01

    This handbook deals with the asynchronous machine in its close environment. It was born from a reflection on this electromagnetic converter whose integration in industrial environments takes a wide part. Previously this type of motor operated at fixed speed, from now on it has been integrated more and more in processes at variable speed. For this reason it seemed useful, or necessary, to write a handbook on the various aspects from the motor in itself, via the control and while finishing by the diagnosis aspect. Indeed, an asynchronous motor is used nowadays in industry where variation speed a

  19. Simulation research of matrix converter and asynchronous motor control system%矩阵变换器-异步电机矢量控制系统仿真研究

    Institute of Scientific and Technical Information of China (English)

    姜香菊; 刘二林

    2012-01-01

    Space vector pulse width modulation of matrix converter and rotor field oriented vector control of asynchronous motor are combined, and the paper researchs combination strategy for vector control of the matrix converter and rotor field oriented vector control of asynchronous motor. Input voltage and current of matrix converter are simulated by MATLAB, at the same time, no-load starting torque and speed waveform and the electrical load torque waveform of motor are simulated. The simulation results show that the combined control strategy for matrix converter-asynchronous vector control system has good speed performance, and has the advantage of a AC-DC-AC voltage type PWM variable frequency speed regulation system.%研究了将矩阵变换器的空间矢量脉宽调制与异步电机转子磁场定向矢量控制相结合的组合控制策略,并采用MATLAB对矩阵变换器的输入电压波形、输入电流波形、电机空载启动转矩波形、电机空载启动转速波形以及在电机突加负载时的转矩波形等进行仿真.仿真结果表明了采用组合控制策略的矩阵变换器-异步电机矢量控制系统具备良好的调速性能,并且较交-直-交电压型PWM变频调速系统而言具有更多的优势.

  20. REACTIVE POWER COMPENSATION IN ASYNCHRONOUS ELECTRIC DRIVES

    Directory of Open Access Journals (Sweden)

    V.S. Malyar

    2013-10-01

    Full Text Available A problem of calculating capacity of cosine capacitors for individual compensation of reactive power in asynchronous electric drives in stationary and transient operation modes is considered. The algorithm introduced employs a high-adequacy mathematical model of asynchronous motor developed on the theory of representing vectors which takes into account both the magnetic core saturation and the current displacement in the rotor bars.

  1. Characteristics of Three Phase Asynchronous Motor and Analysis of Variable Frequency Speed Regulation%三相异步电动机特性及其变频调速分析

    Institute of Scientific and Technical Information of China (English)

    杨雪林

    2016-01-01

    The motor is currently used the most extensive electrical transmission device, the three-phase asynchronous motor, using electrical theory, in-depth analyzes its equivalent circuit, the rotor circuit, referred to the stator side, forming a complete unity circuit, analyzes the various equations based on equivalent circuit, motor energy transfer process is embodied by the equation, mapped the working characteristic curve according to the equation. All motor control method is different, for three phase asynchronous cage motor, this paper analyzes the modern most popular drive system, variable frequency drive, analyzes the excellent characteristics and attention of frequency converter application.%电动机是目前应用最为广泛的电气传动装置,针对三相异步电动机,利用电工理论,深入分析了其等值电路,将转子回路折算到定子侧,形成一个完整的统一回路,在等值电路的基础上分析了各种方程式,方程式对电动机的能量传递过程有了深刻直观的体现,根据方程式绘制了工作特性曲线。各种电动机控制方法大有不同,针对三相异步鼠笼型电动机,本文分析了现代最流行的驱动系统,即变频驱动,分析了变频器应用时的相关注意事项及变频调速的优良特性。

  2. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    OpenAIRE

    Grigorash O. V.; Bogatyrev N. I.; Hitskova A. O.

    2015-01-01

    A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the m...

  3. 三相笼型异步电动机减压起动控制方法综述%Study on Approach of Starting Control by Pressure Reduction of Three-phase Cage-type Asynchronous Motors

    Institute of Scientific and Technical Information of China (English)

    叶新颖

    2015-01-01

    Due to desirable properties of simple structure, solidity and durability, high adaptability and efficient operation, three-phase cage-type asynchronous motor is extensively applied in the fields of industrial and agricultural production, national defense and scientific and technological research. From the perspective of starting control by pressure reduction, the author comprehensively analyzes the quantitative relation of the approaches of the control, respectively illuminates their characteristics and application range and further forecasts the future development trend of approach of motor starting control. The study in this paper is of great significance for the improvement of control circuit performance, motor service life prolongation, utilizing motor performance in energy-efficient manner and remarkable reduction of impact force imposed on power grid.%三相笼型异步电动机由于具有结构简单,坚固耐用,适应性强,运行高效等良好性能,被广泛应用于工农业生产、国防建设、科学技术研究等各个领域。本论文从三相笼型异步电动机的减压起动控制综合分析了减压起动控制方法的控制过程中数量关系并阐述了其各自的特点及适用范围,且对电动机起动控制方法未来的发展趋势做了进一步探讨与展望,对高效利用电动机性能、延长其使用寿命及有效减弱对电网的冲击力等方面的探究具有重要的意义。

  4. Compositional asynchronous membrane systems

    Institute of Scientific and Technical Information of China (English)

    Cosmin Bonchis; Cornel Izbasa; Gabriel Ciobanu

    2007-01-01

    This paper presents an algorithmic way of building complex membrane systems by coupling elementary membranes. Its application seems particularly valuable in the case of asynchronous membrane systems, since the resulting membrane system remains asynchronous. The composition method is based on a handshake mechanism implemented by using antiport rules and promoters.

  5. 基于强跟踪滤波算法的异步电机参数自适应无速度传感器控制%Parameter Adaptation Sensorless Control of Asynchronous Motor Based on Strong Track Filter

    Institute of Scientific and Technical Information of China (English)

    陆可

    2011-01-01

    在异步电机四阶模型的基础上增加机械和转矩方程,并引入负载转矩和转子电阻为状态变量,得到七阶非线性模型.利用强跟踪滤波(STF)算法实现电机状态和转子电阻的同时估计,通过仿真比较了STF和扩展Kalman滤波(EKF)算法的估计性能.结果表明,STF算法能有效估计电机状态及辨识转子电阻,并且具有比EKF算法更理想的估计性能,同时能满足极低速和零速下的估计要求,从而在电机的整个工作范围内实现转子电阻自适应的状态估计.%The equations of machine and torque were added to the fourth-order model of asynchronous motor.A seventh-order nonlinear model was obtained via increasing load torque and rotor resistance as state variables.The motor states and the rotor resistance were estimated simultaneously using strong track filter (STF).Computer simulations were performed to compare the estimation performance between STF and EKF.The results illustrated that STF could estimate the motor states and the rotor resistance effectively, and its performance was more perfect than EKF' s.STF could also satisfy the estimation request running at very low and zero speed, thus it could realize the states estimation with rotor resistance adaptation in the whole operation range.

  6. Speed Sensorless Vector Control of Asynchronous Motor Based on UKF%基于UKF算法的异步电机无速度传感器矢量控制系统

    Institute of Scientific and Technical Information of China (English)

    廖晓文; 陈政石

    2011-01-01

    针对异步电机无速度传感器矢量控制系统的转速、磁链估计问题,提出一种基于无轨迹卡尔曼滤波(UKF)的状态估计算法.为避免常用的对称采样方法仅适用于处理高斯噪声并且sigma点多带来的计算量大问题,依据UT变换理论,采用最小偏度单形采样方法,减少了近1/3的计算量.仿真结果表明,所提出的基于最小偏度采样的UKF估计器能够准确地估计转子磁链、转速.%Concerning the speed and flux estimation problem of speed sensorless vector control of asynchronous motor, a state estimation algorithm based on Unscented Kalman Filter is proposed. Symmetrical sampling strategy is common used but not showed good performance while dealing with non-Gaussian noise, and the large number of sigma points causes reasonable computation load. In the paper, ninimal skew simplex sampling is adopted according to UT transformation theory, as a result, nearly 1/3 computation load is reduced. Simulation results show that the UKF estimator based on the minimal skew simplex sampling can estimate flux and rotor speed precisely.

  7. 基于MATLAB/Simulink的异步电机控制系统建模与仿真%Modeling and simulation of asynchronous motor control system based on MATLAB/Simulink

    Institute of Scientific and Technical Information of China (English)

    孟朝霞; 任一峰

    2012-01-01

    In this paper, based on the means of asynchronous motor' s rotor flux-oriented vector control,and the shortcomings that rotor flux is influenced by motor parameters in magnetic linkage closed loop, this article adopts vector control scheme of magnetic flux opended loop.By modular thought,the functional modules of the opening magnetic flux loop of vector control system is modeled in MATLAB/Simulink. Through the organic integration of each functional modules, a simulation model of vector control system is modeled. The results show that the system has a good dynamic performance and the anti-interference ability,so the feasibility and effectiveness of the modeling method is validated. The results also provides a theoretical foundation for design and debug of actual motor control system.%本文在基于转子磁链定向的异步电机矢量控制理论基础上,针对磁链闭环的矢量控制系统中转子磁链易受电机参数影响的不足,提出了转子磁链开环的矢量控制方案。利用模块化思想,在MATLAB/Simulink建立磁链开环的矢量控制系统的各个功能模块,然后对各个功能模块进行有机的整合,构成矢量控制系统的仿真模型;仿真结果表明该系统具有良好的动态性能和抗干扰能力,进而验证了该控制系统设计的可行性和有效性,为实际电机控制系统的设计和调试奠定了理论基础。

  8. 三相异步电机制动方式瞬态过程仿真分析研究%Simulation study on transient process of 3-phase asynchronous motor braking

    Institute of Scientific and Technical Information of China (English)

    朱春鸯; 周政新

    2013-01-01

    In order to get some constrains and transient process of asynchronous motor braking,by Matlab/Simulink environment,and based on motor simulation model of the mathematic model of d-q coordination and breakers and resistors of Simulink tools,simulation controlling model of motor braking is gotten.The simulation result shows that this method can get the optimization parameters of exhausted-braking,reserve-connection braking,regenerative braking through repeatly modifying voltage and resistors parameters,and so on,what's more,the transient process alteration of rotator and stator current,rotation speed and retarding torque is analyzed.Simulink results can guide us for special project application,at the same time,this method of building simulation model also supply theory into practice for building model of control running of motor and other braking model.%为获取电机制动方式实现的约束条件及制动过程的瞬态特性分析,运用Matlab/Simulink仿真环境平台,应用基于d-q坐标下数学模型建立的电机仿真模型及Simulink工具箱中断路器、阻抗等工具搭建电机制动方式仿真控制模型.通过反复调节模型中模块参数,改变电源电压或负载大小、回路断开闭合的时间等,找到能耗制动、电源反接制动、倒拉反接制动、回馈制动控制回路最优参数,并能直观观察分析比较其制动过程中的定转子瞬态电流、速度及其制动转矩变化的暂态过程,由此确定电机性能为具体的工程案例应用提供实践依据,同时,建立的仿真模型方法也为电机控制运行及其它制动方式建模提供理论指导.

  9. Research on Asynchronous Motor Featured with High Efficiency, High Power Density and Low Noise%高效高功率密度低噪声电机研究

    Institute of Scientific and Technical Information of China (English)

    周玲慧; 向善海; 陈华

    2015-01-01

    Taking the development process of a 3 550 kW 6 kV 6-pole asynchronous motor featured with high efficiency, high power density and low noise as an example, analyzed the approaches and methods to increase the power density and decrease the noise from the aspects of insulation system design, ventilation and heat dissipation design, optimization of electromagnetic design, structure design and manufacturing process, and investigated the influences by related factors on the temperature rise of the motor based on the simulation and test results. Targets were defined for developing this motor of high efficiency, high power density and low noise. Compared with the corresponding parameters of the similar products of the major international electric machines manufactures, test data showed that the defined targets were well achieved of this motor.%以一台3550 kW、6 kV、6极高效高功率密度低噪声电机的研制为例,从绝缘系统和通风散热系统设计、电磁设计、结构设计和加工工艺等方面,分析了提高电机功率密度和降低噪声的途径和方法。结合相关仿真与样机试验,分析了几个相关因素对电机温升的影响。提出了该型号高效高功率密度低噪声电机的研制目标。给出了样机试制与型式试验结果,结合国外先进电机制造企业的相关产品参数,说明了该型号高效高功率密度低噪声电机的研制取得了成功,达到了国际先进水平。

  10. 异步电机三维电磁场及温度场耦合仿真分析∗%Coupling Simulation of 3 D Electromagnetic Field and Thermal Field of Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    陈华毅; 杨明发

    2015-01-01

    Deals with 3D temperature estimation for the asynchronous motor Y100L2-4. According to the structure characteristics and electromagnetic parameters, the thermal fields of steady state operation with rated load has been analyzed to extract the heat source of the motor, as the foundation of the steady temperature distribution. The heat dissipation coefficient of each part in motor and the equivalent heat transfer coefficient of air gap between the rotor and stator were analyzed. According to the boundary condition and the equivalent hypothesis and material properties of the motor, the temperature field was derive by One-way coupled simulation of finite element software, based on the simulation results of electromagnetic field. the simulation results have higher accuracy was verify by comparing with the experimental data.%以型号为Y100L2-4的异步电机为对象,建立了三维有限元模型。根据样机的结构特征和电磁参数,仿真计算出了样机额定负载下运行至稳态的电磁场,用以提取较为精确的发热源,进而计算其稳态温度分布。分析了电机各部分散热系数、定转子间气隙的等效传热系数,依据电机的边界条件、等效假设和材料属性,以电磁场仿真结果为基础,利用有限元软件单向耦合出相应的温度场分布图。最后通过与试验数据对比,验证仿真结果有更高的准确性。

  11. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  12. Asynchronized synchronous machines

    CERN Document Server

    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

  13. Asynchronous Variational Contact Mechanics

    CERN Document Server

    Vouga, Etienne; Tamstorf, Rasmus; Grinspun, Eitan

    2010-01-01

    An asynchronous, variational method for simulating elastica in complex contact and impact scenarios is developed. Asynchronous Variational Integrators (AVIs) are extended to handle contact forces by associating different time steps to forces instead of to spatial elements. By discretizing a barrier potential by an infinite sum of nested quadratic potentials, these extended AVIs are used to resolve contact while obeying momentum- and energy-conservation laws. A series of two- and three-dimensional examples illustrate the robustness and good energy behavior of the method.

  14. Redundant Asynchronous Microprocessor System

    Science.gov (United States)

    Meyer, G.; Johnston, J. O.; Dunn, W. R.

    1985-01-01

    Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

  15. Asynchronous P300 BCI

    DEFF Research Database (Denmark)

    Panicker, Rajesh; Puthusserypady, Sadasivan; Sun, Ying

    2010-01-01

    An asynchronous hybrid brain-computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEP) paradigms is introduced. A P300 base system is used for information transfer, and is augmented to include SSVEP for control state detection. The proposed system has...

  16. 基于FPGA的异步电动机变频调速系统%Variable frequency driver system of asynchronous motor based on FPGA

    Institute of Scientific and Technical Information of China (English)

    吴俊; 邱建琪; 史涔溦; 王莉

    2012-01-01

    Aiming at the slow speed and poor stability of control system designed by traditional micro control unit(MCU)or digital signal processor (DSP) in the way of software, a hardware designed scheme of space vector pulse width modulation (SVPWM) based on field programmable gate array (FPCA) was presented, which based on the background of full digital motor-controller. Combining complished EDA design methodology and Verilog HDL, it was verified and implemented on one-chip FPGA. The "top-down" theme was used to develop core by dividing system according to it's function in the design. It was realized that, at first, design and simulation on single module, secondly, on the whole system, at last verification using FPCA. The algorithm was proved feasible through the simulation and experiment. On the basis of the platform, V/F open loop speed regulation system experiment was completed. The results indicate that the system has excellent stablity characteristic,reasonable chip utility,good reusability,superiority that the MCU and DSP do not have in real time,flexibility etc., and lays the foundation for the design of a special motor-controlling chip.%针对传统的单片机(MCU)或数字信号处理器(DSP)以软件方式实现的控制系统普遍存在速度慢、稳定性差等问题,以实现全数字电机控制器的集成化为背景,提出了一种基于现场可编程门阵列( FPGA)的空间电压矢量脉宽调制(SVPWM)硬件设计方案,并结合EDA模块化的设计方法和Verilog HDL硬件描述语言,在一片FPGA芯片中得到了验证和实现;采用“top-down”设计思想,对系统按功能划分模块进行了设计;首先对各功能模块进行了设计、仿真、验证,然后将整个系统组合起来进行了仿真、验证,最后利用FPGA进行了硬件验证;在此基础上,完成了异步电机SVPWM调制方式的V/F开环变频调速系统的实验.研究结果表明,该系统稳定性高、占用资源少、复用性高,在实

  17. Procedimiento para el cálculo de los parámetros de un modelo térmico simplificado del motor asincrónico Parameter estimation procedure for an asynchronous motor simplified thermal model

    OpenAIRE

    GÓMEZ SARDUY, JULIO R.; Percy R Viego Felipe; DE ARMAS TEYRA, MARCOS A.; Michel García Abreu

    2011-01-01

    En este trabajo se presenta un método para estimar las conductancias y capacitancias de un modelo térmico simplificado del motor asincrónico, utilizando una técnica de baja invasividad. El procedimiento permite predecir el incremento de temperatura del estator del motor asincrónico, tanto para régimen dinámico como en condiciones de estabilidad térmica. Se basa en la estimación paramétrica mediante un modelo de referencia, utilizando como optimizador un algoritmo genético (AG). Se logra en de...

  18. Reduction of power consumption in motor-driven applications by using PM motors; PM = Permanent Magnet; Reduktion af elforbrug til motordrift ved anvendelse af PM motorer

    Energy Technology Data Exchange (ETDEWEB)

    Hvenegaard, C.M.; Hansen, Mads P.R.; Groenborg Nikolaisen, C. (Teknologisk Institut, Taastrup (Denmark)); Nielsen, Sandie B. (Teknologisk Institut, AArhus (Denmark)); Ritchie, E.; Leban, K. (Aalborg Univ., Aalborg (Denmark))

    2009-12-15

    The traditional asynchronous motor with aluminum rotor is today by far the most widespread and sold electric motor, but a new and more energy efficient type of engine - the permanent magnet motor (PM motor) - is expected in the coming years to win larger and larger market shares. Several engine manufacturers in Europe, USA and Asia are now beginning to market the PM motors, which can replace the traditional asynchronous motor. The project aims to uncover the pros and cons of replacing asynchronous motors including EFF1 engines with PM motors, including the price difference. Furthermore, it is identified how the efficiency of PM motors is affected by low load levels and at various forms of control. Finally, the energy savings potential is analysed, by replacing asynchronous motors with PM motors. The study includes laboratory tests of PM motors, made in a test stand at Danish Technological Institute. (ln)

  19. Permanent magnet motors from ABB eliminate gearboxes%ABB永磁电机在船舶上的应用

    Institute of Scientific and Technical Information of China (English)

    钱丽春

    2004-01-01

    Permanent magnet motor is synchronous and eliminates brushes, rotor windings ABB's permanent magnet motor is an AC synchronous motor. With such a motor, there is no rotor slip, which provides better accuracy than induct asynchronous, motors.

  20. Text Mining: (Asynchronous Sequences

    Directory of Open Access Journals (Sweden)

    Sheema Khan

    2014-12-01

    Full Text Available In this paper we tried to correlate text sequences those provides common topics for semantic clues. We propose a two step method for asynchronous text mining. Step one check for the common topics in the sequences and isolates these with their timestamps. Step two takes the topic and tries to give the timestamp of the text document. After multiple repetitions of step two, we could give optimum result.

  1. Asynchronous Multiparty Computation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Geisler, Martin; Krøigaard, Mikkel;

    2009-01-01

    We propose an asynchronous protocol for general multiparty computation. The protocol has perfect security and communication complexity  where n is the number of parties, |C| is the size of the arithmetic circuit being computed, and k is the size of elements in the underlying field. The protocol...... multithreading. Benchmarking of a VIFF implementation of our protocol confirms that it is applicable to practical non-trivial secure computations....

  2. Asynchronous Variational Integrators

    OpenAIRE

    Lew, A.; Marsden, J. E.; Ortiz, M.; West, M

    2003-01-01

    We describe a new class of asynchronous variational integrators (AVI) for nonlinear elastodynamics. The AVIs are distinguished by the following attributes: (i) The algorithms permit the selection of independent time steps in each element, and the local time steps need not bear an integral relation to each other; (ii) the algorithms derive from a spacetime form of a discrete version of Hamilton’s variational principle. As a consequence of this variational structure, the algorith...

  3. Asynchronous Bounded Expected Delay Networks

    OpenAIRE

    Bakhshi, Rena; Endrullis, Jörg; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In ...

  4. Asynchronous machines. Direct torque control; Machines asynchrones. Commande par controle direct de couple

    Energy Technology Data Exchange (ETDEWEB)

    Fornel, B. de [Institut National Polytechnique, 31 - Toulouse (France)

    2006-05-15

    The asynchronous machine, with its low cost and robustness, is today the most widely used motor to make speed variators. However, its main drawback is that the same current generates both the magnetic flux and the torque, and thus any torque variation creates a flux variation. Such a coupling gives to the asynchronous machine a nonlinear behaviour which makes its control much more complex. The direct self control (DSC) method has been developed to improve the low efficiency of the scalar control method and for the specific railway drive application. The direct torque control (DTC) method is derived from the DSC method but corresponds to other type of applications. The DSC and DTC algorithms for asynchronous motors are presented in this article: 1 - direct control of the stator flux (DSC): principle, flux control, torque control, switching frequency of the inverter, speed estimation; 2 - direct torque control (DTC): principle, electromagnetic torque derivative, signals shape and switching frequency, some results, DTC speed variator without speed sensor, DTC application to multi-machine multi-converter systems; 3 - conclusion. (J.S.)

  5. DESIGN METHODOLOGY OF SELF-EXCITED ASYNCHRONOUS GENERATOR

    Directory of Open Access Journals (Sweden)

    Berzan V.

    2012-04-01

    Full Text Available The paper sets out the methodology of designing an asynchronous generator with capacitive self-excitation. It is known that its design is possible on the basis of serial synchronous motor with squirrel cage rotor. With this approach, the design reworked only the stator winding of electrical machines, making it cost-effectively implement the creation of the generator. Therefore, the methodology for the design, optimization calculations, the development scheme and the stator winding excitation system gain, not only of practical interest, and may also be useful for specialists in the field of electrical machines in the design of asynchronous generators.

  6. Asynchronous Power Flow Controller

    Directory of Open Access Journals (Sweden)

    Rahul Juneja

    2014-04-01

    Full Text Available In the present system demand of electrical power increases so fast and transfer of electrical power is need of today‟s scenario. . The electrical power is transfer at same frequency through AC transmission line. However, power generation may be at different frequencies such as wind generation, sources at islanding or power generation in different countries. The proposed Asynchronous Power Flow Controller (APFC system essentially consists of two back-to-back voltage source converters as “Shunt Converter” and “Series Converter” which is coupled via a common dc link provided by a dc storage capacitor This paper suggests the power transfer and control between the sources operating at different or same frequencies.

  7. Pro asynchronous programming with .NET

    CERN Document Server

    Blewett, Richard; Ltd, Rock Solid Knowledge

    2014-01-01

    Pro Asynchronous Programming with .NET teaches the essential skill of asynchronous programming in .NET. It answers critical questions in .NET application development, such as: how do I keep my program responding at all times to keep my users happy how do I make the most of the available hardware how can I improve performanceIn the modern world, users expect more and more from their applications and devices, and multi-core hardware has the potential to provide it. But it takes carefully crafted code to turn that potential into responsive, scalable applications.With Pro Asynchronous Programming

  8. Reducing energy with asynchronous circuits

    OpenAIRE

    Rivas Barragan, Daniel

    2012-01-01

    Reducing energy consumption using asynchronous circuits. The elastic clocks approach has been implemented along with a closed-feedback loop in order to achieve a lower energy consumption along with more reliability in integrated circuits.

  9. Simulation of the Double-closed Loop Three-phase Asynchronous Variable Voltage Control System

    OpenAIRE

    Shuhua Jiang

    2011-01-01

    When controlling the voltage and speed of the asynchronous motor, to expand the speed control range and reduce the speed fluctuation, the speed control system adopts two feedback control loops, i.e. the speed feedback control loop and the current feedback control loop. The principle and components of the double-closed loop three-phase asynchronous variable voltage control system are studied, and the simulation model and the test result based on MATLAB/Simulink are provided in this article thr...

  10. THE METHODS AND THE RESULTS OF THE TESTING OF AN ASYNCHRONOUS GENERATOR WITH SIX PHASE ZONES

    Directory of Open Access Journals (Sweden)

    Bogatyrev N. I.

    2016-03-01

    Full Text Available The article contain the peculiarities of testing asynchronous generator with sixzone winding on the basis of the asynchronous motor series 4A100S4 and analysis of obtained characteristics. Circuit parameters of the stator winding can significantly affect the characteristics of the asynchronous generator. Asynchronous generator was tested with a stator winding connected star, autotransformer and sectional winding. Use chastising windings opens the possibility of applying various circuits of capacitors and the load to asynchronous generators, which in turn affect the efficiency and stabilizing properties of the electric machine. Asynchronous generators to test with sectional winding by confirmation of theoretical calculations for determine the most optimal scheme under connect capacitors and load, testing the stator winding. The volume of testing for asynchronous generators standard is not defined, so we proposed testing method, taking into account the design features of the stator winding. Asynchronous generators were tested with the help of special equipment with the use of analyzer of energy power quality. Article contains characteristics of idling, short circuit and others, considered the heat mode. On the basis of the results we have determined the parameters of the circuit, the efficiency and power factor of induction generator

  11. Asynchronous Distributed Searchlight Scheduling

    CERN Document Server

    Obermeyer, Karl J; Bullo, Francesco

    2011-01-01

    This paper develops and compares two simple asynchronous distributed searchlight scheduling algorithms for multiple robotic agents in nonconvex polygonal environments. A searchlight is a ray emitted by an agent which cannot penetrate the boundary of the environment. A point is detected by a searchlight if and only if the point is on the ray at some instant. Targets are points which can move continuously with unbounded speed. The objective of the proposed algorithms is for the agents to coordinate the slewing (rotation about a point) of their searchlights in a distributed manner, i.e., using only local sensing and limited communication, such that any target will necessarily be detected in finite time. The first algorithm we develop, called the DOWSS (Distributed One Way Sweep Strategy), is a distributed version of a known algorithm described originally in 1990 by Sugihara et al \\cite{KS-IS-MY:90}, but it can be very slow in clearing the entire environment because only one searchlight may slew at a time. In an ...

  12. Asynchronous interactive control systems

    Science.gov (United States)

    Vuskovic, M. I.; Heer, E.

    1980-01-01

    A class of interactive control systems is derived by generalizing interactive manipulator control systems. The general structural properties of such systems are discussed and an appropriate general software implementation is proposed. This is based on the fact that tasks of interactive control systems can be represented as a network of a finite set of actions which have specific operational characteristics and specific resource requirements, and which are of limited duration. This has enabled the decomposition of the overall control algorithm into a set of subalgorithms, called subcontrollers, which can operate simultaneously and asynchronously. Coordinate transformations of sensor feedback data and actuator set-points have enabled the further simplification of the subcontrollers and have reduced their conflicting resource requirements. The modules of the decomposed control system are implemented as parallel processes with disjoint memory space communicating only by I/O. The synchronization mechanisms for dynamic resource allocation among subcontrollers and other synchronization mechanisms are also discussed in this paper. Such a software organization is suitable for the general form of multiprocessing using computer networks with distributed storage.

  13. Induction motor control design

    CERN Document Server

    Marino, Riccardo; Verrelli, Cristiano M

    2010-01-01

    ""Nonlinear and Adaptive Control Design for Induction Motors"" is a unified exposition of the most important steps and concerns in the design of estimation and control algorithms for induction motors. A single notation and modern nonlinear control terminology is used to make the book accessible to readers who are not experts in electric motors at the same time as giving a more theoretical control viewpoint to those who are. In order to increase readability, the book concentrates on the induction motor, eschewing the much more complex and less-well-understood control of asynchronous motors. The

  14. ASYNCHRONOUS ELECTRONIC DISCUSSION GROUP:

    Directory of Open Access Journals (Sweden)

    Tina Lim Swee KIM

    2007-01-01

    Full Text Available This paper examines the practice of online discussion in a course specially tailored for in-service teachers who are pursuing their basic degree qualification at a teacher training institute. Analyses of postings to the asynchronous electronic discussion group were made according to the type of postings as proposed by Poole (2000. Four focus areas were looked into, that is, content, technical, procedural, or non-academic. Analyses were done for each quarter of the 12 weeks of interaction. At the end of the learners’ participation in the EDG and before their end-of-course examination, the participants were then given a paper-based questionnaire asking their perceptions on the use of EDG as part of their coursework on the whole. Six aspects of EDG were examined, these are;Ø technical aspects, Ø motivation to use the EDG, Ø quality of interaction, Ø tutor’s response, Ø perceived learning, and Ø attitude towards EDG. Analyses on postings for the EDG showed that the bulk of the postings were made in the last quarter of the online discussions. Further, 97.8% of the postings were on content and the types of content posting registered were predominantly questions (41.19% and those that sought clarification/elaboration (37.48%. Findings from this study suggest that overall the participants were satisfied with the six aspects of EDG examined. The aspect that recorded the highest mean was ‘motivation to read tutor’s responses’ whilst the lowest mean (and the only one with negative perception was for ‘worthiness of time spent on online discussions’.

  15. Energy efficiency with EC, asynchronous or PM motors; Energieeffizienz mit EC-, Asynchron- oder PM-Motor?

    Energy Technology Data Exchange (ETDEWEB)

    Burghardt, Michael [Danfoss GmbH, VLT Antriebstechnik, Offenbach/Main (Germany)

    2011-07-15

    Energy efficiency, reduced emissions of greenhouse gases, lower energy consumption - keywords, which actually result in too many controversial discussions in the press. There is an agreement in the target to reduce the energy consumption. However, there are many different approaches to achieve this goal. The contribution under consideration reports on similarities and differences of the used engine technologies.

  16. Distribution of magnetic field of linear induction motor

    OpenAIRE

    Sadauskas, T.; Smilgevičius, A.; Savickienė, Z.

    2007-01-01

    In this article is investigated the distribution of magnetic field of linear induction motor. The are two models for simulation: three-phase asynchronous linear motor and single-phase linear capacitor motor. Simulations results of asynchronous LIM at different instants of time and at different widths of air gap are presented. The are given results of simulation, which show the change of magnetic flux at different instants of time of linear capacitor motor how magnetic field varies at differen...

  17. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    domain by introducing a computation model, which resembles the synchronous datapath and control architecture, but which is completely asynchronous. The model contains the possibility for isolating some or all of the functional units by locking their respective inputs and outputs while the functional unit...

  18. Acquiring Knowledge from Asynchronous Discussion

    Science.gov (United States)

    Teo, Yiong Hwee; Webster, Len

    2008-01-01

    This article discusses a study which was designed to explore how online scaffolding can be incorporated to support knowledge acquisition in asynchronous discussion. A group of Singapore preservice teachers engaged in collaborative critiquing of videos before they embarked on their video projects to illustrate what constitutes good and bad video…

  19. Asynchronous sequential machine design and analysis

    CERN Document Server

    Tinder, Richard

    2009-01-01

    Asynchronous Sequential Machine Design and Analysis provides a lucid, in-depth treatment of asynchronous state machine design and analysis presented in two parts: Part I on the background fundamentals related to asynchronous sequential logic circuits generally, and Part II on self-timed systems, high-performance asynchronous programmable sequencers, and arbiters.Part I provides a detailed review of the background fundamentals for the design and analysis of asynchronous finite state machines (FSMs). Included are the basic models, use of fully documented state diagrams, and the design and charac

  20. Preliminary exploration of fault diagnosis for rotor bar breaking of squirrel cage asynchronous motors based on coil detection%基于线圈探测的笼型异步电机转子断条故障诊断初探

    Institute of Scientific and Technical Information of China (English)

    武玉才; 李永刚; 李和明; 许伯强

    2012-01-01

    笼型异步电机转子断条故障研究是目前国内外关注的热点之一,已经提出的诊断方法在进行故障特征提取时具有一定困难.分析了异步电机参数与导条电气特征间的关系,通过数值仿真得到断条前后转子电流分布规律,结合有限元工具Ansys分析了导条漏磁场在故障前后的变化.研究结果表明探测线圈输出的电压幅值与导条故障的严重程度之间存在对应关系,探测线圈法可以应用于笼型异步电动机转子断条故障的诊断.%Study on the fault diagnosis of rotor broken-bar of cage induction motor is one of the focus of attention worldwide. Diagnostic methods already proposed are difficult to extract the fault feature. The relationship among motor parameters and bar electrical features is analyzed in this paper, and the rotor current distributions before and after the bar breaking fault are obtained by numerical simulation. By combining with the finite element tool Ansys, the change of leakage magnetic field after fault is analyzed. The results show that the voltage amplitude sensed at the detection coil has close correlations with bar fault severity, and search coil method can be used to diagnose of asynchronous motor rotor bar breaking fault.

  1. Control algorithms for single inverter dual induction motor system applied to railway traction; Commande algorithmique d'un systeme mono-onduleur bimachine asynchrone destine a la traction ferroviaire

    Energy Technology Data Exchange (ETDEWEB)

    Pena Eguiluz, R.

    2002-11-15

    The goal of this work concerns the modelling and the behaviour characterisation of a single inverter dual induction motor system applied to a railway traction bogie (BB36000) in order to concept its control. First part of this job is dedicated to the detailed description of overall system. The influence analysis of the internal perturbations (motor parameters variation) and, external perturbations (pantograph detachment, adherence loss, stick-slip) of the system have made considering the field oriented control applied to each motor of the bogie (classical traction structure). vi In a second part, a novel propulsion structure is proposed. It is composed by a single pulse-width modulated two level voltage source inverter. It supplies two parallel connected induction motors, which generate the transmitted traction force to the bogie wheels. The locomotive case represents the common load for the two motors. Several co-operative control strategies (CS) are studied. They are: the mean CS, the double mean CS, the master - slave switched CS and, the mean differential CS. In addition, an appropriated electric modes observer structure for these different controls has studied. These controls have validated applying the perturbations to the models using the solver SABER. This special approach is equivalent to quasi-experimentation, because the mechanical and the electrical system components have modelled using MAST language and, the sample control has created by a C code programme in the SABER environment. Third part is dedicated to the mechanical sensor suppression and, its adaptation in the cooperative control strategies. The partial speed reconstruction methods are: the fundamental frequency relation, the mechanical Kalman filter, the variable structure observer and the MRAS. Finally, the hardware system configuration of the experimental realisation is described. (author)

  2. Asynchronous control for networked systems

    CERN Document Server

    Rubio, Francisco; Bencomo, Sebastián

    2015-01-01

    This book sheds light on networked control systems; it describes different techniques for asynchronous control, moving away from the periodic actions of classical control, replacing them with state-based decisions and reducing the frequency with which communication between subsystems is required. The text focuses specially on event-based control. Split into two parts, Asynchronous Control for Networked Systems begins by addressing the problems of single-loop networked control systems, laying out various solutions which include two alternative model-based control schemes (anticipatory and predictive) and the use of H2/H∞ robust control to deal with network delays and packet losses. Results on self-triggering and send-on-delta sampling are presented to reduce the need for feedback in the loop. In Part II, the authors present solutions for distributed estimation and control. They deal first with reliable networks and then extend their results to scenarios in which delays and packet losses may occur. The novel ...

  3. Asynchronous Anytime Sequential Monte Carlo

    OpenAIRE

    Paige, Brooks; Wood, Frank; Doucet, Arnaud; Teh, Yee Whye

    2014-01-01

    We introduce a new sequential Monte Carlo algorithm we call the particle cascade. The particle cascade is an asynchronous, anytime alternative to traditional particle filtering algorithms. It uses no barrier synchronizations which leads to improved particle throughput and memory efficiency. It is an anytime algorithm in the sense that it can be run forever to emit an unbounded number of particles while keeping within a fixed memory budget. We prove that the particle cascade is an unbiased mar...

  4. Asynchronous MPI for the Masses

    OpenAIRE

    Wittmann, Markus; Hager, Georg; Zeiser, Thomas; Wellein, Gerhard

    2013-01-01

    We present a simple library which equips MPI implementations with truly asynchronous non-blocking point-to-point operations, and which is independent of the underlying communication infrastructure. It utilizes the MPI profiling interface (PMPI) and the MPI_THREAD_MULTIPLE thread compatibility level, and works with current versions of Intel MPI, Open MPI, MPICH2, MVAPICH2, Cray MPI, and IBM MPI. We show performance comparisons on a commodity InfiniBand cluster and two tier-1 systems in Germany...

  5. GAMIFICATION IN ASYNCHRONOUS EDUCATION PROCESS

    Directory of Open Access Journals (Sweden)

    B. P. Dyakonov

    2016-03-01

    Full Text Available The author of the paper discourses on the prospects of education in the context of the global tendency towards informatization and virtualization of the modern world, influence of these processes on personalized senses of education and educational values and related problems of methodological and technological education in relation to the personalized meanings and educational values. Educational individualization is defined by the author as the most expected way of educational evolution. Distance learning is studied as the main example of the modern transformative educational model. Asynchronous education is explored and characterized as one of the distance learning examples. While defining what asynchronous distance learning is, the author explores its role in the specifics of forming a subject to subject educational approach, while forecasting difficulties in creating holistic asynchronous educational environment. Gamification techniques in the educational process are studied with their respective opportunities and threats, examples in grad and post grad professional studies are provided, including but not limited to foreign language studies. Addictiveness as the goal and means of a build in gamification process is explored as the way to bridge the gap between students and the educators. The author studies gamification in the context of minimizing negative connotations from the educational process, while controversies between pain and game approaches of getting knowledge are brought into light.

  6. Dynamic D-Q Axis Modeling Of Three-Phase Asynchronous Machine Using Matlab

    OpenAIRE

    SHAKUNTLA BOORA, S.K AGARWAL, K.S SANDHU

    2013-01-01

    Abstract:This paper presents a dynamic d-q axis model of three- phase asynchronous motor in synchronously rotating frame. The systems of differential equations representing the dynamic state behaviours of the machine as developed are implemented in MATLAB/SIMULINK. The effects of the stepped sequence of mechanical loading on the motor output variables namely: three-phase stator currents (ia, ib and ic), electromechanical torque and rotor speed, d-q stator and rotor currents (iqs, ids, iqr and...

  7. Hitting Families of Schedules for Asynchronous Programs

    OpenAIRE

    Chistikov, Dmitry; Majumdar, Rupak; Niksic, Filip

    2016-01-01

    Asynchronous programming is a ubiquitous idiom for concurrent programming, where sequential units of code, called events, are scheduled and run atomically by a scheduler. While running, an event can post additional events for future execution by the scheduler. Asynchronous programs can have subtle bugs due to the non-deterministic scheduling of events, and a lot of recent research has focused on systematic testing of these programs. Empirically, many bugs in asynchronous programs have small b...

  8. A method for designing asynchronous probabilistic processes

    OpenAIRE

    Abbes, Samy

    2013-01-01

    We present a method for constructing asynchronous probabilistic processes. The asynchronous probabilistic processes thus obtained are called invariant. They generalize the familiar independent and identically distributed sequences of random variables to an asynchronous framework. Invariant processes are shown to be characterised by a finite family of real numbers, their characteristic numbers. Our method provides first a way to obtaining necessary and sufficient normalization conditions for a...

  9. Asynchronous Methods for Deep Reinforcement Learning

    OpenAIRE

    Mnih, Volodymyr; Badia, Adrià Puigdomènech; Mirza, Mehdi; Graves, Alex; Lillicrap, Timothy P.; Harley, Tim; Silver, David; Kavukcuoglu, Koray

    2016-01-01

    We propose a conceptually simple and lightweight framework for deep reinforcement learning that uses asynchronous gradient descent for optimization of deep neural network controllers. We present asynchronous variants of four standard reinforcement learning algorithms and show that parallel actor-learners have a stabilizing effect on training allowing all four methods to successfully train neural network controllers. The best performing method, an asynchronous variant of actor-critic, surpasse...

  10. Asynchronous Discussions and Assessment in Online Learning

    Science.gov (United States)

    Vonderwell, Selma; Liang, Xin; Alderman, Kay

    2007-01-01

    This case study explored asynchronous online discussions, assessment processes, and the meaning students derived from their experiences in five online graduate courses at the Colleges of Education of two Midwestern higher education institutions. The findings suggest that asynchronous online discussions facilitate a multidimensional process of…

  11. Asynchronous Parallelization of a CFD Solver

    Directory of Open Access Journals (Sweden)

    Daniel S. Abdi

    2015-01-01

    Full Text Available A Navier-Stokes equations solver is parallelized to run on a cluster of computers using the domain decomposition method. Two approaches of communication and computation are investigated, namely, synchronous and asynchronous methods. Asynchronous communication between subdomains is not commonly used in CFD codes; however, it has a potential to alleviate scaling bottlenecks incurred due to processors having to wait for each other at designated synchronization points. A common way to avoid this idle time is to overlap asynchronous communication with computation. For this to work, however, there must be something useful and independent a processor can do while waiting for messages to arrive. We investigate an alternative approach of computation, namely, conducting asynchronous iterations to improve local subdomain solution while communication is in progress. An in-house CFD code is parallelized using message passing interface (MPI, and scalability tests are conducted that suggest asynchronous iterations are a viable way of parallelizing CFD code.

  12. Simulation of Indirect Vector Control System of the Asynchronous Motor%异步电动机间接矢量控制系统的仿真研究

    Institute of Scientific and Technical Information of China (English)

    石瑶; 李宏胜

    2015-01-01

    The indirect vector control system of the AC motor with rotor flux open-loop has been widely used because of the simple structure and high control performance. The indirect oriented vector control system was established based on Matlab/simulink. Then it was a research if the changes of the rotor time constant had effect on the rotor flux oriented. The results showed that the real-time adjustment of the rotor time constant had an important role in the system control performance.%异步电动机的转子磁链开环间接矢量控制系统因其结构简单,控制性能高得到广泛的应用。利用Matlab/simulink仿真软件建立了间接定向的矢量控制系统,并根据模型探讨转子时间常数的变化对转子磁链定向的影响。结果表明,转子时间常数的实时调整对系统控制性能有重要作用。

  13. Abstracting Asynchronous Multi-Valued Networks

    Directory of Open Access Journals (Sweden)

    J. Steggles

    2011-01-01

    Full Text Available Multi-valued networks (MVNs provide a simple yet expressive qualitative state based modelling approach for biological systems. In this paper we develop an abstraction theory for asynchronous MVNs that allows the state space of a model to be reduced while preserving key properties. The abstraction theory therefore provides a mechanism for coping with the state space explosion problem and supports the analysis and comparison of MVNs. We take as our starting point the abstraction theory for synchronous MVNs which uses the under- approximation approach of trace set inclusion. We show this definition of asynchronous abstraction allows the sound inference of analysis properties and preserves other interesting model properties. One problem that arises in the asynchronous case is that the trace set of an MVN can be infinite making a simple trace set inclusion check infeasible. To address this we develop a decision procedure for checking asynchronous abstractions based on using the finite state graph of an asynchronous MVN to reason about its trace semantics and formally show that this decision procedure is correct. We illustrate the abstraction techniques developed by considering two detailed case studies in which asynchronous abstractions are identified and validated for existing asynchronous MVN models taken from the literature.

  14. Simulation Study of Asynchronous Motor in Slip Frequency Control Base on Three-level%基于三电平异步电机转差频率矢量控制的仿真研究

    Institute of Scientific and Technical Information of China (English)

    付光杰; 王圣慧; 陈舒; 王建任; 顾宝龙

    2012-01-01

    The direct rotor magnetic field oriented vector control system of Aysnchronous motor is very complex,and the flux feedback signal is not easy to obtain. So this article presents a three-level slip frequency control method with high control precision, control method is simple, high static and dynamic performance characteristics based on slip frequency control method, This method does not need complex coordinate transformation and flux detection. By application of MATLAB/Simulink software to build a simulation model, in the simulation a large number of parameters through the process of debugging and optimization of the ratio adjustment, this system can eliminate the steady-state error and the ability to quickly reduce the deviation. The simulation results show, the three-level inverter slip frequency control system has good control performance.%异步电动机的直接转子磁场定向矢量控制系统极其复杂,而且磁链反馈信号不易获取,鉴于此提出了一种 基于三电平转差频率控制的方法,该方法无需进行复杂的坐标变换和磁通检测,具有控制精度高、控制方法简单、较高的动静态性能等特点.应用MATLAB/Simulink软件搭建了系统的仿真模型,在仿真实验过程中通过大量的参数调试和配比的优化调节,本系统能够消除稳态误差并能够快速减小偏差.仿真结果证明了,三电平转差频率变频调速系统具有良好的控制性能.

  15. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

  16. Carrying Synchronous Voice Data On Asynchronous Networks

    Science.gov (United States)

    Bergman, Larry A.

    1990-01-01

    Buffers restore synchronism for internal use and permit asynchronism in external transmission. Proposed asynchronous local-area digital communication network (LAN) carries synchronous voice, data, or video signals, or non-real-time asynchronous data signals. Network uses double buffering scheme that reestablishes phase and frequency references at each node in network. Concept demonstrated in token-ring network operating at 80 Mb/s, pending development of equipment operating at planned data rate of 200 Mb/s. Technique generic and used with any LAN as long as protocol offers deterministic (or bonded) access delays and sufficient capacity.

  17. Implementing LOTOS as asynchronously Communicating Processes

    OpenAIRE

    Sjödin, Peter

    1990-01-01

    A technique is presented for translating LOTOS specifications into implementations executing as asynchronously communicating processes. This generation of implementations is described as transformations of LOTOS expressions. A protocol for implementing LOTOS synchronisation is described.

  18. Asynchronous Data Fusion With Parallel Filtering Frame

    OpenAIRE

    Na Li; Junhui Liu

    2011-01-01

    This paper studies the design of data fusion algorithm for asynchronous system with integer times sampling. Firstly, the multisensor asynchronous samplings is mapped to the basic axis, accordingly a sampling sequence of single sensor can be taken. Secondly, aiming at the sensor with the densest sampling points, the modified parallel filtering is given. Afterwards, the sequential filtering fusion method is introduced to deal with the case that there are multiple mapped measurements at some sam...

  19. Asynchronous communication in real space process algebra

    OpenAIRE

    Baeten, JCM Jos; Bergstra, JA Jan

    1992-01-01

    A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a priority mechanism allows to express the broadcasting mechanism. As an application, a protocol is specified in which the receiver moves with respect to the sender.

  20. Performance Analysis of Asynchronous Multicarrier Wireless Networks

    OpenAIRE

    Lin, Xingqin; Jiang, Libin; Andrews, Jeffrey G.

    2014-01-01

    This paper develops a novel analytical framework for asynchronous wireless networks deploying multicarrier transmission. Nodes in the network have different notions of timing, so from the viewpoint of a typical receiver, the received signals from different transmitters are asynchronous, leading to a loss of orthogonality between subcarriers. We first develop a detailed link-level analysis based on OFDM, based on which we propose a tractable system-level signal-to-interference-plus-noise ratio...

  1. Performance Analysis of Induction Motor of Electric Vehicle Using Vector control

    Institute of Scientific and Technical Information of China (English)

    Liu ping

    2012-01-01

    According to the principle of Vector controlused in an asyn- chronous motor,a simulation model of the asynchronous motor in elec-tric vehicle and Vectorcontrolsystem was established with Matlab/Simu-link software. Simulation analysis of the asynchronous motor driving an electric vehicle was performedunder the classic mode of EV , and the simulation results show the modeland control scheme has better stable and dynamic performance,whichcanbe a good candidate for electric ve- hicle propulsion system

  2. The bond-graph design of a motor used for electrical traction

    Directory of Open Access Journals (Sweden)

    Adriana Grava

    2009-10-01

    Full Text Available In this paper the asynchronous motorwith cage, used for electrical traction is studied andanalyzed. For this motor we realized the associatedbond-graph, we pointed out the equations thatdescribe this motor, and we analyzed the electricaland mechanical features of this motor, by using thesimulation program 20 SIM, in order to improve theperformances of this motor even from the early stageof design.

  3. Asynchronous Complex Pipeline Design Based on ARM Instruction Set

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; WANG Qin; PENG Rui-hua; FU Yu-zhuo

    2008-01-01

    This paper proposes an asynchronous complex pipeline based on ARM-V3 instruction set. Muller pipeline structure is used as prototype, and the factors which may affect pipeline performance are analyzed. To balance the difficulty of asynchronous design and performance analysis, both complete asynchronous and partial asynchronous structures aere designed and compared. Results of comparison with the well-Rnown industrial product ARM922T verify that about 30% and 40% performance improvement of the partial and complete asynchronous complex pipelines can be obtained respectively. The design methodologies can also be used in the design of other asynchronous pipelines.

  4. Soft Switched Space Vector PWM Control Of Asynchronous Motor

    OpenAIRE

    Burak Akin; M. Hadi Sarul

    2016-01-01

    In this study, the parallel-resonance DC link inverter (PRDCLI) topology is chosen and detailed simulation analysis of that circuit is given. It is observed that all the semiconductors in the circuit turn on and turn off under approximately zero voltage switching (ZVS) or zero current switching (ZCS) and no additional voltage stress occurred on the main switch. The proposed soft switched inverter system has % 95.3 total efficiency with space vector PWM control.

  5. Asynchronous decentralized method for interconnected electricity markets

    International Nuclear Information System (INIS)

    This paper presents an asynchronous decentralized method to solve the optimization problem of interconnected electricity markets. The proposed method decomposes the optimization problem of combined electricity markets into individual optimization problems. The impact of neighboring markets' information is included in the objective function of the individual market optimization problem by the standard Lagrangian relaxation method. Most decentralized optimization methods use synchronous models of communication to exchange updated market information among markets during the iterative process. In this paper, however, the solutions of the individual optimization problems are coordinated through an asynchronous communication model until they converge to the global optimal solution of combined markets. Numerical examples are presented to demonstrate the advantages of the proposed asynchronous method over the existing synchronous methods. (author)

  6. Electric motors and drives. Pt. 27. AC motors. Pt. 1; Elektrische Maschinen und Antriebe. T. 27. Drehfeldmaschinen. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Baral, Andreas [FHWT - Private Fachhochschule fuer Wirtschaft und Technik, Oldenburg (Germany). Elektrische Maschinen und Antriebstechnik

    2009-11-15

    AC motors like, for example, asynchronous and synchronous motors have an important role in propulsion technology. They are based on the principle of a rotary magnetic field resulting from the motor geometry and from a multiphase (usually three-phase) voltage system. The rotational frequency of the field and thus the rotary speed of the motors are directly dependent on the frequency of the feeding voltage system. (orig.)

  7. Acceptability of an Asynchronous Learning Forum on Mobile Devices

    Science.gov (United States)

    Chang, Chih-Kai

    2010-01-01

    Mobile learning has recently become noteworthy because mobile devices have become popular. To construct an asynchronous learning forum on mobile devices is important because an asynchronous learning forum is always an essential part of networked asynchronous distance learning. However, the input interface in handheld learning devices, which is…

  8. The non-anticipation of the asynchronous systems

    OpenAIRE

    Vlad, Serban E.

    2008-01-01

    The asynchronous systems are the models of the asynchronous circuits from the digital electrical engineering and non-anticipation is one of the most important properties in systems theory. Our present purpose is to introduce several concepts of non-anticipation of the asynchronous systems.

  9. Asynchronous Rumor Spreading on Random Graphs

    CERN Document Server

    Panagiotou, Konstantinos

    2016-01-01

    We perform a thorough study of various characteristics of the asynchronous push-pull protocol for spreading a rumor on Erd\\H{o}s-R\\'enyi random graphs $G_{n,p}$, for any $p>c\\ln(n)/n$ with $c>1$. In particular, we provide a simple strategy for analyzing the asynchronous push-pull protocol on arbitrary graph topologies and apply this strategy to $G_{n,p}$. We prove tight bounds of logarithmic order for the total time that is needed until the information has spread to all nodes. Surprisingly, the time required by the asynchronous push-pull protocol is asymptotically almost unaffected by the average degree of the graph. Similarly tight bounds for Erd\\H{o}s-R\\'enyi random graphs have previously only been obtained for the synchronous push protocol, where it has been observed that the total running time increases significantly for sparse random graphs. Finally, we quantify the robustness of the protocol with respect to transmission and node failures. Our analysis suggests that the asynchronous protocols are particu...

  10. Increasing Student Engagement Using Asynchronous Learning

    Science.gov (United States)

    Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

    2015-01-01

    Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

  11. Duration of asynchronous operations in distributed systems

    OpenAIRE

    Makhaniok, Mikhail; Männer, Reinhard

    1995-01-01

    A distributed asynchronous system is investigated. Its processing elements execute common operations concurrently and distributively. They are implemented as combinatorial circuits and exchange data via open collector bus lines. A method is presented to identify and to minimize the duration of an operation and therefore to increase the performance of the system. No hardware modifications are required.

  12. CCS, locations and asynchronous transition systems

    DEFF Research Database (Denmark)

    Mukund, Madhavan; Nielsen, Mogens

    system for CCS by introducing labels on the transitions with information about the locations of events. We then show that the resulting transition system is an asynchronous transition system which has the additional property of being elementary, which means that it can also be represented by a 1-safe net...

  13. Disc Motor: Conventional and Superconductor Simulated Results Analysis

    Science.gov (United States)

    Inácio, David; Martins, João; Neves, Mário Ventim; Álvarez, Alfredo; Rodrigues, Amadeu Leão

    Taking into consideration the development and integration of electrical machines with lower dimensions and higher performance, this paper presents the design and development of a three-phase axial flux disc motor, with 50 Hz frequency supply. It is made with two conventional semi-stators and a rotor, which can be implemented with a conventional aluminum disc or a high temperature-superconducting disc. The analysis of the motor characteristics is done with a 2D commercial finite elements package, being the modeling performed as a linear motor. The obtained results allow concluding that the superconductor motor provides a higher force than the conventional one. The conventional disc motor presents an asynchronous behavior, like a conventional induction motor, while the superconductor motor presents both synchronous and asynchronous behaviors.

  14. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

    Madsen, Kaj; Caprani, O.; Stauning, Ole

    1997-01-01

    In the search for regions that contain fixed points ofa real function of several variables, tests based on interval calculationscan be used to establish existence ornon-existence of fixed points in regions that are examined in the course ofthe search. The search can e.g. be performed as a...... synchronous (sequential) interval iteration:In each iteration step all components of the iterate are calculatedbased on the previous iterate. In this case it is straight forward to base simple interval existence and non-existencetests on the calculations done in each step of the iteration. The search can also...... be performed as an asynchronous (parallel) iteration: Only a few components are changed in each stepand this calculation is in general based on components from differentprevious iterates. For the asynchronous iteration it turns out thatsimple tests of existence and non-existence can be based on...

  15. Computing by Temporal Order: Asynchronous Cellular Automata

    Directory of Open Access Journals (Sweden)

    Michael Vielhaber

    2012-08-01

    Full Text Available Our concern is the behaviour of the elementary cellular automata with state set 0,1 over the cell set Z/nZ (one-dimensional finite wrap-around case, under all possible update rules (asynchronicity. Over the torus Z/nZ (n<= 11,we will see that the ECA with Wolfram rule 57 maps any v in F_2^n to any w in F_2^n, varying the update rule. We furthermore show that all even (element of the alternating group bijective functions on the set F_2^n = 0,...,2^n-1, can be computed by ECA57, by iterating it a sufficient number of times with varying update rules, at least for n <= 10. We characterize the non-bijective functions computable by asynchronous rules.

  16. Inhibition Controls Asynchronous States of Neuronal Networks

    Science.gov (United States)

    Treviño, Mario

    2016-01-01

    Computations in cortical circuits require action potentials from excitatory and inhibitory neurons. In this mini-review, I first provide a quick overview of findings that indicate that GABAergic neurons play a fundamental role in coordinating spikes and generating synchronized network activity. Next, I argue that these observations helped popularize the notion that network oscillations require a high degree of spike correlations among interneurons which, in turn, produce synchronous inhibition of the local microcircuit. The aim of this text is to discuss some recent experimental and computational findings that support a complementary view: one in which interneurons participate actively in producing asynchronous states in cortical networks. This requires a proper mixture of shared excitation and inhibition leading to asynchronous activity between neighboring cells. Such contribution from interneurons would be extremely important because it would tend to reduce the spike correlation between neighboring pyramidal cells, a drop in redundancy that could enhance the information-processing capacity of neural networks. PMID:27274721

  17. Asynchronous Nano-Electronics: Preliminary Investigation

    OpenAIRE

    Martin, Alain J.; Prakash, Piyush

    2008-01-01

    This paper is a preliminary investigation in implementing asynchronous QDI logic in molecular nano-electronics, taking into account the restricted geometry, the lack of control on transistor strengths, the high timing variations. We show that the main building blocks of QDI logic can be successfully implemented; we illustrate the approach with the layout of an adder stage. The proposed techniques to improve the reliability of QDI apply to nano-CMOS as well.

  18. Rapid, generalized adaptation to asynchronous audiovisual speech

    OpenAIRE

    Van der Burg, Erik; Goodbourn, Patrick T.

    2015-01-01

    The brain is adaptive. The speed of propagation through air, and of low-level sensory processing, differs markedly between auditory and visual stimuli; yet the brain can adapt to compensate for the resulting cross-modal delays. Studies investigating temporal recalibration to audiovisual speech have used prolonged adaptation procedures, suggesting that adaptation is sluggish. Here, we show that adaptation to asynchronous audiovisual speech occurs rapidly. Participants viewed a brief clip of an...

  19. Accurate estimator of correlations between asynchronous signals

    OpenAIRE

    Toth, Bence; Kertesz, Janos

    2008-01-01

    The estimation of the correlation between time series is often hampered by the asynchronicity of the signals. Cumulating data within a time window suppresses this source of noise but weakens the statistics. We present a method to estimate correlations without applying long time windows. We decompose the correlations of data cumulated over a long window using decay of lagged correlations as calculated from short window data. This increases the accuracy of the estimated correlation significantl...

  20. Quantitative phase microscopy with asynchronous digital holography

    OpenAIRE

    Chalut, Kevin J.; Brown, William J.; Wax, Adam

    2007-01-01

    We demonstrate a new method of measuring quantitative phase in imaging of biological materials. This method, asynchronous digital holography, employs knowledge of a moving fringe created by acousto-optic modulators to execute phase-shifting interferometry using two near-simultaneous interferograms. The method can be used to obtain quantitative phase images of dynamic biological samples on millisecond time scales. We present results on a standard sample, and on live cell samples.

  1. Blending Online Asynchronous and Synchronous Learning

    Directory of Open Access Journals (Sweden)

    Lisa C. Yamagata-Lynch

    2014-04-01

    Full Text Available In this article I will share a qualitative self-study about a 15-week blended 100% online graduate level course facilitated through synchronous meetings on Blackboard Collaborate and asynchronous discussions on Blackboard. I taught the course at the University of Tennessee (UT during the spring 2012 semester and the course topic was online learning environments. The primary research question of this study was: How can the designer/instructor optimize learning experiences for students who are studying about online learning environments in a blended online course relying on both synchronous and asynchronous technologies? I relied on student reflections of course activities during the beginning, middle, and the end of the semester as the primary data source to obtain their insights regarding course experiences. Through the experiences involved in designing and teaching the course and engaging in this study I found that there is room in the instructional technology research community to address strategies for facilitating online synchronous learning that complement asynchronous learning. Synchronous online whole class meetings and well-structured small group meetings can help students feel a stronger sense of connection to their peers and instructor and stay engaged with course activities. In order to provide meaningful learning spaces in synchronous learning environments, the instructor/designer needs to balance the tension between embracing the flexibility that the online space affords to users and designing deliberate structures that will help them take advantage of the flexible space.

  2. Enabling techniques for asynchronous coherent OCDMA

    Science.gov (United States)

    Wang, Xu; Wada, Naoya; Kitayama, Ken-ichi

    2005-11-01

    The coherent OCDMA system could suffer from severe multiple access interference (MAI) and beat noise, which limit the maximum number of active users that can be supported in a network. One effective method to reduce the beat noise as well as the MAI noise is to lower the interference level by adopting ultra-long optical code. Applying optical thresholding technique is also crucial to enable data-rate detection for achieving a practical OCDMA system. In this paper, we review the recent progress in the key enabling techniques for asynchronous coherent OCDMA: the novel encoder/decoders including spatial lightwave phase modulator, micro-ring resonator for spectral phase coding and superstructured FBG (SSFBG) and AWG type encode/decoder for time-spreading coding; optical thresholding techniques with PPLN and nonlinearity in fiber. The FEC has also been applied in OCDMA system recently. With 511-chip SSFBG and SC-based optical thresholder, 10-user, truly-asynchronous gigabit OCDMA transmission has been successfully achieved. Most recently, a record throughput 12×10.71 Gbps truly-asynchronous OCDMA has been demonstrated by using the 16×16 ports AWG-type encoder/decoder and FEC transmit ITU-T G.709 OTN frames.

  3. Prototype energy-saving motor; Prototyp Energiesparmotor

    Energy Technology Data Exchange (ETDEWEB)

    Weingartner, J. [Baechli AG, Kriens-Obernau (Switzerland); Lindegger, M. [Circle Motor AG, Guemligen (Switzerland)

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of investigations made on the development of an energy-efficient electric motor. The aim of the prototype 'Eco-Motor' project was the development of a winding technique and the optimisation of the design of the stator. Various winding techniques (toroid winding, core winding, coil winding) were examined and used in the realisation of prototype 'Eco-Motors' for a nominal voltage of 230 V a.c. The designs were evaluated in both a simulation (FEMM) and as well as in the test facilities at the College of Engineering and Architecture in Lucerne, Switzerland. The measured data of the 'Eco-Motor' were then compared with a standard asynchronous motor. The 'Eco-Motor' with a toroid winding had the best efficiency. At low loads, all 'Eco-Motor' prototypes have a higher efficiency than asynchronous motors. On the other hand, none of the 'Eco-Motors' have yet reached the nominal power of 250 W. The developers state, however, that with a few adjustments this should pose no problems.

  4. Asynchronous detection of kinesthetic attention during mobilization of lower limbs using EEG measurements

    Science.gov (United States)

    Melinscak, Filip; Montesano, Luis; Minguez, Javier

    2016-02-01

    Objective. Attention is known to modulate the plasticity of the motor cortex, and plasticity is crucial for recovery in motor rehabilitation. This study addresses the possibility of using an EEG-based brain-computer interface (BCI) to detect kinesthetic attention to movement. Approach. A novel experiment emulating physical rehabilitation was designed to study kinesthetic attention. The protocol involved continuous mobilization of lower limbs during which participants reported levels of attention to movement—from focused kinesthetic attention to mind wandering. For this protocol an asynchronous BCI detector of kinesthetic attention and deliberate mind wandering was designed. Main results. EEG analysis showed significant differences in theta, alpha, and beta bands, related to the attentional state. These changes were further pinpointed to bands relative to the frequency of the individual alpha peak. The accuracy of the designed BCI ranged between 60.8% and 68.4% (significantly above chance level), depending on the used analysis window length, i.e. acceptable detection delay. Significance. This study shows it is possible to use self-reporting to study attention-related changes in EEG during continuous mobilization. Such a protocol is used to develop an asynchronous BCI detector of kinesthetic attention, with potential applications to motor rehabilitation.

  5. SELF CONTROL OF SYNCHRONOUS MOTOR FED BY MATRIX CONVERTER

    OpenAIRE

    CALISKAN, ABUZER; Orhan, Ahmet

    2012-01-01

    In this study self control of synchronous motor fed by matrix converter was examined by developing a Matlab/simulink model. Self control of synchronous motor was performed by fixing frequency of stator voltage to rotor speed. Thus, the probable danger of asynchronism of the motor during transient operation in open loop control is removed. In the developed model, simplified Venturini modulation algorithm was used. This algorithm provides unity fundamental displacement factor at the input regar...

  6. Doubly-fed asynchronous machine with 3-level VSI for variable speed pump storage

    Energy Technology Data Exchange (ETDEWEB)

    Sapin, A.; Hodder, A.; Simond, J.J. [Swiss Federal Institute of Technology, Electromechanics and Electrical Machines Laboratory, Lausanne (Switzerland); Schafer, D. [Alstom Power Generation Ltd, Birr (Switzerland)

    2000-08-01

    This paper deals with a fixed-frequency variable-speed motor/generator with 3-level VSI (Voltage Source Inverter) cascade. The 3-level VSI is applied to a DASM (Doubly-fed ASynchronous Machine) for large pump storage plants. The extension to 3 levels is the original part of this paper. The whole system behavior has been simulated using the 'SIMSEN' simulation software. This paper focuses on the simulation results and also on the comparison with the 12-pulse cycloconverter topology. (orig.)

  7. Designing asynchronous circuits using NULL convention logic (NCL)

    CERN Document Server

    Smith, Scott

    2009-01-01

    Designing Asynchronous Circuits using NULL Convention Logic (NCL) begins with an introduction to asynchronous (clockless) logic in general, and then focuses on delay-insensitive asynchronous logic design using the NCL paradigm. The book details design of input-complete and observable dual-rail and quad-rail combinational circuits, and then discusses implementation of sequential circuits, which require datapath feedback. Next, throughput optimization techniques are presented, including pipelining, embedding registration, early completion, and NULL cycle reduction. Subsequently, low-power design

  8. DIRECT FREQUENCY CONVERTER WITH ARTIFICIAL AND NATURAL COMMUTATION FOR BRUSHLESS ASYNCHRONIZED MACHINES

    Directory of Open Access Journals (Sweden)

    А.М. Galynovskiy

    2015-11-01

    Full Text Available The comparative analysis of direct frequency converters with artificial and natural- switching term of the cyclical control algorithm is presented; the recommendations for their using in brushless asynchronized machines with three-phase winding are developed. Converters with a limited number of full-controlled valves have large losses in safety circuits of gates, they can be used in system of automatic excitation control. The best quality of voltage and current load are provided by converters with natural commutation using modulated input voltage, the combined potential compounds windings supply and the combined method of thyristor controlling. When the load is divided into two three-phase groups, an even number of phases of the power supply for single phase of the load are applied the bridge converter circuit. Regulation of the load current is carried out by the excitation current of field exciters and by the control angle of thyristor. Converters can be used in high-power asynchronized motors and generators. In asynchronized compensators it is possible to use diode-thyristor converters without transmitting the control signals to the rotating part. The frequency converters without modulation of input voltage have the smallest increase in rated capacity of power supply. However, they have a low quality form of the output voltage at high power factor of load.

  9. Designing Asynchronous Circuits for Low Power: An IFIR Filter

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1999-01-01

    This paper addresses the design of asynchronous circuits for low power through an example: a filter bank for a digital hearing aid. The asynchronous design re-implements an existing synchronous circuit which is used in a commercial product. For comparison, both designs have been fabricated in the...... by numerically small samples). Apart from the improved RAM design, these measures are only viable in an asynchronous design. The principles and techniques explained in this paper are of a general nature, and they apply to the design of asynchronous low-power digital signal-processing circuits in a...

  10. EPOS for Coordination of Asynchronous Sensor Webs Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop, integrate, and deploy software-based tools to coordinate asynchronous, distributed missions and optimize observation planning spanning simultaneous...

  11. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  12. Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

    Science.gov (United States)

    Smith, S. C.; Al-Assadi, W. K.; Di, J.

    2010-01-01

    As demand increases for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design…

  13. Asynchronous Learning Sources in a High-Tech Organization

    Science.gov (United States)

    Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

    2009-01-01

    Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

  14. Teaching Presence and Communication Timeliness in Asynchronous Online Courses

    Science.gov (United States)

    Skramstad, Erik; Schlosser, Charles; Orellana, Anymir

    2012-01-01

    This study examined student perceptions of teaching presence and communication timeliness in asynchronous online courses. Garrison, Anderson, and Archer's (2000) community of inquiry model provided the framework for the survey research methodology used. Participants were 59 student volunteers taking 1 or more asynchronous online graduate courses.…

  15. Selective particle capture by asynchronously beating cilia

    Science.gov (United States)

    Ding, Yang; Kanso, Eva

    2015-12-01

    Selective particle filtration is fundamental in many engineering and biological systems. For example, many aquatic microorganisms use filter feeding to capture food particles from the surrounding fluid, using motile cilia. One of the capture strategies is to use the same cilia to generate feeding currents and to intercept particles when the particles are on the downstream side of the cilia. Here, we develop a 3D computational model of ciliary bands interacting with flow suspended particles and calculate particle trajectories for a range of particle sizes. Consistent with experimental observations, we find optimal particle sizes that maximize capture rate. The optimal size depends nonlinearly on cilia spacing and cilia coordination, synchronous vs. asynchronous. These parameters affect the cilia-generated flow field, which in turn affects particle trajectories. The low capture rate of smaller particles is due to the particles' inability to cross the flow streamlines of neighboring cilia. Meanwhile, large particles have difficulty entering the sub-ciliary region once advected downstream, also resulting in low capture rates. The optimal range of particle sizes is enhanced when cilia beat asynchronously. These findings have potentially important implications on the design and use of biomimetic cilia in processes such as particle sorting in microfluidic devices.

  16. Commande optimale à flux libre des machines asynchrones

    Science.gov (United States)

    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

  17. Asynchronous Parallel Evolutionary Algorithms for Constrained Optimizations

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Recently Guo Tao proposed a stochastic search algorithm in his PhD thesis for solving function op-timization problems. He combined the subspace search method (a general multi-parent recombination strategy) with the population hill-climbing method. The former keeps a global search for overall situation,and the latter keeps the convergence of the algorithm. Guo's algorithm has many advantages ,such as the sim-plicity of its structure ,the higher accuracy of its results, the wide range of its applications ,and the robustness of its use. In this paper a preliminary theoretical analysis of the algorithm is given and some numerical experiments has been done by using Guo's algorithm for demonstrating the theoretical results. Three asynchronous paral-lel evolutionary algorithms with different granularities for MIMD machines are designed by parallelizing Guo's Algorithm.

  18. Fault tolerant vector control of induction motor drive

    Science.gov (United States)

    Odnokopylov, G.; Bragin, A.

    2014-10-01

    For electric composed of technical objects hazardous industries, such as nuclear, military, chemical, etc. an urgent task is to increase their resiliency and survivability. The construction principle of vector control system fault-tolerant asynchronous electric. Displaying recovery efficiency three-phase induction motor drive in emergency mode using two-phase vector control system. The process of formation of a simulation model of the asynchronous electric unbalance in emergency mode. When modeling used coordinate transformation, providing emergency operation electric unbalance work. The results of modeling transient phase loss motor stator. During a power failure phase induction motor cannot save circular rotating field in the air gap of the motor and ensure the restoration of its efficiency at rated torque and speed.

  19. Stand-Alone and Hybrid Positioning Using Asynchronous Pseudolites

    Directory of Open Access Journals (Sweden)

    Ciro Gioia

    2014-12-01

    Full Text Available global navigation satellite system (GNSS receivers are usually unable to achieve satisfactory performance in difficult environments, such as open-pit mines, urban canyons and indoors. Pseudolites have the potential to extend GNSS usage and significantly improve receiver performance in such environments by providing additional navigation signals. This also applies to asynchronous pseudolite systems, where different pseudolites operate in an independent way. Asynchronous pseudolite systems require, however, dedicated strategies in order to properly integrate GNSS and pseudolite measurements. In this paper, several asynchronous pseudolite/GNSS integration strategies are considered: loosely- and tightly-coupled approaches are developed and combined with pseudolite proximity and receiver signal strength (RSS-based positioning. The performance of the approaches proposed has been tested in different scenarios, including static and kinematic conditions. The tests performed demonstrate that the methods developed are effective techniques for integrating heterogeneous measurements from different sources, such as asynchronous pseudolites and GNSS.

  20. TCDQ-TCT retraction and losses during asynchronous beam dump

    CERN Document Server

    Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

    2016-01-01

    The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

  1. A Comparison of Distance Education Competencies Delivered Synchronously and Asynchronously.

    Science.gov (United States)

    Dooley, Kim E.; Lindner, James R.; Richards, Lance J.

    2003-01-01

    Comparison of agriculture courses delivered synchronously via interactive television (20 students) and asynchronously via the Web (22 students) showed similar achievement of core distance education competencies: adult learning, technology knowledge, instructional design, communication skills, graphic design, administration) regardless of delivery…

  2. Solving SAT and Hamiltonian Cycle Problem Using Asynchronous P Systems

    Science.gov (United States)

    Tagawa, Hirofumi; Fujiwara, Akihiro

    In the present paper, we consider fully asynchronous parallelism in membrane computing, and propose two asynchronous P systems for the satisfiability (SAT) and Hamiltonian cycle problem. We first propose an asynchronous P system that solves SAT with n variables and m clauses, and show that the proposed P system computes SAT in O(mn2n) sequential steps or O(mn) parallel steps using O(mn) kinds of objects. We next propose an asynchronous P system that solves the Hamiltonian cycle problem with n nodes, and show that the proposed P system computes the problem in O(n!) sequential steps or O(n2) parallel steps using O(n2) kinds of objects.

  3. Asynchronous FSK wireless data traffic interface circuit design

    International Nuclear Information System (INIS)

    This article gives a practical interface circuit, which is able to conduct asynchronous wireless data communication through data transfer broadcasting station. And the circuit's design as well as its applications are introduced. (authors)

  4. Dynamic interactions between asynchronous grids interconnected through an MTDC system

    OpenAIRE

    Endegnanew, Atsede Gualu; Beerten, Jef; Uhlen, Kjetil

    2015-01-01

    The large-scale integration of renewable energy sources in the power system, combined with the need for an increased transmission capacity has led to a growing interest in multi-terminal high voltage dc (MTDC) grids. In the future, these grids will be integrated with different existing asynchronous ac grids, eventually resulting in hybrid AC/DC power systems. This paper investigates interactions between asynchronous ac grids in a hybrid AC/DC power system. In the study, a symmetrical monopola...

  5. Tidal Flows in asynchronous binaries: The beta-factor

    CERN Document Server

    Koenigsberger, Gloria

    2013-01-01

    We discuss the potential role that tidal flows in asynchronous binary stars may play in transporting chemically enriched material from deep layers towards the surface and the corresponding observational consequences of these processes. We suggest that the time-dependent velocity field induced by asynchronous rotation may contribute significantly to the mixing, thus providing a channel for the formation of chemically enriched slowly rotating massive stars.

  6. Ternary Tree Asynchronous Interconnect Network for GALS' SOC

    Directory of Open Access Journals (Sweden)

    Vivek E. Khetade

    2013-03-01

    Full Text Available Interconnect fabric requires easy integration of computational block operating with unrelated clocks.Thispaper presents asynchronous interconnect with ternary tree asynchronous network for GloballyAsynchronous Locally Synchronous (GALS system-on-chip (SOC. Here architecture is proposed forinterconnection with ternary tree asynchronous network where ratio of number NOC design unit andnumber of router is 4:1,6:2, 8:3,10:4 etc .It is scalable for any number of NOC design unit. It offersaneasy integration of different clock domain with lowcommunication overhead .NOC design unit for GALS‘SOC is formulated by wrapping synchronous module with input port along with input port controller,output port along with output port controller and local clock generator. It creates the interface betweensynchronous to asynchronous and asynchronous to synchronous. For this purpose four port asynchronousrouters is designed with routing element and outputarbitration and buffering with micro-pipeline. Thisinterconnect fabric minimizes silicon area, minimize Latency and maximize throughput. Here functionalmodel is made for TTAN and application MPEG4 is mapped on the Network .Desired traffic pattern isgenerated and performance of the network is evaluated. Significant improvement in the networkperformance parameter has been observed.

  7. Asynchronous event-based hebbian epipolar geometry.

    Science.gov (United States)

    Benosman, Ryad; Ieng, Sio-Hoï; Rogister, Paul; Posch, Christoph

    2011-11-01

    Epipolar geometry, the cornerstone of perspective stereo vision, has been studied extensively since the advent of computer vision. Establishing such a geometric constraint is of primary importance, as it allows the recovery of the 3-D structure of scenes. Estimating the epipolar constraints of nonperspective stereo is difficult, they can no longer be defined because of the complexity of the sensor geometry. This paper will show that these limitations are, to some extent, a consequence of the static image frames commonly used in vision. The conventional frame-based approach suffers from a lack of the dynamics present in natural scenes. We introduce the use of neuromorphic event-based--rather than frame-based--vision sensors for perspective stereo vision. This type of sensor uses the dimension of time as the main conveyor of information. In this paper, we present a model for asynchronous event-based vision, which is then used to derive a general new concept of epipolar geometry linked to the temporal activation of pixels. Practical experiments demonstrate the validity of the approach, solving the problem of estimating the fundamental matrix applied, in a first stage, to classic perspective vision and then to more general cameras. Furthermore, this paper shows that the properties of event-based vision sensors allow the exploration of not-yet-defined geometric relationships, finally, we provide a definition of general epipolar geometry deployable to almost any visual sensor. PMID:21954205

  8. Rapid, generalized adaptation to asynchronous audiovisual speech.

    Science.gov (United States)

    Van der Burg, Erik; Goodbourn, Patrick T

    2015-04-01

    The brain is adaptive. The speed of propagation through air, and of low-level sensory processing, differs markedly between auditory and visual stimuli; yet the brain can adapt to compensate for the resulting cross-modal delays. Studies investigating temporal recalibration to audiovisual speech have used prolonged adaptation procedures, suggesting that adaptation is sluggish. Here, we show that adaptation to asynchronous audiovisual speech occurs rapidly. Participants viewed a brief clip of an actor pronouncing a single syllable. The voice was either advanced or delayed relative to the corresponding lip movements, and participants were asked to make a synchrony judgement. Although we did not use an explicit adaptation procedure, we demonstrate rapid recalibration based on a single audiovisual event. We find that the point of subjective simultaneity on each trial is highly contingent upon the modality order of the preceding trial. We find compelling evidence that rapid recalibration generalizes across different stimuli, and different actors. Finally, we demonstrate that rapid recalibration occurs even when auditory and visual events clearly belong to different actors. These results suggest that rapid temporal recalibration to audiovisual speech is primarily mediated by basic temporal factors, rather than higher-order factors such as perceived simultaneity and source identity. PMID:25716790

  9. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Baines, John; The ATLAS collaboration

    2016-01-01

    In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

  10. Multiple-input single-output closed-loop isometric force control using asynchronous intrafascicular multi-electrode stimulation.

    Science.gov (United States)

    Frankel, Mitchell A; Dowden, Brett R; Mathews, V John; Normann, Richard A; Clark, Gregory A; Meek, Sanford G

    2011-06-01

    Although asynchronous intrafascicular multi-electrode stimulation (IFMS) can evoke fatigue-resistant muscle force, a priori determination of the necessary stimulation parameters for precise force production is not possible. This paper presents a proportionally-modulated, multiple-input single-output (MISO) controller that was designed and experimentally validated for real-time, closed-loop force-feedback control of asynchronous IFMS. Experiments were conducted on anesthetized felines with a Utah Slanted Electrode Array implanted in the sciatic nerve, either acutely or chronically ( n = 1 for each). Isometric forces were evoked in plantar-flexor muscles, and target forces consisted of up to 7 min of step, sinusoidal, and more complex time-varying trajectories. The controller was successful in evoking steps in force with time-to-peak of less than 0.45 s, steady-state ripple of less than 7% of the mean steady-state force, and near-zero steady-state error even in the presence of muscle fatigue, but with transient overshoot of near 20%. The controller was also successful in evoking target sinusoidal and complex time-varying force trajectories with amplitude error of less than 0.5 N and time delay of approximately 300 ms. This MISO control strategy can potentially be used to develop closed-loop asynchronous IFMS controllers for a wide variety of multi-electrode stimulation applications to restore lost motor function. PMID:21385670

  11. Effect of asynchronous updating on the stability of cellular automata

    International Nuclear Information System (INIS)

    Highlights: ► An upper bound on the Lyapunov exponent of asynchronously updated CA is established. ► The employed update method has repercussions on the stability of CAs. ► A decision on the employed update method should be taken with care. ► Substantial discrepancies arise between synchronously and asynchronously updated CA. ► Discrepancies between different asynchronous update schemes are less pronounced. - Abstract: Although cellular automata (CAs) were conceptualized as utter discrete mathematical models in which the states of all their spatial entities are updated simultaneously at every consecutive time step, i.e. synchronously, various CA-based models that rely on so-called asynchronous update methods have been constructed in order to overcome the limitations that are tied up with the classical way of evolving CAs. So far, only a few researchers have addressed the consequences of this way of updating on the evolved spatio-temporal patterns, and the reachable stationary states. In this paper, we exploit Lyapunov exponents to determine to what extent the stability of the rules within a family of totalistic CAs is affected by the underlying update method. For that purpose, we derive an upper bound on the maximum Lyapunov exponent of asynchronously iterated CAs, and show its validity, after which we present a comparative study between the Lyapunov exponents obtained for five different update methods, namely one synchronous method and four well-established asynchronous methods. It is found that the stability of CAs is seriously affected if one of the latter methods is employed, whereas the discrepancies arising between the different asynchronous methods are far less pronounced and, finally, we discuss the repercussions of our findings on the development of CA-based models.

  12. EEG-based asynchronous BCI control of a car in 3D virtual reality environments

    Institute of Scientific and Technical Information of China (English)

    ZHAO QiBin; ZHANG LiQing; CICHOCKI Andrzej

    2009-01-01

    Brain computer interface (BCl) aims at creating new communication channels without depending on brain's normal output channels of peripheral nerves and muscles.However,natural and sophisticated interactions manner between brain and computer still remain challenging.In this paper,we investigate how the duration of event-related desynchronization/synchronization (ERD/ERS) caused by motor im-agery (MI) can be modulated and used as an additional control parameter beyond simple binary deci-sions.Furthermore,using the non-time-locked properties of sustained (de)synchronization,we have developed an asynchronous BCl system for driving a car in 3D virtual reality environment (VRE) based on cumulative incremental control strategy.The extensive real time experiments confirmed that our new approach is able to drive smoothly a virtual car within challenging VRE only by the MI tasks with-out involving any muscular activities.

  13. Robot drive mechanism uses conventional electric motors

    Science.gov (United States)

    Demchenko, I.

    1986-02-01

    The development and use of three phase asynchronous electric motors in robot technology are presented. The mechanical arm of a robot has as many drives as it has joints. Manipulators in use in modern industry must have six to nine degrees of mobility, and experimental prototypes with 18 coordinates of movement are already developed. A simple, common, and inexpensive industrial electric motor is proposed for use in the robots. This motor was previously considered unsuitable for delicate work because of its low precision in executing commands and the difficulty in controlling it. Control methods were developed to overcome this difficulty. Integrated microcircuits and a power converter control the operation of the single motor. A cassette made up of six units controls the operation of the whole mechanical arm. This cassette is linked with the brain of the robot (a microprocessor system or microcomputer).

  14. Efficiency asynchronous application programming language Python

    OpenAIRE

    Толстікова, О. В.; Національний авіаційний університет; Мирошниченко, І. С.; Національний авіаційний університет; Коцюр, А. Б.; Національний авіаційний університет

    2016-01-01

    Consider tools that implement asynchronous programming in Python and allow more efficient use ofasynchronous programming applications. The efficiency of the module asyncio (PEP 3156) incomparison with classical spivprohramamy Рассмотрены инструменты, которые реализуют асинхронное программирование в языкеPython и позволяют повысить эффективность использования программирования асинхронныхприложений. Показана эффективность работы модуля asyncio (PEP 3156) по сравнению с классическими сопрогра...

  15. IHadoop: Asynchronous iterations for MapReduce

    KAUST Repository

    Elnikety, Eslam Mohamed Ibrahim

    2011-11-01

    MapReduce is a distributed programming frame-work designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter-iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This paper also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  16. Asynchronous event-based corner detection and matching.

    Science.gov (United States)

    Clady, Xavier; Ieng, Sio-Hoi; Benosman, Ryad

    2015-06-01

    This paper introduces an event-based luminance-free method to detect and match corner events from the output of asynchronous event-based neuromorphic retinas. The method relies on the use of space-time properties of moving edges. Asynchronous event-based neuromorphic retinas are composed of autonomous pixels, each of them asynchronously generating "spiking" events that encode relative changes in pixels' illumination at high temporal resolutions. Corner events are defined as the spatiotemporal locations where the aperture problem can be solved using the intersection of several geometric constraints in events' spatiotemporal spaces. A regularization process provides the required constraints, i.e. the motion attributes of the edges with respect to their spatiotemporal locations using local geometric properties of visual events. Experimental results are presented on several real scenes showing the stability and robustness of the detection and matching. PMID:25828960

  17. Molecular mechanisms for synchronous, asynchronous, and spontaneous neurotransmitter release.

    Science.gov (United States)

    Kaeser, Pascal S; Regehr, Wade G

    2014-01-01

    Most neuronal communication relies upon the synchronous release of neurotransmitters, which occurs through synaptic vesicle exocytosis triggered by action potential invasion of a presynaptic bouton. However, neurotransmitters are also released asynchronously with a longer, variable delay following an action potential or spontaneously in the absence of action potentials. A compelling body of research has identified roles and mechanisms for synchronous release, but asynchronous release and spontaneous release are less well understood. In this review, we analyze how the mechanisms of the three release modes overlap and what molecular pathways underlie asynchronous and spontaneous release. We conclude that the modes of release have key fusion processes in common but may differ in the source of and necessity for Ca(2+) to trigger release and in the identity of the Ca(2+) sensor for release. PMID:24274737

  18. A Novel Multiuser Detector for Asynchronous CDMA System

    Institute of Scientific and Technical Information of China (English)

    LIANGXint; SHANGYong; LIANGQinglin; XIANGHaige

    2004-01-01

    The decorrelating and the MMSE (Minimum mean square error) multiuser detector for asynchronous CDMA (Code devision multiple access) system are ideally anticausal infinite memory-length detectors. Asa result~ in practice they have to be approximately implemented with finite-memory structure, and the process delay in detection is unavoidable. Based on the analysis of a new signal model for asynchronous system, a novel multiuser detector for asynchronous CDMA system is proposed in this paper~ which is termed as DF-IC-MMSE (Decision ,feedback interference cancellation-MMSE) detector. It's the detection statistics that makes the DF-IC-MMSE-detector basically different from other traditional ones. The DF-IC-MMSE detector can be ideally implemented with Causal finite memory-length structure, and cause no delay in symbol detection. Simulations show that the performance of DF-IC-MMSE detector is almost identical to that of the ideal MMSE detector.

  19. A Loosely Synchronizing Asynchronous Router for TDM-Scheduled NOCs

    DEFF Research Database (Denmark)

    Kotleas, Ioannis; Humphreys, Dean; Sørensen, Rasmus Bo;

    2014-01-01

    This paper presents an asynchronous router design for use in time-division-multiplexed (TDM) networks-on-chip. Unlike existing synchronous, mesochronous and asynchronous router designs with similar functionality, the router is able to silently skip over cycles/TDM-slots where no traffic is...... scheduled and hence avoid all switching activity in the idle links and router ports. In this way switching activity is reduced to the minimum possible amount. The fact that this relaxed synchronization is sufficient to implement TDM scheduling represents a contribution at the conceptual level. The idea can...... only be implemented using asynchronous circuit techniques. To this end, the paper explores the use of “click-element” templates. Click-element templates use only flipflops and conventional gates, and this greatly simplifies the design process when using conventional EDA tools and standard cell...

  20. Design and Analysis of Drive System with Slip Ring Induction Motor for Electric Traction in India

    OpenAIRE

    Nagamani Chandra sekara; Somanatham R; Chaitanya Kumar U

    2015-01-01

    The use of Squirrel Cage for Traction has revolutionised the motive power of a Locomotive. The Asynchronous Motor is rugged with high starting Torque, has a very smooth Voltage and Speed control as compared to a DC Series Motor. When looking at the Traction perspective, a Slip Ring Induction Motor can be an alternative to the Squirrel Cage Motor as it has higher starting Torque and better efficiency than a Squirrel Cage Motor. the Slip Power Recovery scheme also plays a proactive role as ther...

  1. Current Trends in High-Level Synthesis of Asynchronous Circuits

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2009-01-01

    .g. the Haste/TiDE tool from Handshake Solutions or the Balsa tool from the University of Manchester. The aims are to add highlevel synthesis capabilities to these tools and to extend the tools such that a wider range of (higher speed) micro-architectures can be generated. Another branch of research takes...... a conventional synchronous circuit as the starting point, and then adds some form of handshake-based flow-control. One approach keeps the global clock and implements discrete-time asynchronous operation. Another approach substitutes the clocked registers by asynchronous handshake-registers, thus...

  2. On the theoretical gap between synchronous and asynchronous MPC protocols

    DEFF Research Database (Denmark)

    Beerliová-Trubíniová, Zuzana; Hirt, Martin; Nielsen, Jesper Buus

    2010-01-01

    Multiparty computation (MPC) protocols among n parties secure against t active faults are known to exist if and only if t < n/2, when the channels are synchronous, and t < n/3, when the channels are asynchronous, respectively.   In this work we analyze the gap between these bounds, and show that in...... the cryptographic setting (with setup), the sole reason for it is the distribution of inputs: given an oracle for input distribution, cryptographically-secure asynchronous MPC is possible with the very same condition as synchronous MPC, namely t < n/2. We do not know whether the gaps in other security...

  3. Asynchronous updating of threshold-coupled chaotic neurons

    Indian Academy of Sciences (India)

    Manish Dev Shirmali; Sudeshna Sinha; Kazuyuki Aihara

    2008-06-01

    We study a network of chaotic model neurons incorporating threshold activated coupling. We obtain a wide range of spatiotemporal patterns under varying degrees of asynchronicity in the evolution of the neuronal components. For instance, we find that sequential updating of threshold-coupled chaotic neurons can yield dynamical switching of the individual neurons between two states. So varying the asynchronicity in the updating scheme can serve as a control mechanism to extract different responses, and this can have possible applications in computation and information processing.

  4. DPA on quasi delay insensitive asynchronous circuits : formalization and improvement

    CERN Document Server

    Bouesse, G F; Dumont, S; Germain, F

    2007-01-01

    The purpose of this paper is to formally specify a flow devoted to the design of Differential Power Analysis (DPA) resistant QDI asynchronous circuits. The paper first proposes a formal modeling of the electrical signature of QDI asynchronous circuits. The DPA is then applied to the formal model in order to identify the source of leakage of this type of circuits. Finally, a complete design flow is specified to minimize the information leakage. The relevancy and efficiency of the approach is demonstrated using the design of an AES crypto-processor.

  5. 小波变换及其在异步电动机 转子断路故障诊断中的应用%Wavelet transform and its application in the fault diagnosis for the open-circuit rotor of asynchronous motor

    Institute of Scientific and Technical Information of China (English)

    董爱华; 王福忠; 艾永乐; 王芳

    2001-01-01

    Wavelet transform with the good partial characteristic in time-frequency regions is an effective way to make time-frequency analysis and processing of the signals.It has mainly discussed the basic theory of wavelet transform,and introduced the principle of the diagnosis in the open-circuit rotor of asychronous motor with wavelet transform.The construction of signal detection circuit is given as well.%小波变换具有良好的时-频局部化特性,是信号的时-频域分析和处理的有效方法.简要论述了有关小波变换的基本理论,介绍了小波变换在异步电动机转子断路故障诊断的原理,给出了信号检测电路的组成.

  6. The Influence of Asynchronous Video Communication on Learner Social Presence: A Narrative Analysis of Four Cases

    Science.gov (United States)

    Borup, Jered; West, Richard E.; Graham, Charles R.

    2013-01-01

    Online courses are increasingly using asynchronous video communication. However, little is known about how asynchronous video communication influences students' communication patterns. This study presents four narratives of students with varying characteristics who engaged in asynchronous video communication. The extrovert valued the efficiency of…

  7. Asynchronous Assessment in a Large Lecture Marketing Course

    Science.gov (United States)

    Downey, W. Scott; Schetzsle, Stacey

    2012-01-01

    Asynchronous assessment, which includes quizzes or exams online or outside class, offers marketing educators an opportunity to make more efficient use of class time and to enhance students' learning experiences by giving them more flexibility and choice in their assessment environment. In this paper, we examine the performance difference between…

  8. Structure-Based Deadlock Checking of Asynchronous Circuits

    Institute of Scientific and Technical Information of China (English)

    Hong-Guang Ren; Zhi-Ying Wang; Doug Edwards

    2011-01-01

    It is important to verify the absence of deadlocks in asynchronous circuits.Much previous work relies on a reachability analysis of the circuits' states,with the use of binary decision diagrams (BDDs) or Petri nets to model the behaviors of circuits.This paper presents an alternative approach focusing on the structural properties of well-formed asynchronous circuits that will never suffer deadlocks.A class of data-driven asynchronous pipelines is targeted in this paper,which can be viewed as a network of basic components connected by handshake channels.The sufficient and necessary conditions for a component network consisting of Steer,Merge,Fork and Join are given.The slack elasticity of the channels is analyzed in order to introduce pipelining.As an application,a deadlock checking method is implemented in a syntax-directed asynchronous design tool - Teak.The proposed method shows a great runtime advantage when compared against previous Petri net based verification tools.

  9. APPLICATION OF ASYNCHRONOUS GENERATOR FOR INDUCTION MOTOR’S FEEDING

    OpenAIRE

    Bogdan A. V.; Ilchenko Y. A.; Sobol A. N.; Erokhov M. V.

    2014-01-01

    In the article, the following items are represented: mathematical formulation of system including: asynchronous generator with cage rotor, condenser’s for excitation, induction load. Electromagnetic and electromechanical processes of induction motor’s connecting and feeding are described. Equations of voltage stability, equations of current, equations of rotor are used for describing of electricity circuits of generator

  10. Analysis of the Relevance of Posts in Asynchronous Discussions

    Science.gov (United States)

    Azevedo, Breno T.; Reategui, Eliseo; Behar, Patrícia A.

    2014-01-01

    This paper presents ForumMiner, a tool for the automatic analysis of students' posts in asynchronous discussions. ForumMiner uses a text mining system to extract graphs from texts that are given to students as a basis for their discussion. These graphs contain the most relevant terms found in the texts, as well as the relationships between them.…

  11. GPU-Based Asynchronous Global Optimization with Particle Swarm

    International Nuclear Information System (INIS)

    The recent upsurge in research into general-purpose applications for graphics processing units (GPUs) has made low cost high-performance computing increasingly more accessible. Many global optimization algorithms that have previously benefited from parallel computation are now poised to take advantage of general-purpose GPU computing as well. In this paper, a global parallel asynchronous particle swarm optimization (PSO) approach is employed to solve three relatively complex, realistic parameter estimation problems in which each processor performs significant computation. Although PSO is readily parallelizable, memory bandwidth limitations with GPUs must be addressed, which is accomplished by minimizing communication among individual population members though asynchronous operations. The effect of asynchronous PSO on robustness and efficiency is assessed as a function of problem and population size. Experiments were performed with different population sizes on NVIDIA GPUs and on single-core CPUs. Results for successful trials exhibit marked speedup increases with the population size, indicating that more particles may be used to improve algorithm robustness while maintaining nearly constant time. This work also suggests that asynchronous operations on the GPU may be viable in stochastic population-based algorithms to increase efficiency without sacrificing the quality of the solutions.

  12. Cyber Asynchronous versus Blended Cyber Approach in Distance English Learning

    Science.gov (United States)

    Ge, Zi-Gang

    2012-01-01

    This study aims to compare the single cyber asynchronous learning approach with the blended cyber learning approach in distance English education. Two classes of 70 students participated in this study, which lasted one semester of about four months, with one class using the blended approach for their English study and the other only using the…

  13. Psychological Type and Asynchronous Written Dialogue in Adult Learning

    Science.gov (United States)

    Lin, Lin; Cranton, Patricia; Bridglall, Beatrice

    2005-01-01

    This study explores how adults learn from asynchronous written dialogue through the lens of psychological type preferences. We asked participants to discover their dominant and auxiliary psychological preferences using the Personal Empowerment through Type inventory. Participants then completed an open-ended survey in which they described their…

  14. Asynchronous Linking in a Service –Oriented Architecture.

    OpenAIRE

    Vivek, Sanjay; Tso, Kenneth; Thompson, Mark; De Roure, David

    2002-01-01

    In this paper, we identify research issues in the development of system infrastructure support for asynchronous linkservices in a service-oriented architecture. We explore the suitability and applicability of using MQSeries Everyplace to provide a messaging backbone for linkservices that increases reliability, fault tolerance, and scalability. We identify and discuss some important problems and research issues related to this approach.

  15. Abstracting Asynchronous Multi-Valued Networks: An Initial Investigation

    CERN Document Server

    Steggles, L Jason

    2011-01-01

    Multi-valued networks provide a simple yet expressive qualitative state based modelling approach for biological systems. In this paper we develop an abstraction theory for asynchronous multi-valued network models that allows the state space of a model to be reduced while preserving key properties of the model. The abstraction theory therefore provides a mechanism for coping with the state space explosion problem and supports the analysis and comparison of multi-valued networks. We take as our starting point the abstraction theory for synchronous multi-valued networks which is based on the finite set of traces that represent the behaviour of such a model. The problem with extending this approach to the asynchronous case is that we can now have an infinite set of traces associated with a model making a simple trace inclusion test infeasible. To address this we develop a decision procedure for checking asynchronous abstractions based on using the finite state graph of an asynchronous multi-valued network to reas...

  16. Asynchronous Multi-Party Computation with Quadratic Communication

    DEFF Research Database (Denmark)

    Hirt, Martin; Nielsen, Jesper Buus; Przydatek, Bartosz

    2008-01-01

    We present an efficient protocol for secure multi-party computation in the asynchronous model with optimal resilience. For n parties, up to t < n/3 of them being corrupted, and security parameter κ, a circuit with c gates can be securely computed with communication complexity O(cn^2k) bits, which...

  17. Asynchronous rotation scan for synthetic aperture interferometric radiometer

    Institute of Scientific and Technical Information of China (English)

    WU Ji; ZHANG Cheng; LIU Hao; SUN WeiYing

    2009-01-01

    Synthetic aperture interferometric technique has wide applications in optics, radio astronomy and mi-crowave remote sensing areas. With the increasing demands of high resolution imaging observation, a new time-sharing sampling scheme of asynchronous rotation scan is proposed to meet the technical challenge of achieving a large equivalent aperture and overcome the operating barriers of space borne application. This configuration is basically composed by two asynchronously and concentrically ro-tating antenna groups, whose revolving radii and speeds are different. The synthetic aperture system with asynchronous rotation scanning scheme can effectively solve the trade-off problem of system complexity, and greatly simplify the system hardware at the cost of sacrificing a certain time resolution. The basic rules and design methods of asynchronous rotation scan are investigated The Gridding method is introduced to inverse the spiral sampling data for image reconstruction. The potential ap-plications of geostationary orbit (GEO) earth observation and solar polar orbit (SPO) plasma cloud observation are explored with numerical simulations to validate the significance and feasibility of this new imaging configuration.

  18. Asynchronous rotation scan for synthetic aperture interferometric radiometer

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Synthetic aperture interferometric technique has wide applications in optics,radio astronomy and mi-crowave remote sensing areas.With the increasing demands of high resolution imaging observation,a new time-sharing sampling scheme of asynchronous rotation scan is proposed to meet the technical challenge of achieving a large equivalent aperture and overcome the operating barriers of space borne application.This configuration is basically composed by two asynchronously and concentrically ro-tating antenna groups,whose revolving radii and speeds are different.The synthetic aperture system with asynchronous rotation scanning scheme can effectively solve the trade-off problem of system complexity,and greatly simplify the system hardware at the cost of sacrificing a certain time resolution.The basic rules and design methods of asynchronous rotation scan are investigated The Gridding method is introduced to inverse the spiral sampling data for image reconstruction.The potential ap-plications of geostationary orbit(GEO)earth observation and solar polar orbit(SPO)plasma cloud observation are explored with numerical simulations to validate the significance and feasibility of this new imaging configuration.

  19. METHOD OF DETERMINING THE START TIME OF INDUCTION MOTORS IN THE CONTROL OF RESISTOR-THYRISTOR MODULES

    OpenAIRE

    V.I. Lobov; Lobova, K. V.

    2015-01-01

    Purpose. An electric general-purpose drive with asynchronous motor is proposed. For motor control in stator and rotor, circuits used resistors and thyristors. These elements included together in various ways. This allows to get a variety of power converter circuit with resistor-thyristor modules. Methodology. Taking into account the technical requirements for industrial machinery developed an analytical method for determining the run-up controlled induction motor. Formed starting modes by cha...

  20. Thermal Modelling for the Motor in Semi-hermetic Screw Refrigeration Compressor under Part-load Conditions

    OpenAIRE

    Chen, Wenqing; Shen, Jiubing; He, ZhiLong; Wu, Huagen; Xing, Ziwen

    2012-01-01

    Semi-hermetic screw refrigeration compressor is mostly driven by a three phase asynchronous induction motor with its squirrel cage rotor attached to the shaft of the compressor helical male rotor. The motor is cooled by low temperature refrigerant coming from evaporator before it is inspired into compressor suction port. In order to investigate cooling effects of the motor and performance of the compressor under part-load conditions, a lumped parameter model describing heat transfer character...

  1. Biomolecular motors

    Directory of Open Access Journals (Sweden)

    Henry Hess

    2005-12-01

    Here, we give a brief introduction to molecular motors, with an emphasis on motor proteins, describe the challenges in interfacing these bionanomachines with an artificial environment, and provide examples of emerging applications.

  2. Asynchronous Cooperative e-Learning System and Its Evaluation

    Science.gov (United States)

    Eto, Kazuhiro; Miyoshi, Takumi

    Much attention has been attracted to collaborative learning on an e-learning system. However, it is difficult to implement the collaborative environment to an asynchronous e-learning system since collaboration would be realized only when learners join the system at the same time. On the other hand, cooperative learning has been proposed. In this method, learners can study on their own pace without making mutual agreement but with receiving cognitive information from others. In this paper, the authors have developed the asynchronous cooperative e-learning system that provides learners' attendance and studying progress as the cognitive information. The subjective evaluation experiments show that our system is slightly inferior to the synchronous collaborative e-learning system, but it can motivate the learners more than the conventional system.

  3. A STUDY ON ASYNCHRONOUS SERIAL COMMUNICATON BETWEEN COMPONENTS IN AUTOMOBILES

    OpenAIRE

    ŞAHİN, Yaşar Güneri

    2010-01-01

    ABSTRACTIn connection with the developments in the automobile sector, the number of in-automobile components, the amount of cable used for providing in-automobile communication between these components and costs are increased gradually. In this study, a method is presented in which asynchronous serial connection is used for decreasing the initial and maintenance costs by means of decreasing the amount of cables used in middle and lower class automobiles. The electronic circuits required to es...

  4. Diversity Multiplexing Tradeoff of Asynchronous Cooperative Relay Networks

    CERN Document Server

    Krishnakumar, R N; Kumar, P Vijay

    2008-01-01

    The assumption of nodes in a cooperative communication relay network operating in synchronous fashion is often unrealistic. In the present paper, we consider two different models of asynchronous operation in cooperative-diversity networks experiencing slow fading and examine the corresponding diversity-multiplexing tradeoffs (DMT). For both models, we propose protocols and distributed space-time codes that asymptotically achieve the transmit diversity bound for all multiplexing gains and for any number of relays.

  5. Indoor Positioning for Smartphones Using Asynchronous Ultrasound Trilateration

    OpenAIRE

    James D. Carswell; Viacheslav Filonenko; Charlie Cullen

    2013-01-01

    Modern smartphones are a great platform for Location Based Services (LBS). While outdoor LBS for smartphones has proven to be very successful, indoor LBS for smartphones has not yet fully developed due to the lack of an accurate positioning technology. In this paper we present an accurate indoor positioning approach for commercial off-the-shelf (COTS) smartphones that uses the innate ability of mobile phones to produce ultrasound, combined with Time-Difference-of-Arrival (TDOA) asynchronous t...

  6. Applications of Maximum Likelihood Algorithm in Asynchronous CDMA Systems

    OpenAIRE

    Xiao, P; Strom, E

    2002-01-01

    We treat the problems of propagation delay and channel estimation as well as data detection of orthogonally modulated signals in an asynchronous DS-CDMA system over fading channels using the maximum likelihood (ML) approach. The overwhelming computational complexity of the ML algorithm makes it unfeasible for implementation. The emphasis of this paper is to reduce its complexity by some approximation methods. The derived approximative ML schemes are compared with conventional algorithms as we...

  7. Asynchronous Discourse Analysis in the Quality of Expected Learning

    OpenAIRE

    Schalk-Quintanar, Ana-Elena; Marcelo-García, Carlos

    2010-01-01

    Universities are gradually implementing virtual learning processes. However, research still remains limited in examining the internal processes that occur in learning in virtual environments. This article presents an investigation that seeks to describe the relationship between the quality of interaction in asynchronous discussion forums in training experiences in e-learning, and the quality of learning offered and achieved. The main objective was to determine how interactions in online envir...

  8. On the convergence time of asynchronous distributed quantized averaging algorithms

    OpenAIRE

    ZHU, MINGHUI; Martinez, Sonia

    2010-01-01

    We come up with a class of distributed quantized averaging algorithms on asynchronous communication networks with fixed, switching and random topologies. The implementation of these algorithms is subject to the realistic constraint that the communication rate, the memory capacities of agents and the computation precision are finite. The focus of this paper is on the study of the convergence time of the proposed quantized averaging algorithms. By appealing to random walks on graphs, we derive ...

  9. Abstractions for asynchronous distributed computing with malicious players

    OpenAIRE

    Vukolic, Marko; Guerraoui, Rachid

    2009-01-01

    In modern distributed systems, failures are the norm rather than the exception. In many cases, these failures are not benign. Settings such as the Internet might incur malicious (also called Byzantine or arbitrary) behavior and asynchrony. As a result, and perhaps not surprisingly, research on asynchronous Byzantine fault-tolerant (BFT) distributed systems is flourishing. Tolerating arbitrary behavior and asynchrony calls for very sophisticated algorithms. This is in particular the case with ...

  10. A novel asynchronous access method with binary interfaces

    OpenAIRE

    Torres-Solis Jorge; Silva Jorge; Chau Tom; Mihailidis Alex

    2008-01-01

    Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches). Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel as...

  11. Design and Implementation of an Asynchronous Pipelined FFT Processor

    OpenAIRE

    Claesson, Jonas

    2003-01-01

    FFT processors are today one of the most important blocks in communication equipment. They are used in everything from broadband to 3G and digital TV to Radio LANs. This master's thesis project will deal with pipelined hardware solutions for FFT processors with long FFT transforms, 1K to 8K points. These processors could be used for instance in OFDM communication systems. The final implementation of the FFT processor uses a GALS (Globally Asynchronous Locally Synchronous) architecture, that ...

  12. Teleoperation system using Asynchronous transfer mode, ATM network

    International Nuclear Information System (INIS)

    This paper examines the application of Asynchronous Transfer Mode (ATM) in a distributed industrial environment such as in teleoperation, which performs real time control manipulation from a remote location. In our study, two models of teleoperation are proposed; the first model is a point to point connection and the second model is through an ATM network. The performance results are analysed as to determine whether the two models can support the teleoperation traffics via simulation using commercial software design tool. (Author)

  13. Motor neglect.

    OpenAIRE

    Laplane, D.; Degos, J D

    1983-01-01

    Motor neglect is characterised by an underutilisation of one side, without defects of strength, reflexes or sensibility. Twenty cases of frontal, parietal and thalamic lesions causing motor neglect, but all without sensory neglect, are reported. It is proposed that the cerebral structures involved in motor neglect are the same as those for sensory neglect and for the preparation of movement. As in sensory neglect, the multiplicity of the structures concerned suggests that this interconnection...

  14. Motor syndromes.

    Science.gov (United States)

    Corea, Francesco; Micheli, Sara

    2012-01-01

    Motor disturbances alone or associated with other focal deficits are the most common symptoms suggesting a neurovascular event. An appropriate clinical assessment of these signs and symptoms may help physicians to better diagnose and to both better treat and predict outcome. In this paper the main clinical features of motor deficit are described together with other motor-related events such as ataxia and movement disturbances. PMID:22377850

  15. Non-Detection of Nova Shells Around Asynchronous Polars

    CERN Document Server

    Pagnotta, Ashley

    2016-01-01

    Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e., their WD and orbital angular velocities are the same). Past nova eruptions are the predicted cause of the asynchronicity, in part due to the fact that one of the APs, V1500 Cyg, was observed to undergo a nova eruption in 1975. We used the Southern African Large Telescope 10m class telescope and the MDM 2.4m Hiltner telescope to search for nova shells around three of the remaining four APs (V1432 Aql, BY Cam, and CD Ind) as well as one Intermediate Polar with a high asynchronicity (EX Hya). We found no evidence of nova shells in any of our images. We therefore cannot say that any of the systems besides V1500 Cyg had nova eruptions, but because not all post-nova systems have detectable shells, we also cannot exclude the possibility of a nova eruption occurring in any of these systems and knocking the rotation out of sync.

  16. Asynchronous Stoichiometric Response in Lithium Iron Phosphate Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Paxton, William A. [State Univ. of New Jersey, Piscataway, NJ (United States); Akdogan, E. Koray [State Univ. of New Jersey, Piscataway, NJ (United States); Savkliyidiz, Ilyas [State Univ. of New Jersey, Piscataway, NJ (United States); Choksi, Ankur U. [State Univ. of New Jersey, Piscataway, NJ (United States); Silver, Scott X. [State Univ. of New Jersey, Piscataway, NJ (United States); Tsakalokos, Thomas [State Univ. of New Jersey, Piscataway, NJ (United States); Zhong, Zhong [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-11

    The operando energy-dispersive x-ray diffraction (EDXRD) was carried out on a newly formed 8 Ah lithium iron phosphate (LiFePO4) battery with the goal of elucidating the origin of asynchronous phase transformation commonly seen with in situ x-ray diffraction studies. The high-energy photons at the NSLS X17B1 beamline allow for penetration into a fully assembled battery and therefore negate any need for a specially designed in situ cell which often uses modified current collectors to minimize x-ray attenuation. Spatially-and-temporally resolved phase-mapping was conducted with a semiquantitative reference intensity ratio (RIR) analysis to estimate the relative abundance of the delithiated phase. The data show an asynchronous response in the stoichiometry versus the electrochemical profile and suggest limited diffusion in the electrode toward the end of discharge. These results confirm that the asynchronous electrode response is not just limited to specially designed cells but occurs in fully assembled cells alike. We attribute this behavior to be a consequence of performing a local measurement over a wide-area heterogeneous reaction.

  17. Divorce and asynchronous arrival in common terns, Sterna hirundo.

    Science.gov (United States)

    GonzáLez-SolíS; Becker; Wendeln

    1999-11-01

    We investigated which of three hypotheses (better option, incompatibility or asynchronous arrival) best explains divorce in the common tern. One partner did not return the next year in 18.5% of 150 pairs. Among the 106 pairs in which both mates returned, the divorce rate was 18.9%. We found no significant differences in: breeding performance or condition in relation to the probability of divorce; quality of previous mates and new mates, mean age in relation to pair bond status; breeding success before and after divorce nor did this differ from breeding success of reunited pairs. Hence the better option and incompatibility hypotheses were not supported. However, divorce was more likely in pairs in which mates arrived asynchronously on the breeding grounds, supporting the asynchronous arrival hypothesis. Median arrival asynchrony for divorced pairs was 7.5 days and for reunited pairs 2 days; mates arriving more than 16 days apart always split up. About 20% of divorced birds lost breeding status in the year of divorce, probably as a consequence of their late arrival. Our results suggest that terns search for a new mate as soon as they arrive on the breeding grounds and that mates remain faithful to each other to avoid the costs of searching for a new partner. Thus, synchrony in arrival facilitates pair bond maintenance rather than asynchrony promoting divorce, since divorce appears to be a side-effect of asynchrony and not an active decision. Copyright 1999 The Association for the Study of Animal Behaviour. PMID:10564616

  18. Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach.

    Science.gov (United States)

    Zhu, Weiping; Chen, Weiran; Hu, Zhejie; Li, Zuoyou; Liang, Yue; Chen, Jiaojiao

    2016-01-01

    Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption. PMID:27058544

  19. Asynchronous signal-dependent non-uniform sampler

    Science.gov (United States)

    Can-Cimino, Azime; Chaparro, Luis F.; Sejdić, Ervin

    2014-05-01

    Analog sparse signals resulting from biomedical and sensing network applications are typically non-stationary with frequency-varying spectra. By ignoring that the maximum frequency of their spectra is changing, uniform sampling of sparse signals collects unnecessary samples in quiescent segments of the signal. A more appropriate sampling approach would be signal-dependent. Moreover, in many of these applications power consumption and analog processing are issues of great importance that need to be considered. In this paper we present a signal dependent non-uniform sampler that uses a Modified Asynchronous Sigma Delta Modulator which consumes low-power and can be processed using analog procedures. Using Prolate Spheroidal Wave Functions (PSWF) interpolation of the original signal is performed, thus giving an asynchronous analog to digital and digital to analog conversion. Stable solutions are obtained by using modulated PSWFs functions. The advantage of the adapted asynchronous sampler is that range of frequencies of the sparse signal is taken into account avoiding aliasing. Moreover, it requires saving only the zero-crossing times of the non-uniform samples, or their differences, and the reconstruction can be done using their quantized values and a PSWF-based interpolation. The range of frequencies analyzed can be changed and the sampler can be implemented as a bank of filters for unknown range of frequencies. The performance of the proposed algorithm is illustrated with an electroencephalogram (EEG) signal.

  20. A novel asynchronous access method with binary interfaces

    Directory of Open Access Journals (Sweden)

    Torres-Solis Jorge

    2008-10-01

    Full Text Available Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches. Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation.

  1. Non-detection of nova shells around asynchronous polars

    Science.gov (United States)

    Pagnotta, Ashley; Zurek, David

    2016-05-01

    Asynchronous polars (APs) are accreting white dwarfs (WDs) that have different WD and orbital angular velocities, unlike the rest of the known polars, which rotate synchronously (i.e. their WD and orbital angular velocities are the same). Past nova eruptions are the predicted cause of the asynchronicity, in part due to the fact that one of the APs, V1500 Cyg, was observed to undergo a nova eruption in 1975. We used the Southern African Large Telescope 10 m class telescope and the MDM 2.4 m Hiltner telescope to search for nova shells around three of the remaining four APs (V1432 Aql, BY Cam, and CD Ind) as well as one Intermediate Polar with a high asynchronicity (EX Hya). We found no evidence of nova shells in any of our images. We therefore cannot say that any of the systems besides V1500 Cyg had nova eruptions, but because not all post-nova systems have detectable shells, we also cannot exclude the possibility of a nova eruption occurring in any of these systems and knocking the rotation out of sync.

  2. THE SIX-WHEEL FRIGHT TRUCK LOCOMOTIVE OF DOUBLE DELIVERY USES RADIO-FREQUENCY TRANSFER WITH PADDING AND ASYNCHRONIZED TRACTION IMPELLENTS

    Directory of Open Access Journals (Sweden)

    M. H. Visin

    2010-10-01

    Full Text Available Our research offers a new perspective loading pattern of the 12-wheel double-feed freight electric locomotive with the asynchronous tractive motor using an adapter transformer with the high-frequency uncoupler. This will make it possible to decrease the traction-feeding transformer mass 2.3 times, to remove the current pulse advancing on the track circuit and therefore the influence on the work of the ALSE and CBS. So the railway traffic safety will be increased considerably.

  3. Impact of thermoelectric cooling modules on the efficiency of a single-phase asynchronous machine

    OpenAIRE

    Gouws, Rupert; Van Jaarsveldt, Heino

    2014-01-01

    In this paper, the authors present the impact of thermoelectric cooling modules (TECMs) on the efficiency of a single-phase asynchronous machine. TECMs are used to lower the stator winding temperature and core temperature of the single-phase asynchronous machine. A similar effect might be possible by operating the asynchronous machine in a controlled lower temperature environment or by using other means of improved controlled cooling. An overview on the materials an...

  4. Pharmacists’ Perception of Synchronous Versus Asynchronous Distance Learning for Continuing Education Programs

    OpenAIRE

    Buxton, Eric C.

    2014-01-01

    Objective. To evaluate and compare pharmacists’ satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars.

  5. Efficient IEC permanent magnet motor; Effizienter IEC Permanent-Magnetmotor (3 kW) - Jahresbericht 2007

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M.; Salathe, D.; Biner, H. P.; Evequoz, B.

    2007-07-01

    This annual report for the Swiss Federal Office of Energy (SFOE) takes a look at the work done at the Swiss Universities of Applied Sciences in Lucerne and Valais and the Circle Motor Company in 2007 on the economic feasibility, efficiency and limitations of permanent magnet motors. The higher efficiency of permanent-magnet motors in comparison with asynchronous motors for powers of over 100 kW is noted. Work done on the integration of a 3 kW permanent-magnet motor in an IEC-Standard housing is described. The construction of an efficient permanent magnet motor drive and its testing at the Valais University of Applied Sciences is discussed. The high efficiencies obtained both for the motor and its drive electronics are noted.

  6. Design and Analysis of Drive System with Slip Ring Induction Motor for Electric Traction in India

    Directory of Open Access Journals (Sweden)

    Nagamani Chandra sekara

    2015-02-01

    Full Text Available The use of Squirrel Cage for Traction has revolutionised the motive power of a Locomotive. The Asynchronous Motor is rugged with high starting Torque, has a very smooth Voltage and Speed control as compared to a DC Series Motor. When looking at the Traction perspective, a Slip Ring Induction Motor can be an alternative to the Squirrel Cage Motor as it has higher starting Torque and better efficiency than a Squirrel Cage Motor. the Slip Power Recovery scheme also plays a proactive role as ther can be substantial savings of energy in case of a Slip Ring Induction Motor. A detailed design and analysis of a Drive System with Slip Ring Induction Motor for Electric Traction is presented in this Research Paper

  7. Contrôle d'une machine asynchrone par estimation robuste de la vitesse

    Science.gov (United States)

    Roboam, X.; Hapiot, J. C.; de Fornel, B.; Andrieux, C.

    1992-03-01

    This paper describes the study and the implementation of a variable speed drive for induction motor with no mechanical sensor. Power is supplied by a current-controlled voltage-source inverter. The lack of information (only two line-current sensors) requires an accurate and reliable reconstitution of the main quantities not sensed (flux, speed, torque). The results obtained show the excellent quality of the estimated speed, whatever the operating condition and despite the perturbations applied to the system. This study finally leads to the construction of a prototype. Cet article décrit l'étude et la mise en oeuvre d'un variateur de vitesse pour machine asynchrone sans capteur mécanique et alimentée par un onduleur de tension cotrôlé en courant. Le manque d'information (2 capteurs de courants de ligne uniquement) nécessite la reconstitution fiable et précise des grandeurs fondamentales non mesurées (flux, vitesse, couple). Les résultats obtenus montrent notamment l'excellente qualité de l'estimation de vitesse, quel que soit le point de fonctionnement et en dépit des perturbations auxquelles le système est soumis. Cette étude donne lieu à la réalisation d'un variateur prototype.

  8. Motor homopolar

    OpenAIRE

    2007-01-01

    Mostramos la construcción de un modelo de motor homopolar, uno de los más antiguos tipos de motores eléctricos. Se caracterizan porque el campo magnético del imán mantiene siempre la misma polaridad (de ahí su nombre, del griego homos, igual), de modo que, cuando una corriente eléctrica atraviesa el campo magnético, aparece una fuerza que hace girar los elementos no fijados mecánicamente. En el sencillísimo motor homopolar colgado (Schlichting y Ucke 2004), el imán puede girar ...

  9. Application of stepping motor

    International Nuclear Information System (INIS)

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  10. Arithmetic Operations and Factorization using Asynchronous P Systems

    Directory of Open Access Journals (Sweden)

    Takayuki Murakawa

    2012-07-01

    Full Text Available

    In the present paper, we consider the asynchronous parallelism in membrane computing, and propose asynchronous P systems that perform two basic arithmetic operations and factorization. Since there is no restrictive assumption for application of rules, sequential and maximal parallel executions are allowed on the asynchronous P system.

    We first propose a P system that computes addition of two binary numbers of m bits.  The P system works in O(m sequential and parallel steps using O(m types of objects. We next propose a P system for multiplication of the two binary numbers of m bits, and show that the P system works in O(m log m parallel steps or O(m3 sequential steps using O(m2 types of objects. Finally, we propose a P system for factorization of a positive integer of $m$ bits using the above P system as a sub-system. The P system computes the factorization in O(m log m parallel steps or O(4m 

  11. Wind Generator Stabilization with Doubly-Fed Asynchronous Machine

    Institute of Scientific and Technical Information of China (English)

    WU Li; WANG Zhi-xin

    2007-01-01

    This paper investigates the function of doubly-fed asynchronous machine(DASM) with emphasis placed on its ability to the stabilization of the power system including wind generators. P(active power) and Q(reactive power) compensation from DASM can be regulated independently through secondary-excitation controlling. Simulation results by power system computer aided design(PSCAD) show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures. Comparison studies have also been performed between wind turbine pitch control and proposed method.

  12. Entry of Ebola Virus is an Asynchronous Process.

    Science.gov (United States)

    Reynard, Olivier; Volchkov, Viktor E

    2015-10-01

    Ebola virus (EBOV) is responsible for a severe fever with a high mortality rate. The diverse nature of the attachment of the virus to the cell surface, the initial step of virus entry, raises questions concerning the kinetics of the virus internalization process. We investigated EBOV entry kinetics using the activity of a particular monoclonal antibody that neutralizes virus infectivity. We demonstrate that inoculation of cells with EBOV results in an asynchronous entry process, as revealed by the ability of the virus to remain in a cell-bound state for an extended period of time before it is internalized. PMID:25941332

  13. Hyperplastic polyposis associated with two asynchronous colon cancers

    Institute of Scientific and Technical Information of China (English)

    Masaya Kurobe; Kuniko Abe; Naoe Kinoshita; Masanobu Anami; Hirotaka Tokai; Yoshinori Ryu; Chun Yang Wen; Takashi Kanematsu; Tomayoshi Hayashi

    2007-01-01

    We report a patient with hyperplastic polyposis who had two asynchronous colon cancers, a combined adenoma-hyperplastic polyp, a serrated adenoma, and tubular adenomas. Hyperplastic polyposis is thought to be a precancerous lesion; and adenocarcinoma arises from hyperplastic polyposis through the hyperplastic polyp-adenoma-carcinoma sequence. Most polyps in patients with hyperplastic polyposis present as blandlooking hyperplastic polyps, which are regarded as nonneoplastic lesions; however, the risk of malignancy should not be underestimated. In patients with multiple hyperplastic polyps, hyperplastic polyposis should be identified and followed up carefully in order to detect malignant transformation in the early stage.

  14. Positive Semidefinite Integrated Covariance Estimation, Factorizations and Asynchronicity

    DEFF Research Database (Denmark)

    Boudt, Kris; Laurent, Sébastien; Lunde, Asger;

    observations as possible. The estimator is guaranteed positive semidefinite. Monte Carlo simulations confirm good finite sample properties. In the application we forecast portfolio Value-at-Risk and sector risk exposures for a portfolio of 52 stocks. We find that forecasts obtained from dynamic models......An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization on the correlation matrix in order to exploit the heterogeneity in trading intensity to estimate the different parameters sequentially with as many...... utilizing the proposed high-frequency estimator provide statistically and economically superior forecasts to models using daily returns....

  15. The Key Implementation Technology of Client/Server's Asynchronous Communication Programs

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper introduces the implementation method,key technology and flowchart of Client/Server's asynchronous communication programs on Linux or Unix,and further explains a few problems to which should pay attention for improving CPU's efficiency in implementing asynchronous communication programs.

  16. Designing Asynchronous Online Discussion Environments: Recent Progress and Possible Future Directions

    Science.gov (United States)

    Gao, Fei; Zhang, Tianyi; Franklin, Teresa

    2013-01-01

    Asynchronous online discussion environments are important platforms to support learning. Research suggests, however, threaded forums, one of the most popular asynchronous discussion environments, do not often foster productive online discussions naturally. This paper explores how certain properties of threaded forums have affected or constrained…

  17. Anonymity and Motivation in Asynchronous Discussions and L2 Vocabulary Learning

    Science.gov (United States)

    Polat, Nihat; Mancilla, Rae; Mahalingappa, Laura

    2013-01-01

    This study investigates L2 attainment in asynchronous online environments, specifically possible relationships among anonymity, L2 motivation, participation in discussions, quality of L2 production, and success in L2 vocabulary learning. It examines, in asynchronous discussions, (a) if participation and (b) motivation contribute to L2 vocabulary…

  18. Using Television Sitcoms to Facilitate Asynchronous Discussions in the Online Communication Course

    Science.gov (United States)

    Tolman, Elizabeth; Asbury, Bryan

    2012-01-01

    Asynchronous discussions are a useful instructional resource in the online communication course. In discussion groups students have the opportunity to actively participate and interact with students and the instructor. Asynchronous communication allows for flexibility because "participants can interact with significant amounts of time between…

  19. The Role of Offline Metalanguage Talk in Asynchronous Computer-Mediated Communication

    Science.gov (United States)

    Kitade, Keiko

    2008-01-01

    In order to demonstrate how learners utilize the text-based asynchronous attributes of the Bulletin Board System, this study explored Japanese-as-a-second-language learners' metalanguage episodes (Swain & Lapkin, 1995, 1998) in offline verbal peer speech and online asynchronous discussions with their Japanese key pals. The findings suggest the…

  20. Grain Refining of Flange Plate for Welded H Section Steel Made under Asynchronous Rolling Condition

    Institute of Scientific and Technical Information of China (English)

    DAI Hui; SUN Jiquan; TANG Di

    2011-01-01

    Asynchronous rolling technology was adopted for the accumulated ten passes cold rolling,flange plate steel,and for welded H section steel,respectively.The metallographic microstructure analysis,tensile test and annealing test were carried out for cold rolled pieces; thus the ratio of length to width of grain,tensile strength,relationship between the grain size and asynchronous rolling process parameters after annealing can be obtained.The experimental results show that the relationship between the asynchronous rolling and the shearing deformation of rolled pieces can make a reasonable interpretation of the mechanism that asynchronous rolling may improve the strain accumulated energy of rolled pieces and the strength of flange plate steel.This paper provides a theoretical basis for the application of asynchronous rolling in improving the strength of flange plate steel.

  1. Cooperative and asynchronous stereo vision for dynamic vision sensors

    International Nuclear Information System (INIS)

    Dynamic vision sensors (DVSs) encode visual input as a stream of events generated upon relative light intensity changes in the scene. These sensors have the advantage of allowing simultaneously high temporal resolution (better than 10 µs) and wide dynamic range (>120 dB) at sparse data representation, which is not possible with clocked vision sensors. In this paper, we focus on the task of stereo reconstruction. The spatiotemporal and asynchronous aspects of data provided by the sensor impose a different stereo reconstruction approach from the one applied for synchronous frame-based cameras. We propose to model the event-driven stereo matching by a cooperative network (Marr and Poggio 1976 Science 194 283–7). The history of the recent activity in the scene is stored in the network, which serves as spatiotemporal context used in disparity calculation for each incoming event. The network constantly evolves in time, as events are generated. In our work, not only the spatiotemporal aspect of the data is preserved but also the matching is performed asynchronously. The results of the experiments prove that the proposed approach is well adapted for DVS data and can be successfully used for disparity calculation. (paper)

  2. Asynchronous compressed beamformer for portable diagnostic ultrasound systems.

    Science.gov (United States)

    Zhou, Jun; Hoyos, Sebastian; Sadler, Brian

    2014-11-01

    State-of-the-art portable ultrasound imaging systems employ a small transducer array and a low carrier frequency to fit stringent constraints on power and form factor, and this tends to compromise the ultrasound imaging quality. In this paper, we present a low-complexity low-power asynchronous compressed beamformer (ACB) for portable diagnostic ultrasound. The proposed ACB integrates asynchronous sampling and compressive sensing (CS), and is capable of reducing data conversion power and handling a large data volume at the mixed-signal interface. A high-rate continuoustime ternary encoding (CT-TE) scheme eliminates the need for interpolation filters and coordinate rotation digital computer (CORDIC) units typically used in a conventional architecture. A split-projection least squares (SPLS) signal reconstruction algorithm is applied that replaces high-cost nonlinear signal recovery with a series of low-complexity and independent linear problems. Experiments with measured ultrasound data demonstrate the proposed ACB architecture, and the SPLS reconstruction algorithm achieves 9-fold data compression compared with Nyquist sampling. PMID:25389158

  3. Experience with synchronous and asynchronous digital control systems

    Science.gov (United States)

    Regenie, V. A.; Chacon, C. V.; Lock, W. P.

    1986-01-01

    Flight control systems have undergone a revolution since the days of simple mechanical linkages; presently the most advanced systems are full-authority, full-time digital systems controlling unstable aircraft. With the use of advanced control systems, the aerodynamic design can incorporate features that allow greater performance and fuel savings, as can be seen on the new Airbus design and advanced tactical fighter concepts. These advanced aircraft will be and are relying on the flight control system to provide the stability and handling qualities required for safe flight and to allow the pilot to control the aircraft. Various design philosophies have been proposed and followed to investigate system architectures for these advanced flight control systems. One major area of discussion is whether a multichannel digital control system should be synchronous or asynchronous. This paper addressed the flight experience at the Dryden Flight Research Facility of NASA's Ames Research Center with both synchronous and asynchronous digital flight control systems. Four different flight control systems are evaluated against criteria such as software reliability, cost increases, and schedule delays.

  4. Asynchronous replica exchange software for grid and heterogeneous computing

    Science.gov (United States)

    Gallicchio, Emilio; Xia, Junchao; Flynn, William F.; Zhang, Baofeng; Samlalsingh, Sade; Mentes, Ahmet; Levy, Ronald M.

    2015-11-01

    Parallel replica exchange sampling is an extended ensemble technique often used to accelerate the exploration of the conformational ensemble of atomistic molecular simulations of chemical systems. Inter-process communication and coordination requirements have historically discouraged the deployment of replica exchange on distributed and heterogeneous resources. Here we describe the architecture of a software (named ASyncRE) for performing asynchronous replica exchange molecular simulations on volunteered computing grids and heterogeneous high performance clusters. The asynchronous replica exchange algorithm on which the software is based avoids centralized synchronization steps and the need for direct communication between remote processes. It allows molecular dynamics threads to progress at different rates and enables parameter exchanges among arbitrary sets of replicas independently from other replicas. ASyncRE is written in Python following a modular design conducive to extensions to various replica exchange schemes and molecular dynamics engines. Applications of the software for the modeling of association equilibria of supramolecular and macromolecular complexes on BOINC campus computational grids and on the CPU/MIC heterogeneous hardware of the XSEDE Stampede supercomputer are illustrated. They show the ability of ASyncRE to utilize large grids of desktop computers running the Windows, MacOS, and/or Linux operating systems as well as collections of high performance heterogeneous hardware devices.

  5. A Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw

    2005-01-01

    A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary optimization of a typical transport aircraft wing as an example.

  6. Asynchronous Transfer Mode Quality-of-Service Testing

    Science.gov (United States)

    Ivancic, William D.

    1998-01-01

    In support of satellite-ATM interoperability, researchers at the NASA Lewis Research Center performed asynchronous transfer mode (ATM) quality-of-service experiments using MPEG-2 (ATM application layer 5, AAL5) over ATM over an emulated satellite link. The purpose of these experiments was to determine the free-space link quality necessary to use the ATM protocol to transmit high-quality multimedia information. The experimental results have been submitted to various International Telecommunications Union (ITU) study groups in order to improve and modify current standards and recommendations for the telecommunications industry. Quality-of-service parameters for Class I, stringent class requirements for ITU-T I.356 are currently being debated. The experimental results presented will help to establish these quality-of-service thresholds. This material will also be useful in the development of the ITU-R WP-4B's Draft Preliminary New Recommendation on the Transmission of Asynchronous Transfer Mode Traffic via Satellite (Rec. S.atm).

  7. Spatiotemporal Features for Asynchronous Event-based Data

    Directory of Open Access Journals (Sweden)

    Xavier eLagorce

    2015-02-01

    Full Text Available Bio-inspired asynchronous event-based vision sensors are currently introducing a paradigm shift in visual information processing. These new sensors rely on a stimulus-driven principle of light acquisition similar to biological retinas. They are event-driven and fully asynchronous, thereby reducing redundancy and encoding exact times of input signal changes, leading to a very precise temporal resolution. Approaches for higher-level computer vision often rely on the realiable detection of features in visual frames, but similar definitions of features for the novel dynamic and event-based visual input representation of silicon retinas have so far been lacking. This article addresses the problem of learning and recognizing features for event-based vision sensors, which capture properties of truly spatiotemporal volumes of sparse visual event information. A novel computational architecture for learning and encoding spatiotemporal features is introduced based on a set of predictive recurrent reservoir networks, competing via winner-take-all selection. Features are learned in an unsupervised manner from real-world input recorded with event-based vision sensors. It is shown that the networks in the architecture learn distinct and task-specific dynamic visual features, and can predict their trajectories over time.

  8. Design and test of asynchronous eSFQ circuits

    International Nuclear Information System (INIS)

    We designed and tested new energy-efficient single flux quantum (eSFQ) circuits. The eSFQ design approach is based on biasing logic gates via decision-making pairs (DMPs) which connect clock lines to synchronous gates. The eSFQ design of asynchronous gates is more challenging, since these gates are not clocked. We demonstrate eSFQ designs of asynchronous circuits and implemented two versions of eSFQ toggle flip-flops (eTFF) cells embedded in a synchronous shift register environment. The first design is based on the bias-free version of a TFF operating in the ballistic mode. In the second design, the TFFs dc bias is applied symmetrically, while the necessary half-quantum phase skew is achieved by magnetic flux bias, which can also be done with a pi-junction phase shifter. Surrounding shift registers are the eSFQ versions of the RSFQ shift register with two junctions per bit. In this work, we report the functional operation of these eSFQ circuits and their energy consumption. (paper)

  9. An Examination of Asynchronous Communication Experiences and Perspectives of Students in an Online Course: A Case Study.

    Science.gov (United States)

    Vonderwell, Selma

    2003-01-01

    Explores asynchronous communication perspectives and experiences of undergraduate students in an online course. Interviews with 22 preservice teachers, student-to-instructor email transcripts, asynchronous discussion transcripts, and two independent reviewers' reviews of the asynchronous discussions were used to collect and analyze the data.…

  10. Economic viability, applications and limits of efficient permanent magnet motors - Summary and update; Wirtschaftlichkeit, Anwendungen und Grenzen von effizienten Permanent-Magnet-Motoren - Zusammenfassung und Update - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M. [Circle Motor AG, Guemligen (Switzerland); Biner, H.-P.; Evequoz, B. [Hochschule Westschweiz, Delemont (Switzerland); Salathe, D. [Hochschule Luzern Technik und Architektur, Horw (Switzerland)

    2009-06-15

    This final report for the Swiss Federal Office of Energy (SFOE), takes a look at the economic viability, applications and limits of efficient permanent magnet motors. Permanent magnet motors are compared with standard IEC asynchronous motors. In a theoretical part of the report, it is discussed how the increasing size of the motor influences efficiency, weight, volume and power. The results of practical tests carried out on six motors are presented. Three standard motors with varying efficiency were compared with three permanent-magnet motors for the power range around 3 kW. Market-oriented considerations concerning permanent-magnet motors are discussed. Operational criteria for the choice of the type of motor to be used are also examined.

  11. Motor Magnates

    Institute of Scientific and Technical Information of China (English)

    ISABEL DING

    2008-01-01

    @@ The automotive industry is often seen as a man's world. Wang Fengying (王风英) begs to differ. The 38-year-old has presided over Great Wall Motors (长城汽车), the leading pick-up truck and Sport Utility Vehicle(SUV) manufacturer in China for the past five years.

  12. THE MOTOR

    DEFF Research Database (Denmark)

    Gammelgaard Nielsen, Anders

    2011-01-01

    MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...

  13. Motor radiculopathy

    OpenAIRE

    Khan, Afsha; Camilleri, Jeremy

    2012-01-01

    A 48-year-old immunosuppressed woman presented to a rheumatology follow-up clinic after suffering from herpes zoster infection. She had manifestations of foot drop 3 months after the initial infection. She was diagnosed with motor radiculopathy following herpes zoster infection that was effectively managed by physiotherapy and amitriptyline.

  14. Label-acquired magnetorotation for biosensing: An asynchronous rotation assay

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Ariel, E-mail: hecht@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); Kinnunen, Paivo, E-mail: pkkinn@umich.ed [University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); McNaughton, Brandon, E-mail: bmcnaugh@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States); Kopelman, Raoul, E-mail: kopelman@umich.ed [University of Michigan, Department of Biomedical Engineering, 2200 Bonisteel, Ann Arbor, MI 48109-2099 (United States); University of Michigan, Department of Chemistry, 930 North University, Ann Arbor, MI 48109-1055 (United States); University of Michigan, Applied Physics Program, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120 (United States)

    2011-02-15

    This paper presents a novel application of magnetic particles for biosensing, called label-acquired magnetorotation (LAM). This method is based on a combination of the traditional sandwich assay format with the asynchronous magnetic bead rotation (AMBR) method. In label-acquired magnetorotation, an analyte facilitates the binding of a magnetic label bead to a nonmagnetic solid phase sphere, forming a sandwich complex. The sandwich complex is then placed in a rotating magnetic field, where the rotational frequency of the sandwich complex is a function of the amount of analyte attached to the surface of the sphere. Here, we use streptavidin-coated beads and biotin-coated particles as analyte mimics, to be replaced by proteins and other biological targets in future work. We show this sensing method to have a dynamic range of two orders of magnitude.

  15. Normalized and Asynchronous Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; Balbo, M; Bergmann, M; Biland, A; Blank, M; Bretz, T; Bruegge, K A; Buss, J; Domke, M; Dorner, D; Einecke, S; Hempfling, C; Hildebrand, D; Hughes, G; Lustermann, W; Mannheim, K; Mueller, S A; Neise, D; Neronov, A; Noethe, M; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Shukla, A; Temme, F; Thaele, J; Toscano, S; Vogler, P; Walter, R; Wilbert, A

    2016-01-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it ca...

  16. Numerical Simulation of Asynchronous Simulated Moving Bed Chromatography

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    Asynchronous simulated moving bed chromatography (ASMBC), known also as the "VARICOL" process, is more efficient and flexible than the well-known and traditional simulated moving bed chromatography (SMBC). A detailed model of ASMBC, taking account of non-linear competitive isotherms, mass transfer parameters, and complex port switching schedule parameters, was developed to simulate the complex dynamics of ASMBC.The simulated performance is in close agreement with the experimental data of chiral separation reported in the literature. The simulation results show that ASMBC can achieve the performance similar to SMBC with fewer columns and can achieve better performance than SMBC with the same total column number. All design and operation parameters can be chosen correctly by numerical simulation. This detailed ASMBC model and the numerical technique are useful for design, operation, optimization and scale-up of ASMBC.

  17. Blow Flies Visiting Decaying Alligators: Is Succession Synchronous or Asynchronous?

    Directory of Open Access Journals (Sweden)

    Mark P. Nelder

    2009-01-01

    Full Text Available Succession patterns of adult blow flies (Diptera: Calliphoridae on decaying alligators were investigated in Mobile (Ala, USA during August 2002. The most abundant blow fly species visiting the carcasses were Chrysomya rufifacies (Macquart, Cochliomyia macellaria (Fabricus, Chrysomya megacephala (Fabricus, Phormia regina (Meigen, and Lucilia coeruleiviridis (Macquart. Lucilia coeruleiviridis was collected more often during the early stages of decomposition, followed by Chrysomya spp., Cochliomyia macellaria, and Phormia regina in the later stages. Lucilia coeruleiviridis was the only synchronous blow fly on the three carcasses; other blow fly species exhibited only site-specific synchrony. Using dichotomous correlations and analyses of variance, we demonstrated that blow fly-community succession was asynchronous among three alligators; however, Monte Carlo simulations indicate that there was some degree of synchrony between the carcasses.

  18. Operational aspects of asynchronous filtering for hydrological forecasting

    Directory of Open Access Journals (Sweden)

    O. Rakovec

    2015-03-01

    Full Text Available This study investigates the suitability of the Asynchronous Ensemble Kalman Filter (AEnKF and a partitioned updating scheme for hydrological forecasting. The AEnKF requires forward integration of the model for the analysis and enables assimilation of current and past observations simultaneously at a single analysis step. The results of discharge assimilation into a grid-based hydrological model for the Upper Ourthe catchment in the Belgian Ardennes show that including past predictions and observations in the data assimilation method improves the model forecasts. Additionally, we show that elimination of the strongly non-linear relation between the soil moisture storage and assimilated discharge observations from the model update becomes beneficial for improved operational forecasting, which is evaluated using several validation measures.

  19. LOAD CONTROL OF A 3-Ø SELF- EXCITED ASYNCHRONOUS GENERATOR

    Directory of Open Access Journals (Sweden)

    SUBRAMANIAN KULANDHAIVELU

    2011-02-01

    Full Text Available This paper describes the simulation based performance study of a 3-Ø self-excited asynchronous generator (SEASG in constant power operation. A feed back voltage based controller by using a load control technique to control and retain the generator terminal voltage constant. This technique mostly used in uncontrolled hydroturbine driven induction generators in a stand-alone power generator. The results has been validate by the steady state equivalent circuit analysis of a 2.2kW, 415Volts, 4.7A, Star connected, 1440-rpm induction generator. The proposed study system has been simulated using Mat lab/Simulink version-7.0.The simulated results arepresented.

  20. The Efficacy of Deliberate Practice Delivered Using Asynchronous Training Technology

    Directory of Open Access Journals (Sweden)

    Colleen E. McEdwards

    2014-04-01

    Full Text Available Employee productivity is key to survival in business. Senior employees require access to advanced training that does not necessitate extended periods away from their work. Once performance begins to plateau, it can be difficult to reach experienced employees with cost-effective, timely, and relevant training opportunities. Organizations must find ways to enhance employee performance; however, research suggests workplace training is too expensive and is too often without lasting benefit. The purpose of this study is to further quantify deliberate practice as a potentially efficient, customizable mode of training using asynchronous e-learning. The study compared traditional seminars with online deliberate practice training. While additional research is needed in wider learning contexts and with larger sample sizes, improvements among the deliberate practice groups were significant. Using a mixed methods pretest/posttest research design, the deliberate practice training showed improved performance and increased satisfaction compared with the traditional seminar approach.

  1. Commande vectorielle d'un moteur asynchrone sans capteur

    OpenAIRE

    Ourth, T.

    1993-01-01

    Ce papier présente la commande par flux orienté d'une machine asynchrone sans capteur de vitesse ou de position. Le flux rotorique est évalué grâce à un observateur d'ordre réduit d'un type voisin de Luenberger travaillant dans un repère fixe statorique. L'estimation de la vitesse est obtenue à partir du module du flux rotorique, des courants statoriques mesurés et de l'angle d'orientation du flux rotorique. Cette étude basée sur des simulations démontre un comportement acceptable de la comma...

  2. Multi-rate asynchronous sampling of bandwidth-limited signals

    CERN Document Server

    Feldster, Alfred; Horowitz, Moshe; Rosenthal, Amir; Zach, Shlomo; Singer, Lea

    2008-01-01

    We demonstrate experimentally an optical system for under-sampling several bandwidth limited signals with carrier frequencies that are not known apriori that can be located anywhere within a very broad frequency region between 0-18 GHz. The system is based on under-sampling asynchronously at three different sampling rates. The pulses required for the under-sampling are generated by a combination of an electrical comb generator and an electro-absorption modulator. To reduce loss and improve performance the implementation of the optical system is based on a wavelength division multiplexing technique. An accurate reconstruction of both the phase and the amplitude of the signals was obtained when two chirped signals generated simultaneously were sampled.

  3. The Formation of the Wide Asynchronous Binary Asteroid Population

    CERN Document Server

    Jacobson, Seth A; McMahon, Jay

    2013-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth and Main Belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, planetary flybys and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (i) these systems are formed from rotational fission, (ii) their satellites are tidally locked, (iii) their orbits are expanded by the BYORP effect, (iv) their satellites de-synchronize due to the adiabatic invariance between the libration of the secondary and the mutual orbit, and (v) the secondary avoids resynchronization due to the the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torq...

  4. Minor Planet 1016 Anitra: A Likely Asynchronous Binary

    Science.gov (United States)

    Pilcher, Frederick; Benishek, Vladimir; Jacobsen, Jens; Kristensen, Leif Hugo; Lang, Kim; Larsen, Frank R.; Odden, Caroline; Pravec, Petr

    2016-07-01

    Analysis of photometry data for 1016 Anitra using a single period analysis shows a lightcurve with a period of 5.9296 hours and amplitude of 0.30 mag, with short period fluctuations. A simultaneous two-period analysis of the data found two smooth bimodal lightcurves with periods and amplitudes of P1 = 5.92951 h, A1 = 0.30 mag and P2 = 2.609143 h, A2 = 0.10 mag. These results are interpreted as the rotation of the two components of an asynchronous binary system. Four additional attenuations were observed that may have been caused by satellite mutual events, but those data were insufficient to yield an orbital period.

  5. Asynchronous Variational Integration of Interaction Potentials for Contact Mechanics

    CERN Document Server

    Vouga, Etienne; Tamstorf, Rasmus; Grinspun, Eitan

    2009-01-01

    Asynchronous Variational Integrators (AVIs) have demonstrated long-time good energy behavior. It was previously conjectured that this remarkable property is due to their geometric nature: they preserve a discrete multisymplectic form. Previous proofs of AVIs' multisymplecticity assume that the potentials are of an elastic type, i.e., specified by volume integration over the material domain, an assumption violated by interaction-type potentials, such as penalty forces used to model mechanical contact. We extend the proof of AVI multisymplecticity, showing that AVIs remain multisymplectic under relaxed assumptions on the type of potential. The extended theory thus accommodates the simulation of mechanical contact in elastica (such as thin shells) and multibody systems (such as granular materials) with no drift of conserved quantities (energy, momentum) over long run times, using the algorithms in [3]. We present data from a numerical experiment measuring the long time energy behavior of simulated contact, compa...

  6. Asynchronous data-driven classification of weapon systems

    International Nuclear Information System (INIS)

    This communication addresses real-time weapon classification by analysis of asynchronous acoustic data, collected from microphones on a sensor network. The weapon classification algorithm consists of two parts: (i) feature extraction from time-series data using symbolic dynamic filtering (SDF), and (ii) pattern classification based on the extracted features using the language measure (LM) and support vector machine (SVM). The proposed algorithm has been tested on field data, generated by firing of two types of rifles. The results of analysis demonstrate high accuracy and fast execution of the pattern classification algorithm with low memory requirements. Potential applications include simultaneous shooter localization and weapon classification with soldier-wearable networked sensors. (rapid communication)

  7. Asynchronous learning: student utilization out of sync with their preference

    Directory of Open Access Journals (Sweden)

    Edward K. Lew

    2016-06-01

    Full Text Available Background: Asynchronous learning is gaining popularity. Data are limited regarding this learning method in medical students rotating in emergency medicine (EM. In EM, faculty time is limited to give in-person lectures. The authors sought to create an online curriculum that students could utilize as an additional learning modality. Objective: The goal was to evaluate effectiveness, participation, and preference for this mode of learning. Methods: We developed five online, narrated PowerPoint presentations. After orientation, access to the online curriculum was provided to the students, which they could review at their leisure. Results: One hundred and seven fourth-year medical students participated. They reported the curriculum to be of high quality. Pretest scores were similar for those that viewed all lectures – compliant group (CG (9.5 [CI 4.8–14.1] and those that did not view any – non-compliant group (NCG (9.6 [CI 5.9–13.4]. There was no statistical significant difference in posttest scores between the groups although there was improvement overall: CG 14.6 (CI 6.9–22.1; NCG 11.4 (CI 5.7–17.1. A majority (69.2% favored inclusion of asynchronous learning, but less than a quarter (22.4% reported viewing all five modules and more than a third (36.4% viewed none. Conclusion: Despite student-expressed preference for an online curriculum, they used the online resource less than expected. This should give pause to educators looking to convert core EM topics to an online format. However, when high-quality online lectures are utilized as a learning tool, this study demonstrates that they had neither a positive nor a negative impact on test scores.

  8. UNIVERSAL REGULAR AUTONOMOUS ASYNCHRONOUS SYSTEMS: ω-LIMIT SETS, INVARIANCE AND BASINS OF ATTRACTION

    Directory of Open Access Journals (Sweden)

    Serban Vlad

    2011-07-01

    Full Text Available The asynchronous systems are the non-deterministic real timebinarymodels of the asynchronous circuits from electrical engineering.Autonomy means that the circuits and their models have no input.Regularity means analogies with the dynamical systems, thus such systems may be considered to be real time dynamical systems with a’vector field’, Universality refers to the case when the state space of the system is the greatest possible in the sense of theinclusion. The purpose of this paper is that of defining, by analogy with the dynamical systems theory, the omega-limit sets, the invariance and the basins of attraction of the universal regular autonomous asynchronous systems.

  9. Argo: A Time-Elastic Time-Division-Multiplexed NOC using Asynchronous Routers

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens

    In this paper we explore the use of asynchronous routers in a time-division-multiplexed (TDM) network-on-chip (NOC), Argo, that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs are...... either synchronous or mesochronous. We use asynchronous routers to achieve a simpler, smaller, and more robust, self-timed design. Our design exploits the fact that pipelined asynchronous circuits also behave as ripple FIFOs. Thus, it avoids the need for explicit synchronization FIFOs between the routers...

  10. Advanced Motors

    Energy Technology Data Exchange (ETDEWEB)

    Knoth, Edward A.; Chelluri, Bhanumathi; Schumaker, Edward J.

    2012-12-14

    Project Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, “Motors and Generators for the 21st Century”. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to

  11. A DC brushless PM motor driven photovoltaic water pumping system

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shijie; Xie, Lei; He, Huiruo; Zhang, Hualin; Zhou, Longhua; Liu, Wen [Sun Yat-sen Univ., Zhuhai (China). Inst. of Power Electronics and Control Technology

    2008-07-01

    Along with the worldwide more attention to environment and rapid development of photovoltaic industry, the PV water pumping system has rapidly developed, the economic advantage of which brings it into prominence. It was estimated, up to now the operating PV water pumping systems in the world may exceed hundreds thousand sets and with a driving increasing tendency. In many cases the distributed stations gain the advantages over PV feed-in grid-connected pump. The majority of the PV pumping systems are driven by an ac asynchronous motor, which are generally of lower efficiency, especially for small-scale systems. A dc permanent magnetic, brushless, sensorless and casting resin motor are developed and used in PV water pumping systems, the experiments and operations of 19 demonstrative stations in Guangdong show that the results on economics and reliability are excited. It can save even 15% {proportional_to} 20% PV modules in comparison with an asynchronous motor driven under same sunshine, water head and flow. An example of comparison between systems with batteries and without batteries is also given in this paper. Finally the commercialization, marketing and subsidy policies of PV water pumping system in China are discussed. (orig.)

  12. New Method for Accurate Parameter Estimation of Induction Motors Based on Artificial Bee Colony Algorithm

    OpenAIRE

    Jamadi, Mohammad; Merrikh-Bayat, Farshad

    2014-01-01

    This paper proposes an effective method for estimating the parameters of double-cage induction motors by using Artificial Bee Colony (ABC) algorithm. For this purpose the unknown parameters in the electrical model of asynchronous machine are calculated such that the sum of the square of differences between full load torques, starting torques, maximum torques, starting currents, full load currents, and nominal power factors obtained from model and provided by manufacturer is minimized. In orde...

  13. Analysis of the three-phase induction motor with spiral sheet rotor

    OpenAIRE

    Mujal Rosas, Ramón María

    2012-01-01

    The improvements obtained on the torque with low currents using rotor with spiral sheets are analyzed in this paper. To have a complete study, several rotors and stators have been built to verify the electromagnetic variations on the three-phase asynchronous motors where they combine different constructive and mechanical characteristics of the related elements: changing inertias, constructive materials, and the geometrical shapes and disposition of the sheets. These different type...

  14. Three Level Diode Clamped Inverter Fed Induction Motor with Dtc-Svm

    OpenAIRE

    V. Ranjith Kumar

    2013-01-01

    This project presents a three-level diode-clamped inverter feeding an asynchronous motor drive with direct torque control (DTC). The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a diode-clamped inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel c...

  15. Novel rotating characteristics of a squirrel-cage-type HTS induction/synchronous motor

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, T; Ogama, Y; Miyake, H; Nagao, K; Nishimura, T [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura 1, Nishikyo-Ku, Kyoto 615-8510 (Japan)

    2007-10-15

    This paper describes the rotating characteristics of a high-T{sub c} superconducting induction/synchronous motor, which possesses both asynchronous and synchronous torques even though its structure is exactly the same as the squirrel-cage-type induction motor. Two kinds of Bi-2223/Ag multifilamentary tapes were utilized for the secondary windings. A commercialized motor (1.5 kW) was subjected to this study. A conventional (normal conducting) stator (three-phase, four-pole) was directly utilized, and only the squirrel-cage windings were replaced with the superconducting tapes. The tests were performed after the fabricated motor was immersed in liquid nitrogen. The operating temperature was also varied by pumping out the liquid nitrogen. It is shown that the motor is successfully synchronized for the temperature range from 65 to 77 K. Detailed discussions for such novel rotating characteristics are reported based on the electrical equivalent circuit.

  16. Novel rotating characteristics of a squirrel-cage-type HTS induction/synchronous motor

    International Nuclear Information System (INIS)

    This paper describes the rotating characteristics of a high-Tc superconducting induction/synchronous motor, which possesses both asynchronous and synchronous torques even though its structure is exactly the same as the squirrel-cage-type induction motor. Two kinds of Bi-2223/Ag multifilamentary tapes were utilized for the secondary windings. A commercialized motor (1.5 kW) was subjected to this study. A conventional (normal conducting) stator (three-phase, four-pole) was directly utilized, and only the squirrel-cage windings were replaced with the superconducting tapes. The tests were performed after the fabricated motor was immersed in liquid nitrogen. The operating temperature was also varied by pumping out the liquid nitrogen. It is shown that the motor is successfully synchronized for the temperature range from 65 to 77 K. Detailed discussions for such novel rotating characteristics are reported based on the electrical equivalent circuit

  17. Modeling and Implementation for Embedded DC Motor Ethernet Control System

    OpenAIRE

    Zhu, Lingbo; Dai, Guanzhong; Shi, Li; Lin-Shi, Xuefang; Rétif, Jean-Marie

    2008-01-01

    In this paper, a model of Embedded DC Motor Ethernet Control System is proposed with analysis on transmission time delay and data packet dropout. Based on this model, the ECS is described as a two-state asynchronous dynamical system with output feedback control and then implemented on a platform which uses a PC as a central controller and an ARM9 kit as a remote controller. As a key part of developments, embedded programs including client program and Linux Module are realized on the kit. The ...

  18. Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

    DEFF Research Database (Denmark)

    Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.;

    2016-01-01

    We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

  19. Asynchronous abdomino-parasacral resection of a giant pelvic lipoma protruding to the left buttock

    Directory of Open Access Journals (Sweden)

    Masanori Sato

    2014-01-01

    CONCLUSION: The asynchronous abdomino-parasacral approach with several turnings of the patient's body and plastic bag packing of the tumor were advantageous to manage en bloc resection of the giant pelvic lipoma presented in this case study.

  20. Asynchronous Sensor fuSion for Improved Safety of air Traffic (ASSIST) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI proposes to develop, implement and test a collision detection system for unmanned aerial vehicles (UAV), referred to as the Asynchronous Sensor fuSion for...

  1. Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

    OpenAIRE

    Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

    2008-01-01

    Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

  2. Low-power Implementation of an Encryption/Decryption System with Asynchronous Techniques

    Directory of Open Access Journals (Sweden)

    Nikos Sklavos

    2002-01-01

    Full Text Available An asynchronous VLSI implementation of the International Data Encryption Algorithm (IDEA is presented in this paper. In order to evaluate the asynchronous design a synchronous version of the algorithm was also designed. VHDL hardware description language was used in order to describe the algorithm. By using Synopsys commercial available tools the VHDL code was synthesized. After placing and routing both designs were fabricated with 0.6 μm CMOS technology. With a system clock of up to 8 MHz and a power supply of 5 V the two chips were tested and evaluated comparing with the software implementation of the IDEA algorithm. This new approach proves efficiently the lowest power consumption of the asynchronous implementation compared to the existing synchronous. Therefore, the asynchronous chip performs efficiently in Wireless Encryption Protocols and high speed networks.

  3. Behavioral Synthesis of Asynchronous Circuits Using Syntax Directed Translation as Backend

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard; Sparsø, Jens; Madsen, Jan

    2009-01-01

    of syntax directed translation, and which allows the designer to perform automatic design space exploration guided by area or speed constraints. The paper presents an asynchronous implementation template consisting of a data-path and a control unit and its implementation using the asynchronous hardware...... description language Balsa [1]. This ”conventional” template architecture allows us to adapt traditional synchronous synthesis techniques for resource sharing, scheduling, binding etc, to the domain of asynchronous circuits. A prototype tool has been implemented on top of the Balsa framework, and the method...... is illustrated through the implementation of a set of example circuits. The main contributions of the paper are: the fundamental idea, the template architecture and its implementation using asynchronous handshake components, and the implementation of a prototype tool....

  4. Violation of the equivalence principle for stressed bodies in asynchronous relativity

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Martins, R. de (Centro de Logica, Epistemologia e Historia da Ciencia, Campinas (Brazil))

    1983-12-11

    In the recently developed asynchronous formulation of the relativistic theory of extended bodies, the inertial mass of a body does not explicitly depend on its pressure or stress. The detailed analysis of the weight of a box filled with a gas and placed in a weak gravitational field shows that this feature of asynchronous relativity implies a breakdown of the equivalence between inertial and passive gravitational mass for stressed systems.

  5. Linearity, Persistence and Testing Semantics in the Asynchronous Pi-Calculus

    OpenAIRE

    Cacciagrano, Diletta; Flavio CORRADINI; Aranda, Jesus; Valencia, Frank,

    2007-01-01

    In [CSVV06] the authors studied the expressiveness of persistence in the asynchronous pi calculus (Api) wrt weak barbed congruence. The study is incomplete because it ignores the issue of divergence. In this paper we present an expressiveness study of persistence in the asynchronous pi-calculus (Api) wrt DeNicola and Hennesy's testing scenario which is sensitive to divergence. We consider Api and theree sub-languages of it, each capturing one source of persistence: the persistent-input calcul...

  6. Synaptotagmin-7 Is an Asynchronous Calcium Sensor for Synaptic Transmission in Neurons Expressing SNAP-23

    DEFF Research Database (Denmark)

    Weber, Jens P; Toft-Bertelsen, Trine L; Mohrmann, Ralf;

    2014-01-01

    Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive......-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein...

  7. Strict optical orthogonal codes for purely asynchronous code-division multiple-access applications.

    Science.gov (United States)

    Zhang, J G

    1996-12-10

    Strict optical orthogonal codes are presented for purely asynchronous optical code-division multiple-access (CDMA) applications. The proposed code can strictly guarantee the peaks of its cross-correlation functions and the sidelobes of any of its autocorrelation functions to have a value of 1 in purely asynchronous data communications. The basic theory of the proposed codes is given. An experiment on optical CDMA systems is also demonstrated to verify the characteristics of the proposed code. PMID:21151299

  8. Asynchronous growth and competition in a two-sex age-structured population model

    OpenAIRE

    Iannelli, Mimmo; Ripoll, Jordi

    2009-01-01

    Asynchronous exponential growth has been extensively studied in population dynamics. In this paper we find out the asymptotic behaviour in a non-linear age-dependent model which takes into account sexual reproduction interactions. The main feature of our model is that the non-linear process converges to a linear one as the solution becomes large, so that the population undergoes asynchronous growth. The steady states analysis and the corresponding stability analysis are completely made and ...

  9. On the basins of attraction of the regular autonomous asynchronous systems

    OpenAIRE

    Vlad, Serban E.

    2012-01-01

    The Boolean autonomous dynamical systems, also called regular autonomous asynchronous systems are systems whose 'vector field' is a function {\\Phi}:{0,1}^{n}{\\to}{0,1}^{n} and time is discrete or continuous. While the synchronous systems have their coordinate functions {\\Phi}_{1},...,{\\Phi}_{n} computed at the same time: {\\Phi},{\\Phi}{\\circ}{\\Phi},{\\Phi}{\\circ}{\\Phi}{\\circ}{\\Phi},... the asynchronous systems have {\\Phi}_{1},...,{\\Phi}_{n} computed independently on each other. The purpose of t...

  10. Document Flow Model: A Formal Notation for Modelling Asynchronous Web Services Composition

    OpenAIRE

    Yang, Jingtao; Cirstea, Corina; Henderson, Peter

    2005-01-01

    This paper presents a formal notation for modelling asynchronous web services composition, using context and coordination mechanisms. Our notation specifies the messages that can be handled by different web services, and describes a system of inter-related web services as the flow of documents between them. The notation allows the typical web services composition pattern, asynchronous messaging, and has the capability to deal with long-running service-to-service interactions and dynamic confi...

  11. Batch Secret Sharing for Secure Multi-party Computation in Asynchronous Network

    Institute of Scientific and Technical Information of China (English)

    HUANG Zheng; GONG Zheng; LI Qiang

    2009-01-01

    This paper proposes an efficient batch secret sharing protocol among n players resilient to t < n/4 players in asynchronous network. The construction of our protocol is along the line of Hirt's protocol which works in synchronous model. Compared with the method of using secret share protocol m times to share m secrets, our protocol is quite efficient. The protocol can be used to improve the efficiency of secure multi-party computation (MPC) greatly in asynchronous network.

  12. Simulating Quantitative Cellular Responses Using Asynchronous Threshold Boolean Network Ensembles

    Directory of Open Access Journals (Sweden)

    Shah Imran

    2011-07-01

    Full Text Available Abstract Background With increasing knowledge about the potential mechanisms underlying cellular functions, it is becoming feasible to predict the response of biological systems to genetic and environmental perturbations. Due to the lack of homogeneity in living tissues it is difficult to estimate the physiological effect of chemicals, including potential toxicity. Here we investigate a biologically motivated model for estimating tissue level responses by aggregating the behavior of a cell population. We assume that the molecular state of individual cells is independently governed by discrete non-deterministic signaling mechanisms. This results in noisy but highly reproducible aggregate level responses that are consistent with experimental data. Results We developed an asynchronous threshold Boolean network simulation algorithm to model signal transduction in a single cell, and then used an ensemble of these models to estimate the aggregate response across a cell population. Using published data, we derived a putative crosstalk network involving growth factors and cytokines - i.e., Epidermal Growth Factor, Insulin, Insulin like Growth Factor Type 1, and Tumor Necrosis Factor α - to describe early signaling events in cell proliferation signal transduction. Reproducibility of the modeling technique across ensembles of Boolean networks representing cell populations is investigated. Furthermore, we compare our simulation results to experimental observations of hepatocytes reported in the literature. Conclusion A systematic analysis of the results following differential stimulation of this model by growth factors and cytokines suggests that: (a using Boolean network ensembles with asynchronous updating provides biologically plausible noisy individual cellular responses with reproducible mean behavior for large cell populations, and (b with sufficient data our model can estimate the response to different concentrations of extracellular ligands. Our

  13. Mathematical Model of Asynchronous Machine in MATLAB Simulink

    Directory of Open Access Journals (Sweden)

    A A Ansari

    2010-05-01

    Full Text Available Different mathematical models have been used over the years to examine different problems associated with induction motors. These range from the simple equivalent circuit models to more complex d,q models and abc models which allow the inclusion of various forms of impedance and/or voltage unbalance. Recently, hybrid models have been developed which allow the inclusion of supply side unbalance but with the computational economy of the d,q models. This paper presents these models with typical results and provides guidelines for their use The dynamic simulation of small power induction motor based on mathematical modelling is proposed in this paper. The dynamic simulation is one of the key steps in the validation of the design process of the motor drive systems and it is needed for eliminating inadvertent design mistakes and the resulting error in the prototype construction and testing. This paper demonstrates the simulation of steady-state performance of induction motor by MATLAB Program Threephase induction motor is modeled and simulated with SIMULINK model.

  14. High performance control of an synchronous engine without speed indicator by direct control of the torque: Kalman filtering: control of the inverter commutation frequency; Commande haute performance d'un moteur asynchrone sans capteur de vitesse par controle direct du couple: filtrage de Kalman etendu du vecteur d'etat: controle de la frequence de commutation de l'onduleur

    Energy Technology Data Exchange (ETDEWEB)

    El Hassan, Ismail

    1999-07-01

    This thesis describes the development of a direct control of the torque and flow without a speed indicator for an asynchronous motor. The power is supplied by a two level inverter. The lack of mechanical sensor leads to a non linear simulation. This study is applied to a prototype. The obtained results show good static and dynamic performance of the speed regulator and the control robustness for the whole speed range. (A.L.B.)

  15. Enhancing ESL Learners Speaking Skills through Asynchronous Online Discussion Forum

    Directory of Open Access Journals (Sweden)

    Nadzrah Abu Bakar

    2013-05-01

    Full Text Available Communicating orally in a second or foreign language such as English can be a difficult task especially for the low proficiency learners as they may lack the confidence and feel shy and apprehensive when interacting verbally in the target language. This may hold them back from expressing themselves vocally though they are fully aware that in order to be fluent in the target language, they need to practise speaking not only in the classroom but also outside the classroom. This paper discusses the use of an asynchronous online discussion forum (AODF as a communication tool to assist the low proficiency ESL learners to build their confidence and practise using the target language orally. As an online discussion forum, the Multimedia Enhance Discussion Forum (MEDiF was specifically designed to be used by a selected group of low proficiency ESL learners at tertiary level for one academic semester. This online forum allows the learners to audio and video-record their discussions, listen to the recorded discussions and respond to their friends’ ideas and opinions. Interviews and observations of the discussions on the MEDiF were conducted to gather data. The findings generally indicate positive responses from the ESL learners although there were also some obstacles faced by them while utilizing the MEDiF.

  16. Asynchronous vehicle pose correction using visual detection of ground features

    Science.gov (United States)

    Harnarinesingh, Randy E. S.; Syan, Chanan S.

    2014-07-01

    The inherent noise associated with odometry manifests itself as errors in localization for autonomous vehicles. Visual odometry has been previously used in order to supplement classical vehicle odometry. However, visual odometry is limited in its ability to reduce errors in localization for large travel distances that entail the cumulative summing of individual frame-to-frame image errors. In this paper, a novel machine vision approach for tiled surfaces is proposed to address this problem. Tile edges in a laboratory environment are used to define a travel trajectory for the Quansar Qbot (autonomous vehicle) built on the iRobot iRoomba platform with a forward facing camera. Tile intersections are used to enable asynchronous error recovery for vehicle position and orientation. The proposed approach employs real-time image classification and is feasible for error mitigation for large travel distances. The average position error for an 8m travel distance using classical odometry was measured to be 0.28m. However, implementation of the proposed approach resulted in an error of 0.028m. The proposed approach therefore significantly reduces pose estimation error and could be used to supplement existing modalities such as GPS and Laser-based range sensors.

  17. Sparse asynchronous cortical generators can produce measurable scalp EEG signals.

    Science.gov (United States)

    von Ellenrieder, Nicolás; Dan, Jonathan; Frauscher, Birgit; Gotman, Jean

    2016-09-01

    We investigate to what degree the synchronous activation of a smooth patch of cortex is necessary for observing EEG scalp activity. We perform extensive simulations to compare the activity generated on the scalp by different models of cortical activation, based on intracranial EEG findings reported in the literature. The spatial activation is modeled as a cortical patch of constant activation or as random sets of small generators (0.1 to 3cm(2) each) concentrated in a cortical region. Temporal activation models for the generation of oscillatory activity are either equal phase or random phase across the cortical patches. The results show that smooth or random spatial activation profiles produce scalp electric potential distributions with the same shape. Also, in the generation of oscillatory activity, multiple cortical generators with random phase produce scalp activity attenuated on average only 2 to 4 times compared to generators with equal phase. Sparse asynchronous cortical generators can produce measurable scalp EEG. This is a possible explanation for seemingly paradoxical observations of simultaneous disorganized intracranial activity and scalp EEG signals. Thus, the standard interpretation of scalp EEG might constitute an oversimplification of the underlying brain activity. PMID:27262240

  18. Commande vectorielle d'un moteur asynchrone sans capteur

    Science.gov (United States)

    Ourth, T.

    1993-06-01

    A field-oriented control strategy for induction machines which does not use mechanical sensors is presented. The rotor flux is observed by a reduced-order Luenberger-type observer based on a model using a stator-fixed reference frame. An estimate of the rotation speed is derived from the flux vector, the measured stator currents and the field orientation angle. Simulations demonstrate that this control strategy performs well even in the presence of parameter variations up to ± 50% (resistances). Ce papier présente la commande par flux orienté d'une machine asynchrone sans capteur de vitesse ou de position. Le flux rotorique est évalué grâce à un observateur d'ordre réduit d'un type voisin de Luenberger travaillant dans un repère fixe statorique. L'estimation de la vitesse est obtenue à partir du module du flux rotorique, des courants statoriques mesurés et de l'angle d'orientation du flux rotorique. Cette étude basée sur des simulations démontre un comportement acceptable de la commande malgré la variation des paramètres comme les résistances de la machine.

  19. Obstacle avoidance in social groups: new insights from asynchronous models.

    Science.gov (United States)

    Croft, Simon; Budgey, Richard; Pitchford, Jonathan W; Wood, A Jamie

    2015-05-01

    For moving animals, the successful avoidance of hazardous obstacles is an important capability. Despite this, few models of collective motion have addressed the relationship between behavioural and social features and obstacle avoidance. We develop an asynchronous individual-based model for social movement which allows social structure within groups to be included. We assess the dynamics of group navigation and resulting collision risk in the context of information transfer through the system. In agreement with previous work, we find that group size has a nonlinear effect on collision risk. We implement examples of possible network structures to explore the impact social preferences have on collision risk. We show that any social heterogeneity induces greater obstacle avoidance with further improvements corresponding to groups containing fewer influential individuals. The model provides a platform for both further theoretical investigation and practical application. In particular, we argue that the role of social structures within bird flocks may have an important role to play in assessing the risk of collisions with wind turbines, but that new methods of data analysis are needed to identify these social structures. PMID:25833245

  20. A control strategy for induction motors fed from single phase supply

    DEFF Research Database (Denmark)

    Søndergård, Lars Møller

    It is often required that a three-phased asynchronous motor can run at variable speed, which makes it necessary to use a three-phase inverter driven from a DC-source. Today, most inverters are driven from the network using a simple diode bridge and an electrolytic capacitor. The problem with the...... simple diode bridge and the electrolytic capacitor is that current is only drawn for short periods, which gives rise to harmonic currents in the network. For small drive systems (motor+inverter), i.e. less than 1.5 kW, a single phase network outlet is often used. The author describes a method whereby the...

  1. A control strategy for induction motors fed from single phase supply

    OpenAIRE

    Søndergård, Lars Møller

    1993-01-01

    It is often required that a three-phased asynchronous motor can run at variable speed, which makes it necessary to use a three-phase inverter driven from a DC-source. Today, most inverters are driven from the network using a simple diode bridge and an electrolytic capacitor. The problem with the simple diode bridge and the electrolytic capacitor is that current is only drawn for short periods, which gives rise to harmonic currents in the network. For small drive systems (motor+inverter), i.e....

  2. Progresses in the Analysis of Stochastic 2D Cellular Automata: a Study of Asynchronous 2D Minority

    CERN Document Server

    Regnault, Damien; Thierry, Éric

    2007-01-01

    Cellular automata are often used to model systems in physics, social sciences, biology that are inherently asynchronous. Over the past 20 years, studies have demonstrated that the behavior of cellular automata drastically changed under asynchronous updates. Still, the few mathematical analyses of asynchronism focus on one-dimensional probabilistic cellular automata, either on single examples or on specific classes. As for other classic dynamical systems in physics, extending known methods from one- to two-dimensional systems is a long lasting challenging problem. In this paper, we address the problem of analysing an apparently simple 2D asynchronous cellular automaton: 2D Minority where each cell, when fired, updates to the minority state of its neighborhood. Our experiments reveal that in spite of its simplicity, the minority rule exhibits a quite complex response to asynchronism. By focusing on the fully asynchronous regime, we are however able to describe completely the asymptotic behavior of this dynamics...

  3. Multifocal Motor Neuropathy

    Science.gov (United States)

    ... Enhancing Diversity Find People About NINDS NINDS Multifocal Motor Neuropathy Information Page Table of Contents (click to ... being done? Clinical Trials Organizations What is Multifocal Motor Neuropathy? Multifocal motor neuropathy is a progressive muscle ...

  4. Motor Neuron Diseases

    Science.gov (United States)

    ... Awards Enhancing Diversity Find People About NINDS Motor Neuron Diseases Fact Sheet See a list of all ... can I get more information? What are motor neuron diseases? The motor neuron diseases (MNDs) are a ...

  5. Gross motor control

    Science.gov (United States)

    Gross motor control is the ability to make large, general movements (such as waving an arm or lifting a ... Gross motor control is a milestone in the development of an infant. Infants develop gross motor control before they ...

  6. iHadoop: Asynchronous Iterations Support for MapReduce

    KAUST Repository

    Elnikety, Eslam

    2011-08-01

    MapReduce is a distributed programming framework designed to ease the development of scalable data-intensive applications for large clusters of commodity machines. Most machine learning and data mining applications involve iterative computations over large datasets, such as the Web hyperlink structures and social network graphs. Yet, the MapReduce model does not efficiently support this important class of applications. The architecture of MapReduce, most critically its dataflow techniques and task scheduling, is completely unaware of the nature of iterative applications; tasks are scheduled according to a policy that optimizes the execution for a single iteration which wastes bandwidth, I/O, and CPU cycles when compared with an optimal execution for a consecutive set of iterations. This work presents iHadoop, a modified MapReduce model, and an associated implementation, optimized for iterative computations. The iHadoop model schedules iterations asynchronously. It connects the output of one iteration to the next, allowing both to process their data concurrently. iHadoop\\'s task scheduler exploits inter- iteration data locality by scheduling tasks that exhibit a producer/consumer relation on the same physical machine allowing a fast local data transfer. For those iterative applications that require satisfying certain criteria before termination, iHadoop runs the check concurrently during the execution of the subsequent iteration to further reduce the application\\'s latency. This thesis also describes our implementation of the iHadoop model, and evaluates its performance against Hadoop, the widely used open source implementation of MapReduce. Experiments using different data analysis applications over real-world and synthetic datasets show that iHadoop performs better than Hadoop for iterative algorithms, reducing execution time of iterative applications by 25% on average. Furthermore, integrating iHadoop with HaLoop, a variant Hadoop implementation that caches

  7. Towards Cloud-based Asynchronous Elasticity for Iterative HPC Applications

    Science.gov (United States)

    da Rosa Righi, Rodrigo; Facco Rodrigues, Vinicius; André da Costa, Cristiano; Kreutz, Diego; Heiss, Hans-Ulrich

    2015-10-01

    Elasticity is one of the key features of cloud computing. It allows applications to dynamically scale computing and storage resources, avoiding over- and under-provisioning. In high performance computing (HPC), initiatives are normally modeled to handle bag-of-tasks or key-value applications through a load balancer and a loosely-coupled set of virtual machine (VM) instances. In the joint-field of Message Passing Interface (MPI) and tightly-coupled HPC applications, we observe the need of rewriting source codes, previous knowledge of the application and/or stop-reconfigure-and-go approaches to address cloud elasticity. Besides, there are problems related to how profit this new feature in the HPC scope, since in MPI 2.0 applications the programmers need to handle communicators by themselves, and a sudden consolidation of a VM, together with a process, can compromise the entire execution. To address these issues, we propose a PaaS-based elasticity model, named AutoElastic. It acts as a middleware that allows iterative HPC applications to take advantage of dynamic resource provisioning of cloud infrastructures without any major modification. AutoElastic provides a new concept denoted here as asynchronous elasticity, i.e., it provides a framework to allow applications to either increase or decrease their computing resources without blocking the current execution. The feasibility of AutoElastic is demonstrated through a prototype that runs a CPU-bound numerical integration application on top of the OpenNebula middleware. The results showed the saving of about 3 min at each scaling out operations, emphasizing the contribution of the new concept on contexts where seconds are precious.

  8. Motor control for a brushless DC motor

    Science.gov (United States)

    Peterson, William J. (Inventor); Faulkner, Dennis T. (Inventor)

    1985-01-01

    This invention relates to a motor control system for a brushless DC motor having an inverter responsively coupled to the motor control system and in power transmitting relationship to the motor. The motor control system includes a motor rotor speed detecting unit that provides a pulsed waveform signal proportional to rotor speed. This pulsed waveform signal is delivered to the inverter to thereby cause an inverter fundamental current waveform output to the motor to be switched at a rate proportional to said rotor speed. In addition, the fundamental current waveform is also pulse width modulated at a rate proportional to the rotor speed. A fundamental current waveform phase advance circuit is controllingly coupled to the inverter. The phase advance circuit is coupled to receive the pulsed waveform signal from the motor rotor speed detecting unit and phase advance the pulsed waveform signal as a predetermined function of motor speed to thereby cause the fundamental current waveform to be advanced and thereby compensate for fundamental current waveform lag due to motor winding reactance which allows the motor to operate at higher speeds than the motor is rated while providing optimal torque and therefore increased efficiency.

  9. The Use of Efficient Broadcast Protocols in Asynchronous Distributed Systems. Ph.D. Thesis

    Science.gov (United States)

    Schmuck, Frank Bernhard

    1988-01-01

    Reliable broadcast protocols are important tools in distributed and fault-tolerant programming. They are useful for sharing information and for maintaining replicated data in a distributed system. However, a wide range of such protocols has been proposed. These protocols differ in their fault tolerance and delivery ordering characteristics. There is a tradeoff between the cost of a broadcast protocol and how much ordering it provides. It is, therefore, desirable to employ protocols that support only a low degree of ordering whenever possible. This dissertation presents techniques for deciding how strongly ordered a protocol is necessary to solve a given application problem. It is shown that there are two distinct classes of application problems: problems that can be solved with efficient, asynchronous protocols, and problems that require global ordering. The concept of a linearization function that maps partially ordered sets of events to totally ordered histories is introduced. How to construct an asynchronous implementation that solves a given problem if a linearization function for it can be found is shown. It is proved that in general the question of whether a problem has an asynchronous solution is undecidable. Hence there exists no general algorithm that would automatically construct a suitable linearization function for a given problem. Therefore, an important subclass of problems that have certain commutativity properties are considered. Techniques for constructing asynchronous implementations for this class are presented. These techniques are useful for constructing efficient asynchronous implementations for a broad range of practical problems.

  10. A Rewriting Approach to Replace Asynchronous ROMs with Synchronous Ones for the Circuits with Cycles

    Directory of Open Access Journals (Sweden)

    Yasuaki Ito

    2012-07-01

    Full Text Available

    Field Programmable Gate Arrays (FPGAs are a dominant implementation medium for digital circuits which are used  to embed a circuit designed by users instantly. FPGAs can be used for implementing parallel and hardware algorithms. Circuit design that minimizes the number of clock cycles is easy if we use asynchronous read operations. However, most of FPGAs support synchronous read operations, but do not support asynchronous read operations. The main contribution of this paper is to provide one of the potent approaches to resolve this problem. We assume that a circuit using asynchronous ROMs is given. In our previous work, we have presented a circuit rewriting algorithm to convert a circuit with asynchronous ROMs into an equivalent circuit with synchronous ones. The resulting circuit with synchronous ROMs can be embedded into FPGAs. However, this circuit rewriting algorithm can handle circuits represented by a directed acyclic graph and does not work for those with cycles. In this paper, we succeeded in relaxing the cycle-free condition of circuits. More specifically, we present an algorithm that automatically converts a circuit with cycles using asynchronous ROMs into an equivalent circuit using synchronous ROMs.

  11. Improving Learning of Programming Through E-Learning by Using Asynchronous Virtual Pair Programming

    Directory of Open Access Journals (Sweden)

    Sufian IDRIS

    2006-07-01

    Full Text Available The problem of learning programming subjects, especially through distance learning and E-Learning, has been widely reported in literatures. Many attempts have been made to solve these problems. This has led to many new approaches in the techniques of learning of programming. One of the approaches that have been proposed is the use of virtual pair programming (VPP. Most of the studies about VPP in distance learning or e-learning environment focus on the use of the synchronous mode of collaboration between learners. Not much research have been done about asynchronous VPP. This paper describes how we have implemented VPP and a research that has been carried out to study the effectiveness of asynchronous VPP for learning of programming. In particular, this research study the effectiveness of asynchronous VPP in the learning of object-oriented programming among students at Open University Malaysia (OUM. The result of the research has shown that most of the learners have given positive feedback, indicating that they are happy with the use of asynchronous VPP. At the same time, learners did recommend some extra features that could be added in making asynchronous VPP more enjoyable.

  12. Research on inverter test system of synchronous motor using modbus communication

    Science.gov (United States)

    Cao, Wenlun; Chen, Bei; He, Yuyao

    2013-03-01

    In this paper, the hardware architecture of the servo system composed by self-made inverter and permanent magnet synchronous motor is introduced as well as its measurement and control system software features. Basing on the Modbus-RTU protocols which contain the CRC data verification between IPC and the inverter, we have built a communication system. The measurement and control software of servo system are realized, which consists of self-made inverter and PMSM. Compared with the servo system which consists of Schindler's ATV31 inverter and SIMO's asynchronous motor, the results are given. The experiment parameters include harmonic content which is contained by phase current and voltage, and also the motor speed. The results show that the measurement and control system are stable and reliable. Both the harmonic content of the Inverter output and the motor speed meet the requirements.

  13. The Block Diagram for the Synchronous Motors used for the Compensation of the Reactive Power

    Directory of Open Access Journals (Sweden)

    Iulius Petrica

    2013-05-01

    Full Text Available The optimal control system for the compensation of the reactive power in an energetic consumer assembly is presented, containing one or more synchronous motors, connected to the same power bars in parallel, including asynchronous motors and static converters. The compensation of the reactive power absorbed from the system by the consumers is possible, using a optimal control system that controls the reactive power provided on the bars by the synchronous motors on condition that the power losses in the created whole are zero. A limited functional block diagram of the synchronous motor, which is the controlled object completed with the control circuits of the exciting tension and current is obtained having as set value the sum of all reactive currents of the consumers from the power assembly. The optimization is obtained using the module criterion of Kessler.

  14. Modelling and Simulation of Asynchronous Real-Time Systems using Timed Rebeca

    CERN Document Server

    Aceto, Luca; Ingolfsdottir, Anna; Reynisson, Arni Hermann; Sigurdarson, Steinar Hugi; Sirjani, Marjan; 10.4204/EPTCS.58.1

    2011-01-01

    In this paper we propose an extension of the Rebeca language that can be used to model distributed and asynchronous systems with timing constraints. We provide the formal semantics of the language using Structural Operational Semantics, and show its expressiveness by means of examples. We developed a tool for automated translation from timed Rebeca to the Erlang language, which provides a first implementation of timed Rebeca. We can use the tool to set the parameters of timed Rebeca models, which represent the environment and component variables, and use McErlang to run multiple simulations for different settings. Timed Rebeca restricts the modeller to a pure asynchronous actor-based paradigm, where the structure of the model represents the service oriented architecture, while the computational model matches the network infrastructure. Simulation is shown to be an effective analysis support, specially where model checking faces almost immediate state explosion in an asynchronous setting.

  15. On the Outage Behavior of Asynchronous OFDM DF and AF Cooperative Networks

    CERN Document Server

    Torbatian, Mehdi

    2009-01-01

    The outage behavior of various relaying protocols over a general one hop asynchronous cooperative network is examined when orthogonal frequency division multiplexing (OFDM) is used to combat synchronization error among the relays. We consider non-orthogonal selection decode-and-forward (NSDF), orthogonal selection decode-and-forward (OSDF), non-orthogonal amplify-and-forward (NAF), and orthogonal amplify-and-forward (OAF) relaying protocols and analyze the diversity multiplexing gain tradeoff (DMT) in all scenarios. The transmitting nodes cooperatively construct an asynchronous OFDM space-time code by re-sending the source messages over a common time interval and a common frequency bandwidth. It is shown that in decode-and-forward (DF) type protocols, the asynchronous network provides a diversity gain greater than or equal to the one of the corresponding synchronous network in the limit of code word length and throughout the range of multiplexing gain. In amplify-and-forward (AF) type protocols, in which the ...

  16. The design of an asynchronous Tiny RISC TM/TR4101 microprocessor core

    DEFF Research Database (Denmark)

    Christensen, Kåre Tais; Jensen, P.; Korger, P.;

    1998-01-01

    This paper presents the design of an asynchronous version of the TR4101 embedded microprocessor core developed by LSI Logic Inc. The asynchronous processor, called ARISC, was designed using the same CAD tools and the same standard cell library that was used to implement the TR4101. The paper...... reports on the design methodology, the architecture, the implementation, and the performance of the ARISC. This includes a comparison with the TR4101, and a detailed breakdown of the power consumption in the ARISC. ARISC is our first attempt at an asynchronous implementation and a number of simplifying...... decisions were made up front. Throughout the entire design we use four-phase handshaking in combination with a normally opaque latch controller. All logic is implemented using static logic standard cells. Despite this the ARISC performs surprisingly well: In 0.35 μm CMOS performance is 74-123 MIPS depending...

  17. Dual stator winding variable speed asynchronous generator: magnetic equivalent circuit with saturation, FEM analysis and experiments

    Science.gov (United States)

    Tutelea, L. N.; Muntean, N.; Deaconu, S. I.; Cunţan, C. D.

    2016-02-01

    The authors carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behaviour in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings, FEM validation of parameters and characteristics with free FEMM 4.2 computing software and the practice experimental tests for verifying them. Issue is limited to three phase range of double stator winding cage-asynchronous generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA].

  18. EXPERIMENTAL STUDY OF THE ASYNCHRONOUS MULTISPLITTING RELAXATION METHODS FOR THE LINEAR COMPLEMENTARITY PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Zhong-zhi Bai

    2002-01-01

    We study the numerical behaviours of the relaxed asynchronous multisplitting methods for the linear complementarity problems by solving some typical problems from practical applications on a real multiprocessor system. Numerical results show that the parallel multisplitting relaxation methods always perform much better than the corresponding sequential alternatives, and that the asynchronous multisplitting relaxation methods often outperform their corresponding synchronous counterparts. Moreover, the two-sweep relaxed multisplitting methods have better convergence properties than their corresponding one-sweep relaxed ones in the sense that they have larger convergence domains and faster convergence speeds. Hence, the asynchronous multisplitting unsymmetric relaxation iterations should be the methods of choice for solving the large sparse linear complementarity problems in the parallel computing environments.

  19. Concerted and asynchronous mechanism of ground state proton transfer in alcohol mediated 7-hydroxyquinoline

    International Nuclear Information System (INIS)

    Highlights: • Reaction rate constants obtained by DFT agree with experimental ones quite well. • Experimental postulate of concerted and asynchronous GSPT was confirmed. • The GSPT reaction can be decomposed into three asynchronous steps. - Abstract: Alcohols mediated 7-hydroxyquinoline (7-HQ) complex has received enormous attractions on the issue of proton transfer reaction in the ground and excited states. In the present paper, concentrating on the ground state proton transfer (GSPT), density functional theory (DFT) calculations were carried out to investigate the intrinsic insight into the reaction mechanism. We found that the GSPT is concerted and asynchronous process and can be accelerated by more acidic alcohol. Such GSPT was initiated by the proton transfer from alcohol to keto group of 7-HQ and finished by the proton transfer from nitrogen to alcohol. Our findings were in agreement with experimental conclusions quite well. Our results would be helpful to understand the proton transfer reaction for 7-HQ and related systems

  20. Asynchronous Video Interviewing as a New Technology in Personnel Selection: The Applicant's Point of View.

    Science.gov (United States)

    Brenner, Falko S; Ortner, Tuulia M; Fay, Doris

    2016-01-01

    The present study aimed to integrate findings from technology acceptance research with research on applicant reactions to new technology for the emerging selection procedure of asynchronous video interviewing. One hundred six volunteers experienced asynchronous video interviewing and filled out several questionnaires including one on the applicants' personalities. In line with previous technology acceptance research, the data revealed that perceived usefulness and perceived ease of use predicted attitudes toward asynchronous video interviewing. Furthermore, openness revealed to moderate the relation between perceived usefulness and attitudes toward this particular selection technology. No significant effects emerged for computer self-efficacy, job interview self-efficacy, extraversion, neuroticism, and conscientiousness. Theoretical and practical implications are discussed. PMID:27378969

  1. THE ROLE OF OFFLINE METALANGUAGE TALK IN ASYNCHRONOUS COMPUTER-MEDIATED COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Keiko Kitade

    2008-02-01

    Full Text Available In order to demonstrate how learners utilize the text-based asynchronous attributes of the Bulletin Board System, this study explored Japanese-as-a-second-language learners' metalanguage episodes (Swain & Lapkin, 1995, 1998 in offline verbal peer speech and online asynchronous discussions with their Japanese key pals. The findings suggest the crucial role of offline collaborative dialogue, the interactional modes in which the episodes occur, and the unique discourse structure of metalanguage episodes concerning online and offline interactions. A high score on the posttest also suggests the high retention of linguistic knowledge constructed through offline peer dialogue. In the offline mode, the learners were able to collaboratively construct knowledge with peers in the stipulated time, while simultaneously focusing on task content in the online interaction. The retrospective interviews and questionnaires reveal the factors that could affect the benefits of the asynchronous computer-mediated communication medium for language learning.

  2. Router Designs for an Asynchronous Time-Division-Multiplexed Network-on-Chip

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens; Sørensen, Rasmus Bo; Goossens, Kees

    In this paper we explore the design of an asynchronous router for a time-division-multiplexed (TDM) network-on-chip (NOC) that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs are either...... synchronous or mesochronous, but both approaches have their limitations: a globally synchronous NOC is no longer feasible in today's sub micron technologies and a mesochronous NOC requires special FIFO-based synchronizers in all input ports of all routers in order to accommodate for clock phase differences....... This adds hardware complexity and increases area and power consumption. We propose to use asynchronous routers in order to achieve a simpler, more robust and globally-asynchronous NOC, and this represents an unexplored point in the design space. The paper presents a range of alternative router designs...

  3. Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering

    OpenAIRE

    Suraj; Purnendu Tiwari; Subhojit Ghosh; Rakesh Kumar Sinha

    2015-01-01

    Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means c...

  4. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1992-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  5. Network evolution induced by asynchronous stimuli through spike-timing-dependent plasticity.

    Directory of Open Access Journals (Sweden)

    Wu-Jie Yuan

    Full Text Available In sensory neural system, external asynchronous stimuli play an important role in perceptual learning, associative memory and map development. However, the organization of structure and dynamics of neural networks induced by external asynchronous stimuli are not well understood. Spike-timing-dependent plasticity (STDP is a typical synaptic plasticity that has been extensively found in the sensory systems and that has received much theoretical attention. This synaptic plasticity is highly sensitive to correlations between pre- and postsynaptic firings. Thus, STDP is expected to play an important role in response to external asynchronous stimuli, which can induce segregative pre- and postsynaptic firings. In this paper, we study the impact of external asynchronous stimuli on the organization of structure and dynamics of neural networks through STDP. We construct a two-dimensional spatial neural network model with local connectivity and sparseness, and use external currents to stimulate alternately on different spatial layers. The adopted external currents imposed alternately on spatial layers can be here regarded as external asynchronous stimuli. Through extensive numerical simulations, we focus on the effects of stimulus number and inter-stimulus timing on synaptic connecting weights and the property of propagation dynamics in the resulting network structure. Interestingly, the resulting feedforward structure induced by stimulus-dependent asynchronous firings and its propagation dynamics reflect both the underlying property of STDP. The results imply a possible important role of STDP in generating feedforward structure and collective propagation activity required for experience-dependent map plasticity in developing in vivo sensory pathways and cortices. The relevance of the results to cue-triggered recall of learned temporal sequences, an important cognitive function, is briefly discussed as well. Furthermore, this finding suggests a potential

  6. FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

    Science.gov (United States)

    Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

    2014-09-01

    Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to

  7. Good Quality Discussion Is Necessary but Not Sufficient in Asynchronous Tuition: A Brief Narrative Review of the Literature

    Science.gov (United States)

    Fear, William James; Erikson-Brown, Andrew

    2014-01-01

    Online learning is a growing field of education with a corresponding increase in the use of asynchronous discussion. Asynchronous discussion is a form of interaction that is mediated rather than direct and where there is a time lag in the interactions between discussants. In this paper we conducted a brief narrative review of the literature on…

  8. Enhancing Discussions in the Asynchronous Online Classroom: The Lack of Face-to-Face Interaction Does Not Lessen the Lesson

    Science.gov (United States)

    Comer, Debra R.; Lenaghan, Janet A.

    2013-01-01

    This article addresses educators' concerns about using asynchronous online discussions in lieu of face-to-face discussions. Drawing from research on asynchronous online education and Bloom's taxonomy, the authors introduce the system of "original examples" and "value-added comments" that they have developed to promote engaging and meaningful…

  9. Evaluation of asynchronous E-learning in the geography curriculum: enriching learning quality in Saudi high schools

    OpenAIRE

    Al Dobaikhi, Hend; Woollard, John

    2011-01-01

    The impacts of emerging ICT into educational curricula Asynchronous discussion forum Discussion groups via e-learning environment Posting questions and comments Self-efficacy in asynchronous e-learning Web community participation Collaborative learning can be fostered Positive impacts on objectives of educational curriculum

  10. On Input-to-State Stability of Switched Stochastic Nonlinear Systems Under Extended Asynchronous Switching.

    Science.gov (United States)

    Kang, Yu; Zhai, Di-Hua; Liu, Guo-Ping; Zhao, Yun-Bo

    2016-05-01

    An extended asynchronous switching model is investigated for a class of switched stochastic nonlinear retarded systems in the presence of both detection delay and false alarm, where the extended asynchronous switching is described by two independent and exponentially distributed stochastic processes, and further simplified as Markovian. Based on the Razumikhin-type theorem incorporated with average dwell-time approach, the sufficient criteria for global asymptotic stability in probability and stochastic input-to-state stability are given, whose importance and effectiveness are finally verified by numerical examples. PMID:26068932

  11. A Scheduling Discipline for Latency and Bandwidth Guarantees in Asynchronous Network-on-Chip

    DEFF Research Database (Denmark)

    Bjerregaard, Tobias; Sparsø, Jens

    2005-01-01

    Guaranteed services (GS) are important in that they provide predictability in the complex dynamics of shared communication structures. This paper discusses the implementation of GS in asynchronous Network-on-Chip. We present a novel scheduling discipline called Asynchronous Latency Guarantee (ALG......) scheduling, which provides latency and bandwidth guarantees in accessing a shared media, e.g. a physical link shared between a number of virtual channels. ALG overcomes the drawbacks of existing scheduling disciplines, in particular the coupling between latency and bandwidth guarantees. A 0.12 &956;m CMOS...

  12. Time-Efficient Read/Write Register in Crash-prone Asynchronous Message-Passing Systems

    OpenAIRE

    Mostefaoui, Achour; Raynal, Michel

    2016-01-01

    The atomic register is certainly the most basic object of computing science. Its implementation on top of an n-process asynchronous message-passing system has received a lot of attention. It has been shown that t \\textless{} n/2 (where t is the maximal number of processes that may crash) is a necessary and sufficient requirement to build an atomic register on top of a crash-prone asynchronous message-passing system. Considering such a context, this paper visits the notion of a fast implementa...

  13. Motor Priming in Neurorehabilitation

    OpenAIRE

    Stoykov, Mary Ellen; Madhavan, Sangeetha

    2015-01-01

    Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few ...

  14. 浅谈潜水电动机的型式及设计特点%Types and Design Features of Submersible Motors

    Institute of Scientific and Technical Information of China (English)

    黄家友; 鲍晓华; 荚小健

    2011-01-01

    As a special three phase asynchronous motor, the submersible motor has its unique features. The paper introduces the classification of submersible motors, taking water filled submersible motors as example analyses the feature of structure design and electromagnetic design, and finally discusses the progressive trend of submersible motors and pressing task which submersible motors industry faced.%作为一种特殊型式的三相异步电机,潜水电动机有其独特的特点.本文主要介绍了潜水电动机的分类,以充水式潜水电动机为例分析了潜水电动机的结构和电磁设计特点,探讨了潜水电机的发展趋势和潜水电机行业面临的紧迫任务.

  15. A model of asynchronous left ventricular relaxation predicting the bi-exponential pressure decay

    NARCIS (Netherlands)

    R.W. Brower (Ronald); S. Meij (Simon); P.W.J.C. Serruys (Patrick)

    1983-01-01

    textabstractA new model for the pressure relaxation of the left ventricle is proposed. The model presumes that the myocardium relaxes asynchronously, but that when regions begin to relax, after a delay, the local wall stress decays as a mono-exponential process. This formulation results in an appare

  16. Synchronous and Asynchronous E-Language Learning: A Case Study of Virtual University of Pakistan

    Science.gov (United States)

    Perveen, Ayesha

    2016-01-01

    This case study evaluated the impact of synchronous and asynchronous E-Language Learning activities (ELL-ivities) in an E-Language Learning Environment (ELLE) at Virtual University of Pakistan. The purpose of the study was to assess e-language learning analytics based on the constructivist approach of collaborative construction of knowledge. The…

  17. An Approach for Asynchronous Awareness Support in Collaborative Non-Linear Storytelling

    NARCIS (Netherlands)

    Schumann, J.; Buttler, T.; Lukosch, S.

    2012-01-01

    Workspace awareness support is mandatory for group support systems. It allows users not only to follow actions of others, but to understand and respond to any changes others make to the workspace. In this paper, we present a novel approach for asynchronous awareness support by offering different fil

  18. An Examination of Computer Engineering Students' Perceptions about Asynchronous Discussion Forums

    Science.gov (United States)

    Ozyurt, Ozcan; Ozyurt, Hacer

    2013-01-01

    This study was conducted in order to reveal the usage profiles and perceptions of Asynchronous Discussion Forums (ADFs) of 126 computer engineering students from the Computer Engineering Department in a university in Turkey. By using a mixed methods research design both quantitative and qualitative data were collected and analyzed. Research…

  19. An iron free asynchronous pulsed generator for the production of pulsed high magnetic fields

    International Nuclear Information System (INIS)

    The production of long pulsed high fields (> 500 kgaus) with (tau > 1 s) with cryogenic coils requires an initial energy source of several megajoules. Iron free asynchronous pulsed generators are particulary well adapted to this application as they are able to produce this energy at a very competitive price

  20. A low-power asynchronous data-path for a FIR filter bank

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1996-01-01

    This paper describes a number of design issues relating to the implementation of low-power asynchronous signal processing circuits. Specifically, the paper addresses the design of a dedicated processor structure that implements an audio FIR filter bank which is part of an industrial application...

  1. Synthesis and Layout of an Asynchronous Network-on-Chip using Standard EDA Tools

    DEFF Research Database (Denmark)

    Müller, Christoph; Kasapaki, Evangelia; Sørensen, Rasmus Bo;

    2014-01-01

    is the key role that clock signals play in specifying time-constraints for the synthesis. In this paper explain how we handled the synthesis and layout of an asynchronous network-on-chip for a multi-core platform. Focus is on the design process while the actual NOC-design and its performance are...

  2. "Intentional Repetition" and Learning Style: Increasing Efficient and Cohesive Interaction in Asynchronous Online Discussions

    Science.gov (United States)

    Topcu, Abdullah

    2008-01-01

    This study verified the efficacy of the intentional repetition technique in improving interaction in asynchronous online discussions by taking into account the learning styles of the participants. A conceptual framework served for the development of the technique, which conceptualises efficient and cohesive interaction on a continuum of process…

  3. Visual Search in a Multi-Element Asynchronous Dynamic (MAD) World

    Science.gov (United States)

    Kunar, Melina A.; Watson, Derrick G.

    2011-01-01

    In visual search tasks participants search for a target among distractors in strictly controlled displays. We show that visual search principles observed in these tasks do not necessarily apply in more ecologically valid search conditions, using dynamic and complex displays. A multi-element asynchronous dynamic (MAD) visual search was developed in…

  4. Comparative Analysis of Preservice Teachers' Reflective Thinking in Synchronous versus Asynchronous Online Case Discussions

    Science.gov (United States)

    Levin, Barbara B.; He, Ye; Robbins, Holly H.

    2006-01-01

    This study was undertaken to better understand the nature of preservice teachers' reflective thinking during case discussions about classroom management in two online formats: synchronous versus asynchronous. Findings indicated that when participants engaged in synchronous online case discussions they had higher levels of critical reflection than…

  5. Defining the Symmetry of the Universal Semi-Regular Autonomous Asynchronous Systems

    Directory of Open Access Journals (Sweden)

    Serban E. Vlad

    2012-02-01

    Full Text Available The regular autonomous asynchronous systems are the non-deterministic Boolean dynamical systems and universality means the greatest in the sense of the inclusion. The paper gives four definitions of symmetry of these systems in a slightly more general framework, called semi-regularity, and also many examples.

  6. Flipping the Online Classroom with Web 2.0: The Asynchronous Workshop

    Science.gov (United States)

    Cummings, Lance

    2016-01-01

    This article examines how Web 2.0 technologies can be used to "flip" the online classroom by creating asynchronous workshops in social environments where immediacy and social presence can be maximized. Using experience teaching several communication and writing classes in Google Apps (Google+, Google Hangouts, Google Drive, etc.), I…

  7. Designing a Discussion Environment to Enhance Connectivity and Sustainability in Asynchronous Online Discussion

    Science.gov (United States)

    Gao, Fei

    2011-01-01

    Lack of connectivity and sustainability are two common problems in asynchronous online discussions. In this paper, the author proposes that the two problems may have to do with the structure of threaded forums, that is, the design of threaded forums may constrain participants from having well-connected and sustained discussions. A new discussion…

  8. Cooperative Learning in Graduate Student Projects: Comparing Synchronous versus Asynchronous Collaboration

    Science.gov (United States)

    Strang, Kenneth

    2013-01-01

    Cooperative learning was applied in a graduate project management course to compare the effectiveness of asynchronous versus synchronous online team meetings. An experiment was constructed to allocate students to project teams while ensuring there was a balance of requisite skills, namely systems analysis and design along with HTML/Javascript…

  9. Multithreaded Asynchronous Graph Traversal for In-Memory and Semi-External Memory

    KAUST Repository

    Pearce, Roger

    2010-11-01

    Processing large graphs is becoming increasingly important for many domains such as social networks, bioinformatics, etc. Unfortunately, many algorithms and implementations do not scale with increasing graph sizes. As a result, researchers have attempted to meet the growing data demands using parallel and external memory techniques. We present a novel asynchronous approach to compute Breadth-First-Search (BFS), Single-Source-Shortest-Paths, and Connected Components for large graphs in shared memory. Our highly parallel asynchronous approach hides data latency due to both poor locality and delays in the underlying graph data storage. We present an experimental study applying our technique to both In-Memory and Semi-External Memory graphs utilizing multi-core processors and solid-state memory devices. Our experiments using synthetic and real-world datasets show that our asynchronous approach is able to overcome data latencies and provide significant speedup over alternative approaches. For example, on billion vertex graphs our asynchronous BFS scales up to 14x on 16-cores. © 2010 IEEE.

  10. Credit Hours with No Set Time: A Study of Credit Policies in Asynchronous Online Education

    Science.gov (United States)

    Prasuhn, Frederick Carl

    2014-01-01

    U.S. public university system policies were examined to learn how credit hours were determined for asynchronous online education. Findings indicated that (a) credit hour meaning and use are not consistent, (b) primary responsibility for credit hour decisions was at the local level, and (c) no policies exist to guide credit hour application for…

  11. The Role of Beliefs and Motivation in Asynchronous Online Learning in College-Level Classes

    Science.gov (United States)

    Xie, Kui; Huang, Kun

    2014-01-01

    Epistemic and learning beliefs were found to affect college students' cognitive engagement and study strategies, as well as motivation in classroom settings. However, the relationships between epistemic and learning beliefs, motivation, learning perception, and students' actual learning participation in asynchronous online settings have been…

  12. The Role of Technology-Based Scaffolding in Problem-Based Online Asynchronous Discussion

    Science.gov (United States)

    Ak, Serife

    2016-01-01

    This study examined the effects of technology-based scaffolds that were composed through the use of the seven-stage, problem-based learning strategy on knowledge construction in a problem-based online asynchronous discussion. In a quasi-experimental setting, 60 students in an undergraduate Instructional Technology and Material Design course were…

  13. Defining the Symmetry of the Universal Semi-Regular Autonomous Asynchronous Systems

    OpenAIRE

    Vlad, Serban E.

    2012-01-01

    The regular autonomous asynchronous systems are the non-deterministic Boolean dynamical systems and universality means the greatest in the sense of the inclusion. The paper gives four definitions of symmetry of these systems in a slightly more general framework, called semi-regularity, and also many examples.

  14. A Model for Evaluating the Process of Learning in Asynchronous Computer Conferencing.

    Science.gov (United States)

    Schrire, Sarah

    2003-01-01

    Presents a qualitative multiple-case study of three online asynchronous computer conferences that were part of a doctoral program at Nova Southeastern University. Examines the learning process from the points of view of interaction, cognition, and discourse analysis and proposes a model for assessing sociocognitive processes in computer…

  15. A Study of Asynchronous and Synchronous Discussion on Cognitive Maps in a Distributed Learning Environment.

    Science.gov (United States)

    Bhattacharya, Madhumita

    This paper reports on a comparative study of the use of asynchronous (bulletin board) and synchronous (chat) discussion on three learning units based on the cognitive maps developed by the learners. Cognitive maps have been found to be an effective tool for learners for discussion in a distributed learning environment. Cognitive maps provided…

  16. Asynchronous P300 classification in a reactive brain-computer interface during an outlier detection task

    Science.gov (United States)

    Krumpe, Tanja; Walter, Carina; Rosenstiel, Wolfgang; Spüler, Martin

    2016-08-01

    Objective. In this study, the feasibility of detecting a P300 via an asynchronous classification mode in a reactive EEG-based brain-computer interface (BCI) was evaluated. The P300 is one of the most popular BCI control signals and therefore used in many applications, mostly for active communication purposes (e.g. P300 speller). As the majority of all systems work with a stimulus-locked mode of classification (synchronous), the field of applications is limited. A new approach needs to be applied in a setting in which a stimulus-locked classification cannot be used due to the fact that the presented stimuli cannot be controlled or predicted by the system. Approach. A continuous observation task requiring the detection of outliers was implemented to test such an approach. The study was divided into an offline and an online part. Main results. Both parts of the study revealed that an asynchronous detection of the P300 can successfully be used to detect single events with high specificity. It also revealed that no significant difference in performance was found between the synchronous and the asynchronous approach. Significance. The results encourage the use of an asynchronous classification approach in suitable applications without a potential loss in performance.

  17. Anonymity to Promote Peer Feedback: Pre-Service Teachers' Comments in Asynchronous Computer-Mediated Communication

    Science.gov (United States)

    Howard, Craig D.; Barrett, Andrew F.; Frick, Theodore W.

    2010-01-01

    In this quasi-experimental case study, we compared five sections of a basic undergraduate technology course. Within an asynchronous web forum, pre-service teachers wrote short critiques of websites designed by their classmates. This peer feedback was provided anonymously by students in two classes (n = 35) whereas providers and recipients of peer…

  18. Socialization in the "Virtual Hallway": Instant Messaging in the Asynchronous Web-Based Distance Education Classroom.

    Science.gov (United States)

    Nicholson, Scott

    2002-01-01

    Examined differences in communication between masters degree students at Syracuse University who used instant messaging (IM) services and those who did not in the same asynchronous distance education Web-based course. Results showed that students who used IM found it easier to communicate and felt a stronger sense of community. (Author/LRW)

  19. Performance comparison of asynchronous orthogonal multi-carrier CDMA in frequency selective channel

    OpenAIRE

    Xiang, G; Ng, TS

    1998-01-01

    Bit error rate (BER) performance of an asynchronous multi-carrier code division multiple access (MC-CDMA) system for the uplink of the mobile communication system with equal gain combining and maximum ratio combining are obtained. Given a fixed bandwidth frequency selective channel, performance of MC-CDMA is compared with that of conventional CDMA and MC-DS-CDMA in numerical results.

  20. Asynchronous Orthogonal Multi-Carrier CDMA Using Equal Gain Combining in Multipath Rayleigh Fading Channel

    OpenAIRE

    Xiang, G; Ng, TS

    1998-01-01

    Performance of an asynchronous orthogonal multi-carrier code division multiple access (MC-CDMA) system for the reverse link of the mobile communication system with equal gain combining is obtained. The performance of MC-CDMA is compared with that of conventional CDMA and MC-DS-CDMA in numerical results in a multipath Rayleigh fading channel.

  1. Pedagogical Dimensions of Effective Online Asynchronous Teacher Communication in Higher Education

    NARCIS (Netherlands)

    A. Smits; J. Voogt

    2015-01-01

    In this research teacher behaviour in online asynchronous discussions is studied. To this end teachers’ online messages were analyzed and correlated to measures of student satisfaction. Findings show a positive relation between student satisfaction and the presence of content knowledge, multiple ack

  2. A Study of Synchronous versus Asynchronous Collaboration in an Online Business Writing Class

    Science.gov (United States)

    Mabrito, Mark

    2006-01-01

    A case study examined the collaborative experiences of students in an online business writing classroom. The purpose was to examine the same groups of students working on collaborative writing assignments in both a synchronous (real-time) and an asynchronous (non-real-time) discussion forum. This study focused on examining the amount, pattern, and…

  3. Asynchronous Knowledge Sharing and Conversation Interaction Impact on Grade in an Online Business Course

    Science.gov (United States)

    Strang, Kenneth David

    2011-01-01

    Student knowledge sharing and conversation theory interactions were coded from asynchronous discussion forums to measure the effect of learning-oriented utterances on academic performance. The sample was 3 terms of an online business course (in an accredited MBA program) at a U.S.-based university. Correlation, stepwise regression, and multiple…

  4. Comparing Asynchronous Online Discussions and Face-to-Face Discussions in a Classroom Setting

    Science.gov (United States)

    Wang, Qiyun; Woo, Huay Lit

    2007-01-01

    The purpose of this study is to investigate the perceived differences between asynchronous online discussions and face-to-face discussions in a classroom setting. The students' reflections were analysed by following a qualitative research approach. The results showed that atmosphere, response, efficiency, interactivity and communication were the…

  5. VOLTAGE REGULATORS AND FREQUENCY OF CURRENT OF ASYNCHRONOUS GENERATORS OF WIND POWER INSTALLATIONS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2013-10-01

    Full Text Available In the article we have considered the technical solutions of voltage regulators and the frequency of current of the asynchronous generators of the wind power installations executed with the help of the direct frequency transformers. The comparative analysis of them has been carried out as well

  6. Asynchronous Pipeline Micro—Control—Unit (MCU) Chip Design

    Institute of Scientific and Technical Information of China (English)

    ZHOUQian; XUKe; MINHao

    2003-01-01

    The work of this paper includes a researchon asynch ronous design methodology, and a design and implementation of an asynchronous 8-Bit micro-control-unit (MCU). This paper introduces a new application of New-Instruction-Fetching method to detect new instruc-tion which makes this chip fit for demand changeable sys-tem. The instruction set of this asynchronous MCU is compatible with PIC16C6X (Sicrochip Technology Inc).This paper also introduces a new architecture of pipeline,which increases the average speed of chip operation. The asynchronous low power MCU has been fabricated with CSMC (central semiconductor manufacturing corporation)0.6μm CMOS process in Aug 2001. The chip size is about 1.60mm*2.00mm (without taking account of PAD size).Now the test work has been accomplished and the test-ing result of this chip is also presented. The testing result shows that the asynchronous architecture could fulfill all the expected functions, additionally with higher processs peed and lower power consumption than its synchronous counterpart under the same supply voltage.

  7. Use of Podcasting as an Innovative Asynchronous E-Learning Tool for Students

    Science.gov (United States)

    Jalali, Alireza; Leddy, John; Gauthier, Martin; Sun, Rong; Hincke, Maxwell; Carnegie, Jacqueline

    2011-01-01

    Podcasting is an innovative, asynchronous communication tool. A pilot study was conducted to assess the utility of podcasting as an educational tool for undergraduate medical students. A paper-and-pencil questionnaire was developed and distributed to the 40 first-year students enrolled in the francophone stream of the medical curriculum at the…

  8. Effects of Asynchronous Music on Students' Lesson Satisfaction and Motivation at the Situational Level

    Science.gov (United States)

    Digelidis, Nikolaos; Karageorghis, Costas I.; Papapavlou, Anastasia; Papaioannou, Athanasios G.

    2014-01-01

    The aim of this study was to examine the effects of asynchronous (background) music on senior students' motivation and lesson satisfaction at the situational level. A counterbalanced mixed-model design was employed with two factors comprising condition (three levels) and gender (two levels). Two hundred students (82 boys, 118 girls; M…

  9. Tagging Thinking Types in Asynchronous Discussion Groups: Effects on Critical Thinking

    Science.gov (United States)

    Schellens, T.; Van Keer, H.; De Wever, B.; Valcke, M.

    2009-01-01

    The present study focuses on the use of thinking types as a possible way to structure university students' discourse in asynchronous discussion groups and consequently promote their learning. More specifically, the aim of the study is to determine how requiring students to label their contributions by means of De Bono's (1991) thinking hats…

  10. An Asynchronous P300 BCI With SSVEP-Based Control State Detection

    DEFF Research Database (Denmark)

    Panicker, Rajesh C.; Puthusserypady, Sadasivan; Sun, Ying

    2011-01-01

    In this paper, an asynchronous brain–computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEPs) paradigms is proposed. The information transfer is accomplished using P300 event-related potential paradigm and the control state (CS) detection is achieved...

  11. Research Notes ~ Simulating the Computer Science Closed Laboratory in an Asynchronous Learning Network

    Directory of Open Access Journals (Sweden)

    Timothy Margush

    2002-10-01

    Full Text Available The quiz tool that is part of the WebCT package is used to provide an asynchronous simulation of a (synchronous closed laboratory experience to beginner computer science students. The technique suggested in this paper and which may be applied to other disciplines, offers students a guided path through an exploratory, discovery based learning experience.

  12. Facing Off: Comparing an In-Person Library Orientation Lecture with an Asynchronous Online Library Orientation

    Science.gov (United States)

    Gall, Dan

    2014-01-01

    A study to compare the effectiveness of an in-person library orientation with an online asynchronous orientation was conducted with three sections of Social Work Research Methods, a required course in the University of Iowa's Master of Social Work program. Two sections of the course received an online orientation involving short videos, text…

  13. Thematic Analysis of the "Games" Students Play in Asynchronous Learning Environments

    Science.gov (United States)

    MacMillan, Thalia; Forte, Michele; Grant, Cynthia

    2014-01-01

    The dynamics of the student-student relationship within the asynchronous online classroom, as evidenced by conversations in an online discussion board, is a balancing act potentially more complex than those occurring in real-time. In order for learning to truly be considered effective, a collaborative, safe environment needs to exist among…

  14. Examining Facilitators' Habits of Mind in an Asynchronous Online Discussion Environment: A Two Cases Study

    Science.gov (United States)

    Cheung, Wing Sum; Hew, Khe Foon

    2010-01-01

    Asynchronous online discussion has been widely used by faculty members and students in schools and universities. Previous research has examined how factors such as the discussion activity, knowledge about the discussion topic, and the behaviour of other participants can affect learner participation. This study explored student facilitators'…

  15. Router Designs for an Asynchronous Time-Division-Multiplexed Network-on-Chip

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens; Sørensen, Rasmus Bo;

    2013-01-01

    In this paper we explore the design of an asynchronous router for a time-division-multiplexed (TDM) network-on-chip (NOC) that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs are either...

  16. Developing Asynchronous Online Courses: Key Instructional Strategies in a Social Metacognitive Constructivist Learning Trajectory

    Science.gov (United States)

    Niess, Margaret; Gillow-Wiles, Henry

    2013-01-01

    This qualitative, design-based research study resulted in a proposal for a comprehensive set of best instructional practices immersed in a learning trajectory, outlining the tools, processes and the content development for online asynchronous, text-based learning in graduate level professional development courses. The outcome provides a rich…

  17. Using the Community of Inquiry Model to Investigate Students' Knowledge Construction in Asynchronous Online Discussions

    Science.gov (United States)

    Liu, Chien-Jen; Yang, Shu Ching

    2014-01-01

    This study used the Community of Inquiry (CoI) model proposed by Garrison to investigate students' level of knowledge construction in asynchronous discussions. The participants included 36 senior students (27 males) majoring in information management. The students attended 18 weeks of an online information ethics course. In this study, four types…

  18. Electric motor handbook

    CERN Document Server

    Chalmers, B J

    2013-01-01

    Electric Motor Handbook aims to give practical knowledge in a wide range of capacities such as plant design, equipment specification, commissioning, operation and maintenance. The book covers topics such as the modeling of steady-state motor performance; polyphase induction, synchronous, and a.c. commutator motors; ambient conditions, enclosures, cooling and loss dissipation; and electrical supply systems and motor drives. Also covered are topics such as variable-speed drives and motor control; materials and motor components; insulation types, systems, and techniques; and the installation, sit

  19. Directed flux motor

    Science.gov (United States)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  20. Handbook on linear motor application

    International Nuclear Information System (INIS)

    This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.

  1. Fine motor control

    Science.gov (United States)

    ... figure out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination ...

  2. Study on Asynchronous MES Teaching Approach for Discipline of College Japanese in Characteristic Campus of Agriculture-related Universities

    Institute of Scientific and Technical Information of China (English)

    Ming; XU

    2015-01-01

    This paper made scientific analysis on asynchronous MES for discipline of College Japanese in characteristic campus of agriculturerelated universities. It made modular design for discipline of College Japanese in emotional concept,language skill,language knowledge,learning strategy,and cultural quality combining students’ demands and education and teaching rules. Relying on Internet and Mobile Internet aided teaching platform,it came up with " Integration- Separation- Integration" asynchronous teaching approach. The practice indicates that teaching effect of such approach is remarkable. However,asynchronous MES for discipline of College Japanese raises higher requirement for interaction between teachers and students and voluntary effort of teachers.

  3. Edinburgh Motor Assessment (EMAS)

    OpenAIRE

    Bak, Thomas

    2013-01-01

    Edinburgh Motor Assessment (EMAS) is a brief motor screening test, specifically designed for assessment of patients with dementia, aphasia and other cognitive disorders. It focuses, therefore, on those motor symptoms, which are known to occur in association with these diseases, such as extrapyramidal, amyotrophic, and cerebellar features as well as complex cognitive‐motor phenomena such as apraxia. EMAS has been developed by a team of neurologists and psychiatrists at the ...

  4. CONSOLIDATION OF MOTOR MEMORY

    OpenAIRE

    Krakauer, John W.; Shadmehr, Reza

    2005-01-01

    A question of great recent interest is whether motor memory consolidates in a manner analogous to declarative memories, with the formation of a memory that progresses over time from a fragile state, susceptible to interference by a lesion or a conflicting motor task, to a stabilized state, resistant to such interference. Here, we first review studies that examine the anatomical basis for motor consolidation: evidence implicates cerebellar circuitry for two types of associative motor learning,...

  5. Motor Neurons that Multitask

    OpenAIRE

    Goulding, Martyn

    2012-01-01

    Animals use a form of sensory feedback termed proprioception to monitor their body position and modify the motor programs that control movement. In this issue of Neuron, Wen et al. (2012) provide evidence that a subset of motor neurons function as proprioceptors in C. elegans, where B-type motor neurons sense body curvature to control the bending movements that drive forward locomotion.

  6. Quantum motor and future

    CERN Document Server

    Fateev, Evgeny G

    2013-01-01

    In a popular language, the possibilities of the Casimir expulsion effect are presented, which can be the basis of quantum motors. Such motors can be in the form of a special multilayer thin film with periodic and complex nanosized structures. Quantum motors of the type of the Casimir platforms can be the base of transportation, energy and many other systems in the future.

  7. Synchronous and asynchronous multiplexer circuits for medical imaging realized in CMOS 0.18um technology

    Science.gov (United States)

    Długosz, R.; Iniewski, K.

    2007-05-01

    Multiplexers are one of the most important elements in readout front-end ASICs for multi-element detectors in medical imaging. The purpose of these ASICs is to detect signals appearing randomly in many channels and to collect the detected data in an ordered fashion (de-randomization) in order to send it to an external ADC. ASIC output stage functionality can be divided into two: pulse detection and multiplexing. The pulse detection block is responsible for detecting maximum values of signals arriving from the shaper, sending a flag signal indicating that the peak signal has been detected and storing the pulse in an analog memory until read by ADC. The multiplexer in turn is responsible for searching for active flags, controlling the channel that has detected the peak signal and performing reset functions after readout. There are several types of multiplexers proposed in this paper, which can be divided into several classes: synchronous, synchronized and asynchronous. Synchronous circuits require availability of the multiphase clock generator, which increases the power dissipation, but simultaneously provide very convenient mechanism that enables unambiguous choice of the active channel. This characteristics leads to 100% effectiveness in data processing and no data loss. Asynchronous multiplexers do not require clock generators and because of that have simpler structure, are faster and more power efficient, especially when data samples occur seldom at the ASIC's inputs. The main problem of the asynchronous solution is when data on two or more inputs occur almost at the same time, shorter than the multiplexer's reaction time. In this situation some data can be lost. In many applications loss of the order of 1% of the data is acceptable, which makes use of asynchronous multiplexers possible. For applications when the lower loss is desirable a new hierarchy mechanism has been introduced. One of proposed solutions is a synchronized binary tree structure, that uses many

  8. Motor/generator

    Science.gov (United States)

    Hickam, Christopher Dale

    2008-05-13

    A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.

  9. Method for Calculating Performance of Three-Phase Line-Start Permanent-Magnet Synchronous Motor

    Science.gov (United States)

    Takegami, Tsuneo; Tsuboi, Kazuo; Hirotsuka, Isao; Nakamura, Masanori

    A three-phase line-start permanent-magnet synchronous motor (three-phase LSPMM) is expected to operate with ultrahigh efficiency because it can start as an induction motor and can then operate as a permanent-magnet synchronous motor. In a previous study, we developed a practical analytical theory for a three-phase LSPMM on the basis of a tensor analysis. Then, we developed (1) a method for calculating the asynchronous starting characteristics and synchronous operating characteristics of the three-phase LSPMM on the basis of the developed analytical theory and (2) a method for determining the constants of the three-phase LSPMM. Herein, we report the results of a comparison between the calculated and measured asynchronous starting characteristics and synchronous operating characteristics of a test three-phase LSPMM. The comparison results show that the developed calculation method is highly efficient and that the results obtained by using it are sufficiently precise, and therefore, the method is suitable for practical use. Furthermore, we propose a method for improving the starting performance of the three-phase LSPMM, on the basis of simulations performed using the calculation method.

  10. Synchronous and asynchronous electrically evoked motor activities during wind-up stimulation are differentially modulated following an acute spinal transection

    OpenAIRE

    Frigon, Alain; Hurteau, Marie-France; Johnson, Michael D; Heckman, C.J.; Telonio, Alessandro; Thibaudier, Yann

    2012-01-01

    In this study, we used a novel technique to study reflex wind-up when the spinal cord is intact and following an acute spinal transection. Specifically, we evaluated reflex responses evoked by a series of 10 electrical pulses to the tibial or superficial peroneal nerves in 9 decerebrate adult cats, before and after an acute spinal transection. Electromyograms were recorded in four hindlimb muscles (lateral gastrocnemius, tibialis anterior, semitendinosus, and sartorius) to evaluate reflex amp...

  11. Study on the Simulation of the Soft Start of the Asynchronous Motor with Pump Control Function Based on Thyristor

    OpenAIRE

    Tingjian Zhong; Li Zhu; Minghua Zhou; Yongtao Dai

    2009-01-01

  1. Improvable objects and attached dialogue: New literacy practices employed by learners to build knowledge together in asynchronous settings

    OpenAIRE

    Rebecca Ferguson; Denise Whitelock; Karen Littleton

    2010-01-01

    Asynchronous online dialogue offers advantages to learners, but has appeared to involve only limited use of new literacy practices. To investigate this, a multimodal approach was applied to asynchronous dialogue. The study analysed the online discussions of small groups of university students as they developed collaboratively authored documents. Sociocultural discourse analysis of the dialogue was combined with visual analysis of its structural elements. The groups were found to employ new li...

  2. An asynchronous communication system based on the hyperchaotic system of 6th-order cellular neural network

    Science.gov (United States)

    Wang, Xingyuan; Xu, Bing; Luo, Chao

    2012-11-01

    This paper proposes a novel asynchronous communication scheme. Based on this scheme, a model using the hyperchaotic system of 6th-order Cellular Neural Network (CNN) is designed. This scheme enhances the security of asynchronous communication compared to the conventional ones. It is noteworthy that the proposed communication scheme does not depend on synchronization, and almost all chaotic systems can be involved in this scheme. Numerical simulations show the effectiveness of this scheme.

  3. Ventilation Structure Improvement of Induction Motor Using Multiphysics Simulations

    Directory of Open Access Journals (Sweden)

    Xiaowen Wu

    2012-07-01

    Full Text Available Temperature rise analysis has significant impact in the design of air-cooled asynchronous induction motor. However, the affection cannot be accurately evaluated by using traditional empirical curves method due to the complexity of the inductor architecture. Considering Joule’s losses in stator windings and the induced eddy current in squirrel cages, and heat dissipation by air convection and solid conduction, in this paper a 3-D coupled-field finite-element method (FEM is investigated to demonstrate the temperature distribution. The Joule’s losses calculated by 3-D eddy- current field analysis are used as the input for the thermal field analysis, which is deeply dependent on accurate air fluid field analysis. A novel multi-component fluid model is employed to deal with the influence of rotor rotation upon the air convection. The simulation results show the fatal influence of the ventilation structure and the effectiveness of the proposed cooling improvement way.  

  4. Extended ℋ∞ Estimation for Two-Dimensional Markov Jump Systems under Asynchronous Switching

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2013-01-01

    Full Text Available This paper is concerned with the problem of designing ℋ∞ filters for a class of two-dimensional (2D Markov jump systems under asynchronous switching. The problem under consideration is primarily motivated by a realistic situation that the switching of candidate filters may have a lag to the switching of system modes. Different from conventional techniques, by a suitable augmentation, the jumping process of the error system is represented by a two-component Markov chain. Then, the extended transition probabilities are provided for the error system. A stochastic Lyapunov function approach is proposed for the design of desired filters that ensure a prescribed ℋ∞ performance for admissible asynchronous switching. Finally, a numerical example is given to illustrate the effectiveness of the developed method.

  5. The Combine Effect of Synchronous and Asynchronous E-Learning on Distance Education

    Directory of Open Access Journals (Sweden)

    Iqrar Ahmad

    2013-01-01

    Full Text Available The aim of this paper is to highlight the combine effect of synchronous as well as asynchronous in E-learning environment. Both type of learning have importance in different scenario. Not one of them can fulfill whole requirement individually. Synchronous training is done in real-time with a live instructor facilitating the training. Everyone logs in at a set time and can communicate directly with the instructor and with each other. It lasts for a set amount of time - from a single session to several weeks, months or even years. Asynchronous is e-learning in the more traditional sense of the word. It involves self-paced learning, CD-ROM-based, Network-based, Intranet-based or Internet-based. It may include access to instructors through on-line bulletin boards, on-line discussion groups and e-mail.

  6. A Proficient Design of Hybrid Synchronous and Asynchronous Digital FIR Filter using FPGA

    Directory of Open Access Journals (Sweden)

    B.Paulchamy

    2012-07-01

    Full Text Available In this paper, a hybrid synchronous and asynchronous digital FIR filter is designed and implemented in FPGA using VHDL. The digital FIR filter of high throughput, low latency operating at above 1.3 GHz was designed. An adaptive high capacity pipelined was introduced in the hybrid synchronous asynchronous design of the filter. The degree of the pipelining is dynamically variable depending upon the input. Concurrent execution of software or program can be achieved in FPGA through parallel processing. The designed digital FIR filter is simulated using ModelSim and implemented using Xilinx. The simulation results are presented for different order such as 3, 6 and 15. The FIR filter designed is synthesized in Xilinx 9.1i and the device utilization report is presented for filter of order 3, 6 and 15.

  7. Dual stator winding variable speed asynchronous generator: optimal design and experiments

    Science.gov (United States)

    Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

    2015-06-01

    In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA].

  8. Analysis of an FBMC/OQAM scheme for asynchronous access in wireless communications

    Science.gov (United States)

    Mattera, Davide; Tanda, Mario; Bellanger, Maurice

    2015-12-01

    The OFDM/OQAM transceiver belongs to the filter-bank-based multicarrier (FBMC) family and, unlike OFDM schemes, it is particularly able to meet the requirements of the physical layer of cognitive radio networks such as high level of adjacent channel leakage ratio and asynchronous communications. The paper proposes and analyzes a new implementation structure, named frequency spreading, for the OFDM/OQAM transceiver. On flat channels, it is equivalent to the standard one in terms of input-output relations, though more complex. On multipath channels, it offers a crucial advantage in terms of equalization, which is performed in the frequency domain, leading to high performance and no additional delay. With its flexibility and level of performance, the analyzed scheme has the potential to outperform OFDM in the asynchronous access context and in cognitive radio networks.

  9. An Asynchronous Time-Division-Multiplexed Network-on-Chip for Real-Time Systems

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia

    Multi-processor architectures using networks-on-chip (NOCs) for communication are becoming the standard approach in the development of embedded systems and general purpose platforms. Typically, multi-processor platforms follow a globally asynchronous locally synchronous (GALS) timing organization...... important part of the T-CREST paltform and used in a number of configurations. The flexible timing organization of Argo combines asynchronous routers with mesochronous NIs, which are connected to individually clocked cores, supporting a GALS system organization. The mesochronous NIs operate at the same....... This thesis focuses on the design of Argo, a NOC targeted at hard real-time multi-processor platforms with a GALS timing organization. To support real-time communication, NOCs establish end-to-end connections and provide latency and throughput guarantees for these connections. Argo uses time division...

  10. Distributed embedded controller development with petri nets application to globally-asynchronous locally-synchronous systems

    CERN Document Server

    Moutinho, Filipe de Carvalho

    2016-01-01

    This book describes a model-based development approach for globally-asynchronous locally-synchronous distributed embedded controllers.  This approach uses Petri nets as modeling formalism to create platform and network independent models supporting the use of design automation tools.  To support this development approach, the Petri nets class in use is extended with time-domains and asynchronous-channels. The authors’ approach uses models not only providing a better understanding of the distributed controller and improving the communication among the stakeholders, but also to be ready to support the entire lifecycle, including the simulation, the verification (using model-checking tools), the implementation (relying on automatic code generators), and the deployment of the distributed controller into specific platforms. Uses a graphical and intuitive modeling formalism supported by design automation tools; Enables verification, ensuring that the distributed controller was correctly specified; Provides flex...

  11. Exploring effectiveness of team communication: Balancing synchronous and asynchronous communication in design teams

    DEFF Research Database (Denmark)

    den Otter, Ad; Emmitt, Stephen

    2007-01-01

    Effective teams use a balance of synchronous and asynchronous communication. Team communication is dependent on the communication acts of team members and the ability of managers to facilitate, stimulate and motivate them. Team members from organizations using different information systems tend t...... have different understanding, opinions, and rates of adoption and skills levels regarding specific IT tools. The purpose of this paper is to explore the effective use of tools for communication in design teams and the strategies for the use of specific tools.......Effective teams use a balance of synchronous and asynchronous communication. Team communication is dependent on the communication acts of team members and the ability of managers to facilitate, stimulate and motivate them. Team members from organizations using different information systems tend to...

  12. A 0.6-V 8.3-ENOB asynchronous SAR ADC for biomedical applications

    International Nuclear Information System (INIS)

    A microwatt asynchronous successive approximation register (SAR) analog-to-digital converter (ADC) is presented. The supply voltage of the SAR ADC is decreased to 0.6 V to fit the low voltage and low power requirements of biomedical systems. The tail capacitor of the DAC array is reused for least significant bit conversion to decrease the total DAC capacitance thus reducing the power. Asynchronous control logic avoids the high frequency clock generator and further reduces the power consumption. The prototype ADC is fabricated with a standard 0.18 μm CMOS technology. Experimental results show that it achieves an ENOB of 8.3 bit at a 300-kS/s sampling rate. Very low power consumption of 3.04 μW is achieved, resulting in a figure of merit of 32 fJ/conv.-step. (semiconductor integrated circuits)

  13. Realistic modelling of the effects of asynchronous motion at the base of bridge piers

    CERN Document Server

    Romanelli, F; Vaccari, F

    2002-01-01

    Frequently long-span bridges provide deep valley crossings, which require special consideration due to the possibility of local amplification of the ground motion as a consequence of topographical irregularities and local soil conditions. This does in fact cause locally enhanced seismic input with the possibility for the bridge piers to respond asynchronously. This introduces special design requirements so that possible out-of-phase ground displacements and the associated large relative displacements of adjacent piers can be accommodated without excessive damage. Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is thus crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task we compute complete synthetic acc...

  14. Asynchronous update based networked predictive control system using a novel proactive compensation strategy.

    Science.gov (United States)

    Duan, Yingyao; Zuo, Xin; Liu, Jianwei

    2016-01-01

    Networked predictive control system (NPCS) has been proposed to address random delays and data dropouts in networked control systems (NCSs). A remaining challenge of this approach is that the controller has uncertain information about the actual control inputs, which leads to the predicted control input errors. The main contribution of this paper is to develop an explicit mechanism running in the distributed network nodes asynchronously, which enables the controller node to keep informed of the states of the actuator node without a priori knowledge about the network. Based on this mechanism, a novel proactive compensation strategy is proposed to develop asynchronous update based networked predictive control system (AUBNPCS). The stability criterion of AUBNPCS is derived analytically. A simulation experiment based on Truetime demonstrates the effectiveness of the scheme. PMID:26582090

  15. PERFORMANCE ANALYSIS OF GATED RING OSCILLATOR DESIGNED FOR AUDIO FREQUENCY RANGE ASYNCHRONOUS ADC

    Directory of Open Access Journals (Sweden)

    Anita Arvind Deshmukh

    2014-12-01

    Full Text Available This paper presents performance analysis of Gated Ring Oscillator (GRO. Proposed GRO is designed to employ in implementation of Time to Digital Converter (TDC block of Asynchronous ADC. For an audio frequency range ADC, minimum GRO stages are designed using asynchronous technique. So leads to reduced area and power. Compared to conventional Ring Oscillator (RO, we avoided to employ the gated clock; to evade clock design related problems like jitter, additional area and power. Instead we preferred gating of ring oscillator itself. Consequently during sleep mode, GRO disables automatically which saves the dynamic power. Furthermore it also provides first order noise shaping of the quantization and mismatch noise. Proposed GRO is implemented with 0.18µm CMOS Digital Technology in Cadence Virtuso environment. GRO performance analysis shows oscillation frequency as 286 KHz with 327ps jitter and average power consumption of 1.08µW.

  16. Desynchronization of neocortical networks by asynchronous release of GABA at autaptic and synaptic contacts from fast-spiking interneurons.

    Directory of Open Access Journals (Sweden)

    Frédéric Manseau

    Full Text Available Networks of specific inhibitory interneurons regulate principal cell firing in several forms of neocortical activity. Fast-spiking (FS interneurons are potently self-inhibited by GABAergic autaptic transmission, allowing them to precisely control their own firing dynamics and timing. Here we show that in FS interneurons, high-frequency trains of action potentials can generate a delayed and prolonged GABAergic self-inhibition due to sustained asynchronous release at FS-cell autapses. Asynchronous release of GABA is simultaneously recorded in connected pyramidal (P neurons. Asynchronous and synchronous autaptic release show differential presynaptic Ca(2+ sensitivity, suggesting that they rely on different Ca(2+ sensors and/or involve distinct pools of vesicles. In addition, asynchronous release is modulated by the endogenous Ca(2+ buffer parvalbumin. Functionally, asynchronous release decreases FS-cell spike reliability and reduces the ability of P neurons to integrate incoming stimuli into precise firing. Since each FS cell contacts many P neurons, asynchronous release from a single interneuron may desynchronize a large portion of the local network and disrupt cortical information processing.

  17. The Flipped Classroom: A Modality for Mixed Asynchronous and Synchronous Learning in a Residency Program

    OpenAIRE

    Young, Timothy P.; Bailey, Caleb J.; Guptill, Mindi; Thorp, Andrea W.; Thomas, Tamara L

    2014-01-01

    Introduction: A “flipped classroom” educational model exchanges the traditional format of a classroom lecture and homework problem set. We piloted two flipped classroom sessions in our emergency medicine (EM) residency didactic schedule. We aimed to learn about resident and faculty impressions of the sessions, in order to develop them as a regular component of our residency curriculum. Methods: We evaluated residents’ impression of the asynchronous video component and sy...

  18. Punctuated equilibrium in thoroughbred evolution and its model based on asynchronous clocks

    International Nuclear Information System (INIS)

    Evolutionary patterns of thoroughbreds are estimated in terms of distribution of life-spans, avalanche size of extinction and lineage size. All of them show power-law distribution with exponent of -2.0, and show the characteristics of a particular evolutionary pattern called punctuated equilibrium. In addition, we propose a model based on modulation among asynchronous clocks to explain this kind of power-law distribution

  19. Punctuated equilibrium in thoroughbred evolution and its model based on asynchronous clocks

    Energy Technology Data Exchange (ETDEWEB)

    Takachi, Yasuhiro; Gunji, Yukio-Pegio

    2004-02-01

    Evolutionary patterns of thoroughbreds are estimated in terms of distribution of life-spans, avalanche size of extinction and lineage size. All of them show power-law distribution with exponent of -2.0, and show the characteristics of a particular evolutionary pattern called punctuated equilibrium. In addition, we propose a model based on modulation among asynchronous clocks to explain this kind of power-law distribution.

  20. Web-scale Topic Models in Spark: An Asynchronous Parameter Server

    OpenAIRE

    Jagerman, Rolf; Eickhoff, Carsten

    2016-01-01

    In this paper, we train a Latent Dirichlet Allocation (LDA) topic model on the ClueWeb12 data set, a 27-terabyte Web crawl. We extend Spark, a popular framework for performing large-scale data analysis, with an asynchronous parameter server. Such a parameter server provides a distributed and concurrently accessed parameter space for the model. A Metropolis-Hastings based collapsed Gibbs sampler is implemented using this parameter server achieving an amortized O(1) sampling complexity. We comp...

  1. Frequency support among asynchronous AC systems through VSCs emulating power plants

    OpenAIRE

    Papangelis, Lampros; Guillaud, Xavier; Van Cutsem, Thierry

    2015-01-01

    This paper proposes a new control scheme for the Voltage Source Converters (VSCs) of a High Voltage Direct Current (HVDC) grid connecting asynchronous AC systems, so that the latter can mutually support their frequencies after a disturbance. The scheme involves no communication between VSCs. It is activated upon detection of a significant frequency deviation, with the possibility to limit the support requested from other AC systems. It relies on an integral control enforcing the frequency dro...

  2. Synaptotagmin-7 is an asynchronous calcium sensor for synaptic transmission in neurons expressing SNAP-23.

    Directory of Open Access Journals (Sweden)

    Jens P Weber

    Full Text Available Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs. Use of neurons from double-knock-out (SNAP-25, synaptotagmin-7 mice in combination with viral transduction showed that SNAP-23-driven release is triggered by endogenous synaptotagmin-7. In the absence of synaptotagmin-7 release became even more asynchronous, and the spontaneous release rate increased even more, indicating that synaptotagmin-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein pairs SNAP-25/synaptotagmin-1 and SNAP-23/synaptotagmin-7 might act as mutually exclusive calcium sensors. Expression of fusion proteins between pHluorin (pH-sensitive GFP and synaptotagmin-1 or -7 showed that vesicles that fuse using the SNAP-23/synaptotagmin-7 combination contained synaptotagmin-1, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity.

  3. Application of Artificial Intelligence Techniques for the Control of the Asynchronous Machine

    OpenAIRE

    Khammar, F; N. E. Debbache

    2016-01-01

    The induction machine is experiencing a growing success for two decades by gradually replacing the DC machines and synchronous in many industrial applications. This paper is devoted to the study of advanced methods applied to the command of the asynchronous machine in order to obtain a system of control of high performance. While the criteria for response time, overtaking, and static error can be assured by the techniques of conventional control, the criterion of robustness remains a challeng...

  4. Asychronous [i.e. asynchronous] data fusion for AUV navigation using extended Kalman filtering.

    OpenAIRE

    Thorne, Richard L.

    1997-01-01

    A truly Autonomous Vehicle must be able to determine its global position in the absence of external transmitting devices. This requires the optimal integration of all available organic vehicle attitude and velocity sensors. This thesis investigates the extended Kalman filtering method to merge asynchronous heading, heading rate, velocity, and DGPS information to produce a single state vector. Different complexities of Kalman filters, with biases and currents, are investigated with data from F...

  5. S.A.T.E.P. : Synchronous-Asynchronous Tele-education Platform

    OpenAIRE

    Lazaridis, Lazaros; Papatsimouli, Maria; Fragulis, George F.

    2014-01-01

    S.A.T.E.P. means Synchronous Asynchronous Tele education Platform is a software application for educational purposes, with a lot of parametrizing features written entirely from scratch. It aims at the training and examination of computer skills, a platform that can be adjusted to the needs of each lesson. In the application the trainer and the administrator can define the number of the lectures and upload files for each one of them. Furthermore, he can insert, modify and delete questions whic...

  6. Exploiting Synchrony for Area and Performance Improvement in the Asynchronous Domain

    OpenAIRE

    Mahdi Jelodari Mamaghani, Will Toms, Andrew Bardsley, Jim Garside,

    2014-01-01

    This work proposes a synthesis process called ‘eTeak’ which exploits synchronous EDAs to improve the implemented circuits. In this regard, it incorporates the synchronous elastic protocol in the Teak synthesis flow to move fine-grained concurrency from the asynchronous into the synchronous domain where clocked CAD tools can optimise the data manipulation units. A transformation technique is also proposed to enable the designer to explore the level of elasticity in the network and trade off th...

  7. Asynchronous Heterogeneous Mechanism for Hyper-Distributed Hyper-Parallel AI Processing

    Institute of Scientific and Technical Information of China (English)

    SHUAI Dianxun

    1999-01-01

    This paper proposes an asynchronousheterogeneous propagation approach of concurrent competitive waves forhyper-distributed hyper-parallel heuristic problem-solving. Thisapproach is much more powerful than the synchronous homogeneousmechanisms and the asynchronous superimposition algorithms, and hasuniversal validity and availability. The basic conception, concurrentalgorithm and its properties are discussed. The theory and conclusionsdrawn in this paper are of essential importance for the hardwareimplementation of hyper-distributed hyper-parallel processing based onchaotic cellular networks.

  8. Fault simulation and test pattern generation for synchronous and asynchronous sequential circuits

    OpenAIRE

    Lee, Hyung Ki

    1993-01-01

    In this dissertation, we propose two fault simulators, called HOPE and HOPE2, and an autolllatic test pattern generator (ATPG), called ATHENA, for synchronous and asynchronous sequential circuits. HOPE is a parallel fault simulator for synchronous sequential circuits. In HOPE, a packet of 32 faults is simulated in parallel. Several new heuristics are employed in HOPE to accelerate the parallel fault simulation. The heuristics are 1) a reduction of faults to be simulated ...

  9. Structuring asynchronous discussion groups by introducing roles: do students act in line with assigned roles?

    OpenAIRE

    Wever, Bram De; Schellens, Tammy; Van Keer, Hilde; Valcke, Martin

    2008-01-01

    This study focused on the introduction of roles as a scripting tool in asynchronous text-based discussion groups. Five roles were selected: source searcher, theoretician, summarizer, moderator, and starter. Because existing research on role assignment often neglects to check whether the role assignment is successful, the main goal was to examine to what extent the participants enacted assigned roles. The study took place in the 1st year of a university course in Instructional Sciences (N = 20...

  10. Cut Reduction in Linear Logic as Asynchronous Session-Typed Communication

    OpenAIRE

    DeYoung, Henry; Caires, Luís; Pfenning, Frank; Toninho, Bernardo

    2012-01-01

    Prior work has shown that intuitionistic linear logic can be seen as a session-type discipline for the pi-calculus, where cut reduction in the sequent calculus corresponds to synchronous process reduction. In this paper, we exhibit a new process assignment from the asynchronous, polyadic pi-calculus to exactly the same proof rules. Proof-theoretically, the difference between these interpretations can be understood through permutations of inference rules that preserve observ...

  11. Asynchronous and Synchronous Communication in College English Writing in Web-based Learning Environment

    Institute of Scientific and Technical Information of China (English)

    丁洁

    2009-01-01

    In web-based learning environment,College English writing has always been a thorny issue.Here both asynchronous and synchronous communications in college English writing mean the new interactive teaching belief. This paper attempts to do the blending of two in the traditional writing learning and teaching in college English in order to promote a more flexible, efficient and interactive learning environment in accordance with students' interests and needs.

  12. Asynchronous and Synchronous Communication in College English Writing in Web-based Learning Environment

    Institute of Scientific and Technical Information of China (English)

    丁洁

    2009-01-01

    In web-based learning environment,College English writing has always been a thorny issue.Here both asynchronous and synchronous communications in college English writing mean the new interactive teaching belief. This paper attempts to do the blending of two in the traditional writing learning and teaching in college English in order to promote a more flexible,efficient and interactive learning environment in accordance with students' interests and needs.

  13. Using Team-Based Learning in an Online, Asynchronous Information Literacy Course

    OpenAIRE

    Allison Hosier

    2013-01-01

    Making information literacy instruction engaging to learners can be a challenge. Making it engaging in an online, asynchronous setting can be even more daunting. As students seek more opportunities for online learning, it’s becoming increasingly important to develop information literacy instruction that will promote engagement and enhance learning in the online environment. Team-Based Learning is a method of instruction that has transformed the atmosphere of a face-to-face information literac...

  14. Propagation of external regulation and asynchronous dynamics in random Boolean networks

    OpenAIRE

    Mahmoudi, Hamed; Pagnani, Andrea; Weigt, Martin; Zecchina, Riccardo

    2007-01-01

    Boolean Networks and their dynamics are of great interest as abstract modeling schemes in various disciplines, ranging from biology to computer science. Whereas parallel update schemes have been studied extensively in past years, the level of understanding of asynchronous updates schemes is still very poor. In this paper we study the propagation of external information given by regulatory input variables into a random Boolean network. We compute both analytically and numerically the time evol...

  15. Asynchronous accelerator with RFQ injection for active longitudinal compression of accelerated bunches

    OpenAIRE

    Tumanyan, A. R.; Martirosyan, Yu. L.; Nikhogosyan, V. C.; Akopov, N. Z.; Guiragossian, Z. G.; Martirosov, R. M.; Akopov, Z. N.

    2000-01-01

    An asynchronous accelerator is described, in which the principle of its operation permits the active longitudinal bunch compression of accelerated proton beams, to overcome the space charge limitation effects of intense bunches. It is shown that accelerated bunches from an RFQ linac can be adapted for Asynchronac injection for a multiple of choices in the acceleration frequencies of the RFQ and the Asynchronac. The offered new type of accelerator system is especially suitable to accelerate pr...

  16. Performance of asynchronous orthogonal multicarrier CDMA system in frequency selective fading channel

    OpenAIRE

    Xiang, G; Ng, TS

    1999-01-01

    An asynchronous multicarrier (MC) direct-sequence (DS) code-division multiple-access (CDMA) scheme for the uplink of the mobile communication system operating in a frequency selective fading channel is analyzed. Bit error rate performance of the system with either equal-gain combining or maximum-ratio combining is obtained. Numerical results indicate that the system performs better than that of the conventional DS-CDMA system and another MC-DS-CDMA system.

  17. Asynchronous local dynamics contributes to stability of a seagrass bed in Tokyo Bay

    OpenAIRE

    Yamakita, Takehisa; Watanabe,Kentaro; Nakaoka, Masahiro

    2011-01-01

    It is known that asynchronous temporal variations in local populations can contribute to the stability of metapopulations. However, studies evaluating the hierarchical organization of multiple spatial scales are rare for continuous marine landscapes, especially for marine vegetation such as seagrass beds. In this study, long-term observation (26 years) of temporal changes and nested spatial analyses were combined for an extensive seagrass meadow in Tokyo Bay, Japan, using remote sensing and g...

  18. A Leader Election Protocol for Fault Recovery in Asynchronous Fully-Connected Networks

    OpenAIRE

    Franceschetti, Massimo; Bruck, Jehoshua

    1998-01-01

    We introduce a new algorithm for consistent failure detection in asynchronous systems. Informally, consistent failure detection requires processes in a distributed system to distinguish between two different populations: a fault free population and a faulty one. The major contribution of this paper is in combining ideas from group membership and leader election, in order to have an election protocol for a fault manager whose convergence is delayed until a new consistent view ...

  19. Critical thinking in asynchronous online discussions: examining the role of the student facilitator

    OpenAIRE

    Hew, KF; Cheung, WS; Jumain, SN

    2010-01-01

    This paper is part of a larger study that investigates the types of facilitation techniques exhibited by student facilitators and how these techniques may foster in-depth levels of critical thinking in asynchronous online discussions. Data were collected from ten discussion forums, involving education major students. The top 30% of forums in terms of the most number of in-depth critical thinking incidences were first identified (i.e., higher-level group). Next, the bottom 30% forums were iden...

  20. Research of methods of providing of temporal transparency of asynchronous TK network

    OpenAIRE

    Нашат, Галеб Саммур Альбдур

    2011-01-01

    Work is devoted development and research of new methods of indemnification of jittera by the additional delay of barns in the buffer of knot of commutation at the different levels of his load for providing of sentinel transparency of asynchronous telecommunication networks. The method of calculation of indexes of sentinel transparency of network is offered, which takes into account necessary quality of service traffic and allows to forecast the mean value of delay an...

  1. Asynchronous telepsychiatry in Maharashtra, India: Study of feasibility and referral pattern

    OpenAIRE

    Vanshree Patil Balasinorwala; Shah, Nilesh B.; Chatterjee, Soumya D.; Kale, Vinayak P.; Yusuf A Matcheswalla

    2014-01-01

    Context: There is a paucity of published telepsychiatry results in India. Aims: This study was conducted to assess the feasibility of asynchronous telepsychiatry and to study the referral patterns. Settings and Design: This study was conducted in the telemedicine unit of a tertiary care center and design was retrospective analysis of 94 cases, which were diagnosed and treated by telepsychiatry. Materials and Methods: All 94 patients who were referred between January 2007 and August 2013 for t...

  2. Application of Asynchronous Weak Commitment Search in Autonomous Quality of Service Provision in Cognitive Radio Networks

    OpenAIRE

    Sodagari, Shabnam

    2014-01-01

    This article presents a distributed solution to autonomous quality of service provision in cognitive radio networks. Specifically, cognitive STDMA and CDMA communication networks are studied. Based on asynchronous weak commitment search the task of QoS provision is distributed among different network nodes. Simulation results verify this scheme converges very fast to optimal solution, which makes it suitable for practical real time systems. This application of artificial intelligence in wirel...

  3. Asynchronous replication and autosome-pair non-equivalence in human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Devkanya Dutta

    Full Text Available A number of mammalian genes exhibit the unusual properties of random monoallelic expression and random asynchronous replication. Such exceptional genes include genes subject to X inactivation and autosomal genes including odorant receptors, immunoglobulins, interleukins, pheromone receptors, and p120 catenin. In differentiated cells, random asynchronous replication of interspersed autosomal genes is coordinated at the whole chromosome level, indicative of chromosome-pair non-equivalence. Here we have investigated the replication pattern of the random asynchronously replicating genes in undifferentiated human embryonic stem cells, using fluorescence in situ hybridization based assay. We show that allele-specific replication of X-linked genes and random monoallelic autosomal genes occur in human embryonic stem cells. The direction of replication is coordinated at the whole chromosome level and can cross the centromere, indicating the existence of autosome-pair non-equivalence in human embryonic stem cells. These results suggest that epigenetic mechanism(s that randomly distinguish between two parental alleles are emerging in the cells of the inner cell mass, the source of human embryonic stem cells.

  4. Synchronous and Asynchronous E-Language Learning: A Case Study of Virtual University of Pakistan

    Directory of Open Access Journals (Sweden)

    Ayesha Perveen

    2016-03-01

    Full Text Available This case study evaluated the impact of synchronous and asynchronous E-Language Learning activities (ELL-tivities in an E-Language Learning Environment (ELLE at Virtual University of Pakistan. The purpose of the study was to assess e-language learning analytics based on the constructivist approach of collaborative construction of knowledge. The courses selected for random sampling were English Comprehension (Eng101, Business & Technical English (Eng201 and Business Communication (Eng301. Three methods were employed to collect the data: observation of the communication and performance on given channels, students’ opinions on Graded Discussion Board (GDB, and a survey questionnaire. Out of a total population of 9919, 1025 responses were received for the survey questionnaire. The findings revealed that asynchronous e-language learning was quite beneficial for second language (L2 learners, but with some limitations which could be scaffolded by synchronous sessions. Based on the findings, the researcher suggested a blend of both synchronous and asynchronous paradigms to create an ideal environment for e-language learning in Pakistan.

  5. A modular control architecture for real-time synchronous and asynchronous systems

    International Nuclear Information System (INIS)

    This paper describes a control architecture for real-time control of complex robotic systems. The Modular Integrated Control Architecture (MICA), which is actually two complementary control systems, recognizes and exploits the differences between asynchronous and synchronous control. The asynchronous control system simulates shared memory on a heterogeneous network. For control information, a portable event-scheme is used. This scheme provides consistent interprocess coordination among multiple tasks on a number of distributed systems. The machines in the network can vary with respect to their native operating systems and the intemal representation of numbers they use. The synchronous control system is needed for tight real-time control of complex electromechanical systems such as robot manipulators, and the system uses multiple processors at a specified rate. Both the synchronous and asynchronous portions of MICA have been developed to be extremely modular. MICA presents a simple programming model to code developers and also considers the needs of system integrators and maintainers. MICA has been used successfully in a complex robotics project involving a mobile 7-degree-of-freedom manipulator in a heterogeneous network with a body of software totaling over 100,000 lines of code. MICA has also been used in another robotics system, controlling a commercial long-reach manipulator

  6. Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach †

    Science.gov (United States)

    Zhu, Weiping; Chen, Weiran; Hu, Zhejie; Li, Zuoyou; Liang, Yue; Chen, Jiaojiao

    2016-01-01

    Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption. PMID:27058544

  7. Low Power Analysis of Network-Level On-chip communication using Asynchronous AMBA protocol

    Directory of Open Access Journals (Sweden)

    E. Sakthivel

    2012-07-01

    Full Text Available Network on-chip (NoC is a novel structuraldesign template, which can be defied for complicatedsystem level on-chip design. NoC has a potential tolimit and present the bus-based communication. In thispaper, the crisis to discuss is Low power consumptionin an Asynchronous Network on-chip (NoC levelcommunication. NoC is implemented using FPGAwhich has less fabrication cost and reduces thecomplexity. An Asynchronous NoC has beenimplemented in Spartan kit using Xilinx FPGA ISEtools and its network interface is AdvancedMicrocontroller Bus Architecture (AMBA whichfeatures numerous bus masters and a sole clock edgeevolution and so on. Here the AMBA highperformance 32-bit AHB bus is employed in which ithas a high clock frequency system and it is the heart ofour bus system. To accomplish low power consumptionby interfacing SoC with AMBA- AHB protocol. TheAHB model and an Asynchronous NoC are employedand executed using VHDL programming module

  8. An FDES-Based Shared Control Method for Asynchronous Brain-Actuated Robot.

    Science.gov (United States)

    Liu, Rong; Wang, Yong-Xuan; Zhang, Lin

    2016-06-01

    The asynchronous brain-computer interface (BCI) offers more natural human-machine interaction. However, it is still considered insufficient to control rapid and complex sequences of movements for a robot without any advanced control method. This paper proposes a new shared controller based on the supervisory theory of fuzzy discrete event system (FDES) for brain-actuated robot control. The developed supervisory theory allows the more reliable control mode to play a dominant role in the robot control which is beneficial to reduce misoperation and improve the robustness of the system. The experimental procedures consist of real-time direct manual control and BCI control tests from ten volunteers. Both tests have shown that the proposed method significantly improves the performance and robustness of the robotic control. In an online BCI experiment, eight of the participants successfully controlled the robot to circumnavigate obstacles and reached the target with a three mental states asynchronous BCI while the other two participants failed in all the BCI control sessions. Furthermore, the FDES-based shared control method also helps to reduce the workload. It can be stated that the asynchronous BCI, in combination with FDES-based shared controller, is feasible for the real-time and robust control of robotics. PMID:26357416

  9. Rational Secret Sharing over an Asynchronous Broadcast Channel with Information Theoretic Security

    CERN Document Server

    Moses, William K; 10.5121/ijnsa.2011.3601

    2011-01-01

    We consider the problem of rational secret sharing introduced by Halpern and Teague [1], where the players involved in secret sharing play only if it is to their advantage. This can be characterized in the form of preferences. Players would prefer to get the secret than to not get it and secondly with lesser preference, they would like as few other players to get the secret as possible. Several positive results have already been published to efficiently solve the problem of rational secret sharing but only a handful of papers have touched upon the use of an asynchronous broadcast channel. [2] used cryptographic primitives, [3] used an interactive dealer, and [4] used an honest minority of players in order to handle an asynchronous broadcast channel. In our paper, we propose an m-out-of-n rational secret sharing scheme which can function over an asynchronous broadcast channel without the use of cryptographic primitives and with a non-interactive dealer. This is possible because our scheme uses a small number, ...

  10. An asynchronous multi-sensor micro control unit for wireless body sensor networks (WBSNs).

    Science.gov (United States)

    Chen, Chiung-An; Chen, Shih-Lun; Huang, Hong-Yi; Luo, Ching-Hsing

    2011-01-01

    In this work, an asynchronous multi-sensor micro control unit (MCU) core is proposed for wireless body sensor networks (WBSNs). It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE), and an error correct coder (ECC). To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs. PMID:22164000

  11. INVESTIGATING THE EFFECT OF ASYNCHRONOUS DISCUSSIONS ON STUDENTS’ LEARNING AND UNDERSTANDING OF MATHEMATICS SUBJECT

    Directory of Open Access Journals (Sweden)

    Ozcan OZYURT

    2011-10-01

    Full Text Available Recently, learning activities have gone beyond conventional environments and started to be performed via computer supported instruments. One of these instruments is asynchronous discussion forums (ADFs used as computer-supported collaborative learning means. Learners practice various learning activities in ADFs and produce knowledge construction. In the present study, document analysis was employed and all Turkish originated ADFs relating mathematics teaching were scanned and put subjected to content analysis. Besides, a survey was implemented on 86 high school and undergraduate students. Both qualitative and quantitative data were obtained through this survey. These data were put subjected to qualitative and quantitative data analysis. Attitudes of students towards computer-supported collaborative learning and asynchronous discussion forums as mathematics learning instrument were tried to be revealed via this study. Also, behaviors of the learners and their views relating the learning activities in these environments were evaluated by means of this study. Results of the study demonstrated that asynchronous discussion forums are widely and efficiently used as computer-supported collaborative learning instrument in terms of mathematics learning.

  12. Asynchronous data change notification between database server and accelerator controls system

    International Nuclear Information System (INIS)

    Database data change notification (DCN) is a commonly used feature. Not all database management systems (DBMS) provide an explicit DCN mechanism. Even for those DBMS's which support DCN (such as Oracle and MS SQL server), some server side and/or client side programming may be required to make the DCN system work. This makes the setup of DCN between database server and interested clients tedious and time consuming. In accelerator control systems, there are many well established software client/server architectures (such as CDEV, EPICS, and ADO) that can be used to implement data reflection servers that transfer data asynchronously to any client using the standard SET/GET API. This paper describes a method for using such a data reflection server to set up asynchronous DCN (ADCN) between a DBMS and clients. This method works well for all DBMS systems which provide database trigger functionality. Asynchronous data change notification (ADCN) between database server and clients can be realized by combining the use of a database trigger mechanism, which is supported by major DBMS systems, with server processes that use client/server software architectures that are familiar in the accelerator controls community (such as EPICS, CDEV or ADO). This approach makes the ADCN system easy to set up and integrate into an accelerator controls system. Several ADCN systems have been set up and used in the RHIC-AGS controls system.

  13. Self-calibration algorithm in an asynchronous P300-based brain-computer interface

    Science.gov (United States)

    Schettini, F.; Aloise, F.; Aricò, P.; Salinari, S.; Mattia, D.; Cincotti, F.

    2014-06-01

    Objective. Reliability is a desirable characteristic of brain-computer interface (BCI) systems when they are intended to be used under non-experimental operating conditions. In addition, their overall usability is influenced by the complex and frequent procedures that are required for configuration and calibration. Earlier studies examined the issue of asynchronous control in P300-based BCIs, introducing dynamic stopping and automatic control suspension features. This report proposes and evaluates an algorithm for the automatic recalibration of the classifier's parameters using unsupervised data. Approach. Ten healthy subjects participated in five P300-based BCI sessions throughout a single day. First, we examined whether continuous adaptation of control parameters improved the accuracy of the asynchronous system over time. Then, we assessed the performance of the self-calibration algorithm with respect to the no-recalibration and supervised calibration conditions with regard to system accuracy and communication efficiency. Main results. Offline tests demonstrated that continuous adaptation of the control parameters significantly increased the communication efficiency of asynchronous P300-based BCIs. The self-calibration algorithm correctly assigned labels to unsupervised data with 95% accuracy, effecting communication efficiency that was comparable with that of supervised repeated calibration. Significance. Although additional online tests that involve end-users under non-experimental conditions are needed, these preliminary results are encouraging, from which we conclude that the self-calibration algorithm is a promising solution to improve P300-based BCI usability and reliability.

  14. AP-IO: Asynchronous Pipeline I/O for Hiding Periodic Output Cost in CFD Simulation

    Directory of Open Access Journals (Sweden)

    Ren Xiaoguang

    2014-01-01

    Full Text Available Computational fluid dynamics (CFD simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%.

  15. AP-IO: asynchronous pipeline I/O for hiding periodic output cost in CFD simulation.

    Science.gov (United States)

    Xiaoguang, Ren; Xinhai, Xu

    2014-01-01

    Computational fluid dynamics (CFD) simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO) optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%. PMID:24955390

  16. Identifying scale-emergent, nonlinear, asynchronous processes of wetland methane exchange

    Science.gov (United States)

    Sturtevant, Cove; Ruddell, Benjamin L.; Knox, Sara Helen; Verfaillie, Joseph; Matthes, Jaclyn Hatala; Oikawa, Patricia Y.; Baldocchi, Dennis

    2016-01-01

    Methane (CH4) exchange in wetlands is complex, involving nonlinear asynchronous processes across diverse time scales. These processes and time scales are poorly characterized at the whole-ecosystem level, yet are crucial for accurate representation of CH4 exchange in process models. We used a combination of wavelet analysis and information theory to analyze interactions between whole-ecosystem CH4 flux and biophysical drivers in two restored wetlands of Northern California from hourly to seasonal time scales, explicitly questioning assumptions of linear, synchronous, single-scale analysis. Although seasonal variability in CH4 exchange was dominantly and synchronously controlled by soil temperature, water table fluctuations, and plant activity were important synchronous and asynchronous controls at shorter time scales that propagated to the seasonal scale. Intermittent, subsurface water table decline promoted short-term pulses of methane emission but ultimately decreased seasonal CH4 emission through subsequent inhibition after rewetting. Methane efflux also shared information with evapotranspiration from hourly to multiday scales and the strength and timing of hourly and diel interactions suggested the strong importance of internal gas transport in regulating short-term emission. Traditional linear correlation analysis was generally capable of capturing the major diel and seasonal relationships, but mesoscale, asynchronous interactions and nonlinear, cross-scale effects were unresolved yet important for a deeper understanding of methane flux dynamics. We encourage wider use of these methods to aid interpretation and modeling of long-term continuous measurements of trace gas and energy exchange.

  17. An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs

    Directory of Open Access Journals (Sweden)

    Ching-Hsing Luo

    2011-07-01

    Full Text Available In this work, an asynchronous multi-sensor micro control unit (MCU core is proposed for wireless body sensor networks (WBSNs. It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE, and an error correct coder (ECC. To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs.

  18. Two-Particle Asynchronous Quantum Correlation: Wavefunction Collapse Acting as a Beamsplitter

    Science.gov (United States)

    Kowalski, F. V.; Browne, R. S.

    2016-03-01

    A two-body quantum correlation is calculated for a particle reflecting from a moving mirror. Correlated interference results when the incident and reflected particle substates and their associated mirror substates overlap. Using the Copenhagen interpretation of measurement, an asynchronous joint probability density (PDF), which is a function both of the different positions and different times at which the particle and mirror are measured, is derived assuming that no interaction occurs between each measurement. Measurement of the particle first, in the correlated interference region, results in a splitting of the mirror substate into ones which have and have not reflected the particle. An analog of the interference from the Doppler effect for only measurements of the particle (a marginal PDF), in this two-body system, is shown to be a consequence of the asynchronous measurement. The simplification obtained for a microscopic particle reflecting from a mesoscopic or macroscopic mirror is used to illustrate asynchronous correlation interferometry. In this case, the small displacement between these mirror states can yield negligible environmental decoherence times. In addition, interference of these mirror states does not vanish in the limit of large mirror mass due to the small momentum exchange in reflecting a microscopic particle.

  19. Designing a WISHBONE Protocol Network Adapter for an Asynchronous Network-on-Chip

    Directory of Open Access Journals (Sweden)

    Ahmed H M Soliman

    2011-07-01

    Full Text Available The Scaling of microchip technologies, from micron to submicron and now to deep sub-micron (DSM range, has enabled large scale systems-on-chip (SoC. In future deep submicron (DSM designs, the interconnect effect will definitely dominate performance. Network-on-Chip (NoC has become a promising solution to bus-based communication infrastructure limitations. NoC designs usually targets Application Specific Integrated Circuits (ASICs, however, the fabrication process costs a lot. Implementing a NoC on an FPGA does not only reduce the cost but also decreases programming and verification cycles. In this paper, an Asynchronous NoC has been implemented on a SPARTAN-3Eandamp;reg; device. The NoC supports basic transactions of both widely used on-chip interconnection standards, the Open Core Protocol (OCP and the WISHBONE Protocol. Although, FPGA devices are synchronous in nature, it has been shown that they can be used to prototype a Global Asynchronous Local Synchronous (GALS systems, comprising an Asynchronous NoC connecting IP cores operating in different clock domains.

  20. A full asynchronous serial transmission converter for network-on-chips

    International Nuclear Information System (INIS)

    Large transmission power consumptions and excessive interconnection lines are two shortcomings which exist in conventional network-on-chips. To improve performance in these areas, this paper proposes a full asynchronous serial transmission converter for network-on-chips. By grouping the parallel data between routers into smaller data blocks, interconnection lines between routers can be greatly reduced, which finally brings about saving of power overheads in the transmission process. Null convention logic units are used to make the circuit quasi-delay insensitive and highly robust. The proposed serial transmission converter and serial channel are implemented based on SMIC 0.18 μm standard CMOS technology. Results demonstrate that this full asynchronous serial transmission converter can save up to three quarters of the interconnection line resources and also reduce up to two-thirds of the power consumption under 32 bit data widths. The proposed full asynchronous serial transmission converter can apply to the on chip network which is sensitive to area and power. (semiconductor integrated circuits)

  1. Neuroplasticity & Motor Learning

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye

    the other hand the changes underlie the formation of motor memory and the retention of improved motor performance. During motor learning changes may occur at many different levels within the central nervous system dependent on the type of task and training. Here, we demonstrate different studies from...... measure of our ability to form and store a motor memory of the task. However, the initial memory of the task is labile and may be subject to interference. During and following motor learning plastic changes occur within the central nervous system. On one hand these changes are driven by motor practice, on...... our research group which aim at elucidating how different types of training (and disuse) may be accompanied by changes in behaviour as well as cortical representational maps and excitability, corticospinal drive and corticomuscular coherence, spinal reflex parameters etc....

  2. Motor degradation prediction methods

    International Nuclear Information System (INIS)

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures

  3. Analysis and control of excitation, field weakening and stability in direct torque controlled electrically excited synchronous motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Pyrhoenen, O.

    1998-12-31

    Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor`s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque

  4. Motor Axon Pathfinding

    OpenAIRE

    Bonanomi, Dario; Pfaff, Samuel L

    2010-01-01

    Motor neurons are functionally related, but represent a diverse collection of cells that show strict preferences for specific axon pathways during embryonic development. In this article, we describe the ligands and receptors that guide motor axons as they extend toward their peripheral muscle targets. Motor neurons share similar guidance molecules with many other neuronal types, thus one challenge in the field of axon guidance has been to understand how the vast complexity of brain connection...

  5. Cryogenic Electric Motor Tested

    Science.gov (United States)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  6. Control motor brushless sensorless

    OpenAIRE

    Solchaga Pérez de Lazárraga, Gonzalo

    2015-01-01

    El proyecto consiste en la creación de un circuito capaz de controlar la velocidad de un motor brushless sensorless. Este tipo de motores eléctricos tienen como característica que no tienen escobillas para cambiar la polaridad del bobinado de su interior y tampoco precisan de un sensor que indique que ha realizado una vuelta. Los motores brushless que son controlados por este tipo de circuitos son específicos para aeronaves no tripuladas y requieren un diseño diferente a un motor brushless pe...

  7. Are my motors oversized?

    International Nuclear Information System (INIS)

    Three-phase induction motors accounts with an important share of the electricity consumption in industrialized countries. Therefore, the misapplication of such machines conducts to efficiency reduction and large amounts of energy waste. Motor oversize is one of the most frequently misapplication encountered and difficult to be fixed. The paper presents a road map to evaluate whether a direct line fed three-phase induction motor is oversized, considering not only its steady loading, but also its dynamic behavior. In addition, case studies are presented and some solutions to increase the energy efficiency of the whole motor-load system are proposed.

  8. Open loop thanks to direct torque control (DTC). Motor control without feedback loop; Open loop dank direkter Drehmomentregelung (DTC). Hochwertige Motorregelung ohne Rueckfuehrung

    Energy Technology Data Exchange (ETDEWEB)

    Link, Michael [ABB Automation Products GmbH, Ladenburg (Germany)

    2009-07-01

    Servo drives are used in various applications. The range of applications is huge and thus also requirements to the drive system. Mainly, a fast torque and speed control is required. This is the domaine of direct torque control (DTC). In many applications DTC can meet this challenge to control the motor with full torque at zero speed. The servo converter based on DTC technology provides a control concept for synchronous and asynchronous motors for both closed loop and open loop control. DTC controlled drives support the whole range from open loop up to high performance motion control applications. (orig.)

  9. Energy efficient electric drives. Fundamentals, power electronics, operational behaviour and regulation of the three-phase motor; Energieeffiziente elektrische Antriebe. Grundlagen, Leistungselektronik, Betriebsverhalten und Regelung von Drehstrommotoren

    Energy Technology Data Exchange (ETDEWEB)

    Teigelkoetter, Johannes [Hochschule Aschaffenburg (Germany)

    2013-02-01

    An efficient utilization of electric power in the electric drive technology is necessary because nearly two thirds of the generated electric power is consumed. The textbook under consideration reports on the technical fundamentals and methods for the increase of energy efficiency in the electric drive technology. Especially, a detailed understanding of modern drives with asynchronous motors as well as synchronous motors is enabled by a thorough introduction to the space-vector calculation. In addition to electrical machines, also the handling procedures for pulse inverters, control methods and sensors for electrical drives are described. Each chapter concludes with calculated exercises in order to deepen the content of teaching.

  10. Analysis and control of excitation, field weakening and stability in direct torque controlled electrically excited synchronous motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Pyrhoenen, O.

    1998-01-01

    Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor's electromagnetic state and load. The load angle can be limited indirectly by limiting the

  11. MISR Motor Data V003

    Data.gov (United States)

    National Aeronautics and Space Administration — This file contains the output for the Level 1A Motor data (Suggested Usage: MISR SCF processing needs the MISR motor data samples for the analysis of motor...

  12. Organizing motor imageries.

    Science.gov (United States)

    Hanakawa, Takashi

    2016-03-01

    Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980

  13. Operation of a general purpose stepping motor-encoder positioning subsystem at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Four copies of a general purpose subsystem for mechanical positioning of detectors, samples, and beam line optical elements which constitute experiments at the National Synchrotron Light Source facility of Brookhaven National Laboratory have been constructed and placed into operation. Construction of a fifth subsystem unit is nearing completion. The subsystems affect mechanical positioning by controlling a set of stepping motor-encoder pairs. The units are general purpose in the sense that they receive commands over a 9600 baud asynchronous serial line compatible with the RS-232-C electrical signal standard, generate TTL-compatible streams of stepping pulses which can be used with a wide variety of stepping motors, and read back position values from a number of different types and models of position encoder. The basic structure of the motor controller subsystem is briefly reviewed. Additions to the subsystem made in response to problems indicated by actual operation of the four installed units are described in more detail

  14. Similar brain networks for detecting visuo-motor and visuo-propriceptive synchrony

    DEFF Research Database (Denmark)

    Balslev, Daniela; Nielsen, Finn Årup; Lund, Torben Ellegaard;

    2006-01-01

    The ability to recognize feedback from own movement as opposed to the movement of someone else is important for motor control and social interaction. The neural processes involved in feedback recognition are incompletely understood. Two competing hypotheses have been proposed: the stimulus is...... compared with either (a) the proprioceptive feedback or with (b) the motor command and if they match, then the external stimulus is identified as feedback. Hypothesis (a) predicts that the neural mechanisms or brain areas involved in distinguishing self from other during passive and active movement are...... the visual stimulus was feedback from own movement and to contrast the functional activation maps for active and passive movement. We found activity increases in the right temporoparietal cortex in the condition with asynchronous relative to synchronous visual feedback from both active and passive...

  15. Similar brain networks for detecting visuo-motor and visuo-proprioceptive synchrony

    DEFF Research Database (Denmark)

    Balslev, Daniela; Nielsen, Finn Å; Ellegaard Lund, Torben;

    2006-01-01

    The ability to recognize feedback from own movement as opposed to the movement of someone else is important for motor control and social interaction. The neural processes involved in feedback recognition are incompletely understood. Two competing hypotheses have been proposed: the stimulus is...... compared with either (a) the proprioceptive feedback or with (b) the motor command and if they match, then the external stimulus is identified as feedback. Hypothesis (a) predicts that the neural mechanisms or brain areas involved in distinguishing self from other during passive and active movement are...... the visual stimulus was feedback from own movement and to contrast the functional activation maps for active and passive movement. We found activity increases in the right temporoparietal cortex in the condition with asynchronous relative to synchronous visual feedback from both active and passive...

  16. Dynamic wheelset drive load of the railway vehicle caused by short-circuit motor moment

    Directory of Open Access Journals (Sweden)

    Zeman V.

    2009-12-01

    Full Text Available The paper deals with mathematical modelling of dynamic response of the railway vehicle wheelset drives caused by short-circuit traction motor torque. The individual wheelset drive with hollow graduated shaft is one of subsystems of the two-axled vehicle bogie with two wheelset drives. The model respects the viscoelastic suspension of the both engine stators with gear housings mounted on the bogie frame and all the other couplings among bogie drive components. The dynamic response is investigated in dependence on longitudinal creepage and forward velocity of the vehicle at the moment of the sudden short-circuit in one asynchronous traction motor. The method is applied to bogie of the electric locomotive developed for speed about 200 km/h by the company ŠKODA TRANSPORTATION, s. r. o. The wheelset drive vibration is confronted with stability conditions of the whole bogie.

  17. Asynchronous response of tropical forest leaf phenology to seasonal and el Nino-driven drought.

    Directory of Open Access Journals (Sweden)

    Stephanie Pau

    Full Text Available The Hawaiian Islands are an ideal location to study the response of tropical forests to climate variability because of their extreme isolation in the middle of the Pacific, which makes them especially sensitive to El Niño-Southern Oscillation (ENSO. Most research examining the response of tropical forests to drought or El Niño have focused on rainforests, however, tropical dry forests cover a large area of the tropics and may respond very differently than rainforests. We use satellite-derived Normalized Difference Vegetation Index (NDVI from February 2000-February 2009 to show that rainforests and dry forests in the Hawaiian Islands exhibit asynchronous responses in leaf phenology to seasonal and El Niño-driven drought. Dry forest NDVI was more tightly coupled with precipitation compared to rainforest NDVI. Rainforest cloud frequency was negatively correlated with the degree of asynchronicity (Delta(NDVI between forest types, most strongly at a 1-month lag. Rainforest green-up and dry forest brown-down was particularly apparent during the 2002-003 El Niño. The spatial pattern of NDVI response to the NINO 3.4 Sea Surface Temperature (SST index during 2002-2003 showed that the leeward side exhibited significant negative correlations to increased SSTs, whereas the windward side exhibited significant positive correlations to increased SSTs, most evident at an 8 to 9-month lag. This study demonstrates that different tropical forest types exhibit asynchronous responses to seasonal and El Niño-driven drought, and suggests that mechanisms controlling dry forest leaf phenology are related to water-limitation, whereas rainforests are more light-limited.

  18. XMPP for cloud computing in bioinformatics supporting discovery and invocation of asynchronous web services

    Directory of Open Access Journals (Sweden)

    Willighagen Egon L

    2009-09-01

    Full Text Available Abstract Background Life sciences make heavily use of the web for both data provision and analysis. However, the increasing amount of available data and the diversity of analysis tools call for machine accessible interfaces in order to be effective. HTTP-based Web service technologies, like the Simple Object Access Protocol (SOAP and REpresentational State Transfer (REST services, are today the most common technologies for this in bioinformatics. However, these methods have severe drawbacks, including lack of discoverability, and the inability for services to send status notifications. Several complementary workarounds have been proposed, but the results are ad-hoc solutions of varying quality that can be difficult to use. Results We present a novel approach based on the open standard Extensible Messaging and Presence Protocol (XMPP, consisting of an extension (IO Data to comprise discovery, asynchronous invocation, and definition of data types in the service. That XMPP cloud services are capable of asynchronous communication implies that clients do not have to poll repetitively for status, but the service sends the results back to the client upon completion. Implementations for Bioclipse and Taverna are presented, as are various XMPP cloud services in bio- and cheminformatics. Conclusion XMPP with its extensions is a powerful protocol for cloud services that demonstrate several advantages over traditional HTTP-based Web services: 1 services are discoverable without the need of an external registry, 2 asynchronous invocation eliminates the need for ad-hoc solutions like polling, and 3 input and output types defined in the service allows for generation of clients on the fly without the need of an external semantics description. The many advantages over existing technologies make XMPP a highly interesting candidate for next generation online services in bioinformatics.

  19. Rational Secret Sharing Over an Asynchronous Broadcast Channel With Information Theoretic Security

    Directory of Open Access Journals (Sweden)

    William K. Moses Jr.

    2011-12-01

    Full Text Available We consider the problem of rational secret sharing introduced by Halpern and Teague [1], where the players involved in secret sharing play only if it is to their advantage. This can be characterized in the form of preferences. Players would prefer to get the secret than to not get it and secondly with lesser preference, they would like as few other players to get the secret as possible. Several positive results have already been published to efficiently solve the problem of rational secret sharing but only a handful of papers have touched upon the use of an asynchronous broadcast channel. [2] used cryptographic primitives, [3] used an interactive dealer, and [4] used an honest minority of players in order to handle an asynchronous broadcast channel. In our paper, we propose an m-out-of-n rational secret sharing scheme which can function over an asynchronous broadcast channel without the use of cryptographic primitives and with a non-interactive dealer. This is possible because our scheme uses a small number, k+1, of honest players. The protocol is resilient to coalitions of size up to k and furthermore it is ε-resilient to coalitions of size up to and including m-1. The protocol will have a strict Nash equilibrium with probability Pr ( and an ε-Nash equilibrium with probability Pr ( . Furthermore, our protocol is immune to backward induction. Later on in the paper, we extend our results to include malicious players as well. We also show that our protocol handles the possibility of a player deviating in order to force anotherplayer to get a wrong value in what we believe to be a more time efficient manner than was done in Asharov and Lindell [5].

  20. High-quality asynchronous heralded single-photon source at telecom wavelength

    International Nuclear Information System (INIS)

    We report on the experimental realization and characterization of an asynchronous heralded single-photon source based on spontaneous parametric down-conversion. Photons at 1550 nm are heralded as being inside a single-mode fibre with more than 60% probability, and the multi-photon emission probability is reduced by a factor of up to more than 500 compared to Poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons, are compatible with practical applications needing very efficient and robust single-photon sources

  1. Asynchronous accelerator with RFQ injection for active longitudinal compression of accelerated bunches

    CERN Document Server

    Tumanyan, A R; Nikhogosyan, V C; Akopov, N Z; Guiragossian, Z G T; Martirosov, R M; Martirosyan, Yu.L.

    2000-01-01

    An asynchronous accelerator is described, in which the principle of itsoperation permits the active longitudinal bunch compression of acceleratedproton beams, to overcome the space charge limitation effects of intensebunches. It is shown that accelerated bunches from an RFQ linac can be adaptedfor Asynchronac injection for a multiple of choices in the accelerationfrequencies of the RFQ and the Asynchronac. The offered new type of acceleratorsystem is especially suitable to accelerate proton beams for up to 100MeVenergy and hundreds of mA average current.

  2. The analysis of an operating mode of the asynchronous generator with capacitor excitation

    Directory of Open Access Journals (Sweden)

    Postoronca S.

    2008-08-01

    Full Text Available On the basis of a symbolical method of calculation of electric circuits the analysis of features of work of the three-phase asynchronous generator with two windings on статоре and capacitor excitation is executed. Results of the analysis of influence on a phase corner of a current and voltage of a windings of excitation of the generator are submitted at change of its loading from a mode of idling up to a mode of short circuit. Recommendations on stabilization of a target voltage of the generator are formulated at change of its loading.

  3. A solid rotor iron free asynchronous generator for the production of high energy pulses

    International Nuclear Information System (INIS)

    A rotating machine capable of charging a noncooled magnetic storage coil is described. The rotor of the machine which is formed by metallic cylinder rotating at high speed, also behaves as a flywheel. The stator is composed of a three-phase winding connected to a system of rectifiers and power factor correcting condensers, thus forming an auto excited asynchronous generator. A very high power density is achieved because the machine has non ferrous winding, which permits a magnetic field of a few teslas. The basic machine theory and experimental model built are described

  4. Asynchronous transfer of individually addressable optical channels through a multimode fiber using phase conjugation

    CERN Document Server

    Czarske, Jueurgen W; Koukourakis, Nektarios; Buettner, Lars

    2016-01-01

    Multimode fibers are attractive for a variety of applications such as internet data transfer, data center hubs, micromanipulation, optogenetics and other biomedical applications. A major hurdle for imaging through multimode fibers is the occurring scrambling, resulting in a randomization of light. Recently, clear imaging has been successfully accomplished using wavefront shaping, but the spatial information was transferred synchronously only. We demonstrate asynchronous information transmission using individual phase conjugations by employing only one spatial light modulator with multiple windows. Our findings pave the way towards individual signal transfer inside strongly scattering media.

  5. The Paralleling of High Power High Frequency Amplifier Based on Synchronous and Asynchronous Control

    Institute of Scientific and Technical Information of China (English)

    程荣仓; 刘正之

    2004-01-01

    The vertical position of plasma in the HT-7U Tokamak is inherently unstable. In order to realize active stabilization, the response rate of the high-power high-frequency amplifier feeding the active control coils must be fast enough. This paper analyzes the paralleling scheme of the power amplifier through two kinds of control mode. One is the synchronous control; the other is the asynchronous control. Via the comparison of the two kinds of control mode, both of their characteristics are given in the text. At last, the analyzed result is verified by a small power experiment.

  6. Contribution à la commande robuste de la machine asynchrone à double alimentation

    OpenAIRE

    Salloum, Georges

    2007-01-01

    Le travail présenté dans cette thèse apporte, entre autres, une contribution aux méthodes d'analyse et de synthèse de la commande robuste des Machines Asynchrones à Double Alimentation (MADA) alimentées par deux onduleurs de tension avec deux bus continus distincts. Nous introduisons, dans un premier chapitre, la commande vectorielle classique de la MADA munie de capteurs mécaniques. Ce chapitre se distingue par une nouvelle approche pour assurer le découplage des courants de la MADA dans un ...

  7. Capacity enhancement of wavelength/time/space asynchronous optical CDMA with relaxed cross-correlation

    Science.gov (United States)

    Singh, Jaswinder

    2013-12-01

    The analysis of a three-dimensional (3-D) wavelength/time/space (W-T-S) asynchronous optical CDMA code family is presented considering MAI only under relaxed cross-correlation (λc ⩾ 1). Based on the code performance, it is shown that for code-limited systems (when W and/or T are non-prime), the number of generated codes and hence the supported users can be significantly increased by relaxing the cross-correlation constraint if a slight degradation in code performance can be tolerated.

  8. The analysis of an operating mode of the asynchronous generator with capacitor excitation

    OpenAIRE

    Postoronca S.; Berzan V.P.; Ermurachi Iu

    2008-01-01

    On the basis of a symbolical method of calculation of electric circuits the analysis of features of work of the three-phase asynchronous generator with two windings on статоре and capacitor excitation is executed. Results of the analysis of influence on a phase corner of a current and voltage of a windings of excitation of the generator are submitted at change of its loading from a mode of idling up to a mode of short circuit. Recommendations on stabilization of a target voltage of the genera...

  9. Using Team-Based Learning in an Online, Asynchronous Information Literacy Course

    Directory of Open Access Journals (Sweden)

    Allison Hosier

    2013-01-01

    Full Text Available Making information literacy instruction engaging to learners can be a challenge. Making it engaging in an online, asynchronous setting can be even more daunting. As students seek more opportunities for online learning, it’s becoming increasingly important to develop information literacy instruction that will promote engagement and enhance learning in the online environment. Team-Based Learning is a method of instruction that has transformed the atmosphere of a face-to-face information literacy course. This article explores the design and implementation of an online version of the same course where many of the benefits of Team-Based Learning were successfully transferred to the online setting.

  10. Evaluation of QoS differentiation mechanisms in asynchronous bufferless optical packet-switched networks

    DEFF Research Database (Denmark)

    Overby, H.; Stol, N.; Nord, Martin

    2006-01-01

    suitable for a future all-optical network. Hence, new schemes are needed to support QoS differentiation in optical packet-switched (OPS) networks. In this article we first present an overview of existing QoS differentiation mechanisms suitable for asynchronous bufferless OPS. We then compare the......Existing quality of service differentiation schemes for today's IP over point-to-point optical WDM networks take advantage of electronic RAM to implement traffic management algorithms in order to isolate the service classes. Since practical optical RAM is not available, these techniques are not...

  11. Asynchronous Object Storage with QoS for Scientific and Commercial Big Data

    Energy Technology Data Exchange (ETDEWEB)

    Brim, Michael J [ORNL; Dillow, David A [ORNL; Oral, H Sarp [ORNL; Settlemyer, Bradley W [ORNL; Wang, Feiyi [ORNL

    2013-01-01

    This paper presents our design for an asynchronous object storage system intended for use in scientific and commercial big data workloads. Use cases from the target workload do- mains are used to motivate the key abstractions used in the application programming interface (API). The architecture of the Scalable Object Store (SOS), a prototype object stor- age system that supports the API s facilities, is presented. The SOS serves as a vehicle for future research into scalable and resilient big data object storage. We briefly review our research into providing efficient storage servers capable of providing quality of service (QoS) contracts relevant for big data use cases.

  12. Increased Mass Loss and Asynchronous Behavior of Marine-Terminating Outlet Glaciers at Upernavik Isstrøm, NW Greenland

    DEFF Research Database (Denmark)

    Larsen, Signe Hillerup; Khan, Shfaqat Abbas; Ahlstrøm, Andreas Peter;

    2016-01-01

    In order to model and predict future behavior of marine terminating glaciers, it is essential to understand the different factors that control a glaciers response to climate change. Here we present a detailed study of the asynchronous changes in dynamic behavior of four adjacent marine-terminatin......In order to model and predict future behavior of marine terminating glaciers, it is essential to understand the different factors that control a glaciers response to climate change. Here we present a detailed study of the asynchronous changes in dynamic behavior of four adjacent marine...... between 1992 and 2013. These observations point out the fact that the UI glaciers are reacting to climate change on different timescales. The asynchronous behavior of the four neighboring glaciers is explained in terms of the individual glaciersâĂŹ geometry and terminus position. The northernmost glacier...

  13. Asynchronous Video Interviewing as a New Technology in Personnel Selection: The Applicant’s Point of View

    Science.gov (United States)

    Brenner, Falko S.; Ortner, Tuulia M.; Fay, Doris

    2016-01-01

    The present study aimed to integrate findings from technology acceptance research with research on applicant reactions to new technology for the emerging selection procedure of asynchronous video interviewing. One hundred six volunteers experienced asynchronous video interviewing and filled out several questionnaires including one on the applicants’ personalities. In line with previous technology acceptance research, the data revealed that perceived usefulness and perceived ease of use predicted attitudes toward asynchronous video interviewing. Furthermore, openness revealed to moderate the relation between perceived usefulness and attitudes toward this particular selection technology. No significant effects emerged for computer self-efficacy, job interview self-efficacy, extraversion, neuroticism, and conscientiousness. Theoretical and practical implications are discussed. PMID:27378969

  14. System and method for motor parameter estimation

    Energy Technology Data Exchange (ETDEWEB)

    Luhrs, Bin; Yan, Ting

    2014-03-18

    A system and method for determining unknown values of certain motor parameters includes a motor input device connectable to an electric motor having associated therewith values for known motor parameters and an unknown value of at least one motor parameter. The motor input device includes a processing unit that receives a first input from the electric motor comprising values for the known motor parameters for the electric motor and receive a second input comprising motor data on a plurality of reference motors, including values for motor parameters corresponding to the known motor parameters of the electric motor and values for motor parameters corresponding to the at least one unknown motor parameter value of the electric motor. The processor determines the unknown value of the at least one motor parameter from the first input and the second input and determines a motor management strategy for the electric motor based thereon.

  15. ANALYSIS OF PROCESSES IN AN INDEPENDENT GENERATOR WITH A NONCONTACT CASCADE THREE-PHASE MODULATED EXCITER VIA A STAR-CONNECTED CIRCUIT WITH A COMMON MODULATOR PHASE CONNECTION UNDER OPERATION TO AN INDUCTION MOTORS SITE

    Directory of Open Access Journals (Sweden)

    K.M. Vasyliv

    2013-04-01

    Full Text Available By means of a mathematical experiment, electromagnetic and electromechanical processes in an independent electric power supply system based on an asynchronized generator with a three-phase modulated exciter are investigated. The processes are analyzed to specify the working capacity of the power supply system during its operation to an induction motors site. Regularities of the electromagnetic and electromechanical processes behavior versus load intensity and the switch control system parameters are identified.

  16. Piezoelectric Rotary Tube Motor

    Science.gov (United States)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  17. Congenital Ocular Motor Apraxia

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-06-01

    Full Text Available The clinical and neuroradiological findings, and long-term intellectual prognosis in 10 patients (4 boys and 6 girls with congenital ocular motor apraxia (COMA are reviewed by researchers at Tottori University, Yonago, Japan.

  18. Chronic motor tic disorder

    Science.gov (United States)

    Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start at age 5 or 6 and get worse until age 12. They often improve during adulthood.

  19. Motor Vehicle Safety

    Science.gov (United States)

    ... these crashes is one part of motor vehicle safety. Here are some things you can do to ... speed or drive aggressively Don't drive impaired Safety also involves being aware of others. Share the ...

  20. Partial motor status epilepticus

    OpenAIRE

    Gilberto Rebello de Mattos; José C. Rollemberg Filho

    1992-01-01

    We report the case of a young female patient with photosensitive primary epilepsy who presented partial motor status epilepticus provoked by the act of shutting the eyes. Clinical, EEG and neuroimage data are presented and discussed.