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Sample records for asynchronous motors

  1. DYNAMIC REGIMES OF ASYNCHRONOUS MOTORS WITH CONCATENATED CAPACITORS

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    V. S. Malyar

    2015-04-01

    Full Text Available Purpose. Development of mathematical model for calculation of starting modes of asynchronous motor connected in series with capacitors. Method. Mathematical modeling of dynamic modes of asynchronous motors with lateral capacitor compensation of reactive power. Results. The calculation algorithm and results of mathematic modeling of processes during starting modes of asynchronous motor feeding from the network through capacitors connected in series are presented. It is shown that for some values of capacitance the self-excitation processes and subharmonic oscillations can appear. Scientific novelty. Mathematic modeling and research of processes in asynchronous motor under its feeding through capacitors is carried out for the first time. The calculation algorithm is based on the mathematical model of asynchronous motor with high level of adequacy, which takes into account the magnetic core saturation and the current displacement in limbs of the rotor. Practical implication. Developed mathematical model makes it possible to investigate the possibility of self-excitation modes appearing in condition of their feeding from line with lateral compensation of reactance in order to avoid the negative effects typical for them.

  2. Research on DSP-based Asynchronous Motor Control Technology

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    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.

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

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    B. I. Firago

    2015-01-01

    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

  4. New Approach to the Power Selection for Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    高建华; 胡洪国; 杨汝清

    2001-01-01

    The heating calculation of three-phase squirrel- cage asynchronous motor on the condition of starting for a prescribed rotary angle is firstly studied with time dissection method and its corresponding algorithm is provided. Then based upon the algorithm, a new method for motor power selection is established. Motor initial power determined by load power ischecked and modified in terms of time crit erion, heating criterion,and starting torque criterion.An appropriate motor power which meets three criterions is obtained at last, in the meantime, working displacement matrix andfrequency matrix used for control are acquired. Lifting motor of MDJ1800 low-level high- speed palletizer is taken as a reaI case in the paper.

  5. Realization of station for testing asynchronous three-phase motors

    Science.gov (United States)

    Wróbel, A.; Surma, W.

    2016-08-01

    Nowadays, you cannot imagine the construction and operation of machines without the use of electric motors [13-15]. The proposed position is designed to allow testing of asynchronous three-phase motors. The position consists of a tested engine and the engine running as a load, both engines combined with a mechanical clutch [2]. The value of the load is recorded by measuring shaft created with Strain Gauge Bridge. This concept will allow to study the basic parameters of the engines, visualization motor parameters both vector and scalar controlled, during varying load drive system. In addition, registration during the variable physical parameters of the working electric motor, controlled by a frequency converter or controlled by a contactor will be possible. Position is designed as a teaching and research position to characterize the engines. It will be also possible selection of inverter parameters.

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

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    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.

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

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    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.

  8. SELECTION OF METHOD FOR REGULATION OF TRACTOR PROPULSION ASYNCHRONOUS ELECTRIC MOTOR AND CONSTRUCTION OF MECHANICAL CHARACTERISTICS

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    Ch. I. Zhdanovich

    2015-01-01

    Full Text Available Nowadays the work is in progress to develop wheeled and caterpillar tractors with electromechanical transmission. Range of changes in transmission gear ratio while using propulsion electric motor depends on mechanical characteristics of a tractor propulsion electric motor which is equipped with electromechanical transmission. In case when the range is rather high then it is possible to minimize number of gearings in the tractor gearing box or exclude its usage at all. Type of the applied propulsion electric motor and regulation method specify type of mechanical characteristics (characteristics family of the propulsion electric motor.The paper considers a propulsion asynchronous electric motor with frequency control. While using frequency control it is possible to regulate electric motor revolutions by mutual changes in voltage and voltage frequency. There are various laws of mutual changes in voltage and frequency (regulation laws. Selection of a regulation law influences on type of mechanical characteristics of a propulsion electric motor. Application of any law can be admissible only for some specific range of voltage frequency otherwise it is possible to exceed some parameters (for example, admissible voltage in the winding of electric motor stator. It is necessary to ensure the required moment within wide range for a tractor propulsion electric motor. In this case losses in the electric motor must be minimal. Losses in the rotor of the propulsion asynchronous electric motor are directly proportional to its sliding and its best propulsion and mechanical properties of a mobile machine will be ensured in the case when sliding is preserved at a constant value. According to these reasons selection of regulation laws has been carried out for operation of the propulsion asynchronous electric motor with nominal sliding and mechanical characteristics at nominal sliding is conventionally called a nominal characteristics.The paper analyzes the possible

  9. 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.

  10. Zero Dynamics Analysis for Inverse Decoupling Control of Asynchronous Traction Motor

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    Haiying Dong

    2013-07-01

    Full Text Available Considering the problem for inverse system method in EMU AC induction traction motor linear decoupling, the zero dynamics subsystem will be separated from the original dynamic system through coordinate transformation. Firstly, a getting method for zero dynamics of the multiple input multiple output nonlinear system is discussed when γ<n. Second, the zero dynamics analysis for five order nonlinear model of asynchronous traction motor which base on the stationary coordinate system is given by using inverse decoupling method. The analysis results show that if the stability of the zero dynamics can be ensured, then the entire linearization of original nonlinear system is not necessary, need only partial linearization which effect on the external dynamic portion. The inverse decoupling process of asynchronous traction motor can be simplified by this conclusion.

  11. 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.

  12. New Asynchronous Motor Galvanometer%异步电动机专用电流计

    Institute of Scientific and Technical Information of China (English)

    彭鞍虹; 刘刚; 武传胜

    2001-01-01

    针对异步电动机电流计存在的耐起动电流冲击和指示正常运行电流之间的矛盾,试制了一种新型的异步电动机专用电流计,经测试完全满足工程要求.%A new special galvanometer for asynchronous motor is found, whichresolve the hitting current of motor starting and showing current when motor running. The testing result shows that it can satisfy engineering.

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

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    V. I. Lukovnikov

    2005-01-01

    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.

  14. TWO DESIGNS OF THE ELECTROMECHANICAL BRAKE EMBEDDED INTO AN ASYNCHRONOUS MOTOR

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    V. V. Solencov

    2016-01-01

    Full Text Available The significance of the braking devices is increasing due to the intensification of manufacturing, increase in the moving masses, speeds of movement and frequency of braking. During a short time period the braking device needs to convert a significant amount of mechanical energy into heat energy and transfer it into the environment without compromising the operability of both devices and machines in general. For electric actuators braking a normally closed mechanical brake is frequently used. When disconnecting the motor from the network the brake friction surfaces are closed and prevent rotation, and when the motor is switched on, they are opens under the action of the electromagnet, electro-hydraulic pusher, special electric motor, mechanical or pneumatic device. In the case of joint implementation of the asynchronous motor and the mechanical brake, the drive of quick stop is more compact and convenient. Such devices are further called asynchronous motors with electromechanical braking systems henceforth. The large number of requirements as well as different conditions of operation cause a large variety of designs of such motors. One of the major shortcomings of the functioning of well-known design is the periodic wear of the friction linings and the need for frequent replacement of them. The solution to this problem is the use of asynchronous motor with recessed combo braking device. However, for some mechanisms that do not require a smooth stop of the motor shaft and that have a speed of rotation of the motor shaft less than 1500 rpm, more simple and cheap solution would be the use of an electromechanical braking device with an air gap compensation. Due to wear of the friction linings the air gap of the electromagnet increases. Due to the compensation of the air gap of the electromagnet these devices make it possible to rub the material of the friction lining longer. The current designs of the electromechanical braking device with

  15. 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.

  16. An investigation of the dynamic electromechanical coupling effects in machine drive systems driven by asynchronous motors

    Science.gov (United States)

    Szolc, Tomasz; Konowrocki, Robert; Michajłow, Maciej; Pręgowska, Agnieszka

    2014-12-01

    In the paper dynamic electromechanical interaction between the rotating machine drive system and the electric driving motor is considered. The investigations are performed by means of the circuit model of the asynchronous motor as well as using an advanced structural hybrid model of the drive system. Using the analytical solutions applied for the electrical and the mechanical systems the electromagnetic stiffness and coefficient of damping, both generated by the electric motor rotationally interacting with the mechanical system of the given dynamic properties, were determined. By means of experimentally validated computational responses obtained for torsional harmonic excitation induced by the driven machine working tool, a modification of dynamic properties of the mechanical system by the electromagnetic flux between the stator and the rotor has been studied.

  17. 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.

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

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    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

  19. Asynchronous Electric Motor with Built-in Combined Braking Device Based on Electro-Mechanical Brake and Electro-Magnetic Clutch

    OpenAIRE

    V. V. Solenkov; Brel, V. V.

    2011-01-01

    The paper shows advantages and disadvantages of the known designs of asynchronous motors with electro-mechanical braking device. A new developed and studied asynchronous motor design with built-in combined braking device based on an electro-mechanical brake and an electro-magnetic clutch is given in the paper. The paper describes its advantages and prospects of its usage for electric drives operating in intermittent cycle.

  20. INFLUENCE OF THE TIME OF DISINHIBITION TO TRANSIENTS AND WEAR OF THE FRICTION LININGS IN AN ASYNCHRONOUS MOTOR

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    V. V. Solencov

    2016-01-01

    Full Text Available Time and the stopping distance of the electric drive with frequent starting-and-braking modes that contain embedded asynchronous motor with a recessed combined braking device depend on the moment of an electromagnet disinhibition. At the same time other important criteria are taken into the account, i.e. wear resistance of the brake device and the smoothness of the deceleration of the electric drive. In general such an asynchronous motor contains asynchronous engine with squirrel-cage rotor, electromechanical normally-closed brake, electromagnetical slip clutch and control circuit. The mechanical characteristics of the deceleration of asynchronous motor with recessed combined brake device at different moments of an electromagnet disinhibition are presented. The mathematical model is featured and the transients in such a motor are presented. Formation models for computer research were carried out in the Fortran 2008 programming language. Calculation of the system of differential equations was fulfilled by the Runge – Kutta method. The deceleration of the electromechanical brake at various speeds caused different time values and stopping distances. The plots of stopping distance and the braking time at various moments of an electromagnet disinhibition are demonstrated. The optimum moment of switching on an electromechanical brake, providing small stopping distance and the braking time is the time when the speed wвкл = 0,6–0,8 of the nominal. In this case the acceptable number of brake applications for friction linings (compared with mechanical braking will increase by 1.6–2.8 times. The pilot study confirmed the validity of the obtained mathematical models and discovered patterns.

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

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    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. 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

  3. 无轴承异步电动机研究发展现状∗%Research and Development Status of Bearingless Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    孙宇新; 杨玉伟

    2016-01-01

    The bearingless asynchronous motor has the excellent characteristics of asynchronous motor and the features of magnetic bearing, and has very broad development prospects in aerospace and high speed mechanical equipment fields. On account of the problem about the development of bearingless asynchronous motor, thorough research had been made by many domestic and foreign scholars, and gigantic progress had been made. In order to strengthen the research of bearingless asynchronous motor, the working principle of the bearingless asynchronous motor was introduced, and the representative structure design, mathematical model and control method of the bearingless asynchronous motor in recent years were overviewed.%无轴承异步电动机同时具备异步电动机的优良特性和磁轴承的特点,在航空航天、高速机械设备等领域具有非常广阔的应用前景。针对无轴承异步电动机的发展问题,国内外许多学者作了深入研究并取得了巨大进展。为了加强对无轴承异步电动机的研究,在叙述了无轴承异步电动机工作原理的基础上,详细综述了无轴承异步电动机近年来出现的具有代表性的结构设计、数学模型及控制方法。

  4. Static Parameter Identification of Asynchronous Motor%异步电机参数静态辨识

    Institute of Scientific and Technical Information of China (English)

    崔连香

    2013-01-01

    电机数学模型的参数直接影响无速度传感器矢量控制系统的性能。从异步电机动态数学模型及实际使用情况出发,提出了一种在被控电机静止的状态下借助 FFT及复数运算对电机参数进行辨识的方法。试验结果证明此方法简单可行,能为无速度传感器矢量控制系统提供较高精度的电机参数。%The parameter of motor mathematical model influences the performance no speed sensor vector control system. An identification method in a controlled motor static state by means of FFT and complex operation for identification of the motor parameters under the model of asynchronous motor and the actual application situation were introduced. The test results proved that this method was simple and practical. It could provide a highly precision motor parameters for the vector control system of no speed sensor.

  5. Asynchronization in Changes of Electrophysiology and Pathology of Spinal Cord Motor Neurons in Rats Following Middle Cerebral Artery Occlusion

    Institute of Scientific and Technical Information of China (English)

    Nan Lin; Ming-Sheng Liu; Si-Yuan Fan; Yu-Zhou Guan; Li-Ying Cui

    2015-01-01

    Background:Motor dysfunction is common in stroke patients.Clinical electrophysiological studies suggest that transsynaptic degeneration occurred in the lower motor neurons,while pathological evidence is lacked.This study aimed to combine the electrophysiological and pathological results to prove the existence of transsynaptic degeneration in the motor system after stroke.Methods:Modified neurologic severity score,electrophysiological,and pathological assessments were evaluated in rats before middle cerebral artery occlusion (MCAO),and at 24 hours,7 days,and 14 days after MCAO.Paired and independent-sample t-tests were applied to assess the changes of electrophysiological and pathological data.Results:Compound motor action potential amplitude in the paretic side was significantly lower than the nonparetic side at both 24 hours (61.9 ± 10.4 vs.66.6 ± 8.9,P < 0.05) and 7 days (60.9 ± 8.4 vs.67.3 ± 9.6,P < 0.05) after MCAO.Motor unit number estimation of the paretic side was significantly less than the nonparetic side (379.0 ± 84.6 vs.445.0 ± 89.5,P < 0.05) at 7 days after MCAO.Until 14 days after stroke,the pathological loss of motor neurons was detected.Motor neurons in 14-day MCAO group were significantly decreased,compared with control group (5.3 ± 0.7 vs.7.3 ± 1.8,P < 0.05).Conclusions:Both electrophysiological and pathological studies showed transsynaptic degeneration after stroke.This study identified the asynchronization in changes of electrophysiology and pathology.The abnormal physiological changes and function impairment can be detected in the early stage and recovered quickly,while the pathological loss of motor neuron can be detected only in a later stage.

  6. Research on Dynamic Simulation of asynchronous motor based on MATLAB/Simulink%基于MATLAB/Simulink的异步电机动态仿真探究

    Institute of Scientific and Technical Information of China (English)

    崔智皓; 赵琪月

    2014-01-01

    本文对异步电机在两相坐标系下的数学模型进行了分析,并利用MATLAB/Simulink仿真模块建立了基于两相坐标系的异步电机仿真模型。结果表明,异步电机的启动电流约为15A,启动转矩约为14 Nm。经过约0.5s后,异步电机达到稳定状态。分析结果可为异步电机的设计提供一定的理论依据。%This paper analyzes the mathematical model of the two-phase coordinate system of the asynchronous motor,and set up the simulation model of induction motor based on two-phase coordinate system by using MATLAB/Simulink simulation module.The results show that,the starting current of the asynchronous motor is about 15A,the starting torque is about 14 Nm. After about 0.5s,asynchronous motor reaches a steady state. The results can provide the theoretical basis for the design of asynchronous motor.

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

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    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. On the asynchronously continuous control of mobile robot movement by motor cortical spiking activity.

    Science.gov (United States)

    Xu, Zhiming; So, Rosa Q; Toe, Kyaw Kyar; Ang, Kai Keng; Guan, Cuntai

    2014-01-01

    This paper presents an asynchronously intracortical brain-computer interface (BCI) which allows the subject to continuously drive a mobile robot. This system has a great implication for disabled patients to move around. By carefully designing a multiclass support vector machine (SVM), the subject's self-paced instantaneous movement intents are continuously decoded to control the mobile robot. In particular, we studied the stability of the neural representation of the movement directions. Experimental results on the nonhuman primate showed that the overt movement directions were stably represented in ensemble of recorded units, and our SVM classifier could successfully decode such movements continuously along the desired movement path. However, the neural representation of the stop state for the self-paced control was not stably represented and could drift.

  9. Ship propulsion motor control based on asynchronous electric dynamometer%基于异步电力测功机的船舶推进电机控制

    Institute of Scientific and Technical Information of China (English)

    郭昊昊; 刘彦呈; 任俊杰

    2014-01-01

    对电力推进船舶中异步推进电机的控制问题展开研究,在MATLAB中分别建立异步电机的矢量控制模型、直接转矩控制模型以及异步电机互馈系统模型,并采用异步电力测功机模拟船舶的螺旋桨负载特性给推进电机提供螺旋桨负载。在实验室条件下应用变频器、PLC、上位机WINCC搭建相应的实物系统,仿真与试验研究验证了该方法的有效性。%Aiming at the control problem of asynchronous pro-pulsion motor in electric propulsion ship , the simulation mod-els of asynchronous motor vector control , direct torque con-trol, and reciprocal power-fed motor platform were built with MATLAB.Moreover, the asynchronous electric dynamometer was used to simulate the ship propeller load characteristic , so as to provide the propulsion motor with propeller load .A physical system including frequency converter , PLC, PC WINCC was built under laboratory conditions .Simulation and experiment results verify the effectiveness of this approach .

  10. Heating test on three-phase asynchronous motors by double-frequency or equivalent loading methods; Ensayo de calentamiento sobre motores asincronicos trifasicos por el metodo de la doble frecuencia o de la carga fantasma

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, Edgardo J.; Massa, Pablo A.; Urtiaga, Ricardo [La Plata Univ. Nacional (Argentina). Facultad de Ingenieria. Dept. de Electrotecnia

    1997-12-31

    This work comments the wiring temperature tests in three-phase high power asynchronous motors. It analyses an alternative method called double frequency or equivalent loading method which should be able to present similar effects of the direct method. A comparison between both methods is presented 4 refs., 5 figs., 1 tab.; e-mail: massa at isis.unlp.edu.ar

  11. 三相异步电动机用作异步发电机的探讨%Discussion on Three Phases Asynchronous Motor for Asynchronous Generator

    Institute of Scientific and Technical Information of China (English)

    王胤升

    2015-01-01

    异步发电机具有体积小、质量轻、价格低廉、安装与维修十分便捷等特点.在实际应用过程中,异步发电机可以满足紧急发电的需求,为生活和生产的有序、高效开展提供可靠的电能.%Asynchronous generator has the characteristics of small size, light weight, low cost, easy installation and maintenance, etc.. In the practical application process, the asynchronous generator can meet the needs of emergency power generation, and provide a reliable electric energy for life and production.

  12. Analysis of Three-Phase Squirrel-Cage Asynchronous Motor Vibration Fault%笼型三相异步电机振动故障解析

    Institute of Scientific and Technical Information of China (English)

    王强; 陈金刚

    2013-01-01

    介绍笼型三相异步电机的振动测量和振动超标造成的危害.从机械和电磁两方面阐述笼型三相异步电机的振动故障表现和修理预防措施.%The vibration measurement and vibration exceeding the standard hazards of squirrel-cage three-phase asynchronous motor were introduced.The vibration fault performances and repair prevention measures of three-phase squirrel-cage motor were elaborated from the mechanical and electromagnetic aspects.

  13. INVESTIGATION ON THE DIAGNOSIS OF SIMPLE AND COMBINES MECHANICAL FAULTS IN ASYNCHRONOUS MOTOR BASED ELECTRIC DRIVES

    Directory of Open Access Journals (Sweden)

    Bouras A. Karim

    2014-01-01

    Full Text Available In this study, the problems of mechanical unbalance, parallel and angular misalignments and their combinations are analyzed experimentally. Such frequent defects in the drives mainly in the major powers are also responsible for the bearings degradation. However, they have not raised the attention of researchers, given the complexity of their modeling. The combination of the phasic current signal analysis and the neutral current by the FFT supplemented by visual interpretation of patterns models these defects resulting from the 3D representation. The results obtained by using the proposed method show the efficiency to provide an accurate diagnosis of the state of the electric drive undergoing to isolated and combined mechanical defaults to a maintenance staff not necessarily expert of mechanical failure. The innovative approach validated experimentally on a 5.37 KW motor, offers an efficiency to provide an accurate diagnosis to a maintenance staff not necessarily composed of experts in this field.

  14. 主提升鼠笼式异步电动机变频改造%Frequency Transformation of Main Hoisting Squirrel-cage Asynchronous Motors

    Institute of Scientific and Technical Information of China (English)

    申昭

    2011-01-01

    主提升鼠笼式异步电动机变频调速系统的改造,其中以产生SPWM的HEF4752为控制核心,实现了鼠笼式异步电动机变频调速的闭环控制。%The transformation of the frequency controlling system of main hoisting squirrel-cage asynchronous motors realizes the closed-loop frequency control with the HEF4752 that produces SPWM as the core.

  15. YXKK系列高效率三相异步电机通风系统%Cooling System of YXKK Series High Efficiency Three Phase Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    韩振乾

    2016-01-01

    分析了YXKK系列高效率三相异步电机冷却系统。从通风系统方式、风扇结构、冷却器结构、定转子通风道分布、铜条转子与铸铝转子的选用5个方面,结合不同的数据分析,说明了高效率电机风路结构设计参数的优化方向。结论对高效率电机的风路设计具有一定的参考价值。%The YXKK series high efficiency three phase asynchronous motor cooling system was analyzed. Combined data analysis of different structures and illustrated the optimization of wind path structure design parameters of high efficiency motors, from five aspects including way ventilation system, fan structure, cooler structure, stator and rotor duct distribution, selection of copper rotor and cast aluminum rotor. The conclusion has some reference value for wind path structure design of high efficiency motors.

  16. Three-phase asynchronous motor electromagnetic vibration analysis%三相异步电动机的电磁振动分析

    Institute of Scientific and Technical Information of China (English)

    张诚诚; 李威扬; 唐子谋; 曾纯

    2014-01-01

    To establish a finite element model of three phase asynchronous motor, the calculation of air gap flux density, and Maxwell stress tensor method is used to calculate the radial electromagnetic force. The air gap flux density and radial force are changing with space and time, using Fourier analysis to solve their harmonic respectively, and discusses the relationship between the flux density and radial force. The analytical results from the finite element calculation results are compared. The article method is used to calculate the radial force and its harmonic motor can be applied to analyze the electromagnetic noise in motor design phase.%建立三相异步电动机的有限元模型,计算气隙磁密,进而利用Maxwell应力张量法计算径向电磁力。气隙磁密和径向力均随空间和时间变化,利用傅立叶分析分别求解它们的谐波,并讨论磁密和径向力之间的关系。将解析计算结果于有限元计算结果进行比较。利用文章方法计算的电机径向力及其谐波可应用于在电机设计阶段对电磁噪声进行分析。

  17. 基于正多面体法的单相异步电机优化设计%The Design Optimization of Single-phase Asynchronous Motor Based on Regular Polyhedron Method

    Institute of Scientific and Technical Information of China (English)

    马吉祥; 孙华

    2011-01-01

    单相异步电机是一种应用极为广泛的电机。电机优化设计是一种复杂的、有约束、非线性、混合离散多变量规划问题。本文选用正多面体优化算法对单相异步电机进行了优化设计。在数学模型的基础上,对正多面体优化算法进行了深入的分析和讨论,并对选定的电机进行优化,对获得的优化结果进行了比较和分析。结果表明,这种算法的性能较为理想,具有一定的实用价值。%Single-phase AC Asynchronous Motor is a very widely-used type electrical motor which has been thoroughly studied. Design optimization of electrical motors is a nonlinear constrained and mixed-discrete multiple variables optimization problem. In this thesis, the fundamental principle of Single-phase AC Asynchronous Motor is introduced and the Regular Polyhedron Method is fully discussed. We study its principle and give the detailed procedure for Single-phase AC Asynchronous Motor optimization. The algorithm is used to optimize selected Single-phase AC Asynchronous Motor and the results are accumulated and analyzed. The results prove that the performance of the algorithms is good and has some practical value.

  18. 异步电动机智能软起动器及其应用%The Intellectual Soft Start for Asynchronous Motor and its Applications

    Institute of Scientific and Technical Information of China (English)

    张文生; 刘耀年; 张玉霞

    2000-01-01

    The principle, functions and applications of soft starterfor asynchronous motor is described in this paper. By comparisonwith traditional starter, the paper indicates that soft starter is a newly-developed motor-starting device, which has a lot of advantagessuch as soft start, soft stop, light load, multifuncfion protectionand energy-saving, is innovative product for auto-transformerstarter and star- delta starter.%阐述了三相异步电动机软起动器的工作原理、功能及应用,通过与传统的电动机起动器比较,指出智能化软起动器是一种集电机软起动、软停车、轻载节能和多种保护于一体的新颖电机控制装置,是自耦降压起动器、星-三角变换器理想的更新换代产品。

  19. 石化生产中三相异步电机维护技术的研究%Study of maintenance technique of three-phase asynchronous motor in petrochemical production

    Institute of Scientific and Technical Information of China (English)

    李钢

    2015-01-01

    石化生产中的三相异步电机是最常用的和最重要的电气设备之一,通常情况下,石化生产中三相异步电机的用途是将电机所产生的电能转换形成为所需的机械能。由于三相异步电机结构相对简单、工作实用方便、且耐用坚固易于维修。为了使三相异步电机能够在石化生产中安全稳定的运行工作需要对其进行一定的维护,尽可能的减少三相异步电机的故障。%The three-phase asynchronous motor is the most commonly used in petrochemical production and one of the most important electrical equipment. Under normal circumstances,the use of three-phase asynchronous motor in petrochemical production is to convert motor electrical energy generated by the formation to the desired mechanical energy. Because of the three-phase asynchronous motor is relatively simple in structure,convenient in practical work,strong and durable and easy to maintenance. Certain maintenance is needed for the three-phase asynchronous motor to operate in the petrochemical production safely and stably, and reduce its fault possibly.

  20. Analysis of Asynchronous Motor Phased Optimization of Energy-Saving Control Technology%异步电机相控优化节能控制技术分析

    Institute of Scientific and Technical Information of China (English)

    徐燕; 杨跃农

    2012-01-01

    Phased optimization and energy saving of AC asynchronous motor running problem was analyzed and researched. A comprehensive energy-saving control program of asynchronous motor starting and running was introduced. The program was simple in structure, speed performance, and reliable performance.%对交流异步电动机的相控优化节能运行问题作了全面的分析和研究,提出了异步电动机起动和运行的综合节能控制方案.该综合节能控制方案结构简单,调速性能好,性能可靠.

  1. 利用时间延迟状态反馈实现异步电机的混沌合成%Chaos Synthesis of Asynchronous Motor by Time-Delayed State Feedback

    Institute of Scientific and Technical Information of China (English)

    李卫东; 唐斌

    2012-01-01

    为了在三相交流异步电机的运行过程中实现混沌合成,采用非线性系统的微分几何理论和时间延迟反馈控制的方法,设计了混沌合成控制器.该控制器通过对三相交流异步电机模型的简化分析,并利用非线性控制理论的状态反馈精确线性化方法来设计.应该此控制器即可得到异步电机运行时的混沌合成.应用Matlab软件中Simulink 工具进行仿真分析,仿真结果说明利用时间延迟状态反馈设计的控制器实现异步电机的混沌合成是完全合理可行的,运行结果也是满足要求的.%The chaos synthesis controller is designed using the method of differential geometry theory of nonlinear systems and time-delayed feedback control to realize chaos synthesis in running process of three-phase alternating current (AC) asynchronous motor. The exact linearization approach by state feedback of nonlinear control theory is used for controller design and through simplified analysis on the model of three-phase AC asynchronous motor. Chaos synthesis is got when asynchronous motor running by this controller. Simulink tool in Matlab software is used for Simulation analysis. The simulation results show that the time-delayed state feedback method designed controller implementing chaos synthesis of asynchronous motor is feasible and the control result is satisfied.

  2. Disturbance Research of H2/H∞Mixed Controller on the Asynchronous Motor%H2/H∞混合控制器对异步电动机扰动研究

    Institute of Scientific and Technical Information of China (English)

    罗亚琴; 付铮铮; 姚均天; 杨宜

    2014-01-01

    The asynchronous motor control is studied in this paper. Because of uncertainty, the model of the asynchronous motor is linearized first, and then the mixed H2/H∞controller is used in the asynchronous motor speed adjusting system, and the performance requirements of the induction motor speed adjusting system transforms into the design problem of the mixed H2/H∞controller. The design method based on the H2/H∞controller is applied in the induction motor control system, and ensure the system robust stability, dynamic stability of the closed loop system, and ensure the stability of the induction motor's speed under load disturbance and other factors.%研究异步电动机的控制,针对异步电动机模型的不确定性问题,首先将其线性化,然后将H2/H∞控制器应用于异步电动机的调速系统中,将异步电动机调速系统的性能要求转化为混合H2/H∞控制器的设计问题。提出将基于H2/H∞控制器参数的设计方法运用到异步电动机控制系统中,很好地保证了负载等外部因素扰动情况下的系统鲁棒稳定性,保证闭环系统具有的动态和稳定性能,很好的保证了异步电动机对扰动的稳定性。

  3. An Asynchronous Electric Drive with the Indirect Control of the Output Variables

    Directory of Open Access Journals (Sweden)

    Glazachev Alexander V.

    2017-01-01

    Full Text Available The article gives a mathematical description of an asynchronous motor with a device of indirect control of the electromagnetic torque and the angular velocity of the asynchronous motor in the electric drive that allows to prove on its basis the method of monitoring the output variables of the asynchronous electric motor. The simulation model of an asynchronous motor with a device of indirect control of the output variables of the asynchronous motor and the main results of the study have been given.

  4. 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.

  5. 转子电阻变化对异步电机直接转矩控制影响的仿真分析%Simulation analysis of influence of rotor resistance variation on direct self control for asynchronous motor

    Institute of Scientific and Technical Information of China (English)

    梁兵

    2001-01-01

    使用MATLAB/SIMULINK语言建立三相异步电机直接转矩控制仿真模型。通过对不同转子电阻在直接转矩控制下得到的电机转速和定子磁链图形的分析比较,得出了转子电阻变化对交流异步电机直接转矩控制没有影响的结论。%Simulation model is built up for direct self control of 3-phaseasynchronous motor using MATLAB/SIMULINK software. By analysis and comparison of motor rotating speed and stator magnetic flux linkage diagram under direct self control at different rotor resistance, the conclusion is shown that the rotor resistance variation will exert no influence on the direct self control for ac asynchronous motor.

  6. 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

  7. 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.

  8. 绕线式异步电动机调压节能运行研究%Research on the Operation Performance of Wound Rotor Asynchronous Motors in Voltage Regulation and Energy Saving

    Institute of Scientific and Technical Information of China (English)

    冯韧; 王兵; 侯黎平

    2016-01-01

    Based on the fact that asynchronous motors are characterized with periodic load operation, the optimal voltage of wound rotor asynchronous motors has been determined under no-load and light-load operating modes. With the load ratio a constant, the power factor under the optimal voltage is greater than that under the rated voltage. In light of the features of winding rotor asynchronous motors, a research has been conducted on the side series resistance starting and the capacity of voltage regulation and energy-saving series under series resistance speed regulation. When a resistance of 2 is connected in series with the rotor circuit, an accelerated starting of the motor has thus achieved. With the optimal voltage a constant, the electromagnetic torque remains constant before and after the series resistance has been connected with the rotor circuit. A step-down series resistance speed regulation model of wound rotor asynchronous motors has been set up to work out the relationship between the energy consumption of the rotor turn-on and rotor series resistance under a constant optimal voltage. When the load factor of the motor is in the range of 0%~50%, a certain energy-saving space could be obtained by appropriately reducing the power supply voltage, thus verifying the feasibility of the energy saving operation under the light load rotor series resistance voltage regulation of wound rotor asynchronous motors under the optimal voltage.%根据异步电动机带周期性负载运行的特点,确定了绕线式异步电动机处于空载、轻载运行状态下的最优电压,且维持负载率不变时,其在最优电压下的功率因数大于其在额定电压下的。针对绕线式异步电动机的特性,研究了其转子侧串电阻启动及串电阻调速下调压节能的运行状态,得知当转子回路中串入2电阻时,可加速电机启动,且在最优电压一定时,串电阻前后的电磁转矩恒定。通过搭建绕线式异步电动

  9. 异步电机DTC系统脉动最小化研究%Study of Torque Ripple Minimization for Direct Torque Control of Asynchronous Motors

    Institute of Scientific and Technical Information of China (English)

    孙鹏

    2014-01-01

    Direct torque control has been applied widely due to its simple arithmetic, fast transient response and robust stability to parameter changed. As for the conventional direct torque control system for asynchronous motors, there is the effect of voltage space vector on the magnitude of stator flux and flux angle, especially there are large ripples at low speed. Aiming at this issue and based on conventional DTC, a new control strategy is proposed in this paper, this strategy combines flux linkage section subdivision control with synthesizing vectors and can improve the torque response time by introducing Fussy control algorithm, thereby reducing torque ripples effectively. Simulation results show that the strategy can greatly reduce the torque ripples and has a better dynamic and steady performance.%直接转矩控制具有控制简单、动态响应迅速、对参数变化鲁棒性强的特点,因此得到了广泛的应用。在传统的异步电动机直接转矩控制系统中,存在电压空间矢量对定子磁链幅值和磁通角的影响,特别是低速时系统脉动大。针对此问题,文章提出了一种的新的控制方法,该方法将磁链区间细分控制与电压矢量合成结合在一起,并通过引入模糊控制算法进一步提高了转矩响应时间,且减小了转矩脉动。仿真结果表明,本控制方法可以大大减小转矩脉动,具有较好的动静态性能。

  10. Calculation and Analysis on Electro-magnetic Field of the Asynchronous Traction Motor for Freight Locomotive%货运机车异步牵引电机电磁场计算与分析

    Institute of Scientific and Technical Information of China (English)

    阮鸿芳; 于海涛

    2015-01-01

    Taking the AC asynchronous traction mo-tor of the HXD1C high-power locomotive as example, the 2D mathematic model of the electro-magnetic field was established and its solved region was determined either. The finite element method was applied to calculate the electro-magnetic parameters of the traction motor while the calculated result was compared with the actually-test data, and then, came the beneficial conclusion.%以大功率交流传动H X D1C机车用异步牵引电机为例,建立电机二维电磁场数学模型,并确定其求解域.利用有限元方法,计算牵引电机电磁参数,并将计算结果与实测数据进行对比,得出一些有益的结论.

  11. YRKK800-10 10 kV型绕线式三相异步电动机的研制%Develop of YRKK800-10 10 kV Wound Three-Phase Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    解育男

    2013-01-01

    The design of electromagnetism,stator,rotor,cooling system,collector ring and rotor down-lead about air cooling YRKK800-10 10 kV wound three-phase asynchronous motor were discussed,laying the foundation for the similarity product designation.%讨论了YRKK800-10 10 kV型绕线式三相异步电动机的电磁设计,定、转子结构,转子引线结构,轴向通风冷却系统,转子滑环结构的设计特点和制造过程中遇到的问题和解决方法,为类似结构产品的设计提供参考.

  12. Modelling and Simulation of Vector Control Adjustable-speed System of Asynchronous Motor%三相异步电动机矢量控制调速系统的建模与仿真

    Institute of Scientific and Technical Information of China (English)

    李家荣; 邓智泉

    2001-01-01

    简述了Matlab/Simulink软件的核心内容及已获实际应用的异步电机矢量变换控制系统的数学模型,介绍了用Matlab/Simulink为该系统建立完整仿真模型的过程,最后给出仿真结果.%Introduction is made to the core contents of Matlab/Simulink software and the applied maths model of vector control adjustable-speed system of asynchronous motor. Meanwhile, a brief account is given to the process in which simulation model is established for this system by Matlab/Simulink as well as the simulation results.

  13. 基于参数回归模型的异步电动机等值电路参数测定%Asynchronous Motor Parameter Determination Using Model Regression Method

    Institute of Scientific and Technical Information of China (English)

    林友杰; 谢卫才

    2011-01-01

    在参数回归模型的基础上,对更接近于实际小转差运行工况的负载运行的实验数据进行参数回归,不仅可以避免常见测定方法的不足,还可以避免测量误差的干扰,得到更为准确的异步电动机等值电路参数.利用1stopt进行实验数据的参数回归处理,可以进行容易地解出异步电动机参数回归模型方程的解.探寻了几种回归模式在获取准确参数方面的可能性,表明基于参数回归模型的异步电动机等值电路参数的1stopt测定方法具有实际的指导意义和应用价值.%The model regression for the parameters of asynchronous motor equivalent circuit based on its parameter regression model and the use of the actual small slip experimental data can avoid the disadvantage of the common method and the measurement error disturbing, and thus the more accurate parameter can be obtained. The parameter regression for the experiment data using 1 stopt can easily resolve the equations of the model regression. Possibility for several model regression mode was studied. The result shows that the asynchronous motor parameter regression model using lstopt for resolving in the equivalent circuit parameter bears actual instruct sense and applied value.

  14. 基于热网络的异步电机过载保护模型及数字算法%Overload Protection Model of Asynchronous Motor Basing on Thermal Network and Digital Algorithm

    Institute of Scientific and Technical Information of China (English)

    李洪涛; 李奎; 倪素娟

    2011-01-01

    According to the different heat sources within the motor, the motor can be divided to five parts,namely, the stator core,the stator slot winding,rotor bar and rotor core, then the lumped parameter method was respectively used to them to establish an five-order thermal network model of asynchronous motor. With ensuring the accuracy of the thermal models,the full-order thermal models could be systematically reduced via pole-zero cancellation. As a result, a low-order thermal network models, which had nearly the major response characteristics in the frequency band of interest and was more simple for estimating the motor temperature, was obtained. In order to make the low-order themal network models could be applied to intelligent motor thermal overload protection relay, an discretization algorithm was proposed.%以试验样机为例,依据电机内部不同的发热源将电机分作五部分,即定子铁心和机壳、定子槽绕组、定子绕组端部、转子导条和转子铁心,分别应用集总参数法建立了五阶的热网络分布模型.在保证模型精度的前提下,利用零极点对消法对五阶热模型进行了降阶简化,从而得到了反应电机温升主要特性、精度高、计算简单的低阶热网络模型.对低阶热模型进行离散化,得到了适用于智能电机过载保护继电器的数字算法.

  15. 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.

  16. 异步电机转子电阻辩识方法的建模与仿真%Model and Simulation Identification Method of Rotor Resistance of Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    鲍建成

    2012-01-01

    Asynchronous motor rotor resistance changes affect the control precision of the system, because temperature and skin effect, rotor resistance changes has nonlinear. In order to identificate the rotor resistance accurately and rapidly, an asynchronous motor rotor resistance identificate method was proposed based on extended kalman filter in this paper. Taking Rotor resistance as a system state variable, a rotor resistance identification was designed base on extended Kalman filtering technology. Through the measuring the voltage and curren of the motor stator, the rotor resistance identification value was obtained. The simulation model was built with MATLAB/Simulink system, and the simulation results show that the proposed mehod can rapidly and accurately identify rotor resistance and improve the precision of rotor resistance.%研究异步电机稳定性优化控制问题,异步电机转子电阻受温度变化、集肤效应等影响,具有时变性和非线性,影响系统稳定性分析.传统方法对异步电机转子电阻状态辩识准确率低.为了准确和快速对转子电阻进行状态辩识,提出一种扩展卡尔曼滤波的异步电机转子电阻辩识方法.将转子电阻看成系统状态变量,设计一种扩展卡尔曼滤波技术的转子电阻估计器,通过测量电机定子电压、电流,实现对转子电阻在线辩识.在MATLAB/Simulink中建立仿真模型,仿真结果表明,异步电机转子电阻改进辩识方法可提高转子电阻辨识准确率.

  17. 基于概率神经网络模型的异步电机故障诊断%Based on Probabilistic Neural Network Model for Asynchronous Motor Fault Diagnosis

    Institute of Scientific and Technical Information of China (English)

    李天玉; 吴楠

    2013-01-01

    针对传统故障诊断方法的局限性,提出一种基于概率神经网络(PNN)的诊断方法.以异步电机转子断条、偏心、失电残压等故障为例进行了诊断研究,通过选取故障样本来训练PNN,将故障信息输入训练好的PNN模型后,由输出结果即可判断发生的故障种类.MATLAB仿真表明,基于PNN的电机故障诊断方法能有效识别出电机故障,故障诊断准确率高,易于工程实现.但神经网络还处于发展阶段,仍有不少问题需进一步研究.%According to the limitation of traditional fault diagnosis method, a diagnosis method based on probabilistic neural network was proposed. An example of asynchronous motor rotor with broken, eccentric, electric residual pressure fault was done. By choosing fault samples to train PNN, and then inputting the diagnosis information to the trained model of PNN, the occurred fault types could be judged from the output results. MATLAB simulation showed that diagnosis method of the motor based on probabilistic neural network could effectively identify motor fault and the fault diagnostic accuracy rate was so high that it could be easily implemented in engineering projection. But as neural network itself was undergoing developing, many problems need to be further studied.

  18. 三相交流异步电动机阻抗参数计算%Impedance Parameter Calculation of Three-phase AC Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    姚家祎

    2016-01-01

    结合电动机产品样本数据,分别采用计算法、 GB/T 21066-2007《船舶和移动式及固定式近海设施的电气装置三相交流短路电流计算方法》给出的推荐值和试验法3种方法进行计算,分析比较其计算结果的准确性,建议尽量按电动机容量相应的技术数据,用计算方法求电动机阻抗参数;并建议电动机厂商在样本中给出阻抗值,方便工程设计人员计算电动机短路电流。%Based on the sample data of motor, three methods, i. e. calculation method, recommended value and test method, of which the recommended value is recorded in the Electrical Installations of Ships and Mobile and Fixed Offshore Units—Procedures for Calculating Short-circuit Currents in Three-phase A. C. (GB/T 21066-2007), are adopted respectively, so as to analyze and compare the accuracy of computations. It is suggested that the motor impedance parameter is determined by the calculation method according to the technical data of motor capacity, and that the impedance is available for the sample of motor manufacturer so that the engineering designer can calculate the short-circuit current of motor more easily.

  19. 异步电机定子叠频法温升试验及效率研究综述%Overview on asynchronous motor temperature rise testing and efficiency evaluation by method of stator mixed-frequency equivalent loading

    Institute of Scientific and Technical Information of China (English)

    王伟光; 陈卫杰; 李伟; 梁艳萍; 李藏雪

    2016-01-01

    Large power vertical asynchronous motor is hard to find a proper coupler or load. So, temperature rise test should be simulated by equivalent loading using stator mixed⁃frequency method, i. e. , to superpose the primary and the secondary power supply vectors with similar frequency thus to form a new beat frequency power supply which should be applied at the terminal of the motor. The air⁃gap magnetic field generates pulse oscillation near the synchronous speed making the rotor of the asynchronous motor have a frequent status switching at generator and mo⁃tor. The moment of inertia of the rotor is changed, which excites electrical current flowing to the motor winding, and from the viewpoint of motor loss, it corresponds to introducing an equivalent mechanical loading. In this paper, the variation rules for the loss of the asynchronous motor, the estimated error for the efficiency and temperature rise at mixed⁃frequency are discussed, at mixed frequency, the temperature rise increases by 2~6K, and the efficiency decreases by 0�5 to 1 percent. With a deepening understanding of mixed⁃frequency, this will give a hint to the e⁃lectromagnetism design, ventilation calculation and lubrication calculation of sliding bearing. The feasibility of the mixed⁃frequency test of water lubricated thrust bearing is put forward. At present, our mixed⁃frequency technology is still at the developing period, and the aim is by referring to latest motor standard from IEEE112⁃B of the U. S. , the JEC⁃2137 of Japan, AS/NS1359�5 of Australia and IEC34⁃2 of EU, to improve related part of the mixed fre⁃quency test of our GB/T1032 in detail. Finally, the existing problems in the mixed⁃frequency method and the fu⁃ture study aspects are discussed in the paper.%大功率及立式异步电机难以找到恰当的对拖机组或负载,需要通过定子叠频等效负载法来模拟温升试验,即将两种相近频率主、副电源矢量叠加形成新的拍频

  20. Study and Manufacture of Meet NEMA Standard's Premium Three-Phase Explosion Proof Asynchronous Motor%符合尼玛标准的防爆超高效三相异步电动机研制

    Institute of Scientific and Technical Information of China (English)

    王勃; 王少景

    2011-01-01

    简要介绍了研制的符合尼玛标准的防爆超高效三相异步电动机的主要技术参数与结构设计特点.该电机采用优质硅钢片与退火工艺降低铁耗、低谐波绕组降低铜耗、特殊转子表面加工和酸洗工艺降低杂耗等.同时介绍了UL的防爆规范.%The NEMA premium three-phase explosion proof asynchronous motor's research, fundamental parameters, structure, and key technique were introduced. For example, stator and rotor cores were laminated with highclass electrical silicon steel sheets with high permeability and annealing process to reduce iron loss. Low harmonic winding was used to reduce stator copper loss. Rotor surface was lathed with special technology and acid washing to reduce stray loss, etc. Then it showed UL classifications, groups and divisions.

  1. 基于小波变换的鼠笼式异步电动机故障诊断%Research on Squirrel-cage Asynchronous Motor Fault Diagnosis Based on Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    成函

    2015-01-01

    Wavelet Transform has a good localization capability in the time domain and frequency domain , especially being sensitive to the mutation point of the signal . Due to the multiresolution properties , it can be close to the spectrum , and has outstanding effect on Extraction of fault signal . This paper discussed wavelet analysis and its application in fault diagnosis , and verified the accuracy of the detection method of wavelet transform in squirrel-cage asynchronous motor fault .%小波变换在时域和频域都具有良好的局部化能力,尤其是对信号的突变点很敏感,其多分辨率性质可逼近细化频谱,对故障信号提取有突出的作用。本文通过算例论述了小波分析在故障诊断中的研究和应用,验证了小波变换方法检测鼠笼式异步电动机故障的准确性。

  2. 异步电动机液体变阻器软启动控制设计%Soft Start Control Design for the Liquid Rheostat of Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    徐腊梅; 贺平平; 陈彦龙

    2011-01-01

    The initial firing current of AC asynchronous motor in the starting time is 5 - 7 times of that in normal operation. The oversized start current exerts the disadvantageous impact on the power supply electrical network, and affects normal operation of the equipment. A control method named liquid rheostat resistance "soft start" was proposed to reduce impulse current generated in period of motor starting. The resistance of liquid rheostat which was concatenated in rotor loop was controllable. It reduces with start time increasing;thus starting time and initial firing current are controllable. The high power factor and the best starting torque can be obtained.%交流异步电动机在启动时的启动电流是正常运行电流的5~7倍,过大的启动电流会对供电电网产生不利的冲击,影响设备的正常运行.为减小电动机启动时产生的冲击电流,提出了液体变阻器软启动的控制方法,通过改变串接在转子回路中的液体变阻器的电阻,使其阻值随启动时间的增加而减少,从而调整启动时间和启动电流,并获得较高功率因数和最佳启动转矩.

  3. 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。

  4. 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。

  5. Estimation of Influence of Supply Network Power and Parameters of «Frequency Converter - Asynchronous Motor» System on Harmonic Spectrum of Its Discontinuous Input Current

    OpenAIRE

    Firago, B. I.; K. M. Medvedev

    2006-01-01

    The purpose of the paper is to investigate dependence of input current harmonic spectrum of modern frequency converters with uncontrolled rectifiers on supply network power , rated power and motor load, and also the DC filter capacity. Results of the investigations are given in the form of the corresponding dependencies and an estimation of correspondence of higher current harmonic levels generated by a frequency converter to the existing state standard.

  6. 微型三相异步电动机设计分析%Design Analysis of Miniature Three-phase Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    刘俊利; 邢海龙

    2011-01-01

    This paper introduced the design of a three-phase induction motor of 15 W, presented the demands of this induction motor. The inner diameter and length of the armature and the air gap length were determined firstly. The slots number of the armature and the cage rotor were selected to reduce the additional loss, vibration and noise. The shape of the armature slot and cage slot were chose respectively. The single layer concentrate full pitch winding was employed. The calculation results show the design scheme can meet the demands of the three-phase induction motor of 15W.%介绍了15 W三相异步电动机的电磁设计.针对15 W三相异步电动机的技术指标,分析了其主要尺寸的确定、定转子槽数的配合、定转子槽形的设计及电枢绕组形式的选择.采用磁路法和电磁场仿真对电磁方案进行了性能计算,两种方法的计算结果表明该电磁方案能够满足技术指标要求.

  7. Discussion on the no-load current of three-phase asynchronous motor%浅论三相异步电动机的空载电流

    Institute of Scientific and Technical Information of China (English)

    杨立峰; 郭宗跃; 牛玉敏

    2015-01-01

    该文对以往利用空载电流判断电动机修理质量的方法进行了分析,提出了根据功率因数cosφ和效率η之积的经验值进行经验额定电流计算的方法。并根据长期现场工作经验,针对不同类型的电动机,计算出的经验额定电流和实测的空载电流,给出了鉴定电动机修理质量的具体判断依据。%In this paper, we analysis the conventional method of using the no-load current to judge the quality of motor repairs. Presents mehtod according to the product empirical value of the power factor cosφand efifciencyηto caculate experience rated current.. Based on the long-term ifeld experience, for different types of motor, according to the experience rated current calculated and load current measured, eventually give a speciifc identiifcation basis for motor repair quality.

  8. 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.

  9. Mechatronic Frequency-control High-efficiency Asynchronous Motors%机电一体变频高效异步电动机

    Institute of Scientific and Technical Information of China (English)

    邢一均; 裘伟平; 吴妍; 傅志华; 李欣建

    2013-01-01

    变频调速以其优异的调速和起、制动性能,高效率、高功率因数和节能,被国内外公认为最有发展前途的调速方式。变频调速器与变频调速电动机组成的交流调速系统具有调速精度高、调速范围广、可靠性强和易于实现各种自动控制的特点,逐渐成为交流调速方式的主流。%Because of the excellent performance of speed-regulation, brake, high-efifciency, better power factor and energy-saving of the frequency-control motor, it was considered as the most prosperous speed-regulation way in future. The mechatronic AC speed-regulation composed of the inverter and frequency-control speed-regulation motor possessed the features of precise speed-regulation, wide range of the speed, high reliability and easy to realize vari-ous kinds of auto-control, becoming the main stream of the AC speed regulation.

  10. 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

  11. 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 g...

  12. 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...

  13. 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.

  14. Multiparty Asynchronous Session Types

    DEFF Research Database (Denmark)

    Honda, Kohei; Yoshida, Nobuko; Carbone, Marco

    2016-01-01

    peers are directly abstracted as a global scenario. Global types retain the friendly type syntax of binary session types while specifying dependencies and capturing complex causal chains of multiparty asynchronous interactions. A global type plays the role of a shared agreement among communication peers...

  15. 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

  16. 基于改进LS-SVM的异步电机转子故障诊断%Rotor Fault Diagnosis of Asynchronous Motor Based on Improved LS-SVM

    Institute of Scientific and Technical Information of China (English)

    李伟伟; 王莉; 张琳; 冯丹

    2016-01-01

    In order to improve rotor fault diagnosis accuracy of the asynchronous motor,a multi-class classification algorithm based on improved Least Square Support Vector Machine (LS-SVM)is proposed. First the fault character vectors are collected from the signal spectrum that is acquired from the signals of the motor stator current fault by FFT. Then when the feature vectors are used as the inputs of the improved algorithm for fault diagnosis,the improved algorithm confirms the weight of all faults with analytic hierarchy process,determines the order of the fault diagnosis in accordance with the weight and achieves the fault classification in turn on the basis of the former multi-class algorithm. Experimental results show that the improved algorithm saves time and improves the diagnosis accuracy when it is used for fault diagnosis and it has a bright prospect for generalization.%为了提高异步电动机转子故障的诊断精度,给出了一种基于改进最小二乘支持向量机(LS-SVM)的多故障分类算法。首先运用FFT处理电机的定子电流信号得到信号频谱图,从中提取故障特征向量;然后将特征向量送入改进算法进行故障诊断时,在原有多分类算法的基础上引入层次分析法确定故障类别的权重,根据权重值确定故障的诊断顺序,依次进行故障分类。实验表明,改进算法用于故障诊断节省了诊断时间,提高了诊断精度,具有很好的推广前景。

  17. Asynchronous DSP-core

    OpenAIRE

    Østvand, Jon

    2007-01-01

    In this thesis multipliers with and without completion detection has been implemented using a 90 nm library to compare their properties reguarding completion time, area and power consumption. The structures tested were array and shiftand-add multipliers. The results were that when having larger bit-lengths, an asynchronous shift-and-add multiplier with completion detection can yield good completion times compared to a regular shift-and-add multiplier. Due to the large cost in area and power c...

  18. 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.

  19. Study on Loss and Reactive Power Characteristics of Cage Asynchronous Motor with Generator and Motor Modes%笼型异步电机在发电和电动工况下的损耗和无功特性研究

    Institute of Scientific and Technical Information of China (English)

    牟树贞; 赵海森; 罗应立; 姚丙雷

    2012-01-01

    In some industrial applications, cage asynchronous motors usually run with a continuous inter-conversion of generator and motor modes. In order to study the loss and reactive power characteristics under those complex conditions, taking a 5. 5 kW motor as an example, the experimental scheme to simulate the generator and motor modes was designed, the stator and rotor copper loss, fundamental iron loss, excess loss and reactive power were systematically tested and analyzed with load torque variation. In addition, considering that the stator current can be measured easily on field, it also further concluded the general rules of the above loss term varying with stator current. The results showed that, with the same stator current, fundamental iron loss, excess loss and reactive power in generator mode were more than the ones in motor modes, under rated stator current condition, the total losses and reactive power in the generator mode are 9% and 20% over than the ones in the motor mode respectively.%在某些工业生产场合,笼型异步电机通常连续运行在电动和发电相互转换的工况,为了研究在此类复杂工况下电机损耗和无功特性,以一台5.5 kW异步电机为例,设计了能够模拟电动和发电工况的试验方案,系统测试并分析得出电机内部定转子铜耗、基本铁耗、附加损耗及无功需求随负载转矩的变化规律.此外,考虑到定子电流在实际生产中易测量,进一步分析了上述各项损耗随定子电流变化的一般规律.结果显示,定子电流相同时,发电工况的基本铁耗、附加损耗,以及无功需求均大于电动工况,额定电流的发电工况下电机总损耗和无功需求比电动工况分别高约9%和20%.

  20. 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)

  1. IDENTIFICATION AND CONTROL OF AN ASYNCHRONOUS MACHINE USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    A ZERGAOUI

    2000-06-01

    Full Text Available In this work, we present the application of artificial neural networks to the identification and control of the asynchronous motor, which is a complex nonlinear system with variable internal dynamics.  We show that neural networks can be applied to control the stator currents of the induction motor.  The results of the different simulations are presented to evaluate the performance of the neural controller proposed.

  2. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  3. 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.

  4. Finite Element Calculation of Radial Electromagnetic Force Wave in Squirrel-Cage Asynchronous Motors%笼型异步电动机径向电磁力波的有限元计算

    Institute of Scientific and Technical Information of China (English)

    王荀; 邱阿瑞

    2012-01-01

    In this paper, the field-circuit coupled time-stepping finite element model of squirrel-cage asynchronous motor is presented and the validity is verified by means of the comparison between the stator phase current harmonics of the simulating wave and those of the experiment wave. Air gap flux density is calculated by means of this model and radial electromagnetic force is calculated using the classical Maxwell stress tensor method. Air gap flux density and radial electromagnetic force vary in both space domain and time domain and two dimensional Fourier analysis are carried out to calculate harmonics of those. The influence of the tooth and slot and the slip on flux density and radial electromagnetic force are discussed. The relationship of flux density waves and radial electromagnetic force waves are analyzed. Radial electromagnetic force waves and the testing electromagnetic noise spectra are analyzed and compared and the results verify the effectiveness of the calculation of radial electromagnetic force waves. Radial electromagnetic force and its harmonics calculated by the method can be used to electromagnetic noise analysis in the design stage.%建立笼型异步电动机的场路耦合时步有限元模型,通过定子相电流仿真波形和实测波形的谐波比较验证有效性。基于该模型计算气隙磁通密度,进而利用经典的Maxwell应力张量法计算径向电磁力。气隙磁通密度和径向电磁力均随空间和时间变化,利用二维傅里叶分析分别求解它们的谐波;并探讨齿槽和转差率对磁通密度和径向电磁力的影响,以及磁通密度波和径向电磁力波之间的关系。将径向电磁力波和实测电磁噪声频谱进行了分析和对比,结果表明径向电磁力波的计算是合理有效的。利用本文方法计算的径向电磁力及其谐波可应用于在设计阶段对电磁噪声的分析。

  5. Labeled Postings for Asynchronous Interaction

    Science.gov (United States)

    ChanLin, Lih-Juan; Chen, Yong-Ting; Chan, Kung-Chi

    2009-01-01

    The Internet promotes computer-mediated communications, and so asynchronous learning network systems permit more flexibility in time, space, and interaction than synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online…

  6. ASCERTAINMENT OF THE EQUIVALENT CIRCUIT PARAMETERS OF THE ASYNCHRONOUS MACHINE

    Directory of Open Access Journals (Sweden)

    V. S. Safaryan

    2015-01-01

    Full Text Available The article considers experimental and analytical determination of the asynchronous machine equivalent-circuit parameters with application of the reference data. Transient processes investigation of the asynchronous machines necessitates the equivalent circuit parameters (resistance impedance, inductances and coefficient of the stator-rotor contours mutual inductance that help form the transitory-process mathematical simulation model. The reference books do not provide those parameters; they instead give the rated ones (active power, voltage, slide, coefficient of performance and capacity coefficient as well as the ratio of starting and nominal currents and torques. The noted studies on the asynchronous machine equivalent-circuits parametrization fail to solve the problems ad finem or solve them with admissions. The paper presents experimental and analytical determinations of the asynchronous machine equivalent-circuit parameters: the experimental one based on the results of two measurements and the analytical one where the problem boils down to solving a system of nonlineal algebraic equations. The authors investigate the equivalent asynchronous machine input-resistance properties and adduce the dependence curvatures of the input-resistances on the slide. They present a symbolic model for analytical parameterization of the asynchronous machine equivalent-circuit that represents a system of nonlineal equations and requires one of the rotor-parameters arbitrary assignment. The article demonstrates that for the asynchronous machine equivalent-circuit experimental parameterization the measures are to be conducted of the stator-circuit voltage, current and active power with two different slides and arbitrary assignment of one of the rotor parameters. The paper substantiates the fact that additional measurement does not discard the rotor-parameter choice arbitrariness. The authors establish that in motoring mode there is a critical slide by which the

  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. Research on the mechanism of improving the startup performance to the deep grooves on double cage asynchronous motors%深槽式双笼型异步电动机启动性能改善的机理研究

    Institute of Scientific and Technical Information of China (English)

    黄加明

    2016-01-01

    在深槽式双笼异步电动机启动时,利用转子电流的“集肤效应”可使等效电阻增大、启动电流降低、启动转矩增大,从而改善启动性能。同时,随着转速的上升,转子频率降低、转子等效电阻无级减小,这使得电机启动平滑稳定。%The improvement on the startup performance to the deep grooves on double cage asynchronous motors is introduced. When starting double cage induction motor, the rotor current uses the “skin effect” to make the rotor equivalent resistance increase, so the the starting current is reduced and the starting torque is increased, thus to improve the startup performance of the motor. With the increasing of the rotational speed, the rotor frequency is decreased, the rotor equivalent resistance is stepless reduced, and the smoothly startup of the motor is achieved.

  9. ZONES OF STEADY CAPACITOR EXCITATION IN A MODE OF GENERATION OF TYPICAL ASYNCHRONOUS MACHINES

    Directory of Open Access Journals (Sweden)

    Postoronca Sv.

    2009-12-01

    Full Text Available In work some features of a mode of capacitor excitation of industrial asynchronous electric motors, and also generators made on their base which can be used in wind installations of low power are considered. Borders of zones of steady capacitor excitation of asynchronous electric motors in rated power of 0,25-22,0 kW and generators made on their base, and also character of influence of own losses and active capacity of loading of the equivalent circuit of the asynchronous machine resulted in parameters have been determined. Some recommendations after maintenance of stability of capacitor excitation of asynchronous machines for work in a mode of generation of electric energy are given.

  10. Asynchronous Bounded Expected Delay Networks

    CERN Document Server

    Bakhshi, Rena; 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 contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).

  11. 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

  12. Research of Asynchronous Motor Torque Ramp Current Limiting Start Based on dsPIC30 F6014 A%基于dsPIC30 F6014 A的异步电机转矩斜坡限流起动研究∗

    Institute of Scientific and Technical Information of China (English)

    刘斌; 童军; 曹浩翔; 王侠辉

    2016-01-01

    The mathematical model of the T-type equivalent circuit of induction motor was analyzed and studied, the control method of the asynchronous motor torque ramp current limiting was proposed, the fuzzy PID adaptive control was used in the current limiting control section. On the basis of this theory, using the MATLAB/Simulink tool to construct the simulation platform, the soft start of the motor torque limiting control was carried out. The result showed that this method could improved the starting torque of the starting current of the motor, so the reliability of the theory of the limit flow of the torque and the slope was verified.%对异步电机的T型等效电路的数学模型进行分析与研究,提出了异步电机转矩斜坡限流起动的控制思路,并将模糊PID自适应控制思路运用在限流控制部分。在此理论基础下,利用MATLAB/Simulink工具构建仿真平台对电机转矩限流控制的软起动进行试验。试验结果说明,该方法在降低电机起动电流的同时还可以提高起动转矩,从而验证了转矩斜坡限流理论的可靠性。

  13. Asymptotic behavior of asynchronous stochasticapproximation

    Institute of Scientific and Technical Information of China (English)

    方海涛; 陈翰馥

    2001-01-01

    The pathwise convergence of a distributed, asynchronous stochastic approximation (SA) scheme is analyzed. The conditions imposed on the step size and noise are the weakest in comparison with the existing ones. The step sizes in different processors are allowed to be different, and the time_delays between processors are also allowed to be different and even time_varying.

  14. 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…

  15. 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

  16. 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 ...

  17. GAMIFICATION IN ASYNCHRONOUS EDUCATION PROCESS

    Directory of Open Access Journals (Sweden)

    B. P. Dyakonov

    2016-01-01

    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.

  18. 电动汽车用异步电机驱动控制系统可靠性分析%Reliability Analysis of Asynchronous Motors Driving and Controlling System in Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    李强; 王永全; 付瑶琴

    2014-01-01

    电机驱动控制系统是电动汽车的心脏,其可靠性直接影响着电动汽车的安全性。分析了驱动控制系统的主要故障模式,其薄弱环节为电机轴承系统、绝缘系统,及直流母线电容、IGBT等电子元器件。在此基础上建立可靠性模型。采用元器件应力分析法预计电动汽车电机驱动系统的可靠性。%The motor driving and controlling system is the heart of the electric vehicle, whose reliability directly affects the safety of the electric vehicle. The main failure pattern of the motor driving and controlling system was analyzed, in which the motor bearing systems, insulation systems, DC bus capacitors, IGBT and other electronic components are the weak links. On the basis of the analysis, the reliability model was established. Based on the established reliability model, the reliability of motor driving and controlling system in electric vehicles was estimated by the component stress analysis method.

  19. 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)

  20. How to Use the Slot-corresponding to-phase Diagram Method to Design the Single/Double-speed Winding in the 3-phase Asynchronous Motor%如何用槽号相位图法设计三相异步电动机单、双速绕组

    Institute of Scientific and Technical Information of China (English)

    吴丹; 曹亭; 吴琴琴

    2014-01-01

    槽号相位图法主要是用来研究三相单速及双速交流电动机中电枢绕组的排列方法。槽号相位图法与传统的槽电势排列表和槽矢量星形图相比,能做到槽号分配、相位关系及连接方法等在一张图上表示出来。%The slot-corresponding to-phase diagram method was used to study the armature winding arrange-ment of the single/double-speed windings in the 3-phase asynchronous motor. Compared with the slot-corresponding to-phase diagram method against traditional slot potential list or slot vector-star diagram method, the slot-correspond-ing to-phase diagram method was able to show the slot No. distribution, phase relationship and connection&wiring on the same list.

  1. Thyristor-based three-phase asynchronous motor soft start research%基于晶闸管软起动的三相异步电动机的研究

    Institute of Scientific and Technical Information of China (English)

    袁帆

    2013-01-01

    This article discusses the use of Thyristor firing angle changed to adjust the voltage across the induction motor stator, thereby changing the motor speed and stator current soft start works. This soft-start mode structure is simple、excellent performance and is easy to be adjusted. For less demanding fan and pump load is very applicable.%文章论述了利用改变晶闸管的触发角来调节异步电动机定子两端电压,进而改变电机的转速和定子电流的软起动的原理。这种软起动方式结构简单,性能好,调试容易,对于要求不高的风机、泵类负载非常适用。

  2. Asynchronous Learning Forums for Business Acculturation

    Science.gov (United States)

    Pence, Christine Cope; Wulf, Catharina

    2009-01-01

    The use of IT as a facilitator for student collaboration in higher business education has grown rapidly since 2000. Asynchronous discussion forums are used abundantly for collaborative training purposes and for teaching students business-relevant tools for their future careers. This article presents an analysis of the asynchronous discussion forum…

  3. Commande adaptive d'une machine asynchrone

    Science.gov (United States)

    Slama-Belkhodja, I.; de Fornel, B.

    1996-06-01

    The paper deals with an indirect self-tuning speed control for an induction motor supplied by a chopper-filter-inverter system. Input/Output models are identified with the recursive least squares algorithm and the controller adaptation is based on a pole assignement strategy. Emphasis is put on the evaluation of the parameter identification in order to avoid instabilities because of disturbances or insufficient excitations. This is especially of importance when the adaptive control is carried out in closed loop systems and without additional test signals. Simulation results show the improvement of the dynamic responses and the robustness against load variations or parameters variations (rotor resistance, inertia). Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation et de la nature peu riche en excitations des entrées du processus. Différents régimes transitoires ont été simulés pour apprécier l'apport de cette association (MCR-PP) : démarrages et inversion des sens de rotation, à vide et en charges, applications d'échelons de couple résistant, variations paramétriques. Les résultats permettent d'illustrer, tant au niveau des performances que de la robustesse, l'apport d'une telle commande adaptive pour des entraînements électriques avec une machine asynchrone.

  4. 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.

  5. RBF神经网络在异步电机故障诊断中的应用%The Applications of the RBP Nerve Network in the Fault Diagnosis to the Asynchronous Motor

    Institute of Scientific and Technical Information of China (English)

    穆丽娟; 苏晓娜; 李晓明

    2012-01-01

    This paper applies RBF neural network into the fault diagnosis of motor and constructs the RBF fault diagnosis model of motor. To overcome the limitations of RBF neural network, differential evolutionary algorithm is imported into this paper. The universal search ability of DE algorithm could help us to optimize center, width of basic function and network float weight of RBF neural network, and build the most suitable network model. The experimental result shows that the optimized RBF neural network' s generalization ability and diagnosis accuracy have be substantially improved.%将径向基(RBF)神经网络应用到电机的故障诊断中,建立了异步电机的RBF神经网络诊断模型.为了克服RBF神经网络学习算法的不足,引入了差分进化(DE)算法,并且利用了差分进化(DE)算法的全局搜索能力来优化RBF神经网络基函数的中心、宽度以及网络的连接权值,以获得最优的网络模型.仿真结果表明优化后的RBF神经网络的泛化能力和诊断精度都得到了大幅度提高.

  6. 三相异步电机空载试验特性曲线拟合%Characteristic curve-fitting of ho-load test for three-phase asynchronous motor

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 郭颖达; 王志芳

    2011-01-01

    Data processing of motor type test has a problem of low precision of curve-fitting. This paper proposed a curve-fitting function and made a detailed discussion on how to discriminate original data and the function that fits no-load test. VC++ language is adopted to realize data discrimination and draw a characteristic curve of high precision.%针对处理电机试验数据时曲线拟合精度低的情况,提出了空载试验的拟合函数.详细讨论了对原始数据的甄别,以及适用于空载试验的函数,采用VC++实现数据甄别,绘制精度高的特性曲线.

  7. Industrial electric motors; Moteurs electriques industriels

    Energy Technology Data Exchange (ETDEWEB)

    Maye, P.

    2005-08-15

    This book makes a synthesis of the present day knowledge on electric motors as main industrial applications of energy conversion. It explains the basic principles and the main physical laws controlling their operation. It describes with details the different types of motors with their utilization: the asynchronous motor (the most common AC motor), the synchronous motor with its 2 versions (winded for high powers and with magnets for high efficiency drives), the variable reluctance motor (promising and still under development), and the DC motor. (J.S.)

  8. Direct Torque Control of Asynchronism Motor Based on Space Vector Pulse Width Modulation%基于SVPWM的感应电机直接转矩控制方法的研究

    Institute of Scientific and Technical Information of China (English)

    高中臣; 张爱玲; 陈晨

    2009-01-01

    To reduce the low speed torque ripple of induction motor and keep constant switch frequency, this paper proposed a new control strategy on the basis of direct torque control (DTC),which uses Space Vector Pulse Width Modulation instead of switch table.The experiment and simulation results show that it can reduce the torque ripple,and improve the waveform of stator flux and current.%针对传统直接转矩控制开关频率不恒定及低速时的转矩脉动大的缺点,采用了基于SVPWM的直接转矩控制方法.根据转矩和定子磁链的误差确定应该施加的参考电压矢量,然后利用电压空间矢量脉宽调制(SVPWM)的方法合成该矢量.仿真和实验结果表明,基于SVPWM的直接转矩控制(SVPWM-DTC)能够有效减小转矩脉动,改善磁链和电流波形.

  9. 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。

  10. Asynchronous design of Networks-on-Chip

    DEFF Research Database (Denmark)

    Sparsø, Jens

    2007-01-01

    The Network-on-chip concept has evolved as a solution to a broad range of problems related to the design of complex systems-on-chip (SoC) with tenths or hundreds of (heterogeneous) IP-cores. The paper introduces the NoC concept, identifies a range of possible timing organizations (globally......-synchronous, mesochronous, globally-asynchronous locally-synchronous and fully asynchronous), discusses the circuitry needed to implement these timing methodologies, and provides some implementation details for a couple of asynchronous NoCs designed at the Technical University of Denmark (DTU). The paper is written...

  11. 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.

  12. Asynchronous networks and event driven dynamics

    Science.gov (United States)

    Bick, Christian; Field, Michael

    2017-02-01

    Real-world networks in technology, engineering and biology often exhibit dynamics that cannot be adequately reproduced using network models given by smooth dynamical systems and a fixed network topology. Asynchronous networks give a theoretical and conceptual framework for the study of network dynamics where nodes can evolve independently of one another, be constrained, stop, and later restart, and where the interaction between different components of the network may depend on time, state, and stochastic effects. This framework is sufficiently general to encompass a wide range of applications ranging from engineering to neuroscience. Typically, dynamics is piecewise smooth and there are relationships with Filippov systems. In this paper, we give examples of asynchronous networks, and describe the basic formalism and structure. In the following companion paper, we make the notion of a functional asynchronous network rigorous, discuss the phenomenon of dynamical locks, and present a foundational result on the spatiotemporal factorization of the dynamics for a large class of functional asynchronous networks.

  13. Asynchronous stochastic approximation with differential inclusions

    Directory of Open Access Journals (Sweden)

    David S. Leslie

    2012-01-01

    Full Text Available The asymptotic pseudo-trajectory approach to stochastic approximation of Benaïm, Hofbauer and Sorin is extended for asynchronous stochastic approximations with a set-valued mean field. The asynchronicity of the process is incorporated into the mean field to produce convergence results which remain similar to those of an equivalent synchronous process. In addition, this allows many of the restrictive assumptions previously associated with asynchronous stochastic approximation to be removed. The framework is extended for a coupled asynchronous stochastic approximation process with set-valued mean fields. Two-timescales arguments are used here in a similar manner to the original work in this area by Borkar. The applicability of this approach is demonstrated through learning in a Markov decision process.

  14. Asynchronous P300-Based Brain-Computer Interface to Control a Virtual Environment : Initial Tests on End Users

    NARCIS (Netherlands)

    Aloise, Fabio; Schettini, Francesca; Arico, Pietro; Salinari, Serenella; Guger, Christoph; Rinsma, Johanna; Aiello, Marco; Mattia, Donatella; Cincotti, Febo

    2011-01-01

    Motor disability and/or ageing can prevent individuals from fully enjoying home facilities, thus worsening their quality of life. Advances in the field of accessible user interfaces for domotic appliances can represent a valuable way to improve the independence of these persons. An asynchronous P300

  15. Asynchronous P300-based brain-computer interface to control a virtual environment: initial tests on end users.

    Science.gov (United States)

    Aloise, Fabio; Schettini, Francesca; Aricò, Pietro; Salinari, Serenella; Guger, Christoph; Rinsma, Johanna; Aiello, Marco; Mattia, Donatella; Cincotti, Febo

    2011-10-01

    Motor disability and/or ageing can prevent individuals from fully enjoying home facilities, thus worsening their quality of life. Advances in the field of accessible user interfaces for domotic appliances can represent a valuable way to improve the independence of these persons. An asynchronous P300-based Brain-Computer Interface (BCI) system was recently validated with the participation of healthy young volunteers for environmental control. In this study, the asynchronous P300-based BCI for the interaction with a virtual home environment was tested with the participation of potential end-users (clients of a Frisian home care organization) with limited autonomy due to ageing and/or motor disabilities. System testing revealed that the minimum number of stimulation sequences needed to achieve correct classification had a higher intra-subject variability in potential end-users with respect to what was previously observed in young controls. Here we show that the asynchronous modality performed significantly better as compared to the synchronous mode in continuously adapting its speed to the users' state. Furthermore, the asynchronous system modality confirmed its reliability in avoiding misclassifications and false positives, as previously shown in young healthy subjects. The asynchronous modality may contribute to filling the usability gap between BCI systems and traditional input devices, representing an important step towards their use in the activities of daily living.

  16. 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

  17. 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.

  18. Adaptive Feedback Linearization Control for Asynchronous Machine with Nonlinear for Natural Dynamic Complete Observer

    Science.gov (United States)

    Bentaallah, Abderrahim; Massoum, Ahmed; Benhamida, Farid; Meroufel, Abdelkader

    2012-03-01

    This paper studies the nonlinear adaptive control of an induction motor with natural dynamic complete nonlinear observer. The aim of this work is to develop a nonlinear control law and adaptive performance for an asynchronous motor with two main objectives: to improve the continuation of trajectories and the stability, robustness to parametric variations and disturbances rejection. This control law will independently control the speed and flux into the machine by restricting supply. A complete nonlinear observer for dynamic nature ensuring closed loop stability of the entire control and observer has been developed. Several simulations have also been carried out to demonstrate system performance.

  19. Energy-saving motor; Energiesparmotor

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M.

    2002-07-01

    This report for the Swiss Federal Office of Energy (SFOE) describes the development and testing of an advanced electrical motor using a permanent-magnet rotor. The aims of the project - to study the technical feasibility and market potential of the Eco-Motor - are discussed and the three phases of the project described. These include the calculation and realisation of a 250-watt prototype operating at 230 V, the measurement of the motor's characteristics as well as those of a comparable asynchronous motor on the test bed at the University of Applied Science in Lucerne, Switzerland, and a market study to establish if the Eco-Motor and its controller can compete against normal asynchronous motors. Also, the results of an analysis of the energy-savings potential is made, should such Eco-Motors be used. Detailed results of the three phases of the project are presented and the prospects of producing such motors in Switzerland for home use as well as for export are examined.

  20. Existence test for asynchronous interval iterations

    DEFF Research Database (Denmark)

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

    1997-01-01

    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...

  1. A Provably Secure Asynchronous Proactive RSA Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; LI Qiang; CHEN Ke-fei

    2005-01-01

    The drawback of the first asynchronous proactive RSA scheme presented by Zhou in 2001, is that the se curity definition and security proof do not follow the approach of provable security. This paper presented a provably secure asynchronous proactive RSA scheme, which includes three protocols: initial key distribution protocol,signature generation protocol and share refreshing protocol. Taken these protocols together, a complete provably secure proactive RSA scheme was obtained. And the efficiency of the scheme is approximate to that of the scheme of Zhou.

  2. Processor arrays with asynchronous TDM optical buses

    Science.gov (United States)

    Li, Y.; Zheng, S. Q.

    1997-04-01

    We propose a pipelined asynchronous time division multiplexing optical bus. Such a bus can use one of the two hardwared priority schemes, the linear priority scheme and the round-robin priority scheme. Our simulation results show that the performances of our proposed buses are significantly better than the performances of known pipelined synchronous time division multiplexing optical buses. We also propose a class of processor arrays connected by pipelined asynchronous time division multiplexing optical buses. We claim that our proposed processor array not only have better performance, but also have better scalabilities than the existing processor arrays connected by pipelined synchronous time division multiplexing optical buses.

  3. Synchronization of Asynchronous Switched Boolean Network.

    Science.gov (United States)

    Zhang, Hao; Wang, Xingyuan; Lin, Xiaohui

    2015-01-01

    In this paper, the complete synchronizations for asynchronous switched Boolean network with free Boolean sequence controllers and close-loop controllers are studied. First, the basic asynchronous switched Boolean network model is provided. With the method of semi-tensor product, the Boolean dynamics is translated into linear representation. Second, necessary and sufficient conditions for ASBN synchronization with free Boolean sequence control and close-loop control are derived, respectively. Third, some illustrative examples are provided to show the efficiency of the proposed methods.

  4. A simple asynchronous replica-exchange implementation

    CERN Document Server

    Bussi, Giovanni

    2008-01-01

    We discuss the possibility of implementing asynchronous replica-exchange (or parallel tempering) molecular dynamics. In our scheme, the exchange attempts are driven by asynchronous messages sent by one of the computing nodes, so that different replicas are allowed to perform a different number of time-steps between subsequent attempts. The implementation is simple and based on the message-passing interface (MPI). We illustrate the advantages of our scheme with respect to the standard synchronous algorithm and we benchmark it for a model Lennard-Jones liquid on an IBM-LS21 blade center cluster.

  5. 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...

  6. Asynchronous ASCII Event Count Status Code

    Science.gov (United States)

    2012-03-01

    IRIG STANDARD 215-12 TELECOMMUNICATIONS AND TIMING GROUP ASYNCHRONOUS ASCII EVENT COUNT STATUS CODES...Inter-range Instrumentation Group ( IRIG ) Standard for American Standard Code for Information Interchange (ASCII)-formatted EC status transfer which can be...circuits and Ethernet networks. Provides systems engineers and equipment vendors with an Inter-range Instrumentation Group ( IRIG ) Standard for American

  7. 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…

  8. Asynchronous stream processing with S-Net

    NARCIS (Netherlands)

    Grelck, C.; Scholz, S.-B.; Shafarenko, A.

    2010-01-01

    We present the rationale and design of S-Net, a coordination language for asynchronous stream processing. The language achieves a near-complete separation between the application code, written in any conventional programming language, and the coordination/communication code written in S-Net. Our app

  9. 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.

  10. 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

  11. 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.

  12. Low Latency High Throughout Circular Asynchronous FIFO

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong; ZHOU Runde

    2008-01-01

    This paper describes a circular first in first out (FIFO) and its protocols which have a very low la-tency while still maintaining high throughput. Unlike the existing serial FIFOs based on asynchronous micro-pipelines, this FIFO's cells communicate directly with the input and output ports through a common bus, which effectively eliminates the data movement from the input port to the output port, thereby reducing the latency and the power consumption. Furthermore, the latency does not increase with the number of FIFO stages. Single-track asynchronous protocols are used to simplify the FIFO controller design, with only three C-gates needed in each cell controller, which substantially reduces the area. Simulations with the TSMC 0.25 Ijm CMOS logic process show that the latency of the 4-stage FIFO is less than 581 ps and the throughput is higher than 2.2 GHz.

  13. 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.

  14. Linear Motor for Drive of Belt Conveyor

    Directory of Open Access Journals (Sweden)

    Milan Krasl

    2006-01-01

    Full Text Available This paper introduces a novel approach on the design of a linear motor for drive of belt conveyor (LMBC. The motor is a simple combination of asynchronous motor in plane. The electromagnetic forces is one of the most important parameters of electrical machines. This parameter is necessary for the checking of the design. This paper describes several variants: linear motor with slots in platens, slots in one half of platens and optimization of slots. The electromagnetic force can be found with the help of a Finite Elements Method – based program. For solution was used QuickField program.

  15. Asynchronous exponential growth of a bacterial population

    Directory of Open Access Journals (Sweden)

    Mohamed Boulanouar

    2014-01-01

    Full Text Available In this work, we complete a study started earlier in [1,2] wherein a model of growing bacterial population has been the matter of a mathematical analysis. We show that the full model is governed by a strongly continuous semigroup. Beside the positivity and the irreducibility of the generated semigroup, we describe its asymptotic behavior in the uniform topology which leads to the asynchronous exponential growth of the bacterial population.

  16. 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.

  17. Asynchronous event-based binocular stereo matching.

    Science.gov (United States)

    Rogister, Paul; Benosman, Ryad; Ieng, Sio-Hoi; Lichtsteiner, Patrick; Delbruck, Tobi

    2012-02-01

    We present a novel event-based stereo matching algorithm that exploits the asynchronous visual events from a pair of silicon retinas. Unlike conventional frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of the biological retina. Our algorithm uses the timing information carried by this representation in addressing the stereo-matching problem on moving objects. Using the high temporal resolution of the acquired data stream for the dynamic vision sensor, we show that matching on the timing of the visual events provides a new solution to the real-time computation of 3-D objects when combined with geometric constraints using the distance to the epipolar lines. The proposed algorithm is able to filter out incorrect matches and to accurately reconstruct the depth of moving objects despite the low spatial resolution of the sensor. This brief sets up the principles for further event-based vision processing and demonstrates the importance of dynamic information and spike timing in processing asynchronous streams of visual events.

  18. 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.

  19. FPGA Architecture for Multi-Style Asynchronous Logic

    CERN Document Server

    Huot, N; Fesquet, L; Renaudin, M

    2011-01-01

    This paper presents a novel FPGA architecture for implementing various styles of asynchronous logic. The main objective is to break the dependency between the FPGA architecture dedicated to asynchronous logic and the logic style. The innovative aspects of the architecture are described. Moreover the structure is well suited to be rebuilt and adapted to fit with further asynchronous logic evolutions thanks to the architecture genericity. A full-adder was implemented in different styles of logic to show the architecture flexibility.

  20. 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

  1. Synchronous motor with hybrid permanent magnets on the rotor.

    Science.gov (United States)

    Slusarek, Barbara; Kapelski, Dariusz; Antal, Ludwik; Zalas, Pawel; Gwoździewicz, Maciej

    2014-07-10

    Powder metallurgy allows designers of electric motors to implement new magnetic circuit structures. A relatively new concept is the use of a magnet system consisting of various types of magnets on one rotor, for example sintered and bonded magnets. This concept has been applied to the design and manufacture of the four-pole rotor of a synchronous motor with 400 W power and a rotational speed of 1500 rpm. In this motor, the stator of an asynchronous motor type Sh 71-4B is applied. The application of the new construction of the rotor resulted in an increase in motor efficiency and power factor compared to an asynchronous motor with the same volume.

  2. 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...

  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 Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-08-30

    We present, in a unifying way, the main components of three asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel stochastic molecular-dynamics algorithm that builds on the Direct Simulation Monte Carlo (DSMC). We explain how to effectively combine event-driven and classical time-driven handling, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  5. Asynchronous Event-Driven Particle Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A

    2007-02-28

    We present in a unifying way the main components of three examples of asynchronous event-driven algorithms for simulating physical systems of interacting particles. The first example, hard-particle molecular dynamics (MD), is well-known. We also present a recently-developed diffusion kinetic Monte Carlo (DKMC) algorithm, as well as a novel event-driven algorithm for Direct Simulation Monte Carlo (DSMC). Finally, we describe how to combine MD with DSMC in an event-driven framework, and discuss some promises and challenges for event-driven simulation of realistic physical systems.

  6. Globally coupled maps with asynchronous updating

    CERN Document Server

    Abramson, G; Abramson, Guillermo; Zanette, Damian H.

    1998-01-01

    We analyze a system of globally coupled logistic maps with asynchronous updating. We show that its dynamics differs considerably from that of the synchronous case. For growing values of the coupling intensity, an inverse bifurcation cascade replaces the structure of clusters and ordering in the phase diagram. We present numerical simulations and an analytical description based on an effective single-element dynamics affected by internal fluctuations. Both of them show how global coupling is able to suppress the complexity of the single-element evolution. We find that, in contrast to systems with synchronous update, internal fluctuations satisfy the law of large numbers.

  7. Two Studies Examining Argumentation in Asynchronous Computer Mediated Communication

    Science.gov (United States)

    Joiner, Richard; Jones, Sarah; Doherty, John

    2008-01-01

    Asynchronous computer mediated communication (CMC) would seem to be an ideal medium for supporting development in student argumentation. This paper investigates this assumption through two studies. The first study compared asynchronous CMC with face-to-face discussions. The transactional and strategic level of the argumentation (i.e. measures of…

  8. 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…

  9. 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.

  10. ASYNCHRONOUS BYZANTINE AGREEMENT PROTOCOL BASED ON VERIFIABLE SIGNATURE SHARING

    Institute of Scientific and Technical Information of China (English)

    Ji Dongyao; Feng Dengguo

    2006-01-01

    An ([n / 3]- 1 )-resilient Asynchronous Byzantine Agreement Protocol (ABAP) that combines verifiable signature sharing and random secret sharing is proposed. The protocol works in the asynchronous network environment and produces Byzantine agreement within a fixed expected number of computational rounds. The correctness of the protocol is proved in theory.

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

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1999-01-01

    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 broader......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 same 0.7 /spl mu/m CMOS technology. When processing typical data (less than 50 dB sound pressure), the asynchronous control and data-path logic, an improved RAM design, and by a mechanism that adapts the number range to the actual need (exploiting the fact that typical audio signals are characterized...

  12. Asynchronicity of facial blood perfusion in migraine.

    Directory of Open Access Journals (Sweden)

    Nina Zaproudina

    Full Text Available Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  13. Asynchronicity of facial blood perfusion in migraine.

    Science.gov (United States)

    Zaproudina, Nina; Teplov, Victor; Nippolainen, Ervin; Lipponen, Jukka A; Kamshilin, Alexei A; Närhi, Matti; Karjalainen, Pasi A; Giniatullin, Rashid

    2013-01-01

    Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI) technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  14. 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.

  15. Controllability of asynchronous Boolean multiplex control networks

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-09-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  16. Controllability of asynchronous Boolean multiplex control networks.

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-09-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) is studied. First, the model of Boolean multiplex control networks under Harvey' asynchronous update is presented. By means of semi-tensor product approach, the logical dynamics is converted into linear representation, and a generalized formula of control-depending network transition matrices is achieved. Second, a necessary and sufficient condition is proposed to verify that only control-depending fixed points of ABMCNs can be controlled with probability one. Third, using two types of controls, the controllability of system is studied and formulae are given to show: (a) when an initial state is given, the reachable set at time s under a group of specified controls; (b) the reachable set at time s under arbitrary controls; (c) the specific probability values from a given initial state to destination states. Based on the above formulae, an algorithm to calculate overall reachable states from a specified initial state is presented. Moreover, we also discuss an approach to find the particular control sequence which steers the system between two states with maximum probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  17. Resynchronization of the Asynchronous Polar CD Ind

    Science.gov (United States)

    Myers, Gordon; Patterson, Joseph; de Miguel, Enrique; Hambsch, Franz-Josef; Monard, Berto; Bolt, Greg; McCormick, Jennie; Rea, Robert; Allen, William

    2017-04-01

    CD Ind is one of only four confirmed asynchronous polars (APs). APs are strongly magnetic cataclysmic variables of the AM Herculis subclass with the characteristic that their white dwarfs rotate a few percent out of synchronism with their binary orbit. Theory suggests that nova eruptions disrupt previously synchronized states. Following the eruption, the system is expected to rapidly resynchronize over a timescale of centuries. The other three asynchronous polars—V1432 Aql, BY Cam, and V1500 Cyg—have resynchronization time estimates ranging from 100 to more than 3500 years, with all but one being less than 1200 years. We report on the analysis of over 46,000 observations of CD Ind taken between 2007 and 2016, combined with previous observations from 1996, and estimate a CD Ind resynchronization time of 6400 ± 800 years. We also estimate an orbital period of 110.820(1) minutes and a current (2016.4) white dwarf spin period of 109.6564(1) minutes.

  18. 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

  19. Commande adaptive d'une machine asynchrone

    OpenAIRE

    I. Slama-Belkhodja; De Fornel, B.

    1996-01-01

    Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation e...

  20. Implementation of Universal Asynchronous Receiver and Transmitter

    Directory of Open Access Journals (Sweden)

    Payata Srikanth Yadav

    2015-03-01

    Full Text Available Universal Asynchronous Receiver Transmitter (UART is the serial communication protocol that is used for data exchange between computer & peripherals. UART is a low velocity, short-distance, low-cost protocol. UART includes three modules which are received, the baud rate generator and transmitter. The UART design with Very High Description Language can be integrated into the Field Programmable Gate Array to achieve stable data transmission and to make system reliable and compact. In the result and simulation part, this project will focus on check the receive data with error free & baud rate generation at different frequencies. Before synthesizing of UART a baud rate generator is incorporated into the system. We use the frequency divider which sets itself to required frequency for the functionality at lower frequency. All modules are designed using VERILOG and implemented on Xilinx Suite development board.

  1. 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.

  2. Scalable asynchronous execution of cellular automata

    Science.gov (United States)

    Folino, Gianluigi; Giordano, Andrea; Mastroianni, Carlo

    2016-10-01

    The performance and scalability of cellular automata, when executed on parallel/distributed machines, are limited by the necessity of synchronizing all the nodes at each time step, i.e., a node can execute only after the execution of the previous step at all the other nodes. However, these synchronization requirements can be relaxed: a node can execute one step after synchronizing only with the adjacent nodes. In this fashion, different nodes can execute different time steps. This can be a notable advantageous in many novel and increasingly popular applications of cellular automata, such as smart city applications, simulation of natural phenomena, etc., in which the execution times can be different and variable, due to the heterogeneity of machines and/or data and/or executed functions. Indeed, a longer execution time at a node does not slow down the execution at all the other nodes but only at the neighboring nodes. This is particularly advantageous when the nodes that act as bottlenecks vary during the application execution. The goal of the paper is to analyze the benefits that can be achieved with the described asynchronous implementation of cellular automata, when compared to the classical all-to-all synchronization pattern. The performance and scalability have been evaluated through a Petri net model, as this model is very useful to represent the synchronization barrier among nodes. We examined the usual case in which the territory is partitioned into a number of regions, and the computation associated with a region is assigned to a computing node. We considered both the cases of mono-dimensional and two-dimensional partitioning. The results show that the advantage obtained through the asynchronous execution, when compared to the all-to-all synchronous approach is notable, and it can be as large as 90% in terms of speedup.

  3. Evaluating the Efficiency of Asynchronous Systems with FASE

    CERN Document Server

    Buti, Federico; Corradini, Flavio; Di Berardini, Maria Rita; Vogler, Walter

    2011-01-01

    In this paper, we present FASE (Faster Asynchronous Systems Evaluation), a tool for evaluating the worst-case efficiency of asynchronous systems. The tool is based on some well-established results in the setting of a timed process algebra (PAFAS: a Process Algebra for Faster Asynchronous Systems). To show the applicability of FASE to concrete meaningful examples, we consider three implementations of a bounded buffer and use FASE to automatically evaluate their worst-case efficiency. We finally contrast our results with previous ones where the efficiency of the same implementations has already been considered.

  4. 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.

  5. Optimum Multiuser Detector for Multipath Slow Fading Asynchronous CDMA Channels

    Institute of Scientific and Technical Information of China (English)

    WangZhaocheng; YangZhixing; 等

    1995-01-01

    A structure of optimum multiuser detector for asynchronous CDMA in multipath slow fading channels is derived and the significant performance gain over the conventional RAKE receiv-er is shown by simulation.

  6. A proof system for asynchronously communicating deterministic processes

    NARCIS (Netherlands)

    de Boer, F.S.; van Hulst, M.

    1994-01-01

    We introduce in this paper new communication and synchronization constructs which allow deterministic processes, communicating asynchronously via unbounded FIFO buffers, to cope with an indeterminate environment. We develop for the resulting parallel programming language, which subsumes deterministi

  7. 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.

  8. 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.

  9. Novel Asynchronous Wrapper and Its Application to GALS Systems

    Institute of Scientific and Technical Information of China (English)

    Zhuang Shengxian; Peng Anjin; Lars Wanhammar

    2006-01-01

    An asynchronous wrapper with novel handshake circuits for data communication in globally asynchronous locally synchronous (GALS) systems is proposed. The handshake circuits include two communication ports and a local clock generator. Two approaches for the implementation of communication ports are presented, one with pure standard cells and the others with Müller-C elements. The detailed design methodology for GALS systems is given and the circuits are validated with VHDL and circuits simulation in standard CMOS technology.

  10. Experimental 3D Asynchronous Field Programmable Gate Array (FPGA)

    Science.gov (United States)

    2015-03-01

    EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) CORNELL UNIVERSITY MARCH 2015 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC...From - To) OCT 2011 – OCT 2014 4. TITLE AND SUBTITLE EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) 5a. CONTRACT NUMBER...in collaboration with Albany’s College of Nanoscale Science and Engineering. 15. SUBJECT TERMS 3D Technology, vertical interconnects, AFPGA, FPGA

  11. MODIFIED MICROPIPLINE ARCHITECTURE FOR SYNTHESIZABLE ASYNCHRONOUS FIR FILTER DESIGN

    Directory of Open Access Journals (Sweden)

    Basel Halak

    2016-02-01

    Full Text Available The use of asynchronous design approaches to construct digital signal processing (DSP systems is a rapidly growing research area driven by a wide range of emerging energy constrained applications such as wireless sensor network, portable medical devices and brain implants. The asynchronous design techniques allow the construction of systems which are samples driven, which means they only dissipate dynamic energy when there processing data and idle otherwise. This inherent advantage of asynchronous design over conventional synchronous circuits allows them to be energy efficient. However the implementation flow of asynchronous systems is still difficult due to its lack of compatibility with industrystandard synchronous design tools and modelling languages. This paper devises a novel asynchronous design for a finite impulse response (FIR filter, an essential building block of DSP systems, which is synthesizable and suitable for implementation using conventional synchronous systems design flow and tools. The proposed design is based on a modified version of the micropipline architecture and it is constructed using four phase bundled data protocol. A hardware prototype of the proposed filter has been developed on an FPGA, and systematically verified. The results prove correct functionality of the novel design and a superior performance compared to a synchronous FIR implementation. The findings of this work will allow a wider adoption of asynchronous circuits by DSP designers to harness their energy and performance benefits.

  12. Research and development of forced air cooling lfat type three-phase straight line asynchronous motor cooling system%强迫风冷扁平型三相直线异步电动机冷却系统的研发

    Institute of Scientific and Technical Information of China (English)

    宋文芳

    2013-01-01

    The cooling system of linear induction motor for metro vehicle is researched and developed. It describes the cooling method of forced air linear motor, cooling structure and work principle to ifll the domestic blank.%研发了一种牵引轨道交通车辆用直线电机的冷却系统,阐述强迫风冷直线电机的冷却方式、冷却结构和工作原理,填补了国内空白。

  13. 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.

  14. Asynchronous Rate Chaos in Spiking Neuronal Circuits

    Science.gov (United States)

    Harish, Omri; Hansel, David

    2015-01-01

    The brain exhibits temporally complex patterns of activity with features similar to those of chaotic systems. Theoretical studies over the last twenty years have described various computational advantages for such regimes in neuronal systems. Nevertheless, it still remains unclear whether chaos requires specific cellular properties or network architectures, or whether it is a generic property of neuronal circuits. We investigate the dynamics of networks of excitatory-inhibitory (EI) spiking neurons with random sparse connectivity operating in the regime of balance of excitation and inhibition. Combining Dynamical Mean-Field Theory with numerical simulations, we show that chaotic, asynchronous firing rate fluctuations emerge generically for sufficiently strong synapses. Two different mechanisms can lead to these chaotic fluctuations. One mechanism relies on slow I-I inhibition which gives rise to slow subthreshold voltage and rate fluctuations. The decorrelation time of these fluctuations is proportional to the time constant of the inhibition. The second mechanism relies on the recurrent E-I-E feedback loop. It requires slow excitation but the inhibition can be fast. In the corresponding dynamical regime all neurons exhibit rate fluctuations on the time scale of the excitation. Another feature of this regime is that the population-averaged firing rate is substantially smaller in the excitatory population than in the inhibitory population. This is not necessarily the case in the I-I mechanism. Finally, we discuss the neurophysiological and computational significance of our results. PMID:26230679

  15. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Leggett, Charles; 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...

  16. 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.

  17. 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

  18. Asynchronous reference frame agreement in a quantum network

    Science.gov (United States)

    Islam, Tanvirul; Wehner, Stephanie

    2016-03-01

    An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

  19. 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 creating truly...... continuous time asynchronous circuits that operate without a clock. The perspective here is that the substitution/conversion is done as the final step in an otherwise conventional synchronous design flow....

  20. 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

    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 ..., we show that such an input-distribution oracle can be reduced to an oracle that allows each party to synchronously broadcast one single message. This means that when one single round of synchronous broadcast is available, then asynchronous MPC is possible at the same condition as synchronous MPC...

  1. Design issues in the semantics and scheduling of asynchronous tasks.

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, Stephen L.

    2013-07-01

    The asynchronous task model serves as a useful vehicle for shared memory parallel programming, particularly on multicore and manycore processors. As adoption of model among programmers has increased, support has emerged for the integration of task parallel language constructs into mainstream programming languages, e.g., C and C++. This paper examines some of the design decisions in Cilk and OpenMP concerning semantics and scheduling of asynchronous tasks with the aim of informing the efforts of committees considering language integration, as well as developers of new task parallel languages and libraries.

  2. Asynchronous Broadcast on the Intel SCC using Interrupts

    OpenAIRE

    Petrović, Darko; Shahmirzadi, Omid; Ropars, Thomas; Schiper, André

    2012-01-01

    International audience; This paper focuses on the design of an asynchronous broadcast primitive on the Intel SCC. Our solution is based on OC-Bcast, a state-of-the-art k-ary tree synchronous broadcast algorithm that leverages the parallelism provided by on-chip Remote Memory Accesses to Message Passing Buffers. In the paper, we study the use of parallel inter-core interrupts as a means to implement an efficient asynchronous group communication primitive, and present the userspace library we d...

  3. 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...

  4. 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.

  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. Principles for Effective Asynchronous Online Instruction in Religious Studies

    Science.gov (United States)

    McGuire, Beverley

    2017-01-01

    Asynchronous online instruction has become increasingly popular in the field of religious studies. However, despite voluminous research on online learning in general and numerous articles on online theological instruction, there has been little discussion of how to effectively design and deliver online undergraduate courses in religious studies.…

  7. 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...

  8. Chaos begets order: asynchronous cell contractions drive epithelial morphogenesis.

    Science.gov (United States)

    Paluch, Ewa; Heisenberg, Carl-Philipp

    2009-01-01

    Apical cell contraction triggers tissue folding and invagination in epithelia. During Drosophila gastrulation, ventral furrow formation was thought to be driven by smooth, purse-string-like constriction of an acto-myosin belt underlying adherens junctions. Now Martin et al. report in Nature that ventral furrow formation is triggered by asynchronous pulsed contractions of the apical acto-myosin cortex in individual cells.

  9. Online Graduate Education: Developing Scholars through Asynchronous Discussion

    Science.gov (United States)

    Bowden, Randall

    2012-01-01

    Considerable effort has been placed on understanding and enhancing online interaction to increase student learning, examine teaching strategies, and build learning communities. This research explored another aspect of interaction: the emergence of scholarship by graduate students through asynchronous discussion. Qualitative analysis of archived…

  10. 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…

  11. 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.

  12. Students' Use of Asynchronous Discussions for Academic Discourse Socialization

    Science.gov (United States)

    Beckett, Gulbahar H.; Amaro-Jimenez, Carla; Beckett, Kelvin S.

    2010-01-01

    Our universities are becoming increasingly diverse at the same time as online asynchronous discussions (OADs) are emerging as the most important forum for computer mediated communication (CMC) in distance education. But there is shortage of studies that explore how graduate students from different ethnic, linguistic and cultural backgrounds use…

  13. 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…

  14. Reconceptualising Moderation in Asynchronous Online Discussions Using Grounded Theory

    Science.gov (United States)

    Vlachopoulos, Panos; Cowan, John

    2010-01-01

    This article reports a grounded theory study of the moderation of asynchronous online discussions, to explore the processes by which tutors in higher education decide when and how to moderate. It aims to construct a theory of e-moderation based on some key factors which appear to influence e-moderation. It discusses previous research on the…

  15. 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.

  16. Asynchronous Session Types – Exceptions and Multiparty Interactions

    DEFF Research Database (Denmark)

    Carbone, Marco; Yoshida, Nobuko; Honda, Kohei

    2009-01-01

    to capture many real scenarios, there are cases where they are not powerful enough for describing and validating interactions involving more complex scenarios. In this note, we shall explore two extensions of session types to interactional exceptions and multiparty session in presence of asynchronous...

  17. RELAXED ASYNCHRONOUS ITERATIONS FOR THE LINEAR COMPLEMENTARITY PROBLEM

    Institute of Scientific and Technical Information of China (English)

    Zhong-zhi Bai; Yu-guang Huang

    2002-01-01

    We present a class of relaxed asynchronous parallel multisplitting iterative methods forsolving the linear complementarity problem on multiprocessor systems, and set up theirconvergence theories when the system matrix of the linear complementarity problem is anH-matrix with positive diagonal elements.

  18. Teachers of the Gifted: Experiences with Asynchronous Development

    Science.gov (United States)

    Rosenberg, Jennifer

    2012-01-01

    Gifted students' development is asynchronous in the social, emotional, physical and cognitive domains. Because of this, unique interventions must be used by teachers of the gifted in order to best serve their developmental and educational needs. This qualitative study used transcendental phenomenology to examine and describe the experiences…

  19. Control concept for a hybrid engine test device composed of a water vortex brake and an asynchronous machine; Regelungskonzept fuer einen Hybrid-Motorenpruefstand

    Energy Technology Data Exchange (ETDEWEB)

    Maeenpaeae, A. [ABB Automation Products, Mannheim (Germany); Fischer, G. [Technische Univ. Darmstadt (Germany)

    2000-07-01

    New environmental laws require lower exhaust limits of motor vehicles all over the world. To test these limits, drive-cycle tests are performed on engine test devices. Future laws will require the simulation od downhill driving, which requires extensive changes to the engine test devices. Hybrid test devices with a water vortex brake and an asynchronous machine could be advantageous. A new control concept for those hybrid test devices is described here. (orig.) [German] Neue Umweltgesetze druecken weltweit die Abgasgrenzwerte von Automobilen nach unten. Zur Ueberpruefung dieser Grenzwerte dienen Fahrzyklus-Testreihen auf Motorenpruefstaenden. Kuenftige Vorschriften erfordern dabei bald die Simulation des 'Schiebebetriebs' (wie bei Bergabfahrten). Das erfordert aufwendige Umruestungen bei den Motorenpruefstaenden. Eine preisguenstige Loesung stellen Hybrid-Pruefstaende aus einer Wasserwirbelbremse und einer Asynchron-Maschine dar. Ein neues Regelkonzept dafuer wird hier beschrieben. (orig.)

  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. Study of the asynchronous traction drive's operating modes by computer simulation. Part 1: Problem formulation and computer model

    Directory of Open Access Journals (Sweden)

    Pavel KOLPAHCHYAN

    2015-06-01

    Full Text Available In this paper, the problems arising from the design of electric locomotives with asynchronous traction drive (with three-phase AC induction motors are considered as including the debugging of control algorithms. The electrical circuit provides the individual (by axle control of traction motors. This allows realizing the operational disconnection/connection of one or more axles in the automatic mode, with account of actual load. In perspective, the evaluation of locomotive's energy efficiency at the realization of various control algorithms must be obtained. Another objective is to research the dynamic processes in various modes of the electric locomotive operation (start and acceleration, traction regime, coasting movement, wheel-slide protection, etc. To solve these problems, a complex computer model based on the representation of AC traction drive as controlled electromechanical system, is developed in Part 1. The description of methods applied in modeling of traction drive elements (traction motors, power converters, control systems, as well as of mechanical part and of "wheel-rail" contact, is given. The control system provides the individual control of the traction motors. Part 2 of the paper focuses on the results of dynamic processes modeling in various modes of electric locomotive operation.

  2. Students' Activity Focus in Online Asynchronous Peer Learning Forums

    Directory of Open Access Journals (Sweden)

    Naomi BOYER

    2010-04-01

    Full Text Available This qualitative study explores how using Peer Learning Forums (PLF in an online asynchronous computer programming course can be analyzed to derive information about Student Activity Focus (SAF for adult Information Technology students. Three instruments are proposed to assist instructors classify questions posted by students on these forums, obtain easy quantitative measures of their SAF, and use it to gain a better understanding of the type of learning barriers they are encountering. In addition, we also look at the difference in SAF between passing and failing students based on their exam performance. The PLF learning activity and the classification instruments are easily adaptable to other disciplines or courses and allow instructors and students alike to gain a better understanding of what kind of participation is helpful in online asynchronous discussion forums.

  3. Channel Estimation And Multiuser Detection In Asynchronous Satellite Communications

    CERN Document Server

    Chaouech, Helmi; 10.5121/ijwmn.2010.2411

    2010-01-01

    In this paper, we propose a new method of channel estimation for asynchronous additive white Gaussian noise channels in satellite communications. This method is based on signals correlation and multiuser interference cancellation which adopts a successive structure. Propagation delays and signals amplitudes are jointly estimated in order to be used for data detection at the receiver. As, a multiuser detector, a single stage successive interference cancellation (SIC) architecture is analyzed and integrated to the channel estimation technique and the whole system is evaluated. The satellite access method adopted is the direct sequence code division multiple access (DS CDMA) one. To evaluate the channel estimation and the detection technique, we have simulated a satellite uplink with an asynchronous multiuser access.

  4. Inference of asynchronous Boolean network from biological pathways.

    Science.gov (United States)

    Das, Haimabati; Layek, Ritwik Kumar

    2015-01-01

    Gene regulation is a complex process with multiple levels of interactions. In order to describe this complex dynamical system with tractable parameterization, the choice of the dynamical system model is of paramount importance. The right abstraction of the modeling scheme can reduce the complexity in the inference and intervention design, both computationally and experimentally. This article proposes an asynchronous Boolean network framework to capture the transcriptional regulation as well as the protein-protein interactions in a genetic regulatory system. The inference of asynchronous Boolean network from biological pathways information and experimental evidence are explained using an algorithm. The suitability of this paradigm for the variability of several reaction rates is also discussed. This methodology and model selection open up new research challenges in understanding gene-protein interactive system in a coherent way and can be beneficial for designing effective therapeutic intervention strategy.

  5. State assignment approach to asynchronous CMOS circuit design

    Science.gov (United States)

    Kantabutra, Vitit; Andreou, Andreas G.

    1994-04-01

    We present a new algorithm for state assignment in asynchronous circuits so that for each circuit state transition, only one (secondary) state variable switches. No intermediate unstable states are used. The resultant circuits operate at optimum speed in terms of the number of transitions made and use only static CMOS gates. By reducing the number of switching events per state transition, noise due to the switching events is reduced and dynamic power dissipation may also be reduced. Our approach is suitable for asynchronous sequential circuits that are designed from flow tables or state transition diagrams. The proposed approach may also be useful for designing synchronous circuits, but explorations into the subject of clock power would be necessary to determine its usefulness.

  6. Marine Forces Reserve: Accelerating Knowledge Flow through Asynchronous Learning Technologies

    Science.gov (United States)

    2014-12-19

    pedagogic techniques that are infeasible in the classroom , and they suggest that in some respects technologically intermediated learning can be even better...frameworks and technologies to examine I-I knowledge flows, and from the practitioner perspective, we bring to bear deep inside knowledge of the focal...ASYNCHRONOUS LEARNING TECHNOLOGIES by Mark Nissen, Robert McGuiness and Anthony Davis December 2014 Further distribution of all or part of this

  7. PersisDroid: Android Performance Diagnosis via Anatomizing Asynchronous Executions

    OpenAIRE

    Kang, Yu; Zhou, Yangfan; Xu, Hui; Lyu, Michael R.

    2015-01-01

    Android applications (apps) grow dramatically in recent years. Apps are user interface (UI) centric typically. Rapid UI responsiveness is key consideration to app developers. However, we still lack a handy tool for profiling app performance so as to diagnose performance problems. This paper presents PersisDroid, a tool specifically designed for this task. The key notion of PersisDroid is that the UI-triggered asynchronous executions also contribute to the UI performance, and hence its perform...

  8. Pipelined asynchronous time-division multiplexing optical bus

    Science.gov (United States)

    Zheng, S. Q.; Li, Yueming

    1997-12-01

    We propose a pipelined asynchronous time-division multiplexing optical bus. Such a bus can use one of two hardwared priority schemes: the linear priority scheme and the round-robin priority scheme. Our simulation results show that the performance of the proposed bus is significantly better than the performances of known pipelined synchronous time-division multiplexing optical buses. The possibilities of using our buses to construct multichannel switches and multidimensional processor arrays are also discussed.

  9. Financial Data Modeling by Using Asynchronous Parallel Evolutionary Algorithms

    Institute of Scientific and Technical Information of China (English)

    Wang Chun; Li Qiao-yun

    2003-01-01

    In this paper, the high-level knowledge of financial data modeled by ordinary differential equations (ODEs) is discovered in dynamic data by using an asynchronous parallel evolutionary modeling algorithm (APHEMA). A numerical example of Nasdaq index analysis is used to demonstrate the potential of APHEMA. The results show that the dynamic models automatically discovered in dynamic data by computer can be used to predict the financial trends.

  10. Asynchronous Transfer Mode (ATM) Switch Technology and Vendor Survey

    Science.gov (United States)

    Berry, Noemi

    1995-01-01

    Asynchronous Transfer Mode (ATM) switch and software features are described and compared in order to make switch comparisons meaningful. An ATM switch's performance cannot be measured solely based on its claimed switching capacity; traffic management and congestion control are emerging as the determining factors in an ATM network's ultimate throughput. Non-switch ATM products and experiences with actual installations of ATM networks are described. A compilation of select vendor offerings as of October 1994 is provided in chart form.

  11. Synthèse automatique de circuits asynchrones QDI

    OpenAIRE

    DINH DUC, Anh Vu

    2003-01-01

    ISBN 2-84813-010-5; Contrary to the synchronous circuits, the asynchronous circuits operate with a mechanism of local synchronization (without clock signal). Since many years, they showed their relevance with respect to the synchronous circuits thanks to their properties of robustness, low power, low noise and modularity. However, the current lack of design methods and associated tools prevents them from being widely spread. This dissertation deals with a new design methodology for quasi-dela...

  12. 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.

  13. 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.

  14. 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

    2016-04-06

    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.

  15. 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.

  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. Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

    Science.gov (United States)

    Marisa, T; Niederhauser, T; Haeberlin, A; Wildhaber, R A; Vogel, R; Goette, J; Jacomet, M

    2017-02-07

    A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing. The architecture offers the advantages of smaller chip area, energy saving and fewer analogue system components. Beside lower energy consumption the use of dynamic comparators results in a more robust performance in noise conditions. Moreover, dynamic comparators make interfacing the asynchronous level crossing system to synchronous processing blocks simpler. The proposed adc was implemented in [Formula: see text] complementary metal-oxide-semiconductor (cmos) technology, the hardware occupies a chip area of 0.0372 mm(2) and operates from a supply voltage of [Formula: see text] to [Formula: see text]. The adc's power consumption is as low as 0.6 μW with signal bandwidth from [Formula: see text] to [Formula: see text] and achieves an equivalent number of bits (enob) of up to 8 bits.

  18. A Synchronous-Asynchronous Particle Swarm Optimisation Algorithm

    Directory of Open Access Journals (Sweden)

    Nor Azlina Ab Aziz

    2014-01-01

    Full Text Available In the original particle swarm optimisation (PSO algorithm, the particles’ velocities and positions are updated after the whole swarm performance is evaluated. This algorithm is also known as synchronous PSO (S-PSO. The strength of this update method is in the exploitation of the information. Asynchronous update PSO (A-PSO has been proposed as an alternative to S-PSO. A particle in A-PSO updates its velocity and position as soon as its own performance has been evaluated. Hence, particles are updated using partial information, leading to stronger exploration. In this paper, we attempt to improve PSO by merging both update methods to utilise the strengths of both methods. The proposed synchronous-asynchronous PSO (SA-PSO algorithm divides the particles into smaller groups. The best member of a group and the swarm’s best are chosen to lead the search. Members within a group are updated synchronously, while the groups themselves are asynchronously updated. Five well-known unimodal functions, four multimodal functions, and a real world optimisation problem are used to study the performance of SA-PSO, which is compared with the performances of S-PSO and A-PSO. The results are statistically analysed and show that the proposed SA-PSO has performed consistently well.

  19. 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.

  20. 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 presented......Asynchronous circuit design is well understood but design tools supporting asynchronous design are largely lacking, and designers are limited to using conventional EDA-tools. These tools have a built-in synchronous mind-set and this complicates their use for asynchronous implementation. One example...

  1. 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.

  2. P300-based brain-computer interface for environmental control: an asynchronous approach

    Science.gov (United States)

    Aloise, F.; Schettini, F.; Aricò, P.; Leotta, F.; Salinari, S.; Mattia, D.; Babiloni, F.; Cincotti, F.

    2011-04-01

    Brain-computer interface (BCI) systems allow people with severe motor disabilities to communicate and interact with the external world. The P300 potential is one of the most used control signals for EEG-based BCIs. Classic P300-based BCIs work in a synchronous mode; the synchronous control assumes that the user is constantly attending to the stimulation, and the number of stimulation sequences is fixed a priori. This issue is an obstacle for the use of these systems in everyday life; users will be engaged in a continuous control state, their distractions will cause misclassification and the speed of selection will not take into account users' current psychophysical condition. An efficient BCI system should be able to understand the user's intentions from the ongoing EEG instead. Also, it has to refrain from making a selection when the user is engaged in a different activity and it should increase or decrease its speed of selection depending on the current user's state. We addressed these issues by introducing an asynchronous BCI and tested its capabilities for effective environmental monitoring, involving 11 volunteers in three recording sessions. Results show that this BCI system can increase the bit rate during control periods while the system is proved to be very efficient in avoiding false negatives when the users are engaged in other tasks.

  3. 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.

  4. Asynchronous parallel generating set search for linearly-constrained optimization.

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, Tamara G.; Griffin, Joshua; Lewis, Robert Michael

    2007-04-01

    We describe an asynchronous parallel derivative-free algorithm for linearly-constrained optimization. Generating set search (GSS) is the basis of ourmethod. At each iteration, a GSS algorithm computes a set of search directionsand corresponding trial points and then evaluates the objective function valueat each trial point. Asynchronous versions of the algorithm have been developedin the unconstrained and bound-constrained cases which allow the iterations tocontinue (and new trial points to be generated and evaluated) as soon as anyother trial point completes. This enables better utilization of parallel resourcesand a reduction in overall runtime, especially for problems where the objec-tive function takes minutes or hours to compute. For linearly-constrained GSS,the convergence theory requires that the set of search directions conform to the3 nearby boundary. The complexity of developing the asynchronous algorithm forthe linearly-constrained case has to do with maintaining a suitable set of searchdirections as the search progresses and is the focus of this research. We describeour implementation in detail, including how to avoid function evaluations bycaching function values and using approximate look-ups. We test our imple-mentation on every CUTEr test problem with general linear constraints and upto 1000 variables. Without tuning to individual problems, our implementationwas able to solve 95% of the test problems with 10 or fewer variables, 75%of the problems with 11-100 variables, and nearly half of the problems with100-1000 variables. To the best of our knowledge, these are the best resultsthat have ever been achieved with a derivative-free method. Our asynchronousparallel implementation is freely available as part of the APPSPACK software.4

  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. Faculty development and mentorship using selected online asynchronous teaching strategies.

    Science.gov (United States)

    Vitale, Anne T

    2010-12-01

    The use of distance learning continues to improve accessibility to nursing education programs, yet online teaching remains an intimidating experience for novice educators. An emerging role in professional faculty development is the online educator, who serves as a mentor for novice faculty. This article presents the necessary elements to plan, organize, and manage asynchronous online courses, especially for novice educators and online faculty mentors. Course engagement and faculty-student online communication strategies are explored using examples. Threaded discussion strategies for engaging students in active, collaborative learning are discussed using specific examples. A threaded discussion grading rubric is included. Strategies to sustain interactive learning and evaluate student learning using examples are offered.

  7. 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.

  8. Positive semidefinite integrated covariance estimation, factorizations and asynchronicity

    DEFF Research Database (Denmark)

    Sauri, Orimar; Lunde, Asger; Laurent, Sébastien;

    2017-01-01

    An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization of the covariance matrix in order to exploit the heterogeneity in trading intensities to estimate the different parameters sequentially with as many...... observations as possible. The estimator is positive semidefinite by construction. We derive asymptotic results and confirm their good finite sample properties by means of a Monte Carlo simulation. In the application we forecast portfolio Value-at-Risk and sector risk exposures for a portfolio of 52 stocks. We...

  9. Negative circuits and sustained oscillations in asynchronous automata networks

    CERN Document Server

    Richard, Adrien

    2009-01-01

    The biologist Ren\\'e Thomas conjectured, twenty years ago, that the presence of a negative feedback circuit in the interaction graph of a dynamical system is a necessary condition for this system to produce sustained oscillations. In this paper, we state and prove this conjecture for asynchronous automata networks, a class of discrete dynamical systems extensively used to model the behaviors of gene networks. As a corollary, we obtain the following fixed point theorem: given a product $X$ of $n$ finite intervals of integers, and a map $F$ from $X$ to itself, if the interaction graph associated with $F$ has no negative circuit, then $F$ has at least one fixed point.

  10. A wavelet approach to binary blackholes with asynchronous multitasking

    Science.gov (United States)

    Lim, Hyun; Hirschmann, Eric; Neilsen, David; Anderson, Matthew; Debuhr, Jackson; Zhang, Bo

    2016-03-01

    Highly accurate simulations of binary black holes and neutron stars are needed to address a variety of interesting problems in relativistic astrophysics. We present a new method for the solving the Einstein equations (BSSN formulation) using iterated interpolating wavelets. Wavelet coefficients provide a direct measure of the local approximation error for the solution and place collocation points that naturally adapt to features of the solution. Further, they exhibit exponential convergence on unevenly spaced collection points. The parallel implementation of the wavelet simulation framework presented here deviates from conventional practice in combining multi-threading with a form of message-driven computation sometimes referred to as asynchronous multitasking.

  11. 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...

  12. 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.

  13. 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…

  14. 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...

  15. Exploring the Effect of Scripted Roles on Cognitive Presence in Asynchronous Online Discussions

    Science.gov (United States)

    Olesova, Larisa; Slavin, Margaret; Lim, Jieun

    2016-01-01

    The purpose of this study was to identify the effect of scripted roles on students' level of cognitive presence in asynchronous online threaded discussions. A quantitative content analysis was used to investigate: (1) what level of cognitive presence is achieved by students' assigned roles in asynchronous online discussions; (2) differences…

  16. 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

    The current state-of-the art in high-level synthesis of asynchronous circuits is syntax directed translation, which performs a one-to-one mapping of a HDL-description into a corresponding circuit. This paper presents a method for behavioral synthesis of asynchronous circuits which builds on top...... 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...

  17. An Asynchronous IEEE Floating-Point Arithmetic Unit

    Directory of Open Access Journals (Sweden)

    Joel R. Noche

    2007-12-01

    Full Text Available An asynchronous floating-point arithmetic unit is designed and tested at the transistor level usingCadence software. It uses CMOS (complementary metal oxide semiconductor and DCVS (differentialcascode voltage switch logic in a 0.35 µm process using a 3.3 V supply voltage, with dual-rail data andsingle-rail control signals using four-phase handshaking.Using 17,085 transistors, the unit handles single-precision (32-bit addition/subtraction, multiplication,division, and remainder using the IEEE 754-1985 Standard for Binary Floating-Point Arithmetic, withrounding and other operations to be handled by separate hardware or software. Division and remainderare done using a restoring subtractive algorithm; multiplication uses an additive algorithm. Exceptionsare noted by flags (and not trap handlers and the output is in single-precision.Previous work on asynchronous floating-point arithmetic units have mostly focused on single operationssuch as division. This is the first work to the authors' knowledge that can perform floating-point addition,multiplication, division, and remainder using a common datapath.

  18. Formation of the wide asynchronous binary asteroid population

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Seth A. [Department of Astrophysical and Planetary Science, UCB 391, University of Colorado, Boulder, CO 80309 (United States); Scheeres, Daniel J.; McMahon, Jay [Department of Aerospace Engineering Sciences, UCB 429, University of Colorado, Boulder, CO 80309 (United States)

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor 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, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of 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 torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  19. 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.

    2015-01-01

    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. PMID:27103749

  20. Designing Parallel Bus Using Universal Asynchronous Receiver Transmitter

    Directory of Open Access Journals (Sweden)

    Satyandra Sharad

    2013-04-01

    Full Text Available This paper entitled “DESIGNING PARALLEL BUSUSING UNIVERSAL ASYNCHRONOUS RECEIVER TRANSMITTER” is designed to the core of a UART interface module, which includes both receive and transmit modules, and the command parser. This paper will be a viable solution to design parallel buses with the help of UART. In the test bench , there is a RFM(register file model to which we write/read back data from just to check our design .The txt file issues serial inputs to the core and the core outputs parallel data and address in the form of bus. This bus is connected to our RFM (register file model instantiated in the test bench along with the design. This makes easy to retrieve parallel data from serial input. The base of the paper is to use microcontroller along with other components to interface with the physical world. In contrast, most serial communication must first be converted back into parallel form by a universal asynchronous receiver/transmitter (UART before they may be directly connected to a data bus. Both Transmissions (Parallel and Serial are used to connect peripheral devices and enable us to communicate with these devices. The UART core described here is designed using VHDL and implemented on Xilinx Vertex FPGA.

  1. Asynchronous glaciation at Nanga Parbat, northwestern Himalaya Mountains, Pakistan

    Science.gov (United States)

    Phillips, William M.; Sloan, Valerie F.; Shroder, John F., Jr.; Sharma, Pankaj; Clarke, Michèle L.; Rendell, Helen M.

    2000-05-01

    We present a new glacial chronology demonstrating asynchroneity between advances of Himalayan glaciers and Northern Hemisphere ice-sheet volumes. Glaciers at Nanga Parbat expanded during the early to middle Holocene ca. 9.0 5.5 ka. No major advances at Nanga Parbat during the last global glacial stage of marine oxygen isotope stage 2 (MIS-2) between 24 and 11 ka were identified. Preliminary evidence also indicates advances between ca. 60 and 30 ka. These periods of high ice volume coincide with warm, wet regional climates dominated by a strong southwest Asian summer monsoon. The general lack of deposits dating from MIS-2 suggests that Nanga Parbat was too arid to support expanded ice during this period of low monsoon intensity. Advances during warm, wet periods are possible for the high-altitude summer accumulation glaciers typical of the Himalayas, and explain asynchronous behavior. However, the Holocene advances at Nanga Parbat appear to have been forced by an abrupt drop in temperature ca. 8.4 8.0 ka and an increase in winter precipitation ca. 7 5.5 ka. These results highlight the overall sensitivity of Himalayan glaciation to orbital forcing of monsoon intensity, and on millennial or shorter time scales, to changes in North Atlantic circulation.

  2. Asynchronous Code-Division Random Access Using Convex Optimization

    CERN Document Server

    Applebaum, Lorne; Duarte, Marco F; Calderbank, Robert

    2011-01-01

    Many applications in cellular systems and sensor networks involve a random subset of a large number of users asynchronously reporting activity to a base station. This paper examines the problem of multiuser detection (MUD) in random access channels for such applications. Traditional orthogonal signaling ignores the random nature of user activity in this problem and limits the total number of users to be on the order of the number of signal space dimensions. Contention-based schemes, on the other hand, suffer from delays caused by colliding transmissions and the hidden node problem. In contrast, this paper presents a novel asynchronous (non-orthogonal) code-division random access scheme along with a convex optimization-based MUD algorithm that overcomes the issues associated with orthogonal signaling and contention-based methods. Two key distinguishing features of the proposed algorithm are that it does not require knowledge of the delay or channel state information of every user and it has polynomial-time com...

  3. Asynchronous Task-Based Polar Decomposition on Manycore Architectures

    KAUST Repository

    Sukkari, Dalal

    2016-10-25

    This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

  4. Asynchronously sampled blind source separation for coherent optical links

    Science.gov (United States)

    Detwiler, Thomas F.; Searcy, Steven M.; Stark, Andrew J.; Ralph, Stephen E.; Basch, Bert E.

    2011-01-01

    Polarization multiplexing is an integral technique for generating spectrally efficient 100 Gb/s and higher optical links. Post coherent detection DSP-based polarization demultiplexing of QPSK links is commonly performed after timing recovery. We propose and demonstrate a method of asynchronous blind source separation using the constant modulus algorithm (CMA) on the asynchronously sampled signal to initially separate energy from arbitrarily aligned polarization states. This method lends well to implementation as it allows for an open-loop sampling frequency for analog-to-digital conversion at less than twice the symbol rate. We show that the performance of subsequent receiver functions is enhanced by the initial pol demux operation. CMA singularity behavior is avoided through tap settling constraints. The method is applicable to QPSK transmissions and many other modulation formats as well, including general QAM signals, offset-QPSK, and CPM, or a combination thereof. We present the architecture and its performance under several different formats and link conditions. Comparisons of complexity and performance are drawn between the proposed architecture and conventional receivers.

  5. Continuous EEG signal analysis for asynchronous BCI application.

    Science.gov (United States)

    Hsu, Wei-Yen

    2011-08-01

    In this study, we propose a two-stage recognition system for continuous analysis of electroencephalogram (EEG) signals. An independent component analysis (ICA) and correlation coefficient are used to automatically eliminate the electrooculography (EOG) artifacts. Based on the continuous wavelet transform (CWT) and Student's two-sample t-statistics, active segment selection then detects the location of active segment in the time-frequency domain. Next, multiresolution fractal feature vectors (MFFVs) are extracted with the proposed modified fractal dimension from wavelet data. Finally, the support vector machine (SVM) is adopted for the robust classification of MFFVs. The EEG signals are continuously analyzed in 1-s segments, and every 0.5 second moves forward to simulate asynchronous BCI works in the two-stage recognition architecture. The segment is first recognized as lifted or not in the first stage, and then is classified as left or right finger lifting at stage two if the segment is recognized as lifting in the first stage. Several statistical analyses are used to evaluate the performance of the proposed system. The results indicate that it is a promising system in the applications of asynchronous BCI work.

  6. 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.

  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. DUSTY ENVIRONMENT IMPACT ON LIFESPAN OF THE INDUCTION MOTORS STATOR WINDING

    Directory of Open Access Journals (Sweden)

    V. E. Krivonosov

    2015-01-01

    Full Text Available Large quantity of asynchronous motors work in heavily dusted environments. On the end-winding insulation of the motors to 55 kW operating in the mining and smelting enterprise there is a 3 cm dust layer, which may lead to the asynchronous motor end-winding local overheat and consequent early breakdown. Contemporary literature allocates insufficient consideration to the issue of studying the impact the winding dust pollution has on the motor lifespan; for the most part they are experimental researches. The article investigates and establishes correlation relationship between the additional winding heating and the end-winding dust layer thickness. The investigation considers the induction motor winding to be a homogeneous solid and assumes the motor thermal conditions steady inasmuch as the winding insulation dust-cover forming time is much greater than the motor-heating time constant. The obtained expression permits determining the winding dust level by temperature variations; the dependence has linear character. Neither the motor type, size, nor the capacity do affect the local insulation overheating since the temperature difference between the windings being dust laden does not exceed 10 % for asynchronous motors of various capacity. The authors develop an appliance that enables the winding dustiness level monitoring and signals of necessity for the preventive cleaning measures implementation. The appliance operation principle is based on measuring results comparison of the two temperature-sensing devices mounted on the end-winding: one – in the upper part, and the other – in the bottom. The differential in the sensors reading-out allows estimating the dust layer sedimentation on the end-winding. A patent of invention has been issued on the investigation results. 

  9. Ultrasonic Motors

    Science.gov (United States)

    2003-06-01

    and T. Higuchi, "Cylindrical Micro Ultrasonic Motor Utilizing Bulk Lead Zirconate Titanate (PZT)," Japanese Journal of Applied Physics Part 1-Regular Papers Short Notes & Review Papers, vol. 38, pp. 3347-3350, 1999.

  10. Asynchronous API Pattern and its Application%异步接口模式及其应用

    Institute of Scientific and Technical Information of China (English)

    何华海; 丁柯

    2002-01-01

    In distributed systems,high efficiency can be achieved using asynchronous API between client and server.This paper provides an architectural pattern that implements asynchronous API generally. Asynchronous methods donot execute operations directly,however,they delegate the sending and receiving process to individual threads via aqueue ,the client deals with results by means of callback ,wait or check. Synchronous API is implemented on the baseof asynchronous API. Presently the asynchronous API pattern has been employed in the implementation of messagequeue middleware ISMQ.

  11. Asynchronous Multilateral Control for Simplified Walking Haptic System

    Science.gov (United States)

    Okura, Takeshi; Katsura, Seiichiro

    Recently, there has been extensive development in remote communication technologies such as telephone, radio, and television. Haptic information is studied as the third type of multimedia information. Real-world haptics is getting attention not only for the feedback of real-world haptic information in teleoperation but also as the key technology for future human support. Most of the objects of study in haptics are stationary. Therefore, the moving range of such haptic systems is limited. This paper proposes a novel haptic device that receives force feedback of walking motion from a remote environment and manipulates remote system. Thus, its moving range is unrestricted. To drive this haptic system, the paper also proposes asynchronous multilateral control. By using this control, an operator can operate the remote system without changing his/her position. The proposed haptic system is expected to act as an effective interface for virtual reality applications and teleoperation.

  12. Research on the displacement control method of asynchronous modular contactor

    Science.gov (United States)

    He, Gong; Ming, Zong

    2017-01-01

    Ac contactor is a kind of low voltage electrical appliances with large usage and wide application. Because of the frequent operation, contactor life must be long enough to ensure the reliable operation of power system. The electrical life of the contactor, as the key to affect the service life of the contactor, is mainly affected by the arc developed in the breaking and closing course. This paper concentrates on a new type of asynchronous modular contactor. To get the contactor movement characteristics, the dynamic model of the electromagnetic system is established by MATLAB/SIMULINK. Then, according to the displacement curve of contactor, the breaking process and closing process is planned. The thought of closed loop control, by adjusting the parameters of PID controller, enables the contactor to operate as the planning displacement curve. In addition, to achieve no arc or micro arc breaking and no bounce or micro bounce closing , a displacement closed loop control system for contactor is designed.

  13. 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.

  14. 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...

  15. Exploring Asynchronous Many-Task Runtime Systems toward Extreme Scales

    Energy Technology Data Exchange (ETDEWEB)

    Knight, Samuel [O8953; Baker, Gavin Matthew; Gamell, Marc [Rutgers U; Hollman, David [08953; Sjaardema, Gregor [SNL; Kolla, Hemanth [SNL; Teranishi, Keita; Wilke, Jeremiah J; Slattengren, Nicole [SNL; Bennett, Janine Camille

    2015-10-01

    Major exascale computing reports indicate a number of software challenges to meet the dramatic change of system architectures in near future. While several-orders-of-magnitude increase in parallelism is the most commonly cited of those, hurdles also include performance heterogeneity of compute nodes across the system, increased imbalance between computational capacity and I/O capabilities, frequent system interrupts, and complex hardware architectures. Asynchronous task-parallel programming models show a great promise in addressing these issues, but are not yet fully understood nor developed su ciently for computational science and engineering application codes. We address these knowledge gaps through quantitative and qualitative exploration of leading candidate solutions in the context of engineering applications at Sandia. In this poster, we evaluate MiniAero code ported to three leading candidate programming models (Charm++, Legion and UINTAH) to examine the feasibility of these models that permits insertion of new programming model elements into an existing code base.

  16. Indoor Positioning for Smartphones Using Asynchronous Ultrasound Trilateration

    Directory of Open Access Journals (Sweden)

    James D. Carswell

    2013-06-01

    Full Text Available 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 trilateration. We evaluate our indoor positioning approach by describing its strengths and weaknesses, and determine its absolute accuracy. This is accomplished through a range of experiments that involve variables such as position of control point microphones, position of phone within the room, direction speaker is facing and presence of user in the signal path. Test results show that our Lok8 (locate mobile positioning system can achieve accuracies better than 10 cm in a real-world environment.

  17. 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.

  18. H∞ Controller Design for Asynchronous Hybrid Systems with Multiple Delays

    Directory of Open Access Journals (Sweden)

    Xiaoqiang Sun

    2016-01-01

    Full Text Available Solutions for the H∞ synthesis problems of asynchronous hybrid systems with input-output delays are proposed. The continuous-time lifting approach of sampled-data systems is extended to a hybrid system with multiple delays, and some feasible formulas to calculate the operators of the equivalent discrete-time (DT system are given. Different from the existing methods derived from symplectic pair theory or by state augmentation, a Lyapunov-Krasovskii functional to solve the synthesis problem is explicitly constructed. The delay-dependent stability conditions we obtained can be described in terms of nonstrict linear matrix inequalities (LMIs, which are much more convenient to be solved by LMI tools.

  19. Estimation of delays in generalized asynchronous Boolean networks.

    Science.gov (United States)

    Das, Haimabati; Layek, Ritwik Kumar

    2016-10-20

    A new generalized asynchronous Boolean network (GABN) model has been proposed in this paper. This continuous-time discrete-state model captures the biological reality of cellular dynamics without compromising the computational efficiency of the Boolean framework. The GABN synthesis procedure is based on the prior knowledge of the logical structure of the regulatory network, and the experimental transcriptional parameters. The novelty of the proposed methodology lies in considering different delays associated with the activation and deactivation of a particular protein (especially the transcription factors). A few illustrative examples of some well-studied network motifs have been provided to explore the scope of using the GABN model for larger networks. The GABN model of the p53-signaling pathway in response to γ-irradiation has also been simulated in the current paper to provide an indirect validation of the proposed schema.

  20. Profiling individual discussants’ behaviours in online asynchronous discussions

    Directory of Open Access Journals (Sweden)

    Elizabeth Murphy

    2006-06-01

    Full Text Available This paper provides an illustrative example of an approach to creating and reporting individual profiles of engagement in particular behaviours in an online asynchronous discussion (OAD. Individual results of analysis of transcripts of an OAD can provide insights different from those gained by focusing on aggregate measures of group behaviours. In this case, we focused on individual behaviours associated with Problem Formulation and Resolution (PFR in a one-month long OAD with seven graduate students. The transcripts of each participant were analysed for patterns of PFR behaviours using a previously designed instrument. Individual profiles of the seven participants were created. The paper provides examples of how the approach facilitated identification and comparison of individual weaknesses and strengths. Also provided are examples of how individual profiles might be useful in professional development and instructional contexts for formative or summative assessment purposes.

  1. 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.

  2. Leader Election for Anonymous Asynchronous Agents in Arbitrary Networks

    CERN Document Server

    Dereniowski, Dariusz

    2012-01-01

    We study the problem of leader election among mobile agents operating in an arbitrary network modeled as an undirected graph. Nodes of the network are unlabeled and all agents are identical. Hence the only way to elect a leader among agents is by exploiting asymmetries in their initial positions in the graph. Agents do not know the graph or their positions in it, hence they must gain this knowledge by navigating in the graph and share it with other agents to accomplish leader election. This can be done using meetings of agents, which is difficult because of their asynchronous nature: an adversary has total control over the speed of agents. When can a leader be elected in this adversarial scenario and how to do it? We give a complete answer to this question by characterizing all initial configurations for which leader election is possible and by constructing an algorithm that accomplishes leader election for all configurations for which this can be done.

  3. 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.

  4. 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.

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

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia; Sparsø, Jens

    2014-01-01

    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...

  6. Towards behavioral synthesis of asynchronous circuits - an implementation template targeting syntax directed compilation

    DEFF Research Database (Denmark)

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

    2004-01-01

    This paper presents a method for behavioral synthesis of asynchronous circuits. Our approach aims at providing a synthesis flow which is very similar to what is found in existing synchronous design tools. We adapt the synchronous behavioral synthesis abstraction into the asynchronous handshake...... domain by introducing a computation model, which resembles the synchronous datapath and control architecture, but which is completely asynchronous. The datapath and control architecture is then expressed in the Balsa-language, and using syntax directed compilation a corresponding handshake circuit...... implementation is produced. The paper also reports area, speed and power figures for a couple of benchmark circuits, which have been synthesized to layout....

  7. 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.

  8. 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...

  9. Distributed Consensus of Stochastic Delayed Multi-agent Systems Under Asynchronous Switching.

    Science.gov (United States)

    Wu, Xiaotai; Tang, Yang; Cao, Jinde; Zhang, Wenbing

    2016-08-01

    In this paper, the distributed exponential consensus of stochastic delayed multi-agent systems with nonlinear dynamics is investigated under asynchronous switching. The asynchronous switching considered here is to account for the time of identifying the active modes of multi-agent systems. After receipt of confirmation of mode's switching, the matched controller can be applied, which means that the switching time of the matched controller in each node usually lags behind that of system switching. In order to handle the coexistence of switched signals and stochastic disturbances, a comparison principle of stochastic switched delayed systems is first proved. By means of this extended comparison principle, several easy to verified conditions for the existence of an asynchronously switched distributed controller are derived such that stochastic delayed multi-agent systems with asynchronous switching and nonlinear dynamics can achieve global exponential consensus. Two examples are given to illustrate the effectiveness of the proposed method.

  10. 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....

  11. 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.

  12. 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.

  13. 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.

  14. INVESTIGATION OF ASYNCHRONOUS OPTICAL COMMUNICATION CHANNEL THROUGHPUT CONTAINING A RECEIVER ON THE BASIS OF PHOTON COUNTER

    Directory of Open Access Journals (Sweden)

    I. R. Gulakov

    2013-01-01

    Full Text Available A mathematical model of asynchronous optical communication channel with a photon counter applied as a receiving module has been built. The expression for calculating of data throughput of this channel has been obtained. As a result of implemented experimental investigations it has been established that the data throughput of asynchronous optical communication channel containing a photon counter on the basis of avalanche photodetector as a receiving module depends on optical radiation and photodetector supply voltage.

  15. D-MG Tradeoff of DF and AF Relaying Protocols over Asynchronous PAM Cooperative Networks

    OpenAIRE

    Torbatian, Mehdi; Damen, Mohamed Oussama

    2009-01-01

    The diversity multiplexing tradeoff of a general two-hop asynchronous cooperative network is examined for various relaying protocols such as 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). The transmitter nodes are assumed to send pulse amplitude modulation (PAM) signals asynchronously, in which information symbols are linearly modulated by a shaping waveform...

  16. Universal asynchronous RSFQ gate for realization of Boolean functions of dual-rail binary variables

    Energy Technology Data Exchange (ETDEWEB)

    Dimov, B [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany); Khabipov, M [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Balashov, D [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Brandt, C M [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Ortlepp, Th [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany); Hagedorn, D [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Buchholz, F-Im [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Niemeyer, J [Physikalisch-Technische Bundesanstalt, Division 2.42, Bundesallee 100, D-38116 Braunschweig (Germany); Uhlmann, F H [University of Technology Ilmenau, Institute for Information Technology, PO Box 100565, D-98684 Ilmenau (Germany)

    2006-06-01

    We report on the design, optimization, fabrication, and successful testing of an universal asynchronous RSFQ logic gate based on the dual-rail data coding. Properly connecting its inputs and outputs, one can perform most of the basic Boolean functions over a pair of dual-rail input variables. Therefore, this gate is fundamental component for the development of high-speed complex asynchronous RSFQ digital devices.

  17. 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.

  18. 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...

  19. 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

  20. The double-temperature ratchet model and current reversal of coupled Brownian motors

    CERN Document Server

    Li, Chen-pu; Zheng, Zhi-gang

    2016-01-01

    Based on the transport features and experimental phenomena observed in studies of molecular motors, we proposed the double-temperature ratchet model of coupled motors to reveal the dynamical mechanism of cooperative transport of motors with two heads, where the interactions and the asynchronous between two motor heads are taken into account. We investigated the collective unidirectional transport of coupled system, and find that the direction of motion can be inversed under certain conditions. Inverse motion can be achieved by modulating the coupling strength, the coupling free length and the asymmetric efficient of the periodic potential, which is understood in terms of the effective-potential theory. The dependence of directed current on various parameters is studied systematically. Directed transport of coupled Brownian motors can be manipulated and optimized by adjusting pulsating period or the phase shift of the pulsating temperature.

  1. 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.

  2. 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.

  3. Photonic analog-to-digital converter via asynchronous oversampling

    Science.gov (United States)

    Carver, Spencer; Reeves, Erin; Siahmakoun, Azad; Granieri, Sergio

    2012-06-01

    This paper presents a hybrid opto-electronic asynchronous delta-sigma modulator, implemented in the form of a fiber-optic Analog-to-Digital converter (ADC). This architecture was chosen for its independence of an external clock and ease of demodulation through a single low-pass filter stage. The fiber-optic prototype consists of an input laser (wavelength λ1) which is modulated with an input RF signal, a high-speed comparator circuit working as bi-stable quantizer, and a fiber-optic loop that includes a SOA and a band-pass filter that act as a leaky integrator. The fiber-optic loop acts as a fiber-ring resonator (FRR), and defines the resonance wavelength λ2 of the system. The gain within this loop is modified through cross-gain modulation (XGM) by the input wavelength λ1, and thus achieves the desired modulation effect. The proposed architecture has been constructed and characterized at a sampling rate of 15.4 MS/s processing input analog signals in the range of dc-3 MHz with a signal-to-noise ratio of 36 dB and an effective number of bits of 5.7.

  4. ACK filling void first algorithm and performance for asynchronous OPS

    Science.gov (United States)

    Liu, Huanlin; Shi, Yonghe; Chen, Qianbin; Pan, Yingjun

    2007-11-01

    OPS with feedback shared FDL buffer produce large voids due to FDL buffers only supplying discrete step delay and causing FDL queue virtually occupation. By analyzing the TCP traffic and ACK packets feature, the ACK packet void filling first scheduling is presented to decrease packet loss rate and to reduce the FDL voids. When the FDL buffer void size is fit for the ACK packet, the ACK packet is scheduled to FDL immediately. An ACK and non-ACK packets difference and process flow is designed according the TCP packet frame structure. Compared with the conventional FIFO scheduling and smallest FDL void first scheduling, the algorithm reduces greatly the number of ACK occupying the FDL buffer and eliminates large numbers of ACK's bad influence on efficiency of IP data transmission under different FDL buffer depth and traffic load. The results of simulation show that the proposed scheduling makes use of ACK packets first void filling scheduling mechanism to reduce FDL excess load, increases output utilization and reduce packet loss ratio for asynchronous optical network. This approach is shown to minimize the FDL numbers with the feature of high stabilization and photonic integration and to improve real time TCP traffic performance for Internet network.

  5. Normalized and asynchronous mirror alignment for Cherenkov telescopes

    Science.gov (United States)

    Ahnen, M. L.; Baack, D.; 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.

    2016-09-01

    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 can reconstruct all individual mirror facet point spread functions without moving any mirror. We present alignment results on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

  6. Asynchronous Dual-Rail Transition Logic for Enhanced DPA Resistance

    Directory of Open Access Journals (Sweden)

    Rajath Srivathsav N

    2015-02-01

    Full Text Available An Asynchronous Dual–Rail Transition Logic (ADTL is proposed in this paper. The new logic style can be used in the encryption circuit of cryptography to counter the differential power analysis (DPA attacks. The resistance to the DPA attacks is achieved by randomizing the power dissipated in the circuit through Manchester input signal coding and unpredictable initial state of the toggle flip-flops (TFF. The proposed logic uses two wires to transmit the signal, in the form of a single transition on either one of the two wires to indicate the input logic value. T-FFs are employed to randomize the power dissipated by the circuit. The randomizing is made possible by making the initial states of the flip-flops un-deterministic. Furthermore, the clock is completely eliminated in the conceived design, thus realizing increased power randomization and resistance to the DPA attacks. The design is demonstrated through the systematic simulations on a typical encryption circuit. The validation of the ADTL is made through extensive comparisons with the existing Dual-rail Transition Logic (DTL for power, delay and the DPA resistance. Industry standard EDA tools with 90nm technology libraries provided by the UMC foundry have been employed in the designs.

  7. Maximum likelihood reconstruction for Ising models with asynchronous updates

    CERN Document Server

    Zeng, Hong-Li; Aurell, Erik; Hertz, John; Roudi, Yasser

    2012-01-01

    We describe how the couplings in a non-equilibrium Ising model can be inferred from observing the model history. Two cases of an asynchronous update scheme are considered: one in which we know both the spin history and the update times (times at which an attempt was made to flip a spin) and one in which we only know the spin history (i.e., the times at which spins were actually flipped). In both cases, maximizing the likelihood of the data leads to exact learning rules for the couplings in the model. For the first case, we show that one can average over all possible choices of update times to obtain a learning rule that depends only on spin correlations and not on the specific spin history. For the second case, the same rule can be derived within a further decoupling approximation. We study all methods numerically for fully asymmetric Sherrington-Kirkpatrick models, varying the data length, system size, temperature, and external field. Good convergence is observed in accordance with the theoretical expectatio...

  8. Network inference using asynchronously updated kinetic Ising Model

    CERN Document Server

    Zeng, Hong-Li; Alava, Mikko; Mahmoudi, Hamed

    2010-01-01

    Network structures are reconstructed from dynamical data by respectively naive mean field (nMF) and Thouless-Anderson-Palmer (TAP) approximations. For TAP approximation, we use two methods to reconstruct the network: a) iteration method; b) casting the inference formula to a set of cubic equations and solving it directly. We investigate inference of the asymmetric Sherrington- Kirkpatrick (S-K) model using asynchronous update. The solutions of the sets cubic equation depend of temperature T in the S-K model, and a critical temperature Tc is found around 2.1. For T Tc there are three real roots. The iteration method is convergent only if the cubic equations have three real solutions. The two methods give same results when the iteration method is convergent. Compared to nMF, TAP is somewhat better at low temperatures, but approaches the same performance as temperature increase. Both methods behave better for longer data length, but for improvement arises, TAP is well pronounced.

  9. MATHEMATICAL MODELING OF AC ELECTRIC POINT MOTOR

    Directory of Open Access Journals (Sweden)

    S. YU. Buryak

    2014-03-01

    Full Text Available Purpose. In order to ensure reliability, security, and the most important the continuity of the transportation process, it is necessary to develop, implement, and then improve the automated methods of diagnostic mechanisms, devices and rail transport systems. Only systems that operate in real time mode and transmit data on the instantaneous state of the control objects can timely detect any faults and thus provide additional time for their correction by railway employees. Turnouts are one of the most important and responsible components, and therefore require the development and implementation of such diagnostics system.Methodology. Achieving the goal of monitoring and control of railway automation objects in real time is possible only with the use of an automated process of the objects state diagnosing. For this we need to know the diagnostic features of a control object, which determine its state at any given time. The most rational way of remote diagnostics is the shape and current spectrum analysis that flows in the power circuits of railway automatics. Turnouts include electric motors, which are powered by electric circuits, and the shape of the current curve depends on both the condition of the electric motor, and the conditions of the turnout maintenance. Findings. For the research and analysis of AC electric point motor it was developed its mathematical model. The calculation of parameters and interdependencies between the main factors affecting the operation of the asynchronous machine was conducted. The results of the model operation in the form of time dependences of the waveform curves of current on the load on engine shaft were obtained. Originality. During simulation the model of AC electric point motor, which satisfies the conditions of adequacy was built. Practical value. On the basis of the constructed model we can study the AC motor in various mode of operation, record and analyze current curve, as a response to various changes

  10. 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

  11. Asynchronous vascular consultation via electronic methods: A feasibility pilot.

    Science.gov (United States)

    Chittle, Melissa D; Rao, Sandhya K; Jaff, Michael R; Patel, Virendra I; Gallen, Kathleen M; Avadhani, Radhika; Ferris, Timothy G; Wasfy, Jason H

    2015-12-01

    Management of chronic disease often requires multidisciplinary clinical efforts and specialist care. With the emergence of Accountable Care Organizations (ACOs), health care systems are incentivized to evaluate methods of information exchange between generalists and specialists in order to provide value while preserving quality. Our objective was to evaluate patient and referring provider satisfaction and outcomes of asynchronous electronic consultations in vascular care in a large tertiary academic medical center. Referring providers were offered a vascular 'e-consult' option through an electronic referral management system. We conducted chart review to understand the downstream effects and surveyed patients and referring providers to assess satisfaction. From 24 March 2014 to 1 March 2015, 54 e-consults were completed. Additional testing and recommendations were made in 49/54 (90.7%) e-consults, including lower-extremity venous duplex ultrasonography with reflux testing, duplex ultrasonography of the carotid artery, computed tomography, magnetic resonance imaging, non-invasive physiology arterial studies, laboratory tests, medications, compression stockings, and sequential lymphedema compression therapy. Referring providers were compliant with recommendations in 40/49 (81.6%) of e-consults. A total of 17/54 (31.5%) patients were surveyed with a median patient satisfaction score of 13.7/15 (91.3%) (SD ± 6.4). The program was associated with high referring provider satisfaction, with 87.0% finding the e-consult very helpful and 80.0% stating it averted the need for a traditional visit. Our experience suggests that e-consults are an effective way to provide vascular care in some patients and are associated with high patient and provider satisfaction. E-consults may therefore be an efficient method of care delivery for vascular patients within an ACO.

  12. 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.

  13. 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.

  14. 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.

  15. Commande directe du couple d'une machine asynchrone par le contrôle direct de son flux statorique

    Science.gov (United States)

    Chapuis, Y. A.; Roye, D.; Courtine, S.

    1995-06-01

    The authors of this paper present a vector control scheme of an induction motor, in order to reduce parameter sensibility problems expected in most rotor flux oriented. Direct torque control principles have been introduced, moreover a simulation module and an experimental device have been proposed to estimate the possibilities of the proposal. Futhermore, they describe the methods they use to obtain good performances, even in the low speed range, where the stator resistance influence becomes critical. Les auteurs de cet article présentent une structure de contrôle vectorielle de la machine asynchrone, proposant une alternative à la commande à flux rotorique orientée en réduisant l'influence des paramètres propres à cette méthode. Les principes du contrôle direct du couple sont introduit, de plus un module de simulation et un dispositif expérimental sont proposés, permettant d'évaluer les possibilités de la structure. Finalement, les auteurs illustrent le bon fonctionnement du système, par une étude du comportement aux basses vitesses, où l'influence de la résistance statorique peut être critique.

  16. 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.

  17. Methodological Reflections on the Use of Asynchronous Online Focus Groups in Health Research

    Directory of Open Access Journals (Sweden)

    Sarah Williams PhD

    2012-09-01

    Full Text Available The Internet is increasingly used as a tool in qualitative research. In particular, asynchronous online focus groups are used when factors such as cost, time, or access to participants can make conducting face-to-face research difficult. In this article we consider key methodological issues involved in using asynchronous online focus groups to explore experiences of health and illness. The written nature of Internet communication, the lack of physical presence, and the asynchronous, longitudinal aspects enable participants who might not normally contribute to research studies to reflect on their personal stories before disclosing them to the researcher. Implications for study design, recruitment strategies, and ethics should be considered when deciding whether to use this method.

  18. Développement de lois de commandes avec observateurs pour machine asynchrone

    OpenAIRE

    Alvarez Salas, Ricardo

    2002-01-01

    Ce travail s'inscrit dans le cadre général de l'observation et de la commande non linéaire de machine asynchrone. Ce mémoire comporte cinq volets. La première partie donne les éléments de modélisation de la machine asynchrone ainsi que sa représentation dans différentes repères de coordonnées. La deuxième partie est dédiée aux observateurs de flux et de couple de charge pour machine asynchrone en vue de bonnes performances dans toute la gamme de vitesse. Nous présentons deux méthodes de synth...

  19. 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.

  20. Simulating the operation action of an asynchronized turbogenerator under loss of excitation

    Institute of Scientific and Technical Information of China (English)

    SANGARE Adama Fanhiri; YANG Shunchang; LIU Ren

    2004-01-01

    The control strategy tor asynchronized turbogenerators (ASTGs) was studied by using two-axis equations. Simulation of the process of an asynchronized turbogenerator with faults of d or q axis or d and q axes in the excitation system was carried out with the simulating models including the model of the reverse thyristors in the excitation system established by Saber software. The simulation results show that at the loss of excitation at both windings or one winding of the rotor, the ASTGs can be automatically driven into an asynchronous or single axis excitation operation mode without a power unit tripping, and the characteristics for ASTGs with faults in the excitation system appear in good order.

  1. 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...... 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. All...

  2. Universal regular autonomous asynchronous systems: omega-limit sets, invariance and basins of attraction

    CERN Document Server

    Vlad, Serban E

    2010-01-01

    The asynchronous systems are the non-deterministic real time-binary models 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 the real time dynamical systems with a 'vector field' {\\Phi}:{0,1}^2 \\rightarrow {0,1}^2. Universality refers to the case when the state space of the system is the greatest possible in the sense of the inclusion. The purpose of the 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.

  3. 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.

  4. Gigabit Ethernet signal transmission using asynchronous optical code division multiple access.

    Science.gov (United States)

    Ma, Philip Y; Fok, Mable P; Shastri, Bhavin J; Wu, Ben; Prucnal, Paul R

    2015-12-15

    We propose and experimentally demonstrate a novel architecture for interfacing and transmitting a Gigabit Ethernet (GbE) signal using asynchronous incoherent optical code division multiple access (OCDMA). This is the first such asynchronous incoherent OCDMA system carrying GbE data being demonstrated to be working among multi-users where each user is operating with an independent clock/data rate and is granted random access to the network. Three major components, the GbE interface, the OCDMA transmitter, and the OCDMA receiver are discussed in detail. The performance of the system is studied and characterized through measuring eye diagrams, bit-error rate and packet loss rate in real-time file transfer. Our Letter also addresses the near-far problem and realizes asynchronous transmission and detection of signal.

  5. GPU-Accelerated Asynchronous Error Correction for Mixed Precision Iterative Refinement

    Energy Technology Data Exchange (ETDEWEB)

    Antz, Hartwig [Karlsruhe Inst. of Technology (KIT) (Germany); Luszczek, Piotr [Univ. of Tennessee, Knoxville, TN (United States); Dongarra, Jack [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Manchester (United Kingdom); Heuveline, Vinent [Karlsruhe Inst. of Technology (KIT) (Germany)

    2011-12-14

    In hardware-aware high performance computing, block- asynchronous iteration and mixed precision iterative refinement are two techniques that are applied to leverage the computing power of SIMD accelerators like GPUs. Although they use a very different approach for this purpose, they share the basic idea of compensating the convergence behaviour of an inferior numerical algorithm by a more efficient usage of the provided computing power. In this paper, we want to analyze the potential of combining both techniques. Therefore, we implement a mixed precision iterative refinement algorithm using a block-asynchronous iteration as an error correction solver, and compare its performance with a pure implementation of a block-asynchronous iteration and an iterative refinement method using double precision for the error correction solver. For matrices from theUniversity of FloridaMatrix collection,we report the convergence behaviour and provide the total solver runtime using different GPU architectures.

  6. 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 ...

  7. An Achievable Rate Region for the Asynchronous Multiple Access Channel with Feedback

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An achievable rate region for the asynchronous multiple access channel with feedback is established through the use of superposition coding, list decoding and time sharing. The calculation results demonstrate that lack of synchronization does not affect the achievable rate region when the code block length tends to infinity, and that if the length of the code word is finite, especially not sufficiently larger than a fixed maximal delay, the asynchronization will cause a loss of the rate region. The amount of such a loss with its explanation for the reason is given, and the difference between the losses for the asynchronous multiple access channel with and without feedback is also discussed in this paper.

  8. Electric motors. An introduction. 3. ed.; Elektrische Maschinen. Eine Einfuehrung

    Energy Technology Data Exchange (ETDEWEB)

    Spring, Eckhard [Fachhochschule Giessen Friedberg, Univ. of Applied Sciences (Germany). Fachgebiet Elektrische Energietechnik / Electric Energy Systems

    2009-07-01

    Written for the practitioner and practice-oriented study this textbook of 3rd edition covers the DC motor, the transformer and the asynchronous and the synchronous machine, with an emphasis on operating behaviour. The material is presented in a manner that awakens an understanding of physical processes while avoiding mathematical formalisms. It contains numerous examples and exercises that allow students to familiarise themselves with the study material and give them a feeling for orders of magnitude. Having worked through the book students will be in a position to investigate the operating behaviour of electrical motors by experiment and calculation. (GL) [German] Dieses Lehrbuch fuer die Praxis und das praxisorientierte Studium liegt nun in der 3. Auflage vor. Es behandelt die Gleichstrommaschine, den Transformator, die Asynchron- und die Synchronmaschine. Das Betriebsverhalten steht im Vordergrund. Durch die anschauliche Art der Darstellung weckt der Autor das Verstaendnis fuer die physikalischen Vorgaenge und vermeidet mathematische Formalismen. Zahlreiche Beispiele und Aufgaben dienen zum Einueben des Lehrstoffes und vermitteln ein Gefuehl fuer sinnvolle Groessenordnungen. Nach dem Durcharbeiten des Buches ist der Leser in der Lage, das Betriebsverhalten der behandelten Maschinen experimentell und rechnerisch zu untersuchen. (orig.)

  9. Exploration of a Few Different AC Motor Autorotation%几种不同交流电机“自转”的探究

    Institute of Scientific and Technical Information of China (English)

    秦常贵

    2011-01-01

    Applying magnetic field theory and higher mathematics and human-computer interaction software, the reasons why three-phase asynchronous motor and single-phase asynchronous motor can "autorotate" in the pulsating magnetic field, but AC servo motor, operating principle of which is similar to that of single-phase asynchronous motor, cannot be studied in detail. Besides, the author put forward the statement "elimination of AC servo motor autorotation " is defective.%应用磁场理论、高等数学和人机交互软件,对三相异步电动机和单相异步电动机为什么会产生“自转”,而与单相异步电动机工作原理非常相似的二相交流伺服电动机却为什么不会产生“自转”的原因进行了详尽的研究.

  10. The Effects of Metacognitive Instruction Embedded within an Asynchronous Learning Network on Scientific Inquiry Skills. Research Report

    Science.gov (United States)

    Zion, Michal; Michalsky, Tova; Mevarech, Zemira R.

    2005-01-01

    The study is aimed at investigating the effects of four learning methods on students' scientific inquiry skills. The four learning methods are: (a) metacognitive-guided inquiry within asynchronous learning networked technology (MINT); (b) an asynchronous learning network (ALN) with no metacognitive guidance; (c) metacognitive-guided inquiry…

  11. Differences in Electronic Exchanges in Synchronous and Asynchronous Computer-Mediated Communication: The Effect of Culture as a Mediating Variable

    Science.gov (United States)

    Angeli, Charoula; Schwartz, Neil H.

    2016-01-01

    Two hundred and eighty undergraduates from universities in two countries were asked to read didactic material, and then think and write about potential solutions to an ill-defined problem. The writing was conducted within a synchronous or asynchronous computer-mediated communication (CMC) environment. Asynchronous CMC took the form of email…

  12. An Examination of the Effectiveness of Embedded Audio Feedback for English as a Foreign Language Students in Asynchronous Online Discussions

    Science.gov (United States)

    Olesova, Larisa A.

    2011-01-01

    This study examined the effect of asynchronous embedded audio feedback on English as a Foreign Language (EFL) students' higher-order learning and perception of the audio feedback versus text-based feedback when the students participated in asynchronous online discussions. In addition, this study examined how the impact and perceptions differed…

  13. 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

  14. 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 leg). ... Gross motor control is a milestone in the development of an infant. Infants develop gross motor control before they develop ...

  15. 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.

  16. 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...... 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...

  17. 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. ...... the implications it has on the choice of architecture, handshake-protocol, data-encoding, and circuit design. This includes a tagging scheme that divides the data-path into slices, and an asynchronous ripple carry adder that avoids a completion tree....

  18. Asynchronous teaching of psychomotor skills through VR annotations: evaluation in digital rectal examination.

    Science.gov (United States)

    Rissanen, Mikko J; Kume, Naoto; Kuroda, Yoshihiro; Kuroda, Tomohiro; Yoshimura, Koji; Yoshihara, Hiroyuki

    2008-01-01

    Many VR technology based training systems use expert's motion data as the training aid, but would not provide any short-cut to teaching medical skills that do not depend on exact motions. Earlier we presented Annotated Simulation Records (ASRs), which can be used to encapsulate experts' insight on psychomotor skills. Annotations made to behavioural parameters in training simulators enable asynchronous teaching instead of just motion training in a proactive way to the learner. We evaluated ASRs for asynchronous teaching of Digital Rectal Examination (DRE) with 3 urologists and 8 medical students. The ASRs were found more effective than motion-based training with verbal feedback.

  19. Finite-time quantised feedback asynchronously switched control of sampled-data switched linear systems

    Science.gov (United States)

    Wang, Ronghao; Xing, Jianchun; Li, Juelong; Xiang, Zhengrong

    2016-10-01

    This paper studies the problem of stabilising a sampled-data switched linear system by quantised feedback asynchronously switched controllers. The idea of a quantised feedback asynchronously switched control strategy originates in earlier work reflecting actual system characteristic of switching and quantising, respectively. A quantised scheme is designed depending on switching time using dynamic quantiser. When sampling time, system switching time and controller switching time are all not uniform, the proposed switching controllers guarantee the system to be finite-time stable by a piecewise Lyapunov function and the average dwell-time method. Simulation examples are provided to show the effectiveness of the developed results.

  20. 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.

  1. 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.

  2. 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...

  3. 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…

  4. 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…

  5. Pedagogical dimensions of effective online asynchronous teacher communication in higher education

    NARCIS (Netherlands)

    Smits, A.; Voogt, J.; Rutledge, D.; Slykhuis, D.

    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

  6. 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.

  7. 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…

  8. 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 and…

  9. 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 [subscript…

  10. Participation in Asynchronous Online Discussion Forums Does Improve Student Learning of Gross Anatomy

    Science.gov (United States)

    Green, Rodney A.; Farchione, Davide; Hughes, Diane L.; Chan, Siew-Pang

    2014-01-01

    Asynchronous online discussion forums are common in blended learning models and are popular with students. A previous report has suggested that participation in these forums may assist student learning in a gross anatomy subject but it was unclear as to whether more academically able students post more often or whether participation led to…

  11. Using Asynchronous Electronic Surveys to Help In-Class Revision: A Case Study

    Science.gov (United States)

    Tong, Vincent C. H.

    2012-01-01

    Synchronous e-voting systems (commonly known as "clickers") have become increasingly popular as they can be used to enhance interactivity in lectures. Asynchronous electronic surveys (AESs), unlike these voting system, usually serve as a method of gathering feedback before or after teaching sessions. This paper describes and evaluates a project…

  12. 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.

  13. 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.

  14. 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

  15. Constructivist Pedagogy in Asynchronous Online Education: Examining Proactive Behavior and the Impact on Student Engagement Levels

    Science.gov (United States)

    Peters, Linda; Shmerling, Shirley; Karren, Ronald

    2011-01-01

    Asynchronous learning environments have gained popularity over the past decade and have rapidly gained acceptance in both the academic and business worlds. This study investigates the impact that student characteristics of proactive behavior and learning style preference have on student engagement levels when a collaborative learning process such…

  16. Computer Learner Corpora: Analysing Interlanguage Errors in Synchronous and Asynchronous Communication

    Science.gov (United States)

    MacDonald, Penny; Garcia-Carbonell, Amparo; Carot, Sierra, Jose Miguel

    2013-01-01

    This study focuses on the computer-aided analysis of interlanguage errors made by the participants in the telematic simulation IDEELS (Intercultural Dynamics in European Education through on-Line Simulation). The synchronous and asynchronous communication analysed was part of the MiLC Corpus, a multilingual learner corpus of texts written by…

  17. Ecological Affordance and Anxiety in an Oral Asynchronous Computer-Mediated Environment

    Science.gov (United States)

    McNeil, Levi

    2014-01-01

    Previous research suggests that the affordances (van Lier, 2000) of asynchronous computer-mediated communication (ACMC) environments help reduce foreign language anxiety (FLA). However, FLA is rarely the focus of these studies and research has not adequately addressed the relationship between FLA and the affordances that students use. This study…

  18. An Investigation of Assessment and Feedback Practices in Fully Asynchronous Online Undergraduate Mathematics Courses

    Science.gov (United States)

    Trenholm, Sven; Alcock, Lara; Robinson, Carol

    2015-01-01

    Research suggests it is difficult to learn mathematics in the fully asynchronous online (FAO) instructional modality, yet little is known about associated teaching and assessment practices. In this study, we investigate FAO mathematics assessment and feedback practices in particular consideration of both claims and findings that these practices…

  19. 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.

  20. 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.

  1. 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…

  2. Temperature, paternity and asynchronous hatching influence early developmental characteristics of larval Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Politis, Sebastian Nikitas; Dahlke, Flemming T.; Butts, Ian A.E.;

    2014-01-01

    Offspring, especially during early development, are influenced by both intrinsic properties endowed to them by their parents, extrinsic environmental factors as well as the interplay between genes and the environment. We investigated the effects of paternity (P), temperature (T), and asynchronous...

  3. Introducing group-based asynchronous learning to business education : Reflections on effective course design and delivery

    NARCIS (Netherlands)

    Arnold, I.J.M.; Walker, R.

    2004-01-01

    This paper explores the contribution of virtual tools to student learning within full-time management programmes. More specifically, the paper focuses on asynchronous communication tools, considering the scope they offer for group-based collaborative learning outside the classroom. We report on the

  4. 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…

  5. 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…

  6. 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…

  7. Selected Issues in Persistent Asynchronous Adaptive Specialization for Generic Functional Array Programming

    NARCIS (Netherlands)

    C. Grelck; H. Wiesinger

    2014-01-01

    Asynchronous adaptive specialization of rank- and shape-generic code for processing immutable (purely functional) multi-dimensional arrays has proven to be an effective technique to reconcile the desire for abstract specifications with the need to achieve reasonably high performance in sequential as

  8. An efficient algorithm for computing attractors of synchronous and asynchronous Boolean networks.

    Directory of Open Access Journals (Sweden)

    Desheng Zheng

    Full Text Available Biological networks, such as genetic regulatory networks, often contain positive and negative feedback loops that settle down to dynamically stable patterns. Identifying these patterns, the so-called attractors, can provide important insights for biologists to understand the molecular mechanisms underlying many coordinated cellular processes such as cellular division, differentiation, and homeostasis. Both synchronous and asynchronous Boolean networks have been used to simulate genetic regulatory networks and identify their attractors. The common methods of computing attractors are that start with a randomly selected initial state and finish with exhaustive search of the state space of a network. However, the time complexity of these methods grows exponentially with respect to the number and length of attractors. Here, we build two algorithms to achieve the computation of attractors in synchronous and asynchronous Boolean networks. For the synchronous scenario, combing with iterative methods and reduced order binary decision diagrams (ROBDD, we propose an improved algorithm to compute attractors. For another algorithm, the attractors of synchronous Boolean networks are utilized in asynchronous Boolean translation functions to derive attractors of asynchronous scenario. The proposed algorithms are implemented in a procedure called geneFAtt. Compared to existing tools such as genYsis, geneFAtt is significantly [Formula: see text] faster in computing attractors for empirical experimental systems.The software package is available at https://sites.google.com/site/desheng619/download.

  9. An Efficient Algorithm for Computing Attractors of Synchronous And Asynchronous Boolean Networks

    Science.gov (United States)

    Zheng, Desheng; Yang, Guowu; Li, Xiaoyu; Wang, Zhicai; Liu, Feng; He, Lei

    2013-01-01

    Biological networks, such as genetic regulatory networks, often contain positive and negative feedback loops that settle down to dynamically stable patterns. Identifying these patterns, the so-called attractors, can provide important insights for biologists to understand the molecular mechanisms underlying many coordinated cellular processes such as cellular division, differentiation, and homeostasis. Both synchronous and asynchronous Boolean networks have been used to simulate genetic regulatory networks and identify their attractors. The common methods of computing attractors are that start with a randomly selected initial state and finish with exhaustive search of the state space of a network. However, the time complexity of these methods grows exponentially with respect to the number and length of attractors. Here, we build two algorithms to achieve the computation of attractors in synchronous and asynchronous Boolean networks. For the synchronous scenario, combing with iterative methods and reduced order binary decision diagrams (ROBDD), we propose an improved algorithm to compute attractors. For another algorithm, the attractors of synchronous Boolean networks are utilized in asynchronous Boolean translation functions to derive attractors of asynchronous scenario. The proposed algorithms are implemented in a procedure called geneFAtt. Compared to existing tools such as genYsis, geneFAtt is significantly faster in computing attractors for empirical experimental systems. Availability The software package is available at https://sites.google.com/site/desheng619/download. PMID:23585840

  10. 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…

  11. 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…

  12. From Discrete-Time Models to Continuous-Time, Asynchronous Models of Financial Markets

    NARCIS (Netherlands)

    K. Boer-Sorban (Katalin); U. Kaymak (Uzay); J. Spiering (Jaap)

    2006-01-01

    textabstractMost agent-based simulation models of financial markets are discrete-time in nature. In this paper, we investigate to what degree such models are extensible to continuous-time, asynchronous modelling of financial markets. We study the behaviour of a learning market maker in a market with

  13. Embedded Vehicle Speed Estimation System Using an Asynchronous Temporal Contrast Vision Sensor

    Directory of Open Access Journals (Sweden)

    D. Bauer

    2007-01-01

    Full Text Available This article presents an embedded multilane traffic data acquisition system based on an asynchronous temporal contrast vision sensor, and algorithms for vehicle speed estimation developed to make efficient use of the asynchronous high-precision timing information delivered by this sensor. The vision sensor features high temporal resolution with a latency of less than 100 μs, wide dynamic range of 120 dB of illumination, and zero-redundancy, asynchronous data output. For data collection, processing and interfacing, a low-cost digital signal processor is used. The speed of the detected vehicles is calculated from the vision sensor's asynchronous temporal contrast event data. We present three different algorithms for velocity estimation and evaluate their accuracy by means of calibrated reference measurements. The error of the speed estimation of all algorithms is near zero mean and has a standard deviation better than 3% for both traffic flow directions. The results and the accuracy limitations as well as the combined use of the algorithms in the system are discussed.

  14. Theoretically Based Pedagogical Strategies Leading to Deep Learning in Asynchronous Online Gerontology Courses

    Science.gov (United States)

    Majeski, Robin; Stover, Merrily

    2007-01-01

    Online learning has enjoyed increasing popularity in gerontology. This paper presents instructional strategies grounded in Fink's (2003) theory of significant learning designed for the completely asynchronous online gerontology classroom. It links these components with the development of mastery learning goals and provides specific guidelines for…

  15. The Development of a Content Analysis Model for Assessing Students' Cognitive Learning in Asynchronous Online Discussions

    Science.gov (United States)

    Yang, Dazhi; Richardson, Jennifer C.; French, Brian F.; Lehman, James D.

    2011-01-01

    The purpose of this study was to develop and validate a content analysis model for assessing students' cognitive learning in asynchronous online discussions. It adopted a fully mixed methods design, in which qualitative and quantitative methods were employed sequentially for data analysis and interpretation. Specifically, the design was a…

  16. Trajectory exploration within asynchronous binary asteroid systems using refined Lagrangian coherent structures

    Science.gov (United States)

    Shang, Haibin; Wu, Xiaoyu; Cui, Pingyuan

    2017-02-01

    Ground observations have found that asynchronous systems constitute most of the population of the near-Earth binary asteroids. This paper concerns the trajectory of a particle in the asynchronous system which is systematically described using periodic ellipsoidal and spherical body models. Due to the non-autonomous characteristics of the asynchronous system, Lagrangian coherent structures (LCS) are employed to identify the various dynamical behaviors. To enhance the accuracy of LCS, a robust LCS finding algorithm is developed incorporating hierarchical grid refinement, one-dimensional search and variational theory verification. In this way, the intricate dynamical transport boundaries are detected efficiently. These boundaries indicate that a total of 15 types of trajectories exist near asynchronous binary asteroids. According to their Kepler energy variations, these trajectories can be grouped into four basic categories, i.e., transitory, escape, impact and flyby trajectories. Furthermore, the influence of the ellipsoid's spin period on the dynamical behavior is discussed in the context of the change of dynamical regions. We found that the transitory and impact motions occur easily in the synchronous-like binary systems, in which the rotation period of the ellipsoid is nearly equal to that of the mutual orbit. Meanwhile, the results confirm a positive correlation between the spinning rate of the ellipsoid and the probability of the escape and flyby trajectories. The LCS also reveal a marked increase in trajectory diversity after a larger initial energy is selected.

  17. Evaluation of a Computer-Based, Asynchronous Activity on Student Learning of Leadership Concepts.

    Science.gov (United States)

    Boyd, Barry L.; Murphrey, Theresa Pesl

    2002-01-01

    Students taught leadership and ethics using asynchronous computer simulation (n=83) were compared with 113 taught conventionally. The treatment group performed better on questions written at the knowledge, comprehension, and analysis levels of Bloom's Taxonomy, regardless of learning mode preferences. (Contains 26 references.) (SK)

  18. Learning about the Literacy Development of English Language Learners in Asynchronous Online Discussions

    Science.gov (United States)

    De Oliveira, Luciana C.; Olesova, Larisa

    2013-01-01

    This study examined asynchronous online discussions in the online course "English Language Development" to identify themes related to participants' learning about the language and literacy development of English Language Learners when they facilitated online discussions to determine whether the participants developed sufficient…

  19. A newly proposed disease condition produced by light exposure during night: asynchronization.

    Science.gov (United States)

    Kohyama, Jun

    2009-04-01

    The bedtime of preschoolers/pupils/students in Japan has become progressively later with the result sleep duration has become progressively shorter. With these changes, more than half of the preschoolers/pupils/students in Japan recently have complained of daytime sleepiness, while approximately one quarter of junior and senior high school students in Japan reportedly suffer from insomnia. These preschoolers/pupils/students may be suffering from behaviorally induced insufficient sleep syndrome due to inadequate sleep hygiene. If this diagnosis is correct, they should be free from these complaints after obtaining sufficient sleep by avoiding inadequate sleep hygiene. However, such a therapeutic approach often fails. Although social factors are often involved in these sleep disturbances, a novel clinical notion--asynchronization--can further a deeper understanding of the pathophysiology of these disturbances. The essence of asynchronization is a disturbance in various aspects (e.g., cycle, amplitude, phase and interrelationship) of the biological rhythms that normally exhibit circadian oscillation, presumably involving decreased activity of the serotonergic system. The major trigger of asynchronization is hypothesized to be a combination of light exposure during the night and a lack of light exposure in the morning. In addition to basic principles of morning light and an avoidance of nocturnal light exposure, presumable potential therapeutic approaches for asynchronization involve both conventional ones (light therapy, medications (hypnotics, antidepressants, melatonin, vitamin B12), physical activation, chronotherapy) and alternative ones (kampo, pulse therapy, direct contact, control of the autonomic nervous system, respiration (qigong, tanden breathing), chewing, crawling). A morning-type behavioral preference is described in several of the traditional textbooks for good health. The author recommends a morning-type behavioral lifestyle as a way to reduce

  20. Area/latency optimized early output asynchronous full adders and relative-timed ripple carry adders.

    Science.gov (United States)

    Balasubramanian, P; Yamashita, S

    2016-01-01

    This article presents two area/latency optimized gate level asynchronous full adder designs which correspond to early output logic. The proposed full adders are constructed using the delay-insensitive dual-rail code and adhere to the four-phase return-to-zero handshaking. For an asynchronous ripple carry adder (RCA) constructed using the proposed early output full adders, the relative-timing assumption becomes necessary and the inherent advantages of the relative-timed RCA are: (1) computation with valid inputs, i.e., forward latency is data-dependent, and (2) computation with spacer inputs involves a bare minimum constant reverse latency of just one full adder delay, thus resulting in the optimal cycle time. With respect to different 32-bit RCA implementations, and in comparison with the optimized strong-indication, weak-indication, and early output full adder designs, one of the proposed early output full adders achieves respective reductions in latency by 67.8, 12.3 and 6.1 %, while the other proposed early output full adder achieves corresponding reductions in area by 32.6, 24.6 and 6.9 %, with practically no power penalty. Further, the proposed early output full adders based asynchronous RCAs enable minimum reductions in cycle time by 83.4, 15, and 8.8 % when considering carry-propagation over the entire RCA width of 32-bits, and maximum reductions in cycle time by 97.5, 27.4, and 22.4 % for the consideration of a typical carry chain length of 4 full adder stages, when compared to the least of the cycle time estimates of various strong-indication, weak-indication, and early output asynchronous RCAs of similar size. All the asynchronous full adders and RCAs were realized using standard cells in a semi-custom design fashion based on a 32/28 nm CMOS process technology.

  1. 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 ...

  2. 笼型异步磁力耦合器机械特性与试验%Mechanical properties and testing for squirrel cage asynchronous magnetic coupler

    Institute of Scientific and Technical Information of China (English)

    葛研军; 袁直; 贾峰; 杨均悦; 周凯凯

    2016-01-01

    为有效解决目前机械传动系统中选用电机时功率裕度过大而普遍存在的能源利用效率较低问题,提出一种基于三相异步电机鼠笼转子的异步磁力耦合器(squirrel cage asynchronous magnetic coupler,SCAMC).结合SCAMC具体结构特点,采用标量磁位法及二维场边界条件,建立气隙磁场数理模型;在气隙磁通密度中引入时间变量,推导出感生电流随时间变化的表达式;基于电流叠加性,将笼条电流折算到转子表面,并沿圆周方向对感生电流所形成的洛伦兹力进行积分,建立了SCAMC的电磁转矩模型.基于上述理论及技术基础,设计并制造出一台37 kW SCAMC样机,并对其机械特性进行理论计算、仿真验证及试验测试.结果表明:转差率相同时,所得的仿真及试验数据与理论计算值相比,误差不超过5%;SCAMC与同容量的三相异步电机相比,线性工作区更宽,过载能力更强,但其机械特性偏软,可有效缓解负载对电机的冲击.该研究可为磁力耦合器在大惯量、难启动及经常性过载机械设备中的应用提供参考.%In order to effectively solve the problem of the motor's power margin too adequate to ensure the stable operation of the equipment which widely exists in the current mechanical transmission system, a kind of squirrel cage asynchronous magnetic coupler (SCAMC) is proposed based on the principle of three-phase asynchronous motor. The SCAMC has the advantages of the simplicity of mechanical structure, high reliability in successive operation, simple maintenance, weak skin effect of the squirrel cage rotor and adjustable slip ratio and so on. According to the specific characteristics of the SCAMC structure, the mathematical model of air gap magnetic flux density is established by using the scalar magnetic potential method and two-dimensional field boundary conditions. The air gap magnetic flux density generated by the permanent magnet in SCAMC can be decomposed into

  3. 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.

  4. Robustesse d'un contrôle vectoriel de structure minimale d'une machine asynchrone

    Science.gov (United States)

    Ghazel, A.; de Fornel, B.; Hapiot, J. C.

    1996-07-01

    This paper presents a robust speed control of an induction motor (1.5kW/380V) with a reduced computation and additionnel equipment. First a simple direct field-oriented based control law was defined. Then the robustness of the control was investigated and improved by an adaptation of the estimator to voltage harmonics and stator resistance variations, by a robust design of flux and torque controllers and by a feedforward speed control using a load torque observer. A simulation of the hardware architecture and technological characteristics of the experimental structure was developed to define an optimum configuration and to evaluate the control performance limits. Ce travail présente une nouvelle loi de commande robuste aux contraintes matérielles, pour le contrôle vectoriel d'une machine asynchrone (1,5kW/380V) avec un minimum de calcul et d'équipement additionnel. Nous avons défini d'abord un schéma de régulation et un estimateur des grandeurs de commande permettant d'obtenir avec un minimum de traitement numérique un contrôle direct à flux orienté. Puis, nous avons doté cette structure d'une robustesse aux contraintes matérielles par une adaptation de l'estimateur et un dimensionnement robuste de la régulation avec observation du couple de charge. Enfin, pour étudier la faisabilité du contrôle et évaluer ses performances expérimentales, nous avons effectué des simulations fines qui tiennent compte de l'architecture et des caractéristiques technologiques de la structure matérielle.

  5. Adaptation of the EPEC-EM™ Curriculum in a Residency with Asynchronous Learning

    Directory of Open Access Journals (Sweden)

    Gisondi, Michael A

    2010-12-01

    Full Text Available Objective: The Education in Palliative and End-of-life Care for Emergency Medicine Project (EPEC™-EM is a comprehensive curriculum in palliative and end-of-life care for emergency providers. We assessed the adaptation of this course to an EM residency program using synchronous and asynchronous learning.Methods: Curriculum adaptation followed Kern’s standardized six-step curriculum design process. Post-graduate year (PGY 1-4 residents were taught all EPEC™-EM cognitive domains, divided as seven synchronous and seven asynchronous modules. All synchronous modules featured large group didactic lectures and review of EPEC™-EM course materials. Asynchronous modules use only EPEC™-EM electronic course media for resident self-study. Targeted evaluation for EPEC™-EM knowledge objectives was conducted by a prospective case-control crossover study, with synchronous learning serving as the quasi-control, using validated exam tools. We compared de-identified test scores for effectiveness of learning method, using aggregate group performance means for each learning strategy.Results: Of 45 eligible residents 55% participated in a pre-test for local needs analysis, and 78% completed a post-test to measure teaching method effect. Post-test scores improved across all EPEC™-EM domains, with a mean improvement for synchronous modules of +28% (SD=9 and a mean improvement for asynchronous modules of +30% (SD=18. The aggregate mean difference between learning methods was 1.9% (95% CI -15.3, +19.0. Mean test scores of the residents who completed the post-test were: synchronous modules 77% (SD=12; asynchronous modules 83% (SD=13; all modules 80% (SD=12.Conclusion: EPEC™-EM adapted materials can improve resident knowledge of palliative medicine domains, as assessed through validated testing of course objectives. Synchronous and asynchronous learning methods appear to result in similar knowledge transfer, feasibly allowing some course content to be

  6. 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

  7. SEU/SEL Resistant Ultra-Low Power Asynchronous Processor Design for Low-Temperature Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR proposal seeks funding to develop a radiation-hardened circuit architecture to achieve SEU and SEL immunity by using delay-insensitive asynchronous...

  8. Assessment of myocardial adrenergic innervation in patients with sick sinus syndrome: effect of asynchronous ventricular activation from ventricular apical stimulation

    OpenAIRE

    Marketou, M E; Simantirakis, E N; Prassopoulos, V K; Chrysostomakis, S I; Velidaki, A A; Karkavitsas, N S; Vardas, P.E.

    2002-01-01

    Objective: To investigate ventricular sympathetic innervation in patients with sick sinus syndrome and to detect regional deterioration of adrenergic innervation caused by asynchronous ventricular activation from right ventricular pacing.

  9. Synchronization, retiming and OTDM of an asynchronous 10 Gigabit Ethernet NRZ packet using a time lens for Terabit Ethernet

    DEFF Research Database (Denmark)

    Hu, Hao; Laguardia Areal, Janaina; Mulvad, Hans Christian Hansen;

    2011-01-01

    An asynchronous 10G Ethernet packet is synchronized and retimed to a master clock using a time lens. The NRZ packet is converted into an RZ packet and multiplexed with a serial 1.28 Tb/s signal.......An asynchronous 10G Ethernet packet is synchronized and retimed to a master clock using a time lens. The NRZ packet is converted into an RZ packet and multiplexed with a serial 1.28 Tb/s signal....

  10. THE INFLUENCE OF POWER STATOR WINDINGS OF THE ASYNCHRONOUS TRACTION MOTORS FOR DYNAMIC WORKLOAD ELEMENTS OF TRACTION DRIVE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    O. M. Bondarev

    2010-01-01

    Full Text Available The results of studies on determination of loading level of tractive drive elements in some operating conditions, when the values of frequencies of the change of feeding currents of stator windings are to be obtained in both subcritical and ultracritical zones for two types of the tractive gear are presented in the paper.

  11. Introduction to ultrasonic motors

    Energy Technology Data Exchange (ETDEWEB)

    Sashida, Toshiiku; Kenjo, Takashi.

    1993-01-01

    The ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide the motive force. (In conventional electric motors the motive force is electromagnetic.) The result is a motor with unusually good low-speed high-torque and power-to-weight characteristics. It has already found applications in camera autofocus mechanisms, medical equipment subject to high magnetic fields, and motorized car accessories. Its applications will increase as designers become more familiar with its unique characteristics. This book is the result of a collaboration between the inventor and an expert in conventional electric motors: the result is an introduction to the general theory presented in a way that links it to conventional motor theory. It will be invaluable both to motor designers and to those who design with and use electric motors as an introduction to this important new invention.

  12. Chronic motor tic disorder

    Science.gov (United States)

    Chronic vocal tic disorder; Tic - chronic motor tic disorder ... Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start ...

  13. 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.

  14. A New Model for Interference Analysis in Asynchronous Multi-Carrier Transmission

    CERN Document Server

    Medjahdi, Yahia; Ruyet, Didier Le; Roviras, Daniel

    2010-01-01

    Interference at the radio receiver is a key source of degradation in quality of service of wireless communication systems. This paper presents a unified framework for OFDM/FBMC interference characterization and analysis in asynchronous environment. Multi-user interference is caused by the timing synchronization errors which lead to the destruction of the orthogonality between subcarriers. In this paper, we develop a theoretical analysis of the asynchronous interference considering the multi-path effects on the interference signal. We further propose an accurate model for interference that provides a useful computational tool in order to evaluate the performance of an OFDM/FBMC system in a frequency selective fading environment. Finally, simulation results confirmed the accuracy of the proposed model.

  15. Asynchronous Magnetic Bead Rotation (AMBR Microviscometer for Label-Free DNA Analysis

    Directory of Open Access Journals (Sweden)

    Yunzi Li

    2014-03-01

    Full Text Available We have developed a label-free viscosity-based DNA detection system, using paramagnetic beads as an asynchronous magnetic bead rotation (AMBR microviscometer. We have demonstrated experimentally that the bead rotation period is linearly proportional to the viscosity of a DNA solution surrounding the paramagnetic bead, as expected theoretically. Simple optical measurement of asynchronous microbead motion determines solution viscosity precisely in microscale volumes, thus allowing an estimate of DNA concentration or average fragment length. The response of the AMBR microviscometer yields reproducible measurement of DNA solutions, enzymatic digestion reactions, and PCR systems at template concentrations across a 5000-fold range. The results demonstrate the feasibility of viscosity-based DNA detection using AMBR in microscale aqueous volumes.

  16. 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...

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

    DEFF Research Database (Denmark)

    Kasapaki, Evangelia

    . 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...... more flexible timing within its structure, to address signal distribution issues, using a network of synchronous routers. NOCs consist of a switching structure of routers connected by links, with network interfaces (NIs) that connect the processors to the switching structure. Argo uses a novel NI...... design that supports time-predictability, and asynchronous routers that form a time-elastic network. The NI design integrates the DMA functionality and the TDM schedule, and uses dual-ported local memories. The routers combine the router functionality and asynchronous elastic behavior. They also use...

  18. An Almost-Surely Terminating Polynomial Protocol for Asynchronous Byzantine Agreement with Optimal Resilience

    CERN Document Server

    Abraham, Ittai; Halpern, Joseph Y

    2008-01-01

    Consider an asynchronous system with private channels and $n$ processes, up to $t$ of which may be faulty. We settle a longstanding open question by providing a Byzantine agreement protocol that simultaneously achieves three properties: 1. (optimal) resilience: it works as long as $n>3t$ 2. (almost-sure) termination: with probability one, all nonfaulty processes terminate 3. (polynomial) efficiency: the expected computation time, memory consumption, message size, and number of messages sent are all polynomial in $n$. Earlier protocols have achieved only two of these three properties. In particular, the protocol of Bracha is not polynomially efficient, the protocol of Feldman and Micali is not optimally resilient, and the protocol of Canetti and Rabin does not have almost-sure termination. Our protocol utilizes a new primitive called shunning (asynchronous) verifiable secret sharing (SVSS), which ensures, roughly speaking, that either a secret is successfully shared or a new faulty process is ignored from this...

  19. 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...

  20. Sum rates of asynchronous GFDMA and SC-FDMA for 5G uplink

    Directory of Open Access Journals (Sweden)

    Woojin Park

    2015-12-01

    Full Text Available The fifth generation (5G of mobile communication envisions ultralow latency less than 1 ms for radio interface. To this end, frameless asynchronous multiple access may be needed to allow users to transmit instantly without waiting for the next frame start. In this paper, generalized frequency division multiple-access (GFDMA, one of the promising multiple-access candidates for 5G mobile, is compared with the conventional single-carrier FDMA (SC-FDMA in terms of the uplink sum rate when both techniques are adapted for the asynchronous scenario. In particular, a waveform windowing technique is applied to both schemes to mitigate the inter-user interference due to non-zero out-of-band emission.

  1. 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.

  2. 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.

  3. Asynchronous H∞ filtering for linear switched systems with average dwell time

    Science.gov (United States)

    Wang, Bo; Zhang, Hongbin; Wang, Gang; Dang, Chuangyin

    2016-09-01

    This paper is concerned with the H∞ filtering problem for a class of continuous-time linear switched systems with the asynchronous behaviours, where 'asynchronous' means that the switching of the filters to be designed has a lag to the switching of the system modes. By using the Lyapunov-like functions and the average dwell time technique, a sufficient condition is obtained to guarantee the asymptotic stability with a weighted H∞ performance index for the filtering error system. Moreover, the results are formulated in the form of linear matrix inequalities that are numerical feasible. As a result, the filter design problem is solved. Finally, an illustrative numerical example is presented to show the effectiveness of the results.

  4. MMSE Multiuser Detector Alleviating Edge Effect in Asynchronous DS-CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    WANGLing; JIAOLicheng; TAOHaihong; LIUFang

    2005-01-01

    Multiuser detection is a key technique in DS-CDMA systems. At the base station, the received signal is the compositive signal transmitted by active users in the system over asynchronous channels, the Multiple access interference (MAI) components of which is more serious than that in synchronous systems. In this paper, based on the compact matrix signal model of the asynchronous system, a MMSE (Minimum mean square error) Multiuser detector alleviating edge effect (MMSEAEE) with low complexity is proposed. The asymptotic efficiency, near-far effect resistance and computational complexity of the multiuser detector are analyzed qualitatively. Finally, the bit error rate is simulated via plentiful Monte Carlo numerical experiments. With performance analysis and numerical simulation, it is shown that MMSEAEE with low complexity offers significant performance improvement over some existing popular detectors in eliminating multiple access interference and near-far resistance.

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

    Directory of Open Access Journals (Sweden)

    F. Khammar

    2016-01-01

    Full Text Available 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 challenge for researchers. This criterion can be satisfied only by applying advanced techniques of command. After mathematical modeling of the asynchronous machine, it defines the control strategies based on the orientation of the rotor flux. The results of the different simulation tests highlight the properties of robustness of algorithms proposed and suggested to compare the different control strategies.

  6. 基于Javascript的异步编程分析%Javascript-based Asynchronous Programming Analysis

    Institute of Scientific and Technical Information of China (English)

    陈浩

    2015-01-01

    异步编程带来的问题在客户端Javascript中并不明显,但随着服务器端Javascript越来越广的被使用,大量的异步IO操作使得该问题变得明显。许多不同的方法都可以解决这个问题,本文针对此问题讨论了一些方法。%Asynchronous programming problems caused by the client Javascript is not obvious, but with the server-side Javascript is used more widely, a large number of asynchronous IO operation so that the problem becomes apparent. Many different methods can solve this problem, this paper discusses some of the ways this problem.

  7. Asynchronous cellular automaton-based neuron: theoretical analysis and on-FPGA learning.

    Science.gov (United States)

    Matsubara, Takashi; Torikai, Hiroyuki

    2013-05-01

    A generalized asynchronous cellular automaton-based neuron model is a special kind of cellular automaton that is designed to mimic the nonlinear dynamics of neurons. The model can be implemented as an asynchronous sequential logic circuit and its control parameter is the pattern of wires among the circuit elements that is adjustable after implementation in a field-programmable gate array (FPGA) device. In this paper, a novel theoretical analysis method for the model is presented. Using this method, stabilities of neuron-like orbits and occurrence mechanisms of neuron-like bifurcations of the model are clarified theoretically. Also, a novel learning algorithm for the model is presented. An equivalent experiment shows that an FPGA-implemented learning algorithm enables an FPGA-implemented model to automatically reproduce typical nonlinear responses and occurrence mechanisms observed in biological and model neurons.

  8. Single-phase PM synchronous motor simulation with Matlab/Simulink

    Science.gov (United States)

    Chiver, O.; Neamt, L.; Pop, E.; Horgos, M.; Erdei, Z.; Pop-Vadean, A.; Pop, P. P.

    2017-01-01

    The permanent magnet (PM) synchronous motors have a major advantage compared to the asynchronous motors, namely that there are no losses in the rotor. As regarding the single-phase motors must be considered the possibility to obtain the starting torque. A simple and inexpensive constructive solution is the motor with tapered air-gap, which can develop a starting torque (although specific starting torque is small) in a well-defined direction, simply by powering the stator winding from the network of industrial frequency. Starting torque occurs due to the fact that the axis of the rotor field created by PM in the rest position differs from the axis of the stator because of the tapered air gap. Therefore this motor is more often used in low power household appliances. The development and the implementation in Matlab / Simulink of the motor model will be presented in this paper. The model is based on a mathematical model with lumped parameters, parameters that are determined through calculations and finite elements analysis. The motor behavior will be studied, both in stationary and dynamic operation. The accuracy of the model is verified by comparing simulation results with results obtained by measurements.

  9. 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.

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

    DEFF Research Database (Denmark)

    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 ......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 problem with harmonic currents, when using a single phase network connection, can be solved....

  11. Piezoelectric Motors, an Overview

    OpenAIRE

    Karl Spanner; Burhanettin Koc

    2016-01-01

    Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ult...

  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. 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.

  14. Interference tables: a useful model for interference analysis in asynchronous multicarrier transmission

    OpenAIRE

    Medjahdi, Yahia; Terré, Michel; Le Ruyet, Didier; Roviras, Daniel

    2014-01-01

    In this paper, we investigate the impact of timing asynchronism on the performance of multicarrier techniques in a spectrum coexistence context. Two multicarrier schemes are considered: cyclic prefix-based orthogonal frequency division multiplexing (CP-OFDM) with a rectangular pulse shape and filter bank-based multicarrier (FBMC) with physical layer for dynamic spectrum access and cognitive radio (PHYDYAS) and isotropic orthogonal transform algorithm (IOTA) waveforms. First, we present the ge...

  15. A New Parallel Algorithm in Power Flow Calculation: Dynamic Asynchronous Parallel Algorithm

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the general methods in power flow calculation of power system and onconceptions and classifications of parallel algorithm, a new approach named DynamicAsynchronous Parallel Algorithm that applies to the online analysis and real-time dispatching and controlling of large-scale power network was put forward in this paper. Its performances of high speed and dynamic following have been verified on IEEE-14 bus system.

  16. A CLASS OF ASYNCHRONOUS PARALLEL MULTISPLITTING RELAXATION METHODS FOR LARGE SPARSE LINEAR COMPLEMENTARITY PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Zhong-zhi Bai; Yu-guang Huang

    2003-01-01

    Asynchronous parallel multisplitting relaxation methods for solving large sparse linear complementarity problems are presented, and their convergence is proved when the system matrices are H-matrices having positive diagonal elements. Moreover, block and multi-parameter variants of the new methods, together with their convergence properties,are investigated in detail. Numerical results show that these new methods can achieve high parallel efficiency for solving the large sparse linear complementarity problems on multiprocessor systems.

  17. All optical contention detection and resolution for asynchronous variable length optical packets switching

    Science.gov (United States)

    Farhat, Rim; Farhat, Amel; Menif, Mourad

    2016-04-01

    We proposed a novel 2×2 all optical packet switching router architecture supporting asynchronous, labelled and variablelength packet. A proof of concept through Matlab Simulink simulation is validated. Then we discussed the three possible scenarios to demonstrate the contention resolution technique based on deflection routing. We have showing that the contending packet is detected and forwarded according FIFO (First In First Out) strategy to another output.

  18. Framework for virtual collaboration emphasized by awareness information and asynchronous interaction

    OpenAIRE

    Matsuda, Tomo; Shibata,Naoki; Yasumoto, keiichi; Ito, Minoru

    2008-01-01

    In this paper, we propose a framework which allows remote users to form conversation groups based on spatial relationship in a shared virtual space. Our proposed framework can transport awareness information of real world by capturing and transferring user’s audio visual information. Our framework also provides functions useful to CSCW, which allow each user to simultaneously join different conversation groups, and communicate with others asynchronously exchanging awareness information. We sh...

  19. 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.

  20. Asynchronous Periodic Edge-Event Triggered Control for Double-Integrator Networks With Communication Time Delays.

    Science.gov (United States)

    Duan, Gaopeng; Xiao, Feng; Wang, Long

    2017-01-23

    This paper focuses on the average consensus of double-integrator networked systems based on the asynchronous periodic edge-event triggered control. The asynchronous property lies in the edge event-detecting procedure. For different edges, their event detections are performed at different times and the corresponding events occur independently of each other. When an event is activated, the two adjacent agents connected by the corresponding link sample their relative state information and update their controllers. The application of incidence matrix facilitates the transformation of control objects from the agent-based to the edge-based. Practically, due to the constraints of network bandwidth and communication distance, agents usually cannot receive the instantaneous information of some others, which has an impact on the system performance. Hence, it is necessary to investigate the presence of communication time delays. For double-integrator multiagent systems with and without communication time delays, the average state consensus can be asynchronously achieved by designing appropriate parameters under the proposed event-detecting rules. The presented results specify the relationship among the maximum allowable time delays, interaction topologies, and event-detecting periods. Furthermore, the proposed protocols have the advantages of reduced communication costs and controller-updating costs. Simulation examples are given to illustrate the proposed theoretical results.

  1. 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.

  2. 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.

  3. 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.

  4. Learning Management System Development with Application of Asynchronous Learning Method in STMIK IBBI Medan

    Directory of Open Access Journals (Sweden)

    Marwa Halim

    2015-10-01

    Full Text Available This article will explain asynchronous learn- ing system using attractive discussion forums and video teaching materials features for user so that the devel- opment of both features will increase e-learning system usage by students and lecturers which can eventually im- prove the students’ absorption on the provided teaching materials, increase the active participation of students, improve self-learning ability, and to improve the quality of learning materials. The method used in this study by distributing questionnaires in online form to stakeholders users consisting of lecturers and students with the num- ber of respondents is 225 people and author use model ADDIE which focuses on Analysis, Design, Development, Implementation and Evaluation as development design. Results of this study is an application of web-based asynchronous learning which can be used by students and lecturers with the results of the application evaluation is based on a survey to students and lecturers. From this study, can be concluded that to support online learning with asynchronous method using the video learning feature in online lecture needs to be developed in order to support the science transformation process from lecturers to students. Attractive video teaching  materials  model for students has characteristics such as screen shots and presentation models.

  5. A Low-Power Asynchronous Step-Down DC-DC Converter for Implantable Devices.

    Science.gov (United States)

    Al-Terkawi Hasib, Omar; Sawan, M; Savaria, Y

    2011-06-01

    In this paper, we present a fully integrated asynchronous step-down switched capacitor dc-dc conversion structure suitable for supporting ultra-low-power circuits commonly found in biomedical implants. The proposed converter uses a fully digital asynchronous state machine as the heart of the control circuitry to generate the drive signals. To minimize the switching losses, the asynchronous controller scales the switching frequency of the drive signals according to the loading conditions. It also turns on additional parallel switches when needed and has a backup synchronous drive mode. This circuit regulates load voltages from 300 mV to 1.1 V derived from a 1.2-V input voltage. A total of 350 pF on-chip capacitance was implemented to support a maximum of 230-μ W load power, while providing efficiency up to 80%. The circuit validating the proposed concepts was fabricated in 0.13- μm complementary metal-oxide semiconductor technology. Experimental test results confirm the expected functionality and performance of the proposed circuit.

  6. A Methodology for the Design and Verification of Globally Asynchronous/Locally Synchronous Architectures

    Science.gov (United States)

    Miller, Steven P.; Whalen, Mike W.; O'Brien, Dan; Heimdahl, Mats P.; Joshi, Anjali

    2005-01-01

    Recent advanced in model-checking have made it practical to formally verify the correctness of many complex synchronous systems (i.e., systems driven by a single clock). However, many computer systems are implemented by asynchronously composing several synchronous components, where each component has its own clock and these clocks are not synchronized. Formal verification of such Globally Asynchronous/Locally Synchronous (GA/LS) architectures is a much more difficult task. In this report, we describe a methodology for developing and reasoning about such systems. This approach allows a developer to start from an ideal system specification and refine it along two axes. Along one axis, the system can be refined one component at a time towards an implementation. Along the other axis, the behavior of the system can be relaxed to produce a more cost effective but still acceptable solution. We illustrate this process by applying it to the synchronization logic of a Dual Fight Guidance System, evolving the system from an ideal case in which the components do not fail and communicate synchronously to one in which the components can fail and communicate asynchronously. For each step, we show how the system requirements have to change if the system is to be implemented and prove that each implementation meets the revised system requirements through modelchecking.

  7. 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.

  8. ASYNCHRONOUS COMPUTER-MEDIATED CORRECTIVE FEEDBACK AND THE CORRECT USE OF PREPOSITIONS: Is It Really Effective?

    Directory of Open Access Journals (Sweden)

    Seyyed Behrooz HOSSEINI

    2012-08-01

    Full Text Available An area that has recently attracted increasing attention is providing feedback on learners’ writing accuracy through the Internet. However, research in this area has largely focused on synchronous communication, i.e., chatting, with fewer studies assessing asynchronous technologies, i.e., e-mailing. Therefore, this study investigates the effectiveness of asynchronous computer-mediated corrective feedback-explicit and implicit, on increasing the correct use of prepositions. Forty-five Iranian elementary EFL learners at the ILI in Tehran were randomly assigned to two experimental groups, receiving explicit and implicit corrective feedback respectively, and one control group receiving no corrective feedback. Each group included 15 participants. After the treatment, a post-test was administered to assess the probable increase in the correct use of prepositions for the experimental groups compared to the control group. Analysis of the results through a one-way ANOVA revealed that the experimental group 1 who received explicit corrective feedback significantly outperformed the experimental group 2 and the control group. The experimental group 2 who received implicit corrective feedback showed no significant improvement over the experimental group 1 and the control group. Computer-mediated communication, asynchronous CMC, synchronous CMC, the Internet, corrective feedback, e-mail, chat. Although the findings support the current view on feedback through technology, due to the scarcity of research, more investigation is merited as there is much to gain regarding this burgeoning field.

  9. Efficiency increase of a high-efficient IEC 3 kW permanent-magnet-motor - Implementation in a pump system; Effizienzsteigerung eines hocheffizienten IEC 3 kW Permanent-Magnet-Motors inklusiv energetische Messung als Pumpenanwendung - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M. [Circle Motor AG, Guemligen (Switzerland); Biner, H.-P.; Evequoz, B. [University of Applied Sciences, Western Switzerland, Delemont (Switzerland); Salathe, D. [Fachhochschule Luzern, Technik und Architektur, Horw (Switzerland)

    2009-11-15

    The IEC norm 60034-30 defines new international standards for efficiency of electric motors. IE1 is standard efficiency, IE2 is high efficiency, and IE3/IE4 are the premium class. Circle Motor AG assumes that the premium class efficiency factor for motors with power less than 22 kW is easier to achieve with Permanent-Magnet-Motors enhanced by electric inverters than with asynchronous motors. The goal of this work is to achieve an overall 'efficiency factor' of 90% through a high-efficiency 3 kW-rated input Permanent-Magnet-Motor enhanced with an electric inverter, and then to perform measurements on the pump drive. The 'efficiency factor' measurement results showed worse performance than expected for both the inverter and the motor. One reason is due to high iron losses in the motor that are produced by high frequency currents of inverter. Another reason is the relatively high ohmic resistance of the copper motor winding caused by the chosen coil production method. By filtering high frequency currents at the rated power, the motor efficiency factor reaches up to 89.5%, which complies with premium class IE3. In generator mode the efficiency reaches 92.8%. We note that the positive result of this work is that the inverter can be produced with very low standby power losses - in our current work with 160 mW. It is necessary to admit that every detail can be responsible for success or failure during research and development activities of premium class motors. The optimization activities mainly belong to the area of additional losses of electric machines. In this report we have encountered all research results on the theme of Additional Losses that resulted from the current research work. The concept of drive control from the previous research project has shown itself as efficiency aware. The total efficiency factor of 90% can be reached by a system coupling a drive controller with a synchronous motor and the 'know how' from this work. The

  10. Solid propellant motor

    Science.gov (United States)

    Shafer, J. I.; Marsh, H. E., Jr. (Inventor)

    1978-01-01

    A case bonded end burning solid propellant rocket motor is described. A propellant with sufficiently low modulus to avoid chamber buckling on cooling from cure and sufficiently high elongation to sustain the stresses induced without cracking is used. The propellant is zone cured within the motor case at high pressures equal to or approaching the pressure at which the motor will operate during combustion. A solid propellant motor with a burning time long enough that its spacecraft would be limited to a maximum acceleration of less than 1 g is provided by one version of the case bonded end burning solid propellant motor of the invention.

  11. 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.

  12. A Reconfigurable Stepping Motor

    Science.gov (United States)

    Rogers, Charles; Selvaggi, Richard

    2009-04-01

    Multiphase brushless actuators, commonly known as the stepper motors, are ubiquitous for many precision control applications. Developments in the microelectronics have lead to their use as efficient drive motors for modern electric vehicles. Understanding the physics and the control logic for interfacing these transducers continues to be important for scientists and engineers. An overview of the stepping motor principles and interfacing requirements is presented and a simple working model used to teach the concepts of stepper motors is described and demonstrated. This model was used to design a much larger stepper motor required to precisely rotate a massive optical system in the undergraduate advanced physics laboratory.

  13. 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.  

  14. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    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.

  15. Neuroplasticity & Motor Learning

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye

    Practice of a new motor task is usually associated with an improvement in performance. Indeed, if we stop practicing and return the next day to the same task, we find that our performance has been maintained and may even be better than it was at the start of the first day. This improvement...... is a 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 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 our...

  16. Piezoelectric Motors, an Overview

    Directory of Open Access Journals (Sweden)

    Karl Spanner

    2016-02-01

    Full Text Available Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ultrasonic motors, inertia-drive, and piezo-walk-drive. In this review, a comprehensive summary of piezoelectric motors, with their classification from initial idea to recent progress, is presented. This review also includes some of the industrial and commercial applications of piezoelectric motors that are presently available in the market as actuators.

  17. Simulation of Induction Motor Vector Inverter Control System%异步电机矢量变频控制系统的仿真

    Institute of Scientific and Technical Information of China (English)

    郑永范; 董永考; 孟维良; 吴新方

    2016-01-01

    This article is based on asynchronous motor vector control system for the study,the mathematical basis of the model of induction motor,using rotor field oriented control,field control and torque control com-pletely decoupled,the simulation model,and the model is applied to the asynchronous motor the startup process and increase load speed process to speed,torque and stator current feature quantity,the simulation results of the asynchronous motor starting and speed obtained on vector control method of induction motor were studied,complete the induction motor vector control dynamic simulation.%该文是以异步电机矢量控制系统为研究对象,在异步电机的数学模型基础上,采用转子磁场定向控制,磁场控制与转矩控制完全解耦,建立了仿真模型,并把该模型应用于异步电动机的启动过程中及加负载调速过程中,以转速、转矩和定子电流为特征量,通过对异步电动机的启动和调速得到的仿真结果,对异步电机的矢量控制方法进行了研究,从而达到了对异步电动机的矢量控制动态仿真的目的。

  18. 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

  19. Experimental Study of Brushless Doubly-Fed Machine With Cage Rotor at the Asynchronous Operation Mode%笼型转子无刷双馈电机异步运行模式的实验研究

    Institute of Scientific and Technical Information of China (English)

    杜江; 韩力; 欧先朋; 韩雪峰

    2016-01-01

    By changing the control winding connection and feeding method of brushless doubly-fed machine (BDFM), many different operation modes can be obtained, such as asynchronous, synchronous, doubly-fed sub-synchronous and super-synchronous models. However, the detailed research about the asynchronous operation mode of BDFM is seldom. The concepts of “singly-fed asynchronous” and “doubly-fed asynchronous” operation modes were proposed. The basic electromagnetic relationship of these asynchronous operation modes were described in detail based on the features of BDFM with cage rotor. The air-gap magnetic field waveforms were analyzed by finite element, which verified that the constant electromagnetic torque could be produced at two different asynchronous operation modes. The results of finite element analysis and the comparisons of the test data show that the operating characteristics of BDFM singly-fed asynchronous mode are similar with induction motor, the speed still meet the characteristics of BDFM and can be adjusted by changing the external series resistance of control winding at doubly-fed asynchronous operation mode. The results can provide reference for studying the operation rules of BDFM in the further.%无刷双馈电机(brushless doubly-fed machine,BDFM)通过改变控制绕组的联接与馈电方式,可实现异步、同步、双馈亚同步和超同步等多种不同运行方式。然而,目前尚缺乏对BDFM异步运行模式的详细研究。该文提出了BDFM“单馈异步”和“双馈异步”运行模式的概念,结合笼型转子 BDFM的特点,阐述了两种异步运行模式的基本电磁关系,利用有限元分析得到了 BDFM 样机的气隙磁场波形,从而验证了两种运行模式均能产生恒定电磁转矩。通过对BDFM 样机在两种异步运行模式下的有限元分析和实验数据对比,表明 BDFM 单馈异步运行模式与普通异步电动机的运行特性相类似,在双馈异步运

  20. Investigation on the spectral properties of 2D asynchronous fluorescence spectra generated by using variable excitation wavelengths as a perturbation

    Science.gov (United States)

    Wang, Jingdan; He, Anqi; Guo, Ran; Wei, Yongju; Feng, Juan; Xu, Yizhuang; Noda, Isao; Wu, Jinguang

    2016-11-01

    Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane. When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.

  1. An Asynchronous Low Power and High Performance VLSI Architecture for Viterbi Decoder Implemented with Quasi Delay Insensitive Templates.

    Science.gov (United States)

    Devi, T Kalavathi; Palaniappan, Sakthivel

    2015-01-01

    Convolutional codes are comprehensively used as Forward Error Correction (FEC) codes in digital communication systems. For decoding of convolutional codes at the receiver end, Viterbi decoder is often used to have high priority. This decoder meets the demand of high speed and low power. At present, the design of a competent system in Very Large Scale Integration (VLSI) technology requires these VLSI parameters to be finely defined. The proposed asynchronous method focuses on reducing the power consumption of Viterbi decoder for various constraint lengths using asynchronous modules. The asynchronous designs are based on commonly used Quasi Delay Insensitive (QDI) templates, namely, Precharge Half Buffer (PCHB) and Weak Conditioned Half Buffer (WCHB). The functionality of the proposed asynchronous design is simulated and verified using Tanner Spice (TSPICE) in 0.25 µm, 65 nm, and 180 nm technologies of Taiwan Semiconductor Manufacture Company (TSMC). The simulation result illustrates that the asynchronous design techniques have 25.21% of power reduction compared to synchronous design and work at a speed of 475 MHz.

  2. Isolation of TRPV1 independent mechanisms of spontaneous and asynchronous glutamate release at primary afferent to NTS synapses.

    Science.gov (United States)

    Fenwick, Axel J; Wu, Shaw-Wen; Peters, James H

    2014-01-01

    Cranial visceral afferents contained within the solitary tract (ST) contact second-order neurons in the nucleus of the solitary tract (NTS) and release the excitatory amino acid glutamate via three distinct exocytosis pathways; synchronous, asynchronous, and spontaneous release. The presence of TRPV1 in the central terminals of a majority of ST afferents conveys activity-dependent asynchronous glutamate release and provides a temperature sensitive calcium conductance which largely determines the rate of spontaneous vesicle fusion. TRPV1 is present in unmyelinated C-fiber afferents and these facilitated forms of glutamate release may underlie the relative strength of C-fibers in activating autonomic reflex pathways. However, pharmacological blockade of TRPV1 signaling eliminates only ~50% of the asynchronous profile and attenuates the temperature sensitivity of spontaneous release indicating additional thermosensitive calcium influx pathways may exist which mediate these forms of vesicle release. In the present study we isolate the contribution of TRPV1 independent forms of glutamate release at ST-NTS synapses. We found ST afferent innervation at NTS neurons and synchronous vesicle release from TRPV1 KO mice was not different to control animals; however, only half of TRPV1 KO ST afferents completely lacked asynchronous glutamate release. Further, temperature driven spontaneous rates of vesicle release were not different from 33 to 37°C between control and TRPV1 KO afferents. These findings suggest additional temperature dependent mechanisms controlling asynchronous and thermosensitive spontaneous release at physiological temperatures, possibly mediated by additional thermosensitive TRP channels in primary afferent terminals.

  3. Modularity for Motor Control and Motor Learning.

    Science.gov (United States)

    d'Avella, Andrea

    2016-01-01

    How the central nervous system (CNS) overcomes the complexity of multi-joint and multi-muscle control and how it acquires or adapts motor skills are fundamental and open questions in neuroscience. A modular architecture may simplify control by embedding features of both the dynamic behavior of the musculoskeletal system and of the task into a small number of modules and by directly mapping task goals into module combination parameters. Several studies of the electromyographic (EMG) activity recorded from many muscles during the performance of different tasks have shown that motor commands are generated by the combination of a small number of muscle synergies, coordinated recruitment of groups of muscles with specific amplitude balances or activation waveforms, thus supporting a modular organization of motor control. Modularity may also help understanding motor learning. In a modular architecture, acquisition of a new motor skill or adaptation of an existing skill after a perturbation may occur at the level of modules or at the level of module combinations. As learning or adapting an existing skill through recombination of modules is likely faster than learning or adapting a skill by acquiring new modules, compatibility with the modules predicts learning difficulty. A recent study in which human subjects used myoelectric control to move a mass in a virtual environment has tested this prediction. By altering the mapping between recorded muscle activity and simulated force applied on the mass, as in a complex surgical rearrangement of the tendons, it has been possible to show that it is easier to adapt to a perturbation that is compatible with the muscle synergies used to generate hand force than to a similar but incompatible perturbation. This result provides direct support for a modular organization of motor control and motor learning.

  4. ELECTRIC MOTOR CARS.

    Science.gov (United States)

    PASSENGER VEHICLES , ELECTRIC MOTORS), FEASIBILITY STUDIES, BATTERY COMPONENTS, ELECTRIC BATTERIES, FUEL CELLS, ENERGY CONVERSION, NUCLEAR ENERGY, THERMIONIC CONVERTERS , THERMOELECTRICITY, POWER EQUIPMENT, COSTS

  5. Fast Simulation of Mechanical Heterogeneity in the Electrically Asynchronous Heart Using the MultiPatch Module.

    Directory of Open Access Journals (Sweden)

    John Walmsley

    2015-07-01

    Full Text Available Cardiac electrical asynchrony occurs as a result of cardiac pacing or conduction disorders such as left bundle-branch block (LBBB. Electrically asynchronous activation causes myocardial contraction heterogeneity that can be detrimental for cardiac function. Computational models provide a tool for understanding pathological consequences of dyssynchronous contraction. Simulations of mechanical dyssynchrony within the heart are typically performed using the finite element method, whose computational intensity may present an obstacle to clinical deployment of patient-specific models. We present an alternative based on the CircAdapt lumped-parameter model of the heart and circulatory system, called the MultiPatch module. Cardiac walls are subdivided into an arbitrary number of patches of homogeneous tissue. Tissue properties and activation time can differ between patches. All patches within a wall share a common wall tension and curvature. Consequently, spatial location within the wall is not required to calculate deformation in a patch. We test the hypothesis that activation time is more important than tissue location for determining mechanical deformation in asynchronous hearts. We perform simulations representing an experimental study of myocardial deformation induced by ventricular pacing, and a patient with LBBB and heart failure using endocardial recordings of electrical activation, wall volumes, and end-diastolic volumes. Direct comparison between simulated and experimental strain patterns shows both qualitative and quantitative agreement between model fibre strain and experimental circumferential strain in terms of shortening and rebound stretch during ejection. Local myofibre strain in the patient simulation shows qualitative agreement with circumferential strain patterns observed in the patient using tagged MRI. We conclude that the MultiPatch module produces realistic regional deformation patterns in the asynchronous heart and that

  6. 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.

  7. Participation in asynchronous online discussion forums does improve student learning of gross anatomy.

    Science.gov (United States)

    Green, Rodney A; Farchione, Davide; Hughes, Diane L; Chan, Siew-Pang

    2014-01-01

    Asynchronous online discussion forums are common in blended learning models and are popular with students. A previous report has suggested that participation in these forums may assist student learning in a gross anatomy subject but it was unclear as to whether more academically able students post more often or whether participation led to improved learning outcomes. This study used a path model to analyze the contribution of forum participation, previous academic ability, and student campus of enrolment to final marks in a multicampus gross anatomy course for physiotherapy students. The course has a substantial online learning management system (LMS) that incorporates asynchronous forums as a learning tool, particularly to answer learning objectives. Students were encouraged to post new threads and answer queries in threads started by others. The forums were moderated weekly by staff. Discussion forums were the most used feature of the LMS site with 31,920 hits. Forty-eight percent of the students posted at least once with 186 threads initiated by students and a total of 608 posts. The total number of posts made a significant direct contribution to final mark (P = 0.008) as did previous academic ability (P = 0.002). Although campus did not contribute to final mark, there was a trend for students at the campus where the course coordinator was situated to post more often than those at the other campus (P = 0.073). These results indicate that asynchronous online discussion forums can be an effective tool for improving student learning outcomes as evidenced by final marks in gross anatomy teaching.

  8. 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.

  9. 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.

  10. Full flex-grid asynchronous multiplexing demonstrated with Nyquist pulse-shaping.

    Science.gov (United States)

    Schindler, P C; Schmogrow, R; Wolf, S; Baeuerle, B; Nebendahl, B; Koos, C; Freude, W; Leuthold, J

    2014-05-01

    We demonstrate full flex-grid operation with Nyquist frequency division multiplexing. The technique supports high spectral efficiency, asynchronous operation of channels, variable channel loading with different modulation formats and dynamic bandwidth allocation. Data from different sources with different bit and symbol rates are encoded onto electrical Nyquist pulses with different electrical subcarrier frequencies, and then transmitted optically. We give details on the transceiver design with digital signal processing and investigate the implementation penalty as a function of several design parameters such as limited filter length and effective number of bits. Finally, experiments are performed for receivers with direct detection, intradyne and remote heterodyne reception.

  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...... to 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....

  12. 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.

  13. Proximity-Based Asynchronous Messaging Platform for Location-Based Internet of Things Service

    Directory of Open Access Journals (Sweden)

    Hyeong gon Jo

    2016-07-01

    Full Text Available The Internet of Things (IoT opens up tremendous opportunities to provide location-based applications. However, despite the services around a user being physically adjacent, common IoT platforms use a centralized structure, like a cloud-computing architecture, which transfers large amounts of data to a central server. This raises problems, such as traffic concentration, long service latency, and high communication cost. In this paper, we propose a physical distance-based asynchronous messaging platform that specializes in processing personalized data and location-based messages. The proposed system disperses traffic using a location-based message-delivery protocol, and has high stability.

  14. Specification and verification of gate-level VHDL models of synchronous and asynchronous circuits

    Science.gov (United States)

    Russinoff, David M.

    1995-01-01

    We present a mathematical definition of hardware description language (HDL) that admits a semantics-preserving translation to a subset of VHDL. Our HDL includes the basic VHDL propagation delay mechanisms and gate-level circuit descriptions. We also develop formal procedures for deriving and verifying concise behavioral specifications of combinational and sequential devices. The HDL and the specification procedures have been formally encoded in the computational logic of Boyer and Moore, which provides a LISP implementation as well as a facility for mechanical proof-checking. As an application, we design, specify, and verify a circuit that achieves asynchronous communication by means of the biphase mark protocol.

  15. Chroma key without color restrictions based on asynchronous amplitude modulation of background illumination on retroreflective screens

    Science.gov (United States)

    Vidal, Borja; Lafuente, Juan A.

    2016-03-01

    A simple technique to avoid color limitations in image capture systems based on chroma key video composition using retroreflective screens and light-emitting diodes (LED) rings is proposed and demonstrated. The combination of an asynchronous temporal modulation onto the background illumination and simple image processing removes the usual restrictions on foreground colors in the scene. The technique removes technical constraints in stage composition, allowing its design to be purely based on artistic grounds. Since it only requires adding a very simple electronic circuit to widely used chroma keying hardware based on retroreflective screens, the technique is easily applicable to TV and filming studios.

  16. Renewal Approach to the Analysis of the Asynchronous State for Coupled Noisy Oscillators

    CERN Document Server

    Farkhooi, Farzad

    2015-01-01

    We develop a framework in which the activity of nonlinear pulse-coupled oscillators is posed within the renewal theory. In this approach, the evolution of inter-event density allows for a self-consistent calculation that determines the asynchronous state and its stability. This framework, can readily be extended to the analysis of systems with more state variables. To exhibit this, we study a nonlinear pulse-coupled system, where couplings are dynamic and activity dependent. We investigate stability of this system and we show it undergoes a super-critical Hopf bifurcation to collective synchronization.

  17. 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.

  18. 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.

  19. Internal end-effect problem in a linear asynchronous MHD machine with arbitrary current load

    Energy Technology Data Exchange (ETDEWEB)

    Vilnitis, A.Ya.

    1977-01-01

    The internal end-effect problem in a bilateral linear asynchronous engine is solved by variation of constants for a surface current load of any type, including discrete conductors. Mathematically correct formulae for this case are given for computing the mechanical force on wound coils and the active power. Known methods of end-effect compensation are examined. The requirements for the surface load of inductors were found for the case where the requirements may be limited to an internal problem and scattering along the magnetic circuit ends.

  20. 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

    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 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...

  1. 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.

  2. Clonal expansion and linear genome evolution through breast cancer progression from pre-invasive stages to asynchronous metastasis

    DEFF Research Database (Denmark)

    Krøigård, Anne Bruun; Larsen, Martin Jakob; Lænkholm, Anne Vibeke;

    2015-01-01

    Evolution of the breast cancer genome from pre-invasive stages to asynchronous metastasis is complex and mostly unexplored, but highly demanded as it may provide novel markers for and mechanistic insights in cancer progression. The increasing use of personalized therapy of breast cancer necessita......Evolution of the breast cancer genome from pre-invasive stages to asynchronous metastasis is complex and mostly unexplored, but highly demanded as it may provide novel markers for and mechanistic insights in cancer progression. The increasing use of personalized therapy of breast cancer...... progression from one breast cancer patient, including two different regions of Ductal Carcinoma In Situ (DCIS), primary tumor and an asynchronous metastasis. We identify a remarkable landscape of somatic mutations, retained throughout breast cancer progression and with new mutational events emerging at each...

  3. 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 similar, whereas hypothesis (b) predicts that they are different. In this fMRI study, healthy subjects saw visual cursor movement that was either synchronous or asynchronous with their active or passive finger movements. The aim was to identify the brain areas where the neural activity depended on whether...

  4. 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 similar, whereas hypothesis (b) predicts that they are different. In this fMRI study, healthy subjects saw visual cursor movement that was either synchronous or asynchronous with their active or passive finger movements. The aim was to identify the brain areas where the neural activity depended on whether...

  5. 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.

  6. Modeling Induction Motor Imbalances

    DEFF Research Database (Denmark)

    Armah, Kabenla; Jouffroy, Jerome; Duggen, Lars

    2016-01-01

    This paper gives a study into the development of a generalized model for a three-phase induction motor that offers flexibility of simulating balanced and unbalanced parameter scenarios. By analyzing the interaction of forces within the motor, we achieve our main objective of deriving the system...

  7. Accelerator physics studies on the effects from an asynchronous beam dump onto the LHC experimental region collimators

    CERN Document Server

    Lari, L; Boccone, V; Bruce, R; Cerutti, F; Rossi, A; Vlachoudis, V; Mereghetti, A; Faus-Golfe, A

    2012-01-01

    Asynchronous beam aborts at the LHC are estimated to occur on average once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their tungsten-based active jaw insert has a lower damage threshold than the carbon-based other LHC collimators. Settings of the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.

  8. 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 anomalies...

  9. Induction motor control

    Science.gov (United States)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  10. Induction motor control

    Science.gov (United States)

    Hansen, Irving G.

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  11. Sensor placement on Canton Tower for health monitoring using asynchronous-climb monkey algorithm

    Science.gov (United States)

    Yi, Ting-Hua; Li, Hong-Nan; Zhang, Xu-Dong

    2012-12-01

    Heuristic optimization algorithms have become a popular choice for solving complex and intricate sensor placement problems which are difficult to solve by traditional methods. This paper proposes a novel and interesting methodology called the asynchronous-climb monkey algorithm (AMA) for the optimum design of sensor arrays for a structural health monitoring system. Different from the existing algorithms, the dual-structure coding method is designed and adopted for the representation of the design variables. The asynchronous-climb process is incorporated in the proposed AMA that can adjust the trajectory of each individual dynamically in the search space according to its own experience and other monkeys. The concept of ‘monkey king’ is introduced in the AMA, which reflects the Darwinian principle of natural selection and can create an interaction network to correctly guide the movement of other monkeys. Numerical experiments are carried out using two different objective functions by considering the Canton Tower in China with or without the antenna mast to evaluate the performance of the proposed algorithm. Investigations have indicated that the proposed AMA exhibits faster convergence characteristics and can generate sensor configurations superior in all instances when compared to the conventional monkey algorithm. For structures with stiffness mutation such as the Canton Tower, the sensor placement needs to be considered for each part separately.

  12. Interference tables: a useful model for interference analysis in asynchronous multicarrier transmission

    Science.gov (United States)

    Medjahdi, Yahia; Terré, Michel; Ruyet, Didier Le; Roviras, Daniel

    2014-12-01

    In this paper, we investigate the impact of timing asynchronism on the performance of multicarrier techniques in a spectrum coexistence context. Two multicarrier schemes are considered: cyclic prefix-based orthogonal frequency division multiplexing (CP-OFDM) with a rectangular pulse shape and filter bank-based multicarrier (FBMC) with physical layer for dynamic spectrum access and cognitive radio (PHYDYAS) and isotropic orthogonal transform algorithm (IOTA) waveforms. First, we present the general concept of the so-called power spectral density (PSD)-based interference tables which are commonly used for multicarrier interference characterization in spectrum sharing context. After highlighting the limits of this approach, we propose a new family of interference tables called `instantaneous interference tables'. The proposed tables give the interference power caused by a given interfering subcarrier on a victim one, not only as a function of the spectral distance separating both subcarriers but also with respect to the timing misalignment between the subcarrier holders. In contrast to the PSD-based interference tables, the accuracy of the proposed tables has been validated through different simulation results. Furthermore, due to the better frequency localization of both PHYDYAS and IOTA waveforms, FBMC technique is demonstrated to be more robust to timing asynchronism compared to OFDM one. Such a result makes FBMC a potential candidate for the physical layer of future cognitive radio systems.

  13. Simple and Flexible Self-Reproducing Structures in Asynchronous Cellular Automata and Their Dynamics

    Science.gov (United States)

    Huang, Xin; Lee, Jia; Yang, Rui-Long; Zhu, Qing-Sheng

    2013-03-01

    Self-reproduction on asynchronous cellular automata (ACAs) has attracted wide attention due to the evident artifacts induced by synchronous updating. Asynchronous updating, which allows cells to undergo transitions independently at random times, might be more compatible with the natural processes occurring at micro-scale, but the dark side of the coin is the increment in the complexity of an ACA in order to accomplish stable self-reproduction. This paper proposes a novel model of self-timed cellular automata (STCAs), a special type of ACAs, where unsheathed loops are able to duplicate themselves reliably in parallel. The removal of sheath cannot only allow various loops with more flexible and compact structures to replicate themselves, but also reduce the number of cell states of the STCA as compared to the previous model adopting sheathed loops [Y. Takada, T. Isokawa, F. Peper and N. Matsui, Physica D227, 26 (2007)]. The lack of sheath, on the other hand, often tends to cause much more complicated interactions among loops, when all of them struggle independently to stretch out their constructing arms at the same time. In particular, such intense collisions may even cause the emergence of a mess of twisted constructing arms in the cellular space. By using a simple and natural method, our self-reproducing loops (SRLs) are able to retract their arms successively, thereby disentangling from the mess successfully.

  14. Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System.

    Science.gov (United States)

    Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

    2016-08-18

    Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems.

  15. Designing a WISHBONE Protocol Network Adapter for an Asynchronous Network-on-Chip

    CERN Document Server

    Soliman, Ahmed H M; El-Bably, M; Keshk, Hesham M A M

    2012-01-01

    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-3E\\textregistered 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 Asynchr...

  16. Design of resolution/power controllable Asynchronous Sigma-Delta Modulator

    Science.gov (United States)

    Deshmukh, Anita Arvind; Deshmukh, Raghvendra B.

    2016-12-01

    This paper presents the design of a Programmable Asynchronous Modulator (PAM) with field control of resolution and power. A novel variable hysteresis Schmitt Trigger (ST) is used for external programmability. Asynchronous Sigma-Delta Modulator (ASDM) implementation with external control voltages is proposed to supervise the resolution and power. This architecture with reduced circuit complexity considerably improves the earlier realizations by eliminating multiple current sources as well switched capacitor circuits and results in power saving up to 87 %. Proposed PAM design demonstrates an improved SNDR of 115 dB, DR of 96 dB, and power consumption below 280 μW. It illustrates Effective Number of Bits (ENOB) to 18.81 and Figure of Merit (FoM) to 0.15 fJ/conversion step. Modulator is implemented in Cadence UMC Hspice 0.18 μm CMOS analog technology. Off-chip PAM control for resolution/power performance has potential applications in battery operated ultra low power applications like IoT; where ADC is one of the major power consuming components. It offers the promise for an efficient performance with power saving.

  17. Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System

    Directory of Open Access Journals (Sweden)

    Youda Liu

    2016-08-01

    Full Text Available Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems.

  18. Visual and Auditory Components in the Perception of Asynchronous Audiovisual Speech.

    Science.gov (United States)

    García-Pérez, Miguel A; Alcalá-Quintana, Rocío

    2015-12-01

    Research on asynchronous audiovisual speech perception manipulates experimental conditions to observe their effects on synchrony judgments. Probabilistic models establish a link between the sensory and decisional processes underlying such judgments and the observed data, via interpretable parameters that allow testing hypotheses and making inferences about how experimental manipulations affect such processes. Two models of this type have recently been proposed, one based on independent channels and the other using a Bayesian approach. Both models are fitted here to a common data set, with a subsequent analysis of the interpretation they provide about how experimental manipulations affected the processes underlying perceived synchrony. The data consist of synchrony judgments as a function of audiovisual offset in a speech stimulus, under four within-subjects manipulations of the quality of the visual component. The Bayesian model could not accommodate asymmetric data, was rejected by goodness-of-fit statistics for 8/16 observers, and was found to be nonidentifiable, which renders uninterpretable parameter estimates. The independent-channels model captured asymmetric data, was rejected for only 1/16 observers, and identified how sensory and decisional processes mediating asynchronous audiovisual speech perception are affected by manipulations that only alter the quality of the visual component of the speech signal.

  19. An Autonomous Wireless Sensor Node With Asynchronous ECG Monitoring in 0.18 μ m CMOS.

    Science.gov (United States)

    Mansano, Andre L; Li, Yongjia; Bagga, Sumit; Serdijn, Wouter A

    2016-06-01

    The design of a 13.56 MHz/402 MHz autonomous wireless sensor node with asynchronous ECG monitoring for near field communication is presented. The sensor node consists of an RF energy harvester (RFEH), a power management unit, an ECG readout, a data encoder and an RF backscattering transmitter. The energy harvester supplies the system with 1.25 V and offers a power conversion efficiency of 19% from a -13 dBm RF source at 13.56 MHz. The power management unit regulates the output voltage of the RFEH to supply the ECG readout with VECG = 0.95 V and the data encoder with VDE = 0.65 V . The ECG readout comprises an analog front-end (low noise amplifier and programmable voltage to current converter) and an asynchronous level crossing ADC with 8 bits resolution. The ADC output is encoded by a pulse generator that drives a backscattering transmitter at 402 MHz. The total power consumption of the sensor node circuitry is 9.7 μ W for a data rate of 90 kb/s and a heart rate of 70 bpm. The chip has been designed in a 0.18 μm CMOS process and shows superior RF input power sensitivity and lower power consumption when compared to previous works.

  20. Fuzzy delay model based fault simulator for crosstalk delay fault test generation in asynchronous sequential circuits

    Indian Academy of Sciences (India)

    S Jayanthy; M C Bhuvaneswari

    2015-02-01

    In this paper, a fuzzy delay model based crosstalk delay fault simulator is proposed. As design trends move towards nanometer technologies, more number of new parameters affects the delay of the component. Fuzzy delay models are ideal for modelling the uncertainty found in the design and manufacturing steps. The fault simulator based on fuzzy delay detects unstable states, oscillations and non-confluence of settling states in asynchronous sequential circuits. The fuzzy delay model based fault simulator is used to validate the test patterns produced by Elitist Non-dominated sorting Genetic Algorithm (ENGA) based test generator, for detecting crosstalk delay faults in asynchronous sequential circuits. The multi-objective genetic algorithm, ENGA targets two objectives of maximizing fault coverage and minimizing number of transitions. Experimental results are tabulated for SIS benchmark circuits for three gate delay models, namely unit delay model, rise/fall delay model and fuzzy delay model. Experimental results indicate that test validation using fuzzy delay model is more accurate than unit delay model and rise/fall delay model.

  1. Significance of microbial asynchronous anabolism to soil carbon dynamics driven by litter inputs

    Science.gov (United States)

    Fan, Zhaosheng; Liang, Chao

    2015-04-01

    Soil organic carbon (SOC) plays an important role in the global carbon cycle. However, it remains largely unknown how plant litter inputs impact magnitude, composition and source configuration of the SOC stocks over long term through microbial catabolism and anabolism, mostly due to uncoupled research on litter decomposition and SOC formation. This limits our ability to predict soil system responses to changes in land-use and climate. Here, we examine how microbes act as a valve controlling carbon sequestrated from plant litters versus released to the atmosphere in natural ecosystems amended with plant litters varying in quantity and quality. We find that litter quality - not quantity - regulates long-term SOC dynamics under different plausible scenarios. Long-term changes in bulk SOC stock occur only when the quality of carbon inputs causes asynchronous change in a microbial physiological trait, defined as ``microbial biosynthesis acceleration'' (MBA). This is the first theoretical demonstration that the response of the SOC stocks to litter inputs is critically determined by the microbial physiology. Our work suggests that total SOC at an equilibrium state may be an intrinsic property of a given ecosystem, which ultimately is controlled by the asynchronous MBA between microbial functional groups.

  2. THE RESEARCH OF GRADATION FUSION ALGORITHM BASED ON MULTISENSOR ASYNCHRONOUS SAMPLING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This letter explores the distributed multisensor dynamic system, which has uniform sampling velocity and asynchronous sampling data for different sensors, and puts forward a new gradation fusion algorithm of multisensor dynamic system. As the total forecasted increment value between the two adjacent moments is the forecasted estimate value of the corresponding state increment in the fusion center, the new algorithm models the state and the forecasted estimate value of every moment. Kalman filter and all measurements arriving sequentially in the fusion period are employed to update the evaluation of target state step by step, on the condition that the system has obtained the target state evaluation that is based on the overall information in the previous fusion period. Accordingly, in the present period, the fusion evaluation of the target state at each sampling point on the basis of the overall information can be obtained. This letter elaborates the form of this new algorithm. Computer simulation demonstrates that this new algorithm owns greater precision in estimating target state than the present asynchronous fusion algorithm calibrated in time does.

  3. A BMI-based occupational therapy assist suit: asynchronous control by SSVEP

    Directory of Open Access Journals (Sweden)

    Takeshi eSakurada

    2013-09-01

    Full Text Available A brain-machine interface (BMI is an interface technology that uses neurophysiological signals from the brain to control external machines. Recent invasive BMI technologies have succeeded in the asynchronous control of robot arms for a useful series of actions, such as reaching and grasping. In this study, we developed non-invasive BMI technologies aiming to make such useful movements using the subject's own hands by preparing a BMI-based occupational therapy assist suit (BOTAS. We prepared a pre-recorded series of useful actionsa grasping-a-ball movement and a carrying-the-ball movementand added asynchronous control using steady-state visual evoked potential (SSVEP signals. A SSVEP signal was used to trigger the grasping-a-ball movement and another SSVEP signal was used to trigger the carrying-the-ball movement. A support vector machine was used to classify EEG signals recorded from the visual cortex (Oz in real time. Untrained, able-bodied participants (n = 12 operated the system successfully. Classification accuracy and time required for SSVEP detection were approximately 88% and 3 s, respectively. We further recruited three patients with upper cervical spinal cord injuries; they also succeeded in operating the system without training. These data suggest that our BOTAS system is potentially useful in terms of rehabilitation of patients with upper limb disabilities.

  4. An asynchronous solver for systems of ODEs linked by a directed tree structure

    Science.gov (United States)

    Small, Scott J.; Jay, Laurent O.; Mantilla, Ricardo; Curtu, Rodica; Cunha, Luciana K.; Fonley, Morgan; Krajewski, Witold F.

    2013-03-01

    This paper documents our development and evaluation of a numerical solver for systems of sparsely linked ordinary differential equations in which the connectivity between equations is determined by a directed tree. These types of systems arise in distributed hydrological models. The numerical solver is based on dense output Runge-Kutta methods that allow for asynchronous integration. A partition of the system is used to distribute the workload among different processes, enabling a parallel implementation that capitalizes on a distributed memory system. Communication between processes is performed asynchronously. We illustrate the solver capabilities by integrating flow transport equations for a ˜17,000 km2 river basin subdivided into 305,000 sub-watersheds that are interconnected by the river network. Numerical experiments for a few models are performed and the runtimes and scalability on our parallel computer are presented. Efficient numerical integrators such as the one demonstrated here bring closer to reality the goal of implementing fully distributed real-time flood forecasting systems supported by physics based hydrological models and high-quality/high-resolution rainfall products.

  5. Asynchronous meiosis in Cucumis hystrix–cucumber synthetic tetraploids resulting in low male fertility

    Directory of Open Access Journals (Sweden)

    Yonghua Han

    2016-08-01

    Full Text Available Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber (Cucumis sativus, 2n = 2x = 14 and its relative C. hystrix (2n = 2x = 24 followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants

  6. Global Exponential Stability for Complex-Valued Recurrent Neural Networks With Asynchronous Time Delays.

    Science.gov (United States)

    Liu, Xiwei; Chen, Tianping

    2016-03-01

    In this paper, we investigate the global exponential stability for complex-valued recurrent neural networks with asynchronous time delays by decomposing complex-valued networks to real and imaginary parts and construct an equivalent real-valued system. The network model is described by a continuous-time equation. There are two main differences of this paper with previous works: 1) time delays can be asynchronous, i.e., delays between different nodes are different, which make our model more general and 2) we prove the exponential convergence directly, while the existence and uniqueness of the equilibrium point is just a direct consequence of the exponential convergence. Using three generalized norms, we present some sufficient conditions for the uniqueness and global exponential stability of the equilibrium point for delayed complex-valued neural networks. These conditions in our results are less restrictive because of our consideration of the excitatory and inhibitory effects between neurons; so previous works of other researchers can be extended. Finally, some numerical simulations are given to demonstrate the correctness of our obtained results.

  7. Asynchronous CDMA Systems with Random Spreading-Part I: Fundamental Limits

    CERN Document Server

    Cottatellucci, Laura; Debbah, Merouane

    2009-01-01

    Spectral efficiency for asynchronous code division multiple access (CDMA) with random spreading is calculated in the large system limit allowing for arbitrary chip waveforms and frequency-flat fading. Signal to interference and noise ratios (SINRs) for suboptimal receivers, such as the linear minimum mean square error (MMSE) detectors, are derived. The approach is general and optionally allows even for statistics obtained by under-sampling the received signal. All performance measures are given as a function of the chip waveform and the delay distribution of the users in the large system limit. It turns out that synchronizing users on a chip level impairs performance for all chip waveforms with bandwidth greater than the Nyquist bandwidth, e.g., positive roll-off factors. For example, with the pulse shaping demanded in the UMTS standard, user synchronization reduces spectral efficiency up to 12% at 10 dB normalized signal-to-noise ratio. The benefits of asynchronism stem from the finding that the excess bandw...

  8. Controllability of time-delayed Boolean multiplex control networks under asynchronous stochastic update.

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-12-17

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) with time delay is studied. Firstly, dynamical model of Boolean multiplex control networks is constructed, which is assumed to be under Harvey' asynchronous update and time delay is introduced both in states and controls. By using of semi-tensor product (STP) approach, the logical dynamics is converted into an equivalent algebraic form by obtaining the control-depending network transition matrices of delayed system. Secondly, a necessary and sufficient condition is proved that only control-depending fixed points of the studied dynamics can be controlled with probability one. Thirdly, respectively for two types of controls, the controllability of dynamical control system is investigated. When initial states and time delay are given, formulae are obtained to show a) the reachable set at time s under specified controls; b) the reachable set at time s under arbitrary controls; c) the reachable probabilities to different destination states. Furthermore, an approach is discussed to find a precise control sequence which can steer dynamical system into a specified target with the maximum reachable probability. Examples are shown to illustrate the feasibility of the proposed scheme.

  9. Controllability of time-delayed Boolean multiplex control networks under asynchronous stochastic update

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan; Liu, Hong

    2014-01-01

    In this article, the controllability of asynchronous Boolean multiplex control networks (ABMCNs) with time delay is studied. Firstly, dynamical model of Boolean multiplex control networks is constructed, which is assumed to be under Harvey' asynchronous update and time delay is introduced both in states and controls. By using of semi-tensor product (STP) approach, the logical dynamics is converted into an equivalent algebraic form by obtaining the control-depending network transition matrices of delayed system. Secondly, a necessary and sufficient condition is proved that only control-depending fixed points of the studied dynamics can be controlled with probability one. Thirdly, respectively for two types of controls, the controllability of dynamical control system is investigated. When initial states and time delay are given, formulae are obtained to show a) the reachable set at time s under specified controls; b) the reachable set at time s under arbitrary controls; c) the reachable probabilities to different destination states. Furthermore, an approach is discussed to find a precise control sequence which can steer dynamical system into a specified target with the maximum reachable probability. Examples are shown to illustrate the feasibility of the proposed scheme. PMID:25516009

  10. An asynchronous pipeline architecture for the low-power AES S-box

    Institute of Scientific and Technical Information of China (English)

    Zeng Yonghong; Zou Xuecheng; Liu Zhenglin

    2008-01-01

    To obtain a low-power and compact implementation of the advanced encryption standard (AES) S-box, an asynchronous pipeline architecture over composite field arithmetic was proposed in this paper. In the presented S-box, some improvements were made as follows. (1) Level-sensitive latches were inserted in data path to block the propagation of the dynamic hazards, which lowered the power of data path circuit. (2) Operations of latches were controlled by latch controllers based on presented asynchronous sequence element: LC-element, which utilized static asymmetric C-element to construct a simple and power-efficient circuit structure. (3) Implementation of the data path circuit was a semi-custom standard-cell circuit on 0.25μm complementary mental oxide semiconductor (CMOS) process; and the full-custom design methodology was adopted in the handshake circuit design. Experimental results show that the resulting circuit achieves nearly 46% improvement with moderate area penalty (11.7%) compared with the related composite field S-box in power performance. The presented S-box circuit can be a hardware intelligent property (IP) embedded in the targeted systems such as wireless sensor networks (WSN), smartcards and radio frequency identification (RFID).

  11. Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System

    Science.gov (United States)

    Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

    2016-01-01

    Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems. PMID:27548171

  12. Verification of Peterson's Algorithm for Leader Election in a Unidirectional Asynchronous Ring Using NuSMV

    CERN Document Server

    Ansari, Amin

    2008-01-01

    The finite intrinsic nature of the most distributed algorithms gives us this ability to use model checking tools for verification of this type of algorithms. In this paper, I attempt to use NuSMV as a model checking tool for verifying necessary properties of Peterson's algorithm for leader election problem in a unidirectional asynchronous ring topology. Peterson's algorithm for an asynchronous ring supposes that each node in the ring has a unique ID and also a queue for dealing with storage problem. By considering that the queue can have any combination of values, a constructed model for a ring with only four nodes will have more than a billion states. Although it seems that model checking is not a feasible approach for this problem, I attempt to use several effective limiting assumptions for hiring formal model checking approach without losing the correct functionality of the Peterson's algorithm. These enforced limiting assumptions target the degree of freedom in the model checking process and significantly...

  13. Learner Perceptions of Asynchronous Oral Computer-mediated Communication: Proficiency and Second Langauge Selves

    Directory of Open Access Journals (Sweden)

    Jesse Gleason

    2012-06-01

    Full Text Available Abstract The present study addresses the perceptions of international teaching assistants regarding the role of language learning tasks using Wimba Voice (WV in aiding the improvement of their second language (L2 oral skills. It specifically examines how this asynchronous computer-mediated communication (CMC technology can foster the development of these learners’ L2 selves. According to Dörnyei (2009, the more clearly learners can envision their future L2 selves, the more motivated they will be to achieve their L2 goals. With increased planning of oral production, access to instructor and peer feedback, and additional opportunities for self-reflection, asynchronous CMC technologies have been found to enable L2 learners to express their thoughts at their own pace and feel more relaxed and confident than in more threatening face-to-face situations (Sun, 2009. The findings suggest that learners have a variety of opinions regarding the role of asynchronous WV tasks in motivating them to develop their L2 oral proficiency. Also, many may prefer oral CMC environments that facilitate interaction and meaning negotiation. Results were inconclusive concerning the effect of WV-based tasks on students' perceptions of their future L2 selves; however, this may have been due to the short time frame in which these activities were employed. Résumé Nous étudions ici les perceptions d’un groupe d’assistants internationaux sur le rôle des tâches d’apprentissage linguistique à l’aide de Wimba Voice (WV. Le projet avait pour but d’améliorer les compétences orales des participants dans leur langue seconde. La présente étude examine en particulier la voie par laquelle cette technologie de la communication asynchrone par ordinateur peut favoriser l’évolution de la langue seconde des apprenants. Selon Dörnyei (2009, plus les apprenants peuvent envisager clairement un futur emploi de leur langue seconde, plus ils seront motivés à atteindre

  14. Engineering Nanoscale Biological Molecular Motors

    OpenAIRE

    Korosec, Chapin; Forde, Nancy R.

    2017-01-01

    Understanding the operation of biological molecular motors, nanoscale machines that transduce electrochemical energy into mechanical work, is enhanced by bottom-up strategies to synthesize novel motors.

  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. 异步电动机定子铁心3D等效热路模型研究%Research of Asychronous Motor Stator Core 3 D Thermal Circuit Model

    Institute of Scientific and Technical Information of China (English)

    田井呈; 邓自清; 王飞宇; 卓克琼; 赵朝会

    2016-01-01

    According to asynchronous motor stator core asymmetry flux density distribution and material heat conduction characteristic,drawed a eight heat resources 3D thermal circuit model for a 7. 5 kW forced air cooling squirrel-cage rotor asynchronous motor, and then use this model calculated stator core temperature distribution based on motor thermal circuit software motor-CAD. The result agreement well with finite element method. This model have a certain reference value for motor thermal analysis and study.%根据异步电动机定子铁心磁密分布不均匀的情况和铁心材料的导热特点,以一台7. 5 kW强迫风冷异步电动机为例,基于3D热路法绘制了定子铁心的8热源等效热路模型,并利用Motor-CAD电机热路计算软件计算了定子铁心的温度分布. 计算结果与采用有限元法相近,证明了该模型的合理性和可行性,对电机温度场的分析和研究具有一定的参考价值.

  17. Research of the multipolar induction traction frequency regulated motor

    Directory of Open Access Journals (Sweden)

    V. Ia. Bespalov

    2014-01-01

    Full Text Available The paper considers the application features of traction induction electric motors in transmissions of vehicles. It shows that one of important stages in their designing is to choose the number of poles. In traction electric drives engines with the raised number of poles without comprehensive assessment of such solution are often applied. The paper investigates dynamic and power characteristics of the multi-polar traction asynchronous engine (TAE designed and made for using in the individual electric drive of heavy-load wheeled cars. The basic functional elements of the model to simulate the electric drive in Matlab environment with the Simulink and SimPower Systems applications in the structure with vector control are described, and the simulation modeling results of its dynamic mechanical characteristics are provided. It is established that because of increased alternating frequency of currents of the multi-polar engine in the range of high speeds there is an excessive decrease in the torque and the requirement for constancy of the target capacity, corresponding to the specified traction characteristic is not fulfilled. It is a consequence of the waveform distortion of engine phase current in the range of high speeds because of incapability of the power source to compensate an increasing EMF of movement as the speed continues to grow.The paper studies the influence of increased current frequencies on the additional losses in the engine. The analysis of electromagnetic field penetration depth in the copper conductor of stator winding at high frequency allowed us to establish a significant skin – effect. The quantitative assessment is given to this phenomenon by results of numerical calculation of electromagnetic field distribution in a stator groove. Significant increase in additional losses in the engine is established, and estimates of flow loss extent because of damping actions of eddy currents in the laminated steel of stator at

  18. Participant Approaches to and Reflections on Learning to Play a 12-Bar Blues in an Asynchronous E-Learning Environment

    Science.gov (United States)

    Seddon, Frederick; Biasutti, Michele

    2009-01-01

    This study investigated the viability of learning to play an improvised 12-bar blues on keyboard with both hands together in an asynchronous e-learning environment. The study also sought to reveal participant approaches to and reflections on this learning experience. Participants were video-taped as they engaged with six "Blues Activities",…

  19. How People Learn in an Asynchronous Online Learning Environment: The Relationships between Graduate Students' Learning Strategies and Learning Satisfaction

    Science.gov (United States)

    Choi, Beomkyu

    2016-01-01

    The purpose of this study was to examine the relationships between learners' learning strategies and learning satisfaction in an asynchronous online learning environment. In an attempt to shed some light on how people learn in an online learning environment, one hundred and sixteen graduate students who were taking online learning courses…

  20. Quantitative monitoring of relative clock wander between signal and sampling sources in asynchronous optical under-sampling system

    Institute of Scientific and Technical Information of China (English)

    Huixing Zhang; Wei Zhao

    2012-01-01

    Optical performance monitoring using asynchronous optical or electrical sampling has gained considerable attention. Relative clock wander between data signal and sampling source is a typical occurrence in such systems. A method for the quantitative monitoring of the relative clock wander in asynchronous optical under-sampling system is presented. With a series of simulations, the clock wanders recovered using this method are in good agreement with the preset clock wanders of different amounts and frequencies for both RZ and NRZ signals. Hence, the reliability and robustness of the method are proven.%Optical performance monitoring using asynchronous optical or electrical sampling has gained considerable attention.Relative clock wander between data signal and sampling source is a typical occurrence in such systems.A method for the quantitative monitoring of the relative clock wander in asynchronous optical under-sampling system is presented.With a series of simulations,the clock wanders recovered using this method are in good agreement with the preset clock wanders of different amounts and frequencies for both RZ and NRZ signals.Hence,the reliability and robustness of the method are proven.

  1. Arguing as an Academic Purpose: The Role of Asynchronous Conferencing in Supporting Argumentative Dialogue in School and University

    Science.gov (United States)

    Coffin, Caroline; Hewings, Ann; North, Sarah

    2012-01-01

    Learning to argue is a key academic purpose for both first and second language students. It has been claimed that computer mediated asynchronous text-based conferencing is a useful medium for developing argumentation skills (Andriessen, Baker, & Suthers, 2003). This paper reports on two research studies which explore this claim. One study focused…

  2. The Effect of Asynchronous/Synchronous Approaches on English Vocabulary Achievement: A Study of Iranian EFL Learners

    Science.gov (United States)

    Khodaparast, Fatemeh; Ghafournia, Narjes

    2015-01-01

    The contribution of computer-assisted instructional programs to language learning process has been the focus of researchers for about two decades. However, the effect of synchronous and asynchronous computer-assisted approaches of language teaching on improving L2 vocabulary has been scarcely investigated. This study explored whether synchronous,…

  3. Developing Students' Metacognitive Awareness in Asynchronous Learning Networks in Comparison to Face-to-Face Discussion Groups

    Science.gov (United States)

    Michalsky, Tova; Zion, Michal; Mevarech, Zemira R.

    2007-01-01

    The main goal of the present study is to investigate empirically the effects of Asynchronic Learning Network (ALN) embedded within metacognitive instruction (META) on two components of metacognitive awareness: Knowledge about Cognition (KC) and Regulation of Cognition (RC). Participants were 202 tenth grade students: 102 students who studied under…

  4. Asynchronous Conferencing with a Twist of Synchronicity: In Search for Tools for Collaborative Moderation in Online Discussions.

    Science.gov (United States)

    Hietala, Pentti; Koivunen, Kimmo

    Carrying out argumentative discussion online has become rather common in higher education. This task is traditionally supported by asynchronous collaboration tools, but this paper suggests that also synchronous supports could be useful. This paper focuses on scaffolding the knowledge construction: the work of two student moderators jointly…

  5. RESEARCH INTO VALVE-ENGINE TRANSDUCERS OF BRUSHLESS SYNCHRONOUS AND ASYNCHRONIZED MACHINES IN A CIRCUIT SIMULATION SYSTEM.

    Directory of Open Access Journals (Sweden)

    A.M. Galynovskiy

    2013-10-01

    Full Text Available Designing features for valve-engine transducers of brushless synchronous and asynchronized machines are described. Global analysis of research results on the transducer models in a MicroCap circuit simulation system is made, recommendations on the simulation system application in both scientific research and educational process given.

  6. Structuring Asynchronous Discussion Groups: Comparing Scripting by Assigning Roles with Regulation by Cross-Age Peer Tutors

    Science.gov (United States)

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

    2010-01-01

    The present study focuses on comparing the impact of role assignment and cross-age peer tutors on students' level of knowledge construction in 15 asynchronous discussion groups of nine students each in a first-year university course (N=135). Content analysis was applied to analyse the level of knowledge construction in students' online postings.…

  7. Effects of Synchronous and Asynchronous Computer-Mediated Communication (CMC) Oral Conversations on English Language Learners' Discourse Functions

    Science.gov (United States)

    AbuSeileek, Ali Farhan; Qatawneh, Khaleel

    2013-01-01

    This study aimed to explore the effects of synchronous and asynchronous computer mediated communication (CMC) oral discussions on question types and strategies used by English as a Foreign Language (EFL) learners. The participants were randomly assigned to two treatment conditions/groups; the first group used synchronous CMC, while the second…

  8. ASYNCHRONICAL MEANS OF FORMING CROSS CULTURAL COMPETENCE OF HIGH SCHOOL STUDENTS (IN THE CASE OF ENGLISH LANGUAGE TEACHING

    Directory of Open Access Journals (Sweden)

    Valeriy G. Apalkov

    2014-01-01

    Full Text Available The article covers the key problems of forming cross cultural competence by means of asynchronic Internet-communication techniques. A concise overview of main studies in using e-mail group in forming cross cultural competence. An algorithm of forming cross cultural competence of high school students is described. 

  9. The Effects of Computer-Mediated Synchronous and Asynchronous Direct Corrective Feedback on Writing: A Case Study

    Science.gov (United States)

    Shintani, Natsuko

    2016-01-01

    This case study investigated the characteristics of computer-mediated synchronous corrective feedback (SCF, provided while students wrote) and asynchronous corrective feedback (ACF, provided after students had finished writing) in an EFL writing task. The task, designed to elicit the use of the hypothetical conditional, was completed by two…

  10. Minimizing asynchronism to improve the performances of anaerobic co-digestion of food waste and corn stover.

    Science.gov (United States)

    Zhou, Qi; Shen, Fei; Yuan, Hairong; Zou, Dexun; Liu, Yanping; Zhu, Baoning; Jaffu, Muhanmad; Chufo, Akiber; Li, Xiujin

    2014-08-01

    To investigate the existence of the asynchronism during the anaerobic co-digestion of different substrates, two typical substrates of food waste and corn stover were anaerobically digested with altering organic loadings (OL). The results indicated that the biodegradability of food waste and corn stover was calculated to be 81.5% and 55.1%, respectively, which was main reason causing the asynchronism in the co-digestion. The asynchronism was minimized by NaOH-pretreatment for corn stover, which could improve the biodegradability by 36.6%. The co-digestion with pretreatment could increase the biomethane yield by 12.2%, 3.2% and 0.6% comparing with the co-digestion without pretreatment at C/N ratios of 20, 25 and 30 at OL of 35 g-VS/L, respectively. The results indicated that the digestibility synchronism of food waste and corn stover was improved through enhancing the accessibility and digestibility of corn stover. The biomethane production could be increased by minimizing the asynchronism of two substrates in co-digestion.

  11. Online-BSEE (Online Bachelor of Science in Electrical Engineering): An Asynchronous Online Electrical Engineering Degree Program with Laboratory

    Science.gov (United States)

    Tang, Wendy; Westgate, Charles; Liu, Pao-Lo; Gouzman, Michael

    2014-01-01

    The Online Bachelor of Science in Electrical Engineering is a collaborative effort among three University Centers at SUNY (State University of New York), namely Stony Brook, Binghamton, and Buffalo. The program delivers the complete electrical engineering curriculum at the bachelor level to students online and asynchronously. Students, however,…

  12. Experimental validation of a truck roll model using asynchronous measurements with low signal-to-noise ratios

    NARCIS (Netherlands)

    Evers, W.-J.; Besselink, I.J.M.; Teerhuis, A.P.; Oomen, T.; Nijmeijer, H.

    2010-01-01

    There is a large body of literature on model validation, but there is no method available that can effectively use asynchronous repeated measurements with low signal-to-noise ratios. The aim of this paper is to present a novel frequency-domain model validation method, which is suitable for this type

  13. Applying reflection and moderation in an asynchronous computer-supported collaborative learning environment in campus-based higher education.

    NARCIS (Netherlands)

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

    2007-01-01

    Working together while accomplishing a task is a characteristic of a powerful learning environment that aims at active knowledge construction. Studies have demonstrated that collaborative learning by using asynchronous communication tools can have advantages over collaboration in a face-to-face sett

  14. Split-phase motor running as capacitor starts motor and as capacitor run motor

    Directory of Open Access Journals (Sweden)

    Yahaya Asizehi ENESI

    2016-07-01

    Full Text Available In this paper, the input parameters of a single phase split-phase induction motor is taken to investigate and to study the output performance characteristics of capacitor start and capacitor run induction motor. The value of these input parameters are used in the design characteristics of capacitor run and capacitor start motor with each motor connected to rated or standard capacitor in series with auxiliary winding or starting winding respectively for the normal operational condition. The magnitude of capacitor that will develop maximum torque in capacitor start motor and capacitor run motor are investigated and determined by simulation. Each of these capacitors is connected to the auxiliary winding of split-phase motor thereby transforming it into capacitor start or capacitor run motor. The starting current and starting torque of the split-phase motor (SPM, capacitor run motor (CRM and capacitor star motor (CSM are compared for their suitability in their operational performance and applications.

  15. Human spinal motor control

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo

    2016-01-01

    interneurons and exert a direct (willful) muscle control with the aid of a context-dependent integration of somatosensory and visual information at cortical level. However, spinal networks also play an important role. Sensory feedback through spinal circuitries is integrated with central motor commands...... and contributes importantly to the muscle activity underlying voluntary movements. Regulation of spinal interneurons is used to switch between motor states such as locomotion (reciprocal innervation) and stance (coactivation pattern). Cortical regulation of presynaptic inhibition of sensory afferents may focus...... the central motor command by opening or closing sensory feedback pathways. In the future, human studies of spinal motor control, in close collaboration with animal studies on the molecular biology of the spinal cord, will continue to document the neural basis for human behavior. Expected final online...

  16. 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.

  17. 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.

  18. Motor Carrier Crash Data -

    Data.gov (United States)

    Department of Transportation — Contains data on large trucks and buses involved in Federally reportable crashes as per Title 49 U.S.C. Part 390.5 (crashes involving a commercial motor vehicle, and...

  19. Knowledge and motor performance.

    Science.gov (United States)

    Kerr, R; Boucher, J L

    1992-06-01

    Traditionally, motor skill acquisition has implied that the performance of a given individual on a particular skill is dependent on the amount of prior practice of that skill. However, concepts such as schema theory, or kinetic formulae, or the strategic allocation of resources imply that, even when practising specific skills, performers gain knowledge about their own motor performance which can be used or applied to related or novel situations. An attempt was made to relate the performance of a complex psychomotor task to differing levels of motor skill expertise or knowledge (athlete and nonathlete). 20 subjects performed (1600 responses) on a novel pursuit or tracking task. Analysis indicated that the athletes performed significantly better. Their main advantage appeared to be more in their ability to control and produce fast, accurate movements than in their decision-making. Accepting Henry and Rogers' 1960 proposition that there is no such thing as a general motor ability or coordination factor does not imply that the only alternative is for all motor skills to be specific. It is argued that the differences in the present study arose from the athletes' greater knowledge (schema, kinetic formulae) related to their understanding of their own motor capabilities.

  20. Shape memory alloy based motor

    Indian Academy of Sciences (India)

    S V Sharma; M M Nayak; N S Dinesh

    2008-10-01

    Design and characterization of a new shape memory alloy wire based Poly Phase Motor has been reported in this paper. The motor can be used either in stepping mode or in servo mode of operation. Each phase of the motor consists of an SMA wire with a spring in series. The principle of operation of the poly phase motor is presented. The motor resembles a stepper motor in its functioning though the actuation principles are different and hence has been characterized similar to a stepper motor. The motor can be actuated in either direction with different phase sequencing methods, which are presented in this work. The motor is modelled and simulated and the results of simulations and experiments are presented. The experimental model of the motor is of dimension 150 mm square, 20 mm thick and uses SMA wire of 0·4 mm diameter and 125 mm of length in each phase.