The paper describes a new MLF (Mostly Loaded First) method of HTTP requests scheduling and distribution in a cluster-based Web system. Its application enables keeping the quality of the Web service on the required lev...
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The paper describes a new MLF (Mostly Loaded First) method of HTTP requests scheduling and distribution in a cluster-based Web system. Its application enables keeping the quality of the Web service on the required level and makes the Web service behave in a predictable way, opposite to other Web services offering unpredictable and unreliable services of best-effort type. MLF method helps to keep the page response time within established bounds, so that at a heavy workload, servicing both small and simple or more complex pages, would not exceed the imposed time limit. In the method presented, appropriate mechanisms of HTTP requests scheduling have been applied, as well as a new algorithm of the requests distribution has been proposed. In the paper, the method, the testbed and results obtained, which indicate desirability of further research on the MLF method, are presented.
The refraction and scattering of nonlinear acoustic waves play an important role in the realistic application of medical ultrasound. One cause of these effects is the tissue dependence of the nonlinear medium behavior...
The refraction and scattering of nonlinear acoustic waves play an important role in the realistic application of medical ultrasound. One cause of these effects is the tissue dependence of the nonlinear medium behavior. A method that is able to model those effects is essential for the design of transducers for novel ultrasound modalities. Starting from the Westervelt equation, nonlinear pressure wave fields can be modeled via a contrast source formulation, as has been done with the INCS method. An extension of this method will be presented that can handle inhomogeneities in the coefficient of nonlinearity. The contrast source formulation results in an integral equation, which is solved iteratively using a Neumann scheme. The convergence of this scheme has been investigatedfor relevant media (e.g., blood, brain, and liver). Further, as an example, the method has been applied to compute the 1D nonlinear acoustic wave field in an inhomogeneous medium insonified by a 1 MHz Gaussian pulse propagatingup to 100 mm. The results show that the method is able to predict the propagation and the scattering effects of nonlinear acoustic waves in media with inhomogeneities in the coefficient of nonlinearity. This motivates a similar extension ofthe 3D INCS method.
Experimental data reveal that attenuation is an important phenomenon in medical ultrasound. The phenomenon is of particular importance for applications based on nonlinear propagation, as the higher frequency component...
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This paper provides a review of most commonly used numerical methods for computational electromagnetics. It points main strengths and weakness of given methods.
ISBN:
(纸本)9781424438976
This paper provides a review of most commonly used numerical methods for computational electromagnetics. It points main strengths and weakness of given methods.
The paper presents the idea of using and application of On-Line Analytical Processing (OLAP) systems in monitoring of electrical power engineering devices. Data saved in central repository for historical data are subm...
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ISBN:
(纸本)9781424438976
The paper presents the idea of using and application of On-Line Analytical Processing (OLAP) systems in monitoring of electrical power engineering devices. Data saved in central repository for historical data are submitted through online working analytic systems. At the moment of addition of new data happens process of definition the mutual correlation between the new and already existing data. This leads to the analysis based on OLAP systems. The hereby paper describes the advantages of OLAP systems in aspect of using them in monitoring of electrical power engineering devices.
The article presents the analysis of dynamic states of switched reluctance motors. The analysis was performed for double phase SRM. The Matlab/Simulink environment with PLECS toolbox was used for the calculations. Sim...
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ISBN:
(纸本)9781424438976
The article presents the analysis of dynamic states of switched reluctance motors. The analysis was performed for double phase SRM. The Matlab/Simulink environment with PLECS toolbox was used for the calculations. Simulated transient results of switched reluctance motor were presented in the article. The FEMM software was used for the integral parameters calculations.
The paper presents the range and possibilities of using expert systems at diagnostic measurements of insulation systems of power appliances taken by the acoustic emission (AE) method. Multi-parametric descriptors char...
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ISBN:
(纸本)9781424438976
The paper presents the range and possibilities of using expert systems at diagnostic measurements of insulation systems of power appliances taken by the acoustic emission (AE) method. Multi-parametric descriptors characterizing the AE signals, which can be used in the knowledge base as criteria making the identification of basic partial discharge forms (PDs) possible, have been characterized in detail. The paper shows descriptors describing the AE signals registered in time, frequency, time-frequency domains and statistical data.
The paper presents the performance of the switched reluctance motor. The calculation of the magnetic field and electromagnetic torque were performed using the Femm program, based on the finite element method. The calc...
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ISBN:
(纸本)9781424438976
The paper presents the performance of the switched reluctance motor. The calculation of the magnetic field and electromagnetic torque were performed using the Femm program, based on the finite element method. The calculation results are in good agreement with experimented data obtained on the prototype motor. The presented calculations enables to determine the output electromechanical parameters of the motor already being in the stage of the design.
In the paper measurements of streaming electrification current in the range of low velocities are presented. The measurements were conducted in spinning disk system that uses wireless rotating electrometer. Using this...
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In the paper measurements of streaming electrification current in the range of low velocities are presented. The measurements were conducted in spinning disk system that uses wireless rotating electrometer. Using this system it is possible to measure electrification current in the range of several picoamperes. In proposed configuration the electrometer is installed in measurement object on the disk axle. The digital output is transferred using Bluetooth radio-frequency transceiver. This solution minimizes external disturbances and allows for measurement with standard uncertainty at the level of 30 fA depending on averaging time. The uncertainty slightly depends on spinning velocity. Several dependencies of averaged electrification current on rotational speed were shown. A fresh and C 60 fullerene doped transformer oil were used as an electrification source. It was observed that the electrification current can change its sign for different C 60 concentrations. Doping mineral oil leads to charge reversal in the electric double layer. The system presented in paper extends the range of possible research in the field of electrification on low velocities and can be useful in development of streaming electrification phenomena.
Calculation of the energy losses is a very important problem for the distribution networks exploitation. The paper presents the linear model of the LV distribution network for the energy losses calculation. The compar...
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Calculation of the energy losses is a very important problem for the distribution networks exploitation. The paper presents the linear model of the LV distribution network for the energy losses calculation. The comparison of calculation results for different ways of agregation of energy losses magnitudes are presented in the paper.
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