Carptahian Journal of Electronic and Computer Engineering

4

Authors: P. Molnár, A. Kicsák, J. Végh

The todays computing technology provokes serious debates whether the operating system functions are implemented in the best possible way. The suggestions range from accelerating only certain functions through providing complete real-time operating systems as coprocessors to using simultaneously hardware and software implemented threads in the operating system. The performance gain in such systems depends on many factors, so its quantification is not a simple task at all. In addition to the subtleties of operating systems, the hardware accelerators in modern processors may considerably affect the results of such measurements. The reconfigurable systems offer a platform, where even end users can carry out reliable and accurate measurements. The paper presents a hardware acceleration idea for speeding up a simple OS service, its verification setup and the measurement results.

4

Authors: N. Crișan, L. C. Cremene

A rewriting of the MIMO channel capacity formula is proposed, in order to capture the direct influence of the array matrix (array configuration plus AoA information). The proposed theoretical framework will eventually allow direct comparison between antenna geometries in terms of channel capacity. Simulations indicate that, for small size arrays (up to 8x8), the configuration has a significant influence on the channel capacity, which is no longer the case for larger arrays.

5

Authors: Z. Boudjema, R. Taleb, A. Yahdou, H. Kahal

Traditional vector control structures which include proportional-integral (PI) regulator for the speed of a doubly fed induction motor (DFIM) driven have some disadvantages such as parameter tuning complications, mediocre dynamic performances and reduced robustness. Thus, based on the analysis of the mathematical model of a DFIM supplied by two indirect inverters, this paper addresses a nonlinear control algorithm based on high order sliding mode. The conventional sliding mode control has large chattering on the electromagnetic torque developed by the DFIM. In order to solve this problem, the second order sliding mode technique is used. The simulation results show the effectiveness of the proposed method especially in chattering-free behavior, response to sudden load torque variations and robustness against machine parameters variations.

6

Authors: T. Ivaniga, L. Ovseník, J. Turán

This article is focused SPM (Self-Phase Modulation), whic affects the signal transmision in fully optical communication systems. With the advent of WDM (Wavelength Division Multiplexing) the optical power in optical fiber. For WDM are used weak lasers with 16 or 32 channels. A power of these channels are summed and then we work with the power in fiber about 0.5W which is dangerous for eyes. Therefore for design of the optical network over 10Gbit/s per 1 channel WDM, it is obligation to solve this nonlinear phenomenon. In program package OptSim was created topology 8 and 16- channel DWDM (Dense Wavelenght Division Multiplexing) system according to standard ITU-T (International Telecommunication Union-Telecommunication) G.694.1 with channel spacing of 25GHz, transmission power of 1 and 15 dBm, with transmision speed of 10Gbit/s and two coding types to see the SPM.