Single Carrier Frequency Division Multiplexing (SC-FDMA) scheme has been considered to be promising technology for the uplink of the 4G mobile communication systems. The main disadvantage of SC-FDMA is the high envelope fluctuation of signal resulting in a presence of nonlinear distortion in transmitted signal due to the transmitter high power amplifier (HPA). In order to improve the SC-FDMA performance, the 16-ary Amplitude Phase Shift Keying (16-APSK) is proposed as a base-band modulation scheme for SC-FDMA instead of conventional M-QAM. The different types of 16-APSK modulations will be investigated and positions of constellation points will be optimized according to maximizing Mutual Information (MI) criteria. For given value of SNR will be found optimal 16-APSK modulation and it will be proposed adaptive approach of 16-APSK modulation. The performance properties of adaptive approach of 16-APSK and 16-QAM based SC-FDMA transmission scheme will be illustrated using numerical results. The obtained results will show that optimized 16-APSK modulation in SC-FDMA transmitted system provide better performance than 16-QAM SC-FDMA system if the nonlinear model of HPA has to be assumed.

This paper is primarily concerned with analyzing some special properties of the characteristic equation of the linear delay differential equation of the first and odd order. The basic concepts and results keen to the oscillatory nature of solutions, as well as stability analysis are re-investigated using the properties of Lambert W function and compared with existing ones. A brief survey of the function origin and possible applications is presented together with a short behavior analysis.

Quality of Services (QoS) is important for data management in congested networks, especially that one which transfers television streams over internet protocol and can compete with other services available in this network. Network simulators help us to better understand the whole process of QoS. We can better realize purpose of the QoS parameters in simulations, therefore important is to use the proper network simulator. We decide to make short overview of available network simulators used in IPTV QoS research. Article summarize the available computer network simulators, their advantages and disadvantages, mainly their possibility to handle the characteristic network properties like the QoS certainly is.

The shunt active filter is a new solution to improve the power quality. It is able to compensate the current disturbances as well as the reactive power. This paper shows the impact of the neutral current compensation on the two different topologies, according to the obtained results, the configuration with four arms is more preferment than the classical topology which uses the inverter with three arms.

This paper presents a simplified Generalized Pulse Width Modulation (GPWM) algorithm to obtain various continuous and discontinuous PWM algorithms for a four-level inverter topology. The proposed four-level inverter is achieved by feeding the induction motor from both ends by a three-level cascade inverter from one side and by two-level inverter from other side. The proposed inverter configuration is capable to produce an output voltage of two-level, three-level and four-level in entire modulation range. In the proposed inverter topology neutral point fluctuations are absent and neutral clamping diodes are absent. With the application of various discontinuous PWM algorithms to the proposed inverter topology the switching losses are reduced when compared with continuous PWM algorithm. The simulation analyses are carried out in MATLAB/simulink environment and the results are presented.

In the last decade different applications of computer science (data mining, text mining) have been recognised. Presently an automatic question generation is a current research area. The elaborated system generates multi-choice questions from textbooks without using an external semantic database. Main demands made for the implemented automatic question generation system: supporting the Hungarian language, using a free grammar analytic, generating test questions from annotated texts, implementing potential answers from an internal, own developed semantic data base, supporting multi-choice problems, a possibility of implementing electronic and printable test papers. During planning the framework among the applied methods, clustering on the base of distances, a classification algorithm on the base of a neural net, in the case of generating questions and answer alternatives an own developed semantic data base was implemented. To prove the practical applicability of the automated question generating method, Java-language software was developed.

The objective of this article is to point at the analysis of QoS (quality of services) stream for MHP services in unstable IP networks in simulated environment of the Modeller. An overview of QoS, their features and ways of implementations are outlined. The offer of quality of services gets broad extension in IPTV services for communication with the Internet, its availability, broadband, speed. The simulating software Opnet Modeller is used to simulate QoS parameters for transfering real video files in unstable network. 3D video files in standard and high definition are used to compare time delay for each video transfer.

This paper presents the analysis of Static Synchronous Series Compensator (SSSC) and Capacitive Energy storage (CES) based on hydrothermal system under open market scenario employing fuzzy logic controller. The formulation of Load Frequency Control (LFC) problem has been greatly affected due to open transmission access and evolution of more socialized companies for generation, transmission and distribution. The traditional LFC has been modified by taking into account the concept of bilateral contracts. Attempt has also been made to incorporate the concept of SSSC and CES to further improve the performance of the system. A detailed representation of design of Fuzzy Logic Controller (FLC) has been represented and the results have been compared with those of dual mode controller. The results indeed demonstrate the superior working of FLC than that of dual mode controller and the system shows better response with respect to peak time, overshoot and settling time in the presence of FLC.

Although the asynchronous machine is known by its qualities of robustness and low cost of construction, however, it happen that it has an electrical or mechanical fault. This article presented rotoric faults which are treated as part of the detection of broken bars, and the inverter faults (switch fault). This detection technique is based on neural network. The simulation was elaborated on Matlab/Simulink that show results used to assess the performance of the technique presented.