Abstract: Lamp tube (TL) lamp with conventional ballast has a low power factor, so it is necessary to increase the power factor by adding a capacitor. Capacitors including non-linear load, so that the addition of the capacitor causing an increase in nonlinear loads. Nonlinear load provides output waveform that is not linear, causing the current waveform and the output voltage is not the same as the input waveform (distorted). The phenomenon of distorted voltages / currents causes the appearance of harmonics. The objective of the research is to show harmonic of currents and voltages before and after the addition of the capacitor. This research conducted was in the laboratory of Electrical Engineering of Vocational School UGM. The research used TL 36W lamps with conventional ballasts and capacitors F 3.2 and 4.5 F. The results show that fluorescent lamp with a conventional ballast has a power factor = 0.514, = 11.1% harmonic current and voltage harmonics 3.7%. The addition of 3.25 F obtained capacitor power factor = 0.876, = 16.3% harmonic current and voltage harmonic = 3.6%. While the addition of 4.5 F obtained capacitor power factor = 0.957, = 21.5% harmonic currents and harmonic voltage = 3.7%

Abstract: Malaysia is a developing country which is having a high level of energy demand. Load demand forecasting is essential that is also in line with increasing demand of electricity. The purpose of the current study is to compare the performance of two time series models in forecasting electricity load demand in Malaysia. Two methods are considered, which are Box-Jenkins Autoregressive Integrated Moving Average (ARIMA) and Double Exponential Smoothing (DES). Using Mean Absolute Percentage Error (MAPE) as the forecasting performance measure, the study concludes that ARIMA is more appropriate model.

Abstract: Sorting is one of most studied problems due to the importance of rearranging data to provide efficient retrieval of required information. The most widely used mechanism for the study of the performance of algorithms is the Rand Access Machine (RAM) model. The model is simple and provides a good tool for the analysis of algorithms. However, computers a have a number of levels of memory hierarchy that necessitates incorporating the idea of hierarchical memory. In this paper, we use the Hierarchical memory with block transfer model which is a RAM but access to a block of locations ending at location x takes x^α, for constant 0 < α < 1, for the last element in the block plus one unit of cost per adjacent items. We provide an asymptotically optimal space and time sorting technique for this problem.

Abstract: This paper presents a control strategy of an induction machine supplied by three level inverters (NPC). The induction machine with the control strategy should provide, at the constraining requests, a response with high performances in electromagnetic torque and flux. This paper aims to demonstrate the contribution of fuzzy logic in the direct torque control (FDTC). This method based on a new fuzzy logic controller to select the output voltage vector by replacing the hysteresis comparators and look-up table in the conventional DTC scheme. By using FDTC not only the torque and flux ripples reduce significantly but also the THD of the phase current decreases since a more sinusoidal current waveform is achieved. Simulation results have verified the feasibility of the proposed control algorithm using Matlab / Simulink.