Precise Geodetic GPS applications has evolved during the last two decades as the GPS processing and analysis techniques become more robotics and complicated. These progresses cover both the traditional relative positioning methods where more than one receiver are used simultaneously and the single positioning technique. In this study, GPS Precise Point Positioning (PPP) method, that does not require data from any other GPS receiver, was tested and evaluated through various computations environments. The un- differenced dual-frequency pseudo range and carrier phase observations were downloaded from one permanent international GNSS Service (IGS) station and one permanent CORS station. The GPS data were processed using various IGS orbit data in a post-processing manner using the ESA/UPC GNSS-Lab (gLAB) software. The results for various observations scenarios of the PPP solutions were investigated and analyzed. The conclusion and suggested future works are outlined in the research.

Shunt Active Power Filters (APFs) are the up-to-date solution to power quality problems. Harmonic reference detection is the key word for the proper operation of shunt APF. One of the most famous detection control schemes for shunt APFs is the Synchronous Reference Frame (SRF). In this paper, two new modifications of (SRF) detection control scheme are presented. The first modification is done by introducing a new scheme for the dc bus control loop. The second modification is accomplished by implementing the SRF without load current sensors and using only the supply current sensors. These improvements, compared to the conventional (SRF), simplify the control system, minimize the system delay time, improve the APF performance, and reduce the cost of the system. The simulation results, using MATLAB/SIMULINK, demonstrate the viability and simplicity of the modified control scheme, its success in meeting power quality standards limits, and increasing the accuracy of generated reference signal.  

Power dissipation of very large scale integrated circuits (VLSI) has emerged as a significant constraint on the semiconductor industry. For the dynamic power the voltage, capacitance and frequency are the major components of the power dissipation. In this paper, we propose a new power macromodeling technique for the power estimation of complementary metal-oxide- semiconductor (CMOS) inverter using 0.12µm technology. As the dynamic power is directly linked with the load capacitance (CL), it is also a lumped capacitance of all internal parasitic capacitances. In our model, we take an account of the parasitic capacitances with their dependence on channel width and the length. Suitable values of other factors (i.e. threshold voltage VT, gate voltage VGS, drain voltage VDD etc.) are used for the power consumption of the CMOS inverter. The Preliminary results are effective and our macromodel provides the accurate power estimation.

An elastic contact model of a pad/disc system is developed which can give some explanations on self-excited vibration induced during continuous dry friction. Based on this model, it is possible to show that establishement and sustainability of self-excited vibration in disc brake system are linked to the interface properties as well as the physical properties of the disc brake components. It is shown using theoretical and experimental analysis that the regime of self-excited vibrations can be triggered when approaching any of the modified resonant frequencies of either pad or disc system. These frequencies are dependant upon contact stiffness value during self-excitation regime. Experimental investigations have also shown that contact stiffness during sustained self-excitation may increase monotonically upto 35% of its initial value due to continuous wear and sliding. One of the main findings in this work, is that the resonance of any of the system frequencies is linked mainly to the established value of contact stiffness due to wear, load and speed. Also, for each self-excited regime, there is a limiting frequency after which the self-excited regime either sustains at this frequency or change to another regime. Sudden changing of load or speed at this limiting frequency may cause the transition from one regime of self-excitation to another.