4G network or Heterogeneous wireless access network will integrate existing wireless access technologies (e.g. 2G, 3G, WiMAX, WLAN, etc…) in order to provide, transparently, end-users with the “best” service through connecting their mobile devices at any time to the best available radio network. In that context, mapping the QoS classes between these different access networks becomes a big challenge. In this paper, we propose a method of mapping between the CoS of UMTS and QoS categories of WiMAX in a tight coupling architecture of Heterogeneous Wireless Access Network (HWAN)

Deep water and deep target environment for Seabed Loging (SBL) has been a challenge, and the better delineation method is needed. This paper describes the curve fitting methods namely smoothing spline and piecewise cubic Hermite interpolating polynomial (PCHIP) to give better delineation. In this work we simulated five geophysical layers namely air (500m), sea water (2000m), over burden (1000m), hydrocarbon (100m) and under burden (1000m) respectively. Target depth was increased gradually by 500m from 1000m to 3000m at constant frequency of 0.125Hz and 1250A current. Due to the weak electromagnetic signal from deep target of SBL we had chosen curve fitting methods to describe hydrocarbon reservoir. The results show that smoothing spline is quantified as compare to the PCHIP due to the existence of various noises in the SBL data. Several numerical results will be presented.

The assumption of constant yield stress in the conventional restart pressure equation neglects the effects of thermal shrinkage and gas voids formation, which in turn resulted in an over-designed production piping systems. This paper presents a study on the effects of flow rates on the formation of voids in gelled waxy crude oil. A flow loop rig simulating offshore waxy crude oil transportation was used to produce a gel. A Magnetic Resonance Imaging (MRI) was used to scan the gelled crude oil over the three planes. Waxy crude oil underwent both dynamic and static cooling to observe the effects of volume flow rates on the voids formed in wax-oil gel. Volume flow rate was found to have different influences on the intra-gel voids in the pipeline. A volume flow rate of 5 L/min resulted in a maximum total voids volume of 6.98% while 20 L/min produced a minimum total voids volume of 5.67% in the entire pipe. Slow flow rates resulted in a larger voids volume near the pipe wall. In contrast, faster flow rates produced insignificantly higher voids volume around pipe core. Generally, slower flow rates favoured the formation of higher total voids volume following sufficient steady time of wax crystal formation, producing larger voids areas in gelled waxy crude oil.

In this paper, we will improve and generalize inequality of Ostrowski type for mappings whose second derivatives belong to L 1 (a, b) . Some well known inequalities can be derived as special cases. In addition, perturbed mid-point inequality and perturbed trapezoid inequality are also obtained. The obtained inequalities have immediate applications in numerical integration where new estimates are obtained for the remainder term of the trapezoid and midpoint formula. Applications to some special means are also investigated.

The unipolar-based devices, silicon schottky (Si) and silicon carbide schottky (SiC) power diodes are investigated for their reverse recovery transient responses and the effects on the switching losses of the FET in the DC-DC converter. Two inductive load chopper circuits are simulated with different test diodes using PSpice software to determine the effectiveness and superiority in each of the devices. All parameter settings are consistent for both converter circuits. The results have shown that the SiC diode has higher energy savings of more than 73.13 % in turn-off switching losses. This eventually corresponds to the reduction of 96.16 % in FET turn-on peak power dissipation of SiC converter. However, there is a minor drawback in drain voltage overshoot of the converter. Some detailed analyses are presented in the paper.