In this paper a data compression technique using double transforms is proposed. The compression ability of any transform or a combination of transforms is evaluated by the error in the reconstructed data and/or its fast implementation. This investigation concerns the reduction in the computational requirements for data compression without increasing, significantly, the error in reconstruction. The double transform approach is based on the transformation of input data using WHT, rejecting some of the spectral components, converting the spectrum from WHT domain into DCT domain, and then inverse transform using DCT. In the experimental part of this paper, several contours extracted from 2D images, using the FCCE method for contour extraction, ware used. It is shown that the proposed technique reduces the number of multiplication operations, comparing with DCT. In addition, the compression process does not require any multiplications at the transmitting end, thus can be used for real time compression applications.

Experiments were performed to investigate the diffusion ignition process that occurs when hot inert gas (Argon or Nitrogen) is injected into the stoichiometric propane-oxygen mixture at the test section. Detonation wave initiated by spark plug in the driver section in stoichiometric acetylene-oxygen mixture at P = 0.5 bar and room temperature, propagates as incident shock wave in the driven section through inert gas after bursting the diaphragm separating the sections. At the end of driver section the inert gas is heated behind the reflected shock wave and then injected into the test section with the stoichiometric propane-oxygen mixture through the hole of 8 or 11.2 mm in diameter. The results of experiments indicate that ignition occurs when the static enthalpy of injected mass of inert gas exceeds some critical value. The induction time and the adiabatic temperature after reaction of mixed inert gas and Propane-oxygen mixture were determined with the use of CHEMKIN II software [1] for different values of mixing volume ratio.

A definition of thermophysiological parameters of the Specific Anthropomorphic Mannequin (SAM) CAD model material is proposed in this paper to calculate the temperaturerise in the head of cellular handset users. The SAM materials have the electrical and thermal parameters based on the averaged properties of a heterogeneous High-Resolution European Female Head (HR-EFH) with twenty five different tissues. The specific absorption rate (SAR) and the temperature-rise in the SAM because of the exposure to radiation of different handset models, i.e., candy-bar with external antenna and candy-bar with internal antenna, are calculated in the GSM900 and GSM1800 using a FDTD-based platform. The computations were also carried out applying HR-EFH for comparison.

A thorough investigation into the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a clamshell-type cellular handset and a human is presented in this paper. A FDTD-based platform, SEMCAD-X, is used to achieve the simulations, where two semi-realistic handset models of different external-antenna attachment positions (left and rightside) are designed with the most parts configuration and operating at different GSM-frequency standards (GSM-900, GSM-1800/DCS, and UMTS/IMT-2000). Moreover, homogeneous and heterogeneous CAD models are used to simulate the user’s head, whereas, a homogeneous model with three different tissues is designed to simulate the user’s hand-hold. The antenna performance, as well as, the specific absorption rate (SAR) in tissues are both examined for different (42) possible cases, where several antenna/hand positions are considered in simulation.

The impact of human head with different originations on the induced SAR owing to the RF emissions of different cellular handset models is intensively investigated in this paper. Four homogeneous head phantoms with normal (non-pressed) ears are designed and used in simulations for evaluating the electromagnetic (EM) wave interaction between handset antennas and human head at 900 and 1800 MHz with radiated power of 0.25 and 0.125W, respectively. The Difference in heads dimensions due to different origins shows different EM wave interaction with cellular handsets.

Abstract. In many cases, it is impractical to measure the vibrations directly at or close to their source. It is a common practice to measure the vibration at a location far from the source for condition monitoring purposes. The vibration measured in this way inevitably has high distortions from the vibrations due to the effect of the attenuation of signal paths and the interference from other sources. The suppression of the distortions is a key issue for the remote measurements based condition monitoring. In this paper, the influences of transducer locations are investigated on a typical gearbox transmission system for the detection of the faults induced to the gearbox. Several signal processing techniques’ analysis results show that the attenuation and interference cause high influences on the gear transmission signals. However, time synchronous average (TSA) is very effective to detect the local faults induced to the gear system.

We present a model of web-based learning for teaching Visual Programming in Delphi, by adopting individual learning styles. A software system was developed for this purpose where two learning models (namely; 4MAT system and PBL system) are implemented. The goal of this research is to examine the influence of the two selected models on students of different learning styles enrolled in a web-based programming course.

Students were randomly divided into two groups, one for each learning model, and are given access to a website designed specifically for this purpose. Pre and post-tests were carried out.

A controlled evaluation is currently underway to assess the impacts of the system on students programming skills as well as their attitudes surrounding the use of available web facilities.