Ahmad Alshamali

Comments on "An efficient coding algorithm for the compression of ECG signals using the wavelet transform"

The author proposed an effective wavelet-based ECG compression algorithm (Rajoub, 2002). The reported extraordinary performance motivated us to explore the findings and to use it in our research activity. During the implementation of the proposed algorithm several important points regarding accuracy, methodology, and coding were found to be improperly substantiated. This paper discusses these findings and provides specific subjective and objective measures that could improve the interpretation of compression results in these research-type problems.

Performance of Spatial Modulation in Correlated and Uncorrelated Nakagami Fading Channel

Spatial Modulation (SM) has been proposed to avoid interchannel interference and the need of exact time synchronization amongst antennas of the Multiple Input Multiple Output (MIMO) transmission system. In this paper, we study the performance of SM in a Nakagami fading environment. Exact integral expressions for calculating the symbol error rate of multilevel Quadrature Amplitude Modulation (M-QAM) of SM in correlated and uncorrelated Nakagami fading channels are derived. The analytical and simulation results match closely over a wide range of SNR values.

Fitting ARMA Models to linear non-Gaussian processes using higher order statistics

This paper addresses the problem of estimating the parameters of a general autoregressive moving average model using higher order statistics (HOS) when only output data are available. The system is driven by an independent and identically distributed (i.i.d) non-Gaussian process. Simulation results are presented which demonstrate the performance of the new method and compare it with a well-known algorithm based on second order and HOS.

Combined coding and wavelet transform for ECG compression

This paper presents a combined wavelet and a modified runlength encoding scheme for the compression of electrocardiogram (ECG) signals. First, a discrete wavelet transform is applied to the ECG signal. The resulting coefficients are classified into significant and insignificant ones based on the required PRD (percent root mean square difference). Second, both coefficients are encoded using a modified run-length coding method. The scheme has been tested using ECG signals obtained from the MIT-BIH Compression Database. A compression of 20:1 (which is equivalent to 150 bit per second) is achieved with PRD less than 10.

8-Oxo-7, 8-dihydro-2′-deoxyguanosine as a biomarker of DNA damage by mobile phone radiation

We examined the effect of exposure to mobile phone 1800 MHz radio frequency radiation (RFR) upon the urinary excretion of 8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG), one major form of oxidative DNA damage, in adult male Sprague-Dawley rats. Twenty-four rats were used in three independent experiments (RFR exposed and control, 12 rats, each). The animals were exposed to RFR for 2 h from Global System for Mobile Communications (GSM) signal generator with whole-body-specific absorption rate of 1.0 W/kg. Urine samples were collected from the rat while housed in a metabolic cage during the exposure period over a 4-h period at 0.5, 1.0, 2.0 and 4.0 h from the beginning of exposure. In the control group, the signal generator was left in the turn-off position. The creatinine-standardized concentrations of 8-oxodG were measured. With the exception of the urine collected in the last half an hour of exposure, significant elevations were noticed in the levels of 8-oxodG in urine samples from rats exposed to RFR when compared to control animals. Significant differences were seen overall across time points of urine collection with a maximum at 1 h after exposure, suggesting repair of the DNA lesions leading to 8-oxodG formation.

GSM Based Remote Ionized Radiation Monitoring System

Nuclear radiation and its effects is a major concern in the world from countries trying to develop the new technology and obsolete reactors that have the potential of leaking dangerous fumes on the health of their entire region. The need for ionized radiation monitoring system to act as an early warning system is essential for the safety of the region. Radiation levels that are not easily noticeable on short term bases might be damaging on long term effects. In this paper, we propose a remote ionized radiation monitoring system using the global system for mobile communication (GSM). Design considerations and implementation of the remote monitoring stations and interconnection to central station via the GSM network are included. The system will continuously measure ionized radiation, store data locally and in case of abnormality (level of radiation becomes greater than the preprogrammed alarm points) alarm messages will be automatically transmitted to the central station.

Combined coding and adaptive thresholding algorithms for ECG compression

This paper proposes a new wavelet-based ECG compression technique. An adaptive thresholding, based on the required signal-to-noise-ratio (SNR) and the concept of energy packing efficiency, is used to classify the wavelet coefficients into significant and insignificant ones. Both coefficients are encoded using an efficient coding algorithm. The proposed technique is tested using several records taken from the MIT-BIH Arrhythmia database. The results show that high compression ratios with SNRs better than 18dB can be achieved.

Spatial modulation: Performance evaluation in Nakagami fading channels

Multiple Input Multiple Output (MIMO) transmission systems have been proposed to increase the spectral efficiency of future wireless communications. However, simultaneous transmission on the same frequency from multiple transmitting antennas causes high interchannel interference (ICI). This significantly increases system complexity with increasing the number of transmitting antennas. Spatial modulation (SM) avoids ICI and the need of accurate time synchronization amongst antennas by making only one antenna active at any instant of time and employing the antenna index as additional source of information. In this paper, the performance of SM in a Nakagami fading environment is studied. Exact integral expressions for calculating the symbol error rate of multilevel Quadrature Amplitude Modulation (M-QAM) of SM in correlated and uncorrelated Nakagami fading channels are derived. The analytical and simulation results match closely over a wide range of SNR values.

Development of accurate expressions for the estimation of delay spread in simulcast networks under Weibull fading

This paper analyzes and evaluates the statistical properties of the rms delay spread (delay spread) in a two-path simulcast environment and same frequency in cell repeater. Each path is subjected to multipath fading characterized by wideband Weibull distribution. A novel, unified, and accurate analytical expressions for the probability density function, the mean, the mean square, and the standard deviation for the delay spread have been derived. The derived expressions are then used to study the implication of the fading and scale parameters on the statistical characteristics of the delay spread. To validate the accuracy of the derived formulas, the analytical results are compared with Monte-Carlo simulation results. Full agreement has been noticed between the simulated and the analytical results over a wide range of received signals levels ratio and different values of the fading parameters.

ECG compression using wavelet transform and particle swarm optimization

A new adaptive thresholding mechanism to determine the significant wavelet coefficients of an electrocardiogram (ECG) signal is proposed. It is based on estimating thresholds for different sub-bands using the concept of energy packing efficiency (EPE). Then thresholds are optimized using the particle swarm optimization (PSO) algorithm to achieve a target compression ratio with minimum distortion. Simulation results on several records taken from the MIT-BIH Arrhythmia database show that the PSO converges exactly to the target compression after four iterations while the cost function achieved its minimum value after six iterations. Compared to previously published schemes, lower distortions are achieved for the same compression ratios.