Mohammed Abo-Zahhad

Bio: Mohammed Abo-Zahhad is an academic researcher from Egypt-Japan University of Science and Technology. The author has contributed to research in topics: Wireless sensor network & Wavelet. The author has an hindex of 24, co-authored 125 publications receiving 1917 citations. Previous affiliations of Mohammed Abo-Zahhad include Assiut University & Jordan University of Science and Technology.

A New Localization Technique for Wireless Sensor Networks Using Social Network Analysis

Abstract: The application of wireless sensor networks is widely spread through the last years as it is well known in many fields and multiple applications. Localization of nodes within wireless sensor networks is one of the important topics in studying and managing these networks. The presented new localization technique combines the received signal strength indicator method which limits the communications between nodes to the range of accessible radiated signal, with a new trend which is social network analysis that deals with relationships between nodes in any network with metrics and layouts. By using mixed metric between degree and closeness, we will maintain the suitable elected seeds that will be anchors for around nodes inside the network. Trilateration calculations will be applied between optimized elected nodes with higher centrality to localize the target nodes.

Dual-band CPW rectenna for low input power energy harvesting applications

Abstract: A dual-frequency band low input power rectenna is proposed in this study. The rectenna is comprised of a co-planar waveguide (CPW) rectifier integrated with a rectangular split ring antenna loaded by a spiral strip line. A single diode series connection topology is used to miniaturise the losses at low input power. A spiral coil in addition to two short circuit stubs are used as a matching network for maximum power transfer between the antenna and the rectifying circuit. The proposed rectenna operates at low input power with relatively high measured RF-DC conversion efficiency up to 74 % at input power of − 6.5 dBm at the first resonant frequency f 1 = 700 MHz and 70 % at − 4.5 dBm at the second operating frequency f 2 = 1.4 GHz with a resistive load of 1.9 k Ω . The measured rectenna sensitivity (the rectenna ability to receive low power with acceptable conversion efficiency) reaches up to − 20 dBm with a conversion efficiency of 47 and 36 % at f 1 and f 2 , respectively, and a DC output voltage of 0.18 V . The measured efficiency is over 50 % from − 18 to − 3.5 dBm and from − 15 to − 1.5 dBm at f 1 and f 2 , respectively.

ECG compression algorithm based on coding and energy compaction of the wavelet coefficients

Abstract: This paper introduces a new effective coding technique for the compression of Electrocardiogram (ECG) signals using the wavelet transform. It is based on generating a binary stream of 1's and 0's that encodes the structure of wavelet coefficients. This binary stream is compressed using a modified run length encoding. The effects of signal length, finite word length representation of the wavelet coefficients and threshold levels selection on the quality of the reconstructed signal that is measured on PRD and compression ratio measures are investigated. The technique is tested for the compression of normal and abnormal ECG signals extracted from MIT-BIH database. The performance parameters of the proposed coding algorithm are measured and a compression ratio of 23.5:1 with a PRD of 1.53% is achieved.

Hybrid Uplink-Time Difference of Arrival and Assisted-GPS Positioning Technique

Abstract: A hybrid positioning system is merely one in which multiple systems are used for positioning purposes. This virtually always, though not necessarily, includes Global Positioning System (GPS) as it is the only global positioning network currently. Combination of mobile network and GPS positioning techniques provide a higher accuracy of mobile location than positions based on a standalone GPS or mobile network based positions. High accuracy of mobile position is mainly essential for emergency, military and many other location based services such as productivity enhancement, entertainment, position-based advertising, navigation, asset management and geographic information access. Assisted GPS, also known as A-GPS or AGPS, enhances the performance of the standard GPS in devices connected to the cellular network. This paper introduces a new hybrid technique for mobile location determination utilizing Universal Mobile Telecommunication System (UMTS) network, Mobile Station (MS) and GPS positioning characteristics. Different positioning techniques are chosen according to positioning parameters. The minimum required number of UMTS base stations, location measurement units and GPS satellites are calculated in this paper. The required number of GPS satellites is reduced from four satellites to three ones while using three dimension positioning and from three satellites to two ones at two dimension positioning. Moreover, MS receiver main functions including both network and GPS received paths to achieve output assisted data are discussed. In this paper many drawbacks such as indoor positioning, receiver high power consumption, delay in first time to fix position, low position accuracy as well as large number of required satellites and base stations are improved.

Utilisation of multi-objective immune deployment algorithm for coverage area maximisation with limit mobility in wireless sensors networks

Abstract: Coverage is one of the most important performance metrics for wireless sensor network (WSN) since it reflects how well a sensor field is monitored. The coverage issue in WSNs depends on many factors, such as the network topology, sensor sensing model and the most important one is the deployment strategy. Random deployment of the sensor nodes can cause coverage holes formulation. This problem is non-deterministic polynomial-time hard problem. So in this study, a new centralised deployment algorithm based on the immune optimisation algorithm is proposed to relocate the mobile nodes after the initial configuration to maximise the coverage area. Moreover, the proposed algorithm limits the moving distance of the mobile nodes to reduce the dissipation energy in mobility and to ensure the connectivity among the sensor nodes. The performance of the proposed algorithm is compared with the previous algorithms using Matlab simulation. Simulation results clear that the proposed algorithm based on binary and probabilistic sensing models improves the network coverage and the redundant covered area with minimum moving consumption energy. Furthermore, the simulation results show that the proposed algorithm also works when obstacles appear in the sensing field.

Wavelet transforms and the ECG: a review.

Abstract: The wavelet transform has emerged over recent years as a powerful time-frequency analysis and signal coding tool favoured for the interrogation of complex nonstationary signals. Its application to biosignal processing has been at the forefront of these developments where it has been found particularly useful in the study of these, often problematic, signals: none more so than the ECG. In this review, the emerging role of the wavelet transform in the interrogation of the ECG is discussed in detail, where both the continuous and the discrete transform are considered in turn.

Coded Communication over Fading Channels

Abstract: In studying the performance of coded communications over memoryless channels (with or without fading), the results are given as upper bounds on the average bit error probability (BEP). In principle, there are three different approaches to arriving at these bounds, all of which employ obtaining the so-called pairwise error probability , or the probability of choosing one symbol sequence over another for a given pair of possible transmitted symbol sequences, followed by a weighted summation over all pairwise events. In this chapter, we will focus on the results obtained from the third approach since these provide the tightest upper bounds on the true performance. The first emphasis will be placed on evaluating the pairwise error probability with and without CSI, following which we shall discuss how the results of these evaluations can be used via the transfer bound approach to evaluate average BEP of coded modulation transmitted over the fading channel.