Said M. Elhalafawy

An SVD audio watermarking approach using chaotic encrypted images

This paper presents a new approach for audio watermarking using the Singular Value Decomposition (SVD) mathematical technique. The proposed approach can be used for data hiding in the audio signals transmitted over wireless networks and for multi-level security systems as will be stated in the applications section. This approach is based on embedding a chaotic encrypted watermark in the singular values of the audio signal after transforming it into a 2-D format. The selection of the chaotic encryption algorithm for watermark encryption is attributed to its permutation nature, which resists noise, filtering, and compression attacks. After watermark embedding, the audio signal is transformed again into a 1-D format. The transformation between the 1-D and 2-D formats is performed in the well-known lexicographic ordering method used in image processing. The proposed approach can be implemented on the audio signal as a whole or on a segment-by-segment basis. The segment-by-segment implementation allows embedding the same watermark several times in the audio signal, which enhances the detectability of the watermark in the presence of severe attacks. Experimental results show that the proposed audio watermarking approach maintains the high quality of the audio signal and that the watermark extraction and decryption are possible even in the presence of attacks.

Energy Efficient Intra Cluster Transmission in Grid Clustering Protocol for Wireless Sensor Networks

Clustering based routing protocols have a pivotal role in wireless sensor networks (WSN) due to efficient energy consumption of limited power sensor node that is the prime challenge in WSN. Intra-cluster transmission and cluster size have great impact on balancing energy consumption within cluster and network. However, they play minor role in traditional routing protocols. In this paper, authors will offer mathematical analysis to provide judging metric that define energy efficient intra-cluster transmission. This metric is called threshold distance which is exploited in determining optimum cluster size. Based on the optimum cluster size, centralized energy aware grid clustering protocol (CEAG) will be proposed. Mat lab simulator will be utilized for appreciating the proposed protocol. The simulation results manifested that CEAG attains maximum network life tie and throughput in comparison with the existing protocols such as LEACH, K-LEACH, Energy-LEACH, DCHS and MOD-LEACH.

Efficient Transmission of Encrypted Images with OFDM in the Presence of Carrier Frequency Offset

AbstractIn this paper, the impact of carrier frequency offset (CFO) and CFO compensation on the transmission of encrypted images with different orthogonal frequency division multiplexing (OFDM) versions is studied. The investigated OFDM versions are the fast Fourier transform OFDM, the discrete cosine transform OFDM, and the discrete wavelet transform OFDM. A comparison between four encryption algorithms with images transmitted through different OFDM versions is presented. These algorithms are data encryption standard, advanced encryption standard, RC6, and chaotic Baker map. This comparison aims to select the most appropriate version of OFDM, and the most suitable image encryption algorithm for efficient image transmission. In the simulation experiments, the peak signal-to-noise ratio at the receiver is used as an evaluation metric for the decrypted image quality.

UWB integrated microstrip patch antenna with unsymmetrical opposite slots

A new ultra wide band (UWB) probe fed microstrip patch antenna (MPA) with two unsymmetrical opposite slots is proposed. In this paper, two opposite slots with dimensions L1×W1 and L2×W2 were entrenched in radiating edges of patch. The dielectric substrate has dimensions 100×100 mm2 and optimized height of 4mm. A parametric study of slots dimensions, dielectric material type and substrate thickness has been carried out to enhance the impedance bandwidth of the proposed antenna. The antenna performance has been characterized in terms of reflection coefficient (S11) and radiation characteristics. Among different dielectric materials, FR4 epoxy with thickness of 4mm resulted in an impedance bandwidth of 4.8 to 10.6 GHz. The peak gain varies from 4.5 dB to 7.5 dB over the operating frequency range. The antenna was simulated using Ansys HFSS v13 based on Finite element method. This antenna is a suitable candidate for variety of UWB wireless and broadband applications.

Sensitivity of automatic speaker identification to SVD digital audio watermarking

This paper proposes the utilization of SVD digital audio watermarking to increase the security of automatic speaker identification (ASI) systems and presents a study for the effect of watermarking on the ASI system performance. The SVD audio watermarking algorithm can be implemented on audio signals in time domain or in another appropriate transform domain and can be applied to the audio signal as a whole or on a segment-by-segment basis. The speaker recognition system works by generating a database of speaker’s features using the MFCCs and polynomial shape coefficients extracted from each speaker after they are lexicographically ordered into 1-D signals. A matching process is performed for any new speaker to determine if he is belonging to the database or not, using a trained neural network. Experimental results show that the SVD audio watermarking doesn’t degrade the ASI system performance severely. So, it can be used with ASI to increase security. Also, it was shown the segment by segment watermarking in the time domain achieves the highest detectability of the watermark. So, we can say that it is recommended to use SVD segment by segment audio watermarking with ASI systems implementing features extracted from the DCT or the DWT.

Performance of Multiple Antennas Cognitive Relay Networks

Cognitive relay networks (CRNs) combine cognitive radio technique and cooperative relay technology. Cognitive radio offers a tempting solution to increase spectrum usage efficiency by proposing opportunistic usage of frequency bands between primary and secondary users. Many techniques are used to improve the performance of the cognitive relay networks. One of these techniques is using multiple antennas at relay. Another technique is using multiple antennas at the receiver of the system which exist at the energy detector (ED) which is not clarified until now. Adaptive relay protocol (ARP) will be used. Analysis of this system will be made. Moreover different combining techniques will be applied.

DCT assisted speaker identification in the presence of noise and channel degradation

This paper presents a robust speaker identification method from degraded speech signals. This proposed method depends on the Mel-frequency cepstral coefficients (MFCCs) for feature extraction from the degraded speech and its discrete cosine transform (DCT). It is known that the MFCCs based speech recognition methods are not robust enough in the presence of noise and channel degradation. So, the feature extraction from the DCT of the signal will assist in achieving a higher recognition rate. The artificial neural network (ANN) classification technique is used in the proposed method. The comparison between the proposed method and the method using the MFCCs only for feature extraction from noisy speech signals and telephone-like degraded signals shows that the proposed method improves the recognition rate in the presence of noise or degradation.

Design of stacked segmented ultra wide band antenna

In this paper, a novel wide band stacked segment microstrip patch antenna (MPA) with two layered RT/Duroid is proposed. Multi-layered stacked patches are designed with rectangular dimensions, and square slots are entrenched with first patch to excite them. A parametric study of dielectric thickness and stacked center is carried out to enhance the impedance bandwidth of the proposed antenna. The antenna performance has been characterized in terms of reflection coefficient (S11), peak gain and radiation characteristics. Among different cases, thickness and locations of stacked center resulted in an impedance bandwidth of 9.3 to 19 GHz. The peak gain varies of 3dB over the operating frequency range. The antenna was simulated using Ansys HFSS v13 (Finite element method) and CST MWS (Finite Integral Method). This stacked antenna can be a suitable candidate for a variety of modern wireless and broadband applications.