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This study presents the performance of the auto-correlation methods for detecting weak signals, where the signal level is much less than the noise level. Double and triple auto-correlation techniques are used to improve the detection performance compared with the single autocorrelation. Simulation results obtained by MATLAB programs show that the multiple correlation techniques outperform the single correlation in terms of probability of detection and probability of false alarm versus signal to noise ratio SNR.

Due to the current diffusion of reinforced concrete (RC) walls structures and the introduction of new concrete cords, RC walls are an important structural element such as beams, plates and columns. The experimental program included casting and testing of eight two-way thin geopolymer concrete wall panels by using local Iraqi material such as metakaolin and recycled concrete aggregate. The specimen divided in to two groups, group (A) consists of four geopolymer concrete wall panels including recycled concrete aggregate and group (B) consists of four geopolymer concrete walls including ordinary aggregate. In both groups the iron filings percentage volume is varying from 0 to 0.5, 0.75% and 1%. The result showed that the load capacity of the geopolymer concrete wall panel is increased by 17% for geopolymer concrete with recycled concrete aggregate (GCRA) and 4% for geopolymer concrete with natural aggregate (GCNA) by increasing the iron filling ratio to 1%. Also the lateral deflections decrease to 15% for geopolymer concrete with recycled concrete aggregate (GCRA) and 18% for geopolymer concrete with natural aggregate (GCNA) by increasing the iron filings ratio to 1%.

Iris identification plays an important role in many applications like security, banking, access to buildings, and surveillance …. etc. Since the iris part of the eye image can be significantly affected by some factors, such as lighting conditions source, eyelids, eyelashes, pupil, sclera, and shadowing, therefore iris identification research is still wide and rich. The work proposed in this paper operates the iris identification system on the distorted colored images captured under visible light. The proposed idea minimizes the number of iris regions affected by distortion, by dividing the iris region into separable regions. Only the region without distortion part or region with distortion is less probable is used. The paper studies the effect of different color model such as HSV, YIQ, YCbCr, and RGB color models on iris identification. High quality feature extraction is introduced in this paper by using Contourlet Transform (CT). Euclidian Distance (ED) or Neural Network (NN) is used as classifiers. Simulation results show that the proposed method operating on non-distortion iris region outperforms the conventional method operating on the whole iris region for any selected color model and for standard databases (UPOL andUTIRIS) and a suggested one.

Orthogonal frequency division multiplexing (OFDM) is one of the promising technologies to improve the spectral efficiency, enhance system capacity and mitigate inter-symbol interference in the wireless communication system. Adaptive modulation (AM) with OFDM has been suggested as a bandwidth efficient transmission technique in wireless fading environments. In this paper, adaptive modulation techniques is used with OFDM system to improve the throughput performance of the system using four modulation schemes BPSK, QPSK, 8QAM, and 16QAM. Two algorithms to estimate SNR are suggested. The first algorithm is to estimate the SNR for each OFDM symbol in the frame. The second algorithm is to estimate the channel SNR for each subcarrier in the OFDM symbol. The comparison between the results of the two algorithms on the performances of BER and throughput for OFDM system is shown. Furthermore, the effect of various types of channel equalization on performances of system will be determined. The obtained results show that a significant improvements in terms of bit error rate (BER) and throughput can be achieved demonstrating the superiority of the adaptive modulation schemes compared to fixed transmission schemes.