المستودع الرقمي لـكلية الهندسة

In this paper, a customized Auto-Encoder Complex Valued Convolutional Neural Network (AE-CV-CNN) that has been developed in a prior work is applied to Single Symbol Generalized Spatial Modulation (SS-GSM) scheme with new extracted features. The achieved reductions in the computational complexity at the receiver is at least 63.64% for M-PSK schemes compared to the complexity of Maximum Likelihood (ML) detection algorithm. This Fast detection algorithm is based on a proposed Low Complexity ML (LC-ML) detector that affords a complexity reduction of at least 40.91%. With these proposed algorithms, the complexity is reduced as the spatial constellation size increases. Furthermore, in comparison to other sub optimal detection algorithms, the computational complexity in terms of real valued multiplications of the AE-CV-CNN applied to LC-ML is independent of the spatial spectrum efficiency which means that the total spectrum efficiency increases with larger spatial constellation size at no additional complexity.
Akram A. Marseet , Taissir Y. Elganimi(10-2019)

In this paper, imposing the Hadamard Transform (HDT) on Orthogonal Space-Time Block Codes (OSTBC) schemes using multiple transmit antennas is proposed in order to increase the reliability and improve the error performance of wireless communications. It is referred to as joint Hadamard transform and OSTBC schemes with multiple transmit antennas. However, HDT is used to change the location of constellation points by converting the transmit symbols of OSTBC system, and hence extending the Euclidean distance between transmit symbols for a precise detection. Simulation results demonstrated that increasing the number of transmit antennas in OSTBC systems employing 8-PSK improves the Bit Error Rate (BER) performance as in the case of OSTBC 2×2 scheme where an SNR of about 13.5 dB is required to achieve a BER of 〖10〗^(-6), while only about 7 dB in OSTBC 8×8 scheme is required to obtain the same error probability. It is also demonstrated that imposing the Hadamard criteria on the OSTBC 2×2, 4×4, and 8×8 schemes has showed a performance improvement of about 3 dB, 6 dB and 9 dB, respectively, as compared to the conventional OSTBC systems.
Taissir Y. Elganimi, Marwan B. Elkhoja(4-2019)

Transmit Antenna Selection using Orthogonal Space-Time Block Codes (TAS-OSTBC) aided Millimeter-wave (mmWave) communications is proposed in this paper. The TAS transmitter is characterized by a lower number of Radio Frequency (RF) chains than the number of transmit antennas, hence it is capable of reducing both the energy consumption as well as the transmitter cost. The proposed scheme combines TAS-OSTBC system with Hybrid Analog-Digital Beamforming for 60 GHz mmWave communications and using Hadamard transform. The computer simulation results demonstrate that the TAS-OSTBC scheme with fully digital SVD-based precoding has better Bit Error Rate (BER) performance than that of the conventional TAS system with OSTBC scheme. Furthermore, the error performance is significantly improved by applying Uniform Linear Array (ULA) antennas which improve the system performance as the number of array elements increases due to providing a beamforming gain. It is also found that the BER performance is further improved by applying Hadamard transform with an SNR improvement of about 3dB over the conventional systems without using Hadamard transform.
Taissir Y. Elganimi, Mohammed S. Alshawish, Moustafa M. Abdalla(4-2019)

In this paper, a combination of Space-Time Block Coded Spatial Modulation with Hybrid Analog-Digital Beamforming (STBC-SM-HBF) for Millimeter-wave (mmWave) communications is proposed in order to take advantage of the merits of Spatial Modulation (SM), Space-Time Block Codes (STBC), Analog Beamforming (ABF), and digital precoding techniques while avoiding their drawbacks. This proposed system benefits from the multiplexing gain of SM, from the transmit diversity gain of STBC, and from the Signal-to-Noise Ratio (SNR) gain of the beamformer. The simulation results demonstrate that the Zero Forcing (ZF) and the Minimum Mean Square Error (MMSE) precoded STBC-SM systems have better Bit Error Rate (BER) performance than the precoded SM systems. Moreover, the precoded SM shows a performance degradation compared to STBC-SM system. Furthermore, the BER is significantly improved by employing an array of ABF. In addition, it is demonstrated that a minimum of 2 antenna elements in the proposed scheme of STBC-SM-HBF are required to obtain better BER than that of the conventional SM and STBC-SM systems under the same spectral efficiency of 2 bits/s/Hz.
Taissir Y. Elganimi, Ali A. Elghariani(5-2018)

Joint user selection algorithm and fully digital Geometric Mean Decomposition (GMD)-based precoding scheme is considered in this paper for single Radio Frequency (RF) Space Modulation Techniques (SMTs), namely, Spatial Modulation (SM) and Space Shift Keying (SSK) schemes. The objective is to jointly perform the Frobenius norm-based user selection algorithm and design GMD-based precoded SMTs with single-RF chain in order to reduce the cost and the power consumption in Multiple Input Multiple Output (MIMO) systems, and to avoid the complicated bit-allocation problem of Singular Value Decomposition (SVD)-based precoding technique. Based on these schemes, the GMD-based precoding transmission carried out in the context of a single-user SMTs can readily be extended to the Multi-user (MU) case. Simulation results demonstrate that single-RF SMTs with GMD-based precoding scheme is capable of outperforming SMTs with SVD-based precoding technique. Meanwhile, MU-SMTs with GMD-based precoding scheme provide significant performance gains over the conventional SM- and SSK-MIMO counterparts and single-user SMTs with GMD-based precoding algorithm, which increase the energy efficiency and the reachability using these schemes. Furthermore, better error performance in MU-SMTs with fully digital GMD-based precoding technique is obtained by selecting any number of users. Therefore, MU-SMTs with GMD-based precoding scheme can be effectively used in various 5G wireless networks.
Taissir Y. Elganimi, Feras F. Alfitouri(1-2021)

Most of organizations (both national and international) have struggled with many difficulties during the past decades due to many problems, creating a negative impact on the productivity and utilization levels of many institutions around the globe, and within Libya in particular. This paper presents the current role, relevance, trends and challenges with respect of quality management applications in educational field within Libya as a case study. It outlines an overview of the current state of art to show how in the face of growing global competitiveness quality at the levels of knower, knowing and known elements of educational system using unified field of all the laws of nature, are deriving the benefits of the quality techniques. The paper also investigates the current implementation levels of Total Quality Management (TQM) as a philosophy for improving the quality levels within some academic and training institutions within Libya. A survey methodology has been applied in this research where some findings from interesting case studies are presented to show the benefits of successful TQM implementations originally developed for manufacturing industry. The paper has also pointed to areas where senior managers within the surveyed organizations should take immediate actions to achieve effective and successful TQM implementations, thereby improving their position in this competitive marketplace. arabic 17 English 115
Rajab Abdallah Abdulqader Hokoma(1-2015)

Estimating the service life of Reinforced Concrete (RC) bridge structures located in corrosive marine environments of a great importance to their owners/engineers. Traditionally, bridge owners/engineers relied more on subjective engineering judgment, e.g. visual inspection, in their estimation approach. However, because financial resources are often limited, rational calculation methods of estimation are needed to aid in making reliable and more accurate predictions of the service life of RC structures. This is in order to direct funds to bridges found to be the most critical. Criticality of the structure can be considered either from the Structural Capacity (i.e. Ultimate Limit State) or from Serviceability viewpoint whichever is adopted. This paper considers the service life of the structure only from the Structural Capacity viewpoint. Considering the great variability associated with the parameters involved in the estimation process, the probabilistic approach is most suited. The probabilistic modelling adopted here used Monte Carlo simulation technique to estimate the Reliability (i.e. Probability of Failure) of the structure under consideration. In this paper the authors used their own experimental data for the Correlation Length (CL) for the most important deterioration parameters. The CL is a parameter of the Correlation Function (CF) by which the spatial fluctuation of a certain deterioration parameter is described. The CL data used here were produced by analyzing 45 chloride profiles obtained from a 30 years old RC bridge located in a marine environment. The service life of the structure was predicted in terms of the load carrying capacity of an RC bridge beam girder. The analysis showed that the influence of SV is only evident if the reliability of the structure is governed by the Flexure failure rather than by the Shear failure. arabic 14 English 80
Omran Mohamed Saleh Kenshel(2-2021)

فيما بعد arabic 201 English 0
رجب عبدالله عبدالقادر حكومة, علي الصويعي محمد البوزيدي, عبير المبروك عبدالغفار(6-2017)