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Prediction of wireless channel scenarios is fundamental for modern wireless communication systems with diverse propagation conditions. Moreover, the type of data extracted from a wireless communication channel impulse response (CIR) is complex. In recent research, machine learning (ML) techniques have proven their success in classification problems of wireless communication scenarios and provide reasonable results. In this paper, a new enhanced feature selection method is proposed to improve the training model and classification performance of the conventional model. This improvement is achieved based on the concept of regularization in which the selection of the best features is considered before training the model under any propagation environment. The adoption of regularization leads to a high Total Explained Variance (TEV) during the process of kernel Principal Component Analysis (k-PCA). As a consequence, two principal features are used instead of three. The proposed model has high generalization ability since it reduces the features dimensionality (computational complexity) and, generally, enhances the ML classification performance. Experimental simulation is executed to compare the proposed model and the conventional one in terms of accuracy, precision and recall. The accuracy is increased from 97% to 99%, from 96% to 99%, from 89% to 97% and from 90% to 98% for k-nearest neighbor (k-NN), support vector machine (SVM), k-Means and Gaussian mixture model (GMM), respectively. [ABSTRACT FROM AUTHOR]

Increase in the number of infections caused by pathogenic microbes in cancer patients has prompted the searcher to invest in the development of agents having dual anticancer and antimicrobial properties. The present study is concerned with synthesis and screening for anticancer and antimicrobial activity of a series of 5-hydrazinyl-2-(2-(1-(thien-2-yl)ethylidene)hydrazinyl)thiazole derivatives. The structure elucidation of the synthesized hydrazinyl thiazole derivatives was illustrated by spectroscopic and elemental analysis. All the newly synthesized compounds 5a-p were evaluated for in-vitro cytotoxic activity against breast carcinoma (MCF-7 cell line), hepatocellular carcinoma (HePG-2) and colorectal cancer (HCT-116) cell lines using MTT assay method. Compounds 5 g , 5h showed broad spectrum activity against three cancer cell lines with IC 50 ranged from 3.81 to 11.34 µM in compared to the reference drug Roscovitine (IC 50 = 9.32 to 13.82 µM), while compounds 5 l and 5 m were found to be more selective against HePG-2 and HCT-116 cell line (IC 50 = 9.29 and 8.93 µM respectively) and compound 5j was more selective against HePG-2 and MCF-7 cell lines (IC 50 = 6.73 and 10.87 µM respectively). The inhibitory activity of the most promising compounds was tested against the EGFR and ARO enzymes and were further tested for apoptosis and Annexin V/PI staining. The results of enzyme-based tests revealed that the tested compound 5j has a dual inhibitory effect on the EGFR and ARO enzymes with IC 50 = 82.8 and 98.6 nM respectively in compared to the reference drugs Erlotinib and Letrozole (IC 50 = 62.4 and 79 nM respectively). Furthermore, the majority of the tested hydrazinyl thiazole derivatives exhibited significant antimicrobial activity against the used pathogenic microbes species. Compounds 4b , 5h, 5j and 5 m exerted a good antibacterial and antifungal activity against all tested pathogenic microbes. Therefore, it was concluded that compounds 5 h , 5j and 5 m proved to possess dual anticancer and antimicrobial agent and may serves as a useful lead compounds in search for further modification or derivatization to give more potent and selective agents. [ABSTRACT FROM AUTHOR]

Non-contiguous orthogonal frequency division multiplexing (NC-OFDM) is an appropriate transmission technique for cognitive radio (CR) systems. It guarantees an efficient spectrum utilization for high data rate wireless systems. However, NC-OFDM system suffers from two main problems, which are the high peak-to-average power ratio (PAPR) and the high sidelobe level. In this paper, two techniques are proposed to jointly reduce the PAPR and suppress the out-of-band (OOB) radiation caused by the high sidelobe levels. In both of the two proposed techniques, an inverse discrete wavelet packet transform (IDWPT) is used, once with the signal cancellation (SC) for the first proposed technique (IDWPT-SC), and once again with the sub-signal cancellation (Sub-SC) for the second proposed technique (IDWPT-Sub-SC). The use of the IDWPT helps decreasing the fluctuations in the transmitted signal, and hence reduces the PAPR and the OOB radiation. The simulation results show that, the proposed techniques provide better PAPR and sidelobe cancellation performance compared to the other techniques. Moreover, the two proposed techniques also conserve almost the same computational complexity as the other techniques. [ABSTRACT FROM AUTHOR]