Speech enhancement with an adaptive Wiener filter

This paper proposes an adaptive Wiener filtering method for speech enhancement. This method depends on the adaptation of the filter transfer function from sample to sample based on the speech signal statistics; the local mean and the local variance. It is implemented in the time domain rather than in the frequency domain to accommodate for the time-varying nature of the speech signals. The proposed method is compared to the traditional frequency-domain Wiener filtering, spectral subtraction and wavelet denoising methods using different speech quality metrics. The simulation results reveal the superiority of the proposed Wiener filtering method in the case of Additive White Gaussian Noise (AWGN) as well as colored noise.     

Detection of Abnormal Activities from Various Signals Based on Statistical Analysis

We perceive big data with massive datasets of complex and variegated structures in the modern era. Such attributes formulate hindrances while analyzing and storing the data to generate apt aftermaths. Privacy and security are the colossal perturb in the domain space of extensive data analysis. In this paper, our foremost priority is the computing technologies that focus on big data, IoT (Internet of Things), Cloud Computing, Blockchain, and fog computing. Among these, Cloud Computing follows the role of providing on-demand services to their customers by optimizing the cost factor. AWS, Azure, Google Cloud are the major cloud providers today. Fog computing offers new insights into the extension of cloud computing systems by procuring services to the edges of the network. In collaboration with multiple technologies, the Internet of Things takes this into effect, which solves the labyrinth of dealing with advanced services considering its significance in varied application domains. The Blockchain is a dataset that entertains many applications ranging from the fields of crypto-currency to smart contracts. The prospect of this research paper is to present the critical analysis and review it under the umbrella of existing extensive data systems. In this paper, we attend to critics' reviews and address the existing threats to the security of extensive data systems. Moreover, we scrutinize the security attacks on computing systems based upon Cloud, Blockchain, IoT, and fog. This paper lucidly illustrates the different threat behaviour and their impacts on complementary computational technologies. The authors have mooted a precise analysis of cloud-based technologies and discussed their defense mechanism and the security issues of mobile healthcare.

     

Performance Analysis and Optimization Based on Adaptive Modulation and Chaotic Interleaving for Helicopter-Satellite Communications

Overcoming periodic blockage of the received signal and the carrier frequency fluctuations caused by rotor blades and Doppler shift, respectively, are considered the most challenging issues in helicopter-satellite communication systems. In this study, we propose an automatic frequency control method based on an adaptive modulation scheme. We employ a hybrid modulation not only depending on quadrature phase shift keying, but also based on binary phase shift keying for accurate cancellation of periodic blockage. On the other hand, we apply a chaotic interleaving scheme with a hybrid modulation scheme in order to achieve a better Bit Error Rate (BER) performance in LOS and NLOS environments. Finally, we validate the mathematical analysis of the proposed scheme through simulations. We evaluated the performance of the proposed scheme and performed a comparison with conventional schemes. Our results show that the proposed scheme is significantly capable of reducing the acquisition time and working with various velocities of helicopter blades in addition to providing a better BER performance in shadow fading environments.     

Nuclear-cytoplasmic incompatibility and inefficient development of pig-mouse cytoplasmic hybrid embryos

Inter-species somatic cell nuclear transfer (iSCNT) embryos usually fail to develop to the blastocyst stage and beyond due to incomplete reprogramming of donor cell. We evaluated whether using a karyoplast that would require less extensive reprogramming such as an embryonic blastomere or the meiotic spindle from metaphase II oocytes would provide additional insight into the development of iSCNT embryos. Our results showed that karyoplasts of embryonic or oocyte origin are no different from somatic cells; all iSCNT embryos, irrespective of karyoplast origin, were arrested during early development. We hypothesized that nuclear-cytoplasmic incompatibility could be another reason for failure of embryonic development from iSCNT. We used pig-mouse cytoplasmic hybrids as a model to address nuclear-cytoplasmic incompatibility in iSCNT embryos. Fertilized murine zygotes were reconstructed by fusing with porcine cytoplasts of varying cytoplasmic volumes (1/10 (small) and 1/5 (large) total volume of mouse zygote). The presence of pig cytoplasm significantly reduced the development of mouse zygotes to the blastocyst stage compared with control embryos at 120?h post-human chorionic gondotropin (41 vs 6 vs 94%, P<0.05; 1/10, 1/5, control respectively). While mitochondrial DNA copy numbers remained relatively unchanged, expression of several important genes namely Tfam, Polg, Polg2, Mfn2, Slc2a3 (Glut3), Slc2a1 (Glut1), Bcl2, Hspb1, Pou5f1 (Oct4), Nanog, Cdx2, Gata3, Tcfap2c, mt-Cox1 and mt-Cox2 was significantly reduced in cytoplasmic hybrids compared with control embryos. These results demonstrate that the presence of even a small amount of porcine cytoplasm is detrimental to murine embryo development and suggest that a range of factors are likely to contribute to the failure of inter-species nuclear transfer embryos.     

Synthesis of Some Novel Antioxidant and Anticorrosive Additives for Egyptian Lubricating Oils

Abstract

The starting oxazolone 1 was reacted with p-aminophenol in glacial acetic acid to afford imidazolone 2, which afforded Mannich base 3 via the reaction with piperidine and paraformaldehyde. Moreover, the reaction of 2 with ethylchloroacetate or chloroacetic acid in dry acetone gave the corresponding imidazolones 4 and 5, respectively. Compound 4 reacted with benzylamine or 4-chlorobenzaldehyde to furnish 6 and 7, respectively. On the other hand, oxazolone 1 reacted with hydrazines in glacial acetic acid to afford the 1,2,4-triazines 11–15. Representative compounds of the synthesized products were established and evaluated as antioxidant and corrosion inhibitors for gasoline lube oils.     

Structure of Na2O–CaO–P2O5–SiO2 Glass–Ceramics with Multimodal Porosity

We have investigated the evolution of the structure of nano–macro porous CaO–Na₂O–P₂O₅–SiO₂ bioactive glass–ceramics by Fourier transform infrared (FTIR) and Raman spectroscopies, and X-ray diffraction (XRD). A controlled devitrification, followed by a chemical leaching treatment is used to produce a multimodal distribution of nano/macro pores that are expected to improve cell attachment. Data show that the leaching process removes the sodium- and calcium-containing crystalline phases that are formed during the ceramming heat treatment. The primary Si–O peaks in the infrared spectra blue shift with leaching, indicating that the sample becomes SiO₂ rich. In parallel, the fraction of nonbridging oxygen decreases. These results suggest a restructuring of the glass network far below the glass transition temperature. The stresses from leaching, capillary forces, and subsequent restructuring develop and grow, eventually producing cracks in the sample.     

A Comparison Study Between Pre-Equalization Schemes for Single and Multi Carrier Modulation Systems

In this paper, frequency domain pre-equalization (Pre-FDE) is developed for broadband cyclic prefix-code division multiple access (CP-CDMA) as a single carrier transmission scheme, and for multi carrier-CDMA (MC-CDMA) and orthogonal frequency division multiplexing (OFDM) as multi carrier transmission schemes. A comparison study is held between these schemes and the traditional equalization schemes. Experimental results show that pre-equalization improves significantly the performance of the single and multi carrier communication systems with a very low complexity at the receiver. The comparative study between MIMO pre-equalization for single carrier systems and for multi carrier systems shows that MIMO pre-equalization for single carrier systems outperforms that for multi carrier systems in terms of bit error rate (BER) performance since single carrier transmission has more frequency diversity than multi carrier transmission in the uncoded case.     

Synthesis and applications of some new antioxidant and anticorrosive additives for Egyptian diesel motor oils

Pyrimidine‐5‐carboxylate derivative Ia was utilised as a key intermediate for the synthesis of new pyrimidine derivatives. Thiopyrimidine derivative Ia undergo N‐methylation using methyl iodide afforded III. Methylsulfanyl moiety in II was easily removed when reacted with phenyl hydrazine and thiosemicarbazide afforded pyrimidine derivatives IV and VI, respectively. The reaction on nitrogen atom in Ia using 1,3‐dibromo‐propane, benzoyl chloride, phosphorous oxychloride afforded VIII, IX and X, respectively. The reaction using 1,3‐dibromo‐propane or 1,2‐dibromo‐ethane furnished the formation of the corresponding fused cycles containing sulfur. Representative compounds of the synthesised products were evaluated as antioxidant and corrosion inhibitors for gasoline lube oils. Copyright © 2010 John Wiley & Sons, Ltd.