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New Adaptive Data Transmission Scheme Over HF Radio
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Acceptable Bit Error rate can be maintained by adapting some of the design parameters such as modulation, symbol rate, constellation size, and transmit power according to the channel state.

An estimate of HF propagation effects can be used to design an adaptive data transmission system over HF link. The proposed system combines the well known Automatic Link Establishment (ALE) together with variable rate transmission system. The standard ALE is modified to suite the required goal of selecting the best carrier frequency (channel) for a given transmission. This is based on measuring SINAD (Signal plus Noise plus Distortion to Noise plus Distortion), RSL (Received Signal Level), multipath phase distortion and BER (Bit Error Rate) for each channel in the frequency list. Channel condition evaluation is done by two arrangements. In the first an FFT analysis is used where a pilot signal is transmitted over the channel, while the data itself is used in the second arrangement. Passive channel assessment is used to avoid bad channels hence limiting the frequency pool size to be used in the point to point communication and the time required for  scanning and linking. An exchange of channel information between the transmitting and receiving stations is considered to select the modulation scheme for transmission. Mainly MPSK and MFSK are considered with different levels giving different data rate according to the channel condition. The results of the computer simulation have shown that when transmitting at a fixed channel symbol rate of 1200 symbol/sec, the information rate ranges from 2400 bps using 4FSK up to 3600 bps using 8PSK for SNR ranges from 11dB up to 26dB.

 

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Publication Date
Thu Mar 16 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Synthesis of Some New Heterocyclic Compounds Via Chalcone Derivatives
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  The chalcones 1( a,b) were prepared by the reaction of  2- acetyl benzofuran with two aromatic aldehydes in the presence of alkaline media. These chalcones are used as starting material to obtain the  desired heterocyclic: pyrazolin, isoxazoline, pyrimidinthion, pyrimidinone, cyclohexanone and indazole derivatives. The structure of newly synthesized heterocyclic compounds were established on the basis of  their melting points, elemental analysis(C.H.N), FTIR and 1HMNR (for some of them) spectral data . The synthesized compounds have been screened for their antibacterial activities, they exhibited good antibacterial activity against Escherichia coli (G-) and Staphylococus aureus (G+) . 

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Publication Date
Tue Apr 02 2024
Journal Name
Advances In Systems Science And Applications
A New Face Swap Detection Technique for Digital Images
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Publication Date
Sun Jun 02 2013
Journal Name
Baghdad Science Journal
Synthesis and Characterizationof Some New Phenolic Schiff Bases Derivatives
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Starting from bis (4,4'-diamino phenoxy) ethan(1), a variety of phenolicschiff bases (methylolic, etheric, epoxy) derivatives have been synthesized. All proposed structure were supported by FTIR, 1H-NMR, 13C-NMR Elemental analysis, some derivatives evaluated by thermal analysis (TGA).

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Publication Date
Mon Aug 21 2023
Journal Name
Communications In Mathematical Biology And Neuroscience
New techniques to estimate the solution of autonomous system
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This research aims to solve the nonlinear model formulated in a system of differential equations with an initial value problem (IVP) represented in COVID-19 mathematical epidemiology model as an application using new approach: Approximate Shrunken are proposed to solve such model under investigation, which combines classic numerical method and numerical simulation techniques in an effective statistical form which is shrunken estimation formula. Two numerical simulation methods are used firstly to solve this model: Mean Monte Carlo Runge-Kutta and Mean Latin Hypercube Runge-Kutta Methods. Then two approximate simulation methods are proposed to solve the current study. The results of the proposed approximate shrunken methods and the numerical

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Publication Date
Thu Aug 03 2023
Journal Name
Journal Of Kufa For Mathematics And Computer
Category Theory and New Classes of Semi Bornological Group
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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Synthesis of New Some Imidazole Derivatives Containing ?-Lactam Ring
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In this work 5-methylene-yl - (2-methy –oxazole-4-one) (1H) imidazole (1) were synthesized from the reaction of L-Histidine with acetic anhydride and which converted to the of 5-methylene-yl-(2-methyl 3-amino imidazole-4-one)-1H-imidazole (2) by reaction with hydrazine hydrate. Schiff bases (3-6) were synthesized from the reaction of compound (2) with different aromatic aldehyde. Reaction of compounds (3-6) with chloroacetyl chloride gives azetidinone one derivatives (7-10). These compounds were characterized by FT-IR and some of them with 1H-NMR and 13C-NMR spectroscopy.

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Publication Date
Wed Jan 01 2020
Journal Name
Ieee Access
A New Separable Moments Based on Tchebichef-Krawtchouk Polynomials
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Publication Date
Sun Dec 06 2015
Journal Name
Baghdad Science Journal
New Operational Matrices of Seventh Degree Orthonormal Bernstein Polynomials
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Based on analyzing the properties of Bernstein polynomials, the extended orthonormal Bernstein polynomials, defined on the interval [0, 1] for n=7 is achieved. Another method for computing operational matrices of derivative and integration D_b and R_(n+1)^B respectively is presented. Also the result of the proposed method is compared with true answers to show the convergence and advantages of the new method.

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Publication Date
Fri Jun 23 2023
Journal Name
Al-mustansiriyah Journal Of Science
Image Encryption Using New Non-Linear Stream Cipher Cryptosystem
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In this paper, we designed a new efficient stream cipher cryptosystem that depend on a chaotic map to encrypt (decrypt) different types of digital images. The designed encryption system passed all basic efficiency criteria (like Randomness, MSE, PSNR, Histogram Analysis, and Key Space) that were applied to the key extracted from the random generator as well as to the digital images after completing the encryption process.

Publication Date
Wed Jun 01 2022
Journal Name
Minar International Journal Of Applied Sciences And Technology
NEW RECORD SPECIES OF GENUS ASTRAGALUS L. IN IRAQ
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Astragalus mesogitanus is a new recorded species for Iraqi flora, from Onobrychium genus section, was collected from Erbil district, all morphological features were described in details as well as some micromorphological character as the trichomes and were provided with dimensions and plates, section key was also updated which illustrated the importance of standard (corolla) trichomes in species identification. Keywords: Astragalus, Fabaceae, Iraq, New record, Onobrychium, Trichomes.

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