Preferred Language
Articles
/
UBfc_Y0BVTCNdQwCsCwQ
Hybrid compensation of polarization-multiplexed QPSK optical format for high bit rate networks
...Show More Authors

<span lang="EN-GB">Transmitting the highest capacity throughput over the longest possible distance without any regeneration stage is an important goal of any long-haul optical network system. Accordingly, Polarization-Multiplexed Quadrature Phase-Shift-Keying (PM-QPSK) was introduced lately to achieve high bit-rate with relatively high spectral efficiency. Unfortunately, the required broad bandwidth of PM-QPSK increases the linear and nonlinear impairments in the physical layer of the optical fiber network. Increased attention has been spent to compensate for these impairments in the last years. In this paper, Single Mode Fiber (SMF), single channel, PM-QPSK transceiver was simulated, with a mix of optical and electrical (Digital Signal Processing (DSP)) compensation stages to minimize the impairments. The behaviour of the proposed system was investigated under four conditions: without compensation, with only optical compensator, with only DSP compensator and finally with both compensators. An evidence improvement was noticed in the case of hybrid compensation, where the transmission distance was multiplied from (720 km) to more than (3000 km) at 40 Gb/s.</span>

Scopus Crossref
View Publication
Publication Date
Fri Aug 28 2020
Journal Name
Iraqi Journal Of Science
Electroluminescence of Light- Emitting Organic Semiconductor/ Europium Oxide Nanoparticle Hybrid Junction
...Show More Authors

A hybrid nanoparticles light emitting diode (NPs-LED) was fabricated as layers of ITO/TPD:PMMA/ Eu2O3 / Alq3 / Al, by phase segregation method using spin coating technique. The NPs-LED hybrid device emitted light and consisted of three layers in a definite order placed on the transparent conducting oxide as an ITO substrate; the first layer was made of (N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) benzidine) (TPD) and polymethyl methacrylate (PMMA) polymers combined together. The second layer consisted of Europium (III) oxide (Eu2O3), while the third  layer was Alq3, one of the most frequently-used electron transport layers.

The electroluminescence (EL) of N

... Show More
View Publication Preview PDF
Scopus (9)
Crossref (6)
Scopus Crossref
Publication Date
Sun Feb 10 2019
Journal Name
Iraqi Journal Of Physics
Wear and mechanical prop erties of epoxy/MgO-SiO2 hybrid nanocomposites
...Show More Authors

Preparation of epoxy/MgO and epoxy/SiO2 nanocomposites is
studding. The nano composites were processed by different nano
fillers concentrations (0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.07 and
0.1 wt%). Epoxy resin and nanocomposites containing different
shape nano fillers of (MgO:SiO2 composites), are shear mixing with
ratio 1:1,with different nano hybrid fillers concentrations (0.025,
0.05, 0.1, 0.15, 0.2 and 0.25 wt%) to preparation of epoxy/(MgOSiO2)
hybrid nanocomposites. Experimental tests results indicate that
the composite materials have significantly higher modulus of
elasticity than the matrix material but the hybrid nanocomposites
have lower modulus of elasticity. The wear rate was decreased in
nanoc

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Sep 01 2020
Journal Name
Acta Polytechnica
COMPLEXITY REDUCTION OF CYCLOSTATIONARY SENSING TECHNIQUE USING IMPROVED HYBRID SENSING METHOD
...Show More Authors

In cognitive radio system, the spectrum sensing has a major challenge in needing a sensing method, which has a high detection capability with reduced complexity. In this paper, a low-cost hybrid spectrum sensing method with an optimized detection performance based on energy and cyclostationary detectors is proposed. The method is designed such that at high signal-to-noise ratio SNR values, energy detector is used alone to perform the detection. At low SNR values, cyclostationary detector with reduced complexity may be employed to support the accurate detection. The complexity reduction is done in two ways: through reducing the number of sensing samples used in the autocorrelation process in the time domain and through using the Slid

... Show More
View Publication
Scopus (7)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Economics And Administrative Sciences
Measure the relationship between inflation and the exchange rate in the formulation of Monetary policy in Iraq for the period 1990-2018
...Show More Authors

       Due to the importance of the relationship between the phenomenon of inflation and the exchange rate in the formulation of monetary policy in Iraq, the exchange rate plays a strategic role in limiting the inflation caused by the monetary expansion due to government spending, as a point of a view, the inefficiency of interest to achieve the monetary market balance and stability of the general level of prices as an overall goal of monetary policy in Iraq, the exchange rate has emerged as a brake on inflation in Iraq, as the research found that the monetary authority in the period 2003-2018 provided a methodical development in the formulation of monetary policy towards realizing the effects of inf

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Jan 01 2019
Journal Name
Energy Procedia
Evaluation of the optical properties for thick films of epoxy-diamond paste blend prepared by the casting method
...Show More Authors

View Publication
Scopus (2)
Scopus Clarivate Crossref
Publication Date
Wed May 10 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Study of Annealing and Dopping Effect of Zn on Structural and Optical Properties for CdTe Thin Films
...Show More Authors

In this research thin films of (CdTe) have been prepared as pure and doped by Zn
with different ratios (1,2,3,4,5)% at thickness (400+25)nm with deposition rate (2±0.1)nm,
deposited on glass substrate at R.T. by using thermal evaporation in vacuum . All samples
were annealed at temperature (523,573,623,673)K at 1h.
The structural prop erties of all prepared thin films, doped and undoped have been
studied by using XRD. The analysis reveals that the structures of the films were
polycrystalline and typed cubic with a preferred orientation along (111) plane for the
undoped films with (2,3)% of zinc , and shifting (2ÆŸ) for doped films . The annealing films
at temperature 573 K and Zn:3% show decreasing in

... Show More
View Publication Preview PDF
Publication Date
Tue Jan 01 2013
Journal Name
Thesis
User Authentication Based on Keystroke Dynamics Using Artificial Neural Networks
...Show More Authors

Computer systems and networks are being used in almost every aspect of our daily life, the security threats to computers and networks have increased significantly. Usually, password-based user authentication is used to authenticate the legitimate user. However, this method has many gaps such as password sharing, brute force attack, dictionary attack and guessing. Keystroke dynamics is one of the famous and inexpensive behavioral biometric technologies, which authenticate a user based on the analysis of his/her typing rhythm. In this way, intrusion becomes more difficult because the password as well as the typing speed must match with the correct keystroke patterns. This thesis considers static keystroke dynamics as a transparent layer of t

... Show More
Publication Date
Sun Apr 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Influence Activation Function in Approximate Periodic Functions Using Neural Networks
...Show More Authors

The aim of this paper is to design fast neural networks to approximate periodic functions, that is, design a fully connected networks contains links between all nodes in adjacent layers which can speed up the approximation times, reduce approximation failures, and increase possibility of obtaining the globally optimal approximation. We training suggested network by Levenberg-Marquardt training algorithm then speeding suggested networks by choosing most activation function (transfer function) which having a very fast convergence rate for reasonable size networks.             In all algorithms, the gradient of the performance function (energy function) is used to determine how to

... Show More
View Publication Preview PDF
Publication Date
Sun Nov 26 2017
Journal Name
Journal Of Engineering
Compression Index and Compression Ratio Prediction by Artificial Neural Networks
...Show More Authors

Information about soil consolidation is essential in geotechnical design. Because of the time and expense involved in performing consolidation tests, equations are required to estimate compression index from soil index properties. Although many empirical equations concerning soil properties have been proposed, such equations may not be appropriate for local situations. The aim of this study is to investigate the consolidation and physical properties of the cohesive soil. Artificial Neural Network (ANN) has been adapted in this investigation to predict the compression index and compression ratio using basic index properties. One hundred and ninety five consolidation results for soils tested at different construction sites

... Show More
View Publication Preview PDF
Publication Date
Sat Jul 22 2023
Journal Name
Journal Of Engineering
Multiwavelet based-approach to detect shared congestion in computer networks
...Show More Authors

Internet paths sharing the same congested link can be identified using several shared congestion detection techniques. The new detection technique which is proposed in this paper depends on the previous novel technique (delay correlation with wavelet denoising (DCW) with new denoising method called Discrete Multiwavelet Transform (DMWT) as signal denoising to separate between queuing delay caused by network congestion and delay caused by various other delay variations. The new detection technique provides faster convergence (3 to 5 seconds less than previous novel technique) while using fewer probe packets approximately half numbers than the previous novel technique, so it will reduce the overload on the network caused by probe packets.

... Show More
View Publication Preview PDF
Crossref