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optical pulse propagation in photonic bandgap fiber Bragg grating
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Abstract: In this work we demonstrate and investigate the optical pulse propagation in a photonic band gap fiber Bragg grating (FBG). The light propagates in opposite direction in FBG is explained and discussed by a Coupled Mode Theory (CMT). The photonic band gap (stop band gap) is created by fabricated, a Bragg grating in optical fiber. The results show the pulse spectrum falls entirely within the stop band gap, the entire pulse is reflected by the grating, while when the pulse spectrum is outside the stop band gap the pulses will transmitted through the grating. The group velocity (VG) becomes zero at the edges of the stop band and group velocity dispersion β2 is anomalous on the shorter side of stop band gap whereas β2 for uniform fiber becomes anomalous for wavelengths lower than the zero dispersion.

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Publication Date
Wed Mar 31 2021
Journal Name
لارك
السيد الرئيس والغرانيق
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  نقدم في هذا البحث تحليل لعملين أدبيين من منظور الحركات الطليعية ثبتت آثارها لدى بعض الكتاب العرب و أمريكا اللاتينية في فترة سنوات العشرينات والألفين.  كانت الحياة الخاصة للكاتب ميغيل انخل استورياس تلهمه أنتاج أعمال أدبية، اذ شغل منصب دبلوماسي وحصل على جائزة نوبل غواتيمالاكا. ولد وتوفى في مدينة غواتيملاكا   (1974- 1899)   يوجد تحول واضح في عمله ذات الشهرة السيد الرئيس(1948) الذي يكسر المعتاد، لأجل مست

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Publication Date
Fri Oct 01 2021
Journal Name
International Journal Of Electrical And Computer Engineering (ijece)
Design and implementation of silicon single-photon avalanche photodiode modeling tool for QKD systems
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Single-photon detection concept is the most crucial factor that determines the performance of quantum key distribution (QKD) systems. In this paper, a simulator with time domain visualizers and configurable parameters using continuous time simulation approach is presented for modeling and investigating the performance of single-photon detectors operating in Gieger mode at the wavelength of 830 nm. The widely used C30921S silicon avalanche photodiode was modeled in terms of avalanche pulse, the effect of experiment conditions such as excess voltage, temperature and average photon number on the photon detection efficiency, dark count rate and afterpulse probability. This work shows a general repeatable modeling process for significant perform

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Publication Date
Thu Jul 31 2025
Journal Name
Computers, Materials & Continua
A Secure Audio Encryption Method Using Tent-Controlled Permutation and Logistic Map-Based Key Generation
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The exponential growth of audio data shared over the internet and communication channels has raised significant concerns about the security and privacy of transmitted information. Due to high processing requirements, traditional encryption algorithms demand considerable computational effort for real-time audio encryption. To address these challenges, this paper presents a permutation for secure audio encryption using a combination of Tent and 1D logistic maps. The audio data is first shuffled using Tent map for the random permutation. The high random secret key with a length equal to the size of the audio data is then generated using a 1D logistic map. Finally, the Exclusive OR (XOR) operation is applied between the generated key and the sh

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Publication Date
Tue Feb 01 2022
Journal Name
Baghdad Science Journal
Retina Based Glowworm Swarm Optimization for Random Cryptographic Key Generation
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The biometric-based keys generation represents the utilization of the extracted features from the human anatomical (physiological) traits like a fingerprint, retina, etc. or behavioral traits like a signature. The retina biometric has inherent robustness, therefore, it is capable of generating random keys with a higher security level compared to the other biometric traits. In this paper, an effective system to generate secure, robust and unique random keys based on retina features has been proposed for cryptographic applications. The retina features are extracted by using the algorithm of glowworm swarm optimization (GSO) that provides promising results through the experiments using the standard retina databases. Additionally, in order t

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Publication Date
Sun Sep 04 2011
Journal Name
Baghdad Science Journal
A Mathematical Approach for Computing the Linear Equivalence of a Periodic Key-Stream Sequence Using Fourier Transform
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A mathematical method with a new algorithm with the aid of Matlab language is proposed to compute the linear equivalence (or the recursion length) of the pseudo-random key-stream periodic sequences using Fourier transform. The proposed method enables the computation of the linear equivalence to determine the degree of the complexity of any binary or real periodic sequences produced from linear or nonlinear key-stream generators. The procedure can be used with comparatively greater computational ease and efficiency. The results of this algorithm are compared with Berlekamp-Massey (BM) method and good results are obtained where the results of the Fourier transform are more accurate than those of (BM) method for computing the linear equivalenc

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Publication Date
Tue Apr 11 2023
Journal Name
College Of Islamic Sciences
Collision in the dispute between the two imams Shafi’i and Abu Hanifa by Sheikh Mansour bin Muhammad bin Abd al-Jabbar al-Marwazi al-Samani Abi al-Muzaffar (d. 498 AH) from the issue (If one of the Muslim spouses apostatized and one of the infidel spouses
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The science of jurisprudence is one of the legal sciences that scholars have been interested in since the first centuries of Islam, and they wrote many books about it, and the science of manuscripts is considered one of the scientific achievements in which many scholars emerged, including Imam Al-Samaani, so I chose this manuscript related to Istism to clarify its concept and meaning for all people, The student (Ali Ahmed Abdel-Aziz Sheikh Hamad) preceded me in the investigation of part of the book, and it was facilitated for me, by the grace of God Almighty, to investigate the issue (if one of the Muslim spouses apostatized and one of the infidel spouses converted to Islam until the end of the issue of if the two spouses were taken capt

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Publication Date
Tue Jun 01 2021
Journal Name
Journal Of The College Of Languages (jcl)
A comparative reading of the social and political satire in the works of Abu al-Fadl Zrui Nasrabad and Ahmad Rajab (The tadhk: خوانش تطبیقی طنز اجتماعی – سیاسی در آثار ابوالفضل زرویی نصرآباد و احمد رجب(مورد مطالعه: تذکرة المقامات زرویی و نصف كلمة احمد رجب)
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           Satire is genre of the literary arts that has always been the source of human interest. Because  it is difficult to accept direct criticism, Satire appears as a literary tool in which vices, follies, abuses and shortcomings are held up to ridicule, with the intent of shaming individuals, corporations, government, or society itself into improvement. A satirical critic usually employs irony to attain this goal. Although satire is usually meant to be humorous, its greater purpose is often profitable social criticism, using wit to draw at

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Publication Date
Mon Jan 01 2024
Journal Name
Baghdad Science Journal
Proposed Hybrid Cryptosystems Based on Modifications of Playfair Cipher and RSA Cryptosystem
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Cipher security is becoming an important step when transmitting important information through networks. The algorithms of cryptography play major roles in providing security and avoiding hacker attacks. In this work two hybrid cryptosystems have been proposed, that combine a modification of the symmetric cryptosystem Playfair cipher called the modified Playfair cipher and two modifications of the asymmetric cryptosystem RSA called the square of RSA technique and the square RSA with Chinese remainder theorem technique. The proposed hybrid cryptosystems have two layers of encryption and decryption. In the first layer the plaintext is encrypted using modified Playfair to get the cipher text, this cipher text will be encrypted using squared

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Publication Date
Tue Mar 30 2021
Journal Name
College Of Islamic Sciences
Abu Izac Al-Zauali (d.616 A.H) His life and what Existed of his poetry
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   The aim of this research is to identify the Andalusia  poet  Abu Izac Al-Zauali , whose  most of his poetry and biography had been lost, as well as many Andalusia  poets. So this research is hoped to be the first step to shed the light on the poet’s life and poetry  and to document his poetry as other  writers do. It is also hoped that this research would pave the way , God willing , to the steps of finding more references about this poet .

Key Words: (Al-Zauali, Cordoba, Al-Ruaini choices, Andalusia Poetry , Almuahdi Era).

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Publication Date
Wed Sep 01 2021
Journal Name
Baghdad Science Journal
An Efficient Image Encryption Using a Dynamic, Nonlinear and Secret Diffusion Scheme
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The growing use of tele

This paper presents a new secret diffusion scheme called Round Key Permutation (RKP) based on the nonlinear, dynamic and pseudorandom permutation for encrypting images by block, since images are considered particular data because of their size and their information, which are two-dimensional nature and characterized by high redundancy and strong correlation. Firstly, the permutation table is calculated according to the master key and sub-keys. Secondly, scrambling pixels for each block to be encrypted will be done according the permutation table. Thereafter the AES encryption algorithm is used in the proposed cryptosystem by replacing the linear permutation of ShiftRows step with the nonlinear and secret pe

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