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Fixed Point Iteration Chaos Controlled ZCDPLL

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International Journal of Communications, Network and System Sciences 2016年第11期9卷 535-544页

作者： qassim nasir Electrical and Computer Engineering Department University of Sharjah Sharjah UAE

The stable operation of first and second order Zero Crossing Digital Phase Locked Loop (ZCDPLL) is extended by using a Fixed Point Iteration (FPI) method with relaxation. The non-linear components of ZCDPLL such as sampler phase detector and Digital Controlled Oscillator (DCO) lead to unstable and chaotic operation when the filter gains are high. FPI will be used to stabilize the chaotic operation and consequently extend the lock range of the loop. The proposed stabilized loop can work in higher filter gains which are needed for faster signal acquisition.

关键词： Non-Uniform Sampling Digital Phase Locked Loops Zero Crossing DPLL Chaos Control

True Random Bit Generator Using ZCDPLL Based on TMS320C6416

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International Journal of Communications, Network and System Sciences 2009年第4期2卷 258-266页

作者： qassim nasir Department of Electrical and Computer Engineering College of Engineering University of Sharjah Sharjah UAE

A True Random Binary Generator (TRBG) based on a zero crossing digital phase-locked loop (ZCDPLL) is proposed. In order to face the challenges of using the proposed TRBG in cryptography, the proposed TRBG is subjected to the AIS 31 test suite. The ZCDPLL operate as chaotic generator for certain loop filter gains and this has been used to generate TRBs. The generated binary sequences have a good autocorrelation and cross-correlation properties as seen from the simulation results. A prototype of TRBG using ZCDPLL has been developed through Texas Instruments TMS320C6416 DSP development kit. The proposed TRBG successfully passed the AIS 31 test suit.

关键词： True Random Binary Sequence Zero Crossing Digital Phase Locked Loop Spreading Sequences Cryptography TMS320C64x

Predictive FTF Adaptive Algorithm for Mobile Channels Estimation

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International Journal of Communications, Network and System Sciences 2012年第9期5卷 569-578页

作者： qassim nasir Department of Electrical and Computer Engineering University of Sharjah Sharjah UAE

The aim of this research paper is to improve the performance of Fast Transversal Filter (FTF) adaptive algorithm used for mobile channel estimation. A multi-ray Jakes mobile channel model with a Doppler frequency shift is used in the simulation. The channel estimator obtains the sampled channel impulse response (SIR) from the predetermined training sequence. The FTF is a computationally efficient implementation of the recursive least squares (RLS) algorithm of the conventional Kalman filter. A stabilization FTF is used to overcome the problem caused by the accumulation of roundoff errors, and, in addition, degree-one prediction is incorporated into the algorithm (Predictive FTF) to improve the estimation performance and to track changes of the mobile channel. The efficiency of the algorithm is confirmed by simulation results for slow and fast varying mobile channel. The results show about 5 to 15 dB improvement in the Mean Square Error (Deviation) between the estimated taps and the actual ones depending on the speed of channel time variations. Slow and fast vehicular channels with Doppler frequencies 100 Hz and 222 Hz respectively are used in these tests. The predictive FTF (PFTF) algorithm give a better channel SIR estimation performance than the conventional FTF algorithm, and it involves only a small increase in complexity.

关键词： Mobile Channel Estimation Fast Transversal Filter Prediction Adaptive Filtering Algorithms

Adaptive Backoff Algorithm for IEEE 802.11 MAC Protocol

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International Journal of Communications, Network and System Sciences 2009年第4期2卷 300-317页

作者： Maali ALBALT qassim nasir Department of Electrical and Computer Engineering College of Engineering University of Sharjah Sharjah UAE

A Mobile Ad Hoc Network (MANET) is a collection of mobile nodes that can communicate directly over wireless media, without the need for a preconfigured infrastructure. Several approaches have been suggested to improve Quality of Service (QoS) in IEEE 802.11-based MANETs through modifying some of the IEEE 802.11 Medium Access Control (MAC) algorithms, such as the backoff algorithm that is used to control the packets collision aftermath. In this work, an adaptive IEEE 802.11 backoff algorithm to improve QoS is de-veloped and tested in simulations as well as in testbed implementation. While the Binary Exponential Backoff (BEB) algorithm deployed by IEEE 802.11 reacts based on individual packet transmit trials, the new algo-rithm takes the history of successive packet transmit trials into account to provide a better QoS performance. The new algorithm has been tested against the legacy IEEE 802.11 through simulations using QualNet and a Linux-based testbed comprising a number of stations. The performed tests have shown significant im-provements in performance, with up to 33.51% improvement in delay and 7.36% improvement in packet delivery fraction compared to the original IEEE 802.11.

关键词： MANETs Ad-Hoc Networks Quality of Service Backoff Algorithm IEEE 802.11

Linearized Phase Detector Zero Crossing DPLL Performance Evaluation in Faded Mobile Channels

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Circuits and Systems 2011年第3期2卷 139-144页

作者： qassim nasir Saleh Al-Araji 不详

Zero Crossing Digital Phase Locked Loop with Arc Sine block (AS-ZCDPLL) is used to linearize the phase difference detection, and enhance the loop performance. The loop has faster acquisition, less steady state phase error, and wider locking range compared to the conventional ZCDPLL. This work presents a Zero Crossing Digital Phase Locked Loop with Arc Sine block (ZCDPLL-AS). The performance of the loop is analyzed under mobile faded channel conditions. The mobile channel is assumed to be two path fading channel corrupted by additive white Gaussian noise (AWGM). It is shown that for a constant filter gain, the frequency spread has no effect on the steady state phase error variance when the loop is subjected to a phase step. For a frequency step and under the same conditions, the effect on phase error is minimal.

关键词： Non-Uniform Sampling Digital Phase Locked Loops Zero Crossing DPLL Mobile Faded Channels

High Security Nested PWLCM Chaotic Map Bit-Level Permutation Based Image Encryption

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International Journal of Communications, Network and System Sciences 2012年第9期5卷 548-556页

作者： qassim nasir Hadi H. Abdlrudha Department of Electrical and Computer Engineering University of Sharjah Sharjah UAE Petra Private University Faculty of Information Technology Computer Science Department Amman Jordan

Chaotic systems produce pseudo-random sequences with good randomness;therefore, these systems are suitable to efficient image encryption. In this paper, a low complexity image encryption based on Nested Piece Wise Linear Chaotic Map (NPWLCM) is proposed. Bit planes of the grey or color levels are shuffled to increase the encryption complexity. A security analysis of the proposed system is performed and presented. The proposed method combine pixel shuffling, bit shuffling, and diffusion, which is highly disorder the original image. The initial values and the chaos control parameters of NPWLCM maps are derived from external secret key. The cipher image generated by this method is the same size as the original image and is suitable for practical use in the secure transmission of confidential information over the Internet. The experimental results of the proposed method show advantages of low complexity, and high-level security.

关键词： Encryption Chaos Piecewise Chaotic Maps Security

A Deep Learning Approach for Crowd Counting in Highly Congested Scene

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Computers, Materials & Continua 2022年第12期73卷 5825-5844页

作者： Akbar Khan Kushsairy Abdul Kadir Jawad Ali Shah Waleed Albattah Muhammad Saeed Haidawati nasir Megat Norulazmi Megat Mohamed Noor Muhammad Haris Kaka Khel Electrical Section Universiti Kuala Lumpur British Malaysian InstituteSelangor53100Malaysia Department of Electrical Engineering International Islamic UniversityIslamabad44000Pakistan Department of Information Technology College of ComputerQassim UniversityBuraydah51452Saudi Arabia Department of Electrical Engineering National University of Computer and Emerging SciencesIslamabad44000Pakistan Computer Engineering Technology Section Universiti Kuala Lumpur Malaysian Institute of Information TechnologyKuala Lumpur50250Malaysia

With the rapid progress of deep convolutional neural networks,several applications of crowd counting have been proposed and explored in the *** congested scene monitoring,a variety of crowd density estimating approaches has been *** understanding of highly congested scenes for crowd counting during Muslim gatherings of Hajj and Umrah is a challenging task,as a large number of individuals stand nearby and,it is hard for detection techniques to recognize them,as the crowd can vary from low density to high *** deal with such highly congested scenes,we have proposed the Congested Scene Crowd Counting Network(CSCC-Net)using VGG-16 as a core network with its first ten layers due to its strong and robust transfer learning rate.A hole dilated convolutional neural network is used at the back end to widen the relevant field to extract a large range of information from the image without losing its original *** dilated convolution neural network is mainly chosen to expand the kernel size without changing other ***,several loss functions have been applied to strengthen the evaluation accuracy of the ***,the entire experiments have been evaluated using prominent data sets namely,ShanghaiTech parts A,B,UCF_CC_50,and UCF_*** model has achieved remarkable results i.e.,68.0 and 9.0 MAE on ShanghaiTech parts A,B,199.1 MAE on UCF_CC_50,and 99.8 on UCF_QNRF data sets respectively.

关键词： Deep learning congested scene crowd counting fully convolutional neural network dilated convolution

Response surface methodology-based optimization of ultrasound-assisted extraction of β-sitosterol and lupeol from Astragalus atropilosus(roots) and validation by HPTLC method

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Asian Pacific Journal of Tropical Biomedicine 2020年第6期10卷 281-292页

作者： Perwez Alam nasir A.Siddiqui Ali S.Alqahtani Anzarul Haque Omer A.Basudan Saleh I.Alqasoumi M.U.Khan Department of Pharmacognosy College of PharmacyKing Saud UniversityP.O.Box-2457Riyadh-11451Saudi Arabia Department of Pharmacognosy College of PharmacyPrince Sattam bin Abdulaziz UniversityAl-KharjKSA Department of Pharmaceutical Chemistry&Pharmacognosy Unaizah College of PharmacyQassim UniversityAl QassimSaudi Arabia

Objective:To optimize the ultrasonication method for efficient extraction ofβ-sitosterol and lupeol from the roots of Astragalus atropilosus using Box-Behnken design of response surface methodology(RSM),and its validation by high performance thin layer chromatography(HPTLC)***:Ultrasonication method was used to extractβ-sitosterol and lupeol from Astragalus atropilosus(roots).RSM was used to optimize the different extraction parameters *** to solid ratio(10–14 m L/g),temperature(60-80℃)and time(40–60 min)to maximize the yield ofβ-sitosterol and *** quantitative estimation ofβ-sitosterol and lupeol was done in chloroform extract of Astragalus atropilosus by validated HPTLC method on 10 cm×20 cm glass-backed silica gel 60 F254 plate using hexane and ethyl acetate(8:2,v/v)as mobile ***:A quadratic polynomial model was found to be most appropriate with regard to R1(yield of total extraction;R2/%CV=0.9948/0.28),R2(β-sitosterol yield;R2/%CV=0.9923/0.39)and R3(lupeol yield;R2/%CV=0.9942/0.97).The values of adjusted R2/predicted R2/signal to noise ratio for R1,R2,and R3 were 0.9782/0.9551/48.77,0.9904/0.9110/31.33,and 0.9927/0.9401/36.08,respectively,indicating a high degree of correlation and adequate *** linear correlation plot between the predicted and experimental values for R1,R2,and R3 showed high values of R2 ranging from 0.9905-0.9973.β-sitosterol and lupeol in chloroform extract of Astragalus atropilosus were detected at Rf values of 0.22 and 0.34,respectively,atλmax=518 *** optimized ultrasonic extraction produced 8.462%w/w of R1,0.451%w/w of R2 and 0.172%w/w of R3 at 13.5 m L/g liquid to solid ratio,78℃of temperature and 60 min of ***:The experimental findings of RSM optimized extraction and HPTLC analysis can be further applied for the efficient extraction ofβ-sitosterol and lupeol in other species of Astragalus.

关键词： β-sitosterol Lupeol Box-Behnken design Astragalus High performance thin layer chromatography