Published Journal in the Journal of Circuits Syst. Signal Process

NISC Center would like to congratulate Dr. Ahmed G. Radwan for his accepted Journal Papers in 2016, Which is published in the Journal of Circuits Syst. Signal Process


  1. Costas Psychalinos, Ahmed S. Elwakil, Ahmed G. Radwan, Karabi Biswas, “Guest Editorial: Fractional-Order Circuits and Systems: Theory, Design, and Applications,” Circuits Syst. Signal Process, 35, 1807-1813, 2016. DOI 10.1007/s00034-016-0285-8

Nowadays, there is a significant research interest in the area of fractional-order circuits. This originates from the fact that they find applications in biochemistry, medicine, electrical engineering, and many other fields. For example, the modeling of viscoelasticity as well as of biological cells and tissues has been performed through the utilization of fractional-order calculus. This special issue is focused on the theory, design, and applications of fractional-order circuits and systems, with the purpose of offering to the circuits and systems community the opportunity to explore recent advances in fractional-order circuits and systems theory and design as well as of their applications.

Published Journal in the Journal of Circuits Syst. Signal Process

NISC Center would like to congratulate Dr. Ahmed G. Radwan, Lobna A. Said and Ahmed H. Madian for their accepted Journal Papers in 2016, Which is published in the Journal of Circuits Syst. Signal Process


  1. Lobna A. Said, Samar M. Ismail, Ahmed G. Radwan, Ahmed H. Madian, Mohamed F. Abu El-Yazeed, Ahmed M. Soliman “On The Optimization of Fractional Order Low-Pass Filters,” Circuits Syst. Signal Process, 35, 2017–2039, 2016. DOI 10.1007/s00034-016-0258-y

This paper presents three different optimization cases for normalized fractional order low-pass filters (LPFs) with numerical, circuit and experimental results. A multi-objective optimization technique is used for controlling some filter specifications, which are the transition bandwidth, the stop band frequency gain and the maximum allowable peak in the filter pass band. The extra degree of freedom provided by the fractional order parameter allows the full manipulation of the filter specifications to obtain the desired response required by any application. The proposed mathematical model is further applied to a case study of a practical second- generation current conveyor (CCII)-based fractional low-pass filter. Circuit simulations are performed for two different fractional order filters, with orders 1.6 and 3.6, with cutoff frequencies 200 and 500 Hz, respectively. Experimental results are also presented for LPF of 4.46 kHz cutoff frequency using a fabricated fractional capacitor of order 0.8, proving the validity of the proposed design approach.

Published Journal in the Microelectronics Journal

NISC Center would like to congratulate Dr. Ahmed G. Radwan for his accepted Journal Papers in 2016, Which is published in the Journal of Microelectronics


  1. Mourad S. Semary, Hany L. Abdel Malek, Hany N. Hassan, Ahmed G. Radwan, “An optimal linear system approximation of nonlinear fractional-order memristor–capacitor charging circuit,” Microelectronics J., 51, 58 – 66, 2016.

The analysis of nonlinear fractional-order circuits is a challenging problem. This is due to the lack of nonlinear circuit theorems and designs particularly in the presence of memristive elements. The response of a series connection of a simple resistor with fractional order capacitor and its analytical formulation in both charging and discharging phases is considered. The numerical simulation of fractional order HP memristor in series with a fractional order capacitor is also discussed. It is a demonstration of a simple nonlinear fractional-order memristive circuit in both charging and discharging cases. Furthermore, this paper introduces an approach to approximate nonlinear fractional-order memrisitve circuits by linear circuits using a minimax optimization technique. Hence, the new circuit can be analyzed using the conventional linear circuit theorems. The charging and discharging of a series fractional-order memristor with a fractional-order capacitor are discussed numerically. The effect of fractional-order parameters and memristor polarity are also investigated. Using a suitable optimization technique, an accurate approximation by a circuit that include a resistor and a fractional-capacitor is obtained for both charging and discharging cases. A great matching was observed between the frequency responses of the fractional-order nonlinear low pass filter based on fractional-order memristor and fractional-order capacitor and that of the optimized linear fractional order case. Similar matching is observed for the nonlinear and optimized cases when a periodic triangular waveform is applied using Fourier series expansion.

Published Journal in the Journal of Circuits Systems, and Signal Processing

NISC Center would like to congratulate Dr. Lobna A. Siad, Ahmed H. Madian and Ahmed G. Radwan for their accepted Journal Papers in 2016, Which is published in the Journal of Circuits Systems, and Signal Processing


 

  1. Lobna A. Said, Ahmed G. Radwan, Ahmed H. Madian, Ahmed M. Soliman, “Fractional Order Oscillator Design Based on Two-Port Network,” Circuits Systems, and Signal Processing, in press, 2016. DOI: 10.1007/s00034-015-0200-8.

In this paper, a general analysis of the generation for all possible fractional order oscillators based on two-port network is presented. Three different two-port network classifications are used with three external single impedances, where two are fractional order capacitors and a resistor. Three possible impedance combinations for each classification are investigated, which give nine possible oscillators. The characteristic equation, oscillation frequency and condition for each presented topology are derived in terms of the transmission matrix elements and the fractional order parameters α and β. Mapping between some cases is also illustrated based on similarity in the characteristic equation. The use of fractional order elements α and β adds extra degrees of freedom, which increases the design flexibility and frequency band, and provides extra constraints on the phase difference. Study of four different active elements, such as voltage-controlled current source, gyrator, op-amp-based network, and second-generation current-conveyor-based network, serve as a two-port network is presented. The general analytical formulas of the oscillation frequency and condition as well as the phase difference between the two oscillatory outputs are derived and summarized in tables for each designed oscillator network. A comparison between fractional order oscillators with their integer order counterparts is also illustrated where some designs cannot work in the integer case. Numerical Spice simulations and experimental results are given to validate the presented analysis.

Dr. Abo-bakr Youssef Visit

bakr_0

Nisc center is pleased with Dr. Abo-bakr Youssef Visit. Dr. Abo-bakr met with faculty, researchers and students to address ideas in biomedical field. Dr. Abo-bakr Started Working at Gafat Enterprises.,LLC in 2015.  Dr. Abo-bakr is biomedical engineering professor.

 

Published Journal in the Journal of Water Science & Technology

NISC Center would like to congratulate Dr. Ahmed G. Radwan for his accepted Journal Papers in 2016, Which is published in the Journal of Water Science & Technology


 

  1. Mostafa M. El-Seddik, Mona M. Galal, G. Radwan, Hisham S. Abdel-Halim, “Modified kinetic-hydraulic UASB reactor model for treatment of wastewater containing biodegradable organic substrates,” Water Science & Technology, 73.7, 1560 – 1571, 2016

This paper addresses a modified kinetic-hydraulic model for up-flow anaerobic sludge blanket (UASB) reactor aimed to treat wastewater of biodegradable organic substrates as acetic acid based on Van der Meer model incorporated with biological granules inclusion. This dynamic model illustrates the biomass kinetic reaction rate for both direct and indirect growth of microorganisms coupled with the amount of biogas produced by methanogenic bacteria in bed and blanket zones of reactor. Moreover, the pH value required for substrate degradation at the peak specific growth rate of bacteria is discussed for Andrews’ kinetics. The sensitivity analyses of biomass concentration with respect to fraction of volume of reactor occupied by granules and up-flow velocity are also demonstrated. Furthermore, the modified mass balance equations of reactor are applied during steady state using Newton-Raphson technique to obtain a suitable degree of freedom for the modified model matching with the measured results of UASB Sanhour wastewater treatment plant in Fayoum, Egypt.

Dr. Ahmed Radwan as a scientific Organizer at THE INTERNATIONAL CONFERENCE FOR MATHEMATICS AND APPLICATIONS (ICMA15)

MSA conference

Dr. Ahmed Radwan was a scientific Organizer at MSA Conference. The ICMA15 Conference serves as one of the principal international opportunities for presenting the interdisciplinary research and development activities that will shape tomorrow’s outlook at the junction of different fields of Mathematics, Physical Sciences, Computer Science, and Engineering. It brings together researchers and interested scientists from multiple academic universities and industries to spread the latest front-line research results and innovative solutions for today’s complex problems at the frontiers of many related fields for more details.

 

 

Accepted paper in International Computer Engineering Conference (ICENCO)

ICENCO 2016

NISC Center would like to congratulate Dr.  Ahmed  G.  Radwan, for his accepted papers in 11th  IEEE International Computer Engineering Conference (ICENCO), Egypt, 2015.


[1] Wafaa  S.  Sayed,  Ahmed  G.  Radwan,  Hossam  A.  H.  Fahmy,  “Design  of  a Generalized  Bidirectional  Tent  Map  Suitable  for  Encryption  Applications,”  11th  IEEE  International Computer Engineering Conference (ICENCO), Egypt, 2015.

Abstract:

The discrete tent map is one of the most famous discrete chaotic maps that has widely-spread applications. This paper investigates a set of four generalized tent maps where the conventional map is a special case. The proposed maps have extra degrees of freedom which provide different chaotic characteristics and increase the design flexibility required for many applications. Mathematical analyses for generalized positive and mostly positive tent maps include: bifurcation diagrams relative to all parameters, effective range of parameters, bifurcation points. The maximum Lyapunov exponent (MLE) is also calculated to indicate chaotic behavior. Various scales of the bifurcation diagram are discussed for each generalized map as well as system responses versus the added parameters.

Dr Ahmed Madian held a special session “Innov-Egypt” in ICECS 2015 funded by IEEE CASS outreach 2015

IEEE ICECS 2015 will include a demonstration session (Innovate Event: Inno-vent Egypt) that provided a forum to present and discuss prototypes, industry demonstrations of new applications and techniques, practical implementations, research testbeds and demonstrations, recent research/implementation results, and student senior year projects. Demonstrations of innovative ideas in all aspects of microelectronics and embedded systems are welcome. One of the key goals of this conference is to foster collaboration between industry and academia. Hence, the participation of researchers/senior year students/developers is especially encouraged. 10 participants were accepted for the workshop.

ICECS_2015

Dr. Ahmed Radwan held a Special Session in NOLTA 2015

Dr. Ahmed Radwan organized a Special Session in 2015 International Symposium on Nonlinear Theory and its Applications (NOLTA2015)Hong Kong, China, December 1-4, 2015