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Effective capacity of delay-constrained cognitive radio links exploiting primary feedback

In this paper, we study the effective capacity (EC) of cognitive radio (CR) networks operating under statistical quality-of-service (QoS) constraints in an attempt to support real-time applications at the secondary users (SUs). In particular, we analyze the performance gains, in terms of EC and average transmitted power, attributed to leveraging the primary user (PU) feedback overheard at the SU

Software and Communications

On optimal policies in full-duplex wireless powered communication networks

The optimal resource allocation scheme in a full-duplex Wireless Powered Communication Network (WPCN) composed of one Access Point (AP) and two wireless devices is analyzed and derived. AP operates in a full-duplex mode and is able to broadcast wireless energy signals in downlink and receive information data in uplink simultaneously. On the other hand, each wireless device is assumed to be

Software and Communications

Reactance-less RM relaxation oscillator using exponential memristor model

Recently, the memristor based relaxation oscillators become an important topic in circuit theory where the reactive elements are replaced by memristor which occupies a very small area. In this paper, a design of memristor-based relaxation oscillator is introduced based on exponential memristor model. Unlike previously published oscillators which were built based on a simple memristor model, the

Circuit Theory and Applications

On The Optimization of Fractional Order Low-Pass Filters

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

Circuit Theory and Applications

Aging effect on apples bio-impedance using AD5933

In this paper, the effect of the fruits aging on bio-impedance is experimentally studied. Bio-impedance analysis, as accurate and fast method is used to investigate and monitor group of apples properties during aging. This method provides an alternative method for investigating apples physical properties that are highly related to chemical properties. AD5933 impedance analyzer chip within the

Circuit Theory and Applications
Software and Communications

Fundamentals of fractional-order LTI circuits and systems: number of poles, stability, time and frequency responses

This paper investigates some basic concepts of fractional-order linear time invariant systems related to their physical and non-physical transfer functions, poles, stability, time domain, frequency domain, and their relationships for different fractional-order differential equations. The analytical formula that calculates the number of poles in physical and non-physical s-plane for different

Circuit Theory and Applications

Analysis and realization of a switched fractional-order-capacitor integrator

Using fractional calculus, we analyze a classical switched-capacitor integrator when a fractional-order capacitor is employed in the feed-forward path. We show that using of a fractional-order capacitor, significantly large time constants can be realized with capacitances in the feedback path much smaller in value when compared with a conventional switched-capacitor integrator. Simulations and

Circuit Theory and Applications

Image encryption algorithms using non-chaotic substitutions and permutations

This paper presents substitution and/or permutation symmetric-key encryption algorithms based on non-chaotic generators. While the substitution algorithm is based on fractals with delay and multiplexer elements, permutations are achieved via a chess-based algorithm. A comparison of four different cases; substitution-only, permutation-only, substitution-permutation and permutation-substitution; is

Circuit Theory and Applications

Generalized synchronization involving a linear combination of fractional-order chaotic systems

In this paper, a generalized scheme for synchronizing a fractional order chaotic system with another one or with a linear combination of two other fractional order chaotic systems is presented. Static (time-independent) or dynamic (time-dependent) synchronization that could generate multiple scaled versions of the response is discussed for some fractional order continuous chaotic systems based on

Circuit Theory and Applications

Double-sided bifurcations in tent maps: Analysis and applications

The tent map is a piece-wise linear one-dimensional discrete map which could be implemented easily. In this paper, a signed system parameter is allowed leading to the appearance of bidirectional bifurcations. A set of proposed tent maps with different sign variations and a signed parameter are investigated where the conventional map is a special case. The proposed maps exhibit period doubling as a

Circuit Theory and Applications