SUMMARYIn this paper a novel wideband recursive digital integrator and differentiator is presented. The integrator is obtained by interpolating three digital integration techniques and the new differentiator is obtained by modifying its transfer function appropriately. Both the integrator and the differentiator are of third order and highly accurate, thus suitable for real-time applications.

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Digital integrators (DIs) and digital differentiators (DDs) of second, third and fourth-order based on particle swarm optimisation (PSO) algorithm are presented. A modified particle swarm optimisation (MPSO) algorithm with reducing maximum velocity has been used to optimise the mean square error of the digital operators. Statistical and simulation results have been presented for comparing quality of optimal operators obtained by MPSO, genetic algorithm (GA), two variants of PSO and PSO-GA hybrid techniques. The results obtained for best solutions by the proposed algorithm are either superior or at par with the basic PSO variants and hybrid techniques. The proposed digital operators have also been simulated using MATLAB, and the results have been compared with that of existing DIs and DDs derived by different optimisation algorithms, to demonstrate the effectiveness of the use of proposed MPSO. The relative magnitude errors (dB) obtained for digital integrators and differentiators are as low as −40 and −35 dB, respectively, which are valid for almost the full band of normalised frequency.

SUMMARYIn this paper, new discretized models for fractional-order differentiator (FOD) (s r ) and integrator (FOI) (s −r ) using first-order and higher order operators are proposed. The expansions for FOIs of the first-order s-to-z transform proposed by Hsue et al. are obtained by using the Taylor series and continued fraction expansion techniques. Second-order Schneider operator and third-order Al-Alaoui-Schneider-KaneshigeGroutage (Al-Alaoui-SKG) rule have also been fractionalized to obtain expansions of FODs by using the Taylor series. Specifically, in this paper, Hsue operator based on third-order and fourth-order models of FOI, Schneider operator as well as Al-Alaoui-SKG rule based on third-order, fourth-order, fifth-order and sixth-order models of FOD have been suggested. The stability of the proposed models has been investigated and the unstable ones were stabilized by the pole reflection method. The performance of the proposed models has been compared with that of recent FOD and FOI models based on the Al-Alaoui operator. Performance results using the proposed discrete-time formulations are found to converge to the analytical results of FOD and FOI, in the continuous-time domain.

Thorough test and evaluation of new software-defined network (SDN)-based applications and configurations present many challenges. Examples of these challenges include scaling to large networks, accuracy, and efficiency in evaluation along with the ability to easily transition between prototype and test environments. Current methods for test and evaluation include new programming languages and frameworks, debugging and static analysis techniques, and VMand container-based emulation tools.In this paper we describe a simulation-based tool called fs-sdn that complements and expands upon these existing approaches. Our work is designed to address the problem of prototyping and evaluating new SDN-based applications accurately, at large scale, and in a way that enables easy translation to real controller platforms like POX and NOX. We describe the design, implementation and use of fs-sdn, and demonstrate its capability by carrying out a series of experiments using fs-sdn and the Mininet platform in nearly identical configurations. We show that the measurements derived from fs-sdn are accurate compared with Mininet, but offer significant speed and scalability advantages.

The paper presents new realizations of grounded negative capacitance, using current feedback operational amplifiers (CFOAs), two resistors and one capacitor. All the proposed realizations are canonic in the number of passive components and do not require any critical component matching condition. Application examples in capacitive cancellation schemes and resistance-controlled low-frequency quadrature sinusoidal oscillator design are provided. The workability of the circuits has been verified by PSPICE simulations.Keywords Active RC circuits · Grounded negative capacitance simulator (NCS) · Current feedback operational amplifier (CFOA) · Low-frequency quadrature oscillator (LF-QO)

Second and third order digital integrators (DIs) have been optimized first using Particle Swarm Optimization (PSO) with minimized error fitness function obtained by registering mean, median, and standard deviation values in different random iterations. Later indirect discretization using Continued Fraction Expansion (CFE) has been used to ascertain a better fitting of proposed integer order optimized DIs into their corresponding fractional counterparts by utilizing their refined properties, now restored in them due to PSO algorithm. Simulation results for the comparisons of the frequency responses of proposed 2nd and 3rd order optimized DIs and proposed discretized mathematical models of half integrators based on them, with their respective existing operators, have been presented. Proposed integer order PSO optimized integrators as well as fractional order integrators (FOIs) have been observed to outperform the existing recently published operators in their respective domains reasonably well in complete range of Nyquist frequency.

Proposed work deals with the design of a family of stable IIR digital integrators via use of minimax and pole, zero, and constant optimization methods. First the minimax optimization method is used to design a family of second-, third-, and fourth-order digital integrators by optimizing the magnitude response in a min-max sense under the satisfactory condition of constant group delay. Then the magnitude and group delay response is further improved using pole, zero, and constant optimization method. Subsequently, by modifying the transfer function of all of the designed integrators appropriately, new differentiators are obtained. Simulation results show that proposed approach outperforms existing design methods in terms of both magnitude and phase response.