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Purpose This paper aims to achieve accurate maximum power from solar photovoltaic (PV), its five parameters need to be estimated. This study proposes a novel optimization technique for parameter estimation of solar PV. Design/methodology/approach To extract optimal parameters of solar PV new optimization technique based on the Jellyfish search optimizer (JSO). The objective function is defined based on two unknown variables and the proposed technique is used to estimate the two unknown variables and the rest three unknown variables are estimated analytically. Findings In this paper, JSO is used to estimate the parameters of a single diode PV model. In this study, eight different PV panels are considered. In addition, various performance indices, such as PV characteristics, such as power-voltage and current-voltage curves, relative error (RE), root mean square error (RMSE), mean absolute error (MAE) and normalized mean absolute error (NMAE) are determined using the proposed algorithm and existing algorithms. The results for different solar panels have been obtained under varying environmental conditions such as changing temperature and constant irradiance or changing irradiance and constant temperature. Originality/value The proposed technique is new and provides better results with minimum RE, RMSE, NMAE, MAE and converges fast, as depicted by the fitness graph presented in this paper.

Order diminution (OD) or model order reduction (MOR), a very important field of System Engineering, has been explored by many researchers. Different methods are available for reducing the complexity of a control system, which are subsequently utilized to get a cost-effective controller. Model order reduction is done by either using classical methods or by using optimization techniques. In optimization algorithms, accuracy, complexity, and convergent rate are the main criteria for comparison in OD. This paper contributes a novel fast and more accurate OD (MOR) technique based on Salp Swarm Optimization. Further, the proposed method is applied to a time-delay system in four different manners. The effectiveness of the proposed technique is shown by reducing four benchmark systems, including a system with time delay and an 84th order system. Finally, the application of OD is shown by designing a reduced-based H-infinity controller for the 84th order system which results in a great saving of time ( $$\approx 96\%$$ ). The obtained results are comparable or better than those from the existing well-known order reduction techniques available in the literature.

In this study, a novel system reduction approach is suggested for a linear time-continuous system. Motivated by various optimization techniques and reduction problems in system engineering, a new search algorithm, namely ant lion optimization (ALO), is being utilized for system approximation. This algorithm is based on the random walk of an ant lion for searching the food. Firstly, the approximated system is formulated by reducing the integral square error (ISE) between the higher-order and proposed approximated system using ALO. To validate the high efficiency and accuracy of the suggested approach, it is tested on four benchmark systems maximum up to 84th order including a time-delay system. It is revealed that approximated system characteristics, achieved by the suggested approach, are much closer to the characteristics of the higher system. Further, it is also revealed that the transient, steady-state, and frequency response characteristics of the higher-order system are preserved by the suggested approximated system. Additionally, the lowest value of ISE is observed with the proposed approximated system as compared to other approximated systems already available. Furthermore, the efficacy of the suggested approach is also investigated in terms of final convergence rate and CPU usage time by employing well-known the genetic algorithm (GA) and particle swarm optimization (PSO) to obtain approximated systems.

Purpose This paper aims to suggest the parameter identification of load frequency controller in power system. Design/methodology/approach The suggested control approach is established using fuzzy logic to design a fractional order load frequency controller. A new suitable control law is developed using fuzzy logic, and based on this developed control law, the unknown parameters of the fractional order proportional integral derivative (FOPID) controller are derived using an optimization technique, which is being used by minimizing the integral square error. In addition, to confirm the effectiveness of the proposed control design approach, numerous simulation tests were carried out on an actual single-area power system. Findings The obtained results reveal the superiority of the suggested controller as compared to the recently developed controllers with regard to time response specifications and quantifiable indicators. Additionally, the potential of the suggested controller is also observed by improving the load disturbance rejections under plant parametric uncertainty. Originality/value To the best of the authors’ knowledge, the work is not published anywhere else.

The failure resilience in cloud computing is becoming mainstream due to unprecedented growth in the cloud. In order to enhance cloud service reliability, various fault tolerance techniques have bee...

A mathematical technique named the discrete-time system approximation is used for approximating higher-dimensional system to their lower-dimensional system by retaining the essential characteristics. Hence, a new hybrid technique is presented in this paper for discrete-time system approximation. The technique presented in this paper is developed by combining fuzzy C-means clustering (FCMC) and cuckoo search optimization (CSO) technique. Firstly, to get steady lower-dimensional system, the denominator polynomial is derived by FCMC technique. Secondly, the CSO technique is being employed to formulate numerator polynomial of the lower-dimensional/approximated system. The proposed hybrid method is tested on higher-dimensional test systems considered from the literature to derive lower-dimensional systems. Further, the efficiency of the suggested hybrid technique is justified on comparison of time domain characteristics and various performance indices. The time responses of higher- and lower-dimensional systems are plotted with respect to unit step input. It is observed that lower-dimensional system’s response derived from suggested hybrid method is found to be closed to the considered test system’s response. Furthermore, it reveals that the suggested hybrid technique gives the minimum performance indices values and hence has a better overall performance. One of the applications of the proposed hybrid method may be explored in the discrete-time interval system approximation.

In this article, a new system diminution technique is proposed for the reduction in complexity and controller design of the higher-order models. This method is based on the Mihailov stability method which ensures the stability of the obtained simplified/micro-model if the higher-order plant is stable. In this technique, the reduced characteristic equation of the simplified plant is obtained by using the Mihailov stability technique and the reduced numerator equation is determined by using the improved Pade approximation technique. By using this reduced-order model, the PID controller is designed for the large-scale system. The accuracy and effectiveness of the proposed method are validated by comparing the step responses of the complete and lower-order models. The performance of the recommended technique is shown in terms of step responses and performance error indices. Three standard numerical systems are finally provided to validate the effectiveness and accuracy of the designed controller and the performance of the proposed model-order reduction technique.

The Coulomb and Franklin laws (CFL) algorithm is used to construct a lower order model of higher-order continuous time linear time-invariant (LTI) systems in this study. CFL is quite easy to implement in obtaining reduced order model of large scale system in control engineering problem as it employs the combined effect of Coulomb’s and Franklin’s laws to find the best values in search space. The unknown coefficients are obtained using the CFLA methodology, which minimises the integral square error (ISE) between the original and proposed ROMs. To achieve the reduced order model, five practical systems of different orders are considered. Finally, multiple performance indicators such as the ISE, integral of absolute error (IAE), and integral of time multiplied by absolute error were calculated to determine the efficacy of the proposed methodology. The simulation results were compared to previously published well-known research.

Need of trusted and highly secured copyright protection techniques to prevent the illegal copying and sharing of digital data are highly required in recent years due to rapid development in internet technology. Here, lossless robust color image watermarking scheme using lifting scheme with grey wolf optimization (GWO) for copyright protection has been proposed. The insertion of color watermark has been done into the host image by changing the singular values of the host/cover image using optimized strength factor; alpha. To increase the security and robustness, scrambling of watermark has also been carried out by using Arnold transform along with GWO optimization technique in the presented work. Performance of presented work has been tested both quantitatively and qualitatively by using different fidelity parameters like; peak signal-to-noise ratio, structural similarity index and normalized correlation coefficient. The presented work has also been tested against various artificial attacks along with comparison with considered image watermarking techniques.

Order diminution plays a significant role in the study of complex dynamical linear interval systems. Numerous strategies have been suggested in diverse field for order diminution of higher dimensional models. Nowadays, the optimization algorithms are commonly used for order diminution based on a specific error performance criterion known as cost or objective function. This study suggests a novel approach for order diminution of interval system using cuckoo search algorithm. The proposed technique utilises the Kharitonov’s polynomials to ensure a stable model. Typical examples have been considered to showcase the efficiency of the presented approach. Comparative study is also demonstrated with other available techniques in terms of different performance measures. The suggested approach has also been applied for order diminution of multi input multi output interval system.

The work deals with six-level inverter topology for single phase standalone photovoltaic (PV) based micro system with reduced device count. Fundamental switching scheme has been presented using selective harmonic elimination-pulse width modulation (SHE-PWM) method to calculate the switching angles for optimization of harmonics and to eliminate the lowest order harmonic from the system. The Perturb and Observe algorithm is used for tracking the maximum power point for the triggering of DC–DC boost regulator conversion stage. Complete control scheme has been given with different modes of operation. The PV micro system has been simulated and tested in Matlab simulink environment. Total harmonic distortion analysis for the output voltage and current without and with filter has also been carried out for the system under test.

The world today depends on an uninterrupted flow of cost-effective and clean electricity. The rapid urbanization of the major population is placing more burden on the existing infrastructure-especially on the local power grids. The concept of microgrid reduces this burden to a greater extent but the voltage and transient stability of the system should always be maintained as this rising demand of uninterrupted electricity comes with more dynamic load fluctuations. The energy storage system of the microgrid can deal with this and could keep the bus voltage and transient stability under control. In this paper, battery and super-capacitor is used as energy storing devices and a fuzzy logic controller is proposed to determine the super-capacitor reference current to keep the DC bus voltage and transient within stability limits. It reveals that the results obtained by the proposed controller are comparable with that of the High Pass Filter.

Nowadays, with the advancement of technologies in modern life communication and networks, the secrecy of a cryptographic technique has become a strong necessity. The Vernam’s cipher which is a specific form of Vigenere cipher is gaining attention of researchers in the cryptography. But the modern encryption methods based on matrices available in the literature have their limitations to utilize them. Therefore, motivated by numerous cryptographic techniques available in the literature, this study presents a novel encryption approach for secure data communication. The proposed encryption approach is based on Vigenere cipher in finite dimensional vector space. Furthermore, the proposed approach relies on an eternal decomposition which is indiscriminate in the key selection inside key space. To add complexity by text scrambling, a weird substitution cipher key is added to provide maximum derangement in the encrypted text structure. Additionally, in the lights of Shannon’s secrecy, a comparison with usual matrix methods relying on $$LU$$ —decomposition and eigenvalue decomposition is also discussed to justify the perfect secrecy thus achieved. It is revealed that the proposed encryption approach is a more versatile and perfectly secret encryption scheme that roots on the widening of key space to a mathematical structure, which not only fulfills the completeness with respect to the proposed decomposition but identical to message space as well.

Reduced-order modelling is now becoming an important tool in almost all Engineering fields. Therefore, motivated by various real Engineering problems, this study contributes, a new classical approach of reduced-order modelling for continuous linear time-invariant (LTI) systems. The suggested method is based on the concept of direct comparison of the coefficients of the reduced and computational expensive higher dimension given system. In this method, the coefficients of the numerator and denominator of the original and the required reduced dimensional system are directly compared. Furthermore, the efficiency of the proposed method is observed not only when testing in a reference system with a linear continuous single-input single-output (SISO), but also in relation to the design of a controller in the power system. First of all, an automatic voltage regulator (AVR) used in power generation is reduced using the proposed method. The proposed AVR model is used to develop a proportional integral derivative (PID) controller for the original high-dimension AVR system. Also, an evolutionary algorithm, namely, particle swarm optimization (PSO), is used to search for unknown parameters such as Kp, Ki, and Kd of the PID controller taking Integral Time-Absolute Error (ITAE) as error criterion.

Due to fast development in digital technologies, numerous gateways are available to alter easily the contents of digital multimedia without noticeable changes by human beings. These features provide breakthrough to copy, store, and transmit digital data and also it has made illegal replication/distribution of digital content. Hence, digital rights management (DRM) is essentially required to solve the issues related to data security and owner’s authentication of multimedia resources and contents. In this paper, lossless color image watermarking scheme based on lifting scheme and grey wolf optimization (GWO) for copyright protection has been proposed. To optimize the strength factor, alpha, GWO has been used in proposed work. With optimized strength factor, the insertion of color watermark has been done into the host image by changing the singular values of the host/cover image. Scrambling of watermark has also been carried out by Arnold transform to provide more security and robustness. Performance analysis of presented work has been verified both quantitatively and qualitatively by using different fidelity parameters like, peak signal-to-noise ratio (PSNR), structural similarity (SSIM) index, and normalized correlation coefficient (NCC). To prove the strength, the present work has also been compared with considered image watermarking techniques.

This study contributes comparative analysis of controller design strategies for load frequency control (LFC) in the field of power engineering. In order to present the need of controller for frequency control due to variation in load, proportional integral derivative (PID), and FOPID controllers are discussed. Five different approaches, to design PID controllers, have been identified such as direct synthesis approach in frequency domain, Laurent series expansion, linear matrix inequality (LMI) approach, quadratic regulator approach with compensating pole (QRAWCP), and internal model controller (IMC) for comparative analysis. These techniques have been tested on reheated and non-reheated turbines of LFC. Furthermore, robustness of these techniques has been investigated by incorporating fifty percent perturbation in turbine model. The results are compared in terms of time response parameters. Additionally, the performance of PID controllers is compared with fractional-order (FO) PID controller available in the literature. It is concluded that FOPID controller has better performance.

In the present work, the application of a mixed/hybrid algorithm: grey wolf optimization-pattern search (hyGWO-PS) has been elaborated for automatic generation control (AGC) of three area interconnected hydro-thermal power system. The fractional-order proportional-integral-derivative (FOPID) controller has been incorporated in each area of the investigated power system and controllers’ parameters have been tuned/optimized using the hyGWO-PS algorithm. For this purpose, a constrained control optimization problem has been defined with minimum and maximum ranges of controllers’ parameters in which objective function: integral of time multiplied absolute error (ITAE) is minimized. The application of hyGWO-PS algorithm to tune the controllers’ parameters for the same is abbreviated as hyGWO-PS/FOPID approach. The results carried out using the proposed approach for the investigated system have also been compared with some existing approaches and the results reveal that the proposed approach: hyGWO-PS/FOPID for the aforesaid power system produces the better performance in terms of ITAE, settling times/peak overshoots, number of oscillations and speed of frequency and tie line power deviations while comparing with some other approaches in the literature. The percentage reduction in ITAE, settling times, and overshoots with respect to other techniques have also been evaluated which shows the improvement in aforesaid parameters with respect to other existing techniques.

Nowadays renewable energy sources have significant contribution in electrical engineering. The solar photovoltaic (PV) systems are in great demand as a non-conventional energy source. The performance of solar PV system is highly affected by temperature and irradiance in the surroundings. This may also leads to change the maximum available power of PV system. To achieve maximum power, this paper contributes a new control design strategy for MPPT of solar PV systems. The concept of fuzzy logic is being employed to design suitable control law. The performance of designed controller is tested with wide range of environmental parameters change. It is observed that the obtained results not only provide the fast dynamics but also high accuracy in power is achieved.

Time moments and Markov parameters play two important roles in the simplification of large-scale system. First role plays in the matching of steady-state responses of the full order and reduced order plants; for this, the matching of their initial few time moments are required. The matching of transient responses between the complete order and lower order systems is the second role of the time moments and Markov parameters. For the second role, the Markov parameters of the actual order and lower order plants must be matched. In this contribution, it is shown that the time moments are not only responsible for the matching of static responses but also for the matching of transient responses. For better understanding of the contribution of the time moments and Markov parameters, popular examples are taken from literature and in each examples, proposed concepts are explained. A new system diminution technique is also proposed which may be applicable when the Pade approximation methodology fails. The process of obtaining reduced plant by this method is based on matching of Markov parameters in place of time moments matching.

In power electronic circuit design and analysis, Cuk converter has significant contribution. This convert is used to obtain variable DC voltage. The conventional modelling of Cuk converter provides complex linear model. Therefore, this study suggests a method for modelling of DC–DC Cuk converter via system approximation approach. Firstly, the high dimensional complex model of Cuk converter is discussed then its approximated transfer function model is achieved using a hybrid approach. In this approach, the combination of Routh approximation method and meta-heuristic search optimization is utilized for modelling of Cuk converter. The performance characteristics of proposed approximated model are compared with previously presented models.

In this paper, stochastic fractal search (SFS) algorithm has been applied for optimal tuning of the parameters of two dissimilar PI controllers in automatic generation control (AGC) of interconnected thermal power systems with ITAE as objective function. The performance of the proposed SFS tuned PI controller for the same has also been compared with some popular techniques existing in the literature. From the simulation results, it has been found that the PI controllers optimized/tuned by the SFS produces less ITAE value, settling times, smooth dynamic response, less oscillations, and fast dynamic response when compared with some popular approaches in the literature for the same considered system and ITAE.

This paper presents an online estimation of density and viscosity from the sensor response based on artificial neural network approach. The working principle of sensor is based on the vibration of piezoelectric actuated cantilever beam at resonance. In addition to that, an Artificial Neural Network approach is utilized for the online estimation of unknown viscosity and density of liquids, based on the dynamic characteristics of the resonant cantilever sensor. The estimation of density and viscosity of unknown liquid is done by the observing the dynamic characteristics of the cantilever vibration which greatly depends on the Q factor and frequency of the cantilever vibration at resonance. The dynamic characteristics of the piezo actuated cantilever sensor is analysed using Euler–Bernoulli beam equations. In this study, the back propagation neural network (BPNN) has been used for the online estimation of the liquid viscosity and density. By the neural network training, it is possible to estimate the accurate density and viscosity of unknown liquid with dynamic response of the beam at any conditions. The output obtained from neural network models are compared with analytical results.

A new system simplification hybrid method is proposed in this article. In this hybrid method, the advantages of two different approaches are being employed in order to simplify the higher dimensional systems. The unknown constant of denominator polynomial is derived using Routh stability whereas improved Pade approximation is employed to achieve numerator polynomial coefficient of the targeted simplified/micro-system. The proposed hybrid method is validated by simplifying standard higher dimensional systems available in the literature. It reveals that the simplified/micro-system derived by using proposed hybrid method holds the essential characteristics of original system that is stability and time response specifications.

To prevent the illegal copying and sharing of digital content, the need for security for digital data is highly demanded. Among various available techniques, digital watermarking is an effective solution to protect confidential data. This paper presents the performance analysis of color image watermarking based on lifting scheme in which color image watermark has been used. Peak signal-to-noise ratio (PSNR), Structural similarity (SSIM) index and normalized correlation coefficient (NCC), etc. have been used as fidelity parameters to test the effectiveness of presented work both quantitatively and qualitatively.

Angular correlations serve as a very important tool to study the complex dynamics of particle collisions at colliders, which is not very well understood. Angular correlation is generally quantified in terms of the ∆η and ∆O. In the current paper, Monte Carlo events using simulator Pythia are generated and studied in terms of the variables sensitive towards the angular correlations.

In the present study, a new approach is suggested for the prediction of virtual machine (VM) failure based on the time series stochastic model. Motivated by various proactive fault tolerance techni...

Due to fast technological development, human beings generally depend upon computer and other digital equipments in different areas of concern/applications. Therefore, various issues related to authentication and information security are raised with multimedia content in defence as well as in civil arena. In present work, a non-blind Arnold scrambling incorporated hybrid image watermarking technique has been proposed to improve the security and robustness. Here, color image as a watermark has been used instead of binary or gray image. To enhance the correlation between original host/cover and watermarked image, YCbCr color model has been chosen to separate channels of RGB image. Y channel has been used for embedding the singular values of watermark into the corresponding value of host/cover image using variable scaling factor (α). For more security aspect, number of iterations in Arnold transform have been included as a key for scrambling the watermark image prior to its embedding. Present work requires the original image for extraction of watermark hence the proposed work comes into the non-blind category. To calculate the imperceptibility, fidelity parameters such as; peak signal- to- noise ratio (PSNR) and structural similarity (SSIM) have been chosen whereas normalized correlation coefficient (NCC) have been used to calculate the similarity between original and extracted watermark. For robustness check, the proposed technique has also been tested against various attacks. The simulated results have also been compared with some of the existing color image watermarking techniques. The experimental outcomes prove the usefulness of the proposed image watermarking technique.

Firstly, this paper develops a robust fractional order proportional integral derivative (FOPID) controller for automatic voltage regulator (AVR) in power systems. In the proposed controller, optimum design parameters, such as, proportional, integral, derivative gains, integral and derivative constants, have been achieved by using cuckoo search (CS) algorithm. Then, the time response characteristics of AVR with and without proposed controller have been investigated to reveal the effectiveness of the proposed controller. Also, the performance of the proposed controller has been tested under the condition of the parameter uncertainty and improved performance has been revealed. Finally, the accuracy and robustness of the proposed controller has been investigated through the comparative analysis of the results, achieved from proposed and other existing controllers using the same sets of data. It is shown that the proposed controller provides the better time response characteristics than the other existing techniques.