International Journal of Systems, Control and Communications (21 papers in press)

Regular Issues

• Improved finite frequency Hoo filtering for Takagi-Sugeno fuzzy systems  
  by Abderrahim EL-AMRANI 
  Abstract: This paper investigates the design problem of Hoo filtering for discrete non-linear systems in the Takagi-Sugeno (T-S) form. Our aim is to design a new filter guaranteeing an Hoo performance level in specific finite frequency (FF) ranges. Using the well-known generalised Kalman Yakubovich Popov lemma, Finslers lemma, sufficient conditions for the existence of Hoo filters for different FF ranges are proposed and then unified in terms of solving a set of linear matrix inequalities (LMIs). Two examples are given to illustrate the effectiveness and the less conservatism of the proposed approach in comparison with the existing methods.
  Keywords: Finite Frequency; Hoo Filtering; Takagi-Sugeno (T-S) Fuzzy Systems; Linear Matrix Inequalities (LMIs).
  
  
• Leader-Follower Formation Suboptimal Control for Quadrotors  
  by Wesam Jasim, Dongbing Gu 
  Abstract: In this work, a leader-follower formation control problem of quadrotors is investigated. The quadrotor dynamic model is represented by unit quaternion with the consideration of external disturbance. Nonlinear $H_{\infty}$ design approach is introduced and robust controllers for both leader and follower robots are derived by solving a Hamilton-Jacobi inequality following from a result for general nonlinear affine systems. Then some robustness conditions of the proposed controllers are obtained by selecting appropriate parametrised Lyapunov functions. The resultant state feedback controllers establish the asymptotically stability of the closed-loop nonlinear system. In addition, integral backstepping (IB) controllers are also derived for the leader-follower formation control problem. The purpose of designing IB controllers is to evaluate the robustness of $H_{\infty}$ controllers by comparison. The simulation results from both types of controllers are compared and robustness performance of the $H_{\infty}$ controllers over the IB controllers are demonstrated.
  Keywords: leader-follower formation; integral backstepping; H_infinity controller; unit quaternion; quadrotors.
  
  
• Analytic Hierarchy Process Based Model Reduction of Higher Order Continuous Systems Using Sine Cosine Algorithm  
  by Tapan Prakash, S.P. Singh, V.P. Singh 
  Abstract: The analysis of higher order systems is tedious and cumbersome task. This motivated analysts to reduce higher order systems into lower order models using mathematical approaches. In this paper, an analytic hierarchy process (AHP) based approximation of stable higher order systems to stable lower order models using sine cosine algorithm (SCA) is presented. The stable approximant is deduced by minimizing the relative errors in between time moments and Markov parameters of the system and its approximant. In order to match the steady states of the system and its approximant, the first time moment of the system is retained in the approximant. AHP is utilized to convert multi-objective problem of minimization of errors in between time moments and Markov parameters into a single objective problem by proper assignment of weights. To ensure the stability of the approximant, Hurwitz criterion is utilized. The systematic nature and efficacy of the proposed technique is validated by deriving approximants for three different test systems.
  Keywords: Analytic hierarchy process; model reduction; Padé approximation; Routh approximation; sine cosine algorithm.
  
  
• Low power Experimental Prototype of a controlled Three- Phase Inverter using D.S.P (TMS320F2812) for a Hydraulic Energy Conversion Chain Application  
  by Chirine BENZAZAH, Loubna LAZRAK, Soukaina EL DAOUDI, Mustapha AIT LAFKIH 
  Abstract: This paper deals with a part implementation of the distributed generation chain system based on hydraulic power source operated in low power and controlled by DSP F2812. The experimental part of the chain includes a controlled two-level three phase inverter connected, via an LC filter, to a load. This latter consists of a balanced three phase resistive without neutral point joint, for this reason, the implementation requires fewer sensors as measuring devices. The proposed control strategy uses just two regulation loops; one of them is for the AC output voltages and the other one is for the input inductor currents of LC filter. This strategy was developed on Matlab-Simulink and implemented in eZdsp TMS320F2812 DSP board from Spectrum Digital. To confirm the efficiency and robustness of the chain part implementation, the experimental results using the implemented inverter was compared with a compact industrial module 7MBR15SA120 inverter mounting with the same control interface and measurement cards. The experimental waveforms comparison prove that there is a good match between the two practice prototypes, validate the theoretical study as well as the simulation results obtained and confirm the effectiveness of the proposed control strategy.
  Keywords: (three phase inverter; DSP F2812 controller; CCS; MATLAB interface; Digital model; Power Integrated Module 7MBR15SA120; IRGPS60B120KDP).
  
  
• Performance Superiority of CA_TM Model Over N-P Algorithm in Detecting 2 Fluctuating Targets with Four Degrees of Freedom  
  by Mohamed El_Mashade 
  Abstract: The receiving of targets information mixed with undesired contribution of clutter causes affects the operation of radar systems. Modern radars have adopted adaptive processing techniques to mitigate the deleterious effects of the unwanted clutter and jammer. In this regard, the CFAR processors play a vital role in organizing the detection of fluctuating targets in heterogeneous background environments. Specifically, the popular CA-CFAR processor is incapable of maintaining its design false alarm probability when facing clutter with statistical variations. OS and TM algorithms have been suggested to achieve robust estimates of the threshold in heterogeneous situations. These techniques, however, do not fully utilize the a priori information related to the clutter distribution resulting in degradation in their detection performance in homogeneous clutter. In order to simultaneously exploit the merits of CA, and OS or TM processors, a hybrid combination of them have been recently proposed. They are named as CA_OS and CA_TM approaches. This paper is devoted to the analysis of these new models in the case where the radar receiver post-detection integrates M-pulses to carry out its object. Closed-form expression is derived for their detection performance. The primary as well as the outlying targets are assumed to be fluctuating following χ2-distribution with four-degrees of freedom in their fluctuation. Our simulation results reveal that the new version CA_TM exhibits a homogeneous performance that outweighs that of the classical Neyman-Pearson (N-P) detector which is employed as a baseline comparison for other techniques in the CFAR world.
  Keywords: adaptive processors; clutter and interference; derived detectors; χ2-distribution; Swerling models; SWIII & SWIV; postdetection integration of M pulses; multitarget environments.
  
  
• Robust Output Feedback Control for Uncertain Chaotic Systems  
  by Mohammad Salah, Hazem El-Hageen, Osamah Badarneh, Mohammad Ababneh, Mohammed Abu Mallouh 
  Abstract: Chaos phenomena can be found in many scientific disciplines such as astronomy, biology, chemistry, engineering, geology, mathematics, medicine, meteorology, and even social sciences. Such phenomena can seriously affect the behavior of some vital applications such as communications and security systems. Hence, a controller is required to handle chaotic behaviors that affect systems stability. In this paper, a robust output feedback controller is proposed to stabilize electronic circuits used in communications and security systems that exhibit chaotic behaviors. The proposed controller is designed to deal with unknown system parameters and time-varying uncertainties. Only the system output is utilized in the proposed controller and other states are estimated. Therefore, a high gain observer is utilized. Numerical study is introduced in this paper to demonstrate the robustness and effectiveness of the proposed controller. The controller performance is investigated under various system configurations and different operating conditions and a satisfactory tracking is observed.
  Keywords: chaotic system; control of sprott circuit; robust control; output feedback control; high gain observer.
  
  
• Adaptive Neural network control for a class of MIMO Non-affine uncertain systems with input dead-zone nonlinearity and external disturbance  
  by Zerari Nassira, Mohamed Chemachema, Najib Essounbouli 
  Abstract: This paper studies an adaptive tracking control for a class of multi-input multi-output (MIMO) non-affine nonlinear systems, with input Dead Zone nonlinearity and external disturbances. By using the mean-value theorem, the system model is transformed into an affine form so as the difficulty in controlling non-affine systems is overcome. In the proposed control design, neural networks (NNs) are used to approximate the unknown nonlinearities based on their universal approximation properties. To compensate for approximation errors and external disturbances, an adaptive robust control term is introduced. In comparison with existing approaches, the structure of the designed controller is considerably simpler, and can handle a wider range of nonlinear systems. The stability of the closed-loop system is investigated by using Lyapunov theory. The simulation results illustrate the proposed method.
  Keywords: Adaptive control system; Neural networks; Multi-input Multi-output (MIMO) unknown non-affine Systems; Dead Zone input.
  
  
• Scalable Energy Efficient Routing Mechanism Prolonging Network Lifetime in Wireless Sensor Networks  
  by Omkar Singh, Vinay Rishiwal 
  Abstract: Due to the tiny size, nodes in a Wireless Sensor Network (WSN) are restricted in battery capacity. As a result, a node and in turn a network of such nodes is not operational for a long time. Further, in some hostile area battery cannot be replaced easily once deployed. Therefore, an energy conservation scheme or algorithm is needed to prolong the network lifetime. In this paper, an Energy Efficient Routing Scheme (EERS) is proposed and evaluated. This scheme extends the lifetime of network by selecting the finest shortest path to transmit data packets to the destined nodes. EERS selects a path/quality link over which it has minimum number of hops with maximum remaining energy over that path. Proposed scheme EERS is compared with other existing schemes for different parameters and varying size of network (100-1000 nodes). The Simulation results shows that the EERS scheme prolongs the network lifetime 10%-15% as compared to other considered schemes. EERS also minimizes the delay for transmitting data packets and increases the packet delivery ratio.
  Keywords: WSN; Routing; Energy; DEEC; EESAA; EAP; EERS.
  
  
• Delay-Dependent Admissibility And Control of Discrete-Time Switched Singular Systems with Time-Delay.  
  by Chaibi Noureddine, Charqi Mohammed, Ouahi Mohamed, Tissir Elhoussaine 
  Abstract: This paper is concerned with the problems of Admissibility and Control for a class of Discrete-time Switched Singular Systems with Time-Delay for arbitrary switching law. Firstly, a new delay-dependent sufficient condition is established in terms of linear matrix inequalities (LMIs) by constructing a novel Lyapunov- Krasovskii functional so that the discrete-time Switched Singular Systems with time-delay to be regular, causal and asymptotically stable. The proposed criterion is proved to have some advantages over other existing results. Then, a state feedback controller is designed to guarantee the admissibility of the closed-loop Switched Singular Delay System, by using the skills of matrix theory. Some slack variables are introduced for more relaxation. Finally, Numerical examples are provided to demonstrate the effectiveness of the proposed approach and to compare the obtained results with some existing ones in the literature.
  Keywords: Discrete-time Switched Singular Systems; Switching signal; Lyapunov-Krasovski functional; Time-Delay; Admissibility; Causality; Regularity; Stability Asymptotic; State Feedback Control; Linear Matrix Inequality (LMI).
  
  
• Control of PMSG wind electrical system in network context and during the MPP tracking process  
  by Youssef Errami, Abdellatif Obbadi, Smail Sahnoun 
  Abstract: The rapid growing of wind power industry makes the research area of Wind Electrical System (WES) control more attractive to researchers. This study presents a control strategy for grid-connected WES based on a Permanent Magnet Synchronous Generator (PMSG). The power system comprises five PMSG based 2MW which connected to the dc bus with rectifiers, whereas the grid-side inverter is connected to the power grid throughout a grid-side filter. The objectives of grid side inverter are to deliver the energy from the PMSGs side to the power grid, to regulate the dc-bus and to achieve unity power factor (UPF). It can separately control reactive and active power production. The generator side converters are employed to control the velocities of the PMSGs with Maximum Power Point Tracking (MPPT) algorithm to maximize the extracted power from Wind Turbine Generator (WTG) under low, medium or high wind velocity mode. Moreover, a pitch control algorithm is proposed so as to limit the excess of wind power above rated wind speed conditions and to prevent wind turbines damage from excessive wind velocity. We give a complete model of the WES and present Vector Control Technique (VCT) approach for both the generator and grid side converters. Then, the proposed VCT strategy is able to fully decouple the quadrature (q) and direct (d) components of the currents. Simulations results using MATLAB/Simulink software are presented and discussed to validate the proposed control scheme for fault conditions into the grid as well as for normal working conditions.
  Keywords: Wind Electrical System; PMSG; MPPT; VCT; fault electric network.
  
  
• Receding horizon control based on the variational iteration method  
  by Rima TERKMANI, Ahmed MAIDI, Saïd GUERMAH, Mohamed AIDENE 
  Abstract: In this paper, a new indirect method is proposed for the receding horizon control of dynamical systems. It consists in solving, over a control horizon, the optimality conditions using the variational iteration method. The optimality conditions are given by the Euler-Lagrange equations and their associated boundary conditions. This two-boundary values problem is solved iteratively using a correction functional that yields both the optimal state and the optimal control. Then by imposing, at each sampling time, the current boundary conditions, a system of algebraic equations is obtained and solved, which allows to define the piecewise optimal control to be applied at the current sampling time. The effectiveness of the proposed approach is illustrated by two application examples.
  Keywords: receding horizon control; model predictive control; optimal control; calculus of variations; Euler-Lagrange equation; variational iteration method.
  
  
• An Adaptive algorithm for energy efficient network selection in heterogeneous networks  
  by Silki Baghla, Savina Bansal 
  Abstract: In heterogeneous environment, mobile terminals should be equipped with multiple interfaces to have requisite services from available networks. This flexibility is achieved at the cost of significant power consumption at network side as well as mobile terminals. Energy consumption of mobile terminal increases with increase in simultaneous connections as well as user applications. When a user roams in the overlapping area of different networks, it is required to maintain service continuity with the network which offers requisite quality of service and maximum lifetime to the mobile terminal. So, a VHO technique, which provides optimum network selection by considering user's preferences and at the same time is able to adapt to the current battery status is the need of the day. In this work, an adaptive algorithm for network selection is proposed which provides a balance between desired quality of service (QoS) with the present battery level of mobile terminal. Vector normalized preferred performance based VIKOR algorithm (V-VPP) is used as a baseline algorithm for energy efficient network selection. Performance of V-VPP is also compared with conventional multiple attribute decision making algorithms on the bases of number of handovers, lifetime and network selection.
  Keywords: Vertical handover; Heterogeneous; Next generation; QoS ; VIKOR; V-VPP.
  
  
• A Review of Hardware Platforms for Wireless Ad Hoc Mobile/Sensor Networks  
  by Mousami Vanjale, Shilpa Gaikwad, J.S. Chitode 
  Abstract: Mobile ad hoc network (MANET) is a self-organized wireless communication network (WCN) without any fixed infrastructure. The nodes in MANET are small, battery operated and autonomous. They can sense, process and communicate wirelessly. The applications of MANETs include battle field communication, rescue operations, and information exchange at conference or classroom. Ease of deployment without any need of physical infrastructure makes MANETs a popular choice for WCN. Constraints like limited battery power, lack of centralized control, need of specialized routing protocols etc., impose research challenges on large physical deployment of MANETs. Tools such as simulation, emulation and real world implementation, help in finding solutions to face these challenges. Selection of appropriate tool often consumes a lot of time. This paper contributes a detailed review of various hardware platforms with their attributes and applications. This will help the researchers to select an appropriate hardware platform for their intended application.
  Keywords: Review; hardware platforms; wireless ad hoc network; sensor network; MANET; physical deployment; real world implementation; IEEE 802.15.4; ZigBee; sensor/s.
  
  
• Wireless Backhaul Networks: Centralized Vs Distributed Scenario  
  by Gitimayee Sahu, Sanjay S. Pawar 
  Abstract: The ultra-dense network (UDN) has been considered as a promising candidate for future 5G Network to meet the explosive data demand. To realize UDN, a reliable, Gigahertz (GHz) bandwidth and cost-effective backhaul network connecting ultra-dense small-cell BSs (SBS) and Macrocell BS (MBS) are pre-requisite. Millimeter wave (mmWave) spectrum can be used to obtain potential Gigabit-per-second (Gbps) traffic for wireless backhaul. Moreover, mmWave can easily integrate with massive MIMO for improved link reliability. In this research work, we analyze the wireless backhaul traffic in two different scenarios (e.g., centralized and distributed) using small cell and mmWave communication. Furthermore, the energy efficiency (EE) of wireless backhaul network is compared for different network architecture and frequency bands. Numerical comparison results provide some guidelines for deploying future 5G wireless backhaul network in economical and highly energy-efficient way.
  Keywords: Centralized network; distributed network; Energy efficiency; Wireless backhaul network.
  
  
• VLSI implementation of an efficient MBIST architecture using RLFSR  
  by Nisha O.S, K. Siva Sankar 
  Abstract: An area and power efficient FPGA implementation approach of memory built in self test (MBIST) is presented in this paper. It is consist of an array of 2 bit linear feedback shift register (LFSR), the switching activity of address generator used in previous MBIST architectures are high. This unwanted switching activity is affecting the power consumption of entire MBIST. We propose the MBIST with ring based LFSR used to avoid the main problem of power consumption. The 2-bit 2N pattern generator combines with a conventional (N-2) bit 2 (N-2) LFSR and a 2-bit 4 pattern generator are both controlled separately by a two separate clocks of two different frequencies to generate all possible memory address location of a memory under test. The proposed architecture is implemented on vertex4 FPGA technology in Xilinx software. We showed that results improve the performance of the proposed design by comparing with the existing design
  Keywords: Memory built in self test (MBIST); Ring LFSR (RLFSR); 2D-LFSR; switching activity; FPGA; Xilin.
  
  
• A conceptual framework for securing industrial control systems: smart grid environment  
  by Saqib Ali, Mohammed Al Abri 
  Abstract: Cyber physical systems (CPSs) utilised in many of the critical infrastructures including the smart grid. The operational activities of smart grid's CPS use different industrial solution such as industrial control systems (ICS) for monitoring and controlling the physical architecture of smart grid. Therefore, it is quite essential to keep these industrial control systems secure and safe from potential hazards and cyber world as it may be harmful for human safety, strategic infrastructure of a country and also for the economy. The study gathered the scattered guidelines, best practices and policies available from various organisations such as National Institute of Standards and Technology (NIST), ISO, and North American Electric Reliability Corporation (NERC) for the purpose of developing safe and secure ICS security systems and also the knowledge about the issues involved in ICS security and protection. A conceptual framework is proposed and developed to address the shortcomings in-order to protect the ICS systems in a smart grid environment. The proposed framework was developed by reviewing related studies, standards and utilising IT security working experience. This framework will not only expand the horizon of knowledge but also provides pathway for the development of existing activities of CPS applications such as smart grid.
  Keywords: industrial control systems; ICS; supervisory control and data acquisition; SCADA; cybersecurity; cyber physical systems; CPSs; smart grid.
  DOI: 10.1504/IJSCC.2019.10021994
   
  
• Optimisation of PTS technique for PAPR reduction in MIMO-OFDM-based CRNS  
  by Sharanjit Kaur, Inderdeep Kaur Aulakh 
  Abstract: In CRNs, the available spectrum has to be shared between various users, OFDM has a feature that supports multiuser access by assigning subcarriers to different users. In wireless transmissions, PAPR is the key challenge in OFDM that affects the BER. In this paper, the main focus is on PTS. The drawback of existing PTS technique is that the number of multiplications of IFFT sub-sequences with the phase vectors required in it are very high. To reduce computational complexity, optimisation is performed. BPSO is used to find optimised phase vector. This phase vector will be one having reduced PAPR. The purpose is to find out the absolute convergence of MIMO multiplexing to reduce the internal phase to phase PAPR in cognitive radio based networks. Results show that in case of PTS-BPSO error reduces at higher rate with less PAPR. BER is reduced at different SNR values as compared to conventional approach.
  Keywords: orthogonal frequency division multiplexing; OFDM; partial transmit sequence; PTS; binary particle swarm optimisation; BPSO; particle swarm optimisation; PSO; peak-to-average power ratio; PAPR; bit error rate; BER.
  DOI: 10.1504/IJSCC.2019.10021995
   
  
• Design of an automatic voltage regulator based on symmetric root locus technique  
  by Rittu Angu, R.K. Mehta 
  Abstract: An automatic voltage regulator (AVR) design based on symmetric root locus (SRL) technique for a synchronous machine infinite bus (SMIB) power system is presented. The SRL technique is used to minimise the amplifier saturation by placing the closed-loop poles (CLPs) of the system at desired locations. The desired CLPs are decided by considering the dominant pole locations that provide maximum damping on the SRL plot. The design incorporates an extended estimator to deal with uncertainties introduced due to variations of parameters or operating conditions. They reconstruct the state information including the state of disturbance dynamics simultaneous to implement full state feedback and using the reconstructed disturbance estimate to compensate the effect of external disturbance or parameter uncertainties. The performance of the system is analysed through simulating at different operating conditions. The control method improves the tracking response and provides zero estimation error in the steady-state. Illustrative examples have been provided to demonstrate the effectiveness of the developed methodology.
  Keywords: synchronous machine infinite bus; SMIB; automatic voltage regulator; AVR; symmetric root locus; SRL; extended estimator.
  DOI: 10.1504/IJSCC.2019.10022001
   
  
• Precoded GFDM system for self-interference mitigation  
  by Mohsen Farhang, Hossein Khaleghi Bizaki 
  Abstract: Generalised frequency division multiplexing (GFDM) is a multicarrier transmission scheme that offers a flexible framework to address diverse requirements of fifth generation of cellular networks. Compared to orthogonal frequency division multiplexing (OFDM), the application of pulse shaping in GFDM can control the out of band (OOB) radiation and enables relaxed synchronisation requirements. However, the sub-carriers in GFDM are no longer orthogonal and there is inherent interference. Since this interference is known at the transmitter, it can be mitigated by means of precoding techniques. In this paper, Tomlinson-Harashima precoding (THP) scheme is applied to GFDM transceiver and its performances is compared to previous methods in terms of bit error rate (BER) and peak to average power ratio (PAPR). The results show that the proposed precoder outperforms previous methods in both BER and PAPR.
  Keywords: generalised frequency division multiplexing; GFDM; precoding technique; non-orthogonal waveform; self-interference.
  DOI: 10.1504/IJSCC.2019.10022002
   
  
• Anti aging controllable true random number generator for secured AES-based crypto system  
  by Muthukumar Arunachalam, Sivasankari Narasimhan, Rampriya Kaniram 
  Abstract: A tetrahedral oscillator-based true random number generator for secret key generation in cryptosystem has been proposed. The circuit is made to behave correctly for a long time. By applying pass transistors, the aging effects due to hot carrier injection (HCI) and negative bias temperature instability (NBTI) are reduced. This fact is helpful to achieve the goal and its performances have also been improved. Pass transistor makes the transistors to operate only at enabling times. Thus, bit flipping in normal designs are reduced. Due to the complexity in the tetrahedral oscillator hacking will be very tough. The secret key generated from TRNG circuit is adopted in advanced encryption standard (AES) cryptosystem to maintain an off-chip database. Moreover, controlling circuits for TRNG have been introduced because in any of the cryptosystem man-in-middle attack is possible. To avoid this controlling circuits are used to identify the authenticity of customers. Simulation results explain that our aging resistant design can be used for generating more reliable keys. Although the operating conditions changes, the DC operating point of the system does not change more. The randomness is also shown through NIST tests.
  Keywords: aging; advanced encryption standard; AES; cryptosystem; personality ID; TRNG; hash function; tetra hedral oscillator; sampling; pass transistors; operating point.
  DOI: 10.1504/IJSCC.2019.10022004
   
  
• Robust finite frequency H_∞ filtering for uncertain continuous-time systems  
  by Kaoutar Lahmadi, Abderrahim El-Amrani, Bensalem Boukili, Ismail Boumhidi 
  Abstract: In this paper, the H_∞ filtering problem for a class of continuous-time polytopic uncertain systems is studied. Different from the traditional methods dealing with polytopic uncertainties in the full frequency domain, not only its values but also the finite frequency (FF) cases are considered. Our goal is to design a the filters guaranteeing an H_∞ performance level in the finite frequency (FF) domains. By using the generalised Kalman-Yakubovich-Popov (gKYP) lemma, polynomially parameter-dependent Lyapunov function and some key matrices, we establish new sufficient conditions to characterise this problem in terms of linear matrix inequalities (LMIs). Finally, a two examples are used to show the superiority and effectiveness of the proposed methods.
  Keywords: finite frequency; H_∞ performance; continuous-time systems; linear matrix inequalities; LMIs.
  DOI: 10.1504/IJSCC.2019.10022005