Journal of Circuits, Systems and Computers

The world is witnessing a sudden shift in the paradigm of technology moving from centralized to decentralized approach. Centralized approach leads to single point of failure if any fault occurs and hence a whole system comes to rest. Hence, a decentralized approach like Multi-Agent System is trending now-a-days. A MAS is a collection of a number software entities (agents) working together in pursuit of specified tasks. This paper presents a comprehensive review on various aspects of multi-agent system. The paper explains the basic concepts of MAS with various ways it has been defined in literature. A comparison has been made on the standards to be followed for applying MAS. Classification of MAS architecture has been investigated and compared. Application of MAS in various areas of optimization technique, software platform and real-time simulation are listed in the paper. The paper draws attentions toward benefits and limitations of using MAS based on the survey done. Finally, after visualizing the wide scope of research in the field of MAS, an attempt has been made to identify future research avenues.

This paper presents a solar photovoltaic (SPV) interfaced shunt active power filter (APF), which is certainly one of the utmost effective custom power devices, which mitigates the long duration current harmonics and compensates the reactive power. The shunt APF consists of the parallel connected voltage source inverter (VSI) and storage capacitor which is connected in the DC link. The compensation ability of the APF is mainly inspired by the control technique which is used to estimate the reference source current signal. Furthermore, the controller chooses the number of devices required and measurement practices; thus, it determines the corresponding costs. The fuzzy logic controller (FLC)-based second order generalized integrator (SOGI) is employed to estimate the reference source current of the shunt APF. The presented control scheme does not require voltage associated information and sensors, because it utilizes the details concerning the VSI and load currents. The shunt APF uses the solar photovoltaic (SPV) system with an auxiliary energy storage unit to deliver the required active power to the electric grid and affords the uninterrupted compensation. The performance analysis has been carried out with different load and voltage conditions through the simulation by using the MATLAB/Simulink. The experimental prototype was developed to confirm the usefulness of the PV integrated shunt APF with FLC-based SOGI control scheme.

Aiming at optimizing polymer flooding, we establish an optimal control model of polymer flooding, which has an objective function of the net present value (NPV) involving the effect of polymer injection. An improved Monte Carlo gradient approximation (MCGA) algorithm, based on the idea of the ensemble-based optimization (EnOpt) scheme to solve the problem of strongly fluctuating perturbation gradients, is proposed by introducing the covariance matrix of the control vectors to filter and smooth the searching direction. A synthetic heterogeneous reservoir model is built to test the performance of the algorithms including the improved MCGA, standard MCGA and finite difference stochastic approximation (FDSA) algorithm. For the results, the improved MCGA gets closer to the optimal NPV of FDSA than the standard algorithm, and shows the high efficiency of saving calculation time compared with the FDSA. The value of NPV increases more than 20% for the improved algorithm, and the optimal production rates, injection rates, polymer concentrations, polymer slug sizes are obtained simultaneously. This paper subsequently discusses the influence of different time step sizes and oil prices. It can be concluded that moderate step size and relatively low oil price are applicable. Finally, an actual block application of the improved MCGA shows a 11.3% increase of NPV and a 6.5% increase of field oil production total (FOPT), showing the feasibility in optimizing real reservoirs.

In this paper, we consider a cooperative mobile-to-mobile wireless short-term Weibull fading channel. The source mobile station communicates with the destination via a relay. The channel is considered to be interference-limited, and the interference is present at both relay and the destination. The exact closed-form expressions for the destination mobile station signal-to-interference ratio probability density function and the cumulative distribution function are derived. Approximate numerically efficient closed-form expressions for the level crossing rate and the average fade duration are also derived, using Laplace approximation for a three-fold integral. The influence of the fading channel parameters on the mentioned statistical measures is investigated. The theoretical results are verified by the Monte-Carlo simulation.

Artefacts which are present in electrocardiogram (ECG) recordings distort detection of life-threatening arrhythmias such as ventricular tachycardia and ventricular fibrillation. The method examines single ECG lead and exploits time domain signal parameters for real-time detection of severe cardiac arrhythmias. The method is dedicated to implementation in mobile ECG telemetry systems, which are designed by using low-power microcontrollers, operating more than a week on a single battery charge. The method has been validated on publicly available databases and the results are presented. We verified our method on ECG signals obtained without pre-selection meaning that the noisy intervals were not omitted from signal analysis.

Due to the absence of commercially available fractional-order capacitors and inductors, their implementation can be performed using fractional-order differentiators and integrators, respectively, combined with a voltage-to-current conversion stage. The transfer function of fractional-order differentiators and integrators can be approximated through the utilization of appropriate integer-order transfer functions. In order to achieve that, the Continued Fraction Expansion as well as the Oustaloup’s approximations can be utilized. The accuracy, in terms of magnitude and phase response, of transfer functions of differentiators/integrators derived through the employment of the aforementioned approximations, is very important factor for achieving high performance approximation of the fractional-order elements. A comparative study of the accuracy offered by the Continued Fraction Expansion and the Oustaloup’s approximation is performed in this paper. As a next step, the corresponding implementations of the emulators of the fractional-order elements, derived using fundamental active cells such as operational amplifiers, operational transconductance amplifiers, current conveyors, and current feedback operational amplifiers realized in commercially available discrete-component IC form, are compared in terms of the most important performance characteristics. The most suitable of them are further compared using the OrCAD PSpice software.

As the only nonlinear operation, masked S-box is the core to resist differential power attack (DPA) for advanced encryption standard (AES) cipher chips. In order to suit for the resource-constrained applications, a compact masked S-box based on composite field is proposed in this paper. Firstly, the architecture of masked S-box is designed with composite field masking method. Secondly, four masked S-boxes based on GF ((2${}^4{)}^2)$, which are based on four basis methods with the optimal coefficient and the corresponding optimal root, are implemented and optimized by the delay-aware common subexpression elimination (DACSE) algorithm. Finally, experimental results show that, while maintaining the DPA-resistance performance, our best masked S-box achieves better area performance with the fastest speed compared with the existing works. Therefore, our masked S-box is suitable for resource-constrained applications with fast speed requirements.

The paper presents a computationally efficient method for modeling and simulating distributed systems with lossy transmission line (TL) including multiconductor ones, by a less conventional method. The method is devised based on 1D and 2D Laplace transforms, which facilitates the possibility of incorporating fractional-order elements and frequency-dependent parameters. This process is made possible due to the development of effective numerical inverse Laplace transforms (NILTs) of one and two variables, 1D NILT and 2D NILT. In the paper, it is shown that in high frequency operating systems, the frequency dependencies of the system ought to be included in the model. Additionally, it is shown that incorporating fractional-order elements in the modeling of the distributed parameter systems compensates for losses along the wires, provides higher degrees of flexibility for optimization and produces more accurate and authentic modelling of such systems. The simulations are performed in the Matlab environment and are effectively algorithmized.

Compared with the traditional copper material, carbon nanotube (CNT) has been identified as one of the most potential materials for interconnects in nanometer regime due to higher performance. However, for CNT interconnects, most of the researches focus on voltage-mode signaling (VMS) scheme, whereas current-mode signaling scheme (CMS) is meagerly investigated. The paper proposes an equivalent circuit model of two-line coupled single-walled CNT bundle interconnects, which is applicable to both CMS and VMS schemes. In addition, the model takes capacitive and inductive crosstalk into consideration. In CMS and VMS interconnects, the performance of victim line in the time domain is studied according to decoupling technique and ABCD parameter matrix approach at local, intermediate and global levels, respectively. The influence of aggressor line on victim line is discussed because of dynamic crosstalk and functional crosstalk. Furthermore, the paper comparatively analyzes the performance advantage between CMS interconnects and VMS interconnects. The results show that CMS interconnects have lower output voltage swing and propagation delay than VMS interconnects in the same condition. In terms of noise, CMS scheme has higher advantage for lesser noise peak, noise width and noise area. Moreover, it is found that the results obtained by ABCD parameter matrix approach have great consistency with Advanced Design System simulation results.

This paper describes a multi-scale feature integration framework using angular pattern (AP), binary AP (BAP) and sequential backward selection (SBS) algorithms. These angular descriptors are represented by multi-scale features from which the best subsets of the scales are chosen using five-fold cross-validation technique along with SBS algorithm for efficient image retrieval. The SBS algorithm reduces the dimensionality of feature space which in turn reduces the matching time complexity. The extracted AP and BAP features are represented in histograms and are compared by the Chi-square distance metric. The experimental analysis is performed on the MPEG-7 CE-1 Part-B dataset images to demonstrate the effectiveness of multi-scale feature integration using SBS algorithm. The image retrieval performance of this framework is compared with state-of-the-art shape descriptors. Being multi-scale global shape descriptors, the proposed framework captures complete information about the shape and are invariant to scaling and rotation transformations.

The proposed reversible data hiding technique is the extension of Peng et al.’s technique [F. Peng, X. Li and B. Yang, Improved PVO-based reversible data hiding, Digit. Signal Process. 25 (2014) 255–265]. In this technique, a cover image is segmented into nonoverlapping blocks of equal size. Each block is sorted in ascending order and then differences are calculated on the basis of locations of its largest and second largest pixel values. Negative predicted differences are utilized to create empty spaces which further enhance the embedding capacity of the proposed technique. Also, the already sorted blocks are used to enhance the visual quality of marked images as pixels of these blocks are more correlated than the unsorted pixels of the block. Experimental results show the effectiveness of the proposed technique.

This study demonstrates the utilization of model reference adaptive control (MRAC) for closed-loop fractional-order PID (FOPID) control of a magnetic levitation (ML) system. Design specifications of ML transportation systems require robust performance in the presence of environmental disturbances. Numerical and experimental results demonstrate that incorporation of MRAC and FOPID control can improve the disturbance rejection control performance of ML systems. The proposed multiloop MRAC–FOPID control structure is composed of two hierarchical loops which are working in conjunction to improve robust control performance of the system in case of disturbances and faults. In this multiloop approach, an inner loop performs a regular closed-loop FOPID control, and the outer loop performs MRAC based on Massachusetts Institute of Technology (MIT) rule. These loops are integrated by means of the input-shaping technique and therefore no modification of any parameter of the existing closed-loop control system is necessary. This property provides a straightforward design solution that allows for independent design of each loop. To implement FOPID control of the ML system, a retuning technique is used which allows transforming an existing PID control loop into an FOPID control loop. This paper presents the simulation and experimental results and discusses possible contributions of multiloop MRAC–FOPID structure to disturbance rejection control of the ML system.

Internet protocol (IP)-based mobile systems are ushering new and faster technologies in wireless mobile networking. Therefore, the expectations from these network services with respect to data transfer rate and quality of service (QoS) are high. As such, meeting these requirements is the recent trend in modern wireless technologies. An important aspect regarding such improvements is the modification of handoff schemes between different networks. In this paper, we are focusing on the recent trends based on seamless handoff scheme in heterogeneous networks such as worldwide interoperability for microwave access (WiMAX) and long term evolution (LTE). The development of the session initiation protocol (SIP) Prior-INVITE scheme is an improvement on the earlier used SIP Re-INVITE method, which comes a long way in decreasing the average handoff delay. The performance analysis using software simulation on account of various parameters, such as handoff delay, cost of signaling and packet loss rate are accomplished in this work. The performance analysis demonstrates that the proposed scheme outperforms the ordinary cross-layer scheme and noncross-layer scheme in a vertical handover scenario.

The paper proposed a high efficiency boost converter with constant voltage (CV) and constant current (CC) modes. The selection of CV or CC working mode is based on the requirement, and the transient time from CV to CC mode is 230$\mu$s. The boost converter is particularly for the use of Li-ion battery portable devices. High efficiency is obtained by sleep/burst mode under light load and pulse width modulation (PWM) mode under heavy load. The quiescent current of the whole chip can be down to 6$\mu$A when the converter enters the standby mode. The converter has been made of 0.35$\mu$m complementary metal-oxide semiconductor (CMOS) process. Experimental results show that the peak efficiency is 98.2% at a 1.5A output current and a 4.2V input voltage.

Continuous query in location-based services may reveal the attribute information of the user obliviously, and an adversary may utilize the attribute as background knowledge to correlate the real locations and to generate location trajectory. Thus, the adversary can obtain the personal privacy of the user. In order to cope with this problem, several algorithms had been proposed. However, these algorithms were mainly designed for snapshot query and failed to provide privacy protection service for continuous query. As a matter of fact, continuous anonymous regions can also be used as the trajectory of regions and one can obtain the real location trajectory through calibration. In addition, other algorithms designed for continuous query may also utilize a longer running time to achieve the attribute anonymity and affect the balance of quality of service and personal privacy. Therefore, in order to cope with the above two problems, this paper provides a PSO anonymization, short for particle swarm optimization anonymization algorithm. This algorithm utilizes the particle swarm optimization clustering algorithm to accelerate the process of finding similar attributes in attribute generalization. Furthermore, this algorithm also utilizes the randomly chosen anonymous cells to further generalize the anonymous region, so that it can provide better privacy protection and better service quality. At last, this paper utilizes security analysis and experimental verification to further verify the effectiveness and efficiency of both the level of privacy protection and algorithm execution.

Nowadays, countermeasures against side-channel attack (SCA) have become necessary in hardware security. And the need for supporting multiple crypto algorithms on a chip is increasing. We propose a reconfigurable crypto coprocessor, which not only supports multiple crypto algorithms, but also provides multiple effective SCA countermeasures of SPA, DPA and EMA, by making use of its own reconfigurable features other than using extra resources. The countermeasure methods include several global and encryption flow related countermeasures, which can also be reconfigured along with the circuit function. This coprocessor is a coarse-grained reconfigurable architecture composed of several reconfigurable modules, such as logic arithmetic, shift, modular ADD/Substrate, permutation, S-box and modular multiplication units, all of which are reconfigurable. This reconfigurable cryptographic coprocessor is integrated into a system-on chip with a 32-bit CPU and fabricated in 0.18 m CMOS process with 1.8V supply and 100 MHz maximum frequency. Experimental results show that it can successfully resist SPA and DPA with one million power traces. As for EMA, if we use full countermeasures, it can resist EMA with up to 1.2 million electromagnetic traces without revealing the right subkey. Thus, this reconfigurable coprocessor can provide a good solution for both supporting multiple algorithms and providing SCA resistance, with no frequency influence, neglectable area overhead and small power overhead.

By advances in cloud storage systems, users have access to the data saved in the cloud and can manipulate the data without limitation of time and place. As the data owner no longer possesses data physically, he is required to ensure the integrity of the data stored in the cloud with the public key given by public key infrastructure (PKI). Thus the security of PKI and certificates are essential. However, there are numerous security risks in the traditional PKI and it is complex to administer the certificates. Certificateless public key cryptography is used in this paper to solve these problems. We also use elliptic curve group to reduce computation overhead. In this paper, we design a certificateless public verification mechanism to check the integrity of data outsourced in the cloud and we further extend it to support a multiuser group by batch verification. Specifically, a public verifier who replaces the data owner to check the integrity in the proposed scheme does not require to manage any certificates during the verification process. Meanwhile, a verifier is not required to download the entire file for integrity checking. Theoretical analyses verify the security of our scheme and experimental results show its efficiency.