Electronics — Open Access Journal

The knowledge of the electromagnetic constitutive properties of materials is crucial in many applications. Free-space methods are widely used for this purpose, despite their inherent practical difficulties. This paper describes an affordable free-space experimental setup for the characterization of flat samples in 1–6 GHz in a non-anechoic environment. The extracted properties are obtained from the calibrated Scattering Parameters, using a frequency-by-frequency solution or a multi-frequency reconstruction. For the first, we describe how the Time-Domain Gating can be implemented and used for filtering the signals. For the latter, a weighting factor is introduced to balance the reflection and transmission data, allowing one to have a more favorable configuration. The different role of transmission and reflection measurements on the achievable results is analyzed with regard to experimental uncertainties and different noise scenarios. Results from the two strategies are analyzed and compared. Good agreement between simulation, measurement and literature is obtained. According to the reported results for dielectric materials, there is no need of filtering the data by a Time-Domain Gating in case of the multi-frequency approach. Experimental results for Polymethylmethacrylate (PMMA) and Polytetrafluorethylene (PTFE) samples validate both the setup and the processing. Full article

The effects of ultraviolet irradiation on luminescent centres in bismuth-doped (BDF) and bismuth/erbium co-doped (BEDF) optical fibers were examined in this study. The fibers were fabricated by modified chemical vapor deposition combining with atomic layer deposition method. The fibers were exposed to irradiation from a 193 nm pulsed wave argon fluoride laser, and an 830 nm wavelength laser diode pump source was employed for excitation. The experimental results showed that, for the BDF, the transmission loss was slightly reduced and the luminescence intensity was increased at the bismuth-related active aluminum centre (BAC-Al). Then, for the BEDF, the transmission loss was increased a little and the luminescence intensity was also increased at the BAC-Al centre. However, the luminescence intensity was decreased at approximately 1420 nm of the bismuth-related active silica centre (BAC-Si) for all fiber samples. One possible formation mechanism for luminescence intensity changes was probably associated with the valence state transfer of bismuth ions. The other possible mechanism was that the ArF-driven two-photon process caused luminescence changes in BAC-Al and BAC-Si. It was very important to reveal nature of luminescence properties of Bi-doped and Bi/Er co-doped optical fiber. Full article

Recently, concurrent error detection enabled through invariant relationships between different wires in a circuit has been proposed. Because there are many such implications in a circuit, selection strategies have been developed to select the most valuable implications for inclusion in the checker hardware such that a sufficiently high probability of error detection ($P_{detection}$) is achieved. These algorithms, however, due to their heuristic nature cannot guarantee a lossless $P_{detection}$. In this paper, we develop a new input-aware implication selection algorithm with the help of ATPG which minimizes loss on $P_{detection}$. In our algorithm, the detectability of errors for each candidate implication is carefully evaluated using error prone vectors. The evaluation results are then utilized to select the most efficient candidates for achieving optimal $P_{detection}$. The experimental results on 15 representative combinatorial benchmark circuits from the MCNC benchmarks suite show that the implications selected from our algorithm achieve better $P_{detection}$ in comparison to the state of the art. The proposed method also offers better performance, up to 41.10%, in terms of the proposed impact-level metric, which is the ratio of achieved $P_{detection}$ to the implication count. Full article

The aim of this review paper is to discuss some of the advanced sampling techniques proposed in the last decade in the framework of planar near-field measurements, clarifying the theoretical basis of the different techniques, and showing the advantages in terms of number of measurements. Instead of discussing the details of the techniques, the attention is focused on their theoretical bases to give a gentle introduction to the techniques. For each sampling method, examples on a liner array are discussed to clarify the advantages and disadvantages of the method. Full article

This paper proposes a novel bilateral control design based on an estimated reaction force without a force sensor for a three-degree of freedom hydraulic servo system with master–slave manipulators. The proposed method is based upon sliding mode control with sliding perturbation observer (SMCSPO) using a bilateral control environment. The sliding perturbation observer (SPO) estimates the reaction force at the end effector and second link without using any sensors. The sliding mode control (SMC) is used as a bilateral controller for the robust position tracking and control of the slave device. A bilateral control strategy in a hydraulic servo system provides robust position and force tracking between master and slave. The difference between the reaction force of the slave produced by the effect of the remote environment and the operating force applied to the master by the operator is expressed in the target impedance model. The impedance model is applied to the master and allows the operator to feel the reaction force from the environment. This research experimentally verifies that the slave device can follow the trajectory of the master device using the proposed bilateral control strategy based on the estimated reaction force. This technique will be convenient for three or more degree of freedom (DOF) hydraulic servo systems used in dismantling nuclear power plants. It is worthy to mention that a camera is used for visual feedback on the safety of the environment and workspace. Full article

When applied to road vehicle electrification, inductive power transfer (IPT) technology has the potential to boost the transition from combustion engines to electric motors powered by a battery pack. This work focuses on the validation of a PSpice circuit model developed as a replica of a 2-kW IPT prototype with series-series compensation operating at 18.65 kHz. The laboratory prototype has the three stages commonly found in an IPT system: an inverter, controlled by the phase-shift technique, a coil coupling and a load. Simulations were run with the circuit model for three different distances between the two coils of the inductive coupling, all of which are of interest for practical chargers: 125, 150 and 175 mm. The validation approach was based on tuning the magnetic coupling factor for each distance and a set of ten load resistances, until the best match between the simulated and the experimental peak currents supplied by the inverter was found in each case. The coupling factors obtained from the simulation work are in good agreement with their experimental counterparts for the three distances, provided the duty cycle of the inverter output voltage is not too small. The circuit model developed is, therefore, able to reproduce the behavior of the laboratory prototype with sufficient accuracy over a wide range of distances between coils and loading conditions. Full article

DC-DC buck converters are widely used in portable applications because of their high power efficiency. However, their inherent fast switching releases electromagnetic emissions, making them prominent sources of electromagnetic interference (EMI). This paper proposes a voltage-controlled buck converter that reduces EMI by using a chaotic pulse-width modulation (PWM) technique based on a chaotic triangular ramp generator. The chaotic triangular ramp generator is constructed from a simple on-chip chaotic circuit linked with a symmetrically triangular ramp circuit. The proposed converter can thus operate in the chaotic mode reducing the EMI without requiring any EMI filters. Additionally, using the triangular ramp signal can relax the requirement for a large LC output filter in chaotic mode. The effectiveness of the proposed scheme was experimentally verified with a chaotic triangular ramp generator embedded in a voltage-mode controller buck converter using a 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) process. The measurement results from a prototype showed that the EMI improvement from the proposed scheme is approximately 14.53 dB at the fundamental switching frequency with respect to the standard fixed-frequency PWM reference case. Full article

This paper is concerned with a novel event-triggered sliding mode variable structure control (ESMC) scheme to achieve robust stabilization of memristive systems (MSs). First, a memory-based sliding surface, including the past and the current information of the system states, is introduced. Two switching gain matrices of such kinds of switching surfaces, which satisfy the guaranteed cost performance of the sliding reduced order dynamics, are achieved by employing linear matrix inequality techniques. Second, a sliding mode controller using an event-triggered mechanism is constructed to ensure that the trajectories of the uncertain MS slide towards the proposed memory-based switching hyperplane, and thus, the stabilization of entire MSs is reached. Finally, the effectiveness of the proposed results is demonstrated through simulations. Full article

Designing chaotic oscillators using complementary metal-oxide-semiconductor (CMOS) integrated circuit technology for generating multi-scroll attractors has been a challenge. That way, we introduce a current-mode piecewise-linear (PWL) function based on CMOS cells that allow programmable generation of 2–7-scroll chaotic attractors. The mathematical model of the chaotic oscillator designed herein has four coefficients and a PWL function, which can be varied to provide a high value of the maximum Lyapunov exponent. The coefficients are implemented electronically by designing operational transconductance amplifiers that allow programmability of their transconductances. Design simulations of the chaotic oscillator are provided for the $0.35\mathsf{\mu }$m CMOS technology. Post-layout and process–voltage–temperature (PVT) variation simulations demonstrate robustness of the multi-scroll chaotic attractors. Finally, we highlight the synchronization of two seven-scroll attractors in a master–slave topology by generalized Hamiltonian forms and observer approach. Simulation results show that the synchronized CMOS chaotic oscillators are robust to PVT variations and are suitable for chaotic secure communication applications. Full article

Multi-protocol label switching (MPLS) is a promising solution to implement high-speed internet protocol (IP) networks by reducing the layer number. To meet the increasing demand for data traffic, optical packet switching (OPS) is integrated under IP to provide high bandwidth to end users. Generalized MPLS (GMPLS) is perfectly compatible with the routing algorithm in IP/MPLS as it supports packet-switching functions. In this paper, we investigate the label stacking scenarios in GMPLS networks. In GMPLS, label stacking is done to reduce the node complexity by appending multiple labels to a single packet. Wavelength-division multiplexing (WDM) and optical code-division multiplexing (OCDM) signals have been widely used as identifying labels. As the labels can be permutated among the wavelengths or code dimensions, the structure of a label stack can be varied. However, studies on the relationship between label stacking scenarios and network performance are limited. To investigate this issue, we propose three label stacking models: sequential code distribution; sequential wavelength distribution, and random label distribution. The simulation results show that the sequential wavelength assignment, wherein the labels are uniformly distributed among the wavelengths, exhibits the best system performance in terms of the label-error rate (LER). Full article

Source anonymity in wireless sensor networks (WSNs) becomes a real concern in several applications such as tracking and monitoring. A global adversary that has sophisticated resources, high computation and full view of the network is an obvious threat to such applications. The network and applications need to be protected and secured to provide the expected outcome. Source anonymity is one of the fundamental WSNs security issues. It is all about preventing the adversary from reaching the origin by analyzing the traffic of the network. There are many methods to provide source anonymity, which is also known as Source Location Privacy (SLP). One of these methods is based on dummy packets. The basic notion is to inject the network with dummy packets to confuse the adversary about the location of the transmitting source node. This paper provides a survey of protocols for anonymity that use dummy packet injections. We discuss each technique from the point of their advantages and disadvantages. Further, We provide a comparison for the most promising techniques provided in the literature which use dummy packet injections. A comparison for the adversary assumptions and capabilities will be provided as well. Full article

In this paper, we present a comprehensive study of smart grid security against cyber-physical attacks on its distinct functional components. We discuss: (1) a function-based methodology to evaluate smart grid resilience against cyber-physical attacks; (2) a Bayesian Attack Graph for Smart Grid (BAGS) tool to compute the likelihood of the compromise of cyber components of the smart grid system; (3) risk analysis methodology, which combines the results of the function-based methodology and BAGS to quantify risk for each cyber component of the smart grid; and (4) efficient resource allocation in the smart grid cyber domain using reinforcement learning (extension of BAGS tool) to compute optimal policies about whether to perform vulnerability assessment or patch a cyber system of the smart grid whose vulnerability has already been discovered. The results and analysis of these approaches help power engineers to identify failures in advance from one system component to another, develop robust and more resilient power systems and improve situational awareness and the response of the system to cyber-physical attacks. This work sheds light on the interdependency between the cyber domain and power grid and demonstrates that the security of both worlds requires the utmost attention. We hope this work assists power engineers to protect the grid against future cyber-physical attacks. Full article

Single event double upsets (SEDUs) caused by charge sharing have been an important contributor to the soft error in integrated circuits. Most of the up-to-date double-upset (DU) tolerant latches suffer from high costs in terms of delay, power and area. In this paper, we propose a novel high-performance low-cost double-upset tolerant (HLDUT) latch. Simulation waveforms have validated the double-upset tolerance of the proposed latch. Besides, detailed comparisons demonstrate that our design saves 805.24% delay-power-area product (DPAP) on average compared with other considered up-to-date double-upset tolerant latches, which means the proposed latch is a promising candidate for future highly reliable low-cost applications. Full article

In this paper, we review recent advances in reverse engineering with an emphasis on FPGA devices and experimentally verified advantages and limitations of reverse engineering tools. The paper first introduces essential components for programming Xilinx FPGAs (Xilinx, San Jose, CA, USA), such as Xilinx Design Language (XDL), XDL Report (XDLRC), and bitstream. Then, reverse engineering tools (Debit, BIL, and Bit2ncd), which extract the bitstream from the external memory to the FPGA and utilize it to recover the netlist, are reviewed, and their limitations are discussed. This paper also covers supplementary tools (Rapidsmith) that can adjust the FPGA design flow to support reverse engineering. Finally, reverse engineering projects for non-Xilinx products, such as Lattice FPGAs (Icestorm) and Altera FPGAs (QUIP), are introduced to compare the reverse engineering capabilities by various commercial FPGA products. Full article

High-power plasma power supply is very useful for many industrial and medical applications. Plasma is generated artificially in the laboratory or industry by applying the electric or magnetic field. In this manuscript, we presented the simple 4T analog MOS control high voltage high frequency inverter circuit as a plasma power supply using modulation index technique. The presented plasma power supply operated at 25 kHz frequency and 10 kV peak to peak voltage. It generates a 0 V to 10 kV controllable electric field. The generated electric field is applied and produces plasma, which can be used for many industrial applications. A 10 kV to 5 kW plasma power supply has been practically developed based on the proposed topology and experimentally tested and, additionally, excellent output power conversion efficiency is achieved. From these results, the 4T analog MOS control high voltage high frequency (HVHF) plasma switching power supply is verified. Full article

The visual tracking algorithm based on discriminative correlation filter (DCF) has shown excellent performance in recent years, especially as the higher tracking speed meets the real-time requirement of object tracking. However, when the target is partially occluded, the traditional single discriminative correlation filter will not be able to effectively learn information reliability, resulting in tracker drift and even failure. To address this issue, this paper proposes a novel tracking-by-detection framework, which uses multiple discriminative correlation filters called discriminative correlation filter bank (DCFB), corresponding to different target sub-regions and global region patches to combine and optimize the final correlation output in the frequency domain. In tracking, the sub-region patches are zero-padded to the same size as the global target region, which can effectively avoid noise aliasing during correlation operation, thereby improving the robustness of the discriminative correlation filter. Considering that the sub-region target motion model is constrained by the global target region, adding the global region appearance model to our framework will completely preserve the intrinsic structure of the target, thus effectively utilizing the discriminative information of the visible sub-region to mitigate tracker drift when partial occlusion occurs. In addition, an adaptive scale estimation scheme is incorporated into our algorithm to make the tracker more robust against potential challenging attributes. The experimental results from the OTB-2015 and VOT-2015 datasets demonstrate that our method performs favorably compared with several state-of-the-art trackers. Full article

Adder is an important datapath unit of a general-purpose microprocessor or a digital signal processor. In the nanoelectronics era, the design of an adder that is modular and which can withstand variations in process, voltage and temperature are of interest. In this context, this article presents a new robust early output asynchronous block carry lookahead adder (BCLA) with redundant carry logic (BCLARC) that has a reduced power-cycle time product (PCTP) and is a low power design. The proposed asynchronous BCLARC is implemented using the delay-insensitive dual-rail code and adheres to the 4-phase return-to-zero (RTZ) and the 4-phase return-to-one (RTO) handshaking. Many existing asynchronous ripple-carry adders (RCAs), carry lookahead adders (CLAs) and carry select adders (CSLAs) were implemented alongside to perform a comparison based on a 32/28 nm complementary metal-oxide-semiconductor (CMOS) technology. The 32-bit addition was considered for an example. For implementation using the delay-insensitive dual-rail code and subject to the 4-phase RTZ handshaking (4-phase RTO handshaking), the proposed BCLARC which is robust and of early output type achieves: (i) 8% (5.7%) reduction in PCTP compared to the optimum RCA, (ii) 14.9% (15.5%) reduction in PCTP compared to the optimum BCLARC, and (iii) 26% (25.5%) reduction in PCTP compared to the optimum CSLA. Full article

Stepper motors are employed in a wide range of consumer and industrial applications. Their use is simple: a digital device generates pulse-bursts and a direction bit towards a power driver that produces the 2-phase currents feeding the motor windings. Despite its simplicity, this open-loop approach fails if the torque load exceeds the motor capacity, so the motor and driver should be oversized at the expense of efficiency and cost. Field-Oriented closed-loop Control (FOC) solves the problem, and the recent availability of low cost electronics devices like Digital Signal Processors, Field Programmable Gate Arrays (FPGA), or even Microcontrollers with dedicated peripherals, fostered the investigation and implementation of several variants of the FOC method. In this paper, a simple and economic FOC torque control method for hybrid stepper motors is presented. The load angle is corrected accordingly to the actual shaft position through pulse-bursts and direction commands issued towards a commercial stepper driver, which manages the 2-phase winding currents. Thanks to the FPGA implementation, the control loop updates the electrical position every 50 μs only, thus allowing a load angle accuracy of −1/100 rad for a rotor velocity up to 750 rev/min, as shown in the reported experiments. Full article