A Novel Artificial Intelligence Based Timing Synchronization Scheme for Smart Grid Applications

The smart grid control applications necessitate real-time communication systems with time efficiency for real-time monitoring, measurement, and control. Time-efficient communication systems should have the ability to function in severe propagation conditions in smart grid applications. The data/packet communications need to be maintained by synchronized timing and reliability through equally considering the signal deterioration occurrences, which are propagation delay, phase errors and channel conditions. Phase synchronization plays a vital part in the digital smart grid to get precise and real-time control measurement information. IEEE C37.118 and IEC 61850 had implemented for the synchronization communication to measure as well as control the smart grid applications. Both IEEE C37.118 and IEC 61850 experienced a huge propagation and packet delays due to synchronization precision issues. Because of these delays and errors, measurement and monitoring of the smart grid application in real-time is not accurate. Therefore, it has been investigated that the time synchronization in real-time is a critical challenge in smart grid applications, and for this issue, other errors raised consequently. The existing communication systems are designed with the phasor measurement unit (PMU) along with communication protocol IEEE C37.118 and uses the GPS timestamps as the reference clock stamps. The absence of GPS increases the clock offsets, which surely can hamper the synchronization process and the full control measurement system that can be imprecise. Therefore, to reduce this clock offsets, a new algorithm is needed which may consider any alternative reference timestamps rather than GPS. The revolutionary Artificial Intelligence (AI) enables the industrial revolution to provide a significant performance to engineering solutions. Therefore, this article proposed the AI-based Synchronization scheme to mitigate smart grid timing issues. The backpropagation neural network is applied as the AI method that employs the timing estimations and error corrections for the precise performances. The novel AIFS scheme is considered the radio communication functionalities in order to connect the external timing server. The performance of the proposed AIFS scheme is evaluated using a MATLAB-based simulation approach. Simulation results show that the proposed scheme performs better than the existing system.

     

Efficient Photomodulation of Visible Eu(III) and Invisible Yb(III) Luminescences using DTE Photochromic Ligands for Optical Encryption

This work describes a class of complex combining three dithienylethene units and a lanthanide ion used as an optical system displaying a double encryption method: i) a colorful code, drawn and erased under UV and visible irradiations respectively, due to coloration and discoloration of the photochromic entities, and ii) a concomitant gradual disappearance and progressive restoration of the associated lanthanide ion luminescence triggered with the same stimuli. The innovation of the system stems from the emission color tunability, i.e., with either a lanthanide ion emitting only in the visible range (Eu³⁺) or with another lanthanide ion emitting only in the near infrared (NIR) range (Yb³⁺), therefore observable, or not, to the naked eye. This system is the very first one to achieve efficient repeatable modulation of pure NIR luminescence on photochemical command. Furthermore, it is proven to be highly efficient when embedded in a PDMS polymer opening real opportunities for practical applications as anti‐counterfeiting.     

Design and Analysis of a Channel Assignment Scheme for CDMA/TDMA Mobile Networks

In this paper, a channel assignment scheme is proposed for use in CDMA/TDMA mobile networks carrying voice and data traffic. In each cell, three types of calls are assumed to compete for access to the limited number of available channels by the cell: new voice calls, handoff voice calls, and data calls. The scheme uses the movable boundary concept in both the code and time domains in order to guarantee the quality of service (QoS) requirements of each type. A traditional Markov analysis method is employed to evaluate the performance of the proposed scheme. Measures, namely, the new call blocking probability, the handoff call forced termination probability, the data call loss probability, the expected number of handoff and the handoff link maintenance probability are obtained from the analysis. The numerical results, which are validated by simulation, indicate that the scheme helps meet the QoS requirements of the different call types.     

Optimal Resource Allocation in Heterogeneous MIMO Cognitive Radio Networks

The optimal resource allocation in MIMO cognitive radio networks with heterogeneous secondary users, centralized and distributed users, is investigated in this work. The core aim of this work is to study the joint problems of transmission time and power allocation in a MIMO cognitive radio scenario. The optimization objective is to maximize the total capacity of the secondary users (SUs) with the constraint of fairness. At first, the joint problems of transmission time and power allocation for centralized SUs in uplink is optimized. Afterwards, for the heterogeneous case with both the centralized and distributed secondary users, the resource allocation problem is formulated and an iterative power water-filling scheme is proposed to achieve the optimal resource allocation for both kinds of SUs. A dynamic optimal joint transmission time and power allocation scheme for heterogeneous cognitive radio networks is proposed. The simulation results illustrate the performance of the proposed scheme and its superiority over other power control schemes.     

Improving vehicular safety message delivery through the implementation of a cognitive vehicular network

The Wireless Access in Vehicular Environments (WAVE) protocol stack has been recently defined to enable vehicular communication on the Dedicated Short Range Communication (DSRC) frequencies. Some recent studies have demonstrated that the WAVE technology might not provide sufficient spectrum for reliable exchange of safety information over congested urban scenarios. In this paper, we address this issue, and present a novel cognitive network architecture in order to dynamically extend the Control Channel (CCH) used by vehicles to transmit safety-related information. To this aim, we propose a cooperative spectrum sensing scheme, through which vehicles can detect available spectrum resources on the 5.8 GHz ISM band along their path, and forward the data to a fixed infrastructure known as Road Side Units (RSUs). We design a novel Fuzzy-Logic based spectrum allocation algorithm, through which the RSUs infer the actual CCH contention conditions, and dynamically extend the CCH bandwidth in network congestion scenarios, by using the vacant frequencies detected by the sensing module. The simulation results reveal the effectiveness of our architecture in providing dynamic and scalable allocation of spectrum resources, and in increasing the performance of safety-related applications.     

A BIST-DFT technique for DC test of analog modules

Among test techniques for analog circuits, DC test is one of the simplest method for BIST application since easy to integrate test pattern generator and response analyzer are conceivable. Precisely, this paper presents such an investigation for a CMOS operational amplifier that is latter extended to active analog filters. Since the computation of fault coverage is still a controversy question for analog cells, we develop first an evaluation technique for optimizing the tolerance band of the measurements to test. Then, using some DFT solutions we derive single DC pattern and discuss the minimal number of points to test for the detection of defects. A response analyzer is integrated with a Built-in Voltage Sensor (BIVS) and provides directly a logic pass/fail test result. Finally, the extra circuitry introduced by this BIST technique for analog modules does not exceed 5% of the total silicon area of the circuit under test and detects most of the faults.     

The impact of metal-1 plasma processing-induced hot carrierinjection on the characteristics and reliability of n-MOSFETs

We report on plasma processing-induced damage to sub-half-micron n-MOSFETs that is invoked by potential differences between device terminals during metal-1 plasma processing. The damage mechanism is identified as hot carrier (HC) injection promoted by the layout of metal-1 interconnect. Using conventional and modified charge pumping techniques as well as transistor parameter measurements, we also investigate the impact of the damage on device reliability by applying Fowler-Nordheim (FN) and hot carrier stresses. The results show the severe impact of this damage on device reliability, which is attributed to trapping of positive charge at the drain edge that is enough to shorten the device channel     

Error rate for optimal follower tone-jamming

The performance of a countermeasure technique in the presence of the optimal follower multitone jammer is evaluated for frequency-hopped spread spectrum (FHSS) communications. It is shown that, with a certain probability, the optimal jammer will have dual tones in a frequency channel     

Capacity analysis of a TDMA-based slow-frequency-hopped cellularsystem

Time-division multiple access (TDMA)-based systems have been adopted as the first generation digital cellular standards in North America, Europe, and Japan. The increasing demand for capacity motivates the study of alternate systems and enhancements to the adopted TDMA standards. In particular, CDMA techniques using direct sequence and slow frequency hopping have been suggested. We analyze the capacity of a slow-frequency-hopped TDMA-based cellular system via calculation of the outage probability. Expressions for the outage probability as a function of voice activity, power control, and antenna diversity are provided for mobile-to-base transmission. These expressions are used to evaluate the system capacity (users/MHz/cell) based on simulating mobile locations within 37 hexagonal cells. The sensitivity to power control error, voice activity factor, and soft capacity of the system is investigated     

Point-matching method for reduction of anomalous radiation of log-periodic dipole array

A point matching method is developed for the evaluation of the performance of the log-periodic dipole antenna (LPDA. Based on this method, the anomalous behaviour of the LPDA is studied and found to be improved at an optimum spacing factor and by selecting a small dipole length to diameter ratio; that is, an LPDA, operating over a given frequency band, must possess an optimum dimension that gives a pattern with eliminated anomalous backlobe peaks.<>