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The roads we travel daily are exposed to several energy sources (mechanical load, solar radiation, heat, air movement, etc.), which can be exploited to make common systems and apparatus for roadways (i.e., lighting, video surveillance, and traffic monitoring systems) energetically autonomous. For decades, research groups have developed many technologies able to scavenge energy from the said sources related to roadways: electromagnetism, piezoelectric and triboelectric harvesters for the cars' stress and vibrations, photovoltaic modules for sunlight, thermoelectric solutions and pyroelectric materials for heat and wind turbines optimized for low-speed winds, such as the ones produced by moving vehicles. Thus, this paper explores the existing technologies for scavenging energy from sources available on roadways, both natural and related to vehicular transit. At first, to contextualize them within the application scenario, the available energy sources and transduction mechanisms were identified and described, arguing the main requirements that must be considered for developing harvesters applicable on roadways. Afterward, an overview of energy harvesting solutions presented in the scientific literature to recover energy from roadways is introduced, classifying them according to the transduction method (i.e., piezoelectric, triboelectric, electromagnetic, photovoltaic, etc.) and proposed system architecture. Later, a survey of commercial systems available on the market for scavenging energy from roadways is introduced, focusing on their architecture, performance, and installation methods. Lastly, comparative analyses are offered for each device category (i.e., scientific works and commercial products), providing insights to identify the most promising solutions and technologies for developing future self-sustainable smart roads. [ABSTRACT FROM AUTHOR]

A new fractional-order chaotic system with no equilibria is presented. The proposed system can be considered elegant in the sense given by Sprott (2010), since the corresponding systemequations contain very fewterms and the systemparameters have a minimum of digits. The chaotic dynamics are analyzed using the predictor-corrector algorithm when the fractional-order of the derivative is 0.98. Finally, the presence of chaos is validated by applying different numerical methods. [ABSTRACT FROM AUTHOR]

This paper deals with chaos synchronization for a class of fractional-order systems characterized by one nonlinearity. In particular, an observer-based approach is illustrated, which presents two remarkable features: (i) it provides an exact analytical solution of the fractional error dynamics, written in terms of Mittag-Leffler function; (ii) it enables synchronization to be achieved using a scalar transmitted signal. Finally, a synchronization example based on fractional Chua's system is illustrated, with the aim to show the capabilities of the developed approach. [ABSTRACT FROM AUTHOR]

This paper illustrates a reliable binary test for detecting the presence of chaos in nonlinear systems described by fractional-order differential equations. The method, which is inspired by the technique proposed in [Gottwald & Melbourne, 2004] for integer-order differential equations, does not require phase space reconstruction of the fractional system. It consists of obtaining the data series, constructing a random walk-type process and studying how the variance of the random walk scales with time. In order to show the capabilities of the approach, the test is successfully applied to three well-known dynamical systems, i.e. fractional Chua, Chen and Lorenz systems. [ABSTRACT FROM AUTHOR]

By using a time-domain approach, this paper analyzes the chaotic dynamics of the fractional-order system obtained by coupling two fractional Lorenz systems. The work exploits the Adomian decomposition method (ADM), shows that the proposed fractional system with order as low as 2.88 exhibits a novel four-wing chaotic attractor. The existence of chaos is also confirmed by the application of the "0-1 test" for chaos. Finally, an analysis of the system equilibria is conducted, which shows that the fractional-order four-wing attractor is truly the counterpart of the recently introduced integer-order four-wing attractor. [ABSTRACT FROM AUTHOR]

This Letter analyzes the hyperchaotic dynamics of the fractional-order Rössler system from a time-domain point of view. The approach exploits the Adomian decomposition method (ADM), which generates series solution of the fractional differential equations. A remarkable finding of the Letter is that hyperchaos occurs in the fractional Rössler system with order as low as 3.12. This represents the lowest order reported in literature for any hyperchaotic system studied so far. [ABSTRACT FROM AUTHOR]

This tutorial investigates bifurcation and chaos in the fractional-order Chen system from the time-domain point of view. The objective is achieved using the Adomian decomposition method, which allows the solution of the fractional differential equations to be written in closed form. By taking advantage of the capabilities given by the decomposition method, the paper illustrates two remarkable findings: (i) chaos exists in the fractional Chen system with order as low as 0.24, which represents the smallest value ever reported in literature for any chaotic system studied so far; (ii) it is feasible to show the occurrence of pitchfork bifurcations and period-doubling routes to chaos in the fractional Chen system, by virtue of a systematic time-domain analysis of its dynamics. [ABSTRACT FROM AUTHOR]

In this tutorial the chaotic behavior of the fractional-order Chua's circuit is investigated from the time-domain point of view. The objective is achieved using the Adomian decomposition method, which enables the solution of the fractional differential equations to be found in closed form. By exploiting the capabilities offered by the decomposition method, the paper presents two remarkable findings. The first result is that a novel bifurcation parameter is identified, that is, the fractional-order q of the derivative. The second result is that chaos exists in the fractional Chua's circuit with order q = 1.05, which is the lowest order reported in literature for such circuits. Finally, a reliable and efficient binary test for chaos (called "0–1 test") is utilized to detect the presence of chaotic attractors in the system dynamics. [ABSTRACT FROM AUTHOR]

This paper focuses on the numerical study of chaotic dynamics via the Adomian decomposition method. The approach, which provides series solutions of the system equations, is first applied to Chua's circuit and Chua's oscillator, both with cubic nonlinearity. Successively, the method is utilized for obtaining hyperchaotic multiscroll attractors in a ring of three Chua's circuits, where the smooth nonlinearities are Hermite interpolating polynomials. The reported examples show that the approach presents two main features, i.e. the system nonlinearity is preserved and the chaotic solution is provided in a closed form. [ABSTRACT FROM AUTHOR]

In this Letter, attention is focused on the dynamics of a second-order nonlinear circuit driven by two sinusoidal signals. The early results reported herein show that the application of signals with slightly different frequencies enables the phenomenon of chaotic beats to be generated. In particular, the beats dynamics are analyzed both in time-domain and state-space, confirming the chaotic behavior of the proposed circuit. [ABSTRACT FROM AUTHOR]

This paper illustrates the recent phenomenon of chaotic beats in a modified version of Chua's circuit, driven by two sinusoidal inputs with slightly different frequencies. In order to satisfy the constraints imposed by the beats dynamics, a novel implementation of the voltage-controlled characteristic of the Chua diode is proposed. By using Pspice simulator, the behavior of the designed circuit is analyzed both in time-domain and state-space, confirming the chaotic nature of the phenomenon and the effectiveness of the approach. [ABSTRACT FROM AUTHOR]

This paper focuses on the dynamics of coupled Chua's circuits driven by two sinusoidal signals. In particular, it is shown that the application of signals with slightly different frequencies enables the new phenomenon of chaotic beats to be generated. Finally, the application of signals with equal frequencies is discussed, with the aim of understanding the formation of beats in nonlinear circuits. [ABSTRACT FROM AUTHOR]

This paper presents an approach for generating new hyperchaotic attractors in a ring of Chua's circuits. By taking a closed chain of three circuits and exploiting sine functions as nonlinearities, the proposed technique enables 3D-scroll attractors to be generated. In particular, the paper shows that 3D-scroll dynamics can be designed by modifying six parameters related to the circuit nonlinearities. [ABSTRACT FROM AUTHOR]

In this paper an approach for generating new hyperchaotic attractors from coupled Chua circuits is proposed. The technique, which exploits sine functions as nonlinearities, enables n×m-scroll attractors to be generated. In particular, it is shown that n×m-scroll dynamics can be easily designed by modifying four parameters related to the circuit nonlinearities. Simulation results are reported to illustrate the capability of the proposed approach. [ABSTRACT FROM AUTHOR]

Presents a novel framework for synchronizing hyperchaotic systems with one or several nonlinearities. Technique using observer design and time-division multiplexing of the transmitted signal; Requirement of only a scalar signal for achieving hyperchaos synchronization.

In this paper identical and generalized synchronization and the complex dynamics of hyperchaotic circuits are exploited for designing reliable cryptosystems. Since chaotic additive masking, chaotic switching and chaotic parameter modulation methods can have a low degree of security, an attempt to overcome this drawback is made by utilizing hyperchaotic circuits which make available several chaotic signals. Some of these signals are used to properly synchronize the encrypter and the decrypter in an identical and generalized way. Other chaotic signals are considered for encrypting and decrypting the information messages by means of a multishift cipher scheme. The approach is applied to a communication system constituted by an encrypter and a decrypter each consisting of two coupled Chua's circuits, unidirectionally coupled with two coupled Chua's oscillators. Simulation results are reported to show the performance of the suggested cryptosystem. [ABSTRACT FROM AUTHOR]

This paper describes the development and characterization of a smart garment for monitoring the environmental and biophysical parameters of the user wearing it; the wearable application is focused on the control to workers' conditions in dangerous workplaces in order to prevent or reduce the consequences of accidents. The smart jacket includes flexible solar panels, thermoelectric generators and flexible piezoelectric harvesters to scavenge energy from the human body, thus ensuring the energy autonomy of the employed sensors and electronic boards. The hardware and firmware optimization allowed the correct interfacing of the heart rate and SpO2 sensor, accelerometers, temperature and electrochemical gas sensors with a modified Arduino Pro mini board. The latter stores and processes the sensor data and, in the event of abnormal parameters, sends an alarm to a cloud database, allowing company managers to check them via a web app. The characterization of the harvesting subsection has shown that ≈ 265 mW maximum power can be obtained in a real scenario, whereas the power consumption due to the acquisition, processing and BLE data transmission functions determined that a 10 mAh/day charge is required to ensure the device's proper operation. By charging a 380 mAh Lipo battery in a few hours by means of the harvesting system, an energy autonomy of 23 days was obtained, in the absence of any further energy contribution. [ABSTRACT FROM AUTHOR]

This paper aims to study the limitations and performances of the main energy storage devices commonly used in energy harvesting applications, namely super-capacitors (SC) and lithium polymer (LiPo) batteries. The self-discharge phenomenon is the main limitation to the employment of SCs to store energy for a long time, thus reducing efficiency and autonomy of the energy harvesting system. Therefore, the analysis of self-discharge trends was carried out for three different models of commercial SCs, describing the phenomenon in terms of self-discharge rate and internal resistance. In addition, physical interpretations concerning the self-discharge mechanism based on the experimental data are provided, thus explaining the two super-imposed phenomena featured by distinct time constants. Afterwards, the dependence of self-discharge phenomenon from the charging time duration (namely, SCs charged at 5 V and then kept under charge for one or five hours) was analyzed; by comparing the voltage drop during the self-discharge process, a self-discharge reduction for longer charging durations was obtained and the physical interpretation provided (at best −6.8% after 24 h and −13.4% after 120 h). Finally, self-discharge trends of two commercial 380 mAh LiPo batteries (model LW 752035) were acquired and analyzed; the obtained results show an open circuit voltage reduction of only 0.59% in the first 24 h and just 1.43% after 124 h. [ABSTRACT FROM AUTHOR]

In this paper, the nonlinear dynamics of the biological system modeled by the fractional incommensurate order Van der Pol equations are investigated. The stability of the proposed fractional non-autonomous system is analyzed by varying both the fractional order derivative and system parameters. Moreover, very interesting phenomena such as symmetry, multi-stability and coexistence of attractors are discovered in the considered biological system. Numerical simulations are performed by considering the Caputo fractional derivative and results are reported by means of bifurcation diagrams, computation of the largest Lyapunov exponent, phase portraits in 2D and 3D projections. [ABSTRACT FROM AUTHOR]

This study describes an innovative complete car control system against children abandonment in unattended vehicles. Even if systems of this kind are already available in the automotive market, other solutions are currently object of intense researches by several important Research and Development centres or under patent procedure. In this study, a description of the technologies already adopted in the currently used car control systems and in those that are in research and testing phase too is provided. Then, it will be introduced to the proposed control system, which enables to improve all the described systems by providing innovative technologies and functionalities. The proposed system implements a microwave motion sensor, two infrared sensors, a carbon dioxide sensor, a temperature/humidity sensor, a vocal detector and a micro‐camera. These acquisition devices are connected to a microcontroller board that is able to combine all acquired data for detecting the alarm scenario and consequently acting some warning procedures: alarm short message service transmission with vehicle Global Positioning System position, vehicle's horn activation and/or car windows lowering. Thanks to such a wide set of sensors, the system can correlate the acquired information in order to ensure a good detection capability in every condition in which it can operate. [ABSTRACT FROM AUTHOR]

Technological innovation has increased the global demand for electrical power and energy. Accordingly, energy harvesting has become a research area of primary interest for the scientific community and companies because it constitutes a sustainable way to collect energy from various sources. In particular, kinetic energy generated from human walking or vehicle movements on smart energy floors represents a promising research topic. This paper aims to analyze the state-of-art of smart energy harvesting floors to determine the best solution to feed a lighting system and charging columns. In particular, the fundamentals of the main harvesting mechanisms applicable in this field (i.e., piezoelectric, electromagnetic, triboelectric, and relative hybrids) are discussed. Moreover, an overview of scientific works related to energy harvesting floors is presented, focusing on the architectures of the developed tiles, the transduction mechanism, and the output performances. Finally, a survey of the commercial energy harvesting floors proposed by companies and startups is reported. From the carried-out analysis, we concluded that the piezoelectric transduction mechanism represents the optimal solution for designing smart energy floors, given their compactness, high efficiency, and absence of moving parts. [ABSTRACT FROM AUTHOR]