Advances in Fractal and Fractional Dynamics

A special issue of Fractal and Fractional (ISSN 2504-3110).

Deadline for manuscript submissions: 31 December 2026 | Viewed by 1339

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Engineering School (DEIM), University of Tuscia, Largo dell'Università, 01100 Viterbo, Italy
Interests: computational methods; mathematical physics; nonlinear systems
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Special Issue Information

Dear Colleagues,

The rapid development of fractional calculus, fractal geometry, and their applications across physics, engineering, biology, and data science has led to a growing need for interdisciplinary platforms that integrate theory, computation, and real-world modeling. Fractals and fractional calculus have changed the way we model and understand complexity across mathematics, physics, engineering, and beyond. Fractals offer a powerful framework for describing irregular, self-similar structures found in nature and science, while fractional calculus provides a flexible and accurate tool for modeling memory effects, anomalous diffusion, and nonlocal phenomena. Together, they have provided fundamental theories and inspired innovative applications in diverse fields, ranging from fluid dynamics and materials science to finance, biology, and data analysis. Their impact continues to expand in the study of complex systems in the modern scientific landscape.

The 1st Online Conference on Fractal and Fractional Calculus aims to bring together leading researchers and emerging scholars to present recent advances in the following:

  • Fractional differential equations
  • Fractal-based modeling of complex systems
  • Nonlocal and memory-dependent processes
  • Applications in physics, engineering, finance, and life sciences

This Special Issue has been organized together with the 1st International Conference on Fractal and Fractional (IOCFF 2026) (13–15 April 2026, Online); hence, participants in IOCFF 2026 are especially welcome to submit their contributions. However, we will accept contributions from all authors, not just conference participants, for the Special Issue.

This Special Issue will focus on cutting-edge developments in fractal and fractional methodologies, both theoretical and applied. Core themes include, but are not limited to, the following:

Theoretical Developments

  • Fractional operators (Caputo, Riemann–Liouville, etc.)
  • Fractal measures and geometries
  • Nonlocal and memory kernels
  • Stability, well-posedness, and asymptotic analysis
  • Ordinary and partial fractional differential problems

Computational and Numerical Methods

  • Numerical schemes for fractional ordinary and PDEs
  • Spectral and pseudo-spectral methods
  • Machine learning approaches for fractional systems
  • Numerical and analytical methods
  • Soliton theory

Applications

  • Waves, diffusion and anomalous transport solitons
  • Complex networks and logistics systems
  • Finance and stochastic processes
  • Biological systems and epidemiology
  • Signal processing and control theory

Emerging Topics

  • Fractional stochastic dynamics (e.g., Fokker–Planck frameworks)
  • Fractal and fractional system-information theory
  • Multiscale modeling with fractal constraints
  • Data-driven fractional modeling

Prof. Dr. Carlo Cattani
Prof. Dr. Haci Mehmet Baskonus
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-anonymized peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fractal and Fractional is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • fractional calculus
  • fractal geometry
  • nonlocal dynamics
  • complex systems
  • fractional PDEs
  • stochastic processes
  • multiscale modeling
  • network dynamics

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Published Papers (4 papers)

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Research

15 pages, 2791 KB  
Article
Fractal, Entropy, and Chaotic Dynamics in the Oil–Macroeconomy Relation: A Fractal Regression Method
by Melike E. Bildirici, Merve Colak and Ayse Demirhan
Fractal Fract. 2026, 10(7), 467; https://doi.org/10.3390/fractalfract10070467 (registering DOI) - 10 Jul 2026
Viewed by 96
Abstract
Macroeconomic systems are increasingly characterized by fractal structures, entropy-generating processes, and chaotic dynamics that challenge the assumptions of traditional regression methods. The presence of self-similarity, fractal structure, and sensitivity to initial conditions suggests that macroeconomic variables evolve through complex interactions that cannot be [...] Read more.
Macroeconomic systems are increasingly characterized by fractal structures, entropy-generating processes, and chaotic dynamics that challenge the assumptions of traditional regression methods. The presence of self-similarity, fractal structure, and sensitivity to initial conditions suggests that macroeconomic variables evolve through complex interactions that cannot be adequately explained within an equilibrium-based method. Motivated by this perspective, this paper tested the relationships between oil prices and macroeconomic variables in the United States over the period of 1960–2024 using a suggested fractal regression approach. The analysis proceeds in two stages. In the first stage, fractal, entropy, and chaotic structures of the variables were analyzed by employing entropy measures, Lyapunov exponents, attractor diagnostics by including Lorenz and Julia structures, and tests for fractal dimension: d parameter (GPH) and d parameter (Phillips), and long range dependendeceLo’s Modified R/S, and Hurst–Mandelbrot R/S. Our results explored evidence of fractal structure, complexity, and chaotic behavior within the selected macroeconomic series by indicating the presence of nonlinear dynamics and sensitivity to initial conditions. In the second stage, a proposed chaotic–fractal-based regression model is employed to explore the transmission mechanism of oil price to economic growth, inflation, and unemployment. By directly incorporating Lyapunov and fractal-based measures into the regression method, the model captured nonlinear interactions that are overlooked by traditional methods. The results revealed that oil price shocks generate chaotic and fractal effects across macroeconomic variables and that these effects vary according to the degree of chaotic divergence embedded in the system. Overall, the results suggested the interconnected roles of fractality, entropy, and chaos in shaping macroeconomic dynamics and showed the importance of chaos- and fractal-based modeling methods for understanding the economic consequences of energy shocks and their policy implications. Full article
(This article belongs to the Special Issue Advances in Fractal and Fractional Dynamics)
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27 pages, 14085 KB  
Article
A Fractional-Order Proportional-Derivative Controller Synthesis for String-Stable Cooperative Adaptive Cruise Control Systems
by Dorukhan Astekin, Mumin Tolga Emirler and Erkin Dinçmen
Fractal Fract. 2026, 10(7), 465; https://doi.org/10.3390/fractalfract10070465 - 10 Jul 2026
Viewed by 110
Abstract
Cooperative adaptive cruise control (CACC), as an extension of adaptive cruise control (ACC), is an intelligent transportation approach for connected and automated vehicles. By using vehicle-to-vehicle information, CACC improves longitudinal tracking performance, traffic throughput, and string-stable platoon behavior. However, controller tuning remains sensitive [...] Read more.
Cooperative adaptive cruise control (CACC), as an extension of adaptive cruise control (ACC), is an intelligent transportation approach for connected and automated vehicles. By using vehicle-to-vehicle information, CACC improves longitudinal tracking performance, traffic throughput, and string-stable platoon behavior. However, controller tuning remains sensitive to vehicle-dynamics parameters, spacing-policy selection, fractional-order dynamics, and communication delay. This paper presents an analytical parameter-space-based fractional-order PD (FOPD) controller synthesis framework for string-stable CACC systems. For the constant-time headway spacing policy, the controller parameters are investigated in the (kp,kd,μ) parameter space, where the fractional differentiation order μ is considered as an additional design variable. To obtain the feasible stabilizing regions, the fractional-order characteristic equation is evaluated on the imaginary axis, and the delay-dependent stability boundaries are derived through a frequency-domain boundary-locus formulation. The stabilizing gain regions are constructed through the complex-root boundary (CRB), real-root boundary (RRB), and infinite-root boundary (IRB), which provide an interpretable graphical basis for controller-gain and fractional-order selection. In addition, the effect of the headway time on the admissible stability region is examined jointly with the fractional order. The proposed structure is implemented with a feedforward controller that uses the acceleration information of the preceding vehicle under a predecessor-vehicle-following communication topology. The selected fractional-order CACC (FO-CACC) controller is validated in an eight-vehicle platoon simulation environment and compared with integer-order ACC (IO-ACC), fractional-order ACC (FO-ACC), and integer-order CACC (IO-CACC) configurations. The results show that the proposed parameter-space approach enables systematic FOPD tuning and that the selected FO-CACC controller satisfies the frequency-domain string-stability requirement while maintaining smooth time-domain responses in position, velocity, acceleration, headway time, spacing error, and control input. Additional simulations under the New European Driving Cycle (NEDC) and the FTP-75 (Federal Test Procedure 1975) driving cycles further indicate that the proposed FO-CACC structure maintains accurate spacing regulation and bounded acceleration behavior under standard drive-cycle conditions. Overall, the results indicate that the fractional-order parameter provides an effective design freedom for improving string-stable cooperative platoon performance. Full article
(This article belongs to the Special Issue Advances in Fractal and Fractional Dynamics)
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17 pages, 586 KB  
Article
Stability Analysis of Nonlinear Caputo Cotangent Fractional Systems
by Ibtehal Alazman, Lakhlifa Sadek, Ahmad Shafee and Khalid Aldawsari
Fractal Fract. 2026, 10(6), 395; https://doi.org/10.3390/fractalfract10060395 - 9 Jun 2026
Viewed by 204
Abstract
In this manuscript, the stability characteristics of nonlinear nonautonomous dynamical systems with the newly defined Caputo cotangent fractional derivative (CCFD) are discussed. Conditions that guarantee stability and asymptotic stability of the system are developed through comparison methods for CCFD systems using Lyapunov functions. [...] Read more.
In this manuscript, the stability characteristics of nonlinear nonautonomous dynamical systems with the newly defined Caputo cotangent fractional derivative (CCFD) are discussed. Conditions that guarantee stability and asymptotic stability of the system are developed through comparison methods for CCFD systems using Lyapunov functions. A quadratic inequality for the CCFD and a sign lemma are established as key analytical tools. The additional parameter r2 continuously recovers the classical Caputo derivative at r2=1 and introduces an exponential attenuation mechanism when 0<r2<1. Analytical examples and a reproducible numerical trajectory study illustrate the influence of r2 on the decay of solutions. The results extend classical Lyapunov stability theory to a broader class of nonlinear fractional systems and suggest modeling opportunities in systems where power-law memory and exponential attenuation coexist. Full article
(This article belongs to the Special Issue Advances in Fractal and Fractional Dynamics)
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34 pages, 3467 KB  
Article
Statistical and Dynamical Analysis of Hidden Attractors in the Fractional Glukhovsky–Dolzhansky System
by Salem Mubarak Alzahrani, Ghaliah Alhamzi, Mona Bin-Asfour, Mansoor Alsulami, Khdija O. Taha, Najat Almutairi and Sayed Saber
Fractal Fract. 2026, 10(6), 377; https://doi.org/10.3390/fractalfract10060377 - 30 May 2026
Viewed by 280
Abstract
This study investigates the reliable numerical analysis of chaotic dynamics in the Glukhovsky–Dolzhansky system, which models convective fluid motion in a rotating ellipsoidal cavity. Hidden and self-excited attractors are localized using the numerical continuation method (NCM), Pyragas time-delayed feedback control, and Leonov’s analytical [...] Read more.
This study investigates the reliable numerical analysis of chaotic dynamics in the Glukhovsky–Dolzhansky system, which models convective fluid motion in a rotating ellipsoidal cavity. Hidden and self-excited attractors are localized using the numerical continuation method (NCM), Pyragas time-delayed feedback control, and Leonov’s analytical dimension formula following global stability loss. A critical assessment of Lyapunov exponents and Lyapunov dimensions in a finite-time setting shows that positive values over long but finite intervals may incorrectly indicate sustained chaos due to transient effects and shadowing breakdown. Furthermore, we demonstrate that the fractional order γ plays a bidirectional control role: it induces chaotic behavior at ρ=5 for γ<0.94 and suppresses chaos at ρ=15 for γ<0.93. The multifractal spectrum and correlation dimension are used to quantify attractor complexity, where transient chaos exhibits a broader spectrum (Δα0.67) compared to sustained chaos (Δα0.48). Monte Carlo simulations, Sobol sensitivity analysis, Kaplan–Meier survival analysis, and bootstrap-based hypothesis testing confirm the robustness of the results. Overall, the findings provide a unified framework for analyzing hidden attractors, transient chaos, and fractional-order effects in nonlinear fluid dynamical systems. Full article
(This article belongs to the Special Issue Advances in Fractal and Fractional Dynamics)
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