Lykourgos Magafas

Lykourgos Magafas
International Hellenic University · Physics

Prof. L.Magafas

About

84
Publications
9,141
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474
Citations
Introduction
Lykourgos Magafas currently works at the Physics Department of International Hellenic University, Greece. His current project is 'Data analysis using non- linear dynamics'.

Publications

Publications (84)
Article
Full-text available
Intelligence service, in government and military operations, evaluates information on the strength, activities, and possible course of action of foreign countries or non-state actors. The term Open-Source Intelligence (OSINT) is used to collect, analyze and distribute the information collected through the analysis of data from publicly accessible s...
Article
Full-text available
In the last years, materializations of neuromorphic circuits based on nanophotonic arrangements have been proposed, which contain complete optical circuits, laser, photodetectors, photonic crystals, optical fibers, flat waveguides, and other passive optical elements of nanostructured materials, which eliminate the time of simultaneous processing of...
Article
Full-text available
In the last years, materializations of neuromorphic circuits based on nanophotonic arrangements have been proposed, which contain complete optical circuits, laser, photodetectors, photonic crystals, optical fibers, flat waveguides and other passive optical elements of nanostructured materials, which eliminate the time of simultaneous processing of...
Poster
Full-text available
According to the Brane-World scenario, the universe we perceive corresponds to an infinitely, positive tendency super-thin membrane. This membrane is immersed in a (4+n)-dimensional space-time (Bulk), with gravity being able to propagate to additional dimensions and spread gravitational interactions throughout the space. Explaining how the geometri...
Preprint
Full-text available
In the last years, materializations of neuromorphic circuits based on nanophotonic arrangements have been proposed, which contain complete optical circuits, laser, photodetectors, photonic crystals, optical fibers, flat waveguides, and other passive optical elements of nanostructured materials, which eliminate the time of simultaneous processing of...
Article
Full-text available
With the advent of the first pandemic wave of Severe Acute Respiratory Syndrome Coro-navirus-2 (SARS-CoV-2), the question arises as to whether the spread of the virus will be controlled by the application of preventive measures or will follow a different course, regardless of the pattern of spread already recorded. These conditions caused by the un...
Article
Full-text available
This paper proposes a new method for converting a time-series into a weighted graph (complex network), which builds on electrostatics in physics. The proposed method conceptualizes a time-series as a series of stationary, electrically charged particles, on which Coulomb-like forces can be computed. This allows generating electrostatic-like graphs a...
Article
The risk associated with nanomaterials has always been a concern for investors as a part of their decision-making process. To date, the concept of risk-return has never been used for nanomaterials. This paper takes a step in this direction by proposing a process based on the risk and returns of nanomaterials related to cancer treatment. The purpose...
Article
The dynamical evolution of multiscaling in financial time series is investigated using time-dependent Generalized Hurst Exponents (GHE), Hq, for various values of the parameter q. Using Hq, we introduce a new visual methodology to algorithmically detect critical changes in the scaling of the underlying complex time-series. The methodology involves...
Article
Full-text available
This paper proposes a method for examining chaotic structures in semiconductor or alloy voltage oscillation time-series, and focuses on the case of the TlInTe2 semiconductor. The available voltage time-series are characterized by instabilities in negative differential resistance in the current-voltage characteristic region, and are primarily chaoti...
Article
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This paper reviews health-related nanomaterial patents filed in the European Patent Office. Five-year patents were examined, with a focus on cancer treatment applications. The main objective of this work is to examine key patent information in order to cover trends and determine the technological subfields that are experiencing the highest growth i...
Preprint
The dynamical evolution of multiscaling in financial time series is investigated using time-dependent Generalized Hurst Exponents (GHE), $H_q$, for various values of the parameter $q$. Using $H_q$, we introduce a new visual methodology to algorithmically detect critical changes in the scaling of the underlying complex time-series. The methodology i...
Preprint
Full-text available
The global crisis caused by the COVID-19 pandemic, in conjunction with the economic consequences and the collapse of health systems, has raised serious concerns in Europe, which is the most affected continent by the pandemic since it recorded 2,388,694 cases and 190,091 deaths (39.6% of the worldwide total), of which 71.7% (136,238) are in the Unit...
Preprint
Full-text available
This paper proposes a new method for converting a time-series into a weighted graph (complex network), which builds on the electrostatic conceptualization originating from physics. The proposed method conceptualizes a time-series as a series of stationary, electrically charged particles, on which Coulomb-like forces can be computed. This allows gen...
Article
Full-text available
Within the complex framework of anti-COVID-19 health management, where the criteria of diagnostic testing, the availability of public-health resources and services, and the applied anti-COVID-19 policies vary between countries, the reliability and accuracy in the modeling of temporal spread can prove to be effective in the worldwide fight against t...
Article
Full-text available
Research background: The application of non-linear analysis and chaos theory modelling on financial time series in the discipline of Econophysics. Purpose of the article: The main aim of the article is to identify the deterministic chaotic behavior of stock prices with reference to Amazon using daily data from Nasdaq-100. Methods: The paper uses...
Article
Full-text available
Within the context of Greece promising a success story in the fight against the disease, this paper proposes a novel method for studying the evolution of the Greek COVID-19 infection curve in relation to the anti-COVID-19 policies applied to control the pandemic. Based on the ongoing spread of COVID-19 and the insufficient data for applying classic...
Article
Full-text available
Within the complex framework of anti-COVID-19 health management, where the criteria of diagnostic testing, the availability of public-health resources and services, and the applied anti-COVID-19 policies vary between countries, the reliability and the accuracy in the modeling of temporal spread can be proven effective in the worldwide fight against...
Preprint
Full-text available
Within the complex framework of anti-COVID-19 health management, where the criteria of diagnostic testing, the availability of public-health resources and services, and the applied anti-COVID-19 policies vary between countries, the reliability and the accuracy in the modeling of temporal spread can be proven effective in the worldwide fight against...
Preprint
Full-text available
Within the context that Greece promises a success story in the fight against the disease, this paper proposes a novel method to study the evolution of the Greek COVID-19 infection-curve in relation to the anti-COVID-19 policies applied to control the pandemic. Based on the ongoing spreading of COVID-19 and the insufficient data for applying classic...
Preprint
Timeseries produced by a idealized macroeconomic model are analyzed by means of conversion to complex networks by three different methods: the re-cursive graph method, the natural visibility graph method and the ordinal partition graph method. For several values of one of the model's control parameters yielding both fully chaotic time-series and in...
Article
Full-text available
One of the most promising techniques of recent research is adsorption. This technique attracts great attention in environmental technology, especially in the decontamination of water and wastewaters. A “hidden” point of the above is the cost of adsorbents. As can be easily observed in the literature, there is not any mention about the synthesis cos...
Article
Full-text available
The profile management of nanomaterials requires a complicated synergy between component function and shape, material, process, and costs. This study attempts to uncover these relationships by grouping nanomaterial profile components with matching characteristics using cluster analysis. The analysis resulted in the identification of 11 distinct clu...
Article
The work presented here is a paradigm of EconoPhysics, i.e. of research in the area of finance and economics by applying physical models, in this case chaos theory. A specific analysis of a macroeconomic model proposed by Vosvrda is presented. The Vosvrda model is an idealized macroeconomic model, combining the savings of households, Gross Domestic...
Article
Over the past 30 years, there have been significant advancements in the field of nanomaterials. The possibility to use them in applications such as cancer treatment is extremely promising; however, the toxicity of many nanomaterials as well as the high costs associated with their use is still a concern. This paper aims to study the connection betwe...
Article
Full-text available
This paper applies non-linear methods to analyze and predict the daily VIX index which is one of the most important stock indexes in the world. The aim of the analysis is to quantitatively show if the corresponding time series is a deterministic chaotic one and if one or more days ahead prediction can be achieved. The research employs Grassberger a...
Article
Full-text available
In the present work the development of a new, very low cost, simple to manufacture and use, optical sensing device for remote, on line detection of the type of fuels used in ships, is presented. The main goal of this optical sensing device is the on line detection of the fuel optical absorption that is used by the ship. The basic operating principl...
Article
Full-text available
In this paper a circuit (physical system), implementing a financial system with time-delayed feedbacks, is designed and studied. The simple form of this dynamical system, without any time-delayed feed, has been already investigated and was found to demonstrate both a periodic and chaotic behavior. By introducing the time-delayed feedback, according...
Article
Full-text available
In this report, a study of the electrical behavior for the Metal/a-SiC/poly-Si(n) structure, appears. Di�erent thicknesses of a-SiC:H thin lms are considered; in speci c the a-SiC:H layer thickness is varied between 100 Å up to 800 Å. The 2-D ATLAS advanced numerical simulator has been utilized in order to simulate the material's electrical behavio...
Article
Full-text available
In this report, a study of the electrical behavior for the Metal/a-SiC/poly-Si(n) structure, appears. Di�erent thicknesses of a-SiC:H thin lms are considered; in speci c the a-SiC:H layer thickness is varied between 100 Å up to 800 Å. The 2-D ATLAS advanced numerical simulator has been utilized in order to simulate the material's electrical behavio...
Article
Full-text available
In this study we present results of the evaluation of q - triplet of Tsallis non-extensive statistics concerning two time stock market time series, Standart & Poor's 500 (S & P) 500 and TVIX. The analysis of the results, support the hypothesis in which economic dynamics from physical point of view correspond to far from equilibrium spatial distribu...
Article
Full-text available
This paper applies non linear methods to analyze the weekly gold prices close index .The aim of the analysis is to quantitatively show if the corresponding time series is a deterministic chaotic one and its predictable. For this purpose the correlation and minimum embedding dimensions of the corresponding strange attractor are calculated. Also the...
Article
Full-text available
This paper applies non-linear methods to analyze and predict the daily open S&P index which is one of the most important stock index in the world. The aim of the analysis is to quantitatively show if the corresponding time series is a deterministic chaotic one and if one or more days ahead prediction can be achieved. These results make the present...
Article
Full-text available
This paper explores the use of chaos theory, as well as the neural networks, for predicting the Production of Total Industry in Greece. We have found that our data (from 1961 up to 2011) obey to the chaos theory. More specifically, the results from evaluation show that the minimum emending dimension is 4 suggesting chaos with a high dimensionality....
Chapter
Full-text available
In this paper the electrical behavior of the Al/a-SiC:H/c-Si(n) heterojunction for different values of density of gap states (N) in a-SiC:H, is simulated and studied. It is observed that as the density of gap states in a-SiC:H increases from 10− 15 cm− 3 to 10− 18 cm− 3 the I-V characteristics, in the forward bias, present a deviation from the typi...
Chapter
Full-text available
Inspired from the application of physics in economy (Econophysics) and society (Sociophysics), the authors introduce the term DemoscopoPhysics as the latest interdisciplinary research field that applies theories and methods originally developed by physicists in order to predict election results by using mainly Non Linear Dynamics (chaotic dynamics)...
Article
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This study gives a new methodological framework regarding the measuring of the contribution of some key-factors on the regional growth rate and forecasting the future development rates, based on Neural Network Models NN Models. It's a serious attempt to study the contribution of twelve key-factors to the change of the Regional Gross Domestic Produc...
Article
Full-text available
In this report the dynamic behaviour of a nonlinear finance chaotic system was modeled by an electronic circuit and its behaviour was studied by means of electronic circuit simulation tools. A recently new proposed finance system is used. For this reason, a totally different approach in the study of its dynamic behaviour by using the bifurcation di...
Article
Full-text available
To date, accounting and financial sciences have attempted to assess companies using financial ratios and other techniques that evaluate only the front office, without considering its impact to the environment. Recently, this assessment has been expanded to include new concepts, known as corporate social responsibility and social balance. These new...
Article
Full-text available
This empirical research paper examines the structural changes in Brazilian, Mexican, Korean, Turkish, South African and the US financial markets in a comparative perspective. Using daily returns of stock markets, exchange rates and CDS spreads, the transition probabilities and regime properties in the selected developing markets are estimated and c...
Article
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This paper sets out to apply concepts of non linear dynamics theory nai neural networks to the prediction of CDS index using Greek, Turkey, Russia, Brazil and China data. The research employs the method of false near neighbors in the time series analysis in order to estimate the minimum membedding dimensions of the corresponding strange attractor....
Article
The experimental study of intermittency in the phase error signal, in a PLL master–slave configuration, is reported. Both master and slave phase-locked loop topologies are implemented by well known commercial PLLs, directly coupled to one another. The chaotic phenomenon appears in the limit of the operating range of a widely known and used configur...
Article
Full-text available
In this paper we will be trying to cross predict a multivariate time series of a single transistor chaotic circuit using neural networks. For this purpose we investigate the influence of a number of first and second order near neighbors in predicting chaotic time series using a back propagation neural network. This influence is examined by changing...
Article
Full-text available
The experimental study of a secure chaotic synchronized communication system is presented. The synchronization betweentwo digital chaotic oscillators, serving as a transmitter-receiver scheme, is studied. The oscillators exhibit rich chaotic behaviorand are unidirectionally coupled, forming a master-slave topology. Both the input information signal...
Article
Full-text available
In this paper we use chaos theory to predict the Hellenic Euro election results in the form of time series for Hellenic political parties New Democracy (ND), Panhellenic Socialistic Movement (PASOK), Hellenic Communistic Party (KKE) , Coalition of the Radical Left (SYRIZA) and (Popular Orthodox Rally) LAOS, using the properties of the reconstructed...
Article
Full-text available
In this paper we use a new scientific field called “DemoscopoPhysics” based on chaos theory to predict the Hellenic Na-tional election results in the form of time series for Hellenic political parties, New Democracy (ND), Panhellenic Socialistic Movement (PASOK), Hellenic Communistic Party (KKE), Coalition of the Radical Left (SYRIZA) and (Popular...
Article
The nonlinear behaviour of an R–L-Varactor circuit, simulated by Multisim 7.0 at a driving frequency that is below the circuit resonance frequency, is reported and evaluated. A new high amplitude oscillation is observed and attributed to the emergence of a large diode junction capacitance. Increasing the driving signal amplitude, the circuit is led...
Article
The electromagnetic directivity effects of dielectrics in slab shape are studied. Applying asymptotic expansion of generalized Laplace integrals we find the radiated far field by simple or compound radiating sources, which are encaged into dielectric materials. From the corresponding time-averaged Poynting vector it is found that we can manage the...
Article
Full-text available
The aim of the present work is to study the optimization of the electrical and optical properties of a-SiC:H Schottky di-odes using thermal annealing process to a-SiC:H thin films in the range from 300oC up to 675oC. The films were depos-ited onto c-Si(n) using the rf sputtered method at three different hydrogen flow rates, 9sccm, 14sccm, and 20scc...
Article
Full-text available
In the present work optical sensors of the form Al/a-SiC:H/c-Si(n), for different thickness of a-SiC:H thin films are stud-ied. More specifically, a-SiC:H thin films were deposited by rf sputtering technique on c-Si(n) substrates for different thickness of the amorphous semiconductor and, subsequently, the samples were annealed in the temperature r...
Article
Zeros and periodicities of the reflection coefficient and the interface impedance as well as transient response of Transverse Magnetic (TM) plane waves are studied. The symmetry in a multilayered structure shows an interesting behavior regarding the zeros of the reflection coefficient. For simple layered structures analytical solutions for the zero...
Article
Full-text available
In this paper we present the chaotic state of a LED as a diode element in a non linear LRD. Multisim is used to simulate the circuit and show the presence of chaos. Time series analysis performed by the method proposed by Grasberger and Procaccia. The correlation and minimum embedding dimension ? and m respectively were calculated. Also the corresp...
Article
The optimization of optoelectronic properties of Al/a-SiC:H Schottky diodes grown as Al/a-SiC:H/c-Si(n) structures is studied by means of thermal annealing of a-SiC:H thin films. According to the spectral response of the Schottky diodes the measured quantum efficiency, ηmeasured, increases with increasing annealing temperature (400–600 °C), whereas...
Article
The electromagnetic response of a multi - layer half space by means of the ray analysis technique is presented. The influence of the thickness as well as of the electromagnetic constants of the dielectric layers on the reflection coefficient is studied, assuming both pure and lossy dielectrics. The zeros and the periodicities of the reflection coef...
Article
The forthcoming end of the fossil fuel era combined with the increase of energy consumption and with the dramatic expansion of the environmental problems, are leading our society to the one way use of the renewable sources of energy. Furthermore, attention has to be drawn on the energy saving and rational use. Full description of system selecting o...
Data
In this paper we study the effect of annealing process on the optical and electrical properties of the a-SiC:H thin films sputtered at three different hydrogen flow rates 9 sccm, 14 sccm and 20 sccm. Optical transmission measurements have shown that the optical band gap, Eg, is affected by thermal annealing when Ta>575 o C, due to emission of hydro...
Article
In the present work the dependence of electrical properties of a-SiC:H thin films on annealing temperature, Ta, has been extensively studied. From the measurements of dark dc electrical conductivity, σD, in the high temperature range (from 283 up to 493K), was found that the conductivity activation energy, Ea, is invariant for Ta⩽673K and equal to...
Article
Full-text available
In this paper, an extensive study of the transient optical response speed of silicon Bulk-Barrier Diodes (BBDs) is presented. This study is based on the simulation results obtained with a 2-D device simulator (S-PISCES and LUMINOUS). The influence of significant quantities, as the applied voltage, the incident light power and the light wavelength,...