George Angelov

Prof. George Angelov

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 January 2019
Verified
Book Chapter
Open access
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GAGeorge Angelov
George Angelov
DNDimitar Petrov Nikolakov
Dimitar Petrov Nikolakov
IRIvelina Nikolaeva Ruskova
Ivelina Nikolaeva Ruskova
EGElitsa Gieva
Elitsa Gieva
MSMaria Liubomirova Spasova
Maria Liubomirova Spasova
This chapter presents an overview of many wearable devices of different types that have been proven in medical and home environments as being helpful in Quality of Life enhancement of elder adults. The recent advances in electronics and microelectronics allow the development of low-cost devices that are widely used by many people as monitoring tools for well-being or preventive purposes. Remote healthcare monitoring, which is based on non-invasive and wearable sensors, actuators and modern communication and information technologies offers efficient solutions that allows people to live in their comfortable home environment, being somehow protected. Furthermore, the expensive healthcare facilities are getting free to be used for intensive care patients as the preventive measures are getting at home. The remote systems can monitor very important physiological parameters of the patients in real time, observe health conditions, assessing them, and most important, provide feedback. Sensors are used in electronics medical and non-medical equipment and convert various forms of vital signs into electrical signals. Sensors can be used for life-supporting implants, preventive measures, long-term monitoring of disabled or ill patients. Healthcare organizations like insurance companies need real-time, reliable, and accurate diagnostic results provided by sensor systems that can be monitored remotely, whether the patient is in a hospital, clinic, or at home.

3 November 2019 in Journal of Electrical and Computer Engineering
Verified
Journal Article
Open access
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GAGeorge Angelov
George Angelov
DNDimitar Nikolov Nikolov
Dimitar Nikolov Nikolov
MHMarin H. Hristov
Marin H. Hristov
This paper presents a comprehensive outlook for the current technology status and the prospective upcoming advancements. VLSI scaling trends and technology advancements in the context of sub-10-nm technologies are reviewed as well as the associated device modeling approaches and compact models of transistor structures are considered. As technology goes into the nanometer regime, semiconductor devices are confronting numerous short-channel effects. Bulk CMOS technology is developing and innovating to overcome these constraints by introduction of (i) new technologies and new materials and (ii) new transistor architectures. Technology boosters such as high-k/metal-gate technologies, ultra-thin-body SOI, Ge-on-insulator (GOI), AIII–BV semiconductors, and band-engineered transistor (SiGe or Strained Si-channel) with high-carrier-mobility channels are examined. Nonclassical device structures such as novel multiple-gate transistor structures including multiple-gate field-effect transistors, FD-SOI MOSFETs, CNTFETs, and SETs are examined as possible successors of conventional CMOS devices and FinFETs. Special attention is devoted to gate-all-around FETs and, respectively, nanowire and nanosheet FETs as forthcoming mainstream replacements of FinFET. In view of that, compact modeling of bulk CMOS transistors and multiple-gate transistors are considered as well as BSIM and PSP multiple-gate models, FD-SOI MOSFETs, CNTFET, and SET modeling are reviewed.

3 July 2020 in Materials
Verified
Journal Article
Open access
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Dorian MinkovDorian Minkov
Dorian Minkov
GAGeorge Angelov
George Angelov
RNRadi Nestorov
Radi Nestorov
ANAleksey Nezhdanov
Aleksey Nezhdanov
DUDmitry Usanov
Dmitry Usanov
AMAleksandr Mashin
Aleksandr Mashin
Three AsxTe100−x films with different x and dissimilar average thickness d ¯ are characterized mainly from one interference transmittance spectrum T(λ = 300 to 3000 nm) of such film on a substrate based on the advanced optimizing envelope method (AOEM). A simple dual transformation of T(λ) is proposed and used for increasing the accuracy of computation of its envelopes T+(λ) and T−(λ) accounting for the significant glass substrate absorption especially for λ > 2500 nm. The refractive index n(λ) of As40Te60 and As98Te2 films is determined with a relative error 300 nm on a substrate, compared to all the other methods for characterization of such films only from T(λ).

1 May 2018
Verified
Conference Paper
Closed access
GAGeorge Angelov
George Angelov
MAMiroslav Andreev
Miroslav Andreev
Nikolay HinovNikolay Hinov
Nikolay Hinov
Electric vehicles (EVs) require fast-charging station networks to allow owners to rapidly charge the battery on long-distance drives. Fast-charging electric vehicles requires a sufficiently powerful connection to the electric power grid. Modeling and control of the process for charging the electric vehicles (EVs) are reviewed. The modeling approach and the models describing the system components are detailed. A model of a charging system for EVs and plug-in electric vehicles (PHEVs) is developed.

28 October 2022 in Energies
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Journal Article
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Bogdan GilevBogdan Gilev
Bogdan Gilev
MAMiroslav Andreev
Miroslav Andreev
Nikolay HinovNikolay Hinov
Nikolay Hinov
GAGeorge Angelov
George Angelov
In recent years, micro turbine technology has become a continuously reliable and viable distributed generation system. The application of distributed energy power generation sources, such as micro gas turbines (MGT), to charge electric vehicles offers numerous technical, economical benefits, and opportunities. MGT are considered as they are smaller than conventional heavy-duty gas turbines. They also are capable of accepting and operating with different fossil fuels in the range of low–high pressure levels as well as co-generation opportunities. The MGT could provide the fast and reliable output power guaranteed and needed for grid stability. This paper provides a mathematical representation, modelling, and simulation of a low-cost fast charging station based on a micro gas turbine and a super capacitor forming altogether a power generation system suitable for use especially as energy source in fast charging stations and dynamic power systems. All the micro gas turbine’s parameters are estimated according to available performance and operational data. The proposed system generates up to 30 kW output power assuming that it operates with natural gas. The developed model of the system is simulated in the environment of MATLAB/Simulink. Each part of the micro turbine generation system is represented by a mathematical model. On the basis of the developed model of the system, the minimum value of the supercapacitor was determined, which ensures the charging schedule of a selected electric vehicle.

19 August 2021 in Materials
Verified
Journal Article
Open access
PDF file
Dorian MinkovDorian Minkov
Dorian Minkov
Emilio MarquezEmilio Marquez
Emilio Marquez
GAGeorge Angelov
George Angelov
GGGavril Gavrilov
Gavril Gavrilov
Susana FernándezSusana Fernández
Susana Fernández
ESElias Saugar
Elias Saugar
Three means are investigated for further increasing the accuracy of the characterization of a thin film on a substrate, from the transmittance spectrum T(λ) of the specimen, based on the envelope method. Firstly, it is demonstrated that the accuracy of characterization, of the average film thickness d¯ and the thickness non-uniformity ∆d over the illuminated area, increases, employing a simple dual transformation utilizing the product T(λ)xs(λ), where Tsm(λ) is the smoothed spectrum of T(λ) and xs(λ) is the substrate absorbance. Secondly, an approach is proposed for selecting an interval of wavelengths, so that using envelope points only from this interval provides the most accurate characterization of d¯ and ∆d, as this approach is applicable no matter whether the substrate is transparent or non-transparent. Thirdly, the refractive index n(λ) and the extinction coefficient k(λ) are computed, employing curve fitting by polynomials of the optimized degree of 1/λ, instead of by previously used either polynomial of the optimized degree of λ or a two-term exponential of λ. An algorithm is developed, applying these three means, and implemented, to characterize a-Si and As98Te2 thin films. Record high accuracy within 0.1% is achieved in the computation of d¯ and n(λ) of these films.