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1,456 results on '"Georgiev, A."'

1. Discovery of Amphoteric Fingerprints of Amino Acids With Field-Effect Transistors

Author

Naveen Kumar, Rakshita Pritam Singh Dhar, Janwa El Maiss, Vihar Georgiev, and Cesar Pascual Garcia

Subjects
Amino acids, fingerprints, Gouy-Chapman-Stern model, ISFET, polypeptides, site-binding model, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

When working with a few molecules, the existing protein sequencing technologies lack the single-site amino acid (AA) precision required to detect abnormalities that escape genome analysis. We offer a new method for identifying AAs and short polypeptides using the signal from the surface potential and capacitance obtained from Field Effect Transistor (FET) sensors. Using a combination of the Site-binding and Gouy-Chapman-Stern (GCS) models, we found the signatures of every single AA and polypeptides. These fingerprints are based on orthogonal features such as the proton dissociation constants of each AA’s charging sites, the dielectric constant, and the effective length.

Published
2024
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2. LoRaWAN Optimization for Voltage Monitoring

Author

Dmitriy Kim, Andrey Turlikov, Georgi Georgiev, and Tatyana Dedova

Subjects
ALOHA, distributed energy sources, LoRaWAN, optimization problem, photovoltaic, probabilistic approach, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

This study examines the challenges encountered when using wireless technologies based on random multiple access for voltage monitoring in low voltage (LV) electrical grids. The introduction of photovoltaic modules on the roofs of buildings creates the need to monitor the dynamics of the node voltages of the grid. We consider two related objects – an LV electrical grid and a communication network with devices in the nodes of the grid. The communication network carries out one-way transmission of monitoring data from the devices to the LV grid operator and is based on LoRaWAN technology. Transmission is carried out via a common data transmission medium. We presume that each message contains information about the node voltage. The messages from each node in the grid are sent to the grid operator at random time intervals and independently of each other. If the airtimes of messages from two or more nodes overlap, a collision occurs and none of the messages reach the operator. The operator has to monitor the random voltage behavior over time to avoid exceeding a certain level (an upper voltage limit). Under the specifics of the voltage random process, we study the problem of choosing parameters of message transmission to uniformly minimize the probability of such excess among all nodes. The work precisely formulates the optimization problem and proposes an algorithm for its solution for the particular case.

Published
2024
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3. 2023 EELS Field Tests at Athabasca Glacier as an Icy Moon Analogue Environment

Author

Paton, Michael, primary, Rieber, Richard, additional, Cruz, Sarah, additional, Gildner, Matt, additional, Abma, Chantelle, additional, Abma, Kevin, additional, Aghli, Sina, additional, Ambrose, Eric, additional, Archanian, Avak, additional, Bagshaw, Elizabeth A., additional, Baroco, Cathy, additional, Blackstock, Andrew, additional, Bowkett, Joseph, additional, Cable, Morgan L., additional, Cartaya, Eduardo, additional, Daddi, Guglielmo, additional, Drevinskas, Tomas, additional, Etheredge, Rachel, additional, Gall, Tom, additional, Gardner, Alex S., additional, Gavrilov, Peter, additional, Georgiev, Nikola, additional, Graham, Katie, additional, Hockman, Benjamin, additional, Jones, Bryson, additional, Linn, Scott, additional, Malaska, Michael J., additional, Marteau, Eloïse, additional, Maslen, Nick, additional, Melikyan, Hovhannes, additional, Nakka, Yashwanth Kumar, additional, Nelson, Jason, additional, Pazzini, Michele, additional, Peticco, Martin, additional, Prior-Jones, Michael, additional, Robinson, Matthew, additional, Roman, Christiahn, additional, Royce, Rob, additional, Ryan, Mary, additional, Shiraishi, Lori, additional, Stenner, Christian, additional, Strub, Marlin, additional, Swan, Robert Michael, additional, Swerdlow, Ben, additional, Thakker, Rohan, additional, Tosi, Luis Phillipe, additional, Tran, Tony, additional, Vaquero, Tiago Stegun, additional, Veismann, Marcel, additional, Wood, Tom, additional, Zade, Harshad, additional, and Ono, Masahiro, additional

Published
2024
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6. A General Framework for Depth Compression and Multi-Sensor Fusion in Asymmetric View-Plus-Depth 3D Representation

Author

Mihail Georgiev, Evgeny Belyaev, and Atanas Gotchev

Subjects
3D, 3-D depth, fusion, compression, super-pixel, time-of-flight, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

We present a general framework which can handle different processing stages of the three-dimensional (3D) scene representation referred to as “view-plus-depth” (V+Z). The main component of the framework is the relation between the depth map and the super-pixel segmentation of the color image. We propose a hierarchical super-pixel segmentation which keeps the same boundaries between hierarchical segmentation layers. Such segmentation allows for a corresponding depth segmentation, decimation and reconstruction with varying quality and is instrumental in tasks such as depth compression and 3D data fusion. For the latter we utilize a cross-modality reconstruction filter which is adaptive to the size of the refining super-pixel segments. We propose a novel depth encoding scheme, which includes specific arithmetic encoder and handles misalignment outliers. We demonstrate that our scheme is especially applicable for low bit-rate depth encoding and for fusing color and depth data, where the latter is noisy and with lower spatial resolution.

Published
2020
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7. Substrate Integrated Waveguide Bandpass Filtering With Fourier-Varying Via-Hole Walling

Author

Osama I. Hussein, Khair A. Al Shamaileh, Nihad I. Dib, Amir Nosrati, Said Abushamleh, Daniel G. Georgiev, and Vijay Kumar Devabhaktuni

Subjects
Bandpass filter (BPF), half-mode substrate integrated waveguide (HMSIW), SIW-to-microstrip transition, narrowband, rectangular waveguide, substrate integrated waveguide (SIW), Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

In this article, an optimization-driven methodology is proposed for the design of substrate integrated waveguide (SIW) bandpass filters (BPFs) with predefined passbands. The width between the metallic walls of via-holes is governed by a truncated Fourier series to achieve the desired filtering performance. The theory of rectangular waveguide is used to establish the optimization framework and obtain the series coefficients under predefined physical constraints. Two types of end-terminations are studied; specifically, with and without SIW-to-microstrip transitions. To validate the proposed methodology, two Ku-band BPF prototypes with 2.5% and 5.8% 15-dB fractional bandwidth (FBW) are designed, simulated, and measured. Furthermore, the half-mode SIW (HMSIW) concept is incorporated in one prototype to facilitate a miniaturized physical structure. Simulations and measurements are in close proximity with passband matching and transmission losses better than -15 dB and -2.5 dB, respectively. The proposed methodology allows for designing BPFs with predefined wideband or narrowband FBW by modifying the underlying physical constraints and optimization parameters. The resulting filters are planar, compact, and have wide stopband rejection. In addition, a derivation for the characteristic impedance of the SIW line is provided, which can be used to find the optimum SIW-to-microstrip transition without performing a parametric study.

Published
2020
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17. EELS: Towards Autonomous Mobility in Extreme Terrain with a Versatile Snake Robot with Resilience to Exteroception Failures

Author

Thakker, Rohan, primary, Paton, Michael, additional, Strub, Marlin P., additional, Swan, Michael, additional, Daddi, Guglielmo, additional, Royce, Rob, additional, Tosi, Phillipe, additional, Gildner, Matthew, additional, Vaquero, Tiago, additional, Veismann, Marcel, additional, Gavrilov, Peter, additional, Marteau, Eloise, additional, Bowkett, Joseph, additional, Loret, Daniel, additional, Nakka, Yashwanth, additional, Hockman, Benjamin, additional, Orekhov, Andrew, additional, Hasseler, Tristan, additional, Leake, Carl, additional, Nuernberger, Benjamin, additional, Proença, Pedro, additional, Reid, William, additional, Talbot, William, additional, Georgiev, Nikola, additional, Pailevanian, Torkom, additional, Archanian, Avak, additional, Ambrose, Eric, additional, Jasper, Jay, additional, Etheredge, Rachel, additional, Roman, Christiahn, additional, Levine, Dan, additional, Otsu, Kyohei, additional, Melikyan, Hovhannes, additional, Nash, Jeremy, additional, Rieber, Richard, additional, Carpenter, Kalind, additional, Jain, Abhinandan, additional, Shiraishi, Lori, additional, Pastor, Daniel, additional, Yearicks, Sarah, additional, Ingham, Michel, additional, Robinson, Matthew, additional, Agha, Ali, additional, Travers, Matthew, additional, Choset, Howie, additional, Burdick, Joel, additional, and Ono, Masahiro, additional

Published
2023
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29. Ultra-Fast High-Contrast Optical Modulation in Si Metasurfaces

Author

Trifonov, Anton A., primary, Kamali, Khosro Zangeneh, additional, Georgiev, Kaloyan, additional, Xu, Lei, additional, Crotti, Giulia, additional, Arregui Leon, Unai, additional, Rahmani, Mohsen, additional, Valle, Giuseppe Della, additional, Buchvarov, Ivan, additional, and Neshev, Dragomir, additional

Published
2023
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30. Simulation Study of Vertically Stacked Lateral Si Nanowires Transistors for 5-nm CMOS Applications

Author

Talib Al-Ameri, Vihar P. Georgiev, Fikru Adamu-Lema, and Asen Asenov

Subjects
Nanowire transistor, TCAD, Monte Carlo, vertically stacked, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

In this paper, we present a simulation study of vertically stacked lateral nanowires transistors (NWTs), which may have applications at 5-nm CMOS technology. Our simulation approach is based on a collection of simulation techniques to capture the complexity in such ultra-scaled devices. Initially, we used drift-diffusion methodology with activated Poisson-Schrodinger quantum corrections to accurately capture the quantum confinement in the cross-section of the device. Ensemble Monte Carlo simulations are used to accurately evaluate the drive current capturing the complexity of the carrier transport in the NWTs. We compared the current flow in single, double, and triple vertically stacked lateral NWTs with and without contact resistance. The results presented here suggest a consistent link between channel strain and device performance. Furthermore, we propose a device structure for the 5-nm CMOS technology node that meets the required industry scaling projection. We also consider the interplay between various sources of statistical variability and reliability in this paper.

Published
2017
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38. Contrast Enhanced Radiography with a Printed Model

Author

Georgiev, Tihomir, Dukov, Nikolay, Todorov, Todor, and Bliznakova, Kristina

Subjects
3D printed model, breast application, dual-energy subtraction algorithm
Abstract

Dual energy contrast-enhanced spectral mammography (CESM) technique has been introduced to overcome the standard mammography's performance on dense breasts. To enhance the visualization of the tumour, iodine contrast is used followed by an acquisition of images at low and high energies, which are then combined into a single image for additional information. This study used a model of a compressed breast made from clear resin with holes on the top. The holes were filled with iodine-based contrast and images with six different energies (50 kVp, 70 kVp, 80 kVp, 90 kVp, 100 kVp, 120 kVp) were obtained at a general purpose x-ray unit. Then, 15 subtraction images were calculated by performing a pixel by pixel subtraction of each possible image pair and the contrast was evaluated. The results indicated that the best contrast rates are achieved on 50 kVp and 70 kVp as low energy and 100 kVp and 120 kVp as high energy. The best contrast was evaluated for the pair 70–120 kVp.

Published
2022

44. Impact of the Figures of Merit (FoMs) definitions on the variability in nanowire TFET: NEGF simulation study

Author

Yunhe Guan, Vihar P. Georgiev, Asen Asenov, Feng Liang, and Haifeng Chen

Subjects
Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials
Abstract

In this article, we investigate the effect of variability in p-type nanowire tunnel FET (TFET) using quantum mechanical transport simulations. The simulations have been carried out using the Nano Electronics Simulation Software (NESS) from the University of Glasgow. Random discrete dopants (RDDs) and work-function variations (WFV) have been investigated in the simulations. Our statistical simulations reveal that key figures of merit (FoMs) such as the current variability generally decrease as the gate voltage decreases, the threshold voltage variability increases as the threshold current increases, and the dependences of these FoM variabilities on criteria become stronger with the switch characteristic ameliorated. Furthermore, it is interesting to find that the band offset in heterostructure can more or less alleviate the current variability, especially around the OFF-state.

Published
2022

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