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179 results on '"Stevens, Nobby"'

1. Enhancing RSS-Based Visible Light Positioning by Optimal Calibrating the LED Tilt and Gain

Author

Wu, Fan, Stevens, Nobby, De Strycker, Lieven, and Rottenberg, François

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

This paper presents an optimal calibration scheme and a weighted least squares (LS) localization algorithm for received signal strength (RSS) based visible light positioning (VLP) systems, focusing on the often overlooked impact of light emitting diode (LED) tilt. By optimally calibrating LED tilt and gain, we significantly enhance VLP localization accuracy. Our algorithm outperforms both machine learning Gaussian processes (GPs) and traditional multilateration techniques. Against GPs, it achieves improvements of 58% and 74% in the 50th and 99th percentiles, respectively. When compared to multilateration, it reduces the 50th percentile error from 7.4 cm to 3.2 cm and the 99th percentile error from 25.7 cm to 11 cm. We introduce a low-complexity estimator for tilt and gain that meets the Cramer-Rao lower bound (CRLB) for the mean squared error (MSE), emphasizing its precision and efficiency. Further, we elaborate on optimal calibration measurement placement and refine the observation model to include residual calibration errors, thereby improving localization performance. The weighted LS algorithm's effectiveness is validated through simulations and real-world data, consistently outperforming GPs and multilateration, across various training set sizes and reducing outlier errors. Our findings underscore the critical role of LED tilt calibration in advancing VLP system accuracy and contribute to a more precise model for indoor positioning technologies.

Published
2024

2. Techtile -- Open 6G R&D Testbed for Communication, Positioning, Sensing, WPT and Federated Learning

Author

Callebaut, Gilles, Van Mulders, Jarne, Ottoy, Geoffrey, Delabie, Daan, Cox, Bert, Stevens, Nobby, and Van der Perre, Liesbet

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

New concepts for next-generation wireless systems are being developed. It is expected that these 6G and beyond systems will incorporate more than only communication, but also sensing, positioning, (deep) edge computing, and other services. The discussed measurement facility and approach, named Techtile, is an open, both in design and operation, and unique testbed to evaluate these newly envisioned systems. Techtile is a multi-functional and versatile testbed, providing fine-grained distributed resources for new communication, positioning and sensing technologies. The facility enables experimental research on hyper-connected interactive environments and validation of new algorithms and topologies. The backbone connects 140~resource units equipped with edge computing devices, software-defined radios, sensors, and LED sources. By doing so, different network topologies and local-versus-central computing can be assessed. The introduced diversity of i) the technologies (e.g., RF, acoustics and light), ii) the distributed resources and iii) the interconnectivity allows exploring more degrees and new types of diversity, which can be investigated in this testbed., Comment: arXiv admin note: substantial text overlap with arXiv:2105.06740

Published
2022
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20. Europe and the Future for WPT : European Contributions to Wireless Power Transfer Technology

Author

Carvalho, Nuno Borges, Georgiadis, Apostolos, Costanzo, Alessandra, Stevens, Nobby, Kracek, Jan, Pessoa, Luís, Roselli, Luca, Dualibe, Fortunato, Schreurs, Dominique, Mutlu, Senol, Rogier, Hendrik, Visser, Huib, Takacs, Alexandru, Rocca, Paolo, Dimitriou, Antonis, Michalski, Jerzy, Raida, Zbynek, Tedjini, Smail, Joseph, Wout, Duroc, Yvan, Sahalos, John N., Bletsas, Aggelos, Samaras, Theodoros, Nikoletseas, Sotiris, Raptis, Theofanis P., Boaventura, Alírio, Collado, Ana, Trevisan, Riccardo, Minnaert, Ben, Svanda, Milan, Pereira, Mário, Mongiardo, Mauro, Popov, Grigory, Pan, Ning, Aubert, Herve, Viani, Federico, Siachalou, Stavroula, Kant, Przemyslaw, Andia, Gianfranco, Polycarpou, Anastasis C., Cruz, Pedro, Mastri, Franco, Mazanek, Milos, Santos, Hugo, Alimenti, Federico, García-Vázquez, Hugo, Pollin, Sofie, Poli, Lorenzo, Belo, Daniel, Masotti, Diego, Machac, Jan, Tavares, Vítor, Mezzanotte, Paolo, Ndungidi, Papy, Oliveri, Giacomo, Fernandes, Ricardo, Salgado, Henrique, Moeyaert, Véronique, Massa, Andrea, Gonçalves, Ricardo, Pinho, Pedro, Monti, Giuseppina, Tarricone, Luciano, Dionigi, Marco, Russer, Peter, Russer, Johannes, Carvalho, Nuno Borge, Georgiadis, Apostolo, Costanzo, Alessandra, Stevens, Nobby, Kracek, Jan, Pessoa, Luí, Roselli, Luca, Dualibe, Fortunato, Schreurs, Dominique, Mutlu, Senol, Rogier, Hendrik, Visser, Huib, Takacs, Alexandru, Rocca, Paolo, Dimitriou, Antoni, Michalski, Jerzy, Raida, Zbynek, Tedjini, Smail, Joseph, Wout, Duroc, Yvan, Sahalos, John N., Bletsas, Aggelo, Samaras, Theodoro, Nikoletseas, Sotiri, Raptis, Theofanis P., Boaventura, Alírio, Collado, Ana, Trevisan, Riccardo, Minnaert, Ben, Svanda, Milan, Pereira, Mário, Mongiardo, Mauro, Popov, Grigory, Pan, Ning, Aubert, Herve, Viani, Federico, Siachalou, Stavroula, Kant, Przemyslaw, Andia, Gianfranco, Polycarpou, Anastasis C., Cruz, Pedro, Mastri, Franco, Mazanek, Milo, Santos, Hugo, Alimenti, Federico, García-Vázquez, Hugo, Pollin, Sofie, Poli, Lorenzo, Belo, Daniel, Masotti, Diego, Machac, Jan, Tavares, Vítor, Mezzanotte, Paolo, Ndungidi, Papy, Oliveri, Giacomo, Fernandes, Ricardo, Salgado, Henrique, Moeyaert, Véronique, Massa, Andrea, Gonçalves, Ricardo, Pinho, Pedro, Giuseppina, Monti, Tarricone, Luciano, Dionigi, Marco, Russer, Peter, Russer, Johannes, Carvalho, Nb, ., ., Monti, Giuseppina, Dionigi, M, Russer, P, and Russer, J.

Subjects
Engineering, MULTIPLE MOBILE CHARGERS, EFFICIENCY, business.product_category, TRANSMISSION, Internet of Things, Wireless communication, Condensed Matter Physic, 02 engineering and technology, PRESSURE, Peak to average power ratio, Bandwidth, DESIGN, Electric vehicle, 0202 electrical engineering, electronic engineering, information engineering, Wireless, WIRELESS POWER TRANSFER, Wireless power transfer, Electronics, Electrical and Electronic Engineering, MICROSYSTEM, Power transmission, Radiation, Rectifiers, business.industry, WSN,Wireless Sensor Networks, 020208 electrical & electronic engineering, Electrical engineering, 020206 networking & telecommunications, Condensed Matter Physics, Europe, Transmission (telecommunications), SENSOR NETWORKS, ENERGY-TRANSFER, business, Telecommunications, Wireless sensor network, SYSTEM, 5G
Abstract

Summarization: This article presents European-based contributions for wireless power transmission (WPT), related to applications ranging from future Internet of Things (IoT) and fifth-generation (5G) systems to high-power electric vehicle charging. The contributors are all members of a European consortium on WPT, COST Action IC1301. WPT is the driving technology that will enable the next stage in the current consumer electronics revolution, including batteryless sensors, passive RF identification (RFID), passive wireless sensors, the IoT, and machine-to-machine solutions. The article discusses the latest developments in research by some of the members of this group. Presented on: IEEE Microwave Magazine

Published
2017

21. Efficient algorithm for passivity enforcement of S-parameter-based macromodels

Author

Dhaene, Tom, Deschrijver, Dirk, and Stevens, Nobby

Subjects
Least squares -- Methods, Algorithms -- Usage, Parameter estimation -- Methods, Microwave devices -- Research, Algorithm, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents an efficient and robust algorithm for passivity enforcement of S-parameter-based macromodels. The method computes updated values of the model residues by least squares fitting of nonpassive residuals of the scattering matrix. Several examples show that the proposed method yields accurate passive macromodels at a limited computational cost. Index Terms--Least squares fitting, macromodeling, model perturbation, passivity enforcement, vector fitting.

Published
2009

25. Model of a dipole antenna in free-space and near a perfectly electrical conducting plate

Author

Stevens, Nobby and Martens, Luc

Subjects
Antennas (Electronics), Business, Computers, Electronics, Electronics and electrical industries
Abstract

In this paper, an accurate method is developed to model dipole antennas in free-space or near an infinite perfectly electrical conducting plate. The magnetic field integral equation is implemented and point-matching is used to construct the interaction matrix. The edges of the cylinder, which can cause numerical instabilities in the simulated current distribution, are getting a special treatment by choosing a specific set of basis functions. The excitation is modeled based on the equivalence principle and leads to the application of a magnetic surface current over the gap region. The exact kernel of the integral equation is applied and all possible current components are taken into account. When the antenna is close to a conducting plate, a strong modification of the surface current distribution is observed. It is demonstrated that for these configurations, the incorporation of the circumferential component of the surface current distribution is needed. At larger distances, the circumferential surface current can be neglected in the total distribution. The only approximation (or rather assumption) we made is that we impose a longitudinal directed electrical field over the boundary of the gap region. The results are verified experimentally. Index Terms--Dipole antennas, magnetic field integral equation (MFIE), method of moments (MoM), scattering.

Published
2005

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