Results 31 to 40 of about 3,586 (255)

Covert Communications through Imperfect Cancellation

Proceedings of the 2022 ACM Workshop on Information Hiding and Multimedia Security, 2022
We propose a method for covert communications using an IEEE 802.11 OFDM/QAM packet as a carrier. We show how to hide the covert message so that the transmitted signal does not violate the spectral mask specified by the standard, and we determine its impact on the OFDM packet error rate. We show conditions under which the hidden signal is not usable and
Daniel Chew, Christine Nguyen, Samuel Berhanu, Chris Baumgart, A. Brinton Cooper   +4 more
openaire   +2 more sources

Coupling of Er3+ ions and Plasmonic Modes in Vertical Nanocavities for Spectral Broadening in Telecom Bands

Advanced Materials Technologies, EarlyView.
Left: Illustration of the glass & nanostructures system and the NIR emission at 1.5 µm, where the colored spheres represent the Er3+ ions within the doped glass. Right: Representation of the Stark splitting of the 4I13/2 and 4I15/2 manifolds of the Er3+, illustrating how the plasmonic modes facilitate the emission from the broader Stark manifold ...
Gaston Lozano Calderón, Víctor Anthony García Rivera, Stéphan Cagnon, Souleymane Toubou Bah, Younès Messaddeq, Euclydes Marega Junior   +5 more
wiley   +1 more source

Covert Multi-Access Communication with a Non-Covert User

ICC 2024 - IEEE International Conference on Communications
In this paper, we characterize the fundamental limits of a communication system with three users (i.e., three transmitters) and a single receiver where communication from two covert users must remain undetectable to an external warden. Our results show a tradeoff between the highest rates that are simultaneously achievable for the three users.
Abdelaziz Bounhar, Mireille Sarkiss, Michèle A. Wigger   +2 more
openaire   +2 more sources

Biodegradable Wireless Soil Urea Sensor Using Metamaterial Perfect Absorber for Distributed Deployment in Precision Agriculture

Advanced Materials Technologies, EarlyView.
In this study, we propose a biodegradable wireless soil urea sensor for precision agriculture. The sensor's electromagnetic response varies depending on the urea concentration, allowing the measurement of relative soil urea concentrations by analyzing the time‐transient electromagnetic response.
Yu Tanaami, Ken Sakabe, Tetsuya Yarimizo, Yasutaka Murakami, Tetsuo Kan, Hiroaki Onoe   +5 more
wiley   +1 more source

Non‐Volatile Silicon Mach‐Zehnder Switches with 0.7 π Phase Shift Based on Graphene Heaters and Sb2Se3 Phase Change Material

Advanced Optical Materials, EarlyView.
ABSTRACT Photonic integrated circuits (PICs) can deliver unparalleled performance for future neuromorphic computing applications. Such neuromorphic PICs require a large number of tunable switches, which are typically realized with current‐controlled heaters, resulting in considerable energy consumption.
Jens Samland, Felix Hoff, Timo Veslin, Holger Lerch, Bartos Chmielak, Martin Otto, Caroline Porschatis, Bárbara Canto, Stephan Suckow, Matthias Wuttig, Max C. Lemme   +10 more
wiley   +1 more source

Covert Wireless Communications in a Dynamic Environment

, 2017
This dissertation investigates covert communication in dynamic wireless communication environments. A key goal is to provide insight about the capabilities of a transmitter desiring to remain covert and analogously, the capabilities of the party ...
Sobers, Tamara V
core   +1 more source

Behavioral Mimicry Covert Communication [PDF]

, 2012
In this paper, the use of structural behavior of communication protocols (e.g., CSMA) in designing new covert channels is investigated. In this way, the covert transmitter adopts the communication protocol architecture to control its overt traffic flow yet with different parameters that give it enough freedom to embed the covert message in its overt ...
Seyed Ali Ahmadzadeh, Gordon B. Agnew
openaire   +1 more source

Covert Communication in Autoencoder Wireless Systems

CoRR, 2023
Hiding the wireless communication by transmitter Alice to intended receiver Bob from a capable and attentive adversary Willie has been widely studied under the moniker "covert communications". However, when such covert communication is done in the presence of allowable system communications, there has been little study of both hiding the signal and ...
Ali Mohammadi Teshnizi, Majid Ghaderi, Dennis Goeckel   +2 more
openaire   +2 more sources

Direct Measurement of the Singlet Lifetime and Photoexcitation Behavior of the Boron Vacancy Center in Hexagonal Boron Nitride

Advanced Optical Materials, EarlyView.
Negatively charged boron vacancy defects in hexagonal boron nitride promise near‐surface quantum sensing, but their internal spin transition rates are only partly understood. This work directly measures the defect's singlet‐state lifetime, 15(3) ns, using a nanosecond rise‐time dual‐pulse photoluminescence‐recovery method, and shows that high laser ...
Richard A. Escalante, Andrew J. Beling, Daniel G. Ang, Niko R. Reed, Justin J. Welter, John W. Blanchard, Cecilia Campos, Edwin Coronel, Klaus Krambrock, Alexandre S. Leal, Paras N. Prasad, Ronald L. Walsworth   +11 more
wiley   +1 more source

A Game-Theoretic Approach to Covert Communications

, 2020
This paper considers a game-theoretic formulation of the covert communications problem with finite blocklength, where the transmitter (Alice) can randomly vary her transmit power in different blocks, while the warden (Willie) can randomly vary his ...
Quevedo, Daniel E.,, Daniel E. Quevedo, Alex S. Leong, Leong, Alex S.,, Subhrakanti Dey, Dey, Subhrakanti,   +5 more
core   +1 more source