29 research outputs found
Can Artificial Noise Boost Further the Secrecy of Dual-hop RIS-aided Networks?
In this paper, we quantify the physical layer security of a dual-hop
regenerative relaying-based wireless communication system assisted by
reconfigurable intelligent surfaces (RISs). In particular, the setup consists
of a source node communicating with a destination node via a regenerative
relay. In this setup, a RIS is installed in each hop to increase the
source-relay and relay-destination communications reliability, where the RISs'
phase shifts are subject to quantization errors. The legitimate transmission is
performed under the presence of a malicious eavesdropper attempting to
compromise the legitimate transmissions by overhearing the broadcasted signal
from the relay. To overcome this problem, we incorporate a jammer to increase
the system's secrecy by disrupting the eavesdropper through a broadcasted
jamming signal. Leveraging the well-adopted Gamma and Exponential distributions
approximations, the system's secrecy level is quantified by deriving
approximate and asymptotic expressions of the secrecy intercept probability
(IP) metric in terms of the main network parameters. The results show that the
secrecy is enhanced significantly by increasing the jamming power and/or the
number of reflective elements (REs). In particular, an IP of approximately
can be reached with REs and dB of jamming power-to-noise
ratio even when the legitimate links' average signal-to-noise ratios are
-dB less than the eavesdropper's one. We show that cooperative jamming is
very helpful in strong eavesdropping scenarios with a fixed number of REs, and
the number of quantization bits does not influence the secrecy when exceeding
bits. All the analytical results are endorsed by Monte Carlo simulations
Continual Conscious Active Fine-Tuning to Robustify Online Machine Learning Models Against Data Distribution Shifts
Unlike their offline traditional counterpart, online machine learning models
are capable of handling data distribution shifts while serving at the test
time. However, they have limitations in addressing this phenomenon. They are
either expensive or unreliable. We propose augmenting an online learning
approach called test-time adaptation with a continual conscious active
fine-tuning layer to develop an enhanced variation that can handle drastic data
distribution shifts reliably and cost-effectively. The proposed augmentation
incorporates the following aspects: a continual aspect to confront the
ever-ending data distribution shifts, a conscious aspect to imply that
fine-tuning is a distribution-shift-aware process that occurs at the
appropriate time to address the recently detected data distribution shifts, and
an active aspect to indicate employing human-machine collaboration for the
relabeling to be cost-effective and practical for diverse applications. Our
empirical results show that the enhanced test-time adaptation variation
outperforms the traditional variation by a factor of two
Comparaison des décodeurs de Chase, l'OSD et ceux basés sur les algorithmes génétiques
Les dĂ©codeurs basĂ©s sur les algorithmes gĂ©nĂ©tiques (AG) appliquĂ©s aux codes BCH ont de bonnes performances par rapport Ă Chase-2 et l'OSD d'ordre 1 et atteignent les performances de l'OSD-3 pour quelques codes RĂ©sidu Quadratiques (RQ). Ces algorithmes restent moins complexes pour les codes linĂ©aires de grandes longueurs; en plus leurs performances peuvent ĂȘtre amĂ©liorĂ©es en changeant les paramĂštres, en particulier le nombre d'individus par population et le nombre de gĂ©nĂ©rations, ce qui les rend attractifs