Olfa Ben ahmed

Dr. Olfa Ben ahmed


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

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

Representative Publications

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26 October 2020 in IEEE Transactions on Industrial Informatics
Verified
Journal Article
Closed access
SMSeifeddine Messaoud
Seifeddine Messaoud
ABAbbas BRADAI
Abbas BRADAI
OAOlfa Ben ahmed
Olfa Ben ahmed
PQPham Tran Anh Quang
Pham Tran Anh Quang
Mohamed AtriMohamed Atri
Mohamed Atri
MHMohammad Anwar Hossain
Mohammad Anwar Hossain
Fifth-Generation and beyond networks are envisioned to support multi-Industrial IoT (IIoT) applications with a diverse QoS requirements. Network slicing is recognized as a flagship technology that enables IIoT networks with multiservices and resource requirements by allowing the networkas-infrastructure transition to the network-as-service. Motivated by the increasing IIoT computational capacity, and taking into consideration the QoS satisfaction and private data sharing challenges, federated reinforcement learning (RL) has become a promising approach that distributes data acquisition and computation tasks over distributed network agents, exploiting local computation capacities and agents self-learning experiences. This paper proposes a novel deep RL scheme to provide a federated and dynamic network management and resource allocation for differentiated QoS services in future IIoT networks. This involves IIoT slices resource allocation in terms of Transmission Power (TP) and Spreading Factor (SF) according to the slices QoS requirements. Toward this goal, the proposed Deep Federated Q-Learning (DFQL) is reached into two main steps: First, we propose a Multi-Agent deep Q-learning (MAQL)-based dynamic slices TP and SF adjustment process that aims at maximizing selfQoS requirements in term of throughput and delay. Second, the Deep Federated Learning (DFL) is proposed to learn Multi-Agent Self model and enable them to find an optimal action decision on the TP and the SF that satisfy IIoT virtual network slice QoS reward, exploiting the shared experiences between agents. Simulation results show that the proposed DFQL framework achieves efficient performance compared to the traditional approaches.

8 September 2021 in Neural Computing and Applications
Verified
Journal Article
Closed access
PDF file
SBSoulef Bouaafia
Soulef Bouaafia
RKRanda Khemiri
Randa Khemiri
SMSeifeddine Messaoud
Seifeddine Messaoud
OAOlfa Ben ahmed
Olfa Ben ahmed
FSFatma Ezahra Sayadi
Fatma Ezahra Sayadi

21 June 2022 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
TTThanh Lam TU
Thanh Lam TU
ABAbbas BRADAI
Abbas BRADAI
OAOlfa Ben ahmed
Olfa Ben ahmed
SGSahil Garg
Sahil Garg
YPYannis Pousset
Yannis Pousset
GKGeorges Kaddoum
Georges Kaddoum
The optimal transmit power that maximizes energy efficiency (EE) in Longe Range (LoRa) networks is investigated by using the deep learning (DL) approach. Particularly, the proposed artificial neural network (ANN) is trained two times; in the first phase, the ANN is trained by the model-based data which are generated from the simplified system model while in the second phase, the pre-trained ANN is re-trained by the practical data. Numerical results show that the proposed approach outperforms the conventional one which directly trains with the practical data. Moreover, the performance of the proposed ANN under both partial and full optimum architecture are studied. The results depict that the gap between these architectures is negligible. Finally, our findings also illustrate that instead of fully re-trained the ANN in the second training phase, freezing some layers is also feasible since it does not significantly decrease the performance of the ANN.

2 December 2024 in Image and Vision Computing
Verified
Journal Article
Closed access
AOAchraf Ouahab
Achraf Ouahab
OAOlfa Ben ahmed
Olfa Ben ahmed

12 March 2019 in Remote Sensing
Verified
Journal Article
Open access
PDF file
OAOlfa Ben ahmed
Olfa Ben ahmed
TUThierry Urruty
Thierry Urruty
NRNoël Richard
Noël Richard
Christine Fernandez-MaloigneChristine Fernandez-Maloigne
Christine Fernandez-Maloigne
With the emergence of huge volumes of high-resolution Hyperspectral Images (HSI) produced by different types of imaging sensors, analyzing and retrieving these images require effective image description and quantification techniques. Compared to remote sensing RGB images, HSI data contain hundreds of spectral bands (varying from the visible to the infrared ranges) allowing profile materials and organisms that only hyperspectral sensors can provide. In this article, we study the importance of spectral sensitivity functions in constructing discriminative representation of hyperspectral images. The main goal of such representation is to improve image content recognition by focusing the processing on only the most relevant spectral channels. The underlying hypothesis is that for a given category, the content of each image is better extracted through a specific set of spectral sensitivity functions. Those spectral sensitivity functions are evaluated in a Content-Based Image Retrieval (CBIR) framework. In this work, we propose a new HSI dataset for the remote sensing community, specifically designed for Hyperspectral remote sensing retrieval and classification. Exhaustive experiments have been conducted on this dataset and on a literature dataset. Obtained retrieval results prove that the physical measurements and optical properties of the scene contained in the HSI contribute in an accurate image content description than the information provided by the RGB image presentation.

15 September 2022
Verified
Book Chapter
Closed access
PDF file
AOAchraf Ouahab
Achraf Ouahab
OAOlfa Ben ahmed
Olfa Ben ahmed
CFChristine Fernandez-Maloigne
Christine Fernandez-Maloigne