VLDB 2026 Research / reviewers in the wild / expert
Ismail Lotfi
dblp:327/7846
· DBLP profile ↗
6ranked-venue papers
5as first author
6since 2021 · last 2026
0000-0003-4034-9381ORCID · corroborated
Domains — the database's venue-derived domains; a paper can count in several
Computer networks · 6 · 5 first-author · 6 since 2021
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2026 | Large Language Models as Bidding Agents in Repeated HetNet Auction
Ismail Lotfi, Ali Ghrayeb, Samson Lasaulce, Mérouane Debbah |
WCNC | 1 |
| 2025 | TeleOracle: Fine-Tuned Retrieval-Augmented Generation With Long-Context Support for NetworksabstractThe telecommunications industry’s rapid evolution demands intelligent systems capable of managing complex networks and adapting to emerging technologies. While large language models (LLMs) show promise in addressing these challenges, their deployment in telecom environments faces significant constraints due to edge device limitations and inconsistent documentation. To bridge this gap, we present TeleOracle, a telecom-specialized retrieval-augmented generation (RAG) system built on the Phi-2 small language model (SLM). To improve context retrieval, TeleOracle employs a two-stage retriever that incorporates semantic chunking and hybrid key-word and semantic search. Additionally, we expand the context window during inference to enhance the model’s performance on open-ended queries. We also employ low-rank adaption for efficient fine-tuning. A thorough analysis of the model’s performance indicates that our RAG framework is effective in aligning Phi-2 to the telecom domain in a downstream question and answer (QnA) task, achieving a 30% improvement in accuracy over the base Phi-2 model, reaching an overall accuracy of 81.20%. Notably, we show that our model not only performs on par with the much larger LLMs but also achieves a higher faithfulness score, indicating higher adherence to the retrieved context. Nouf Alabbasi, Omar Erak, Omar Alhussein, Ismail Lotfi, Sami Muhaidat, Mérouane Debbah |
IEEE Internet Things J. | 4 |
| 2024 | Enhancing Trust and Security in the Vehicular Metaverse: A Reputation-Based Mechanism for Participants with Moral HazardabstractIn this paper, we tackle the issue of moral hazard within the realm of the vehicular Metaverse. A pivotal facilitator of the vehicular Metaverse is the effective orchestration of its market elements, primarily comprised of sensing internet of things (SIoT) devices. These SIoT devices play a critical role by furnishing the virtual service provider (VSP) with real-time sensing data, allowing for the faithful replication of the physical environment within the virtual realm. However, SIoT devices with intentional misbehavior can identify a loophole in the system post-payment and proceeds to deliver falsified content, which cause the whole vehicular Metaverse to collapse. To combat this significant problem, we propose an incentive mechanism centered around a reputation-based strategy. Specifically, the concept involves maintaining reputation scores for participants based on their interactions with the VSP. These scores are derived from feedback received by the VSP from Metaverse users regarding the content delivered by the VSP and are managed using a subjective logic model. Nevertheless, to prevent “good” SIoT devices with false positive ratings to leave the Metaverse market, we build a vanishing-like system of previous ratings so that the VSP can make informed decisions based on the most recent and accurate data available. Finally, we validate our proposed model through extensive simulations. Our primary results show that our mechanism can efficiently prevent malicious devices from starting their poisoning attacks. At the same time, trustworthy SIoT devices that had a previous miss-classification are not banned from the market. Ismail Lotfi, Marwa Qaraqe, Ali Ghrayeb, Dusit Niyato |
WCNC | 1 |
| 2024 | Semantic Information Marketing in the Metaverse: A Learning-Based Contract Theory FrameworkabstractIn this paper, we address the problem of designing incentive mechanisms by a virtual service provider (VSP) to hire sensing IoT devices to sell their sensing data to help creating and rendering the digital copy of the physical world in the Metaverse. Due to the limited bandwidth, we propose to use semantic extraction algorithms to reduce the delivered data by the sensing IoT devices. Nevertheless, mechanisms to hire sensing IoT devices to share their data with the VSP and then deliver the constructed digital twin to the Metaverse users are vulnerable to adverse selection problem. The adverse selection problem, which is caused by information asymmetry between the system entities, becomes harder to solve when the private information of the different entities are multi-dimensional. We propose a novel iterative contract design and use a new variant of multi-agent reinforcement learning (MARL) to solve the modelled multi-dimensional contract problem. To demonstrate the effectiveness of our algorithm, we conduct extensive simulations and measure several key performance metrics of the contract for the Metaverse. Our results show that our designed iterative contract is able to incentivize the participants to interact truthfully, which maximizes the profit of the VSP with minimal individual rationality (IR) and incentive compatibility (IC) violation rates. Furthermore, the proposed learning-based iterative contract framework has limited access to the private information of the participants, which is to the best of our knowledge, the first of its kind in addressing the problem of adverse selection in incentive mechanisms. Ismail Lotfi, Dusit Niyato, Sumei Sun, Dong In Kim 0001, Xuemin Shen |
IEEE J. Sel. Areas Commun. | 1 |
| 2024 | On the Robustness of Channel Allocation in Joint Radar and Communication Systems: An Auction ApproachabstractJoint radar and communication (JRC) is a promising technique for spectrum re-utilization, which enables radar sensing and data transmission to operate on the same frequencies and the same devices. However, due to the multi-objective property of JRC systems, channel allocation to JRC nodes should be carefully designed to maximize system performance. Additionally, because of the broadcast nature of wireless signals, a watchful adversary, i.e., a warden, can detect ongoing transmissions and attack the system. Thus, we develop a covert JRC system that minimizes the detection probability by wardens, in which friendly jammers are deployed to improve the covertness of the JRC nodes during radar sensing and data transmission operations. Furthermore, we propose a robust multi-item auction design for channel allocation for such a JRC system that considers the uncertainty in bids. The proposed auction mechanism achieves the properties of truthfulness, individual rationality, budget feasibility, and computational efficiency. The simulations clearly show the benefits of our design to support covert JRC systems and to provide incentive to the JRC nodes in obtaining spectrum, in which the auction-based channel allocation mechanism is robust against perturbations in the bids, which is highly effective for JRC nodes working in uncertain environments. Ismail Lotfi, Hongyang Du 0001, Dusit Niyato, Sumei Sun, Dong In Kim 0001 |
IEEE Trans. Mob. Comput. | 1 |
| 2021 | Social Welfare Maximization Auction in Joint Radar Communication Systems for Autonomous VehiclesabstractJoint radar-communications (JRC) has been proposed recently for autonomous vehicles (AVs) to simultaneously perform radar sensing, e.g., detecting distant vehicles and pedestrian, and data transmission, e.g., to edge computing services, all on the same waves. However, due to the high AV density in urban area, the spectrum service provider (SSP) needs to allocate the spectrum resources optimally. In this paper, we consider the social welfare of the network which is defined as the total revenue of the SSP and the utilities of the AV users, and propose an auction-based algorithm to model the competition among the AV users to obtain the spectrum resources and maximize the social welfare. Since some AV users can have critical and useful information about each other (e.g., AV neighbours sharing traffic data), we consider the network effect in our proposed auction mechanism to incentivize more AV users to join the auction. The numerical results demonstrate the effectiveness of our proposed design compared to traditional schemes. Ismail Lotfi, Dusit Niyato, Sumei Sun, Dong In Kim 0001 |
GLOBECOM | 1 |