PhD. in Computer Science and Operations Research

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Publications

Hyperlinks to all publications are embedded in the title of the appropriate article.

Doctoral Thesis

My doctoral thesis is a “thesis by publication”, and is comprised of several of the listed papers in Network Design and Blockchain.

Title: “Scalable and Robust Fog-Computing Design & Dimensioning in Dynamic, Trustless Smart Cities”, April 2024.

Abstract: The concept of a Smart City relies on the full interconnectivity of several industries towards the amelioration of resident lifestyles. This is made possible by the growth and wide-spread use of the Internet of Things (IoT) -- a large network of data collection devices throughout multiple applications. However, most IoT devices have few resources, and rely on external servers to process and store the collected data. Due to high congestion and distance, Cloud data centres may cause high latency in their IoT response, which may be unacceptable in certain IoT applications. Instead, fog-computing has been proposed as a highly-virtualized heterogeneous layer of servers on the network edge, resulting in low-latency IoT data processing.

Current contributions in fog-computing assume a fog infrastructure is already in-place. Furthermore, each contribution requires different characteristics on the fog infrastructure. This thesis formulates a scalable and modifiable design & dimensioning scheme for a generalized fog infrastructure. This is modeled and solved as a mixed-integer linear program (MILP), and relaxed using several techniques such as Column Generation and Benders Decomposition.

Many concerns on the fog network performance are considered and addressed, such as high IoT traffic, network congestion, and fog node malfunctions.

Dynamic fog nodes, such as on-demand fog nodes and mobile fog-enabled unmanned aerial vehicles (fog-UAVs) are integrated into current design & dimensioning models to add flexibility and robustness to the network. A system based on blockchain and zero-knowledge proofs is introduced to enforce integrity on the fog nodes. The result is a scalable design & dimensioning scheme for a robust, flexible, and reliable fog infrastructure in a dynamic and malicious IoT-fog environment.

Link to Thesis

Network Design

I. Martinez, A. S. Hafid and M. Gendreau, "Design & Dimensioning of a UAV Set Covering in High-Traffic IoT-Fog Environments", in IEEE Internet of Things Journal, Accepted, November 2024.
I. Martinez, A. S. Hafid and M. Gendreau, "Robust and Fault-tolerant Fog Design & Dimensioning for Reliable Operation", in IEEE Internet of Things Journal, vol. 9, no. 19, pp. 18280-18292, March 2022.
I. Martinez, A. S. Hafid and A. Jarray, "Design, Resource Management and Evaluation of Fog Computing Systems: A Survey", in IEEE Internet of Things Journal, vol. 8, no. 4, pp. 2494-2516, February 2021.
I. Martinez, A. Jarray and A. S. Hafid, "Scalable Design and Dimensioning of Fog-Computing Infrastructure to Support Latency-Sensitive IoT Applications", in IEEE Internet of Things Journal, vol. 7, no. 6, pp. 5504-5520, June 2020.

Blockchain

I. Martinez, A. S. Hafid and M. Gendreau, “A Blockchain-Based Audit Mechanism for Trust and Integrity in IoT-Fog Environments”, in IEEE Transactions on Services Computing, Submitted, April 2024.
I. Martinez, S. Francis and A. S. Hafid, "Record and Reward Federated Learning Contributions with Blockchain," 2019 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery (CyberC), Guilin, China, 2019, pp. 50-57.