@article{karaja2023dynamic,
  title={Dynamic bag-of-tasks scheduling problem in a heterogeneous multi-cloud environment: a taxonomy and a new bi-level multi-follower modeling},
  author={Karaja, Mouna and Chaabani, Abir and Azzouz, Ameni and Ben Said, Lamjed},
  journal={The Journal of Supercomputing},
  volume={79},
  number={15},
  pages={17716--17753},
  year={2023},
  publisher={Springer}
}

@article{karaja2023efficient,
  title={Efficient bi-level multi objective approach for budget-constrained dynamic Bag-of-Tasks scheduling problem in heterogeneous multi-cloud environment},
  author={Karaja, Mouna and Chaabani, Abir and Azzouz, Ameni and Ben Said, Lamjed},
  journal={Applied Intelligence},
  volume={53},
  number={8},
  pages={9009--9037},
  year={2023},
  publisher={Springer}
}

A. Samti, I.Ben Jaafar, I.Nouaouri and P. Hirsch, A Novel NSGA-III-GKM++ Framework for Multi-Objective Cloud Resource Brokerage Optimization, Mathematics 13(13):2042, June 2025.

@INPROCEEDINGS{9151737,

author={Karaja, Mouna and Ennigrou, Meriem and Said, Lamjed Ben},

booktitle={2020 International Multi-Conference on: “Organization of Knowledge and Advanced Technologies” (OCTA)},

title={Budget-constrained dynamic Bag-of-Tasks scheduling algorithm for heterogeneous multi-cloud environment},

year={2020},

volume={},

number={},

pages={1-6},

keywords={Cloud computing;Task analysis;Dynamic scheduling;Bot (Internet);Scheduling algorithms;Heuristic algorithms;Bag-of-Tasks scheduling;budget-constrained;makespan;multi-cloud environment},

doi={10.1109/OCTA49274.2020.9151737}}

@InProceedings{10.1007/978-3-030-73050-5_17,
author= »Karaja, Mouna
and Ennigrou, Meriem
and Said, Lamjed Ben »,
editor= »Abraham, Ajith
and Hanne, Thomas
and Castillo, Oscar
and Gandhi, Niketa
and Nogueira Rios, Tatiane
and Hong, Tzung-Pei »,
title= »Solving Dynamic Bag-of-Tasks Scheduling Problem in Heterogeneous Multi-cloud Environment Using Hybrid Bi-Level Optimization Model »,
booktitle= »Hybrid Intelligent Systems »,
year= »2021″,
publisher= »Springer International Publishing »,
address= »Cham »,
pages= »171–180″,
isbn= »978-3-030-73050-5″
}

TY – JOUR
AU – Karaja, Mouna
AU – Chaabani, Abir
AU – Azzouz, Ameni
AU – Ben Said, Lamjed
PY – 2023
DA – 2023/04/01
TI – Efficient bi-level multi objective approach for budget-constrained dynamic Bag-of-Tasks scheduling problem in heterogeneous multi-cloud environment
JO – Applied Intelligence
SP – 9009
EP – 9037
VL – 53
IS – 8
AB – Bag-of-Tasks is a well-known model that processes big-data applications supporting embarrassingly parallel jobs with independent tasks. Scheduling Bag-of-Tasks in a dynamic multi-cloud environment is an NP-hard problem that has attracted a lot of attention in the last years. Such a problem can be modeled using a bi-level optimization framework due to its hierarchical scheme. Motivated by this issue, in this paper, an efficient bi-level multi-follower algorithm, based on hybrid metaheuristics, is proposed to solve the multi-objective budget-constrained dynamic Bag-of-Tasks scheduling problem in a heterogeneous multi-cloud environment. In our proposed model, the objective function differs depending on the scheduling level: The upper level aims to minimize the makespan of the whole Bag-of-Tasks under budget constraints; while each follower aims to minimize the makespan and the execution cost of tasks belonging to the Bag-of-Tasks. Since multiple conflicting objectives exist in the lower level, we propose an improved variant of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) called Efficient NSGA-II (E-NSGA-II), applying a recently proposed quick non-dominated sorting algorithm (QNDSA) with quasi-linear average time complexity. By performing experiments on proposed synthetic datasets, our algorithm demonstrates high performance in terms of makespan and execution cost while respecting budget constraints. Statistical analysis validates the outperformance of our proposal regarding the considering metrics.
SN – 1573-7497
UR – https://doi.org/10.1007/s10489-022-03942-1
DO – 10.1007/s10489-022-03942-1
ID – Karaja2023
ER –

TY – JOUR
AU – Karaja, Mouna
AU – Chaabani, Abir
AU – Azzouz, Ameni
AU – Ben Said, Lamjed
PY – 2023
DA – 2023/10/01
TI – Dynamic bag-of-tasks scheduling problem in a heterogeneous multi-cloud environment: a taxonomy and a new bi-level multi-follower modeling
JO – The Journal of Supercomputing
SP – 17716
EP – 17753
VL – 79
IS – 15
AB – Since more and more organizations deploy their applications through the cloud, an increasing demand for using inter-cloud solutions is noticed. Such demands could inherently result in overutilization of resources, which leads to resource starvation that is vital for time-intensive and life-critical applications. In this paper, we are interested in the scheduling problem in such environments. On the one hand, a new taxonomy of criteria to classify task scheduling problems and resolution approaches in inter-cloud environments is introduced. On the other hand, a bi-level multi-follower model is proposed to solve the budget-constrained dynamic Bag-of-Tasks (BoT) scheduling problem in heterogeneous multi-cloud environments. In the proposed model, the upper-level decision maker aims to minimize the BoT’ makespan under budget constraints. While each lower-level decision maker minimizes the completion time of tasks it received. Experimental results demonstrated the outperformance of the proposed bi-level algorithm and revealed the advantages of using a bi-level scheme with an improvement rate of 32%, 29%, and 21% in terms of makespan for the small, medium, and big size instances, respectively.
SN – 1573-0484
UR – https://doi.org/10.1007/s11227-023-05341-w
DO – 10.1007/s11227-023-05341-w
ID – Karaja2023
ER –