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2025Zakia Zouaghia, Zahra Kodia, Lamjed Ben Said
A novel approach for dynamic portfolio management integrating K-means clustering, mean-variance optimization, and reinforcement learning
Knowledge and Information Systems, 1-73., 2025
Résumé
Effective portfolio management is crucial in today’s fast-moving and unpredictable financial landscape. This paper introduces a powerful and adaptive investment framework that fuses classical portfolio theory with cutting-edge artificial intelligence (AI) to optimize portfolio performance during volatile market conditions. Our methodology seamlessly integrates K-means clustering to identify asset groupings based on correlation structures of technical indicators, mean-variance optimization (MVO) to achieve an ideal risk-return trade-off, and advanced Machine Learning (ML) and reinforcement learning (RL) techniques to dynamically adjust asset allocations and simulate market behavior. The proposed framework is rigorously evaluated on historical stock data from 60 prominent stocks listed on NASDAQ, NYSE, and S&P 500 indices between 2021 and 2024, a period marked by significant economic shocks, global uncertainty, and structural market shifts. Our experimental results show that our framework consistently outperforms traditional strategies and recent state of the art models, achieving superior metrics including Sharpe ratio, Sortino ratio, annual return, maximum drawdown, and Calmar ratio. We also assess the computational efficiency of the approach, ensuring its feasibility for real-world deployment. This work demonstrates the transformative potential of AI-driven portfolio optimization in empowering investors to make smarter, faster, and more resilient financial decisions amid uncertainty.
Boutheina Drira, Haykel Hamdi, Ines Ben JaafarHybrid Deep Learning Ensemble Models for Enhanced Financial Volatility Forecasting
Second Edition IEEE Afro-Mediterranean Conference on Artificial Intelligence 2025 IEEE AMCAI IEEE AMCAI 2025, 2025
Résumé
this paper presents a novel ensemble
methodology that integrates deep learning models to enhance
the accuracy and robustness of financial volatility forecasts. By
combining Convolutional Neural Networks (CNNs) and GRU
networks, the proposed approach captures both spatial and
temporal patterns in financial time series data. Empirical results
demonstrate the superiority of this ensemble model over
traditional forecasting methods in various financial markets.
Keywords: Volatility Forecasting, Deep Learning, Ensemble
Modeling, CNN, GRU, Financial Time Series -
2024Zakia Zouaghia, Zahra Kodia, Lamjed Ben Said
A novel AutoCNN model for stock market index prediction
Journal of Telecommunications and the Digital Economy, 12(1), 612-636., 2024
Résumé
Stock markets have an important impact on economic growth of countries. The prediction
of stock market indexes has been a complex task for last years. Indeed, many researches and financial analysts are highly interested in the research area of stock market prediction. In this paper, we propose a novel framework, titled AutoCNN based on artificial intelligence techniques, to predict future stock market indexes. AutoCNN is composed mainly of three stages: (1) CNN for Automatic Feature Extraction, (2) The Halving Grid Search algorithm is combined to CNN model for stock indexes prediction and (3) Evaluation and recommendation. To validate our AutoCNN, we conduct experiments on two financial datasets that are extracted in the period between 2018 and 2023, which includes several events such as economic, health and geopolitical international crises. The performance of AutoCNN model is quantified using various metrics. It is benchmarked against different models and it proves strong prediction abilities. AutoCNN contributes to emerging technologies and innovation in the financial sector by automating decision-making, leveraging advanced pattern recognition, and enhancing the overall decision support system for investors in the digital economy. -
2022Zahra Fathalli, Zahra Kodia, Lamjed Ben Said
Stock market prediction of Nifty 50 index applying machine learning techniques
Applied Artificial Intelligence, 36:1, 2111134, 2022
Résumé
The stock market is viewed as an unpredictable, volatile, and
competitive market. The prediction of stock prices has been
a challenging task for many years. In fact, many analysts are
highly interested in the research area of stock price prediction.
Various forecasting methods can be categorized into linear and
non-linear algorithms. In this paper, we offer an overview of the
use of deep learning networks for the Indian National Stock
Exchange time series analysis and prediction. The networks
used are Recurrent Neural Network, Long Short-Term Memory
Network, and Convolutional Neural Network to predict future
trends of NIFTY 50 stock prices. Comparative analysis is done
using different evaluation metrics. These analysis led us to
identify the impact of feature selection process and hyperparameter optimization on prediction quality and metrics used in the prediction of stock market performance and prices. The performance of the models was quantified using MSE metric.
These errors in the LSTM model are found to be lower compared
to RNN and CNN models. -
2014Lamjed Ben Said, Zahra Kodia, Khaled Ghedira
Design Of Cognitive Investor Making Decision For An Artificial Stock Market Simulation: A Behavior-based Approach
Soft-Computing in Capital Market: Research and Methods of Computational Finance for Measuring Risk of Financial Instruments,2014, 41-56., 2014
Résumé
Computational Finance, an exciting new cross-disciplinary research area, depends extensively on the tools and techniques of computer science, statistics, information systems and financial economics for educating the next generation of financial researchers, analysts, risk managers, and financial information technology professionals. This new discipline, sometimes also referred to as "Financial Engineering" or "Quantitative Finance" needs professionals with extensive skills both in finance and mathematics along with specialization in computer science. Soft-Computing in Capital Market hopes to fulfill the need of applications of this offshoot of the technology by providing a diverse collection of cross-disciplinary research. This edited volume covers most of the recent, advanced research and practical areas in computational finance, starting from traditional fundamental analysis using algebraic and geometric tools to the logic of science to explore information from financial data without prejudice. Utilizing various methods, computational finance researchers aim to determine the financial risk with greater precision that certain financial instruments create. In this line of interest, twelve papers dealing with new techniques and/or novel applications related to computational intelligence, such as statistics, econometrics, neural- network, and various numerical algorithms are included in this volume.
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2011Zahra Kodia, Lamjed Ben Said, Khaled Ghedira
Simulation comportementale à base d’agents de la dynamique du marché boursier: Modèle cognitif de l’investisseur
Revue d'intelligence artificielle, 25(1), 83-107., 2011
Résumé
This paper explores the dynamics of stock market from a behavioral perspective using
a multi-agent simulation. The aim of this paper is to study the behavior of investors in the stock
market to find a model as close as possible to reality. The main problem is to understand,
through a novel model which includes behavioral and cognitive attitudes of the investor, the
running of the market and determine the sources of his complexity. Simulation experiments are
being performed to observe stylized facts of the financial time series. These experiments show
that representing a behavioral model allows to observe emergent socio-economic phenomena. -
2010Zahra Kodia, Lamjed Ben Said, Khaled Ghedira
A Study of Stock Market Trading Behavior and Social Interactions through a Multi Agent Based Simulation
Agent and Multi-Agent Systems: Technologies and Applications, 4th KES International Symposium, KES-AMSTA 2010, June 23-25, 2010, Proceedings. Part II pp. 302-311, Gdynia, Poland., 2010
Résumé
In this paper, we study the stock market trading behavior and the interactions between traders. We propose a novel model which includes behavioral and cognitive attitudes of the trader at the micro level and explains their effects on his decision making at the macro level. The proposed simulator is composed of heterogeneous Trader agents with a behavioral cognitive model and the CentralMarket agent matching buying and selling orders. Our artificial stock market is implemented using distributed artificial intelligence techniques. The resulting simulation system is a tool able to numerically simulate financial market operations in a realistic way. Experiments show that representing the micro level led us to validate some stylized facts related to stock market and to observe emergent socio-economic phenomena at the macro level.
Zahra Kodia, Lamjed Ben Said, Khaled GhediraStylized facts study through a multi-agent based simulation of an artificial stock market
Lecture Notes in Economics and Mathematical Systems, in: Marco Li Calzi & Lucia Milone & Paolo Pellizzari (ed.), Progress in Artificial Economics, pages 27-38, Springer., 2010
Résumé
This paper explores the dynamics of stock market from a psychological perspective using a multi-agent simulation model. We study the stock market trading behavior and the interactions between traders. We propose a novel model which includes behavioral and cognitive attitudes of the trader at the micro level and explains their effects on his decision making at the macro level. The proposed simulator is composed of heterogeneous Trader agents with a behavioral cognitive model and the CentralMarket agent matching buying and selling orders. Simulation experiments are being performed to observe stylized facts of the financial times series and to show that the psychological attitudes have many consequences on the stock market dynamics. These experiments show that the modelization of the micro level led us to observe emergent socio-economic phenomena at the macro level.
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2009Zahra Kodia, Lamjed Ben Said
Multi-agent Simulation of Investor Cognitive Behavior in Stock Market
7th International Conference on PAAMS'09, AISC 55, pp.90-99, Salamanca, Spain. Springer Berlin / Heidelberg; ISSN: 1615-3871, 2009
Résumé
In this paper, we introduce a new model of Investor cognitive behavior in stock market. This model describes the behavioral and cognitive attitudes of the Investor at the micro level and explains their effects on his decision making. A theoretical framework is discussed in order to integrate a set of multidisciplinary concepts. A Multi-Agent Based Simulation (MABS) is used to: (1) validate our model, (2) build an artificial stock market: SiSMar and (3) study the emergence of certain phenomena relative to the stock market dynamics at the macro level. The proposed simulator is composed of heterogeneous Investor agents with a behavioral cognitive model, an Intermediary agent and the CentralMarket agent matching buying and selling orders. Our artificial stock market is implemented using distributed artificial intelligence techniques. The resulting simulator is a tool able to numerically simulate financial market operations in a realistic way. Preliminary results show that representing the micro level led us to build the stock market dynamics, and to observe emergent socio-economic phenomena at the macro level.
Zahra Kodia, Lamjed Ben Said, Khaled GhediraSiSMar: social multi-agent based simulation of stock market
AAMAS '09: Proceedings of The 8th International Conference on Autonomous Agents and Multiagent Systems - Volume 2 Pages 1345 - 1346, 2009
Résumé
In this paper, we introduce a new model of the stock market. This model describes the behavioral and cognitive attitudes of the investor at the micro level and explains their effects on his decision making. A multi-agent based simulation is used to validate our model and to study the emergence of certain stock market phenomena at the macro level. The modelling and implementation details of our simulator will appear in the full version of the paper.
BibTeX
@article{zouaghia2024novel,
title={A novel AutoCNN model for stock market index prediction},
author={Zouaghia, Zakia and Kodia, Zahra and Ben Said, Lamjed},
journal={Journal of Telecommunications and the Digital Economy},
volume={12},
number={1},
pages={612--636},
year={2024},
publisher={Telecommunications Association [South Melbourne, Vic.]}
}
BibTeX
@article{zouaghia2025novel,
title={A novel approach for dynamic portfolio management integrating K-means clustering, mean-variance optimization, and reinforcement learning: Z. Zouaghia et al.},
author={Zouaghia, Zakia and Kodia, Zahra and Ben said, Lamjed},
journal={Knowledge and Information Systems},
pages={1--73},
year={2025},
publisher={Springer}
}
BibTeX
@InProceedings{10.1007/978-3-642-00487-2_10,
author= »Kodia, Zahra
and Said, Lamjed Ben »,
editor= »Demazeau, Yves
and Pav{\’o}n, Juan
and Corchado, Juan M.
and Bajo, Javier »,
title= »Multi-agent Simulation of Investor Cognitive Behavior in Stock Market »,
booktitle= »7th International Conference on Practical Applications of Agents and Multi-Agent Systems (PAAMS 2009) »,
year= »2009″,
publisher= »Springer Berlin Heidelberg »,
address= »Berlin, Heidelberg »,
pages= »90–99″,
abstract= »In this paper, we introduce a new model of Investor cognitive behavior in stock market. This model describes the behavioral and cognitive attitudes of the Investor at the micro level and explains their effects on his decision making. A theoretical framework is discussed in order to integrate a set of multidisciplinary concepts. A Multi-Agent Based Simulation (MABS) is used to: (1) validate our model, (2) build an artificial stock market: SiSMar and (3) study the emergence of certain phenomena relative to the stock market dynamics at the macro level. The proposed simulator is composed of heterogeneous Investor agents with a behavioral cognitive model, an Intermediary agent and the CentralMarket agent matching buying and selling orders. Our artificial stock market is implemented using distributed artificial intelligence techniques. The resulting simulator is a tool able to numerically simulate financial market operations in a realistic way. Preliminary results show that representing the micro level led us to build the stock market dynamics, and to observe emergent socio-economic phenomena at the macro level. »,
isbn= »978-3-642-00487-2″
}
BibTeX
@inproceedings{kodia2009sismar,
title={SiSMar: social multi-agent based simulation of stock market},
author={Kodia, Zahra and Said, Lamjed Ben and Ghedira, Khaled},
booktitle={Proceedings of The 8th International Conference on Autonomous Agents and Multiagent Systems-Volume 2},
pages={1345--1346},
year={2009}
}
BibTeX
@InProceedings{10.1007/978-3-642-00487-2_10,
author= »Kodia, Zahra
and Said, Lamjed Ben »,
editor= »Demazeau, Yves
and Pav{\’o}n, Juan
and Corchado, Juan M.
and Bajo, Javier »,
title= »Multi-agent Simulation of Investor Cognitive Behavior in Stock Market »,
booktitle= »7th International Conference on Practical Applications of Agents and Multi-Agent Systems (PAAMS 2009) »,
year= »2009″,
publisher= »Springer Berlin Heidelberg »,
address= »Berlin, Heidelberg »,
pages= »90–99″,
abstract= »In this paper, we introduce a new model of Investor cognitive behavior in stock market. This model describes the behavioral and cognitive attitudes of the Investor at the micro level and explains their effects on his decision making. A theoretical framework is discussed in order to integrate a set of multidisciplinary concepts. A Multi-Agent Based Simulation (MABS) is used to: (1) validate our model, (2) build an artificial stock market: SiSMar and (3) study the emergence of certain phenomena relative to the stock market dynamics at the macro level. The proposed simulator is composed of heterogeneous Investor agents with a behavioral cognitive model, an Intermediary agent and the CentralMarket agent matching buying and selling orders. Our artificial stock market is implemented using distributed artificial intelligence techniques. The resulting simulator is a tool able to numerically simulate financial market operations in a realistic way. Preliminary results show that representing the micro level led us to build the stock market dynamics, and to observe emergent socio-economic phenomena at the macro level. »,
isbn= »978-3-642-00487-2″
}
BibTeX
@Chapter{repec:spr:lnechp:978-3-642-13947-5_3,
publisher={Springer},
series={Lecture Notes in Economics and Mathematical Systems},
edition={None},
booktitle={Progress in Artificial Economics},
chapter={None},
author={Zahra Kodia and Lamjed Ben Said and Khaled Ghedira},
title={Stylized Facts Study through a Multi-Agent Based Simulation of an Artificial Stock Market},
year={2010},
month={December},
pages={27-38},
volume={None},
abstract={ This paper explores the dynamics of stock market from a psychological perspective using a multi-agent simulation model. We study the stock market trading behavior and the interactions between traders. We propose a novel model which includes behavioral and cognitive attitudes of the trader at the micro level and explains their effects on his decision making at the macro level. The proposed simulator is composed of heterogeneous Trader agents with a behavioral cognitive model and the CentralMarket agent matching buying and selling orders. Simulation experiments are being performed to observe stylized facts of the financial times series and to show that the psychological attitudes have many consequences on the stock market dynamics. These experiments show that the modelization of the micro level led us to observe emergent socio-economic phenomena at the macro level.},
keywords={Stock Market; Stylize Fact; Price Return; Order Book; Informational Process},
doi={10.1007/978-3-642-13947-5_3},
url={https://ideas.repec.org/h/spr/lnechp/978-3-642-13947-5_3.html},
}
BibTeX
@Chapterbook{BSLChapter,
title={Design Of Cognitive Investor Making Decision For An Artificial Stock Market Simulation: A Behavior-based Approach},
booktitle={Soft-Computing in Capital Market: Research and Methods of Computational Finance for Measuring Risk of Financial Instruments},
author={Lamjed Ben Siad and Zahra Kodia and Khaled Ghédira},
isbn={9781627345033},
url={https://books.google.tn/books?id=lO6VBAAAQBAJ},
year={2014},
publisher={Universal-Publishers.com}
}
BibTeX
@article{fathali2022stock,
title={Stock market prediction of Nifty 50 index applying machine learning techniques},
author={Fathali, Zahra and Kodia, Zahra and Ben Said, Lamjed},
journal={Applied Artificial Intelligence},
volume={36},
number={1},
pages={2111134},
year={2022},
publisher={Taylor \& Francis}
}
BibTeX
@article{kodia2011simulation,
title={Simulation comportementale {\`a} base d'agents de la dynamique du march{\'e} boursier: Mod{\`e}le cognitif de l'investisseur},
author={Kodia, Zahra and Said, Lamjed Ben and Gh{\'e}dira, Khaled},
journal={Revue d'intelligence artificielle},
volume={25},
number={1},
pages={83--107},
year={2011}}



Zakia Zouaghia