Publications

  • 2023
    Ilhem Souissi, Rihab Abidi, Nadia Ben Azzouna, Tahar Berradia, Lamjed Ben Said

    ECOTRUST: A novel model for Energy COnsumption TRUST assurance in electric vehicular networks

    Ad Hoc Networks, 149, 103246., 2023

    Abstract

    Electric Vehicles (EVs) emerged new kinds of applications that strongly depend upon the energy information such as identifying the optimal path towards the vehicle’s destination where the EV maximizes the recovered electrical power, displaying the energetic map that provides an overview about the required energy consumption on each lane, etc. The quality of these applications relies on the reliability of the vehicle-related information (e.g. location, energy consumption). EVs may provide wrong energy information due to sensors’ failure, selfish or malicious reasons. To this aim, a fuzzy-based energy consumption trust (ECOTRUST) model is proposed herein to evaluate the quality of energy information based on two fuzzy inference systems: Instant Energy Trust (IEN-Trust) and Total Energy Trust (TEN-Trust) systems. IEN-TRUST relies on a series of plausibility checks to evaluate the coherence between the reported energy information and other parameters (slope degree, speed and acceleration rate) while TEN-TRUST relies on the similarity between neighbouring vehicles. The performance of the ECOTRUST model is evaluated in terms of the system’s robustness and accuracy under different traffic intensities. We varied the traffic volume and the percentage of malicious vehicles and their behaviours. Results show that IEN-TRUST is resilient to false messages with/without the collusion attack. However, it is unable to deal with complex behaviours of malicious vehicles (e.g. on-off attack, bush telegraph). TEN-TRUST was proposed to deal with the latter issue. Simulation results show that it can accurately deal with complex behaviours in different traffic volumes.
    Rihab Abidi, Nabil Sahli, Nadia Ben Azzouna, Wassim Trojet, Ghaleb Hoblos

    Monitoring Traffic Congestion Using Trust-Based Smart Road Signs

    In: Klein, C., Jarke, M., Ploeg, J., Berns, K., Vinel, A., Gusikhin, O. (eds) Smart Cities, Green Technologies, and Intelligent Transport Systems. SMARTGREENS VEHITS 2023 2023. Communications in Computer and Information Science, vol 1989. Springer, Cham., 2023

    Abstract

    The evolution of Intelligent Transportation Systems (ITSs) enabled the emergence of traffic management applications, with the aim to enhance the traffic flow and ease the congestion by monitoring the traffic. However, the efficiency of these applications resides on the accuracy of the shared traffic information. Accordingly, trust management models are applied to secure the Vehicular Ad-hoc NETwork (VANET) and to assess the reliability of the data shared within the vehicular network. In this paper, we propose a proof-of-concept of the trust framework proposed in . The main objective is to observe the utility of applying trust management models to the intelligent transportation systems. The simulation results show that deploying trust-based Smart Road Signs (SRSs) helps to alleviate the traffic congestion around junctions by displaying the traffic state to users and offering them the opportunity to take alternative roads.
    Besma Ben Amara, Hédia Sellemi, Lamjed Ben Said

    An Approach for Serious Games Requirements Specification based on Design Challenges and Characteristics Taxonomy

    Multi-Conference OCTA'2023., 2023

    Abstract

    As in software development projects, the most critical activity in
    Serious Game (SG) design process is the requirements specification due to SG's
    multidisciplinary and characteristics complexity. In the literature, specific
    design methodologies with requirements specification strategies are still needed
    to achieve an engaged SG. This paper proposes an approach that assists
    designers and design stakeholders when specifying required SG features and
    their relationships. We shaped this approach into three stages with three
    abstraction levels based on both characteristics taxonomy model and the SG
    design challenges we propose in this work. We practiced the proposed process
    in specifying an SG for health safety environment training for workers in fuel
    storage sites. The feedback shows that such a strategy would be highly
    beneficial for the participatory design process since it reduces game features'
    complexity and thus their understanding by the design team members. It also
    promotes game design artifacts evaluation and allows effective processing of
    the game requirement changes.

    Nabil Morri, Sameh Morri, Hadouaj, Lamjed Ben Said

    Fuzzy logic based multi-objective optimization of a multi-agent transit control system.

    Memetic Comp. 15, 71–87 (2023)., 2023

    Abstract

    This paper models a transit control system for the management of traffic perturbations of public transport. The transit system data is voluminous and highly dynamic. Moreover, the transit domain has a remarkable lack of intelligent systems to monitor and maintain better performance. Consequently, realizing an intelligent transit control system has become a consistent need. The modeling of the system addresses a problem of optimizing performance measures based on key performance indicators. Its objective is to find the optimal control action in disturbance cases. The solution consists in combining all performance measures in a single measure by using fuzzification without neglecting the space and time requirements of the traffic. To model and implement our system we used a multi-agent approach. The experiments performed were based on real network traffic data. The obtained results demonstrate the relevance of the proposed fuzzy approach in our optimization problem and show the advantage of the multi-agent system in the modeling of our control system. We prove that the proposed control system achieves better results than certain existing fuzzy approaches and is able to manage disturbances with a better performance than the existing solutions.

    Riadh Ghlala, Zahra Kodia, Lamjed Ben Said

    Using MCDM and FaaS in Automating the Eligibility of Business Rules in the Decision-Making Process

    The International Arab Journal of Information Technology 20(2), 2023

    Abstract

    Serverless Computing, also named Function as a Service (FaaS) in the Azure cloud provider, is a new feature of cloud computing. This is another brick, after managed and fully managed services, allowing to provide on-demand services instead of provisioned resources and it is used to strengthen the company’s ability in order to master its IT system and consequently to make its business processes more profitable. Knowing that decision making is one of the important tasks in business processes, the improvement of this task was the concern of both the industry and the academy communities. Those efforts have led to several models, mainly the two Object Management Group (OMG) models: Business Process Model and Notation (BPMN) and Decision Model and Notation (DMN) in order to support this need. The DMN covers the decision-making task in business processes mainly the eligibility of business rules. This eligibility can be automated in order to help designers in the mastering of this important task by the running of an algorithm or a method such as the Multiple Criteria Decision Making (MCDM). This feature can be designed and implemented and deployed in various architectures to integrate it in existing Business Process Management Systems (BPMS). It could then improve supporting several business areas such as the Business Intelligence (BI) process. In this paper, our main contribution is the enrichment of the DMN model by the automation of the business rules eligibility through Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) using FaaS to further streamline the decision-making task in business processes. Results show to strengthen business-IT alignment and reduce the gap between the real world and associated IT solutions.

    Imen Oueslati, Moez Hammami, Issam Nouaouri, Ameni Azzouz, Lamjed Ben Said, Hamid Allaoui

    A Honey Bee Mating Optimization HyperHeuristic for Patient Admission Scheduling Problem

    In proceedings of The 9th International Conference on Metaheuristics and Nature Inspired Computing META Marrakech, Nov 01-04, 2023, 2023

    Abstract

    Hyperheuristics represent a generic method that provides a high level of abstraction, enabling solving several problems in the combinatorial optimization domain while reducing the need for human intervention in parameters tuning. This category consists in managing a set of low-level heuristics and attempting to find the optimal sequence that produces high-quality results. This paper proposes a hyperheuristic that simulates the honey bees mating behavior called “Honey bee Mating Optimization HyperHeuristic”  to solve the Patient Admission Scheduling Problem (PASP). The PASP is an NP-hard problem that represents an important field in the health care discipline. In order to perceive the influence of low-level heuristics on the model’s performance, we implemented two versions of the hyperheuristic that each one works on a different set of low-level heuristics. The results show that one of the versions generates better results than the other, revealing the important role of low-level heuristics’ quality leading to enhancing the hyperheuristic performance.

    Rihab Abidi, Nabil Sahli, Wassim Trojet, Nadia Ben Azzouna, Ghaleb Hoblos

    An Infrastructure-Based Trust Management Framework for Cooperative ITS.

    In VEHITS (pp. 329-336)., 2023

    Abstract

    Intelligent Transportation Systems (ITSs) have been exploited by developed countries to enhance the quality of transportation services. However, these systems are still facing major bottlenecks to be addressed such as the data density, precision and reliability of perceived data and computational feasibility of the nodes. Trust management is a mechanism applied to secure the vehicular networks. However, most of the proposed trust models that are applied to Vehicular Ad-hoc NETwork (VANET) do not address all the aforementioned challenges of ITS. In this paper, we present a comprehensive framework of trust management specifically designed for ITS applications. The proposed framework is an infrastructure-based solution that relies on Smart Road Signs (SRSs) to assess the trustworthiness of traffic data and nodes of the network. The idea of the framework is to use autonomous SRSss that are able to collect raw data and evaluate it in order to alert the drivers with reliable traffic information in real time. We adopt a hierarchical architecture that exploits a two-level trust evaluation to ensure accuracy, scalability, security and high reactivity of ITS applications. A discussion of the framework and its strengths is presented.
    Zakia Zouaghia, Zahra Kodia, Lamjed Ben Said

    Hybrid machine learning model for predicting NASDAQ composite index

    2023 International Symposium on Networks, Computers and Communications (ISNCC), Doha, Qatar, 2023, pp. 1-6, 2023

    Abstract

    Financial markets are dynamic and open systems. They are subject to the influence of environmental changes. For this reason, predicting stock market prices is a difficult task for investors due to the volatility of the financial stock markets nature. Stock market forecasting leads investors to make decisions with more confidence based on the prediction of stock market price behavior. Indeed, a lot of analysts are greatly focused in the research domain of stock market prediction. Generally, the stock market prediction tools are categorized into two types of algorithms: (1) linear models like Auto Regressive (AR), Moving Average (MA), Auto-Regressive Integrated Moving Average (ARIMA), and (2) non-linear models like Autoregressive Conditionally Heteroscedastic (ARCH), Generalized Autoregressive Conditional Heteroskedasticity (GARCH) and recently Neural Network (NN)). This paper aspires to crucially predict the stock index movement for National Association of Securities Dealers Automated Quotations (NASDAQ) based on deep learning networks. We propose a hybrid stock price prediction model using Convolutional Neural Network (CNN) for feature selection and Neural Network models to perform the task of prediction. To evaluate the performance of the proposed models, we use five regression evaluation metrics: Root Mean Square Error (RMSE), Mean Square Error (MSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE) and R-Square (R2), and the Execution Time (ET) metric to calculate the necessary time for running each hybrid model. The results reveal that error rates in the CNN-BGRU model are found to be lower compared to CNN-GRU, CNN-LSTM, CNN-BLSTM and the the existing hybrid models. This research work produces a practical experience for decision makers on financial time series data.

    Zakia Zouaghia, Zahra Kodia, Lamjed Ben Said

    Stock movement prediction based on technical indicators applying hybrid machine learning models

    2023 International Symposium on Networks, Computers and Communications (ISNCC), Doha, Qatar, 2023, pp. 1-4, 2023

    Abstract

    The prediction of stock price movements is one of the most challenging tasks in financial market field. Stock price trends depended on various external factors like investor’s sentiments, health and political crises which can make stock prices more volatile and chaotic. Lately, two crises affected the variation of stock prices, COVID-19 pandemic and Russia-Ukraine conflict. Investors need a robust system to predict future stock trends in order to make successful investments and to face huge losses in uncertainty situations. Recently, various machine learning (ML) models have been proposed to make accurate stock movement predictions. In this paper, a framework including five ML classifiers (Gaussian Naive Bayes (GNB), Random Forest (RF), Gradient Boosting (GB), Support Vector Machine (SVM), and K-Nearest Neighbors (kNN))) is proposed to predict the closing price trends. Technical indicators are calculated and used with historical stock data as input. These classifiers are hybridized with Principal Component Analysis method (PCA) for feature selection and Grid Search (GS) Optimization Algorithm for hyper-parameters tuning. Experimental results are conducted on National Association of Securities Dealers Automated Quotations (NASDAQ) stock data covering the period from 2018 to 2023. The best result was found with the Random Forest classifier model which achieving the highest accuracy (61%).

    Mouna Karaja, Abir Chaabani, Ameni Azzouz, Lamjed Ben Said

    Dynamic bag-of-tasks scheduling problem in a heterogeneous multi-cloud environment: a taxonomy and a new bi-level multi-follower modeling

    Journal of Supercomputing,1-38, 2023

    Abstract

    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.