It is widely acknowledged that image denoising problem has been studied in the areas of image processing. The denoising problem is to recover original image u from the observed image f . In this paper, l 1 and l 2 -norm regularization are
studied, developed and implemented in order to restore images contaminated by additive noise. To solve these two approaches problems, the discretization finite difference method is employed before applying the gradient descent
algorithm to optimize the noised signal. According to experiment results, the two methods are applied to some test images with different level noise then compared by using the quality metrics Signal Noise to Ratio SNR , Peak-Signal-to-Noise-Ratio(PSNR) and Structural Similarity Index(SSIM). Through this study, the algorithm which minimizes l 2 – norm of gradient of image has a unique solution and it’s easy to implement, but it doesn’t accept contour discontinuities, causing the obtained solution to be smooth. The l 2 -norm will blur the edges of the image. In order to preserve sharp edges, l 1 -norm is introduced. So, we can confirm that l 1 regularization encourages image smoothness while allowing for presence of jumps and discontinuities, a key feature for image processing because of the importance of edges in human
vision.

Auteurs : Nacira Diffellah , Rabah Hamdini  , Tewfik Bekkouche

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Internet of Multimedia Things (IoMT) is one extensively current topic of the Internet of Things (IoT) due to the immersive growth of multimedia applications in several fields. In Low-power and Lossy Networks (LLNs) where sensor nodes are a key component, providing a satisfactory quality of service (QoS) as well as a user quality of experience (QoE) for such applications is a challenging task. In fact, high bandwidth and substantial computation resources are required. To provide sufficient bandwidth to handle these high data rate applications, we propose to extend RPL to enable for simultaneous use of disjoint multiple paths. This is done on top of the already maintained DODAG structure with the least induced overhead. Furthermore, we suggest applying a low-complexity encoding method on the captured images. Based on both QoS and QoE metrics, we evaluate the performance of our disjoint multipath RPL (DM-RPL) for real video clip transmission using the IoT-LAB testbed. Our results show that multipath provides more bandwidth as the
PDR is increased. Video quality is further improved thanks to the adopted data reduction at the source. All of this translates into less energy being consumed.

Auteurs : Souhila Kettouche  , Moufida Maimour , Lakhdar Derdouri

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Image ortho-rectification is a standard process in remote sensing for correcting the geometric distortions and relief displacement errors introduced by the payload system during the imaging time. It requires a precise rigorous sensor model or rational function models which are refined using well-distributed ground control points. The Rational function model (RFM) is commonly used because of its simplest model and does not need sensor parameters. Therefore, the RFM terms or also rational polynomial coefficients (RPCs) have no physical significance but depends on many ground control points (GCPs) that make the model prone to the over parameterization problem. The application of meta-heuristic algorithms is suited for RFM optimization. This paper proposes a binary particle swarm optimization BPSO to surmount the issue of
over-parameterization and find the optimum combination of RPCs for the RFM by adding a new transfer function. The algorithm is applied to the ALSAT2 images and the results showed the effectiveness and the accuracy of BPSO over the traditional binary literature methods. Furthermore, a hybrid optimization technique is introduced that blends the BPSO concept by adding the genetic operations such as crossover and mutation in order to increase the convergence speed and avoid the local optimum phenomenon. The proposed method gives a better result than the suggested one.

Auteurs : Oussama Mezouar , F. Meskine  , I. Boukerch

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Mobile Ad hoc networks attract more attention over the years, but the security matter of this type of network makes it hard  to achieve all of their advantages. Cryptographic key management is the cornerstone for building any robust network  security solution. Identity-based cryptography is a promising solution that resists well the key escrow problem, which is  suitable for Mobile Ad hoc networks. In this paper, we give an overview of the most important identity-based encryption  schemes proposed in the last decade; combined with other techniques to enhance it and provide better results for Mobile  Ad hoc networks. Hence, we give a comparative analysis to highlight their advantages and weaknesses. This work gives  insights into a recent research to point out its interesting features, take advantages of its strength, ovoid its weaknesses and  to lay out the future directions in this area.

Auteurs : Kenza Gasmi, Abdelhabib Bourouis, Rohallah Benaboud

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Special issue of  The 2nd International Conference on Computer Science’s Complex Systems and their  Applications (ICCSA’2021) .

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In this « special issue » on the topic « From Data and Information Processing to Knowledge Organization: Architectures,Models and Systems », seven (07) selected communications have been reviewed by peers in the OCTA Multi-Conference (unifying 4 scientific projects: SIIE, ISKO-Maghreb, CITED and TBMS) in program committees. We consider that this set of proposals, enriched in circumstance of this special issue by its authors at our request, are an excellent engine of current scientific ideas and challenges in the domain concerned in ISKO-Maghreb Society.

Auteur : Sahbi Sidhom

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We intend in this paper to outline one part of the number theory genesis relatively to the equation: a square plus/minus a number equals a square focusing on the Arabic mathematicians’ works, like, for example, those of al-Khazin, Ibn al-Laith, al-Karaji, al-Baghdadi and al-Khallat. We will then briefly describe the occidental tradition relative to his subject threw the works of Fibonacci, Fermat, Frenecle, Euler, and others.

Auteurs : Khaled Kchir, Saif-Eddin Toumi, Foued Nafti

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Today, the world is affected by a new concept of war called terrorism. As plans to face conventional enemies have become unusual against terrorism, there are a necessity for innovative concepts and technologies. In order to support units,  we aim to upgrade the capability of leaders structuring their choices. In this paper, we offer a multi-agent architecture for the planning of actions against terrorist attacks. It is distinguished by decisive policy responses and methodical procedures for managing the situation, as well as by the flexibility to adapt a contingency scenario. We describe the relationship between actors during a terrorist attack in order to establish the best possible distribution of units to  neutralize the enemy.

Auteurs : Oussama Kebir, Issam Nouaouri, Mouna Belhaj, Lamjed Ben Said, Kamel Akrout

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Through this study, we propose an overview of two decades of research on Strategic Environmental Scanning (ESS) and competitive intelligence (CI) in Tunisia. A particular attention is given to Scientific and Technical Scanning (STS) as part of SES practices and as a strong support to R&D activity and  trigger of innovation. The objective of this work is to fill a gap faced by academic researchers interested in issues related to this field of research. The scarcity of meta-analyses within the literature review and retrospective studies could be an obstacle to the cumulative nature of the research and the
capitalization of actionable knowledge from the various investigations.

Auteurs : Souad Kamoun Chouk, Maroua Hammami

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Different diffusion tools within collaborative networks provide to researchers more and recent information.

In this paper, we focus on the scientific quality of diffused information and discuss the implications of this tendency for scientific performance. We propose a qualitative scientific watch system enriched by an alerts’ personalization and cartographic visualization tools.

The proposed watch system is based on scientific quality evaluation in its different parts. Scientific quality evaluation is made by the mean of scientometric indicators to select qualitative new publications to diffuse to the
researchers. The integration of personalization tool helps researchers on identifying qualitative information which corresponds to their needs. Moreover, the cartographic visualization provides to the researchers the possibility of analyzing and choosing more quickly interesting and useful alerts.

Auteurs : Nedra Ibrahim, Anja Habacha Chaibi, Henda Ben Ghézala

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