Academic & Scientific Articles

Permanent URI for this community

http://dl.cerist.dz/handle/CERIST/3

Browse

Now showing 1 - 20 of 694

A Novel Approach to Preserving Privacy in Social Network Data Publishing
(CERIST, 2016-10-24) Bensimessaoud, Sihem; Benmeziane, Souad; Badache, Nadjib; Djellalbia, Amina
Today, more and more social network data are published for data analysis. Although this analysis is important, these publications may be targeted by re-identification attacks i.e., where an attacker tries to recover the identities of some nodes that were removed during the anonymization process. Among these attacks, we distinguish "the neighborhood attacks" where an attacker can have background knowledge about the neighborhoods of target victims. Researchers have developed anonymization models similar to k-anonymity, based on edge adding, but can significantly alter the properties of the original graph. In this work, a new anonymization algorithm based on the addition of fake nodes is proposed, which ensures that the published graph preserves another important utility that is the average path length “APL”.
A basic platform of collaborative filtring
(CERIST, 2008) Nouali, Omar; Kirat, Sabah; Meziani, Hadjer
With the explosive growth of the quantity of new information the development of information systems to target the best answers provided to users, so they are closer to their expectations and personal taste, has become an unavoidable necessity. The collaborative filtering systems are among these information systems with particular characteristics that make the difference. The term refers to collaborative filtering techniques using the familiar tastes of a group of users to predict the unknown preference of a new user. This article describes a basic platform of collaborative filtering, which allows users to discover interesting documents, through automation of the natural process of recommendation, it allows them to express their opinion about the relevance of documents, according to their tastes and documents’ quality they perceive; it offers the opportunity to benefit from the evaluations on documents of other users, with similar profile, have found interesting. All these benefits are provided to users by the principle of collaboration, in return for an individual effort: evaluating documents.
A causal multicast protocol for dynamic groups in cellular networks
(ACM, 2008-09-10) Benzaid, Chafika; Badache, Nadjib
Group communication is an abstraction which deals with multicasting a message from a source process to a group of processes. In Group Communication Systems (GCS), causal message ordering is an essential tool to ensure interaction among group members in a consistent way. In this paper, we propose a simple and optimal causal multicast protocol which copes with the dynamically changing groups in mobile environments. The protocol presents an optimal communication overhead without causing inhibition effect in the delivery of messages. The group membership management depends on a simple, yet powerful idea. This original idea consists in considering the join and leave requests as data messages, and then will be ordered with other messages. This makes no need to a coordination phase in the installation of a new view. Our protocol requires minimal resources on mobile hosts and wireless links and scales well with large groups.
A Classification-based XML Information Retrieval Model
(CERIST, 2014-11-27) Bessai, Fatma-Zohra
The main problem of content-based XML information retrieval is how to select the relevant unit of information that answers the user’s query composed of only key words (content only). Our objective is to select relevant elements that can belong to different parts of XML documents of the corpus for user’s information need. To do this, we propose a neural XML information retrieval model using Kohonen self-organizing maps. Kohonen self-organizing map lets classification of XML elements producing density map that form the foundations of the XML information retrieval system.
A Clustering Application for the Web Usage Mining
(CERIST, 2012-12) Kouici, Salima
The Web Usage Mining constitutes a new branch of the Web Mining. It allows the study of the behavior of both users and potential customers via their site navigation. The mainly used source for the Web Usage Mining is the servers Log Files. A Log File contains an important mass of data, including user’s information (username, used software, etc.) and all the queries he has made on the website (requested files, the number of bytes transferred, time spent on each page, the page of entry to the site .... etc.). In this work we shall outline an application, made on this type of data, which is based on a clustering method, namely KMEANS. This application allows the definition of homogeneous groups constituting users profiles so that to anticipate the needs and with a view of communication adapted to each segment of users. In this application we have recorded some technical problems. These problems concerns the data cleaning (removing queries of images and multimedia files associated with web pages, removing queries from search bots... etc.) and the setting up of visitor sessions, knowing that a session is a sequence of pages viewed by the same user.
A Clustering application for the Web Usage Mining.
(Pushpa Publishing House, 2013-07) Kouici, Salima; Khelladi, Abdelkader
The web usage mining constitutes a new branch of the web mining. It allows the study of the behavior of both users and potential customers via their site navigation. The mainly used source for the web usage mining is the servers log files. A log file contains an important mass of data, including user’s information (username, used software, etc.) and all the queries he has made on the web site (requested files, the number of bytes transferred, time spent on each page, the page of entry to the site, etc.). In this work, we shall outline an application made on this type of data, which is based on a clustering method, namely K-means. This application allows the definition of homogeneous groups constituting users’ profiles so that to anticipate the needs and with a view of communication adapted to each segment of users. In this application, we have recorded some technical problems. These problems concern the data cleaning (removing queries of images and multimedia files associated with web pages, removing queries from search engines, etc.) and the setting up of visitor sessions, knowing that a session is a sequence of pages viewed by the same user.
A clustering technique to analyse anonymous systems
(CERIST, 2014-07-20) Benmeziane, Souad; Badache, Nadjib
Concerns about privacy and anonymity have gained more and more attention in conjunction with the rapid growth of the Internet as a means of communication and information dissemination. A number of anonymous communication systems have been developed to protect the identity of communication participants. Nevertheless, it is important to provide ways to evaluate and measure the level of anonymity provided. We introduce in this report the use of hierarchical clustering technique to analyse anonymous systems. We propose a new measure to evaluate anonymous systems by introducing the concept of dominant cluster. We further show that using this measure will overcome the limitations of other existing measures.
A clustering technique to analyse anonymous users.
(CPS, 2014-08-09) Benmeziane, Souad; Badache, Nadjib
Concerns about privacy and anonymity have gained more and more attention in conjunction with the rapid growth of the Internet as a means of communication and information dissemination. A number of anonymous communication systems have been developed to protect the identity of communication participants. Nevertheless, it is important to provide ways to evaluate and measure the level of anonymity provided. We introduce in this paper the use of hierarchical clustering technique to analyse anonymous systems. We propose a new measure to evaluate anonymous systems by introducing the concept of dominant cluster. We further show that using this measure will overcome the limitations of other existing measures.
A Communication model of distributed information sources bacteria colonies inspired
(IEEE, 2006) Mellah, Hakima; Hassas, Salima; Drias, Habiba
The implementation of communication organizational strategies constitutes an essential performance factor. Nowadays, the organization becomes companies competitiveness element (organizational structures), networks, knowledge and competences management, and cooperation. This, to be better reactive to ensure the competing character, to support better new information technologies, concerning the data exchange inside as outside an organization. The information systems specification gives a partial description of the organization, which integrated with other descriptions is regarded as being the organization model. Using the abstraction level of an information system (information source) was proven to be not sufficient to face the conflicts confronted by the organizations. These conflicts are the improvement and the change with an aim of adapting constantly to the environment new requirements. These latter are essential to support the dynamic character which tends to characterize the current organizations and which is often nature taken. In order to implement this dynamism, we took as a starting point the biological sciences and more particularly the bacteria colonies. This paper presents a correspondence model between a communication system of distributed information sources and a bacteria colony
A comparative study between compressed video watermarking methods based on DCT coefficients and intra prediction
(2011-04-20) Bouchama, Samira; Hamami, Latifa; Aliane, Hassina
Several watermarking methods have been applied to the newest video codec H.264/AVC to satisfy different applications such as authentication, tamper proof and copyright protection. Our objective through this paper is to present a comparative study between watermarking methods based on the quantized (Q) DCT coefficients and those based on the intra prediction of the 4x4 luma blocks, in terms of embedding capacity, video quality and bitrate. The use of intra prediction modes is motivating because it is possible to embed a relatively high embedding capacity while preserving the video quality; however it seems difficult to maintain the bitrate. In this paper we show that the Intra prediction based method outperforms the QDCT based method using the same codec configuration.
A comparative study between compressed video watermarking methods based on DCT coefficients and intra prediction
(CERIST, 2011-09) Bouchama, Samira; Hamami, Latifa; Aliane, Hassina
Several watermarking methods have been applied to the newest video codec H.264/AVC to satisfy different applications such as authentication, tamper proof and copyright protection. Our objective through this paper is to present a comparative study between watermarking methods based on the quantized (Q) DCT coefficients and those based on the intra prediction of the 4x4 luma blocks, in terms of embedding capacity, video quality and bitrate. The use of intra prediction modes is motivating because it is possible to embed a relatively high embedding capacity while preserving the video quality; however it seems difficult to maintain the bitrate. In this paper we show that the Intra prediction based method outperforms the QDCT based method using the same codec configuration.
A Concise Forwarding Information Base for Scalable and Fast Name Lookups
(IEEE, 2017-11-30) Yu, Ye; Belazzougui, Djamal; Qian, Chen; Zhang, Qin
Forwarding information base (FIB) scalability and its lookup speed are fundamental problems of numerous net- work technologies that uses location-independent network names. In this paper we present a new network algorithm, Othello Hashing, and its application of a FIB design called Concise, which uses very little memory to support ultra-fast lookups of network names. Othello Hashing and Concise make use of minimal perfect hashing and relies on the programmable network framework to support dynamic updates. Our conceptual contribution of Concise is to optimize the memory efficiency and query speed in the data plane and move the relatively complex construction and update components to the resource- rich control plane. We implemented Concise on three platforms. Experimental results show that Concise uses significantly smaller memory to achieve much faster query speed compared to existing solutions of network name lookups.
A cooperative framework for automated segmentation of tumors in brain MRI images
(Springer, 2023-03) Hadjadj, Zineb
Brain tumor segmentation from 2D Magnetic Resonance Images (MRI) is an important task for several applications in the field of medical analysis. Commonly, this task is performed manually by medical professionals, but it is not always obvious due to similarities between tumors and normal tissue and variations in tumor appearance. Therefore, the automation of medical image segmentation remains a real challenge that has attracted the attention of several researchers in recent years. Instead of choosing between region and contour approaches, in this article, we propose a region-edge cooperative method for brain tumor segmentation from MRI images. The region approach used is support vector machines (SVMs), one of the popular and highly motivated classification methods, the method distinguishes between normal and abnormal pixels based on some features: intensity and texture. To control and guide the segmentation region, we take advantage of the Ron Kimmel geodesic Active Contour Model (ACM) which produces a good delimitation of the boundaries of the object. The two methods have been cooperated sequentially in order to obtain a flexible and effective system for brain tumor segmentation. Experimental studies are performed on synthetic and real 2D MRI images of various modalities from the radiology unit of the university hospital center in Bab El Oued Algeria. The used MRI images represent various tumor shapes, locations, sizes, and intensities. The proposed cooperative framework outperformed SVM-based segmentation and ACM-based segmentation when executed independently.
A critical review of quality of service models in mobile ad hoc networks
(Inderscience Enterprises Ltd, 2019) Bouchama, Nadir; Aïssani, Djamil; Djellab, Natalia; Nouali-Taboudjemat, Nadia
Quality of service (QoS) provisioning in mobile ad hoc networks (MANETs) consists of providing a complex functionality in a harsh environment where resources are scarce. Thus, it is very challenging to build an efficient solution to address this issue. The proposed solutions in the literature are broadly classified into four categories, namely: QoS routing protocols, QoS signalling, QoS-aware MAC protocols and QoS models, which are the main concern of our study. The contribution of this paper is threefold: Firstly, we propose a set of guidelines to deal with the challenges facing QoS models design in ad hoc networks. Secondly, we propose a new taxonomy for QoS models in ad hoc networks. Finally, we provide an in-depth survey and discussion of the most relevant proposed frameworks.
A distributed mutual exclusion algorithm over multi-routing protocol for mobile ad hoc networks
(Taylor et Francis, 2008-04-15) Derhab, Abdelouahid; Badache, Nadjib
In this paper, we propose a new architecture to solve the problem of mutual exclusion in mobile ad hoc networks (MANET). The architecture is composed of two layers: (i) a middleware layer that contains a token-based distributed mutual exclusion algorithm (DMEA) and (ii) a network layer that includes two routing forwarding strategies: one to route request messages and the other to route the token message. We also propose a request ordering policy that ensures the usual mutual exclusion properties and reduces the number of hops traversed per critical section (CS) access. The paper also addresses the problem of network partitioning and unreachable nodes. The proposed mutual exclusion algorithm is further enhanced to provide fault tolerance by preventing the loss of the token and generating a new token if the token loss event occurs. The performance complexity as well as the experimental results show that the proposed algorithm experiences low number of hops per CS access.
A fault tolerant services discovery by self organisation: a MAS approach.
(Inderscience, 2013) Mellah, Hakima; Hassas, Salima; Drias, Habiba
The service discovery has become an emerging phenomena in software engineering and process engineering as well. The paper presents a multi agent system (MAS) approach, for service discovery process, based on a self-organising protocol. This feature is very crucial for assuring a correct service delivery, to avoid failures or mal-function for the service discovery environment. The requirement for self-organising choreographed services have been well realised, in case of operational, functional and behavioural faults. The self-organising protocol is conceived from bacteria colony.
A flexible distance for the spatial placement in a multimedia document
(Institute of Electrical and Electronics Engineers ( IEEE ), 2008-04-07) Maredj, Azze-Eddine; Tonkin, Nourredine; Sadallah, Madjid; Alimazighi, Zaia
In the multimedia documents authoring systems the management of spatial and temporal inter-objects relations is the most delicate task. Spatial relations management refers to the appropriate means to express relations between the document objects and guarantee their consistency. Usually it is represented by spatial model which performances depend on its expressivity degree, on its positioning precision and on the ability to express a desired overlap. One of the most important factor that affects performnaces is the distance associated to the relations. To enhance the expressivity and precision degrees and to allow the specification of desired overlap, we introduce, in this paper, the flexible distance concept.
A formal approach for a self organizing protocol: Production System application
(CERIST, 2009-10) Mellah, Hakima; Drias, Habiba; Hassas, Salima
Any dysfunction in production system (PS) is likely to be very expensive; so modelling by Multi Agent Systems (MAS) makes the production system (PS) possible to have aspects of robustness, reactivity and flexibility, which allow the PS control to be powerful and to react to all the risks being able to occur. In order to have a fault-tolerant PS, we propose when and how to recourse to a self organizing protocol making the MAS capable of changing its communication structure or organization, and thus reorganizing itself without any external intervention.
A formal model for output multimodal HCI
(Springer Vienna, 2015-07) Mohand Oussaïd, Linda; Ait Sadoune, Idir; Ait Ameur, Yamine; Ahmed-Nacer, Mohamed
Multimodal human–computer interaction (HCI) combine modalities at an abstract specification level in order to get information from the user (input multimodality) and to return information to the user (output multimodality). These multimodal interfaces use two mechanisms: first, the fusion of information transmitted by the user on different modalities during input interaction and second, the fission or decomposition of information produced by the functional core in order to distribute the composite information on the different modalities during output interaction. In this paper, we present a generic approach to design output multimodal interfaces. This approach is based on a formal model, composed of two models: semantic fission model for information decomposition process and allocation model for modalities and media allocation to composite information. An Event-B formalization has been proposed for the fission model and for allocation model. This Event-B formalization extends the generic model and support the verification of some relevant properties such as safety or liveness. An example of collision freeness property verification is presented in this paper.
A framework for Object Classification in Fareld Videos
(Springer, 2014-12) Setitra, Insaf; Larabi, Slimane
Object classification in videos is an important step in many applications such as abnormal event detection in video surveillance, traf- fic analysis is urban scenes and behavior control in crowded locations. In this work, propose a framework for moving object classification in farfield videos. Much works have been dedicated to accomplish this task. We overview existing works and combine several techniques to implement a real time object classifier with offline training phase. We follow three main steps to classify objects in steady background videos : background subtraction, object tracking and classification. We measure accuracy of our classifier by experiments done using the PETS 2009 dataset.

Browse

Browsing Academic & Scientific Articles by Title

Results Per Page

Sort Options