Intrusion detection mechanisms for VoIP applications

VoIP applications are emerging today as an important component in business and communication industry. In this paper, we address the intrusion detection and prevention in VoIP networks and describe how a conceptual solution based on the Bayes inference approach can be used to reinforce the existent security mechanisms. Our approach is based on network monitoring and analyzing of the VoIP-specific traffic. We give a detailed example on attack detection using the SIP signaling protocol

Psychological empowerment and organisational change among hotel employees in Egypt

Empowering employees can have a significant impact on increasing job satisfaction, efficiency and productivity in the hotel industry. This paper aims to investigate the effect of empowerment on readiness for and acceptance of organisational changes among employees in Egyptian chain hotels. The study used a survey questionnaire to examine psychological empowerment across four dimensions (meaning, competence, self-determination, and impact) and readiness for change. Data were collected from 386 employees in chain hotels in Egypt, and the relationships between variables were examined using correlation and multiple regression analysis. The results show that there were no correlations between acceptance of change and any individual dimension of psychological empowerment. However, the regression analysis shows that psychological empowerment had a slight, but significant, positive effect on acceptance of organisational change. The overall model explained 2.7% of the variance in organisational change. Both “meaning” and “impact” constructs were significant, although “meaning” had a slight negative effect. These findings suggest that hotel managers should consider the effect of psychological empowerment when preparing for organisational change, although this is only one factor which should be taken into account.Keywords: psychological empowerment, organisational change, hospitality industry, Egyp

Fault-tolerant interconnection networks for multiprocessor systems

Interconnection networks represent the backbone of multiprocessor systems. A failure in the network, therefore, could seriously degrade the system performance. For this reason, fault tolerance has been regarded as a major consideration in interconnection network design. This thesis presents two novel techniques to provide fault tolerance capabilities to three major networks: the Baseline network, the Benes network and the Clos network. First, the Simple Fault Tolerance Technique (SFT) is presented. The SFT technique is in fact the result of merging two widely known interconnection mechanisms: a normal interconnection network and a shared bus. This technique is most suitable for networks with small switches, such as the Baseline network and the Benes network. For the Clos network, whose switches may be large for the SFT, another technique is developed to produce the Fault-Tolerant Clos (FTC) network. In the FTC, one switch is added to each stage. The two techniques are described and thoroughly analyzed

Throttling Malware Families in 2D

Malicious software are categorized into families based on their static and dynamic characteristics, infection methods, and nature of threat. Visual exploration of malware instances and families in a low dimensional space helps in giving a first overview about dependencies and relationships among these instances, detecting their groups and isolating outliers. Furthermore, visual exploration of different sets of features is useful in assessing the quality of these sets to carry a valid abstract representation, which can be later used in classification and clustering algorithms to achieve a high accuracy. In this paper, we investigate one of the best dimensionality reduction techniques known as t-SNE to reduce the malware representation from a high dimensional space consisting of thousands of features to a low dimensional space. We experiment with different feature sets and depict malware clusters in 2-D. Surprisingly, t-SNE does not only provide nice 2-D drawings, but also dramatically increases the generalization power of SVM classifiers. Moreover, obtained results showed that cross-validation accuracy is much better using the 2-D embedded representation of samples than using the original high-dimensional representation

Characterization of aggresome formation in choroid plexus carcinoma.

Protein misfolding is inevitable, 30% of newly synthesized polypeptides can end up misfolded, and such proteins are either refolded or eliminated by cellular quality control pathways. These pathways include the ubiquitin proteosome system and autophagy. In recent years, protein misfolding has been implicated in the pathophysiology of many diseases such as diabetes, neurological disorders and cancer. Studies from our laboratory have shown that choroid plexus carcinoma tumors are characterized by the formation of aggresomes at the microtubules organizing centers (MTOC) in formalin fixed and paraffin embedded (FFPE) tumor tissues. This was further confirmed by the development of choroid plexus carcinoma cell line (CCHE-45) which was characterized by the constitutive formation of aggresomes at MTOC. Aggresome formation implies presence of toxic protein over load and/or defective autophagy. The role of autophagic flux in the removal of aggresomes was further investigated. CCHE-45 cells displayed an increase in both basal and induced autophagic flux. Furthermore, microtubule-associated protein light chain 3 A- variant 1 (LC3A-V1) expression was silenced by promoter methylation in these cells. Restoring LC3A-V1 resulted in the elimination of the aggresomes and the recruitment of Lysosomal-Associated Membrane Protein (LAMP2) independent from autophagosome formation. Based on these findings we suggest that quality control autophagy in CCHE-45 is mediated by LC3A in aggresomes clearance. We propose that perturbation in the autophagic pathway by the absence of LC3A expression leads to a failure in aggresome degradation thus overcoming misfolded protein overload

Integration of 3D seismic attributes and production history in revaluation of gas potential - Abu Madi and El Qaraa fields.

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Optimization des réseaux de confédérations basés BGP

Rapport de stage de DEA.Le manuscrit est divisé en deux chapitres principaux. Dans le premier chapitre, nous commencerons par une brève présentation de l'architecture hiérarchique de l'Internet, du processus du routage, et du protocole BGP. Nous présenterons la problématique: le passage à l'échelle de IBGP et la difficulté de l'analyse de sa fiabilité, puis l'état de l'art sur l'optimisation des réflecteurs de routes et des confédérations. Dans une seconde partie nous présenterons nos contributions: un modèle basé sur la théorie des graphes pour représenter le réseau, une métrique pour évaluer la fiabilité d'une topologie de confédération, une solution informatique pour résoudre le problème de l'optimisation dans un temps linéaire et la validation expérimentale de son exactitude