Confidentiality considerations: multimedia signals transmission over different wireless channels utilized efficient secured model

The confidentiality of highly-sensitive multimedia signals is considered in this paper, it can be enhanced by efficient secured model utilizing several-layer security algorithms. The hybrid data hiding and cryptographic techniques are merged for constructing secured model. The Least Significant Bit (LSB) data hiding steganography is utilized with a 2-D Logistic-based map (Model-I) and second Model-II involves data hiding merging within chaotic-Baker-based image encryption security techniques. ?Performance analyzing and comparison have been presented utilizing various images for examining the applicability of the different proposed image security scenarios for securing wireless image transmission over noise-free, and noisy channels. Moreover, the proposed algorithms are applied for transmission over Orthogonal Frequency-Division Multiplexing (OFDM) channels, and their performance is evaluated under different conditions of fading environments with utilizing the powerful error control schemes in the case of SUI-3 model channel and randomizing the packet based on the encryption tools. An equalizer is used to mitigate the impact of composite fading. A multi-layer security model using Discrete Wavelet Transform (DWT) steganography with chaotic Baker encryption is proposed to protect highly-sensitive text based data records. The results reveal that it can be used efficiently for protecting highly-sensitive text message and records (text-based data). The timing analysis and comparative study are considered with respect to the previous related works.

     

Cascade high-gain observers for a class of nonlinear systems with large delayed measurements

This paper proposes a cascade high-gain observer for a class of triangular nonlinear systems with large and diverse time delays at states and output equation. Compared with some existing results in the literature, the main contribution is to consider the simultaneous and diverse delays in both states and output and further, to propose a cascade observer in dealing with arbitrarily large delayed measurements. By choosing a suitable Lyapunov-Krasovskii functional, the sufficient condition is presented that guarantees the exponential convergence of observation error to the origin. Simulation results on a numerical example and a practical case study involving inverted pendulum are finally given to illustrate the effectiveness of the proposed approach.     

MapReduce scheduling algorithms: a review

Recent trends in big data have shown that the amount of data continues to increase at an exponential rate. This trend has inspired many researchers over the past few years to explore new research direction of studies related to multiple areas of big data. The widespread popularity of big data processing platforms using MapReduce framework is the growing demand to further optimize their performance for various purposes. In particular, enhancing resources and jobs scheduling are becoming critical since they fundamentally determine whether the applications can achieve the performance goals in different use cases. Scheduling plays an important role in big data, mainly in reducing the execution time and cost of processing. This paper aims to survey the research undertaken in the field of scheduling in big data platforms. Moreover, this paper analyzed scheduling in MapReduce on two aspects: taxonomy and performance evaluation. The research progress in MapReduce scheduling algorithms is also discussed. The limitations of existing MapReduce scheduling algorithms and exploit future research opportunities are pointed out in the paper for easy identification by researchers. Our study can serve as the benchmark to expert researchers for proposing a novel MapReduce scheduling algorithm. However, for novice researchers, the study can be used as a starting point.

     

Imbalance factor: a simple new scale for measuring inter-class imbalance extent in classification problems

Knowledge and Information Systems - Learning from datasets that suffer from differences in absolute frequency of classes is one of the most challenging tasks in the machine learning field. Efforts...     

Stair Climber Smart Mobile Robot (MSRox)

Most current mobile robots are designed to determine their actions according to their positions. Before making a decision, they need to localize themselves. Thus, their observation strategies are mainly for self-localization. However, observation strategies should not only be for self-localization but also for decision making. We propose an observation strategy that enables a mobile robot to make a decision. It enables a robot equipped with a limited viewing angle camera to make decisions without self-localization. A robot can make a decision based on a decision tree and on prediction trees of observations constructed from its experiences. The trees are constructed based on an information criterion for the action decision, not for self-localization or state estimation. The experimental results with a four legged robot are shown and discussed.     

A high performance optimal dynamic routing algorithm with unicast multichannel QoS guarantee in communication systems

Dynamic routing protocols play an important role in today??s networks. In communication networks, in a current data transmission session, failing nodes and links is a destructor event which loses packets immediately and it can also waste network resources and services seriously. Sometimes failing nodes can disconnect data transmission and, therefore, lost packets must be retransmitted by new session. In this situation, the routing algorithm must discard failed nodes and must repair paths of session by rerouting them. In this case, static routing algorithms and some existing dynamic routing algorithms cannot manage faulty paths fairly and network efficiency is seriously declined. The capability to compensate for topology changes is the most important advantage dynamic routing offers over static routing. An efficient dynamic routing algorithm tries to reroute and change faulty paths without disconnecting sessions and keeps packet transmission in a desirable rate. It is important to tell that a dynamic routing algorithm should provide multi essential parameters, such as acceptable delay, jitter, bandwidth, multichannel paths, virtual channel connections, label switching technology, optimal resource allocation, optimal efficiency in the case of multimedia, and real time applications. This paper proposes a new dynamic framework which transforms static routing algorithms to dynamic routing algorithms. Using the new dynamic framework, this paper constructs an Optimal Dynamic Unicast Multichannel QoS Routing (ODUMR) algorithm based on the Constrained Based Routing (CBR) and Label Switching Technology which is called as ODUMR Algorithm. The performance of ODUMR is analyzed by network simulator tools such as OpNet, MATLAB, and WinQSB. ODUMR produces results better than the existing static and dynamic routing algorithms in terms of necessary parameters.     

A Comprehensive Study of Diffusion Bonding of Mg AZ31 to Al 5754, Al 6061 and Al 7039 Alloys

In the present study, microstructural and mechanical properties of diffusion bonding of AZ31–Mg with Al 5754, Al 6061, and Al 7039 alloys were compared under same conditions. The vacuum diffusion processes were performed at a temperature of 440 °C, the pressure of 29 MPa, and a vacuum of 1?×?10^?4 torr for 60 min. The microstructural characterizations were investigated using optical microscopy and scanning electron microscopy equipped with EDS analysis and linear scanner. The XRD analysis was performed to study phase figures near the interface zone. The results revealed the formation of brittle intermetallic compounds like Al₁₂Mg₁₇, Al₃Mg₂, and their other combinations at bonding interfaces of all samples. Additionally, the hardness of Al alloys seemed to play a key role in increasing diffusion rate of magnesium atoms toward the aluminum atoms, with Al 6061 alloy having the highest diffusion rate. It consequently led to an increase in diffusion rate and thus formation of a strong diffusion bonding between magnesium and aluminum alloys. The highest strength was about 42 MPa for the diffusion bonding between Mg AZ31 and Al 6061. Further investigations on surfaces indicated that the brittle phases especially Al₃Mg₂ caused brittle fracturing.     

A Study on Elliptical Cross-Sectioned Spiral Equal-Channel Extrusion of AA7075: FE Simulation and RSM Approach

Elliptical cross-sectioned spiral equal-channel extrusion is newly developed sever plastic deformation technique that can be used for processing of cylindrical components. In the present study, numerical and experimental investigations were made to identify optimal setting of process parameters i.e. torsion angle, elliptical rotation transitional length and elliptical length ratio attaining minimum punch force and maximum effective strain. Firstly, the process was numerically simulated by using DEFORM software. Then, 15 series of simulation runs was implemented based on central composite design incorporating three-factors and three-levels. Response surface methodology was used here to correlate relationship between factors and responses. In order to find optimum solution regarding maximum strain and minimum punch force, desirability approach was used. The optimization results showed that for achieving maximum strain (that is most desirable during severe plastic deformation), settings of 120° torsion angle, 9 mm channel length and 1.45 elliptical length ratio was required. From the results obtained through experiments, it was found that performing three-passes ECSEE under optimal combination of factors resulted in about 30% enhancement in values of ultimate tensile strength and hardness.     

The GA Optimization Performance in the Microstructure and Mechanical Properties of MMNCs

This paper is aimed at development of an effective approach based on the combination of GA, FEM and artificial intelligent methods to determine the optimum conditions of Al Matrix nano composites in terms of microstructure and mechanical properties. Using the stir casting method, alumina nano-particles were incorporated into the Al–Si aluminum alloy. Characterization of the mechanical properties showed that the presence of nano particles significantly improved the hardness and strength of the composites. Then artificial neural network and finite element technique were implemented in order to predict the mechanical properties and genetic algorithms were used for the process conditions optimization. It was revealed that the proposed model is a useful and efficient method to find the optimal process conditions in stir casting.     

Prestress losses in fibreglass pretensioned concrete compression members

Fibreglass has been used recently as a prestressing material in concrete structures, and it has demonstrated some advantages over steel tendons especially in corrosive environments. An experimental estimation of the long term losses of concrete columns and piles pretensioned with fibreglass (S-2 glass) is presented in this paper. Three identical sets of steel and fibreglass specimens with nominal dimensions of 152 mm×102 mm×2.6 m (6 in ×4 in ×102 in) were instrumented and tested to evaluate prestress losses under axial compression loads at different stress levels. Results after 20 months show that prestress losses in fibreglass tendons are less than those in steel tendons. The effective prestress for fibreglass pretensioned specimens can be predicted accurately using the step-by-step method. The measured data were compared with several models. For a practical applied stress of 0.3f_c ^′, the current ACI and Bazant equations for creep and shrinkage predicted the strain history, prestress losses, and effective prestress of fibreglass pretensioned concrete specimens with good accuracy.

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Resume La fibre de verre a été récemment utilisée comme matériau de précontrainee dans les structures en béton et présente certains avantages sur les armatures d'acier, surtout dans les environnements corrosifs. C'est la dégradation des structures en béton préconstraint et en béton armé dans ce type d'environment qui a conduit à rechercher d'autres matériaux de précontrainte plus durables. C'est ainsi que la fibre de verre est apparue comme une solution de remplacement. Elle a pour propriétés une haute résistance à la traction, une bonne adhérence et une excellente résistance à la corrosion. Le présent rapport donne une estimation expérimentale des pertes à long terme des poteaux et des pieux précontraints par prétension avec de la fibre de verre. Trois séries identiques d'éléments d'acier et de fibre de verre avec des dimensions nominales de 152 mm × 102 mm × 2,6 m ont été essayées pour évaluer les pertes de précontrainte sous des charges de compression axiale à différents niveaux de contrainte. Les résultats après 20 mois ont indiqué qu'avec les armatures d'acier les pertes sont plus importantes qu'avec des armatures de fibre de verre. L'efficacité de la précontrainte des éléments avec fibres de verre peut être déterminée avec exactitude. Les données mesurées sont comparées avec plusieurs modèles de fluage et de retrait. Pour une contrainte de 0,3 f_c ^' exercée, les équations actuelles de l'ACI et Bažant pour le fluage et le retrait ont permis de prévoir avec une assez grande précision le processus de déformation, les pertes de précontrainte et l'efficacité de la précontrainte des éléments de béton à fibres de verre.