New Bandwidth Upgradation and Degradation Algorithms for Next Generation of Wireless Network Systems

Wireless Personal Communications - With the increase of the usage of multimedia applications, the next generation of wireless networks need to satisfy the quality of the transmitted application...     

Deployment and validation of out of band IP traceback approach (OBTA) in wireless mesh network

Wireless mesh networks (WMNs) have acquired recently enormous attention and momentum; therefore, security aspects have been a fundamental concern for them. Among catastrophic threats on WMNs, Denial‐of‐Service attacks that have become a severe danger because of their plug‐and‐play structural design. Unfortunately, preventing a Denial‐of‐Service attack presents a challenging issue. This fact is induced with the appearance of the source IP addresses spoofing. The resolution key of this issue is to reveal the attack source based on the path through which the attack packet passes. For this, many researchers in IP traceability field propose various methods and techniques to deal with the issue. In this article, we conceive a novel approach named out of band IP traceback approach in WMN (IEEE 802.11s). We create a new architecture using signaling messages for discovering the real source(s) of IP packets. Our solution is based on a security‐oriented signaling protocol. This protocol allows specialized signaling entities to communicate via reliable signaling information. This fact permits us to perform a simple and efficient traceback. In our novel approach, we use 2 radios: the first one transmits normal data packets whereas the second is reserved to exchange IP traceback information. The performance of the proposed scheme is analyzed via simulation analysis using the Network Simulator 3. The simulation results show that our scheme is efficient in dealing with the traceback problem in WMN environments.     

Kinetics of leaching of tunisian phosphate ore particles in dilute phosphoric acid solutions

Van der Sluis et al.'s model was used to determine the rate of the partial dissolution of a Tunisian phosphate rock with dilute phosphoric acid (1.5 mass% P₂O₅). When the temperature rises from 25 to 90°C, for a given particle size, the mass-transfer coefficients, k_L°, vary from 3 × 10^?3 to 8 × 10^?3 m ·s^?1. The corresponding diffusion coefficients, D, lies between 6 × 10^?7 and 27 × 10^?7 m²·s^?1. Activation energy is equal to 14 kJ·mol^?1 and values of k_L°, at 25°C, are in the range of 0.28 × 10^?3 and 4 × 10^?3 m·s^?1 when the agitation speed goes from 220 to 1030 rpm, showing that the leaching process is controlled by diffusion rather than by chemical reaction.     

Palladium Nanoparticles in Glycerol: A Versatile Catalytic System for C?X Bond Formation and Hydrogenation Processes

Palladium nanoparticles stabilised by tris(3‐sulfophenyl)phosphine trisodium salt in neat glycerol have been synthesised and fully characterised, starting from both Pd(II) and Pd(0) species. The versatility of this innovative catalytic colloidal solution has been proved by its efficient application in C X bond formation processes (X=C, N, P, S) and C C multiple bond hydrogenation reactions. The catalytic glycerol phase could be recycled more than ten times, preserving its activity and selectivity. The scope of each of these processes has demonstrated the power of the as‐prepared catalyst, isolating the corresponding expected products in yields higher than 90%. The dual catalytic behaviour of this glycerol phase, associated to the metallic nanocatalysts used in wet medium (molecular‐ and surface‐like behaviour), has allowed attractive applications in one‐pot multi‐step transformations catalysed by palladium, such as C C coupling followed by hydrogenation, without isolation of intermediates using only one catalytic precursor.

     

Color and fastness study of wool dyeing in multiple reuse dye baths using acid and reactive dyestuffs in laboratory scale

The possibility to reuse residual dye baths for wool dyeing with acid and reactive dyestuffs (Blue Marine Irganol 2RLS and Blue Lanasyn BLS, respectively) was investigated in this study. The residual dye baths were reconstituted and reused 20 consecutive times for dye concentration of 1%. A series of colorimetric measurements were carried out for the obtained samples in order to evaluate the conformity and the uniformity of their color as well as their dyeing fastness. In particular, we were interested in wash, rubbing, and light fastness. The obtained results for these three criteria of evaluation were very satisfactory: (1) color conformity (expressed in Colour Measurement Committee (2:1) and CIEDE2000 color differences) lower than the textile threshold of 1, (2) good evenness, and (3) color fastness not deteriorated in spite of the multiple reuses of dye baths. In this paper, the feasibility and efficiency of this technique was proved to considerably reduce water, dyes, and auxiliary quantities without disturbing the quality of the dyeing behavior.     

Spatially selective laser irradiation method controlled by real-time image analysis: optical aspects

We present a spatially selective irradiation method for laser treatment of biological surfaces. The purpose is to irradiate only the pathological targets and to preserve the healthy surrounding parts. We are interested here in the optical arrangement of the device and in the evaluation of its physical limitations before it is used for medical purposes. The method uses real-time image analysis applied to the video imagery of the surface to be treated. The result of the image analysis generates the control signal to a spatial light modulator, allowing us to project an adequate repartition of laser irradiance on the surface to be treated. Experimental results demonstrate a spatial selectivity of approximately 10 microm for a 6.7 mm x 5 mm field. The optical system has no moving parts (unlike galvanometric scanners) and is able to irradiate multiple targets simultaneously with different doses.     

A decision support system assessing the trust level in supply chains based on information sharing dimensions

Assessing customer trust in suppliers with regards to its influencing factors is an important open issue in supply chain management literature. In this paper, a customer trust index is designed as the trust level arising from the information sharing degree and quality, related to the information shared by a supplier with his customer. The customer trust level is evaluated using a fuzzy decision support system integrating information sharing dimensions. The core is a rule-based system designed using the results of questionnaires and interviews with supply chain experts. Several tests were generated in order to analyze the impact of the different information sharing attributes on the customer trust index. The developed approach is then applied to a real supply chain from the textile industry. Results show large differences of weight and impact between the different information-related factors that build the customer trust index. It is also shown that the proposed system has an important role in ensuring the objectivity of the trust assessment process and in helping decision makers evaluate their business partners.     

A secure fog-based platform for SCADA-based IoT critical infrastructure

The rapid proliferation of Internet of things (IoT) devices, such as smart meters and water valves, into industrial critical infrastructures and control systems has put stringent performance and scalability requirements on modern Supervisory Control and Data Acquisition (SCADA) systems. While cloud computing has enabled modern SCADA systems to cope with the increasing amount of data generated by sensors, actuators, and control devices, there has been a growing interest recently to deploy edge data centers in fog architectures to secure low-latency and enhanced security for mission-critical data. However, fog security and privacy for SCADA-based IoT critical infrastructures remains an under-researched area. To address this challenge, this contribution proposes a novel security “toolbox” to reinforce the integrity, security, and privacy of SCADA-based IoT critical infrastructure at the fog layer. The toolbox incorporates a key feature: a cryptographic-based access approach to the cloud services using identity-based cryptography and signature schemes at the fog layer. We present the implementation details of a prototype for our proposed secure fog-based platform and provide performance evaluation results to demonstrate the appropriateness of the proposed platform in a real-world scenario. These results can pave the way toward the development of a more secure and trusted SCADA-based IoT critical infrastructure, which is essential to counter cyber threats against next-generation critical infrastructure and industrial control systems. The results from the experiments demonstrate a superior performance of the secure fog-based platform, which is around 2.8 seconds when adding five virtual machines (VMs), 3.2 seconds when adding 10 VMs, and 112 seconds when adding 1000 VMs, compared to the multilevel user access control platform.     

Analysis of two-dimensional transient conduction–radiation problems in an anisotropically scattering participating enclosure using the lattice Boltzmann method and the control volume finite element method

This study deals with the performance evaluation of the lattice Boltzmann method (LBM) and the control volume finite element method (CVFEM) in terms of their abilities to provide accurate results in solving combined transient conduction and radiation mode problems in a two-dimensional rectangular enclosure containing an absorbing, emitting and anisotropically scattering medium. Coupling problems for mixed kind thermal boundary are worked out for reflective interfaces. Effects of various parameters are studied on the distributions of temperature, radiative and conductive heat fluxes. The results of the LBM in conjunction with the CVFEM have been found to compare very well with available results in the literature. So, the numerical approach is extended to deal with a practical combination of mixed boundary conditions in a transient multi-dimensional combined conductive radiative heat transfer problems in an emitting, absorbing, anisotropically scattering enclosure.