Evaluating MAPSec by marking attack graphs

MAPSec has recently been introduced as a security protocol for mobile telecommunication networks in the midst of numerous threats and vulnerabilities. Our initial study reveals that MAPSec can only provide protection coverage to a minor portion of the total network vulnerabilities. Motivated by this discovery, we have devised a toolkit—Cellular Network Vulnerability Assessment Toolkit for Evaluation (eCAT) to identify: (1) Exact protection coverage of MAPSec, in terms of percentage of attacks prevented; (2) Other kinds of security protocols required in addition to MAPSec; and (3) The most vulnerable network areas. We use the results from eCAT in Coverage Measurement Formulas (CMF) to identify other vulnerabilities. Results from eCAT are dually useful in that they not only reveal MAPSec’s limited effectiveness but also provide insights into overall network vulnerabilities.     

Multi‐criteria algorithm‐based methodology used to select suitable domes for compressed air energy storage

Storing energy allows both the efficiency and availability of renewable energy to be increased, thus dissociating actual from expected generation and from consumption demands. Compressed air energy storage (hereinafter ‘CAES’) enables the efficient and cost‐effective storage of large amounts of energy, achieving a capacity of over 100 MWh. There are several geological structures that can be used as CAES, among which the use and construction of salt domes are particularly noteworthy. However, there is a high exploration risk associated with subsurface exploration. To this end, it is advisable to establish a detailed schedule to select and characterize structures, with the purpose of minimizing the aforementioned risk. Multi‐criteria algorithms can be used to establish a hierarchy of the alternatives and to identify the structures with the greatest potential with an objective approach. The analytic hierarchy process method is used in this paper as the selection algorithm, which is based on identifying and assessing criteria and weighting each criterion. In accordance with the analytic hierarchy process method, the goal was divided into a series of different level criteria, defining a breakdown structure of the problem to select salt domes. This paper defines a structure hierarchization method that allows the objective establishment of the areas with the highest potential for CAES, considering both technical and socioeconomic factors. Therefore, a supporting decision‐making method may be established to reduce the exploration risk associated with underground structures. Copyright © 2017 John Wiley & Sons, Ltd.     

The effects of surface elasticity and surface tension on the transverse overall elastic behavior of unidirectional nano-composites

The effects of surface elasticity and surface tension on the transverse overall behavior of unidirectional nano-scale fiber-reinforced composites are studied. The interfaces between the nano-fibers and the matrix are regarded as material surfaces described by the Gurtin and Murdoch model. The analysis is based on the equivalent inhomogeneity technique. In this technique, the effective elastic properties of the material are deduced from the analysis of a small cluster of fibers embedded into an infinite plane. All interactions between the inhomogeneities in the cluster are precisely accounted for. The results related to the effects of surface elasticity are compared with those provided by the modified generalized self-consistent method, which only indirectly accounts for the interactions between the inhomogeneities. New results related to the effects of surface tension are presented. Although the approach employed is applicable to all transversely isotropic composites, in this paper we consider only a hexagonal arrangement of circular cylindrical fibers.     

SUFFICIENT CONDITIONS FOR α-STABILITY OF LINEAR TIME-DELAY SYSTEMS

The asymptotic stability of time-delayed systems subject to multiple bounded point delays has received important attention in past years (see, for instance, Bourles, H. 1994. International Journal of Control , 59(2): 529-541; De la Sen, M. 2000. Electronics Letters , 36(4): 373-374; Xu, B. 2000. Journal of Mathematical Analysis and Applications , 282: 484-494). It is basically proved that the local f -stability in the delays (i.e., all the eigenvalues have prefixed strictly negative real parts located in Re s h - f < 0) may be tested for a set of admissible delays including possible zero delays either through a set of Lyapunov matrix inequalities or, equivalently, by checking that an identical number of matrices related to the delayed dynamics are all stability matrices. The result may be easily extended to check the k -asymptotic stability, independent of the delays; that is, for all the delays having any values, the eigenvalues are stable and located in Re s h k M 0 - (De la Sen, 2000; Xu, 2000). This number is 2 r for a set of r distinct point delays and includes all possible cases of alternate signs for summations for all the matrices of delayed dynamics (Xu, 2000).     

Computational study of thermal and mechanical properties of nylons and bio-based furan polyamides

We have investigated thermal and mechanical properties of bio-based furan polyamides and petroleum-based nylons with atomistic simulations. Glass transition temperatures estimated from a series of simulations at different temperatures were in good agreement with experimental measurements. Stress–strain relationships under uniaxial deformation conditions were also obtained and analyzed. Overall, polymers with smaller repeat units exhibited slightly higher glass transition temperatures and elastic moduli, which were attributed to higher cohesive energy densities. Furan polyamides displayed higher van der Waals cohesive energy densities and maintained more rigid planar structures near furan rings compared to nylons. As a result, bio-based furan polyamides showed higher glass transition temperatures and comparable mechanical properties despite having overall weaker hydrogen bonding than nylons.     

Personal multimedia services over a common home and access networking environment

This article presents a new end-to-end architecture model that will enable the deployment of a plethora of different multimedia services from diverse suppliers competitively coexisting over a common access and home networking environment. The model is focused on personal multimedia communication services and terminals. The proposed model is a segmentation of the end-to-end multimedia chain into several business segments. The interfaces among segments and functional entities inside each segment are identified and defined in the work. In order to study the impact level of the results achieved, a comparison with the approximation to NGN provided by current standardization bodies in the field (3GPP and TISPAN) is also included in the article. This comparison highlights the advantages of using this model as a solution to offer PMC services.     

Emission inventory: An urban public policy instrument and benchmark

Global concern with climate change has led to the development of a variety of solutions to monitor and reduce emissions on both local and global scales. Under the United Nations Framework Convention on Climate Change (UNFCCC), both developed and emerging countries have assumed responsibility for developing and updating national inventories of greenhouse gas emissions from anthropic sources. This creates opportunities and incentives for cities to carry out their own local inventories and, thereby, develop air quality management plans including both essential key players and stakeholders at the local level. The aim of this paper is to discuss the role of local inventories as an urban public policy instrument and how this type of local instrument may bring advantages countrywide in enhancing the global position of a country. Local inventories have been carried out in many cities of the world and the main advantage of this is that it allows an overview of emissions produced by different municipal activities, thereby, helps decision makers in the elaboration of efficient air quality management plans. In that way, measures aimed at the reduction of fossil fuel consumption to lower local atmospheric pollution levels can also, in some ways, reduce GHG emissions.     

Structural defects in (100) 3C-SiC heteroepitaxy: Influence of the buffer layer morphology on generation and propagation of stacking faults and microtwins

Growth of 3C-SiC on (100) Si has been performed via chemical vapor deposition under two pressure regimes (low and atmospheric pressure) in the early stage of growth. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) have been conducted to study the initial stage of growth while X-ray diffractometry (XRD) and TEM have been used to analyze thicker films and to detect and quantify defects, resulting in a comprehensive and detailed investigation of 3C-SiC structural defects. We have found out that the secondary nucleation of 3C-SiC island growth leads to a higher defect generation rate and, at the same time, to a more effective defect elimination rate. Hillocks found on the surface of thin samples grown under reduced pressure conditions are more pronounced as they seem to be a consequence of twins created in the early stage of growth. Finally, a different initial nucleation density (in the two pressure regimes considered) does not strongly influence stacking fault and microtwin density when growth of thick 3C-SiC films is performed. A very strong influence is indeed observed when 3C-SiC thickness is limited to hundreds of nanometers.     

Caffeine selectivity of divinylbenzene crosslinked polymers in aqueous media

The selective binding of caffeine to polymers is of interest in developing caffeine-specific sensors. The influence of the nature and quantity of crosslinking agents and functional monomers on the selectivity and binding affinity of a polymer to caffeine is reported. A high binding affinity and selectivity of divinylbenzene (DVB) crosslinked polymers toward caffeine was exhibited by the binding competition of caffeine with several dimethylated and chlorinated xanthines and N-methylated uric acids in aqueous media. To understand the nature of the caffeine–polymer interaction, we performed binding studies with solvents of different polarities and ionic strengths. The binding properties of DVB-based polymers containing different functional monomers were compared with Amberlite^® XAD resins. Analytes with hydrophilic and electron-withdrawing groups lowered their binding affinity with the polymer in comparison with caffeine and its dimethylated derivatives. The caffeine–polymer interaction appeared to be predominantly a hydrophobic π–π interaction but partly due to the presence of caffeine-specific sites. The reversibility of the caffeine–polymer binding was investigated, and the dissociation constants were approximated to be 27 and 6 mM. Dipole moments of caffeine and related molecules were estimated theoretically and were correlated with their corresponding B/T ratio, which is defined as the fraction of caffeine bound to the polymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 195–205, 2001