Adaptive Service Management in Mobile Cloud Computing by Means of Supervised and Reinforcement Learning

Since the concept of merging the capabilities of mobile devices and cloud computing is becoming increasingly popular, an important question is how to optimally schedule services/tasks between the device and the cloud. The main objective of this article is to investigate the possibilities for using machine learning on mobile devices in order to manage the execution of services within the framework of Mobile Cloud Computing. In this study, an agent-based architecture with learning possibilities is proposed to solve this problem. Two learning strategies are considered: supervised and reinforcement learning. The solution proposed leverages, among other things, knowledge about mobile device resources, network connection possibilities and device power consumption, as a result of which a decision is made with regard to the place where the task in question is to be executed. By employing machine learning techniques, the agent working on a mobile device gains experience in determining the optimal place for the execution of a given type of task. The research conducted allowed for the verification of the solution proposed in the domain of multimedia file conversion and demonstrated its usefulness in reducing the time required for task execution. Using the experience gathered as a result of subsequent series of tests, the agent became more efficient in assigning the task of multimedia file conversion to either the mobile device or cloud computing resources.     

Diffusion of hydrocarbons in the reforming catalyst: molecular modelling

This is an analysis of the diffusion and adsorption of the model reagents involved in the reforming process (heptane, methylcyclohexane and toluene) in the support (gamma-Al2O3) and catalyst (Pt/gamma-Al2O3) made use of in this process. Since the properties of these catalytic systems are influenced by the interactions between the atoms of the catalyst structure (host) and the atoms of the reagents (guest), analysis was carried out at the molecular level, using advanced computer simulations (molecular dynamics and forced diffusion) implemented in the MSI Software. The virtual host-guest model constructed with this software enabled a simulation of the real reforming system (reforming catalyst-reagents) and analysis of the diffusion phenomenon in this system.The results show that the propensity of the reagents to adsorption and the host-guest interaction energy are correlated with the coefficients of diffusion. The diffusion coefficient values are lower in the catalyst than in the support, probably because of the increased adsorption at the active Pt centres. The decrease in pore diameter from 17 to 10A brings about a decrease in the diffusion coefficients not only due to steric hindrance, but also as a result of capillary condensation. The favourable influence of temperature is more distinct in models characterised by a larger pore size. This is so because molecular diffusion dominates over the mechanism of Knudsen diffusion, which increases the temperature-dependence of diffusion.     

Plasma Concentration of Cortisol Negatively Associates with Platelet Reactivity in Older Subjects

The interaction of platelets with steroid hormones is poorly investigated. Age is one of the factors that increase the risk of pathological platelet reactivity and thrombosis. The aim of this study was to assess whether there were associations between platelet reactivity and plasma cortisol levels in volunteers aged 60–65 years. For this purpose, impedance aggregometry in whole blood measured after arachidonic acid, collagen, or ADP stimulation was used to estimate platelet reactivity and mass spectrometry was used to measure peripheral plasma cortisol concentration. Statistically significant negative correlations were observed between cortisol concentration and platelet reactivity in response to arachidonic acid and ADP, but not to collagen. The presented results suggest for the very first time that cortisol is a new endogenous modulator of platelet reactivity in the elderly population.     

Effect of impact angle and projectile size on sputtering efficiency of solid benzene investigated by molecular dynamics simulations

Molecular dynamics computer simulations have been used to investigate the effect of the cluster size on the sputtering yield dependence on the impact angle. Ar₃₆₆ and Ar₂₉₅₃ cluster projectiles with 14.75 keV of incident energy are directed at the surface of a solid benzene crystal described by a coarse-grained representation at angles between 0° and 70°. It is observed that the shape of the angular dependence of sputtering efficiency is strongly affected by the cluster size. For the Ar₃₆₆ cluster, the sputtering yield only slightly increases with the impact angle, has a broad maximum around 40°, and decreases at larger angles. For the Ar₂₉₅₃ cluster, the yield strongly increases with the impact angle, has a maximum around 45° followed by a steep decrease at larger angles. For both investigated cluster projectiles the primary energy is deposited so close to the surface so that the sputtering efficiency only weekly benefits from the shift of the deposited energy profile toward the surface which occurs at larger impact angles. In this study, molecular dynamics computer simulations are used to probe the effect of the impact angle on the efficiency of ejection molecules emitted from solid benzene by 14.75 keV Ar₃₆₆ and Ar₂₉₅₃ clusters.     

Curvopeptin: A New Lanthionine‐Containing Class III Lantibiotic and its Co‐substrate Promiscuous Synthetase

Lantibiotics are ribosomally synthesized peptides containing post‐translationally installed lanthionine thioether bridges. Recently characterized class III lantibiotics have also revealed the occurrence of labionin, a novel carbacyclic variation of lanthionine, and highlighted the structural diversity within this group. Here we describe the discovery and characterization of curvopeptins produced by Thermomonospora curvata, the first class III lantibiotics of thermophilic origin. Furthermore, investigation of the modifying enzyme CurKC and in particular the characterization of its specificity toward phosphorylation co‐substrates was performed. Remarkably, all investigated NTPs and dNTPs were accepted by the enzyme, although the purine nucleotides ATP/dATP and GTP/dGTP were the preferred co‐substrates. This finding complements previous studies on the class III lantibiotic synthetases LabKC and EryKC and underlines the surprising promiscuity of the Ser/Thr‐kinase domain. Enzymatic studies with a precursor peptide mutant allowed the assignment of all dehydration sites and further GC‐MS analysis revealed the presence of lanthionine as the main type of intramolecular ring.     

3-D modelling of rectangular circuits as the particular class of spatially interconnected systems on the plane

Multidimensional Systems and Signal Processing - This paper is devoted to modelling the spatially interconnected system, particularly the regular circuit displayed in the plane as a 3-D system with...     

2D Phononic Crystals: Progress and Prospects in Hypersound and Thermal Transport Engineering

The central concept in phononics is the tuning of the phonon dispersion relation, or phonon engineering, which provides a means of controlling related properties such as group velocity or phonon interactions and, therefore, phonon propagation, in a wide range of frequencies depending on the geometries and sizes of the materials. Phononics exploits the present state of the art in nanofabrication to tailor dispersion relations in the range of GHz for the control of elastic waves/phonons propagation with applications toward new information technology concepts with phonons as state variable. Moreover, phonons provide an adaptable approach for supporting a coherent coupling between different state variables, and the development of nanoscale optomechanical systems during the last decade attests this prospect. The most extended approach to manipulate the phonon dispersion relation is introducing an artificial periodic modulation of the elastic properties, which is referred to as phononic crystal (PnC). Herein, the focus is on the recent experimental achievements in the fabrication and application of 2D PnCs enabling the modification of the dispersion relation of surface and membrane modes, and presenting phononic bandgaps, waveguiding, and confinement in the hypersonic regime. Furthermore, these artificial materials offer the potential of modifying and controlling the heat flow to enable new schemes in thermal management.     

Composite SBA-15/MFI Type Materials: Preparation, Characterization and Catalytic Performance

SBA-15 type mesoporous molecular sieve was prepared and used as a parent material for synthesis of a SBA-15/zeolite composite. Thus, after addition of an aluminum source into the pristine sample, it was subjected to recrystallization in the water-vapor phase to give the SBA-15/MFI composites. The samples obtained were characterized by XRD, nitrogen sorption, scanning and transmission electron microscopies, ²⁷Al MAS NMR and FT IR. The materials after recrystallization retained their mesoporous character. Characteristics of the material revealed that all the aluminum added was inserted into the final hybrid. As shown by FT IR and NMR, at least some of aluminum was introduced into the nanoparticles of MFI and adopted four-fold coordination, typical for zeolites. Formation of Brønsted acid centres was directly confirmed by IR studies. The catalytic activity was screened in the liquid-phase isomerization of α-pinene. The main products of α-pinene transformations were camphene, limonene and γ-terpinene. The overall selectivity toward camphene + limonene was ca. 90%. Taking into account the low amount of the MFI phase present in a composite sample, calculated initial reaction rate was comparable with other catalytic systems explored in the isomerization of α-pinene.     

The influence of the initial acidity of HFER on the status of Co species and catalytic performance of CoFER and InCoFER in CH4-SCR-NO

The role of the initial acidity of ferrierite type zeolite on the status of cobalt and the catalytic activity of CoFER and InCoFER was investigated. Two FER zeolites were used: NH₄FER without any pretreatment (FER-1) and the same zeolite, dehydroxylated at 825 K (FER-2). Dehydroxylation removed most of the Si–OH–Al groups, therefore the resulting zeolite revealed practically no ion exchange capacity. The status of cobalt was followed by IR spectroscopy with probe molecules: CO (a probe for Co²⁺) and NO (a probe for Co³⁺). The introduction of cobalt by solid-state ion exchange produced divalent cobalt in exchange positions and in the form of oxide-like clusters, their respective concentration was determined by quantitative IR experiments of CO sorption. The amount of Co³⁺, present in CoFER-1 and InCoFER-1, was also determined. All these forms of cobalt were practically absent from CoFER-2 and InCoFER-2. The NO conversion and selectivity to N₂ of CoFER-2 in CH₄-SCR-NO was poor, indicating the essential role of the initial acidity of the ferrierite matrix on the formation of catalytically active Co species. The introduction of indium into CoFER only slightly increased the NO conversion and shifted the reaction path from NO₂ towards N₂ formation for FER-1, while greatly improved the catalytic performance of the FER-2 series.