Trusted QoS Assurance Approach for Composite Service

The characteristics of service computing environment, such as service loose coupling, resource heterogeneity, and protocol independence, propose higher demand for the trustworthiness of service computing systems. Trust provisioning for composite services has become a hot research spot worldwide. In this paper, quality of service (QoS) planning techniques are introduced into service composition-oriented QoS provisioning architecture. By QoS planning, the overall QoS requirement of the composite service is decomposed into separate QoS requirement for every constituent atom service, the QoS level of which can subsequently be satisfied through well-designed service entity selection policies. For any single service entity, its QoS level is variable when the deployment environment or the load of service node changes. To mitigate the uncertainty, we put forward QoS preprocessing algorithms to estimate the future QoS levels of service entities with their history execution data. Then, based on the modeling of composite service and QoS planning, we design three algorithms, which include the time preference algorithm, cost/availability (C/A) preference algorithm, and Euclidean distance preference algorithm, to select suitable atomic services meeting the user’s requirements. Finally, by combining genetic algorithm and local-search algorithm, we propose memetic algorithm to meet the QoS requirements of composite service. The effectiveness of the proposed methods by which the QoS requirements can be satisfied up to 90% is verified through experiments.

Self-organization into ferroelectric and antiferroelectric crystals via the interplay between particle shape and dipolar interaction

Ferroelectricity and antiferroelectricity are widely seen in various types of condensed matter and are of technological significance not only due to their electrical switchability but also due to intriguing cross-coupling effects such as electro-mechanical and electro-caloric effects. The control of the two types of dipolar order has practically been made by changing the ionic radius of a constituent atom or externally applying strain for inorganic crystals and by changing the shape of a molecule for organic crystals. However, the basic physical principle behind such controllability involving crystal–lattice organization is still unknown. On the basis of a physical picture that a competition of dipolar order with another type of order is essential to understand this phenomenon, here we develop a simple model system composed of spheroid-like particles with a permanent dipole, which may capture an essence of this important structural transition in organic systems. In this model, we reveal that energetic frustration between the two types of anisotropic interactions, dipolar and steric interactions, is a key to control not only the phase transition but also the coupling between polarization and strain. Our finding provides a fundamental physical principle for self-organization to a crystal with desired dipolar order and realization of large electro-mechanical effects.

Theoretical Investigation of Energetic and its Effect on Cd-Hg Amalgam

<p>The observed anomaly in properties of mixing of Cd-Hg alloys in the molten state is successfully explained on the basis of the quasi-lattice model. The thermodynamic functions such as free energy of mixing, heat of mixing, entropy of mixing and chemical activity of the constituent atom of the alloys and microscopic functions like concentration-concentration fluctuation in long wavelength limit and Warren-Cowley short range order parameter of the alloys have been computed within the frame work of presented model. Most of the computed values are in good agreement with the experimental data. The pair-wise interaction energies between the species of the melt are found to depend considerably on temperature. Theoretical analysis suggests that hetero-coordination leading to the formation of complex Cd₂Hg is likely to exist but is of weakly interacting in nature.</p><p>Journal of Nepal Physical Society Vol.3(1) 2015: 60-66</p>

Hetero-Coordination in Liquid Pb-K Alloys

The observed asymmetry in properties of mixing of Pb-K alloys in the molten state is successfully explained on the basis of the quasi-lattice model. The thermodynamic functions such as free energy of mixing, enthalpy of mixing, entropy of mixing and chemical activity of the constituent atom of the alloys have been computed within the frame work of presented model. Most of the computed values are in good agreement with the experimental data. The pair-wise interaction energies between the species of the melt are found to depend considerably on temperature. Theoretical analysis suggests that hetero-coordination leading to the formation of complex Pb2K is likely to exist but is of weakly interacting in nature. The Himalayan Physics Vol. 5, No. 5, Nov. 2014 Page: 82-86

Lattice dynamics and intrinsic phonon broadening in the alloy Cu0.92Ge0.08

Using inelastic scattering of slow neutrons, we have determined the phonon frequencies and intrinsic line widths for the dilute face-centred cubic alloy Cu0.92Ge0.08 (Cu(Ge)) at 296 K. A limited number of measurements have also been made at 96 and 500 K. Spectrometer resolution calculations, using actual instrument and specimen parameters, have been performed and intrinsic phonon widths have been obtained by deconvolution from observed widths. The phonons in Cu(Ge) are well defined and similar to those for copper. Real contributions of the force-constant disorder in the alloy to intrinsic phonon widths are seen. To our knowledge, this is the first time that such effects have been conclusively observed for such dilute alloys. Constituent-atom mass differences are small for this alloy, and no mass disorder effects have been observed. Born–von Kármán model force-constant fits to the frequency data at 296 K are presented and compared with a model for pure copper. The frequency distribution and other thermal data, including the temperature dependence of the specific heat, the Debye–Waller factor, and the Debye temperature, are also given. The Cu(Ge) force constants are compared with those for 14 other iron-group transition elements and alloys. Systematic trends in the force constants as a function of 3d + 4s electron concentration are apparent.