Confined acoustic phonons in ultrathin SOI layers

We try to reproduce experimental mobility curves in ultrathin silicon-on-insulator inversion layers using a Monte Carlo simulator and a bulk model for the electron scattering with acoustic phonons. While it is possible to reproduce the experimental behavior for the thicker samples, the electron mobility is strongly overestimated when the thinnest samples are considered. The mobility curves for the thinnest samples can be reproduced using the same model if the deformation potential parameter increases as the silicon thickness decreases. This fact shows that acoustic phonons are also confined in ultrathin silicon on insulator layers. We then study confined phonons in single and three layer structures in order to give a physical motivation to the increase of acoustic phonon scattering rate for in ultrathin silicon layers.     

Second-Order Stiffness Matrix and Loading Vector of a Beam-Column with Semirigid Connections on an Elastic Foundation

The second-order stiffness matrix and corresponding loading vector of a prismatic beam–column subjected to a constant axial load and supported on a uniformly distributed elastic foundation (Winkler type) along its span with its ends connected to elastic supports are derived in a classical manner. The stiffness coefficients are expressed in terms of the ballast coefficient of the elastic foundation, applied axial load, support conditions, bending, and shear deformations. These individual parameters may be dropped when the appropriate effect is not considered; therefore, the proposed model captures all the different models of beams and beam–columns including those based on the theories of Bernoulli–Euler, Timoshenko, Rayleigh, and bending and shear.The expressions developed for the load vector are also general for any type or combinations of transverse loads including concentrated and partially nonuniform distributed loads. In addition, the transfer equations necessary to determine the transverse deflections, rotations, shear, and bending moments along the member are also developed and presented.     

A Comparative Study of the Use of Visual Communicative Signals in Interactions Between Dogs (Canis familiaris) and Humans and Cats (Felis catus) and Humans.

Dogs' (Canis familiaris) and cats' (Felis catus) interspecific communicative behavior toward humans was investigated. In Experiment 1, the ability of dogs and cats to use human pointing gestures in an object-choice task was compared using 4 types of pointing cues differing in distance between the signaled object and the end of the fingertip and in visibility duration of the given signal. Using these gestures, both dogs and cats were able to find the hidden food; there was no significant difference in their performance. In Experiment 2, the hidden food was made inaccessible to the subjects to determine whether they could indicate the place of the hidden food to a naive owner. Cats lacked some components of attention-getting behavior compared with dogs. The results suggest that individual familiarization with pointing gestures ensures high-level performance in the presence of such gestures; however, species-specific differences could cause differences in signaling toward the human. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Stress and Coping Model of Medication Adherence and Viral Load in HIV-Positive Men and Women on Highly Active Antiretroviral Therapy (HAART).

The authors tested a structural model that incorporated age, time since diagnosis, social support, coping, and negative mood as predictors of medication adherence and HIV viral load on 188 men and 134 women on highly active antiretroviral therapy (HAART). The authors used psychosocial latent factors formed from baseline measures to predict latent factors of adherence, as assessed by electronic monitoring and self-report, and viral load defined by indicators assessed over a 15-month period. Results from the model indicate that greater negative mood and lower social support are related to greater use of avoidance-oriented coping strategies. Use of these coping strategies by patients on HAART is related to poorer medication adherence and, subsequently, higher viral load. This model advances researchers' understanding of the contribution of psychosocial variables in predicting treatment adherence and disease progression in HIV-positive men and women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Types of Continuous Casters and the Quality of Continuous-Cast Slabs for Obtaining Rolled Products for Crucial Applications

This article examines the production of continuous-cast slabs for the production of thick (thicker than 20 mm) plates used in critical applications. It is shown that the melt needs to be carefully prepared for casting on a continuous caster. When the steel is made in a converter, the pig iron must be desulfurized beforehand and the steel tapped from the furnace must subsequently be treated on ladle-furnace and vacuum-degassing units. It was established that production of high-quality slabs suitable for obtaining critical rolled products can be consistently achieved only through the use of a vertical continuous caster. The bending and unbending which slabs undergo on curvilinear casters and the curved axis of such casters make it very difficult or even impossible to obtain slabs and thick plates that do not have asymmetrically distributed nonmetallic inclusions, axial segregation, and internal and external cracks. The article analyzes the success that the company Severstal' had in rebuilding its vertical slab caster. The project, carried out by TsNIIchermet and the companies ORMET-YuUMZ and Korad, shows that Russian metallurgical science, the metallurgical industry, and the machine-building sector have competitive engineering solutions to offer.     

Flux-line cutting in hard superconductors

The effect of flux-line cutting upon the magnetic behavior of hard superconductors subjected to a dc bias magnetic field H_z and a transverse field H_y undergoing half-wave oscillations of large amplitude is investigated theoretically. We have applied both the generalized double critical-state model and the elliptic flux-line-cutting one to interpret available experimental results for VTi ribbons. The predictions of these models are compared and discussed.     

Ultrasonic measurements of microelectronic resins

The elastic moduli, measured with the ultrasonic technique, of commercial silica filled epoxy resins used in the electronic circuits are reported. Measurements of velocity propagation and attenuation were carried out in large temperature and frequency ranges. Predictions of the theoretical models were compared with the experimental values. Explicit expressions of the elastic moduli were derived as functions of filler content and the properties of the matrix and the fillers. The influences of frequency and temperature on the elastic moduli and attenuation are discussed.     

Anomaly Detection Using Real-Valued Negative Selection

This paper describes a real-valued representation for the negative selection algorithm and its applications to anomaly detection. In many anomaly detection applications, only positive (normal) samples are available for training purpose. However, conventional classification algorithms need samples for all classes (e.g. normal and abnormal) during the training phase. This approach uses only normal samples to generate abnormal samples, which are used as input to a classification algorithm. This hybrid approach is compared against an anomaly detection technique that uses self-organizing maps to cluster the normal data sets (samples). Experiments are performed with different data sets and some results are reported.     

VPM: A visual,precise and multilevel metamodeling framework for describing mathematical domains and UML (The Mathematics of Metamodeling is Metamodeling Mathematics)

As UML 2.0 is evolving into a family of languages with individually specified semantics, there is an increasing need for automated and provenly correct model transformations that (i) assure the integration of local views (different diagrams) of the system into a consistent global view, and, (ii) provide a well-founded mapping from UML models to different semantic domains (Petri nets, Kripke automaton, process algebras, etc.) for formal analysis purposes as foreseen, for instance, in submissions for the OMG RFP for Schedulability, Performance and Time. However, such transformations into different semantic domains typically require the deep understanding of the underlying mathematics, which hinders the use of formal specification techniques in industrial applications. In the paper, we propose a multilevel metamodeling technique with precise static and dynamic semantics (based on a refinement calculus and graph transformation) where the structure and operational semantics of mathematical models can be defined in a UML notation without cumbersome mathematical formulae.     

Finding multiple solutions in job shop scheduling by niching genetic algorithms

The interest in multimodal optimization methods is increasing in the last years. The objective is to find multiple solutions that allow the expert to choose the solution that better adapts to the actual conditions. Niching methods extend genetic algorithms to domains that require the identification of multiple solutions. There are different niching genetic algorithms: sharing, clearing, crowding and sequential, etc. The aim of this study is to study the applicability and the behavior of several niching genetic algorithms in solving job shop scheduling problems, by establishing a criterion in the use of different methods according to the needs of the expert. We will experiment with different instances of this problem, analyzing the behavior of the algorithms from the efficacy and diversity points of view.