Top-gating of p-Si/SiGe/Si inverted modulation-doped structures

Low-temperature electrical properties of two-dimensional hole gases (2-DHGs) in Si/Si0.8Ge0.2/Si inverted modulation-doped structures have been investigated at different hole densities using a metal semiconductor gate sputtered on top of these structures. The 2-DHG which is supplied to the inverted interface of Si/SiGe/Si quantum well by a Si boron-doped layer spatially grown beneath the alloy, was controlled in the range of 1.5–7.8×1011 cm–2 hole density by biasing the top gate. With increasing 2-DHG sheet density, the hole wave function of these structures expands and moves away from inverted interface, consequently the mobility enhances. These results may be understood theoretically by elaborating the role of interface charge, roughness, and alloy scattering mechanisms in limiting the mobility of holes at the inverted interface

Presentation of Self on Facebook

In recent years, Facebook has erupted as a phenomenon in a variety of contexts. It is quickly becoming a significant topic in academia, where there is a varied and quickly growing body of literature in a number of fields. Facebook has been rapidly adopted by users who use it to maintain existing relationships and also as a medium in which to present themselves through their profiles information. This research aims to explore how much users present themselves on Facebook and the impressions they want others to form of them when looking at their profiles. To examine the types of self-presentation displayed in Facebook profiles, this study uses the self-presentation theory (Goffman, 1959). The questionnaire survey was employed as the instrument for data collection in this study. The results revealed that the level of self-presentational behaviors to be moderate and the level of expected impressions from Facebook friends for most of the respondents was not high. Additionally, the findings indicated that there was a significant difference for expected impressions from Facebook friends among different races. The study also showed that the extent of information Facebook users self-disclose was moderate. It can be concluded that respondents have moderately self-presented through Facebook by changing their profile pictures, leaving comments, writing on their ontacts' "walls", as well as "lik(ing)" their contacts' posts. In addition, in spite of respondents' “low” level of expectancy, they were active in publishing their 'selves' in forms of pictures as well as sharing special links/videos/ texts. Furthermore, based on this study, self-presentation in form of information exaggeration is not independent of race

Improved AODV route recovery in mobile ad-hoc networks using a genetic algorithm

An important issue in ad-hoc on-demand distance vector (AODV) routing protocols is route failure caused by node mobility in the MANETs. The AODV requires a new route discovery procedure whenever a route breaks and these frequent route discoveries increase transmission delays and routing overhead. The present study proposes a new method for AODVs using a genetic algorithm to improve the route recovery mechanism. When failure occurs in a route, the proposed method (GAAODV) makes decisions regarding the QOS parameter to select source or local repair. The task of the genetic algorithm is to find an appropriate combination of weights to optimize end-to-end delay. This paper evaluates the metrics of routing overhead, average end-to-end delay, and packet delivery ratio. Comparison of the new algorithm and AODV (RFC 3561) using a NS-2 simulator shows that GAAODV obtains better results for the QOS parameters

Linear Parameter-Varying Embedding of Nonlinear Models with Reduced Conservativeness

In this paper, a systematic approach is developed to embed the dynamical description of a nonlinear system into a linear parameter-varying (LPV) system representation. Initially, the nonlinear functions in the model representation are approximated using multivariate polynomial regression. Taking into account the residuals of the approximation as the potential scheduling parameters, a principle component analysis (PCA) is conducted to introduce a limited set of auxiliary scheduling parameters in coping with the trade-o? between model accuracy and complexity. In this way, LPV embedding of the nonlinear systems and scheduling variable selection are jointly performed such that a good trade-o? between complexity and conservativeness can be found. The developed LPV model depends polynomially on some of the state variables and affinely on the introduced auxiliary scheduling variables, which all together comprise the overall scheduling vector. The methodology is applied to a two-degree of freedom (2-DOf) robotic manipulator in addition to an academic example to reveal the effectiveness of the proposed method and to show the merits of the presented approach compared with some available results in the literature.Comment: 7 pages, 2 figures, IFAC World Congress, Berlin, 202