Algorithm selection and instance space analysis for curriculum-based course timetabling

Journal of Scheduling - We propose an algorithm selection approach and an instance space analysis for the well-known curriculum-based course timetabling problem (CB-CTT), which is an important...     

The effect of nicotine and attention allocation on physiological and self-report measures of induced anxiety in PTSD: A double-blind placebo-controlled trial.

Rates of smoking among populations with psychiatric disorders are more than twice as high as among the general population, yet there are few controlled studies of the mechanisms of this relationship. This trial examined the effect of nicotine by way of cigarette smoking on both self-report and autonomic parameters of anxiety among individuals with PTSD who were also heavy smokers. Half of the participants were randomized to an anxiety-eliciting condition, whereas the other half were assigned to a condition of neutral emotional content. Within each of these conditions, participants were randomized into a nicotine condition (high-yield nicotine cigarette) or a placebo condition (denicotinized cigarette). The final layer of randomization involved assigning participants to either an attention-demanding task or a no task condition. We examined the interactive effects of nicotine and attentional demand on parameters of anxious responding. Nicotine exerted an anxiolytic effect relative to placebo on self-report measures; however, nicotine did not interact with attentional demand in producing this effect. In contrast to the findings on the self-report measures of distress, nicotine enhanced autonomic reactivity to trauma cues, thereby suggesting a decoupling of self-reported anxiety and autonomic arousal associated with responding to trauma-relevant cues. The implications for understanding smoking and psychiatric comorbidity are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Complexity, class dynamics, and distance learning

Classroom participants learn early on that each classroom has its own dynamic comprised of personalities, motivation levels, skills, and other variables. This paper explores features of complexity theory—nonlinearity and emergent self-organization—relevant to dynamics in physical or virtual classrooms. These central notions of complexity theory and their importance in composition classrooms help explain why students in virtual classrooms are often less successful than their physical classroom counterparts in negotiating the eddies of virtual interactions. The paper closes with a brief consideration of how teachers can interrogate all the elements of teaching and classroom context (whether physical or virtual) to influence the emergent dynamic of our classrooms.     

Two Enhanced Fourth Order Diffusion Models for Image Denoising

This paper presents two new higher order diffusion models for removing noise from images. The models employ fractional derivatives and are modifications of an existing fourth order partial differential equation (PDE) model which was developed by You and Kaveh as a generalization of the well-known second order Perona-Malik equation. The modifications serve to cure the ill-posedness of the You-Kaveh model without sacrificing performance. Also proposed in this paper is a simple smoothing technique which can be used in numerical experiments to improve denoising and reduce processing time. Numerical experiments are shown for comparison.     

Instance space analysis for a personnel scheduling problem

Annals of Mathematics and Artificial Intelligence - This paper considers the Rotating Workforce Scheduling Problem, and shows how the strengths and weaknesses of various solution methods can be...     

Fully superconducting rectifiers and fluxpumps Part 1: Realized methods for pumping flux

The magnetic and electrical properties of superconductors were a challenge for many inventors and designers to use superconducting materials in the construction of fully superconducting voltage and current sources commonly called fluxpumps. In the past twenty years a large variety of mechanically or electrically driven devices have been proposed and successfully operated.In this review the basic principle of operation of each class of devices is shown and specific material problems and limitations are reported. The review will be published in two parts.Part 1 deals with mechanical devices such as flux compressors and dynamos. Although those devices must have been of great importance for technical application, their construction and operation offered great experience with regard to the properties of superconducting materials, their joint techniques switching and mechanical and magnetic stability under ac and dc conditions.In this part also a start is made with the more promising class of electrically driven rectifier fluxpumps. With these rectifiers, current levels over 10 kA can be obtained with high efficiency.In part 2 a theoretical comparison between dynamos and transformer rectifiers will conclude the review.     

The Rise of Twitter in the Political Campaign: Searching for Intermedia Agenda‐Setting Effects in the Presidential Primary

Questions exist over the extent to which social media content may bypass, follow, or attract the attention of traditional media. This study sheds light on such dynamics by examining intermedia agenda‐setting effects among the Twitter feeds of the 2012 presidential primary candidates, Twitter feeds of the Republican and Democratic parties, and articles published in the nation's top newspapers. Daily issue frequencies within media were analyzed using time series analysis. A symbiotic relationship was found between agendas in Twitter posts and traditional news, with varying levels of intensity and differential time lags by issue. While traditional media follow candidates on certain topics, on others they are able to predict the political agenda on Twitter.     

Relating instance hardness to classification performance in a dataset: a visual approach

Machine Learning - Machine Learning studies often involve a series of computational experiments in which the predictive performance of multiple models are compared across one or more datasets. The...     

The effect of an oxide layer on the ohmicity of contacts to amorphous silicon

Surface oxide layers on CVD films of amorphous silicon can cause the metallic contacts to the films to be non-ohmic. Dipping an amorphous silicon sample in a solution of hydrofluoric acid prior to electrode deposition removes the oxide layer and permits the formation of ohmic contacts.