Classroom Presenter: Enhancing Interactive Education with Digital Ink

Classroom Presenter is a Tablet PC-based interaction system that supports the sharing of digital ink on slides between instructors and students. Initial deployments show that using the technology can achieve a wide range of educational goals and foster a more participatory classroom environment.     

Practical modelling of micro combined heat and power applications for local authority district heating schemes

The primary purposes of this paper are to describe a practical model which can be used to assist economic evaluation of district heating proposals, with particular reference to potential micro combined heat and power (CHP) applications, and to discuss the results of applying this model to a proposal for a particular scheme. The problems of realistic simulation of demand patterns, and the sensitivity of micro-CHP project values to scale, fuel prices, differential purchase/selling tariffs for electricity, duty cycle and plant utilization factors are discussed. Of several options, two were shown to be economically viable, relative to existing methods of supply (gas-fired boilers); however, the margin of benefit is small relative to wisely chosen modern boiler installations. A brief discussion of alternative methods of finance is provided; ceteris paribus, the proposed scheme would not be likely to attract venture capital from would-be lease-hire agencies. There is scope however for pilot schemes, whose results could be used to define more closely the limits of uncertainty of, for example, annual availability and duty cycle influences on the cost economics of operations.     

The spatial focus of attention is controlled at perceptual and cognitive levels.

Selective attention has been hypothesized to reduce distractor interference at both perceptual and postperceptual levels (Lavie, 2005), respectively, by focusing perceptual resources on the attended location and by blocking at postperceptual levels distractors that survive perceptual selection. This study measured the impact of load on these selection mechanisms using a flanker paradigm (Eriksen & St. James, 1986) and indexing distractor interference as a function of separation. It distinguished changes in the extent of focus of the distractor-interference function of separation (reflecting perceptual selection) from changes in the amplitude of distractor interference not accompanied by changes in focus (reflecting postperceptual selection). It showed that: (1) the spatial profile of perceptual resources is shaped like a “Mexican hat” (Müller et al., 2005); (2) increasing perceptual load focuses perceptual resources (Caparos & Linnell, 2009); (3) increasing cognitive load defocuses perceptual resources; and (4) participants with reduced working-memory span show reduced postperceptual blocking of distractors. While these findings are consistent with two levels of selective attention, they show that the first perceptual level is affected not only by perceptual but also by cognitive-control mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual and cognitive load interact to control the spatial focus of attention.

Caparos and Linnell (2009, 2010) used a variable-separation flanker paradigm to show that (a) when cognitive load is low, increasing perceptual load causes spatial attention to focus and (b) when perceptual load is high, decreasing cognitive load causes spatial attention to focus. Here, we tested whether the effects of perceptual and cognitive load on spatial focus remain when, respectively, cognitive load is high and perceptual load is low. We found that decreasing cognitive load only causes spatial attention to focus when perceptual load is high and the stimulus encourages this. Moreover, and contrary to the widely held assumption that perceptual load focuses attention automatically (Lavie, Hirst, de Fockert, & Viding, 2004), perceptual load exerts its focusing effect only with the engagement of cognitive resources when cognitive load is low. In sum, perceptual and cognitive mechanisms exert interacting effects and operate in concert to focus spatial attention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Top-down-driven grouping overrules the central attentional bias.

A central bias in spatial selection has been proposed to explain the decreasing search efficiency with increasing target eccentricity that results when distractors can occur closer to fixation than the target (J. M. Wolfe, P. O'Neill, & S. C. Bennett, 1998). The authors found evidence for such a bias using an odd-man-out variant of conjunction search. However, the bias was absent for the same displays when the identity of the odd-man-out target was known in advance. The authors propose that (a) top-down knowledge of a target feature supports grouping on this feature and (b) grouping links a peripheral target to central distractors expressing the same feature, increasing the attentional weighting afforded to the target and, consequently, facilitating its detection. The effects are independent of bottom-up priming effects occurring across trials. Thus, feature-based grouping can be driven top-down and can overrule the central bias in spatial selection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)