Examining working memory load and congruency effects on affordances and conventions

Although there is a debate about whether designers should draw a distinction between perceptual affordances and cultural conventions, there are few behavioral studies. We examined the impact of working memory load and expected button-to-action mapping congruency on affordances and conventions. The findings suggest both sides of the debate are correct. Learned conventions were found to structure responses towards expected actions, just like affordances, but affordance-based interactions were not affected by memory load while convention-based actions were. Therefore, designers ought to employ perceptual affordances when possible and when not feasible they ought to reuse established conventions. Additionally, evidence is presented that violating expected affordance-based and convention-based button-to-action mappings caused a similar performance cost. We believe that after the initial learning period, conventions play a critical role in the perception of a design’s available actions just as perceptual affordances do.     

Enhanced problem translation and short-term memory: Components of mathematical talent.

The performance of mathematically talented 12- and 13-year-olds on various cognitive tasks was compared with that of average-ability youth, verbally talented youth, and college students. In Experiment 1, the hypothesis that mathematical talent includes enhanced problem-translation skills was supported: The mathematically talented students were better than other groups at writing equations expressing complex relationships. Although the mathematically talented group outperformed their average-ability peers, they were no better than the verbally talented group or the college students in rewriting and recalling the propositions in an algebra story problem. In Experiment 2, the hypothesis that mathematical talent includes enhanced ability to represent and manipulate information in short-term memory was strongly supported: the mathematically talented youth outperformed the other youth and, in most cases, performed as well as or better than the college students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Localization of frontotemporal dementia with parkinsonism in an Australian kindred to chromosome 17q21-22

An Australian family with autosomal dominant presenile nonspecific dementia was recently described. The disease results in behavioral changes, usually disinhibition, followed by the onset of dementia accompanied occasionally by parkinsonism. Twenty-eight affected individuals were identified with an age of onset of 39 to 66 years (mean, 53 +/- 8.9 years). We mapped the disease locus to an approximately 26-cM region of chromosome 17q21-22 with a maximum two-point LOD score of 2.87. Affected individuals share a common haplotype between markers D17S783 and D17S808. This region of chromosome 17 contains the loci for several neurodegenerative diseases that lack distinctive pathological features, suggesting that these dementias, collectively referred to as frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), are caused by mutations in the same gene. The entire coding region of five genes, mapped to the FTDP-17 candidate region, were also sequenced. This analysis included the microtubule-associated protein tau that is the major component of the paired helical filaments observed in Alzheimer's disease. No pathogenic mutations were identified in either the tau gene or in any of the other genes analyzed.     

Semantic and spatial components of selective attention.

Semantic and spatial effects on selective processing were examined. A prime presented 250 ms or 1,000 ms before a pair of masked words was related to 1 of the words on 1/3 of the trials. Although Experiments 1 and 2 required report of both words, processing was selective; typically, just 1 word could be reported. In Experiment 1, reported words were more often top words, showing spatial selectivity, and more often words related to the prime, showing semantic selectivity. Experiment 2 included to-be-ignored peripheral cues 50 ms before the pair. Related words were reported more often at both delays, and cuing produced an additive benefit at 1,000 ms. Experiment 3 required report of just the cued word and included 100-ms cues. Cued words were reported more often, especially at 1,000 ms and with 100-ms cues, but semantic selectivity also occurred. Selectivity via semantic priming and via location reflect separate attentional mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence diagnostics for multivariate GARCH processes

This article presents diagnostics for identifying influential observations when estimating multivariate generalized autoregressive conditional heteroscedasticity (GARCH) models. We derive influence diagnostics by introducing minor perturbations to the conditional variances and covariances. The derived diagnostics are applied to a bivariate GARCH model of daily returns of the S&P500 and IBM. We find that univariate diagnostic procedures may be unable to identify the influential observations in a multivariate model. Importantly, the proposed curvature‐based diagnostic identified influential observations where the correlation between the two series had a major change. These observations were not identified as influential using the univariate diagnostics for each asset separately. When estimating the bivariate GARCH model allowing for weights at influential observations, we found that the time‐varying correlations behaved differently from that implied by the model ignoring influential observations. The application therefore highlights the importance of extending univariate diagnostic procedures to multivariate settings.     

机动战士高达战斗行动

3月15日，NBGI公开了名为《机动战士高达战斗行动》的高达游戏新作。比较有趣的是本作不仅由PS3独占．更是一款完全基于SonyEntertainmentNetwork的网络游戏。说到网战。很容易让人联想到去年年底发售的《机动战士高达EXTREMEVS．》，其不仅具备出色的手感和画面，同样也对应SEN联机对战。让众多高...     

The IPO window of opportunity for digital product and service firms

Recognizing the window of opportunity to go public for digital product and service (DPS) firms is especially critical because they have high fixed-to-variable cost (FCVC) ratios and winner-take-all industry competition. Too early and their very risky nature means a steep discount to their stock. Too late and they may not be able to sell stock or it may be too late to take advantage of a new product or service. We find that the size of the run-up in stock price at the IPO is higher (lower) for DPS firms the earlier (later) they go public and significantly more than for traditional firms. We also find that the DPS firms that go public earlier or later outside the window of opportunity are more likely to fail. This result is also stronger for DPS firms than for traditional firms.     

Teaching students to design secure systems

The pedagogy used to teach computer security to students new to the field is usually handled by a one- or two-course augmentation to an existing curriculum. Furthermore, the courses tend to be technology-centric and often do not uncover the underlying processes that students can transfer to new situations. In this article, we look more closely at determining an appropriate scope and sequence for information assurance (IA) and briefly describe a project whose goal is the articulation of an IA curriculum.