University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

Neuroanatomical and cognitive correlates of adult age differences in acquisition of a perceptual-motor skill.

Abstract: The objective of this study was to examine age differences in procedural learning and performance in conjunction with differential aging of central nervous system (CNS) structures. Sixty-eight healthy volunteers (age 22-80) performed a pursuit rotor task (four blocks of 20 15-second trials each). Volumes of the cerebellar hemispheres, neostriatum, prefrontal cortex, and hippocampus were measured from Magnetic Resonance (MR) images. Improvement in pursuit rotor performance was indexed by increase in time on target (TOT). A general improvement trend was evident across the blocks of trials. Overall, younger participants showed significantly longer TOT. The rate of improvement was age-invariant during the initial stages of skill acquisition but became greater in middle-aged participants as the practice progressed. When the influences of regional brain volumes were taken into account, the direct age effect on mean TOT measured during the first day of practice disappeared. Instead, reduced volumes of the cerebellar hemispheres and the putamen and poorer performance on nonverbal working memory tasks predicted shorter TOT. In contrast, neither the volume of the caudate and the hippocampus, nor verbal working memory showed association with motor performance. Pursuit rotor performance at the later stages of practice was unrelated to the reduction in putamen volume and was affected directly by age, cerebellar volume, and nonverbal working memory proficiency. We conclude that in a healthy population showing no clinical signs of extrapyramidal disease, age-related declines in procedural learning are associated with reduced volume of the cerebellar hemispheres and lower nonverbal working memory scores. During initial stages of skill acquisition, reduced volume of the putamen is also predictive of poorer performance.

AVOIDIT: A Cyber Attack Taxonomy

Abstract: Cyber-attacks have greatly increased over the years, and the attackers have progressively improved in devising attacks towards specific targets. To aid in identifying and defending against cyber-attacks we propose a cyber attack taxonomy called AVOIDIT (Attack Vector, Operational Impact, Defense, Information Impact, and Target). We use five major classifiers to characterize the nature of an attack: classification by attack vector, classification by operational impact, classification by defense, classification by informational impact, and classification by attack target. Classification by defense is oriented towards providing information to the network administrator regarding attack mitigation or remediation strategies. Contrary to the existing taxonomies, AVOIDIT efficiently classifies blended attacks. We further propose an efficient cause, action, defense, analysis, and target (CADAT) process used to facilitate attack classification. AVOIDIT and CADAT are used by an issue resolution system (IRS) to educate the defender on possible cyber-attacks and the development of potential security policies. We validate the proposed AVOIDIT taxonomy using cyber-attacks scenarios and highlight future work intended to simulate AVOIDIT's use within the IRS.

CO exposure, puff topography, and subjective effects in waterpipe tobacco smokers.

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Location of foreign manufacturers in China: Agglomeration economies and country of origin effects

Abstract: Using data from China, this article finds that agglomeration economies derived from the clustering of manufacturing and foreign investment activities, combined with better access to markets, influence the location of foreign manufacturers. Foreign enterprises are attracted to cities with investment incentives, but they avoid high labour cost locations. The locational patterns also suggest country of origin effects. American, Hong Kong and Taiwanese manufacturers tend to value access to domestic markets, while Japanese investors favour port cities. Further analysis indicates the presence of origin of country effects at the sectoral level.

Automatic Detection of Learner's Affect From Gross Body Language

Abstract: We explored the reliability of detecting learners' affect by monitoring their gross body language (body position and arousal) during interactions with an intelligent tutoring system called AutoTutor. Training and validation data on affective states were collected in a learning session with AutoTutor, after which the learners' affective states (i.e., emotions) were rated by the learner, a peer, and two trained judges. An automated body pressure measurement system was used to capture the pressure exerted by the learner on the seat and back of a chair during the tutoring session. We extracted two sets of features from the pressure maps. The first set focused on the average pressure exerted, along with the magnitude and direction of changes in the pressure during emotional experiences. The second set of features monitored the spatial and temporal properties of naturally occurring pockets of pressure. We constructed five data sets that temporally integrated the affective judgments with the two sets of pressure features. The first four datasets corresponded to judgments of the learner, a peer, and two trained judges, whereas the final data set integrated judgments of the two trained judges. Machine-learning experiments yielded affect detection accuracies of 73%, 72%, 70%, 83%, and 74%, respectively (chance = 50%) in detecting boredom, confusion, delight, flow, and frustration, from neutral. Accuracies involving discriminations between two, three, four, and five affective states (excluding neutral) were 71%, 55%, 46%, and 40% with chance rates being 50%, 33%, 25%, and 20%, respectively.