Factorial multi-task learning : a Bayesian nonparametric approach

Multi-task learning is a paradigm shown to improve the performance of related tasks through their joint learning. However, for real-world data, it is usually difficult to assess the task relatedness and joint learning with unrelated tasks may lead to serious performance degradations. To this end, we propose a framework that groups the tasks based on their relatedness in a subspace and allows a varying degree of relatedness among tasks by sharing the subspace bases across the groups. This provides the flexibility of no sharing when two sets of tasks are unrelated and partial/total sharing when the tasks are related. Importantly, the number of task-groups and the subspace dimensionality are automatically inferred from the data. To realize our framework, we introduce a novel Bayesian nonparametric prior that extends the traditional hierarchical beta process prior using a Dirichlet process to permit potentially infinite number of child beta processes. We apply our model for multi-task regression and classification applications. Experimental results using several synthetic and real datasets show the superiority of our model to other recent multi-task learning methods. Copyright 2013 by the author(s).

Efficacy of Cognitive Processes in Young People with High-Functioning Autism Spectrum Disorder Using a Novel Visual Information-Processing Task

Autism spectrum disorders (ASD) are characterised by a unique pattern of preserved abilities and deficits within and across cognitive domains. The Complex Information Processing Theory proposes this pattern reflects an altered capacity to respond to cognitive demands. This study compared how complexity induced by time constraints on processing affect cognitive function in individuals with ASD and typically-developing individuals. On a visual information-processing task, the Subtle Cognitive Impairment Test, both groups exhibited sensitivity to time-constraints. Further, 65 % of individuals with ASD demonstrated deficits in processing efficiency, possibly attributable to the effects of age and clinical comorbidities, like attention deficit hyperactivity disorder. These findings suggest that for some ASD individuals there are significant impairments in processing efficiency, which may have implications for education and interventions. © 2014 Springer Science+Business Media New York.

Staging systems in bipolar disorder: an International Society for Bipolar Disorders Task Force report

We discuss the rationale behind staging systems described specifically for bipolar disorders. Current applications, future directions and research gaps in clinical staging models for bipolar disorders are outlined.

Sleep restriction during simulated wildfire suppression: effect on physical task performance

OBJECTIVES: To examine the effects of sleep restriction on firefighters' physical task performance during simulated wildfire suppression. METHODS: Thirty-five firefighters were matched and randomly allocated to either a control condition (8-hour sleep opportunity, n = 18) or a sleep restricted condition (4-hour sleep opportunity, n = 17). Performance on physical work tasks was evaluated across three days. In addition, heart rate, core temperature, and worker activity were measured continuously. Rate of perceived and exertion and effort sensation were evaluated during the physical work periods. RESULTS: There were no differences between the sleep-restricted and control groups in firefighters' task performance, heart rate, core temperature, or perceptual responses during self-paced simulated firefighting work tasks. However, the sleep-restricted group were less active during periods of non-physical work compared to the control group. CONCLUSIONS: Under self-paced work conditions, 4 h of sleep restriction did not adversely affect firefighters' performance on physical work tasks. However, the sleep-restricted group were less physically active throughout the simulation. This may indicate that sleep-restricted participants adapted their behaviour to conserve effort during rest periods, to subsequently ensure they were able to maintain performance during the firefighter work tasks. This work contributes new knowledge to inform fire agencies of firefighters' operational capabilities when their sleep is restricted during multi-day wildfire events. The work also highlights the need for further research to explore how sleep restriction affects physical performance during tasks of varying duration, intensity, and complexity.

Task-specific effects of modular body armor.

Eleven recreationally active males performed 11 circuits of military work, wearing torso armor on one occasion, and full armor on another. Performance was measured by the time taken to complete individual tasks, and the overall time to completion (TTC) for each circuit. Heart rate, intestinal temperature, ratings of perceived exertion (RPE), and thermal sensation were recorded after each circuit. Participants' circuit TTC was no different between conditions; however, specific tasks were differentially impeded by the two armor configurations. Vaulting and crawling were significantly slower (0.28 ± 0.06 and 0.55 ± 0.26 seconds) in full armor; however, box lifting and shooting were significantly slower (0.36 ± 0.18 and 0.86 ± 0.23 seconds) when wearing torso armor. Heart rate and core temperature were significantly higher during the full armor trial (5 ± 1 beats · min(-1) and 0.22 ± 0.03 °C). Similarly, RPE and thermal sensation were significantly higher (1 ± 0 and 0.5 ± 0.0) during the full armor condition. Military tasks were differentially impaired by the armor configurations used, which suggests a need to explore role-specific armor for military personnel. Physiological and perceptual responses were elevated in full armor, which could be exacerbated during longer periods of work or in hot conditions.

Determinants and economic consequences of voluntary disclosure of internal control weaknesses in China

This paper investigates the determinants and economic consequences of disclosure of internal control weaknesses (ICWs) by Chinese listed firms under the voluntary disclosure regime over 2010-2011. We find that the probability of firms disclosing ICWs is not only associated with firm characteristics such as profitability, age and business complexity, but is also strongly related to the unique attributes of corporate governance and ownership structure in Chinese listed firms, e.g. the independence of the supervisory board, political connections, concentration of the top 3 shareholders' ownership and tradability of shares.Our results show that the severity of the ICWs disclosed is negatively and significantly associated with earnings response coefficients (ERCs), and audit assurance of ICRs has a significant moderating effect on the relationship between ICWs and ERCs. Our research adds further evidence to support the implementation of SOX-type regulations globally.

Does student engagement in self-assessment calibrate their judgement over time?

One of the implicit aims of higher education is to enable students to become better judges of their own work. This paper examines whether students who voluntarily engage in self-assessment improve in their capacity to make those judgements. The study utilises data from a web-based marking system that provides students with the opportunity to assess themselves on each criterion for each assessment task throughout a programme of study. Student marks were compared with those from tutors to plot changes over time. The findings suggest that overall students’ judgements do converge with those of tutors, but that there is considerable variation across achievement levels, with weaker students showing little improvement. Whilst the study is limited by the exigencies of voluntary participation and thus consequential gaps in the data set, it shows how judgement over time can be demonstrated and points to the potential for more systematic interventions to improve students’ judgements. It also illustrates the use of the web-based marking and feedback software (ReView) that has considerable utility in aiding self-assessment research.

The calibration of student judgement through self-assessment: disruptive effects of assessment patterns

Can extended opportunities for self-assessment over time help students develop the capacity to make better judgements about their work? Using evidence gathered through students' voluntary self-assessment of their performance with respect to assessment tasks in two different disciplines at two Australian universities, the paper focuses on the effects of sequences of units of study and the use of different types of assessment task (written, oral, analysis, and project) in the development of student judgement. Convergence between student criteria-based gradings of their own performance in units of study and those allocated by tutors was analysed to explore the calibration of students' judgement over time. First, it seeks to replicate analyses from an earlier smaller-scale study to confirm that students' judgements can be calibrated through continuing opportunities for self-assessment and feedback. Second, it extends the analysis to coherently designed sequences of units of study and explores the effects of different types of assessment. It finds that disruptive patterns of assessment within a sequence of subjects can reduce convergence between student and tutor judgements.