72,754 research outputs found
Pure Exploration with Multiple Correct Answers
We determine the sample complexity of pure exploration bandit problems with
multiple good answers. We derive a lower bound using a new game equilibrium
argument. We show how continuity and convexity properties of single-answer
problems ensures that the Track-and-Stop algorithm has asymptotically optimal
sample complexity. However, that convexity is lost when going to the
multiple-answer setting. We present a new algorithm which extends
Track-and-Stop to the multiple-answer case and has asymptotic sample complexity
matching the lower bound
The Simulator: Understanding Adaptive Sampling in the Moderate-Confidence Regime
We propose a novel technique for analyzing adaptive sampling called the {\em
Simulator}. Our approach differs from the existing methods by considering not
how much information could be gathered by any fixed sampling strategy, but how
difficult it is to distinguish a good sampling strategy from a bad one given
the limited amount of data collected up to any given time. This change of
perspective allows us to match the strength of both Fano and change-of-measure
techniques, without succumbing to the limitations of either method. For
concreteness, we apply our techniques to a structured multi-arm bandit problem
in the fixed-confidence pure exploration setting, where we show that the
constraints on the means imply a substantial gap between the
moderate-confidence sample complexity, and the asymptotic sample complexity as
found in the literature. We also prove the first instance-based
lower bounds for the top-k problem which incorporate the appropriate
log-factors. Moreover, our lower bounds zero-in on the number of times each
\emph{individual} arm needs to be pulled, uncovering new phenomena which are
drowned out in the aggregate sample complexity. Our new analysis inspires a
simple and near-optimal algorithm for the best-arm and top-k identification,
the first {\em practical} algorithm of its kind for the latter problem which
removes extraneous log factors, and outperforms the state-of-the-art in
experiments
Social Competence Treatment after Traumatic Brain Injury: A Multicenter, Randomized, Controlled Trial of Interactive Group Treatment versus Non-Interactive Treatment
Objective
To evaluate the effectiveness of a replicable group treatment program for improving social competence after traumatic brain injury (TBI).
Design
Multicenter randomized controlled trial comparing two methods of conducting a social competency skills program, an interactive group format versus a classroom lecture.
Setting
Community and Veteran rehabilitation centers.
Participants
179 civilian, military, and veteran adults with TBI and social competence difficulties, at least 6 months post-injury.
Experimental Intervention
Thirteen weekly group interactive sessions (1.5 hours) with structured and facilitated group interactions to improve social competence.
Alternative (Control) Intervention
Thirteen traditional classroom sessions using the same curriculum with brief supplemental individual sessions but without structured group interaction.
Primary Outcome Measure
Profile of Pragmatic Impairment in Communication (PPIC), an objective behavioral rating of social communication impairments following TBI.
Secondary Outcomes
LaTrobe Communication Questionnaire (LCQ), Goal Attainment Scale (GAS), Satisfaction with Life Scale (SWLS), Post-Traumatic Stress Disorder Checklist – (PCL-C), Brief Symptom Inventory 18 (BSI-18), Scale of Perceived Social Self Efficacy (PSSE).
Results
Social competence goals (GAS) were achieved and maintained for most participants regardless of treatment method. Significant improvements in the primary outcome (PPIC) and two of the secondary outcomes (LCQ and BSI) were seen immediately post-treatment and at 3 months post-treatment in the AT arm only, however these improvements were not significantly different between the GIST and AT arms. Similar trends were observed for PSSE and PCL-C.
Conclusions
Social competence skills improved for persons with TBI in both treatment conditions. The group interactive format was not found to be a superior method of treatment delivery in this study
- …