Boundedness conjecture for an output error adaptive algorithm

This paper compares conditions for instability with conditions for global asymptotic stability of a discretetime output error adaptive estimation algorithm. This comparison leads to a boundedness conjecture which states that all signals within this adaptive system as well as the output error and parameter estimates remain globally bounded for all time despite any unstable behaviour. The investigation into the stability properties of this algorithm begins with a global stability criterion applied to a transfer function which is not strictly positive real. This criterion states that for large enough adaptation gain and/or input signal magnitude the system will be asymptotically stable. Then a local result is applied which states that for small enough adaptation gain and/or input signal magnitude the same system is unstable. The result is a bifurcation due to the decrease of the adaptation gain and/or input signal magnitude as the system goes from asymptotic stability to instability which remains bounded. The results suggested by the computer simulations are verified by an exact analysis of a linearized periodic version of the adaptive system.     

Randomized trial of MST and ARC in a two-level evidence-based treatment implementation strategy.

Objective: A randomized trial assessed the effectiveness of a 2-level strategy for implementing evidence-based mental health treatments for delinquent youth. Method: A 2 × 2 design encompassing 14 rural Appalachian counties included 2 factors: (a) the random assignment of delinquent youth within each county to a multisystemic therapy (MST) program or usual services and (b) the random assignment of counties to the ARC (for availability, responsiveness, and continuity) organizational intervention for implementing effective community-based mental health services. The design created 4 treatment conditions (MST plus ARC, MST only, ARC only, control). Outcome measures for 615 youth who were 69% male, 91% Caucasian, and aged 9–17 years included the Child Behavior Checklist and out-of-home placements. Results: A multilevel, mixed-effects, regression analysis of 6-month treatment outcomes found that youth total problem behavior in the MST plus ARC condition was at a nonclinical level and significantly lower than in other conditions. Total problem behavior was equivalent and at nonclinical levels in all conditions by the 18-month follow-up, but youth in the MST plus ARC condition entered out-of-home placements at a significantly lower rate (16%) than youth in the control condition (34%). Conclusions: Two-level strategies that combine an organizational intervention such as ARC and an evidence-based treatment such as MST are promising approaches to implementing effective community-based mental health services. More research is needed to understand how such strategies can be used effectively in a variety of organizational contexts and with other types of evidence-based treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detecting atrial fibrillation using spatial precision

Discusses measuring local activation direction variability using short segment lengths to quickly differentiate fibrillation from regular rhythms. It is concluded that the spatial precision of local activation direction shows promise as a potential discriminator of atrial fibrillation from regular atrial rhythms. For the authors' study set, excellent discrimination of atrial fibrillation from regular rhythms was achieved by spatial precision using segment lengths as short as 20 activations. The authors would expect that this method would be even more accurate using permanently implanted electrodes and could be implemented in real-time using four-electrode elements, and may be applicable in the ventricle as well     

Clinical supervision in treatment transport: Effects on adherence and outcomes.

This nonexperimental study used mixed-effects regression models to examine relations among supervisor adherence to a clinical supervision protocol, therapist adherence, and changes in the behavior and functioning of youths with serious antisocial behavior treated with an empirically supported treatment (i.e., multisystemic therapy [MST]) 1 year posttreatment. Participants were 1,979 youths and families treated by 429 clinicians across 45 provider organizations in North America. Four dimensions of clinical supervision were examined. Mixed-effects regression model results showed that one dimension, supervisor focus on adherence to treatment principles, predicted greater therapist adherence. Two supervision dimensions, Adherence to the Structure and Process of Supervision and focus on Clinician Development, predicted changes in youth behavior. Conditions required to test hypothesized mediation by therapist adherence of supervisor adherence effects on youth outcomes were not met. However, direct effects of supervisor and therapist adherence were observed in models including both of these variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Caregiver-Therapist Ethnic Similarity Predicts Youth Outcomes From an Empirically Based Treatment.

The effects of caregiver-therapist ethnic similarity on youth outcomes from multisystemic therapy (MST), as implemented in dissemination sites, were examined. Consistent with hypotheses, findings confirmed that youths whose caregivers were ethnically matched with their therapists demonstrated greater decreases in symptoms, longer times in treatment, and increased likelihood of discharge for meeting treatment goals relative to youths whose caregivers and therapists were not ethnically matched. In addition, for youths whose caregivers were of mixed ethnic heritage, caregiver-therapist ethnic match was associated with greater improvements in psychosocial functioning. Ethnic match effects on both treatment length and discharge success were partially mediated by therapist adherence to MST. This study shows the importance of examining the effects of both client and therapist ethnicity on outcomes from empirically based treatments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decentralized Inventory Control for Large-Scale Reverse Supply Chains: A Computationally Tractable Approach

In this paper, we consider a new inventory control technique for large-scale supply chains including repairs. The part flow is bidirectional with broken parts propagated upstream for repair. It is well known that available optimization techniques for inventory control for bidirectional stochastic supply chains are computationally intractable and also necessitate several simplifying assumptions. In contrast, the proposed approach is an adaptive scheme that scales well to practically interesting large-scale multi-item supply chains. Furthermore, practical issues such as stochastic transport delays, manufacturing times, and repair times and probabilistic characterization of part repair success are handled in a unified framework. The control scheme is based on a hierarchical two-level architecture that comprises an adaptive set point generator and a lower-level order-up-to policy. An application to aircraft supply chains involving multiple original equipment manufacturers (OEMs), depots, bases, squadrons, and planes is also investigated.