A Dynamic Localized Adjustable Force Field Method for Real-time Assistive Non-holonomic Mobile Robotics

Providing an assistive navigation system that augments rather than usurps user control of a powered wheelchair represents a significant technical challenge. This paper evaluates an assistive collision avoidance method for a powered wheelchair that allows the user to navigate safely whilst maintaining their overall governance of the platform motion. The paper shows that by shaping, switching and adjusting localized potential fields we are able to negotiate different obstacles by generating a more intuitively natural trajectory, one that does not deviate significantly from the operator in the loop desired-trajectory. It can also be seen that this method does not suffer from the local minima problem, or narrow corridor and proximity oscillation, which are common problems that occur when using potential fields. Furthermore this localized method enables the robotic platform to pass very close to obstacles, such as when negotiating a narrow passage or doorway

Investigation of structure-property relationships in systematic series of novel polymers

Solid state transitions in polymeric materials was associated with the onset of sub-molecular motions of the polymer chains. Although these were considered to be intramolecular in general, the local environment of the polymer molecule exerts a strong influence through, for example, the effects of crystallinity, polarity and diluents. The manner of specimen preparation and previous history also affect transitions. The transitions are considered to arise when sufficient free volume is available to permit the occurrence of these side chain and backbone reorientations. The glass transition is the principal transition of amorphous polymeric materials and is associated with the onset of long range segmental motion of the polymer backbone. The various types of shorter range motion occurring below the glass transition have been catalogued

Identifying Moderators Of Response To The Penn Resiliency Program: A Synthesis Study

To identify moderators of a cognitive-behavioral depression prevention program’s effect on depressive symptoms among youth in early adolescence, data from three randomized controlled trials of the Penn Resiliency Program (PRP) were aggregated to maximize statistical power and sample diversity (N = 1145). Depressive symptoms, measured with the Children’s Depression Inventory (CDI; Kovacs 1992), were assessed at six common time points over two-years of follow-up. Latent growth curve models evaluated whether PRP and control conditions differed in the rate of change in CDI and whether youth- and family-level characteristics moderated intervention effects. Model-based recursive partitioning was used as a supplementary analysis for identifying moderators. There was a three-way interaction of PRP, initial symptom severity, and intervention site on growth in depressive symptoms. There was considerable variability in PRP’s effects, with the nature of the interaction between PRP and initial symptom levels differing considerably across sites. PRP reduced depressive symptoms among youth with unmarried parents, but not among those with married parents. Finally, PRP’s effects differed across school grade levels. Although initial symptom severity moderated PRP’s effect on depressive symptoms, it was not a reliable indicator of how well the intervention performed, limiting its utility as a prescriptive variable. Our primary analyses suggest that PRP’s effects are limited to youth whose parents are unmarried. The small number of fifth grade students (n = 25; 2 %) showed a delayed and sustained intervention response. Our findings underscore the importance of evaluating site, family, and contextual characteristics as moderators in future studies

Review Of Interventions For Parental Depression From Toddlerhood To Adolescence

Because of the recurrent course, significant burden, and intergenerational impact of depression, there is a great need for interventions for depressed parents and their children. This article reviews eight interventions that 1) aim to impact the functioning and well-being of 18-month to 18-year old children of depressed parents and 2) have been evaluated in controlled studies. The interventions are described and the empirical evidence of their efficacy is reviewed and critiqued. Existing research points to several promising intervention strategies, such as psychoeducation about parental depression, addressing parenting in adult depression treatment, promoting positive parent-child interactions, and teaching coping skills to children. Common limitations of the research in this area are small sample sizes, homogenous samples, and lack of replication. Implementation problems within the mental healthcare system are highlighted. Multi-component interventions seem to be a promising approach to address the complex impact parental depression has on children and the parent-child relationship. This review illustrates the need for more research on intervention models that can be implemented with children at various developmental levels

Resiliency training in Indian children: A pilot investigation of the Penn Resiliency Program

© 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).This paper examines the effectiveness of the Penn Resiliency Program (PRP) in an urban Indian setting. The PRP is a program to prevent depression in early adolescence and has proved successful in changing children’s attributional style of life events. While the program has been successful in preventing symptoms of depression in Western populations, the current study explored whether this program could be effective with an Indian sample. The aim of the current study was twofold; first, to study the attributional style of early adolescents in India and identify negative effects (if any) and second, to gain insights in using the PRP as a tool to change explanatory styles in Indian children. A total of 58 children participated in the study (Intervention group n = 29 and Control group n = 29). An Analysis of Covariance comparing post-test scores on Children’s Attributional Style Questionnaire (CASQ) while controlling for baseline scores indicated that children in the intervention group exhibited a significant reduction in pessimistic explanatory style and an increase in optimistic orientation compared to children in the control group. This indicates that the program was effective in changing negative attribution styles among upper-class Indian school children. Future work may look into the longer impact of the program as well as further considerations into adapting the program for a middle class population

Assistive trajectories for human-in-the-loop mobile robotic platforms

Autonomous and semi-autonomous smoothly interruptible trajectories are developed which are highly suitable for application in tele-operated mobile robots, operator on-board military mobile ground platforms, and other mobility assistance platforms. These trajectories will allow a navigational system to provide assistance to the operator in the loop, for purpose built robots or remotely operated platforms. This will allow the platform to function well beyond the line-of-sight of the operator, enabling remote operation inside a building, surveillance, or advanced observations whilst keeping the operator in a safe location. In addition, on-board operators can be assisted to navigate without collision when distracted, or under-fire, or when physically disabled by injury

Precision lattice parameter measurements on some superconducting indium alloys

Imperial Users onl

Nuclear mutations affecting mitochondrial structure and function in Chlamydomonas

Wild type cells of the green alga Chlamydomonas reinhardtii can grow in the in the dark by taking up and respiring exogenously supplied acetate. Obligate photoautotrophic (dark dier, dk) mutants of this alga have been selected which grow at near wild type rates in the light, but rapidly die when transferred to darkness because of defects in mitochondrial structure and function. In crosses of the dk mutants to wild type, the majority of the mutants are inherited in a mendelian fashion, although two have been isolated which are inherited in a clearly nonmendelian fashion. Nine mendelian dk mutants have been analyzed in detail, and belong to eight different complementation groups representing eight gene loci. These mutants have been tentatively grouped into three classes on the basis of the pleiotropic nature of their phenotypic defects. Mutants in Class I have gross alterations in the ultrastructure of their mitochondrial inner membranes together with deficiencies in cytochrome oxidase and antimycin/rotenone-sensitive NADH-cytochrome c reductase activities. Mutants in Class II have a variety of less severe alterations in mitochondrial ultrastructure and deficiencies in cytochrome oxidase activity. Mutants in Class III have normal or near normal mitochondrial ultrastructure and reduced cytochrome oxidase activity. Eight of the nine mutants show corresponding reductions in cyanide-sensitive respiration

Structure-property relationships in low-temperature adhesives

Adhesive materials of aliphatic polyester, linear hydroxyl end-capped polybutadienes, or SBS block copolymers are studied with the objective to replace conventional partially aromatic end-reactive polyester-isocyanate adhesives that have shown embrittlemen