On optimal smoothing and derivative estimation from noisy displacement data in biomechanics

Estimating derivatives from noisy displacement data is a notoriously ill-posed problem in signal processing and biomechanics. Following the work of Wood and Jennings (1978) and Hatze (1979, 1981), the present paper describes the use of optimally regularized, natural quintic splines for estimating smoothed positions, velocities, and accelerations from equidistantly sampled, noisy position measurements. It appears that the nature of the boundary conditions of the data is of some importance, since various algorithms used hitherto result in artefacts throughout the data if the true derivatives at the record ends differ significantly from zero. Natural quintic splines do not suffer from this disadvantage below the third derivative.The ill-posed character of movement analysis has some interesting implications for movement synthesis and optimization, similar to the indeterminacy of muscular co-contraction from merely external, biomechanical measurements.     

The interpretation of universal affirmative propositions

It is proposed that All F are G is often given a ‘structure-neutral’ interpretation, as All, F, G, lacking a subject-predicate distinction. In the first experiment, children aged 6–7–8, and 11–12, and adults, acted out instructions like “Make a building in which all the yellow blocks are square”. The experiment demonstrated the dominance in children and decline with age of structure-neutral interpretations. In a second experiment, with the same age groups, propositions of the form All F are G, varying as to the factual inclusion relations expressed, were presented as the major premises of syllogistic items. The results indicated the presence of structure-neutral interpretations under some circumstances in adults as well as children, and also demonstrated the existence in all subjects of a ‘pragmatic processing’ mode that becomes less obligatory with age. In pragmatic interpretations, meaning is determined by previously known factual relations between the things which the words represent, rather than by grammatical relations between the words themselves.     

The response of day and night wetting children and children who wet only at night to retention control training and the enuresis alarm

Forty-five children with night wetting only (NW) and 30 children with day and night wetting (DNW) were randomly assigned to 2 treatment groups: alarm only and alarm preceded by 4 weeks of retention control training (R.C.T.). Fewer children became dry at night in the DNW group than the NW group and DNW children relapsed earlier following treatment. The enuresis alarm was far superior to R.C.T. in reducing night wetting in both enuretic groups. It also reduced day wetting in some of the DNW children. Children who became dry in the NW group did not show significant changes in functional bladder capacity. Although changes in functional bladder capacity were seen in the DNW children who became dry, changes were only noticeable once dryness had been achieved.     

The use of a self-control package to enhance temporal generality of a parent training program

The purpose of the present study was to examine the effectiveness of a self-control package in enhancing temporal generality of a parent training program. Sixteen mothers and their clinic-referred noncompliant children were assigned to either a parent training alone group, or a parent training plus self-control group. All mother-child dyads were treated individually by teaching the mother to reward compliance and other prosocial behavior, and to use time-out for noncompliance. In addition, mothers who also received self-control training learned to self-monitor their use of their new parenting skills and to reinforce themselves for use of the skill during a 2 month follow-up period. Assessment consisted of four home observations by independent observers prior to treatment, after treatment, and at a 2 month follow-up. The data indicated that the children in the parent training plus self-control group were significantly more compliant and less deviant at the 2 month follow-up than the children in the parent training alone group. Parental behavior did not differ between the two groups at the follow-up.