Design and control of remote manipulators

Results of investigations on vibrational modes of manipulators revealed: (1) any arbitrary manipulator may be analyzed for its small motion compliances; (2) a simulation of the Martin-Marietta shuttle boom with a 65,000 lb. payload attached, indicated three natural frequencies; and (3) simulations can be made of rigid limbs and flexible joints as well as for flexible limbs and locked joints and combinations thereof. Trajectories for arms were determined so that some integral criterion such as integral of kinetic energy or control torque magnitude is minimized over a motion of the arm. Experiments performed to evaluate various TV displays in conjunction with manipulator control modes showed that when mounted directly to the manipulator control arm and arranged to look approximately along the arm to the hand the operator could perform the task almost as quickly as when viewing the task directly

Tradeoffs in manipulator structure and control. Part 1: Summary

The study of various aspects of manipulator design and control is summarized, focusing on the interaction of the structure's flexible dynamics and the dynamics of the joint control system, including specific information on modeling and design, modal analysis and control, and the flexible manipulator analysis computer program, FMAP

Psychometric Support for the Ownership in Exercise and Empowerment in Exercise Scales

This study’s purpose was to examine the psychometric properties of two new scales developed to quantitatively measure participants’ ownership in exercise classes and empowerment with respect to exercise. These two outcome measures will compliment Achievement Goal Perspective Theory (AGPT) grounded research to better understand participants’ exercise experiences. College exercise class participants (N = 414; Mage = 21.25 years; 67% female) completed the survey during the last two weeks of a semester. Measurement invariance was assessed by a two-group (i.e., male and female) confirmatory factor analysis and used Mplus’ cluster option to account for the data’s nested nature. Strong invariance was achieved, which provided psychometric evidence for the ownership and empowerment in exercise measures. Additional validity support was provided by the ownership and empowerment latent relationships aligning with the researchers a priori hypotheses. These results provide preliminary validity evidence for the Ownership in Exercise and Empowerment in Exercise Scales

National Franchise Members’ Perceptions of the Exercise Psychosocial Environment, Ownership, & Satisfaction

The purpose of this study was to examine the relationship between: a) the motivational climate developed by a national exercise franchise and b) members’ sense of ownership in and enjoyment of exercise. Members of a national exercise franchise (N=5,329) were surveyed to learn their views on the motivational climate (autonomy supportive, caring, task- and ego-involving), exercise class ownership, and class enjoyment. Mean scale scores revealed this national exercise franchise succeeded in developing a high caring (M = 4.60 ± .68), task-involving (M = 4.04 ± .62), and autonomy supportive (M = 5.98 ± 1.00) climate, and low ego-involving (M = 1.79 ± .69) climate. The members also reported high perceptions of ownership (M = 4.21 ± .78) within and enjoyment (M = 6.50 ± .91) of the exercise program. Structural equation modeling (SEM), theory-driven regression analyses supported the hypothesis that the psychosocial environment experienced by members predicted their reported ownership and enjoyment. Specifically, members’ ownership was significantly positively predicted by their perceptions of the environment as task-involving and autonomy supportive, and negatively predicted by their perceptions of the environment as ego-involving. Members’ enjoyment was significantly positively predicted by their perceptions of the environment as caring, task-involving, and autonomy supportive, while negatively predicted by their ego-involving climate perceptions. A large, national fitness organization is capable of promoting their franchisees’ consistent fostering of a highly caring, autonomy supportive, task-involving, and low ego-involving environment. Developing this climate was associated with members reporting a greater sense of ownership and enjoyment of their exercise experience

Plasma Physics

Contains reports on three research projects.U. S. Atomic Energy Commission (Contract AT(30-1)-1842)U. S. Air Force (Electronic Systems Division) under Contract AF19(604)-599

A Motivational Climate Intervention and Exercise-Related Outcomes: A Longitudinal Perspective

While researchers have suggested that the social context in exercise settings is linked to individuals’ physical activity motivation and potential exercise-related outcomes, few research designs have examined the nuance of those relationships. Moreover, interventions targeting the social context of exercise settings are sparse, so the potential impact of staff training on members’ motivation to exercise are not well known. Drawing from two major motivation theories, achievement goal perspective theory and self-determination theory, this study considered an intervention with fitness center staff from the members’ perspectives. Members completed a survey before and after an intervention designed to help staff create a high caring, task-involving, and low ego-involving motivational climate. Using a half-longitudinal structural equation model, participants’ perceptions of the motivational climate, basic psychological needs, exercise motivation, and exercise experiences (including commitment to exercise, life satisfaction, body image) were modeled pre-post intervention. The model revealed significant latent mean differences for post-intervention constructs, with participants experiencing a more positive motivational climate, higher competence and relatedness, intrinsic motivation, commitment, life satisfaction, and body image. The final mediation model demonstrated tenable fit, with perceptions of climate having significant, direct and indirect effects on commitment, life satisfaction, and body image. Our study supports that the motivational climate contributes to an optimal social context for exercise where basic psychological needs are nurtured, intrinsic motivation is fostered, and individuals experience well-being benefits, including increased life satisfaction. Further, short and targeted training meetings with fitness center staff can result in members’ perceiving a significant change in the motivational climate

The Influence of Instructor Behaviors and the Perceived Motivational Climate on Undergraduate Students’ Experiences in College STEM Laboratories

Biology laboratory instructors play a key role in creating an optimal environment where college students try hard and enjoy their classroom experiences. This study used achievement goal perspective theory to examine the influence of instructor behaviors on science, technology, engineering, and mathematics (STEM) students’ perceptions of the motivational climate (caring, task, ego) and their adaptive (i.e., effort, enjoyment, performance self-esteem, and social self-esteem) and maladaptive (i.e., shame) experiences in the biology laboratory setting. Students (N = 563; women, 65%; men, 35%) enrolled in biology laboratory courses voluntarily completed a survey during the final week of the semester. Results of two structural equation modeling analyses across gender and racial identities made two important contributions to the STEM higher education literature: 1) when instructors engaged in effective teaching behaviors, students were more likely to perceive a caring/task-involving climate and, in turn, report adaptive motivational responses (i.e., increased effort, enjoyment, self-esteem; decreased shame); and 2) neither gender nor race moderated the measurement of the latent parameters. This research has important pedagogical implications, as teaching assistants could be trained to engage in these effective behaviors to optimize students’ STEM learning experiences

Nowhere minimal CR submanifolds and Levi-flat hypersurfaces

A local uniqueness property of holomorphic functions on real-analytic nowhere minimal CR submanifolds of higher codimension is investigated. A sufficient condition called almost minimality is given and studied. A weaker necessary condition, being contained a possibly singular real-analytic Levi-flat hypersurface is studied and characterized. This question is completely resolved for algebraic submanifolds of codimension 2 and a sufficient condition for noncontainment is given for non algebraic submanifolds. As a consequence, an example of a submanifold of codimension 2, not biholomorphically equivalent to an algebraic one, is given. We also investigate the structure of singularities of Levi-flat hypersurfaces.Comment: 21 pages; conjecture 2.8 was removed in proof; to appear in J. Geom. Ana