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While researchers have made notable progress in bio-inspired swimming robot development, a persistent challenge lies in creating propulsive gaits tailored to these robotic systems. The California sea lion achieves its robust swimming abilities through a careful coordination of foreflippers and body segments. In this paper, reinforcement learning (RL) was used to develop a novel sea lion foreflipper gait for a bio-robotic swimmer using a numerically modelled computational representation of the robot. This model integration enabled reinforcement learning to develop desired swimming gaits in the challenging underwater domain. The novel RL gait outperformed the characteristic sea lion foreflipper gait in the simulated underwater domain. When applied to the real-world robot, the RL constructed novel gait performed as well as or better than the characteristic sea lion gait in many factors. This work shows the potential for using complimentary bio-robotic and numerical models with reinforcement learning to enable the development of effective gaits and maneuvers for underwater swimming vehicles. [ABSTRACT FROM AUTHOR]

This study investigated the connection between locus of control (LOC), academic self-efficacy (ASE), and academic performance, and whether these variables are affected by tutoring. Additional variables of interest, including gender, students' Pell Grant status, ethnicity, and class size, were also considered for the research models. The population for this study consisted of students enrolled at a mid-sized public university in northeastern United States who were pre- and posttested as part of a causal-comparative, quasi-experimental research design. Results of this study showed that LOC, tutoring, gender, and an ASE measure identified as self-assurance had positive and significant effects on academic performance as measured by students' total grade point averages. However, tutoring had no effect on LOC but had only a small moderating effect on one component of ASE. It was postulated that assessing incoming students on LOC and ASE measures could aid in identifying students with external LOC and low ASE for possible intervention.

Many agree that educational systems should instill in students the value of lifelong learning (LLL), but few have suggested how to accomplish that or how to measure the effectiveness of those curricular initiatives. We developed a technique intended to strengthen students' beliefs about the value of LLL and piloted use of a recently developed scale to assess changes in commitment to LLL. Using a quasi-experimental procedure, we presented students with faculty members' career biographies describing their personal career paths, including how they learned from their experiences and how they had to adapt and adjust to changing circumstances. To assess beliefs about LLL, students completed Bath and Smith's Propensity for Lifelong Learning (PLLL) scale. We found that students who listened to career biographies had significantly stronger beliefs regarding the value of LLL than the students who were not exposed to the career biographies. We concluded that listening to career biographies strengthened commitment to LLL and that the PLLL scale is a useful outcome measure of this commitment. We discussed limitations and future directions of our method and measurement instrument.

Elements of the homogenization theory are utilized to develop a new micromechanics approach for unit cells of periodic heterogeneous materials based on locally exact elasticity solutions. The interior inclusion problem is exactly solved by using Fourier series representation of the local displacement field. The exterior unit cell periodic boundary-value problem is tackled by using a new variational principle for this class of nonseparable elasticity problems, which leads to exceptionally fast and well-behaved convergence of the Fourier series coefficients. Closed-form expressions for the homogenized moduli of unidirectionally reinforced heterogeneous materials are obtained in terms of Hill's strain concentration matrices valid under arbitrary combined loading, which yield homogenized Hooke's law. Homogenized engineering moduli and local displacement and stress fields of unit cells with offset fibers, which require the use of periodic boundary conditions, are compared to corresponding finite-element results demonstrating excellent correlation. [DOI: 10.1115/1.2913043] Keywords: homogenization, periodicity, variational principle, heterogeneous materials

Several studies are conducted to explain the parametric finite-volume direct averaging micromechanics (FVDAM) theory, which is applied to the uniaxial continuously reinforced periodic materials with elastic phases. The theory, which is extremely efficient in enabling the high-resolution simulation of the local fields, is presented.

Fish coordinate the motion of their fins and body to create the time-varying forces required for swimming and agile maneuvers. To effectively adapt this biological strategy for underwater robots, it is necessary to understand how the location and coordination of interacting fish-like fins affect the production of propulsive forces. In this study, the impact that phase difference, horizontal and vertical spacing, and compliance of paired fins had on net thrust and lateral forces was investigated using two fish-like robotic swimmers and a series of computational fluid dynamic simulations. The results demonstrated that the propulsive forces created by pairs of fins that interact through wake flows are highly dependent on the fins' spacing and compliance. Changes to fin separation of less than one fin length had a dramatic effect on forces, and on the phase difference at which desired forces would occur. These findings have clear implications when designing multi-finned swimming robots. Well-designed, interacting fins can potentially produce several times more propulsive force than a poorly tuned robot with seemingly small differences in the kinematic, geometric, and mechanical properties., (Creative Commons Attribution license.)