This paper presents a six-degrees-of-freedom controller for autonomous underwater vehicles. The control algorithm is adaptive in the dynamic parameters that are poorly known and time-varying in the underwater environment. Moreover, the proposed control law adopts quaternions to represent attitude errors, and thus avoids representation singularities that occur when using instead Euler angles des...

Effectiveness of cutting is measured by the ability to achieve a desired rate of material fracture. The work performed by a knife overcomes the material toughness to yield fracture, acts against friction between the material and the blade, and generates shape deformation. This paper studies how to control a robotic arm to achieve a desired time profile of material fracture along a prescribed cu...

The ability to self-right, meaning return to a preferred orientation for mobility, has been identified as a critical robotic capability by soldiers and law enforcement officials [1]. In nature, self-righting can literally mean the difference between life and death. As such, we endeavor to develop a general framework whereby any given robot can autonomously generate a self-righting path whenever...

Recent studies of visual detection show a configuration dependent weak improvement of thresholds with the number of targets, which corresponds to a fourth-root power law. We find this result to be inconsistent with probability summation models, and account for it by a model of 'physiological' integration that is based on excitatory lateral interactions in the visual cortex. The model explains s...

Degradation of piezoelectric properties has been studied in ferroelectric PZT films by means of optical interferometry. The degradation under dc bias and aging of poled films have been observed. The decay of piezoelectric coefficient with time is described by a logarithmic law with aging rates comparable to those of switching polarization. The aging rates are shown to be sensitive to poling con...

It is difficult to ignore the increased visibility of gay men, lesbians and even bisexuals in recent years, whether it be in the media, political fora, the academy, or in different legal contexts. The recent growth in legal scholarship on law, sexuality and sexual orientation is noteworthy as are the sustained efforts by lesbians and gay men to seek redress for social inequalities through litig...

This paper presents the design of a differentiable, kinematic control law that achieves global asymptotic tracking. In addition, we also illustrate how the proposed kinematic controller provides global exponential tracking provided the reference trajectory satisfies a mild persistency of excitation (PE) condition. We also illustrate how the proposed kinematic controller can be slightly modified...

Psychoanalytic and psychiatric perspectives on children who threaten to kill others are reviewed in the context of the need for an interdisciplinary approach to the problem. Converging technologies derived from a psychoanalytically informed social systems model are compared to law enforcement approaches, psychoanalytic understanding of the individual dynamics of the child, and empirical researc...

Metaphors of Computation and Information tended to detract attention from the intrinsic modes of neural system functions, uncontaminated by the observer's role in collection, and interpretation of experimental data. Recognizing the self-referential mode of function, and the propensity for self-organization to critical states requires a fundamentally new orientation, based on Complex System Dyna...

This paper addresses the problem of regulating the dynamic model of a nonholonomic wheeled robot of the unicycle type to a point with a desired orientation. A simple controller is derived that yields global convergence of the trajectories of the closed loop system in the presence of parametric modeling uncertainty. Controller design relies on a non smooth coordinate transformation in the origin...