Sample Entropy of Speed Power Spectrum as a Measure of Laparoscopic Surgical Instrument Trajectory Smoothness.

In this study the complexity of the speed power spectrum is assessed as a metric for measuring trajectory smoothness. There are a variety of published methods for analyzing trajectory smoothness but many lack validity. This preliminary study took an information theoretic approach to assess trajectory smoothness by applying the sample entropy measure to the speed power spectrum of simulated and experimental trajectories.

Objective Assessment of the Early Stages of the Learning Curve for the Senhance Surgical Robotic System.

Objective: The purpose of this research is to study the early stages of the Senhance learning curve to report how force feedback impacts learning rate. This serves as an exploratory investigation into assumptions that fellows and faculty will adjust faster to the Senhance in comparison with residents, and that force feedback will not hinder skill acquisition.

Design: In this study, participants completed the peg transfer and precision cutting task from the Fundamentals of Laparoscopic Surgery (FLS) manual skills assessment five times each using the Senhance while instrument motion was tracked.

Automating neurosurgical tumor resection surgery: Volumetric laser ablation of cadaveric porcine brain with integrated surface mapping.

Objective: Current surgical instruments for soft tissue resection including neurosurgical procedures rely on the accuracy and precision of the human operator and are fundamentally constrained by the human hand. Automated surgical action with the integration of intraoperative data sources can enable highly accurate and fast tissue manipulation using laser ablation. This study presents the first experiments with a prototype designed for automated tumor resection via laser ablation.

Passive band-gap reconfiguration born from bifurcation asymmetry.

Current periodic structures are constrained to have fixed energy transmission behavior unless active control or component replacement is used to alter their wave propagation characteristics. The introduction of nonlinearity to generate multiple stable equilibria is an alternative strategy for realizing distinct energy propagation behaviors. We investigate the creation of a reconfigurable band-gap system by implementing passive switching between multiple stable states of equilibrium, to alter the level of energy attenuation in response to environmental stimuli.

Spectral element method and the delayed feedback control of chaos.

A spectral element approach is introduced to determine the Floquet exponents (FEs) of unstable periodic orbits (UPOs) stabilized by extended delayed feedback control (EDFC). The spectral approach does not require solving time-dependent eigenproblems that existing methods require. Instead, the spectral approach determines the stability of the delay differential equations of the system by numerical approximation.