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The stability of haptic simulation systems has been studied for a safer interaction with virtual environments. In this work, the passivity, uncoupled stability, and fidelity of such systems are analyzed when a viscoelastic virtual environment is implemented using a general discretization method that can also represent methods such as backward difference, Tustin, and zero-order-hold. Dimensionless parametrization and rational delay are considered for device independent analysis. Aiming at expanding the virtual environment dynamic range, equations to find optimum damping values for maximize stiffness are derived and it is shown that by tuning the parameters for a customized discretization method, the virtual environment dynamic range will supersede the ranges offered by methods such as backward difference, Tustin and zero-order-hold. It is also shown that minimum time delay is required for stable Tustin implementation and that specific delay ranges must be avoided. The proposed discretization method is numerically and experimentally evaluated.
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http://dx.doi.org/10.1109/TOH.2023.3268861 | DOI Listing |
Acta Biotheor
September 2025
AMAP - INRAE, CIRAD, CNRS, IRD, Université Montpellier, Montpellier, France.
Recent studies in biology and ecology show striking convergences with process philosophy (PP). Biologists today are debating the real nature of evolution and of life itself, which is increasingly considered as a set of interrelated processes rather than a set of tangible species and material lineages. This perspective of focusing on changes can also be found with ecologists and environmental ethicists, whose studies feed into as well as draw on PP principles.
View Article and Find Full Text PDFJ Acoust Soc Am
September 2025
Key Laboratory of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093, China.
Rectangular horns are widely used in professional audio applications, but designing horns with desired radiation efficiency and directivity is time-consuming and often relies on empirical methods. A multimodal-based optimization approach is proposed in this study and can simultaneously improve the radiation efficiency and directivity control of rectangular horns over a wide frequency range. Based on acoustical properties accurately simulated by a discrete model, the terms in the objective function are constructed to measure radiation efficiency, penalize jagged shapes, and improve directivity control.
View Article and Find Full Text PDFJB JS Open Access
September 2025
Department of Orthopaedic Surgery, Mass General Brigham, Harvard Medical School, Boston, Massachusetts.
Background: It is unclear whether the current North Atlantic Treaty Organization (NATO) trauma system will be effective in the setting of Large-Scale Combat Operations (LSCO). We sought to model the efficacy of the NATO trauma system in the setting of LSCO. We also intended to model novel scenarios that could better adapt the current system to LSCO.
View Article and Find Full Text PDFFront Neurol
August 2025
Otolaryngology-Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States.
Introduction: External continuous perturbations using a motion platform have been developed by employing either sum-of-sines (SoS) or a pseudorandom ternary sequence (PRTS) of numbers to quantify body sway evoked in the medial-lateral (ML) or anterior-posterior (AP) directions, which ultimately helps understand the human postural control system. These stimuli have been provided via pitch tilts of the motion platform for evaluations of AP balance responses or roll tilts for ML balance responses. However, little is known about whether a healthy postural control system responds to 2-dimensional (2D) perturbations similarly when the perturbation stimuli are provided in semicircular canal coordinates (i.
View Article and Find Full Text PDFHRB Open Res
April 2025
General Practice, Royal College of Surgeons in Ireland, Dublin, Leinster, Ireland.
Background: Lung cancer (LC) is the leading cause of cancer death in Ireland, yet no national screening programme exists. While low-dose computed tomography (LDCT) screening reduces lung cancer mortality by approximately 20% in high-risk populations, its cost-effectiveness in Ireland remains uncertain. Evidence on the economic burden of lung cancer care and the feasibility of screening is needed to support policy decisions.
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