Search results for "Control systems"

Contrast sensitivity of the visual system in speckle imagery

1994

The contrast sensitivity function (CSF) of the whole visual system is determined with the use of coherent diffuse illumination. This function provides supplementary data about the effect of speckle on the ability of the visual system to perceive the spatial information contained in an image. The results show that speckle not only prevents perception of the finest details (highest frequencies) but also reduces the visibility of lower frequencies (especially where contrast is low). The difference between the CSF's determined with and without speckle is quantitatively very important. And the ratio between the two CSF's is a measure of the retinal ability to perceive contrast in the presence of…

Non-celiac wheat sensitivity is a more appropriate label than non-celiac gluten sensitivity.

2013

Repeatability and sensitivity of passive mechanical stiffness measurements in the triceps surae muscle‐tendon complex

2021

Measurements of muscle-tendon unit passive mechanical properties are often used to illustrate acute and chronic responses to a training stimulus. The purpose of this study was to quantify the inter-session repeatability of triceps surae passive stiffness measurements in athletic and non-athletic populations, with the view to discussing its usefulness both as a muscle-tendon profiling tool and a control measure for studies with multiple data collection sessions. The study also aimed to observe the effects of quiet standing on passive stiffness parameters. Twenty-nine men (10 cyclists, nine triathletes, 10 controls) visited the laboratory on three separate occasions, where passive stiffness t…

Dynamics of price sensitivity among mobile service customers

2005

PurposePrice sensitivity is one of the key factors affecting to companies pricing choices. Yet in mobile services sector business practitioners are facing problems in pricing decisions as they are short of knowledge on their customers’ price sensitivity levels and dynamics. Therefore this study aims to focus on this unexplored field in order to provide more accurate tools for mobile service providers to price their services more effectively.Design/methodology/approachThis study is conducted on Finnish mobile services markets. The focus is on examining how customers’ price sensitivity differs between different customer segments and which factors affect to the price sensitivity levels. The sa…

Bayesian methods in cost-effectiveness studies: objectivity, computation and other relevant aspects.

2009

In a probabilistic sensitivity analysis (PSA) of a cost-effectiveness (CE) study, the unknown parameters are considered as random variables. A crucial question is what probabilistic distribution is suitable for synthesizing the available information (mainly data from clinical trials) about these parameters. In this context, the important role of Bayesian methodology has been recognized, where the parameters are of a random nature. We explore, in the context of CE analyses, how formal objective Bayesian methods can be implemented. We fully illustrate the methodology using two CE problems that frequently appear in the CE literature. The results are compared with those obtained with other popu…

The Determination of Mass: 3.5 Vacuum Weighing

2005

Passive alignment stability and auto-alignment of multipass amplifiers based on Fourier transforms.

2019

The stability properties of Fourier-based multipass amplifier to misalignments (tilts) of its optical components has been investigated. For this purpose, a method to quantify the sensitivity to tilts based on the amplifier small signal gain has been elaborated and compared with measurements. To improve on the tilt stability by more than an order of magnitude a simple auto-alignment system has been proposed and tested. This study, combined with other investigations devoted to the stability of the output beam to variations of aperture and thermal lens effects of the active medium, qualifies the Fourier-based amplifier for the high-energy and the high-power sector.

Diffusion and sensitivity characteristics of a chemically cross-linked PVA-Fricke gel dosimeter

2016

Optically Enhanced Electric Field Sensing Using Nitrogen-Vacancy Ensembles

2021

Nitrogen-vacancy (NV) centers in diamond have shown promise as inherently localized electric-field sensors, capable of detecting individual charges with nanometer resolution. Working with NV ensembles, we demonstrate that a detailed understanding of the internal electric field environment enables enhanced sensitivity in the detection of external electric fields. We follow this logic along two complementary paths. First, using excitation tuned near the NV's zero-phonon line, we perform optically detected magnetic resonance (ODMR) spectroscopy at cryogenic temperatures in order to precisely measure the NV center's excited-state susceptibility to electric fields. In doing so, we demonstrate th…

Sensitivity Analysis and Effect of Simulation parameters of CPFD Simulation in Fluidized Beds

2018

Fluidized bed technology is broadly applied in industry due to its distinct advantages. CFD simulation of fluidized beds is still challenging compared to single-phase systems and needs extensive validation. Multiphase particle-in-cell is a recently developed lagrangian modeling technique and this work is devoted to analyze the sensitivity of grid size, time step, and model parameters, which are the essences of accurate results. Barracuda VR 17.1.0 commercial CFD package was used in this study. 500µm sand particles and air was used as the bed material and fluidization gas respectively. Five different grids, having 27378, 22176, 16819, 9000 and 6656 computational cells were analysed, where fi…