Search results for "Measurement"
showing 10 items of 2918 documents
State Observer with Round-Robin Aperiodic Sampled Measurements with Jitter
2021
International audience; A sampled-data observer is proposed for linear continuous-time systems whose outputs are sequentially sampled via non-uniform sampling intervals repeating a prescribed Round-Robin sequence. With constant sampling intervals (jitter-free case) we provide constructive necessary and sufficient conditions for the design of an asymptotic continuous-discrete observer whose estimation error is input-to-state stable (ISS) from process disturbances and measurement noise. We use a time-varying gain depending on the elapsed time since the last measurement. With non-constant sampling intervals (jitter-tolerant case), our design conditions are only sufficient. A suspension system …
An algebraic approach for human posture estimation in the sagittal plane using accelerometer noisy signal
2012
International audience; Our aim is to develop an algebraic approach to estimate human posture in the sagittal plane using Inertial Measurement Unit (IMU) providing accelerations and angular velocities. To do it so, we address the issue of the estimation of the amplitude, frequency and phase of a biased and noisy sum of three sinusoidal waveform signals on a moving time horizon. Since the length of the time window is small, the estimation must be done within a fraction of the signal's period. The problem is solved via algebraic techniques (see [38] for the theoretical part concerning this problem). The efficiency of our approach is illustrated by computer simulations.
A time-varying observer for linear systems with asynchronous discrete-time measurements
2017
International audience; In this paper we propose a time-varying observer for a linear continuous-time plant with asynchronous discrete-time measurements. The proposed observer is contextualized in the hybrid systems framework providing an elegant setting for the proposed solution. In particular some theoretical tools are provided, in terms of LMIs, certifying asymptotic stability of a certain compact set where the estimation error is zero. Moreover the case of asynchronous measurements is considered, i.e. when the measurements are not provided in well defined time instants, but they occur at an arbitrary time in a certain time interval. A design procedure based on the numerical solution of …
Internal Structure and Measurement Invariance of the Dutch Eating Behavior Questionnaire (DEBQ) in a (Nearly) Representative Dutch Community Sample
2016
The Dutch Eating Behavior Questionnaire is a widely used instrument for assessment of emotional, external and restrained eating. The aim of the present study is to (i) analyse its internal structure using exploratory structural equation modelling; (ii) to assess its measurement invariance with respect to sex, BMI, age and level of education; and (iii) to evaluate the relations of the factors with these variables. Except that women were slightly over-represented, the sample (n = 2173) closely followed the sociodemographic characteristics of the overall Dutch population. The three theoretical factors that emerged from the analysis were in close correspondence with the three scales for emotion…
Effect of laser treatment on postural control parameters in patients with chronic nonspecific low back pain: a randomized placebo-controlled trial
2019
The management of nonspecific lumbar pain (NSLP) using laser irradiation remains controversial. A systematic review of recently published studies indicates that the effects of laser therapy are commonly assessed using only imperfect methods in terms of measurement error. The main objective of this study was to assess static postural stability using an objective tool in patients with chronic NSLP after laser irradiation at different doses and wavelengths. In total, 68 patients were included in the laser sessions and were randomly assigned into four groups: high-intensity laser therapy at 1064 nm and 60 J/cm2 for 10 min (HILT), sham (HILT placebo), low-level laser therapy at 785 nm and 8 J/cm…
Different Brain Circuitries Mediating Controllable and Uncontrollable Pain.
2015
Uncontrollable, compared with controllable, painful stimulation can lead to increased pain perception and activation in pain-processing brain regions, but it is currently unknown which brain areas mediate this effect. When pain is controllable, the lateral prefrontal cortex (PFC) seems to inhibit pain processing, although it is unclear how this is achieved. Using fMRI in healthy volunteers, we examined brain activation during controllable and uncontrollable stimulation to answer these questions. In the controllable task, participants self-adjusted temperatures applied to their hand of pain or warm intensities to provoke a constant sensation. In the uncontrollable task, the temperature time …
The utility of measuring tear film break-up time for prescribing contact lenses.
2017
Abstract Purpose To evaluate the clinical value of non-invasive keratograph tear film breakup time (NIKBUT) in the assessment of pre-corneal and pre-lens tear film quality for prescribing contact lenses (CLs). Methods Forty-six subjects aged 25.5 ± 4.3 (mean ± standard deviation) years were recruited. Visual acuity (VA), anterior eye health checks and NIKBUT were evaluated. On the following day, subjects were fitted with a daily Silicon Hydrogel (SiHy) CL in one eye and a Hydrogel (Hy) CL in the other. After four hours one material for both eyes was chosen based on a qualitative analysis which included VA, CL fitting and comfort. Information about the first and the mean NIKBUT was then cont…
Does the educational level of women influence hand grip and pinch strength in carpal tunnel syndrome?
2020
Abstract Background Grip and pinch strength are relevant functional variables for various activities of daily life and are related to the quality of life of patients with carpal tunnel syndrome (CTS). Objective The main aim was to analyze the relationship between grip and pinch strength and the educational level in women with CTS. Study design Cross-sectional study. Methods Thirty-one female patients with CTS awaiting surgery were assigned to the low education group if they only had primary education level (completed or not) and the high education group for those having higher education level. The assessments included: grip strength, pinch strength, Visual Analogue Scale, Quick DASH Questio…
Progranulin overexpression in sensory neurons attenuates neuropathic pain in mice: Role of autophagy
2016
Peripheral or central nerve injury is a frequent cause of chronic pain and the mechanisms are not fully understood. Using newly generated transgenic mice we show that progranulin overexpression in sensory neurons attenuates neuropathic pain after sciatic nerve injury and accelerates nerve healing. A yeast-2-hybrid screen revealed putative interactions of progranulin with autophagy-related proteins, ATG12 and ATG4b. This was supported by colocalization and proteomic studies showing regulations of ATG13 and ATG4b and other members of the autophagy network, lysosomal proteins and proteins involved in endocytosis. The association of progranulin with the autophagic pathway was functionally confi…
A clinical review on megalencephaly: A large brain as a possible sign of cerebral impairment
2017
Megalencephaly and macrocephaly present with a head circumference measurement 2 standard deviations above the age-related mean. However, even if pathologic events resulting in both megalencephaly and macrocephaly may coexist, a distinction between these two entities is appropriate, as they represent clinical expression of different disorders with a different approach in clinical work-up, overall prognosis, and treatment. Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases or as a consequence of postnatal abnormal events. The disorders associate…