Search results for "Time delays"

Knowledge of alpha-1 deficiency and primary ciliary dyskinesia by medical students and health professionals

2016

Background: Under-diagnosis and delayed diagnosis are common features in rare diseases, which have negative effects on the patients9 prognosis. A possible explanation could be lack of awareness and education of the health professionals involved in the managements of these patients. Alpha-1-antitrypsin deficiency (AATD) and primary ciliary dyskinesia (DCP) are under-diagnosed rare diseases showing a median diagnosis delay of five to ten years. Methods: A survey was undertaken in paediatricians (general, paediatric pulmonologists and paediatric gastroenterologist) and medical school students to assess their knowledge on AATD and PCD. Results: A total of 624 surveys on AATD and 457 on PCD were…

Determination of Synchronization of Electrical Activity in the Heart by Shannon Entropy Measure

2005

In this paper we propose a new index of synchronization for the study of heart’s electrical activity during atrial fibrillation (AF). The index relies on the measure of the time delays between correspondent activations in two atrial electrograms and on the characterization of their dispersion by a measure of Shannon Entropy. The algorithm was validated on simulated signals mimicking different degree of synchronization. Results showed the index was able to discriminate among different levels of organization, provided that it works on series of at least 50 activations (time resolution of almost 10 sec during AF). Moreover, we applied the algorithm to real bipolar electrograms, obtained from a…

Quantification of synchronization during atrial fibrillation by Shannon entropy: Validation in patients and computer model of atrial arrhythmias

2005

Atrial fibrillation (AF), a cardiac arrhythmia classically described as completely desynchronized, is now known to show a certain amount of synchronized electrical activity. In the present work a new method for quantifying the level of synchronization of the electrical activity recorded in pairs of atrial sites during atrial fibrillation is presented. A synchronization index (Sy) was defined by quantifying the degree of complexity of the distribution of the time delays between sites by Shannon entropy estimation. The capability of Sy to discriminate different AF types in patients was assessed on a database of 60 pairs of endocardial recordings from a multipolar basket catheter. The analysis…

Stability analysis of logistics networks with time-delays

2012

Logistics network represents a complex system where different elements that are logistic locations interact with each other. This interaction contains delays caused by time needed for delivery of the material. In this paper, we study local input-to-state stability of such logistics networks. Their behaviour is described by a functional differential equation with a constant time-delay. An appropriate Lyapunov–Razumikhin function and the small gain condition are utilized to establish some conditions for stability analysis of the network under consideration. Our stability conditions for the logistics network are based on the information about the interconnection properties between logistic loc…

Application of the LISS Lyapunov-Krasovskii small-gain theorem to autonomously controlled production networks with time-delays

2010

Accepted version of a paper published by IEEE. (c) 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works Published version: http://dx.doi.org/10.1109/SYSTOL.2010.5676085 In this paper we consider general autonomously controlled production networks. A production network consists of geographically distributed plants, which are connected by transport routes such that transportation times (time-delays) …

Adaptive H ∞ synchronization of master-slave systems with mixed time-varying delays and nonlinear perturbations: An LMI approach

2011

Published version of an article in the journal: International Journal of Automation and Computing. Also available from the publisher on SpringerLink: http://dx.doi.org/10.1007/s11633-011-0595-z This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed time delays. Using an appropriate Lyapunov-Krasovskii functional, some delay-dependent sufficient conditions and an adaptation law including the master-slave parameters are established for designing a delayed synchronization law in terms of linear matrix inequalities(LMIs). The time-varying…

Time delays in starting thrombolytic therapy

1998

Exponential stability analysis of Markovian jump nonlinear systems with mixed time delays and partially known transition probabilities

2013

In this paper, the problem of exponential stability is studied for a class of Markovian jump neutral nonlinear systems with mixed neutral and discrete time delays. By Lyapunov-Krasovskii function approach, a novel mean-square exponential stability criterion is derived for the situation that the system's transition rates are partially or completely accessible. Finally, some numerical examples are provided to illustrate the effectiveness of the proposed methods.

Temporal trends in prehospital management of ST-segment elevation myocardial infarction from 2002 to 2010 in Cote d’Or: Data from the RICO registry (…

2012

Summary Background Myocardial infarction with ST-segment elevation (STEMI) is a medical emergency requiring specific management, with the main aim of achieving reperfusion as quickly as possible. Guidelines from medical societies have defined optimal management, with proven efficacy on morbi-mortality. Aims Our study aimed to evaluate trends in practices between 2002 and 2010 in the emergency management of STEMI in a single French department, namely Cote d’Or. Methods All patients admitted with a first STEMI to one of the six participating coronary care units (private or public) in Cote d’Or since January 2001 were included in a prospective registry (obseRvatoire des Infarctus de Cote d’Or …

Size of the accretion disk in the gravitationally lensed quasar SDSS J1004+4112 from the statistics of microlensing magnifications

2016

We present eight monitoring seasons of the four brightest images of the gravitational lens SDSS J1004+4112 observed between December 2003 and October 2010. Using measured time delays for the images A, B and C and the model predicted time delay for image D we have removed the intrinsic quasar variability, finding microlensing events of about 0.5 and 0.7 mag of amplitude in the images C and D. From the statistics of microlensing amplitudes in images A, C, and D, we have inferred the half-light radius (at {\lambda} rest = 2407 {\AA}) for the accretion disk using two different methods, $R_{1/2}=8.7^{+18.5}_{-5.5} \sqrt{M/0.3 M_\odot}$ (histograms product) and $R_{1/2} = 4.2^{+3.2}_{-2.2} \sqrt{…