Search results for " Computer"
showing 10 items of 6910 documents
A New Systematic Classification of Peripheral Anatomy of the Right Hepatic Duct: Experience From Adult Live Liver Donor Transplantation
2008
Abstract Objective The peripheral intrahepatic biliary anatomy, especially at the sectorial level on the right side, has not been adequately described. The purpose of our study was to systematically describe this complex anatomy in clinically applicable fashion. Patients and Methods We analyzed three-dimensional computed tomography (CT) imaging reconstructions of 139 potential living liver donors evaluated at our institution between January 2003 and June 2007. Results Eighty-nine (64%) donors had a normal right bile duct sectorial anatomy. In the other 50/139 (36%) cases, we observed abnormal sectorial branching patterns, with 45/50 abnormalities as trifurcations, whereas the remaining ones…
The use of computer-assisted video image analysis for the quantification of CD8+ T lymphocytes producing tumor necrosis factor alpha spots in respons…
1997
Enzyme-linked immunospot (ELISPOT) analysis is a sensitive technique for the detection and quantification of single T lymphocytes forming cytokine spots after antigen contact in vitro. Herein computer-assisted video image analysis (CVIA) was applied to automatically determine the number and size of tumor necrosis factor alpha (TNF-alpha) spots formed by single blood-derived CD8+ T cells after contact with peptide-loaded target cells. With CVIA and TNF-alpha ELISPOT analysis we quantified CD8+ T cells responsive to HLA-A2.1-binding tyrosinase and influenza matrix peptides in healthy donors. We followed the course of the virus-specific T cell response in two HLA-A2-positive patients with reac…
Multicenter validation of the magnetic resonance t2* technique for segmental and global quantification of myocardial iron
2009
Purpose To assess the transferability of the magnetic resonance imaging (MRI) multislice multiecho T2* technique for global and segmental measurement of iron overload in thalassemia patients. Materials and Methods Multiecho T2* sequences were installed on six MRI scanners. Five healthy subjects (n = 30) were scanned at each site; five thalassemia major (TM) patients were scanned at the reference site and were rescanned locally (n = 25) within 1 month. T2* images were analyzed using previously validated software. Results T2* values of healthy subjects showed intersite homogeneity. On TM patients, for global heart T2* values the correlation coefficient was 0.97, coefficients of variation (CoV…
Determinants of homonym and synonym rates of record linkage in disease registration.
1996
AbstractReliable record linkage is an essential component of the quality of population-based disease registration. Quality assessment of disease registries should, therefore, include quantitative approaches to describe the extent of record-linkage errors. The homonym and synonym rates have been proposed for this purpose. The homonym rate quantifies the proportion of distinct patients excluded from registration due to erroneous linkage with other patients. The synonym rate quantifies the proportion of unrecognized duplicate notifications on patients already registered in the registry. This paper provides an algebraic assessment of the determinants of both rates. It is shown how the homonym a…
Quantifying stenosis in renal arteriograms: a fuzzy syntactic analysis.
1999
AbstractThe introduction of fuzzy logic improves a system for the automatic quantification of renal artery lesions seen in digital subtraction angiograms. A two-step approach has been followed. An earlier system based on non-fuzzy syntactic analysis provided a clear symbolic description of the stenotic lesions. Although this system worked correctly, it did not take into account the variability and uncertainty inherent to image processing and to knowledge on the reference diameter. This system has been improved by the introduction of fuzzy logic in the representation of the reference diameter. It provides a description of the stenosis in terms of fuzzy quantities. To illustrate the benefits …
A robust aerial image registration method using Gaussian mixture models
2014
Aerial image registration is one of the bases in many aerospace applications, such as aerial reconnaissance and aerial mapping. In this paper, we propose a novel aerial image registration algorithm which is based on Gaussian mixture models. First of all, considering the characters of the aerial images, the work uses a shape feature detector which computes the boundaries of regions with nearly the same gray-value to extract invariant feature. Then, a Gaussian mixture models (GMM) based image registration model is built and solved to estimate the transformation matrix between two aerial images. Furthermore, the proposed method is applied on real aerial images, and the results demonstrate the …
The design of an agent based model of human activities and communications in cardiac resuscitation
2015
International audience; Cardio-pulmonary arrest is a common emergency situation causing over 400,000 deaths per year, more than a 1000 per day, in the USA alone. The goal of this work is to develop an agent based computer simulator that will allow trainers to experiment with different communication protocols, such as those found in air traffic control. This paper describes the first step in designing the simulator development. The design is based on an analysis of communications during real life training simulations using the FIPA standard categories.
ABM of Civil Violence: ODD Description
2017
This chapter contains a description of the proposed agent-based model, using the well-known “Overview, Design Concepts and Details” protocol. The model was implemented in NetLogo and is based on the same two types of agents—citizens and law-enforcement—as in Epstein’s model, but “citizen” agents have one subtype (“activist”) used for implementing network influence effects. The salient aspects of the model description are centered on the submodels for the risk perception, the expression of hardship in terms of value-sensitive relative deprivation, endogenous legitimacy feedback and network influence effects, which provide extensions to Epstein’s model. The model includes two networks called …
Semantically enriched informed environment for multi-agent simulation : application to simulation in 3D virtual environment
2014
This thesis focuses on multi-agent simulation applied to the simulation of individuals in virtual 3D buildings. To do this, our work suggests to capitalize on the experience gained in the field of semantic web ontologies and inference engines to facilitate the design and development of intelligent behavior for agents operating in virtual worlds. The goal is to provide to agents a generic approach to managing their representation of the world and reason about this representation. For this, the central problem is based on the definition of a decidable ontology modeling all of the knowledge contained in the virtual 3D environment to enrich semantically the environment of a multi-agent simulati…
Balance control in aging: improvements in anticipatory postural adjustments and updating of internal models
2015
International audience; Postural stability of older subjects can be estimated during orthostatic equilibrium. However, dynamic equilibrium is also important to investigate risks of fall. It implies different interpretations of measures given by force plates. Same dependant variables (e.g. center of pressure displacement) cannot be interpreted the same ways depending of the type of equilibrium that is investigated. In particular, sways increases during dynamic equilibrium and before movement execution may reflect an improvement of feedforward control.