PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “COMPUTERS, ANALOG”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources

A hybrid computer system for use in cardiology.

Recent upsurge in the use of physiologic data for medical diagnostic and treatment procedures has prompted the medical profession to use the computer to automate and reduce the time required for data processing. Although the digital computer has traditionally been used to perform these tasks, a hybrid computer (combined analog and digital) has been found to provide many advantages over the digital computer, especially where on-line data processing is concerned. As a result, the Bio-Medical Engineering Center has installed a centrally located hybrid computer system at Ohio State University. One of the applications of this system has been processing cardiac catheterization data. Data is transmitted between the hospital and computer via infrared optics. The data can be analyzed in real time, with the results immediately available to the physician.

Cardiac Catheterization↗

SpikeCell: a deterministic spiking neuron.

We present a model of spiking neuron that emulates the output of the usual static neurons with sigmoidal activation functions. It allows for hardware implementations of standard feedforward networks, trained off-line with any classical learning algorithm (i.e. back-propagation and its variants). The model is validated on hand-written digits recognition, and image classification tasks. A digital architecture is proposed and evaluated. The area needed for implementing the spiking neuron on a chip is 10 times smaller than that for the corresponding static neuron. The accuracy of the network's output increases with time, and reaches that of the emulated static neural network after an adequate integration period. Single errors in the spike trains, or interruption of the relaxation process, due for example to irradiation in harsh environments, are harmless.

Action Potentials↗

Estimation in an island model using simulation.

Estimation for an island model where mutation maintains a k-allele neutral polymorphism at a single locus on each island is considered. The likelihood of an observed sample type configuration is obtained by applying a computational algorithm analogous to Griffiths and Tavaré (Theor. Popul. Biol. 46 (1994), 131-159). This allows the computation of sampling distributions in an island model and investigation of their properties. Given a sample type configuration, the maximum likelihood estimate of the migration parameter is obtained by simulating independently the likelihood at a grid of points and, also, using a surface simulation method. The latter method generates the whole likelihood trajectory in a single application of the simulation program. An estimate of variance of the estimate of the migration parameter is obtained using the likelihood trajectory. A comparison of the maximum likelihood estimates of the gene flow between subpopulations is made with those obtained by using Wright's FST statistic.

Algorithms↗

An interface to input analog signals to a remotely located computer.

Two simple components are described that allow a single microprocessor to monitor several analog instruments. A remote control box with a speaker and a switch allows communication between the operator and the microprocessor. Amplifiers on a printed circuit board ensure that there is no loss in resolution of the input signal. The circuitry allows offset of the input signals relative to the electrical zero, adjustment of the gain of each amplifier and, most importantly, protects the analog to digital converter against destruction by over-range voltages.

Analog-Digital Conversion↗