System Maintenance:
There may be intermittent impact on performance while updates are in progress. We apologize for the inconvenience.
By Topic

Biomedical Engineering, IEEE Transactions on

Issue 7 • Date July 1986

Filter Results

Displaying Results 1 - 21 of 21
  • IEEE Transactions on Biomedical Engineering - Table of contents

    Publication Year: 1986 , Page(s): c1
    Save to Project icon | Request Permissions | PDF file iconPDF (494 KB)  
    Freely Available from IEEE
  • IEEE Engineering in Medicine and Biology Society

    Publication Year: 1986 , Page(s): c2
    Save to Project icon | Request Permissions | PDF file iconPDF (201 KB)  
    Freely Available from IEEE
  • Quantitative Tissue Characterzation Based on Pulsed-Echo Ultrasound Scans

    Publication Year: 1986 , Page(s): 637 - 643
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4803 KB)  

    This paper describes a novel technique for estimating ultrasonic attenuation coefficients. The technique first employs a histogram analysis to estimate the number of tissues present and then utilizes a maximum likelihood criterion to assign attenuation values, thus producing an image of attenuation. Simulated B-scan data and clinical B-scan data are used to illustrate the method. The results show that images representing an intrinsic tissue parameter can be produced when the basic model is valid. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Na Conductance Kinetics in the Low-Frequency Impedance of Isolated Snail Neurons

    Publication Year: 1986 , Page(s): 644 - 653
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3139 KB)  

    The complex impedance of isolated single neurons of Helix aspersa (snail) was measured at low frequencies (0.25¿100 Hz) with a combination of a suction electrode for applying current and a microelectrode for measuring potential response. A repetitive, Fourier-synthesized signal superposed as a small perturbation (0.2 nA rms) on step current clamps was used in conjunction with Fourier transform techniques to obtain high-resolution impedance data 1 s after a step. The membrane capacitance of an 80 ¿Am diameter cell, measured in the frequency range 2.5¿1000 Hz after suppression of ion conduction, was 1.8 nF and had a constant phase angle of about ¿69°. The resting (¿50 mV) extrapolated zero-frequency resistance, before suppression of conduction in the same cell, of a predominantly Na-conducting membrane was about 5 M¿. Linear ion-conduction parameters were estimated directly by fitting an admittance model, based on the linearized Hodgkin-Huxley equations with a constant-phase-angle capacitance, to the reciprocal of the impedance data. The natural frequencies of Na activation and inactivation processes for small depolarizations (10¿20 mV from rest potential) were determined to be 23¿28 Hz (Tm = 7¿5.7 ms) and 2.5¿1.8 Hz (Th = 64¿88 ms), respectively. These values are more than an order greater than the corresponding relaxation times of Na channels in the squid axon. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Estimation and Verification of a Stochastic Neuron Model

    Publication Year: 1986 , Page(s): 654 - 666
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4370 KB)  

    The treatment of a neuron as an information processor is complicated by the nonlinear, time-varying, and distributed parameter attributes of the classical Hodgkin-Huxley neuron model. In this paper, we fit data from experiments on spontaneously firing snail neurons to a much simpler integrate and fire model featuring random process descriptions of the input current density, threshold, and reset potentials. The method of generalized least squares is used to show that the integrate and fire model explains 99.6 percent of the variation in the data used to describe the population behavior of neurons on the visceral ganglion of the Helix Aspersa snail. Experimental histograms suggest that most of the random variation in the interspike interval is caused by the randomness in the input current density and comparatively little by the random fluctuations in threshold and reset potentials, although the latter are still significant from an information processing viewpoint. Residuals from the regression are used to estimate the range of the input current density random process. The residuals also show that slight, but significant, autocorrelation exists in the input current densities. This suggests that information in addition to the mean input current density is being transmitted in the interspike interval code. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The Inverse Problem in Electrocardiography: A Model Study of the Effects of Geometry and Conductivity Parameters on the Reconstruction of Epicardial Potentials

    Publication Year: 1986 , Page(s): 667 - 676
    Cited by:  Papers (98)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3508 KB)  

    An idealized, analytic model using spherical harmonics was developed to analyze the effects of variations in torso geometry and volume conductivity parameters on the recovery of epicardial potentials from torso potentials. The model was also used to analyze the effects of these variations on individual terms in the orthogonal series expansion. The ability to reconstruct separate, local electrical events on the epicardium was examined under the following simulated situations: 1) all conductivity and geometry parameters were known accurately, 2) the conductivity of individual torso tissue layers was varied, 3) the torso-air boundary was eliminated (the "infinite medium" assumption), 4) the heart position was not accurately known, and 5) the heart size was not accurately known. Variation in conductivity and geometry parameters was found to exert a quantitative and qualitative effect on the amplitude, resolution, and position of the reconstructed epicardial maxima and minima. Significant differences were found in the ability of the inverse procedure to recover epicardial potentials resulting from posterior as opposed to anterior myocardial sources. Important conclusions regarding the narrow allowance for error in heart size and position, and the relative contributions of the torso tissue layer conductivities can provide guidelines for inverse reconstruction of epicardial potentials with a realistic model utilizing the true geometry. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal Respiratory Controller Structures

    Publication Year: 1986 , Page(s): 677 - 680
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1979 KB)  

    It has been assumed that there exists an explicit "exercise stimulus" (i. e., a signal that is correlated to metabolic CO2 production and appropriately drives breathing). Alternatively, the behavior of the respiratory controller during exercise and inspiratory CO2 loading may be dictated by an optimal controller. The purpose of this paper is to examine the behavior of two alternative optimal controller configurations which do not require an explicit "exercise stimulus" for their operation. The first yields a multiplicative behavior between an exercise and airway CO2 load. The second yields an additive behavior between these two loads¿a behavior consistent with that generally observed in man. Thus, an optimal controller structure may be part of the composite structure of respiratory control. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Model Study on the Influence of Structure and Membrane Capacitance on Volume Conduction in Skeletal Muscle Tissue

    Publication Year: 1986 , Page(s): 681 - 689
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3469 KB)  

    The differences between intra-and extracellular conductivity and the capacitive effects of the muscle fiber membranes are responsible for the fact that skeletal muscle tissue in general cannot be considered as a homogeneous volume conductor with frequency independent electrical properties. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quantification of the Alpha EEG Modulation and Its Relation to Cerebral Blood Flow

    Publication Year: 1986 , Page(s): 690 - 696
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2606 KB)  

    A novel method for quantifying the modulation features of the alpha EEG rhythm in terms of global amplitude and frequency modulation indexes has been developed. The method was used to determine the correlation between the modulation of the occipital alpha EEG rhythm and cerebral blood flow. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An X-Band Microwave Life-Detection System

    Publication Year: 1986 , Page(s): 697 - 701
    Cited by:  Papers (86)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3275 KB)  

    An X-band microwave life-detection system has been developed for detecting the heartbeat and breathing of human subjects lying on the ground at a distance of about 30 m or located behind a cinder block wall. The basic principle of the system is to illuminate the subject with a low-intensity microwave beam, and then from the back-scattered microwave signal, extract the heart and breathing signals that modulate it. The circuit description of the system and some experimental results are presented. Potential applications of the system are noted. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Energy Deposition in a Model of Man: Frequency Effects

    Publication Year: 1986 , Page(s): 702 - 711
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2924 KB)  

    A computer-controlled scanning system and implantable, nonperturbing electric field probes were used to measure spatial distributions of the electric field in a full scale homogeneous model of a human body. The measurements were performed at three frequencies (160, 350, and 915 MHz) in the far-field and in the near-field of resonant dipoles. The specific absorption rate (SAR) distributions and the averages for body parts and the whole body are analyzed as functions of frequency. In the far-field, the SAR decreases exponentially in the direction of wave propagation in the torso at all frequencies, and large gradients of the SAR are observed along the body main axis, particularly for the E polarization. At 160 and 350 MHz high local SAR's are produced in the neck. It appears that for plane wave exposures the ratio of the peak SAR to the whole-body average SAR does not exceed 20. In the near-field, large SAR gradients are also produced, and the ratios of the peak spatial SAR to the whole-body average SAR vary from about 30 to 250 depending on the frequency and polarization. It is suggested that for near-field exposures the whole-body average SAR is not a proper dosimetric measure, and the SAR averaged over any 0.1 of the tissue volume is recommended instead. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Implementation of a Microprocessor-Based Tactile Hearing Prosthesis

    Publication Year: 1986 , Page(s): 712 - 716
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2227 KB)  

    A microprocessor-based tactile vocoder is described that offers important advantages over its analog counterpart. Digital implementation provides more flexibility and precision. The system simulates, in real-time, the characteristics of a 16-channel tactile vocoder developed at Queen's University in Kingston, Ont., Canada and is intended for use with a linear array of 16 miniature vibrators. Design considerations of the circuit logic, program structure, and algorithms used to implement the vocoder and the performance characteristics such as the dynamic range and noise of the various algorithms are discussed. The overall system has a noise level less than ¿60 dB re the maximum input and the bandwidth is 7.5 kHz. The system will first be used in the laboratory and in the classroom with two microphones and two tactile displays. Future plans call for the design to be adapted to lower power devices, when they become available, to achieve a single-display, wearable version that can be evaluated under natural conditions of acoustic signal and noise. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive Filter Processing in Microwave Remote Heart Monitors

    Publication Year: 1986 , Page(s): 717 - 722
    Cited by:  Papers (4)  |  Patents (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (966 KB)  

    This commmunication describes some current applications tions of adaptive filtering to the processing of microwave Doppler signals for heart rate monitoring. The problem has been approached in the past using signal processing techniques such as peak detection or autocorrelation. These methods either require large amounts of data or tend to be unreliable. This communication utilizes some recent techniques used in speech processing and applies them to heartbeat detection, thus allowing on-line processing of sampled microwave heart signals. The presentation includes a model for the signal, brief discussions of the algorithms evaluated, and qualitative analysis of performance compared to EKG measurements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Computer-Assisted Continuous Infusion of the Intravenous Analgesic Fentanyl During General Anesthesia-An Interactive System"

    Publication Year: 1986 , Page(s): 722 - 723
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (421 KB)  

    This communication shows an algorithm used in the drug infusion system discussed in a recent paper1 to be incorrect. The error is corrected, and a new algorithm is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "A New CT-Aided Stereotactic Neurosurgery Technique"

    Publication Year: 1986 , Page(s): 723 - 724
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    The method given for finding the position of a target in three-dimensional space from a CT image is incorrect. The solution is based on representation of the target vector as a linear combination of two coplanar nonparallel vectors. This results in a single linear equation with two unknowns. An alternative formulation is offered, solved, and the existence and uniqueness of the solution is proved. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Authors' reply2

    Publication Year: 1986 , Page(s): 724
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (191 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Separation of a Nonstationary Component from the EEG by a Nonlinear Digital Filter

    Publication Year: 1986 , Page(s): 724 - 726
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    A new nonlinear digital filter which separates nonstationary waves such as spikes from stationary background waves of the EEG is proposed. This filter is composed of a prediction filter and a simple nonlinear function. Some examples showing the separation of spikes from EEG data of epileptic patients are given. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Announcement and Call for Papers 6th International Meeting on Clinical Laboratory Organization and Management

    Publication Year: 1986 , Page(s): 727
    Save to Project icon | Request Permissions | PDF file iconPDF (50 KB)  
    Freely Available from IEEE
  • Now is the best time to join our Society

    Publication Year: 1986 , Page(s): 728
    Save to Project icon | Request Permissions | PDF file iconPDF (169 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Biomedical Engineering Statement of Editorial Policy

    Publication Year: 1986 , Page(s): 728-a
    Save to Project icon | Request Permissions | PDF file iconPDF (204 KB)  
    Freely Available from IEEE
  • Institutional listings

    Publication Year: 1986 , Page(s): 728b
    Save to Project icon | Request Permissions | PDF file iconPDF (52 KB)  
    Freely Available from IEEE

Aims & Scope

IEEE Transactions on Biomedical Engineering contains basic and applied papers dealing with biomedical engineering. Papers range from engineering development in methods and techniques with biomedical applications to experimental and clinical investigations with engineering contributions.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Bin He
Department of Biomedical Engineering