Proceedings of the 1991 IEEE Seventeenth Annual Northeast Bioengineering Conference

4-5 April 1991

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Displaying Results 1 - 25 of 112
  • An artificial neural network for studying binaural sound localization

    Publication Year: 1991, Page(s):1 - 2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (194 KB)

    A three-layer neural network is used to solve the problem of extracting relative azimuth and elevation positional information from signals detected by two directional receivers that are spatially separate. This is analogous to the ability of owls to localize the position of sound sources based solely on the properties of the signals reaching the two ears. Although the network implemented does not ... View full abstract»

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  • Analyzing biological signals with CMAC, a neural network

    Publication Year: 1991, Page(s):3 - 4
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (153 KB)

    The neural network CMAC (Cerebellar Mode Arithmetic Computer) is discussed. CMAC is used as the main control device in an effort to develop a brain-computer link. If a person intends to move his/her eyes up, down, left, or right, it is hypothesized that a distinct electroencephalogram pattern exists for each intended direction. The CMAC could then be trained to recognize these four directional pat... View full abstract»

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  • Modeling amplitude-modulated (AM) tone encoding behavior of cochlear nucleus neurons

    Publication Year: 1991, Page(s):5 - 6
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    An attempt was made to understand the mechanisms underlying the response of the cochlear nucleus (CN) neurons, specifically the choppers, to the AM tone. The AM tone excitation via the auditory nerve fibers was modeled as a combination of DC, AC, and a zero-mean Gaussian noise current at the soma of the model neuron. The DC represents the high frequency carrier beyond the neuron's phase-locking li... View full abstract»

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  • Neural network classification of EEG data generated through use of the audio oddball paradigm

    Publication Year: 1991, Page(s):7 - 8
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    Single trial electrical brain evoked potentials were recorded using two different audio stimuli with unequal probabilities of occurrence. A modified self-organizing Kohonen neural network was used to organize the responses. The output of the network formed a topological map of the various component responses which included both changes in the evoked potential waveforms and the performance reaction... View full abstract»

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  • Unsupervised learning in constrained linear networks

    Publication Year: 1991, Page(s):9 - 10
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (173 KB)

    Constrained linear architectures which learn in unsupervised mode according to Hebb's rule to minimize the output energy are analyzed. Under which conditions such networks act as decorrelating (square-root) filters is investigated. An algorithm is proposed which is almost optimum since the inputs of each filter (which are also the outputs of the net) become more and more decorrelated as the algori... View full abstract»

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  • Harmonic analysis of binaural interaction potentials

    Publication Year: 1991, Page(s):11 - 12
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    A general response model is proposed which suggests that low frequency tones in masking noise may be a useful test stimulus to differentiate between binaural interaction (BI) responses from various superior olivary complex cell types. The model consists of an element acting on input signals from the cochlear nucleus (CN). For each element the output consists of spontaneous rate (SR), weights A and... View full abstract»

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  • Learning binaural sound localization through a neural network

    Publication Year: 1991, Page(s):13 - 14
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (157 KB)

    A neural network system is implemented that uses binaural time/intensity cues for determining azimuth/elevation of a sound source. The system is designed to approximately mimic the sound localization behavior of the owl. The network is trained in a supervised learning mode. The errors between the estimated position (from the neural net) and the actual position (from an ideal optical sensor) are us... View full abstract»

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  • Establishing constitutive relationships for soft biological tissues

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (58 KB)

    Summary form only given. An algorithm is presented by which stress-strain relationships, or constitutive equations, for various soft tissues may be developed, and some of the pitfalls affecting the process are discussed. These concepts are illustrated using the lung as an example. Four elements are required for analysis of the deformation of a body: (1) the geometry of the body in question, (2) a ... View full abstract»

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  • Evolution of myocardial constitutive relations

    Publication Year: 1991, Page(s):18 - 19
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (183 KB)

    Major developments in the assessment of myocardial constitutive relations are outlined as they illustrate the progressive sophistication in experimental soft tissue mechanics. An evolution in the determination of constitutive relations is described that includes a variety of experimental techniques and different approaches to data analysis. Three approaches to the determination of a specific funct... View full abstract»

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  • A model of connective tissue micromechanics

    Publication Year: 1991, Page(s):20 - 21
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (143 KB)

    Unifying concepts at the level of microstructure are developed to account for macroscopic connective tissue elasticity, energy dissipation, and its time-varying response to mechanical loads. A fiber-fiber kinetics model based on the assumption that both rate-dependent and rate-independent dissipative stresses arise in the interaction among fibers in the connective tissue matrix is established. The... View full abstract»

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  • Pressure assisted gallbladder evaluation system for determination of the biomechanical characteristics of the gallbladder

    Publication Year: 1991, Page(s):22 - 23
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    The Pressure Assisted Gallbladder Evaluation (PAGE) system was developed for accurate, automatic, and safe measurement of the leakage pressure, compliance, volume, work of infusion, and cystic duct resistance. The PAGE system comprises a pressure-feedback-controlled constant-rate infusion pump and an intra-gallbladder pressure monitoring and recording setup. The system appears to fulfil the desire... View full abstract»

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  • A biomechanical study of a cervical spine stabilization device

    Publication Year: 1991, Page(s):24 - 25
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (194 KB)

    The biomechanical properties of surgically destabilized cervical spine motion segments are evaluated. The segments were fixed with spinal fixation plates and tested. The Roy-Camille spinal fixation plates were utilized as the stabilizing device. Results are compared with intact motion segments. It is shown that segments C3-4 and C4-5, when severely destabilized by a surgically created defect, can ... View full abstract»

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  • A solid, locked intramedullary nail, for humeral fracture fixation: a biomechanical analysis

    Publication Year: 1991, Page(s):26 - 27
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (235 KB)

    Orthofix, a new solid interlocking intramedullary fracture fixation system, was biomechanically tested in human cadaveric humeri. The interlocking solid nail provides rigid fixation, while the targeting device lessens the need for dynamic intraoperative X-rays. Cadaveric humeri with midshaft, transverse fractures were fixed with either the Orthofix device or Broad dynamic compression plates (DCPs)... View full abstract»

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  • Control of robotic motion with neuron-like elements

    Publication Year: 1991, Page(s):28 - 29
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (163 KB)

    Using a controller made up of models of biological nerve cells, a controller network for a robotic limb was designed that incorporates pertinent environmental information into its motion directives, and does so without the need for conventional computers. Feedback information pertaining to the position, velocity, and acceleration of the robotic limb is encoded into compatible frequency-based signa... View full abstract»

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  • Chaotic statistics of biomedical time series

    Publication Year: 1991, Page(s):33 - 34
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (213 KB)

    New statistical techniques are reviewed that have been developed specifically for the analysis of chaotic systems. These techniques involve new concepts that are largely unrelated to those developed for the analysis of linear systems. Three such techniques are discussed: dimension, entropy, and Lyapunov exponents. All three techniques have a common starting point: embedding the time series. It is ... View full abstract»

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  • Approximate entropy: a complexity measure for biological time series data

    Publication Year: 1991, Page(s):35 - 36
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    Difficulties with, and the possible inappropriateness of, applications of dimension and entropy algorithms to biological data, such as heart rate and electroencephalography (EEG) data, are indicated. A recently developed family of statistics, ApEn, can classify complex systems, given at least 1000 data values in diverse settings that include both deterministic chaotic and stochastic processes. The... View full abstract»

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  • Detection of EEG transients by changes in dimensional complexity

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (31 KB)

    Summary form only given. A simple box accounting algorithm is applied to measure the fractal dimension of electroencephalography (EEG). Artificial transients of varying EEG characteristics are embedded. The change is noted in the fractal dimension within a window that is passed along the entire time series. Three embedded evoked potential spikes 100 ms apart buried anywhere in the time series are ... View full abstract»

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  • The VT model: a deterministic model of angiogenesis and biofractals based on physiological rules

    Publication Year: 1991, Page(s):38 - 39
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (218 KB)

    A vascular tree (VT) model is developed that recreates vascular embryology and anatomy. It is a nonlinear deterministic process defined via topology and set theory. The accuracy of the model is due to its foundations in natural physiology. Real and VT angiogenesis are closed-loop control systems, with vessels growing reactively in response to inputs generated by tissue growth. This system creates ... View full abstract»

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  • Inverse power-law distributions and 1/F power spectra in fetal breathing dynamics

    Publication Year: 1991, Page(s):40 - 41
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (104 KB)

    It is shown that fetal breathing dynamics demonstrate an inverse power-law relationship in the distributions of the inter-burst intervals and in the power spectrum. Furthermore, it is shown how these fractal characteristics change as a function of gestational age of the fetus. The observation of the inverse power-law relationship in the fetal breathing dynamics supports the proposal that fractal m... View full abstract»

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  • Brain death: a simulation study for non-invasive detection

    Publication Year: 1991, Page(s):42 - 43
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    A simulation study done on a mathematical model of the human arterial system from the heart to the eye and the brain is presented. Pressure changes in the eye over time were investigated to delineate cerebral lesions that may be indicators of progressive brain death. It is shown that an inverse relationship exists between intracranial pressure (ICP) and the intraocular pressure (IOP). IOP changes ... View full abstract»

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  • New configurations of the electrocautery hemostat

    Publication Year: 1991, Page(s):47 - 48
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    Several configurations of the electrocautery hemostat (ECH) are investigated. It is shown that a displaced blade retains the grasping feature, as it improves the blade sharpness, resulting in a reduction of tissue damage. A properly configured ECH can be made sharper than a standard commercially available electrosurgical unit (ESU) blade. It is concluded that the smallest area among the hemostat b... View full abstract»

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  • Scaling properties in neural network learning

    Publication Year: 1991, Page(s):49 - 50
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (207 KB)

    Working definitions of learning and learners are examined from the scaling point of view. A back-error propagation neural network was trained to plot sin (x) given an input x (- pi >or= x >or= pi ). The parameters for the simulation are the following: input-output (pattern) pairs=200; input units=1; hidden units=20; output units=1; learning rates=0.1; momentum term constant=0.2; weights and ... View full abstract»

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  • Neural network classification of EEG using chaotic preprocessing and phase space reconstruction

    Publication Year: 1991, Page(s):51 - 52
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    A cognitive mode mapping system is developed that analyzes and classifies electroencephalograph (EEG) signals recorded from four sites of a subject's brain. The subjects produce this EEG data while performing five selected cognitive tasks. The objective of the system is to identify these tasks based on the salient features embedded in the raw EEG signals. Also, due to the demanding requirements of... View full abstract»

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  • Ultrasonic phase-shift oxygen measuring system

    Publication Year: 1991, Page(s):53 - 55
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (194 KB)

    The ultrasonic phase shift due to a change in the total weight of molecules in the propagating medium is utilized to measure the partial concentration of oxygen. A new way to compensate the effect of temperature on the speed of sound is developed to give a reliable and robust measurement system. The developed system had a linearity coefficient of 0.99738 around room temperature (16.64 degrees C) a... View full abstract»

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  • Automated design of custom femoral stem prosthesis

    Publication Year: 1991, Page(s):56 - 59
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    An automatic custom femoral stem capability has been developed and used to design prosthesis for several difficult cases not amenable to off-the-shelf components. The capability is based on the IDEAS package of programs. Computer tomography scan plates are digitized to generate cross-section profiles of inner and outer cortex. From these profiles a solid model is automatically generated. From the ... View full abstract»

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