Biomedical subjects

P Frenger

Publications and source records attributed to P Frenger.

At least 19 recordsLinked to original sources

PubMed2001

Human sensory subsystems emulator.

Last year this author presented his design for a computerized human nervous system function emulator for use in an android robot. This paper describes that emulator's sensory subsystems in more detail and adds new functions. Topics covered include sensor types, signal conditioning, data handling in the afferent pathways and interpretation of sensory information. Physiological sensory modalities (including: temperature, pressure, acceleration, humidity, sound and light stimuli) as well as nonphysiological (including: magnetic, radio, infrared, ultrasound and satellite GPS) are elucidated. The relationship of a primitive stimulus (i.e.: heat) to a high level sensation (i.e.: pain) is explored.

Biomedical Engineering↗

PubMed2000

Human nervous system function emulator.

This paper describes a modular, extensible, open-systems design for a multiprocessor network which emulates the major functions of the human nervous system. Interchangeable hardware/software components, a socketed software bus with plug-and-play capability and self diagnostics are included. The computer hardware is based on IEEE P996.1 bus cards. Its operating system utilizes IEEE 1275 standard software. Object oriented design techniques and programming are featured. A machine-independent high level script-based command language was created for this project. Neural anatomical structures which were emulated include the cortex, brainstem, cerebellum, spinal cord, autonomic and peripheral nervous systems. Motor, sensory, autoregulatory, and higher cognitive artificial intelligence, behavioral and emotional functions are provided. The author discusses how he has interfaced this emulator to machine vision, speech recognition/speech synthesis, an artificial neural network and a dexterous hand to form an android robotic platform.

Artificial Intelligence↗

PubMed1999

Linear circuits for neural networks and affective computing.

Biological phenomena are often modeled with software on digital computers, even though the events may be analog in nature. The author describes the use of linear circuitry in two areas of biological simulation: artificial neural networks and affective computing. The operational amplifier, with the assistance of some new analog chips and simple digital microcontrollers, is featured prominently in these linear designs.

Computer Simulation↗

PubMed1997

Photorealistic speech agents and facially expressive robots.

In an ideal human-computer interface, the computer would be able to understand and use modalities such as speech, hearing, facial gestures and body language in as realistic and natural a manner as a human. This paper discusses two kinds of computer-to-human interaction techniques which involve computerizea facial gestures: the first is the graphics representation of the human face projected on a video display; the second is the physical embodiment of facial expressions using an android robot. These simulated facial gestures may be accompanied by computerized speech synthesis, voice recognition capability or machine vision for recognition of the facial expressions of the human viewer. The author reviews both major techniques, then discusses current and proposed applications of this methodology.

Computer Simulation↗

PubMed1997

Artificial vision workbench.

Machine vision is an important component of medical systems engineering. Inexpensive miniature solid state cameras are now available. This paper describes how these devices can be used as artificial retinas, to take snapshots and moving pictures in monochrome or color. Used in pairs, they produce a stereoscopic field of vision and enable depth perception. Macular and peripheral vision can be simulated electronically. This paper also presents the author's design of an artificial orbit for this synthetic eye. The orbit supports the eye, protects it, and provides attachment points for the ocular motion control system. Convergence and image fusion can be produced, and saccades simulated, along with the other ocular motions. The use of lenses, filters, irises and focusing mechanisms are also discussed. Typical camera-computer interfaces are described, including the use of "frame grabbers" and analog-to-digital image conversion. Software programs for eye positioning, image manipulation, feature extraction and object recognition are discussed, including the application of artificial neural networks.

Artificial Organs↗

PubMed1996

Nanocontrollers for biomedical applications.

Several semiconductor companies now manufacture low cost single-chip microcontrollers in dual inline packages having twenty or fewer pins. The controllers are field programmable by means of inexpensive development boards linked to personal computers. These processors were designed with a minimalist philosophy which provide them with only a few dozen bytes of on-chip RAM, hundreds of bytes of PROM, a parallel port, a counter/timer, and reduced instruction sets. The better-equipped members of this class may have special on-chip hardware, such as analog-to-digital input, pulse-width modulation output and a serial port. Most must be programmed in assembler, although some support BASIC, "C" or other languages. Their tiny size, design simplicity and operational single-mindedness earn them the nickname "nanocontrollers". Despite meager resources, these controllers can be successfully employed in a variety of biomedical applications. Such uses include: consolidation of multi-chip "glue logic" circuitry; functioning as subsystem elements in complex designs; serving as device drivers or protocol converters; and forming the building blocks of hypercube processor arrays or artificial neural networks. This paper describes the general capabilities, special features, and some application examples of "nanocontroller" technology.

Biomedical Engineering↗

PubMed1995

Inexpensive complex hand model.

This paper describes a functional model of the human hand suitable for design and testing of various motion control systems. A five digit arrangement (four fingers with opposable thumb) with anthropomorphic joints is used which provide a physiologic range of motion from the phalanges through the wrist. These joints can be operated by various actuators (ie: contractile wire, stepper motors, hydraulics, pneumatics) with or without position/force feedback sensors. The construction techniques utilize cheap, readily obtainable materials which can easily be formed and assembled with common modelmaker's tools. Students and teaching laboratories will be able to afford the basic hand system. The model is sophisticated enough to serve as a platform for non-trivial applications such as research (prosthetics/rehabilitation), teaching, and aids for the handicapped. Construction plans are available from the author.

Biomechanical Phenomena↗

PubMed1994

Inexpensive speech recognition techniques.

Improvements in technology have enabled creation of speech recognition hardware and software products which are easily affordable. This paper briefly reviews these techniques and describes several commercially available products which utilize them. Both speaker-dependent and speaker-independent techniques are included. The author concludes by describing a microprocessor-controlled, trainable, voice recognition board which he built for medical applications which is based on a commercial $5 speech recognition integrated circuit.

Computers↗

PubMed1993

Biomedical uses of shape memory polymers.

A new type of plastic polymeric material is described which can dramatically change its physical properties with temperature. These changes include hardness, flexibility, modulus of elasticity and shape. These changes occur within a very narrowly defined range of temperatures, which can be controlled in the manufacturing process. These "memory resins" can be formed by casting, extruding, injection molding and solution coating into a rigid form which has low cytotoxicity. Warming followed by cooling allows forming of the material; the new shape is retained until the part is rewarmed and recooled, at which time the part reverts to its original manufactured shape. The author describes several current and proposed uses for these shape memory polymers.

Biocompatible Materials↗

PubMed1992

Contractile wire biomechanical actuators.

Several metal alloys have been discovered which, when fabricated into wire, contract strongly when heated and relax with cooling. The contractile force can be modulated under microcomputer control to produce a compact, powerful and durable mechanical actuator. This technique has a number of advantages over motor-driven servos in robotics and medicine. This paper reviews previous applications of contractile wire, then presents two types of biomechanical actuators built by the author.

Alloys↗

PubMed1991

A software-controlled EKG simulator.

This design allows generation of a wide range of waveforms from subaudio to ultrasonic directly via software. Waveforms may be calculated on the fly by suitable algorithms or produced from previously created lookup tables. The heart of the design is a fast 16-bit processor which directly executes the Forth programming language. A simple R/2R digital-to-analog converter is coupled to a parallel output port to produce the desired waveforms. This device has been used to generate realistic-appearing normal and abnormal EKG tracings in the lab.

Algorithms↗

PubMed1990

Medicine in the twenty-fourth century.

This paper discusses one vision of medicine's future as penned by a noted current writer of science fiction. Medical progress is seen as an outgrowth of the overall advancement of human technology, especially as a result of routine exploration of deep space. Much of 24th century medicine is to be based on the merging of bioengineering with the classical medical arts. A great deal more will be known about the human animal then than now, so more healing can be done. In spite of numerous items of medical gadgetry at his disposal, the physician of 400 years hence will remain sympathetic and caring.

Forecasting↗

PubMed1989

The silicon synapse or, neural net computing.

Recent developments have rekindled interest in the electronic neural network, a form of parallel computer architecture loosely based on the nervous system of living creatures. This paper describes the elements of neural net computers, reviews the historical milestones in their development, and lists the advantages and disadvantages of their use. Methods for software simulation of neural network systems on existing computers, as well as creation of hardware analogues, are given. The most successful applications of these techniques, involving emulation of biological system responses, are presented. The author's experiences with neural net systems are discussed.

Artificial Intelligence↗

PubMed1988