Showing papers on "Personal computer published in 1990"

New developments in laser resonators

Abstract: This paper gives brief descriptions of three recent developments not so much in laser resonators themselves as in the tools for analyzing and measuring the quality of laser beams and resonators. These tools include personal computer programs for analyzing laser beams and resonators; a new method for characterizing and measuring the "beam quality" of a laser output beam; and a new "ray-pulse" method of analysis for describing beams and resonators which involve any combination of ultrashort optical pulses, broadband optical signals, and dispersive optical elements.

A guide to the effective use of otoacoustic emissions.

Abstract: Otoacoustic emission test instruments are now entering routine audiological practice. Two general classes of technique are in use in laboratory work--those employing spectrum analysers to observe the continuous generation of OAEs, both stimulated or unstimulated, and those using transient stimulation and waveform averaging to extract a delayed OAE or "cochlear echo" waveform from ear canal sound. Both methods have particular advantages in clinical applications. The transient OAE type of method has proved very effective in screening applications, particularly in neonates. It is possible to perform noninvasive screening acoustic cochleography in about a minute. The technique is also useful for characterizing cochlear mechanical status prior to long term monitoring. Achieving routinely reliable OAE test performance in clinical and screening applications under nonideal conditions makes special demands on the instrumental design and the response evaluation procedures. The essential requirements are reviewed and discussed in a general and specific context. We have tried to meet these requirements in a transient evoked otoacoustic emission system (the ILO88) which we designed to operate with a personal computer. We report on our design of probe, and our use of evaluation procedures for probe fit, and response quality. Signal processing methods have been developed to reject noncochlear acoustic responses, and to optimise the rejection of patient noise. Examples of its clinical use, and the practical problems typically encountered are given here.

Assessment of the distensibility of superficial arteries.

Abstract: Doppler signal processing cannot only be employed to detect the local blood velocity as function of time, but also to assess transcutaneously the displacement of the arterial walls during the cardiac cycle (distension waveform) and, hence, the time-dependent changes in arterial diameter relative to its initial diameter at the start of a cardiac cycle. The distension waveform normalized with respect to the local pulse pressure provides useful information about the local elasticity of the arterial wall. The displacement of the arterial wall can be obtained by processing the RF-signals within a sample volume coinciding with the arterial wall. To evaluate this method a dedicated high-speed memory system has been developed storing the RF-signal, as obtained with a conventional echo-imager in M-mode, over a number of successive sweeps covering a selected depth range. The data are transferred line after line to a personal computer (PC) and processed on the fly, thereby relieving the memory requirements of the PC. It can be concluded that a RF-signal memory in combination with a PC provides a useful tool to extract detailed diameter waveforms from the RF-signals obtained. Although the system does not process the signals in real-time the process can be considered to be on-line since the results become available within one minute after the acquisition of the data is completed.

Diabetes data analysis and interpretation method

Abstract: An automated diabetes data interpretation method is provided which combines symbolic and numeric computing approaches in order to identify and highlight key clinical findings in the patient's self-recorded diabetes data. The patient data, including blood glucose levels and insulin dosage levels, recorded by a diabetic patient over a period of time by means of a glucose meter or the like, is initially downloaded into a central processing system such as a personal computer. The accepted diabetes data is subsequently processed to (a) identify insulin dosage regimens corresponding to predefined significant changes in insulin dosage which are found to be sustained for at least a predefined segment of the overall data collection period, (b) identify statistically significant changes in blood glucose levels resulting across adjacent ones of the identified insulin regimen periods, and (c) identify clinically significant changes in blood glucose levels from within the identified statistically significant glucose level changes. The results of the diabetes data processing are generated in the form of a comprehensive yet easily understandable data interpretation report highlighting the processing results, including details pertaining to the identified insulin regimens and the associated clinically significant changes in glucose levels.

Test-Retest Reliability of the Biodex Isokinetic Dynamometer

Abstract: The purpose of this study was to determine the test-retest reliability of the Biodex (Biodex, Corp., Shirley, NY) isokinetic concentric mode for a healthy active population for knee extension/flexion utilizing the parameters peak torque and work. Nineteen healthy active male and female subjects ages 20-35 with no history of knee injury were tested bilaterally for concentric knee extension and flexion at 60, 180, 240, and 300 degrees /sec., utilizing standard Biodex protocol. Seven days following the pre-test, a post-test was administered using identical protocol. Data collection of pre- and posttesting was done via a Compaq Desk Pro personal computer and Biodex software programming. The parameters of peak torque and single repetition work were analyzed for knee extension/flexion. Statistical analysis of data showed the intraclass correlation coefficient (ICC) of knee extension peak torque at 60 degrees /sec to be r = 0.95; at 180 degrees /sec, r = 0.96; at 240 degrees /sec, r = 0.95; and at 300 degrees /sec, r = 0.97. Knee extension work ICC values were at 60 degrees /sec, r = 0.96; at 180 degrees /sec, r = 0.97; at 240 degrees /sec, r = 0.96 and r = 0.95 at 300 degrees /sec. All ICCs are significant at the 0.05 level. Therefore, the isokinetic concentric mode of the Biodex dynamometer was reliable for test-retest measures of peak torque, and single repetition work. J Orthop Sports Phys Ther 1990;11(7):298-300.

System for Automating and Multiplexing Soil Moisture Measurement by Time-Domain Reflectometry

Abstract: It is often necessary to measure soil water content at multiple points in space and time. Our goal was to develop an automated and multiplexed measurement system using time-domain reflectometry (TDR). Two systems are described; the first (A) uses an analog TDR unit, in which voltage signals sent from the TDR to a datalogger convey the shape of the waveform. The second (D) uses a digital TDR that communicates a digital representation of the oscilloscope wave to a personal computer. Both systems use the same multiplexing strategy, in which the TDR transmission line connects through a 12-position rotary switch to various waveguides positioned in the soil and to further rotary switches. The switches are turned by stepping solenoids that are activated by the datalogger in System A and the computer in System D. System D uses software to automatically analyze the incoming waveforms and calculate volumetric water content. Some of the possible uses of each system include observation of infiltration at multiple points within a field and measurement of unfrozen water content as a function of space and time during freezing and thawing. The system has also been used to estimate the reproducibility of water content measurement by TDR, which was found to be in the range of ±0.006 to ±0.008. The systems described should be useful for field research on many subjects, including studies of transport and biological processes in soil, and validation of root water-uptake models.

Matrix methods applied to acoustic waves in multilayers

Abstract: Matrix methods for analyzing the electroacoustic characteristics of anisotropic piezoelectric multilayers are described. The conceptual usefulness of the methods is demonstrated in a tutorial fashion by examples showing how formal statements of propagation, transduction, and boundary-value problems in complicated acoustic layered geometries such as those which occur in surface acoustic wave (SAW) devices, in multicomponent laminates, and in bulk-wave composite transducers are simplified. The formulation given reduces the electroacoustic equations to a set of first-order matrix differential equations, one for each layer, in the variables that must be continuous across interfaces. The solution to these equations is a transfer matrix that maps the variables from one layer face to the other. Interface boundary conditions for a planar multilayer are automatically satisfied by multiplying the individual transfer matrices in the appropriate order, thus reducing the problem to just having to impose boundary conditions appropriate to the remaining two surfaces. The computational advantages of the matrix method result from the fact that the problem rank is independent of the number of layers, and from the availability of personal computer software that makes interactive numerical experimentation with complex layered structures practical. >

Short term load forecasting of Taiwan power system using a knowledge-based expert system

Abstract: A knowledge-based expert system was developed for the short-term load forecasting of the Taiwan power system. The developed expert system, which was implemented on a personal computer, was written in PROLOG using a 5-year database. To benefit from the expert knowledge and experience of the system operator, eleven different shapes, each with different means of load calculations, were established. With these load shapes at hand, some peculiar load characteristics pertaining to the Taiwan Power Company can be taken into account. The special load types considered by the expert system include the extremely low load levels during the week of the Chinese New Year, the special load characteristics of the days following a tropical storm or a typhoon, the partial shutdown of certain factories on Saturdays, the special event caused by a holiday on Friday or on Tuesday, etc. A characteristic feature of the knowledge-based expert system is that it is easy to add new information and new rules to the knowledge base. To illustrate the effectiveness of the system, short-term load forecasting is performed on the Taiwan power system by using both the developed algorithm and the conventional Box-Jenkins statistical method. It is found that a mean absolute error of 2.52% for one year is achieved by the expert system approach as compared to an error of 3.86% by the statistical method. >

Exponentiation cryptosystems on the IBM PC

Abstract: Several cryptosystems based on exponentiation have been proposed in recent years. Some of these are of the public key variety and offer notable advantages in cryptographic key management, both for secret communication and for message authentication. The need for extensive arithmetic calculations with very large integers (hundreds of digits long) is a drawback of these systems. This paper describes a set of experimental programs that were developed to demonstrate that exponentiation cryptosystems can be efficiently implemented on the IBM Personal Computer (PC). The programs are organized into four layers, comprising procedures for: multiple precision integer arithmetic, modular exponentiation, prime number generation and testing, and cryptographic key generation. The major emphasis of the paper is on methods and techniques for improving execution speed. The items discussed include: the use of a specialized squaring procedure; a recursive splitting method to speed up squaring and multiplication; the computation of residues by using multiplication instead of division; the efficient encoding of residue information; and the use of thresholds to select the most effective primality testing algorithm for a given size number. Timing results are presented and discussed. Finally, the paper discusses the advantages of a mixed system that combines the superior key management capabilities inherent in public key cryptosystems with the much higher bulk-encryption speed obtainable with the Data Encryption Algorithm.

SIMION PC/PS2 electrostatic lens design program

Abstract: SIMION PC/PS2 4.02 is a personal computer program for designing and analyzing charged particle (ions and electrons) lenses, ion transport systems, and various types of mass spectrometers and surface probes that utilize charged particles. The modification of an existing design or the generation of a completely new one is performed interactively with a graphics screen and mouse. Once the geometry has been defined, the operating conditions (electrode voltages and magnetic field configuration) can be quickly changed and the resultant fields viewed in several different 2D and 3D modes. The trajectories of charged particles moving in these fields are calculated utilizing sophisticated ‘‘look‐ahead’’ algorithms that dynamically control the time step to optimize speed and accuracy. A unique graphics display of the electrostatic fields and ion trajectories gives the user an intuitive, easily understood view of the performance characteristics. simion also includes a totally integrated capability for users to easily...

Efficient numerical methods for infiltration using Richards' equation

Abstract: Two efficient finite difference methods for solving Richards' equation in one dimension are presented, and their use in a range of soils and conditions is investigated. Large time steps are possible when the mass-conserving mixed form of Richards' equation is combined with an implicit iterative scheme, while a hyperbolic sine transform for the matric potential allows large spatial increments even in dry, inhomogeneous soil. Infiltration in a range of soils can be simulated in a few seconds on a personal computer with errors of only a few percent in the amount and distribution of soil water. One of the methods adds points to the space grid as an infiltration or redistribution front advances, thus gaining considerably in efficiency over the other fixed grid method for infiltration problems. In 17-s computing, this advancing front method simulated infiltration, redistribution, and drainage for 50 days in an inhomogeneous soil with nonuniform initial conditions. Only 16 space and 21 time steps were needed for the simulation, which included early ponding with the development and dissipation of a perched water table.

Disk operating system loadable from read only memory using installable file system interface

Abstract: A data processing system, such as a personal computer, contains bootable DOS programs that are stored in a ROM as an alternate file system in which the files are stored in packed format. When the system is powered on, the programs are rapidly booted up or loaded from ROM into RAM and executed to "instantly" (as it appears to the user) place the system in operation.

Transient electromagnetic inversion: A remedy for magnetotelluric static shifts

Abstract: Surficial bodies can severely distort magnetotelluric (MT) apparent resistivity data to arbitrarily low frequen- ties. This distortion, known as the MT static shift, is due to an electric field generated from boundary charges on surficial inhomogeneities, and persists throughout the entire MT recording range. Static shifts are manifested in the data as vertical, parallel shifts of log-log apparent resistivity sounding curves, the impedance phase being unaffected. Using a three-dimensional (3-D) numerical modeling algorithm, simulated MT data with finite length electrode arrays are generated. Significam.staticshifts are produced in this simulation; however, for some geometries they are impossible to identify. Techniques such as spatial averaging and electromag- netic array profiling (EMAP) are effective in removing static shifts, but they are expensive, especially for correct- ing a previously collected MT data set. Parametric repre- sentation and use of a single invariant quantity, such as the impedance tensor determinant, are only useful in lim- ited circumstances and can lead the MT interpreter astray. Transient electromagnetic (TEM) sounding data are rela- tively inexpensive to collect, do not involve electric field measurements, and are only affected at very early times by surficial bodies. Hence, using TEM data acquired at the same location provides a natural remedy for the MT static shift. We describe a correction scheme to shift distorted MT curves to their correct values based on I-D inversion of a TEM sounding taken at the same location as the MT site. From this estimated 1-D resistivity structure an MT sounding is computed at frequencies on the order of 1 Hz and higher. The observed MT curves are then shifted to the position of the computed curve, thus eliminating static shifts. This scheme is accurate when the overlap region between the MT and TEM sounding is l-D, but helpful information can be gleaned even in multidimensional envi- ronments. Other advantages of this scheme are that it is straightforward to ascertain if the correction scheme is being accurately applied and it is easy to implement on a personal computer.

Analysis of multilayer thin-film structures containing magneto-optic and anisotropic media at oblique incidence using 2×2 matrices

Abstract: A complete analysis of multilayer structures containing an arbitrary number of dielectric, metal, magnetic, and birefringent/dichroic layers is presented. An algorithm, based on simple 2×2 matrices, is derived which allows reflection, transmission, absorption, magneto‐optic conversion, birefringence, and dichroism of the structure to be computed on a personal computer. The incident beam is assumed to be plane monochromatic with arbitrary angle of incidence. There are no approximations involved, and the results are direct consequences of Maxwell’s equations.

The complex propagation constant of multilayer waveguides: an algorithm for a personal computer

Abstract: An algorithm for the calculation of the propagation constant of integrated-optics waveguides is developed. The waveguide may consist of any number of layers with complex refractive indexes due to gain and loss. It allows the additional determination of the field distribution. Thus, all parameters necessary for heterostructure laser development can be calculated. The resulting program was run on a personal computer; numerical results are presented. >

Three-dimensional spatial registration and interactive display of position and orientation of real-time ultrasound images.

Abstract: Ultrasound images may be difficult to interpret because of the lack of an image orientation display. To resolve this problem, a three-dimensional (3-D) ultrasound scanner has been constructed that provides spatial registration and display of position and orientation of real-time images while allowing unconstrained movement of the scanning transducer. It consists of a conventional sector scanner, a 3-D acoustical spatial locater, and a personal computer. It displays within each image the line of intersection of two image planes, a reference image, and a live image. This display guides and documents image positioning. The scanner's 3-D data also provide the potential for computergraphic modeling of organs, the ability to calculate volumes using nonparallel, nonintersecting image planes, and the capability for 3-D color flow mapping and measurement of Doppler angle.

Educational/board game apparatus

Abstract: Method and apparatus for educational games comprising a plurality of printed cards/boards, and a novel low-cost touch pad with interface cable to the personal computer game-port. When an eductional game is played, the player responds to computer questions/words/graphic object by pressing the corresponding answer in the printed card/board which is placed on top of the touch pad. This selection in terms of touched coordinates of the touch pad is sensed by the computer through the computer input/game port. Both computer generated sound and animation graphic pictures in terms of video games or others are used for either positive or negative feedback to the player. A variation of the same apparatus can be used for playing various computerized board games with a plurality of moving game pieces, and game boards by one or more players.

Data redundancy and recovery protection

Abstract: A method for detecting the presence of a replacement disk in a fault tolerant, intelligent mass storage disk array subsystem having a microprocessor based controller in a personal computer system and rebuilding the replacement disk independent of the computer system processor. The method calls for the microprocessor controller to run a disk array check at system powerup or at specified intervals at which will detect the existence of a replacement drive. The microprocessor then builds a series of disk drive commands which attempt to read every sector on the replacement disk. The read commands will return a null data read, indicating that the sector must be restored. The microprocessor controller converts the replacement read commands for all sectors on the replacement disk to write-restore commands. The microprocessor executes the write commands and restores the data to the replacement drive.

Testing system including removable storage means for transfer of test related data and means for issuing a certification upon successful completion of the test

Abstract: A computer-controlled testing and licensing system is provided for administering a test to a plurality of users on individual, portable, microprocessor-controlled user testing devices. A license is issued to each user passing the test. Each testing device is microprocessor-controlled and includes an information storage medium such as a RAM card for storing information such as test questions and the user's answers thereto. A display on the device displays output information such as test questions from the information storage medium to the user. User entry pads are displayed at predetermined locations on the display for use in permitting the user to input predetermined information to the information storage medium. A touch screen cooperates with the display to enable the user to input selected predetermined input information such as the test answers by touching the screen at a selected user entry pad while such entry pad is displayed on the display. A personal computer is provided for issuing licenses and for storing information such as the test questions, an answer key to the test, and a comparison procedure to enable the computer to provide the test results. An interface device, such as a card reader, is connected with the computer to cooperate with the RAM card of the testing device to permit information to be transferred between the RAM card and the personal computer.

Desktop forms order system

Abstract: The creation and ordering of custom business forms is simplified for short-run orders, allowing the end user of the business form to design and transmit the order on a personal computer. Using appropriate design software, the business form is first designed, and then electronically transferred into a second software program which allows for the selection of a number of business form parameters, and also includes order parameters including quantity and delivery options. The business form parameters from the design software are automatically transferred to the ordering software, and any remaining parameters that must be selected are then selected in a sequence, the order quantity and delivery information is inputted, and the price is calculated, and then the custom business form and order are transmitted in machine form to a second computer remote from the first computer. At the second computer a confirmation of the order is produced, and the order is evaluated to determine where the best facility to print it is. The order is then electronically transferred to the printing location, and after printing it is shipped. The particular manner of highlighting and/or pictorially illustrating the options selectable, and a number of the particular parameters to be selected--such as the edge along which multipart forms are to be attached--are controlled for optimum utility.

Eye-gaze word processing

Abstract: Erica is a personal computer operated by eye-gaze. By looking at menu options displayed at different locations on the computer monitor, a disabled user can invoke commands without the need for standard input devices. The design of test entry software for Erica's gaze word processor is described. A basic encoding is accomplished through a static tree-structured menu system, which associates the 85 most common ASCII characters with unique sequences of menus and eye-gaze picks. The expected length of the pick sequences is minimized based on the approximate frequencies of individual characters determined from a 55882 character corpus of English language text. Text entry speeds are further enhanced by adding context-sensitive nodes to the static tree. The menu screens corresponding to these nodes contain the five characters most likely to follow the last two characters entered, based on character transition probabilities derived from the sample corpus. >

Video image bank for storing and retrieving video image sequences

Abstract: A video image bank system for preparing an edit tape and associated edit list from a library of stock video image sequences uses a set of video disks with an associated library index. A microprocessor or personal computer is loaded with the library index, and an operator selects an initial set of image sequences from a menu or by using key words, specifically or highlighted in a word processor text file, for a desired effect. Groups of still frames, one from each identified image sequence, are displayed and the operator selects any one of the represented image sequences for addition to the edit tape and the associated edit list. Once all the desired stock video image sequences have been selected from the library and transferred to the edit tape and associated edit list, these sequences may readily be added to a production video sequence using normal editing procedures.

An Implantable Neurocybernetic Prosthesis System

Abstract: Summary: The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse generator that delivers constant current electrical signals to the vagus nerve for the purpose of reducing the frequency and/or severity of epileptic seizures. The device is implanted in a subcutaneous chest pocket just below the clavicle, similar to cardiac pacemaker placement. The stimulation signal is transmitted from the prosthesis to the vagus nerve through a stimulation lead. The prosthesis can be programmed using any IBM-compatible personal computer with programming software and a programming wand. The electrodes used in the first group of patients were found to break at an unacceptable rate. Design modifications appear to have resolved this problem.

Decision criteria for computer-aided parting surface design

Abstract: A scientific approach is presented and the related logic developed for design of parting surfaces of patterns, moulds and dies used in the manufacture of cast, forged, injection-moulded and die-cast components. This has enabled computer-aided generation of parting surfaces and the determination of projected area, flatness and draw for a parting surface, identification of surfaces to which draft is provided, recognition of component segments causing undercuts, testing for dimensional stability, and location of flash, machined surfaces and feeders. Influencing criteria for parting-surface design have been formulated and developed into algorithms implemented on a personal computer. This approach greatly aids the engineer in rational decision making, paving the way for a systemized code for parting-surface design.

Construction of a versatile microsecond time-resolved infrared spectrometer

Abstract: A time-resolved scanning infrared spectrometer has been constructed which consists of a globar light source, a monochromator, an MCT detector, a boxcar integrator, a cw Q-switched Nd:YAG laser, and a personal computer. Both the time-resolved spectra (in the frequency-scanning mode) and the temporal change of the transient signals (in the time-scanning mode) can be observed with this spectrometer. It covers the spectral range of 700 to 4200 cm−1 with the time resolution of 1 μs. Intensity changes as small as one part in 104 can be detected with a slit width of 5 mm (6 cm−1 at 700 cm−1 and 60 cm−1 at 4000 cm−1) and with a typical scanning rate of 20 cm−1/min. High performance of this spectrometer has been achieved by the use of a high-repetition-rate (750 Hz) laser for the actinic light source combined with an ac-coupled detection scheme.

Apparatus and method for loading bios into a computer system from a remote storage location

Abstract: This invention relates to personal computer systems and in particular to an apparatus and method for loading BIOS into a personal computer system from a remote storage location. More particularly, this invention provides a personal computer adapted for use as an economical workstation in a local area network environment (a "LAN station") with provision for loading BIOS into the LAN station from a remote memory storage where the BIOS code is maintained apart from the LAN station.

Hard drive security system

Abstract: A security system to prevent un-authorized access to the hard drive of a personal computer system. The security system consists of a plug-in expansion card containing a program on an EPROM, a device driver program which requests the password for access, and other programs to establish the valid passwords for the security system, provide an audit trail of computer access, and other functions. The program on the EPROM disables the floppy drives until a valid password has been entered, forcing the booting process to be controlled and forcing the computer to boot off of the hard drive and request a password via the device driver. A skilled programmer, even with a complete knowledge of the security system's details of operation, can not write a program which can be booted off of a diskette in order to bypass the security system. The passwords and user IDs for the security system are stored on the hard drive of the computer inside the device driver program. The elimination of the need to provide any random access memory, EEROM or other non-volatile memory in which to store the passwords contributes to the low manufacturing cost for the security system.