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At least 235 records · Page 13Linked to original sources
PubMed1994

An overview of software assessment.

Many engineering systems, especially those required to be particularly dependable, traditionally undergo inspections and assessments of safeness and fitness for purpose. Often some form of 'certificate' is provided by the assessment authority. To an increasing degree these systems are beginning to contain software components. The question naturally arises: how can the software component be assessed? This paper explores the feasibility and limitations of software assessment and the link between the process of developing the software and the quality of the resulting software product.

Europe↗
PubMed1994

PACS for radiology conferences--improvement of application software.

The introduction of PACS in a radiology department means that most functions that are available in the film-based system must be included. One important function is the radiology conference. The handling and application programs of digital workstations are normally not developed for demonstrations of many images in a limited time. This paper describes a workstation with specially designed software for radiology conferences. The application is separated in preparation and presentation of the cases to be demonstrated. Very fast image handling is achieved during the conference because the function is based on the principle of prefetching of the selected images. The images are presented on a large screen with high resolution. The experiences of digital radiology conferences are good. However, reference films from previous examinations create extra work because they have to be shown on the conventional lightbox.

Computer Terminals↗
PubMed1994

Microcomputer programs for physiologically-based pharmacokinetic (PB-PK) modeling.

Physiologically-based pharmacokinetic (PB-PK) models are each defined as a set of mathematical equations offering a fairly comprehensive time course of a chemical's disposition in several pre-selected anatomical compartments. Each of these compartments has its characteristic blood flow, volume, tissue-blood partition coefficient, and metabolic or clearance rate constants that together are deemed responsible for a chemical's disposition in that region. Numerous investigators have used these models to predict tissue dose in the animal or human body in recent years. This simulation technique, if proven effective, will eventually reduce the large number of animals that are required in the costly classic, in vivo studies to be conducted for chemical disposition or metabolism. This communication offers 2 affordable micro-computer programs which can be used as a practical simulation tool in further exploring the application of PB-PK modeling in chemical risk assessment. These 2 programs are written especially for investigators who prefer to have some appreciation of the required computer simulation first before committing themselves to using more advanced, expensive simulation software packages that are commercially available.

Administration, Cutaneous↗
PubMed1995

Supercomputer algorithms for efficient linear octree encoding of three-dimensional brain images.

We designed and implemented algorithms for three-dimensional (3-D) reconstruction of brain images from serial sections using two important supercomputer architectures, vector and parallel. These architectures were represented by the Cray YMP and Connection Machine CM-2, respectively. The programs operated on linear octree representations of the brain data sets, and achieved 500-800 times acceleration when compared with a conventional laboratory workstation. As the need for higher resolution data sets increases, supercomputer algorithms may offer a means of performing 3-D reconstruction well above current experimental limits.

Algorithms↗
PubMed1995

A computer program for automatic measurement of respiratory mechanics in artificially ventilated patients.

A program for automatic and periodic determination of respiratory mechanics in artificially ventilated patients is described. Airway pressure and flow signals are obtained from the ventilator in the controlled ventilation mode with constant flow inflation and end-inspiratory pause. Periodically, the program records both signals for a given time and it delimits a ventilatory cycle and its components out of this record. Then, four mechanical parameters of the respiratory system are calculated: (1) Rinit, the resistance obtained with the end-inflation occlusion technique; (2) Ers, the elastance (inspiratory) calculated from the slope of the airway pressure profile during inflation; (3) tau, the expiratory time constant; (4) PEEP, the global positive end expiratory pressure. All parameter measurements have been evaluated in experimental conditions, and are in good agreement with reference values. The complete software includes the display of the signals and of the trends together with automatic disk file backups. An additional program allows one to display the trends again and to create table text files containing all the recorded data for further analysis. The system proved to work in ICU and anaesthesia patients with various ventilators.

Adult↗
PubMed1995

WENDEC: a deconvolution program for processing hormone time-series.

The estimation of the glandular secretory rate from time-series of hormone concentration in plasma can be formulated as a deconvolution problem. In particular, the paper addresses the analysis of frequently sampled data collected in order to study spontaneous pulsatile secretion. Standard deconvolution methods do not allow for the non-negativity constraint and the presence of high-frequency components in the secretory rate. In order to overcome the intrinsic ill-conditioning of the problem, the maximum entropy method is used to obtain a probabilistic representation of the prior knowledge concerning the unknown secretory signal, thus leading to a White Exponential Noise (WEN) model. The deconvolution problem is then posed within a Bayesian framework and solved by means of Maximum-A-Posteriori estimation. The program that implements the algorithm handles non-negativity constraints, provides confidence intervals, and is computationally and memory efficient.

Algorithms↗
PubMed1995

Software tools for using a personal computer as a timer device to assess human kinematic performance: a case study.

Frequently, the assessment of the physical condition of a sportsman depends on the evaluation of different tests, based on biomechanical performance. The data acquisition in these tests is usually hand made, because its automatization is difficult. But when movements are constrained by means of their specific nature, simple tools can be used to achieve that data acquisition. In this paper, a simple and inexpensive system is described to make use of the timing capabilities of a personal computer (PC) to use it as a timer, with applications in biomechanics and sport training. The data acquisition method is based on a PC that, using a specific programming dealing with event timing, gets signals through the printer port, from a receptor device that detects cuts in an infrared cell beam. Low level procedures are provided that can be used in higher level algorithmic designs, problem dependent, to build specific systems. The case of the evaluation of the Wingate Anaerobic Test is discussed.

Algorithms↗
PubMed1995

An event recorder for infant feeding research.

An Event Recorder program was developed for the HP 48 calculator to record the durational events associated with breastfeeding behavior. The Event Recorder menu structure is flexible and allows for the recording of response variables such as menstrual history and fertility symptoms. A Windows program was written in Visual C++ to give a graphical representation of the time-series data and to extract useful measures of breastfeeding activity from the raw data for each 24-h day postpartum. These time varying covariates include the mean and median bout length, median interbout interval, breastfeeding frequency and total 24-h suckling duration. The HP 48 calculator has proven to be a robust instrument for the self-recording of breastfeeding data collected as part of a prospective study on the factors that maintain postpartum amenorrhea. We have found also that the behavioral data collected are easily transferred electronically each month when our field workers make home visits.

Breast Feeding↗
PubMed1995

A software oscilloscope for DOS computers with an integrated remote control for a video tape recorder. The assignment of acoustic events to behavioural observations.

With only a little knowledge of programming IBM compatible computers in Basic, it is possible to create a digital software oscilloscope with sampling rates up to 17 kHz (depending on the CPU- and bus-speed). The only additional hardware requirement is a common sound card compatible with the Soundblaster. The system presented in this paper is built to analyse the direction a flying bat is facing during sound emission. For this reason the system works with some additional hardware devices, in order to monitor video sequences at the computer screen, overlaid by an online oscillogram. Using an RS232-interface for a Panasonic video tape recorder both the oscillogram and the video tape recorder can be controlled simultaneously and moreover be analysed frame by frame. Not only acoustical events, but also APs, myograms, EEGs and other physiological data can be digitized and analysed in combination with the behavioural data of an experimental subject.

Animals↗
PubMed1995

Computer program for performing whole-cell voltage-clamp experiments.

This computer program was designed to be used instead of a stimulator and an oscilloscope in whole-cell voltage-clamp experiments. It runs on IBM XT-AT compatible computers under MS-DOS. The program uses drivers for specific ADC-DAC boards, which are stored in separate files. The driver to be used is loaded on start-up. Drivers for Labmaster TL-1 and CSY-10 are available and the driver for CED 1401 is now being developed. Stimulus waveforms of up to five consecutive pulses are supported. Data may be acquired from up to four input channels, using two ADC sampling rates. The acquired data are visualised on six plots which can be resized and moved independently on the screen in order to obtain a readable picture. A special mode for monitoring the giga-seal formation is supported. There are several data processing procedures, which can be used without interrupting the experiment, including I-V relationships, cursor measurements, addition and subtraction of obtained currents.

Microcomputers↗
PubMed1995

RefVal: a program implementing the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values.

RefVal is a computer program that implements the recommendations of the International Federation of Clinical Chemistry on the statistical treatment of reference values. The program performs the following main tasks: graphical display of the distribution of reference values, identification or elimination of outliers, testing of the fit of the distribution to Gaussian shape (coefficients of skewness and kurtosis, Anderson-Darling's test, Cramér-von Mises' test, Kolmogorov-Smirnov's test), non-parametric and parametric estimation of reference limits (fractiles, percentiles). The parametric estimation method is based on a two-stage mathematical transformation of data: (1) Manly's exponential transformation (to remove skewness) and (2) John and Draper's modulus transformation (to adjust for remaining kurtosis). The program exists in different versions. The paper describes two of these: (1) a library of FORTRAN functions and subroutines and (2) a Pascal PC program that runs under MS-DOS.

Bias↗
PubMed1995

Prediction of polypeptide secondary structures analysing the oscillation of the hydropathy profile.

The hydropathy profile of a polypeptide can reflect periodicity tightly linked, in particular, with alpha-helix and beta-strand conformations. We have developed an algorithm to detect such periodicity to predict the secondary structure of proteins. The method uses profiles constructed with the weighted average of hydropathy along the primary structure of the polypeptide and does the analysis of the variation of the profile for looking for periodic oscillations, using a variation detecting algorithm, without the definition of an empirical threshold. The independence of the method from known structures makes it particularly reliable for analysing membrane proteins.

Algorithms↗
PubMed1996

Clinical evaluation of the DIABETES expert system for decision support by multiple regimen insulin dose adjustment.

A performance evaluation of the DIABETES rule-based expert system prototype for clinical decision making is presented. The system facilitates multiple insulin regimen and dose adjustment of insulin dependent Type I or II diabetic patients. The study was performed on 600 subjects from two diabetological centres and three diabetological offices of Greek hospitals. The responses of the attendant medical doctors were compared with those of the DIABETES system, with the aid of a specifically devised valuation range (0-5 degrees, 0 indicating full agreement and 5 full disagreement). The capabilities and the weakness of the system in terms of its practicality for decision support in assisting therapy of diabetes mellitus by blood glucose monitoring and subsequent insulin dose adjustment are discussed. The potential benefits of decision support systems for diabetic patient management are seen to be the cost saving they provide in terms of man-hours of verbal instruction by medical experts, the support in terms of objective and consistent decision making, as well as the recording of medical knowledge in the ill-defined field of insulin administration, thus aiding the education and training of medical personnel.

Aged↗
PubMed1996

Implementation of OSPOP, an algorithm for the estimation of optimal sampling times in pharmacokinetics by the ED, EID and API criteria.

The most common approach to optimize the sampling schedule in parameter estimation experiments is the D-optimality criterion, which consists in maximizing the determinant of the Fisher information matrix (max det F). In order to incorporate prior parameter uncertainty in the optimal design, other criteria have been proposed: The ED = max E (det F), EID = min E (l/det F) and API = max E (log det F) criteria, where the expectation is with respect to the given prior distribution of the parameters. Previously described algorithm for the estimation of optimal sampling times according to these criteria are adaptive random search (ARS), a robust and global but slow optimizer for API, and stochastic gradient (SG), a fast but local optimizer for ED and EID. We implemented an algorithm named OSPOP 1.0, based on non-adaptive random search (RS) followed by stochastic gradient to determine optimal sampling times for parameter estimation in various pharmacokinetic models according to ED, EID and API criteria. Prior distributions are allowed to be uniform, normal or lognormal. This algorithm combines the robustness of RS and the speediness of SG (convergence is obtained in a few minutes on a microcomputer). The results of the SG algorithm have been compared to those described in the literature using the ARS algorithm on a one compartment model with first- order absorption and were very similar. Also, the CPU time needed by SG and ARS algorithms were compared and the former proved to be much faster. Then, it has been applied to a five parameters stochastic model with zero-order absorption rate and Weibull-distributed residence times which was shown to describe adequately the kinetics of metacycline in humans. Population pharmacokinetic parameters of metacycline were estimated from a six subject pilot study, by the iterative two-staged method, using ADAPT II repeatedly. Optimal sampling times were determined with each criterion (ED, EID, API) with a multivariate normal prior parameter distribution. Six to seven distinct sampling times could be estimated. Higher numbers of samples revealed coalescing of design points.

Algorithms↗
PubMed1996

Analysis of pressurized resistance vessel diameter changes with a low cost digital image processing device.

A low cost digital image processing device (frame grabber) together with a program running under MS_WINDOWS for automatic on-line analysis of diameter changes of in vitro pressurized blood vessels with an inner diameter of 80-400 microns is presented. The frame grabber is designed to receive light microscopic images either from a video camera or from a VCR and to present the digitized image on the computer monitor. The special software allows to manipulate the image, e.g. filtering, calibrating, storing of vessel images, and detects the outer and inner border of the two vessel walls with a new, simple algorithm. The inner diameter and the vessel wall thickness are calculated and the diameter is presented in a diameter versus time diagram on the monitor screen. Further, these data are stored in an ASCII-file for later import into calculation and presentation programs like MS-EXCEL.

Algorithms↗
PubMed1996

Add-in macros for rapid and versatile calculation of non-compartmental pharmacokinetic parameters on Microsoft Excel spreadsheets.

We developed a package of macro programs (named PK_MOMENT) to automatically calculate non-compartmental pharmacokinetic parameters on Microsoft Excel spreadsheets. These macros include rigorous algorithms to execute moment calculations in a comprehensive manner. An optimum number of terminal data points for infinite-time extrapolation can be calculated with one of these macros so that automatic calculation of infinite moment parameters is possible. The moment calculation with PK_MOMENT provided satisfactory results using the hybrid (mixed linear-logarithmic) trapezoidal method rather than the conventional linear trapezoidal method. The macro-aided pharmacokinetic analyses turned out to be useful in that the macro-containing cells can be easily copied and pasted to analyze other data sets and that powerful tools of Excel can be utilized. The use of our macros will be significantly time-saving for routine pharmacokinetic analyses, considering that pharmacokinetic data are usually stored in a spreadsheet format, typically with Excel.

Administration, Oral↗
PubMed1996

Implementation of a reference management system, MacRefer, under HyperCard.

We have developed a reference management system, MacRefer, using HyperTalk on Macintosh personal computers. Using this program, one can automatically acquire data from databases created by EndNote Plus and from OVID- or Medlar-formatted records downloaded via an online use of Medline. The MacRefer's capability of formatting bibliographic database in user-defined formats is comparable with the exemplified bibliography maker, EndNote Plus. Moreover, MacRefer has several competitive features, which are insufficiently equipped with EndNote Plus. For example, MacRefer is capable of (1) maintaining subsets within a database, (2) executing complex, structured searches combining up to nine keywords for any data field with the results and search conditions preserved, and (3) easily browsing (a portion of) reference database. Although MacRefer cannot be recognized as an absolute alternative of EndNote Plus because of several limitations inherent to HyperCard, the compensatory use of these two programs will expand the personal utilization of bibliographic databases.

Computers↗
PubMed1996

A computer program for comprehensive ST-segment depression/heart rate analysis of the exercise ECG test.

The ST-segment depression/heart rate (ST/HR) analysis has been found to improve the diagnostic accuracy of the exercise ECG test in detecting myocardial ischemia. Recently, three different continuous diagnostic variables based on the ST/HR analysis have been introduced; the ST/HR slope, the ST/HR index and the ST/HR hysteresis. The latter utilises both the exercise and recovery phases of the exercise ECG test, whereas the two former are based on the exercise phase only. This present article presents a computer program which not only calculates the above three diagnostic variables but also plots the full diagrams of ST-segment depression against heart rate during both exercise and recovery phases for each ECG lead from given ST/HR data. The program can be used in the exercise ECG diagnosis of daily clinical practice provided that the ST/HR data from the ECG measurement system can be linked to the program. At present, the main purpose of the program is to provide clinical and medical researchers with a practical tool for comprehensive clinical evaluation and development of the ST/HR analysis.

Exercise Test↗