Influence of noise on wave boundary recognition by ECG measurement programs. Recommendations for preprocessing

In the international cooperative project entitled "Common Standards for Quantitative Electrocardiography" (CSE) systematic noise tests have been performed in order to compare measurement results of electrocardiographic computer programs under degraded operational conditions and to develop recommendations for preprocessing and measurement strategies. The influence of seven different high- and low-frequency noise types on the recognition of P, QRS, and T wave onsets and offsets was investigated. The analysis was performed on 160 electrocardiograms derived from two sets of 10 cases each, by eight electrocardiographic and six vectorcardiographic computer programs. The stability and precision of these programs were tested with respect to the results obtained (1) in the noise-free recordings and (2) by a group of five cardiologists who have analyzed the recordings previously in a Delphi reviewing process. Increasing levels of high-frequency noise shifted the onsets and offsets of most programs outward. Programs analyzing an averaged beat showed significantly less variability than programs which measure every complex or a selected beat. On the basis of the findings of the present study, a measurement strategy based on selective averaging is recommended for diagnostic ECG computer programs. However, averaging should be performed only if proper alignment and precise waveform comparison have been performed beforehand in order to exclude dissimilar complexes.     

MinGPU: a minimum GPU library for computer vision

In the field of computer vision, it is becoming increasingly popular to implement algorithms, in sections or in their entirety, on a graphics processing unit (GPU). This is due to the superior speed GPUs offer compared to CPUs. In this paper, we present a GPU library, MinGPU, which contains all of the necessary functions to convert an existing CPU code to GPU. We have created GPU implementations of several well known computer vision algorithms, including the homography transformation between two 3D views. We provide timing charts and show that our MinGPU implementation of homography transformations performs approximately 600 times faster than its C++ CPU implementation.

Professor-created computer programs for student research

Many university students are eager to use computers to analyze and compare texts and to do various kinds of computerized literary research. If students themselves cannot create the software they want to use, and if the desired software is not available from commercial sources, a professor can be of great assistance by writing computer programs for students. Fifteen professor-created programs for text analysis are described.Eric Johnson is the author of more than one hundred articles, papers, and monographs about computers, writing, and literature. He is Professor of English and Dean of the College of Liberal Arts at Dakota State University.     

Guidelines for developing educational computer programs

This paper considers the design and production of a CAL or CML package from the point of view of the programmer assisting the teacher who is going to use it. The various stages of production are illustrated by reference to two case studies, the CAMOL (Computer Assisted Management of Learning) system, and CAL packages developed for the Royal Naval College, Greenwich.     

Geostatistics with the Matern semivariogram model: A library of computer programs for inference, kriging and simulation

In many modern applications of geostatistics in the earth sciences, the empirical information is abundant and with complete spatial coverage (e.g. satellite sensor images). In these cases, a critical characteristic of spatial variability is the continuity of the random field that better models the natural phenomenon of interest. Such continuity describes the smoothness of the process at very short distances and is related to the behaviour of the semivariogram near the origin. For this reason, a semivariogram model that is flexible enough to describe the spatial continuity is very convenient for applications. A model that provides such flexibility is the Matern model that controls continuity with a shape parameter. The shape parameter must be larger than zero; a value larger than 1 implies a random field that is m-times mean square differentiable if the shape parameter is larger than m. A package of computer programs is provided for performing the different steps of a geostatistical study using the Matern model and the performance and implementation are illustrated by an example.     

A formal framework for evaluating heuristic programs

We address the question of how one evaluates the usefulness of a heuristic program on a particular input. If theoretical tools do not allow us to decide for every instance whether a particular heuristic is fast enough, might we at least write a simple, fast companion program that makes this decision on some inputs of interest? We call such a companion program a timer for the heuristic. Timers are related to program checkers, as defined by Blum (1993), in the following sense: Checkers are companion programs that check the correctness of the output produced by (unproven but bounded‐time) programs on particular instances; timers, on the other hand, are companion programs that attempt to bound the running time on particular instances of correct programs whose running times have not been fully analyzed. This paper provides a family of definitions that formalize the notion of a timer and some preliminary results that demonstrate the utility of these definitions.     

Make — a program for maintaining computer programs

Good programmers break their projects into a number of pieces, each to be processed or compiled by a different chain of programs. After a set of changes is made, the series of actions that must be taken can be quite complex, and costly errors are frequently made. This paper describes a program that can keep track of the relationships between parts of a program, and issue the commands needed to make the parts consistent after changes are made. Make has been in use on UNIX

1 UNIX is a trademark of Bell Laboratories.

systems since 1975. The underlying idea is quite simple and can be adapted to many other environments.     

A viewdata interface for arbitrary computer programs

The report describes the main algorithms in a computer program for interfacing a viewdata terminal to arbitrary application computer programs, which were not specially written for this terminal. The interface handles the problems of partitioning the input and output to/from the application to suit the small and non-scrolling screen of the viewdata terminal.     

An object-oriented class library for C++ programs

The Object-Oriented Program Support (OOPS) class library is a portable collection of classes similar to those of Smalltalk-80 that has been developed using the C++ programming language under the UNIX operating system. The OOPS library includes generally useful data types, such as String, Date and Time, and most of the Smalltalk-80 collection classes such as OrderedCtn (indexed arrays), LinkedList (singly linked lists), Set (hash tables), and Dictionary (associative arrays). Arbitrarily complex data structures comprised of OOPS and user-defined objects can be stored on disk files or moved between UNIX processes by means of an object I/O facility. The classes Process, Scheduler, Semaphore and SharedQueue provide multiprogramming with coroutines. This paper gives a brief introduction to object-oriented programming and how it is supported by the C+ + programming language. An overview of the OOPS library is also presented, followed by a programming example. The implementation details of two of the class library's more interesting features, object I/O and processes, are described. The paper concludes with a discussion of the differences between the OOPS library and Smalltalk-80 and some observations based on our programming experience with C++ and OOPS.     

一种非接触心电测量方法的研究

目前的心电测量都需要在人体皮肤表面粘贴电极,这种测量方式不便用于日常生活中长时间的心电监测。利用耦合电容原理可以设计一种非接触心电测量方法,该方法通过测量电极与皮肤表面被测量部分形成的耦合电容来检测人体的心电信号,从而避免了粘贴电极,并在后续的心电信号处理过程中,针对本方法采集的心电信号易受干扰的特点,采用了一种自适应主成分分析(PCA)去噪算法。实验表明:这种非接触测量系统可以在不影响被测者正常活动的情况下实现对人体心电信号的长期监测。     

Theory of fault-based predicate testing for computer programs

Predicates appear in both the specification and implementation of a program. One approach to software testing, referred to as predicate testing, is to require certain types of tests for a predicate. In this paper, three fault-based testing criteria are defined for compound predicates, which are predicates with one or more AND/OR operators. BOR (boolean operator) testing requires a set of tests to guarantee the detection of (single or multiple) boolean operator faults, including incorrect AND/OR operators and missing/extra NOT operators. BRO (boolean and relational operator) testing requires a set of tests to guarantee the detection of boolean operator faults and relational operator faults (i.e., incorrect relational operators). BRE (boolean and relational expression) testing requires a set of tests to guarantee the detection of boolean operator faults, relational operator faults, and a type of fault involving arithmetical expressions. It is shown that for a compound predicate with n, n>0, AND/OR operators, at most n+2 constraints are needed for BOR testing and at most 2*n+3 constraints for BRO or BRE testing, where each constraint specifies a restriction on the value of each boolean variable or relational expression in the predicate. Algorithms for generating a minimum set of constraints for BOR, BRO, and BRE testing of a compound predicate are given, and the feasibility problem for the generated constraints is discussed. For boolean expressions that contain multiple occurrences of some boolean variables, how to combine BOR testing with the meaningful impact strategy (Weyuker et al., 1994) is described     

A methodology for evaluating computer integrated manufacturing technologies

The decision to invest in advanced manufacturing technology is often made at the strategic level. The technique to be used to justify these decisions should have the ability to incorporate the non-quantifiable, intangible benefits associated with implementing these technologies. Among the methods introduced recently, the linear additive models have received considerable attention. This paper reviews a linear additive method which can be used to evaluate long-term and short-term automation manufacturing investment alternatives. The paper also concentrates on those cases in which some common characteristics of available alternatives are assumed to be independent.     

Causal reasoning in computer programs for medical diagnosis

Over the last decade substantial advances have been made in the use of causal pathophysiological knowledge in artificial intelligence-based programs for medical diagnosis. Various forms of causal representations have been used. They include probabilistic models, quantitative models, qualitative models, and models that describe causal relations at multiple levels of detail. This paper briefly analyses these methods using three representative systems. Outstanding problems and possible direction in further exploitation of causal reasoning for medical decision-support systems are also discussed.     

ECG variable cine: computer program for presentation of temporal changes in ECG variables over different number of ECG leads

The analysis of exercise electrocardiogram (ECG) is based on the alteration of the measured variables in the detection of coronary artery disease (CAD). In its existing form the analysis of the exercise ECG is laborious and requires much time. The temporal analysis of the ECG variable and the comparison between different phases of the exercise test is difficult and time consuming, especially the simultaneous examination of the variables over several leads. In this article we present a computer program, ECG Variable Cine, for the visualization of the temporal changes of values of exercise ECG variables over the selected ECG lead system. The program includes the stationary 3-D presentation for the variables' alteration simultaneously in all selected leads over the time of exercise test. In addition, the program determines two parameters; the average value of the variable over the selected leads at every sample moment, and the chronotropic index, a parameter that indicates heart rate response to exercise. According to the results the average value of ST-segment deviation at the end of the exercise over the leads and chronotropic index are clinically more competent than the maximum value of ST-segment depression in the detection of CAD.