Emmanuel Skordalakis

Syntactic pattern recognition of the ECG

An application of the syntactic method to electrocardiogram (ECG) pattern recognition and parameter measurement is presented. Solutions to the related problems of primitive pattern selection, primitive pattern extraction, linguistic representation, and pattern grammar formulation are given. Attribute grammars are used as the model for the pattern grammar because of their descriptive power, founded upon their ability to handle syntactic as well as semantic information. This approach has been implemented and the performance of the resultant system has been evaluated using an annotated standard ECG library. >

Syntactic ECG processing: a review

Abstract The work which has been made so far in the field of syntactic electrocardiogram (ECG) processing is reviewed in this paper. Although syntactic methods seem suitable to the analysis of waveforms, not much progress has been made in the area of ECG waveforms. The reasons for this are given together with directions on how the difficulties could be overcome.

An attribute grammar for QRS detection

Abstract In automatic electrocardiogram (ECG) processing the detection of the QRS complexes is of fundamental importance. Many algorithms have been developed for this purpose. These algorithms are divided into three categories: (1) non-syntactic (2) syntactic and (3) hybrid. A syntactic algorithm, described by an attribute grammar, is presented in this paper.

A novel family of compression algorithms for ECG and other semiperiodical, one-dimensional, biomedical signals

In this paper, a novel family of compression algorithms is presented, which is designed to exploit the redundancy of one-dimensional (1-D) semiperiodical biomedical signals resulting from the cyclic nature of the underlying physical process. The basic idea is that a pool of past-seen cycles is maintained and cycles to be encoded can be stored as transformed versions of those residing in the pool. Conceptually, this approach is an extension of dictionary-based coding schemes used for text compression to signal patterns residing in an n-dimensional space. A cycle transformation method is introduced in order to render the pattern matching process practical and to enable cycle substitution. Based on the principles of the algorithmic family and this transformation method, an electrocardiogram (ECG) oriented algorithm is implemented and thoroughly tested. The performance of this implementation is examined theoretically and deductions about the optimal algorithm settings are made. The ECG compression algorithm is superior to the average beat subtraction algorithm as proposed by Hamilton and Tompkins (1991) in cases where high compression ratios are required.

Rule-based systems and pattern recognition

Abstract It is shown in this paper that the rule-based approach to pattern recognition is very similar to the hybrid one i.e. the approach that combines the statical and the syntactic approach. Moreover, an attribute grammar evaluator is proposed which can be used as a common base for these approaches to pattern recognition.

Recognition of the Shape of the ST Segment in ECG Waveforms

A method which recognizes the shape of the ST segment is presented in this paper. This method when applied to an ST segment gives as results: 1) the onset and the end of the ST segment and 2) the equation of a straight line or of a parabola that best approximates this ST segment.

Web-based teaching in software engineering

Abstract The introduction of the new technologies of computer networks and hypermedia systems in education seems promising. However, only through experimentation can the effectiveness of these technologies be demonstrated. This was the main objective of the EONT project, in the process of which the National Technical University of Athens adapted an introductory course in Software Engineering to a novel enriched instructional delivery mode. The existing course material was supplemented by Web-based courseware, integrated into a Web-based novel networked learning environment. In this article we report on the results of our research and development, concerning this particular course, and discuss the results that were obtained from our evaluation study.

CADMOS: an approach to developing Web-based instructional systems

The educational use of the Internet and the World Wide Web has grown enormously over the last few years and continues to grow at a tremendous rate. Instructional systems, based on these networked technologies, have been constructed to solve instructional problems. There is evidence that these systems efficiently support the instructional process. Instructional developers should follow effective and quality driven development methodologies, which are specifically developed to support the development of network-based instructional systems. This article presents a methodology, CADMOS, which accords to the principles of the third and partially the fourth generation of Instructional Systems Development (ISD). The main innovation of CADMOS is its advocacy on splitting an instructional system into four sub-systems: human, webware, other learning resources, and specific infrastructure sub-systems.

A Model of Collaborating Agents for Content-Based Electronic Document Filtering

The huge volume of distributed information that is nowadays available in electronic multimedia documents forces a lot of people to consume a significant percentage of their time looking for documents that contain information useful to them. The filtering of electronic documents seems hard to automate, partly because of document heterogeneity, but mainly because it is difficult to train computers to have an understanding of the contents of these documents and make decisions based on user-subjective criteria. In this paper, we suggest a model for the automation of content-based electronic document filtering, supporting multimedia documents in a wide variety of forms. The model is based on multi-agent technology and utilizes an adaptive knowledge base organized as a set of logical rules. Implementations of the model using the client-server architecture should be able to efficiently access documents distributed over an intranet or the Internet.

Morphological hand-printed character recognition by a skeleton-matching algorithm

We study the use of mathematical morphology for handprinted character recognition. Our approach uses the morphological skeleton transform as the shape descriptor. An efficient skeletonmatching algorithm, which renders the similarity between two skeletons as a distance measure, is employed. Based on this distance measure, a character is classified by a minimum distance classifier. The morphological skeleton transform contains complete shape information and is shown as a powerful descriptor for this class of shapes. We also study the pattern spectrum as a shape descriptor for hand-printed characters. However, the pattern spectrum conveys only information about the shape/size distribution of a given object, which turns out to be not very efficient for hand-printed characters. Experimental results demonstrate the efficiency of the skeletonbased approach and the inadequacy of the pattern-spectrum-based approach.