The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform

Wenjune Wang - One of the best experts on this subject based on the ideXlab platform.

  • qrs complexes detection for ecg signal the Difference Operation method
    Computer Methods and Programs in Biomedicine, 2008
    Co-Authors: Yunchi Yeh, Wenjune Wang
    Abstract:

    This paper proposes a simple and reliable method termed the Difference Operation Method (DOM) to detect the QRS complex of an electrocardiogram (ECG) signal. The proposed DOM includes two stages. The first stage is to find the point R by applying the Difference equation Operation to an ECG signal. The second stage looks for the points Q and S based on the point R to find the QRS complex. From the QRS complex, the T wave and P wave can be obtained by the existing methods. Some records (QRS complex and T and P waves) of ECG signals in MIT-BIH arrhythmia database is tested to show the DOM has a much more precise detection rate and faster speed than other methods.

Francois Picalausa - One of the best experts on this subject based on the ideXlab platform.

  • on the satisfiability problem for sparql patterns
    Journal of Artificial Intelligence Research, 2016
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL 1.0 patterns is undecidable in general, since the relational algebra can be emulated using such patterns. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is decidable by syntactic checks on bound variables and on the use of literals. Although the problem is shown to be NP-complete, it is experimentally shown that the checks can be implemented efficiently in practice. The paper also points out that satisfiability for the so-called 'well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.

  • on the satisfiability problem for sparql patterns
    arXiv: Databases, 2014
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL patterns is undecidable in general, since the expressive power of SPARQL 1.0 is comparable with that of the relational algebra. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is efficiently decidable by simple checks on bound variables and on the use of literals. The paper also points out that satisfiability for the so-called `well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.

Yunchi Yeh - One of the best experts on this subject based on the ideXlab platform.

  • qrs complexes detection for ecg signal the Difference Operation method
    Computer Methods and Programs in Biomedicine, 2008
    Co-Authors: Yunchi Yeh, Wenjune Wang
    Abstract:

    This paper proposes a simple and reliable method termed the Difference Operation Method (DOM) to detect the QRS complex of an electrocardiogram (ECG) signal. The proposed DOM includes two stages. The first stage is to find the point R by applying the Difference equation Operation to an ECG signal. The second stage looks for the points Q and S based on the point R to find the QRS complex. From the QRS complex, the T wave and P wave can be obtained by the existing methods. Some records (QRS complex and T and P waves) of ECG signals in MIT-BIH arrhythmia database is tested to show the DOM has a much more precise detection rate and faster speed than other methods.

Xiaowang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • on the satisfiability problem for sparql patterns
    Journal of Artificial Intelligence Research, 2016
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL 1.0 patterns is undecidable in general, since the relational algebra can be emulated using such patterns. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is decidable by syntactic checks on bound variables and on the use of literals. Although the problem is shown to be NP-complete, it is experimentally shown that the checks can be implemented efficiently in practice. The paper also points out that satisfiability for the so-called 'well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.

  • on the satisfiability problem for sparql patterns
    arXiv: Databases, 2014
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL patterns is undecidable in general, since the expressive power of SPARQL 1.0 is comparable with that of the relational algebra. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is efficiently decidable by simple checks on bound variables and on the use of literals. The paper also points out that satisfiability for the so-called `well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.

Jan Van Den Bussche - One of the best experts on this subject based on the ideXlab platform.

  • on the satisfiability problem for sparql patterns
    Journal of Artificial Intelligence Research, 2016
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL 1.0 patterns is undecidable in general, since the relational algebra can be emulated using such patterns. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is decidable by syntactic checks on bound variables and on the use of literals. Although the problem is shown to be NP-complete, it is experimentally shown that the checks can be implemented efficiently in practice. The paper also points out that satisfiability for the so-called 'well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.

  • on the satisfiability problem for sparql patterns
    arXiv: Databases, 2014
    Co-Authors: Xiaowang Zhang, Jan Van Den Bussche, Francois Picalausa
    Abstract:

    The satisfiability problem for SPARQL patterns is undecidable in general, since the expressive power of SPARQL 1.0 is comparable with that of the relational algebra. The goal of this paper is to delineate the boundary of decidability of satisfiability in terms of the constraints allowed in filter conditions. The classes of constraints considered are bound-constraints, negated bound-constraints, equalities, nonequalities, constant-equalities, and constant-nonequalities. The main result of the paper can be summarized by saying that, as soon as inconsistent filter conditions can be formed, satisfiability is undecidable. The key insight in each case is to find a way to emulate the set Difference Operation. Undecidability can then be obtained from a known undecidability result for the algebra of binary relations with union, composition, and set Difference. When no inconsistent filter conditions can be formed, satisfiability is efficiently decidable by simple checks on bound variables and on the use of literals. The paper also points out that satisfiability for the so-called `well-designed' patterns can be decided by a check on bound variables and a check for inconsistent filter conditions.