The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Joachim Wuttke - One of the best experts on this subject based on the ideXlab platform.

  • Rasch-Modell, suffiziente Statistik, Transformationsgruppen und Methodenkritik: Anmerkungen zu Büchter & Pallack (2012/13) und Vohns (2012)
    Journal für Mathematik-Didaktik, 2014
    Co-Authors: Joachim Wuttke
    Abstract:

    This contribution aims at rectifying some unprecise statements in the debate of Buchter and Pallack (2012, 2013) and Vohns (2012). While Buchter and Pallack (2012) proposed to use the Rasch model to explore implicit standards set by central examinations, Vohns (2012) suggested a tabular analysis. After clarifying the notion of Statistical Sufficiency, both approaches are found to be essentially equivalent, with Vohns’ approach being the simpler one. Buchter and Pallack (2013) postulated that information-reducing statistics must not be analysed without keeping in mind all possible raw data that could yield the same result. This is inadequate when probabilities differ by orders of magnitude, as demonstrated by a counterexample from Statistical physics. Finally, Buchter and Pallack (2013) noted high legitimation pressure when the Rasch model is used to analyse performance data. This requires a bibliographical correction and a more differentiated reassessment: the criticism by Wuttke (2006, preferably 2007) is not directed against heuristic applications of the Rasch model but against a lack of reserve in using results from a model-dependent data analysis when the model does not fit.

  • Rasch-Modell, suffiziente Statistik, Transformationsgruppen und Methodenkritik: Anmerkungen zu Büchter & Pallack (2012/13) und Vohns (2012)
    Journal für Mathematik-Didaktik, 2014
    Co-Authors: Joachim Wuttke
    Abstract:

    Dieser Beitrag soll einige Ungenauigkeiten in der Debatte von Büchter und Pallack (2012 und 2013) und Vohns (2012) richtigstellen. Büchter und Pallack (2012) haben vorgeschlagen, das Rasch-Modell für die inhaltliche Erschließung von Prüfungsanforderungen einzusetzen. Nach Klärung des Begriffs der statistischen Suffizienz stellt sich die von Vohns (2012) vorgeschlagene tabellarische Auswertung als äquivalent und einfacher heraus. Die von Büchter und Pallack (2013) erhobene Forderung, bei informationsreduzierten Statistiken sämtliche mögliche Ausgangsdaten mitzudenken, wird mit einem Gegenbeispiel aus der statistischen Physik zurückgewiesen. Die Bemerkung von Büchter und Pallack (2013) zum Legitimationsdruck bei Verwendung des Rasch-Modells erfordert eine bibliographische Korrektur und inhaltliche Differenzierung; die zitierte Arbeit von Wuttke (2006, besser 2007) richtet sich nicht gegen die heuristische Verwendung des Rasch-Modells, sondern gegen die vorbehaltlose Nutzung modellabhängiger Ergebnisse bei fehlender Modellpassung. This contribution aims at rectifying some unprecise statements in the debate of Büchter and Pallack (2012, 2013) and Vohns (2012). While Büchter and Pallack (2012) proposed to use the Rasch model to explore implicit standards set by central examinations, Vohns (2012) suggested a tabular analysis. After clarifying the notion of Statistical Sufficiency, both approaches are found to be essentially equivalent, with Vohns’ approach being the simpler one. Büchter and Pallack (2013) postulated that information-reducing statistics must not be analysed without keeping in mind all possible raw data that could yield the same result. This is inadequate when probabilities differ by orders of magnitude, as demonstrated by a counterexample from Statistical physics. Finally, Büchter and Pallack (2013) noted high legitimation pressure when the Rasch model is used to analyse performance data. This requires a bibliographical correction and a more differentiated reassessment: the criticism by Wuttke (2006, preferably 2007) is not directed against heuristic applications of the Rasch model but against a lack of reserve in using results from a model-dependent data analysis when the model does not fit.

M. Kaveh - One of the best experts on this subject based on the ideXlab platform.

  • Fisher information matrix of the coherently averaged covariance matrix
    IEEE Transactions on Signal Processing, 1991
    Co-Authors: H.-s. Hung, M. Kaveh
    Abstract:

    Novel expressions are derived for the asymptotic Fisher information matrix which is used to investigate the degree of Statistical Sufficiency of the approximately coherently averaged covariance matrix in the coherent signal-subspace method. These results correct previous ones given by the authors (see Proc. ICASSP-87, Dallas, TX, Apr. 1987). The reasons for the previous erroneous results are discussed.

H.-s. Hung - One of the best experts on this subject based on the ideXlab platform.

  • Robust coherent signal-subspace processing for directions-of-arrival estimation of wideband sources
    IEE Proceedings - Radar Sonar and Navigation, 1994
    Co-Authors: H.-s. Hung
    Abstract:

    The authors propose a class of robust focusing matrices for the coherent signal-subspace method, a novel approach for the estimation of directions-of-arrival of wideband sources. The new class of focusing matrices has robustness against size variations of focusing sectors obtained by preliminary group angle estimates. To quantify information loss due to source focusing, a new measure, termed 'relative efficiency index', is introduced and its properties are proved. This index is then used to assess Statistical Sufficiency of the coherently averaged covariance matrix, a data-reduced statistic on which the coherent signal-subspace method is based. Sensitivity issue as well as estimation performance comparisons for various classes of focusing matrices, based on simulations and relative efficiency index, are also presented.

  • Fisher information matrix of the coherently averaged covariance matrix
    IEEE Transactions on Signal Processing, 1991
    Co-Authors: H.-s. Hung, M. Kaveh
    Abstract:

    Novel expressions are derived for the asymptotic Fisher information matrix which is used to investigate the degree of Statistical Sufficiency of the approximately coherently averaged covariance matrix in the coherent signal-subspace method. These results correct previous ones given by the authors (see Proc. ICASSP-87, Dallas, TX, Apr. 1987). The reasons for the previous erroneous results are discussed.

F. Cappelletti - One of the best experts on this subject based on the ideXlab platform.

  • Information rates of multidimensional front ends for digital storage channels with data-dependent transition noise
    IEEE Transactions on Magnetics, 2006
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    This paper presents a simulation-based method for the computation of the information rates of recently proposed multidimensional front ends for digital storage channels with transition noise. First, we propose an algorithm, based on linear prediction and state reduction techniques, that extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference, and signal-dependent transition noise. Following a previous study on Statistical Sufficiency, we apply this algorithm to compute the information rates of digital storage systems featuring a multidimensional detection front end. The resulting information rates indicate that significant gains may be achievable by multidimensional signal processing techniques in transition-noise-limited digital storage channels

  • ISIT - Information rates of multidimensional front-ends for digital storage channels with data-dependent transition noise
    Proceedings. International Symposium on Information Theory 2005. ISIT 2005., 2005
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    A new simulation-based method to evaluate the information rates of multidimensional front-ends applied to digital storage channels with transition noise is presented. First, we propose an algorithm which extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference and signal-dependent transition noise, by using linear prediction and state reduction techniques. Moreover, following a previous study on Statistical Sufficiency, we extend this algorithm to magnetic channels with a multidimensional front-end. The results suggest that significant gains may be achievable by multidimensional signal processing techniques in transition-noise limited digital storage channels

  • Information rates of multidimensional front-ends for digital storage channels with data-dependent transition noise
    Proceedings. International Symposium on Information Theory 2005. ISIT 2005., 2005
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    A new simulation-based method to evaluate the information rates of multidimensional front-ends applied to digital storage channels with transition noise is presented. First, we propose an algorithm which extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference and signal-dependent transition noise, by using linear prediction and state reduction techniques. Moreover, following a previous study on Statistical Sufficiency, we extend this algorithm to magnetic channels with a multidimensional front-end. The results suggest that significant gains may be achievable by multidimensional signal processing techniques in transition-noise limited digital storage channels

R. Raheli - One of the best experts on this subject based on the ideXlab platform.

  • Linear Predictive Detection for Power Line Communications Impaired by Colored Noise
    EURASIP Journal on Advances in Signal Processing, 2007
    Co-Authors: Riccardo Pighi, R. Raheli
    Abstract:

    Robust detection algorithms capable of mitigating the effects of colored noise are of primary interest in communication systems operating on power line channels. In this paper, we present a sequence detection scheme based on linear prediction to be applied in single-carrier power line communications impaired by colored noise. The presence of colored noise and the need for Statistical Sufficiency requires the design of an optimal front-end stage, whereas the need for a low-complexity solution suggests a more practical suboptimal front-end. The performance of receivers employing both optimal and suboptimal front-ends has been assessed by means of minimum mean square prediction error (MMSPE) analysis and bit-error rate (BER) simulations. We show that the proposed optimal solution improves the BER performance with respect to conventional systems and makes the receiver more robust against colored noise. As case studies, we investigate the performance of the proposed receivers in a low-voltage (LV) power line channel limited by colored background noise and in a high-voltage (HV) power line channel limited by corona noise.

  • Information rates of multidimensional front ends for digital storage channels with data-dependent transition noise
    IEEE Transactions on Magnetics, 2006
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    This paper presents a simulation-based method for the computation of the information rates of recently proposed multidimensional front ends for digital storage channels with transition noise. First, we propose an algorithm, based on linear prediction and state reduction techniques, that extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference, and signal-dependent transition noise. Following a previous study on Statistical Sufficiency, we apply this algorithm to compute the information rates of digital storage systems featuring a multidimensional detection front end. The resulting information rates indicate that significant gains may be achievable by multidimensional signal processing techniques in transition-noise-limited digital storage channels

  • ISIT - Information rates of multidimensional front-ends for digital storage channels with data-dependent transition noise
    Proceedings. International Symposium on Information Theory 2005. ISIT 2005., 2005
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    A new simulation-based method to evaluate the information rates of multidimensional front-ends applied to digital storage channels with transition noise is presented. First, we propose an algorithm which extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference and signal-dependent transition noise, by using linear prediction and state reduction techniques. Moreover, following a previous study on Statistical Sufficiency, we extend this algorithm to magnetic channels with a multidimensional front-end. The results suggest that significant gains may be achievable by multidimensional signal processing techniques in transition-noise limited digital storage channels

  • Information rates of multidimensional front-ends for digital storage channels with data-dependent transition noise
    Proceedings. International Symposium on Information Theory 2005. ISIT 2005., 2005
    Co-Authors: R. Pighi, R. Raheli, F. Cappelletti
    Abstract:

    A new simulation-based method to evaluate the information rates of multidimensional front-ends applied to digital storage channels with transition noise is presented. First, we propose an algorithm which extends recent work on the information rates of magnetic recording channels affected by colored Gaussian thermal noise, intersymbol interference and signal-dependent transition noise, by using linear prediction and state reduction techniques. Moreover, following a previous study on Statistical Sufficiency, we extend this algorithm to magnetic channels with a multidimensional front-end. The results suggest that significant gains may be achievable by multidimensional signal processing techniques in transition-noise limited digital storage channels