K-distribution

About: K-distribution is a research topic. Over the lifetime, 1281 publications have been published within this topic receiving 51774 citations.

Comments on the Neyman and Beall Formulas for `Contagious' Type-A Probability Distributions Applied to Burst Processes Especially in the Field of Digital Transmission

Abstract: Various CCITT activities initiated since the late seventies and recent publications on research intended to assess the quality of communication channels transmitting digital information have shown that, although further studies are necessary, Neyman's 'contagious' typeprobability distribution-briefly termed NCDA-seems to be an appropriate tool for the mathematical-statistical description of the error performance of such transmission paths on which disturbances frequently give rise to error bursts. Since the NCDA, developed as early as 1939 for the description of certain experimental results obtained in the field of botany, cannot be assumed to be generally known to communication engineers, this report is intended to give some explanations and historical background information mainly based on Neyman's original paper [1] and n on-communication-engineering publications. Moreover, aspects of the computer implementation are discussed for the application of the NCDA. With respect to the problem of the numerical NCDA calculation, attention shall be paid to a recurrence algorithm developed by Beall which-in contrast with the application of Neyman's original probability formula-allows such calculations to be carried out exactly without approximative constraints. Übersicht: Eine Reihe von CCITT-Aktivitäten seit Ende der siebziger Jahre sowie Publikationen aus jüngster Zeit im Zusammenhang mit Untersuchungen über mögliche Qualitätsaussagen für Übertragungswege digitaler Informationen zeigen, daß zur mathematisch statistischen Beschreibung des Fehlerverhaltens dieser Übertragungswege, auf denen sich Störungen oft in Fehlcrbündeln auswirken, die Neyman'sche .ansteckende' Wahrscheinlichkeitsverteilung vom Typ A kurz: NCDA ein geeignetes Mittel zu sein scheint, wenngleich weitere Untersuchungen notwendig sind. Da die NCDA, bereits 1939 für die Beschreibung gewisser Versuchsergebnisse auf dem Gebiet der Botanik entwickelt, in der Nachrichtenübertragungstechnik nicht als allgemein bekannt unterstellt werden darf, ist mit der vorliegenden Arbeit beabsichtigt, einige Erläuterungen und historische Hintergrundinformationen zu geben, die sich im wesentlichen auf die Neyman'sche Originalarbeit [1] sowie auf nicht-nachrichtentechnische Publikationen stützen. Außerdem werden bezüglich der Anwendung der NCDA Aspekte der Rechner-Implementierung diskutiert. Dabei soll zur Frage der numerischen NCDA-Berechnung das Augenmerk auf einen Rekursionsalgorithmus von Bcall gelenkt werden, mit dem derartige Berechnungen im Gegensatz zur Anwendung der originären Neyman'schen Wahrscheinlichkeitsformel exakt ohne approximative Nebenbedingungen durchgeführt werden können. Für die Dokumentation: Mathematische Statistik / Ansteckende Wahrscheinlichkeit / NEYMAN'sche Wahrscheinlichkeitsverteilung / BEALL'scher Rekursionsalgorithmus / Digital-Nachrichtenübertragung / Nachrichtenkanal / Kanalqualität

A Numerical Integral Algorithm Based on the CAPSO to Improve the Estimation for the Parameters of the Homodyned-K Distribution

Abstract: The homodyned-K (HK) distribution is a widely used statistical model, whose parameters have different physical-meanings for tissue characterization. In the present study, the maximum likelihood estimation (MLE) method based on the Newton-Raphson algorithm is proposed to estimate the HK parameters solely. For improving the accuracy and convergence of the MLE, the cloud adaptive particle swarm optimization (CAPSO) algorithm is proposed for the integral calculation of the probability density function (PDF) of the HK distribution. In the experiments, sets of samples satisfying the HK distribution are generated, and then the parameters are estimated by the proposed CAPSO-based MLE method. The statistics of estimation errors are calculated, and compared with the results based on the mean intensity and X- and U-statistics (XU) method, which is the latest one based on moment estimation. Experimental results show that the proposed method can solely estimate the HK parameters with a small error level, which means a further practical value in ultrasonic applications.

The application of the principle of minimum cross-entropy to the characterization of the exponential-type probability distributions

Abstract: Systematic and simple characterizations are presented for several familiar distributions in exponential family by means of the principle of minimum cross-entropy (minimum discrimination information). The suitable prior distributions and the appropriate constraints on expected values are given for the underlying distributions.

Simulation of Arbitrary Gamma Distributions

Abstract: Two simulation procedures for arbitrary gamma distributions are compared. Both procedures depend on closed form approximations to the cumulative gamma distributions, but one procedure appears to yield considerably more accurate results than the other. Tables are given which allow this procedure to be easily applied.