Wyniki wyszukiwania - BazTech

1

On the mathematical theory of evidence in navigation

Filipowicz W.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

|

2016

|

nr 45 (117)

159--167

EN

In most problems encountered in navigation, imprecision and uncertainty dominate. Methods of their processing rely on rather obsolete formalisms based on probability and statistics. Available solutions exploit a limited amount of available data, and knowledge is necessary to interpret the achieved results. Profound a posteriori analysis is rather limited; thus, the informative context of solutions is rather poor. Including knowledge in a nautical data processing scheme is impossible. Remaining stuck with the traditional formal apparatus, based on probability theory, one cannot improve the informative context of obtained results. Traditional approaches toward solving problems require assumptions imposed by the probabilistic model that exclude possibility of modelling uncertainty. It should be noticed that the flexibility of exploited formalism decide the quality of upgrading models and, subsequently, on the universality of the final results. Therefore, extension of the available formalisms is a challenge to be met. Many publications devoted to the mathematical theory of evidence (MTE) and its adaptation for nautical science in order to support decision making in navigational processes have enabled one to submit and defend the following proposition. Many practical problems related to navigational ship conducting and to feature uncertainty can be solved with MTE; the informative context of the obtained results is richer when compared to those acquired by traditional methods. Additionally, a posteriori analysis is an inherent feature of the new foundations. The brief characteristics of a series of publications devoted to the new methodology are the main topics of this paper.

2

Position fixing and its accuracy evaluation

Filipowicz W.

Zeszyty Naukowe / Akademia Morska w Szczecinie

|

2013

|

nr 36 (108) z. 1

42--48

EN

In traditional approach to position fixing navigator exploits mathematical apparatus based on probability theory. Series of assumptions are required in order to use the platform to draw final conclusions. Limited ability is available regarding fix accuracy a posteriori evaluation. In the paper Mathematical Theory of Evidence is exploited in order to introduce new foundations enabling modeling and solving problems with uncertainty. Modified scheme of approach towards making the fix delivers new standpoint for perceiving accuracy of the result.

3

Evidence Representations in Position Fixing

Filipowicz W.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 10b

256-260

EN

Uncertain data are used in navigation, thanks to the nautical knowledge position is then fixed and evaluated. Data processing is rather limited since traditional mathematical apparatus based on probability theory with necessary assumptions is not flexible enough to include knowledge and ignorance into position fixing calculation scheme. Limited possibility is available regarding fix accuracy evaluation. In the paper possibilistic extension of Mathematical Theory of Evidence is explored as new platform enabling modeling and solving problems with uncertainty.

PL

Niepewne dane są używane w nawigacji, na ich podstawie, dzięki nautycznej wiedzy, pozycja obserwowana jest określana i oceniana. Przetwarzanie danych wejściowych jest raczej ograniczone głównie z powodu ograniczeń tradycyjnie wykorzystywanego aparatu matematycznego. Aparat taki, oparty na podejściu probabilistycznym, narzuca szereg uwarunkowań, a jego elastyczność nie pozwala na uwzględnienie wiedzy jak i ignorancji. W artykule posybilistyczne rozszerzenie Matematycznej Teorii jest przedmiotem eksploracji, jako nowa platforma umożliwiająca modelowanie i rozwiązywania zadań z niepewnością.

4

Fuzzy Evidence in Terrestrial Navigation

Filipowicz W.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

|

2011

|

Vol. 5, no. 2

225--232

EN

Measurements taken in terrestrial navigation are random values. Mean errors are within certain ranges what means imprecision in their estimation. Measurements taken to different landmarks can be subjec-tively diversified. Measurements errors affect isolines deflections. The type of the relation: observation error – line of position deflection, depends on isolines gradients. All the mentioned factors contribute to an overall evidence to be considered once vessel’s position is being fixed. Traditional approach is limited in its ability of considering mentioned factors while making a fix. In order to include evidence into a calculation scheme one has to engage new ideas and methods. Mathematical Theory of Evidence extended for fuzzy environment proved to be universal platform for wide variety of new solutions in navigation.

5

New Approach Towards Position Fixing

Filipowicz W.

Annual of Navigation

|

2010

|

No. 16

41-53

EN

Navigation aids indications, measured distances and bearings are random values governed by various distributions, normal characteristic is widely assumed. Navigation handbooks read that mean error of bearing taken with radar is within a given range, distance error is within certain percentage of an obtained value. It is also known that measurements taken to different landmarks can be subjectively evaluated therefore diversified. All the mentioned factors are to be taken into account once vessel position is being fixed. In order to include them into a calculation scheme one has to engage new ideas and use different approaches. Mathematical Theory of Evidence extended for fuzzy environment proved to be universal platform for wide variety of new solutions in navigation.