Development of Bayesian Decision Making System for Ship Navigation

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The main objective of this research work is development of a simple decision making system for merchant ships. In the system, the ship's hull is recognized as a wave probe and the ship motion data are used for the estimation of sea states and calculation of the several ship responses as the information for the navigation. The head investigator has already achieved at the basic research work of the Bayesian estimation of the directional wave spectrum using the ship motion data. In 1999, therefore, the following results could be obtained by this research project :(1) Making up the hardware : Using the FOG (Fiver Optic Gyroscope) system, the hardware by which the ship motion data signal can be imported through the"COM port"of personal computer systems was made for general purpose.(2) Improvement of the algorithm : Bayesian estimation algorithm for the estimation of wave spectrum was modified for improvement of computational efficiency.(3) Development of the application software : The appl … More ication software that can store ten minutes length time history data every one hour was developed. Microsoft Visual C++ was selected as the computer language for the adaptability to the Windows OS.(4) On board tests : In November 1999 and March 2000, three on board tests were carried out using the training ship Shiojimaru and the application program was revised.Based on the above-mentioned results, the following research work were performed.(1) Installation and functional test : The developed system was installed on the bulk carrier on the line between Japan and Australia. The functional test was continued around a half year and bugs were found and fixed in the application program, the system was tested under the automatic operation(2) Acquisition of the ship motion data in actual voyages :In the later half of the functional test, the system was operated automatically during several voyages and the measured data were stored in the hard disk of the notebook computer. The application program was modified to have the functions of not only storage of the ten minutes time history data but also creations of the statistical summary CSV file. Therefore the out-lines of the voyages are easily grasped.(3) Making of the reportThe report of this research will be made just as planned.As the problem transferred form the last fiscal year, the algorithm of the Bayesian estimation should be modified for on-line calculation. The present system is now equipped on the container ship operated on the north pacific line and the measurement is continued. Less