Transplantable immunoglobulin-secreting tumors in rats. VI. N-terminal sequence variability in LOU/C/Wsl rat monoclonal heavy chains.

Abstract

Parametric roll is one of the research topics in the maritime industry. Due to longitudinal\nwaves, this phenomenon will cause explosive increase in a ships roll motion.\nThis large roll oscillations may lead to dangerous situations for the ship,\ncargo, crew and passengers. It can even lead to capsizing of the ship and results\nin damages into millions of Euro’s. Therefore parametric roll in ships need to be\navoided.\nTo determine if an avoidance system needs to be activated, nowadays the roll angle\nof the ship is measured. When this angle exceeds a certain value, the avoidance\nsystem will be switched on. If this occurs the ship already has a quite large roll angle.\nParametric roll occurs under different conditions of the environment and ship.\nOne of these conditions is that the natural roll period of the ship is twice the period\nof the waves observed from the ship (encounter frequency). So if the encounter\nfrequency can be estimated, it also can be predicted when parametric roll appears.\nFirst a small literature study to parametric roll is done. Then, in order to "‘detune"’\nthe roll condition, a dynamical speed controller is described. As a result of\nthat a surge-roll model is considered. After that, the encounter frequency is estimated\nby using an identification algorithm that combines the least square method\nwith a matrix forgetting factor algorithm. The model is further implemented in an\nelectro mechanical system in order to experimentally validate the effectiveness of\nthe controller.\nThe method to estimate the encounter frequency did not work out as expected.\nYet the proposed estimation algorithm wasn’t suitable, the average of the estimated\n!e signal seemed to variate around the expected value. On the other hand the dynamic\nvelocity controller was tested in the experimental setup. The controller now\nwasn’t activated when the encounter frequency reached a critical level, but at a critical\nroll angle of the ship. Slowing down the ship seemed to be a possibility to avoid\nparametric roll. But there the question occurs if one wants to take into account the\neconomic disadvantages of nearly coming to stand still. More research to combine\nspeed adjustment and avoidance mechanisms need to be done.