The purpose of shipping risk early-warning is that some effective measures are taken to reduce risk probability before the risk brings heavy loss.The shipping risk has the dynamic characteristic,so the key of early-warning is to choice risk early-warning index correctly and evaluate risk grade quantitatively.According to the element extension theory,the rhombus inference model is applied to establish the index system.And the problem of risk grade evaluation can be solved by the assessment model of multi-index performance parameter,which is developed by the extension engineering method.Finally,the main shipping risks and their grades are identified by the example analysis based on the statistical data,which shows the effective and feasible of the shipping risk early-warning method.
The coupled dynamic responses of two pontoons while connecting with each other in irregular waves are calculated by means of 3D potential flow theory. The computation is used to find the optimal status for connecting at certain sea state. On the basis of the relative motion of two pontoons in irregular waves,visual FORTRAN programming language,as well as open graphics library (OpenGL),is used to develop a set of virtual reality system,which is fully interactive and with realistic effect. The transfinite interpolation scheme is applied for the mesh generating of the wave surface,and the wave motion is simulated by surface elevation,which is calculated by 3D potential flow theory.
