During object-relational database physical structure design, problems are caused by three factors: ambiguity of transformations of conceptual model, multiplicity of quality assessment criteria, and a lack of constructive model. In the present study a constructive hierarchical model of physical database structure has been developed. Implementations are used in XML, SQL and Java languages. Multi-criterial structure optimisation method has also been developed. Structure variation space is generated using transformation rule database. Prototype has been implemented within the framework of the research.
Algorithm for searching out similar ships within expert system of computer aided preliminary design of ship power plant
This paper presents an algorithm for searching out similar ships, implemented in a hybrid system for aiding preliminary design of ship power plant, based on new similarity functions as well as those adapted from literature sources. For searching out similar ships a multicriterial optimization method of weighed profits was applied.
On the modeling of car passenger ferryship design parameters with respect to selected sea-keeping qualities and additional resistance in waves
This paper presents the modeling of car passenger ferryship design parameters with respect to such design criteria as selected sea-keeping qualities and additional resistance in waves. In the first part of the investigations approximations of selected statistical parameters of design criteria of ferryship were elaborated with respect to ship design parameters. The approximation functions were obtained with the use of artificial neural networks. In the second part of the investigations design solutions were searched for by applying the singleand multi-criterial optimization methods. The multi-criterial optimization was performed by using Pareto method. Such approach made it possible to present solutions in such form as to allow decision makers (shipowner, designer) to select solutions the most favourable in each individual case.