The working conference dealt with recent developments in thefield of modelling and optimization and with knowledge baseddecision support systems. This contributed to the realiza-tion of the aims of the working group 7.6 which are: - topromote theoretical research in the field of optimizationincluding mathematical programming and optimal control; -toencourage the development of sophisticated knowledge basedsystems in which refined optimization models and algorithmsare used; - to contribute to the exchange and disseminationof information and collective experience among the inter-ested groups and individuals; - to support the practical ap-plication of such systems in control, engineering, industry,economy etc.A selection of papers is included into this proceedings vo-lume since they reflect the current state of research inareas of interest to the field of (KB)DDS, and/or they arethe value for the dissemination and exchange of informationrelated to research topicsof interest, and/or they describerelevant practical experience related to designing, buil-ding, implementing and using (KB)DSS.