Diploma Thesis from the year 2007 in the subject Computer Science - Software, grade: 1, Dresden Technical University, language: English, abstract: Design patterns have proven to be important building blocks and means of reuse in software design. However, the mere number of available design patterns complicates the decision-making which design pattern to choose and demands tools assisting in this process. We hence propose a knowledge-based formal representation of design patterns, a representation that is accessible by tools. Existing approaches to formalizing design patterns generally cover solely the formal description of the structure of design patterns. However, an important part of a design pattern description is the intent section, because the intent describes what the design pattern does and which design problems a pattern addresses. In this work, we develop a novel approach of formalizing design patterns by their intent. The formal representation is based on OWL, the web ontology language. The developed ontology can serve as support for the decision-making of choosing the right design pattern. We furthermore develop a tool that uses the ontology as a knowledge-base. The tool allows the user to visually describe design problems and gives suggestions of design patterns that solve a given design problem.