Conventional text summarization methodologies do not take individual requirements of readers into consideration. In order to generate document summaries that can meet reader requirements, this research develops an automatic document summarization model that generates summaries on the basis of individual requirements of readers. The document summarization problem is transformed into a mathematical problem by analysis of the quality factors for summary and calculation of summary quality indices and constraints of quality factors. The proposed model can be used to properly summarize documents by taking user requirements into consideration. In the near future, a web-based text summarization system will be established in order to evaluate performance of the proposed methodology.