Three-layer graph-based model
The three-layer graph-based model was introduced by Winter in 1995 at the University of Heidelberg . Researchers observed that hospitals increasingly used non-specialized low-cost hardware and many different software systems. The resulting heterogeneity led to a strong demand for integrating all the different systems, and for this purpose the model was designed.
The purpose of the Three-layer Graph-based Model was to support the management hospital IT equipment and to assess its quality. The top layer was the procedural level to describe the functionality of a hospital information system. The middle layer was the logical level, dealing with the application systems and their communication. The lowest level is the physical tool level with the actual hardware and data transmission.
In 2003, a revised version at the University of Leipzig was published: the Revised Three-layer Graph-based Meta Model or 3LGM2. 3LGM2 now understands itself as an ontological basis for modeling a comprehensive information system of a hospital.
The description of the lower two levels remained the same. The top level is now called the domain level consisting of hospital functions and entity types. Between the layers, a lot of relationships exist. The authors developed a graphical tool to create a 3LGM² compliant model for a specific site. This helps to detect shortcomings on the lower two levels.
Three Layer graph based Meta Model 3LGM ² is a Meta Model for the description, planning and evaluation of Information systems. It supports the systematic (strategic) Information management. The three levels are connected by interlevel relations. These essentially express, which application systems support which tasks and on which servers the application systems are installed.
- Winter A, Haux R. A three-level graph-based model for the management of hospital information systems. Methods Inf Med 1995 Sep; 34(4):378-96.
- Winter A, Brigl B, Wendt T. Modeling Hospital Information Systems (Part 1): The Revised Three-layer Graph-based Meta Model 3LGM². Methods Inf Med 2003; 42(5):544-551.
- Three Layer graph based Meta Model. 
- Modeling hospital information systems. Part 1: The revised three-layer graph-based meta model 3LGM2. 
- www.3lgm2.de Project Homepage (in German)
- List of related publications (in English)