The National Information Exchange Model (NIEM) is rapidly becoming the most important XML exchange standard for the U.S. government and its information partners. This article by Priscilla Walmsley, a four-part series, provides an overview of the process for defining a NIEM information exchange. It then takes one through the first step—modeling an exchange using UML, through the last step - assembling the schemas, documentation, and all the other artifacts of an exchange into a complete NIEM-conformant IEPD. The last article in these series, also describes the process of validating and publishing an IEPD.
For more details on this, please click on the links below:
Part 1 - Model your NIEM exchange
Part 2 - Map and subset NIEM
Part 3 - Extend NIEM
Part 4 - Assemble the IEPD
Source: Creating a NIEM IEPD