- 1-development of an imputation strategy for the portal adus

The PORTAL ADUS stores traffic data reported by sensor station deployed along the freeway system of the Portland, Oregon metropolitan area. In addition to data retrieval interfaces, PORTAL provides end user applications such as congestion maps. The utility of end user applications is subject to the availability of data. Traffic data is generally known to suffer from a variety of problems, including incomplete observations. An application such as a congestion map is highly sensitive to data quality – in particular, the map is unable to display information if data is not available. Motivated by end-user applications, the PORTAL project has looked at imputation techniques for deployment in the archive, in an attempt to support on-line and off-line needs. PORTAL’s imputation strategy consists of carefully selecting a few imputation methods, in addition to implementing an imputation management mechanism.