In this talk we will present our work on a framework towards the modeling of 
Extract-Transform-Load (ETL) processes and the optimization of ETL workflows.  
The goal of this research was to facilitate, manage and optimize the design 
and implementation of the ETL processes both during the initial design and 
deployment stage and during the continuous evolution of a data warehouse. 

In particular we will present our results which include:

	The provision of a novel conceptual model for the tracing of 
inter-attribute relationships and the respective ETL transformations in the 
early stages of a data warehouse project along with a methodology for 
its construction.

	The provision of a novel logical model for the representation of 
ETL processes with two main characteristics: genericity and customization.

	The presentation of a methodology for the semi-automatic transition 
from the conceptual to the logical model for ETL processes.

	An attempt to use ontology-based mechanisms to semi-automatically 
capture the semantics and the relationships among the various sources.

	The tuning of an ETL workflow through several algorithms for the 
optimization of the execution order of the activities.

Finally, we will discuss some issues on future work in the area that we 
consider important and a step towards the incorporation of the above 
research results to other areas as well.