I have downloaded an article from Dzone regarding Test Design Automation. I"m not quite understand what is Test Design Automation.
Please enlighten me on this.
Test Design Automation is exactly that - writing your tests in a way that can immediately be used for automation.
I think you're talking about this five page article on test design automation. The article goes off on a few (potentially unnecessary) tangents, but it's all in there.
It's best summarised at the beginning of Chapter 2, which says:
As more and more organizations adopt test-driven, agile development methods, they gravitate towards test design automation — practices and technology that help test teams automatically generate reusable test assets like test cases, test data, and test automation scripts right from clearly defined and complete requirements.
and halfway through Chapter 5:
Test design automation can help you break the barriers to testing at the speed of agile, while helping you focus on improving quality, collaboration, speed, and efficiency.
The image in Chapter 2 is also quite useful (in context), but re-read the whole page first to make sure you understand the concept... otherwise it doesn't make much sense:
This is the closest to Test Design Automation I could think of, you define the rules and overall design and let the code do the rest