Identifying assumptions in a research article Sorry if this is a very basic question but I have to clear my head. 

When reading a research article, how can I identify the assumptions it makes? Can I "assume" any non referred part/sentence to be an assumption by the author? For example, if an article in the field of computer science states in the normal flow of the discussion that "micro-controllers have become the bedrock of automation systems" OR "open source operating systems are more secure than propriety operating systems", but the author does not refer to any source for his/her claims, Can I consider these sentences to be "assumptions" by the writer? 

Am I right? If not, can anyone explain it to me?

The other question is that whether stating a universal truth should be considered as an assumption by the writer? e.g. "mobile phones have communications easier and more reliable".      

Cheers
There is no clear way to distinguish hidden assumptions, but let's discuss your example (I'm unfamiliar with the field): 


  open source operating systems are more secure than propriety operating systems


Some possibilities:


The author makes an assumption here. It can be, e.g., based on their personal experience, or justified by some common sense.
The community makes an assumption. This may be a generally accepted assumption, but nobody has actually done research on it.
This is a generalization / rule of thumb which usually holds true.
This is a well known fact, so old or trivial that nobody bothers to cite it anymore.


I usually consider all nontrivial statements as assumptions/hypotheses/conjectures unless I find evidence to the contrary.