What is the best way to start a book?
Many people will tell you that the best way is to gather experience and then write your book. Others will tell you to write as you gather experience. Truth is..... I do not know yet who is right. While it is true that a lot of great books are written after experience has been learn, it is also true that a lot of great books are written on the go.
So how does this translates to papers in Machine Learning?
For most graduate programs, you'll need to write Conference and Journal papers. In some universities, though, they are not really picky on which journals or conferences, as long as it's published. Others, do care to which conference do you go. Not to mention that your Professor probably has already a set of conferences where he is a regular, thus, asking you to write a paper for such conferences.
So, back to the basic question, do you write as you go, or do you write once you finished every experiment, theory and survey? (at the end of your PhD). Some people will tell you the former is the better, while others, will tell you that is good to have a ton of papers, since most committees will rarely look at the papers themselves, but just at the sheer number of publications.
I think a fair balance is the best policy, you do have to wait until you have good results to publish, but you also have to publish enough so you get to go to different conferences and get feedback from experts in the area you are working in, or at least a good networking. Be careful to remember that really good journal or conferences won't accept papers of half-done research or quick baked results.
Remember, though, that most journals will take their sweet long time to accept your paper, or even reject it. So, if you wait until the end to submit it, you'll definitively will have troubles getting your paper accepted by the end of your PhD. (We are speaking that some IEEE journals take around 7 to 8 months to give you any feedback)
Lastly and most important, when in Rome, do as Romans do. Regardless on your opinion, truth is, you are a simple student. Thus, if you prefer to wait, and your committee wants you to publish.....you'll either publish or go. On the other hand, if the University wants you to go to specific conferences (acceptance rates around 20 or 30 %), you will have to wait, even if you badly want to publish any incremental gain you''ve had.
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