Recently I had an interview for a phd in computer science. In the application I was able to choose multiple thematic categories, so I decided to apply for complex event processing, as well as robotics. During the interview I was asked to explain the reasons that I decided to choose these categories. I tried to explain that I am interested in applying AI techniques in data stemming from multiple heterogenous sources and that I believed that both of these categories would give me such an opportunity. Although the methods that I would use to do this as well as the application I would develop would be different for each thematic category. However I believed, that this would not be a problem. The interviewers though seemed dissatisfied with my views though. One of them suggested that I lean more towards the complex event processing thematic category. They asked me then whether I would be interested in applying complex event processing in medical applications (since I have an MSc in Biomedical engineering) or some other area of application such as finance. I replied, that I am more interested in exploring the methodologies involved than the actual application and that both the cases of finance and medical data excite me. However I think that the interviewers were possibly dissatisfied with my answers as I did not seem to come to a closure regarding my decisions. They then replied that a PhD is a process of researching a subject in depth... They also mentioned, that although in my CV I had done several things in the past related to computer science (such as jobs, conference papers and journals) they all were quite different from each other. This could possibly indicate that I was more interested in learning several things instead of giving special emphasis in one area... I replied to this by saying that the fact that I took advanage of some opportunities in the past did not necesserily mean I would not be willing and motivated enough in researching a subject for a long time.
However I feel dissatisfied with the responses I gave in this interview. The reason is that I realised that if I had a gun pointed at my head in order to choose a topic, I would choose the application of complex event processing in finance data. So I want to ask the following:
I am able to talk to one of my interviewers. Would it be a good idea to tell him that I realised that if had to choose only one thing, that would be the application of complex event processing in finance data and I would forget about robotics or the medical modality as they only seem nice alternatives (with the exact words described above). (I have no previous experience though in these areas ... but I feel really motivated in researching this topic)