MADS stands for “Missing in ADS.” Every astronomer, I believe, knows what ADS is. As we have [EotW] series and used to have [ArXiv] series, creating a new series for semi-periodic postings under the well known name ADS seems interesting.

I’m not sure about these days, but when I was studying astronomy a decade ago, ADS was Google in astronomy. Once switching to statistics, I was shocked at the fact that there was no composite search engine for statistical literature and databases. I showed ADS to fellow statistics students how good this is at that time and compared ADS with what are available in statistics: JSTOR only had 5 year and older materials. Citeseer was not born nor Project Euclid. Google scholar was not thinkable at all. I used to dig the library cd-roms to satisfy my craving for more information. Now those days are over thanks to Google and other scientific search engines. Yet, astronomers prefer ADS than any other database and search engines because of its comprehensiveness.

Let’s stop praising ADS here and focus on [MADS]. The key of [MADS] is to introduce something common and popular in other fields that does not appear in ADS. Believe it or not, sometimes I encounter missing elements, most likely jargon of other fields, from this giant and old (mature) data system. For example, HMM is one although more will come in the series. HMM stands for Hidden Markov Model. When you put “Hidden Markov Model” as keywords in your search among referred astronomical journals[1], you’ll see no result within astronomical publications.

Then, what is Hidden Markov Model? I’d rather defer my answer to wiki:Hidden Markov Model, references therein, and image/signal processing text books (I learned the term from a undergraduate text book about a decade ago. So HMM must be a very common and well received methodology). Since astronomers handle images and signals so often, I thought HMM might be a useful tool for modeling and analyzing astronomical data some years back. Unfortunately, it hasn’t emerged yet.

Finding a MADS does not provide me an eureka moment. It only makes me wish that this MADS appears soon in ADS. One of you soon will be the first person who adopts HMM in your research and will be cited as a pioneer within the astronomy community.

Well, against all this hope, I might be forced to drop this post if someone finds out HMM is already described in published astronomy papers while he/she teaches me how to search ADS better in secret.

  1. Otherwise, ADS search all arxiv papers, which include all computer science, math, statistics, physics, and more[]
  1. mauro:

    try the fulltext search
    (tip enable: Select from Article pages only)
    you can found some references to the HMM

    12-08-2008, 4:54 pm
  2. hlee:

    Thanks! It does work.:) TomLoredo also gave me some tips and related papers (not referring HMM, since such papers seem quite rare). Those search results will lead some interesting postings in future. I have quite many groups of words algorithm-wise that I couldn’t find from ADS but available from other journals “frequently.” The point is dragging attentions, bringing in discussions related to those terms, and connecting methodologies from other disciplines to astronomy wherever the measure of intersection is not zero. And I do appreciate your attention toward my MADS and advice.

    Disclaimer: Statistically, missing does not necessarily mean “completely missing.” “Partially missing” also counts. Please, do fault finding that you are able to find references to the terms that I claim MADS. I strongly encourage you to do so. It’ll not offend me at all but make me feel rewarded.

    12-08-2008, 7:11 pm
  3. mauro:

    I’m not sure to understand what you exactly mean with “do fault finding…”, so I tried with the word “heteroskedastic” and I found only 2 articles … wow! ok we need to remember that ADS is not complete, but at least I understand that astronomers doesn’t like this word

    12-09-2008, 2:05 pm
  4. hlee:

    Hmm. It is surprising that “heteroskedastic” only appears twice since I heard the word from Dr. Feigelson so many times during summer schools and SCMA meeting at Penn State. Your finding is very interesting. I appreciate that.

    To clarify, what I meant by “fault finding” is that some jargon that I claim MADS are likely to appear from your searches. By saying that your search finds its appearance, the particular words that I chose for a [MADS] posting, you’ve found my search mistake.

    12-09-2008, 7:14 pm
  5. mauro:

    It seems that the full text search look all the scanned articles up to 3 years from now.
    I looked for the sentence “extrasolar planets” (my research field) and the most recent references are of 2005.
    If I remember correctly this delay of 3 years is related to the policies of most of the astronomical journals.
    So from full text search we can have a “time biased” view of the MADS …

    12-10-2008, 9:37 am
  6. hlee:

    Thanks again for the valuable information. Such details on searching normally cannot be found and your information could benefit those who use ADS. I’m glad that I could re-taylor my searching strategies.

    12-12-2008, 2:12 pm
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