Magic Crystal
Over the few years, at the heart of astronomical researches, I see astronomers treat statistics like a magic crystal.
[ArXiv] Cross Validation
Statistical Resampling Methods are rather unfamiliar among astronomers. Bootstrapping can be an exception but I felt like it’s still unrepresented. Seeing an recent review paper on cross validation from [arXiv] which describes basic notions in theoretical statistics, I couldn’t resist mentioning it here. Cross validation has been used in various statistical fields such as classification, density estimation, model selection, regression, to name a few.
Where is ciao X ?
X={ primer, tutorial, cookbook, Introduction, guidebook, 101, for dummies, …}
I’ve heard many times about the lack of documentation of this extensive data analysis system, ciao. I saw people still using ciao 3.4 although the new version 4 has been available for many months. Although ciao is not the only tool for Chandra data analysis, it was specifically designed for it. Therefore, I expect it being used frequently with popularity. But the reality is against my expectation. Whatever (fierce) discussion I’ve heard, it has been irrelevant to me because ciao is not intended for statistical analysis. Then, out of sudden, after many months, a realization hit me. ciao is different from other data analysis systems and softwares. This difference has been a hampering factor of introducing ciao outside the Chandra scientist community and of gaining popularity. This difference was the reason I often got lost in finding suitable documentations.
[MADS] Parallel Coordinates
Speaking of XAtlas from my previous post I tried another visualization tool called Parallel Coordinates on these Capella observations and two stars with multiple observations (AL Lac and IM Peg). As discussed in [MADS] Chernoff face, full description of the catalog is found from XAtlas website. The reason for choosing these stars is that among low mass stars, next to Capella (I showed 16), IM PEG (HD 21648, 8 times), and AR Lac (although different phases, 6 times) are most frequently observed. I was curious about which variation, within (statistical variation) and between (Capella, IM Peg, AL Lac), is dominant. How would they look like from the parametric space of High Resolution Grating Spectroscopy from Chandra?
Another exciting news (with no use)
I wish I could chase all rabbits. Another rabbit I missed came to a realization by a friend, who was sure that I already knew this “call for papers” notice for the special issue of the signal processing magazine (SPM). Although those due dates were mistaken (the white paper due was several months back), my friend thought it would be useful for me and my group just in case I didn’t know about it. Yes, I was very delighted such things were on going. No doubt that I was disappointed when the white paper due was long gone.
News and related stories
I’m getting behind these days because of chasing too many rabbits. One of those rabbits is hunting online lectures useful for everyone. Prof. Feynman’s lectures have great reputations but they have been hard to come by. I once listened to a pirate version of his lecture tape with horrible sound quality. Thanks to Bill Gates and Microsoft Research, although it is a belated news, I’m very delighted to say “Feynman lectures are online.”
different views
An email was forwarded with questions related to the data sets found in “Be an INTEGRAL astronomer”. Among the sets, the following scatter plot is based on the Crab data.
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Astroinformatics
Approximately for a decade, there have been journals dedicated to bioinformatics. On the other hand, there is none in astronomy although astronomers have a long history of comprising a huge volume of catalogs and data archives. Prof. Bickel’s comment during his plenary lecture at the IMS-APRM particularly on sparse matrix and philosophical issues on choosing principal components led me to wonder why astronomers do not discuss astroinformatics.
worse than the Drake eq.
I was reading the June 2009 IMS bulletin on my way to Korea for the 1st IMS-APRM meeting. Then, I was in half shock and in half sadness. Something unlike than the Drake equation had happened.
Mt. Mathematics
Is Calculus the ultimate goal of mathematical education? Arthur Benjamin has a slightly subversive suggestion in this TED presentation.
Wavelet-regularized image deconvolution
A Fast Thresholded Landweber Algorithm for Wavelet-Regularized Multidimensional Deconvolution
Vonesch and Unser (2008)
IEEE Trans. Image Proc. vol. 17(4), pp. 539-549
Quoting the authors, I also like to say that the recovery of the original image from the observed is an ill-posed problem. They traced the efforts of wavelet regularization in deconvolution back to a few relatively recent publications by astronomers. Therefore, I guess the topic and algorithm of this paper could drag some attentions from astronomers.
how to trace?
I was at the SUSY 09 public lecture given by a Nobel laureate, Frank Wilczek of QCD (quantum chromodynamics). As far as I know SUSY is the abbreviation of SUperSYmetricity in particle physics. Finding such antimatter(? I’m afraid I read “Angels and Demons” too quickly) will explain the unification theory among electromagnetic, weak, and strong forces and even the gravitation according to the speaker’s graph. I’ll not go into the details of particle physics and the standard model. The reason is too obvious. 
Instead, I’d like to show this image from wikipedia and to discuss my related questions.
[MADS] Adaptive filter
Please, do not confuse adaptive filter (hereafter, AF) with adaptive optics (hereafter, AO). I have no expertise in both fields but have small experiences to tell you the difference. Simply put, AF is comparable to software as opposed to AO to hardware, which is for constructing telescopes in order to collect data with sharpness and to minimize time varying atmospheric blurring. When you search adaptive filter in ADS you’ll more likely come across with adaptive optics and notch filter.
Curious Cases of the Null Hypothesis Probability
Even though I traced the astronomers’ casual usage of the null hypothesis probability in a fashion of reporting outputs from data analysis packages of their choice, there were still some curious cases of the null hypothesis probability that I couldn’t solve. They are quite mysterious to me. Sometimes too much creativity harms the original intention. Here are some examples.