Jul 29th, 2009| 01:02 am | Posted by hlee
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? Continue reading ‘[MADS] Parallel Coordinates’ »
Tags:
Classification,
clustering,
display,
EDA,
eye catcher,
GGobi,
Inselberg,
parallel coordinates,
visualization Category:
Algorithms,
arXiv,
Cross-Cultural,
Data Processing,
High-Energy,
Jargon,
Methods,
Spectral,
X-ray |
3 Comments
Jul 27th, 2009| 07:37 am | Posted by hlee
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. Continue reading ‘Another exciting news (with no use)’ »
Jul 27th, 2009| 06:09 am | Posted by hlee
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.” Continue reading ‘News and related stories’ »
Jul 12th, 2009| 07:33 pm | Posted by hlee
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.
Continue reading ‘different views’ »
Tags:
ANOVA,
block design,
crab nebula,
F-test,
gaussinity,
integral,
light curve Category:
Astro,
Cross-Cultural,
gamma-ray,
High-Energy,
Jargon,
Objects,
Uncertainty |
Comment
Jul 12th, 2009| 07:21 pm | Posted by hlee
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. Continue reading ‘Astroinformatics’ »
Tags:
astroinformatics,
bioinformatics,
catalog,
dimension reduction,
journals,
penalize,
regularization,
sparse matrix,
variable selection Category:
Astro,
Cross-Cultural,
Data Processing,
Imaging,
Jargon,
Stat |
1 Comment
Jul 4th, 2009| 12:59 am | Posted by hlee
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. Continue reading ‘worse than the Drake eq.’ »
Tags:
bump hunting,
chain rule,
computational geometry,
Drake eq.,
IJ Good,
K Worsley,
obituary,
spectral analysis Category:
Astro,
Cross-Cultural,
Jargon,
Spectral,
Stat |
Comment
Jun 12th, 2009| 03:47 pm | Posted by hlee
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. Continue reading ‘Wavelet-regularized image deconvolution’ »
Tags:
bound optimization,
deconvolution,
image processing,
impulse response,
MM algorithm,
PSF,
regularization,
restoration,
thresholding,
wavelet Category:
Algorithms,
arXiv,
Data Processing,
Fitting,
Imaging,
Jargon,
Methods,
Quotes,
Stat |
Comment
Jun 11th, 2009| 03:52 pm | Posted by hlee
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.
Continue reading ‘how to trace?’ »
Tags:
cliche,
collion,
identifiability,
identification,
irony,
LHC,
Power,
reconstruction,
source detection,
subparticle,
supersymmetry,
SUSY,
TRACE,
type I error,
Type II error,
uncertainty principle,
unification,
youtube Category:
Cross-Cultural,
Data Processing,
High-Energy,
Misc,
Quotes,
Uncertainty |
Comment
Jun 4th, 2009| 04:36 pm | Posted by hlee
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. Continue reading ‘[MADS] Adaptive filter’ »
Jun 2nd, 2009| 03:03 am | Posted by hlee
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. Continue reading ‘Curious Cases of the Null Hypothesis Probability’ »
Tags:
cases,
chi-sq,
curious,
degree of freedom,
dof,
F-test,
goodness-of-fit test,
Model Selection,
null hypothesis probability,
p-value,
reduced chi-sq Category:
arXiv,
Astro,
Cross-Cultural,
Fitting,
Methods,
Uncertainty |
3 Comments
Jun 1st, 2009| 09:51 pm | Posted by hlee
How would you assign orders to multivariate data? If you have your strategy to achieve this ordering task, I’d like to ask, “is your strategy affine invariant?” meaning that shift and rotation invariant. Continue reading ‘[MADS] data depth’ »
Tags:
break points,
data depth,
MADS,
mean,
median,
multivariate,
nonparametric,
order,
parasite,
quantile,
robust,
sort,
vertebrate Category:
Algorithms,
arXiv,
Cross-Cultural,
Jargon,
Stat |
Comment
May 28th, 2009| 11:54 pm | Posted by hlee
This simple law, despite my trial of full text search, was not showing in ADS. As discussed in systematic errors, astronomers, like physicists, show their error components in two additive terms; statistical error + systematic error. To explain such decomposition and to make error analysis statistically rigorous, the law of total variance (LTV) seems indispensable. Continue reading ‘[MADS] Law of Total Variance’ »
Tags:
additive,
bias,
law of total variance,
MADS,
mathematical statistics,
mean integrated square error,
mean square error,
MISE,
mse,
probability theory,
variance Category:
Algorithms,
Data Processing,
Jargon,
News,
Stat,
Uncertainty |
Comment
May 21st, 2009| 05:55 pm | Posted by hlee
Among billion objects in our Galaxy, outside the Earth, our Sun drags most attention from astronomers. These astronomers go by solar physicists, who enjoy the most abundant data including 400 year long sunspot counts. Their joy is not only originated from the fascinating, active, and unpredictable characteristics of the Sun but also attributed to its influence on our daily lives. Related to the latter, sometimes studying the conditions on the Sun is called space weather forecast. Continue reading ‘space weather’ »
Tags:
classifier,
forecast,
logistic regression,
machine learning,
predictor,
response,
space weather,
Sun,
sunspot,
SVM,
test data,
training data,
weather Category:
arXiv,
Astro,
Cross-Cultural,
Data Processing,
Imaging,
Jargon,
Stars,
Stat |
Comment
May 18th, 2009| 12:18 pm | Posted by hlee
My understandings of “robustness” from the education in statistics and from communicating with astronomers are hard to find a mutual interest. Can anyone help me to build a robust bridge to get over this abyss? Continue reading ‘Robust Statistics’ »
Tags:
break point,
Huber,
nonparametric,
robust,
Rousseeuw,
Tukey Category:
Bayesian,
Frequentist,
Jargon,
MCMC,
Methods,
Quotes,
Stat,
Uncertainty |
Comment
May 7th, 2009| 02:22 pm | Posted by hlee
Almost 100 years ago, A.S. Eddington stated in his book Stellar Movements (1914) that
…in calculating the mean error of a series of observations it is preferable to use the simple mean residual irrespective of sign rather than the mean square residual
Such eminent astronomer said already least absolute deviation over chi-square, if I match simple mean residual and mean square residual to relevant methodologies, in order. Continue reading ‘a century ago’ »
Tags:
chi-square minimization,
Eddington,
inference,
LAD,
Laplace,
mse,
PyMC,
Python,
R.A.Fisher,
utility function Category:
Astro,
Cross-Cultural,
Quotes,
Stat,
Uncertainty |
Comment