-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»
-Jan 20th, 2009| 01:59 pm | Posted by hlee
Someone emailed me for globular cluster data sets I used in a proceeding paper, which was about how to determine the multi-modality (multiple populations) based on well known and new information criteria without binning the luminosity functions. I spent quite time to understand the data sets with suspicious numbers of globular cluster populations. On the other hand, obtaining globular cluster data sets was easy because of available data archives such as VizieR. Most data sets in charts/tables, I acquire those data from VizieR. In order to understand science behind those data sets, I check ADS. Well, actually it happens the other way around: check scientific background first to assess whether there is room for statistics, then search for available data sets. …Continue reading»
Tags:
archive,
ascii,
catalog,
CDA,
data analysis,
data mining,
database,
Gator,
globular cluster,
inference,
massive data,
multimodality,
multiple populations,
NED,
SDSS,
statistical inference,
statistician,
streaming data,
table,
tabulated,
visieR Category:
Algorithms,
Astro,
Cross-Cultural,
Data Processing,
Jargon,
Meta,
Nuggets,
Objects
-Oct 18th, 2008| 11:27 pm | Posted by vlk
The iPhone is an amazing device. I have heard that some people use it as a phone, too, but it really is an extraordinary portable computer. It is faster and more powerful than the Sparcstations I used as a grad student, and will fit into your pocket. And most importantly, you can fit an entire planetarium on it.
There are many good planetarium programs that you can access on laptops, but it is really not that much fun to lug them around on camping trips or even out on to the roof at night. But now, thanks to the iPhone (and the iPod Touch) there has been a great leap forward. …Continue reading»
Tags:
AppStore,
GoSkyWatch,
iAstronomica,
iPhone,
iPod Touch,
iStellar,
planetarium,
review,
Starmap Category:
Astro,
Misc,
News,
Optical
-Apr 25th, 2008| 01:48 am | Posted by hlee
One of the speakers from the google talk series exemplified model based clustering and mentioned the likelihood ratio test (LRT) for defining the number of clusters. Since I’ve seen the examples of ill-mannerly practiced LRTs from astronomical journals, like testing two clusters vs three, or a higher number of components, I could not resist indicating that the LRT is improperly used from his illustration. As a reply, the citation regarding the LRT was different from his plot and the test was carried out to test one component vs. two, which closely observes the regularity conditions. I was relieved not to find another example of the ill-used LRT. …Continue reading»
-Apr 8th, 2008| 04:32 pm | Posted by vlk
For people in the Boston area, a cornucopia of talks on Google Sky in the near future.
- Hunting for Needles in Massive Astronomical Data Streams
Wednesday, April 9, 2008 at 4pm
Room 330, 60 Oxford St.
Ryan Scranton, Google Sky Team
- Inside Google Sky
Wednesday, April 9, 2008 at 8pm
Room 105, Emerson Hall
Andrew Connolly, Google Sky Team
- Sky in Google Earth
Tuesday, April 15, 2008 at 1pm
Phillips Auditorium, 60 Garden
Alberto Conti & Carol Christian, STScI
-Sep 8th, 2007| 02:31 pm | Posted by vlk
Google Sky is good for a quick look “what’s that you just saw over there?”, but not for anything more than that. Not yet anyway. Mind you, I think it is a good thing. It is easy to use, and definitely worth a look as an astronomy popularization tool. But there are a number of astro visualization programs that can (so to speak) beat the pants off Google Sky with one hand tied behind the back. Check these out (all open source): …Continue reading»
-Sep 7th, 2007| 01:46 am | Posted by hlee
Ah..Sky in Google Earth made an arxiv appearance [arxiv/astro-ph:0709.0752], Sky in Google Earth: The Next Frontier in Astronomical Data Discovery and Visualization by R. Scranton et al.
-Jul 25th, 2007| 02:28 am | Posted by hlee
Since I began to subscribe arxiv/astro-ph abstracts, from an astrostatistical point of view, one of the most frequent topics has been photometric redshifts. This photometric redshift has been a popular topic as the catalog of remote photometric object observation multiplies its volume and sky survey projects in multiple bands lead to virtual observatories (VO – will discuss in the later posting). Just searching by photometric redshifts in google scholar and arxiv.org provides more than 2000 articles since 2000.
…Continue reading»
Tags:
cosmology,
distance estimation,
Lutz-Kelker bias,
machine learning,
Malmquist bias,
Photometric Redshift,
spectrum,
survey,
VO Category:
Algorithms,
arXiv,
Data Processing,
Galaxies,
Stat