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Posts

August 04, 2015

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10:52 PM | What’s in a browser language default?
Ok, so this is from Saturday and I hadn’t seen it until this morning, so perhaps it should just be left in obscurity, but: Claims foreign buyers are increasingly snapping up Auckland houses have been further debunked, with data indicating only a fraction of visitors to a popular real estate website are Asian. Figures released by […]
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9:47 PM | Call for nominations: Prize in Game Theory and Computer Science
From Rakesh Vohra: The Prize in Game Theory and Computer Science of the Game Theory Society in Honour of Ehud Kalai was established in 2008 by a donation from Yoav Shoham in recognition of Ehud Kalai’s role in promoting the connection of the two research areas. The Prize will be awarded at the Fifth World […]
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4:15 PM | Hydrogen spectrum: Lyman, Balmer and Paschen series
Reference: Carroll, Bradley W. & Ostlie, Dale A. (2007), An Introduction to Modern Astrophysics, 2nd Edition; Pearson Education – Chapter 5, Problems 5.10 – 5.11. The energy levels in the hydrogen atom are When the electron jumps between these levels it absorbs (when jumping to a higher level) or emits (lower) a photon with an […]
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3:05 PM | Orange is the new stat
I've been reading Piper Kerman's Orange Is the New Black, a memoir by a woman who served 11 months in a federal prison.  One of the recurring themes is the author's surprise at the length of the sentences her fellow prisoners are serving, especially the ones convicted of drug offences.  In my opinion, she is right to be shocked.About half of federal prisoners were convicted of drug crimes, according to this fact sheet from the US Sentencing Commission (USSC).  In […]
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2:48 PM | Gravitational hydrogen atom
Reference: Carroll, Bradley W. & Ostlie, Dale A. (2007), An Introduction to Modern Astrophysics, 2nd Edition; Pearson Education – Chapter 5, Problem 5.9. To see that gravity is much weaker than the electrostatic force, we can repeat Bohr’s semi-classical derivation of the hydrogen energy levels, replacing the Coulomb force with the Newtonian gravitational force. We […]
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1:41 PM | Pro Publica’s new Surgeon Scorecards
Skyler Johnson writes: You should definitely weigh in on this… Pro Publica created “Surgeon Scorecards” based upon risk adjusted surgery compilation rates. They used hierarchical modeling via the lmer package in R. For detailed methodology, click the methodology “how we calculated complications” link, then atop that next page click on the detailed methodology to download […] The post Pro Publica’s new Surgeon Scorecards appeared first on Statistical […]
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1:16 PM | Ariel Procaccia's Computers and Thought Award Talk at IJCAI 2015
[Thank you to Felix Brandt for the link]
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1:13 PM | Cplex slides
Slides from ISMP 2015 by CPLEX Optimization Studio engine developers A number of developers from both engines (CPLEX and CPO) in CPLEX Optimization Studio were in Pittsburgh mid-July for the ISMP 2015 conference. The slides that they presented are available on the IBM Decision Optimization community at https://www.ibm.com/developerworks/community/wikis/home?lang=en#!/wiki/W1a790e980a7d_49c5_963d_2965e5d01401/page/ISMP%202015 These presentations describe how CPO and CPLEX performance were […]
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1:00 PM | Harsh Discipline and No-excuse Charters continued
[I posted this at the teaching blog a few months ago, but it's a natural follow-up to the previous post on harsh discipline.]When discipline crosses the lineI've been meaning to write this up for a while now, but recent news about attrition (see here and here for the conversation up to now) has brought the issue back to the forefront.When you take a close at the increasingly dominant charter model (the "no-excuses" school) and some of the highly touted success stories (such as the […]
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12:38 PM | Last digits of Fibonacci numbers
If you write out a sequence of Fibonacci numbers, you can see that the last digits repeat every 60 numbers. The 61st Fibonacci number is 2504730781961. The 62nd is 4052739537881. Since these end in 1 and 1, the 63rd Fibonacci number must end in 2, etc. and so the pattern starts over. It’s not obvious that the cycle […]
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11:57 AM | Occupy Summer School is in the New Yorker!
I’m super proud to say that Alex Carp, a journalist who was present for more than half of Occupy Summer School last month, did a fantastic job of writing up the OSS experiment for the New Yorker’s Talk Of The Town column. Here is Alex’s New Yorker Piece, called “Protest U,” please enjoy! We also got […]
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7:39 AM | The list monad in Perl and Python
A few months ago I wrote an article about using Haskell's list monad to do exhaustive search, with the running example of solving this cryptarithm puzzle: S E N D + M O R E ----------- M O N E Y (This means that we want to map the letters S, E, N, D, M, O, R, Y to distinct digits 0 through 9 to produce a five-digit and two four-digit numerals which, when added in the indicated way, produce the indicated sum.) At the end, I said: It would be an interesting and pleasant […]
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5:00 AM | GitXiv: Because People Still Don't Care About You and Your Algorithm
  If you have followed Nuit Blanche long enough, you know that I take a specific interest in papers that release an attendant implementation. As a matter of fact, each implementation released in the wild is listed under the implementation tag (and shown prominently every end of the month in the Nuit Blanche monthly reviews).  Since 2012, Nuit Blanche has featured  380 blog entries with one implementation.  Much like the listing of codes available in the Big Picture […]
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4:40 AM | Stan Meetup Talk in Ann Arbor this Wednesday (5 Aug 2015)
I (Bob) will be presenting an overview of (R)Stan at the Ann Arbor R User Group meetup this Wednesday night (5 August 2015) at 7 PM. To see the abstract and register to attend: RStan: Statistical Modeling Made Easy with Bob Carpenter Wednesday, Aug 5, 2015, 7:00 PM Barracuda Networks317 Maynard St Ann Arbor, MI […] The post Stan Meetup Talk in Ann Arbor this Wednesday (5 Aug 2015) appeared first on Statistical Modeling, Causal Inference, and Social Science.
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3:05 AM | The Spirit of the Rules
I just read the book One Man Guy by Michael Barakiva. (Pretty good, but has some problems). I wanted to share a scene from the book. (Emphasis mine.) “Does that mean your absence last Friday, unlike your earlier absences this semester, was unexcused?” Mr. Weedin asked. “It does,” Alek admitted. “Mr. Khederian, you clearly have a strong […]

August 03, 2015

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8:55 PM | Learning about Neural Spike Train Analysis and More at the SAMSI CCNS Summer School
This week’s blog entry is written by SAMSI’s Kenan Fellow, Alexandra Solender who is the Science Department Chair at Holly Springs High School and teaches AP Physics C, Honors Physics. She is also the Science Olympiad Coach and SNHS Advisor. … Continue reading →
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7:32 PM | The Monosyllabic Raven
David Morice rewrote Edgar Allen Poe’s poem The Raven in words of one syllable. Here is the first stanza: Once at twelve on one night’s drear, ’twas while I, weak and tired thought here On the words in lots of quaint and odd old tomes of mind’s lost lore, While I dozed, so near a nap, there […]
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6:20 PM | Energy levels of hydrogen: Bohr’s semi-classical derivation
Reference: Carroll, Bradley W. & Ostlie, Dale A. (2007), An Introduction to Modern Astrophysics, 2nd Edition; Pearson Education – Chapter 5, Problem 5.8. We’ve seen how to derive the Bohr formula for the energy levels in hydrogen by solving the Schrödinger equation, but this isn’t the way Bohr originally derived the formula; in fact, he […]
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4:00 PM | Farewells and other goings on
It’s been a while since I last wrote a post here… The spring was full of duties pulling me in lots of different directions, but now (finally) the summer has given me a chance to dig myself out and now I’m finally back. Of course, lot’s has been going on at Caltech and in RSRG in […]
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2:26 PM | The plagiarist next door strikes back: Different standards of plagiarism in different communities
Commenters on this blog sometimes tell me not to waste so much time talking about plagiarism. And in the grand scheme of things, what could be more trivial than plagiarism in an obscure German book of chess anecdotes? Yet this is what I have come to talk with you about today. As usual, I will […] The post The plagiarist next door strikes back: Different standards of plagiarism in different communities appeared first on Statistical Modeling, Causal Inference, and Social Science.
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1:53 PM | Linking Data to a Visio Drawing
I enjoy collecting and occasionally creating pins for my Pinterest collection. There was one pin that I saw (Figure 1) that I thought would be a good exercise to use when I conduct training classes in Visio and Excel. This post will use a simple Excel table of planetary orbit data to drive the creation of similar graphic in Visio. I will make one change to the information contained in Figure 1 – I will add Pluto because I still like to think of it as a planet. I will also remove the black […]
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1:00 PM | On deck this week
Mon: The plagiarist next door strikes back: Different standards of plagiarism in different communities Tues: Pro Publica’s new Surgeon Scorecards Wed: How Hamiltonian Monte Carlo works Thurs: When does Bayes do the job? Fri: Here’s a theoretical research project for you Sat: Classifying causes of death using “verbal autopsies” Sun: All hail Lord Spiegelhalter! The post On deck this week appeared first on Statistical Modeling, Causal Inference, and Social Science.
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1:00 PM | Harsh Discipline and No-excuse Charters
One of the disconnects I've noticed between educators and many education researchers (particularly those who come from outside of the field) is that the educators tend to have a more complex, multivariate view of student outcomes, while the researchers are often prone to a particularly severe form of the tyranny of measurement where they ignore not only the difficult-to-measure but also the easy-to-measure if it isn't part of their small set of approved metrics.Emotional damage is notoriously […]
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11:10 AM | Should Aunt Pythia go video?
What, what? My friend Becky Jaffe sent me this video of Tig Notaro giving advice: I thought it was moving and intimate, just like an advice column should be. What do you think, should Aunt Pythia go video? Pros for Aunt Pythia going video: the connection with the audience, doesn’t have to wear anything below […]
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10:00 AM | Going Bananas #2: A Needle In A Haystack
Now I’m gonna tell my momma that I’m a traveller, I’m gonna follow the sun (The Sun, Parov Stelar) Inspired by this book I read recently, I decided to do this experiment. The idea is comparing how easy is to find sequences of numbers inside Pi, e, Golden Ratio (Phi) and a randomly generated number. … Continue reading Going Bananas #2: A Needle In A Haystack →
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5:39 AM | Zio Ziegler in Irvine
Street art? In Irvine? Apparently, now, the answer is yes. Local clothing manufacturer Tillys somehow persuaded the planning commission to allow them to commission Zio Ziegler (new Wikipedia article) to decorate one of their warehouses, right next to interstate 405, where approximately 240,000 daily drivers will see it.You can't exactly stop on the freeway to take photos, but I found enough other more accessible vantage points to get a few shots:( The rest of the photos )
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5:00 AM | Efficient Compressive Phase Retrieval with Constrained Sensing Vectors
Interesting that a random gaussian projection helps in the decoupling of two regularization terms in a nonlinear compressive sensing problem.  Efficient Compressive Phase Retrieval with Constrained Sensing Vectors by Sohail Bahmani, Justin Romberg We propose a new approach to the problem of compressive phase retrieval in which the goal is to reconstruct a sparse vector from the magnitude of a number of its linear measurements. The proposed framework relies on constrained sensing vectors […]
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1:55 AM | There’s nothing like a good joke
We (already!) have a Stat of the Week nomination, for the Herald’s Conservative estimates are that the average man will lose 12,547 umbrellas during his lifetime. At first sight this looks like deadpan humour rather than a statistic, but in that case you’d expect a by-line on the piece.  The Google, which knows all and tells […]
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12:15 AM | Warm-Ups 2.0
Back at the end January, I created (i.e. compiled from all the great stuff out there) a set of warm-ups which I used in one of my classes last semester. Each student received a duo-tang* on the first day of classes with all 18 weeks of warm ups. These did not leave the classroom.I have updated my warm-ups to include Which One Doesn't Belong?, Open Middle, along with better balance benders. There are also now quadratic visual patterns thrown in from week 6.Here is the DropBox link to the Word […]

August 02, 2015

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10:57 PM | MIQP root
Sometimes I see solver logs that makes me wonder… Here is an example: MIQP Presolve eliminated 1 rows and 1 columns. Reduced MIQP has 3400 rows, 10400 columns, and 2410400 nonzeros. Reduced MIQP has 8000 binaries, 0 generals, 0 SOSs, and 0 indicators. Reduced MIQP objective Q matrix has 2400 nonzeros. Presolve time = 1.77 sec. (674.81 ticks) Probing time = 0.16 sec. (93.32 ticks) Tried […]
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