My Day at ACM Data Mining Camp III

My first time at ACM Data Mining Camp was so awesome, that I was thrilled the make the trip up to San Jose for the November 2010 version. In July, I gave a talk at the Emerging Technologies for Online Learning Symposium conference with a faculty member in the Department of Statistics, at the Fairmont. The place was amazing, and I told myself I would save up to stay there. This trip gave me an opportunity to check it out, and pretend that I am posh for a weekend ;). The night I arrived I had the best dinner and drinks at this place called Gordon Biersch. I had the best garlic fries and BBQ burger I have ever had. I ate it with a Dragonfruit Strawberry Mojito, the Barbados Rum Runner, and finished off with a Long Island Iced Tea, so the drinks were awesome as well. Anyway, to the point of this post…

The next morning I made the short trek to the PayPal headquarters for a very long 9am-8pm day. Since I came up here for the camp, I wanted to make the most of it and paid the $30 for the morning session, even though I had […]

Exciting Tools for Big Data: S4, Sawzall and mrjob!

This week, a few different big data processing tools were released to the open-source community. I know, I know, this is probably the 1000th blog post about this, and perhaps the train has left the station without me, but here I am.

Yahoo’s S4: Distributed Stream Computing Platform

First off, it must be said. S4 is NOT real-time map-reduce! This is the meme that has been floating around the Internets lately.

S4 is a distributed, scalable, partially fault-tolerant, pluggable platform that allows users to create applications that process unbounded streaming data. It is not a Hadoop project. A matter of fact, it is not even a form of map-reduce. S4 was developed at Yahoo for personalization of search advertising products. Map-reduce, so far, is not a great platform for dealing with streaming/non-stored data.

Pieces of data, apparently called events, are sent and consumed by a Processing Element (yes, PE, but not the kind that requires you to sweat). The PEs can do one of two things:

emit another event that will be consumed by another PE, or
publish some result

Streaming data is different from non-streaming data in that the user does not know how much data will be transmitted, and at what rate. Analysis on […]

Transactions, and Pondering their Use in Casinos

A couple of weeks ago, Bradford Cross of FlightCaster posted in Measuring Measures that transactions are the next big data category. I argue that they already are, and from reading his blog post, he seems to suggest this as well but I will admit that I think I missed his point. There are some clear examples of transactions and their importance:

Itemset Mining. Cross discusses this in his article. Financial transactions on sites like Amazon contain items (merchandise). Using these transactions, Amazon built a recommendation engine to recommend new items to customers on their website, and even customize deals for customers via email and on the site.
Wireless Localization. Fantasyland at The Magic Kingdom in Walt Disney World was to undergo a big overhaul to provide a personalized experience on transactions through the park. An RFID chip would be included in a ticket (or some type of document) and the visitor’s information from a survey would be transmitted to the attraction’s intelligent system. Such a system would also provide Disney a wealth of information about what attractions certain audiences visit, when, how often, and even what items a visitor may purchase during the day.

Website Conversion Path Optimization. A visit to a website […]

Lists of English Words

When I was a kid, I went through an 80s music phase…well, some things never change. “People just love to play with words…” Know that song? Anyway…

One of the biggest pains of text mining and NLP is colloquialism — language that is only appropriate in casual language and not in formal speech or writing. Words such as informal contractions (“gonna”, “wanna”, “whatcha”, “ain’t”, “y’all”) are colloquialisms and are everywhere on the Web. There is also a great deal of slang common on the Web including acronyms/emoticons (“LOL”, “WTF”) and smilies that add sentiment to text. There is also a less used slang called leetspeak that replaces letters with numbers (“n00b” rather than “noob”, “pwned” instead of “owned” and “pr0n” instead of “porn”).

There are also regionalisms which are a pain for semantic analysis but not so much for probabilistic analysis. Some examples are pancakes (“flapjacks”, “griddlecakes”) or carbonated beverages (“soda”, “pop”, “Coke”). Or, little did I know, “maple bars” vs. “Long Johns”. Now I am hungry. There are also words that have a formal and informal meeting such as “kid” (a young goat, or a child…same thing).


Linguists consider colloquialisms different than slang. Slang is informal language used by a specific […]

UCLA Statistics: Analyzing Thesis/Dissertation Lengths

As I am working on my dissertation and piecing together a mess of notes, code and output, I am wondering to myself “how long is this thing supposed to be?” I am definitely not into this to win the prize for longest dissertation. I just want to say my piece, make my point and move on. I’ve heard that the shortest dissertation in my program was 40 pages (not true). I heard someone from another school that their dissertation was over 300 pages. I am not holding myself to a strict limit, but I wanted a rough guideline. As a disclaimer, this blog post is more “fun” than “business.” This was just an analysis that I was interested in and felt that it was worth sharing since it combined Python, web scraping, R and ggplot2. It is not meant to be a thorough analysis of dissertation lengths or academic quality of the Department.

The UCLA Department of Statistics publishes most of its M.S. theses and Ph.D. dissertations on a website. It is not complete, especially for the earlier years, but it is a good enough population for my use.

Using this web page, I was able to extract information about each […]

Taking R to the Limit, Part II - Large Datasets in R

For Part I, Parallelism in R, click here.

Tuesday night I again had the opportunity to present on high performance computing in R, at the Los Angeles R Users’ Group. This was the second part of a two part series called “Taking R to the Limit: High Performance Computing in R.” Part II discussed ways to work with large datasets in R. I also tied in MapReduce into the talk. Unfortunately, there was too much material and I had originally planned to cover Rhipe, using R on EC2 and sparse matrix libraries.


My edited slides are posted on SlideShare, and available for download here.

Taking R to the Limit (High Performance Computing in R), Part 2 — Large Datasets, LA R Users' Group 8/17/10

View more presentations from Ryan Rosario.

Topics included:

bigmemory, biganalytics and bigtabulate
brief mention of Rhipe


The corresponding demonstration code is here.


Since this talk discussed large datasets, I used some, well, large datasets. Some demonstrations used toy data including trees and the famous iris dataset included in base R. To load these, just use the call library(iris) or library(trees).

Large datasets:

On-Time Airline Performance data from 2009 Data Expo. This Bash script will download all of the necessary data files and create a nice dataset […]

My Experience at Hadoop Summit 2010

This week I had the opportunity the trek up north to Silicon Valley to attend Yahoo’s Hadoop Summit 2010. I love Silicon Valley. The few times I’ve been there the weather was perfect (often warmer than LA), little to no traffic, no road rage and people overall seem friendly and happy. Not to mention there are so many trees it looks like a forest!

The venue was the Hyatt Regency Great America which seemed like a very posh business hotel. Walking into the lobby and seeing a huge crowd of enthusiasts and an usher every two steps was overwhelming!

After being welcomed by the sound of the vuvuzela, we heard about some statistics about the growth of Hadoop over the years. Apparently in 2008 there were 600 attendees to Hadoop Summit and in 2010 attendance grew to 1000. The conference started with three hours of keynotes and sessions that everyone attended in one room. The tone was somewhat corporate in nature, but there were also several gems in there about how Yahoo uses Hadoop:

A user’s click streams are mapped to latent interests, similar to mapping words to interests in topic models like LSA and LDA. Yahoo uses Hadoop to recompute a user’s […]

Hitting the Big Data Ceiling in R

As a true R fan, I like to believe that R can do anything, no matter how big, how small or how complicated: there is some way to do it in R. I decided to approach my large, sparse matrix problem with this attitude. But here I sit a broken man.

There is no “native” big data support built into R, even if using the 64bit build of R. Before venturing on this endeavor, I consulted with my advisor who reassured me that R uses the state of the art for sparse matrices. That was enough for me.

My Problem

For part of my Masters thesis, I wrote code to extract all of the friends and followers out to network degree 2 to construct a “small-world” snapshot of a user via their relationships. In a graph, nodes and edges grow exponentially as the degree increases. The number of nodes was on the order of 300,000. The number of edges I predict will be around 900,000. The code is still running. This means that a dense matrix would have size . Some of you already know how this story is going to end…

The matrix is very sparse.

Very sparse.

The raw data graph.log consists of an […]

Opening Statements on Markov Chain Monte Carlo

This quarter I am TAing UCLA’s Statistics 102C. Introduction to Monte Carlo Methods for Professor Qing Zhou. This course did not exist when I was an undergraduate, and I think it is pretty rare to teach Monte Carlo (minus the bootstrap if you count that) or MCMC to undergrads. I am excited about this class because to me, MCMC turns Statistics on its head. It felt like a totally different paradigm compared to the regression and data analysis paradigm that I was used to at the time. It also exposes students to the connection between Statistics/MCMC and other fields such as Computer Science, Genetics/Biology, etc.

I usually do not have much to talk about during week 1, especially if my class is the second day of the quarter. Today was an exception because I wanted to excite the class about this topic.

Some examples I discussed:

the general recipe for Monte Carlo methods
the bootstrap as an example of resampling, and R loops
computing and mention of Buffon’s Needle
scheduling/timetabling and occupancy/matching problems using stochastic search (simulated annealing, Tabu search etc.)
mention of genetic algorithms and swarm intelligence
PageRank as a Markov process
drawing a random sample of web pages using Random Walk Metropolis-Hastings
short inventory of fields […]

Some Code for Dumping Data from Twitter Gardenhose

Gardenhose is a Streaming API feed that continuously sends a sample (roughly 15% according to Ryan Sarver at the 140tc in September 2009) of all tweets to feed recipients. This is some code for dumping the tweets to files named by date and hour. It is in PHP which is not my favorite language, but works nonetheless. I received a few requests to post it, so here it is.


$username = ”;
$password = ”;

while(true) {
$file = fopen("http://" . $username . ":" . $password . "","r");

while($data = fgets($file))
$time = @date("YmdH");
if ($newTime!=$time)
$file2 = fopen("{$time}.txt","a");