Ben Yu - Bits & Bytes (Page 2)

Redshift SQL Gotchas

If you're working within the AWS Cloud ecosystem, you've probably had to work with AWS Redshift, which is the de-facto solution for data warehousing and supporting business intelligence, reporting, data, and analytics tools. Here are 3 tips you should keep in mind when working with Redshift as your team's data-warehouse:

math

Birthday Attack

Alot of the crypotgraphic software we use relies on hashing and it's uniqueness guarantees to provide core functionality, such asauthentication, message integrity, message fingerprinting, data corruption detection, etc... Guaranteeing this uniqueness however is fundamentally impossible following from the Pigeonhole Principle if your input data size is going to be larger

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Zen Japanese Restaurant

Zen is arguably the best sushi restaraunt in the Greater Toronto Area. They offer an Omakase menu with consists of 13 pieces of nigiri and handroll, which will set you back around $120. My personal highlights were: Sea Perch with Shiso leaf - the flavour and textural contrasts were onpointA5

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Sushi Kashiba

Chef Shiro Kashiba started Seattle's first sushi bar in 1970 after years of grueling training alongside the world renown sushi chef Jiro Ono in Tokyo. In 2015, Shiro opened his new place Sushi Kashiba in the heart of Pike Place. I was lucky enough to get bar seating on a

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Sushi Bar Yasuda

As a die-hard Bourdain fan, I had to make a trip to Sushi Bar Yasuda. Making reservations in Japan is usually pretty difficult as a foreigner since most places will only accepts reservations through a conceirge. Luckily Yasuda was one of the rare places in Tokyo that had an online

math

Space Race

Another FiveThirtyEight Riddler.The President has bestowed upon you 1 billion dollars with the mission of getting us to an alien artifact as fast as possible! Here's whats available to you: Big Russian engines costing 400 million each. Buying one will reduce the trip time by 200 days. Buying two

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Impossible Puzzle

Another weekly FiveThirtyEight riddler, and this one's a mind-bender. Three very skilled logicians are sitting around a table — Barack, Pete and Susan. Barack says: “I’m thinking of two natural numbers between 1 and 9, inclusive. I’ve written the product of these two numbers on this paper that I’

math

Casino Game

The solution for this weeks FiveThirtyEight riddler is pretty nutty. The riddle is essentially: If you drew random numbers from a uniform distribution from [0,1], what is the expected number of draws you would perform until their sum exceeds 1? So let us define $$S_{n}$$ as the sum

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NBA Player Tracking

Since the 2013-14 season, the NBA has installed special cameras in every NBA stadium allowing teams to track every single player and ball movement, and digitize it into data that their data scientists can crunch into ever more sophisticated metrics on team and player performance. What's even more amazing is

quine

Tupper's self-referential formula

So here's something cool. This formula: $$\frac{1}{2} < \lfloor mod(\lfloor\frac{y}{17}\rfloor2^{-17\lfloor x \rfloor -mod(\lfloor y\rfloor,17)},2)\rfloor$$ will literally plot itself if you look at the right region. where k is this 543-digit integer: 960 939 379 918 958

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Tweeting with Markov Chains

I'm not sure why I find this so surprising, but it's a somewhat trivial task to write a program that can spew out somewhat coherent sentences, as long as you have a large corpus to work off. Markov Chains Markov Chains are essentially state machines with probabilities assigned to each

math

1 + 2 + 3 + ...

Here's something mind-blowing: If you take the sum of the first couple of natural numbers you get the triangle numbers: $$T_{1} = 1$$ $$T_{2} = 1 + 2$$ $$T_{3} = 1 + 2 + 3$$ $$T_{n} = (n)(n-1)/2$$ So essentially the series 1 + 2 + 3 + 4 + ... is the area of an

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大和

What better place to get sushi in Tokyo, than by going to an actual fish market? By the time we arrived at Tsukiji Fish Market (around 6:00AM in the morning), the lines were already pretty long. Daiwa Sushi (大和) had a significantly shorter wait. We probably only waited for

python

Towers of Hanoi

An age-old puzzle that's challenged kids and pancake chefs for ages: The goal of the puzzle is to move an entire stack of disks from one rod/plate to another with the following restrictions: Only one disk can be moved at a time. Each move consists of taking the upper

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Dragon Curve

The dragon curve or Heighway Dragon is a beautiful self-similar fractal first investigated by NASA physicists John Heighway, Bruce Banks, and William Harter. Jack [Heighway] came into my office (actually cubicle) and said that if you folded a one dollar bill repeatedly he thought it would make a random walk

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Analyzing NYC Subway Data with Python

MTA provides a public dataset of turnstile data per station since May 2010. We can grab weather data from Weather Underground, who kindly provides historical weather data in CSV format. You can also grab the same data through their API. Data Munging The data we collected so far usuable yet,

quine

Quine

Inspired by this impressive piece of engineering, I tried to write my one quine in CoffeeScript. The trick I used was to encode the entire file into decimal ASCII and store it in the data array. To rebuild the actual code, you convert it back to characters. This lets you