Welcome to tobilehman.com!
%  

# time posts

## Fourier's Finches: A Primer on Digital Audio

As far as I know, Jean-Baptiste Joseph Fourier never took an interest in birds, but he was a legendary mathematician who’s work enabled our modern techniques for digital audio. Fourier discovered a mathematical transformation that converts a time signal into a frequency signal. This would let us, for example, record a finch’s birdsong and decompose it to find the major frequencies. This would be useful for compressing the audio file. By studying the anatomy of the ear, you can throw away all the frequencies that the ear wouldn’t hear anyway.

## Year of the Rabbit

The year 2022 for me was good, better than I expected. The things I am most greatful for: Our third child, first daughter, was born β€οΈ I joined a great team at SUSE We sold our Renton house and bought our perfect house in Portland We met a family who adopted one of our rabbits, which lead to a cluster of amazing synchronicities that continue to surprise me The last part is symbolically appropriate going into 2023, which in the Chinese zodiac is the Year of the Rabbit.

## Book Review: Time Loops

The book Time Loops by Eric Wargo makes a careful argument for the reality of precognitive dreams. My personal interest in this topic has to do with my obsession with time and to an extent, time travel. The author starts the book by summarizing a number of examples of dreams that came true, and closely studies an early dream pioneer named J.W. Dunne who wrote An Experiment with Time. What stands out about Dunne is how he made the distinction between dreaming about events out in the world vs events as experienced by the future self.

## Latency Numbers Every Programmer Should Know

There’s an indispensible file called Latency Numbers Every Programmer Should Know, originally by Jeff Dean of Google. I use a Roam Research plugin to do spaced repetition and memorize these numbers. But memorizing them is not good enough, I should also measure these numbers and see how close the values are in practice. I created a Repl in Go to directly measure these numbers. I started with mutex lock/unlock. Locally, I get about 19ns, but the repl gives me between 12-14ns.

## Qubits and the Multiverse: how to πππ-ππππππ your life

Have you ever had a decision that was hard to make because both sides of the decision were great in their own way? Where you stress over the decision and wish you could split into two copies of yourself? Some decision theorists recommend flipping a coin, but there is a better way. Coins are made of lots of atoms, and many of those atoms are entangled with each other and with the environment.

## Unix Epoch Time

Unix Epoch Time is the number of seconds since 1970-01-01 00:00:00 UTC (Coordinated Universal Time zone). This arbitrary moment in time is defined as “the beginning”, and this timezone used as the reference. The more you work with times, dates, time zones and daylight saving time, the more you will come to appreciate constant points of reference like this. Below is a tool for working with and understanding dates and times and epoch numbers.

## The Topology of Time Travel Stories

Everyone needs an obscure useless skill. β @Noahpinion Mine is identifying the topology of time travel stories. Click here if you know what topology is and just want to get to the time travel stuff a brief introduction to topology The original study of shapes was geometry, popularized by a Greek mathematician named Euclid. Starting about 2000 years after that, a Swiss mathematician named Euler (pronounced “Oiler”) accidentally inventented topology while trying to solve the Seven Bridges of KΓΆnigsberg problem.

## Time in Physics

In 1666, when the Plague was ripping through England, Isaac Newton went into quarantine outside the city and developed calculus. Calculus is an application of Euclid’s geometry to problems involving time. Geometry models space, calculus models space and time. The reason the ancient Greeks didn’t develop calculus is because of tools. The ancient Greeks had rulers and compasses but not reliable clocks. They used the rulers and compasses to do geometry, and discovered many eternal truths about space and shape.

## Timelapse

I have a fascination with time. Two years ago, our family planted a tree in our back yard. A few months prior, my dad and I built an overhang that provides shade. I used a pillar supporting the overhang to point this timelapse camera at the tree. I bought that camera because of it’s low battery usage, and how it uses standard JPEGs on a standard SD card. That gives me raw material to compress a large amount of time into a nice video.

## The Long Now Foundation

The world is changing fast, the last 100 years saw the creation of a global network of airplanes, computers, the internet, nuclear energy, and the discovery, sequencing and editing of the genome. The tendency of politics is to focus on the next election (at least in democracies). The tendency of business is to focus on the next quarter. The engines of our fast-changing modern world tend to focus our attention on the narrow world of right now.